Abstract:
Disclosed herein is a method that relates to resetting and firing a powder actuated setting tool. The method includes resetting the tool by torsionally urging a portion of a firing pin into axial alignment with a finger of a barrel of the tool and compressing the barrel of the tool toward a housing of the tool. The resetting further includes the finger urging the portion of the firing pin to a ready position in response to the compression of the barrel. The method further includes firing the tool by rotating a rotator and the firing pin to a position where the portion of the firing pin is unsupported by the finger.

Description:
BACKGROUND 
   In the construction and industrial industries, people are familiar with powder actuated setting tools. These are tools designed to forcefully expel a fastener into a workpiece by using an explosive powder charge to accelerate a piston which ultimately expels the fastener through physical contact therewith. In general, the tools resemble guns, having a barrel, housing, trigger, firing mechanism, charge and load (fastener). Such tools have been in existence for some time and are well disclosed in the patent literature. As powder actuated tools utilize a firing pin to ignite the powder charge, it is necessary to cycle the firing pin to a position where it is ready to fire. This has been done in the prior art by forcing a pin or a carrier for the pin into a ready to fire position against the action of a pair of coil springs. The linear compression force required to overcome the two coil springs, while certainly possible, and indeed operable, is relatively high. Such property causes the operator of the setting tool to need to bear down on the tool with considerably more force than might be desirable to place the setting tool in a position to dispense a fastener to the workpiece. 
   As will be appreciated by readers hereof, rapid completion of tasks is key in most endeavors whether they be private matters or commercial matters. High compression requirements as discussed above effectively slow the effort from both the time to compression standpoint and the operator fatigue standpoint. It is therefore understandable that high compression requirements to use a setting tool are not desirable as they negatively impact production. Since production must stay high, setting tools having lower compression requirements would be of benefit to the art. 
   SUMMARY 
   Disclosed herein is a powder actuated setting tool including a housing, a barrel in operable communication with the housing, a trigger mechanism at the housing and a rotary firing pin resetting mechanism in operable communication with the trigger mechanism. 
   Further disclosed herein is a method for resetting a firing pin in a powder actuated setting tool including imparting a torsional spring force to a firing pin resetting mechanism, extending a barrel of the setting tool to remove an impediment to rotational movement of the firing pin, and rotating the firing pin in response to the torsional spring force. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Referring now to the drawings wherein like elements are numbered alike in the several Figures: 
       FIG. 1  is an exploded view of a setting tool having a firing pin reset mechanism according to this disclosure; 
       FIG. 2  is an exploded view of components of the setting tool relevant to the firing pin reset mechanism; and 
       FIGS. 3   a – 3   d  are a series of views of the assembled firing pin reset mechanism illustrated in sequential positions. 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1 , a housing  10  is easily recognizable. Housing  10  contains when assembled, barrel guide  12 , firing mechanism  14 , trigger assembly  16  and a barrel  18 . Other components of the setting tool are not directly related to the object of this disclosure include, a barrel  18 , a piston  20 , a barrel set spring  22 , and a fastener magazine assembly  24 . Further illustrated is a firing mechanism reset finger  28  which causes movement of the firing mechanism when the barrel is cycled due to operator compression of the setting tool. 
   Referring to  FIG. 2 , an enlarged view of the components of the setting tool that are particularly relevant to this disclosure and together function as a firing pin resetting mechanism, among other functions is illustrated. From  FIG. 1 , the reader should recognize barrel guide  12  and barrel  18 . This provides an indication of where in the setting tool the particular components described hereunder reside. For clarity, it is noted that the right side of drawing  FIG. 2  will be oriented to the forward extent of the setting tool and the left side of the drawing toward the rearward extent of the setting tool. At a rearward end  30  of barrel guide  12  is a pin guide  32  to guide a firing pin  34  to a powder charge (not visible) in a combustion chamber (not visible) within the barrel  18 . Pin guide  32  includes a slot  33  for sliding passage of a portion of the firing pin  34  discussed hereunder. The firing pin itself includes an impact pin  36 , a stepped support  38  for impact pin  36 , a body  40  and a pin pullback arm  42  having thread  44 . Further, body  40  supports, protruding radially therefrom, a reset land  46 . Land  46  is about half as wide as slot  33  for operational reasons that will become clear hereinafter. The firing pin  34  is receivable not only within the inside dimension of pin guide  32  but within pin rotator  50 . Pin rotator  50  includes a substantially cylindrical body  52  having an opening  54  therein extending over at least a portion of the body  52 , and having a width similar to that of slot  33  to accommodate movement of reset land  46  and reset finger  28  during cycling of the firing mechanism. It should be noted that when assembled, guide  32 , firing pin  34  and rotator  50  are substantially circumferentially nested and coaxial. 
