Abstract:
A lockable torque-limiting driver that includes, a body, a sleeve, a shaft carried by the body for rotation relative thereto and having a fastener-engaging tip at one end that projects from the body, a torque-limiting mechanism coupled to the shaft and housed within said body, a torque-adjusting mechanism within the body and coupled to the torque-limiting mechanism for adjusting the torque-limiting mechanism to a desired torque value, a torque-locking mechanism operably coupled with the torque-adjusting mechanism and the body or the sleeve for preventing movement of the torque-determining means and locking the settable torque-limiting driver at the desired torque value.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of the filing date under 35 USC 119(e) of the filing date of U.S. Provisional Application Ser. No. 60/674,785, filed Apr. 26, 2005. 
     
    
     BACKGROUND  
       [0002]     This application relates generally to driving tools such as screwdrivers, nut drivers, bolt drivers, wrenches and the like wherein the amount of torque that the tool can apply to a given fastener is limited to a settable value. More specifically, this application relates to a torque locking mechanism usable in said tools that allows a fine range of torques for a given tool and prevents the inadvertent change of the torque setting once set.  
         [0003]     Torque settable drivers as described above are well known in the art. This application relates to drivers that are designed for specific uses and thus a lockable torque value is desirable. The need for a lockable torque-limiting driver that can drive a given fastener at a desired torque value is useful in a variety of fields including sporting goods, electronics and computer assembly, and any other use wherein specific tolerances are required. However, it would be desirable if there was a tool that would allow for a fine range of torque setting such that a given tool could be effectively locked into a variety of specific torque settings. It would also be desirable for such a tool to be low-cost and suitable for mass production without sacrificing precision.  
       SUMMARY  
       [0004]     This application discloses a settable torque-limiting driver that is economical to produce, of simple construction and capable of mass production, but also capable of being locked in a variety of precise torque settings.  
         [0005]     In particular, this application discloses a lockable torque-limiting driver that includes gripping means, a body, a sleeve, a shaft carried by the body for rotation relative thereto and having a fastener-engaging tip at one end that projects from the body, torque-limiting means coupled to said shaft and housed within said body, torque-adjusting means within said body and coupled to said torque-limiting means for adjusting the torque-limiting means to a desired torque value, torque-locking means operably coupled with said torque-adjusting means and said body for preventing movement of said torque-determining means and locking the settable torque-limiting driver at the desired torque value.  
         [0006]     In another embodiment, this application discloses a lockable torque-limiting driver that includes gripping means, a body, a sleeve, a shaft carried by the body for rotation relative thereto and having a fastener-engaging tip at one end that projects from the body, torque-limiting means coupled to said shaft and housed within said body, torque-adjusting means within said body and coupled to said torque-limiting means for adjusting the torque-limiting means to a desired torque value, torque-locking means operably coupled with said torque-adjusting means and said sleeve for preventing movement of said torque-determining means and locking the settable torque-limiting driver at the desired torque value.  
         [0007]     In a further embodiment, this application discloses a method for locking a settable torque-limiting driver at a desired torque value by providing a torque-limiting mechanism coupled to a shaft and housed within a body, setting a torque-adjusting mechanism coupled to said torque-limiting mechanism, and engaging the torque-adjusting mechanism with a torque-locking mechanism.  
         [0008]     In yet a further embodiment, this application discloses a golf club weight attachment system comprising: a golf club capable of being adjusted by securing screwably attachable weights in defined positions at a desired torque setting on said club; and, a lockable torque-limiting driver for securing said weights to said golf club at a defined torque setting wherein the driver comprises a body; a sleeve carried by said body; a shaft carried by said body for rotation relative thereto and having a weight-engaging tip at one end that projects from the body for screwably attaching said weights; torque-limiting means coupled to said shaft and housed within said body; torque-adjusting means within said body and coupled to said torque-limiting means for adjusting the torque-limiting means to the desired torque value; and, torque-locking means operably coupled with said torque-adjusting means and said body or said sleeve for preventing movement of said torque-determining means and locking the settable torque-limiting driver at the desired torque value such that the weights are attached to the golf club at the desired torque value.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The drawings, when considered in connection with the following description, are presented for the purpose of facilitating an understanding of the subject matter sought to be protected.  
