US2548846A

US2548846A - Chain hoist

Info

Publication number: US2548846A
Application number: US783486A
Authority: US
Inventors: Erford E Robins; Humphrey F Parker
Original assignee: Columbus McKinnon Chain Corp
Current assignee: Columbus McKinnon Chain Corp
Priority date: 1947-11-01
Filing date: 1947-11-01
Publication date: 1951-04-10
Anticipated expiration: 1968-04-10

Description

April 10, 1951 E. E. ROBINS ET AL CHAIN HOIST Filed Nov. 1, 1947 2 Sheets-Sheet 1 ATTORNEYS April 1951 E. E. ROBINS ET AL 2,548,846

CHAIN HOIST.

Filed Nov. 1', 1947 2 Sheets-Sheet 2 LOAD INVENTOR SIDE frlard f. flab/n: 5 Hump/m7 1. Par/fer ATTORNEYJ Patented Apr. 10, 1951 CHAIN HOIST Erford E. Robins, North Tonawanda,and Humphrey F. Parker, Bulfalo, N. Y., assignors to Columbus McKinnon. Chain Corporation, Tona- Wanda, N. Y.

Application November 1, 1947, Serial No. 783,486

7 Claims. (01. 254-167) This invention relates to chain hoists, such as industrial hoists which carry their loads through welded link type chains which. reeve over load lift wheels carried by gear driven shafts. In this type hoist the load lift shaft is geared either to an electric motor or to a shaft which is keyed to a sprocket driven by a manually pulled endless chain. More specifically the invention relates to improvements in such hoists whereby it becomes practicable to design such hoists to embody minimum gear reduction ratios between the driving shaft and the load lift shaft by reducing the diameter limitations on the load lift wheels when employing chains of any given size of link.

Prior load lift wheels for use in connection with welded link style load chains have been successfully designed to operate with as low as five chain link receiving pockets formed into the peripheries thereof, but it has been found to be extremely difiicult and expensive prior to the present invention to forge such lift wheels with as low as three pockets therein, because of the great dimensional accuracywhich is required in a wheel forging having link pockets of previous style. This is because the relative fit of the load chain links and the wheel pockets becomes extremely critical in small size lift wheels, and severe secondary forces are developed in training of the load chain over a small lift wheel having conventionally shaped link pockets therein, resulting in rapid wearing of the chain and chain uide and wheel parts. Also, prior lift wheel pocket designs have proved to be inadequate when used in small size lift wheels to accommo- A date service-distorted chain, such as invariably results from wearing and/or stretching of the load chain under service conditions.

It is an object of the present invention to provide an improved design for chain hoist lift wheels, whereby such wheels may be constructed to lesser diameters when handling load chains having links of the same size and type, while permitting the load chain to train freely over the load wheel.

Another object of the invention is to provide an improved load chain link pocket configuration in chain hoist load lift wheels and the like, whereby to provide for improved floating of the load chain into load lifting geared relation with the hoist frame chain guide element and the load lift wheel, especially in connection with relatively small diameter lift wheels.

Another object of the invention is to provide an improved design for chain link pockets in chain hoist load lift wheels, whereby the lift wheels are adapted to be manufactured by simplified and less expensive processes compared to the manufacture of corresponding lift .wheels of the prior art. Still another object of the invention is to provide an improved design especially for small di ameter load lift wheels of the type referred to hereinafter, whereby such whels will tolerate somewhat oversize chain linkeand/or misshapen chain links without relative grinding and undue wearing of the wheel and chain link parts.

Other objects and advantages of the inventionwill appear from the specification hereinafter. I

In the drawing: M Fig. 1 is a fragmentary sectional view through a chain hoist mechanism embodying a load lift wheel of the present invention; 7

, Fig. 2 is a perspective of the load lift shaft and wheel unit thereof; I

Fig. 3 is a side elevation of the load lift shaft and wheel unit;

Fig. 4 is a sectional view takenv along line IV-IV of Fig. 3, on an enlarged scale, showing the hoist load lift chaintrained thereon;

Fig. 5 is a side elevational view of the load lift wheel, taken as along line V-V of Fig. 4;

Fig. 6 is a side elevational View of the load lift wheel. taken as along line VI-VI of Fig. 4; and Fig. '7 is a fragmentary sectional view .of the load lift wheel and chain guide portions of the,

hoist mechanisms, taken along line VII-NH of Fig. 1.

The invention relates particularly to hoists which employ 'chainof the type comprising interlooped links formed by bending and welding wire stock into oval link form, such as. is. illustrated in Figs. 4 and '7. i

The invention is illustrated in Fig. 1 in connection with a chain hoist comprising generally a casing l 0 which rotatably mounts a hand chain wheel l2. The hand wheel shaft I4 is supported in the casing 10 by means of bearings l6 and is geared at its inner end through-means of gears l1 and I8 to the hoist load lift shaft 20. The shaft 20 carries the load lift wheel-22, over which trains the load lift chain as is indicated at 25 .(Figs. 4 and 7). The hoist casing will of course be fitted with a hook whereby it may be suspended at any elevation; and it will be .understood that the load lift chain 25 will carry at its lower end a suitable hook device for attachment of the load to be lifted, Thus, upon-rotation of the wheel l2, as by pulling upon an endless hand chain 26. which is trained over the wheel l2 in mesh with the peripheral pockets thereof, the load lift wheel will be driven so as to elevate the load at a reduced speed compared to the movement of the hand chain, thereby acquiring great mechanical advantage and permitting a heavy load to be lifted in response to relatively light pulling upon the hand chain.

