US2554990A - Ratchet mechanism - Google Patents

Description

May 29, 1951 L. E. KILNESS 4, 9

RATCHET MECHANISM Filed Nov. 18, 1949 2 Sheets-Sheet 1 I N VEN TOR.

y 29, 1951 4 E. KILNESS 2,554,990

RATCHET MECHANISM Filed Nov. 18, 1949 2 Sheets-Sheet 2 2O 25 as 27 29 2 17 18 1 Z 4 w Ii 4 2. 1' 1 I TH l4 J h 1 IN VEN TOR.

Patented May 29, 1951 UNITED STATES PATENT OFFICE j RATCHET MECHANISM Luther E. Kilness, Sioux Falls, S. Dak.

Application November 18, 1949, Serial No. 128,103

4 Claims.

This invention relates to ratchet mechanisms and has particular reference to ratchet wrenches.

The primary object of this invention is to provide 'aratchet mechanism of such high strength that the. ratchet head may be of a greatly reduced and compact size as compared to conventional Figure. 2 is a similar view on the line 2-2 of 5 Figure5."

Figure.3 is a top view of the wrench.

Figure 4 is a sectional View taken on the line 4-4 of'Figure 5.

Figure 5 is a vertical section taken on the line 5-5-5; of Figure 4.

The wrench has a driving member comprising a handle l integrally formed with a wrench headIlII i. The Wrench head II has a cylindrical opening to receive the head portion of a workturning. member I2. A retaining ring I3 is pressed into afshouldered recess on the lower side of the head li'l and secures the turning member I2 in the wrench head II. The turning member is aligned in the head II by the ring l3 and by the peripheral portion of the turning member bearing against ratchet teeth M in the head II.

The {turning member I2 has two opposite concaveerecesses having thrust-bearing ends that are curved towards radial lines on the turning member I2. Pawls I6 are carried in the recesses I5. he pawls are shaped with a long curved side having ratchet teeth that conform to the toothed portion of the head II and with two shorter opposing sides that conform to the ends of the recesses I5 when the pawls are in full engagement with the teeth in the head I I. The pawls I6 are smaller than the recesses l5 and have a shorter length to permit withdrawal of the pawls from the ratchet teeth I4. Every tooth on each pawl is used to drive the turning member I2 for both ratcheting directions. Each pawl engages a section of teeth in the head II having about 20% of the total number of teeth I4.

The force transmitted to each pawl by the turning member I2 is directed perpendicularly to the radially curved ends of each recess. The moment arm of the force extends well into the outside half of the turning member I2 and may be designed to approach the periphery of the turning member l2. The components of the force diverge outwards on both sides to pass to the individual pawl teeth. The curvature "of the teeth over the large section of teeth used. enables the diverging components to approachjthe teeth at approximately right angles to the sides of the teeth. The teeth are therefore under compression on the side the force components are directed to and are capable of withstanding heavystresses efliciently.

The combination of the large number of ratchet teeth effectively used and the large moment arms give the mechanism an exceptionally high torque capacity. The high torque capacity permits a considerable reduction in the size of the head members and enables the ratchet to be conveniently used in places Where conventional ratchets would be too large.

The ratcheting motion of the pawls l6 is controlled by a reversing disc II, control plates l8, and springs I9. Pins are pressed ihto small holes in the tops of the pawls and extend past slots 2| in the reversing disc H, where they are terminated by rectangular projections that fit into rectangular holes in the controlplates I8.

During the ratcheting action, one end'of each spring I9 is held out of contact with thecontrol plates l8 by a spring guide 22 whilethe other end of each spring I9 is free to press against a control plate [8, as shown in Figurejld. The spring guide 22 maintains the positionishown in Figure 4 relative to the spring ends until the ratchet motion is reversed by the manual control.

The ratcheting action is as follows. For illustrative purposes, the action is described for the direction which drives the work clockwise.

