ELEVATOR
FIELD OF THE INVENTION
The present invention relates to an elevator in which
a part of the rail is shared between the car and the
counterweight and which is suitable for reducing the number
of components, and which also contributes to reducing an
occupied space.
BACKGROUND OF THE INVENTION
Elevators have a car suspended by rope, and the car
moves vertically when the rope is wound by a hoist. In
general, connection of the car and the counterweight with
the rope reduces a capacity (energy consumption) and
external dimensions of the hoist, the counterweight
weighing as much as the value obtained by summing up the
own weight of the elevator car and half a maximum
passenger/freight load. The shaft of the elevator is
provided with four guide rails, one pair of the rails
guiding the vertical travel of the car and the other pair
guiding the vertical travel of the counterweight. The
rails of each pair are provided on the left and right sides
of the shaft.
The elevator car and the counterweight pass each
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other nearly in the middle of the shaft in the vertical
direction and do not pass each other at other positions.
Accordingly, JP7-010438 and JP2003-312960, for example,
disclose configurations in which the occupied volume of a
part of the shaft is reduced by shifting the counterweight
toward the car-travel side at a region where the
counterweight does not pass the car. In these
configurations, a curved rail for the counterweight or
mechanism that moves ropes to a hoist and/or to the
counterweight is provided.
A configuration in JP7-010438 includes a directacting
type of drive mechanism in a machine room, wherein a
deflector pulley is moved to a drive sheave to avoid
interference of ropes to the car. A configuration in
JP2003-312960 includes a direct-acting type of drive
mechanism for moving the counterweight horizontally on both
upper and lower sections of the counterweight frame. In
other embodiments, curved guide rails for movable sections
and guide devices are added aside from normal guide rails
and guide devices to ensure horizontal movement of the
counterweight at a predetermined position, making the
supply of electric power unnecessary.
The elevator's configuration described in JP7-010438
requires a large-sized drive device since the deflector
pulley around which the rope is wound needs to be driven
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horizontally. A machine beam for installing a hoist and a
vibration-isolating support beam for the machine beam are
also installed in the machine room. The machine room
therefore needs further enlargement to store the above
drive device including a section for receiving a reaction
force against a driving force as well as to avoid
interference of a non-moving portion to each rope. In
addition, an achievable dimensional-reduction zone of the
shaft is limited to an upper half of the shaft that enables
easy avoidance of interference between the car and the rope.
The configuration of the elevator described in
JP2003-312960 leads to enlargement of the drive device
because a mechanism for horizontally moving the entire
counterweight, except for the counterweight frame, is
mounted on the counterweight itself. Furthermore, in the
configurations of the above-mentioned other embodiments
including the added guide rails for movable sections and
guide devices, the number of components increases since
these elements are doubly included in these existing
devices. The zone of the shaft which can be reduced in
dimensions is not limited to the upper half of the shaft,
and a reduced space of the shaft is estimated as low as
approximately half the thickness of the counterweight
because the rope is allowed to pass over the rear surface
of the car when the car is present at the upper part of
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the shaft (this state is equivalent to a state in which the
counterweight is present at the lower part of the shaft).
The above two conventional techniques both aim mainly
at reducing the volume of the shaft, and nothing is
disclosed in the above two documents about a method of
reducing the number of components by dimensionally reducing
the rail for the counterweight.
Accordingly, to reduce both upper-half and lower-half
spaces occupied by the shaft and to dimensionally reduce
the counterweight rail, it has been necessary to solve new
problems such as how to avoid the interference between the
rope and the car particularly when the car is present at
the upper part of the shaft and how to reroute the
counterweight onto an evacuation rail. In addition, to
return the counterweight to the car rail after the car has
passed the counterweight at the center of the shaft in the
vertical direction, it is necessary to avoid the
interference between the rope and the car in the upper half
of the shaft and then, in the lower half of the shaft,
reroute the rope to an overlapping section on an orthogonal
projection of the car. To achieve this, it is further
necessary to secure an appropriate clearance from the car
at least temporarily by providing an idler pulley or the
like at the central part in the shaft instead of rerouting
the rope directly over the counterweight from a deflector
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pulley.
If the idler pulley is provided, the idler pulley
might or might not come into contact with the rapidly
moving rope, leading to unstable behaviors of the idler
pulley and the rope, which causes difficulty of obtaining
high reliability of the elevator from a perspective of the
lives of the rope and the idler pulley.