Thus, the hoist mechanism which has been described hereinabove is of the general type that is disclosed for example in U. S. Patent No.

2,243,361, and as is illustrated therein, a chain guide member in the form of a grooved metal piece is preferably mounted upon the interior of the hoist casing l0, as is indicated at 28 in Figs. 1 and '7. I

The chain guide member 28, isdesigned to receive the edgewise disposed links 30 of the load chain (Figs. 4 and 7) in the grooved portion of the chain guide, while the alternate flatwise disposed links 32 of the load chain bear against the edge portions 34--34 (Fig. 1) of the chain guide member and are biased thereby into flatwise seated relation against the land portions 35 of thelift wheel 22, to be carried around the axis of the shaft 20' in sliding relation against the chain guide surfaces 34-34. V

It is a particular feature of the present invention that the land portions 35 of the load lift wheel 22 are generally flat surfaces in planes offset from but extending'parallel to the axis of rotation of the wheel. However, the land surfaces 35 are interrupted and cut away centrally at the opposite ends thereof as indicated at 38, to accommodate therein the edgewise-disposed links of the load chain which interconnect the flatwise-disposedlinks (Figs. 4 and 7). Also, i

the otherwise flat surface configurations of the land surfaces 35 are interrupted at the trailing end portions thereof, when considered with respect to the direction of rotation of the wheel 22 when lifting a load, by a raised abutment 40 at each side of the land formation. As shown more clearly in Figs. 2-3- -6, the abutments 40-40 at opposite sides of each land formation are inwardly faced as indicated'at 42 so as to complement the curved end form of the flatwise-disposed chain links 32 as they are received by the flat land formations 35 of the lift wheel and pressed thereagainst by the action of the chain guide 28'.

Thus, it will be appreciated that the abutment portions '40 of the lift wheel 22 will thereby engage against the trailing end portion of each of the flatwise-disposed load. chain links as they train successively over'the lift wheel 22 whenever the latter is driven through means of the gearing l|l8 to rotate so as to lift a load. The number of lands formed o'n'the lift wheel will of course depend upon the speed reduction ratio prescribed between the driver shaft and the load lift chain, taking into consideration the speed'reduction ratio of the gear train l l- |8. Therefore, it will be understood that although in the present drawing the load lift wheel 22 is illustrated to be divided into three flat link receiving land portions, the wheel may be formed with any other desired number of land portions as may be required.

Thus, it will be appreciated that in the case of the presentv invention the load lift wheel member of the hoist mechanism presents to the oncoming chain links of the load chain, as, the load is being lifted, a series of flat land surfaces which are bounded at their trailing endportions with raised abutments shaped to complement the trailend portions of the as they are iQI'GFSid by the pulling of the load and by the pressure of the chain guide element to lie in snug-fitting fiatwise relation against the land surfaces 35; while the raised abutments 40-40 prevent the links 32 from sliding in endwise direction from the land surfaces. Thus, the raised abutments 40-40 restrain the fiat links 32 only against sliding in endwise direction in response to the pull of the load, while the links are relatively free to move laterally relative to the land surfaces, wherefor they may float into properly aligned relation upon the wheel 22 under the guiding influence of the chain guide element 28 and of the pull of the load forces. Because the load lift wheel exerts no lateral guiding forces on the chain links except at the trailing end portion of each land surface, there is no forcible grinding of the load chain into meshing connection with the wheel 22 and the chain guide 28, such as is the case in connection with prior art load wheel design including full length chain link pockets and the like.

It is another particular feature of the present invention that the load lift wheel design thereof facilitates manufacture of the wheel by simpler and less expensive manufacturing processes compared to the processes required in manufacture of load lift wheels of the prior chain link pocket type. For example, whereas such prior art type wheels must of necessity be manufactured either by complicated multi-die forging or machining processes to abnormally close tolerances, the wheel of the present invention may be forged by simpler forging operations or may be machined off by simple milling operations to producethe flat land surfaces 35 which are bounded at only one end and therefore involve no lateral tolerance measurements.

What is claimed is:

1. In a chain hoist, in combination, a load lift wheel and a chain guide device mounted upon said hoist in relatively spaced relation and so arranged as to cooperate to guide a load hoisting chain to train between the load lift wheel and the guide device, said load lift wheel comprising a member having a series of generally flat land portions extending peripherally of the wheel, each of said land portions being adapted to receive in flatwise-disposed relation thereagainst successive alternately flatwise disposed links of the load chain as the latter trains around the wheel, said land portions being centrally grooved at opposite ends thereof to accommodate the alternate edgewise disposed load chain links which interconnect the flatwise disposed links, said land surfaces terminating in upstanding abutment portions at the trailing end portions of said land surfaces in view of the direction of wheel rotation when lifting a load, said abutment portions being shaped to complement and bear against 'the trailing end portions .of the flatwise disposed chain links.

