US1118776A - Controllable elevator-safety. - Google Patents

Description

C. B. ISNER.

UONTROLLABLE BLEVATQR SAFETY.

APPLICATION FILED 1111111124, 1914.

Patented NOV. 24, 1914.

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CONTROLLABLE ELEVATOR SAFETY.

APPLICATION FILED MAR. 24, 1914.

Patented Nov. 24, 1914.

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CONTROLLABLE ELEVATOR-SAFETY.

Specification of Letters Patent.

Patented Nov. 24, 1914.

Application filed March 24, 1914. Serial No. 826,841.

of which the following is a full, clear, and

exact description.

My invention relates to elevator safety stops adapted to lock the car to the guide rails when the hoisting cable breaks, and it has reference more particularly to a controllable safet'y stop whereby when the hoisting cable of the elevator is ruptured the falling car will come to a stop on the level of some one of the floors of the building in which the elevator is used.

An object of the invention is to provide a simple, reliable, strong and inex ensive means which can be controlled by he elevator governor or. by means that can be manua ly operated by the man controlling the movement of the elevator.

A further object of the invention is to provide a controllable safety stop whereby when falling the elevator is gradually brought to a stop.

The safety stop by means of which I attain the above objects is illustrated in the accompanying drawings forming a part of the specification, in which similar characters of reference ind1cate corresponding parts in all the views and wherein- Figure 1 is an elevation of an elevator partly in section equipped with an embodiment of my invention, the same being shown in inoperative position; Fig. 2 is an enlarged view of Fig. 1 showing the safety stop in operative position, the dotted lines showing the car descending gradually to a stop; Fig. 3 is a horizontal section on line 33, Fig. 1, showing the means for gradually stopping the elevator; Fig. 4 is a longitudinal section through the means for gradually stopping the elevator; Fig. 5 is an end view of the arm carrying the catch; Fig. 6 is an end view of the catch or grip, showing the enga ement of the same with the guide rails; an Fig. 7 is a perspective view of the means controlling the safety stop.

Referring to the drawings, 8 represents an elevator car provided with a hoisting cable 9 and guide rails 10 forthe car. Pivotally mounted on the top of the elevator is a pair of boll crank levers 11, the substantially horizontal arms of which are directed toward each other and at the ends thereof are provided with slots 12. A pin 13 engages the slots in said cranks and carries one end of a spring 141, the other end of the spring being engaged by a bolt 15 slidably mounted on the portion 16 ri 'dly secured to the roof of the elevator. fi iach of the other arms ofthe crank levers 11 inclines toward the adjacent guide rails 10. An open-end slot 17 is provided on said arm and therein carries a catch or grip 18. The grip 18 forms two similar parts positioned at each side of the rails 10, bridged by an integral portion 19. The extensions 20 of the grip receive there betweenthe slotted end of the bell crank lever 11. A pin 21, which unites the extensions of each of the grips, is engaged in the slot 17 and is preferably of angular cross section in the slot, so as to prevent the turnin of the grip when the safety stop is in lnoperative position, as shown in Fig. 1.

The catches 18, positioned on the opposite guide rails, are interconnected by means of cables 22, each end of each of the cables 22 being pivotally connected to a corresponding side of the catch 18. The reason for providing two cables 22 is to increase the safety, so if there is a rupture of one of the cables, the other will still support the load. The cables 22, which are made to pass under the bottom of the elevator, engage sheaves 23 and 21. The sheave 23 is connected to a plunger 25 engaging a cylinder 26 forming a part of the sheave 24. Thecylinder 26 and the sheaves 24 are rigidly secured to the under side of the bottom of the elevator; while the sheave 23, with the plunger, is movable, and their movement is guided by means provided either on the bottom of the elevator or by extensions formed from the cylinder 26.

'It will be noted that each of the cables 22 coming from the right side of the elevator structure, as shown in Figs. 1 and 2, is directed to one of the pulleys of the sheave 24, from there to a pulley of the sheave 23, back again to a pulley of the sheave 24, etc.; then from the last pulley of the sheave 24 it is conveyed to a guiding pulley 27, and from there to the grips 18 on the left side of the elevator structure. When the safety stop is in inoperative position, as shown in Fig. 1, the sheaves 23 and 24 are separated from each other, and, therefore, the plunger 25 is only slightly engagedinto the cylinder 26, which is filled with oil. The cylinder 26, at its upper end, is provided with a cup 28 which communicates with the cylinder by means of a number of very small apertures 29 extending longitudinally of the cylinder. The steps 30 which are adapted to be en gaged by the grips 18, are secured in predetermined places on the guide rails 10.

