US2552928A - Scaffold winch - Google Patents

Description

May 15, 1951 J. M. BENSON A 2,552,928

SCAFFOLD WINCH Filed 001;. 21, 1946 Z5 57 I: Z4

Jill-Benson MMM Patented Mayv 15, 1`95 SCAFFOLD WINCH Jesse M. Benson, Concord, Tenn., assignor to Sasgen Derrick Co., Chicago, Ill., a corporation of Illinois Application October 21, 1946, Serial N o. 704,684

1 Claim. 1

This invention relates to a scaffold hoist and winch, and is an improvement over the construction shown in my pending application Serial No. 670,945, l'lled May 20, 1946, now Patent No. 2,424,910, granted July 29, 1947, for Safety scaffold.

An object of this invention is to provide an improved winch construction wherein the winding drum can be manually rotated to either wind or unwind the cable therefrom, and the crank handle can be automatically locked against turning so that the crank handle will not be pulled or jerked from the hand by undue pressure thereon.

Another object of this invention is to provide an improved safety lock for a winch embodying automatically operable clutch means for the driving pinion or gear so as to positively lock the pinion to a ratchet member.

A further object of this invention is to provide a safety winch for a scaffold wherein the Winding drum is automatically locked against unwnding and can only be unwound by proportionate rotation of the crank handle, excessive rotation of the drum causing the looking means to become immediately effective so as to thereby relieve the crank handle pressure from the drum.

A further object of this invention is to provide an improved clutch and clutch operator associated with the crank handle so that the crank handle will serve as a brake during the unwinding operation.

With the above and other objects in view, my invention consists in the arrangement, combination and details of construction disclosed in the drawings and specication, and then more particularly pointed out in the appended claim.

In the drawings,

Figure 1 is a detail side elevation, partly in vertical section of a scaffold winch constructed according to an embodiment of this invention, showing the clutch in released position,

Figure 2 is a fragmentary sectional View taken substantially on the line 2-2 of Figure 1, with the clutch in locked or clutching position,

Figure 3 is a sectional view taken on the line 3-3 of Figure 2.

Figure 4 is an end elevation of one of the cam members for actuating the clutch.

Referring to the drawing, the numeral II) designates generally a frame structure which includes side members II and I2 secured together by fastening means I3 and held in spaced apart relation by means of spacer sleeves I4. The frame asi- 187) Ill has rotatably mounted therein a winding drum I5 which is carried by a shaft I6 journaled between the sides II and I2 of the frame Ill. The drum I5 also includes a large spur gear I1 which is fixed relative to the drum and may form one end wall of the winding drum.

The frame I0 als@ has journaled thereacross a driving shaft I8 which at one end thereof, has pivotally secured thereto a crank handle I9. As shown in Figure l, the inner end of the shaft I8 is formed with a flattened portion 20 and the adjacent end of the crank handle I9 is bifurcated, as indicated at 2l and pivotally mounted on a pivot member 22 extending through the bifurcations and the flattened portion 20.

The shaft I8 has fixed relative thereto a relatively large diameter clutch plate 23. A ratchet member generally designated as 24 is rotatably mounted o-n the shaft I8 in confronting position respective to the clutch plate, and in the present instance, the body 25 of the ratchet member 24 constitutes an intermediate clutch plate. The ratchet 24 is adapted to be held against rotation by means of a pivoted dog 2B which is provided at its upper end with a boss or bearing 21 loosely engaging the uppermost of the fastening members 23. The dog 26 gravitatingly engages the teeth of the ratchet 2E and is adapted to be manually swung to a reversed position when in released position.

