DESCRIPTION
BRAKE CYLINDER DEVICE AND UNIT BRAKE USING THE SAME
Technical Field
The present invention relates to a brake cylinder
device capable of actuating both a normal brake and a
spring brake used as a parking brake.
Background Art
For example, in a brake system for railway vehicles,
known is a brake cylinder device capable of actuating both
a normal brake which is used in a normal operation and
actuated by pressure air and a spring brake which is used
in a prolonged parking and actuated by a spring force even
in the absence of pressure air (refer to, for example.
Patent Document 1: the Japanese Patent Application Laid
Open No.63-125834). In the brake cylinder device described
in Patent Document 1 (Fig. 2), when the normal brake is
used which is composed of a first cylinder chamber 1, a
first piston 6, a first spring 7 and a first push rod 8,
pressure air is supplied to the first cylinder chamber 1
from a first air source 2, thereby generating a braking

force. Therefore, when the spring brake is used which is
composed of a second cylinder chamber 9, a second piston 14,
and a second spring 15, pressure air is supplied to the
second cylinder chamber 9 via a double check valve 12 from
a second air source 10 different from the first air source.
Then, the pressure air from the first air source 2 is
supplied to the first cylinder chamber 1 and also supplied
to the second cylinder chamber 9 via the double check valve
12. Thereby, it is possible to prevent an excessive braking
actuation due to a simultaneous operation of the spring
brake while the normal brake is in operation.
However, in the brake cylinder device described in
Patent Document 1 (Fig. 2), there is a problem that the
double check valve is placed into piping, by which the
piping is complicatedly increases the possibility of
malfunction and deteriorates the reliability of brakes. As
a brake cylinder device made with a view toward solving
this problem, such a device is described in Patent Document
1 (in Fig. 1 and others) that is provided with a normal
brake having a first piston 22 and a first spring 25 on the
front side of the first piston 22, a spring brake having a
second piston 23 and a second spring 26 at the back thereof,
a cylinder chamber 24 formed between the first piston 22
and the second piston 23 and having a pressure-air
supply/discharge hole 45, and an engagement/disengagement

means 27 capable of retaining and releasing the second
piston 23 at a retracted position against the action force
of the second spring 26.
Disclosure of the Invention
However, the brake cylinder device described in
Patent Document 1 requires the engagement/disengagement
means 27 capable of retaining and releasing the second
piston 23 of the spring brake at the retracted position
against the action force of the second spring 26. Therefore,
in order to realize the engagement/disengagement means
27,required are various mechanisms such as a sleeve 46, a
ball 47, a cylindrical body 48, a third spring 49, a lid
body 50 and a locked portion 44 installed on the second
piston 23. Thus, a problem is posed that although a double
check valve can be omitted, an engagement/disengagement
means made up of a complicated mechanism is required, by
which the brake cylinder device is complicated in
constitution to result in an increased cost.
The present invention has been made in view of the
above situation, relating to a brake cylinder device
capable of actuating both a normal brake and a spring brake
used as a parking brake, an object of which is to provide a
brake cylinder device which can omit a double check valve

often resulting in a complicated piping, a greater number
of components or an increased maintenance load and also
realize the prevention of a simultaneous operation of the
normal brake and the spring brake by using a simple
mechanism. The present invention also provides a unit brake
using the above-described brake cylinder device.
The present invention relates to a brake cylinder
device and a unit brake using the brake cylinder device.
Therefore, the brake cylinder device of the present
invention and the unit brake using the same have the
following features for attaining the above described
object. In other words, the brake cylinder device of the
present invention and the unit brake using the same have
the following features solely or in an appropriate
combination of them.
A first feature of the brake cylinder device of the
present invention for attaining the above-described object
is that
the brake cylinder device comprising: a normal brake having
a first piston, a rod projecting from the first piston, a
first pressure chamber and a first spring, the first piston
being subjected to the action of the first pressure chamber
and the first spring sandwiching the first piston
therebetween, thereby moving the first piston in a braking
direction against an urging force of the first spring when

a supply of pressure fluid to the.first pressure chamber is
started, a braking force being generated with the movement
of the first piston in the braking direction; a spring
brake having a second piston installed so as to move in an
axial direction of the rod and penetrated by the rod, a
second pressure chamber and a second spring, the second
piston being subjected to the action of the second pressure
chamber and the second spring sandwiching the second piston
therebetween, threby moving the second piston in the
braking direction against an urging force of the second
spring when a supply of pressure fluid to the second
pressure chamber is stopped and a discharge of pressure
fluid from the second pressure chamber is started; and a
third pressure chamber arranged ,separated from the second
pressure chamber, on the opposite side of the second spring
relative to the second piston, the second piston being
subjected to the action of the third pressure chamber,
threby moving the second piston in an anti-braking
direction, that is a direction reverse to the braking
direction, against an urging force of the second spring
when pressure fluid supplied to the first pressure chamber
is supplied to the third pressure chamber.
According to the above constitution, the pressure
fluid to be supplied to the first pressure chamber is
supplied to the third pressure chamber, by which the third

pressure chamber allowing the second piston to be move in
the anti-braking direction against an urging force of the
second spring so as to act on the second piston as a
pressure chamber divided and sectioned from the second
pressure chamber. Therefore, while the normal brake is in
operation, the third pressure chamber acts to move the
second piston in the anti-braking direction. It is, thereby,
possible to prevent a simultaneous operation of the normal
brake and the spring brake. Further, a simple mechanism of
installing the third pressure chamber that is supplied
pressure fluid from the first pressure chamber without a
necessity for installing a double check valve which may
often result in a complicated piping, a greater number of
components or an increased maintenance load makes it
possible to prevent a simultaneous operation of the normal
brake and the spring brake.
As a result, the mechanism can be simplified to
greatly reduce costs.
As described above, according to the constitution of
the present invention, the brake cylinder device capable
of actuating both a normal brake and a spring brake used
in a parking brake can be assembled without a double check
valve, and the simple mechanism is used to prevent a
simultaneous operation of the normal brake and the spring
brake.

Further, a second feature of the brake cylinder
device of the present invention is that in which the second
pressure chamber is arranged along the circumferential
direction on the outer circumference of the second piston
and the third pressure chamber is arranged along the
circumferential direction on the inner circumference of the
second piston.
According to this constitution, since the second
pressure chamber and the third pressure chamber are
arranged respectively on the outer circumference of the
second piston and on the inner circumference thereof in the
circumferential direction, the second piston can be
uniformly urged in an axially symmetrical manner against an
urging force of the second spring even upon an actuation of
either the second pressure chamber or the third pressure
chamber. Therefore, it is possible to realize a mechanism
for uniformly urging the second piston by a simple
constitution in which the second pressure chamber is
arranged on the outer circumference and the third pressure
chamber is arranged on the inner circumference. In addition,
it is not necessary to install an additional mechanism for
uniformly urging the second piston, thus making the
mechanism simple to reduce costs.
Further, a third feature of the brake cylinder device
of the present invention is that in which the second piston

is provided with a cylindrical wall disposed along the
circumferential direction of the second piston and
projected in the braking direction to be formed into a
cylindrical shape, thereby sectioning the second pressure
chamber and the third pressure chamber, and the cylindrical
wall is slidingly in contact with an inner cylindrical
portion formed in a tubular shape along the circumferential
direction of the second piston inside a cylinder main body
including the normal brake and the spring brake.
According to this constitution, a simple mechanism is
provided in which the cylindrical wall slidingly in contact
with the inner cylindrical portion formed inside the
cylinder main body is installed on the second piston to
section the second pressure chamber and the third pressure
chamber making it possible to easily realize a constitution
in which the second pressure chamber is arranged on the
outer circumference and the third pressure chamber is
arranged on the inner circumference
Further, a fourth feature of the brake cylinder
device of the present invention is that in which a covering
is formed on the same side as the second spring relative to
the second piston to enclose an end of the rod penetrating
through the second piston, the end being arranged on the
same side as the second spring relative to the second
piston.