         [0010]      FIG. 1A  is a front elevational view of a lockable torque-limiting driver;  
         [0011]      FIG. 1B  is a sectional view of the driver taken generally along the line  1 B- 1 B in  FIG. 1A  showing a first embodiment of the locking mechanism;  
         [0012]      FIG. 1C  is an exploded view of the driver of  FIG. 1A ;  
         [0013]      FIG. 2A  is a front elevational view of a lockable torque-limiting driver;  
         [0014]      FIG. 2B  is a sectional view of the driver taken generally along the line  2 B- 2 B in  FIG. 2A  showing a second embodiment of the locking mechanism;  
         [0015]      FIG. 2C  is an exploded view of the driver of  FIG. 2A ;  
         [0016]      FIG. 3A  is a front elevational view of a lockable torque-limiting driver;  
         [0017]      FIG. 3B  is a sectional view of the driver taken generally along the line  3 B- 3 B in  FIG. 3A  showing a third embodiment of the locking mechanism;  
         [0018]      FIG. 3C  is an exploded view of the driver of  FIG. 3A ;  
         [0019]      FIG. 4  is a 90° side elevational view of the driver of  FIG. 1A ;  
         [0020]      FIG. 5  is a sectional view of the driver showing the first embodiment of the locking mechanism of  FIG. 1B  taken generally along the line  5 - 5  in  FIG. 4 ;  
         [0021]      FIG. 6  is a perspective view of the rotational cam of  FIGS. 1C, 2C , and  3 C;  
         [0022]      FIG. 7  is a perspective view of the non-rotational cam of  FIGS. 1C, 2C , and  3 C;  
         [0023]      FIG. 8  is perspective view of the sleeve of  FIGS. 1C and 2C ;  
         [0024]      FIG. 9A  is a top plan view of the sleeve in  FIG. 8 ;  
         [0025]      FIG. 9B  is a side elevational view of the sleeve in  FIG. 8 ;  
         [0026]      FIG. 9C  is a 90° side elevational view of the sleeve in  FIG. 9B ;  
         [0027]      FIG. 9D  is a sectional view of the sleeve taken generally along the line  9 D- 9 D in  FIG. 9C ;  
         [0028]      FIG. 10  is perspective view of the sleeve of  FIG. 3C ;  
         [0029]      FIG. 11A  is a top plan view of the sleeve in  FIG. 10 ;  
         [0030]      FIG. 11B  is a side elevational view of the sleeve in  FIG. 10 ;  
         [0031]      FIG. 11C  is a 90° side elevational view of the sleeve in  FIG. 11B ;  
         [0032]      FIG. 11D  is a sectional view of the sleeve taken generally along the line  11 D- 11 D in  FIG. 11C ;  
         [0033]      FIG. 12  is a top plan view of the generally circular member of the body of the driver of  FIGS. 1C and 2C , isolated to show its details;  
         [0034]      FIG. 13  is a perspective view of the adjustment plug of  FIG. 1C ;  
         [0035]      FIG. 13A  is an additional perspective view of the adjustment plug of  FIG. 1C ;  
         [0036]      FIG. 13B  is a top plan view of the adjustment plug of  FIG. 1C ;  
         [0037]      FIG. 13C  is a side elevational view of the adjustment plug of  FIG. 1C ;  
         [0038]      FIG. 13D  is a 90° side elevational view of the adjustment plug of  FIG. 13C ;  
         [0039]      FIG. 14  is a perspective view of the locking plate of  FIG. 1C ;  
         [0040]      FIG. 14A  is an additional perspective view of the locking plate of  FIG. 1C ;  
         [0041]      FIG. 14B  is a top plan view of the locking plate of  FIG. 1C ;  
         [0042]      FIG. 14C  is a side elevational view of the locking plate of  FIG. 1C ;  
         [0043]      FIG. 14D  is a 90° side elevational view of the locking plate of  FIG. 14C ;  
         [0044]      FIG. 15  is a perspective view showing the coupling of the adjustment plug and locking plate of the driver of  FIG. 1B ;  
         [0045]      FIG. 16  is a perspective view of the locking mechanism of the driver of  FIG. 1B ;  
         [0046]      FIG. 17  is a fragmentary sectional view along the line similar to the view in  FIG. 5  showing the second embodiment of the locking mechanism of the driver of  2 B;  
         [0047]      FIG. 18  is a perspective view showing the adjustment plug of the driver of  FIGS. 3B and 3C ;  
         [0048]      FIG. 18A  is an additional perspective view of the adjustment plug of  FIGS. 2C and 3C ;  
