US2781671A - Chain hoist - Google Patents

Description

Feb. 19, 1957 w. H. DEVONSHIRE CHAIN HOIST Original Filed April 23, 1948 ATTORNEYS United States Patent We CHAIN HOIST William H. Devonshire, Williamsville, N. Y.,' assignor to Columbus McKinnon Chain Corporation, Tonawanda,

Original application April 23, 1948, Serial No. 22,916. Divided and this application August 31, 1953, Serial No. 381,061

2 Claims. c1. 74-243 This invention relates to chain hoist blocks, and more particularly to improvements in idler sheaves and en: closed block mechanisms such as carry the load engaging hook in multiple reeved chain hoists and the like. This application is a division of copending application Ser. No. 22,916, filed April 23, 1948, now abandoned.

In link chain hoists it is customary to employ pocketed sheaves sometimes known as pocket wheels about which the hoisting chain trains; for example, as is illustrated at 35 in Fig. 4 of U. S. Patent 2,373,048. It is also customary in the chain hoist art to enclose the sheave elements between multi-part casings or body members which are bolted together to complete final assembly of the block mechanism. In any case the overall design of the sheave block is unduly large and cumbersome, and the multiplicity of and the nature of the required parts completing the final assembly contribute to expensiveness in manufacture and undesirable overall size.

Therefore, it is an object of the present invention to provide a block and sheave mechanism for use in connection with a link chain type hoist, which may be designed to reduced overall dimensions and to be constructed of a reduced number of parts such as are relatively inexpensively manufactured.

Another object of the invention is to provide in a chain hoist mechanism an improved idler sheave block unit which is of improved structural simplicity and ruggedness and of reduced overall dimensions.

Another object of the invention is to provide in a link chain type hoist mechanism a novel sheave wheel.

Another object of the invention is to provide a novel form of sheave block in a chain hoist or the like.

Another object of the invention is to provide in a chain hoist system an improved sheave and bearing arrangement.

Other objects and advantages of the invention will appear from the specification hereinafter.

In the drawing:

Fig. 1 is a vertical sectional view through a chain hoist hook block and sheave device of the invention, with a load hook suspended therefrom;

Fig. 2 is a perspective, on' an enlarged scale, of one of the sheaves of the mechanism of Fig. 1; and

Fig. 3 is a section taken along line III-III of Fig. 2.

The invention is illustrated in Fig. 1 to comprise a multiple reeved chain hoist lower hook block body which may be manufactured in the form of a single casting having a single bore extending laterally therethrough as indicated at 12. The casting 10 is provided with enlarged chambers 14-14 communicating with apertures 16-16 through the top portion of the casting to accommodate the load chain 18-18 extending from the hoisting mechanism thereabove (not shown). Thus, as illustrated in Fig. 1, the sheave block shown therein by Way of one example of the invention is provided to accommodate a quadruple reeved hoist chain arrangement; but it will be understood that the invention is applicable 2,781,671 Patented Feb. 19, 1957 with equal facility to any other multiple reeve hoist chain arrangements.

The chain idler sheave mechanism is therefore illustrated in the drawing to comprise a pair of sheaves each of which is designated generally at 20in the drawing. Fig. 2 illustrates one of the sheaves 20 disassembled from the other mechanism; and as shown more clearly in Fig. 2, the sheave comprises a generally polygonal shaped body of metal formed with trunnion shafts 22-22 extending in diametrically opposed relation from opposite sides thereof. The body portion of the wheel 20 is flatsided as indicated at 24 to receive in flatwise disposed relation thereon alternately successive links of the chain 18 as indicated at 2626, (Fig. 3). The ad.- jacent flat surfaces 24 are disposed at right angles to each other, and the corners formed at the intersections thereof are, channeled as indicated at 28 centrally thereof to accommodate the alternately successive edgewise disposed links of the chain 18 (as indicated at 30). Thus, the chain 18 trains around the sheave 20 in such manner that alternately successive links of the chain lie flatwise against the fiat surfaces 24 while the edgewise disposed links of the chain are cradled within the channels 28 of the sheave. Inasmuch as the chain 18 is merely running idle, around the sheaves 20-20 the 90 angular relation of the adjacent fiat portions 24 of the sheaves assures adequate gearing of the chain to the sheave even though the sheave surfaces 24 are perfectly flat.

