Abstract:
A counting device includes a shaft, a handle affixed to a first end of the shaft, and a locking unit mounted in the handle spaced from the shaft. A locking plate has an opening for accommodating the shaft. The locking plate has a plurality of recesses facing the locking unit for cooperating with the locking unit. A position indicating assembly is coupled to the shaft to move as the handle is rotated. The recesses are arranged in a circular pattern on the locking plate such that the locking unit engages each recess as the handle is rotated around the shaft. The recesses are configured to permit one-way rotation of the handle.

Description:
BACKGROUND 
       [0001]    Many devices have a predetermined useful life based upon the number of times the device operates. These types of devices are typically discarded or refurbished after the predetermined number of uses occurs. The continued use of devices beyond the predetermined number of uses may lead to deteriorated performance, failure of the device, or may generate undesirable results. 
         [0002]    One example of a device that is retired or refurbished after a predetermined number of uses is a sterilization challenge specimen holder. A sterilization challenge specimen holder is used to hold a biological indicator during a sterilization cycle to provide a consistent challenge to sterilization. Examples of such holders are disclosed in Bala, U.S. Pat. Nos. 7,718,125; 7,740,802; 7,790,105; and 7,811,516, all of which are commonly assigned with the present application and are incorporated herein by reference. Due to concerns regarding thermal effects of cycling, after a specific number of uses, the performance of the sterilization specimen holder is assumed to be compromised. Accordingly, the holder must be refurbished or discarded after the predetermined number of uses has occurred. 
         [0003]    It is, however, difficult to track the number of times the holder is used to sterilize materials because the holder does not include a mechanism to count the number of uses. Further, requiring documentation of uses on an instrument separate from the holder can lead to errors in counting due to operators forgetting to record uses of the device. Based on these concerns, a need exists for a device that can be mounted directly to a holder that facilitates counting the number of times the holder has been used. 
       SUMMARY 
       [0004]    Various embodiments of the present disclosure include a mechanical counting device that includes a shaft, a handle affixed to a first end of the shaft and a locking unit on the handle spaced from the shaft. A locking plate has a central opening to accommodate the shaft and is spaced from the handle. 
         [0005]    The locking plate has a plurality of recesses therein facing the locking unit engagement unit. A position indicating assembly is rotatably coupled to the shaft, which moves longitudinally along the shaft as the handle is rotated. The recesses are arranged in a circular pattern on the locking plate such that the locking unit engages each recess as the handle is rotated around the shaft. The recesses are configured to permit one-way rotation of the handle. 
         [0006]    Other embodiments of the present disclosure include a method of counting the uses of a device via a counting device, and includes the steps of rotating a handle affixed to a first end of a shaft, the handle including a locking unit on the handle spaced from the shaft. A locking plate has an opening to accommodate the shaft and includes a plurality of recesses having entrance and exit portions. A position indicating assembly is rotatably coupled to the shaft and moves longitudinally along the shaft as the handle is rotated. The recesses are arranged in a circular pattern on the locking plate such that the locking unit engages each recess as the handle is rotated around the shaft. The recesses permitting only one-way rotation of the handle. 
         [0007]    Other objects, features, and advantages of the disclosure will be apparent from the following description, taken in conjunction with the accompanying sheets of drawings, wherein like numerals refer to like parts, elements, components, steps, and processes. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    FIG. I is an exploded view of a counter for a sterilization challenge specimen holder; 
           [0009]      FIG. 2  is a perspective view of a locking plate recess; 
           [0010]      FIGS. 3A-3D  illustrates a locking unit finger in and moving through a recess in the locking plate; and 
           [0011]      FIG. 4  illustrates a the counter of  FIG. 1  mounted to an exemplary sterilization challenge specimen holder. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    While the present disclosure is susceptible of embodiment in various forms, there is shown in the drawings and will hereinafter be described one or more embodiments with the understanding that the present disclosure is to be considered illustrative only and is not intended to limit the disclosure to any specific embodiment described or illustrated. 
         [0013]      FIG. 1  is an exploded view of a sterilization challenge specimen holder counter  100 . The counter  100  includes a handle  102  having an opening  302  that is sized to accommodate a threaded shaft or post  104 , a locking plate  106 , and a position indicator assembly  108 . The shaft  104  may be a bolt, a screw, a threaded rod, or any other device capable of connecting the handle  102  to the position indicator assembly  108 . The shaft  104  and handle  102  are fixed mounted to one another so that rotation of the handle  102  results in rotation of the shaft  104 . In a present embodiment, the shaft  104  is formed as a bolt, and a lock washer  105  is positioned between the head  502  of the bolt and the handle  102 . 
