US3198487A - Rapid lowering winch-hoist - Google Patents

Description

1965 DE WITT c. cox 3,198,487

RAPID LOWERING WINCH-HOIST Filed March 17, 1961 3 Sheets-Sheet 1 INV TOR. DEWITT C. X

ATTORNEYS.

g- 3, 1965 DE WlTT c. cox 3,198,487

RAPID LOWERING WINCH-HOIST Filed March 17, 1961 3 Sheets-Sheet 2 ATTORNEYS.

Aug. 3, 1965 DE WITT c. cox

RAPID LOWERING WINCH-HOIST 3 Sheets-Sheet 3 Filed March 17, 1961 INVENTOR. DEWITT C. C O X ATTORNEYS.

United States Patent 3,198,487 RAPID LGWERING WiNCH-HOIST De Witt C. Cox, Flourtown, Pa, assignor to The Lug-All Company, Haverford, Pa., a corporation of Pennsyivania Filed Mar. 17, 1961, Ser. No. 96,486 Claims. (Cl. 254-167) This invention relates to a rapid lowering winch-hoist and, more particularly, to a device which enables the lowering operation to proceed at a considerably faster rate than devices heretofore known.

The use of a winch or a hoist in lifting, opening, etc., operations is wide-spread throughout the world. One type of winch which has achieved great popularity is that of Wallace Patent No. 2,633,328. This device consisted basically of a supportng frame, a cable drum, a ratchet wheel rotatable with the drum, an operating lever pivoted on the axis of the drum and two pawls, the sequential operation of which enabled the winch to carry on its functions. A first pawl is pivoted on the lever and is known as a lever pawl. A second pawl is pivoted on the frame and is known as a holding pawl. Both pawls are adapted to cooperate with the teeth of the ratchet in their operation. The holding pawl is biased into engagement with the ratchet by a spring so constructed that it can be acted upon by the lever pawl to bias the holdingpawl away from the teeth of the ratchet after the lever pawl has engaged a ratchet tooth. As soon as the lever pawl is slightly backed away from the holding pawl spring, the holding pawl can return to its operative position against a ratchet tooth. However, in the meantime, the ratchet has rotated a few degrees under load so that the holding pawl will be seated in the next ratchet tooth upon further rotation of the ratchet under load. In this arrangement, the holding pawl spring, the ratchet tooth and the free end of the lever pawl are arranged in alignment with the free end of the lever pawl adapted to be interposed between the holding pawl spring and the ratchet teeth. 7

It should be noted that the device of Patent No. 2,633,328 lowers a load on a ratchet tooth by ratchet tooth basis. However, in raising thet load, the lever pawl of this device is caused to grasp a ratchet tooth and carry it with it. In raising a load, the holding pawl functions merely to prevent retrograde movement when the stroke of the lever pawl is halted. Thus, the raising operation is usually a quick one proceeding at the rate of several ratchet teeth per lever stroke. The lowering operation, however, is a true ratchet tooth by ratchet tooth operation and thus relatively slow.

It is to be remembered that in the lowering operation, the holding pawl must be released after the lever pawl has been introduced in a ratchet tooth, the holding pawl reintroduced as the lever pawl is withdrawn, etc. For this reason, the lowering operation is, in essence, an intermittent one or, as previously mentioned, a ratchet tooth a great distance, the lowering operation will. be a timeconsuming one and also an annoying one as the lever will have to be cranked many times.

It is, therefore, an object of the present invention to .by ratchet tooth process. Where the load must be lowered provide a winch which can eifect a rapid lowering as well as a rapid raising.

A further object of this invention is to provide a winch which can effect a rapid lowering and yetbe fully safe.

Yet another object of this invention is to provide a .winch which can efiect either a rapid lowering operation or a ratchet tooth by ratchet tooth lowering operation.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following Patented Aug. 3, 13

detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a side elevational View of a Winch to which the rapid lowering mechanism of the present invention has been attached and showing in phantom the lowering position of the lever member as it nears the holding pawl spring, and also showing the raising position of the lever pawl in phantom;

FIG. 2 is a front elevational view of the device of FIG. 1 taken along the lines 22 of FIG. 1;

FIG. 3 is an enlarged fragmentary sectional view taken along the lines 3-3 of FIG. 2 and showing in phantom the key member moved to rapid lowering position. As shown in full line in FIG. 3, the winch is in ratchet tooth by ratchet tooth lowering position;

FIG. 4 is a view similar to FIG. 3 but with the key member so turned that the device of FIG. 3 is in the rapid lowering position with the cam follower positioned against the cam track;