2. In a chain hoist, a load lift wheel rotatably mounted upon said hoist to receive a welded link type hoist load chain to reeve around the load lift wheel, said load lift wheel having a series of generally flat land portions extending peripherally thereof, each of said land portions being adapted to receive in flatwise disposed relation thereagainst successive alternately flatwise-disposed links of the load chain as the latter trains around the wheel, said land portions being centrally grooved at opposite ends thereof to accommodate the alternate edgewise disposed load chain links which interconnect the flatwise disposed links, said land surfaces terminating in upstanding abutment portions at the trailing end portions of said land surfaces in View of the direction of wheel rotation when lifting a load, said abutment portions being shaped to complement and bear against the trailing end portions of the fiatwise disposed chain links.

3. In a chain hoist, a load lift wheel mounted upon said hoist to receive a welded link type hoist load chain to reeve around the load lift wheel, said load lift wheel having a series of fiat'land. portions extending peripherally thereof, each of said land portions being adapted to receive in fiatwise disposed relation thereagainst successive alternately fiatwise disposed links of the load chain as the latter trains around the wheel, said land portions being centrally grooved at opposite ends thereof to accommodate the alternate edgewise disposed load chain links which interconnect the fiatwise disposed links, said land surfaces terminating in upstanding abutment portions at the trailing end portions of said land surfaces in View ofthe direction of wheel rotation when lifting a load, said abutment surfaces being frontally shaped to bear against the trailing end portions of the fiatwise disposed links.

4. In a chain hoist, in combination, a load lift wheel and a chain guide device mounted upon said hoist in relatively spaced relation and so arranged as to cooperate to guide a load hoisting chain to train between the load lift wheel and the guide device, said load lift wheel comprising a member having a series of generally fiat land portions extending peripherally of the wheel, each of said land portions being adapted to receive in fiatwise-disposed relation thereagainst successive alternately fiatwise disposed links of the load chain as the latter trains around the wheel, said land portions being centrally grooved at opposite ends thereof to accommodate the alternate edgewise disposed load chain links which interconnect the fiatwise disposed links, said land surfaces terminating in upstanding abutment portions at the trailing end portions of said land surfaces in view of the direction of wheel rotation when litfing a load, said abutment portions being shaped to complement and bear against the trailing end portions of the fiatwise disposed chain links, said guide device comprising a member centrally grooved to straddle the edgewise disposed chain links and having opposite side portions extending to bear against the flatwise disposed links for biasing the latter against said wheel land portions.

5. In a chain hoist, a load lift wheel rotatably mounted upon said hoist to receive a welded link type hoist load chain to reeve around the load lift wheel, said load lift wheel having only three generally flat land portions comprising the complete peripheral extension thereof, each of said land portions being adapted to receive in fiatwise disposed relation thereagainst successive alternately fiatwise-disposed links of the load chain as the latter trains around the wheel, said land portions being centrally grooved at opposite ends thereof to accommodate the alternate edgewise disposed load chain links which interconnect the fiatwise disposed links, said land surfaces terminating in upstanding abutment portions at'the trailing end portions of said land surfaces in'view of the direction of wheel rotation when lifting a load, said abutment portions being shaped to complement and bear against the trailing edge portions of the fiatwise disposed chain links.

6. In a chain hoist, a load lift wheel mounted upon said hoist to receive a welded link type hoist load chain to reeve around the load lift wheel, said load lift wheel having a series of less than five generally flat land portions comprising the complete peripheral extent thereof, each of said land portions being adapted to receive in fiatwise disposed relation thereagainst successive alternately fiatwise disposed links of the load chain as the latter trains around the Wheel, said land portions being centrally grooved at opposite ends thereof to accommodate the alternate edgewise disposed load chain links which interconnect the fiatwise disposed links, said land surfaces terminating in upstanding abutment portions at the trailing end portions of said land surfaces in view of the direction of wheel rotation when lifting a load, said abutment portions being shaped to bear against the trailing end portions of the fiatwise disposed chain links.

7. In a chain hoist, a load lift wheel mounted upon said hoist to receive a welded link type hoist load chain to reeve around the load lift wheel, said load lift wheel having a series of flat land portions extending peripherally thereof, each of said land portions being adapted to receive in fiatwise disposed relation thereagainst successive alternately fiatwise disposed links of the load chain as the latter trains around the wheel, said land portions being centrally grooved to accommodate the edgewise disposed links which interconnect consecutive fiatwise disposed links, said land surfaces terminating in upstanding abutment portions at the trailing end portions of said land surfaces in view of the direction of wheel rotation when lifting a load to maintain the fiatwise disposed links thereon against sliding therefrom in endwise direction.

ERFORD E. ROBINS. HUMPHREY F. PARKER.

REFERENCES oI rED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,243,361 Stahl May 27, 1941 FOREIGN PATENTS Number Country Date 86,452 Sweden June 3, 1936