US1870217A - Safety device - Google Patents

Description

Aug. 9, 1932. "F. BAUMGARTNER SAFETY DEVI C E Filed March 15. 1931 3 Sheets-Sheet 1 7H V E N T O R free Baum gariherj AT'TORNEY Aug. 9, 1932. F. BAUMGARTNER SAFETY DEVICE Filed March 15, 1931 3 Sheets-Sheet 2 ATTORNEY Patented Aug. 9, 1932 PATENT ()FFICE FRED BAUMGARTNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO WESTINGHOUSE ELECTRIC ELEVATOR COMPANY, A CORPORATION OF ILLINOIS Y SAFETY DEVICE Application filed March 13, 1931.

My invention relates to safety-systems for elevators and more specifically to terminal slow-down devices for automatically insur not effective to prevent a car from approach-- ing its terminal at full normal speed.

As a car approaches a terminal, its speed must be reduced below the normal full speed or the control system will be unable to stop the car when it arrives at the terminal. This is of special importance in high-speed elevator systems, of which an increasing number are being installed, and it is in connection with such elevators that my invention is of particular importance and utility.

It is, accordingly, an object of my invention to provide means for automatically stopping an elevator car if it approaches its terminal at an excessive rate of speed.

It'is also an object of my invention to provide a safety device which may be used in conjunction with, or supplemental to, the terminal slow-down devices and limit switches which are usually provided in elevator systems.

A further object of my invention is to provide means for reducing the speed adjustment of the usual overspeed governor as the elevator car traverses a portionof its path, whereby the governor will become efiective to set the safety devices if the car speed is not correspondingly diminished.

More specifically stated, it is an object of my invention to provide means which are.

movable in accordance with the movements of the elevator car for varying the speed adjustment of the usual overspeed governor in accordance with the position of the car in the hatchway, to insure the proper slow-down of the car as it approaches its limits of travel.

According to one form of my invention, 1

Serial No. 522,446.

mount a cam on the car or counterweight and a cooperative eng'ageable member'at a fixed position in the hatchway. Suitable actuating mechanism extends from the engageable member to the usual overspeed governor for varying the speed adjustment when the engageable member is actuated by the cam.

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 specific embodiments thereof, when read in conjunction with the accompanying drawings in which;

Figure 1 is a diagrammatic side elevational view showing an elevator safety system arranged in accordance with my invention;

Fig. 2 is a enlarged side-elevational view of the cam and the engageable member in cooperative relation to the overspeed governor, and speed-regulating means associated therewith; and

Fig. 3 is a side-elevational view similar to Fig. 2 but showing a modified embodiment of my invention.

Referring more specifically to the drawings, the apparatus shown in Fig. 1 comprises an elevator car C suspended by a hoist cable Ca passing around a hoist drum 11 and an idler sheave 12 to a counterweight (EV T in the usual manner. The hoist drum 11 may be driven by any conventional hoist mot-or controlled by any well known control system (not shown). The system for actuating and controlling the hoist drum is not shown because many suitable systems are well known and such illustration would unnecessarily encumber the disclosure.

A terminal rail 13 may be provided for engaging a terminal slow-down device 14; on the 'car to interrupt the control circuits in any well known manner. A bufier 15 is usually provided for retardingv the car in the event that the other slow-down devices fail when the car approaches its limits of travel;

A governor rope 16 passes over a governor sheave 17 at the top of the hatchway and under an idler sheave 18 at the bottom of the hatchway. The governor rope carries a minnie ball 19 which is releasably received.

the safety drum 25, around a pair of deflecting sheaves 26, and is attached to the governor rope 16 by means of the minnie ball 19, which thereby serves a dual purpose.

Pivotally mounted on opposite sides of the governor rope 16 are a pair of rope-gripping jaws 31 and 32' which may be moved to rope-grippingposition. by the overspeed' governor 22 when the car overspecds.