         [0049]      FIG. 18B  is a top plan view of the adjustment plug of  FIGS. 2C and 3C ;  
         [0050]      FIG. 18C  is a side elevational view of the adjustment plug of  FIGS. 2C and 3C ;  
         [0051]      FIG. 18D  is a 90° side elevational view of the adjustment plug of  FIG. 18C ;  
         [0052]      FIG. 19  is a perspective view showing the locking plate of the driver of  FIG. 2C ;  
         [0053]      FIG. 19A  is an additional perspective view of the locking plate of  FIG. 2C ;  
         [0054]      FIG. 19B  is a top plan view of the locking plate of  FIG. 2C ;  
         [0055]      FIG. 19C  is a side elevational view of the locking plate of  FIG. 2C ;  
         [0056]      FIG. 19D  is a 90° side elevational view of the locking plate of  FIG. 19C ;  
         [0057]      FIG. 19E  is a bottom plan view of the locking plate of  FIG. 2C ;  
         [0058]      FIG. 20  is a perspective view showing the coupling of the adjustment plug and locking plate of the driver of  FIG. 2B ;  
         [0059]      FIG. 21  is a perspective view showing the locking mechanism of the driver of  FIG. 2B ;  
         [0060]      FIG. 22  is a fragmentary sectional view along the line similar to the view in  FIG. 5  showing the third embodiment of the locking mechanism of the driver of  3 B;  
         [0061]      FIG. 23A  is an perspective view of the locking plate of  FIG. 3C ;  
         [0062]      FIG. 23B  is a top plan view of the locking plate of  FIG. 3C ;  
         [0063]      FIG. 23C  is a side elevational view of the locking plate of  FIG. 3C ;  
         [0064]      FIG. 23D  is a 90° side elevational view of the locking plate of  FIG. 23C ;  
         [0065]      FIG. 23E  is a bottom plan view of the locking plate of  FIG. 3C ;  
         [0066]      FIG. 24  is a perspective view showing the locking mechanism of the driver of  FIG. 3B ;  
         [0067]      FIG. 25  is an additional embodiment of the driver of  FIG. 24  showing the locking mechanism of the driver of  FIG. 3B  used in a T-shaped driver;  
         [0068]      FIG. 26  is a sectional view of the driver in  FIG. 25 ; and,  
         [0069]      FIG. 27  is a perspective view showing a golf club weight attachment system.  
     
    
     DETAILED DESCRIPTION  
       [0070]     Referring to  FIGS. 1A-3C , shown therein and generally designated by the reference character  10  is a lockable toque-limiting driver constructed in accordance with the following description. The driver  10  includes a body  12  having an elongated shaft  14  with a fastener-engaging portion  16  extending from one end thereof. At the other end, the driver  10  is provided with a cap member  18 .  
         [0071]     As may be seen more clearly in  FIGS. 1B and 5 , the body  12  is comprised of a generally circular upper member  13  and a hollow, generally cylindrical stem portion  15  with a tapered hexagonal shaped in transverse cross section end wall  17  terminating at its end with axial bore  19  formed therethrough. The inner surface of circular member  13  is provided with a plurality of circumferentially spaced channels  20  ( FIG. 12 ).  
         [0072]     Referring to  FIG. 1B  and in particular  FIGS. 8-9D , the driver  10  includes a sleeve  21  having an elongated, hollow, generally cylindrical body  22  with circumferentially spaced outwardly projecting flanges  23  positioned to be received in the channels  20  ( FIG. 21 ). Formed along the inner surface of the sleeve  21 , at circumferentially spaced locations, is a plurality of longitudinally extending channels  24  ( FIGS. 9A and 9D ). The cylindrical body  22  has a tapered hexagonal shaped in transverse cross section end wall  25  with an axial bore  26  formed therethrough. The inner surface of sleeve  21  includes threads  27  at its upper and open end ( FIGS. 8 and 9 D). During assembly, sleeve  21  is coaxially received in the stem portion  15  of the driver, with hexagonally shaped sleeve end wall  25  mateably seated in the hexagonally shaped body end wall  17 , ( FIG. 1B ) and flanges  23  mateably received in the channels  20  ( FIGS. 1B and 21 ) thereby preventing rotation of sleeve  21  relative to body  12 .  
