US1873829A

US1873829A - Elevator car safety device

Info

Publication number: US1873829A
Application number: US473915A
Authority: US
Inventors: Dunlop James
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1930-08-08
Filing date: 1930-08-08
Publication date: 1932-08-23
Anticipated expiration: 1949-08-23

Description

Aug. 23, 1932. J. DUNLQP ELEVATOR CAR SAFETY DEVICE Filed Aug. 8, 1930 INVENTOR James Dun/op TTO'RNEY Patented Aug. 23, 1932 UNITED S ATES DUNLor, F PARK RIDGE, ILLINOIS, ASSIGNOR To wEsirInGrIo sE ELEoTBIo &

JAMES ATENT oFF cE v MANUFACTURING COMPANY, A CORPORATION GF BENNSYLVAHIA ELEVATOR CAR SAFETY'DEVICE Application filed August a, 1930. 7 Serial No. 473,915

My invention pertains to safety devices for elevators and more specifically to means for setting car safety devices even though the governor cable breaks when the governor jaws set. Y

In a very high-rise elevator installation, the weight of the'governor cable is sufficient to place a considerable strain upon itself.-

In such installations, theadditional strain 10 placed upon the cable, when the governor gripped by the governor jaws, the-safety de vice, may be suflicient to cause the rupture thereof. If the cable breaks when it is vice will not be applied in such systems since it is the pull on the governor cable effected by the cable-gripping jaws which unreels the safety cable and sets the safetydevice.

It is, accordingly, also an object of my invention to provide means which, when actuated, will apply the car-safety device independently of the governor cable.

A further object of my invention is to provide means which, having been actuated by a preliminary tensioning of the governor cable, will apply the usual car-safety device independently of the continuation of the tensioned condition of the cable.

In accordance with my invention, I will provide a small roll-catch device which is associated with the governor cable and releasably carried by the car. A safety actuator cable is connected between thecar-safety device and the roll-catch device. In the event of breakage of the cable, the roll catch will lock itself to the guide rail, and the continued downward movement of the car will pull the safety actuator cable taut and apply the car safety device.

The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment, when read in conjunction with the accompanying drawing in which:

Figure 1 is a diagrammatic view of an elevator system provided with asafety operat; ing device in accordance with my invention,

aws grip it in applying the car-safety de- Fig. 2 is an enlargedsectional view, takenon line II'II of Fig. 1, and;

Fig. 3 is an enlarged sectional view of the minnie ball.

The apparatus shown in Fig. 1 comprises an elevator car C supportedby hoist cables Gain a well known manner. The hoist cables sheave l2at the top of the hatchway and underan idler sheave 13 at the bottom of the hatchway. The governor cable 11 carries a minnie ball 14, the details of which are shown 'in Fig. 3. 'A bracket 16, of any suitable shape, may be mounted on the car G to support a-releasable spring clip 18. The spring clip 18 normally holds the minnie, ball 14 with sufficient tension to pull the associated governor. cable up and down the hatchway in accordance with the movements of the elevator car.

Associated with the sheave 12 is a governor 20 which is driven thereby at speeds proportional to the speed of the elevator car as it passes up and down the shaft. A pair of cable-gripping 2-1 and 22 arepivotally mounted on opposite sides of the governor cable 11 where it passesfrom'one side of the sheave 12. The jaws are provided'with camformed cable-gripping surfaces which will grip and lock; the adjacent cable if turned into contact therewith when it is moving downward. Through a pivoted lever 23 and a link member 24, the governor 20 may actuate the cable-gripping jaws 21 and 22 to gripping position when the elevator car moves at a predetermined excessive speed-{1 The spe cific governoncable-gripping j aws, actuating mechanism and sheave used are immaterial andinay be any specific structure well known intheart. x v A car-safety braking device30, carried by in any suitable manner.

the car C, comprises any well known carsafety device of the type having a cable drum and jaws 31 actuated by unreeling the cable for gripping the guide rails and applying a braking force to retard the car when a safety cable 32 is unreeled from the safety drum. The structural details of the safety device are not shown since any well known safety device may be used, such for example as that disclosed in my prior patent No. 1,598,065.

Ordinarily, the safety actuating cable 32 would be connected directly to the governor cable 11 by the minnie ball 14,'whereby the downward movement of the car, after the cable 11 is locked by the jaws 21 and 22, would unreel the cable 32 from the safety drum and apply the safety device. This method of operating the safety device places an additional strain on the governor cable 11 which may be suflicient. to break that cable in highrise installations where the weight of the cable is itself suificient to cause considerable strain at all times. It will be apparent that, when the governor cable breaks in such systems, the car safety device'will not be applied.

In accordance with my invention, a small roll catch 35 is connected to the safety actuating cable 32, and the roll 36 thereof is connected, by a bail 37 and a cable 38, to the governor cable 11, as clearly shown in Fig. 2. The roll 36 may be of hardened steel provided with a knurled surface that will bite into the surface of the guide rail 2 when lifted into contact therewith by the cable 38. The roll is received by a recess 39 in the body of the device 35 where it normally rests in spaced relation from the web of the guide rail 2, as shown in Fig. 2. The upper surface of the recess 39 is inclined toward the rail in such manner that the roll will be forced into contact with the rail when it is lifted. The in clination of the upper surface of the recess 39 toward the rail 2 is also effective to force the roll 36 into closer engagement with the guide rail, as the car continues downward.

