Patent Publication Number: US-4649776-A

Title: Extension for socket tool drive system

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a tool which is used to apply a torque to a nut, bolt, screw or the like for purposes of installing or removing the nut, bolt screw, or other parts situated in places inaccessible to ordinary hand tools. The device of the invention is especially useful in conjunction with the assembly or repair of airplanes or motor vehicles or in any location which is restricted in access to conventional socket wrench sets, screwdrivers, and adjustable wrenches. 
     Several devices have been proposed for providing a remote driver to apply torque to a nut or bolt through a gear train or chain. U.S. Pat. No. 4,374,480 to Diaz teaches an extension wrench for transmitting a torque to a fastener. The extension wrench comprises an elongated frame, housing a driven gear at one end, a driving gear at the opposite end and a meshing gear train between the driving gear and driven gears which transmits torque from the driving gear to the driven gear. The gears have no shafts for support but instead, each gear is inserted into a closely fitting circular recess in the elongated frame. By this design, the peripheral edge of each gear bears against the close fitting circular recess. The consequence of this gear recess arrangement is that clearances must be provided between the ends of the teeth of the gear and the recess. This allows the gear to move slightly, thereby, bearing unevenly against the recess wall. Further, the misalignment of these gears causes a shift of the entire load to one edge of the tooth with resulting excessive stress being created. 
     U.S. Pat. No. 4,374,479 to Minotti teaches a tool for transmitting torque from a driving member to a work piece and comprises a plurality of serially engaging gears. In Minotti, gears bear both on central shafts, about which each gear rotates, and also on a coaxial cylindrical shoulder extending outwardly from opposites sides of otherwise flat generally circular surfaces of the gears. A housing having an upper part, and a lower part each with a recess for receiving the shoulder portion, includes holes to receive the central shaft about which the gears rotate. A major drawback of the tool taught by Minotti is that the frame or housing supporting the gear frame is open, thereby allowing dirt or metal chips to enter the gear train and aggravate wear and breakage of the gear system. Further, bolting down the housing parts of Minotti increases the sliding friction at the bearing surface of the gears, thereby causing the device to be inefficient. 
     SUMMARY AND OBJECTS OF THE INVENTION 
     It is an object of the invention to provide a new and improved wrench to reach a nut or bolt with restricted access, where conventional wrenches are not practical to use because of lack of clearance. 
     It is another object of the invention to provide a new and improved gear, for a wrench assembly, wherein gear teeth are cut into a disk only on one side so that the second side may act as a bearing. 
     Still another object of the present invention is to provide a new and improved gear for a wrench assembly, which gear operates within the wrench assembly in a smooth and vibrationless manner. 
     Another object of the present invention is to provide a wrench assembly having gears which are configured so as to have optimum strength, optimum fatigue, and wear properties when used in the wrench assembly. 
     It is another object of the invention to provide a torque transfer device having first and second housing parts and a gear train, wherein the gears are designed to fit within the housing such as to insure ease of manufacture and ease of inspection of the gear train within the housing. 
     Yet another object of the present invention is to provide a torque transfer device for transmitting torque from a driving member to a work piece, the device including housing parts having annular recesses therein which act as bearing surfaces for gears in a gear train. 
     Still another object of the invention is to provide a torque transfer device, for use with wrenches, having housing parts with recesses to accept gears wherein, the recesses are identical and are adapted to receive a gear and act as a bearing surface for the gears bearing. 
     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a perspective view showing the torque transfer device of the invention, a driver device for applying torque and a socket device for engagement with a bolt or the like; 
     FIG. 2 is a top plan view of a torque transfer device of a first embodiment of the invention, with the top housing part removed; 
     FIG. 3, is a plan view of a housing part of the torque transfer of a first embodiment of the invention; 
     FIG. 4 is a sectional view of a first embodiment of the present invention. 
