US3109628A - Hoisting device - Google Patents

Description

Nov. 5, 1963 P. K. EELLS EI'AL 3,109,628

HOISTING DEVICE Filed May 3, 1961 6 Sheets-Sheet 1 EN TOR5 A Tram 12y Nov. 5, 1963 P. K. EELLS ETAI. 3,109,628

HOISTING DEVICE Filed May 3. 1961 6 Sheets-Sheet 2 Pig 2.

mmvrons PAUL K. EELLS wmum FWRIGHB-JR.

ZJQ/W Nov. 5,- 1963 P. K. EELLS ETAL 3,109,623

HOISTING DEVICE Filed May 3, 1961 6 Sheets-Sheet 3 INVENTORS PAU L K- E E LLS Nov. 5, 1963 P. K. EELLS EIAL 3,109,628

HOISTINGDEVICE Filed May 3, 1961 6 Sheets-Sheet 4 PS-4m j 23; y

ZZZ

INZENTORS PAUL K. EhLLS it v yuuAm E WRIGHTMR.

ZWWW

A TTORNIF/ Nov. 5, 1963 P. K. EELLS ElAL 3,109,628

HOISTING DEVICE Filed May 3, 1961 6 Sheets-Sheet 5 Fig 5 ZZZ Z4 INV EN T0115 PAUL K. EE LLS A Tram/a & y yl LLIAM F? WRlGHT,dR.

1963 P. K. EELLS ETAL 3,10 ,628

HOISTING DEVICE Filed May 3, 1961 6 Sheets-Sheet 6 INVENTORE PAUL K. EELLS WILLIAM F. wRlsHTflJR.

United States Patent 3,109,628 IIGISTING DEVIQE Paul If. Eeiis, Lisbon, and Wiiiiam E. Wright, .Iru, Saiem, Qhio, assignors to 'Ihe Wright huffing Wheel Company, Lisbon, Ghio Fiied May 3, 1961, 581'. No. 116,221 14 tiiaims. (Cl. 254-167) The present invention relates to a manually operated force applying device, more panticularly to a manually operated hoisting device and the like, and the principal object of the invention is to provide new and improved devices of such character.

As will subsequently appear, the present invention 0perates on the well-known ratchet principle which has long been used for devices of the present type. Prior art devices, however, can be divided into two general types; i.e., those which function satisfactorily but which are complicated and expensive to manufacture, and those which, while low in manufacturing cost, are extremely limited in their force applying, or weight lifting, capacity. A further difficulty of many prior ant designs is that many employ complex springs or other delicate parts which frequently break. In contrast, the present invention provides a simple light-weight structure which, in its present commercial form, weighs but twelve pounds yet is capable of lifting two thousand pounds with an applied force of but eighty pounds. The structure is relatively low in cost of manufacture and employs but three springs, each of simple, long-life design and app-lication. Thus the device can be sold at a relatively low price and is practically maintenance-free. These and other advantages will readily become apparent from a study of the following description and from the drawings appended hereto.

In the drawings accompanying this specification and forming a part of this application, there is shown, for purpose of illustration, an embodiment which the invention may assume, and in these drawings:

FIGURE 1 is a sectional view taken through a preferred form of the invention showing the position of parts in one stage of operation and generally corresponding to the line 1-1 of FIGURE 2,

FIGURE 2 is a sectional view generally corresponding to the line 2-2 of FIGURE 1,

FIGURE 3 is a fragmentary, exploded perspective view of certain details,

FIGURE 4 is a view similar to FIGURE 1 but illustrating another stage of operation,

FIGURES 5 and 6 are views similar to FIGURE 4 but illustrating successive stages of operation,

FIGURE 7 is an enlarged, fragmentary view of a portion of a detail seen in FIGURE 2,

FIGURE 8 is a reduced size sectional view of a modified detail, and

FIGURE 9 is an enlarged, fragmentary view of a portion of the detail seen in FIGURE 8.

With reference to FIGURES 1 and 2, the device, in brief, comprises a frame It} which rotatably supports a drum 11 having axially spaced, radially outwardly extending flange portions one of which has a toothed periphery forming a ratchet wheel 12. A shaft 13 extends axially through the drum, the latter being pinned or otherwise secured thereto for unitary rotation therewith. A flexible cable 14 has one end anchored to the drum, the opposite end of the cable carrying a suitable hook (not shown) for attachment to the body to be lifted.