The spur gear I'I also has engaged therewith a gravity actuated dog 23 also pivotally carried by the uppermost of the fastening members I3. The dog 28 engages the gear I1 on the side opposite from the engagement of the dog 26 with the ratchet 24. A driving pinion or gear 2-9 is loosely mounted on the shaft I8 and has formed at one end thereof a clutch plate 30 disposed in confronting relation to the clutch plate 25 of the ratchet 24. The pinion 29, at the opposite or inner end thereof has formed thereon cam members 3I. The cam members 3I are disposed in confronting relation to complementary cam members 32 which are formed on the inner end of a sleeve `33 which is fixed by means of a pin 34 on the shaft I8. The cam member 3I is constantly urged to rotate the pinion 29 toward clutching position by means of a spiral spring 34 which is fixed at one end as at 35, to the cam 3| and is fixed :at the other end, as at 36, to the sleeve 33. The effect o-f the spring 34 is to partially rotate the driving gear or pinion 29 when the shaft I8 is held stationary so that the pinion 29 `will be moved endwise or outwardly to cause the clutch plate 30 to bear against the intermediate clutch plate 25 and t0 other and as ratchet 24 is held against;rotation.by,y the dog 26, the drum l5 is therebyl'ocked against rotation.

The force necessary to holdthashaftli!.again stv rotation is only ya slight force so that the unwinding pressure or pull on the drum I5 will notv tend.r

to pull the crank I9 out ot the hands of the operatar.'v

Vl 9 be-.rotated proportionately therewith in the un,- wi-nding direction. Thisvunwinding direction isa counter-clockwise direction and the speed-A ofrotation of thecrank i9: will determine the. speed The effect of this is to cause the pinion 29# to move endwise to the right, bringing thefclutch plates 25 and'23 into tight engagement with eachv In. order to. permitlthe drum, tt'nto unwind; the-cable therefrom, it'. is necessary thatthecranli;

of unwinding. ofthe drum l5. In thismanner the clutch means hereinbefor-e describedcwill act;-

withthe` crank. laas. a releasablebrake for releasably. holding the drum l5 againstrotationl inl an unwindingdirection.

In the event the handle I9 is left free@ andL a.:

pulling strain is placed on the. drum l5, causingv thecable to. unwind therefrom, this pullingstrain` will tend to rotate thepinion ZBLbutas thispinion. is lunder' the torsional tension` of spring 34?; the pinion. 29 vwill be caused to. be moved relative to thek sleeve 33 andthecam members: 32;so.that theA winding or lowering of. thescaiold inasmuch as.

thev clutching means hereinbefore described, Will*v be. automatically. moved to clutching or locking.

position with respect. to the. winding drum since;

the crank handle is held against rotation by' the operator or is even left free. This. winch` will provide. a factor of safety for theI workmen.k on

the scaffold `so .that the workmen` wilt noty have,v

4 to release or lock any part of the winch Iwhen winding or unwinding the drum.

What I claim is:

A safety means fo'r the winding drum of a winch comprising front and rear plates, spacing means adapted to hold said plates in spaced apart relation, a winding drum journaled between said front and real? plates,V a,spur gear forming the front end wall of said winding drum, a drive shaft journaled between said plates above said drum and extending through the front plate, a, crank on the eX- tending portion of said shaft, an outer clutch plate fixed to said shaft, ya driving gear loose on said sha-ft and in operative engagement lwith said v'spur gear; an innerclutch plate iixed to said driv- .ing gear, an intermediate clutch plate between plate against rotation in the drum unwindingl direction, spiral cam means carried bythe inner end of said driving gear, a. sleeve fixed on said-- shaft, spiral camV means Ycarried bysaid 'sleeve confronting said first spiral cam means, a con tractile clutch operating spring, means securing oneV end oi` ^said`- spring-to the outer side of saidfirst spiralcam means,v means securing the otherv end of saidspring-to the outer side of said sleeve;l

said spring constantly-urgingY said first camvmeans to rotate to clutchingposition, anda seconddog pivotally carried bysaid spacing means adapted toY engage said spur gear lwhereby an additional` safety loc-lis provided:`

JESSE'M. BENSON.

REFERENCESl CITED:-

The following references are ofjrecordj in the nie of this. patent.:y

UNHED STA-.TES PATEN'I-.Si'

Number- Name i Date- 658,990-A Kincaid Oct; 2, 1900. 771,850y Mayerl Nov'- 15, 1904 1,412,013 Cummingsl Apr. 4,4922; 1,444,737 Fraley Feb. 6, 1923k 1,551,072 Stine Aug/25; 1925A 2,177,362' Eason Oct; 24,1939 2,280,180 Van C-leave Apr. 21,1942-L 2 ;.42,4,9`10 Benson Jul-y-29,;1947

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