US3393780A - Reversible ratchet - Google Patents

Description

July 23, 1968 L E. KlLNl-:ss 3,393,780

REVERSIBLE RATCHET Filed Jan. 26, 1967 2 Sheets-Sheet 1 July 23, 1968 l.. E. KlLNr-:ss

REVERSIBLE RATCHET 2 Sheets-Sheet 2 Filed Jan. 26, 1967 LUTHER E. K/LNESS United States Patent O 3,393,780 REVERSIBLE RATCHET Luther E. Kilness, 211 E. Philadelphia St., Rapid City, S. Dak. 57701 Continuation-impart of application Ser. No. 377,029, .lune 22, 1964. This application Jan. 26, 1967, Ser. No. 617,760

Claims. (Cl. 192-43.2)

ABSTRACT OF THE DISCLOSURE The ratchet mechanism here disclosed utilizes a wedgeaction pawl. Detent means act on the pawl for controlling the pawl. One form of the detent means includes a springpressed ball acting on an apex of the pawl. A reversed form of the detent means has a spring attached to the pawl acting on detent surfaces in the pawl-carrying body. An element which acts on the pawl to shift the pawl may act as a guide for orienting the pawl relative to opposing ratchet teeth on a tooth-carrying body to assist in proper engagement of the pawl teeth with the opposing ratchet teeth. A manual control which is coaxial with the toothcarrying body is disclosed for displacing the element acting on the pawl to shift the pawl.

Cross-references, to related applications This application is a continuation-in-part of my prior application Ser. No. 377,029, filed June 22, 1964, and now abandoned, which is a continuation-in-part of my application Ser. No. 76,341, tiled Dec. 16, 1960, now abandoned.

Background ofthe invention The invention relates to clutches or ratchet mechanisms in which the engaging element is a wedging pawl. The invention has particular application to the ratchet mechanisms used in hand tools, such as ratchet wrenches.

Various control systems have been used for controlling wedge-action pawls. Examples of some of these control systems can be seen in my United States Patents No. 2,554,990, issued May 29, 1951, No. 2,981,389, issued Apr. 25, 1961, No. 3,044,591, issued July 17, 1962, No. 3,078,973, issued Feb. 26, 1963, No. 3,265,171, issued Aug. 9, 1966, and No. 3,269,496, issued Aug. 30, 1966.

The control system which would be used in any application employing a wedge-action pawl would depend on the design requirements for t-he ratchet mechanism. As applied to ratchet wrenches, particularly where the pawl is positioned in a recess at the junction of the handle and head members, it is advantageous that the pawl controls be -very compact. This is becoming increasingly important, since the direction of ratchet wrench design is to make the wrench heads as small as possible in order that the ratchet wrenches may be used in places where space is limited. It is also desirable that the pawl control system have few parts, which are of simple and rugged construction for longer ratchet life.

Summary of the invention The invention is a control system for directing wedgeaction pawls. One feature of the invention is detent means which in the simplest form consists of a spring-pressed ball engaging an apex formed on the back of the pawl. This feature is advantageous where the pawl is positioned at the junction of a wrench head and handle, since it takes very little space, and the small bore containing the spring and ball does not weaken the handle. While this feature may be used in combination with other pawl control elements, it can also be used as the sole ICC element engaging the pawl during the back ratcheting action. In this case, the correct placement and angle of the apex on the pawl relative to the pawl teeth are important to ensure ratcheting action.

Another feature of the invention is a guide for orienting the pawl during the back ratcheting action of the pawl. This feature enable the pawl to be properly positioned during the important re-engagement part of the ratcheting cycle when all of the pawl teeth are brought into full engagement for driving. The proper positioning of the pawl prevents misalignment of the pawl teeth with the opposing ratchet teeth as may occur where a large number of teeth are formed on the pawl. The arrangement of the guide or shift element also permits convenient placement of the manual control ahead of the pawl, which results in a stronger construction for the embodiments having the pawl carried by the handle since the handle is not weakened by additional bores for the manual control elements behind the pawl recess.

Brief description of the drawing FIGURE 1 is a vertical section of a ratchet wrench selected to illustrate the invention.

