DESCRIPTION
UNIT BRAKE
TECHNICAL FIELD
[0001]
The present invention relates to a unit brake which is used
for a railway vehicle or the like and brakes the rotation of
a wheel by pressing a brake shoe onto the wheel.
BACKGROUND ART
[0002]
A conventional unit brake for braking the rotation of a
wheel by pressing a brake shoe onto a wheel is described in
Patent Document 1.
This unit brake includes a main body having a supply opening
for supplying a pressure fluid, a pushing rod which protrudes
to the outside of the main body and is connected to a shoe at
the leading end, a supporting arm provided at the upper part
of the main body, and a hanger whose one end is pinned to the
supporting arm of the main body and the other end is supported
by the leading end of the pushing rod.
According to this arrangement, the load on the pushing rod
is reduced because the pushing rod is supported by the
supporting arm via the hanger.
[Patent Documents]

[0003]
[Patent Document 1] Japanese Unexamined Patent
Publication No. 59-192664
DISCLOSURE OF THE INVENTION
[Problem to be Solved by the Invention]
[0004]
The unit brake of Patent Document 1, however, is arranged
so that the supporting arm extends to reach above the pushing
rod and the shoe in order to prevent the hanger, the supporting
arm, and the shoe from interfering one another. Because of
this arrangement, an interference with bogie-related
components (such as components of the bogie and an air tube)
which are provided above the shoe is likely to occur.
In particular, in case where a used unit brake is replaced
with a new unit brake, it becomes necessary to replace the
existing bogie-related components with new ones if an
interference between the new unit brake and the existing
bogie-related components occurs.
[0005]
An object of the present invention in consideration of the
problem above is .to provide a unit brake which reduces the-load
on the pushing rod and restrains an interference with
bogie-related components or the like which are provided above
the unit brake.

[Means for Solving the Problem]
[0006]
A unit brake of the present invention has following
features to achieve the object above. In other words, the unit
brake of the present invention includes the following features
singly or in combination.
[0007]
The unit brake according to the first aspect of the present
invention for achieving the object above includes: a pushing
rod which is arranged to move in and out to and from a brake
main body; a shoe head which is rotatably connected to a leading
end portion of the pushing rod in an advancing direction and
to which a brake shoe which contacts a wheel to brake the
rotation of the wheel is attached; a link component which is
connected to the shoe head at a position above a junction between
the shoe head and the pushing rod to be rotatable about an axis
which is substantially in parallel to a rotation axis about
which the shoe head rotates with respect to the pushing rod;
and a supporting arm which is connected to the brake main body
at a position below the junction between the shoe head and the
pushing rod and is rotatable about an axis substantially in
parallel to a rotation axis about which the link component
rotates with respect to the pushing rod of the shoe head.
[0008]
This arrangement makes it possible to support the shoe head

by the supporting arm via the link component. The load on the
pushing rod is therefore reduced.
In addition to the above, since the supporting arm is
provided below the pushing rod and the link component is
provided between the supporting arm and the shoe head, the
supporting arm and the link component are less likely to
interfere with the bogie-related components or the like
provided above the shoe head.
[0009]
According to the second aspect of the present invention,
the unit brake further includes an extension portion which is
integrated with the pushing rod and is connected with the shoe
head at a position remote from the junction between the shoe
head and the pushing rod.
[0010]
This arrangement prevents the shoe head from tilting with
respect to the pushing rod.
[0011]
According to the third aspect of the present invention,
the unit brake is arranged so that the extension portion is
connected to the shoe head in such a way as to restrict, by
friction, tilting of the shoe head With respect to the pushing
rod.
[0012]
According to this arrangement, the shoe head is tilted with

