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
2000-02-02
2001-02-27
Olszewski, Robert 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
C187S250000, C187S254000, C187S256000, C187S404000
Reexamination Certificate
active
06193018
ABSTRACT:
TECHNICAL FIELD
The present invention relates to elevator systems and, more particularly, to an elevator guide system requiring less installation and operation space than conventional elevator systems by utilizing combined function structures so that an elevator counterweight houses a drive system.
BACKGROUND OF THE INVENTION
Known elevator systems typically confine all elevator components to the hoistway or the machine room. The hoistway is an elongated, vertical shaft having a rectangular base in which the elevator car translates. The hoistway houses, among other things, the car guide rails which are usually a pair of generally parallel rails, fixed to opposite walls near the center of each wall, and running the approximate length of the hoistway. A counterweight having a pair of guide rails is positioned adjacent to a third wall. The hoistway houses additional components including terminal landing switches, ropes and sheave arrangements, and buffers for the counterweight and the car.
It is essential that the elevator components are located and oriented with precision prior to and during operation. The interior walls of the hoistway must be properly dimensioned and aligned, and the physical interface between the hoistway walls and the elevator components must be capable of withstanding varying load during use. It is particularly essential that the guide rails on which the car rides are properly positioned and solidly maintained. For quality of ride and safety, the guide rails need to be precisely plumb, square and spaced to avoid car sway, vibration and knocking. Guide rails are typically steel, T-shaped sections in sixteen foot lengths. The position of guide rails within the hoistway affects the position of the hoisting machine, governor and overhead (machine room) equipment. The machine room is typically located directly above the hoistway. The machine room houses the hoist machine and governor, the car controller, a positioning device, a motor generator set, and a service disconnect switch.
Because the various components of the hoistway and machine room require precise positioning and they produce varying and substantial loads, it is costly and complicated to assemble a typical traction elevator system.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved elevator system that optimizes use of space by providing a multi-function component that functions as a counterweight and a support for the drive machine and system, so that the need for a machine room and other space-consuming components is eliminated. It is a further object to provide an improved elevator system that achieves optimum efficiency in construction and materials by various means including, for example, providing a counterweight apparatus that stores potential energy as an integral part of the lift arrangement and that reduces the required torque for movement of the elevator car.
The present invention achieves the aforementioned and other objects by utilizing a novel arrangement of a drive machine and components housed within and moveable with a counterweight. In one embodiment, a counterweight-drive assembly includes a motor and drive pulley sized to maintain a narrow profile and to be suspended and to move in coordination with an elevator car. The counterweight-drive assembly is connected to an elevator car by one or more suspension ropes or belts. A traction belt, preferably toothed, is adapted to engage the drive pulley and is fixed vertically in the hoistway to form the counterweight-drive assembly path. The traction belt need not necessarily be a toothed belt. A conventional rope or a flat rope or belt may be used. As used herein, the terms “flat belt” and “flat rope” mean a belt or rope having an aspect ratio of greater than one, where the aspect ratio is the ratio of the belt or rope width to the thickness. When torque is applied through the drive pulley, the counterweight-drive assembly is caused to move up or down the hoistway. Additional deflection rollers side the traction belt around the drive pulley to attain sufficient surface contact area and resultant traction. Because a flat belt is used, sufficient traction is achieved with a small diameter drive pulley, thus conserving space. The optional use of a flat, toothed belt enhances traction further.
In another embodiment of the present invention, a counterweight-drive assembly includes a modular motor arrangement of four drive motors mounted to a counterweight body. Each motor has a sheave that cooperates with one of two fixed ropes attached at a hoistway ceiling and tensioned at the other end by a spring or tensioning weight. The motors and sheaves are preferably positioned at the four corners of the counterweight body. The motors and sheaves are proportioned and arranged to minimize thickness of the assembly and, thus, spaced required for mounting and operation. The path of the ropes around the upper and lower sheaves provides 360 degree effective wrap around for high traction. The use of multiple drive sheaves enables a large collective traction area with small diameter sheaves and small motors, thereby conserving space. Another advantage of using multiple drive sheaves and corresponding motors is that, in the event of failure of one motor, the others can continue the operation of the elevator system provided that they are sufficiently powered.
By having suspension belts separate from a traction belt, each can be respectively optimized for its particular function without concern for other performance characteristics, For example, the suspension ropes can be optimized for tension failure since they are not required to provide a traction medium. Further, the traction rope can be optimized for traction with only limited concern for tension failure, as the maximum tension it is subjected to results from the mass difference between the car and the counterweight. Additionally, the use of traction belts enables a reduction in motor size where, for example, cylindrical motors can be implemented instead of flat motors.
REFERENCES:
patent: 1722125 (1929-07-01), Bernhard
patent: 5566785 (1996-10-01), Hakala
patent: 565516 A1 (1993-10-01), None
patent: 2134209 (1984-08-01), None
patent: 2162283 (1986-01-01), None
patent: 4-55278 (1992-02-01), None
Ericson Richard J.
Ferrary Jean Marc
Rebillard Pascal
Schroder-Brumloop Helmut
Servia Armando
Olszewski Robert P.
Otis Elevator Company
Tran Thuy V.
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