     FIG. 5 is a detailed sectional view showing a driven or drive gear engaging an idler gear of the embodiment of FIG. 4; 
     FIG. 6 is a sectional view of another embodiment of the invention; 
     FIG. 7 is a perspective view of a driven or drive gear of both embodiments of the invention; 
     FIG. 8 is a perspective view of an idler gear of the embodiment of FIG. 4; 
     FIG. 9 is a perspective view of an idler gear of the embodiment of FIG. 6; 
     FIG. 10 is a top plan view of a torque transfer device of the embodiment of FIG. 6, with the top housing part removed; and, 
     FIG. 11 is a plan view of a housing part of the torque transfer device shown in FIG. 6. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now in detail to FIG. 1, there is illustrated a torque wrench assembly or torque transfer device T having a first end 2 and a second end 4. Torque wrench assembly T is formed of a lower housing portion 6 and a cooperating upper housing portion 8. At first end 2 of the torque converter assembly T there is a multi-faceted central hole 10, which can be square or hexagonal in crosssection, and which is adapted for receiving conventional socket set drivers, extension shafts, wrenches and screwdrivers. In FIG. 1, a conventional socket set driver 12 is shown. At second end 4 of torque wrench assembly T there is a multi-faceted hole 14 which can be of square of hexagonal cross-section. The hole 14 is adapted for receiving a stud member or the like 16, as best shown in FIG. 4 which snaps into the multi-faceted hole 14 so as to be positioned to receive a socket member 18 which snaps on said member 16. Socket set driver 12, stud member 16 and socket member 18 need not be further described as they are available and are in common use by persons with ordinary skill as a mechanic. 
     FIGS. 2, 3, 4, 5, and 8 
     Referring now in detail to FIGS. 2, 3, 4, 5 and 8, a torque wrench assembly is shown having idler disks or idler gears 20. As best shown in FIG. 8, idler gear 20 includes an annular peripheral bearing surface 22, cut-out portions 24 forming gear teeth 26 and reduced bearing surface 28. As is best seen in FIG. 2, idler gears 20a, 20b, 20c, 20d, 20e, 20f and 20g are positioned within idler gear recesses 30a, 30b, 30c, 30d, 30e, 30f and 30g, respectively. Idler gear 20a is positioned within lower housing portion 6a so that the reduced bearing surface 28 of idler gear 20a is within recess 30a. Idler gear 20b is positioned within housing portion 6a so that annular peripheral bearing surface 22 of idler gear 20b is within recess 30b. Idler gear 20c, 20e and 20g are positioned within housing portion 6a with an orientation similar to that of idler gear 20a. Idler gears 20d and 20f are positioned within housing 6a with an orientation similar to that of idler gear 20b. By this arrangement, gears 20b, 20d and 20f are positioned so that the annular peripheral bearing surface 22 of each idler gear 20b, 20d and 20f bear against respective bearing surfaces 32b, 32d, and 32f. Idler gears 20a, 20c, 20e and 20g are seated within respective recesses so that the reduced bearing surface 28 of each of the idler gears is seated on respective recess base portions 34a, 34c, 34d and 34g. 
     FIG. 7 shows a tool receiving gear 36 having an annular peripheral bearing surface 38, cut-out portions 40 and gear teeth 42. A reduced bearing portion or shaft portion 44 is provided with multifaceted hole 10 extending through shaft 44. 
     As can best be seen in FIG. 2, a first tool receiving gear 46 and a second tool receiving gear 48 are positioned within respective tool gear recesses 50 and 52 of lower housing portion 6a. By this arrangement, when first tool gear 46 is rotated, gear teeth 42 of first tool gear 46 engage gear teeth 26 of idler gear 20a. Gear teeth 26a of idler gear 20a in turn engage gear teeth 26b of idler gear 20b. Idler gears 20c, 20d, 20f and 20g engage neighbering idler gears in a manner similar to that described with reference to idler gears a and b. This arrangement, produces a gear train which causes second tool gear 48 to rotate. If an odd number of idler gears are employed, the rotation of second tool gear 48 will be in the same direction as first tool gear 46. 
     Each idler gear 20 preferably includes a coaxial shaft 54 which may be press-fit into a shaft or receiving hole 56 in idler gear 20, as best shown in FIG. 5. Upper housing portion 6a and lower housing portion 8a each include a plurality of shaft receiving holes 58 which are centered relative to each idler recess 30. The torque transmitting device T is assembled as follows: coaxial shafts 54 are press-fit into respective idler gears 20; each idler gear 20 is then positioned within respective idler gear recess 30 so that coaxial shaft 54 is received by shaft receiving hole 56; next, first tool gear 46 is positioned within recess 50 and second tool gear 48 is positioned within recess 52; housing portion 8a is then mated with housing portion 6a so that shafts 54 extend through shaft receiving holes 56 of housing portion 8a. Housing portion 8a may be fastened to housing portion 6a by means of screws, bolts, welds or the like. 
