Abstract:
A torque tool having a visible indicator indicating that a predetermined number of usages of the torque tool has occurred. The indicator is carried on a movable platform which is moved into alignment with a window in the housing of the torque tool by a gearing assembly ultimately driven by a torque shaft for applying torque to a fastener. The gearing assembly includes gears extending along less than the full extent of the gear, so that a point is reached wherein at least one of the gears disengages from another gear, such that further rotation of the last gear does not occur. The indicator is eventually displayed to signal exhaustion of permissible usages, but is not moved further to conceal the indicator by disengagement of at least one gear from another.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 61/889,781, filed Oct. 11, 2013, which is hereby explicitly incorporated herein by reference. 
     
    
     FIELD OF THE DISCLOSURE 
       [0002]    The present disclosure relates to torque tools, and more particularly, to a torque tool having an ability to display information pertaining to a number of performed uses of the torque tool. 
       BACKGROUND 
       [0003]    Inexpensive torque tools provide a practical way of assembling devices needing applied torque to be measured or limited. Inexpensive torque tools may have a limited useful life after which they do not work, or alternatively, become objectionably inaccurate. 
       SUMMARY 
       [0004]    There is disclosed herein a torque tool which addresses the above stated situation by providing an ability to display an advisory message operable to indicated that the torque tool has attained a maximum number of performed uses, to prevent users from relying on the torque tool after its accuracy has been exhausted. 
         [0005]    To this end, the tool incorporates apparatus connected to a rotatable torque shaft which delivers torques to be applied to workpieces. The apparatus displays the advisory message after a predetermined maximum number of performed uses of the torque tool has been attained. The apparatus includes gearing which rotates a platform into view, the platform displaying the advisory message after a predetermined amount of rotation. 
         [0006]    The advisory message may include a final advisory that the predetermined maximum number of performed uses has occurred, or alternatively may also include at least one intermediate advisory indicating approach of the point at which the predetermined maximum number of performed uses has occurred. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Various objects, features, and attendant advantages of the present disclosure will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
           [0008]      FIG. 1  is a perspective view of a torque tool, according to at least one aspect of the disclosure; 
           [0009]      FIG. 2  is an exploded perspective view of the torque tool of  FIG. 1 , but fitted with a cap different from that illustrated in  FIG. 1 , according to at least one aspect of the disclosure; 
           [0010]      FIG. 3  is a bottom plan view of the uppermost component illustrated in  FIG. 2 ; 
           [0011]      FIG. 4  is an exploded perspective view of components housed within a body and a handle of the tool of  FIG. 1 ; and 
           [0012]      FIG. 5  is an enlarged plan detail view showing some components seen at the center of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    Referring first to  FIG. 1 , according to at least one aspect of the disclosure, there is shown a hand held torque tool  100  having a torque shaft  106  for applying a predetermined torque to an object (not shown), torque tool  100  having a predetermined usable service life. A predetermined useful service life will likely be necessitated by economics where torque tool is built for a limited number of usages, for example, where limited use, disposable tools displace tools intended for longer term use. Torque tool  100  comprises torque shaft  106  and torque limiting components acting on torque shaft  106  to limit torque applied thereby, and a use limiter discouraging torque tool  100  from being used after the predetermined usable service life has expired. Torque tool  100  further comprises a body  102  and a handle  104  collectively containing the torque limiting components and the use limiter. Torque shaft  106  projects from body  102 . Body  102  and handle  104  enclose and protect the torque limiting components and the use limiter against incidental damage. As will become apparent hereinafter, handle  104  encloses functional components of torque tool  100  just as does body  102 . 
         [0014]      FIG. 2  shows functional components contained within handle  104 . A structural support platform  108  may be fastened to a lower handle member  110  by bolts  112  which may be driven into bosses  113 , the bolts  112  passing through holes  114  in ears  116  of structural support platform  108 . Structural support platform  108  includes an opening  118  for passing an extension shaft  120  of torque limiting components (see  FIG. 4 ). Torque limiting components are shown in  FIG. 4 . 
         [0015]    In  FIG. 4 , the torque limiting components act on both extension shaft  120 , which provides inputs for the use limiter, and also to limit torque applied to a drive shaft  121 . The drive shaft  121  drives objects such as fasteners (not shown) to a specified torque value. As illustrated, distal end  125  of drive shaft  121  may bear drive elements, such as a star shaped bit, as manufactured by Torx®. The torque limiting components limit the amount of torque imparted to extension shaft  120  and drive shaft  121 . 
         [0016]    Torque limiting components for drive shaft  121  include a first member  117  having upwardly projecting teeth  123  (upwardly projecting as seen in  FIG. 4 ), each tooth  123  including a ramp arranged at a small angle to a hypothetical plane perpendicular to extension shaft  120 . The small angle may be for example five to thirty degrees from the hypothetical plane. First member  117  is fixed to body  102 . 
