Patent Publication Number: US-8978517-B2

Title: Handheld electric capper and decapper

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the U.S. national phase application of PCT International Application No. PCT/US2009/050042, filed Jul. 9, 2009, which claims priority to U.S. Provisional Patent Application No. 61/079,207, filed Jul. 9, 2008, the contents of such applications being incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a powered hand tool used to secure or remove a cap on a bottle or vial. The hand tool has a housing portion which the user holds and includes switches for the user to control the capping/decapping action. The capping action results from a motor causing a plunger to move downward, thereby actuating a plurality of jaws to secure the cap on the bottle or vial. 
     2. Description of the Prior Art 
     Some bottles or vials to contain liquid samples or other laboratory materials have an opening thereinto which includes a lip onto which a cap is crimped to seal the bottle or vial. In general, for example, the crimp cap can be aluminum or steel, with sample diameters of from about 8 mm to about 22 mm, or greater. Typically the crimp cap has a cylindrical portion which fits over the bottle lip and is then crimped thereunder; the crimp cap has a top with a circular opening therein; the inside of the crimp cap contains a rubber circular portion next to the crimp cap and an elastomeric circular portion next to the bottle, although many variations are known. In use, a sample is placed into the bottle or vial and a crimp cap is placed thereon. A crimping tool is then employed to crimp the crimp cap onto the bottle. When a portion of the sample is to be removed, a syringe is inserted through the rubber and elastomeric circular portions and the desired amount of the sample is removed. 
     Alternatively, there are a number of bottle capping machines currently used to apply screw caps onto bottles. In general such machines employ a reciprocating mechanism to reciprocate a screw cap applying spindle assembly through a capping cycle. A screw cap chuck, typically constructed of a tool grade steel, is attached to the spindle. These machines operate at a predetermined downward stroke while applying a pre-determined torque to the screw cap. An example of such an apparatus is shown in U.S. Pat. No. 3,031,822, which is incorporated herein by reference. 
     SUMMARY OF THE INVENTION 
     The present invention provides in at least one embodiment a hand tool for capping or removing a cap from a container. The tool comprises a housing and a gearbox assembly positioned within the housing. The gearbox assembly includes a motor, a lead screw rotated by the motor and a screw pusher engaged by the lead screw and moved axially based on rotation of the lead screw. The gearbox assembly is adapted to engage a jaw set assembly with the screw pusher operatively engaging a jaw set of the jaw set assembly. 
     In at least one embodiment, the housing has a central axis and a hand grip area is defined about the central axis of the housing. Furthermore, the gearbox assembly has a drive axis that extends substantially coaxial with the central axis. 
     In at least one embodiment, the gearbox assembly is adapted to engage jaw set assemblies having different configurations and the hand tool further comprises a sensor assembly configured to sense the configuration of an engaged jaw set assembly and control the motor and a stroke of the lead screw based thereon. 
     In at least one embodiment, the hand tool further comprises a sensor configured to determine if a jaw set assembly is engaged with the gearbox assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a right elevation view of an electric hand tool in accordance with an embodiment of the present invention. 
         FIG. 2  is a left elevation view of the electric hand tool of  FIG. 1 . 
         FIG. 3  is a front elevation view of the electric hand tool of  FIG. 1 . 
         FIG. 4  is a rear elevation view of the electric hand tool of  FIG. 1 . 
         FIG. 5  is an isometric view of the electric hand tool of  FIG. 1 . 
         FIG. 6  is a top plan view of the electric hand tool of  FIG. 1 . 
         FIG. 7  is an isometric view of the housing assembly of the electric hand tool of  FIG. 1 . 
         FIG. 8  is a partial exploded view of the housing assembly of  FIG. 7 . 
         FIG. 9  is an isometric view of the gearbox assembly of the electric hand tool of  FIG. 1 . 
         FIG. 10  is a partial exploded view of the gearbox assembly of  FIG. 9 . 
         FIG. 11  is an isometric view of the lower frame assembly of the electric hand tool of  FIG. 1 . 
         FIG. 12  is a cross-sectional view of the lower frame with the screw pusher assembled therein. 
         FIG. 13  is a partial exploded view of the lower frame assembly of  FIG. 11 . 
         FIG. 14  is an exploded view of the sensor carrier assembly of the electric hand tool of  FIG. 1 . 