respect to the pushing rod when a force larger than a
predetermined friction force restricting the tilting of the
shoe head is exerted to the shoe head. For this reason, even
if at the time of braking a gap is formed between the wheel
and the brake shoe because the angle of the braking surface
o"f-the brake shoe is improper, the angle of the shoe head is
properly adjusted as below. In other words, as the shoe head
is pushed toward the wheel by the pushing rod, a tilting force
larger than the predetermined friction force is exerted to the
shoe head, and hence the angle of the shoe head is automatically
adjusted in a suitable manner. This causes the wheel to further
closely contact the brake shoe at the time of braking.
[0013]
.According to the fourth aspect of the present invention,
the unit brake is arranged so that the supporting arm is provided
above the junction between the extension portion and the shoe
head.
[0014]
According to this arrangement, since the supporting arm
is not provided at a position below the shoe head, it is possible
to prevent the supporting arm from contacting components on
the ground side, when the vehicle runs.
[0015]
According to the fifth aspect of the present invention,
the unit brake includes: an adjuster which is provided to move

with the pushing rod inside the brake main body and has a
supporting shaft which is orthogonal to advancing and
withdrawing directions of the pushing rod; a roller rotatably
attached to the supporting shaft; and a wedge-shaped component
which is moved, by a driving mechanism provided inside the brake
main body, in a direction orthogonal to the advancing and
withdrawing directions of the pushing rod and to the supporting
shaft, wherein, the wedge-shaped component has a tilted surface
which is tilted with respect to the moving direction of the
wedge-shaped component and biases, when moving toward the
roller, the roller in the advancing direction of the pushing
rod.
[0016]
According to this arrangement, the mechanism for advancing
and withdrawing the pushing rod is downsized in the direction
orthogonal to the advancing and withdrawing directions of the
pushing rod and to the supporting shaft. "
[0017]
According to the sixth aspect of the present invention,
the unit brake is arranged so that the supporting shaft is
provided to vertically extend, and the supporting arm is
connected to the link component at a position above the lower
end of the supporting shaft.
[0018]
According to this arrangement, since the supporting arm

is not provided at a position lower than the lower end of the
supporting shaft, it is possible to prevent the supporting arm
from contacting components on the ground side, when the vehicle
runs.
[Effects of the Invention]
[0019]
The present invention makes it possible to reduce the load
on the pushing rod and restrains the interference of the
supporting arm and the link component with the bogie-related
components, because the shoe head is supported by the
supporting arm via the link component.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020]
Fig. 1 is a schematic partial cross section of a unit brake
according to First Embodiment of the present invention.
Fig. 2 is a schematic cross section of the unit brake 1
taken along the S1-S1 line of Fig. 1.
Fig. 3 is a schematic cross section of the unit brake 1
taken along the S2-S2 line in Fig. 1.
Fig. 4 is an enlarged view of the friction generating
mechanism of Fig. 3.
Fig. 5 is a schematic partial cross section of a unit brake
according to Second Embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION
[0021]
The following will describe an embodiment of the present
invention with reference to figures.
[0022]
(First Embodiment)
The present embodiment will describe, as an example, a unit
brake used for braking the rotation of a wheel of a railway
vehicle.
Hereinafter, a direction in parallel to the rotation axis
of the wheel will be denoted as "vehicle width direction", a
direction in parallel to the traveling direction of the vehicle
will be denoted as "vehicle front-back direction", and a
direction orthogonal to the vehicle width direction and the
vehicle front-back direction will be denoted as "vehicle
vertical direction".
[0023]
The unit brake 1 shown in Fig. 1 to Fig. 3 includes a
box-shaped brake main body 11 having a supply opening 11a
through which a pressure fluid is supplied and exhausted, a
pushing rod 12 which is arranged to be able to move in and out
to/from the brake main body 11, a shoe head 13 connected to
the leading end of the pushing rod 12, a link component 14
connected to the shoe head 13, and supporting arms 15 which
are provided to substantially horizontally protrude from the