Pivotally carried by the frame is a holding pawl 15 which is spring-biased to engagement with the ratchet wheel. This pawl, as seen in FIGURE 1, normally prevents rotation of the ratchet wheel in a clockwise direction. Pivotally carried by axial extensions of shaft 13 is an arm 16 which in turn pivotally supports an actuating pawl 17. This pawl is selectively spring-biased either toward engagement with the ratchet wheel, as seen in FIGURE 1, when the latter is to be rotated in a counter-clockwise direction or away from engagement with the ratchet wheel, as seen in FIGURE 4, when the latter is to be rotated in a clockwise direction. As will later be disclosed, oscillation of handle :16 about shaft 13 will cause rotation of the ratchet wheel and consequently rotation of the drum in a direction to wind or unwind the cable therefrom to thus respectively raise or lower the load attached to the free end of the cable.

Turning now to a more detailed description of the various parts and referring first to FIGURE 2, frame 10 is formed of two, opposite hand portions 19.1 and 10.2 each having respective central portions 10.3 and 18.4 and respective off-set leg portions 1&5 and 1416. Frame portions 10.1 and 141.2 are removably secured together by means of bolts 18 and each central portion is recessed to receive a headed pin 1h which is rotatably clamped therebetween. Although not shown, a hook or other device may be secured to the upper end of pin 19 for connecting the hoist device to a suitable support. Each frame portion 10.11, 10.2 is ribbed at 1%.? for added strength and the offset portions 16.5, 18.6 are spaced from each other, as shown, and each carries a suitable bearing 26 for the previously mentioned shaft 13. While sleeve bearings have been shown for simplicity, ball or other anti-friction bearings will be used in the production device.

Still referring to FIGURE 2, drum 11 is disposed between the frame offset portions 10.5, 10.6 with the ratchet wheel 12 adjacent the latter. The ratchet wheel portion of the drum provides an axially extending shoulder 21 on which is rotatable an actuating disk 22 (see also FIGURE 1) later to be described in detail. The previously mentioned holding pawl 15 is trunnioned between the frame offset portions 135, 10.6 in spaced relation to the shaft 13, each frame portion having an apertured ear 1th; protruding therefrom for rotatably receiving respective reduced end portions 15.1, 15.2 of this pawl. An off-set lug 15.3 on pawl 15 provides an anchor for one end of a torsion spring 23 which is wound about pawl end portion 151. The other end of spring 23 is anchored to the adjoining frame portion 16.5 whereby the spring yieldably biases the tooth portion 15.4 of the pawl to engagement with the ratchet wheel. For a purpose to appear, pawl 15 has an upstanding lug 15.5 which provides for ready manual actuation thereof and the pawl has a flat surface 15.6 which is best seen in FIGURE 1.

Turning now to the previously mentioned arm 16 and still referring to FIGURES l and 2, this arm is similar to the frame It in that it comprises a pair of opposite hand portions 16.1, 16.2 each having a respective central portion 15.3, 16.4 and respective off-set portions 16.5, 16.6. Central arm portions 16.3, 16.4 are adapted to be secured together by means of bolts 24, such portions being recessed to receive one end of an elongated tube 25 which is clamped therebetween. Although not shown, the free end of tube 25 is adapted to be gripped by the operator to effect reciprocation of the arm 16 about the axis of shaft 13. Off-set arm portions 16.5, 16.6 are spaced apart to spanthe off-set frame portions 1&5, 1116 and each is apertured to rotatably pass respective ends of shaft 13. Suitably secured to the latter for unitary rotation therewith is a knob 26 whose function will later appear.

Extending between the arm portions 16.5, 16.6 is a shaft 27 (see also FIGURE 3) on which the actuating pawl 17 is pivoted. In addition to a tooth portion 17.1 which aligned with and adapted to engage the ratchet wheel, pawl 17 has a radially outwardly extending lug 17.2 which is spaced both radially of the tooth 17.1 and axially therefrom for alignment with a portion ofthe previously mentioned disk 22 for a purpose to be seen. De-

pending from the actuating pawl 17 (in the position of parts as viewed in FIGURES 1 and 3) is a ring-like portion 17.3 whose interior, annular surface 17.4 provides opposed, facing-abutments for a purpose to appear.

ing radially outwardly of the stub shaft 28 is an actuating finger 28.2 by means of which the shaft 28 may be reciprocated with respect to the arm portion 16.6 through an arc of approximately one hundred eighty degrees for a purpose to appear.

