US3145594A

US3145594A - Ratchet wrench

Info

Publication number: US3145594A
Application number: US247935A
Authority: US
Inventors: Edwin E Peters
Original assignee: BONNEY FORGE AND TOOL WORKS
Current assignee: BONNEY FORGE AND TOOL WORKS
Priority date: 1962-12-28
Filing date: 1962-12-28
Publication date: 1964-08-25
Anticipated expiration: 1981-08-25

Description

Aug. 25, 1964 PETERS 3,145,594

RATCHET WRENCH Filed Dec. 28, 1962 FIG .4

INVENTOR 4e- Ed w|n E. Peters 4211 '8 ////A BY 28 F I G o 5 n ATTORNEY United States Patent 3,145,594 RATCHET WRENCH Edwin E. Peters, Schnecksville, Pan, assignor to Bouncy Forge dz Tool Works, Allentown, Pa, a corporation of Pennsylvania Filed Dec. 28, 1962, Ser. No. 247,935 8 Claims. (Cl. 8163) This invention relates generally to ratchet wrenches, and more particularly to a manually operable reversible ratchet wrench.

An object of the present invention is to provide a new and improved ratchet wrench which operates with a minimum amount of vibration and wear of its moving parts, resulting in a longer useful life and in eflicient, smooth operation of the wrench.

Another object of the invention is to provide a new and improved ratchet Wrench having a pawl mechanism capable of limited floating movement while being resiliently held in engagement with cooperating ratchet teeth.

Still another object of the invention is to provide a new and improved ratchet wrench having a pawl mechanism constructed and mounted to receive strains imparted from cooperating ratchet teeth as thrust strains rather than as shearing strains, thereby minimizing wear and any danger of shearing the teeth.

Yet another object of the invention is to provide a new and improved reversible ratchet wrench having a floating pawl mechanism resiliently connected to a reversing shift lever and positively movable with snap action when shifted.

A reversible ratchet wrench embodying the invention includes a handle secured to an operative head having an interior cavity, a cylindrical ratchet mounted rotatably within said cavity, said ratchet having a plurality of ratchet teeth on its periphery and being secured to a work piece engaging member projecting to the exterior of the head, a movable pawl having a plurality of teeth adapted to cooperate with the ratchet teeth to limit the movement of the ratchet to selectively reversible uni-directional rotary movement, a shift plate mounted movably adjacent to the pawl, and an exterior angularly movable shift lever connected to the shift plate for manual shifting thereof. A primary feature of the invention is an elongated spring extending between and engaging opposite sides of the shift plate and connecting said plate to a projection on the pawl, whereby the pawl is mounted for floating movement with its teeth constantly maintained in resilient engagement with the ratchet teeth, and the angular movement of the shift lever imparts corresponding shifting movement to the pawl through the spring connection therewith.

Other objects and the nature and advantages of the invention will be apparent from the following detailed description of a specific embodiment thereof, when considered in conjunction with the appended drawing, wherein:

FIG. 1 is a side elevation view of a ratchet wrench embodying the invention;

FIG. 2 is an enlarged top plan view of the operative head portion of the wrench with the ratchet and pawl mechanism therein shown in dotted lines in one operating position; a

FIG. 3 is a vertical sectional view taken along the line 3-3 of FIG. 2 with portions of the mechanism shown in elevation;

PEG. 4 is a horizontal sectional view taken along the line 4-4 of FIG. 3 with portions of the mechanism shown in full lines in one operating position and also FIG. 5 is a fragmentary horizontal sectional view taken along the line 55 of FIG. 3.

Referring in detail to the drawing, the illustrated ratchet wrench comprises a conventional handle portion 10 joined to an operative head portion 12. The handle portion 10 and the head portion 12 may be formed as a single integral unit, as shown in the drawing, or they may be separate parts securely connected together to form a rigid assembly.

The head portion 12 of the ratchet wrench is provided with a large cylindrical interior cavity 14, in which is freely rotatably mounted and snugly fitted a cylindrical ratchet 16 having a plurality of longitudinally extending ratchet teeth 18 on its circular periphery. The head portion 12 is also provided with a smaller cylindrical interior cavity 20 positioned adjacent to and intersecting an edge of the large cavity 14. Within the smaller cavity 25) there is mounted a movable pawl 22 which cooperates with the ratchet 16 to control the rotary movement of said ratchet.

