Patent Publication Number: US-3968708-A

Title: Adjustable wrench

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an improved wrench and more specifically to a wrench having an improved retaining assembly for releasably mounting a worm gear on the frame of the wrench. 
     A known adjustable open end wrench includes a worm gear which turns on a shaft or pin that is threaded on one end. The shaft is secured into a mating thread in the head of a wrench handle and locked in position by a staking operation. This known wrench includes a coil spring which is utilized to reduce end play between the worm gear and the slot or cavity in the wrench handle. 
     With this known wrench, the required thread tolerances between the tapped hole in the wrench handle and the threaded shaft are critical and troublesome. Tap breakage and resulting machine down time is expensive. Coil spring interferences between the shaft, the drilled hole and the counterbore in the worm gear also contribute to the cost of manufacturing the wrench. In addition, screwing the shaft into its position in the wrench handle is slow and occasional disassembly requirements are burdensome. 
     Another known wrench is disclosed in U.S. Pat. No. 1,431,451. This wrench utilizes a pair of pins to mount a worm gear in a gear cavity in the wrench handle. One of the pins is disposed in a hole in a cavity in the frame of the wrench. The outer end of this pin is received in a bore in the worm gear. The pin has a larger external diameter than the bore in the worm gear and cannot be telescoped into the bore of the worm gear. A second pin, which also has a larger outside diameter than the bore in the worm gear, presses the worm gear against the first pin under the influence of a biasing spring. When the jaws of the wrench disclosed in this patent are in an open position, the worm gear can be moved axially toward the fixed jaw against the influence of the biasing spring and could result in accidental or inadvertent disassembly of the wrench. Other adjustable wrench constructions are disclosed in U.S. Pat. Nos. 1,747,360; 3,580,115 and 3,673,896. 
     SUMMARY OF THE PRESENT INVENTION 
     The present invention relates to an adjustable wrench which utilizes a worm gear to effect movement of a jaw of the wrench. In accordance with a feature of the present invention, an improved retaining assembly is provided to releasably retain the worm gear in a gear cavity in the frame of the wrench. This retaining assembly includes a member, such as a plunger or pin, which is movable between an engaged position extending outwardly from a cavity in the worm gear into engagement with the frame of the wrench and a released position in which the retaining member is disposed substantially entirely within the cavity in the worm gear. When the retaining member is disposed within the cavity in the worm gear, the worm gear is at least partially released for movement out of the gear cavity in the frame of the wrench. 
     In one specific preferred embodiment of the invention, the retaining assembly includes two pin type retaining members which are telescopically received within a bore or cavity formed in the worm gear. The two pin members extend outwardly from opposite end portions of the worm gear into engagement with the frame of the wrench to hold the worm gear in the gear cavity. When the wrench is to be disassembled, one of the pins is telescoped substantially entirely into the cavity in the worm gear and the other pin is moved out of the cavity in the worm gear. This releases the worm gear so that it can move sideways out of the gear cavity in the frame of the wrench. 
     Accordingly, it is an object of this invention to provide a new and improved wrench wherein a worm gear is releasably mounted on the frame of the wrench by means of a retaining member which can be moved into a cavity formed in the worm gear to release the worm gear and thereby facilitate disassembly of the wrench. 