Slidable in a transverse bore of the stub shaft 28 is a cup-like plunger 29 whose closed end bears against the internal, annular pawl surface 17.4. A helical spring 3% yieldably biases the plunger to engagement with the pawl surface 17.4 to yieldably bias the pawl to the position seen in FIGURE 1 wherein its tooth portion 17.1 is engaged with the ratchet wheel.

With the construction thus far described and with the parts positioned as seen in FIGURE 1, if arm 16 is rotated in a counter-clockwise direction, actuating pawl will be swung in an arcuate path therewith. Since this pawl is engaged with a tooth of the ratchet wheel, the latter and thus the drum will be rotated in a counter-clockwise direction to wind the cable on the drum. Upon rotation aforesaid of the ratchet wheel, the holding pawl 15 will be sprung outwardly to allow a ratchet tooth to pass thereunder and will immediately spring back to prevent reverse rotation of the ratchet wheel. As soon as the ratchet wheel has been rotated sufliciently to allow a tooth thereof to pass under the holding pawl 15 as above described, handle 16 may then be rotated in a clockwise direction to the position illustrated in FIGURE 1. It will be understood that during such clockwise rotation of the handle, pawl 17 will spring over a ratchet wheel tooth and will be immediately returned by spring 30 to engagement with the next adjoining ratchet wheel tooth. The above procedure will be repeated as many times as necessary until the load at the end of cable 14 has been lifted step by step (or more accurately, tooth by tooth) the required amount.

From the foregoing it will be understood that the previously mentioned disk 22 serves no function during load elevation, instead, such disk functions only when the load is to be lowered. Accordingly, the plate and its associated parts will next be described in detail prior to a disclosure of the load-lowering operation.

With reference to FIGURES 2 and 4, disk 22 provides upper and lower bosses 22.1 and 22.2 in opposed relation. Slidably carried by the upper boss 22.1 is a headed pin 31 biased to the extended position seen in FIGURE 4 by means of a helical spring 32 disposed within the boss cavity in which the pin head is slidable. Pin 31 forms an abutment for a purpose to appear. The spring 32 is retained in the cavity by means of a keeper pin 33. Formed on the boss 22.1 is a projection 22.3 which engages with an abutment 10.9 formed on the frame portion 10. 6 to 7 limit disk rotation. As seen in FIGURE 4, the free end of pin 31 is adapted to engage the holding pawl flat 15.6. beneath the pivotal axis of this pawl, for a purpose to be seen.

The lower disk boss 22.2 is provided with a threaded aperture for receiving a screw 34 whose end opposite its head provides an abutment disposed in the arcuate path of movement of the actuating pawl lug 17.2. A lock nut 85 retains the screw 34 in the desired position of adjustment relative to the boss 22.2.

When the load supported by cable 14 is to be lowered, stub shaft 28 will be rotated by means of finger 28.2 from the position seen in FIGURE 1 to the position seen in FIGURE 4. Plunger 29 and spring 36 will thus bias the actuating pawl 17 to the full-line position seen in FIGURE 4 wherein its tooth 17.1 clears the ratchet wheel. If the arm 16 is now rotated in a counter-clockwise direction from the full-line position seen in FIGURE 4 to the phantom-line position seen therein, actuating pawl lug 17.2 will engage the end of screw 34 to thus pivot the actuating pawl about its shaft 27, against the urging of the spring 31), to engagement with the ratchet wheel. Note, however, that the actuating pawl has not yet engaged with a ratchet wheel tooth and thus the entire load remains supported by the holding pawl 15.

