US1765347A - Crane hoist - Google Patents

Description

June 11,1930, J. A. SHEPARD 1,765,347

' 01mm: HOIST Filed 'July 7,v 192::

I N V EN TOR. Jams-.5 r1 5/15/ 420 Patented June 17, 1930 UNITED-STATES PAT mean? JAMES A. SHEPARD, OF MONTOUR FALLS, NEW YORK, ASSIGNOR TO SHEPARD-NILES I CRANE & HOIST CORPORATION, OF MONTOUR FALLS, NEW YORK, A CORPORATION 4 OF NEW YORK Application filed July 7,

and form loops, each of which passes about a corresponding pulley, the two pulleys be mg each journalled in the same load supporting, pulley block frame. In such a'hoist it is the regular practice to fasten the ends of the two cable elements to the winding drumat points adjacent the opposite ends of. the drum, and to cause the portion of each element wound about the drum when a load is raised, to assume the form of a helix, the convolutions of each helix approaching those of the other as the load raising operation proceeds.

v The object of the present invention is to provide a hoist of the type described with a pulley block so constructed and disposed as to permit the convolutions or coils of the two cable elements wound about the drum to-come closer to-one another when the pulley block is in its uppermost position, than has heretofore been practically possible in such a hoist. A practically important result of thus reducing the minimum distance between the adj acent coils of the two cable elements, is a reduction in the winding drum length required to wind up given lengths of cable elements, or stated differently, an increase in the cable winding capacity of a winding drum of given dimensions. 7

For reasons hereinafter explained, the minimum distance between the adjacent convolutions of the two cable elements wound about the winding drum depends upon and is approximately equal to the distance between the cable receiving grooves of the pulley wheels at the sides ofthe latter adjacent the winding drum when the pulley block is in its uppermost position. In accordance with the presentinvention, I reduce the last mentioned distance by mounting the two pulley wheels of the load supporting block to turn aboutaxes which are notcoincident as has heretofore been customary, but which are obliqueto. one anotherso that the sides of a the. two pulley wheels which are adj acentthe winding drum when the block is in its upper- CRANE HOIST 1928. Serial No. 290,956.

remote from the winding drum may comprise an equalizing pulley of amply large dianieter. The use of an equalizing pulley anchorage is common, but heretofore in many cases it'has not been p ractically possible to use an equalizing pulley of as large diameter as is desirable.

The various features of novelty which characterize my invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, however, and the advantages possessed by it, reference should be had to the accompanying drawings and descriptive matter in which I have illustrated and described preferred embodiments of the invention.

Of the drawings: I Fig. 1 is a plan view of a hoist; Fig. 2 is an end elevation ofthe hoist shown in Fig. 1 with parts broken away; and

Fig. 3 is a diagrammatic perspective view showing the hoisting drum, pulley, cable, and cable equalizer arrangement. I In the'drawings I have illustrated the use of the present invention in conventionally illustrated hoist A of well known type. f The hoist A shown comprises framework adapted to be suspended from a track rail (not shown) through trolleywheels B, and in which is mounteda hoist winding drum C, and its driving motor A, and braking mechanism A respectively. Associated with the winding drum are two cable elements D and d, each of which has one end attached to the drum C,the pointsof connection, C, for thetwo elements being adjacent the opposite ends ofthe'drums as shown in Fig. 3. The

opposite end of each cable element is connected to the hoist framework at a distance from the drum C depending generally upon the size of the pulley wheels F and f. The

latter are mounted in the load supporting pulley block frame E, and are supported by loop portions of the cable elements D and (Z, respectively, depending from thehoist framework and winding drum.

'In practice the cable elements D and d are ordinarily sections of wire rope, but of course I may use equivalents for wire rope, such as chains and hempen ropes. l/Vhile the cable elements D and d may be entirely, separate from one another and may have their ends remote from the winding drum C separately about or unwound from the drum C, and the lengths of the cable element loops support ing the pulley wheels F and f are correspondingly shortened and lengthened. Ordinarily the drum is formed with spiral grooves at its periphery to insure the proper helical disposition of the cable element convolutions or turns encircling the drum, and in any event 7 the length of the unwound central portion C ofthe drum. decreases and increases as the load 1S raised and lowered. v v In accordance, with the present lnvention,

however, the pulley wheels F and f are mounted in the frame E toturn about axes F" and f, respectively, which are so inclined to one another that the sides of the pulv ley' wheels adj acent the winding drum C are closer together than are the opposite sides of the pulley wheels as is clearly shown in V Fig. 1'.