FIG. 5 is a view taken along the lines 55 of FIG. 4;

FIG. 6 is a sectional view taken along the lines 66 of FIG. 5;

FIG. 7 is a view similar to FIG. 4 but wherein the cam follower has entered a cam notch;

FIG. 8 is a view similar to FIG. 6 showing the position g the holding pawl when the winch is in the condition of FIG. 9 is a sectional view taken along the lines 9-9 of FIG. 3;

FIG. 10 is a sectional view taken along the lines Iii-10 of FIG. 3;

FIG. 11 is an exploded perspective view of the unit for conversion between rapid lowering condition and ratchet tooth by ratchet tooth condition, and

FIG. 12 is a detailed view of a portion of the drum, looking at the drum from the side on which the cam is positioned and being partly broken away to show a portion of the ratchet teeth.

Referring now in greater detail to the various figures of the drawings wherein similar reference characters refer to similar parts, a winch-hoist to which the rapid lowering mechanism of the present invention has been attached is generally shown at it in FIG. 1 and FIG. 2.

The winch-hoist basically comprises a frame 12, a cable drum 14, a ratchet wheel 16, lever 1%, lever pawl 20, holding pawl 22, holding pawl spring 24, holding pawl shaft 26 and the conversion unit 28. The basic apparatus of FIGS. 1 and 2, except for the conversion unit 28 and other modifications, is generally disclosed and claimed in United States Patent No. 2,633,328. Drum 14 is mounted for rotation on a shaft 34 which is appropriately journaled in frame 12. Lever 18 is pivotally mounted to rotate about shaft 30 as a center and can be rotated independently of the rotation of the drum 1% or shaft 36. Pivotally mounted on the lever l8'is the lever pawl 26 which is biased by a spring of well-known construction (not shown) into either of the two positions shown in FIG. 1. Holding pawl 22 is pivotally secured to the frame 12 by being pinned to holding pawl shaft 26. This is a departure from Wallace Patent No. 2,633,328 wherein it was not necessary that the holding pawl be pinned to the holding pawl shaft. The spring 24 is of general question-mark shape and is secured to the frame as indicated in FIG. 6. The spring 24 is so constructed that it usually urges the holding pawl 22 in a-generally counterclockwise direction as viewed in FIG. 1 in a first normal bias to move the upper free end of pawl 22 into a ratchet tooth.

Since the holding pawl 22 is pinned to shaft 26, this shaft is also usually urged by the rotative tendency of the pawl 22 in a generally counterclockwise direction by spring 24. The net result is that the holding pawl 22'is urged continually into engagement with a ratchet tooth as shown in FIG. 1.

In use, the hoist is supported by means of upper hook 32 and the load is held by means of lower hook 34 to which is secured rope 36 that is wound on drum 14.

In order to. raise a load, the spring on the lever pawl 26 is so adjusted that the lever pawl engages a ratchet tooth as shown in phantom in FIG. 1. Because a load has ias been applied to hook 3 4, the drum 14 is urged by the weight to rotate in a clockwise direction as shown by arrow 38 in FIG. 1. However, the drum will not rotate in a clockwise direction because the holding pawl 22 firmly abuts against a ratchet tooth to produce a powerful resisting force component. The lever member 18 with lever pawl 2-0 inserted in a ratchet tooth is pulled downwardly or in a counterclockwise direction as viewed in FIG. 1. In doing this, the tendency of the drum 14 to rotate in a clockwise direction is completely overcome and the drum is carried in a counterclockwise direction by the lever pawl 20, thereby winding rope 36 on the drum 14. As the rope 36 is wound on the drum 14, the load is raised. It is to be observed that the holding pawl 22 will glide over the revolving ratchet teeth as the ratchet is being rotated in the direction of arrow 4-8 in FIG. 6 since, in this direction of rotation, the pawl 22 does not interact with the ratchet teeth to produce a component of resistance. It should be noted that a single stroke of the lever 18 from its'upward position of PEG. 1 will cause four or more ratchet teeth to glide past the holding pawl 2 and thus the raising operation is quite rapid.

in order to lower a load secured to hook 34 in accordance with said United States Patent No. 2,633,328, the lever pawl spring is moved so that the lever pawl 29 moves slightly rearwardly or in a clockwise direction to the position shown in full line in FIG. 1. When the lever pawl 26 has been moved to this position, it will stand clear of the ratchet wheel 16 and not directly enter a ratchet tooth as it had done in the raising position. Instead, when the lever 18 is moved downwardly to the phantom position of FIG. 1, the pawl 20 clears the ratchet teeth. It is to be noted that the holding pawl 22 prevents the ratchet 16 from rotating in a clockwise direction in which the ratchet 16 is urged by the load secured to hook 34. i a

