Patent GB-190603732-A (GB)
Title: Improvements in Stopping Devices for Elevators or Lifts.
Filed: 1906-02-15
Granted: 1906-05-24
Abstract: 3732. Otis Elevator Co., [Otis Elavator Co.]. Feb. 15. Lifts; overwinding,preventing.-Relates to means for automatically and gradually stopping a lift cage at predetermined points in its travel by means of inclined ropes or the like engaged by pulleys carried on the cage ; means are also provided for controlling the cage if the automatic apparatus becomes deranged. In the arrangement shown in Fig. 1, the cage is supported on plunger 2 moving vertically in the hydraulic cylinder 3. The cage is stopped at the upper and lower limits of its travel by the motion of the lever 12, which operates a pilot valve 6 controlling the stop-motion valve 4. The lever 12 is connected to a rope 13, which passes, as shown, around guide-pulleys in the well and on the cage, and has its ends fixed to a weight 20. As the cage rises from the position shown in Fig. 1, the lever 12 is swung over and the stop valve 4 operated. Between the limits of its motion, the cage is controlled by a hand-lever in the cage operating the main valve 69, which, together with the automatic stop valve 4, is shown in Fig. 6, in which the stop valve has just operated to stop the cage at its lower limit, the hand-lever 32 being swung over to allow the cage to descend. The pilot valve 6 is in position to allow communication between the supply port and the lower end of the valve-chest 17, thereby raising the valve piston 30, and closing communication between the plunger cylinder 3 and the exhaust port 8. The stoppage of the car will be gradual, owing to the small size of the passages communicating with the pilot valve and the consequent slow.motion of the stop-valve pistons 29, 30. Upon the car starting upwardly again, the lever 12 moves the pilot valve 6 in the opposite direction, thus causing the valves 29, 30 to return to central position, and also, through the lever 12 turning about the connexion 18, returning the pilot valve, to central. position. The main valve 69 for controlling the motion of the cage between its upper and lower limits is operated through a pilot valve 70 and the throttle valve 68, the movement of which is effected by the hand-lever and rope 47, and the pivoted lever 66. The valves 70, 68 are of any suitable construction. The movement of the handlever 32 to the right operates the pilot valve 70, and allows pressure water to pass above the piston 53, thereby depressing the two valves 55, 56 and their balance pistons. Communication is thus opened from the main supply pipe 48 through the pipe 71 and the stop-valve chamber to the ram cylinder 3. At the same time, the exhaust 49 is shut off from the pipe 72, so that, when the stop valve 4 returns to its central position, no water can pass from the cylinder 3 to the main exhaust 49. In the event of the parting of the rope 13, the cage will always be automatically stopped either at the bottom or top of its travel, except in the case of both portions of the rope breaking when the cage, and consequently the stop valve, is in a central position. In a modified arrangement, shown in Fig. 7, the ends of the inclined rope 13 are passed over separate pulleys, and support separate counterweights, each adapted to engage an adjustable stop. The rope 13 is wound several times around a drum 94 carrying a pinion gearing with a rack 91, which is connected to the stem of the stop valve. A weighted lever 135 on the drum spindle ensures the return of the stop valve to a central position when not in operation. In another modification, the rope 13 is connected to a pivoted lever, which has a pin-and-slot connexion, with one arm of a pivoted bell-crank lever, the other arm carrying a balance weight.