front surface of the brake main body 11 and connected to the
link component 14.' At the front surface of the shoe head 13
is attached a brake shoe (not illustrated) which contacts the
tread of the wheel to brake the rotation of the wheel.
[0024]
.
The pushing rod 12 is moved by a later described mechanism
in the brake main body 11 in a direction toward the wheel (i.e.
the direction indicated by the arrow XI in Fig. 1) and in a
direction away from the wheel (i.e. the direction indicated
by the arrow X2 in Fig. 1)..
[0025]
The shoe head 13 includes a pair of side plates 31 which
are in parallel to each other with a predetermined interval
therebetween and an arc-shaped front plate portion 32 connected
to the front edges of the pair of side plates. The front plate
portion 32 is divided into an upper portion and a lower portion.
The leading end portion of the pushing rod 12 in its advancing
direction is disposed between the pair of side plates 31, and
a shoe head pin 91 extending in the vehicle width direction
penetrates the pair of side plates 31 and the leading end portion
of the pushing rod 12. With this arrangement, the shoe head
13 is connected to the pushing rod 12 to be rotatable about
the shoe head pin 91.
[0026]

The pushing rod 12 is provided with a downward-extending
extension plate 16 (extension portion) at the leading end
portion in the advancing direction. The extension plate 16
is integrated with the pushing rod 12. This plate 16 extending
downward forms an angle of about 90 degrees with the pushing
rod 12.
As the enlarged view in Fig. 4 shows, the lower end portion
of the extension plate 16 has surfaces 16a which are in parallel
to the advancing and withdrawing directions of the pushing rod
12. This lower end portion of the extension plate 16 is
disposed between the pair of side plates 31 of the shoe head
13. Furthermore, at the lower end portion of the extension
plate 16 is formed a long hole 16b which extends in the
substantially same direction as the rotation of the shoe head
13 (see Fig. 1) .
[0027]
Through the side plates 31 of the shoe head 13 sandwiching
the long hole 16b, concentric holes 31a are formed,
respectively. To these concentric holes,31a, a spring box 33
is inserted to be slidable in the axial directions. Inside
the spring box 33 is provided a coil spring 34. Into a center
hole 33a of the spring box 33 is inserted an attaching bolt
35 . By tightening a double nut '38, the spring box 33 is shortened
crosswise.
[0028]

Between the parallel surfaces 16a of the extension plate
16 and washers 37, friction plates 36 are interposed. To these
washers 37, a biasing force is exerted inward from the coil
springs 34. The friction plates 36 and the washers 37 are
supported by the attaching bolt 35 penetrating the long hole
16b. It is therefore possible to adjust the force with which
the friction plates 36 presses the extension plate 16, by
changing,the degree of tightening of the double nut 38.
[0029]
As shown in Fig. 3, the upper end portion of the link
component 14 is connected to the upper end portion of the shoe
head 13 to be rotatable about an axis in parallel to the shoe
head pin 91.
More specifically, the link component 14 has a pair of plate
members 14a which are provided to sandwich the shoe head 13
and vertically extend. The pair of plate members 14a have,
at the upper ends, axis components 14b which protrude in the
vehicle width direction. In the meanwhile, at the upper end
of the shoe head 13 is formed a through hole 13a penetrating
plate members 14a in the vehicle width direction. The pair
of plate members 14a are arranged so that the respective axis
components 1.4b are inserted into the through hole 13a of the
shoe head 13 from the respective sides. While the leading ends
of the axis components 14b are brought into contact each other,
the shaft of a connection bolt 94 is inserted into the through

holes 14c which are concentric with the shaft center of the
axis components 14b, and the axis components 14b are connected
to each other by being sandwiched by the head of the connection
bolt 94 and a nut 95 from the respective sides. As such, the
link component 14 is connected to the shoe head 13 to be
rotatable about the axis components 14b.
[0030]
As shown in Fig. 1 to Fig. 3, the brake main body 11 has,
in an integrated manner, a pair of supporting arms 15 which
protrude in the advancing direction of the pushing rod 12. The
pair of supporting arms 15 are provided on the respective sides
of the shoe head 13 in the width directions, at the lower end
portion of the brake main body 11. The pair of supporting arms
15 are connected via link pins 92 to the lower end portions
of the pair of plate members 14a of the link component 14 so
that the supporting arms 15 are rotatable. The link pins 92
are arranged to be in parallel to the shoe head pin 91.
The pair of supporting arms 15 are provided above the ends
of the attaching bolt 35 which is at the lower end portion of
the shoe head 13.
[0031]