         FIG. 15  is an isometric view the sensor carrier assembly of  FIG. 14 . 
         FIG. 16  is an exploded isometric view of an exemplary crimping jaw set assembly. 
         FIG. 17  is a top plan view of the crimping jaw set assembly of  FIG. 16 . 
         FIG. 18  is a cross-sectional view along the line  18 - 18  in  FIG. 17 . 
         FIG. 19  is an exploded isometric view of an exemplary decapping jaw set assembly. 
         FIG. 20  is a top plan view of the decapping jaw set assembly of  FIG. 19 . 
         FIG. 21  is a cross-sectional view along the line  21 - 21  in  FIG. 20 . 
         FIG. 22  is a front isometric view of the jaw sensor assembly of the electric hand tool of  FIG. 1 . 
         FIG. 23  is a rear isometric view of the jaw sensor assembly of  FIG. 22 . 
         FIG. 24  is an exploded view of the jaw sensor assembly of  FIG. 22 . 
         FIG. 25  is an expanded isometric view of a portion of the gearbox assembly of  FIG. 9 . 
         FIG. 26  is an isometric view of the activation button assembly of the electric hand tool of  FIG. 1 . 
         FIG. 27  is a cross-sectional view of the activation button assembly of  FIG. 26 . 
         FIG. 28  is an exploded view of the activation button assembly of  FIG. 26 . 
         FIG. 29  is a top isometric view of the top cap assembly of the electric hand tool of  FIG. 1 . 
         FIG. 30  is a bottom isometric view of the top cap assembly of  FIG. 29 . 
         FIG. 31  is an exploded view of the top cap assembly of  FIG. 29 . 
         FIG. 32  is an isometric view of an exemplary tool holder for use with the electric hand tool of the current invention. 
         FIG. 33  is a partial isometric view of the tool holder of  FIG. 32  with a tool supported thereby. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An electric hand tool  10  in accordance with a first embodiment of the present invention will be described with reference to  FIGS. 1-31 . Referring to  FIGS. 1-8 , the electric hand tool  10  generally comprises a housing assembly  20  to which are connected interchangeable jaw set assemblies  200 . Each jaw set assembly  200  includes a jaw set housing  202  configured for connection to a pusher end  22  of the housing assembly  20 . As illustrated in  FIGS. 1-5 , a plurality of jaw members  210  extend from the jaw set housing  202 . The jaw members  210  are pivotally supported within the jaw set housing  202  in a known manner such that they may pivoted between open and closed positions in response to engagement by a pusher screw in a known manner. The jaw members  210  may be configured for use in crimping a crimp cap (not shown) upon a vial or bottle (not shown) or may be configured for decapping of a vial or bottle. Alternatively, the jaw set assembly  200  may be configured as a screw cap chuck such that the jaw members  210  grip the cap while a capping or decapping torque is applied thereto. Various configurations of jaw members  210  are known and may be utilized with the present invention. It is desirable that a plurality of differently configured jaw set assemblies  200  are interchangeably connectable to the housing assembly  20 . For example, jaw set assemblies  200  for capping and decapping bottles of various sizes may be provided. 
     In the present embodiment, the housing assembly  20  is defined by opposed housing shell components  21  and  23  (see  FIG. 8 ). The housing shell components  21  and  23  may be connected by screws  24  or any other suitable means. As shown in  FIG. 8 , a lower frame  62  is secured between the housing shell members  21  and  23  and defines the pusher end  22  of the housing assembly  20 . At the opposite end, a top cap  30  is positioned about and connected to the opposed housing shell members  21  and  23 , thereby closing the end of the housing assembly  20 . While the housing assembly  20  described herein has a clamshell configuration, other configurations may also be utilized. 
     As illustrated in  FIG. 1 , the hand tool  10  generally extends along a central axis CA. In the present embodiment, the housing assembly  20  defines a handle area  26  proximate to the top cap  30  end of the housing assembly  20  and extending about the central axis CA. The handle area  26  in the present embodiment has a reduced circumference. The activation button  80  for activating the motor as described hereinafter is positioned within or adjacent to the handle area  26 . In this manner, a user may hold the hand tool  10  about the central axis CA, providing an ergonomic, balanced configuration for operation of the tool. While the handle area  26  extends about the central axis CA, the utility of the invention is not limited to the specific configuration of the housing assembly  20  illustrated herein and may be achieved using other configurations having a different ornamental appearance. 