     Another object of this invention is to provide a new and improved wrench in which a worm gear is held in a cavity in the frame of the wrench by an improved retaining assembly which includes first and second members which are movable to a released condition in which one of the two members is disposed substantially entirely within a cavity in the worm gear and the second member is disposed entirely outside of the worm gear. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects and features of the present invention will become more apparent upon consideration of the following description taken in connection with the accompanying drawings wherein: 
     FIG. 1 is an illustration of an adjustable, open end wrench constructed in accordance with the present invention; 
     FIG. 2 is an enlarged fragmentary sectional view illustrating the relationship between fixed and movable jaws of the wrench, a worm gear for effecting movement of a jaw of the wrench, and a retaining assembly for releasably mounting the worm gear on the frame of the wrench; 
     FIG. 3 is an elevational view, taken generally along along the line 3--3 of FIG. 2, further illustrating the relationship of the worm gear to the frame and movable jaw of the wrench; 
     FIG. 4 is a fragmentary sectional view illustrating the worm gear retaining assembly in a released condition; 
     FIG. 5 is a fragmentary sectional view, similar to FIG. 2, illustrating a second embodiment of the invention; 
     FIG. 6 is an elevational view, taken generally along the line 6--6 of FIG. 5, further illustrating the construction of the second embodiment of the invention; and 
     FIG. 7 is a fragmentary sectional view illustrating the worm gear retaining assembly of FIG. 5 in a released condition in which the worm gear can be removed from the frame of the wrench. 
    
    
     DESCRIPTION OF SPECIFIC PREFERRED EMBODIMENTS OF THE INVENTION 
     An adjustable, open end wrench 10 constructed in accordance with the present invention, includes a worm gear 12 which is rotatable to move a jaw 14 toward or away from a fixed jaw 16 of the wrench. The worm gear 12 is rotatably mounted in a generally rectangular gear cavity or slot 20 formed in a frame 22 of the wrench 10 by an improved retaining assembly 24 (see FIG. 2). The worm gear 12 is disposed in meshing engagement with a rack gear 26 which is integrally formed with the movable jaw 14. 
     When the worm gear 12 is rotated in one direction, for example, clockwise as viewed in FIG. 3, the helical teeth of the worm gear 12 interact with the rack gear 26 to effect movement of the jaw 14 toward the fixed jaw 16. Similarly, rotation of the worm gear 12 in a counterclockwise direction (as viewed in FIG. 3) moves the jaw 14 away from the fixed jaw 16. The jaw 14 is slidably supported in known manner by a guideway 28 in the frame 22 of the wrench 10. 
     In accordance with a feature of the present invention, the retaining assembly 24 is releasable to enable the worm gear 12 to be moved out of the gear cavity 20 to facilitate disassembly of the wrench 10. The retaining assembly 24 includes a pair of coaxial plungers or pin members 32 and 34 which support the worm gear 12 for rotation about its central axis. The pins 32 and 34 extend axially outwardly from opposite ends of the worm gear 12 into engagement with pin cavity or recesses 36 and 38 formed in the frame member 22. The pin cavities 36 and 38 are part of a single cylindrical bore or passage which extends inwardly from a minor side surface 40 of the frame 22 through the gear cavity 20. The pins 32 and 34 have a circular cross sectional configuration so as to support the worm gear 12 for rotation about its central longitudinal axis which is coincident with the central axes of the pin members 32 and 34 and the central axes of the cavities 36 and 38. 
     When the wrench 10 is to be disassembled, an actuator rod 41 (FIG. 4) is inserted into the cavity 36 and pressed against a circular end of the pin member 32. This forces the pin 32 axially into a bore or cavity 42 formed in the worm gear 12. As the pin or retaining member 32 is telescoped into a relatively large diameter main section 44 of the bore 42, a cylindrical end portion 48 of the plunger 32 forces the pin 34 out of the bore or cavity 42 in the worm gear 12 into the pin cavity 38 in the frame 22. 
     Once the pin 32 has been telescoped entirely into the internal cavity 42 of the worm gear 12 and the cylindrical pin 34 has been telescoped into the cavity 28 in the frame 22, the worm gear 12 is free to move sidewardly out of the gear cavity 20. The application of a rightwardly directed force (as viewed in FIG. 3) against one side of the worm gear 12 will then cause the worm gear 12 to move through a rectangular opening 49 in a major side surface 50 of the frame 22. 