         [0017]    First member  117  has an opposed second member  127  bearing teeth  129 . Teeth  129  are arranged in a complementary manner, interfitting with teeth  123  similar to teeth  129  but being opposite in pitch. When first and second members  117  and  127  are mutually rotated about an axis such as the rotational axis of extension shaft  120 , in one direction, they will mutually repel or displace one another as the opposed ramps of teeth  123  and  129  slide across one another. Rotation of first member  117  rotates second member  127  until mutually displaced to the point that the apices of teeth  123  and  129  slide past each other. A spring  131  adjustably varies resistance to mutual displacement of first and second members  117  and  127 , thereby varying the maximum torque which can be transmitted to second member  127  from first member  117 . A threaded plug  133  is adjusted by engagement of its hexagonal central aperture  135  by a wrench (not shown) to adjust resistance of spring  131 . Threads  137  of threaded plug  133  engage threads  139  of body  102 . Torque imparted to extension shaft  120  is thereby limited. 
         [0018]    Drive shaft  121  is limited as to imparted torque by a similar arrangement as that of extension shaft  120 , except that orientation of components and direction of action are reversed, since drive shaft  121  faces a direction opposite that of extension shaft  120 . First member  117  bears second teeth  151  (not visible, but structurally the counterparts of teeth  123 ) which face downwardly and interact with teeth  143  of third member  145 . Third member  145  has a hexagonal central aperture  147  which cooperates closely with a hexagonal outer surface  149  of drive shaft  121 . Consequently, third member  145  and drive shaft  121  rotate in tandem. Teeth  143  interact with teeth  151  in a manner similar to that of teeth  123  and  129 . A spring  153  biases third member  145  along drive shaft  121  against first member  117 . Mutual repulsion of first member  117  and third member  145  limits the amount of torque which can be imparted to drive shaft  121  by rotating body  102  (recalling that first member  117  is fixed to body  102 ). The maximum torque value is calibrated by determining position of body  117  along body  102  prior to fixing body  117  to body  102 . 
         [0019]    The use limiter comprises a visual indicator displaying advisory information indicating that the predetermined usable service life has expired. Without the visual indicator, users would be obliged to remember or otherwise track usages of torque tool  100 . Torque tool  100  further comprises a usage monitoring arrangement which causes the advisory information indicating that the predetermined usable service life has expired to be displayed responsive to rotation of torque shaft  106 . Rotations of torque shaft  106  are the true measure of uses. Hence basing the advisory information on rotations of torque shaft  106  provides a true indication of usages. 
         [0020]    Torque tool  100  further comprises a gearing assembly comprising a central drive gear  128  rotated by rotation of torque shaft  106 . Central drive gear  128  has gear teeth  129  (see  FIG. 5 ) occupying less than the full extent of the circumference  131  of central drive gear  128 . Torque tool  100  comprises a driven gear  132  having an internally facing surface  133  bearing teeth  135  along less than the full extent of internally facing surface  133 . At least one idler gear  124  is located between central drive gear  128  and driven gear  132 . The at least one idler gear  124  is configured to transmit rotation from central drive gear  128  to driven gear  132 . Continued rotation of central drive gear  128  ceases to rotate driven gear  132  when gear teeth  129  of central drive gear  128  pass the point of engagement with the at least one idler gear  124 . 
         [0021]    The visual indicator is moved by driven gear  132  when driven gear  132  is being rotated from central drive gear  128  when gear teeth  129  of central drive gear  128  engage the at least one idle gear  124 , and gear teeth  135  of driven gear  132  engage the at least one idler gear  124 . 
         [0022]    The visual indicator is not moved by driven gear  132  when gear teeth  129  of central drive gear  128  pass the point of engagement with the at least one idler gear  124  or when gear teeth  135  of driven gear  132  pass the point of engagement with the at least one idler gear  124 . 
         [0023]    The gearing assembly thereby actuates the visual indicator, and also causes the visual indicator to accurately reflect a use or usages of torque tool  100 . 
         [0024]    The usage monitoring arrangement comprises a window  138  in at least one of body  102  and handle  104 . A cap or platform  134  bears indicia  136  corresponding to the advisory information. Platform  134  bearing indicia  136  is moved into alignment with window  138  such that indicia  136  is visible from the exterior of torque tool  100  through window  138 , responsive to rotation of driven gear  132 . Window  138  enables indicia  136  to be visible, with the visual indicator being protected within body  102  or handle  104 . 
         [0025]    The gearing assembly and its operation will be described in greater detail below. Bosses  122  projecting from structural support platform  108  rotatably support idler gears  124 . Bosses  122  may serve as axles which occupy central throughbores  126  in idler gears  124  in close cooperation therewith, or alternatively, may receive fasteners (not shown) such as threaded fasteners which may be passed through central throughbores  126 . If provided, the fasteners serve as axles about which idler gears  126  rotate. 
