US2854852A - Operating lever assembly for winchtype hoist - Google Patents

Description

OPERATING LEVER ASSEMBLY FOR WINCH-TYPE HOIST K R A L c a w Filed Nov. 20, 1956 new 4 w o m g U w H. o a s w m G w m e m United States PatentO OPERATING LEVER ASSEMBLY FOR WIN CH- TYPE HOIST Walter C. Clark, Fort Lauderdale,

num Products, Inc., tion of Florida Fla., assignor to Alumi- Fort Lauderdale, Fla., a corpora- This invention relates generally to operating lever assemblies for winch-type hoists of the kind which utilize a rotatable winding drum with a ratchet wheel connected thereto, together with cooperating holding and loadlng pawls therefor; and it is concerned particularly with special means by which to guide the handle into an operative position such as will avoid fulcruming thereof by a holding sleeve wherein the handle is fitted.

A hoist of the kind described may be operated both for lifting or pulling a load and thereafter for lowermg or releasing the load, usually in response to gravity. In changing from a lifting to a lowering operation it is customary to reverse the bias of a spring which normally urges the loading pawl into ratchet engaging position, whereby to retract this pawl to a normally over-riding position relative to the ratchet wheel. When done, this pawl which is pivotally mounted on an operating lever is advanced by the latter idly toward the holding pawl which normally remains engaged with the ratchet wheel to sustain the load. The loading pawl near the conclusion of its movement engages the cam which then operates to disengage the holding pawl from the ratchet wheel while concurrently permitting the loading pawl itself to reengage a tooth of the wheel at a point which is adjacent the tooth just vacated by the holding pawl. The operating handle, When reversely moved, also retracts the loading pawl the necessary distance for the holding pawl to reengage the next adjacent tooth of the ratchet wheel, thereby permitting a controlled lowering of the load for a distance equal to the spacing between two ratchet teeth.

The operating handle herein disclosed is tubular and removably fitted into a sleeve carried fast on a lever that is pivoted to swing coaxially of the ratchet wheel; when stroked to raise or lower a heavyload the handle on its leading side is subjected to a compressive force and on its trailing side to a tension force at the point of its emergence from the sleeve, these opposing strains tending to produce a bend or break in the handle at that point. It is to prevent the occurrence of any such mishap by requiring the handle to occupy within its associated sleeve a predetermined position of maximum security that the present invention is primarily concerned.

A suggestive exemplification of my improved operating handle designed for use with a lever-operated hoist of the winch type, is illustrated in the accompanying drawings wherein:

Figure 1 is a front (or rear) elevation of the complete hoist except for the operating handle which is omitted from the view;

Figure 2 is a vertical sectional view through the frame, taken on line 22 of Figure 1, showing in elevation the principal operating parts of the hoist;

Figure 3 is a detail in front (or rear) elevation of the U-shaped member with its associated loading pawl and holding sleeve for the operating handle;

Figure 4 is a longitudinal section through the holding sleeve, taken on line 4-4 of Fig. 3, the handle end portion receivable in the sleeve being also shown in operative position therein.

Referring to the drawings, there is shown a substantially rectangular frame 10 which the usual anchoring hook or eye (not shown) may be swivelly mounted in one end wall along its axis. The lower end wall of the frame is also provided with a bushed opening 11 through which a cable 15 is guided in its movements during normal operation of the hoist.

The frame 10 supports a transverse shaft 16 journaled for rotation within bushed apertures (not shown) provided in the frame side walls. Carried fast on the shaft 16 is a ratchet-wheel drum comprising a cylindrical body 17, an annular flange 18 on one end thereof, and a ratchet wheel 19 on the other. As by a hand wheel 14 afiixed to one end of the shaft 16 the latter and the drum 17 may be turned to a desired rotative position whenever the hoist is free of a load. A lever in the form of a U-shaped member 20 having approximately the same transverse dimension as the frame 10 has its two legs rotatably mounted on the shaft 16, one leg being positioned intermediate the flange 18 and the proximate side of the frame and the other leg adjacent the opposite frame side, but externally thereof. A handle 21 is secured at one end within an elongated sleeve 22 carried fast on the external leg of the lever 20. Both of the legs of this member are apertured at 23 to receive the shaft '16. The handle 21 in combination with the lever 20 constitutes an operating lever assembly for the hoist and will be so referred to hereinafter at times.