     Referring to  FIGS. 8-10 , a gearbox assembly  40  is secured within the housing assembly  10  and has a drive axis DA which preferably is substantially coaxial with the central axis CA. The gearbox assembly  40  generally includes a motor  42  supported relative to the lower frame assembly  60  with a series of gears therebetween. As shown in  FIG. 10 , an output gear  41  is provided on the output shaft of the motor  42 . In the present embodiment, the output gear  41  engages a first series of planet gears  43  supported on a first carrier assembly  44 . The first carrier assembly  44  in turn has an output planet carrier gear  45 . The number and arrangement of the planet gears  43  and the output planet carrier gear  45  are configured to provide a desired gear ratio. The first carrier assembly  44  is positioned in a first frame member  47  which is configured to connect to a motor frame member  46  about the motor output gear  41 . 
     The output planet carrier gear  45  engages the planet gears  53  of a second, optical sensor carrier assembly  50 . With reference to  FIGS. 14 and 15 , the optical sensor carrier assembly  50  is similar to the first carrier assembly  44 , but further includes an encoder ring  54 . As illustrated therein, a plurality of planet gears  53  are supported by planet gear pins  51  extending from the planet carrier  52 . The opposite face of the planet carrier  52  has an output planet carrier gear  55  attached thereto. The number and arrangement of the planet gears  53  and the output planet carrier gear  55  are configured to provide a desired gear ratio. The encoder ring  54  is positioned about the output planet carrier gear  55  and includes a plurality of spaced apart radially extending teeth  56 . Crimp tabs  57  extend between some of the teeth  56  and are configured to be crimped onto notches  59  in the planet carrier  52 , as shown in  FIG. 15 , to retain the encoder ring  54  attached to the planet carrier  52 . A sensor  124 , as described hereinafter, is configured to monitor passage of the individual teeth  56 , thereby facilitating monitoring the speed, direction, and position of rotation of the optical sensor carrier assembly  50 . The optical sensor carrier assembly  50  is positioned in a second frame member  48  which is configured to connect to the first frame member  47 . An opening  125  is provided through frame member  48  to facilitate passage of the sensor  124 . 
     The output planet carrier gear  55  is configured to engage the input planet gears  73  of the lead screw  70  which is part of the gearbox assembly  60 . Referring to  FIGS. 11-13 , the gearbox assembly  60  includes the lower frame  62  which provides a generally hollow frame structure. The lower frame  62  includes upper portion  68  defining a first open end  61  and a lower portion  64  defining a second open end  63 . Side rails  66  extend between the upper portion  68  and the lower portion  64 . A shoulder  65  is defined about the lower portion  64  spaced from the open end  63 . A lock rod opening  69  extends through the shoulder  65  with a sensor rod opening  67  on each side thereof. The lower portion  64  defines the pusher end  22  of the assembled housing assembly  20 . The upper portion  68  is configured for attachment with a third frame member  49  that extends about the input planet gears  73 . Referring to  FIGS. 9 and 10 , screws  39  or the like extend through the motor frame member  46 , the frame members  47 ,  48  and  49 , and engage the upper portion  68  of the lower frame  60 , thereby interconnecting the gear box assembly  40 . 
     Referring again to  FIGS. 11-13 , the lead screw  70  includes a planet head  72  with a shank  71  extending therefrom. In the present embodiment, a portion  74  of the shank  71  is non-threaded and a portion  76  of the shank  71  is threaded. The input planet gears  73  are rotatably supported on the planet head  72  and rotation of the input planet gears  73  causes the shank  71  to rotate based on the gear ratio therebetween. Accordingly, rotation of the motor  42  causes rotation of the lead screw shank  71  at a speed and direction based on the gear ratios of the first carrier assembly  44 , the optical sensor carrier assembly  50  and the input planet gears  73 . Rotation of the shank  71  can thereby be controlled by controlling the rotational output of the motor  42 . 