     Once the worm gear 12 has been moved out of the gear cavity 20, the retaining member or pin 34 is free to move axially out of the cylindrical pin cavity 38 under the influence of a coil spring 54. In addition, when the rightward force is removed from the end of the pin member 32, it is moved axially toward the left under the influence of a second coil spring 58 disposed in the worm gear bore 42. Of course, once the worm gear 12 has been removed from the gear cavity 20, the movable jaw 14 can be freely slid along the guideway 28 to fully disassemble the wrench. 
     When the wrench 10 is to be reassembled, the movable jaw 14 is reinserted into the guideway 28 in a position similar to the one shown in FIG. 2. The worm gear 12 is then positioned with its threads in engagement with the rack gear 26 on the movable jaw 14. Since at this time the pin 34 extends axially out of the frame cavity 38 under the influence of the biasing spring 54 and the pin 32 extends axially out of the worm gear cavity 32 under the influence of the biasing spring 58, the two pins interfere with movement of the worm gear 12 into the gear cavity 20. Therefore, the pin 34 is depressed against the influence of the biasing spring 54 and the pin 32 is retracted into the worm gear bore 42 against the influence of the biasing spring 58 (see FIG. 4). The worm gear is then moved sidewardly into the gear cavity 20. 
     When the two pins 32 and 34 have moved into axial alignment, the biasing spring 54 causes the pin 34 to move axially outwardly from the position shown in FIG. 4 to the position shown in FIG. 2. As this is occurring, the pin 32 is moved axially out of the bore 42 so that a cylindrical end portion 62 of the pin is received in the cylindrical pin cavity 36. The biasing spring 38 is then effective to apply a force against the pin member 34 to press an annular shoulder 64 on the pin member 32 against a sidewall 66 of the gear cavity 20. When the two pin members 32 and 34 move to the engaged position shown in FIG. 2, the worm gear 12 is supported for rotation on a cylindrical outer surface of a large diameter body portion 70 of the pin member 32 and on a cylindrical outer surface of the pin member 34. It should be noted that the worm gear 12 is pressed against the sidewall 74 of the gear cavity 20 by the spring 58 which is disposed between the cylindrical body portion 70 of the pin member 32 and an annular shoulder 76 formed in the worm gear bore 42. 
     When the wrench 10 is in the assembled position of FIG. 2, the retaining assembly 24 firmly holds the worm gear 12 against movement out of the gear cavity 20. Thus, the abutting engagement between the cylindrical surfaces of the pin members 32 and 34 and frame cavities 36 and 38 prevents the worm gear 12 from being moved sideways relative to the frame 22. The biasing spring 54 maintains the pin member 34 in the position shown in FIG. 2 so that the pin member 32 is not accidentally forced out of the cavity 36 under the influence of normal operating forces. Although pin type retaining members 32 and 34 having cylindrical outer surfaces have been illustrated in the drawings, it is contemplated that other types of retaining members could be utilized if desired. 
     The embodiment of the invention illustrated in FIGS. 5 through 7 is generally similar to the embodiment of the invention illustrated in FIGS. 1 through 4. However, in the embodiment of the invention of FIGS. 5 through 7, the worm gear is urged against a sidewall of the gear cavity by one of the retaining pins or plungers. Therefore, a single spring is utilized in the embodiment of the invention illustrated in FIGS. 5 through 7 to perform the functions of the two springs 54 and 58 of the embodiment of the invention illustrated in FIGS. 1 through 4. To avoid prolixity of description, components of the embodiment of FIGS. 5 through 7 which correspond to components of the embodiment of FIGS. 1 through 4 have been designated by similar numerals, the suffix letter a will be used in association with the numerals of FIGS. 5 through 7 to avoid confusion. 