According to this constitution, since the covering
formed so as to enclose and cover the end of the rod
penetrating through the second piston is installed, it is
possible to effectively prevent leakage of a pressure fluid
by a simple constitution of providing the covering even in
a constitution wherein the rod penetrates through the
second piston. Further, it is not necessary to provide a
seal mechanism of a special specification for sealing a
clearance between the second piston and the rod, thus
making it possible to simplify the mechanism and reduce
costs.
Further, a fifth feature of the brake cylinder device
of the present invention is that which is provided with a
communication path for connecting communicatively the first
pressure chamber with the third pressure chamber, wherein
pressure fluid supplied to the first pressure chamber is
supplied to the third pressure chamber through the
communication path.
According to this constitution, it is possible to
easily supply to the third pressure chamber the pressure
fluid to be supplied to the first pressure chamber by a
simple constitution of providing the communication path
which communicatively connects the first pressure chamber
with the third pressure chamber.
Further, a sixth feature of the brake cylinder device

of the present invention is that which is additionally
provided with a clutch mechanism in which a supply of
pressure fluid to the second pressure chamber is stopped
and a discharge of pressure fluid from the second pressure
chamber is started, thereby giving a connection state for
connecting the rod with the second piston when the second
piston starts to move with respect to the rod by an urging
force of the second spring, and giving a non-connection
state for releasing the connection of the rod with the
second piston in a state that pressure fluid is supplied to
the second pressure chamber,wherein the communication path
is formed at the clutch mechanism which is in the non-
connection state.
According to this constitution, it is possible to
apply the brakes to a rod via a second piston by installing
a clutch mechanism which connects the rod with the second
piston when pressure fluid is discharged from the second
pressure chamber and the second piston starts to move with
respect to the rod. Then, a clearance formed in the non-
connection state of the clutch mechanism is used, by which
the thus formed clearance is allowed to function also as
the communication path to supply to the third pressure
chamber the pressure fluid to be supplied to the first
pressure chamber.
Further, a first feature of the unit brake of the

present invention is that in which a unit brake is to brake
the rotation of a wheel by allowing a brake shoe to be in
contact with the wheel of a vehicle or, specifically, the
unit brake is provided with a brake cylinder device
arranged in such a manner that the braking direction, which
is a direction in which the first piston moves, is parallel
with the shaft direction of the wheel and having at least
any one of the first feature to the sixth feature, an
adjustor installed so as to advance and retract freely in a
direction perpendicular to the braking direction inside a
brake main body and having a supporting shaft extended
perpendicularly in the advancing and retracting direction
and the braking direction, a roller installed on the
supporting shaft so as to rotate freely, a push rod
installed on the adjustor in which the brake shoe is
connected to the end portion extended from the brake main
body in the advancing direction of the adjustor; and a
wedge firmly fixed to the rod, wherein the wedge has an
inclined acting surface that is inclined in the braking
direction and capable of urging the roller in the advancing
direction when the wedge is moved in the braking direction.
According to this constitution, the first piston is
moved in the braking direction, by which the wedge firmly
fixed to the rod is also moved in the same direction. In
this instance, the inclined acting surface of the wedge is

in contact with a roller, urging the roller in the
advancing direction. Thereby, since the adjustor on which
the roller is installed is moved in the advancing direction
together with the roller, the push rod attached to the
adjustor is also moved in the advancing direction. Then,
the brake shoe installed on the leading end of the push rod
is in contact with a wheel to generate a friction, thereby
the rotation of the wheel is braked.
Since the brake cylinder device is arranged so that
the first piston moves in a direction parallel with the
shaft of the wheel, it is possible to effectively utilize a
space of the wheel in the shaft direction and also make the
space small which is necessary for installing the unit
brake in the height direction of the vehicle.
Further, since the inclined acting surface of the
wedge is used to urge the roller, it is possible to adjust
a force pushing the brake shoe to the wheel by adjusting an
angle of the inclined acting surface with respect to a
direction in which the first piston moves. For example,
where the angle is made smaller than 45°, the stroke of the
adjustor is smaller than that of the first piston, thus
making it possible to increase an urging force of the brake
cylinder device and convert the force into a force pushing
the brake shoe to the wheel.
Further, a second feature of the unit brake of the

present invention is that which is additionally provided
with a spherical bearing for providing support so that the
push rod can swing with respect to the adjustor.
According to this constitution, the brake shoe
installed on/at the leading end of the push rod is allowed
to move in a direction other than the advancing and
retracting direction of the adjustor. Thereby, it is
possible to give a greater degree of freedom to the
movement of the brake shoe and also constitute the brake
unit in such a manner that the brake shoe can be in contact
with a wheel more stably on application of the brakes.
Further, a third feature of the unit brake of the
present invention is that in which the unit brake has the
first feature or the second feature in which a male thread
is made on the outer circumferential face of the push rod
and a female thread screwed with the male thread is made on
the inner circumferential face, a cylindrical sheath rod
screwed and installed on the push rod is additionally
provided, the sheath rod is installed on the adjustor in
such a manner as to be restricted for a relative movement
toward the adjustor in the advancing and retracting
direction and also so as to make a relative movement around
the cylindrical central axis of the adjustor, and a
rotating means for rotating the sheath rod from outside the
brake main body is installed on the end portion of the

sheath rod in the retracting direction of the adjustor.
According to this constitution, the sheath rod moves
in an advancing and retracting manner in association with
the movement of the adjustor, by which the push rod screwed
and installed inside the sheath rod is allowed to move
toward the wheel in an advancing and retracting manner.
Further, since the rotating means is installed on the end
portion of the sheath rod, the push rod screwed and
installed inside the sheath rod is allowed to move toward
the sheath rod in an advancing and retracting manner by
giving a rotational force to the rotating means from
outside to rotate the sheath rod. Thereby, it is possible
to easily adjust a clearance between the brake shoe
installed on the leading end of the push rod and the wheel.
Further, a fourth feature of the unit brake of the
present invention is that in which the unit brake has at
least any one of the first feature to the third feature, or
specifically, it is additionally provided with a
ventilation hole formed on the brake main body so as to
communicatively connect the inside with the outside of the
brake main body in which a female thread is made on the
inner circumferential face, a ventilation tube formed with
a cylindrical elastic member and having at the end portion
a connection portion at which a male thread screwed with
the female thread of the ventilation hole is made and a

filter fitted inside the connection portion and made with a
material higher in rigidity than the connection portion.
According to this constitution, since the connection
portion is formed with an elastic member, it is possible to
easily fit a filter into the inner circumferential face of
the connection portion and fix the filter. Thereby, a
special member for attaching the filter can be made
unnecessary. Further, the connection portion is adjusted
for the diameter in such a manner that a force to reduce
the diameter of the connection portion is applied from the
inner circumferential face of the ventilation hole when the
connection portion is screwed into the ventilation hole in
a state that the filter is fitted into the inner
circumference face of the connection portion, thereby
making it possible to join the filter with the connection
portion more strongly.
Brief Description of the Drawings
Fig. 1 is a sectional view of a brake cylinder device
related to Embodiment 1 of the present invention.
Fig. 2 is a sectional view for explaining the
actuation of the brake cylinder device given in Fig. 1.
Fig. 3 is a sectional view for explaining the
actuation of the brake cylinder device given in Fig. 1.

Fig. 4 is a sectional view for explaining the
actuation of the brake cylinder device given in Fig. 1.
Fig. 5 is a partial sectional view of a unit brake
related to Embodiment 2.
Fig. 6 is a partial cross-sectional sagittal view
taken along S1 to S1 of the unit brake given in Fig. 5.
Fig. 7 is a partial cross-sectional sagittal view
taken along S3 to S3 of the unit brake given in Fig. 6.
Fig. 8 is a partial cross-sectional sagittal view
taken along S2 to S2 of the unit brake given in Fig. 5.
Fig. 9 is a sectional view taken along S4 to S4 in
the vicinity of an adjustable nut given in Fig. 8.
Fig. 10 is an enlarged sectional view of a
connection portion of the ventilation tube given in Fig. 5.
Fig. 11 is a plan view of a filter of the
ventilation tube.
Fig. 12 is a sectional view taken along S5 to S5 of
the filter given in Fig. 11.
Best Mode for Carrying Out the Invention
Hereinafter, a description will be given for the best
mode for carrying out the present invention by referring to
the drawings.
(Embodiment 1)