The lowering operation proceeds in accordance with said United States Patent No. 2,633,328 by rotating the lever 18 still further downwardly or counterclockwise to the phantom position of FIG. 1. As the lever 18 is still further lowered, the lever pawl 20 contacts the holding pawl spring 24. Holding pawl 22 cannot swing free of the ratchet wheel as its angle of contact with a ratchet tooth produces a powerful component of force which is in excess of the reverse force exerted by holding pawl spring 24.. The holding pawl 22 is released by moving lever member 18 slightwardly down or a few degrees counterclockwise against the load so that holding pawl 22 can swing clear of the now backed away ratchet wheel 16. The load is now entirely transferred to the lever pawl 29. The lever pawl 29 is then slightly backed away from the holding pawl spring and the holding pawl can return in a second normal bias to its operative position aaginst a ratchet tooth. However, in the meantime,

the ratchet wheel has rotated a few degrees under load as the level pawl was backed away. Thus, the holding pawl 22 will be seated in the next ratchet tooth upon further rotation under load. Thus, the ratchet wheel 16 has rotated for a total of one tooth permitting a corresponding lowering of the load.

This operation may be repeated for as many times as is necessary to lower the load a given distance. It is thus seen that the holding function of the holding pawl 22 is temporarily transferred to the lever pawl 26. When the holding function has been returned to holding pawl 22, the ratchet wheel has rotated for one tooth. It is to be noted that lever pawl 26, ratchet wheel 16 and holding pawl spring 24 are in alignment.

The foregoing description characterized in general with the noted exceptions the invention of United States Patent No. 2,633,328. The improvement embodied in the present invention is in enabling the load to be lowered at a much faster rate of several ratchet teeth at a time rather than ratchet tooth by ratchet tooth as previously described.

Reference is now made to FIG. 11 in order to more clearly understand the conversion unit for changing tooth by tooth operation to rapid lowering operation, the unit also functioning as an element of a restraining means for purposes which will be discussed hereinafter.

The unit shown in FIG. 11 basically comprises a plate 42, an actuator 44 and a key 46. The unit of FIG. 11 is associated with the winch 10 in a manner as shown in FIGS. 3, 9 and 10. As shown in FIG. 11, the plate 42 is generally trapezoidal in shape and includes at its upper edge an elongated vertical slot which, as aligned by rivet 104, permits vertical sliding movement of the plate 42 as will be described in greater detail hereinafter. Plate 42 further includes a first opening 56 for anchoring of a pin 84 securing the end of actuator spring '80 as will be discussed in greater detail. The plate-42 further includes a second opening 52 therein for passage of a pin 73 extending from key 46. In addition, a circular cam follower 54 is secured to plate 42 in such a manner as to be ableto rotate about its central shaft 56 which is inserted in the plate 42 as shown in FIG. 10. A generally U-shaped passageway 58 is formed in the lower edge of the plate 42 to produce opposed fingers 6t and 62 and archway 64 through which holding pawl shaft 26 projects for reasons which will soon appear.

The actuator 44 comprises a body section 66 of generally rectangular shape and includes. affixed along its upper edge an apron 68 which extends away from the plate .42 and which merges into a loading edge 70 which is generally similar to the apron 63, but is disposed at right angles thereto. An opening 72 is formed in the loading ledge '70 in order to assist in the anchoring of end 82 of the actuator spring as will soon be discussed. The actuator 44 further includes an elongated upper slot 74 for reception of pin 84 which anchors an end of the actuator spring 80. A lower elongated slot v76 permits pin .78 of the key 46 to be secured to the plate in 'a horizontal direction.

The key 46 is of a generally trapezoidal shape and includes a pin 78 which passes through opening 76 in actuator 44 and is finally threaded in opening 52 in plate 42 (see FIG. 9).

Coil spring 80 possesses an end 82 which is anchored in opening 72 of loading ledge 70. The other end of spring 86 is fastened to a pin 84 which passes through opening 74 in actuator 44 and is then threaded into opening 50in plate 42; It is to be noted that the key 46 may be rotated downwardly to the full line position as shown in FIG. 3. In so doing, a shoulder 86 of key 46 abuts against a positioning shoulder 88. of actuator 44 which extends from actuator 44 in a direction away from .the plate 42 similar to apron 68. As the shoulder 86 of key 46 is forced against the shoulder 88, the actuator 44 is caused to move to the right against the tension of spring 80 to lengthen it to its position of FIG. 3 as end 82 of spring is free to move with actuator 44.

