US2684833A - Safety winch - Google Patents

Description

y 27, 1954 J. M. BENSON 2,684,833 SAFETY'WINCH Filed Feb. 18, 1952 2 Sheets-Sheet 1 III II III INVENTOR JsseMfienso n mg-4M ATTORNEYS J. M. BENSON SAFETY WINCH July 27, 1954 2 Sheets-Sheet 2 Filed Feb. 18, 1952 INVENTOR 8 5 s 6 M59 ATTORNEYS Patented July 27, 1954 UNITED STATES PATENT OFFICE SAFETY WINCH Jesse M. Benson, Concord, Tenn. Application February 18, 1952, Serial N 0. 272,039

4 Claims.

This invention relates to safety winches and winding drums.

In a scaffold winch there drum for the suspension cable with a ratchet means to prevent unwinding of the cable. It is an object of this invention to provide in a is provided a winding Another object of this invention is to provide a safety lock for a winding drum which may be the winding drum should rotate at an excessive speed, the latter is immediately locked against further unwinding.

A further object of this invention is to provide a safety lock of this kind which is simple in con struction and positive in action.

With the above and other objects in view, my

invention.

Figure 2 is a fragmentary side elevation of the device.

Figure 3 is a fragmentary vertical section through the device.

Figure 4 is a fragmentary sectional on the line 4-4 of Figure 3.

Figure 5 is a sectional view taken on the line 55 of Figure 3.

Figure 6 is a sectional view taken on the line 6-6 of Figure 3.

Referring to the drawings, the numeral I0 designates generally a frame structure which is formed of parallel side members II and I2 connected together at their upper ends by a connecting bar I3. The lower ends of the side bars II and I2 are secured together by means of a hanger support I4, which is fixed between the side bars II and I2 by means of bolts I5. A platform hanger l6 of conventional construction is suspended from the support I4.

A cable winding drum generally designated as view taken I! is rotatably disposed in the frame In and includes a relatively large spur gear I8, which is fixed to a tubular sleeve I9. A side wall 20 is secured to the sleeve I9 oppositely from the gear I 8. A stationary shaft 2| having reduced threaded opposite ends 22 is disposed between the frame members II and I2, and nuts 23 are threaded on the ends 22 so as to hold the frame bars II and I2 in spaced parallel relation and also hold the shaft 2| against rotation.

A pawl 24 is rockably carried by the side frame bar II and engages the spur gear I8, which also constitutes a ratchet. The pawl 24 is provided with an upwardly projecting handle 25 disposed on the forward edge of the frame member I3, and the latter limits the rocking movement of the pawl 24 to a released position.

by a pivot member 32, which is fixed to and pro jects inwardly from frame bar I2. The pawl 3| is a safety pawl, and the latter is normally held against locking engagement with ratchet 30 by means of a cam 33, which is carried by a lever or arm 34 integral with pawl 3|.

The cam 33 with lever 34 ment with the ratchet.

The cable 29 is extended upwardly to a suitable supporting structure and is guided above the J frame Ill by means of a pulley 35 carried by a pair of ears 36 which are fixed to the upper end of an upright guide support 31. The guide support 31 is fixed to the upper frame bar I3.

I do not mean to confine myself to the exact details of construction herein disclosed, but claim all variations falling within the purview of the appended claims.

What is claimed:

1. A winch comprising a frame, a winding drum rotatable in said frame, a driven gear fixed relative to said drum, a drive shaft rotatable in said frame, a driving gear fixed to said shaft and. meshing with said driven gear, a ratchet fixed to said drive shaft, a pawl rockably carried by said frame engaging said ratchet, and a pawl operator fixed to said pawl and extending angularly therefrom, said operator comprising an arm integral with said pawl and extending angularly therefrom, and a cam carried by said arm slidingly engaging the teeth of said ratchet, said operator normally riding over the teeth of said ratchet and the weight of said operator gravitatingly holding said pawl against locking engagement with said ratchet, said operator upon reverse rotation of said ratchet at a speed above normal effecting rocking of said pawl to locking engagement with said ratchet.

2. A winch comprising a frame, a winding drum rotatable in said frame, a driven gear fixed relative to said drum, a drive shaft rotatable in said frame, a driving gear fixed to said shaft and meshing with said driven gear, a ratchet fixed to said drive shaft, a pawl rockably carried by said frame engaging said ratchet, and a pawl operator fixed to said pawl and extending angularly therefrom, said operator comprising an arm integral with said pawl and extending angularly therefrom, and a cam carried by said arm slidingly engaging the teeth of said ratchet, said operator normally riding over the teeth of said ratchet and the weight of said operator gravitatingly holding said pawl against locking engagement with said ratchet, said operator upon reverse .ro tation of said ratchet at a speed above normal effecting rocking of said awl to locking engagement with said ratchet, and a locking pawl carried by said frame engageable with the teeth of said driven gear.

3. A winch comprising a frame, a winding drum rotatably mounted in said frame, a driven gear which also constitutes a ratchet, fixed relative to said drum, a drive shaft rotatably mounted in said frame, a driving gear fixed to said drive shaft and meshing with said driven gear, a pawl rockably mounted on said frame above said driving gear and having an operating arm for lifting said pawl, said pawl having a portion normally engaging the teeth of said driven gear and adapted to ratchet thereover, a ratchet wheel fixed to said drive shaft spacedly from said driving gear, and a safety pawl pivotally mounted intermediate its ends on said frame adjacent said ratchet wheel, said safety pawl having a weighted end portion normally lifting said pawl out of engagement with said ratchet wheel and resting on said wheel, said safety pawl having another portion to engage said ratchet wheel upon reverse rotation of said ratchet wheel at high speed to effect locking engagement with said ratchet wheel to thereby prevent unwinding of a cable from said drum.

4. In a winch, a frame, a shaft journaled in said frame, a winding drum mounted on said shaft for rotation in both winding and unwinding directions, an operating member having a positive motion-transmitting connection with said winding drum for imparting winding and unwinding movements thereto, a ratchet wheel positioned for rotation with said drum, a pawl pivoted near its midpoint on said frame and above and in the plane of said ratchet wheel, said pawl having at one end a ratchet-engageable detent and at its other end a weight which normally rests upon the outer edge of the ratchet wheel and holds the detent out of locking engagement with the ratchet wheel, the pawl being moved about its pivot by action of the ratchet wheel on the weighted end of the pawl, upon rotation of the drum in an unwinding direction at a speed in excess of a predetermined speed, to a position in which the detent is in locking engagement with the ratchet wheel.

References Cited in the file of this patent UNITED STATES PATENTS

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