As shown more clearly in Fig. 2, a spiral spring'33 continuously biases the aws to ropegrrpping' position, and, for this purpose, one

end of the spring is hooked around a clutch lever 34 which extends laterally from one of the jaws 31. The other endof the spring 3-3 is anchored on a"- ilxed pivot The lever 34 is secured to the shaft on which the jaw is pivotally mounted and is provided with a slight cam projection on the left'hand side of the urmer end. A roller stop 36 normally engages and rcstrai'ns the clutch lever 34 to hold thejaws in their ineffective positions in opposition tothe biasing spring The rollerstop' 36 is supported on a bracket 37 which is carried ,by an actuator, bar 38; The upper end of'the actuator bar 38 is provided with a slot 39 which receives a pin 41,

projecting from the free end of governor lever 42, in order to provide a lost-motion connection between the actuator bar and the governor. The otherend of the lever 12 is anchored to a fixed pivot 43 by a link 44. The lower'end of the actuator bar 38 is pivotally connected to a guide link 45, the other end of which is pivotally secured to any fixed pivot, such as the aw shaft. The guide link 45- serves merely to guide the movements of the actuator bar 38 as it is actuated by the governor 22.

As the governor 22 is driven at increasing speeds, the free end of the governor lever 42 is elevated, thereby raising the actuator bar 38 and the roller stop 36 until the latter is above the end of the clutch lever 34. After the levcr 34 is released, the biasing spring 33 then rotates it in a counterclockwise direc tion, and the associated jaws are carried into engagement with the governor rope 16.

In order to render the device quick-acting, after a predetermined degree of overspeed has been attained, the pivot shaft of the roller stop 36 is supported in a slot M in the bracket 37. The cam projection on the upper end of the lever 34, aided by gravity, will normally hold the roller pivot in its lowermostposition in the slot 47. However, as the roller 36 spring 33 will cause it to be suddenly snapped upward, and the lever 34 will be quickly released to apply the safety device.

The apparatus described above is efiective to operate the car safety device 23' and stop the car C if it overspeeds in the hatchway for any reason. The governor 22 is provided with a suitable spring 48' the tension of which may be adjusted to predetermine the speed characteristics thereof. As the spring tension is increased, the tripping speed of the governor is increased, and it may be adjusted to permit the car to traverse the intermediate portions of hatchway at its-maximum allowable speed.

In order that the operation of the ropegripping jawsmay also be influenced according to the position of theca'r in the hatchway, I provide an actuator lever 51 pivotally mounted on a fixed pivot 52. One end of the actuator lever passes under a pin 53 which projects from theside of the actuator bar 38 and thereby normally supports the latter. A compression spring 54 is disposed adjacent to the opposite end of the actuator lever 51 and is of suflicient strength to depress the same, thereby elevating the actuator bar 38 and tripping the jaws to rope-gripping position. The pin-and-slot connection, provided on the upper end of the actuator bar 38, permitsits operation independently of the governor 22.

A rope or other flexible connecting member 61 extends from the end of the actuator lever 51 adjacent to the compressionspring 54, around suitable deflecting pulleys 62, to a triple lever 63 which ismounted on a fixed pivot 64 adjacent to the hatchway. Two arms of the triple lever carry rollers 6'5-which extend into the hatchway. The third arm 71 extends away from the hatch-way, between a pair of rigid stop members 72, and is pivotally connected to a'toggle member 73 which extends slidably through a pivoted guide 74. concentrically disposed on the toggle member 73, in abutting relation to the pivoted guide member 74, is a compression spring 75 which applies a biasingforce to rocli the lever 71 into abutting engagement wit-h the one or the other of the stop members 72. If the lever arm 71 is moved beyond its center position in either direction, the bi-asings ring 5 will move the arm into abutting relation to the nearest adjacent stop member 72. As shown in the drawings, a pair of biasing springs 7 5 may be provided for safety.