As the key 46 is rotated upwardly or in a clockwise direction as viewed in FIG. 3, the elongated spring 80 returns to its equilibrium position and, in so doing, the actuator 44 is carried by end 82 of spring 8t) to the left as viewed in FIG. 3.

However, as the actuator 44 moves to the left, it is adapted (FIG. 4) to ride upon the surface 96 of heating means 92 (in the form of a pin) when the same is brought to the position of FIG. 4. As previously stated, the actuator can slide horizontally because the openings 74 and 76 and passageway 94 in the actuator 44 are elongated in the horizontal direction. Thus, the upward rotation of the key 46 to the phantom position of FIG. 3 causes the actuator 44 to shift to the left. Since actuator 44 and plate 42 are coupled together for vertical movement by pin '78 of key 46 and by pin 84 of spring 80, plate 42 moves slightly upward with actuator 44 once the holding pawl 22 is disengaged from a ratchet tooth. As cam follower 54 is mounted on plate 42, the cam follower 54 also moves upwardly to close the space 99 between follower 54 and cam track 96. Thus, as cam 96 rotates, cam follower 54 will bear against cam 96.

It should be noted as can be seen in FIG. 11 that the the holding pawl shaft 26 passes through passageways 58 and 94 and thus restricts downward movement of the plate and actuator unit. Upward movement of this unit is restricted by the positioning of the cam follower 54 against cam 96 in a notch 192 of the cam 96 as will be discussed hereinafter.

Returning to FIG. 1, when the lever pawl 20 causes the holding pawl 22 to move against its first normal bias in a clockwise direction in the sense of FIG. 1 or FIG. 5 or away from the ratchet wheel 16, the holding pawl shaft 26 rotates with pawl 22 in a clockwise direction. Let us now assume that the plate actuator unit is brought to the position of FIG. 4 by the previously discussed movement of the key 46 and the automatic retraction of actuator 44 by the spring 86. The lever pawl 20 is now backed away from the holding pawl spring 24 and the holding pawl 22 tends to return into engagement with a ratchet tooth as was previously discurred. Hence, the holding pawl 22 or holding pawl shaft 26 tends to move in a counterclockwise direction in a second normal bias as viewed in FIGS. 1, 4 and 7 and is indicated by the arrows 98 of FIG. 7 in order to return to its position of engagement with ratchet wheel 16. But, holding pawl 22 will not return to ratchet engaging position because of the interaction of cam follower 54 and cam 96 which together with loading ledge 76 and bearing means 92 functions as a restraining means on holding pawl 22.

With the lever pawl 2% in engagement with a ratchet tooth and holding pawl 22 held away, the load on the hook 34 will cause the drum 14 to unwind or move in a clockwise direction, as indicated by the arrow 1% in FlG. 4, when the operator permits the lever 18 to rise to the full line position of FIG. 1. The operator thus controls the load at all times. Such clockwise movement of the drum l4 and the ratchet wheel 16 and the cam 96 which rotate therewith causes a cam notch 102 to be presented to the cam follower 54. As the holding pawl shaft 2% (FIG. 4) is being forced in a counterclockwise direction by the tendency of holding pawl 22 to return to ratchet engaging position (because of spring 24), the bearing means 92 will bear against the loading ledge 7t) of actuator 44 and force the actuator 44 together with the plate 42 upwardly as follower 54 enters notch 1'92. Thus, the upward tendency of the bearing means 92 hearing against loading ledge 70 forces the coupled actuator 44 and plate 42 upwardly a distance permitted by the entry of the cam follower 54 into the cam notch 162. It is to be noted as shown in FIG. that the plate 42 is pinned to the frame 12 by means of a rivet 164 positioned in slot 48 of plate 42 to guide it (with accompanying actuator 44) in vertical sliding movement.