     The lead screw shank  71  is positioned through the open end  61  of the lower frame  60  and the threaded portion  76  threadably engages the screw pusher  90  positioned within the lower frame  60 . A series of washer and bearing members  77 ,  78  or the like may be provided between the lead screw  70  and the lower frame upper portion  68 . Referring to  FIGS. 12 and 13 , the screw pusher  90  has an open end  91  leading to an internally threaded portion  93 . The threaded portion  76  of the lead screw  70  threadably engages the internally threaded portion  93 . A guide groove  94  extends from one or both sides of the screw pusher  90  and is configured to move along rail  96  to guide axial movement of the screw pusher  90 . As illustrated in  FIG. 12 , the rail  96  may be secured to one of the side rails  66  via pins  97  and a screw  98 , but may otherwise be connected or, alternatively, be formed integrally with the side rail  66 . Engagement of the guide groove  94  with the rail  96  also prevents rotation of the screw pusher  90 . As such, rotation of the lead screw  70  causes the screw pusher  90  to move axially upward or downward such that the screw pusher  90  engages the jaw set assembly  200  as desired to move the jaw members  210 . A pusher tip  95  may be provided on the forward end of the screw pusher  90 . 
     Referring to  FIGS. 16-18 , a jaw set assembly  200 ′ that is an exemplary crimping jaw set assembly will be described. The illustrated jaw set assembly  200 ′ is configured to crimp a cap (not shown) on a bottle or vial, but can be alternatively be configured as a screw cap chuck for applying or removing a screw cap. Furthermore, while a specific jaw configuration is described herein, the invention is not limited to such and may utilize other configurations. The exemplary jaw set assembly  200 ′ includes a housing  202 ′ having a jaw opening  201  at one end and a connection opening  230  at the other end. As shown in  FIG. 16 , the external surface of the housing  202 ′ desirably, but not necessarily, is provided with a visual indicia  232 ′ of the configuration of the jaw set assembly  200 ′. For example, the indicia  232 ′ shows “20 mm ↓” which would indicate that the current jaw set assembly  200 ′ is a crimper (indicated by the arrow down) for a 20 mm vial. The specific configuration and location of the indicia  232 ′ may be varied. 
     The connection opening  230  is configured for attachment to the lower frame  62 . A rim  204  is defined about the connection opening  230  and is configured to abut against the shoulder  65  of the lower frame  62  upon connection of the jaw set assembly  200 ′. In the illustrated embodiment, the connection opening  230  has internal threads for a threaded connection to the lower frame, but other connection means may be utilized. The rim  204  includes at least one recess  205 , four in the illustrated embodiment, configured to receive a portion of a lock rod  116  which helps to prevent inadvertent unscrewing of the jaw set assembly  200 ′ as will be described hereinafter. 
     A portion of each jaw  210  extends through the jaw opening  201  with a jaw shoulder  211  abutting a jaw ring  206  to retain the jaws  210  in the housing  202 ′. The opposite ends of the jaws  210  are engaged by a biasing member  212  such that the jaws  210  are biased to the open position shown in  FIG. 18 . A cam member  208  is positioned within the jaws  210  and includes a tapered portion  207  and a contact portion  209 . In the open position, the rear ends of the jaws  210  are axially aligned with the tapered portion  207  such that the rear ends are biased radially inward and the jaws  210  remain in the open position. Axial movement of the cam member  208  toward the jaw opening end of the housing  202 ′ causes the contact portion  209  to contact the rear ends of the jaws  210  which causes the jaws  210  to pivot and bring the forward ends of the jaws  210  radially inward. 
     Axial movement of the cam member  208  is controlled by a plunger rod  220  having a forward end  221  connected to the cam member  208 . In the illustrated embodiment, the forward end  221  is press fit into connection with the cam member  208 , but other connection methods, for example, a threaded connection, may alternatively be utilized. A barrel  214  is positioned in the housing  202 ′ and defines a stepped through bore  215  through which the plunger rod  220  extends. A spring  218  is positioned in the stepped through bore  215  between a forward shoulder  217  defined by the barrel  214  and a shoulder  223  defined by the plunger rod  220  such that the plunger rod  220 , and thereby the cam member  208 , are biased rearward. The barrel  214  is secured in the housing  202 ′ via a retaining ring  216  or the like. The barrel  214  desirably closes the connection opening  230  except for the through bore  215  from which the plunger rod  220  extends. In this way, the jaw set assembly  200 ′ provides a self-contained, interchangeable assembly with the actuating member, i.e. the plunger rod  220 , easily accessible at the connection opening  230 . 