FIGURE 2 is a partial horizontal section of the ratchet Wrench shown in FIGURE 1.

FIGURE 3 is a horizontal section of a modiiication of the ratchet wrench shown in FIGURES 1 and 2.

FIGURE 4 is a modification of the invention showing a linear-action ratchet mechanism.

FIGURE 5 is a fragmentary diagrammatic View of a mechanism similar to those in FIGURES 1, 2, and 3.

FIGURE 6 is a fragmentary Iview of a ratchet mechanism employing a spring-pressed ball element but having the pawl carried by the rotatable member instead of the handle.

Description ofthe preferred embodiments The ratchet wrench shown in FIGURES 1 and 2 has a body member 10 with a head 11 formed at one end. A rotatable member 12 is journaled in a circular opening 13 in the head for relative motion with respect to the body member 10. The rotatable member has a series of radially extending ratchet teeth 14 formed along a cylindrical portion. A square projection 15 is formed on one end of the rotatable member for receiving sockets. A spring-pressed ball 16 on the projection retains the sockets. A shift cam 17 coaxially positioned with respect to the rotatable member seals the top of the wrench head. A bottom seal 18 completes the closure 0f the internal ratcheting parts. The bottom seal extends beneath a pawl recess 19 and follows the outline of the pawl recess. A split-type retaining ring 20 fits in a groove in the head for maintaining the ybottom seal in assembly. The ends of the retaining ring are accessible at the back of the head 11 and may be compressed to remove the retaining ring.

The pawl recess 19 is positioned opposite to the ratchet teeth 14 and intercepts a portion of the ratchet teeth. The pawl recess has two sides at the ends of the recess forming bearing surfaces inclined or converging toward each other in a direction away from the ratchet teeth. A pawl 21 is carried in the pawl recess. The pawl has an arcuate side having a series of teeth 22 adapted to the ratchet teeth 14. All of the pawl teeth are 'used for reversible engagement with the ratchet teeth 14 and are brought into full concurrent driving engagement with the ratchet teeth 14 for the forward or driving stroke of the mechanism, which is that part of the ratcheting cycle Where the mechanism is driving or turning the work. In concurrent driving engagement, all of the pawl teeth are simultaneously in register with or engaged with the ratchet teeth for driving. The arcuate side of the pawl is shorter than the dimension of the pawl recess along the envelope of the ratchet teeth 14, and the other dimensions of the pawl are smaller than comparable recess dimensions to permit circumferential or lateral and radial freedom of movement for the pawl. The pawl has sides joining the arcuate side which are generally inclined or convergent toward each other in a direction away from the arcuate side. The converging sides of the pawl form bearing surfaces matching the converging sides of the pawl recess for transmitting the thrust of the pawl to the body mem- `ber for the two driving directions.

The present invention comprises control means which includes elements acting between the pawl and the body member 10 that cooperate to urge the pawl into ratcheting engagement with opposing ratchet teeth. The control means also includes shift means which comprises elements that cooperate to shift the pawl from one side of the pawl recess to the other for reversing the ratchet mechanism. The control means includes pawl controls having detent means which cooperate Iwith resilientlyacting means for yieldingly urging the pawl toward either selected bearing surface of the pawl recess. The detent and resiliently-acting means control system provides an efiicient means for controlling a wide-arc pawl of the wedging type and operates with small lateral movement of the pawl, which is particularly desirable for mechanisms having this type of pawl positioned on the handle member. In addition, the small space requirements of this control system are important since modern ratchet wrench design requires increasingly smaller wrench heads.

In the embodiment shown in FIGURES l and 2 the resiliently-acting means comprises a ball 23. Resilient support for the ball is obtained from a spring 24 contained in a bore 25 in the body member 10. The ball engages two detent surfaces on the sides of the V-shaped apex of the pawl formed by the intersection of the straight surfaces ofthe pawl. The ball 23 engages one side of the apex lwith the pawl positioned toward one end of the recess 19 or toward one bearing surface of the recess and engages the other side of the apex with the pawl positioned toward the other end of the recess or toward the other bearing surface of the recess. If the angle of the apex of the pawl is approximately as sharp as shown in FIGURE 2, the ball will exert a force on the pawl tending to keep it against a selected bearing surface of the pawl recess and in contact with the ratchet teeth 14 and causing the pawl to slide over successive series of the ratchet teeth 14 during the back stroke.