The handle is turned counter-clockwise to obtain a new hold. This permits the springs l9, which act on the pawls l6 through the control plates lit, to move pawl ends [6a away from the ratchet teeth I4. At the same time, the pawls l6 are pivoted by the pins 20 as the pins contact the inner portion of the slots 2i in the reversing disc H. The spring pressure acting on the pawls tends to rotate the pawls about the pivots provided by the inner sides of the slots and urges pawl ends I6b against the ratchet teeth 14.

As the handle movement is continued in a counterclockwise direction for a new hold, the ratchet teeth I exert a frictional drag on the ,pawl ends I619. The frictional force between the pawl ends I61) and the ratchet teeth It causes the pawls to follow the ratchet teeth I4 until the pawl pins are brought against the sides of the 3 slots 2|. The pawls are thereby prevented from following the ratchet teeth further, and continued back movement of the handle causes the pawl ends-[6b to engage successive series of teeth of the ratchet teeth I4. I

As the handle is turned in a clockwise direction to drive the work, the pawl ends lGb are still releasably held against the ratchet teeth Ill. The pawl ends Ilia are now forced against the ratchet teeth by the concave surfaces of recesses iii to bring all of the pawl teeth into locking engagement with the ratchet teeth M.

The ratcheting direction is dependent on the angular position of the reversing disc IT and spring guide 22 relative to the turning member l2. Spherical detents 23 hold the reversing disc in either of two positions, depending on the ratcheting direction. The two positions of the reversing disc align the slots 2| so that the pins 20 may have pivotal supports in both ratcheting directions. Figure 2 shows the position of the reversing disc for driving the work in a clockwise direction. For turning the work in a counterclockwise direction, the slots 2! on the reversing disc must be positioned toward the other side of each recess [5. r

-The spring guide 22 has a square extension fitted to the reversing disc IT to change the angular position or the spring guide for the two ratchetin directions. The ends of the spring guide intercept the ends of the springs l9, which are fixed to the turning member I? by extensions from the center of each spring l9 that enter grooves 26 on the periphery of the turning member. Relative motion between the spring guide 22 and the springs i9 causes one end of each spring [9 to be withdrawn from the control plate while the other end is free to actuate the control plate. Figure 4 shows the position of the spring guide for driving the work in a clockwise direction. For the counterclockwise driving direction, the spring guide intercepts the spring ends which are shown in contact with the control plates l8 in Figure 4.

-The spherical detents 23 are contained in two diametrically spaced holes in the turning member i2. Helical springs 2% force the detents 23 against the reversing disc ii. A projection 25 extending from the turning head 92 holds the "reversing disc and spring guide to the turning member i2 against the pressure of the detents 23. The spherical detents 23 are urged against two smaller diameter holes in the reversing disc which are diametrically offset so that onl one detent isoperable at a time. The reversing disc is held in position by either detent to give two angular positions corresponding to the two ratcheting directions.

A push button 2? gives manual control of the ratchetin direction. Pressure on the push buttoniorces down a push rod 28 against a spring 29. The end of the push rod is secured to a wedge 30. The downward movement of the push button '21 brings the wedge 36 against two balls 3|, which are in a hole joining the recesses I53. The wedge 39 forces the balls apart and against the pawls and locks the pawls with the ratchet teeth l4. With the push button in the normally up position, as shown in Figure 5, the wedge 30 is witl'idrawn from the bails 3i and permits them to have freedom of movement in the hole joining the recesses !5. The pawl action is then unaffected by any contact that the loosely confined balls 3| may have with the pawls. In operation, the ratcheting direction is sereleased.

lected by depressing the push button 21 and rotating the handle through a small arc in the direction that the work is to be driven. Depressing the push button locks the pawls with the wrench head II, and the subsequent rotation of the handle causes the pawls to be moved to the other end of the recesses l5. The reversing disc is shifted by the pawl pins 20 to the second operative position. The spring-pressed balls or detents 23 are partly entered in holes in the reversing disc I! and have a holding effect on the reversing disc that is sufficient to maintain the position of the reversing disc once reversal is effected. During reversal of the ratchet mechanism, the normal holding force acting on the reversing disc is overcome by the movement of the pawls to the opposite ends of the recesses l5. The movement of the pawls brings the pawl pins 26 against the slots 2| in the reversing disc and causes the reversing disc to be rotated against the holding force of one detent 23 to a new angular position where the second detent 23 may'enter one of the offset holes in the reversing disc. With the pawls now moved to the other ends of the recesses I5 and the reversing disc held in position by the second detent 23, the push button ma be The driving action of the ratchet mechanism is now in the same directionasthe rotation of the handle while the push button was depressed.