         [0073]     As shown in  FIGS. 2C and 5 , the driver  10  includes an elongated shaft  14  with a fastener-engaging portion  16  at one end. The shaft portion above the engaging portion is hexagonal shaped in transverse cross section. Intermediate to its ends, shaft  14  includes a circumferential groove  30 , operably configured to receive a retaining ring  31  ( FIGS. 2C and 5 ). At the end opposite of the fastener-engaging portion  16 , the shaft  14  includes a bearing end face  32  configured for engagement with a ball bearing  33 . During assembly, the shaft  14  is passed through aligned bores  19  and  26  in the driver stem  15  and sleeve  21  respectively, with the retaining ring  31  seated on the inner surface of sleeve end wall  25  ( FIG. 5 ).  
         [0074]     Referring to  FIGS. 5-7 , the driver  10  includes torque-limiting means, which may comprise an upper non-rotational cam  40 , a lower rotational cam  41 , and a compression spring  42 . More particularly, upper cam  40  includes an annular body  43  and a cylindrical bore  44  formed axially therethrough. On the outer surface of annular body  43  are circumferentially spaced outwardly projecting splines  45 . The upper cam  40  has an upper face  48  and a lower face comprised of circumferentially spaced teeth  45 , each having a sloping face  46  and an axial face  47 . The lower cam  41  includes an elongated cylindrical portion  49  at one end and an elongated location boss portion  50  at the other. Intermediate and integral with the two portions  49  and  50  is a radially extending annular body  51  that includes a lower face  52  and an upper face comprised of circumferentially spaced teeth  53 , each having a sloping face  54  and an axial face  55 . A hexagonal bore  56  dimensioned to mateably receive shaft  14  is formed through the lower cam  41 .  
         [0075]     Referring to  FIGS. 2B, 2C  and  5 , during assembly, the lower cam  41  is fitted over the shaft  14  within the sleeve  21  with the lower face  52  seated on a thrust washer  57 , which is seated on the sleeve wall  28 . When assembled, the hexagonal bore  56  acts in concert with the hexagonal shaft  14  to prevent rotation of the shaft  14  relative to lower cam  41 . The upper cam  40  is then fitted down coaxially over the upper end of shaft  14  and within sleeve  21  such that the outwardly projecting splines  45  are mateably received by the longitudinal channels  24  on the inner surface of the sleeve ( FIGS. 8A and 9D ) and the teeth  45  of the upper cam are mateably engaged with the teeth  53  of the lower cam  41 . In such an orientation, the upper cam  40  is prevented from rotation relative to the sleeve  21 . And the relative rotation of the upper and lower cams  40  and  41  is prevented in one direction due to the engagement of the axial faces  47  of the teeth  45  with the axial faces  55  of the teeth  53  of the of the upper and lower cams respectively. However, relative rotation of the upper and lower cams  40  and  41  is provided in the opposite direction due to the engagement of the sloping faces  46  of the teeth  45  with the sloping faces  54  of the teeth  53  of the upper and lower cams respectively. Lastly, the torque-limiting means is completed by coaxially fitting the compression spring  42  over the upper end of the shaft  14 , within the sleeve  21 , and seated on the upper face  48  of the upper cam  40 .  
         [0076]     The driver  10  includes a torque-adjustment means, which comprises an annular adjustment plug. Two embodiments are described. The first embodiment is shown in  FIGS. 1B and 1C , and in particular  FIGS. 13-13D . Here the adjustment plug  60  has an annular body  61  with an externally threaded surface  62 , a lower end face  63 , an upper end face  64  and a cylindrical axial bore  65  therethrough. The upper end face  64  is further characterized by an elongated key structure  66 , in this embodiment, a twelve point star formation. The second embodiment of the adjustment plug is shown in  FIGS. 2B, 17  and in particular  FIGS. 18-18D . Here the adjustment plug  67  has an annular body  68  with an externally threaded surface  69 , a lower end face  70 , an upper end face  71 , and a keyway structure  72  therethrough, in this embodiment, an octagonal bore. During assembly, the adjustment plug  60  or  67  is fitted coaxially over the upper end of the shaft  14 , and threadedly engaged in the upper open end of the sleeve  21 , for bearing against the upper end of the compression spring  42 . The extent to which the adjustment plug  60  or  67  is threaded into the sleeve  21  controls the amount of compression on the spring  42 , which, in turn, controls the force with which the upper cam  40  is driven into engagement with the lower cam  41 . Thus, the limiting torque required to effect the relative rotation of the upper and lower cam can be set to a desired torque value. To effect the threading of the adjustment plug to the desired position, a socket wrench or the like can be used to engage the key or keyway structure,  66  and  72  respectively.  