SUMMARY OF THE INVENTION
The present invention has been made to solve the
foregoing problems. It is an object of the invention to
provide an elevator which can decrease the number of
components by allowing the counterweight to use a sharable
part of the rail with the car and reducing the rail for the
counterweight and can have high reliability with
comparative ease.
In order to achieve the above object, an elevator of
the present invention comprises a car ascending and
descending in a shaft; a counterweight ascending and
descending in the shaft; a rope for hanging the car and the
counterweight; a drive device for driving the car and the
counterweight; and a car rail for guiding the car, wherein
the car is configured to travel a distance twice as long as
the counterweight travels, and wherein the counterweight is
configured to travel along a portion of the car rail.
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An elevator of the present invention can decrease the
number of components by allowing the counterweight to use a
sharable part of the rail with the car and reducing the
rail for the counterweight and can have high reliability
with comparative ease.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic illustration of an entire
elevator according to an embodiment of the present
invention;
FIG. 2 is a schematic view of the elevator according
to the embodiment of the present invention;
FIG. 3 is a schematic diagram showing a state of the
elevator immediately after a car and a counterweight passed
each other in the embodiment of the present invention;
FIG. 4 is a schematic diagram illustrating how the
counterweight moves to an evacuation rail in the embodiment
of the present invention;
FIG. 5 is a sectional view showing a shape of a car
rail and a state of roller guides for the car in the
embodiment of the present invention;
FIG. 6 is a sectional view representing a
relationship between the car rail and roller guides for the
counterweight in the embodiment of the present invention;
FIG. 7 is an enlarged view of essential elements
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showing a configuration of the counterweight in the
embodiment of the present invention; and
FIG. 8 is an enlarged view of essential elements
showing a configuration of an end part of a rope close to a
building in the embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIGS. 1 and 2 which are schematic
views of an elevator, an embodiment of the present
invention will be described. FIG. 1 is a diagrammatic
illustration of an entire elevator according to the
embodiment of the present invention, and FIG. 2 is a
schematic view of the elevator according to the embodiment
of the present invention.
A car 3 of the elevator is connected to a
counterweight 4 with a rope 2. A hoist 1 is installed in a
machine room 5 on the top of a shaft. The hoist 1 includes
a sheave and a motor. The machine room 5 includes, in
addition to the host 1, a deflector pulley 11 to change a
position of the rope 2. A conventional shaft 13 generally
has a uniformly-rectangular cross section from a pit to the
top as shown with the broken lines in FIG. 1. Accordingly,
in the conventional arts, the machine room 5 has the same
cross section as the shaft and houses various devices of
the elevator so that the shaft occupies a smaller area in
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the building.
FIG. 1 shows a sectional side view of the elevator
under the conditions that the car 3 is positioned on the
lowermost floor and the counterweight 4 is positioned on
the uppermost floor. As shown in FIG. 1, the rope 2 is
disposed on the top of the car 3, one end 6a of the rope 2
being connected to a main body of the car 3. Usually, the
other end 6b of the rope 2 is connected to an upper end of
the counterweight 4. In the present embodiment, however, a
pulley 10 is disposed on the counterweight 4 and the rope
end 6b is fixed to the building.
FIG. 2 shows the layout of the above elements
schematically for a better understanding. As shown in FIG.
2, the car 3 is directly connected to and hung by the rope
2, whereas the counterweight 4 is hung by the rope 2 in a
2:1 roping scheme. A distance which the counterweight 4
travels, therefore, is half a distance which the car 3
travels. (Hereinafter, this scheme is referred to as
"counterweighting 2:1 scheme". If the car 3 and the
counterweight 4 are connected with the rope 2, this
connection is hereinafter referred to as "1:1 scheme".)
This makes the counterweight 4 move upward and downward
only in an upper region of the shaft. In this case, a
lower half of the shaft is not used as a travel space for
the counterweight 4 and is used only as a travel space for
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the car 3. In other words, a space 12 in FIG. 1 can be
eliminated. The configuration of the elevator of the
present embodiment has a disadvantage that the
counterweight 4 has a mass twice as large as in the 1:1
scheme. However, this increment of the mass can be
minimized if the car 3 is constructed of lighter members.
In the shaft, a car rail 9 extends in the vertical
direction to guide vertical movements of the car 3.
Although a similar extending rail usually exists for the
counterweight 4 as well, a rail for the counterweight 4 is
not needed in the present embodiment. That is to say, the
counterweight 4 travels along the car rail 9 in an upper
section of the shaft, and the counterweight 4 is rerouted
onto the evacuation rail 16 in a neighborhood of the region
where the counterweight 4 passes the car 3. The evacuation
rail 16 includes a curved rail 7 and a straight rail 8.
