US2738954A - Hoist - Google Patents

Description

A March 20, 1956 A, E, DU Bols 2,738,954

HOIST Filed Dec. 31, 1953 2 Sheets-Sheet 1 IN V EN TOR.

iff/YMEJZEUE' March 20, 1956 A. E. Du Bols HOIST 2 Sheets-Sheet 2 Filed Dec. 51, 1953 United States Patent O HolsT Arthur E. Du Bois, Fort Lauderdale, Fla., assignor to Aluminum Products, Inc., Fort Lauderdale, Fla., a corporation of Florida Application December 31, 1953, Serial No. 401,573

4 Claims. (Ci. 254--167) This invention relates to hoists or mechanical Winches and more particularly to a hoist for controlled winding and unwinding cable and the like under load pressure.

An object of this invention is to provide a hoist with holding and loading pawls with cam means co-acting therewith in conjunction with reversibly biasing tension means on the loading pawl. to controllably wind and unwind cable under-load pressure.

Another object of this invention is to provide a drumtype hoist of the class described with releasable cable securing means for refastening new cable or broken cable.

Another object of this invention is to provide a twostep spring controlled cam for actuating the holding pawl of a hoist of the class described in and out of engagement with a ratchet wheel.

A further object of this invention is to provide a hoist of the class described which will be simple and economical in construction and repair, and eicient and durable in use.

v The foregoing and other objects and advantages will be more fully understood from reading the following specication, in conjunction with the drawings forming a part thereof, wherein:

Fig. l is a side elevational view of a hoist of this invention as positioned for pulling a load over an overhead pulley;

Fig. 2 is a side elevational view of the hoist of Fig. l as viewed from the other side thereof;

Fig. 3 is a fragmentary cross-sectional view taken along line 3-3 of Fig. l, parts shown in elevation for clarity:

Fig. 4 is a cross-sectional view taken along line 4 4 of Fig 3, parts shown in elevation for clarity;

Fig. 5 is a perspective view of the loading pawling with reverse biasing ears and spring;

Fig. 6 is a view of the device shown in Fig, l with the side lof the frame removed to show the relationship of the interior working parts;

Fig. 7 is a face elevational view of Fig. l, with operating handle removed;

Fig. 8 is a perspective View of the holding pawl and operating cam assembly; and

Fig. 9 is a fragmentary and enlarged cross-sectional view of the drum taken along line 9 9 of Fig. 6, showing releasable cable clamping assembly, parts shown in elevation for clarity. i

Referring tothe drawings, wherein like members are given the same reference numeral, a substantially rectangular frame 1 has an anchoring hook or eye 2 swivelly mounted in one end along the longitudinal axis thereof. The other end of the frame is provided with a boss 3 spaced inwardly from the end member of the frame 1, and aligned apertures 4 and 5 in said boss V3 and end of the frame 1, respectively, alongkthe longitudinal axis of the frame and adapted to receive and guide a cable 6.

The frame 1 supports a shaft 10 positioned transversely therethrough and press-htted into bushed apertures 11 provided in the sides of said frame 1. Rotatably mounted v 2,738,954 n Patented Mar. 20, 191.56

on the shaft 10 is a ratchet-wheel drum comprising a cylindrical body 12, an annular ilange 14 onone end and a ratchet wheel 15 ron the other end. ,A U-shaped member 16, having approximately the same transverse dimension as the frame 1, has the legs thereof rotatably mounted on the shaft 10, one leg intermediate the flange 14 and side of the frame 1,' and the other leg externally of the frame 1 on the side adjacent the ratchet wheel`15. Operably fastened to this latter leg of the U-shaped member 16 is an operating lever or arm 17, in a conventional manner such as nut and bolt assembly 18 and aperture 19 receiving the shaft 10 and a feed pawl shaft Ztl described hereinafter.