The unit brake 1 includes, in the brake main body 11, a
piston 21 arranged to be movable in the vehicle width direction,
a spring 22 biasing the piston 21 toward the supply opening

11a, an adjuster 25 which is provided on the pushing rod 12
and has a pair of supporting shafts 24 vertically protruding
both upward and downward, first rollers 2 6 and second rollers
27 rotatably attached to the pair of supporting shafts 24, third
rollers 28 attached to the brake main body 11 behind the first
rollers 26 to oppose the first rollers 26, a pair of wedge-shaped
components 29 fixed to the piston 21, and a spring 30 biasing
the adjuster 25 in the withdrawing direction (indicated by the
arrow X2) of the pushing rod 12. The adjuster 25 is attached
to the pushing rod 12 in the brake main body 11 via a sleeve
23, and advances and withdraws with the pushing rod 12.
[0032]
Each of the wedge-shaped components 29 is fixed to the
piston 21 on the base end side and is arranged so that its tapered
leading end portion is inserted into the space between the first
roller 26 and the third roller 28. The wedge-shaped component
29 has a counteraction surface 29a substantially in parallel
to the vehicle width direction and an operating surface 29b
tilted with respect to the counteraction surface 29a. The
wedge-shaped components 29 are paired in the vehicle vertical
direction.
[0033] . '
The piston 21 moves in such a way as to insert the leading
end of the wedge-shaped component 2 9 into the space between
the first roller 26 and the third roller 28, as a pressure fluid

is supplied from the supply opening 11a to the pressure chamber
11b of the brake main body 11. In other words, the piston 21
moves in the direction indicated by the arrow Yl in Fig. 2
(hereinafter, this direction will be referred to as "braking
direction") . The spring 22 biases the piston 21 in the
direction opposite to the braking direction, (i.e. in the
direction indicated by the arrow Y2 in Fig. 2).
[0034]
The second roller 27 is provided at the end portion of the
supporting shaft 24 of the adjuster 25. The first roller 26
is provided to be closer to the sleeve 23 than the second roller
27. The third roller 28 is rotatably attached to the brake
main body 11 via a vertically extending roller pin 93.
The brake main body 11 is provided with a guide 11c. The
second roller 27 contacts the guide 11c and rotationally moves
thereon. The guide 11c is on the opposite side of the piston
21 from the second roller 27. It is noted that a surface of
the guide 11c contacting the second roller 27 is orthogonal
to the moving direction of the piston 21.
[0035]

Now, how the unit brake 1 operates will be described.
When braking, as a pressure fluid is supplied from the
supply opening 11a to the pressure chamber 11b, the piston 21
and the wedge-shaped components 29 move toward the adjuster

25 (i.e. move in the direction indicated by the arrow Y1).
At the same time, the first rollers 26 contacting the
operating surfaces 29b of the wedge-shaped components'29 are
pushed forward (i.e. in the direction indicated by the arrow
X1), with the result that the adjuster 25, the sleeve 23, and
the pushing rod 12 move forward. In so doing, the second
rollers 27 move forward while contacting the guide 11c and
rotating. As a result, the shoe head 13 at the front end of
the pushing rod 12 move toward the tread of the wheel.
At the same time, the shoe head 13 moving toward the tread
of the wheel is slightly moved in the vertical direction on
account of the rotation about the link pins 92 which are at
the lower end of the link component 14.
It is noted that, since the pushing rod 12 is connected
to the sleeve 23 via an unillustrated ball bearing, the leading
end of the pushing rod 12 is allowed to circularly move in the
vertical direction.
[0036]
In addition to the above, the rotation of the shoe head
13 about the shoe head pin 91 is restricted by the friction
force of the friction plate 36 which is provided between the
extension plate 16 extending from the pushing rod 12 and the
lower end portion of the shoe head 13. For this reason, the
tilting angle of the shoe head 13 with respect to the pushing
rod 12 is unchanged until the brake shoe contacts the wheel.