Rollers (20a and 20b in FIG. 4) that are provided at a
center of the width of a rear surface of the counterweight
4 move along the evacuation rail 16. In FIG. 1, the
positions of the car 3 and counterweight 4 immediately
before the car 3 ascends and passes the counterweight 4 are
shown with the broken lines. The counterweight 4 is
beginning rotating to move leftward in order to avoid
interference with the car 3.
The rope 2 attached to the car 3 and the pulley 10
10
mounted on the counterweight 4 are arranged at a
substantially central position in the horizontal depth
direction of the elevator. The car rail 9 is placed toward
the counterweight away from a central position of the car 3
in the horizontal depth direction of the car 3 to prevent
each rope 2 of the car and the counterweight from coming
into contact with each other even during the travel of the
counterweight 4 along the car rail 9.
When the counterweight 4 is present at the highest
reachable position, the counterweight pulley 10 and the
rope end 6b fixed to the building are rotated in the
clockwise direction and inclined in the plane of the page.
This inclination enables the travel of the counterweight 4
along the car rail 9 without changing a horizontal position
of the rope end 6b according to a particular position of
the counterweight 4 and without bringing the ropes 2 into
contact with each other in the shaft. In the
counterweighting 2:1 scheme, the car 3 and the
counterweight 4 pass each other at a position of
approximately 3/4 from the lower end of the shaft in the
vertical direction.
FIG. 3 is a schematic diagram of a state immediately
after the car 3 has started ascending from the state of FIG.
1, the counterweight 4 has descended, and the car 3 and
counterweight 4 have passed each other for a further
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detailed description of the present embodiment. The
counterweight 4 passed the curved rail 7 and present on the
straight rail 8. At this time, the rope connecting the
counterweight 4 and the rope end 6b is nearly parallel to a
vertical line, and the counterweight pulley 10 and the rope
end 6b are not inclined. Even if the car 3 moves from this
position to the uppermost floor, the counterweight 4 only
descends along the straight rail 8 and goes down to a
position (a level 18 in FIG. 1) of nearly half of the
height of the shaft.
The shaft wall 17 on the counterweight 4 side is
configured to protrude toward the inside of the shaft
together with a minimum necessary clearance secured to
prevent the rope 2 on the counterweight 4 side from
interfering with the shaft. This structure enables the
building volume to be effectively used for residential
and/or tenant purposes by extending a space of the adjacent
building. In the counterweighting 2:1 scheme, the
counterweight 4 moves vertically at half a vertical moving
speed of the car 3. Since the counterweight 4 moves more
slowly than the car 3, the counterweight 4 can move
smoothly from the car rail 9 to the evacuation rail 16.
With reference to FIG. 4, which is a side view of the
counterweight 4, how the counterweight 4 moves to the
evacuation rail in the embodiment of the present invention
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will be described below. FIG. 4 is a sectional side view
of the counterweight 4 immediately before the counterweight
4 is rerouted onto the curved rail 7. A cross section of
the car rail 9 and the structures of roller guides 19a, 19b,
19c, and 19d will be shown in FIG. 6 described later.
Rollers 20a and 20b are mounted at the center of the rear
surface of the counterweight 4. When the counterweight 4
moves downward and the rollers 20a and 20b come into
contact with the curved rail 7, the counterweight 4 is
diverted from the car rail 9 and starts moving in a
rightward direction in FIG. 4. The roller guides 19a to
19d on the counterweight 4 are completely out of contact
with the rail 9 while the counterweight 4 is supported by
the rollers 20a and 20b. Once the counterweight 4 goes
further down and the lower left roller 19c transfers to a
roller support rail 29, the roller 20b moves away from the
curved rail 7 and the counterweight 4 continues to descend
with retaining the posture upright, supported by the roller
20a and the roller guide 19c.
One curved rail 7 is disposed at a center of the
width direction of the counterweight 4. A pair of the
roller support rails 29 is provided at positions
corresponding to the positions of the roller guides for the
counterweight 4, one on the left side and the other on the
right side.
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In FIG. 4, the counterweight 4 is guided along the
curved rail 7 by the rollers 20a, 20b, and 19a-19d of
contact type. Instead of the rollers, a magnetically
levitated guide of non-contact type can be used, allowing
smoother rerouting of the counterweight 4 and preventing
the rollers' wear and abrasion.
