Abstract:
There is disclosed an adjustable ratchet wrench including a disk member with ratchet teeth on its periphery and hub portions of reduced diameter on each side. A centrally disposed rectangular opening is provided in which a double acting lead screw is mounted. A pair of jaws are threadedly mounted on the lead screw for movement toward or away from each other dependent upon the direction of rotation of the lead screw. A two piece body is provided which defines an elongated handle and two parallel, spaced apart members which terminate in a generally circular, enlarged ratchet holding head having circular openings in which the hub portions of the ratchet disk are received. A pawl is provided for controlling the direction of ratchet movement.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to tools, and more particularly to a ratchet wrench having jaws which are adjustable to accomodate different size heads of fasteners. 
     Ratchet wrenches have been known in the tool art for many years and substantial number of patents have issued upon different configurations of ratchet wrenches. However, in general the prior art ratchet wrenches are considered to be more mechanically complicated than the wrench of the present invention and hence more expensive to manufacture without providing as good a performance as the wrench of the present invention. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, there is provided an improved, adjustable ratchet wrench which is characterized by simplicity of mechanical construction but which is durable and easy to use. The wrench of the present invention includes a body formed of two complementary side pieces which define an elongated handle portion and two parallel, spaced apart members each terminating in a generally circular, enlarged, ratchet holding head. A circular ratchet disk member having a plurality of ratchet teeth about its periphery is provided with hub portions of reduced diameter which extend from opposite sides of the disk. Each of the ratchet holding heads include coaxial circular openings for receiving the hub portions of the ratchet disk, supporting the ratchet disk member for rotation. 
     In a first embodiment, the ratchet disk member is made of two complementary parts in order to facilitate the mounting of a double acting lead screw for rotation in indentations formed inside the ratchet disk. The ratchet disk includes a centrally disposed rectangular opening for receiving the double acting lead screw and a pair of opposed jaw members are threadedly mounted upon the lead screw for movement selectively toward and away from each other dependent upon the direction of the rotation of the lead screw. Opposed faces of the jaw members include two obliquely angled planes defining a spread V shape facilitating the use of the wrench of the present invention on fastener heads of both square and hexagonal configuration. A pawl is provided for controlling the direction the ratchet disk member is permitted to rotate. 
     In a second embodiment, the ratchet disk member includes at least three parts, positioned as three layers. The centrally disposed rectangular opening for receiving the double acting lead screw and the pair of opposed jaw members is larger in the middle layer part then in the two outermost parts. The jaw members are constructed with extending flanges which fit in the groove formed by the enlarged opening in the middle part of the ratchet disk member. This provides additional support for the jaw members. Opposed bases of the jaw members include two obliquely angled planes defining a spread V shape with a cutout or notch formed at the point of the V to accommodate fastener heads of any polygonal configuration. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     Many objects and advantages of the invention will become apparent to those skilled in the art as a detailed description of embodiments of the invention unfolds in conjunction with the appended drawings wherein like reference numerals denote like parts and in which: 
     FIG. 1 is a plan view showing the rear side of a ratchet wrench in accord with a preferred embodiment of the invention; 
     FIG. 2 is a side elevation view of the wrench; 
     FIG. 3 is a partial plan view of the front side of the wrench; 
     FIG. 4 is a view generally taken along line 4--4 of FIG. 2, but with wrench jaws and adjustment mechanism deleted and a ratchet control pawl arrangement shown in plan rather than in cross section; 
     FIG. 5 is a cross sectional view taken along line 5--5 of FIG. 4; 
     FIG. 6 is a partial plan view of the front side of a second embodiment of the wrench; and 
     FIG. 7 is a cross sectional view taken along line 7--7 of FIG. 6; 
     FIG. 8 is a cross sectional view comparable to FIG. 7, showing a modification thereof. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, the wrench of the present invention is denoted generally by the reference numeral 10. It can be seen to include a main body 12 defining a handle 14. As best shown in FIG. 2 of the drawings, the body 12 is formed of two members 16A and 16B which are connected along parting line 18 and held fixed together by rivets 20A, 20B and 20C. When the members 16A and 16B are assembled as shown in FIG. 2, the body includes two parallel spaced apart members 22A and 22B which terminate in a generally circular, enlarged ratchet holding head 23 with each of the members 22A and 22B having apertures 24A and 24B formed therein for receiving for rotational movement a ratchet member 26. Pawl 34 is provided for controlling the direction in which the ratchet member 26 can rotate relative to the body 12 of the wrench. 