Fig. 1 is a sectional view of a brake cylinder device
1 of Embodiment 1 in the present invention. The brake
cylinder device 1 shown in Fig. 1 is provided with a normal
brake 11 actuated by pressure fluid such as compressed air
and a spring brake 12 actuated by an urging force of a
spring and composed as a brake cylinder device capable of
actuating both the normal brake 11 and the spring brake 12.
Therefore, the brake cylinder device 1 can be used, for
example, as a brake cylinder device for railway vehicles.
However, it is not limited thereto and may be used in
various applications.
As shown in Fig. 1, the brake cylinder device 1 is
composed of a cylinder main body 13, a normal brake 11 and
a spring brake 12 included in the cylinder main body 13, a
third pressure chamber 28 different from the first pressure
chamber 22 installed on the normal brake 11 and different
from the second pressure chamber 25 installed on the spring
brake 12, and a clutch mechanism 14.
The cylinder main body 13 is formed in a cylindrical
shape and provided with a first port 43 connected to a
first air supply source 101 and a second port 44 connected
to a second air supply source 102. Compressed air (pressure
fluid) supplied from the first air supply source is
supplied to the first port 43 via a normal brake control
device 103 actuating on the basis of a controller's command

(not shown). Then, the compressed air supplied to the
cylinder main body 13 from the first port 43 is discharged
via the normal brake control device 103 on the basis of a
controller's command. Further, the compressed air (pressure
fluid) supplied from the second air supply source is
supplied to the second port 44 via a spring brake control
solenoid valve 104 actuated by being switched to a
magnetized state and/or a demagnetized state on the basis
of a controller's command. Then, the compressed air
supplied to the cylinder main body 13 from the second port
44 is discharged via the spring brake control solenoid
valve 104 on the basis of a controller's command.
The normal brake 11 is composed of a rod 21, a first
pressure chamber 22, a first spring 23 and a first piston
24. The rod 21 is formed so as to project from the first
piston 24 disposed inside a cylinder main body 13. The
leading end 21a of the rod 21 is disposed so as to project
from the cylinder main body 13, and connected, for example,
to a brake shoe (not shown) which generates a braking force
resulting from a friction force to reduce the rotation of a
wheel by being pressed against the tread in contact with a
rail on the wheels of a carriage of a railway vehicle. Then,
the leading end 21a of the rod 21 moves in a direction
projected from the cylinder main body 13 (the direction
indicated by the arrow (A) in the drawing), by which a

brake shoe is urged to actuate the brake. The first
pressure chamber 22 is connected to the first port 43 and
formed by being sectioned by the first piston 24 inside the
cylinder main body 13. The first spring 23 is disposed at
an area sectioned by the first piston 24 on one end inside
the cylinder main body 13 and arranged so as to oppose the
first pressure chamber 22 via the first piston 24. The
first piston 24 is disposed so as to reciprocate freely
inside the cylinder main body 13 (sliding freely on the
inner wall of the cylinder main body 13), moving against an
urging force resulting from the elastic recovery of the
compressed first spring 23 by the compressed air supplied
to the first pressure chamber 22 from the first port 43.
Therefore, the normal brake 11 is provided with the first
piston 24 in which the first pressure chamber 22 and the
first spring 23 act so as to oppose each other, with the
rod 21 projecting, wherein compressed air is supplied to
the first pressure chamber 22, thereby the first piston 24
moves in a braking direction (the direction indicated by
the arrow (A) in the drawing) against an urging force of
the first spring 23.
The spring brake 12 is composed of a second pressure
chamber 25, a second spring 26 and a second piston 27. The
second pressure chamber 25 is communicatively connected to
a second port 44 and formed inside the cylinder main body

13 by being divided by the second piston 27. The second
spring 26 is disposed at an area divided by the second
piston 27 on the other end inside the cylinder main body 13
and arranged so as to oppose the second pressure chamber 25
via the second piston 27. The second piston 27 is disposed
so as to reciprocate freely inside the cylinder main body
13 (sliding freely on the inner wall of the cylinder main
body 13), provided so as to move in a direction axially of
the rod 21 and also formed in such a manner that the rod 21
penetrates therethrough. Then, compressed air is supplied
to the second pressure chamber 25 from the second port 44,
by which the second piston 27 moves in an anti-braking
direction, specifically a direction reverse to the above-
described braking direction against an urging force
resulting from the elastic recovery of the compressed
second spring 26. On the other hand, the compressed air
supplied inside the second pressure chamber 25 is
discharged through the second port 44, by which the second
piston 27 moves in the braking direction by an urging force
of the second spring 26. Since the spring brake 12 is
provided with the second piston 27 in which the second
pressure chamber 25 and the second spring 26 act so as to
oppose each other, a state that the compressed air is
supplied to the second pressure chamber 25 is shifted to a
state that it is discharged, thus the second piston 27

moves in the braking direction by an urging force of the
second spring 26.
The third pressure chamber 28 is arranged so as to
oppose the second spring 26 via the second piston 27 and
also arranged so as to act as a pressure chamber divided
and sectioned from the second pressure chamber 25 with
respect to the second piston 27. Then, compressed air
supplied to the first pressure chamber 22 is supplied to
the third pressure chamber 28 via a communication path 45
formed at a clutch mechanism 14 to be described later,
thereby the second piston 27 moves in the above-described
braking direction against an urging force of the second .
spring 26. Further, a cylindrical wall 29 formed in a
cylindrical shape, which is disposed along the
circumferential direction and projected in the braking
direction, is installed on the second piston 27. Therefore,
the cylindrical wall 29 is slidingly in contact with an
inner cylindrical portion 30 formed in a cylindrical shape
along the circumferential direction inside the cylinder
main body 13, and the cylindrical wall 29 sections the
second pressure chamber 25 and the third pressure chamber
28. Therefore, the second pressure chamber 25 is arranged
along the circumferential direction on the outer
circumference of the second piston 27, and the third
pressure chamber 28 is arranged along the circumferential

direction on the inner circumference of the second piston
27.
The clutch mechanism 14 is provided as a mechanism in
which a state that compressed air is supplied to the second
pressure chamber 25 is shifted to a state that it is
discharged, thereby giving a connection state for
connecting the rod 21 with the second piston 27 when the
second piston 27 starts to move with respect to the rod 21
by an urging force of the second spring 26, and giving a
non-connection state for releasing the connection of the
rod 21 with the second piston 27 in a state that compressed
air is supplied to the second pressure chamber 25.
The clutch mechanism 14 is composed of a screw 32, a
nut member 33 and a rotation stopping means 34. The screw
32 is formed on the outer circumference of an end portion
which is opposite the leading end 21a of the rod 21. The
nut member 33 is arranged in meshing with the screw 32 and
supported by the second piston 27 so as to rotate freely
via a shaft bush 42. Thereby, the nut member 33 is screwed
with the screw 32 and also rotated by a relative movement
of the rod 21 and the second piston 27.
The rotation stopping means 34 is installed as means
for stopping the rotation of the nut member 33 in contact
with the nut member 33 when the second piston 27 starts to
move relatively with respect to the rod 21, and is composed

of a sleeve member 35 opposing the nut member 33 and a
meshing means 36 installed on a part where the nut member
33 is opposed to the sleeve member 35. The sleeve member 35
is inserted axially along the inner cylindrical portion 30
so as to slide freely. Then, the sleeve member 35 is urged
by a spring 37 toward a stopper ring 38. The sleeve member
35 is to be stopped for rotation in one direction by a lock
lever 40. Specifically, a latch blade 39 extended axially
is installed on the outer circumference of the sleeve
member 35, and a blade edge 41 urged by a spring 46 toward
the latch blade 39 is installed on the leading end of the
lock lever 40. The latch blade 39 and the blade edge 41 act
as a one-way clutch which prevents the rotation together
with the rotation in association with the movement of the
nut member 33 toward one side (braking direction) and
permits the rotation together with the rotation of the nut
member 33 toward the other side (anti-braking direction).
It is noted that the blade edge 41 of the lock lever 40 is
urged toward the latch blade 39 by the spring 46 and
removed from the latch blade 39 against an urging force of
the spring 46 when the lock lever 40 is pulled up. The
latch blade 39 of the sleeve member 35 is extended axially
and the blade edge 41 of the lock lever 40 is engaged with
one side of the latch blade 39, by which the latch blade 39
can be continuously engaged with the blade edge 41, even if

the sleeve member 35 slides toward one side.
In the rotation stopping means 34, the meshing means
36 is composed of a indented blade 36a formed on the end
portion of the nut member 33 opposing the sleeve member 35
and an indented blade 36b formed on the end portion of the
sleeve member 35 opposing the nut member 33. When the
second piston 27 starts to move with respect to the rod 21,
the indented blade 36a of the nut member 33 is meshed with
the indented blade 36b of the sleeve member 35, and the nut
member 33 is stopped for rotation to give a connection
state for connecting the rod 21 with the second piston 27.
On the other hand, in a state that compressed air is
supplied to the second pressure chamber 25, the indented
blade 36a of the nut member 33 is not meshed with the
indented blade 36b of the sleeve member 35. Therefore, the
nut member 33 is in a state of rotating freely to give a
non-connection state for releasing the connection of the
rod 21 with the second piston 27.
Further, when the clutch mechanism 14 is in the
above-described non-connection state, a communication path
45 is to be formed, which communicatively connects the
first pressure chamber 22 with the third pressure chamber
28. In other words, when the clutch mechanism 14 is in the
non-connection state in which the indented blade 36a of the
nut member 33 is not meshed with the indented blade 36b of