     Referring to  FIGS. 19-21 , a jaw set assembly  200 ″ that is an exemplary decapping jaw set assembly will be described. While a specific jaw configuration is described herein, the invention is not limited to such and may utilize other configurations. The exemplary jaw set assembly  200 ″ includes a housing  202 ″ having a jaw opening  201  at one end and a connection opening  230  at the other end. As shown in  FIG. 19 , the external surface of the housing  202 ″ desirably, but not necessarily, is provided with a visual indicia  232 ″ of the configuration of the jaw set assembly  200 ″. For example, the indicia  232 ″ shows “20 mm  ” which would indicate that the current jaw set assembly  200 ′ is a decapper (indicated by the arrow up) for a 20 mm vial. The specific configuration and location of the indicia  232 ″ may be varied. 
     The connection opening  230  is configured for attachment to the lower frame  62 . A rim  204 ″ is defined about the connection opening  230  and is configured to abut against the shoulder  65  of the lower frame  62  upon connection of the jaw set assembly  200 ″. In the illustrated embodiment, the connection opening  230  has internal threads for a threaded connection to the lower frame, but other connection means may be utilized. The rim  204  includes at least one recess  205 , four in the illustrated embodiment, configured to receive a portion of a lock rod  116  which helps to prevent inadvertent unscrewing of the jaw set assembly  200 ′ as will be described hereinafter. The rim  204 ″ also includes at least one notch  203 , in the illustrated embodiment, a notch  203  adjacent to each recess  205 , which is configured to receive a portion of a sensor rod  110  as described hereinafter. 
     A portion of each jaw  210 ″ extends through the jaw opening  201 . In the present jaw set assembly  200 ″, the jaw shoulder  211 ″ is narrower and is spaced from the jaw ring  206  with a spiral spring  224  or the like positioned between the shoulder  211 ″ and the jaw ring  206 . The jaw ring  206  retains the jaws  210 ″ in the housing  202 ″ but allows slight axial movement of the jaws  210 ″ as described hereinafter. The opposite ends of the jaws  210 ″ are engaged by a pair of biasing members  222  such that the jaws  210 ″ are biased to the open position shown in  FIG. 21 . A cam member  208 ″ is positioned within the jaws  210 ″ and includes a tapered portion  207 , a contact portion  209  and a forward extending portion  213 . In the open position, the rear ends of the jaws  210 ″ are axially aligned with the tapered portion  207  such that the rear ends are biased radially inward and the jaws  210 ″ remain in the open position. Forward axial movement of the cam member  208 ″ relative to the jaws  210 ″ causes the contact portion  209  to contact the rear ends of the jaws  210 ″ which causes the jaws  210 ″ to pivot and bring the forward ends of the jaws  210 ″ radially inward. 
     In this exemplary jaw set assembly  200 ″ which is configured for decapping, the cam member  208 ″ and the jaws  210 ″ are configured to initially move axially forward together such that the forward extending portion  213  can contact the cap (not shown) prior to pivoting of the jaws  210 ″. Wave spring  228  extends between the barrel  214  and a wave spring collar  226  in contact with the rear ends of the jaws  210 ″ such that the jaws  210 ″ are urged forward. The jaws  210 ″ do not move forward until movement of the cam member  208 ″ based on the contact of the jaws  210 ″ against the cam member  208 ″ and the rearward force on the cam member  208 ″. As such, the jaws  210 ″ remain a given distance from the spiral spring  224 . This will be the distance the cam member  208 ″ and jaws  210 ″ can move axially together before the jaws  210 ″ begin to pivot, as explained below. 
     Axial movement of the cam member  208 ″, with the jaws  210 ″ and relative to the jaws  210 ″, is controlled by a plunger rod  220  having a forward end  221  connected to the cam member  208 ″. In the illustrated embodiment, the forward end  221  is press fit into connection with the cam member  208 ″, but other connection methods, for example, a threaded connection, may alternatively be utilized. The barrel  214  is positioned in the housing  202 ′ and defines a stepped through bore  215  through which the plunger rod  220  extends. A spring  218  is positioned in the stepped through bore  215  between a forward shoulder  217  defined by the barrel  214  and a shoulder  223  defined by the plunger rod  220  such that the plunger rod  220 , and thereby the cam member  208 ″, are biased rearward. The barrel  214  is secured in the housing  202 ″ via a retaining ring  216  or the like. 