     FIG. 4 of the drawings illustrates the assembly and operation of the pawl and related elements. Each of the members 16A and 16B includes a recess 35 which is semicircular in cross section and which form, when members 16A and 16B are placed together, a recess circular in cross section for receiving spring 36 which biases a ball 38 against end 40 of the generally triangular shaped pawl 34. The pawl 34 is mounted for pivotal movement about the rivet 20A. When the pawl is positioned as shown, it will permit rotation of the ratchet in the clockwise direction as viewed in FIG. 4, with the end 42 of the pawl bearing against the teeth 44 of the ratchet to prevent movement in the opposite direction. As is conventional with such pawls, if pressure is applied against the side of the pawl from which end 47 extends, the pawl will pivot causing the ball 38 to bear on a different side of the end 40 biasing end 47 into contact with the teeth 44 on the ratchet disk, permitting rotation only in the counter clockwise direction. 
     In a first embodiment, the ratchet member 26 is formed of two complementary disks 28A and 28B which meet along parting line 32 and are held together by members 22A and 22B. A rectangular shaped opening 46 is formed in the member 26. A double acting lead screw 48 is rotatably mounted within the opening 46 and adapted to be driven by an integral thumb wheel 50. Jaws 54A and 54B of the wrench include base portions 56A and 56B respectively having threaded holes therethrough which mate with the threads on the lead screw for adjustment of the jaws relative to one another. 
     As is best seen in FIG. 3 of the drawings, the opposed faces of the jaw members 54A and 54B each include two obliquely angled planes 68 and 70 defining a spread V shape extending from the free end 72 of each of the jaw members a limited distance determined by a face 74 normal to the faces of 68 and 70. Provision of the face 74 prevents a fastener, such as a bolt head, which the wrench is engaging interfering with the operation of the thumb wheel 50. Provision of the spread V configuration of the jaw members permits use of the wrench on either square or hexagonal fastener heads. 
     The structure of the complementary disks 28A and 28B can best be seen with respect to FIGS. 4 and 5 of the drawings. Thus, each of the complementary disks include a pair of opposed slots 52 extending from the opening 46 for receiving the thumb wheel 50. In addition, a pair of opposed notches 60 are provided along a diameter which, when the two complementary disks are placed in opposing relationship, form a recess for receiving reduced diameter end portions of the thumb lead screw 48 supporting the lead screw for rotational movement. Each of the disks also include a pin 62 and a blind hole 64. When the complementary disks are assembled, the pin 62 of one of the disks is received within the blind hole 64 of the other disk for the purpose of preventing rotation of one of the disks relative to the other. The portion of each of the disks on which the ratchet teeth 44 are formed are suitable of approximately the same diameter as the diameter of the circular portion of the ratchet holding head 23, with each of the disks including a hub portion 66 of reduced diameter adapted to be received in the aperture 24 of the associated member 22. 
     A second embodiment of the invention is shown in FIGS. 6 and 7. The wrench therein is indicated generally by the reference numeral 106. Referring to FIG. 7, it can be seen that ratchet member 26 is comprised of three portions in layers. The middle portion, disk 80B, has ratchet teeth 28 formed about the periphery thereof. The outer portions, disks 80A and 80C, form the hubs of the ratchet member 26, fitting in the apertures 24A and 24B of spaced apart handle members 22A and 22B, respectively. Fasteners 90 (shown only in FIG. 6) hold the three disks 80A, 80B, and 80C together and prevent rotation of the disks relative to one another. 