The position of the triple lever 63, as shown in Figs. 1 and 2, is that normally occupied by the device when the car is traversing intermediate portions of the hatchway. In this position, the rope 61 is drawn around the idler pulleys 62 to lift the actuator lever 51 upwardly in opposition to its compression biasing spring 54. I

A cam 81 is mounted on the counterweight- CWT and is so disposed that, if the car C approaches within a certain distance 6' of the end of the hatchway, the cam will engage the upper'roller on the triple lever 63, thereby rocking it to its second position, with the arm 71 abutting the lower stop member 72. As the triple lever rocks to its second position, it slackens the rope 61, and the compression spring 5 1 depresses the end of the adjacent actuator lever 51, thereby lifting the actuator bar 38, tripping the jaws and applying the safety device. By properly positioning the cam 81 on the counterweight and the triple lever in the hatchway, the distance 5 from the bufier 15 may be made equal to the distance through which the car will travel from the time when thetriple-lever device is actuated to the time when the car will come to a stop by the application of its safety device when traveling at full speed.

It is desired, however, to permit the car to approach the end of its hatchway if its speed is, properly diminished. F or this purpose, a latch 84 is pivoted below the end of the actuator lever 51, and an adjustable rod 85 extends from the latch 84 to the end of the governor lever 42. As the speed of the governor 22 decreases, the free end of the governor lever 42 will be lowered, thereby rotat- U ing the latch 84 in a clockwise direction. By

means of a turnbuckle 86, the length of the rod 85 may be so adjusted that, when the car is moving at a slow speed, suitable for safely approaching the terminal, the upper end of the latch 84 will be interposed in obstructing position beneath the end of the lever 51'.

hen the cam 81 on the counterweight engages the triple lever 63, thereby slackening the rope 61, the actuation of the safety device will be prevented if the speed of the car has been so diminished that the latch 84 is in obstructing position beneath the lever 51.

The actuator bar 51 has a downwardly directed nose or hook projection at its end,

designated by line X-X in Fig. 1 consider-' ably faster when approaching it from below than when normally approaching it from above. When the car is below position X-X the lever '51 is forced upon the latch 84 by the spring 54, assuming that the latch was under the lever at the instant when the car passed through position XX. However, when the car approaches the position X-X from above, the lever 51 being lifted off the latch 84: as long as the car is above this position, the latch can move in and out freely.

My invention is most readily understood, however, when considered with reference to an assumed operation thereof. Assume that the car C is traveling down the hatchway at a normal rate of speed. The governor rope 16 is moving with the car and driving the governor 22 at corresponding speeds. If, for any reason, the speed of the car increases to an excessive rate above the normal speed, the governor 22 will lift the governor lever 12, thereby raising the actuator bar 88 high enough to trip the jaws 31 and 32 to rope-, engaging position. After the jaws grip the rope 16, the minnie ball 19 pulls free from the spring clip 21 on the car C, and the con tinued downward movement of the car unreels the safety cable 2% from the safety drum 25. The consequent rotation of the safety drum applies the safety device to grip the guide rails and stop the car in a well known manner.-

Assume, however, that, as the car travels down the hatchway, it maintains a normal speed and its safety device is not set, but that, for some reason, the speed of the car is not reduced as it approaches the terminal and the usual electrical slow-down devices have failed to operate. hen the car arrives at the position X-X, the cam 81 on the counterweight ClVT will actuate the triple lever 63-from the position shown in Figs. 1 and to a second position wherein the arm 71 is in abutting relation to the lower stop member 72. As aresult of this operation, the rope 61 is slackened, thereby releasing the actuator lever 51 which is depressed by its spring 54. The other end of the actuator lever 51 is elevated to engage the pin 58, thereby lifting the actuator bar 38, tripping the rope-gripping jaws 81 and 32 to grip the governor rope 16 and set the safety device 23 on the car.