     Upon initial forward movement of the plunger rod  220 , the cam member  208 ″ will move forward. The jaws  210 ″ will also move forward based on the bias of the wave spring  228  between the fixed barrel  214  and the moveable wave spring collar  226 . The cam member  208 ″ and jaws  210 ″ will move together until the shoulder  211 ″ contacts the spiral spring  224 /retaining ring  206  at which point the jaws  210 ″ will no longer be able to move forward and the cam member  208 ″ will move forward relative to the jaws  210 ″ such that the contact portion  209  contacts the rear ends of the jaws  210 ″ and causes the forward ends of the jaws  210 ″ to pivot radially inward. 
     The barrel  214  desirably closes the connection opening  230  except for the through bore  215  from which the plunger rod  220  extends. In this way, the jaw set assembly  200 ″ provides a self-contained, interchangeable assembly with the actuating member, i.e. the plunger rod  220 , easily accessible at the connection opening  230 . 
     In each of the jaw set assemblies  200 ′,  200 ″, axial movement of the plunger rod  220  is effected by axial movement of the screw pusher  90 . Forward movement of the screw pusher  90  will contact the plunger rod  220  and drive the plunger rod  220  forward against the bias of the spring  218 . Upon retraction of the screw pusher  90 , the spring  218  biases the plunger rod  220  rearward to the open positions illustrated in  FIGS. 18 and 21 . 
     A sensor assembly  120  is provided to control the length of the stroke of the screw pusher  90  and thereby the plunger rod  220 . Referring to  FIGS. 8-10 , the sensor assembly  120  includes a plate  121  which is attached to frame members  47 ,  49  of the lower frame assembly  60 . An optical rotational sensor  124  is secured on the plate  121  and is positioned to extend through the opening  125  such that it is aligned with the encoder ring  54 . The optical rotational sensor  124  is configured to monitor the passage of the distinct teeth  56 . Based on the passage of teeth  56 , the sensor  124  itself, or a motor control board  130 , may determine the speed, direction and angle of rotation. Based on this information, the length of the stroke generated by the lead screw  70  may also be determined. 
     As indicated above, the present hand tool  10  preferably is useable with interchangeable jaw set assemblies  200 ,  200 ′,  200 ″ having different configurations. As such, the stroke required for one jaw set assembly  200  may be different than for another jaw set assembly  200 . To ensure a proper stroke, the present embodiment of the invention includes a jaw sensor assembly  100 . 
     Referring to  FIGS. 22-25 , the jaw sensor assembly  100  of the present embodiment includes a body  102  including upper and lower shelves  101  and  111 . The upper shelf  101  includes a pair of upper sensor rod slots  103  and the lower shelf  111  includes a pair of lower sensor rod slots  105  aligned with the upper slots  103 . Each slot pair  103 ,  105  is configured to receive a respective sensor rod  110   a,b . Each sensor rod  110   a,b  has a shaft  112  which terminates in a sensor contact pad  114  at one end and has a snap fit member  113  positioned adjacent thereto. The shafts  112  extend through the slots  103  and  105  with a spring  115  thereabout and extending between the shelves  101  and  111 . The snap fit member  113  passes through the lower slot  105  and then snap fits relative to the lower shelf  111 , thereby preventing downward movement of the sensor rod  110   a,b.    
     A lock rod  116  extends along the rear of the body  102  parallel to the sensor rods  110   a,b . The lock rod  116  has a notched end  118  and a contact end  119  with a groove  117  defined therebetween. An aperture  106  extends through the body  102  such that the lock rod groove  117  is aligned therewith. A lock button  107  is positioned along the front of the body  102  and includes a connector  108  that extends through the aperture  106  and connects to the lock rod  116  in the groove  117 . A spring  109  extends between the upper shelf  101  and a shoulder about the groove  117  such that the lock rod  116  is biased forward. 