In consequence of this oblique pulley axis arrangement, it is possible to'hav'e the adjacent convolutions of the cable elements D and (Z wound about the winding drum G come closer to oneanother, when the pulley block is in its most elevatedposition, than has been heretofore possible. lhe decrease in winding drum length required for a given cable winding capacity thus made possible bythe use of the presentinvention, may be'eX- plained as follows. To minimize cable and pulley block stresses the cableelement por-' tions between the pulley wheels F and 7", and

the winding drum C should each extend in an approximately tangential direction from V the winding drumand from the corresponding pulley wheel. 'When the pulley block reaches itsmost elevated position, shown in Figs. 1 and 2, the lengths of the portions of two cable elements D and d between the pulleys F and f and the drum O become very short, and said portions must then be approximately parallel with one another to approXimate the desired tangential relation with the winding drum and pulley wheels. This requiresthat when the pulley block is in its most elevated position, the length of the unwound central portion C of the drum C should be approximately equal to the distance between the cable receiving grooves in the pulley wheels F and f at the sides of the latter from which the cable elements pass to the winding drum. A decrease in the last mentioned distance thus increases the eifective cable winding capacity. of a winding 7 drum of given diameter and length.

When the pulley block is lowered as shown in Fig. 3, from its uppermost position, the distance between the adjacent coils of the portions of the cable elements D and d, respectively, wound about the winding drum C increases, but since the length of the cable element sections extending between the wind ing drum and the pulleys is correspondingly increased, the desired approximately tangential relation is not impaired.

7 To minimize cable and pulley block stresses,

the cable elements between the pulley wheels f F and f, and the pulley wheel H should pass tangentially or approximately so, from each of the pulley wheels, and, in addition. the radius of curvature of the portion of the cable in Contact with the pulley H should not be unduly small. Heretofore, with the pulley wheels of the load supporting pulley block arallel to one another, desi ners. in an endcavor to reduce the length of the unused central section of thewinding drum, have commonly sought to bring the two pulley wheels of the pulley as close together as was practically possible. In consequence, there has been a tendency to make the diameter of the equalizing pulley seem all as to bend the cable section looped about it more sharply than'is' desirable. /Vith the present invention, there no occasion for such tendency, since the sides of the oppositely inclined pulley wheels F and f remote from the winding drum, may readily be separated as widely as is required to accommodate, or correspond to a diameter of the equalizing pulley H as large as may be practically desirable. 1

While in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known tome, it will be apparent to those skilled in the art that changes maybe made in the form of the apparatus disclosed with out departing from the spirit of my invention as set forth in the appended claims and that in some cases certain features of my inven- Ill) tion may be used to advantage without a corresponding use of other features.

Having now described my invention what I claim as new and desire to secure by Letr! ters Patent; is: i

1. In a hoist comprising a winding drum and two cable elements each having one end connected to an anchorage and having its pposite end connected to said winding drum at a point displaced longitudinally of the drum from the point at which the other element is connected to the drum, and in combination therewith a pulley block comprising a frame and two pulley wheels, one of which is supported in a looped portion of one of said elements extending between its anchored end and the winding drum, and the other of which is supported by a corresponding looped portion of the other cable element, said pulley wheels being journalled in said frame to turn 7 about axes so inclined to one another that the sides of said pulley wheels from which the respective cable elements pass to said winding drum are closer together than are the sides of said wheels from which said elements pass to said anchorage.

2. In a hoist comprising a frame winding drum journalled therein, an equalizing pulley wheel also journalled in said frame and a cable having its ends connected to said winding drum each at a point displaced longitudinally of the drum from the point at which the otherelement is connected to the drum, and having an intermediateoportion looped about said equalizing pulley wheel,and in combination therewith a pulley block comprising a frame and two pulley wheels one of which is supported in one and the other of which is supported in the second of the two looped o portions of said cable extending between the opposite sides of said equalizing pulley wheel and said winding drum, said two pulley wheels being journalled in said frame to turn about axes so inclined to one another that their sides from which cable portions pass directly to said windingdrum are closer together than are their sides from which cable portions pass directly to the opposite sides of said equalizing pulley wheel.

Signed at New York city, in the county of New York and State of New York this 6th day of July, A. D. 1928.

JAMES A. SHEPARD.

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