US3233481A

US3233481A - Ratchet wrench

Info

Publication number: US3233481A
Application number: US318988A
Authority: US
Inventors: Louis E Bacon
Original assignee: Kelsey Hayes Co
Current assignee: Kelsey Hayes Co
Priority date: 1963-10-25
Filing date: 1963-10-25
Publication date: 1966-02-08
Anticipated expiration: 1983-02-08

Description

L. E. BACON RATGHET WRENCH Feb. 8, 1966 Filed Oct. 25, 1965 INVENTOR Louis E. Bacon ATTORNEY United States Patent 3,233,481 RATCHET WRENCH Louis E. Bacon, Canton, Ohio, assignor, by mesne assignments, to Kelsey-Hayes Company, a corporation of Delaware Filed Oct. 25, 1963, Ser. No. 318,988 6 Claims. (Cl. 8163) This invention relates to ratchets, and more particularly to ratchet wrenches having a reversing shifter mechanism. In one well known type of ratchet wrench a handle is operatively connected by means of a ratchet and pawl -mechanism with a rotatable head, and the direction of rotation of the head may be reversed by means of a shifter mechanism to cause the head to be rotated alternately in opposite directions. Such .ratchets may be subdivided into those of the center shifter type, wherein the shifter is located centrally of the head, and remote shifters wherein the shifter may be located remotely thereof on the handle. Ratchets of the center shifter type are generally more economical toproduce, dueto their requirement of fewer parts and less machining than 'usually the case in the remote shifter type. However, a disadvantage frequently encountered heretofore in the center-shifter type is difliculty in actuating the shifter mechanism with only one hand. Thus, due to the lack of sufilcient leverage in the shift mechanism of the center shifter type ratchets, as a practical matter it has been necessary to employ two hands to accomplish shifting, one hand to hold the handle steady and the other hand to operate the shift lever.

- One of the most important disadvantages encountered in the ratchet wrenches produced commercially heretofore, has been the difliculty of disassembly and reassembly of the ratchets in the field, whenever it becomes necessary to replace any worn parts. The particular interlocking of the internal mechanism in the prior art ratchet wrenches has made such disassembly and reassembly a very tricky operation requiring considerable kill and experience for accomplishment. Furthermore, in the prior art constructions the relationship of the internal moving parts has been such that jamming could readily occur.

An object of the present invention is to provide a new and improved ratchet wrench having a simplified interlocking of its internal parts to permit easy disassembly and reassembly thereof.

Another object of the invention is to provide a new and improved reversing shifter mechanism for a reversible ratchet wrench, having leverage sufiicient to facilitate the shifting operation.

Still-another object of the invention is to provide a new and improved ratchet wrench of rugged and sturdy construction which is efficient and reliable in operation.

Other objects and advantages of the invention will become evident in the following detailed description of a specific embodiment thereof, when considered in conjunction with the appended claims, wherein:

FIG. 1 is a top plan view of a ratchet wrench embodying the invention, with the handle portion thereof omitted;

FIG. 2 is a vertical sectional view taken on the line 2-2 of FIG. 1, showing the interlocked internal mechanism, and the shifter body and the pawl pin being shown in elevation;

FIG. 3 is a horizontal sectional view taken along the line 33 of FIG. 2, showing the ratchetand pawl mechanism in one of its alternate operating positions;

FIG. 4 is a view corresponding to that of FIG. 3, but showing the ratchet and pawl in their reversed operating position;

FIG. 5 is a side elevation view of the shifter, showing the interlock slot formed in the shifter body;

FIG. 6 is an end elevation view of said shifter, and

3,233,48l Patented Feb. 8, 1966 FIG. 7 is a fragmentary sectional view corresponding to that of FIGS. 3 and 4, showing the shifter body turned to a position of non-interlocking with the pawl to permit disassembly.

