US267954A - Pullet block - Google Patents

Description

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T.- H.. WARD.

PULLBY BLOCK. l 1T0.267,954. Patented NOV. 21, 1882.

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PULLEY BLOG-K.

210,267,954; Patented Nov. 21, 1282.

NITED STATESv PATENT OFFICE.

PU LLEY-BLOCK.

SPECIFICATION forming' part of Letters Patent No. 267,954, dated November 21, 18492.l

Application tiled July 3, 1882.

To all whom it may concern Be it known that I, THOMAS HENRY WARD, (of the firm of HOWL, WARD & HOWL,) a subject ofthe Queen of GreatBritain andvlreland, and residing at Tipton, in the county of Stafford, England, have invented certain Improvements in Pulley-Blocks, parts of which improvemen ts are also applicable to cranes, overhead travelers, hoists, and other like receptacles, (for which I have obtained a patent in Great Britain, No. 5,311, dated th December, 1881,) of which the following is aspecication.

My invention relates to improvements in dit'- ferential pulley-blocks ofthe description known as Westons,7 parts of which are also applicable to certain other kinds ot pulley-blocks, and has reference partly to a former invention for which British Letters Patent were granted to myself and Edmund Howl, dated the 17th September, 1881, No. 4,012, in that the subject-matter of that patent may be. used in combination with pulley-blocks provided with my present improvements. f'

According to one part ot' my present invention, which applies toWestons pulley-blocks, I invert the arrangement of the said blocksthat is to say, I place the single sheave at the top and the differential sheaves at the bottom. It will be seen, therefore, that the single sheave will form the fulcrum, and that the differential sheaves will rise and fall as a Westons bottom sheave. I guide the chain, after it has passed over the top sheave and partly round one of the differential sheaves, down the opposite side and up again onto the other difterential sheave by means of guide-wheels, or, what is equally as well, down and up guidepieces, and allow it to hang loosely near the ground, as a loop forming an endless chain. It will be seen that this loop remains in the same' position-that is, the chain itself will neither rise nor fall bodily, and also that there are two lines only ofchain, instead of fourlines of chain, having two loops rising and falling, and that there is thus less liability of the chain becoming entangled. The block may beoperated from the chain direct, or by rotating the top sheave or the bottom sheaves by means of a sprocket-wheel or ratchet-lever, or equiva- 5o lent devices.

Figure l of the accompanying drawings rep- (No model.) Patented in England December 5, 1881, No. 5,311.

resents in side elevation, and Fig. 2 in transverse vertical section, a pulley-block constructed or arranged according to my invention.

The single sheaveat top is marked A, and its suspending-shackle is marked ot. The dii'- ferential sheaves at bottom are marked B and C, and the shackle for suspending the load is marked d. In Fig. l the differential sheaves are shown in section, one-half ot' the section being taken on a line through the one sheave and the other hall': through the other sheave. The chain E is passed partly around the one sheave of the differential sheaves, then over the upper sheave, A, and partly around the other sheave of the differential sheaves. The said chain, at the part which forms the loop extending below the bottom sheaves, is guided so as to keep the chain in gear with the sheaves by means either of rollers or guiding-surfaces. In the-drawings Ihave shown guiding-surfaces as beingemployed. They consistoi` two curved horn-pieces, f, carried byrthe cross-piece d2 of the lower shackle, d. These guiding-pieces are shown separately drawn to a larger scale in side view and plan, respectively, in Figs. 3 and 4. The cross-pinsf2 are to prevent the chain E from getting out of place. It will be seen that rollers can take the place ofthe gnidesf, if desired, and that by this arrangement of the pulley-block the chain E is not liable to be-A come entangled, and that a large saving is made in the quantity of such chain required.

Another part of m y invention relates to the gearing of blocks in order to obtain greater purchase.

In lieu ot' driving the differential sheaves by means of inside or outside spur-gear, I drive them by means of endless-chain gear. For this purpose there is cast in one or more sheaves underneath the toothed bed or groove for thel main chain another toothed bed or groove for receiving a much smaller endless chain. This chain, after passing around this additional bed or groove, passes over a corresponding chainpinion situate between the two lines ot' loaded chain, to which pinion the power is applied. This part ot my invention is illustrate-d as applied to two sheaves in Figs. l and 2 of the drawings. The sheaves B and C have4 their main chain beds or grooves deepened at g, so as to form additional beds or grooves with IOO ' teeth to constitute chain-pulleys to receive small driving-chains h, passing thereover and over corresponding toothed grooves in the chain-pinion t, carried in the upper part of the lower-sheave framings, as shown. The driving of the pinion may be effected'in any convenient manner. In Fig..2 there is shown for this purpose a ratchet-wheel, j, attached to the axis of the pinion i, the lever h and pawl 7c being actuated like a ratchetvbrace to rotate the pinion fi, and through it and the chains h the sheaves of the pulley. If desirable, however, this chain-gear may be situate in a like manner in the bed ofthe single sheave above and then be actuated, as described, or it may be applied for driving the top sheaves of an ordinary Weston block.

Fig` .represents in elevation, and Fig. 6 in vertical section, a Weston block provided with the said improvement. The parts which correspond with those shown in Fig. 2 are markedwith the same letters of reference, and as the arrangement of my improvements in thisv respect is essentially similar to the arrangement ot'v the improvements as shown in the said Fig. 2, these Figs. 5 and 6 call for no further description. I have. here shown a sprocket-wheel, l,v as the means for giving motion to the pinion t', which in this arrangement is of course situated beneath the sheaves B G. It is evident, therefore, that the same gear is applicable, whether the differential sheaves be situate above, as in a Weston block, or

Y below, as in the arrange-ment hereinbefore first described, or whether one or more ofthe differential sheaves or the single sheave be driven.

The chains h will have a strain upon them in a proportion varying with the load but this strain will of course be of much smaller amount than that on the mainchain. I prefer for safetys sake to make the said chains h weaker in proportion than the main chain, so that these chains will break before the main chain, and thus prevent injury should the apparatus be unduly strained. This chain-gear may be combined with the lowering-gear described in the specification filed by myself and the said Edmund Howl, in pursuance of the before-mentioned Letters Patent dated the 17th September, 1881, No. 4,012, by arranging the block as a non-self-sustained block and introducing the detent and ratchet-wheel in the manner described in the said specification. This lowering-gear is shown at w in Figs. 1, 2,y and 5,6, and as its application differs in no respect from its application as described in the said prior specification it calls for no further description.

My invention is also applicable to cranes, f

overhead travelers, hoists, and other like apparatus to which it is or may be applicable.

Having now described and particularly ascertained the nature of my said invention and the manner in which the same is or may be used or carried into effect, I would observe, in conclusion, that what I consider to be novel and original, and therefore claim, is?- 1. A pulley-block having the single sheave at the top, and the differential sheaves below, with a chain passing over said sin gle sheave and partly around said differential sheaves, and guides for crossing said chain into a loop below the latter, all substantially as described.

2. The combination of the upper sheave and chain and the lower differential sheaves with the crossed-chain guides ff below the latter, substantially .as set forth.

3.' The combination of sheaves having two. sets of grooves, one within the other, with two sets of chains and an actuating-shaft having a driving pinion or pinions for the inner chain, substantially as specified.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

THOMAS HENRY WARD.

Witnesses:

HENRY BUCHLEY,

Merchant, Birmingham. J. FRANCIS BRAME,

Vice-Consul, U. S. A., Birrm'hgham.

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