   Rotator  50  further includes a land receptor  56  sized to receive land  46  when the firing mechanism is in the ready to fire position. Receptor  56  is illustrated as one embodiment but it is important to note that the only surface of receptor  56  that is necessary to operation of the firing mechanism is surface  58  for it is surface  58  that causes the rotational movement of land  46  which allows the firing pin  34  to be accelerated toward a powder charge. Rotator  50  also includes a trigger lever recess  60 , making rotator  50  responsive to trigger  62  of the setting tool. The trigger lever  68  causes trigger action to interact with rotator  50  and thereby release firing pin  34  by pushing land  46  off of finger  28  pin  34  is propelled forwardly to strike the powder charge. 
   When assembled, guide  32  anchors one end  70  of a torsion spring  72  at anchor  74 . The other end  76  of torsion spring  72  is anchored at rotator  50  at anchor  78 . Torsion spring  72  acts to return rotator  50  and thus firing pin  34  to a “ready to set” position after firing of the setting tool by urging rotator  50  rotationally to a settable position. Torsion spring  72  is covered by disk  80  which also acts as a base for firing spring  90 . In one embodiment disk  80  includes shoulder  82  sized to receive spring  90  thereon. Pin pullback  42  extends slidably through disk  80  and a pullback spring  84  to engage a nut  86  on thread  44 . The pullback spring  84  operates to pullback the firing pin  34  slightly to remove contact between the impact pin  36  and a charge. 
   Finger  28  has been introduced above but not in context. Still referring to  FIG. 2 , finger  28  is connected to barrel  18 . In this embodiment finger  28  is inserted into a recess in barrel  18  (not in view) up to shoulder  92  and is secured there by reasonable means. Finger  28  is shaped to include a slide area  94  parallel to an axis of finger  28  which interacts with land  46 . 
   Operation of the firing mechanism is interrelated with compressive action on the tool causing barrel  18  to cycle into barrel guide  12 . As noted above, this occurs when the tool is in use by compressing the tool against a workpiece. Since finger  28  is fixedly connected to barrel  18 , finger  28  moves with barrel  18 . 
   With the information from the preceding paragraph, reference is made to  FIGS. 3   a – 3   d  wherein sequential views of the resetting mechanism are provided. In  FIG. 3   a  the tool is in the “just fired” position and the compressive force released with the firing pin forward (rightward in the drawing). Finger  28  is not visible in  FIG. 3   a  verifying that compressive force on the setting tool is not present and the land  46  is in position to be actuated by finger  28  upon compression of the setting tool. Components of the pin can be seen in the drawing to verify its location. These are land  46  and arm  42 . Spring  90  is shown in an uncompressed condition as it is extended to cause the firing pin to move forwardly into contact with the powder charge. 
   Moving to  FIG. 3   b , finger  28  has moved leftwardly in the figure to urge firing pin  34  rearwardly in the setting tool against the spring  90 . Land  46  is moved into receptor  56  by finger  28  which is itself moved due to compression of the setting tool and therefore barrel  18  movement. Spring  90  is compressed by the same movement. In the position illustrated in  FIG. 3   b , the tool is ready to fire. 
   Referring to  FIG. 3   c , the trigger lever  68  is actuated causing contact between lever  68  and recess  60 . This contact urges rotator  50  to rotate in the direction of the arrow in  FIG. 3   c  against the spring force of spring  72  (not visible in  FIG. 3   c ). Firing pin  34  is caused to rotate in the same direction as rotator  50  due to contact between land  46  and surface  58  of rotator  50 . As rotation of rotator  50  aligns surface  58  with surface  94  of finger  28 , land  46  is no longer supported in the “cocked” position and immediately moves forwardly (right in drawing) under the force of spring  90 . The firing pin  34  is illustrated, through the components thereof that are visible, in the fired position, already having been moved by spring  90 . 
   Rotator  50  remains in the position of  FIG. 3   c  until finger  28  is moved rightwardly (forwardly) due to uncompression of the setting tool, until land  46  is no longer prevented from rotating in the direction of the arrow in  FIG. 3   d  (illustration after removal of finger  28  and rotation of rotator  50  and land  46 ). At this point in the process, the setting tool is back in the uncompressed ready for compression (and “cocking”) position. 
   This arrangement as disclosed eliminates a coil spring that was required in the prior art and by doing so reduces overall compressive force needed to set the tool. 
   While one embodiment has been shown and described, modifications and substitutions may be made thereto without departing from the scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.