The roll-catch device 35 is releasably mounted on the car C above the guide shoe A As shown in Fig. 1, the roll-catch device 35 is supported on a bracket 41 that is slidably received by the bracket '7 which supports the guide shoe 4.

In Fig. 3, I have shown the specific structure of the minnie ball 14 which is carried by the governor cable 11 for detachably securing the latter to the spring clip 18. The minnie ball comprises two halves bolted together. As shown in Fig. 3, the inner surface of one half of the minnie ball is ex posed, the other half thereof having been removed. The inner surface of each half of the ball is provided with a groove which receives the cable 11. A second groove is provided for receiving the cable 38. In order to increase the friction of contact of the cable with the minnie ball, the grooves may be curved from side to side rather than straight. The second half of the minnie ball is provided with identical grooves, and, when the two parts of the ball are bolted together, the cables will be clamped into the grooves. The minnie ball 14 serves not only as a button tobe releasably received in the spring clip 18 but also as a clamp for attaching cable 38 to cable 11.

My invention is best understood, however, when considered with reference to an assumed operation thereof. Assuming, for example, that the car, when traveling down the hatchway, attains an objectionable degree of overspeed, the governor 20 will actuate the jaws 21 and 22 to cable-gripping position. The jaws will grip the cable 11 with suflicient force to pull the minnie ball 14: from the spring clip 18, and the continued downward motion of the car will draw the cable 38 taut, thereby lifting the roll 36 into engagement with the guide rail 2. As the roll 36 bites into the rail 2, the continued downward movement of the car will cause the inclined upper surface of the recess 39 to force the roll into closer engagement with the rail until the roll-catch device 35 grips the rail with sufiicient force to pull away from the bracket 7 by which it was releasably mounted on the car. The roll-catch device 35 will continue to grip the rail 2, even though the governor cable 11 becomes ruptured. Since one end of the cable 32 is attached to the roll-catch device 35, the downward movement of the car will then cause the cable 32 to be unreeled from the cable drum of safety device 30, thereby setting the car safety jaws 31 to grip the guide rails and stop the car.

It will be seen, therefore, that I have provided a safety actuating device for elevators wherein the downward motion of the car itself is utilized to unreel the safety cable and set the safety device, irrespective of the condition of the governor cable after it has been gripped by the governor jaws to initiate the operation of the device.

Although I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim as my invention 1. In combination, an elevator car, a safety 1i braking device for retarding the car, means operably responsive to a predetermined speed of the car, actuating means operated thereby for applying said safety braking device to retard the car in the eventthat the speed thereof becomes excessive, and means mounts ed detachably on the car for separating therefrom and completing the application of said safety device, said means being responsive to an initial operation of said speedresponsive device even though the initial actuating force is not maintained.

3. In combination, an elevator car, a safety braking device for retarding the car, speedresponsive means operable at speeds corresponding to the speed of the car, actuating means operable thereby at apredetermined speed of the car for rendering the movement of the car effective for applying said safety braking device to retard the car in the event that the speed thereof becomes excessive, and additional actuating means whereby the continued movement of the car is rendered effective to complete the application of the car safety device even though the first actuating means becomes inoperative after its initial operation.

4:. In combination with an elevator system comprising an elevator car operable up and down a hatchway between guide rails, a safety braking device carried by the car and actuable by unreeling a cable for gripping the guide rails to stop the car, an overspeed governor, a cable associated therewith for actuating said safety device when the car travels at an excessive speed, and means mounted detachably on the car for completing the application of the safety device even if the governor cable is ruptured by the initial operation thereof.

5. In combination with an elevator system comprising an elevator car operable up and down a hatchway between guide rails, a safety braking device carried by the car for gripping the guide rails to stop the car, a safety actuating cable, an overspeed governor and cable associated therewith for actuating said safety device when the car travels at an excessive I speed, and means for completing the application of the safety device even if the governor cable is ruptured by the initial operation, said means comprising means for clamping the safety actuating cable to the guide rail.

6. In combination with an elevator system comprising an elevator car operable up and down a hatchway between guide rails, a'safety breaking device carried by the car for gripping the guide rails to stop the car, a safety actuating cable associated with the safety device, a roll-catch device connected to said safety actuating cable and detachably mounted on the car in position for clamping the guide rail when actuated, a speed-responsive device operable in accordance with the speed of the car, and actuating means controlled thereby at a predetermined car speed for operating the roll-catch device to clamp the safety cable to the guide rail, whereby continued movement of the elevator car will actuate the car-safety device.

7 A safety mechanism for an elevator car operable between guide rails comprising a common safety braking device for gripping the guide rails to stop the car, an overspeed governor, a cable associated therewith for actuating said safety device when the car travels at an excessive speed, and means comprising a roll catch device separate from the safety device for completing the application of the safety device even if the governor cable is ruptured by the initial operation thereof.

In testimony whereof, I have hereunto subscribed my name this31st day. of July, 1930. JAMES DUNLOP.