     Referring to  FIGS. 9 ,  10  and  25 , the jaw sensor assembly  100  is attached to the lower frame assembly  60  such that the notched end  118  of the lock rod  116  extends behind the sensor plate  121  and engages an unlock member  126  which prevents movement of the lock rod  116  during an operation of the device. The shafts  112  of the sensor rods  110  extend adjacent to each side of the sensor plate  121  with each shaft  112  aligned with a corresponding axial movement sensor  127 . Each axial movement sensor  127  is configured to sense the axial position of a respective sensor rod  110 . At the opposite end, the contact end  119  of the lock rod  116  extends through the lock rod opening  69  such that the lock rod contact end  119  is beyond the shoulder  65 . Similarly, each sensor contact pad  114  extends into a respective sensor rod opening  67  in the shoulder  65  and extends beyond the shoulder  65 . 
     Referring to  FIGS. 16 ,  19  and  25 , operation of the jaw sensor assembly  100  will be described. As explained above, either of the housings  202 ′,  202 ″ may be attached to the lower portion  64  of the frame  62  until the rim  204  abuts the shoulder  65 . As the jaw set housing  202 ′,  202 ″ is fully positioned about the lower portion  64  of lower frame  62 , the lock rod contact end  119  is received within one of the recesses  205 , thereby preventing inadvertent rotation of the housing  202 ′,  202 ″ in a reverse, removing direction. To remove the jaw set assembly  200 , the lock rod  116  is retracted against the force of the spring  109  until the contact end  119  disengages from the recess. As explained above, if the device is in operation, engagement of the unlock member  126  with the notch  118  will prevent retraction of the lock rod  116 . 
     The sensor rods  110   a  and  110   b  are configured to provide one or more sensing functions. In the present embodiment, one of the sensor rods  110   a  is configured to determine if a jaw set assembly  200  has been positioned on the housing  20 . The other sensor rod  110   b  is configured to determine if the jaw set assembly is a crimping jaw set assembly  200 ′ or a decapping jaw set assembly  200 ″. 
     The contact pad  114  of sensor rod  110   a  is positioned next to the lock rod  116  such that it will not be aligned with a recess  205  or a notch  203  when the assembly  200 ′ or assembly  200 ″ is connected and the lock rod  116  is received in the recess  203 . As such, the contact pad  114  will contact a portion of the rim  204 , and will thereby be moved axially when either jaw set assembly  200 ′,  200 ″ is attached. The axial movement of the sensor rod  110   a  is detected by the respective axial movement sensor  127  and signals to the motor control board that a jaw set assembly  200 ′ or  200 ″ is attached. 
     The contact pad  114  of sensor rod  110   b  is positioned on the opposite side the lock rod  116  such that it will align with one of the notches  203  when the jaw set assembly  200 ″ is connected and the lock rod  116  is received in the recess  203 . As such, when a decapping jaw set assembly  200 ″ is connected, the contact pad  114  will be received in the notch  203  and will not cause the sensor rod  110   b  to move axially, but instead it will remain in its default position. Since the rim  204  of the crimping jaw set assembly  200 ′ does not include any notches, the contact pad  114  will contact the rim  204  and the sensor rod  110   b  will move axially. The axial movement of the sensor rod  110   b  is detected by the respective axial movement sensor  127  and signals to the motor control board that a crimping jaw set assembly  200 ′ is attached. With no axial movement of sensor rod  110   b , the motor control board determines that a decapping jaw set assembly  200 ″ is attached. Other configurations may be utilized, for example, different depth notches, to further identify the jaw set assembly  200 , for example, the size of the jaw set. 
     Knowing the configuration of the jaw set assembly  200 , the appropriate stroke may be utilized. As explained above, in the illustrated embodiment, movement of the stroke of the screw pusher  90  forward or rearward is effected by the motor  42 . Referring to  FIG. 8 , a motor control circuit board  130  is positioned within the housing assembly  20  and is in electrical communication between the motor  42 , the activation button  80 , a power control board  140 , sensors  124  and  127  and unlock member  126 . The power control board  140  has an electrical input  142 . In the present embodiment, the electrical input  142  is configured for connection to an electrical cord  144  (see  FIGS. 1-6 ), however, other power sources, for example, batteries, may be utilized. The power control board  142  is configured to determine when the hand tool  10  has been powered up, e.g. plugged in or turned on if an on/off switch is provided. Other functions of the power control board  142  will be described hereinafter. 