A transverse feed pawl shaft 20 is rotatably supported by the U-shaped member 16. A loading or feeding pawl 21 is rotatably mounted on the shaft 20 in alignment with the ratchet wheel 15 and held in such alignment by guides 22 and 23, on each side of said pawl 21, fastened to the shaft in any conventional manner, such as set screw 24. The guide 23 has an apertured ear 25 adapted to receive one end of an L-shaped toggle spring element 26 having the other end thereof pivotally mounted in an aperture 27 of the central section of the U-shaped member 16. The feeding pawl 21 is provided with a pair of ears 28 and 29, between which the spring element 26 passes. When the shaft 20 is in the position illustrated in Figs. 3, 4, and 5, the spring element 26 is past its center point and presses against ear 28 to urge the feed pawl 21 into engagement with the ratchet wheel 15; whereas, with the shaft 20 rotated back approximately a fourth revolution, the spring 26 is biased in the opposite direction and pressed against ear 29, raising the feed pawl 21 from engagement with the ratchet wheel 15 and to over-ride the wheel 15. To limit the rotation of feed pawl 21 when in over-ride position,V a stop projection 30 4ice is provided on the U-shaped member 16 to abut the spring i 26 in this direction of bias. To facilitatel rotation of the shaft 20, a knob 31 is fastened tothe shaft 20 externally of the U-shaped member 16. 'y

A shaft 40 is journaled in the side members of the frame 1, and pivotally supports a holding pawl 41 thereon whereby the holding pawl is aligned with the ratchet wheel 15 for engagement therewith and pivoted out of engagement therewith. Pivotally mounted to the frame 1 intermediate the frame 1 and holding pawl 41 is a cam element 42, having a projection 43 journaled for free rotation in an aperture 44 in the frame 1. The cam element 42 has an aperture or eye 45 in an end thereof adapted to receive a stud projection 46 onthe holding pawl 41. A compression spring 47,' illustrated as a U- shaped spring, has one end thereof fastened to the `cam 4Z and the other end thereof fastened to the stud projection 46 of the holding pawl, urging the holding .pawl 41 out of engagement with the ratchet wheel 15; but, another spring element 48 of greater strength than spring 47, illustrated as a tension spring, has one end thereof fastened to the cam element 42 and the other end fastened to the frame, in any conventional manner, such as a pin, to oppose the force of spring element 47 and urge the holding pawl 41 into engagement with the ratchet wheel l5 by the eye 4S abutting the stud 46 and pulling the pawl 41 toward the ratchet wheel 15 over the opposed force of the weaker spring 47. The holding pawl j 41 has a projection 49 extending beyond the frame 1y to permit manual disengagement of holding pawl 41 and ratchet wheel 15 by rotating the pawl over the action of the spring 48.

The loading pawl 21 has a lateral projection 51 thereon which abuts a lateral projection 52 on the cam 42, when the loading pawl 21 is in over-ride position, to overcome the action of the spring 4S and permit spring 47 to disengage the holding pawl 41 from the ratchet wheel 15 while cammingV the` loading pawl 21 into engagement with. the ratchet wheel, thus permitting a single ratchet-tooth reverse action of the drum at each step.

The drumcylinder 152 has ichord-wise aperture 55' extending therein and` communi atingwith the end of a longitudinally positioned'tapped aperture 56. T-he free end-ofI the cable 6 is received by the chord-.wise aperture 55l and clamped therein by a oatingmember 57' having a. concave end-58 tting around the cable 6 and forcing the cable againstthe end of tappedaperture 56 by the action of a plug 59 threadedly engaging the tapped section of aperture 56 andA forcing the free floating member 57 toward-` they end ofthe aperture 56 clamping the cable 6 therebetween.

