US792208A - Automatic safety device for elevators. - Google Patents

Description

PATEN'I'ED JUNE 13, 1905.

J. A. GRAY. AUTOMATIC SAFETY DEVICE EUR ELEVATORS.

APPLICATION FILED PR. 4. MODEL. A 27 190 ,fle l No. 792,2os.

UNITED STATES i Patented June 13, 1905.

PATENT OFFICE.

.AUTOMATIC sAFgTYpEvlcE Fon ELEvAToFzsl SPECIFICATION forming part of Letters Patent No. 792,208, dated June 13, 1905. Applicationiiled April 2l7, 1904. Serial No. 205,101. (Model.)

To all wil/0m, t may concern:

Be it known that I, JOHN A. GRAY, a citizen of the United States, residing at Allegheny, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Automatic Safety Devices for Elevators, of which improvement the following is a specification.

This invention relates to an improved automatic safety-clutch for elevator-cars, the object being to provide a self-acting device simple in construction that may be arranged in connection with any style of an elevator-car, that will instantaneously stop the same should the hoisting-rope break; and it consists in surrounding the car with a spring-actuated frame carrying clamping-levers adapted to engage with the guide-rails in the elevator shaft or well and hold said car stationary, together with the certain details of construction and combination of parts, as will be fully described hereinafter.

In the accompanying drawings, Figure 1 is a front elevation of an elevator-car provided with my improved automatic safety-clutch, the same being constructed and arranged in accordance with my invention. Fig. 2 is a sectional plan view of the same, the said section being' taken on the line X X of Fig. 1. Fig. 3 is a side elevation of the car and device. Fig. 4 is a plan view of the top portion of the frame surrounding the elevator-car. Fig. 5 is a sectional plan view of the base ot the same.

To put my invention into practice, and thereby provide means for instantly stopping an elevator car should the rope accidentally break, the said car beingl suitably mounted within an elevator-shaft 3 and operated between vertically-arranged guides 2, to which said car is loosely attached by shoes 4 and elevated and lowered by a rope 5 passing over sheaves 8, mounted on supports at the top of the shaft in a manner well known in the art, I construct a frame about the said car 1, consisting of a platform or base portion 9, rectangular in form, to the ends of which vertical beams 1l are firmly connected, the said beams extending upward above the top level of the car 1 and fitted with a cross-piece 13.

This cross-piece is formed with a central oriiice 15, through which the operating-rope 5 passes, and at either side of said orifice with openings 14., through which two stout guidepins 16 operate, the said pins being firmly attached to the top of the elevator-car 1 and are surrounded by spiral springs 17', which bear against the cross-bar 13 and tend to thrust the frame upward.

Arranged at each end of the base portion 9 of the frame and at each side of the two guides 2 are clamp-levers, each of which consists of a strong metal bar 17, pivoted by a bolt 18 in a position that will permit the inner end to take a frictional hold upon one of said guides 2, and the outer end formed with a slot 21, which by means of a pin 20 aords a means of connection with the base 12 of the car 1 in a manner that when the said car is given a slight upward movement the outer ends of the clamp-bars are carried upward, thereby removing the inner or clamp ends away from the guide-rails 2, the inner ends of the clampbars being curved on lines eccentric to their pivotal points.

In operation the car 1 is suspended and operated by the rope 5, the springs 17 being compressed by the weight of the frame. Should the rope 5 accidentally break, the car 1 drops by gravity and takes the position shown in the several views of the drawings, the movement of the frame being retarded for an instant, caused by the action of the springs 17', increasing the space between the said car and the top of the frame. During this momentary stop the outer ends of the clamps 17 are depressed, causing the inner extremities of the same to engage with the guide-rails 2, and it is obvious that by this construction and arrangement the greater the weight of the car and its contents the greater will be the hold of the clamps upon the guiderails, and the weight of the car Will therefore render the car immovable. To release the car from this position, it is only necessary to connect the car 1 to the rope 5 and elevate the said car slightly or to the position shown in dotted lines at Fig. 1 of the drawings. This movement of the car within the frame carries the outer ends of the clamp-levers 17 upward, separating the same from contact with the guide-rails 2.

It will be seen by the above description, taken in connection with the accompanying drawings, that the operation of stopping the car is instantaneous and automatic and will eifectually prevent the car from falling in case of an accident to the lifting-rope 5.

It will be readily understood that by slight modications this device may be adapted for use upon the cars of inclined railWays,Where the said cars are hauled up and let down steep grades by the use of cables, in which case the clamps would engage with the rails of the track, and it is also obvious that various slight modifications and changes may be made in the details of construction without departing from the spirit of the invention. Therefore I do not wish to confine myself to that shown and described.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

1. An automatic safety device for elevators comprising in combination with an elevatorcar, a movable frame, springs arranged on top of the car between the ear and the movable frame, slotted clutch-bars mounted on said frame, pins on the car working in the slots in said clutch-bars, the inner clutching surface of said clutch-bars being formed eccentric to the pivotal axis of the same.

2. An automatic safety device for elevatorcars, comprising the frame in which the said car is suspended, the guide-pins 16 connecting the top of the car with the frame, the interposed springs v17 the clamp-bars attached to the frame and arranged in pairs at opposite sides of the guide-rails 2, each of which consists of a bar 17, pivoted bya holt 18, and provided with a Slot 21, whereby connection is made with the car by means of a suitable pin 20, all arranged and combined for service, substantially as and for the purpose described.

In testimony whereof l have hereunto signed my name in the presence of two subscribing witnesses.

JOHN A. GRAY. in presence of# C. C. LEE, C. A. RoBB.

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