US287262A

US287262A - John a

Info

Publication number: US287262A
Authority: US
Publication date: 1883-10-23
Anticipated expiration: 1900-10-23

Description

(No Model.)

J. A. EVARTS.

FRICTION BRAKE FOR ELEVATING DEVICES.

No. 287,262. Patented 001;. 23, 1883.

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UNITED STATES PATENT OFFICE.

JOHN A. EVARTS, OF MEBIDEN, CONNECTICUT, ASSIGNOR TO THE BRADLEY & HUBBARD MANUFACTURING COMPANY, OF SAME PLACE.

FRICTION-BRAKE FOR CELEVATING DEVICES.

SPECIFICATION formingpart of Letters Patent No. 287,262, dated October 23, 1883.

7 Application filed September 19,1883. (No model.)

To all whom it may concern.-

Be it known that I, JOHN A. EVARTS, of Meriden, in the county of New Haven and State of Connecticut, have invented a new Improvement in Frictional Brakes for Liftin g Devices; and I do hereby declare the following, when taken in connection with accompanying drawings and the letters of reference marked thereon, to be a full, clear, and exact description of the same, and which said drawings constitute part of this specification, and rep resent, in

Figure 1, a side view; Fig. 2, an edge view, looking from the right; Fig. 3, an edge view,

1 5 looking from the left.

This invention relates to an improvement in brakes for lifting devices, with special reference to springs, such as employed for suspending lamps and other articles which are to be held at different elevations, but is applicable to the wheels of other lifting apparatus, the object being to make the weight which is suspended serve to apply the brake; and it consists in a wheel substantially in con- 2 5 nection with the lifting-drum, and a lever having one arm to bear upon said wheel, the other arranged so that the cord or chain by which the weight is suspended will pass over said arm to the drum, and thereby cause the 0 weight of the thing suspended to bring one arm of the lever into frictional bearing upon said wheel, and as more fully hereinafter de scribed.

. In illustrating my invention I show the lift- 3 5 ing device as a common spring-drum, A. This is arranged in a suitable frame, B, provided with convenient means, C, for attaching the lifting device at any point from which suspension is desired. One edge of this drum is fitted with a wheel or flange, D. In the frame below the axis E of the wheel D a lever is hung upon a pivot or fulcrum, a. One arm, F, of this lever is fitted with a shoe or surface, I),

Y to bear upon the periphery of the wheel D.

4 5 The other arm, G, extends to the opposite side,

and is there preferably provided with an antifriction roll, (Z. The cord or chain H has one end attached to the drum, and passes from the drum overthe anti-frictional pulley d,

thence downward. To this chain the thing to be suspended is attached. Suppose, for illustration, the thing sosuspended to be a lamp. The weight of the lamp is therefore brought directly upon the arm G of the lever, tending to turn that arm downward and the other arm, F, upward against the wheel D, and thereby apply the frictional bearing-surface b of that arm to the periphery of the wheel. This frictional surface under the weight of the lamp should be sufficient to hold the lamp suspend- 6o ed at any desired point of elevation. IVhen it is desired to raise the lamp, simply lift upon the lamp sufficient to relieve the arm G from the entire weight of the lamp, and which will correspondingly reduce the friction of the other arm upon the wheel D, and permit the spring to react and wind the cord or chain upon the drum until the lifting-power applied to the lamp be removed. Then the weight again falls upon the arm G of the lever and applies the brake, as before. The friction of the arm F upon the wheel D, as before stated, is only sufficient to hold the lamp at any point of suspension, but is not so great as to resist the pulling down of the lamp, and so that when the lamp is desired at a lower elevation pulling downupon the lamp will draw the cord or chain from the drum, resisted only by the frictionof the arm F and the power of the spring, it being understood that in case of such a suspensionspring the power of the spring itself nearly counterbalances the weight of the thing suspended. Instead of a springbarrel, it may be a weight applied to a drum, which will counterbalance the fixture or thing 8 5 suspended, substantially as does the spring as before described.

I represent the lever as applied below; hence a lever of'the first order is required; but if the' lever be applied, as it may be. above, then the lever will be of the second order.

The uses for such suspending devices are numerous. The illustration as applied to a lamp will be sufficient for the full understand '9 5 ing of the invention.

Vhile I describe the, surface upon which the brake bears as a wheel, D, I do not wish to be understood to mean that such'a wheel independent of the drum is necessary, as the,

wheel may be the surface of the drum. Therefore by the term wheel I wish to be understood as-embracing any rotating surface through which lifting-power is applied.

In case of a broadfaced drum the anti-friction roll (1 should be arranged to slide on its axis from side to side, to lead the chain'or cord from the surface of'the drum. Therefore, as seen in Fig. 8, the arm G of the lever is bifurcated, with an arbor across, and the roll (1 arranged thereon.

I claim- 1. In a lifting device, the combination of a wheel arranged to revolve and, in connection with the lifting-power, a lever hung to bear upon the periphery of said wheel and JOHN A. EVARTS.

Witnesses:

F. J. SEIDENSTICKER, H. S. SAVAGE.