US403668A - Safety device for elevators - Google Patents

Description

(No Model.)

T. W. HEERMANS.

SAFETY DEVICE FOR ELEVATOES. No. 403,668. Patented May 21,1889.v

li L: lllilllllll UNITED STATES PATENT OEEICE.

THADDEUS WV. HEERMANS, OF CHICAGO, ILLINOIS, ASSIGNOR TO IHE CRANE ELEVATOR COMPANY, OF ILLINOIS.

SAFETY DEVICE FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 403,668, dated May 21, 1889.

Application filed February 9, 1889. Serial No. 299,241. (No model.)

To all whom, t may concern:

Be it known that I, THADDEUS W. HEER MANS, of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Elevators, of which the following is a specification.

My invention specially applies to that class of safety devices att-ached to the car or cage in which the catches or pawls are under ordinary circumstances kept out of action by a retaining pawl or detent, and are released and applied when the normal speed of descent of the elevator1 is exceeded.

My invention is designed to render the release of the detent certain whenever the normal speed is exceeded, and, further, to provide against accident from the breakage or derangement of the parts.

My invention consists in the parts and combinations hereinafter described and claimed.

In the accompanying drawings, Figure 1 is a side elevation of the upper cross-beam of an elevator car or cage and such portion of the safety device as is necessary to illustrate my invention. Fig. 2 is a top view of the same. Fig. 3 is a side view of the pulley carrying the detent-tripping weight. Fig. et is a central cross-section of the same and the stud upon which it turns.

A, Fig. 1, is the upper cross-beam of the elevator car or cage. To this eross-beam is pivoted a lever, B, which may be tilted by the spring C, connected thereto by a rod, D, whenever the spring C is released. The spring, rod, and lever may be adapted to operate any of the ordinary and well-known safety-catches, one form of which is shown in Letters Patent No. 313,240, of March 3, 1885, to G. H. Reynolds; but as the present invention is not concerned therewith the catches are not shown in the drawings. The detent E, engaging with a stud, F, on the rod D, serves to prevent the action of the spring and the consequent setting of the catches, except when said detent is moved so as to release the rod D. A pulley, G, is pivoted to the beam A, and a stationary rope, H, extending up and down the elevator-shaft, passes around a groove in the edge of the pulley, and also around the double= grooved pulley I, a rope being crossed between the pulleys G and I, so as to have a greater frictional surface on the pulley G. As a result of this construction, the pulley G is caused to revolge Whenever the car moves up or down in the shaft. Pivoted at N to the pulley Gis a weight, J, (shown in dotted outline in Fig. 1, and in full lines in Fig. 3, which shows the opposite face of the pulley Gfrom that shown in Fig. 1.) The pulley G is recessed in order to accommodate the weight J, the opposite side of the pulley being left thicker, so that the pulley and weight, considered as a whole, shall be balanced. This weight consists of an elongated body, which is somewhat curved in order to bring it within the circumference of the pulley G and in a more favorable position for the action of centrifugal force upon it. This curved body is recessed, as shown at M in section, Fig. 4, for the reception of a spiral spring, L. The thrust of the outer end of said spring L is received upon a set-screw, k, passing through the flange g of the pulley G. The weight J is also provided with a tongue, y', the outer end of which, as shown, projects slightly beyond the circumference of the pulley G. The tongue j is in the same plane )as the arm e of the detent E. (Vide Fig. 2.

The mechanism which the release of the detent puts in operation may be connected with a friction-brake, with a signal-bell, with the operating-valve of the engine, or with any lof the operating or regulating parts or attach ments of the engine or elevator.

The operation of the device is as follows: As the safety-catches are only intended to protect the too sudden descent of the cage, the device for tripping the detentand allow-V ing the catch-setting devices to operate is only calculated to come into use upon the descent of the cage, in which case the revolution of the pulley G is in the direction indicated by the arrow thereon. (Vide Fig. 1.) When revolving in this direction, the free end of the weight J is in advance, and when in position to release the detent E the force of gravitation is co-operating with the centrifugal force to oppose the tension of the spring L. The face of the arm e of the detent E which comes in contact with the projection j is approximately normal to the line joining the point of contact and the pivot N, (vide Fig. 1,) on Which the Weight J turns. The result is that incase the centrifugal force becomes great enough to bring the Weight J at all into contact With the arm e of the detent' E the releasing of the detent is mechanically certain, and does not depend at all upon the centrifugal force of the Weight J, for the friction between the surfaces of the projection .j and the arm e, combined with the advancing motion of the pulley G, causes the Weight J to swing on its pivot end and thereby throw the projecting tongue j still farther outward.

and as a further result, if the spring L should become relaxed or should be broken, it could not pass unnoticed, because gravitation would Y cause the weight J to swing out from the pulley and to come in Contact with the again c, and would then necessarily release the detent without the aid of any centrifugal force or mo- As, a result, the release of the d'etent E is assured,

advanced free end being adapted to make' contact with said detent when a normal speed of descent is exceeded, substantially as de scribed.

THADDEUS XV. HEERMANS.

hWitnesses:

P. H. T. MASON, O. R. BARNETT.

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