In the illustrated ratchet wrench, a generally cylindrical hollow head portion 10 may be secured to an elongated handle portion (not shown) in a one-piece integral construction, or the handle may be connected pivotally to the head by means of a hinge, for which purpose a counten-bored socket 12 is provided in a projecting lug 14 formed on one side of the head portion 10 of the illustrated wrench. Rotatably mounted within the hollow head portion 10 is a generally cylindrical core 16, and a work piece engaging projection 18 of the type employed in conventional socket wrenches is secured integrally to the body of the core 16 and projects from one side of the head 10, as shown in FIG. 2.

The cylindrical cavity defined by the hollow interior of the head portion 10 of the ratchet wrench is provided with a circumferential row of ratchet teeth 20, which cooperate with a plurality of teeth 22 formed on opposite ends of a pivotally mounted double-ended pawl 24, best shown in FIGS. 3 and 4. The pawl 24 is removably pivotally mounted on a cylindrical pawl pin 26 fitted snugly within a recess formed in the core 16 parallel to but offset from the axis thereof. A shifter having a generally cylindrical body 28 is rotatably fitted snugly within another recess in the core 16, spaced from and parallel to the recess for the pawl pin 26, and off center with respect to the axial center of the core 16. The shifter body 28 is provided at one. end thereof with an integral cover plate 30 above which projects an integral tapered shift lever 32 designed for finger actuation by a mere flick of an operators finger or thumb. The cover plate 30 covers the two above-mentioned recesses formed in the core 16, and it retains the pawl pin 26 in place, so that the pawl 24 and its pin 26 cannot be removed from the core 16 until the shifter body 28 is first detached therefrom.

The pawl 24 is provided with an arcuate surface 34 midway between its opposite ends, and cooperating with this surface 34 is a spring pressed plunger 36 having a rounded nose 38 to facilitate its sliding movement across the surface 34. The plunger 36 is mounted slid'ably within a transverse socket 40 disposed at right angles with respect to the axis of the shifter body 28, as is best shown in FIGS. 5 and 6, and the plunger 36 is urged outwardly by a spring 42 to maintain the rounded nose 33 in contact with the arcuate surface 34. It is evident that rotary movement of the shifter body 28, by finger actuation of the lever 32 through a small angle, causes the plunger 36 to travel across thearcuate surface 34 between opposite ends thereof, and that in doing so the plunger 36 moves with snap action past the dead center of the surface 34.

When the pawl 24 and the plunger 36 are in the operating position in which they are shown in FIG. 3, the core 16 and its work piece engaging projection 18 are permitted to rotate in one direction, the teeth 22 being held in resilient ratchetting engagement with the circumferential row of teeth 20. Angular movement of the finger actuated shift lever 32 causes the plunger 36 to slide across the surface 34 past dead center and snap into the reverse operating position shown in FIG. 4, .to allow the core 16 to rotate in the opposite direction.

The movement of the shifter body 28, and consequently of the plunger 36 also, is limited by means of stop surfaces 44 formed on opposite sides of one end of the cover plate 30, which stop surfaces 44 abut against a portion of a circular retaining rim 46 formed at one end of the cylindrical cavity defined by the hollow interior of the head 10. The core 16 is shown with one end thereof abutting against the rim 46 in FIG. 2, and the other end of the core 16 is held within the head by means of a removeable snap ring 48. Thus, the entire internal mechanism may be removed for disassembiy, simply by detachment of the snap ring 48. Then the shifter body 28 may be withdrawn from the core to by turning said body until a cutaway portion forming a vertical flat surface 50 thereon is brought nearly or approximately into alignment with a corresponding fiat surface 52 formed on the interior of and extending across the core 16, as is shown in FIG. 7. During this movement the rounded nose 3% of the plunger 36 is turned away from the pawl 24, counterclockwise as viewed in FIGS. 3 and 4, and the plunger 36 is retracted completely into the socketdt} by engagement of its nose 3% with a portion of the recess in which the shifter body 28 is mounted.