Thus, by designing the sheave to include a minimum number of link engaging flat surfaces, which in the example shown amount to four of such surfaces, and by eliminating the previously customary pocketing external ridge formations which are customarily provided to extend away from the edges of the chain link receiving surfaces the overall diametral dimensions of the sheaves '20 are minimized. Furthermore, as indicated at 31, the

corner portions of the sheave are turncated so as to further reduce the overall diameter of the sheave. This enables the sheave-s 20 to be mounted within the block casting 10 in improved manner because by reason of the reduced diametral dimensions of the sheaves they are adapted to be inserted laterally into the bored portion 12 of the block 10 from the opposite sides thereof into the operative positions shown in Fig. 1. Anti-friction bearing units 32 are first fitted upon each of the stub shaft portions 22 of the sheaves and then the sheavebearing units are in turn slip-fitted into the bored portion 12 of the block casting from the opposite sides thereof. Preferably, a spacer 33 is fitted in between the outer races of the bearings 32-32. Retainer rings 34 are then set into grooved portions of the block casting so as to hold the hearings in centered positions, and preferably cover plates 35 are then press-fitted into the outer ends of the block bore so as to complete enclosure of the mechanism. The load chain 18 may then be reeved through the block into geared arrangement around the sheaves 20-20, and the block is ready for service. As explained hereinabovve, the block casting may include a yoke portion 36 which is bored to receive the upper end of a load engaging hook 38; a lock nut 39 being employed to maintain the hook in the yoke.

Thus, it will be appreciated that by reason of the use of flatsided load chain link engaging surfaces as indicated at 24 in lieu of pocket shaped surfaces for receiving the load chain links, the outside diametral dimensions of the sheaves 20 are reduced so that it becomes practicable to simply bore the single block casting to provide a single lateral bore therethrough into which may be slip-fitted the sheaves 20-20 when carrying with them the bearing units 32 which are of outside diameters only slightly larger than the greatest diametral dimensions of the sheave and slightly smaller than the diameterpf the block bore so .as to be adapted to .be .slipfittedth'r'ein. "Consequently, the block may be made in the form of a single castinghaving compactly contained therein the sheave .and bearing devices, all in the form of a rugged mechanical unit of improved compact'hess' requiring 'no t'i bolts or the like to maintain separ ate body parts together and in proper alignment, afsin the case or the prior artf lt must-be appreciated that the present invention solves' 'alparti'cularly difficult problem in connection with the mounting of block sheaves of the type carrying very great loads in prop'or't'ion'to the sheavesiz'ef' In such case, for example, it is impracticable to employ the" conventional pulley type sheave'wheel such as' is inserted 'edge'wisethrough a slotted portion o'f'a pulley block and'the'n engaged within the block by sliding the pulley shgaffendvvise into' theblock and through the pulley hubl Such pulley-block"arrangements are satisfactory for relativei y light duty purposes, whereas the present invention deal son'ly' With-heavy dutysheavebIock mechani's'rnsand provides novel features referred'to hereinabove in combination with optimum strength-tomateriallratioin the she'avebearing unit. This is-because thesheaveand trunnion shaft portions ;20 22 may be readily produced in the form of a single forging of high strength metal, whereby the shaft and sheave body portions' reinforce each other and provide a rotating sheave unit yvhich' is of optimum compactness and ruggedness. This rotatable unit is carried within amply sized bearings which are disposed within that portion of the block which is'not occupied by the sheaves and chain; and therefore the elements of the mechanism of the invention are arranged to provide a novel combination of .parts producing important features and advantages .in

the art.

"Whatis claimed is:

1. An idler sheave for use with a link chain comprising a body member of generally square prism form having stub shaft portions formed integral therewith and extending from the opposite ends thereof for providing the axis of rotation thereof, said-body member being fiatsided to receive in fiatwise disposed relation thereon alternately successive linksof a "chain, the corners of said body member being'truncated in planes parallel to said axis and being centrally grooved in a direction normal to said axis to receive therein the intermediate edgeiiiisc disposedlinks of the chain.

2. An idler sh'e ave for use with a link chain, said sheave comprising a body member of generally square prism form having flat side surfaces for receiving in ilatwise disposed relation thereonsu'ccessive flatwise disposed links of a chain, the adjacent side surfaces being disposed at substantially right angles to each other, stub shaft portions formedfinteg'rally With said body member and extending from the opposite ends thereof for providing the aXis Of lrotationthereof, the 'eorn ersof' s'aid body member'being truncated in planes parallel to said axis and being channeled centrally thereof to accommodate the successive edgewise disposed 'links of the chain.

References Cited in the file of this patent UNITED STATES PATENTS Dillon Nov. 21, 191.6

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