Further movement of the arm 16 in a counter-clockwise direction from the phantom line position seen in FIGURE 4 to the position seen in FIGURE 5 will cause the pawl tooth 17.1 to engage the adjoining ratchet wheel tooth whereby the actuating pawl will be in position to pick up the load supported by the cable. It will be noted that the movement aforesaid has caused counter-clockwise rotation of the disk 22 since the actuating pawl lug 17.2 is engaged with the disk screw 34, such disk movement being permitted since the path 31 has moved inwardly of the boss 22.1 causing deflection of spring 32. The pin 31 and spring 32 thus function as a resilient, lostmotion connection between the two pawls. Pawl 15 still remains in the position illustrated, despite the pressure exerted by the spring 32 tending to force the pawl away from ratchet Wheel engagement, since this pawl continues to support the load and thus cannot be shifted about its ivot.

P Further movement of arm 16 in -a counter-clockwise direction from the position seen in FIGURE 5 to the position seen in FIGURE 6 will cause the actuating pawl to pick up the load and rotate the ratchet wheel slightly in a counter-clockwise direction. As soon as the ratchet wheel has rotated sufficiently to unlock the holding pawl tooth 15.4 therefrom, the force exerted by plunger 31 will urge the holding pawl to the position illustrated in FIGURE 6 wherein it is clear of the ratchet wheel. At this time, the entire load is supported by the actuating pawl 17.

'From the position seen in FIGURE 6, handle 16 may now be rotated in a clockwise direction to permit clockwise ratchet wheel rotation and consequent lowering of the load. During initial clockwise arm rotation and consequent similar rotation of the disk 22, pin 31, under the urging of spring 32, will continue to maintain the holding pawl 15 away from ratchet wheel engagement until the ratchet wheel has moved sufficiently in a clockwise direction that the wheel tooth previously engaged by the holding pawl has passed therebeneath. At such time, there will have been sufiicient clockwise rotation of disk 22 that pin 31 will have reached the end of its outward travel and thus will be unable to exert further force to maintain the holding pawl away from ratchet wheel engagement. Accordingly, the holding pawl will once again be biased toward the ratchet wheel by means of the torsion spring 23. Further clockwise movement of the arm 16 will continue until the holding pawl is seated against the next ratchet wheel tooth and supports the entire load. At such time, that is with the holding pawl supporting the load, slight further clockwise movement of the arm will unlock the actuating pawl from the ratchet wheel tooth so that the plunger 29 and the spring 30 will bias the actuating pawl away from ratchet wheel engagement to the position seen in FIG- URE 4. The above precedure will be repeated as many time as necessary until the load has been lowered toothby-tooth the required amount.

When the cable 14 is to be rapidly wound upon the drum, as when no load is attached thereto or when slack is to be taken out of the cable, it is only necessary to rotate the drum and the ratchet wheel in a counter-clockwise direction by means of the knob 26. Similarly, the knob 26 may be employed to rotate the drum in a clockwise direction to unwind cable therefrom when no load is attached thereto. Such operation, however, requires that the stub shaft 28 be positioned as seen in FIGURE 4 so as to bias the actuating pawl away from the ratchet wheel and also requires that the holding pawl be disengaged from the ratchet wheel against the urging of the torsion spring 23 by the application of pressure to the holding pawl lug 15.5.

While the foregoing construction functions very well, it has been'found that certain problems arise when a conventionally constructed winding drum, such as seen in FIGURE 2, is employed. Simply defined, and with reference to FIGURE 7 wherein the drum 11 is fragmentarily seen in enlarged section, the problem is as follows: During elevation of a load and when the cable 14 has been wound to the end of the drum, the next few turns of the cable will pile up on one another, as illustrated, instead of smoothly reversing and winding the next cable layer upon the preceeding one. Eventually, such turns will fall into place as indicated by the arrows and phanton lines; however, when they do, the the load will drop a perceptible amount.

This dropping of the load causes heavy stresses on the cable and the hoist parts and since it is unexpected, can also be quite dangerous during certain operations. This tendency of the cable to pile up at the drum ends is aggravated by the fact that since the hoist is suspended a single point by its supporting hook (not shown), the axis of the drum will tilt when the cable extends from a drum end. This is seen in FIGURE 7 wherein A illustrates a plane normal to the drum axis when the cable is centered beneath the hook and B illustrates such plane when the cable is at (in the position of parts shown) the left end of the dru,

As viewed in FIGURE 8 wherein like parts are identified by the same reference characters as before but with the sufiix (1 added, a highly effective solution to the above-mentioned problem lies in forming a dished surface 3d, 37 in the facing surfaces of respective flanges at respective ends of the drum 11a. Furthermore, the annular drum surface is tapered at 38 from approximately the center line A of the supporting hook, such tapered drum surface being larger in diameter at its end adjacent the flange than at the center line of the hook.