         [0014]    The shaft  104  passes through an opening  202  in the center of the locking plate  106 . The locking plate  106  includes a plurality of locking recesses  206 , described in more detail below, formed in the locking plate  106  facing the handle  102 . The recesses  206  are sized to cooperate with a biased locking unit  112  on the handle  102  to permit the handle  102  to be rotated in one direction (a forward direction), but to prevent rotation in the opposite direction (a rearward or backward direction). The handle  102  is separated from the locking plate  106  by a spacing unit  114  having an opening sized to accommodate the shaft  104 . 
         [0015]    The position indicator assembly  108  includes a central plate  116  having a threaded opening  117  that is sized to threadedly mate with the shaft  104 , and an indicator  118  that extends from an edge of the plate  116 . A locking ring  120  is positioned on the shaft  104  adjacent to the plate  106 , between the plate  106  and the position indicator assembly  108 . The locking ring  120  is secured to the shaft  104 , by, for example, set screws  121 , to prevent the locking plate  106  and shaft  104  from longitudinally moving relative to one another (as when the handle  102 /shaft  104  are rotated). 
         [0016]    It will be appreciated that absent the locking unit  112 , as the handle  102  and shaft  104  are rotated, the plate  116  which is threadedly engaged with the shaft  104 , will move along the shaft  104 . As such, the location of the plate  106  along the shaft  104  will correlate to the number of turns of the shaft  104 . 
         [0017]    The locking plate  106 , in conjunction with the locking unit  112  and handle  102 , permit only one-way rotation of the shaft  104 . The plate  106  is substantially circular, and includes a central opening  202  through which the shaft  104  passes, at least two securing openings  204 , and the recesses  206 . The recesses  206  are arranged along a circular path on the locking plate  106  a distance so as to cooperate with the locking unit  112 . 
         [0018]    The locking unit  112  includes a cap  309 , a spring  310 , a collar  312 , and an engaging finger  314 . The finger  314  is positioned in the collar  312  such that a lower portion of the finger  314  is secured by and extends beyond an end of the collar  312  (see, e.g.,  FIG. 3A ). The upper portion of the finger  314  is coupled to a spring  310  which biases the finger  314  out of the handle  102 . A force applied on the finger  314  against the bias or spring  310  urges the finger  314  into the handle  102 . 
         [0019]      FIG. 2  is a perspective view of one of the recesses  206  in the locking plate  106 . As set forth above, the locking unit  112 , in conjunction with the locking plate  106  and recesses  206  allow one-way rotation of the handle  102  relative to the plate  106 . Accordingly, each recess  206  includes an entrance portion  208  and an exit portion  210  contiguous with one another. The exit portion  210  of the recess  206  is formed with a machined conical or countersunk region  209  with an upwardly angled exit wall  211 . In a present recess  206 , the exit portion wall  211  is formed at an angle a of about  45  degrees to the surface of the plate  106 . The entrance portion  208  is formed as a machined or carved out section  213  with a straight entrance side wall  215 . The entrance portion  208  is machined out to a depth d 208  that is less than the depth d 209  of the countersunk region. 
         [0020]    In a present recess  206 , the countersunk exit region  209  is formed to a depth d 209  of about 0.093 inches and the entrance side straight side wall  215  is formed to a depth d 208  of about 0.065 inches, essentially creating a step  217  in the recess  206 . The finger  314  is configured so that it rides on the surface of the plate  106  and drops (by action of the spring  310 ) into the recess  206  at the entrance region. As the handle  102  is further rotated, the finger  314  moves up along the angled exit region wall  211  (see, e.g.,  FIGS. 3B and 3C ), and is urged back up into the handle  102  as the handle  102  moves beyond the recess  206 . However, rearward movement of the handle  102  is prevented by contact of the finger  314  with the straight side wail  215  of the entrance region  208 . In a preferred embodiment, the finger  314  projects into the recess  206 , but does not contact the bottom of the carved out region (the step  217 ), and most preferably, is a distance d 217  of about 0.06 inches from the step  217 . 