"When the hoisting cable 9 breaks, the governor rope 31, which is connected to the bolt 15, pulls the same out of the stationary portion 16 provided on the top of the elevator, releasing the spring 1%, which leaves the bell cranlrlevers 11 free to move on their pivot under the weight of the cables and grips carried by said bell crank levers 11, also due to the sudden release of said crank levers by the spring 14. This movement of the cranlr. levers throws the grips against the guide rails 10, and the same will come across the nearest stops 30 carried by'said rails, wherehythe grips l3 become station ary, while the car continues to descend under the momentum, disengaging the crank levers from the grips and forcing the plunger 25 into the cylinder 26, due to the weight applied to the cables22. The oil in the cylinder 26, due to the movement of the plunger 4 into the cylinder, is forced through the apertures 29 into the cup 23, and as the volume of the cylinder decreases, the resistance to out flow oi the oil increases, and, therefore, the gradual descent of the elevator is insured. The length of the cables 22 is such with reference to the position of the stops 30 that when the plunger has completely entered the cylinder 26 the car will be at a stop on a level. with a door of the building, thus permitting the ersons that may be in the car to escape to t e floor without ladders or other inconvenient contrivances.

'llo permit the operation of the releasing device independently of the ruptured hoisting cable 9, the bolt 15 is provided with a transverse pin 32 normally in contact with a projecting, bifurcated end of a member 33 pivotally mounted within the elevator to the roof of the same. To this member 33 a suitable, flexible connection 34 is attached, and

by pulling the said connection 34:, said bolts can be withdrawn, releasing the spring 1t independent of the controller rope, thus causing the operation of said safety stop as described. lit will be noted that by providing the relatively movable sheaves 23 and 2d, the momentum of the falling car is greatly reduced; and this momentum is still further reduced by the provision of the increased resistance to the outflow of the oil in the cylinder as the plunger approaches the limit of its movement into the cylinder. This provision of relatively movable sheaves and oil flow permits the gradual reduction of speed of the falling car, thus bringing the same gradually to a stop at a predetermined place, z'. 6,, at the level of any of the floors of the building which is provided with an elevator stop as described.

Having thus described my invention, 1 claim as new and desire to secure by Letters Patent:

1.. ln combination with an elevator car, guide rails; stops on said rails; and a safety mechanism carried by the car comprising a pair of hell crank arms, a catch suspended on each of said bell cranlr arms and adapt ed to engage the stops, means for maintain.

. ing said bell crank arms in inoperative position whereby the catches clear the stops, means for throwing said bell cranls: arms into operative position whereby the catches thrown into the path of the stops, a cable associated with said catches, relatively mov able sheaves carried by the car and engaged by said cable, a cylinder associated with one of said sheaves, a plunger carried by the other of said sheaves and engaging sai cylinder, a fluid in said cylinder, a cup associated with said cylinder, said cylinder havmeans connecting the cup with the cyl-- H1 index whereby when the plunger moves therelnto the hard is gradually displaced into the cup, and vice versa, said catches be mg adapted to detach from said cranlr levers when engaging said stops, whereby said sheaves are caused to move toward each other under the weight of the car and the fluid in the cylinder is displaced into the cup, said means connecting the cup with the cylinder resisting the flow of the fluid from the cylinder into the cu directly in ropor plunger into the torn.

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said fluid operable mechanism including means for ofiering an increasing resistance as said mechanism shortens.

3. In combination with guide rails, a sto mechanism carried by the car catches adapted to, engage the stops, the catches being adapted to be detached from the car when engaging the stops, a cylinder containing fluid associated with the car, a, plunger in said cylinder, a receptacle, saidcylinder having means connectln the receptacle with the cylinder where y when the plunger moves therein the fluid an elevator car,- on said rails, a safetyf comprising nae gradually displaced into the receptacle, to this specification in the presence of two and vice versa, and a flexible member subscribing witnesses. connecting said catches to the cylinder and CHARLES B ISNER plunger, said cylinder and plunger being 5 adapted to move toward each other when Witnesses:

said catches engage the stop. BENEDICT JOFFE,

In witness whereof I have signed my name PHILIP D. ROLLHAUS.

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