As the brake shoe of the shoe head 13 contacts the tread
of the wheel, the rotation of the wheel is braked.
[0037]
When the brake shoe and the wheel are not equidistant from
each other at the time of the contact of the brake shoe to the
tread of the wheel, one of the upper and lower edges of the
shoe head 13 is loaded. When the loaded force exceeds the
friction force between the extension plate 16 and the friction
plate 36, the shoe head 13 rotates about the shoe head pin 91
so that the tread of the wheel closely contacts the brake shoe.
The pushing rod 12 is pulled back when the brake is released.
However, the shoe head 13 is pulled back while keeping the
position after the rotation, on account of the friction force
of the friction plate 36.
[0038]
As described above, the unit brake 1 includes: the pushing
rod 12 arranged to be able to move in and out to/from brake
main body 11; the shoe head 13 which is rotatably connected
to the leading end portion of the pushing rod 12 in the advancing
direction and to which the brake shoe which contacts the wheel
to brake the rotation of the wheel is attached; the link
component 14 which is provided, at a position above the junction
between the shoe head 13 and the pushing rod 12, to be rotatable
about an axis substantially in parallel to the rotation axis
about which the shoe head 13 rotates with respect to the pushing

rod 12; and the supporting arms 15 which are provided, at
positions below the junction between the shoe head 13 and the
pushing rod 12 in the brake main body 11, to be rotatable about
an axis substantially in parallel to the rotation axis about
which the link component 14 rotates with respect to the pushing
rod 12 of the shoe head 13.
[0039]
According to this arrangement, the shoe head 13 is
supported by the supporting arms 15 via the link component 14.
That is to say, since a part of the vertical force exerted to
the shoe head 13 is transferred to the supporting arms 15 via
the link component 14, it is possible to reduce the vertical
force transferred from the shoe head 13 to the pushing rod 12.
As such, the load on the pushing rod 12 is reduced.
[0040]
In addition to the above, the supporting arms 15 are
provided below the pushing rod 12,- the link component 14 is
provided between the supporting arms 15 and the shoe head 13,
and the link component 14 does not' protrude above the upper
end of the shoe head 13. Because of this arrangement, the
supporting arms 15 and the link component 14 are less likely
to interfere with the bogie-related components or the like,
which are provided above the shoe head 13.
[0041]
In addition to the above, the extension plate 16 is

integrated with the pushing rod 12 and connected to the shoe
head 13 at a position distant from the junction between the
shoe head 13 and the pushing rod 12. This prevents the shoe
head 13 from tilting with respect to the pushing rod 12.
It is noted that the effect above is achieved not only when
the connection between the extension plate 16 and the shoe head
13 is made via the friction plate 36 but also when the connection
is achieved by using a pin or the like.
[0042]
The extension plate 16 is connected to the shoe head 13
to restrict, by a friction force, the tilting of the shoe head
13 with respect to the pushing rod 12.
[0043]
According the this arrangement, the shoe head 13 rotates
about the shoe head pin 91 with respect to the pushing rod 12,
when a force larger than a predetermined friction force exerted
from the extension plate 16 and by which the tilting of the
shoe head 13 is restricted is exerted to the shoe head 13. For
this reason, even if at the time of braking a gap is formed
between the wheel and the brake shoe because the angle of the
braking surface of the brake shoe is improper, the angle of
the shoe head 13 is properly adjusted as below.
That is to say, as the shoe head 13 is pushed toward the
wheel and only the upper or lower side of the brake shoe contacts
the tread of the wheel, the shoe head 13 receives a rotational