the sleeve member 35, the communication path 45 is formed
at a clearance between the indented blade 36a and the
indented blade 36b. Then, compressed air supplied to the
first pressure chamber 22 via the communication path 45 is
to be supplied to the third pressure chamber 28.
Further, a covering 31 is installed in the brake
cylinder device 1. The covering 31 is formed on the same
side as the second spring 26 relative to the second piston
27 to enclose an end portion 21b of the rod 21 penetrating
through the second piston 27.The end portion 21b is
arranged on the same side as the second spring 26 relative
to the second piston 27.Then, the covering 31 is formed
into a cylindrical shape, for example, and disposed so as
to pass through the inside of the second spring 26 and
penetrate through a hole portion formed on the end portion
of the cylinder main body 13, thereby projecting outside
the cylinder main body 13. Since the covering 31 moves
together with the second piston 27, it is possible to
easily recognize visually an operation state of the second
piston 27, specifically, a state that the spring brake 12
is in operation, from outside the cylinder main body 13.
Next, a description will be given for actuation of
the brake cylinder device 1. Fig. 1 is a sectional view of
the brake cylinder device 1 which is in a slackened state
that neither of the normal brake 11 or the spring brake 12

operates. For example, when braking operation is not
performed in driving a railway vehicle, the state will be
as shown in Fig. 1. in this state, no compressed air is
supplied to the first pressure chamber 22 from a first air
supply source 101 via a normal brake control device 103 and
a first port 43 on the basis of the control by the normal
brake control device 103. Then, compressed air inside the
first pressure chamber 22 is spontaneously discharged via
the normal brake control device 103 and the first port 43.
Therefore, inside the cylinder main body 13, the first
piston 24 is urged by the first spring 23 in an anti-
braking direction (the direction indicated by the arrow (B)
in the drawing), and the first piston 24 is in contact with
the end portion 30a of the inner cylindrical portion 30.
On the other hand, in the state shown in Fig. 1,
compressed air is supplied to the second pressure chamber
25 from the second air supply source 102 via the spring
brake control solenoid valve 104 and the second port 44 on
the basis of the control by the spring brake control
solenoid valve 104. Therefore, the second piston 27 is in a
state that it has moved in an anti-braking direction (the
direction indicated by the arrow (B) in the drawing)
against an urging force of the second spring 26 due to an
urging force resulting from the action of the compressed
air supplied to the second pressure chamber 25. In this

state, the indented blade 36a of the nut member 33 is not
meshed with the indented blade 36b of the sleeve member 35
to give a clearance.
Fig. 2 is a sectional view of the brake cylinder
device 1 showing a state that both the normal brake 11 and
the spring brake 12 are in a slackened state shown in Fig.
1 shifted to a state that the normal brake 11 is actuated.
Compressed air is supplied to the first pressure chamber 22
from the first air supply source 101 via the first port 43
on the basis of the control by the normal brake control
device 103, by which the normal brake 11 is actuated. In
this instance, as shown in Fig. 2, the first piston 24
moves in the braking direction (the direction indicated by
the arrow (A) in the drawing) against an urging force of
the first spring 23 due to an urging force resulting from
the action of the compressed air supplied to the first
pressure chamber 22. Thereby, the rod 21 is moved in the
braking direction together with the first piston 24, and a
brake shoe (not shown) connected to the leading end 21a
thereof is pressed against the wheel tread, thereby
generating a braking force. It is noted that a screw 32
installed on the rod 21 is screwed with the nut member 33,
but when the rod 21 moves in the braking direction together
with the first piston 24, the nut member 33 is supported by
the shaft bush 42 so as to rotate freely with respect to

the second piston 27. Therefore, the nut member 33 is
rotated together with the movement of the rod 21 in the
braking direction, while it is supported by the shaft bush
42, thus resulting in movement of the rod 21 alone in the
braking direction.
Further, in the state as shown in Fig. 2, the
indented blade 36a of the nut member 33 is not meshed with
the indented blade 36b of the sleeve member 35 to form a
clearance, which forms the communication path 45 formed by
thus state. Therefore, compressed air supplied to the first
pressure chamber 22 is to be supplied to the third pressure
chamber 28 as well via the communication path 45. Thereby,
even if there is developed a state that no compressed air
is supplied to the second pressure chamber 25 from the
second air supply source 102 while the normal brake is in
operation due to malfunction of the spring brake control
solenoid valve 104 or others, the compressed air to be
supplied to the first pressure chamber 22 is to act on the
third pressure chamber 28 via the communication path 45
with respect to the second piston 27. Therefore, such a
state can be kept that the second piston 27 is urged and
moved in the anti-braking direction against an urging force
of the second spring 26 when the normal brake 11 is in
operation. It is, thereby, possible to prevent an excessive
braking actuation of both the normal brake force and the

spring brake force resulting from a simultaneous operation
of the normal brake 11 and the spring brake.
Fig. 3 is a sectional view of a spring brake cylinder
1 which shows a state that the spring brake 12 is actuated.
Where the spring brake 12 is actuated, for example, the
normal brake 11 is actuated (refer to Fig. 2) and used as a
parking brake in a completely stopped state of a railway
vehicle, thus resulting in actuation of the spring brake 12.
The spring brake 12 is actuated by compressed air
discharged from the second pressure chamber 25 via the
second port 44 and the spring brake control solenoid valve
104 on the basis of the control of the spring brake control
solenoid valve 104. It is noted that when the spring brake
12 is actuated, the compressed air from the first air
supply source 101 is not supplied to the first pressure
chamber 22 but the compressed air inside the first pressure
chamber 22 is spontaneously discharged via the first port
43 and the normal brake control device 103.
When the compressed air supplied inside the second
pressure chamber 25 is discharged via the second port 44
and the spring brake control solenoid valve 104, the second
piston 27 starts to move in a braking direction (the
direction indicated by the arrow (A) in the drawing) by an
urging force of the second spring 26. In this instance, the
nut member 33 is rotated around the screw 32 of the rod 21,

by which the second piston 27 starts to move in the braking
direction, together with the nut member 33, with respect to
the rod 21. Then, as described above, when the second
piston 27 starts to move with respect to the rod 21, the
nut member 33 is in contact with the sleeve member 35. In
other words, the meshing means 36 is in a state that the
indented blade 36a of the nut member 33 is meshed with the
indented blade 36b of the sleeve member 35. It is noted
that in this instance, the communication path 45 (refer to
Fig. 2) is closed. When the meshing means 36 is meshed
therewith, the latch blade 39 of the sleeve member 35 is
engaged with the blade edge 41 of the lock lever 40,
thereby preventing the rotation together with the rotation
in association with the movement of the sleeve member 35 in
the braking direction. As a result, the rotation of the nut
member 33 is stopped by the rotation stopping means 34. It
is noted that when the meshing means 36 is meshed therewith,
the nut member 33 and the sleeve member 35 make a slight
movement in the braking direction together with the second
piston 27 against an urging force of the spring 37 but the
latch blade 39 of the sleeve member 35 is engaged with the
blade edge 41 of the lock lever 40 deeply in an axial
direction to result in a halt of the second piston 27, the
nut member 33 and the sleeve member 35.
The meshing means 36 is meshed as described above, by

which the clutch mechanism 14 is to move from a non-
connection state to a connection state. Then, in the
connection state shown in Fig. 3, since the rotation of the
nut member 33 is stopped by the rotation stopping means 34,
the second piston 27 urges the rod 21 via the nut member 33
by an urging force of the second spring 26 in a state that
it has moved in the braking direction and consequently the
rod 21 is kept moved in the braking direction. In other
words, such a state is retained that the spring brake 12 is
actuated to apply a spring brake force. It is noted that
even if a reaction force resulting from the brake shoe (not
shown) of the wheel tread acts on the rod 21 in an anti-
braking direction, there is developed a state that screw
threads are pressed against each other between the nut
member 33 and the screw 32, and consequently the rod 21 is
kept at a position where the brakes are applied.
Fig. 4 is a sectional view of the brake cylinder
device 1 for explaining a case where a spring brake force
is manually released from a state that the spring brake 12
is in operation. Where the spring brake force is desired to
be released, for example, a case where a railway vehicle is
desired to be parked after a slight movement not by
actuating an air compressor but by using a tractor, it is
possible to release the spring brake force by operating the
lock lever 40. In this case, when the lock lever 40 is