The pawl 22 is preferably generally trapezoidal in shape along a horizontal cross-section thereof, as best shown in FIGS. 2 and 5. On one face of the pawl 22, being that face corresponding to the base side of its trapezoidal configuration, there are provided a plurality of teeth 24 near opposite ends of this face, which teeth 24 are adapted to mate with the ratchet teeth 18 when shifted into engagement therewith. On the opposite face of the pawl 22, corresponding to the apex of its trapezoidal configuration, the opposite edges thereof are provided with a pair of projections 26 terminating in arcuate surfaces 28 having a curvature corresponding to that of the wall of the small cylindrical cavity 20. The pair of projections 26 are separated by a recess 30 into which a fixed pin 32 projects, which pin serves as a fulcrum about which the pawl 22 is rocked during shifting of the operative direction of movement of the ratchet 16 of the wrench.

A shift lever 34 mounted on the exterior of the head portion 12 of the wrench is capable of easy manipulation by a flick of a thumb of the operator, while the wrench is held in one hand. A disc-shaped shift plate 36 mounted movably within the small cylindrical interior cavity 20 is joined to an integral boss 38 which projects outwardly through the head portion 12 of the wrench, and which boss 38 is secured to the shift lever 34. The shift plate 36 is provided with a central circular recess 40 having a socket 42 on one side thereof. A helical coiled spring 44 extends diametrically across the recess 40 and one end of the spring 44 projects into and is lodged within the socket 42, the opposite end of said spring being secured to the pawl 22. The upper end of the pawl 22 bears slid ably against the shift plate 36 on an annular face 43 exterior of the recess 40 therein, and the pawl 22 is provided with a bifurcated projection 46 extending into the recess 40 and straddling the coiled spring 44 in gripping engagement therewith at a point near the end which is adjacent to the pin 32 on which the pawl 22 is rockable as a fulcrum point, that is, opposite the end that is lodged in the socket 42. It is evident that shifting of the lever 34 by angular movement thereof from a flick of the op erators thumb, causes partial rotation of the shift plate 36 and consequent flexing movement of the coiled spring 44, as shown in FIG. 4, and due to the straddling engagement of the spring 44 by the bifurcated projection 46, the pawl 22 is thereby correspondingly angularly shifted from one to the other of the alternate operating positions in which it is illustrated in full lines and in dotted lines in FIG. 5.

Snap action in the shifting movement'of the pawl 22 is effected by an S-shaped spring 48 having flat sides, which spring 48 is mounted within the large cylindrical interior cavity 14. One end of the spring 48 is lodged within a notch 50 provided on the exterior of the shift plate 36 in a portion thereof projecting into the acvity 14, and the opposite end of the spring 48 is secured in a notch 52 provided in the side wall of the cavity 14 at a point approximately diametrically opposite the shift plate 36. As is best shown in FIG. 4, during shifting of the pawl 22 by partial rotation of the shift plate 36, the S-shaped spring 48 is moved alternately between the positions in which it is illustrated in full lines and in dotted lines in this view. In this shifting movement, the notch travels quickly with snap action between the extreme limits of its arcuate path of movement, which limits are defined by the two points of intersection of the interior cavities 14 and 29, thereby limiting the shifting movement of the pawl 22.

One end of the cylindrical ratchet 16 may bear lightly against one of the flat sides of the S-shaped spring 48 in sliding engagement therewith, thereby providing a snugly fitting mounting for the ratchet 16 while leaving it free to rotate within the cavity 14. A bearing surface for the opposite end of the ratchet 16 is provided by an annular shoulder 54 formed in the cavity 14, and this end of the ratchet 16 is provided with a cylindrical shoulder 56 to which is secured an exterior work piece engaging projection 58, of the type used in conventional socket wrenches.

A one-piece face plate 60 secured by staking it around its periphery to the head portion 12 of the wrench, retains the ratchet 16 and the pawl 22 properly positioned therein, and an O-ring 62 is mounted between the shoulder 56 and the face plate 60 to retain a lubricant in the interior while excluding dirt particles therefrom.