If the speed of the car is properly reduced, as it approaches its terminal, the operation of the car safety device will be prevented as follows. As the speed of the car decreases, the governor 22 causes the free end of the lever 12 to descend, thereby rotating the latch 84 in a clockwise direction by means of the rod 85 which is connected thereto. By means of the turn-buckle 86, the length of the rod 85 is so adjusted that, when the car speed is reduced to a speed which is safe for approaching the terminal, the latch 84 will be turned to obstructing position under the lever 51. Therefore, when the car passes the position XX in the hatchway, and the cam 81 on the counterweight rocks the triple lever 63 to its second position, thereby slackening the rope 61, the ensuing depression of the I intermediate point.

this form of my invention, shown in Fig. 3, a governor lever 92 is anchored to a fixed pivot 93 by a link member 94. The anchor link 94 pivotally joins the lever 92 at an Extending from the free end of the governor lever 92, on the .opposite side of the governor 22, is an actuator bar 95 which is adapted to be connected to any conventional rope-gripping jaws 96 and 97. The jaws are adapted to be tripped to rope-gripping positions when the bar 95 is lifted,

The end of the governor lever 92, which extends to the left of the anchor link 94, is

connected to the triple lever by a slender rod 98 which passes through an opening in the end of the governor lever 92 and is pivotally connected to the arm 71 ofthe triple lever.

' A compression spring 101 is concentrically disposed on the end of the rod 98 which extends through the governor lever and is adjustably tcnsioned against the end of the lever by a suitable washer 102 and nuts 103 thread ed on the rod.

The triple-lever device is identical with that disclosed in Figs. 1 and 2 and is actuable into, abutting relation with the one or the other of two stationary stop members 72 by a cam 81 carried by the counterweight, in

the manner previously set forth. As the car approaches its lower terminal, the cam 81 on the counterweight engages a roller on the triple-lever device 63, thereby throwing it to its second position,wherein the arm 71'is held in contact with the lower stop 72 by the toggle springs 75. The arm 71 draws the rod 98 down and compresses the spring 101 on the end of the governor lever 92, thereby applying a biasing force which tends to tilt it to the safety actuatingposition. Increasing the tension on the governor spring 48 tends to raise the tripping speed of the governor, but it will be apparent that an increase of tension on the biasing spring 101 tends tolower the tripping 5 speed, since it is applied to the governor lever 92 at a pointwhich is on the opposite side of the anchor link 94. Hence, the device operates to automatically readjust the speed characteristics of the governor. By manually ad-' tain specific embodiments of myinvention, I

am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restrlcted except insofar as tion for varying the speed adjustment of the overspeed governor.

"2. In combination, an elevator car, a safety-braking device carried by the car, an overspeed governor, means operated by the gover nor for applying 'the'safety-braking device when the car overspeeds at anytime, means for applying a biasing force tending to move said first means to its brake-applying u 1 tion, and means'responsive to the move t of the car in the hatchway for increasing said biasing force when the car approaches a terminal- I 3. In combination, an elevator car, a safety-braking device carried by the car, an overspeed governor for actuating the safety-braking device when the oaroverspeeds, a counterweight, an engaging member carried by the counterweight, an engageable member mounted in the hatchway and means actuated by the engagement of said members for reducing the tripping speed of the governor, whereby the safety-braking device will be appliedto automatically retard the car if it approaches the terminal at a rate of speed which is inexc ess of the said reduced rate.

4. In an overspeed governor for elevators, aspeed-responsive device, an adjustable biasing means opposing the operation of the speed-iesponsive device, whereby its normal operating characteristics may be predetermined, a second adjustable biasing means aiding the operation of the speedfresponsive device, and means adapted to vary the intensity of the second biasing means in accordance with the position of an elevator car.

'5. In combination, an elevator car, a safety-braking device carried thereby, a speedrespon'sive device-for actuating the safetybraking device when the car overspeeds, means responsive to the approach of the car adjacent to a terminal for actuating said safety-braking device, and means actuated by said speed-responsive device'for preventing the operation of said first means if the car speed is less than a predetermined rate as'it approachesthe terminal.

6. In combination, an elevator car, a brake carried thereby, a speed-responsive device, means actuated thereby for applying said brake when the car overspeeds, means responsive to the approach of a car adjacent to a terminal for independently actuating said brake, and a latch movable by said speedresponsive device to obstructing position to obstruct the operation of said second means if the car speed is properly reduced as it approaches the terminal.

In testimony whereof, I have hereunto subscribed my name this 6th day of March, 1931.

FRED BAUMGARTNER.

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