Operation of the improved drum 11a is as follows, reference being made to the enlarged fragmentary section FIGURE 9: As the cable 14a is wound upon the drum and reaches the left (in the position of parts shown) end thereof, the first turn 14.1 of the next cable layer will be crowded against the adjoining flange surface as shown. The next turn 14.2 of the cable will, however, be Wound alongside turn 14.1 instead of on top of the latter, as frequently happened before, because of the following reasons. Firstly, the angularity of the dished surface 36 will crowd the turn 14.2 to the right so that it cannot obtain sufficient support to remain on the turn 14.1. Secondly, as a result of the tapered drum surface 38, the cable turn 14.2 will not be required to climb up hill to reach the position seen in FIGURE 9 even though the drum is tilted so that a plane normal to its axis is shifted to the position seen at B from its normal position seen at A.

It will be understood that successive cable turns will lie along the preceding turns until the cable reaches the right end of the drum whereupon the cable will begin to wind a third layer in the same manner as the second layer was commenced. It is also to be understood that since the centerline A of the hook (see also FIGURE 8) is not centered between the drum flanges but is off-set toward the ratchet wheel 112a, it has been found unnecessary to taper the right-hand end of the drum; however, under different circumstances, it may be found desirable to also taper this drum end.

While the present device has been disclosed for use in vertically elevating and lowering a load, it will readily be apparent that it is not limited to such use but can also be used for pulling a load in a plane other than vertical.

In view of the foregoing, it will be apparent to those skilled in the art that we have accomplished at least the principal object of our invent-ion and it will also be apparent to those skilled in the art that the embodiments herein described may be variously changed and modified, without departing from the spirit of the invention, and that the invention is capable of uses and has advantages not herein specifically described; hence it will be appreciated that the herein disclosed embodiments are illustrative only, and that our invention is not limited thereto.

We claim:

1. A hoisting device and the like comprising a frame, a ratchet wheel pivotally supported by said frame, a first pawl supported by said frame for engagement with said ratchet wheel to prevent rotation thereof in one direction and such pawl being pivotable away from engagement with said ratchet wheel to provide for rotation thereof in said one direction, a second pawl swingable in an arcuate path of travel about the axis of rotation of said ratchet wheel and pivotable toward and away from engagement therewith, resilient means yieldably biasing said second pawl away from ratchet wheel engagement, a first abutment for pivoting said second pawl to engagement with said ratchet wheel against the force exerted by said resilient aneans when said second pawl is swung in its arcuate path in one direction to abutment engagement, a second abutment engageable with said first pawl for pivoting the latter away from engagement with said ratchet wheel upon further movement of said second pawl in the direction aforesaid, and a resilient lost-motion connection interposed between said labutments to delay return of said first pawl to engagement with said ratchet wheel following its disengagement therefrom and subsequent reverse movement of said second pawl in its arcuate path of travel.

2. The construction of claim 1 wherein said second abutment comprises a spring-loaded plunger providing a resilient lost-motion structure which delays return of said first pawl to engagement with said ratchet wheel following its disengagement therefrom and subsequent reverse movement of said second pawl in its arcuate path of travel.

3. The construction of claim 2 wherein a helical spring is engaged with said plunger to yieldably bias the latter to a predetermined position for engagement with said first pawl.

4. The construction of claim 1 wherein said first pawl has a projection extending radially of such pawls pivotal axis for manual pawl movement away from ratchet wheel engagement to provide for rapid non-ratcheting rotation of said ratchet wheel.

5. The construction of claim 4 wherein said first pawl projection is on the opposite side of the pawlaxis from that pawl portion which engages said ratchet wheel.