A shift plate 26 is employed to shift the pawl from one bearing surface of the recess 19 to the other. The shift plate is positioned above the rotatable member 12 on a concentric hub 27 on the rotatable member. An extension 28 on the shift plate is entered into a groove 29 on the pawl to connect the shift plate to the pawl. The shift cap 17 is angularly attached to and positions the shift plate 26 by means of a pin 30 on the shift cap extending into and loosely fitted to a hole 31 in the shift plate. A friction spring 32 is mounted on the hub 27. The friction spring is secured to the shift cap by a projection 33 entered into a hole 34 in the shift cap. The friction spring exerts a frictional force on the hub for yieldingly urging the shift cap to maintain its angular position relative to the rotatable member 12 after the shift cap is manually shifted. The loose fit of the pin 30 projecting from the shift cap into the shift plate 26 affords limited sideways or lateral move. ment of the pawl independently of the shift cap when the pawl engages a successive series of the ratchet teeth 14 during the back stroke of the handle, while the shift cap is urged to subsequently maintain its angular position relative to the rotatable member 12 because of the friction spring.

A bar 35 on the shift cap 17 gives manual control of the direction of ratchet driving. With the mechanism adjusted as in FIGURES 1 and 2, the ratchet will drive in a clockwise direction. Shifting the bar in a clockwise direction will displace the shift plate 26 and force the pawl to the other bearing surface of the pawl recess against the resistance of the spring-pressed ball 23 which resists the lateral displacement of the detent surfaces on the pawl with respect to itself. The mechanism will then drive in a counterclockwise direction.

The modification of the invention shown in FIGURE 3 differs from the embodiment shown in FIGURES 1 and 2 chiefly in that a resiliently-'biased shift plate 36 is employed. The shift plate 36 has an extension 28 having a close sliding fit to a groove on top of the pawl. With a close fit to the pa-wl groove, the extension 2S serves as a guide means to guide or direct the pawl during the back stroke. Pins 37 and 38, extending from the shift cap, engage the ends of slots 39 and 40 in the shift plate for moving the shift plate when the shift cap is turned to either of two positions. The slots are of greater radial extent than the pins 37 and 38 to permit a slight rocking movement of the shift plate rfor aligning the pawl. The center lhole of the shift plate is larger than the hub 27 to permit the rocking or eccentric movement of the shift plate. A pin 41 secures a U-shaped spring 42 to the shift plate. The U-shaped spring alternately engages pins 37 and 38. As shown in FIGURE 3, one end of the U-shaped spring engages pin 37, while the other end of the U-shaped spring is free. With the U-shaped spring in the position shown in FIGURE 3, the shift plate is given a slight deflection downward as the back stroke is made, resulting in an eccentric positioning of the shift plate and causing the pawl, which is guided or directed by the extension 28 on the shift plate, to take an eccentric alignment or orientation relative to the cylindrical envelope of the ratchet teeth 14 during the back stroke. The eccentric alignment of the pawl given by the shift plate 36, which is independent of any alignment given the pawl by the bearing surfaces of the pawl recess, will cause the pawl teeth nearest the operative bearing surface of the pawl recess to go into engagement first with the ratchet teeth 14 prior to the driving portion of the ratcheting cycle or prior to full driving engagement of the pawl teeth with the ratchet teeth 14; and prevent a possible defective overlap or misalignment of the pawl teeth with the ratchet teeth 14 as might otherwise occur when the pawl teeth are forced into full engagement with the ratchet teeth 14 Ifor the driving stroke. The resilient biasing of the shift plate does not interfere with the concentric alignment of the pawl occurring under load conditions where the bearing surface of the recess forces the pawl to take an alignment as shown in FIGURE 3 and brings all of the pawl teeth into driving engagement with the ratchet teeth 14.