manually pulled up to the direction indicated by the arrow
(C) in the drawing, the blade edge 41 of the lock lever 40
is removed from the latch blade 39 of the sleeve member 35,
the meshing means 36 between the nut member 33 and the
sleeve member 35 becomes rotatable, while kept in meshed
state, and consequently the clutch mechanism 14 rotates
without load as a whole- Thereby, both the first piston 24
and the second piston 27 are able to move up to the stroke
end due to an urging force of the first spring 23 and the
second spring 26 to result in movement of the first piston
24 and the rod 21 in an anti-braking direction. As
described above, it is possible to release manually the
spring brake force of the spring brake 12 by operating the
lock lever 40 and move railway vehicles or the like.
As described above, according to the brake cylinder
device 1, compressed air to be supplied to the first
pressure chamber 22 is supplied to the third pressure
chamber 28, by which the third pressure chamber 28 allowing
the second piston 27 to be moved in an anti-braking
direction against an urging force of the second spring 26
acts on the second piston 27 as a pressure chamber divided
and sectioned from the second pressure chamber 25.
Therefore, when the normal brake 11 is in operation, the
third pressure chamber 28 acts so that the second piston 27
moves in an anti-braking direction, thus making it possible

to prevent a simultaneous operation of the normal brake 11
and the spring brake 12. Further, such a simple mechanism
with the third pressure chamber for supplying compressed
air supplied to the first pressure chamber 22 without the
necessity for a double check valve which may often result
in complicated piping, increases the number of components
or maintenance load, thus making it possible to prevent a
simultaneous operation of the normal brake and the spring
brake. As a result, the mechanism can be made simple to
greatly reduce costs.
Therefore, the brake cylinder device 1 is not only
able to omit the double check valve but also able to
prevent a simultaneous operation of the normal brake 11 and
the spring brake 12 by using a simple mechanism.
Further, according to the brake cylinder device 1,
since the second pressure chamber 25 and the third pressure
chamber 28 are arranged respectively on the outer
circumference of the second piston 27 and on the inner
circumference thereof in the circumferential direction, the
second piston 27 can be uniformly urged in an axially
symmetrical manner against an urging force of the second
spring 26 even upon actuation of either the second pressure
chamber 25 or the third pressure chamber 28. Therefore, it
is possible to realize a mechanism for uniformly urging the
second piston 27 by a simple constitution in which the

second pressure chamber 25 is arranged on the outer
circumference and the third pressure chamber 28 is arranged
on the inner circumference. Further, it is not necessary to
install an additional mechanism for uniformly urging the
second piston 27, thus making the mechanism simple to
reduce costs.
Further, according to the brake cylinder device 1, a
simple mechanism is provided in which the cylindrical wall
29 slidingly in contact with the inner cylindrical portion
30 formed inside the cylinder main body 13 is installed on
the second piston 27 to section the second pressure chamber
25 and the third pressure chamber 28, thus making it
possible to easily realize a constitution in which the
second pressure chamber 25 is arranged on the outer
circumference and the third pressure chamber 28 is arranged
on the inner circumference.
Further, according to the brake cylinder device 1. a
covering 31 is formed on the same side as the second spring
26 relative to the second piston 27 to enclose an end
portion 21b of the rod 21 penetrating through the second
piston 27. the end portion 21b is arranged on the same side
as the second spring 26 relative to the second piston
27.Therefore, even in a constitution in which the rod 21
penetrates through the second piston 27, a simple
constitution equipped with the covering 31 is used to

effectively prevent the leakage of compressed air without
providing a special seal mechanism at a shaft bush 42 or at
a clearance between the second piston 27 and the rod 21,
thus making the mechanism simple to reduce costs. Further,
since the inside of the covering 31 is communicatively
connected to the third pressure chamber 28 via the shaft
bush 42 or a clearance between the second piston 27 and the
rod 21, pressure fluid supplied to the third pressure
chamber 28 is supplied inside the covering 31. In other
words, since the inside thereof acts as an extended part of
the third pressure chamber 28, a projected area of this
part corresponding to the second piston 27 is changed, thus
making it possible to easily adjust the balance between a
force generated by pressure of the pressure fluid, a force
generated by the second spring 26, a force generated by the
second pressure chamber 25 and a force generated by the
third pressure chamber 28.
Further, according to the brake cylinder device 1, it
is possible to easily supply to the third pressure chamber
28 compressed air to be supplied to the first pressure
chamber 22 by a simple mechanism which has a communication
path 45 communicatively connecting the first pressure
chamber 22 with the third pressure chamber 28.
Further, according to the brake cylinder device 1, a
clutch mechanism 14 is provided which connects the rod 21

and the second piston 27 when the second piston 27 starts
to move with respect to the rod 21 upon discharge of
compressed air from the second pressure chamber 25, thereby
making it possible to apply a spring brake force to the rod
21 via the second piston 27. Therefore, a clearance formed
on the clutch mechanism 14 in a non-connection state is
utilized, thereby allowing a clearance formed on the clutch
mechanism 14 in the non-connection state to function also
as the communication path 45 for supplying compressed air
to be supplied to the first pressure chamber 22 to the
third pressure chamber 28.
(Embodiment 2)
Next, a description will be given for a unit brake of
Embodiment 2 in the present invention. Fig. 5 is a partial
sectional view of a wheel 201 in the shaft direction when
the wheel is attached to a unit brake 100 of Embodiment 2.
Fig. 6 is a partial cross-sectional sagittal view taken
along S1 to S1 in Fig. 5. Fig. 7 is a partial cross-
sectional sagittal view taken along S3 to S3 in Fig. 6. Fig.
8 is a partial cross-sectional sagittal view taken along S2
to S2 in Fig. 5. It is noted that the unit brake of
Embodiment 2 is provided with a brake cylinder device 1'
having major parts of the brake cylinder device 1 explained
in Embodiment 1, and members which are the same as those
explained for Embodiment 1 in Fig. 5 to Fig. 8 will be

given the same symbols and omitted for explanation.
As shown in Fig. 5, the unit brake 100 is a unit
brake in which the braking face 202a of the brake shoe 202
is allowed to come into contact with the tread 210a of the
wheel 201 of a vehicle, thereby friction is used to brake
the rotation of the wheel 201.
The unit brake 100 is provided with a brake main body
70 formed in a box shaped so as to partially cover a
driving mechanism of brake and a push rod 71 projecting
toward a wheel from the inside of the brake main body 70. A
supporting arm 72 extending above the wheel is fixed to the
brake main body 70. A hanger 73 is supported at the end
portion of the supporting arm 72 via a pin 72a so as to
sway freely.
The brake shoe 202 is supported so as to rotate via a
pin 71a with respect to the lower end portion of the hanger
73 and the leading end of the push rod 71.
As shown in a partial cross section cut in a cross
section parallel with the shaft in Fig. 6 (a partial cross-
sectional sagittal view taken along S1 to S1), in the unit
brake 100, the brake cylinder device 1' is arranged in such
a manner that a direction in which the first piston 64
moves (the braking direction A indicated by the arrow (A)
in Fig. 5 to Fig. 8 and the anti-braking direction B
indicated by the arrow (B)) is parallel with the shaft.