         [0077]     To maintain the desired torque value, the driver  10  includes a torque-locking means, which comprises a locking plate coupled with the adjustment plug and the driver body to prevent the inadvertent movement of the adjustment plug. Again, two embodiments of the locking plate are described to coincide respectively with the two previously described adjustment plug embodiments. The first embodiment is shown in  FIGS. 1B, 5  and in particular  FIGS. 14-14D . The locking plate  75  has a generally diamond shape and includes an adjustment plug-engaging portion  76  and a body-engaging portion  77 . The plug-engaging portion  76  is characterized by a bored keyway structure  78 , in this embodiment, a twelve point star formation to mateably receive the adjustment plug  60  ( FIGS. 15 and 16 ). The body-engaging portion  77  is characterized by serrations  79  located at opposite ends of the plate  75 , in this embodiment, six serrations per end. The second embodiment of the locking plate is shown in  FIGS. 1B, 17 ,  21 , and in particular  FIGS. 19-19D . Here the locking plate  80  is generally T-shaped and includes an adjustment plug-engaging portion  81 , a body engaging portion  82 , and a cylindrical bore  83  formed axially therethrough. The plug-engaging portion  81  is characterized by an elongated key structure  84 , in this embodiment, a twelve point star formation to mateably receive the adjustment plug  67  ( FIGS. 17 and 20 ). The body-engaging portion  85  is characterized by serrations  86  located at opposite ends of the plate  80 , in this embodiment, six serrations per end. To receive the body-engaging portions of the locking plates  75  and  80 , the body  12  of the driver  10 , and in particular the upper surface of the generally circular upper member  13 , includes locking plate-engagement portions  89  ( FIG. 12 ). In the embodiment shown in  FIG. 12 , the locking plate-engagement portions  89  include serrations  87  which are shown integral with the cap location bores  88  to receive the body-engagement portions  77  and  82  respectively ( FIGS. 16 and 21 ). In  FIG. 12 , the locking plate-engagement serrations  87  are shown integral with only two of the cap location bores  88 , but it should be appreciated that the engagement serration may be associated with the other cap location bores for even finer adjusting and locking means.  
         [0078]     Referring to  FIGS. 1B, 1C  and  16 , during assembly of the first embodiment of the torque-locking means, locking plate  75  is fitted coaxially over the upper end of shaft  14 , the bored keyway structure  78  of the plug-engagement portion  76  is mateably received by the elongated key structure  66  of the adjustment plug  60 , and the serrations  79  of the body-engaging portion  77  are received by the locking plate-engagement serrations  87  of the upper generally circular member  13  such that the adjustment plug is locked in position. Referring to  FIGS. 2B, 2C ,  17  and  21 , during assembly of the second embodiment, the locking plate  80  is fitted coaxially over the upper end of the shaft  14 , the elongated key structure  84  of the plug-engagement portion  81  is mateably received by the keyway structure  72  of the adjustment plug  67 , and the serrations  86  of the body-engaging portion  85  are received by the locking plate-engagement serrations  87  of the upper generally circular member  13  such that the adjustment plug is locked in position.  
         [0079]     The preferred embodiment of the driver  10  is shown in  FIGS. 3A-3C . Referring to  FIGS. 3B and 3C , the driver includes a third embodiment of the torque-locking means which comprises a locking plate coupled with the adjustment plug and the sleeve to prevent the inadvertent movement of the adjustment plug. The third embodiment of the locking means utilizes the adjustment plug  67  previously shown in  FIGS. 2B, 17  and in particular  FIGS. 18-18D . To restate briefly, the adjustment plug  67  has an annular body  68  with an externally threaded surface  69 , a lower end face  70 , an upper end face  71 , and a keyway structure  72  therethrough, in this embodiment, an octagonal bore. Referring to  FIGS. 3B and 3C , during assembly, the adjustment plug  67  is fitted coaxially over the upper end of the shaft  14 , and threadedly engaged in the upper open end of the sleeve  29 , for bearing against the upper end of the compression spring  42 . Sleeve  29  is similar to the sleeve  21  previously described, but includes a pair of prongs  29 A located on opposite sides of the upper open end of the sleeve ( FIGS. 10-11D ). The locking plate utilized in the third embodiment of the torque-locking means is shown in  FIGS. 3B, 3C , and in particular  FIGS. 23A-23E . The locking plate  100  is generally gear shaped and includes an adjustment plug-engaging portion  101 , a sleeve engaging portion  102 , an annular cap-receiving portion  107 , and a cylindrical bore  103  formed axially therethrough. The plug-engaging portion  101  is characterized by an elongated key structure  104 , in this embodiment, an eight point star formation to mateably receive the adjustment plug  67  ( FIGS. 3B and 22 ). The sleeve-engaging portion  102  is characterized by gears  105  about its circumference with undulations  106  to mateably receive the locking plate-engagement portions  29 B, which include prongs  29 A on the upper end of the sleeve  29  ( FIG. 24 ).  