     Referring to  FIGS. 26-28 , the activation button  80  includes a button member  82  with a contact member  84  extending therefrom. In the present embodiment, overmold assembly  88  is provided about the button member  82 , but other configurations may be utilized. Referring again to  FIG. 8 , the activation button  80  is positioned in the housing assembly  20  such that the contact member  84  is aligned with a activation switch  132  on the motor control circuit board  130 . A spring  86  extends from the button member  82  and is configured to be secured within the housing assembly  20  and urge the button member  82  to a non-contact position. 
     In general terms, upon power up of the hand tool  10 , as detected by the power control board  142 , the motor control circuit board  130  is configured to determine through sensors  127  if a jaw set assembly  200  is attached and if so, whether it is a crimping jaw set assembly  200 ′ or a decapping jaw set assembly  200 ″. If a jaw set assembly  200  is attached, the motor control circuit board  130  is configured to run the motor  42  in reverse during a ‘homing’ cycle, where the screw pusher  90  is drawn up into the unit until it reaches a home position. The home position may be identified by a limit switch (not shown) or by other means. When the activation button  80  is pressed, the motor control board  130  controls the motor  42  to drive the lead screw  70 , thereby causing the screw pusher  90  to move forward which presses against the plunger rod  220  of the attached jaw set assembly  200 ,  200 ′,  200 ″ and causes the jaws  210  to close. As described above, the encoder ring  54  in the gearbox assembly  40  is used to monitor the length of the lead screw  70  stroke. Once the stroke is complete, the motor  42  is reversed and the screw pusher  90  is moved back to the home position by the lead screw  70 , opening the jaw set. 
     The control board  130  preferably has predefined actuation depending on the type of jaw set assembly  200 ′,  200 ″ that is attached. For example, when a decapping jaw set assembly  200 ″ is detected on the unit, the control board  130  may be configured to operate the motor for a maximum stroke length as precision is not required. Furthermore, the unit may give an indication of a decapping operation, for example, by lighting all of the indicator lights of the light indicator  35  described hereinafter. 
     When a crimping jaw set assembly  200 ′ is detected, the control board  130  is preferably configured to operate the motor  42  to achieve a predetermined stroke that is less than the maximum stroke length. In some instances, a predetermined stroke may be too long or too short. As such, the top cap  30  of the present embodiment of the invention is provided with a user stroke control input  32  as shown in  FIGS. 29-31 . The stroke control input  32  includes a pair of input buttons  31  and  33  which engage a stroke control board  150  which in turn is in communication with the motor control board  130 . One of the input buttons  31  is configured to send a signal to the motor control board  130  to decrease the stroke while the other input button  33  is configured to send a signal to the motor control board  130  to increase the stroke. A light indicator  35  or the like may be provided in the top cap  30  and associated with the stroke control board  150  to provide a visual indication of the current length of the stroke, as adjusted. In an exemplary embodiment, the lights of the light indicator  35  will have different colors which indicate different stroke lengths. For example, a green light will indicate a shorter stroke length, a yellow light will indicate an average stroke length and a red light will indicate a longer stroke length. Other configurations of the lights may also be utilized. The stroke control board  150  may include a non-volatile ram configured to remember an increase or decrease in stroke for a given application such that the same stroke can be provided again. 
     Referring to  FIGS. 32 and 33 , an exemplary tool holder  250  for use with the electric hand tool  10  will be described. The tool holder  250  includes a base  252  with an arm  254  extending therefrom. The arm  254  defines an upper holder  256  and a lower holder  260 . The lower holder  260  includes a semi-circular, flexible grip  262  configured to receive and grasp the jaw set housing  202  as shown in  FIG. 33 . The upper holder  256  includes a forked grip  258  with a pair of tines that extend on the sides of the handle area  26  of the tool  10  as shown in  FIG. 33 . The end of each tine has a knob portion  259  such that the handle area  26  is releasably held in the forked grip  258 . The hand tool  10  can be releasably stored in the tool holder  250 , or may be maintained and used while in the tool holder  250 . When stored in the tool holder  250 , the hand tool  10  is in a proper orientation with the activation button  80  easily accessible. The hand tool  10  may additionally or alternatively be operated by a foot pedal (not shown) or the like connected to the hand tool  10 . 
     While preferred embodiments of the invention have been shown and described herein, it will be understood that such embodiments are provided by way of to example only. Numerous variations, changes and substitutions will occur to those skilled in the art without departing from the spirit of the invention. Accordingly, it is intended that the appended claims cover all such variations as fall within the spirit and scope of the invention.