FIGURE 4 sho-ws a modification of the invention as applied to a linear ratchet mechanism. The mechanism has a body member 43 and a slidable member 44, which is positioned in a channel 45 in the body member. The slidable member has a series of ratchet teeth 46 formed along a straight line. The body member has a pawl recess 47 having inclined bearing surfaces. A pawl 48 is carried in the pawl recess. The pawl has a linear series of teeth 49 adapted to engagement with the ratchet teeth 46. A resiliently-acting means, consisting of a spring 50, is attached to the pawl. The spring 50 has a central section tightly titted or secured in a groove 51 in the pawl. The groove is formed in a raised portion 52 on top of the pawl. The spring 50 has V-shaped ends, which engage detent surfaces consisting of duplicates sets of V-shaped indentations 53 in a raised portion 54 of body member 43.

With the pawl in the position shown in FIGURE 4, the slidable member 44 can move down but is prevented from moving up by the wedging action of the pawl. As the slidable member is moved down, the V-shaped ends of spring 50 tend to ride up the inclined sides of the V-shaped indentations 53. The spring cannot move relative to groove 51 in the pawl, so that the spring ends will then be under compression and cause a restoring force tending to keep the pawl against the upper bearing surface of the pawl recess. During continued downward movement of the slidable member the pawl will engage successive series of the ratchet teeth 46. For controlling the ratchet direction a shift pin 55 is attached to the pawl. The shift pin passes through an oversized hole 56 in the body member 43, which permits freedom of movement for the shift pin. Moving the pawl with the shift pin causes the spring 50 to engage either of the two sets of V-shaped indentations 53 to maintain the pawl in position against a selected bearing surface of the pawl recess.

FIGURE 5 is a diagrammatic view of a ratchet mechanism such as shown in FIGURES l, 2, and 3 and illustrates how the pawl is kept in ratcheting engagement by the spring-pressed ball arrangement. The ratchet mechanism shown in FIGURE 5 has a rotatable member 57 provided with ratchet teeth 58. A body member 59 is fitted to the cylindrically disposed ratchet teeth 58. A toothed pawl 60 having inclined bearing surfaces is contained in a recess 61 in the body member which has corresponding bearing surfaces. A ball 62 is urged against the pawl by a spring 63 contained in a bore 64 in the body member. The ball exerts a force on the side of an apex on the pawl which is intermediate the bearing surfaces of the pawl and directed away from the toothed side of the pawl. This force acting on the pawl is perpendicular to the pawl Surface engaged by the ball and passes in a direction shown by the vector A. With the apex of the pawl formed and arranged as shown in FIGURE 5, the vector A is directed at an obtuse angle a to the extreme or end surface 81 of the pawl tooth adjacent to the selected operative bearing surface of the recess 61. The obtuse angle a should be larger than 90 degrees plus the angle of friction in order that the force exerted by the ball can overcome the frictional resistance between the ratchet teeth 58 and the end pawl teeth adjacent the operative bearing surface of the recess. The force acting on the pawl from the ball 62 will then cause the pawl to slide over successive series of the opposing ratchet teeth during the back or nondriving stroke of the body member 59. Under these conditions, the spring-pressed ball may act alone to hold the pawl in releasable ratcheting engagement with the ratchet teeth 58 during the back stroke.

FIGURE 6 shows a ratchet mechanism having a springpressed ball control element but having the pawl carried by the rotatable member. The embodiment shown in the fragmentary view of FIGURE 6 has a body member 65 provided with ratchet teeth 66. A rotatable member 67 is journaled in the body member. A pawl 68 is contained in a pawl recess 69 in the rotatable member. A ball 70 is urged against an apex on the pawl by a spring 71 positioned in a bore 72. The force acting on the pawl from the spring-pressed ball 70 is in a direction to urge the pawl toward either selected end of the pawl recess 69. Pawl springs 73 and 74 alternately engage pins 75 and 76 on opposing ends of the pawl. The pawl springs are held in position by pins 77 and 78 mounted on the rotatable member 67. A shift element 79 is positioned above the rotatable member and has an extension entered in a groove 80 on the pawl. The shift element may be comparable to shift plate 26 of FIGURE 2 or to shift plate 36 of FIGURE 3 where the guide or alignment function is preferred. The spring-pressed ball 70 may be used alone where shallow teeth are used in ratchets of the type shown in FIGURE 6, or the spring-pressed ball may advantageously be employed in conjunction with control elements such as pawl springs 73 and 74. The Pawl springs are spaced so that only one pawl spring engages a pawl pin 75 or 76 for a selected direction of ratchet driving. The forces acting on the pawl from the spring-pressed ball and the pawl springs are preferably adjusted to produce a resultant force of predominantly tangential direction. For reversing the direction of ratchet driving, the shift element 70 is displaced as described previously for shift plates 26 and 36 of FIGURES 2 and 3 respectively to move the pawl to either end of the pawl recess for engagement with converging bearing surfaces of the pawl recess.