Due to the particular construction and mounting of the pawl 22, any strains imparted thereto by the ratchet 16 during operation of the wrench, are manifested as thrust strains rather than as shearing strains on the cooperating

teeth

18 and 24 of the ratchet 16 and the pawl 22, respectively. These teeth always engage each other fully in both of the two alternate operating positions of the pawl 22; or in other words, the cooperating teeth never are in partial or incomplete engagement, due to the positive action of the S-shaped spring 48. When the wrench is under load, strains transmitted from the ratchet 16 through the fully

engaged teeth

18 and 24 are further transmitted diagonally through the pawl 22, and the main component of the strains is parallel to the axis of the handle portion of the wrench.

It has been found that the angle of inclination of the pawl 22, with respect to the axis of the wrench handle portion 10 on either side thereof, should preferably be between about 25 and If this angle were substantially larger, there would be a danger of possibly shearing the

cooperating teeth

18 and 24. On the other hand, if the angle were substantially smaller, there would be a possibility of slippage between the teeth. Within the specified range of angles of inclination, the strains to which the pawl 22 may be subjected are thrust strains rather than objectionable shearing strains.

Summarizing the operation of the wrench, reversal of the direction of ratcheting movement of the work piece engaging projection 58 is accomplished by angular movement of the shift lever 34, merely by a flick of the operators thumb. This movement of the lever 34 causes partial rotation of the shift plate 36 through a corresponding angle, and due to the fact that one end of the spring 44 is lodged in the socket 4-2 at one side of the shift plate 36, this movement results in flexing of the spring 44 as shown in FIG. 4. The flexed spring 44- naturally tends to straighten itself out, and in doing so it shifts the pawl 22 angularly from one to the other of its alternate operating positions shown in full lines and in dotted lines in FIG. 5, such movement of the pawl 22 by the spring 44 being the result of its connection by the bifurcated projection 46 on the pawl 22 with 4 a point on the spring 44 near its end opposite the end lodged in the socket 42.

Wrenches of the type embodying the present invention have a basic mechanical movement in which oscillatory movement is converted into uni-directional rotary movement. In one position of the pawl 22 the ratchet 16 can rotate only in one direction, and in the alternate operating position of the pawl 22 the ratchet 16 can rotate only in the opposite direction. When the ratchet 16 rotates the pawl 22 remains in contact therewith, and due to the floating mount of this pawl, the shift lever 34 remains motionless. Likewise, the teeth 18 move past the teeth 24- substantially silently and without consequent wear or vibration. Hence, it is evident that wrenches embodying the invention enjoy a longer useful life than the conventional wrenches known heretofore.

It will be obvious to those skilled in the art that various changes may be made without departing from the spirit and the scope of the invention, and therefore the invention is not limited to what is described in the specification and illustrated in the drawing, but only as defined by the appended claims.

I claim:

1. A reversible ratchet wrench, comprising a handle secured to an operative head having an interior cavity, a cylindrical ratchet mounted rotatably within said cavity, said ratched having a plurality of ratchet teeth on its periphery and being secured to a work piece engaging member projecting to the exterior of the head, a movable pawl having a plurality of teeth adapted to cooperate with the ratchet teeth to limit the movement of the ratchet to selectively reversible uni-directional rotary movement, a shift plate mounted movably adjacent to the pawl, an exterior angularly movable shift lever connected to the shift plate for manual shifting thereof, and an elongated spring extending between and engaging opposite sides of the shift plate and connecting said plate to a projection on the pawl, whereby the pawl is mounted for floating movement with its teeth constantly maintained in resilient engagement with the ratchet teeth and the angular movement of the shift lever imparts corresponding shifting movement to the pawl through the spring con nection therewith.

2. A reversible ratchet wrench, comprising a handle secured to a head having an interior cavity, a cylindrical ratchet mounted rotatably within said cavity, said ratchet having a plurality of ratchet teeth on its periphery and being secured to a work piece engaging member projecting to the exterior of the head, a movable pawl having a plurality of teeth on opposite sides thereof adapted to cooperate with the ratchet teeth to limit the movement of the ratchet selectively reversible uni-directional rotary movement, said pawl being shiftable to bring the teeth on its opposite side alternatively into engagement with the ratchet teeth when the direction of rotation is selectively reversed, a shift plate mounted movably in sliding contact with the pawl, an exterior angularly movable shift lever connected to the shift plate for manual shift ing thereof, and elongated spring extending between and engaging opposite sides of the shift plate, and a projection on the pawl engaging the spring, whereby the pawl is capable of limited floating movement slidably on the shift plate while the pawl teeth are constantly maintained in resilient engagement with the ratchet teeth and the angular movement of the shift lever imparts corresponding shifting movement to the pawl through the spring connection therewith.