         [0021]    Returning to  FIG. 1 , the counter  100  includes a cover  402  that covers the lower portion of the counter  100 , and a cap  404 . The cover  402  includes a slot  406  that is sized to accommodate the indicator  118  on the central plate  116 . The counter  100  is held together by fasteners  412 , such as the illustrated shoulder bolts that extend through the locking plate  106  and into the cap  404 . The central plate  116  includes two notches  119  through which the bolts  412  pass as they extend from the locking plate  106  to the end cap  404 . 
         [0022]    As the handle  102  is rotated around the locking plate  106  in the forward direction, the finger  314  drops (by spring  310  force) into each recess  206 . In further urging the handle  102  in the forward direction, because the exit portion  210  has an upwardly sloping wall  211 , the finger  314  can move up and out of the recess  206  to advance to the next recess. However, because of the recess straight rear wall  215  (entrance portion  208 ), engagement of the finger  314  with the wall  215  prevents backward rotation of the handle  102 . 
         [0023]    When the counter  100  is assembled, the handle  102  is coupled to the locking plate  106  by the shaft  104 . The locking ring  120  holds the locking plate  106  against the spacing unit  114  and handle  102 . The locking ring  120  is configured to prevent the shaft  104  from separating from the locking plate  106  as the handle  102  is rotated. Because the shaft  104  is secured to the handle  102 , and the locking plate  106  is coupled to the handle  102 , the shaft  104  rotates around the central axis A 106  of the plate  106   
         [0024]    As the shaft  104  is rotated, the position indicator assembly  108  moves longitudinally along the length of the shaft  104 . The indicator  118  and notches  119  on the central plate  116  prevent the plate  116  from rotating with the shaft  104 . Accordingly, by rotating the handle  102 , the position indicator assembly  108  moves longitudinally along the shaft  104  toward the locking plate  106 . And, as set forth above, the handle  102  can only be rotated in one direction due to interference between the finger  314  and the recess entrance wall  215  when it is attempted to rotate the handle  102  in a backward or rearward direction. 
         [0025]    The recesses  206  are positioned along the surface of the locking plate  106  such that the movement from one recess  206  to an adjacent recess  206  results in the position indicator  108  moving a predetermined distance within the slot  406 . The angle Θ between adjacent recesses  206  (e.g., 360 degree rotation of the handle  102  divided by the number of recesses  206 ), in conjunction with the pitch of the threads on the shaft  104  (e.g., the number of threads per inch of the shaft  104 ) corresponds to a predetermined linear distance of movement along the shaft  104 . 
         [0026]    For example, if the shaft  104  has a thread pitch of 20 threads per inch, then rotation of the shaft 20 times will result in movement of the indicator  118  one inch along the length of the shaft  104 . With eight recesses in the plate  106 , one hundred sixty (160) discrete movements of the handle  102  will result in 1 inch of movement of the indicator  118 . Viewed another way if it is determined that the holder  600  has a useful life of 200 cycles, then movement of the indicator  118  (200/(8×20)) or 1.25 inches will indicate that the holder  600  has reached its useful life. Accordingly, a mark or indicator I (or some other indicia) can be provided on the cover  402 , adjacent to the slot  406  (as illustrated in  FIG. 1 ), to provide such indication of the number of uses or the percent of useful life remaining or used. 
         [0027]      FIG. 4  illustrates the counter  100  coupled to a sterilization challenge specimen holder  600 . The counter  100  is coupled to the holder  600  by fasteners, such as bolts  602  that pass through the openings  414  in the end cap  404 . After the counter  100  is installed, a user rotates the handle  102  clockwise before or after each use to increment the indicator  118 . When the maximum number of uses of has been reached, the holder  600  can be returned to be refurbished or disposed of as desired. 
         [0028]    All patents referred to herein, are hereby incorporated herein by reference, whether or not specifically done so within the text of this disclosure. 
         [0029]    In the present disclosure, the words “a” or “an” are to be taken to include both the singular and the plural. Conversely, any reference to plural items shall, where appropriate, include the singular. 
         [0030]    From the foregoing it will be observed that numerous modifications and variations can be effectuated without departing from the true spirit and scope of the novel concepts of the present disclosure. It is to be understood that no limitation with respect to the specific embodiments illustrated is intended or should be inferred. The disclosure is intended to cover by the appended claims all such modifications as fall within the scope of the claims.