Elevator – industrial lift truck – or stationary lift for vehicle – Having specific load support drive-means or its control – Includes linking support cable in drive-means
Reexamination Certificate
2001-11-28
2003-07-29
Ellis, Christopher P. (Department: 3652)
Elevator, industrial lift truck, or stationary lift for vehicle
Having specific load support drive-means or its control
Includes linking support cable in drive-means
C187S254000, C187S266000
Reexamination Certificate
active
06598707
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an elevator having no machine room disposed above an elevator shaft and, more specifically to an improved elevator capable of reducing the vertical height of a top space of the elevator shaft and of stably suspending an elevator cage.
2. Description of Related Art
Various elevators having no machine room disposed above an elevator shaft have been developed and proposed for the efficient utilization of space in buildings and for observing regulations regarding a right to sunshine.
FIGS. 6 and 7
show an elevator
1
previously proposed by the applicant of the present patent application in JP-A 157762/1999. This elevator
1
was developed to reduce the height of the top space of the elevator shaft and to reduce the horizontal cross section of the elevator shaft.
In this elevator
1
, a pair of connecting beams
6
is horizontally extending between the upper ends of a pair of cage guide rails
3
for guiding the vertical movement of an elevator cage
2
and the upper ends of a pair of counterweight guide rails
5
for guiding a vertical movement of a counterweight
4
respectively. A drive unit
9
is mounted on a support beam
8
that extends horizontally between the upper ends of a pair of counterweight guide rails
5
, in the vicinity of the inner side surface
7
a
of an elevator shaft
7
.
A pair of drive shafts
11
R and
11
L projects from a hoist
10
included in the drive unit
9
. A pair of traction sheaves
12
R and
12
L are mounted on the pair of drive shafts
11
R and
11
L, respectively. A pair of hoist cables
13
R and
13
L are wound around the pair of traction sheaves
12
R and
12
L, respectively.
One ends of the pair of hoist cables
13
R and
13
L are hitched directly to the elevator cage
2
by means of hitching devices
14
, and the other ends are hitched directly to the counterweight
4
by means of hitching devices
15
.
Referring to
FIG. 7
which shows a top plan view of the elevator
1
, the traction sheaves
12
R and
12
L are disposed in a space between the right inner side surface
7
R of the elevator shaft
7
and the right vertical outer side wall
2
R of the elevator cage
2
, and a space between the left inner side surface
7
L of the elevator shaft
7
and the left vertical outer side wall
2
L of the elevator cage
2
, respectively.
Therefore, the traction sheaves
12
R and
12
L do not interfere with the elevator cage
2
when the elevator cage
2
exists at the top portion of the elevator shaft
7
. Consequently, the vertical height of the top space and the horizontal cross section of the elevator shaft
7
can be reduced.
However, in this elevator
1
, the elevator cage
2
and the counterweight
4
are suspended by the pair of hoist cables
13
R and
13
L extending in so-called one-to-one roping arrangement, which is hitched directly to the elevator cage
2
and the counterweight
4
respectively.
Therefore, the hoist
10
must be capable of exerting a large torque and hence the hoist
10
has a comparatively big diameter.
Also the drive unit
9
including the hoist
10
mounted on the support beam
8
has a comparatively big diameter, there is still some room for reducing the vertical height of the top space of the elevator shaft
7
.
Further, the one end of the hoist cables
13
R and
13
L are secured to the elevator cage on the side of the counterweight
4
with respect to the center of gravity G of the elevator cage
2
, as shown in FIG.
6
.
Thus, there is still some room for improving the method of suspending the cage
2
for more stable suspension.
Since the traction pulleys
12
R and
12
L are on the outer side of the vertical side walls
2
R and
2
L of the cage
2
, respectively, as shown in
FIG. 7
, an extension shaft
17
needs to be connected to the drive shaft
11
R by a coupling
16
when the cage
2
has a big width, which increases the number of parts of the elevator.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to solve those problems in the prior art and to provide an elevator capable of further reducing the vertical height of a top space of an elevator shaft, of further stably suspending a cage, and comprising a reduced number of component parts.
According to a first aspect of the present invention, an elevator includes: a cage capable of vertically moving along cage guide rails in an elevator shaft, and provided on lower surface of its floor with cage-side sheaves; a counterweight capable of vertically moving along counterweight guide rails in the elevator shaft and provided with counterweight-side sheaves; two hoist cables extended in two-to-one roping arrangement around the cage-side sheaves and the counterweight-side sheaves such that one end part of each hoist cable suspends the cage and the other end part of the same suspends the counterweight; and a driving unit including traction sheaves around which the two hoist cables are wound, respectively, and held on upper ends of the counterweight guide rails.
The traction sheaves of the driving unit are disposed in a space between a side surface of the elevator shaft, facing the counterweight and a vertical side surface of the cage facing the same side surface of the elevator shaft when the cage is located at its uppermost position in the elevator shaft.
Since the cage and the counterweight are suspended by the hoist cables extended in two-to-one roping arrangement in the elevator in the first aspect of the present invention, the output torque of the driving unit, as compared with that of a driving unit for an equivalent elevator in which a cage and a counterweight are suspended in one-to-one roping arrangement, may be low and hence the driving unit may be of small dimensions.
Thus, the driving unit can be supported on the upper ends of the counterweight guide rails so that the traction sheaves are in the space between the side surface facing the counterweight of the elevator shaft and the vertical side wall facing the same side surface of the elevator shaft of the cage when the cage of the elevator is located at its uppermost position.
Since the driving unit and the cage do not lie on top of each other, the height of the top space of the elevator shaft may be small.
Since the driving unit and the cage do not lie on top of each other, the height of the top space of the elevator shaft may be small. Since the hoist cables are extended around the cage-side sheaves and the counterweight-side sheaves in two-to-one roping arrangement to suspend the cage and the counterweight, the driving unit can be disposed at a level below that of the ceiling of the cage as located at its uppermost position, so that height of the top space of the elevator shaft may be small.
When the hoist cables are thus extended around the sheaves in two-to-one roping arrangement, the respective moving speeds of the cage and the counterweight are half the winding speed of the traction sheaves; that is, the ratio of the winding speed to the moving speed of the cage and the counterweight is 2 to 1.
In the elevator according to the present invention, the four cage-side sheaves may be disposed respectively at four positions on the lower surface of the floor of the cage, arranged symmetrically with respect to a vertical line passing the center of gravity of the cage, and the two hoist cables wound respectively around the two traction sheaves may be wound around the two cage-side sheaves and around the other two cage-side sheaves, respectively, in two-to-one roping arrangement to support the cage.
In the elevator according to the present invention, the four cage-side sheaves may be disposed respectively at four positions on the lower portion of the cage, arranged symmetrically with respect to a center of gravity of the cage, and the two hoist cables wound respectively around the two traction sheaves may be wound around the two cage-side sheaves and around the other two cage-side sheaves, respectively, in two-to-one roping arrangement to support the cage. Thus, the gravity force and the lift
Miyakoshi Kazuaki
Nakagaki Shigeo
Shimane Kazuo
Tateyama Masaru
Ellis Christopher P.
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Kabushiki Kaisha Toshiba
Tran Thuy V.
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