Because the upward movement of actuator 44 is accompanied by a corresponding counterclockwise rotation of holding pawl shaft 26, the holding pawl is rotated also counterclockwise (clockwise in FIG. 6) back into engagement with a tooth of ratchet wheel 16. Thus, entry of follower 54 in cam notch 102 has brought about a restraining of'further rotation of drum 14 in the lowering direction of arrow 38 of FIG. 1. In order to re-initiate the rotation of the drum 14, holding pawl 22 must be released by lever pawl 2i) to cause shaft 26 to rotate in a clockwise direction as viewed in FIG. 7. The cam follower 54 is then withdrawn from its position of FIG. 7 in the cam notch 1432. This is understood when it is remembered that when the cam follower 54 entered the cam notch 192, the holding pawl shaft 26 was permitted to rotate .a bit more in the counterclockwise direction so that the holding pawl could contact a tooth of the ratchet wheel 16. Thus, when the lever pawl 20 contacts the holding pawl spring 24, and the holding pawl 22 is permitted to be biased away from the ratchet in a clockwise direction causing the shaft 26 to rotate clockwise as viewed in FIG. 7. Bearing means 92 on shaft 26 also rotates clockwise or drops from its position of FIG. 7. This permits actuator 44 with plate 42 to drop downwardly to rest on the bearing means 92 in its lowered position.

When plate 42 drops along with actuator 44, follower 54 is no longer positioned in the cam notch 162 but is positioned directly below the cam notch Hi2. Because the holding pawl 22 is held away from the ratchet wheel 16, the drum 14 again rotates (when the operator permits handle 1% to rise) in the direction of arrow liltl in view of the load on hook 34. As the ratchet wheel 16 rotates, the cam follower 54 abuts against cam surface 96. Simultaneously, holding pawl shaft 26 seeks to rotate counterclockwise or in the direction of arrows 98 because the lever pawl 26 no longer contacts spring 255 and, hence, the holding pawl 22 is seeking to return to ratchet engaging position as aforesaid. As soon as another cam notch 1432 is presented to the cam follower 54, it is entered, thereby permitting the actuator and plate unit to be moved upwardly by bearing means 92 as discussed before. When this occurs, the holding pawl shaft 26 rotates in a counterclockwise direction to reset the holding pawl in the ratchet wheel. It has been found that four notches 192 in cam 96 spaced from each other has worked satisfactorily. Thus, if ratchet wheel 16 contains 16 notches, the drum 14 will rotate 4 notches with each stroke of lever 13. It is accordingly observed that cam track 96 effectively prevents holding pawl 22 from engaging a ratchet tooth until a cam notch 132 is entered by cam follower 54 under the pressure of bearing means 92. In other words, the actuator 44 serves to hold the bearin means 92 down thereby preventing the holding pawl 22 from re-engaging.

The unit may be converted to tooth by tooth operation by simply moving key 4'( downwardly to the full line position of FIG. 3. In doing this, shoulder 8-5 of key 46 overcomes the tension of spring 89 and forces the actuator 44 to the right to its position of FIG. 3. In assuming this position, the lower edge of the loading ledge 76 rides or otherwise clears the surface 94 of bearmg means 92 and finally drops down and beyond the bearing means 92 as viewed in FIG. 3. Thus, when the holding pawl shaft 26 now rotates in any direction, the pin 92 does not abut or touch against the loading ledge 7% Hence, the actuator 44 remains in the position of FIG. 3. Thus, the cam follower 54 is not urged upwardly against cam 96, and the holding pawl 22. is not restrained from immediate re-engagement with a ratchet tooth when the lever pawl Ztl is pulled away from spring 24. Hence, the tooth by tooth lowering can proceed or the operation can be converted to rapid lowering as desired by the user.

As an added feature a tap hole (not shown) may be formed in plate 42 to extend therein from the lower confines of the slot 43. A small coil spring is inserted in the tap hole in such a manner that the upper end thereof presses against rivet and thus the movement of the upper end of the coil spring is limited by the fixed positioning of rivet 164. The lower end of the coil spring bears into the plate 42 which is movable relative to the rivet 184. Hence, the small coil spring tends to force plate 4-2 downward to insure that cam follower 54 will be held away from the cam track. As the force of the coil spring is small relative to the force of holding pawl spring 24, the small coil spring will not hinder the rotation of holding pawl shaft 2-6 in the operation of the rapid lowering mechanism.