3. A reversible ratchet wrench, comprising a handle secured to a head having an interior cavity, a cylindrical ratchet mounted rotatably within said cavity, said ratchet having a plurality of ratchet teeth on its periphery and being secured to a work piece engaging member projecting to the exterior of the head, a movable "pawl having one one 'face thereof a plurality of teeth adapted to co operate with the ratchet teeth to lirnit'the movement of the ratchet to selectively reversible uni-directional rotary movement, the opposite face of the pawl being mounted in sliding engagement with the wall of the cavity and receiving strains imparted directly through the pawl as thrust strains rather than as shearing strains on the cooperating teeth, a shift plate mounted movably in sliding contact with the pawl, an exterior angularly movable shift lever connected to the shift plate for manual shifting thereof, a helical coiled spring extending between and having its opposite ends engaging opposite sides of the shift plate, and a projection on the pawl engaging said spring, whereby the pawl is capable of limited floating movement slidably on the shift plate while the pawl teeth are constantly maintained in resilient engagement with the ratchet teeth and the angular movement of the shift lever imparts corresponding shifting movement to the pawl through the spring connection therewith.

4. A reversible ratchet wrench, comprising a handle secured to a head having an interior cavity, a cylindrical ratchet mounted rotatably within said cavity, said ratchet having a plurality of ratchet teeth on its periphery and being secured to a work piece engaging member projecting to the exterior of the head, a movable pawl of generally trapezoidal configuration having on one face thereof corresponding to the base of its trapezoidal configuration a plurality of teeth adapted to cooperate with the ratchet teeth to limit the movement of the ratchet to selectively reversible uni-directional movement, the opposite face of the pawl being mounted in sliding engagement with the wall of the cavity and receiving strains imparted directly diagonally through the pawl as thrust strains rather than as shearing strains on the cooperating teeth, a discshaped shift plate mounted rotatably in sliding contact with the pawl, an exterior angularly movable shift lever connected to the shift plate for manual shifting thereof, a helical coiled spring extending between opposite sides of the shift plate, one end of the spring being lodged in a socket formed in one side of the shift plate, and a projection on the pawl engaging the spring at a point near the opposite end thereof, whereby the pawl is capable of limited floating movement slidably on the shift plate while the pawl teeth are constantly maintained in resilient engagement with the ratchet teeth and the angular movement of the shift lever imparts corresponding shifting movement to the pawl through the spring connection therewith.

5. A reversible ratchet wrench, comprising a handle secured to a head having an interior cavity, a cylindrical ratchet mounted rotatably within said cavity, said ratchet having a plurality of ratchet teeth on its periphery and being secured to a work piece engaging member projecting to the exterior of the head, a movable pawl of generally trapezoidal configuration having on one face thereof corresponding to the base of its trapezoidal configuration a plurality of teeth on opposite sides thereof adapted to cooperate with the ratchet teeth to limit the movement of the ratchet to selectively reversible uni-directional rotary movement, said pawl being shiftable to bring the teeth on its opposite sides alternatively into engagement with the ratchet teeth when the direction of rotation is selectively reversed, the opposite face of the trapezoidal pawl corresponding to its apex having a pair of projections mounted in sliding engagement with the wall of the cavity and receiving strains imparted directly diagonally through the pawl as thrust strains rather than as shearing strains on the cooperating teeth, a pin mounted in the cavity and projecting into engagement with the pawl between said pair of projections thereon to serve as a fulcrum about which the pawl rocks during shifting movement thereof, a disc-shaped shift plate mounted rotatably in sliding contact with the pawl, an exterior angularly movable shift lever connected to the shift plate for manual shifting thereof, a helical coiled spring extending between opposite sides of the shift plate, one end of the spring being lodged in a socket formed in 6 one side of the shift plate, and a projection on the pawl engaging said spring at a point near the opposite end thereof, whereby the pawl is capable of limited floating movement slidably on the shift plate while the pawl teeth are constantly maintained in resilient engagement with the ratchet teeth and the angular movement of the shift lever imparts corresponding shifting movement to the pawl through thespring connection therewith.