With reference to FIGS. 5 and 6, further detailed
structure of the car rail and roller guides in the present
embodiment will be described. FIG. 5 is a sectional view
of the car rail 9 and roller guides 21a, 21b, and 21c for
the car as viewed from above. The car rail 9 has a Ushaped
cross-section and has bending parts so that the
flange edges (both ends) of the U-shaped cross-section
slightly spread outward. The roller guides 21a and 21b for
the car which guide the car in the front - back direction
are respectively in contact with the inner side surfaces
30a and 30b of the U-shaped car rail 9 and pressed against
the inner side surfaces 30a and 30b by springs or the like,
which is not shown in FIG. 5. The roller guide 21c for the
car, which is perpendicular to the roller guides 21a and
21b, guides the car in the lateral direction and is in
contact with the inner side surface 30c of the U-shaped car
rail 9. As shown in FIG. 5, none of the roller guides 21a,
21b, and 21c for the car is in contact with the surface 31a
or 31b of the spread part at the end of the U-shaped car
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rail 9.
FIG. 6 is a top view showing the way the roller
guides 19a and 19b on the counterweight 4 transfer to the
curved rail 7. The roller guides 19a and 19b are placed
obliquely to the horizontal axis in FIG. 6, and the two
rollers (there are actually a total of eight rollers
because pairs of these particular rollers exist on upper,
lower, left, and right sides.) guide the movements of the
counterweight 4 in the horizontal and vertical directions
in FIG. 6. Although not shown in FIG. 6, the left side end
of the U-shaped car rail 9 does not have a bending part at
a region where the counterweight 4 reaches the curved rail
7. In other words, the U-shaped car rail 9 does not have
the surface 31a shown in FIG. 5. This means that when the
counterweight 4 is ready to move to the left, there are no
obstructions to hinder the movements of the counterweight 4
along with the roller guide 19b.
With reference to FIG. 7, a mechanism of the
counterweight pulley 10 in the present embodiment will be
described below, which avoids interference between the
ropes 2 and car 3. The counterweight pulley 10 is placed
above the counterweight 4. A bracket 23 axially supporting
the pulley 10 is rotatable about a supporting point 22 with
respect to the counterweight 4. FIG. 8 shows a mechanism
enabling the rope ends to be inclined. The ropes 2 are
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wound around wedges (not shown in FIG. 8) inside sockets 24
and connected to rods 32. The rods 32 are connected to a
lever 33 via springs 25. The lever 33 is rotatable about a
supporting point 27 with respect to a base 28. The entire
support part for the rope can be inclined since the lever
33 and the building are fixed via springs 26. The inclined
pulley portion in FIG. 7 and the inclined rope end portions
in FIG. 8 can be inclined to make the distance between the
counterweight and the rope ends shortest. The positions of
elements such as the curved rail 7 are decided to avoid
interference between the ropes 2 and the car 3 at all times.
As described above, the car rail 9 in the elevator of
the present embodiment is disposed slightly toward the
counterweight 4 away from a central position of the crosssectional
surface of the car 3 to avoid interference
between the ropes on the car side and the ropes on the
counterweight side so that the counterweight rail is
dimensionally reduced and the counterweight 4 travels along
the car rail 9.
In addition, when the car 3 is present in the upper
position of the shaft, the length of the ropes 2 on the
counterweight side is minimized by limiting the moving zone
of the counterweight 4 to the upper half of the shaft. In
order to achieve this, in the present embodiment, a movable
pulley is provided only for the counterweight 4, thus
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halving the travel distance of the counterweight 4 compared
to that of the car 2. This creates a secondary effect that
the vibration associated with the rerouting of the
counterweight 4 onto the evacuation rail can also be
reduced since the counterweight 4 travels at half a speed
compared to the equivalent of the travel distance of the
car 2.
In this configuration, the interference between the
rope 2 and the car 3 may only be considered for the upper
half of the shaft, and this interference can be avoided
with a simple mechanism that can change an angle between
the rope end and the counterweight pulley. The place where
the car 2 passes the counterweight 4 is a position lying in
the range of approximately 3/4 of the shaft height from the
lower end of the shaft. The counterweight 4 leaves the car
rail 9 around that position and then moves to the
counterweight evacuation rail.
According to the present embodiment, since the shaft
is reduced in the cross-sectional area except for a
vicinity of a vertical center region of the shaft, the
volume of the entire shaft can be reduced for more
effective use of the building volume. Additionally,
because the counterweight 4 travels along the car rail 9, a
counterweight rail should be installed for the length of
the evacuation rail as short as 1/4 or less of the overall
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height of the shaft, having no need for being installed for
the overall length of the height of the shaft. Thus the
time can be significantly shortened required for
fabrication, assembly, adjustment, and inspection for the
rail.