     Each of the three disks 80A, 80B and 80C has a rectangular opening 46 therein to receive lead screw 48. The hold 46B in middle layer disk 80B is wider than the holes 46A and 46C in outer disks 80A and 80C, respectively. As a consequence, grooves 87 are formed on the opposite sides of the rectangular opening 46. The two jaws 81 of wrench 106 have flanges 82 extending outwardly into the grooves 87 of ratchet member 26. The purpose of providing the flanges 82 in grooves 87 is to ensure that jaws 81 hold firmly in position under the stress of operating on a nut or bolt. In particular, the purpose is to counteract the tendency of jaws 81 to spread apart from each other at the free ends of the jaws. In FIG. 7, the spaces between flanges 82 and the surfaces of grooves 87 are exaggerated for purposes of illustration. For best results, fit between flanges 82 and grooves 87 is close. 
     The jaws 81 of the second embodiment differ from the jaws of the first embodiment, besides the flanges 82, in that at the intersection of the front faces 68 and 70 there is provided a notch or cutout 86, preferably rectangular. The purpose of the notch 86 is to enhance the gripping power of the jaw members on a four sided fastener head. 
     FIG. 8 shows a modification of the embodiment in FIGS. 6 and 7, a wrench indicated generally by the reference numeral 108. In the modified wrench, there are four layers comprising the ratchet member 26. Disk 94B has the ratchet teeth 28 formed thereon, while disks 94B and 94C form the hub portions fitting in handle members 22. In addition, there is a disk layer 94D that is adjacent disk 94A. The rectangular opening 46A in disk 94A is larger than the rectangular openings 46D and 46B in adjacent layers. As with wrench 106, there are formed grooves 97 on opposite sides of jaws 91, but in this case the grooves are in the hub layer disk 94A. Outwardly extending flanges 92 from jaws 91 closely fit in the grooves 97. 
     The modification shown in FIG. 8 provides an advantage over that illustrated in FIGS. 6 and 7. When the jaws 81 or 91 tend to spread under load, their tendency is to move away from each other, pivoting about their point of support on the lead screw 48. The flanges 82 of the wrench 106 counteract this tendency, providing additional points of support, located near the region of pivoting. The design of wrench 108 goes further by moving the flanges 92 away from the lead screw pivot point. This provides points of support between lead screw 48 and the free ends of jaws 91 where the load is exerted. As a result, the jaws 91 are provided with even greater stability than jaws 81. 
     From the foregoing, it can be seen that there is provided a ratchet wrench comprising only ten to twelve parts and three fasteners. Assembly of the wrench according to the first embodiment is quite simple in that it is only necessary to position the lead screw with the jaws mounted thereon on one of the disk members 28 with the reduced end portions of the lead screw positioned in the opposed notches 60. The second disk member is then laid over the first disk member with the pin 62 of each disk member inserted in the blind hole 64 of the other disk member. The resultant disk assembly is then placed into the aperture 24 with the reduced diameter hub portion 66 of one disk extending into the aperture 24. The fastener 20A can then be positioned in the appropriate hole of the member 16 and the pawl 34, spring 36, and ball 38 positioned as shown in FIG. 4. The remaining member 16 is then positioned similarly with respect to the disk assembly and pawl assembly and held together by the three fasteners. The ratchet wrench according to the second embodiment is similarly assembled. The simplicity of construction provides improved reliability. The structures of the ratchet disk and handle members are such that they can be readily formed of sintered metal of punched from flat plate stock providing further manufacturing economies and a structure characterized by great physical strength. 
     Although the invention has been described with regard to particular preferred embodiments thereof, changes and modifications will become apparent to those skilled in the art in view of the foregoing description and the invention is intended to be limited only as defined in the claims.