force about the shoe head pin 91. This rotational force
automatically adjusts the angle of the shoe head 13 so that
the bra-ke shoe evenly contacts the tread of the wheel with a
suitable angle, against the predetermined friction force
generated between the friction plate 36 and the extension plate
16. This causes the wheel to further closely contact the brake
shoe at the time of braking.
[0044]
In addition to the above, since the supporting arms 15 are
provided above the junction between the extension plate 16 and
the shoe head 13, it is possible to prevent the supporting arms
15 from contacting components provided on the ground side, when
the vehicle runs.
[0045]
In addition to the above, even if the connecting members
(attaching bolt 35 or the like) by which the extension plate
16 is connected to the shoe head 13 protrude from the profile
of the shoe head 13 toward the outside in the vehicle width
direction, it is possible to reduce the distance between the
two supporting arms 15 in the vehicle width direction because
the supporting arms 15 are provided at the upper part to avoid
the positions of the connecting members.
This makes it possible to prevent the mechanism for
supporting the shoe head 13 from being excessively large in
the vehicle width direction.

[0046]
In addition to the above, the unit brake 1 includes, in
the brake main body 11, the adjuster 25 which advances and
withdraws with the pushing rod 12 and has the supporting shafts
24 extending in the directions orthogonal to the advancing and
withdrawing directions of the pushing rod 12, the first rollers
26 rotatably attached to the supporting shafts 24, the piston
21 which is provided in the brake main body 11 and moves in
the direction orthogonal to the advancing and withdrawing
directions of the pushing rod 12 and to the supporting shaft
against the biasing force of the spring 22 when a pressure fluid
is supplied from the supply opening 11a to the pressure chamber
lib, and the wedge-shaped components 29 fixed to the piston
21. Each of the wedge-shaped components 29 has the operating
surface 2 9b tilted with respect to the moving direction of the
wedge-shaped components 29. When the wedge-shaped components
29 move toward the first rollers 26 with the piston 21, the
operating surfaces 29b bias the first rollers 26 in the
advancing direction of the pushing rod 12.
[0047]'
According to this arrangement, the mechanism for advancing
and withdrawing the pushing rod 12 is downsized in the direction
orthogonal to the advancing and withdrawing directions of the
pushing rod 12 and to the supporting shafts 24.
[0048]

In addition to the above, since the supporting shafts 24
are arranged to vertically extend, the mechanism for advancing
and withdrawing the pushing rod 12 is downsized in the vehicle
width direction.
[0049]
In addition to the above, since the supporting arms 15 are
connected to the link component 14 at positions above the lower
ends of the supporting shafts 24, it is possible to prevent
the supporting arms 15 from contacting components provided on
the ground side, when the vehicle runs.
[0050]
It is noted that the supporting shafts 24 are housed in
the brake main body 11 and move within a predetermined range
inside the brake main body 11. For this reason, a space in
front of the position where the supporting shafts 24 are closest
to the shoe head 13 (hereinafter, the most advanced position)
is likely to be a dead space.
In this regard, the supporting arms 15 connected to the
link component 14 at positions higher than the lower end of
the supporting shaft 24 are provided in front of the most
advanced position of the supporting shafts 24. In this way,
highly rigid supporting arms 15 are formed by effectively using
the dead space.
[0051]
In addition to the above, the present embodiment is

arranged so that the link component 14 is connected to the upper
end portion of the shoe head 13. This restrains the vertical
movement of the shoe head 13 which occurs in accordance with
the movement of the pushing rod 12.
[0052]
In addition to the above, the present embodiment is
arranged so that the extension plate 16 is connected to the
lower end portion of the shoe head 13. As such, because the
extension plate 16 is connected at the most distant part of
the shoe head 13 from the shoe head pin 91, the tilting of the
shoe head 13 is restricted by a relatively small force.
[0053]
(Second Embodiment)
The following will describe a unit brake 2 of Second
Embodiment with reference to Fig. 5. It is noted that the same
components as in First Embodiment are denoted by the same
reference numerals, respectively, and the description thereof
will be omitted.
In the unit brake 2, the directions of the brake main body
41 and the mechanism therein are different from those in First
Embodiment.
More specifically, the unit brake 2is arranged so that a
supply opening 11a is formed at the upper end portion of a brake
main body 41, and the piston 21 and the wedge-shaped component
29 move in the vehicle vertical direction.