During normal operation, in the two alternate operating positions illustrated in FIGS. 3 and 4, a portion of the pawl 24 just beyond the arcuate surface-34 thereon is placed into interlocking engagement with the wall surfaces of a transverse interlock slot 54 formedinthe shifter body 28. The pawl 24 is constantly urged toward, one or the other of its alternate operating positions due to the pressing action of the spring pressed plunger 36, thereby maintaining interlocking and ratchetting during normal operation. However, when the shifter body 28 is turned to cause complete retraction of the plunger 36, the resultant detachment of the plunger 36 from the arcuate surface 34 allows the pawl 24 to remain in its dead cent r position, or in its last ratchetting position, as shown in FIG. 7. Furthermore, in this disassembly position the above-described interlocking is terminated by the turning of the cutaway fiat surface 50 to a point adjacent to the arcuate surface 34, thereby providing clearance therebetween and facing the slot 54 away from the pawl 24,'so that the shifter body 28 may thereupon be withdrawn from the core 16. Completion of the disassembly operation at this stage merely requires the sliding out of the pawl 24 and the pawl pin 26 from the core 16, which is made possible by the prior removal of the cover plate 30, and at that time the plunger 36 and its spring 42 then being unrestrained can pop out of the socket 40. Reassernbly of ratchet devices embodying the present invention may be accomplished by performing in reverse order the abovedescribed steps of disassemb'ly.

The disassembly of the ratchet devices known heretofore has usually required the insertion of a screwdriver, or some other small-bladed instrument, between the pawl and the plunger to force retraction of the plunger into its socket, and this has been an intricate operation due to the small size of the ratchet devices with which the present invention is concerned. In accordance with the present invention such retraction of the plunger is achieved merely by turning the shifter body until the nose of the plunger is engaged by the wall of the recess in which the shifter is mounted, which is quite an easy operation.

Due to the novel interlocking between the pawl 24 and the wall surfaces of the interlock slot 54 in the shifter body 28, ratchet devices embodying the present invention are rendered sturdy and reliable in operation, with little likelihood of the plunger or pawl becoming jammed. Furthermore, due to the offset of the turning axis of the shifter body 28 with respect to that of the core 16, the shifter lever 32 is provided with sufficient leverage to facilitate the shifting operation, requiring only a flick of an operators finger or thumb. It should be observed that the taper of the shift lever 32, which slopes downwardly in a direction away from the wrench handle and is highest at a point adjacent to the lug 14 connecting with the handle, serves to guide the operators thumb or finger to the highest point on the lever 32, thereby insuring that the maximum leverage is obtained. It should also be noted that the arcuate surface 34 functions during normal operation of the ratchet device as a carnming surface 'en- ,gaged by the plunger 3 6 as a cam, to control the pivotal movement of the pawl 24 and to effect reversal of the ratchet device.

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, as defined by the appended claims.

I claim:

1. In a ratchet device, a generally cylindrical head having a cylindrical internalcavity extending therethrough and provided with a circumferential row of ratchet teeth in said cavity, a cylindrical core mounted rotatably in said cavity and having joined thereto a work piece engaging projection extending outwardly from the head, a doubleended pawl mounted pivotally in said core and having pawl teeth at opposite ends thereof cooperating with the ratchet teeth in two alternate operating positions into which said pawl may be pivotally moved, ratchetting engagement of the ratchet teeth with the pawl teeth at one end of the pawl permitting rotation of the core in one direction and pivoting of the pawl into its alternate operating position to engage the teeth at the opposite end of the pawl permitting rotation in the reverse direction, a shifter including a generally cylindrical shifter body mounted rotatably in the core and joined to a shift lever projecting outwardly from the head, a spring pressed plunger mounted slidably in the shifter body and normally urged into engagement with the pawl, said plunger normally urging one end or the other of the pawl into engagement with the ratchet teeth and being effective when the shift lever is actuated to cause pivoting of the pawl for reversal of the direction of rotation of the core, said shifter body having a slot which is normally in interlocking engagement with the pawl when the pawl is pivoted to its two alternate operating positions but is freed from interlocking when the shifter body is turned to a disasse-mhly position wherein the slot faces away from the pawl, and means for normally preventing turning of the shifter body to its disassembly position until the shifter body is removed from the head.