Obviously many modifications and variations of the present invention are possible in the light of the above eachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed as the invention is:

1. A rapid lowering winch adapted to move a load comprising a supporting frame, a cable drum, a ratchet wheel rotatable with said drum and having a plurality of ratchet teeth including first and second ratchet teeth, an

operating lever associated with said drum, a lever pawl pivotally secured to said lever, a lever pawl pring for biasing said lever pawl in a chosen direction, a holding pawl pivotally secured to said frame, a holding pawl spring biasing said holding pawl into normal ratchet engaging position with said first ratchet tooth, said holding pawl spring, ratchet teeth and the free end of said lever pawl being arranged in alignment, said holding pawl spring being adapted to be acted upon by said lever pawl to bias said holding pawl away from its normal ratchet engaging position during lowering after said lever pawl has been moved into ratchet engaging position with said second ratchet tooth, said holding pawl being again normally biased by said holding pawl spring when said holding pawl spring is no longer acted upon by said lever pawl, and restraining means for rapid lowering associated with said holding pawl, to prevent said holding pawl from being again normally biased by said holding pawl spring for a predetermined limited rotation under load of said ratchet wheel of at least two of said ratchet teeth thereby to restrain said holding pawl from its normal ratchet engaging position for said predetermined rotation of at least two of said ratchet teeth, and said restraining means including cam means secured to said drum, a shaft rotatively mounted on said frame, said holding pawl being fixedly secured to said shaft, said restraining means being associated with said shaft, said shaft including bearing means.

2. The invention of claim 1 further including a plate adapted to restrain the rotation ofsaid holding pawl shaft, said plate including a loading ledge and a cam follower member, said loading ledge adapted to be contacted by said bearing means to motivate said plate, said cam follower member being carried along with said plate and a cam including a cam track and cam notches, said jcarn follower being adapted to bear against said cam track and adapted to be positioned in said cam notches whereby when said cam follower is positioned against said cam track, said bearing means are restrained from movement and whereby when said cam follower moves into one of said cam notches, said bearing means also move.

3. The invention of claim 2 wherein said cam has four notches.

The invention of claim 1 further including a plate, an actuator, a key, and a cam including a cam track and cam notches, said plate including a cam follower member, said actuator being secured to said plate for movement therewith in a'first direction and for movement relative thereto in a second direction, said actuator being biased with respect to said plate against said second direction, said bearing means being adapted to be contacted by said actuator, said bearing means being biased to urge said actuator, plate and cam follower in said first direction, said cam follower being urged against said cam track and being adapted to be positioned in one of said cam notches whereby when said cam follower is positioned against said cam track, said actuator and plate are restrained from movement in said first direction and whereby when said cam follower moves into one of said cam notches, said actuator and plate may move in said first direction, said key being secured to said plate and being adapted to force said actuator away from its biased position so as not to be contacted by said bearing 5. The invention of claim 4 wherein said cam has four notches.

References Cited by the Examiner UNITED STATES PATENTS 2,633,328 3/53 Wallace 254164- 2,741,927 4/56 Hollander 254l64 X 2,793,535 5/57 Stump 74l52 2,913,224 11/59 Uhlig 254-167 SAMUEL F COLEMAN, Primary Examiner.

LELAND M. MARTIN, JOSEPH P. STRIZAK,

RAPHAEL M. LUPO, Examiners.

Claims (1)

1. A RAPID LOWERING WINCH ADAPTED TO MOVE A LOAD COMPRISING A SUPPORTING FRAME, A CABLE DRUM, A RACKET WHEEL ROTATABLE WITH SAID DRUM AND HAVING A PLURALITY OF RATCHET TEETH INCLUDING FIRST AND SECOND RATCHET TEETH, AN OPERATING LEVER ASSOCIATED WITH SAID DRUM, A LEVER PAWL PIVOTALLY SECURED TO SAID LEVER, A LEVER PAWL SPRING FOR BIASING SAID LEVER PAWL IN A CHOSEN DIRECTION, A HOLDING PAWL PIVOTALLY SECURED TO SAID FRAME, A HOLDING PAWL SPRING BIASING SAID HOLDING PAWL INTO NORMAL RATCHET ENGAGING POSITION WITH SAID FIRST RATCHET TOOTH, SAID HOLDING PAWL SPRING, RATCHET TEETH AND THE FREE END OF SAID LEVER PAWL BEING ARRANGED IN ALIGNMENT, SAID HOLDING PAWL SPRING BEING ADAPTED TO BE ACTED UPON BY SAID LEVER PAWL TO BIAS SAID HOLDING PAWL AWAY FROM ITS NORMAL RATCHET ENGAGING POSITION DURING LOWERING AFTER SAID LEVER PAWL HAS BEEN MOVED INTO RATCHET ENGAGING POSITION WITH SAID SECOND RATCHET TOOTH, SAID HOLDING PAWL BEING AGAIN NORMALLY BIASED BY SAID HOLDING PAWL SPRING WHEN SAID HOLDINGING PAWL SPRING IS NO LONGER ACTED UPON BY SAID LEVER

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