The normal brake 60 of the brake cylinder device 1'
is composed of a rod 61, a first pressure chamber 62, a
first spring 63, and a first piston 64. The end portion of
the rod 61 in the braking direction A is fixed to the first
piston 64 disposed inside the cylinder main body 13.A wedge
65 projecting so as to taper in the braking direction A is
fixed to the first piston 64. It is noted that a pair of
the wedges 65 are formed approximately in a symmetrical
manner behind the push rod 71.
Further, an adjustor 80 is provided inside the brake
main body 70, which is composed so as to advance into or
retract from the wheel 201 in an advancing direction X (the
direction indicated by the arrow (X) in Fig. 5, Fig. 6 and
Fig. 7) or in a reverse direction, specifically, a
retracting direction Y (the direction indicated by the
arrow (Y) in Fig. 5, Fig. 6 and Fig. 7). The adjustor 80 is
composed of a cylindrical sleeve portion 81 extending
parallel with the advancing direction, a first supporting
shaft 82 (supporting shaft) extending perpendicularly to an
axial direction of the sleeve portion 81 from both the side
faces of the sleeve portion 81 and a rectangular slide
plate 83 fitted into the first supporting shaft 82. Further,
a first roller 84 (roller) is arranged on the first
supporting shaft 82 so as to rotate freely.
The brake main body 70 is provided with a guide

portion 75 having a guide face75a extending in the
advancing and retracting direction so as to be orthogonal
to the braking direction A and also projecting partially
from the inner face of the brake main body 70.
The adjustor 80 is attached to the brake main body 70
so that the first supporting shaft 82 is made perpendicular
to the braking direction A, and arranged so that the edge
face 83a of the slide plate 83 in the braking direction A
is able to slide in contact with the guide face 75a of the
guide portion 75 (refer to Pig. 8).
As shown in Fig. 7, a sheath rod 85 is installed
inside the sleeve portion 81 of the adjustor 80. The sheath
rod 85 is supported via a spherical bearing 86 made up of a
spherical member 86a installed on the outer circumference
of the sheath rod 85 with respect to the sleeve inner
circumferential face 81a and a shaft bush portion 86b
installed with respect to the sleeve inner circumferential
face 81a, and restricted for movement relative to the
sleeve portion 81 in an advancing and retracting direction.
Thereby, the sheath rod 85 is composed so as to advance or
retract in association with an advancing and retracting
movement of the adjustor 80.
The sheath rod 85 is a tubular member extending
linearly,and a female thread is made substantially all over
the inner circumferential face in a longitudinal

direction.lt is noted that the sheath rod 85 is supported
by the sleeve portion 81 via the spherical bearing 86 so as
to sway within a predetermined angle with respect to the
cylindrical central axis C1 of the sleeve portion 81
(indicated by the single dotted and dashed line in Fig.
7)and also rotate around the cylindrical central axis.
A male thread is made on the push rod 71, which is
screwed with the female thread of the sheath rod 85 on the
outer circumferential face in the vicinity of the end
portion opposite one end to which the brake shoe 202 is
fitted. It is noted that the length of a portion at which
the male thread is made is made approximately equal to the
length of the sheath rod 85. Then, the push rod 71 is
installed in such a state that the end portion at which the
male thread is made is screwed into the sheath rod 85.
Thereby, the push rod 71 is able to advance or retract in
association with an advancing and retracting movement of
the sheath rod 85, thus making it possible to press the
brake shoe 202 installed on the leading end against the
tread 201a of the wheel 201 and release it from the tread
201a.
Further, the brake main body 70 is provided with a
second supporting shaft 76 extending perpendicularly with
respect to the advancing and retracting direction of the
adjustor 80 and also the braking direction A in the

vicinity of the end portion opposite the wheel. A second
roller 77 is supported by the second supporting shaft 76 so
as to rotate.
It is noted that the first rollers 84 and the slide
plate 83 are installed symmetrically in pairs with respect
to the adjustor 80 behind sleeve portion 81 and the second
rollers 77 are also installed in pairs with respect to the
second supporting shaft 76 so as to oppose a pair of the
first rollers 84, 84. Further, guide portions 75 are formed
in pairs on the brake main body 70 so as to oppose a
position at which a pair of the slide plates 83, 83 are
installed.
A wedge 65 installed on the rod leading end of the
brake cylinder device 1' is fixed to the rod 61 via the
first piston 64 in such a manner that the end portion is
inserted between the first roller 84 and the second roller
77. Then, the wedge 65 is provided with a reaction face 65b
in contact with the second roller 77 and extending in a
direction parallel to the first piston 64 and an inclined
acting surface 65a which is inclined so as to come closer
to the reaction face 65b moving toward the end portion
opposite the first piston 84 also in contact with the first
roller 64. In other words, the inclined acting surface 65a
is an actuation face which is inclined so as to move down
in a retracting direction of the adjustor 80 toward the

braking direction A.
Next, a description will be given for the motion of
the brake unit.
First, where the brakes are applied, on the basis of
instructions from a controller (not shown), compressed air
is supplied to the first pressure chamber 62 via the first
port 43, thereby the first piston 64 is moved in the
braking direction A (refer to Fig. 6). In this instance,
the wedge 65 is moved in the braking direction A in
association with the movement of the first piston 64.
Upon movement of the wedge 65 in the braking
direction A, the reaction face 65b is moved in the braking,
direction A, while being in contact with the second roller
77, and the inclined acting surface 65a inclined to the
reaction face 65b is moved in the braking direction A,
while urging the first roller 84 installed on the adjustor
80. In this instance, an urging force having at least a
component X in an advancing direction X acts on the first
roller 84 from the inclined acting surface 65a. Since the
adjustor 80 is restricted for movement in the braking
direction A by the guide face 75a, the adjustor 80 is moved
in the advancing direction X against an urging force of the
spring 88, while allowing the slide plate 83 to be in
contact with the guide face 75a. In association with this
movement, a push rod 71 (refer to Fig. 7) connected to the

sleeve portion 81 via the spherical bearing 86 and the
sheath rod 85 is also moved in the advancing direction X.
Thereby, a brake shoe 202 installed on the push rod 71 is
pressed against a wheel 201, thereby braking the rotation
of the wheel 201.
On the other hand, where the brakes are relaxed,
compressed air is discharged from the first pressure
chamber 62 via the first port 43 on the basis of
instructions from a controller (not shown), and the first
piston 64 is moved in an anti- braking direction B.In this
instance, the wedge 65 is to be moved in the anti-braking
direction B in association with the movement of the first
piston 64.
Since the adjustor 80 is pressed in a retracting
direction Y by an urging force of the spring 88, the first
roller 84 in contact with the inclined acting surface 65a
is moved in the retracting direction Y upon movement of the
wedge 65 in the anti-braking direction B. In association
with movement of the adjustor 80 in the retracting
direction Y, the push rod 71 is also moved in the
retracting direction Y. Thereby, the brake shoe 202
installed on the push rod 71 is also moved in the
retracting direction Y and removed from a wheel 201 to
release the brake of the wheel 201.
It is noted that since the brake shoe 202 is

connected to a hanger 73 (refer to Fig. 5). it makes a
circular movement at the center of the base end of the
hanger 73. However, since the push rod 71 is connected to
the adjustor 80 via the spherical bearing 86 (refer to Fig.
7), the circular movement is allowed at the leading end of
the push rod 71.
As described above, the unit brake 100 of Embodiment
2 is that in which the brake shoe 202 is allowed to be in
contact with the wheel 201 of a vehicle, thereby braking
the rotation of the wheel 201.
Therefore, provided is a brake cylinder device 1'
arranged so that the braking direction A, specifically, a
direction in which the first piston 64 moves, is parallel
with the shaft direction of the wheel 201, an adjustor 80
installed inside the brake main body 70 so as to advance or
retract freely in a direction perpendicular to the braking
direction A (the advancing direction X or the retracting
direction Y) and equipped with a first supporting shaft 82
extending perpendicularly to the advancing and retracting
direction (the advancing direction X or the retracting
direction Y) and the braking direction A, a first roller 84
installed on the first supporting shaft 82 so as to rotate
freely, a push rod 71 installed on the adjustor 80 in which
the brake shoe 202 is connected to the end portion
extending from the brake main body 70 in the advancing

direction X of the adjustor 80 and a wedge 65 firmly fixed
to the rod 61.
The wedge 65 is provided with an inclined acting
surface 65a which is inclined in the braking direction A
and able to urge the first roller 84 toward the advancing
direction X when moved in the braking direction A.
According to this constitution, the first piston 64
is moved in the braking direction A, by which the wedge 65
firmly fixed to the rod 61 is also moved in the same
direction. In this instance, the inclined acting surface
65a of the wedge 65 is in contact with the first roller 84,
urging the first roller 84 in the advancing direction.
Thereby, the adjustor 80 on which the first roller 84 is
installed is moved in the advancing direction together with
the first roller 84, and the push rod 71 attached to the
adjustor 80 is also moved in the advancing direction. Then,
the brake shoe 202 installed on the leading end of the push
rod 71 is in contact with the wheel 201 to brake the
rotation of the wheel 201 due to friction.
The brake cylinder device 1' is arranged in such a
manner that a direction in which the first piston 64 moves
is parallel with the shaft of the wheel 201, thus making it
possible to effectively use a space in an axial direction
of the shaft and also make small the space necessary for
installing the unit brake 100 in a height direction of the

