USRE2020E - Improved self-acting pulley-brake - Google Patents

Description

. ner that the said sheave or sheavesareal-lowed the cost of the block.

passing over it, all as usual.

` a-Ycatching round a screw, b, or other suitabl '"{UNITED STATES JoHN Jooi-tUM, 0F BR .PAT/ENT, Ormes,

oo KLYN, NEW Yonk,

. IMPaovED sELF-ACTiNG PoLLEY-BRAKE.

Specification forming part of Letters Patent No. 45,248

To all whoni, it ma, concern:

Beitknown that I, '0H N J0oHUM, of Brooklyn, in the county of Kings and State of'New York, have invented a new and Improved Self-Acting Pulley-Brake; and. 1 do hereby' declare that the following is a full, clear, and

exact description thereof, which will enable others skilled in the art to make and use the same, reference being had to the accompanying drawings, forming part of this specification,

Figure 1 represents a longitudinal vertical section ot' my invention, the line x Fig. 2, f indicating the plane of section. Fig. 2 is an end elevation of the same.- Fig. 3 is a detached view of tlie brake.

Similar letters of reference indicate like parts.

. This invention consi's an ordinary tackle-block a spherical brakeshoe attached to a. spring and applied between l the sheave or sheaves, and the shell of abloek containingone or more sheaves in such a mants in kcombining with that ataekle-bloek is obtained oi'a convenience to turn freely in one direction but prevented from revolving in the opposite direction, and

much superior to that of the ordinary tackleblock in hoisting, shortening sail, and other similar operations with a. tritling increase in i A represents the shell of a tackle-block, which is made of wood or any other suitable material in the usual manner. This block forms the bearin gs for the axle C of the sheave 1),.and it is provided with a strap, made of a piece of rope orl of metal. The sheave is grooved to form a secure guide for the rope ,My brake attachment consists of a spherical wedge, E, which is secured to aspring, F, and placed between the circumference ofthe sheave and the shell of the block, as clearly shown in the drawings.y 1f the" shell contains two or more sheaves a separate wed ge'may beapplied to each sheave, or one and the same wedge may be used for ditl'erent sheaves. lhe spring F is so adjusted; that it pulls the -wedge ll gently between the sheave and the shell, and

it is fastened to said shell by means of a hook,= e 1 fastening, so that it can be easily unhooked 'Whenever it may be brake.

desirable to remove the July 4,

, dated November 1864 g Reissue No. 2,0'20, dated It' the sheave rotates in the direction of the arrow marked on it in Fig. l, the wedge is` pushed out and the motion ot the sheaVe taker place with an imperceptible obstruction; but if an attempt is made to` turn the shea-ve in the direction opposite to the arrow marked on it, the wedge is drawn in between its eir oumference and the shell and the sheave is not allowed to move.

Thel great advantage f this arrangementl for taekleblocks is apparent. In hoisting a heavyweight with an ordinary tackle-block halt' the labor consists in holding onto 'thev rope until a fresh hold can be taken, and if two men shauhl be perfectly able to raise the weight, at least one but generally two other men are 'needed to accomplish the operation of hoisting. By the use of my 'tackle-block this extra number of men canbe dispensed with. lt' two men are able, to raise a weight,

they can also hoist it readily, because theweight once raised is not allowed to fall back except it' the rope is permitted to slide over the sheave.

In lowering a weight my tackle-block has also great advantages. The sheave, not being a over its cireumfe lto lower a comp little exertion. This tackle-block is ofparticular I.ulvantage on board of vessels for "all operations connected with raising or lowering the sails and lor any other hoisting operation.

renee,.and one man is'enabled l am well aware that a spherical brake is in I use on sewing-machines to prevent the main shaft of the same being turned in the wrong direction, but the application of such'a brak-e toa tackle-block requires a specialcontrivance to adapt it to aet'with promptness and et'ec in all positions of the block.

I do not claim, broadly, the use of aball as a brake' for pulleys; but

. vI claim as new and desi ters Patent A tackle-block containing one or more sheaves and provided with one ormore spherical wedges, 1G, and springs F,'eonstructed re to secure. by Letand opera-ting substantially as and for the purposes set forth.

.ions .ioouunt Witnesses z M. M.v Lrvr-ncsfroN,

C. L. -sPLrFF.'

llowed to turn back causes the rope to glide aratively heavy weight with.'

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