     A worm gear 12a (FIG. 5) is rotatably mounted in a gear cavity 20a by a releasable retaining assembly 24a. The retaining assembly 24a includes a pair of coaxial retaining members or pins 32a and 34a. When the wrench 10a is in a fully assembled condition of FIG. 5, the pins 32a and 34a extend axially outwardly from opposite ends of the worm gear 12a into cylindrical cavities 36a and 38a formed in the frame 22a of the wrench 10a. Thus, the pin 32a includes a cylindrical outer end portion 62a which is disposed in the pin cavity 36a, a cylindrical main or body portion 70a which is disposed in a cylindrical main portion 44a of an axially extending bore or cavity 42a formed in the worm gear 12a. A cylindrical end portion 48a of the retaining member 32a is disposed in abutting engagement with a cylindrical end portion 100 of the pin 34a. 
     The cylindrical end portion 100 of the pin 34a is disposed in a cylindrical portion 102 of the worm gear cavity 42a. It should be noted that the cylindrical portion 102 and the cylindrical main portion 44a of the worm gear cavity 42a are disposed in a coaxial relationship with each other and with the central axis of the worm gear 12a. The pin 34a also includes a relatively large diameter cylindrical body portion 104 and a somewhat smaller diameter outer end portion 106 which are disposed in a coaxial relationship with the inner end portion 100 of pin 34a. 
     When the wrench 10a is to be disassembled, an actuator rod 41a is inserted into the cylindrical cavity 36a (see FIG. 7) to force the pin member 32a entirely into the worm gear cavity 42a. As the pin 32a is forced into the worm gear cavity 42a, the abutting engagement of a circular end surface of the pin 32a with a circular end surface of the pin 34a causes the pin 34a to be forced entirely into the cavity 38a against the influence of the biasing spring 54a. 
     Once the pin 32a has been forced entirely into the worm gear cavity 42a and the pin 34a has been forced entirely into the frame cavity 38a, the worm gear 12a can be removed from the gear cavity 20a by merely pressing the worm gear 12a  sideways in a direction perpendicular to the central axis of the worm gear. Of course, once the worm gear 12a has been removed from the gear cavity 20a, the movable jaw 14a can be easily moved along the guideway 28a to fully disassemble the wrench 10a. 
     When the wrench 10a is to be reassembled, it is merely necessary to depress the pin 34a into the frame cavity 38a and to insert the worm gear into the gear cavity 20a with the pin 32a in the bore 42a. When the pins 32a and 34a are in a coaxial relationship, the biasing spring 54a causes the pin 34a to move toward the left and extend the cylindrical outer end portion 62a of the pin member 32a into the pin cavity 36a. 
     As the pin 34a moves from the released position shown in FIG. 7 toward the engaged position shown in FIG. 5, an annular shoulder 112 on the body portion 104 of the pin member 34a moves into abutting engagement with an end surface 116 of the worm gear 12a. Therefore, when the wrench 10a is fully assembled, the pin member 34a applies an axially directed biasing force to the worm gear 12a to press it against the sidewall 66a of the gear cavity 20a. An annular shoulder 118 on the body portion 70a of pin member 32a prevents pin member 32a from being ejected through cavity 36a. 
     In view of the foregoing description it is apparent that an improved adjustable wrench 10 includes a worm gear 12 which is releasably held in a gear cavity 20 in the frame 22 of the wrench by a retaining assembly 24. The retaining assembly 24 includes a pair of pin or plunger members 32 and 34. During normal use of the wrench 10, the pin members 32 and 34 project outwardly from opposite ends of an axially extending cavity 42 in the worm gear 12 to support the worm gear for rotation about its central axis. When the wrench 10 is to be disassembled, the pin member 32 is pressed completely into the cavity 42 in the worm gear and the other pin member 34 is pressed completely into a cavity 38 in the frame 22 of the wrench. The worm gear 12 can then be moved sidewardly out of the gear cavity 20. When the wrench 10 is to be reassembled, the pin 32 is telescoped back into the cavity 42 in the worm gear while the other pin 34 is pessed into the cavity 38 in the frame 22 of the wrench. The worm gear 12 is then inserted into the gear cavity 20 and the pins are released.