While one form of the invention has been described, the invention is not limited to theparticular structure shown except as specified in the following claims, in which I claim:

1. In a ratchet mechanism, the combination of a driving member and a work-turning member, one of said members having a cylindrical opening with inwardly extending ratchet teethv and the other having a head portion rotatably mounted in said opening, a reversible pawl carried in a concave recess on the side of the head portion, the ends of the recess being curved towardsradial lines on the head portion, said pawl having two short sides conforming to the thrust-bearing ends of the recess and a long curved side joining the short sides made with a series of ratchet teeth, the size or" the pawl being smaller than the recess to permit withdrawal of the pawl from engagement with the-teeth in the cylindrical opening, means for bringing every tooth on the pawl into reversible and coacting engagement so that the combination of the simultaneous engagement of a large section of teeth in the cylindrical opening and the radially curved ends of the recess may have a compressional force action on the. sides of the pawl teeth, the compression components of each tooth adding to a large resultant force having a large moment arm in the outside half of the head portion for a maximum torque effect, and means for reversing the ratcheting direction.

2. In a ratchet mechanism, the combination of a driving member having a cylindrical opening with inwardly extending teeth, a work-turning member rotatably mounted in the cylindrical opening, said turning member having a recess on one side, a reversible pawl carried in the recess, said pawl having two short opposing sides conforming to the ends of the recess and a long curved side joining the opposing sides made with a series of ratchet teeth conforming to the'teeth in the cylindrical opening, the len th of the pawl being shorter thanthe distance across the ends of the recess to permit withdrawal of the pawl from engagement with the teeth in the cylindrical opening, means for disengaging'one pawl end while the other pawl end is releasabl pressed against the teeth in the cylindrical openingfas the driving member isturned back for a' 'new hold and for bringing allof the pawl teethin'to concurrent engagement with the ratchet teeth i'n the cylindrical opening during the positive stroke of the driving member, and means for reversing the ratcheting direction. v

3. In a ratchet mechanism, the combination of a driving member hayinga cylindrical opening with inwardly extending teeth, a work-turning member rotatably mounted in the cylindrical opening, said turning' mefmber having al recess containing a toothed paw of smaller si'zef'tlian the recess to permit 'witfhdrawal of the pawl from the teeth in thecylindrical opening, and means for turning the p'avfvl as the driving member is brought back for a new hold so that the teeth on one end of thepawl may be withdrawn from the teeth in the cylindrical opening while the teeth on the other end of the pawl are releasably pressed against the teeth in thelI'cyIindrical opening, said means cooperating with" the recess for bringing the" teeth on both pa} ends into concurrent engagement with the iratehet teeth in the cylindrical opening during the positive stroke of the driving member. M

4. In a ratchet mechanism, the combination of a driving member having a cylindrical opening with inwardly extending teeth, a work turning member rotatably mounted in the cylindrical opening, said turning member having a recess on one side, a reversible pawl carried in the recess, said pawl having two similar opposing sides conforming to the ends of the recess and a long curved side with ratchet teeth conforming to the teeth in the cylindrical opening, means for pivoting the pawl at either of t wo positions in the recess for the two ratchetingdirections, means for turning the pawl as the driving member is brought back for a new hold so; that one pawl end may be withdrawn from the teeth in the cylindrical opening while the other end of the pawl is releasably pressed against the teeth in the cylindrical opening, said turning means cooperating with the recess for bringing all of the pawl teeth into concurrent engagement with the ratchet teeth in the cylindricali'opiening during the positive stroke of the driving'member, and means for reversing the ratcheting direction.

- LUTHER E. KILNESS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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