2. In a ratchet device, a generally cylindrical head having a cylindrical internal cavity extending therethrough and provided with a circumferential row of ratchet teeth in said cavity, a cylindrical core mounted rotatably in said cavity and having joined thereto a work piece engaging projection extending outwardly from the head, a double-ended pawl mounted pivotally in said core and having pawl teeth at opposite ends thereof cooperating with the ratchet teeth in two alternate operating positions into which said pawl may be pivotally moved, ratchetting engagement of the ratchet teeth with the pawl teeth at one end of the pawl permitting rotation of the core in one direction and pivoting of the pawl into its alternate operating positionto engage the teeth at the opposite end of the pawl permitting rotation in the reverse direction, a shifter including a generally cylindrical shifter body mounted rotatably in the core and joined to a shift lever projecting outwardly from the head, a spring pressed plunger mounted slidably in a transverse socket in the shifter body, said plunger being normally pressed into engagement with the pawl and urging one end or the other of the pawl into engagement with the ratchet teeth, said pawl being shifted for reversal of the direction of rotation of the core by angular movement of the shift lever to cause a corresponding angular movement of the plunger pressed against the pawl, said shifter body having an interlock slot which is normally in interlocking engagement with the pawl when the pawl is in its two alternate operating positions but is freed from interlocking when the shifter is further turned to a disassembly position wherein the slot faces away from the pawl, said plunger being completely retracted by said further turning of the shifter thereby disengaging the pawl for disassembly, and

stop means for preventing such further turning of the shifter until said body is first disassembled from the head. 3. The ratchet device defined by claim 2, wherein the double-ended pivoted pawl is provided midway between its ends with an arcuate cam surface against which the spring pressed plunger is normally urged into sliding contact, said plunger sliding across said arcuate cam surface from one end to the other during pivotal movement of the pawl between its alternate operating positions, interlocking between the pawl and the shifter body occurring beyond the ends of the arcuate surface, and said surface providing clearance for disassembly of the shifter from the pawl when the pawl is allowed to pivot to its dead center position.

4. The ratchet device defined by claim 2, wherein the core is provided with a recess in which the shifter body is rotatably mounted, turning of the shifter body into its disassembly position brings the plunger into engagement with a portion of said recess to cause the plunger to become completely retracted into its socket in the shifter body, and said core and said body being provided with flat surfaces which become aligned when the shifter body is in its disassembly position, thereby providing clearance for disassembly.

5. In a ratchet device, a generally cylindrical head having a cylindrical internal cavity extending therethrough and provided with a circumferential row of ratchet teeth in said cavity, a cylindrical core mounted rotatably in said cavity and having joined thereto a work piece engaging projection extending outwardly from the head, a pawl pin mounted removably in a first recess in said core offset from the center thereof, a double-ended pawl mounted pivotally on said pin and having pawl teeth at opposite ends thereof cooperating with the ratchet teeth in two alternate operating positions into which said pawl may be pivotally moved, ratcheting engagement of the ratchet teeth with the pawl teeth at one end of the pawl permitting rotation of the core in one direction and pivoting of the pawl into its alternate operating position to engage the teeth at the opposite end of the pawl permitting rotation in the reverse direction, ashifter including a generally cylindrical shifter body mounted rotatably in a second recess in the core spaced from the first recess and also offset from the center of the core, a tapered shift lever projecting outwardly from the head, the taper of the shift lever and the offset of the recess in which the shifter is mounted serving to provide lever-age to facilitate angular movement of the shift lever, a spring pressed plunger mounted slidably in a transverse socket in the shifter body, said plunger being normally pressed into engagement with the pawl and urging one end or the other of the pawl into engagement with the ratchet teeth, said pawl being shifted for reversal of the direction of rotation of the core by angular movement of the shift lever to cause a corresponding angular movement of the plunger pressed against the pawl, said shifter body having an interlock slot which is placed in interlocking engagement with the pawl when the pawl is pivoted to its two alternate operating positions but is freed from interlocking when the shifter is turned further to a disassembly position wherein the slot faces away from the pawl, said plunger being completely retracted by said further turning of the shifter body to its disassembly position by engagement with a portion of the second recess thereby disengaging the pawl for disassembly, and stop means for preventing such further turning of the shifter body until said body is first disassembled from the head.