6. A reversible ratchet wrench, comprising a handle secured to a head having a large cylindrical interior cavity and a smaller cylindrical interior cavity intersecting one edge of the large cavity, a cylindrical ratchet mounted rotatably within the large cavity, said ratchet having a plurality of ratchet teeth on its periphery and being secured to a Work piece engaging member projecting axially to the exterior of the head, a movable pawl of generally trapezoidal configuration mounted rotatably within the smaller cylindrical cavity, said pawl having on one face thereof corresponding to the base of its trapezoidal configuration a plurailty of teeth adapted to cooperate with the ratchet teeth to limit the movement of the ratchet to selectively reversible uni-directional rotary movement, the opposite face of the trapezoidal pawl corresponding to its apex having a pair of projections curved to correspond with the curvature of the smaller cylindrical cavity and mounted in sliding contact with the wall of said cavity so that any strains to which the pawl is subjected when the Wrench is under load are imparted directly diagonally through the pawl as thrust strains rather than as shearing strains on the cooperating teeth, a pin mounted in the smaller cavity and projecting into engagement with the pawl between said pair of projections thereon to serve as a fulcrum about which the pawl rocks during shifting movement thereof, a discshaped shift plate mounted rotatably in the smaller cavity beneath the pawl and in sliding engagement therewith, an exterior angularly movable shift lever connected to the shift plate for manual shifting thereof, a helical coiled spring extending between opposite sides of the shift plate, one end of the spring being lodged in a socket formed in the shift plate, and a bifurcated projection on the pawl extending into straddling engagement with said spring at a point near one end of the spring, whereby the pawl is capable of limited floating movement slidably on the shift plate while the pawl teeth are constantly maintained in resilient engagement with the ratchet teeth and the angular movement of the shift lever imparts corresponding shifting movement to the pawl through the spring connection therewith.

7. The ratchet wrench defined in claim 6, wherein a flat S-shaped spring is mounted in the large cavity in sliding engagement with the cylindrical ratchet across an axial face thereof, one end of said S-shaped spring being in engagement with the disc-shaped shift plate and the other end of said S-shaped spring being in engagement with a diametrically opposite point on the side wall of the large cavity, said S-shaped spring imparting positive snap action to the shifting movement of the shift plate.

8. The ratchet wrench defined by claim 6, wherein the maximum limits of the angle of inclination to which the pawl is movable with respect to the axis of the wrench handle is within the range of about 25 to 35.

References Cited in the file of this patent UNITED STATES PATENTS 1,957,462 Kress May 8, 1934 2,957,377 Hare Oct. 25, 1960 3,019,682 Hare Feb. 6, 1962 FOREIGN PATENTS 1,005,095 France Dec. 12, 1951

Claims

1. A REVERSIBLE RATCHET WRENCH, COMPRISING A HANDLE SECURED TO AN OPERATIVE HEAD HAVING AN INTERIOR CAVITY, A CYLINDRICAL RATCHET MOUNTED ROTATABLY WITHIN SAID CAVITY, SAID RATCHED HAVING A PLURALITY OF RATCHET TEETH ON ITS PERIPHERY AND BEING SECURED TO A WORK PIECE ENGAGING MEMBER PROJECTING TO THE EXTERIOR OF THE HEAD, A MOVABLE PAWL HAVING A PLURALITY OF TEETH ADAPTED TO COOPERATE WITH THE RATCHET TEETH TO LIMIT THE MOVEMENT OF THE RATCHET TO SELECTIVELY REVERSIBLE UNI-DIRECTIONAL ROTARY MOVEMENT, A SHIFT PLATE MOUNTED MOVABLY ADJACENT TO THE PAWL, AN EXTERIOR ANGULARLY MOVABLE SHIFT LEVER CONNECTED TO THE SHIFT PLATE FOR MANUAL SHIFTING THEREOF, AND AN ELONGATED SPRING EXTENDING BETWEEN AND ENGAGING OPPOSITE SIDES OF THE SHIFT PLATE AND CONNECTING SAID PLATE TO A PROJECTION ON THE PAWL, WHEREBY THE PAWL IS MOUNTED FOR FLOATING MOVEMENT WITH ITS TEETH CONSTANTLY MAINTAINED IN RESILIENT ENGAGEMENT WITH THE RATCHET TEETH AND THE ANGULAR MOVEMENT OF THE SHIFT LEVER IMPARTS CORRESPONDING SHIFTING MOVEMENT TO THE PAWL THROUGH THE SPRING CONNECTION THEREWITH.