vehicle.
Further, since the brake cylinder device is composed
so as to urge the first roller 84 by the inclined acting
surface 65a of the wedge 65, the inclined acting surface
65a is adjusted for the angle with respect to a direction
in which the first piston 64 moves, thereby making it
possible to adjust a force by which the brake shoe 202 is
pressed against the wheel 201. For example, where this
angle is made smaller than 4° , the adjustor 80 is made
smaller in stroke than the first piston 64, thereby making
it possible to increase an urging force of the brake
cylinder device 1' and convert the urging force into a
force by which the brake shoe 202 is pressed against the
wheel 201.
Further, since the push rod 71 is supported so as to
swing via the spherical bearing 86 with respect to the
adjustor 80, the brake shoe 202 installed on the leading
end of the push rod 71 is allowed for movements of the
adjustor 80 other than those in the advancing and
retracting direction. Thereby, it is possible to give a
greater degree of freedom to movements of the brake shoe
202 and also provide a constitution so that the brake shoe
202 is in contact with the wheel 201 more stably when the
brakes are applied.
Next, a description will be given for a position

adjusting mechanism of the brake shoe installed on the unit
brake 100.
As shown in Fig. 7. an adjustable nut 90 (rotating
means) for relatively rotating the sheath rod 85 with
respect to the push rod 71 is installed on the end portion
of the sheath rod 85 in the retracting direction Y. Fig. 9
is a sectional view taken along S4 to S4 in the vicinity of
the adjustable nut 90 in Fig. 7.
The adjustable nut 90 is composed of a pin 91
inserted into a through hole penetrating diametrically at
the end portion of the sheath rod 85, an engaging member 92
which can be engaged with the pin 91 in a direction in
which the sheath rod 85 rotates at the center of the shaft,
a pin 93 penetrating diametrically through the engaging
member 92, a nut portion 94 arranged so as to cover the
engaging member 92, with the one end opened, in which both
ends of the pin 93 are penetrated to be installed on a
circumferential wall, and a spring 95 installed between the
nut portion 94 and the engaging member 92.
The nut portion 94 is installed rotatably on the
brake main body 70 in such a manner that the end portion of
the push rod 71 on the brake main body 70 in the retracting
direction Y covers the opening portion 70a formed on an
opposing circumferential wall. It is possible to rotate the
engaging member 92 via the pin 93 by rotation of the nut

portion 94.
Further, a through hole through which the pin 93 of
the engaging member 92 penetrates is formed as a long hole
extending in the advancing and retracting direction.
Therefore, the engaging member 92 is able to move
relatively in the advancing and retracting direction with
respect to the pin 93 fixed to the nut portion 94. Still
further, the engaging member 92 is provided at the. end
portion opposing the push rod 71 with an engagement groove
92a extending diametrically and having such a width and a
depth that can be engaged with the pin 91 (refer to Pig. 9).
According to the constitution of the above adjustable
nut 90, where the direction of the pin 91 installed on the
rear end of the sheath rod 85 is in agreement with that of
the engagement groove 92a of the engaging member 92 upon
retraction of the sheath rod 85 in the retracting direction
Y, the pin 91 is engaged with the engagement groove 92a. On
the other hand, where the direction of the pin 91 is
different from that of the engagement groove 92a, the
engaging member 92 moves inside the nut portion 94 in the
retracting direction Y against an urging force of the
spring 95 due to a fact that the end portion of the
engaging member 92 is urged by the pin 91. Therefore, there
is no chance that the adjustable nut 90 prevents such a
motion that the sheath rod 85 moves in the retracting

direction Y.
Even where the direction of the pin 91 is not in
agreement with that of the engagement groove 92a and the
engaging member 92 moves in the retracting direction Y
against an urging force of the spring 95, the nut portion
94 is rotated from outside, thereby the engaging member 92
is rotated up to a position at which the direction of the
engagement groove 92a is in agreement with that of the pin
91. Then, the engaging member 92 moves in the advancing
direction X due to an urging force of the spring 95 and the
engagement groove 92a is consequently engaged with the pin
91.
In a state that the pin 91 is engaged with the
engaging member 92, the nut portion 94 is rotated from
outside, by which the sheath rod 85 can be rotated via the
pin 93, the engaging member 92 and the pin 91. In a state
that the push rod 71 is restricted for rotation, the sheath
rod 85 is rotated, by which the push rod 71 is allowed to
advance and retract with respect to the sheath rod 85 due
to the screw action. It is, thus, possible to adjust an
extent of projection from the brake main body 70,
specifically, to adjust a position of the brake shoe 202.
As described above, the unit brake 100 of Embodiment
2 is provided with a push rod 71 in which a male thread is
made on the outer circumferential face thereof. The unit

brake 100 is additionally provided with a cylindrical
sheath rod 85a screwed and installed on the push rod 71 in
which a female thread screwed with the male thread is made
on the inner circumferential face and a spherical bearing
86 for providing support by connecting the sheath rod 85
with the adjustor 80 in such a manner that the sheath rod
85 is restricted for relative movement with respect to the
adjustor 80 in the advancing and retracting direction, the
sheath rod 85 can sway with respect to the adjustor 80 and
also the sheath rod 85 can rotate around the cylindrical
central axis with respect to the adjustor 80. Further, an
adjustable nut 90 for rotating the sheath rod 85 from
outside the brake main body 70 is installed on the end
portion of the sheath rod 85 in the retracting direction of
the adjustor 80.
According to this constitution, since the sheath rod
85 is supported by the adjustor 80 via the spherical
bearing 86,it is able to rotate relatively around the
cylindrical axis with respect to the adjustor 80. Then,
since the adjustable nut 90 is installed on the end portion,
the sheath rod 85 is rotated by applying a rotational force
to the nut portion 94 of the adjustable nut 90 from outside,
thereby the push rod 71 screwed into the sheath rod 85 is
allowed to advance and retract. As a result, it is possible
to easily adjust a clearance between the brake shoe 202

installed on the leading end of the push rod 71 and the
wheel 201. Further, since the sheath rod 85 is supported so
as to sway with respect to the adjustor 80 via the
spherical bearing 86, it is possible to give a greater
degree of freedom to motions of the brake shoe 202
installed on the leading end of the push rod 71.
Then, a description will be given for a ventilation
channel formed on the unit brake 100.
As shown in Fig. 5, a ventilation hole 70b is formed
on the brake main body 70 below a position at which the
push rod 71 is extended. A female thread is made on the
inner circumferential face of the ventilation hole 70b.
Then, a ventilation tube 97, which is a tubular member
formed with an elastic member such as rubber, is installed
in the ventilation hole 70b. The ventilation tube 97 has a
male thread which can be screwed with the female thread of
the ventilation hole 70b on the outer circumferential face
of the connection portion 98 located at the end portion
thereof and is connected to the ventilation hole 70b by
screwing the connection portion 98 into the ventilation
hole 70b.
Fig. 10 is an enlarged sectional view for showing a
connection portion 98. As shown in Fig. 10, a recessed
groove portion 98a, which is a groove extending
continuously to the circumferential direction, is formed on

the inner circumferential face of the connection portion 98
of the ventilation tube 98. Further, a circular-plate
shaped filter 99 is fitted and installed into the recessed
groove portion 98a.
It is noted that in place of forming the recessed
groove portion 98a on the inner circumferential face, a
ventilation tube 97 may be composed so as to undergo a
partial elastic deformation from the inner circumference to
press-fit a filter 99, by which the filter 99 is caught
diametrically by an elastic recovery force of the thus
elastically deformed ventilation tube 97 and fixed to the
ventilation tube 97.
Fig. 11 is a plan view of the filter 99, and Fig. 12
is a sectional view taken along S5 to S5 in Fig. 11. As
shown in these drawings, the filter 99 is composed of a
screen portion 99a for preventing the passage of dust or
the like and a ring portion 99b for enclosing the screen
portion 99a. The ring portion 99b is made with a material
higher in rigidity than the ventilation tube 97 such as
steel and able to increase a diametrical rigidity of the
filter 99.
Further, the ventilation tube 97 is formed by
extending to the wheel 201 from a portion connected with
the ventilation hole 70b and thereafter bending downward at
90 degrees. Thereby, it is possible to prevent water or the