The embodiments shown and described herein are illustrative of the invention and may be modied without departing from the invention as defined in the claims.

I claim:

1. In a ratchet mechanism having the combination of two members adapted to relative motion with respect to each other, one of said members having a series of ratchet teeth, the other of said members having a recess therein positioned opposite said ratchet teeth and intercepting part of said lratchet teeth, said recess having two bearing surfaces inclined toward each other in a direction away from said ratchet teeth, a pawl carried in said recess, said pawl having a side with a plurality of teeth adapted to concurrent driving engagement with said ratchet teeth, all of said teeth on the side of the pawl being used for driving in both directions, said pawl being smaller than the recess to permit lateral movement of said pawl in the recess, said pawl being adapted for engagement with the bearing surfaces of said recess for transmitting the thrust of the pawl to said other member for the two driving directions, and control means for urging the pawl into reversible ratcheting engagement with said ratchet teeth, wherein the improvement comprises one of said pawl and said other member having two detent surfaces and said control means comprising resiliently-acting means positioned on the other of said pawl and said other member, said resiliently-acting means being arranged to act yieldingly on either rselected detent surface during the back stroke of the ratchet mechanismfor yieldingly urging the pawl toward either selected bearing surface of said recess, said resiliently-acting means being adapted to engage one of said detent surfaces with the pawl positioned toward one bearing surface of the 4recess and engaging the other of `said detent surfaces with the pawl positioned toward the other bearing surface of said recess, said resiliently-acting means and said detent surfaces being arranged for lateral displacement with respect to each other on movement of said pawl from one bearing surface of the recess to the other, said resilientlyacting means and said detent surfaces being further arranged to act on each other for resisting lateral displacement of one to the other, said control means further comprising means engaging the pawl for moving the pawl against the resistance of said resiliently-acting means from one bearing surface of said recess to the other.

2. In a ratchet mechanism having the combination of two members adapted to relative motion with respect to each other, one of said members having a series of ratchet teeth, the other of said members having a recess therein positioned opposite said ratchet teeth and intercepting part of said ratchet teeth, said recess having opposing ends having bearing surfaces inclined toward each other in a direction away from said ratchet teeth, a pawl carried in the recess, said pawl having a lside with a plurality of teeth adapted to concurrent driving engagement with said ratchet teeth, all of said teeth on the side of the pawl being used for driving in both directions, said pawl being smaller than the recess to permit lateral movement of said pawl, Within said recess, said pawl having two bearing surfaces, the bearing surfaces of said pawl being adapted for engagement with the bearing surfaces of said recess for transmitting the thrust of the pawl to said other member for the two driving directions, and control means for urging the pawl into reversible ratcheting engagement with said ratchet teeth, wherein the improvement comprises said pawl having an apex intermediate said bearing surfaces of the pawl, the apex of the pawl being directed away from the side of the pawl having a plurality of teeth, and said control means including resiliently-acting means positioned on said other member adapted to selectively engage the pawl on either side of the apex of said pawl and arranged to provide a force acting in a direction urging the pawl toward either selected end of said recess, said resiliently-acting means being arranged to engage the pawl on one side of the apex with the pawl positioned toward one end of said recess and engaging the pawl on the other side of the apex with the pawl positioned toward the other end of said recess.