The supporting shafts 24 of the adjuster 25 extend in the
vehicle width direction.
The supporting arm 45 is arranged to extend forward from
the corner between the front surface and lower end surface of
the brake main body 41, and its leading end is connected to
the lower end portion of the link component 14.
The shoe head 13 is positioned so that its upper end is
lower than the upper end of the brake main body 41.
[0054]
According to this arrangement, the space occupied by the
brake main body 41 is downsized in the vehicle width direction.
[0055]
While illustrative and presently preferred embodiments of
the present invention have been described in detail herein,
it is to be understood that the inventive concepts may be
otherwise variously embodied and employed within the scope of
claims.
REFERENCE NUMERALS
[0056]
1 and 2 UNIT BRAKE
11 BRAKE MAIN BODY.
12 PUSHING ROD
13 SHOE HEAD
14 LINK COMPONENT

15 SUPPORTING ARM
16 EXTENSION PLATE (EXTENSION PORTION)

24 SUPPORTING SHAFT
25 ADJUSTER
26 FIRST ROLLER
29 WEDGE-SHAPED COMPONENT

CLAIMS
1. A unit brake comprising:
a pushing rod which is arranged to move in and out to and
from a brake main body;
a shoe head which is rotatably connected to a leading end
portion of the pushing rod in an advancing direction and to
which a brake shoe which contacts a wheel to brake the rotation
of the wheel is attached;
a link component which is connected to the shoe head at
a position above a junction between the shoe head and the pushing
rod to be rotatable about an axis which is substantially in
parallel to a rotation axis about which the shoe head rotates
with respect to the pushing rod; and
a supporting arm which is connected to. the brake main body
at a position below the junction between the shoe head and the
pushing rod and is rotatable about an axis substantially in
parallel to a rotation axis about which the link component
rotates with respect to the pushing rod of the shoe head.
2. The unit brake according to claim 1, further
comprising:
an extension portion which is integrated with the pushing
rod and is connected with the shoe head at a position remote
from the junction between the shoe head and the pushing rod.

3. The unit brake according to claim 2, wherein,
the extension portion is connected to the shoe head in
such a way as to restrict, by friction, tilting of the shoe
head with respect to the pushing rod.
4. The unit brake according to claim 2 or 3, wherein,
the supporting arm is provided above the junction between
the extension portion and the shoe head.
5. The unit brake according to claim 1 or 2, further
comprising:
an adjuster which is provided to move with the pushing
rod inside the brake main body and has a supporting shaft which
is orthogonal to advancing and withdrawing directions of the
pushing rod;
a roller rotatably attached to the supporting shaft; and
a wedge-shaped component which is moved, by a driving
mechanism provided inside the brake main body, in a direction
orthogonal to the advancing and withdrawing directions of the
pushing rod and to the supporting shaft, wherein,
the wedge-shaped component has; a tilted surface which is
tilted with respect to the moving direction of the wedge-shaped
component and biases, when moving toward the roller, the roller
in the advancing direction of the pushing rod.

6. The unit brake according to claim 5, wherein,
the supporting shaft is provided to vertically extend,
and
the supporting arm is connected to the link component at
a position above the lower end of the supporting shaft.

The unit brake 1 includes a pushing rod 12 which is arranged
to move in and out to and from a brake main body 11, a shoe
head 13 which is rotatably connected to a leading end portion
of the pushing rod 12, a link component 14 which is connected
to the shoe head 13 at a position above a junction between the
shoe head 13 and the pushing rod 12 to be rotatable about an
axis which is substantially in parallel to a rotation axis about
which the shoe head 13 rotates with respect to the pushing rod
12, and a supporting arm 15 which is connected to the brake
main body 11 at a position below the junction between the shoe
head 13 and the pushing rod 12 and is rotatable about an axis
substantially in parallel to a rotation axis about which the
link component 14 rotates with respect to the pushing rod 12
of the shoe head.