6. A hoisting device and the like comprising a frame, a ratchet wheel pivotally supported by said frame, a first pawl supported by said frame for engagement with said ratchet wheel to prevent rotation thereof in one direction and such pawl being pivotable away from engagement with said ratchet wheel to provide for rotation thereof in said one direction, a second pawl swings-ole in an arcuate path of travel about the axis of rotation of said ratchet wheel and pivotable toward and away from engagement therewith, resilient means yieldably biasing said second pawl away from ratchet wheel engagement, and an actuating member adjacent said ratchet wheel and pivotable about the rotational axis thereof, said member having a first abutment for pivoting said second pawl to engagement with said ratchet wheel against the force exerted by said resilient means when said second pawl is swung in its arcuate path in one direction to engagement with said first abutment and said member having a second abutment for pivoting said first pawl away from engage ment with said ratchet wheel upon further movement of said second pawl in the direction aforesaid and consequent rotation of said actuating member with said second pawl.

7. The construction of claim 6 wherein said first abutment is shiftable relative to said actuating member to vary the place of engagement of said second pawl therewith along the latters path of travel. 8. The construction of claim 6 wherein said second abutment comprises an axially movable plunger biased to a predetermined position for engagement with said first pawl by means of a helical spring, said plunger and said spring providing a resilient lost-motion structure which delays return of said first pawl to engagement with said ratchet wheel following its disengagement therefrom and subsequent reverse movement of said second pawl in its arcuate path of travel.

9. A hoisting device and the like comprising a frame, a ratchet wheel pivotally supported by said frame, a first pawl supported by said frame for engagement with said ratchet wheel to prevent rotation thereof in one direction and such pawl being pivotable away from engagement with said ratchet wheel to provide for rotation thereof in said one direction, an arm pivotable about the rotational aXis of said ratchet wheel, a second pawl pivotally carried by said arm for movement toward and away from ratchet wheel engagement and providing facing abutments off-set to one side of its pivotal axis, said second pawl being bodily shiftable with said arm for movement in an arcuate path of travel about said ratchet Wheel axis, a selector member pivotally carried by said arm intermediate said second pawl abutments, a plunger slidably carried by said selector member for movement transversely of the latters pivotal axis, and a helical spring yieldably biasing said plunger to engagement with one or the other of said second pawl abutments, depending upon the position to which said selector member is pivoted, to yieldably bias said second pawl toward or away from ratchet wheel engagement.

10. The construction of claim 9 wherein said second pawl has an arcuate surface, opposed portions of which provide said facing abutments.

11. A hoisting device and the like comprising a frame having spaced portions in side-by-side relation, a ratchet wheel pivotally supported by and disposed intermediate said spaced frame portions, a dnum in side-by-side relation with said ratchet wheel and rotatable therewith, a cable wound upon said drum and adapted to be attached to a weight to be lifted, a first pawl pivotally supported between said frame portions for engagement with said ratchet wheel to prevent rotation thereof in a direction to unwind said cable from said drum and such pawl being movable about its pivot away from engagement with ratchet wheel to provide for rotation thereof in the direction aforesaid, a torsion spring disposed about the axis of said pawl and having a finst part engaged with the latter and a second part engaged with an adjoining frame portion to yieldably bias said pawl ratchet wheel engagement, an actuating arm having spaced portions in side-by-side relation for receiving said frame therebetween and said arm being pivotable about the rotational axis of said ratchet wheel, a second pawl pivotally supported between said arm portions for movement toward and away from ratchet wheel engagement and p'noviding facing abutments off-set to one side of its pivotal axis, said second pawl being bodily shiftable with said arm for movement in an arcuate path of travel about said ratchet wheel axis, a selector member pivotally carried by one of said arm portions intermediate said second pawl abutments, a plunger slidably carried by said selector member for movement transversely of the latters pivotal axis, a helical spring yieldably biasing said plunger to engagement with one or the other of said second pawl abutments, depending upon the position to which said selector member is pivoted, to yieldably bias said second pawl away from or toward ratchet wheel engagement to respectively provide for ratchet wheel rotation in a direction to unwind said cable from said drum or rotation in the oppostie direction, an actuating member intermediate said ratchet wheel and the adjoining frame portion and piv-otable about the rotational axis of said ratchet wheel, a first abutment carried by said actuating member for pivoting said second pawl to engagement with said ratchet wheel against the urging of said selector member plunger when said second pawl is swung in its arcuate path in one direction to engagement with the first actuating member abutment, and a second abutment carried by said actuating member and engageable with said first pawl for pivoting the latter away from ratchet wheel engagement upon further movement of said second pawl in the direction aforesaid and consequent rotation of said actuating member with said arm.