     FIGS. 6, 7, 9, 10 and 11 
     A second embodiment of the invention includes disk or gear member 60, lower housing portion 6b, upper housing portion 8b, first tool gear 46 and second tool gear 48. First tool gear 46 and second tool gear 48 are identical to tool gears 46 and 48 discussed above. 
     Gear member 60 includes a gear part 62 and a disk part 64. Disk part 64 forms an annular peripheral bearing surface 68 having a width approximately one-half of the width of gear disk member 60. Gear part 62 has a flat top surface with gear teeth 70 formed about the periphery of the top part. The depth of the gear part and depth of the gear teeth is approximately equal to the width of the disk part 64. The outermost portion of the gear teeth define an outer gear tooth perimeter which is substantially the same as the perimeter of the annular peripheral bearing surface 68. 
     Housing parts 6b and 8b are best shown in FIGS. 10 and 11 respectively. Housing part 6b includes outer recesses or first and second tool gear recesses 72 and 74. Between outer gear recesses 72 and 74 there are preferably an odd number of idler gear recesses 76a through 76g. An odd number of idler gear recesses is preferred so that, when gear member 60 and tool gear members 46 and 48 are placed within the housing, the rotation of first tool gear 46 will cause a rotation of second tool gear 48 in the same direction as first tool gear 46. Tool recesses 76a through g are formed with a diameter slightly larger than the diameter of disk part 64. Idler gear recesses 76a through 76g overlap one another and are preferably of two different depths. For example, recess 76a, adjacent tool gear recess 72, may be of a first depth substantially equal to the depth of tool gear recess 72 and overlap gear recess 72 a distance substantially equal to the length of gear tooth 70. Idler gear recess 76b, adjacent idler tooth gear recess 76a, may have a depth shallower than the depth of idler tooth gear recess 76a by a distance equal to the width of disk part 64. Idler tooth gear recesses 76d, 76e, 76f and 76g alternate in a similar fashion between recesses having a depth equal to the depth of recess A and recesses with a second depth equal to recess B. For instance, in FIG. 10, recesses 76c, 76e, and 76g are of the same depth as recess 76a and recesses 76d and 76f are of the same depth as recess 76b. 
     Housing portion 8b is similar to housing 6b in that there are two tool gear recesses 78 and 80 and an odd number of idler gear recesses 82a through 82g. However, the depth of idler tooth gear recesses 82a through 82g alternative in a manner which is just the opposite of the idler gear recesses of housing part 6b. For example, idler gear recess 82a has a depth which is shallower than that of adjacent tool gear recess 78 by a distance equal to the width of disk part 64. Idler gear recess 82b overlaps idler gear recess 82a and has a depth equal to the depth of tool gear recess 78. Idler gear recess 82c, 82e, and 82g each have a depth substantially the same as idler gear recess 82a. Idler gear recesses 82d and f have a depth substantially the same as idler gear recess 82b. 
     The device is assembled by press-fitting shaft 54 into a shaft receiving hole 86 formed in each of the idler gear members 60. The idler gear member 60 and associated coaxial shaft 54 are then positioned within housing parts 8b in respective idler gear recesses 82a through g. For example, a first idler gear 88 may be positioned within idler gear recess 82a so that gear part 62 of the idler gear 88 is adjacent the base of idler gear recess 82a. A second idler gear 90 may be positioned within idler gear recess 82b so that the disk part 64 of idler gear 90 lies adjacent the base of idler gear recess 82b. In this manner, the idler gears 60 are positioned within housing portion 8b so that they alternate between having gear part 62 set adjacent the base portion of the recess and having the disk part 64 adjacent the base of the recess of housing part 8b. Tool gears 46 and 48 are positioned within tool gear recesses 78 and 80 respectively. Housing part 6b is then joint with housing part 8b so that first tool gear 46, second tool gear 48 and idler gear 60 are each confined to associated gear recesses within housing parts 8b and 6b. 
     While this invention has been described as having preferred design, it is understood that it is capable of further modification, uses and/or adaptations of the invention following in general the principle of the invention and including such departures from the present disclosure as come within known or customary practice in the art to which the invention pertains, and as may be applied to the essential features set forth, and fall within the scope of the invention of the limits of the appended claims.