3. In a ratchet mechanism having the combination of two members adapted to relative motion with respect to each other, one of said members having a series of ratchet teeth, the other of said members having a recess therein positioned opposite said ratchet teeth and intercepting part of said ratchet teeth, said recess having two bearing surfaces inclined toward each other in a direction away from said ratchet teeth, a pawl carried in said recess, said pawl having a side with a plurality of teeth adapted to concurrent driving engagement with said ratchet teeth, all of said teeth on the side of the pawl being used for driving in both directions, said pawl being smaller than the recess to permit lateral movement of said pawl within said recess, said pawl being adapted for engagement with the bea-ring surfaces of said recess for transmitting the thrust of the pawl to said other member for the two driving directions, and control means for urging the pawl into reversible ratcheting engagement with said ratchet teeth, wherein the improvement comprises said pawl having two detent surfaces and said control means including resiliently-acting means cooperable with said detent surfaces for yieldably urging the pawl into engagement with either selected bearing surface of said recess, said resiliently-acting means being arranged to engage one of said detent surfaces with the pawl positioned toward one bearing surface of said recess and engaging the other of said detent surfaces with the pawl positioned toward the other bearing surface of said recess, said detent surfaces of the pawl being so formed and arranged that the force acting on the pawl from said resiliently-acting means is in a direction making an obtuse angle of suicient magnitude with the end surface of the pawl tooth adjacent to the bearing surface of said recess engaged by said pawl so that the resilientlyacting means urges the pawl to slide over said ratchet teeth and releasably engage a successive series of ratchet teeth during the back stroke of said other member.

4. In a ratchet mechanism having the combination of a body member with a circular opening, a rotatable member journaled in said opening, said rotatable member having a cylindrical portion provided with radially extending ratchet teeth, said body member having a recess open to said ratchet teeth, a pawl carried in the recess, said pawl being of smaller size than the recess to permit circumferential and radial movement in the recess, said pawl having an arcuate side provided with teeth adapted to concurrent and reversible engagement with said ratchet teeth, all of said teeth on the arcuate side of the pawl being used for driving in both directions, said recess having two sides forming bearing surfaces converging toward each other in a direction away from said ratchet teeth, said pawl having two converging sides corresponding to the bearing surfaces of the recess for transmitting the thrust of the pawl to the bearing surfaces of the recess for the two directions of driving, and control means for urging the pawl into reversible ratcheting engagement with said ratchet teeth, wherein the improvement comprises said control means including guide means engaging the pawl for controlling the alignment of the pawl relative to said ratchet teeth during the back stroke, said guide means being arranged to position said pawl prior to concurrent engagement 0f the pawl teeth with said ratchet teeth for driving so that the pawl teeth nearest the bearing surface of the recess receiving the thrust of the pawl enter into engagement with said ratchet teeth before the pawl teeth on the other end of the pawl engage said ratchet teeth, said guide means acting on the pawl to provide alignment independently of any alignment given the pawl by the bearing surface of the recess receiving the thrust of the pawl.

5. In a ratchet mechanism having the combination of a body member having a head with a circular opening, a rotatable member journaled in said circular opening, said rotatable member having a cylindrical portion provided with radially extending ratchet teeth, said body member having a recess open to said ratchet teeth, a pawl carried in said recess, said pawl being of smaller size than the recess to permit circumferential and radial movement in the recess, said pawl having an arcuate side provided with teeth adapted for concurrent and reversible engagement with said ratchet teeth, all of said teeth on the arcuate side of the pawl being used for driving in both directions, said recess having two sides forming bearing surfaces converging toward each other in a direction away from said ratchet teeth, said pawl having two converging sides corresponding to the bearing surfaces of the recess for transmitting the thrust of the pawl to the bearing surfaces of the recess for the two directions of driving, and control means for urging the pawl into reversible ratcheting engagement with said ratchet teeth, wherein the improvement comprises said control means including shift means positioned above said rotatable member, said shift means extending back for engagement with the pawl, said shift means being arranged to move said pawl from one bearing surface of said recess to the other on displacement of said shift means, said shift means including means adapted for manual control positioned on the head of said body member for displacement of said shift means.

References Cited UNITED STATES PATENTS 893,097 7/1908 Reams. 2,943,523 7/1960 Gray et al. l92-43.2 X 2,701,977 2/1955 Stone S31-63.2 2,957,377 10/1960 Hare 192--43.2 X 3,019,682 2/1962 Hare 192-43 X BENJAMIN W. WYCHE, III, Primary Examiner.

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