In operation, with a cable 6 clamped in recess 55 by the sliding member 5 7 and knob 31 turned to position the loading pawl 21 in over-ride position, by pulling the holding pawlprojection 49 toward the drum 12 to release the-holding pawl 41 from the ratchet wheel 15, the cable 6 may be freely moved to a load. When the knob 31 is turned to load position as illustratedinFig. 1, by raising andl lowering the operating handle 17, the loading pawl 21 engages the ratchet wheel15 to wind-the cable 6 onto the drum 12, with the holding pawl 41 operating normally to prevent back rotation ofthe drum of engaging the ratchet wheel 15.

When it is desired to lower a load which has been raised, the loading pawl 21 is placed in over-ride position by turning the knob 31. Rotation of the operating lever 17 permits the loading pawl 21 to over-ride the ratchet wheel 15 until the projection 51- contacts the cam projection 52, overcoming the force spring 48 to permit spring 47 to force holding p awl- 41 from engagement with.the ratchet Wheel 15, which projection 52 cams the loading pawl 21 into engagement with the ratchet wheel 15. When the leverV 17 is reversed the holding pawl 41 engages the ratchet wheel 15 in the next tooth, thus loweringthe load one ratchet tooth distance. Repeated action lowers the load, a tooth ata time.

The invention has been described in detail, but it is clearly understood that it is not so` limited. Many changes and modifications `can be made therein without departing from the` spirit andscope thereof as defined in the appended claims.

Having thus described the invention, what is claimed as new and` desired to secure by grant of United States Letters Patent is:

l. A hoist comprising a frame, a drum having a ratchet wheel rotatable therewith, anoperating lever, a rotatably mounted loading pawl operatively connected with said-lever and in alignment withsaid ratchet wheel, a spring biasing said loading pawl, means selectively biasingsad spring to bias said loading pawl in or out of ratchet engagement, a. holding.. pawl pivetally connected to said frame and in alignment with said ratchet wheel, a cam pivotally mounted intermediate said pawls and positioned to contact and cam said loading pawl into ratchet engagement when said loading pawl is biased out of ratchet engagement, spring means connecting said cam and holding pawl and biasing said holding pawl out of ratchet engagement, and cam holding spring means biasing said cam to urge said holding pawl into ratchet engagement against the opposing bias of said other cam spring means.

2. A hoist as described in claim 1 wherein said cam is pivoted against the bias of said cam holding spring upon contact with-the loading pawl to position the holding pawl out of ratchet engagement and cam the loading pawl into ratchet engagement against the bias of the loading pawl biasing spring.

3. A hoist as described inclaim 1 in which the loading pawl has two projections thereon, a toggle spring intermediate said projections, and means selectively positioning said toggle spring to exert force upon either of; said projections to position the ratchet engaging end of said loading pawl in or out of ratchet engagement.

4. A'hoistcomprising a frame, a drum, a ratchet wheel, loading pawl, holding pawl, and operating lever, resilient means selectively positioning said loading pawl in and out off ratchet `wheel engagement, a pivotally mounted camintermediate said pawls, resilient means connecting said cam and holding `pawl normally urging said holding pawl out of ratchet engagement, cam resilient` means urging said camtin a direction opposedto and to overcome said other cam resilient means to position said holding pawl-in ratchet engagement, and said loading pawl, holding pawl, and'cam being so constructed with projections on saidcam andsaid loading pawl and arranged with said pawls and said cam projection in alignment with said ratchetand saidcam and loadingpawl projection aligned that operating the loading pawl when positioned out of ratchet. engagement abuts said cam and is cammed into ratchet engagement while pivoting thecam against the bias-of1saidcam resilientmeans to permit said cam and holding pawl'resilient means to `position said'holding pawl out of ratchet engagement.

References Cited in the tile of thispatent` UNITED STATES PATENTS 552,044 Crooker Dec. 24, 1895 2,100,674` Stahl NOV. 30, 1937 2,189,447` Martin Feb. 6, 1940 2,270,271 Cong Jan. 20, 1942 2,506,029 Maasdam May 2, 1950 2,584,099. Harkrader Jan. 29, 1952 2,633,328 Wallace Mar. 31, 1953

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