US642448A - Safety device for elevators. - Google Patents

Description

No. 642,448. Patented 1an. o, |900. J. w. HoLMEs.

SAFETY DEVICE F'OR ELEVTORS.

(Application le July 8, 1898.)

(No Model.)

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444/444 lm 1w m: ohms Pzrcns co. Mofo-LITRO., wAsHiNG'mN. nv c NITED- STATES PATENT OEEICE.

JOSEPH W. HOLMES, OF JOPLIN, MISSOURI.

SAFETY DEVICE FOR ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 642,448, dated January 30, 1900.

l Application filed J'uly 8, 1899. Serial No. 723,187. (No model.)

Missourhhave invented certain new and usev ful Improvements in Safety Devices for Elevators, of which the following is a specification.

This invention is an improvement in safety devices for elevators; andthe object of the same is to provide certain devices to positively arrest the descent of the carin the event the hoisting and lowering cables are broken or relieved of tension from any cause, the said devices being automatically and quickly thrown into operation, so as to promptly engage and support the car. To this end the invention contemplates the construction and arrangement of parts constituting the invention by which they are normally held out of operation by the weight of the car, comprising a vertically-movable beam at. the top of the elevator-shaft, carrying the pulley or pulleys over which the cables pass, springs for raising the beam when it is relieved of the weight of the car suspended by the cables, gravity-pawls arranged in vertical seriesat opposite sides of the elevator-shaft, and rods connecting the parts to the movable beam, so that they will be operated thereby, the car being provided with ratchet-plates so disposed as to be engaged by the pawls when the latter are released.

The following specification enters into a detail description of the invention, reference being had tothe accompanying drawings and to letters thereon, which designate the dierent parts, and what I claim in the construction and combination of the instrumentalities is more specically set forth in the appended claims.

In the drawings forming a part hereof, Figure 1 is an elevation showing the application of my invention, the safety devices being shown in their normal position. Fig. 2 is a similar view illustrating the disposition of the safety devices when the car is supported thereby.

With reference to said drawings, A A designate the vertical posts forming part of the elevator-shaft and arranged at opposite sides thereof, and B designates a horizontal stationary beam at the upper end of the shaft.

In carrying out my invention a horizontal beam C is mounted above the stationary beam B and is movable vertically with respect thereto, being guided by bars D D, which are secured to the end portions of the movable beam and depend through vertical openings in the stationary beam. Uponthe movable beam C centrally is secured a bracket E, adapted to support a pulley or grooved wheel F, over which the hoisting and lowering cables pass,

f said cables being designated by the refereneeletter G, and are attached atone end to the car from which they pass over the grooved wheel and extend therefrom to the motor. The weight of the car will hold the movable beam C upon the stationary beam B, and in order that the former may be moved upward when relieved of the weight of the car to operate the gravity-pawls, hereinafter described, strong helical springs I are interposed between the movable and stationary beams, encircling the guide rods or bars D to be held in place thereby.

The postsA A of the elevator-shaft are provided with recesses a at regular intervals, those in one post being preferably on the same plane with those of the other post, though this arrangement is not essential. These recesses are for the purpose of receiving pawls K, which are pivoted slightly above the base of the recesses, and are preferably' L shape, the member 7c being a little thicker and heavier than the member la and also somewhat longer. The outer end of the member lo of the pawl K is beveled, as shown, to engage the teeth of a ratchet-plate L, secured to the car. There is a ratchet-plate on each side of the car, said ratchet-plates being arranged vertically and so disposed with relation to the sets of pawls vas to be engaged thereby when said pawls are moved into the path of the ratchet-plates.

Normally the pawls are positioned with their members lo vertical and within the recess in the post, while the member 7c is substantially horizontal and projects a little beyond the rear end of the recess or beyond the outer side of the post in order that the operating rod or chain M-one for each set of pawls-may be connected to the outer ends of the members lo' and serve to throw the pawls into an operative position. The rods or chains are connected ,to the lower ends of IOO the guide-bars D, and by this connection an upward movement of the beam C, carrying the guide-bars with it, will tilt the pawls K and cause at least two of them to promptly engage the ratchet-plates on the elevator-car. The throw of the pawls is limited by the base of the recess in the posts in which said pawls are pivoted, and the strain on the pivot-pins is relieved to a considerable extent by pins N, located above said pivot-pins and adapted to be engaged by the member 7c' of the pawl.

It will be noted that when the pawl is tilted to a certain extent the member 7c will overbalance the member 7c and insure a positive action of said pawl. It will also be noted that all pawls are simultaneously thrown into an operative position or into the path of the ratchet-plates on the car by the upward movement of the movable beam supporting the cables, and thereforein the event of the breaking of any pawls those below would be in position to catch the car.

' The construction and operation of my improved safety devices for elevators are apparent from the foregoing description when taken in connection with the accompanying drawings, for the parts are normally in the position shown in Fig. l, as the cables passing over the movable beam and the car being supported thereby the weight will hold the said movable beam depressed against the action of the helical springs, and the pawls being all located within the recesses in the posts will not interfere with the running of the gage the car.

car. At the breaking of the cables the beam C is relieved of the weight of the car and is immediately lifted by the springs, and drawing upon the rods or chains M the latter will move the pawls into the path of the ratchetplates on the car. The pawls are preferably located at suoli distance apart that when they are thrown into an operative position at least two will at once engage the car, though it may be desirable in some instances to have them so arranged that at least four will en- However, in the event of the breaking of a pawl or set of pawls the car will be caught by those below. It will be seen, therefore, that I have provided a simple but effective means of arresting the fall of a car in the event of the breaking of the cables and that the operation of the safety devices is such as to be positive in action, while in their normal position the devices will not interfere with the running of the car. It is also apparent that the devices can be readily applied to any ordinary elevator shaft and car,

and being quick and automatic in action will prevent any serious accident inthe event of the breaking of the cables.

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

l. In a safety device for elevators, the combination with the elevator shaft and car, of a stationary beam, a vertically-movable beam mounted above said stationary beam, guidebars secured to the end portions of the movable beam and depending through openings in the stationary beam, helical springs encircling the guide-bars and interposed between the stationary and movable beams, pivoted pawls arranged in vert-ical series in the elevator-shaft, rods connectedto the pawls and to the guide-bars of the movable beam, and ratchet-plates secured to the sides of the car and adapted to be engaged by the pawls; the hoisting and lowering cables of the car passing over a pulley on the movable beam so that the weight of the car Will hold said beam normally depressed against the action of the helical springs, substantially as shown and for the purpose set forth.

2. In a safety device for elevators, the combination with the elevator shaft and car, of a horizontal stationary beam at the upper end of the shaft and provided with vertical holes near each end, ,a beam mounted movably `above the stationary beam, guide-bars securedto the ends of the movable beam and depending through the vertical holes of the stationary beam, helical springs encircling the guide-bars and interposed between the beams, pawls pivoted in recesses in the vertical posts of the shaft, said pawls being located or pivoted a slight distance above the base of the recesses and provided with a heavy member having a beveled end, and

rods connected to the pawls and to the lower JOSEPH WV. HOLMES.

Witnesses:

JAMES P. MEAD, J. F. OsBoRNE.

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