         [0026]    Referring also to  FIG. 3 , a central drive gear  128  having a central opening  130  configured to receive and be rotated by extension shaft  120  engages idler gears  124 . In  FIG. 3 , it will be seen that idler gears  124  transmit rotation from central drive gear  128  to a driven gear  132 . As seen in  FIG. 2 , platform  134  is configured to snugly encircle and engage driven gear  132 . Platform  134  bears indicia  136 . Rotation of extension shaft  120  rotates central drive gear  128 . As will be further explained hereinafter, this rotation is transmitted to driven gear  132  via idler gears  124 , which then rotates platform  134 . 
         [0027]    Indicia  136  is visible through window  138  formed in an upper section  140  of handle  104 . Indicia  136  provides a warning to the user of torque tool  100  that torque tool  100  has reached the end of its predetermined usable service life, and should be discarded and/or replaced. Indicia  136  may comprise a legend, such as “Discard” (as illustrated in  FIG. 2 ), or “Do not use”. Instead of or in addition to a legend, indicia  136  may comprise a color scheme. Illustratively, a displayed portion of platform  134  may initially be colored black (indicating that torque tool  100  is new), with a transition to white (indicating that torque tool  100  is exhausted). Alternatively, gray coloring may be interposed between the white and the black to signal transition from new to exhausted. As a further alternative, other colors may be employed. Illustratively, yellow may be used to indicate that there are a predetermined number of cycles of use remaining, with red conveying a “Do not use” message. Indicia  136 , platform  134 , and window  138  collectively form the visual indicator to advise the user that the predetermined usable service life has expired. 
         [0028]    Referring also to  FIG. 5 , rotation of extension shaft  120  results in rotation of central drive gear  128 , idler gears  124  (only one idler gear  124  is shown in  FIG. 5 ), and driven gear  132 . It may be seen from  FIG. 56  that as there are only two teeth  129  on central drive gear  128 , one full rotation of the latter rotates idler gear  124  and hence driven gear  132  less than one full rotation each. Also, as idler gear  124  continues to rotate, it will disengage from driven gear  132  when teeth  135  pass the point of engagement with the teeth of idler gear  124 . Hence, driven gear  132  and its associated platform  134  bearing indicia  136  cease to rotate at a point. The gearing assembly is calibrated such that this point occurs with the last permissible usage of torque tool  100  having been performed. Following such calibration, platform  134  may be glued to driven gear  132 . 
         [0029]    With the number of teeth  129  of central drive gear  128  being only one or two the advancement of platform  134  would be only one or two teeth  135  with each full three hundred sixty degrees of rotation of central drive gear  128 . If it is desired to increase the number of teeth of advancement of the driven gear  132 , e.g., to reduce the number of useable cycles of torque tool  100 , additional teeth  129  can be added to central drive gear  128  to increase advancement with each full rotation of extension shaft  120 . Driven gear  132  has a limited number of teeth  135  so driven gear  132  will only rotate a specified angle of rotation. Additional teeth  135  provide more cycles of count of useful life of torque tool  100 . 
         [0030]    Driven gear  132  may be constrained against spontaneous rotation when its teeth  135  do not engage idler gears  124 . This may be accomplished by a coil spring (not shown) engaging driven gear  132  or platform  134 , or by any other suitable source of friction opposing spontaneous rotation of driven gear  132 . 
         [0031]    Referring again to  FIG. 1 , torque tool  100  may further comprise a lens  142  in window  138 , lens  144  magnifying indicia  136 . Because indicia  136  may comprise very small lettering where indicia  136  comprises a legend, lens  144  may make reading the legend easier. 
         [0032]    Unless otherwise indicated, the terms “first”, “second”, etc., are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the times to which these terms refer. Moreover, reference to, e.g., a “second” item does not either require or preclude the existence of, e.g., a “first” or lower-numbered item, and/or, e.g., a “third” or higher-numbered item. 
         [0033]    It should be understood that the various examples of the apparatus(es) disclosed herein may include any of the components, features, and functionalities of any of the other examples of the apparatus(es) disclosed herein in any feasible combination, and all of such possibilities are intended to be within the spirit and scope of the present disclosure. Many modifications of examples set forth herein will come to mind to one skilled in the art to which the present disclosure pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. 
         [0034]    Therefore, it is to be understood that the present disclosure is not to be limited to the specific examples presented and that modifications and other examples are intended to be included within the scope of the appended claims. Moreover, although the foregoing description and the associated drawings describe examples of the present disclosure in the context of certain illustrative combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative implementations without departing from the scope of the appended claims.