The present invention is not limited to the
configuration of the elements described in the above
embodiment. For example, although the roping of the 1:1
scheme is employed for the car 3 and the roping of the 2:1
scheme is employed for the counterweight 4 in the present
embodiment as a configuration in which the travel distance
of the car 3 is twice that of the counterweight 4, the
present invention is not limited to this configuration.
Roping of X:l scheme may be employed for the car 3 and
roping of 2X:1 scheme may be employed for the counterweight
4 in the present invention.
In such a case, a pulley around which the rope is
wound may be required to be installed above the
counterweight 4 in the shaft while the present embodiment
describes an example of providing the mechanism that
enables the rope end to be inclined. In this case, a shaft
pulley having the same structure as the inclining member
for the pulley provided on the counterweight 4 in FIG. 7
should be mounted on the shaft. That is to say, a bracket
should be provided for the shaft, which is configured to
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axially support the shaft pulley and rotates about a
supporting point in the shaft.
If the car 3 employs the roping of the 1:1 scheme and
the counterweight 4 employs the roping of the 2:1 scheme,
the present invention can be worked with simpler roping.
Moreover, the ropes can be shortened, the pulley on the
shaft is unnecessary, and the structure can be simplified.
The present invention is not limited to
configurations described in the above embodiment for the
shape of the car rail 9, relationships between the roller
guides 19a, 19b, 19c, 19d and roller guides 21a, 21b, 21c
for the car, the evacuation operation of the counterweight
4 onto the evacuation rail 16, and the mechanism enabling
the evacuation operation.
Furthermore, the present embodiment has described an
example in which the hoist 1 is employed as the drive
device for driving the car 3 and the counterweight 4.
However, the drive device in the present invention is not
limited to a hoist and can be a hydraulic drive apparatus
to work the present invention.
EXPLANATION OF REFERENCE CHARACTERS
1. Hoist
2. Rope
3. Car
19
4. Counterweight
6a. Car-side rope end
6b. The other rope end (Building-side rope end)
7. Curved rail
8. Straight rail
9. Car rail
10. Counterweight pulley
11. Deflector pulley
13. Conventional shaft
16. Evacuation rail
17. Shaft wall (Upper half of shaft)
18. Shaft (Bottom of protruding portion)
19a, 19b, 19c, 19d. Roller guides
20a, 20b. Rollers
21a-21c. Roller guides for the car
22. Supporting point
23. Bracket
24. Socket
25. Spring (for adjusting rope tension)
26. Spring
27. Supporting point
28. Base
29. Roller support rail
30a, 30b, 30c. Inner side surfaces of rail
31a, 31b. Inner side surfaces of rail (Protrusions)
32. Rod
33. Lever

WHAT IS CLAIMED IS:
1. An elevator comprising:
a car ascending and descending in a shaft;
a counterweight ascending and descending in the
shaft;
a rope for hanging the car and the counterweight;
a drive device for driving the car and the
counterweight; and
a car rail for guiding the car,
wherein the car is configured to travel a distance
twice as long as the counterweight travels, and
wherein the counterweight is configured to travel
along a portion of the car rail.
2. The elevator according to claim 1,
wherein the shaft has a central region in a vertical
direction of the shaft, the central region protruding in a
horizontal direction more than other region of the shaft.
3. The elevator according to claim 1,
wherein the counterweight includes a pulley around
which the rope is wound, and
wherein the pulley includes a rotational axis capable
of being inclined to a horizontal axis.
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4. The elevator according to claim 1, further
comprising:
a fixed part to which an end of the rope is fixed,
the fixed part capable of being inclined to a horizontal
axis.
5. The elevator according to claim 1,
wherein the car rail is placed toward the
counterweight away from a central position of the car in a
horizontal depth direction of the car.
6. The elevator according to claim 1, further
comprising:
a curved rail in a portion of the shaft,
wherein rollers placed on a rear surface of the
counterweight come into contact with the curved rail and
are guided along the curved rail above a region at which
the car and the counterweight pass each other in the shaft
so that the counterweight is diverted away from the car
rail.
7. The elevator according to claim 6,
wherein the curved rail has a U-shaped cross-section
and has bending parts so that both ends of the U-shaped
cross-section spread outward, and
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wherein a part of the curved rail has a bending part
so that only one end of the U-shaped cross-section spread
outward, the part being a place above the car where the
counterweight traveling along the car rail moves from the
car rail onto the curved rail.