         [0080]     Referring to  FIGS. 3B, 3C ,  22  and  24 , during assembly of the third embodiment, the locking plate  100  is fitted coaxially over the upper end of the shaft  14 , the elongated key structure  104  of the plug-engagement portion  101  is mateably received by the keyway structure  72  of the adjustment plug  67 , and the undulations  106  of the sleeve-engaging portion  102  are received by the locking plate-engagement prongs  29 A on the upper end of the sleeve  29 such that the adjustment plug is locked in position.  
         [0081]     To complete the assembly of the driver  10 , a gripping means comprising a cap  18  with a grippable surface  95  and a cushion and/or label  96  ( FIGS. 1A and 1C ) is mounted to the generally circular member  13 . During assembly, a ball bearing  33  is seated in the ball support  91  of the cap  18  ( FIG. 17 ), and the cap is then fitted over the upper generally circular member  13 , to a mounted position shown in  FIGS. 5 and 17 . In the mounted position, the ball bearing  33  is held against the bearing end face  32  of the shaft  14  and the location posts  92  ( FIG. 17 ) are mateably received in the cap location bores  88  ( FIGS. 12 and 17 ). The cap may be snap-fitted to the generally circular member  13 , or fixed by sonic welding, solvent welding or the like. When the cap is fixed, the driver is permanently assembled with the torque setting locked in the desired position.  
         [0082]     Finally  FIG. 27  shows a golf club weight attachment system  100  whereby a lockable torque-limiting driver  10  is locked at a desired torque setting as described above is used with a weight adjustable golf club  101  (as well known in the art) with weights  102  that are screwably attached at locations  104  on the club  101 . The weights  102  are attached to the club  101  by inserting the weight-engaging tip  16 A of the shaft  14  into the weights  102  and then screwably attaching them at locations  104  (at the desired torque setting) so that the desired weight characteristics of the club are realized. See below for a detailed description of the operation of the driver  10 .  
         [0083]     Operation of the driver  10  is accomplished by the taking the cap  18  into the user&#39;s hand such that the palm rests on the upper surface of the cap and the fingers rest within the grippable surface  95 . In addition to the generally circular driver previously described, the driver  10  may also be substantially T-shaped, and example of which is shown in  FIGS. 25 and 26 . For the T-shaped embodiment, it will be appreciated that the inner workings are the same as previously described for the generally circular embodiment and, in operation, the arms  110  of the driver may be rested in the palm of the user&#39;s hand, with the fingers wrapped beneath the arms and straddling the stem potion  111 . When the driver in either embodiment is rotated in one direction, the shaft  14  will rotate with the body  12  until the desired torque level is reached, at which point the biasing force exerted by the spring  42  is overcome to allow the sloping faces  46  of the upper cam  40  to slide up the sloping faces  54  of the lower cam  41  for the angular distance of one tooth, at which point the upper cam  40  will snap into engagement behind the next tooth of the lower cam  41 , thereby provide the user a tactile and/or audible indication that the desired torque has been reached.  
         [0084]     In the construction of the driver  10 , a majority of the components may be formed of suitable plastics that may be molded, however, components that must withstand load bearing, torsional, and other significant forces such as the retaining ring  31 , spring  42 , shaft  14  and ball bearing  33  may be formed of suitable metals. Based on the forgoing description and accompanying figures, it can be seen that there has been provided an improved lockable torque-limiting driver that allows for a fine range of torque setting such that it can be effectively locked into a variety of specific torque settings. It has also been shown that the driver can be produced at a low-cost and is suitable for mass production without sacrificing precision.