A transverse pawl shaft 25 is also rotatably supported by the U-shaped member 20. A loading or feeding pawl 26 is rotatably mounted on this shaft in alignment with the ratchet wheel 19 and held in such alignment by hubs 27 and 28 which are extended outwardly on opposite sides of the pawl. A collar 29 fast on the shaft 25 carries an apertured ear 30 adapted to receive one end of an L-shaped toggle wire spring element 31 having its other end pivotally mounted in an aperture 32 of the connecting section of the U-shaped member 20. The loading pawl 26 is provided with a pair of cars 33 and 34 between which the spring element 31 extends. When the shaft 25 is in the position illustrated in Fig. 2, the spring element 31 lies past its center point to press against the car 33 and bias the feeding pawl 26 into engagement with the ratchet wheel 19; whereas, with the shaft 25 rotated back approximately a fourth revolution, the spring element 31 is biased in the opposite direction and pressed against the ear 34, thereby swinging the feeding pawl 26 away from engagement with the ratchet wheel 19 and into an overriding position relative thereto. To limit the rotation of the feeding pawl 26 when in its over-riding position, a stop lug 35 is provided on the U-shaped member 20 in position to engage the lug ear 34; and to facilitate manual rotation of the shaft 25 a radial knob 36 is fastened to its end at a point externally of the U-shaped member 20 (see Fig. l).

A shaft 37 journaled in the side members of the frame 10 pivotally supports thereon a holding pawl-38 having oppositely extended hubs whereby to fix the position of the pawl in alignment with the ratchet wheel 19 for engagement therewith. Pivotally mounted to the frame 10 at 42 is an elongated cam 39 mounting a spring 48 in resilient operative connection with the holding pawl 38 for governing the swinging movements thereof. The details of this cam-pawl assembly form no part of the present invention so further description thereof will be omitted.

The holding pawl 38 is provided near one end with a lateral bore extending inwardly from its side which faces the remote side of the frame 10 wherein is provided a similar bore (see Fig. l). A spring 51 coiled about the axis of the shaft 37 is extended between the holding pawl and the frame with opposite ends 52 and 53 of the spring disposed parallel for anchorage in thebores of the pawl and frame, respectively. This spring is biased to urge the acting end of the holding pawl into engagement with the teeth of the ratchet wheel andis amply strong to overcome the counter-tension normally exerted by the wire spring 46. The holding pawl is also extended away from its acting end outwardly and beyond its pivotal axis as at 5 to a point clear of the frame so as to be accessible for manipulation at such times as his desired to free the drum 17 for reverse rotation, as when the cable wound thereon is to be carried to a load for attachment thereto. The cable end which is' attached to the drum is secured thereto in any suitable way.

In operation, to raise a load the knob 36 may be turned to retract the loading pawl 26 from engagement with the ratchet wheel 19, and the manipulative end 54 of the holding pawl 33 is pulled to retract that pawl also from engagement with the ratchet wheel so that the cable 15 may be freely moved to a load. Thereafter, when the knob 36 is turned to load position, the handle 21 may be operated downwardly to win-d the cable 15 onto the drum l7 and thereby lift or pull the load. In this operation the loading pawl 26 engages the ratchet wheel 19 to impart an intermittent motion thereto, while the holding pawl 38 also engages therewith .to prevent back rotation of the drum whenever the handle is stroked upwardly to its initial position preparatory to another downward power stroke.

When it is desired to lower or release a load, the loading pawl 26 is placed in over-riding position by suitably turning the knob 36. A downward swinging movement of the operating handle 21 will then carry the loading pawl 26 freely over the ratchet wheel to the point of its contacting the holding pawl cam 39 which lies in' its path of movement near the end of its downward stroke The loading pawl 26 which is equipped with a laterally extending contact lug then engages the upper face of the elongated cam 39 and advances slidingly thereupon to swing its free end downwardly, thereby increasing the pressure of engagement between the spring free end 48 and the stud 49 to the point of overcoming the tension exerted by the coiled spring 51 and forcing the acting end of the holding pawl 38 away from and out of engagement with the ratchet wheel 19. During this stage of the operation the loading pawl 26 is itself cammed into engagement with the ratchet wheel 19, but at a point which is one tooth removed from the one just vacated by the holding pawl 38 in the same operation. The result is that the winding drum 17 is freed for reverse movement for the distance of one tooth only, while complete control is maintained over the lowering or releasing of the load. safely continued for the full distance required for release of the load. With each disengagement of the holding pawl 38 from the ratchet wheel 19, the spring 46 which is carried wholly within the confines of the cam is elfective to impart a fast snap movement thereto, thereby assuring complete and rapid clearance of the holding pawl 38 from the ratchet wheel at the moment that the loading pawl 26 has been advanced into engagement therewith for controlled lowering of the load.