6. The ratchet device defined by claim 5, wherein the shifter body is provided with a cover plate above which projects the tapered shift lever, said cover plate covering said first and second recesses and thereby normally retaining the pawl and its pawl pin within the core, and opposite side edges of the cover plate serve as stop surfaces abutting alternately on opposite sides of the rim of the internal cavity in the head, thereby providing the stop means for preventing turning of the shifter body beyond the limits of the normal operating positions to the disassembly position until said shifter body is first removed from the head.

References Cited by the Examiner UNITED STATES PATENTS 655,908 8/1900 Morse 8163 1,078,059 11/1913 Mossberg 74157 X WILLIAM FELDMAN, Primary Examiner.

Claims

1. AIN A RATCHET DEVICE, A GENERALLY CYLINDRICAL HEAD HAVING A CYLINDRICAL INTERNAL CAVITY EXTENDING THERETHROUGH AND PROVIDED WITH A CIRCUMFERENTIAL ROW OF RATCHET TEETH IN SAID CAVITY, A CYLINDRICAL CORE MOUNTED ROTATABLY IN SAID CAVITY AND HAVING JOINED THERETO A WORK PIECE ENGAGING PROJECTION EXTENDING OUTWARDLY FROM THE HEAD, A DOUBLEENDED PAWL MOUNTED PIVOTALLY IN SAID CORE AND HAVING PAWL TEETH AT OPPOSITE ENDS THEROF COOPERATING WITH THE RATCHET TEETH IN TWO ALTERNATE OPERATING POSITIONS INTO WHICH SAID PAWL MAU BE PIVOTALLY MOVED, RATCHETTING ENGAGEMENT OF THE RATCHET TEETH WITH THE PAWL TEETH AT ONE END OF THE PAWL PERMITTING ROTATION OF THE CORE IN ONE DIRECTION AND PIVOTING OF THE PAWL INTO ITS ALTERNATE OPERATING POSITION TO ENGAGE THE TEETH AT THE OPPOSITE END OF THE PAWL PERMITTING ROTATION IN THE REVERSE DIRECTION, A SHIFTER INCLUDING A GENERALLY CYLINDRICAL SHIFTER BODY MOUNTED ROTATABLY IN THE CORE AND JOINED TO A SHIFT LEVER PROJECTING OUTWARDLY FROM THE HEAD, A SPRING PRESSED PLUNGER MOUNTED SLIDABLY IN THE SHIFTER BODY AND NORMALLY URGED INTO ENGAGEMENT WITH THE PAWL, SAID PLUNGER NORMALLY URGING ONE END OF THE OTHER OF THE PAWL INTO ENGAGEMENT WITH THE RATCHET TEETH AND BEING EFFECTIVE WHEN THE SHIFT LEVER IS ACTUATED TO CAUSE PIVOTING OF THE PAWL FOR REVERSAL OF THE DIRECTION OF ROTATION OF THE CORE, SAID SHIFTER BODY HAVING A SLOT WHICH IS NORMALLY IN INTERLOCKING ENGAGEMENT WITH THE PAWL WHEN THE PAWL IS PIVOTED TO ITS TWO ALTERNATE OPERATING POSITIONS BUT IS FREED FROM INTERLOCKING WHEN THE SHIFTER BODY IS TURNED TO A DISSASSEMBLY POSITION WHEREIN THE SLOT FACES AWAY FROM THE PAWL, AND MEANS FOR NORMALLY PREVENTING TURNING OF THE SHIFTER BODY TO ITS DISASSEMBLY POSITION UNTIL THE SHIFTER BODY IS REMOVED FROM THE HEAD.