like from entering into the brake main body 70 through the
ventilation tube 97 from outside.
As described above, the unit brake 100 of Embodiment
2 is additionally provided with a ventilation hole 70b
communicatively connecting the inside of the brake main
body 70 with the outside thereof in which a female thread
is made on the inner circumferential face, a ventilation
tube 97 formed by a tubular elastic member and having at
the end portion a connection portion 98 on which a male
thread screwed with the female thread of the ventilation
hole 70b is made, and a filter 99 fitted and installed into
the connection portion 98 and made with a material higher
in rigidity than the connection portion 98.
According to this constitution, since the connection
portion 98 is made with an elastic member, the filter 99
can be easily fitted into the inner circumferential face of
the connection portion 98 and fixed. Thereby, making
unnecessary is a special member for attaching the filter 99.
Further, if the connection portion 98 is formed to be
greater in outer diameter than the ventilation hole 70b, it
is possible to deform the connection portion 98 elastically
so as to reduce the diameter when the connection portion 98
is screwed into the ventilation hole 70b. In this instance,
the filter 99 is retained in a state that it is caught
diametrically by the connection portion 98 receiving a

force from the ventilation hole 70b in a direction in which
the diameter is reduced, thus making it possible to further
strengthen the connection with the connection portion 98.
An explanation has been so far made about embodiments
of the present invention. However, the present invention
shall not be limited to the above embodiments and may be
carried out by various modifications within the scope of
the claims.
Further, it is possible to carry out an invention of
the following brake cylinder device as a brake cylinder
device of a different perspective of the present invention.
The brake cylinder device of a different perspective
of the present invention relates to a brake cylinder device
which is provided with a normal brake having a first piston
in which a first pressure chamber and a first spring act so
as to oppose each other, with a rod projecting, wherein
pressure fluid is supplied to the first pressure chamber,
thereby the first piston is moved in the braking direction
against an urging force of the first spring and a spring
brake having a second piston installed so as to move in a
direction axially of the rod in which a second pressure
chamber and a second spring act so as to oppose each other,
with the rod penetrating through, wherein a state that
pressure fluid is supplied to the second pressure chamber
is shifted to a state that it is discharged, thereby the

second piston is moved in the braking direction by an
urging force of the second spring, or the brake cylinder
device which is capable of actuating both the normal brake
and the spring brake.
Then, the brake cylinder device of a different
perspective of the present invention has features in which
a covering formed so as to enclose and cover the end
portion arranged on the second spring with respect to the
second piston on the rod penetrating through the second
piston is installed on the side opposing the second spring
of the second piston, and the covering is disposed in such
a manner as to penetrate through the end. portion on the .
side at which the second spring is installed on the
cylinder main body including the normal brake and the
spring brake and project outside the cylinder main body .
It is noted that the brake cylinder device of a
different perspective of the invention can be carried out,
for example, as the brake cylinder device 1 of the present
embodiment. In other words, it can be carried out as a
brake cylinder device having the normal brake 11, the
spring brake 12, the cylinder main body 13, the covering 31
and others in the brake cylinder device 1. In this instance,
in a state given in Fig. 1 that the spring brake 12 is not
in operation, the second piston 27 is urged in the anti-
braking direction by the action of the second pressure

chamber 25 (and the third pressure chamber 28). Therefore,
an extent at which the covering 31 is projected outside the
cylinder main body 13 is a projection quantity X1 indicated
by the double-end arrow in the drawing. On the other hand,
in a state given in Fig. 3 that the spring brake 12 is in
operation, the second piston 27 is urged in the braking
direction by the action of the second spring 26. Therefore,
an extent at which the covering 31 is projected outside the
cylinder main body 13 is a projection quantity X2 indicated
by the double-end arrow in the drawing, which is smaller
than the projection quantity X1 when the spring brake 12 is
not in operation (specifically, established is a
relationship of X2 < X1). Consequently, according to the
present invention, it is possible to easily recognize
visually an operation state of the spring brake 12 from
outside the cylinder main body 13 only by confirming an
extent of the covering 31 projected from the projection
cylinder main body 13. It is noted that in order to more
easily recognize visually an extent of the covering 31
projected from the cylinder main body 13, for example, the
covering 31 may be painted in a color apparently
distinguishable from the color painted on the cylinder main
body 13 or a fluorescent paint may be used only at the
covering 31.

Claims
1.
A brake cylinder device comprising:
a normal brake having a first piston, a rod projecting
from the first piston, a first pressure chamber and a first
spring, the first piston being subjected to the action of
the first pressure chamber and the first spring sandwiching
the first piston therebetween, thereby moving the first
piston in a braking direction against an urging force of
the first spring when a supply of pressure fluid to the
first pressure chamber is started, a braking force being
generated with the movement of the first piston in the
braking direction;
a spring brake having a second piston installed so as to
move in an axial direction of the rod and penetrated by the
rod, a second pressure chamber and a second spring, the
second piston being subjected to the action of the second
pressure chamber and the second spring sandwiching the
second piston therebetween, threby moving the second piston
in the braking direction against an urging force of the
second spring when a supply of pressure fluid to the second
pressure chamber is stopped and a discharge of pressure
fluid from the second pressure chamber is started; and
a third pressure chamber arranged ,separated from the
second pressure chamber, on the opposite side of the

second spring relative to the second piston, the second
piston being subjected to the action of the third pressure
chamber, threby moving the second piston in an anti-
braking direction, that is a direction reverse to the
braking direction, against an urging force of the second
spring when pressure fluid supplied to the first pressure
chamber is supplied to the third pressure chamber.
2.
The brake cylinder device as set forth in claim 1,
wherein the second pressure chamber is arranged along the
circumferential direction on the outer circumference of the
second piston and the third pressure chamber is arranged
along the circumferential direction on the inner
circumference of the second piston.
3.
The brake cylinder device as set forth in claim 2,
wherein the second piston is provided with a cylindrical
wall disposed along the circumferential direction of the
second piston and projected in the braking direction to be
formed into a cylindrical shape, thereby sectioning the
second pressure chamber and the third pressure chamber, and
the cylindrical wall is slidingly in contact with an inner
cylindrical portion formed in a tubular shape along the

circumferential direction of the second piston inside a
cylinder main body including the normal brake and the
spring brake.
4.
The brake cylinder device as set forth in any one of
claim 1 to claim 3, wherein a covering is formed on the
same side as the second spring relative to the second
piston to enclose an end of the rod penetrating through the
second piston, the end being arranged on the same side as
the second spring relative to the second piston.
5.
The brake cylinder device as set forth in any one of
claim 1 through claim 3 which is provided with a
communication path for connecting communicatively the first
pressure chamber with the third pressure chamber, wherein
pressure fluid supplied to the first pressure chamber is
supplied to the third pressure chamber through the
communication path.
6.
The brake cylinder device as set forth in claim 5 which
is additionally provided with a clutch mechanism in which a
supply of pressure fluid to the second pressure chamber is

stopped and a discharge of pressure fluid from the second
pressure chamber is started, thereby giving a connection
state for connecting the rod with the second piston when
the second piston starts to move with respect to the rod by
an urging force of the second spring, and giving a non-
connection state for releasing the connection of the rod
with the second piston in a state that pressure fluid is
supplied to the second pressure chamber,
wherein the communication path is formed at the clutch
mechanism which is in the non-connection state.
7.
A unit brake by which a brake shoe is brought into
contact with the wheel of a vehicle to brake the rotation
of the wheel,
the unit brake comprising a brake cylinder device
described in any one of claim 1 to claim 3 arranged in
such a manner that the braking direction is parallel with
the shaft direction of the wheel;
an adjustor installed so as to advance and retract
freely in a direction perpendicular to the braking
direction inside a brake main body and having a supporting
shaft extended perpendicularly in the advancing and
retracting direction and the braking direction;
a roller installed on the supporting shaft so as to

rotate freely;
a push rod installed on the adjustor in which the brake
shoe is connected to the end portion extended from the
brake main body in the advancing direction of the
adjustor; and
a wedge firmly fixed to the rod,
wherein the wedge has an inclined acting surface that is
inclined in the braking direction and capable of urging the
roller in the advancing direction when the wedge is moved
in the braking direction.
8.
The unit brake as set forth in claim 7, which is
additionally provided with a spherical bearing for
providing support so that the push rod can swing with
respect to the adjustor.

It provides a brake device avoiding a simultaneous operation of a normal and spring brake with a simple mechanism
eliminated a double check valve.