In Fig. 4 there is illustrated an axial sectional view of the sleeve 22 together with the proximate end portion of the handle 21 which desirably is tubular in form with a grip (not shown) on its free end where power is manually applied. The sleeve is provided with a pair of aligned slots 56 opening out upon opposite ends of the sleeve. At a point diametrically opposite these slots and centrally of the length of the sleeve is a detent which, as shown, comprises outwardly protruding. chambered boss 57 that is internally threaded for engagement with This step by step lowering movement may be threads formed externally upon a bushing 58 wherein is an axial bore. A locking pin 60 terminating in a rounded head 61 at its inner end is extended axially through the bushing, and at its outer end the pin carries a knurled operating button 62 which is conveniently accessible exteriorly of the bushing for manipulation. A compression spring 63 which is coiled around the pin 60 is confined at opposite ends within the boss 57 by the bushing 58 and pin head 61. By the means described the spring acts to bias the head inwardly and into a keeper opening 64 that is formed in the wall of the tubular handle at a point which locks the handle in a predetermined position within the sleeve. In Fig. 4 the curved arrow indicates the direction in which the handle is moved during its power stroke, and when so moved in raising or lowering a load the handle wall on its leading and trailing sides will be subjected concurrently to forces of maximum compression and tension, respectively, at the point Where the handle 21 emerges from the sleeve 22. To facilitate proper rotative positioning of the handle for locking engagement by the detent, I provide a guide element here shown as a screw having its head 65 protruded upon the exterior ofthe handle with its shank 66 extended through its wall for securement thereto. This guide element is located oppositely of the detent and in about the same plane therewith. The screw head is adapted to enter into and advance within either sleeve slot 56. When the guide element has advanced to the end of the slot, the head 61 of the locking pin is concurrently brought to a position directly opposite the keeper opening 64 in the handle wall and into which it is then automatically projected by the spring 63.

One of the features of the present hoist is its relatively light weight. The frame 10, drum 19, lever 20, and pawls 26 and 38 may be produced advantageously from an aluminum alloy with the result that the overall weight may be safely held to less than 10 pounds when endowed with a lifting capacity of more than 3000 pounds. A hollow tubular handle of aluminum alloy assists in holding down the weight and in minimizing the effort required in operation, hence its use is desirable. Such a handle, however, is subject to the maximum disruptive strains at the point where it emerges from the sleeve, and when operated well beyond capacity by careless workmen will tend to bend or break at this point. This is particularly true if the guide element 65 be located upon the handle 21 near either end of the sleeve and upon that side of the handle which trails during the power stroke. According to this invention, the handle may be inserted into either end of the sleeve, and since only one end of the sleeve at a time can act as a fulcrum over which the handle can bend or break when subjected to excessive strain, it is always feasible for the workmen to reverse the handle so that it will enter the sleeve from the end which assure positioning of the screw head 65 on its leading side where only a compressive force is encountered. Due to the presence of the guide element on that side of the handle, its wall is slightly weaker at that point than elsewhere; and therefore more susceptible to disruptive tendencies; but its capacity to withstand deformationor disruption is greater when subjected to a compressive force than to a tension force, hence the importance of safeguarding the handle by assuring positioning of its guide element on the leading side of the handle when the latter is assembled within the sleeve ready for operation. Because the detent is located at a mid point lengthwise of the sleeve, the screw head 65 will act as a guide tocause the handle to move unerringly to proper position whenever it is inserted into either end of the sleeve for operative locking therein, and to limit the distance of entry of the handle into the sleeve to a predetermined point.

I claim:

An operating lever assembly for a winch type of hoist comprising, in combination, a lever having a pawl and ratchet motion-transmitting connection with the winch and mounted for pivotal movement about an axis coaxially thereof, an elongated sleeve, open at both ends, fixedly carried by the lever with the sleeve axis disposed radially of the lever axis, a tubular handle adapted for removable entry into either end of the sleeve with the handle axis disposed radially of the pivotal axis of the lever, a detent carried by the sleeve comprising a locking pin biased for axial movement toward the sleeve axis at a point midway of the sleeve length with the pin axis disposed in a plane transversely of the handle when the latter is entered into the sleeve, and a guide element afiixed to the handle exterior at a point removed from its end entered into the sleeve by a distance approximately equal to the length of the sleeve, the sleeve being provided with a pair of aligned open-ended'slots, one at each end, at a circumferential point oppositely of the locking pin and the handle wall being formed with a keeper opening at a circumferential point oppositely of the guide element and between the two aligned slots, the arrangement being such that the tubular handle, When entered into the sleeve from either end thereof, is free to advance its guide element into the proximate slot thereby automatically to assure entry of the handle into the sleeve for the full length thereof, to locate the keeper opening oppositely of the locking pin for reception thereof, and to assure rotative positioning of the tubular handle Within the sleeve with the guide element disposed upon the leading wall thereof during ensuing power strokes of the handle.

References Cited in the file of this patent UNITED STATES PATENTS 371,652 Witherell Oct. 18, 1887 702,589 Rast June 17, 1902 737,655 Oliver Sept. 1, 1903 1,428,824 Anderson Sept. 12, 1922 1,923,123 Stahlecker Aug. 22, 1933 2,266,643 Kruse Dec. 16, 1941 2,289,818 Winner et al. July 14, 1942 2,377,324 Coffing -1 June 5, 1945 2,470,019 Cofling May 10, 1949 2,738,954 Du Bois Mar. 20, 1956

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