12. The construction of claim 11 wherein said second actuating member abutment is provided by an axially movable plunger and wherein a helical spring is engaged with said plunger to yieldably bias the latter to a predetermined position with respect to said actuating member for engagement with said first pawl, said plunger providing a resilient lost-motion structure which delays return of said first pawl to engagement with said ratchet wheel following its disengagement therefrom and subsequent reverse movement of said arm, said second pawl, and said actuating member.

13. The construction of claim 12 wherein said first actuating member abutment is shiftable relative to said actuating member to vary the place of engagement of said second pawl therewith along the latters path of travel.

14. A hoisting device'and the like comprising a frame, a ratchet Wheel pivotally supported by said frame, a first pawl supported by said frame for engagement with said ratchet wheel to prevent rotation thereof in one direction and such pawl being pivotable away from engagement with said ratchet wheel to provide for rotation thereof in said one direction, a second pawl swingable in an arcuate path of travel about the axis of rotation of said ratchet wheel and pivotable toward and away from engagement therewith, and resilient means formed of a spring-loaded plunger spaced radially of the pivotal axis of said second pawl and acting along a line transverse to such pawl axis to yieldably bias said second pawl selectively toward and away from ratchet wheel engagement.

References Cited in the file of this patent UNITED STATES PATENTS 2,581,716 Sasgen Jan. 8, 1952 2,620,996 Le Bus Dec. 9, 1952 2,633,328 Wallace Mar. 31, 1953 2,738,954 Du Bois Mar. 20, 1956 2,854,852 Clark Oct. 7, 1958 2,884,226 Palka Apr. 28, 1959 2,890,857 Hoffman June 16, 1959 2,913,224 Uhlig Nov. 17, 1959 2,927,771 Clark Mar. 8, 1960 2,967,046 Ratcliff Ian. 3, 1 961

Claims (1)

1. A HOISTING DEVICE AND THE LIKE COMPRISING A FRAME, A RATCHET WHEEL PIVOTALLY SUPPORTED BY SAID FRAME, A FIRST PAWL SUPPORTED BY SAID FRAME FOR ENGAGEMENT WITH SAID RATCHET WHEEL TO PREVENT ROTATION THEREOF IN ONE DIRECTION AND SUCH PAWL BEING PIVOTABLE AWAY FROM ENGAGEMENT WITH SAID RATCHET WHEEL TO PROVIDE FOR ROTATION THEREOF IN SAID ONE DIRECTION, A SECOND PAWL SWINGABLE IN AN ARCUATE PATH OF TRAVEL ABOUT THE AXIS OF ROTATION OF SAID RATCHET WHEEL AND PIVOTABLE TOWARD AND AWAY FROM ENGAGEMENT THEREWITH, RESILIENT MEANS YIELDABLY BIASING SAID SECOND PAWL AWAY FROM RATCHET WHEEL ENGAGEMENT, A FIRST ABUTMENT FOR PIVOTING SAID SECOND PAWL TO ENGAGEMENT WITH SAID RATCHET WHEEL AGAINST THE FORCE EXERTED BY SAID RESILIENT MEANS WHEN SAID SECOND PAWL IS SWUNG IN ITS ARCUATE PATH IN ONE DIRECTION TO ABUTMENT ENGAGEMENT, A SECOND ABUTMENT ENGAGEABLE WITH SAID FIRST PAWL FOR PIVOTING THE LATTER AWAY FROM ENGAGEMENT WITH SAID RATCHET WHEEL UPON FURTHER MOVEMENT OF SAID SECOND PAWL IN THE DIRECTION AFORESAID, AND A RESILIENT LOST-MOTION CONNECTION INTERPOSED BETWEEN SAID ABUTMENTS TO DELAY RETURN OF SAID FIRST PAWL TO ENGAGEMENT WITH SAID RATCHET WHEEL FOLLOWING ITS DISENGAGEMENT THEREFROM AND SUBSEQUENT REVERSE MOVEMENT OF SAID SECOND PAWL IN ITS ARCUATE PATH OF TRAVEL.

Images