Patent Publication Number: US-2023145061-A1

Title: Tool with charge advance mechanism

Description:
PRIORITY 
     This application is a continuation of and claims priority to and the benefit of U.S. patent application Ser. No. 17/409,959, filed on Aug. 24, 2021, which is a continuation of, and claims priority to and the benefit of U.S. patent application Ser. No. 16/168,320, filed on Oct. 23, 2018, now issued as U.S. Pat. No. 11,123,851, on Sep. 21, 2021, which claims priority to and the benefit of Australian Patent Application No. 2018250391, which was filed on Oct. 16, 2018, and claims priority to and the benefit of Australian Patent Application No. 2017904368, which was filed on Oct. 27, 2017, the entire contents of each of which are incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates generally to a tool with a charge advance mechanism and, more specifically but not exclusively, to a powder actuated fastening tool having a charge advance mechanism for advancing a strip of powder charges relative to the tool. 
     BACKGROUND 
     It is has been previously proposed to provide a powder actuated fastening tool which operates on a strip of explosive powder charges to drive fasteners into a workpiece. It is necessary for the powder charge strip to be driven progressively through the tool such that the strip is moved through the tool so that successive charges are used for firing successive fasteners through a barrel of the tool. In this way, it is desirable that each of the powder charges in the strip is progressively depleted to drive the fasteners from the fastening tool. 
     However, the applicant has identified that there is a problem with existing powder actuated fastening tools in that the powder charge strip may not be accurately or adequately moved through the tool such that a charge may be out of alignment with the barrel, raising the problem of potentially having charges damaged by the tool or even activated outside of the barrel of the tool, which may be potentially dangerous or at least destructive to the tool. 
     Examples of the present disclosure seek to provide an improved tool with charge advance mechanism which may avoid or at least ameliorate disadvantages of existing powder actuated tools. 
     SUMMARY 
     In accordance with one aspect of the present disclosure, there is provided a powder actuated fastening tool including a charge advance apparatus for advancing a powder charge strip relative to a barrel of the tool, wherein the charge advance apparatus includes a rotatable ratchet having teeth for engaging receptacles formed in the powder charge strip, and a charge advance member coupled to a trigger of the tool, wherein the charge advance member acts on the rotatable ratchet to rotate the ratchet in response to actuation and/or release of the trigger, such that the rotation of the ratchet causes advance of the powder charge strip relative to the barrel. 
     Preferably, the barrel has mounted thereon an alignment member which moves relative to the ratchet when the barrel is brought from the open position to the closed position to ensure a charge of the powder charge strip is in alignment with the barrel. 
     More preferably, when the barrel is brought from the open position to the closed position, the alignment member is moved into abutment with the ratchet to prevent the ratchet from rotating, thereby preventing the charge from moving out of alignment with the barrel. 
     Even more preferably, the rotatable ratchet has a plurality of straight sides, such that when the barrel is brought from the open position to the closed position, the alignment member is moved into abutment with one of the straight sides to prevent rotation of the ratchet. 
     Even more preferably, the alignment member is moved into abutment with said straight side in a direction parallel to the straight side. In one form, the alignment member is in the form of an elongated rod. 
     Preferably, the rotatable ratchet is hexagonal. 
     Preferably, the rotatable ratchet is arranged to pivots about a central axis of the rotatable ratchet. In one form, the central axis is perpendicular to a longitudinal axis of the elongated rod. More preferably, the rotatable ratchet is provided with a series of ratchet ramps equally spaced in a circular arrangement around the central axis. Even more preferably, the ratchet ramps are arranged such that one ratchet ramp coincides to one charge of the charge strip, with rotation of the ratchet by one ratchet ramp corresponding with movement of the strip by one powder charge. 
     Preferably, the rotatable ratchet is mounted to permit tilting of the ratchet, with a central spring biasing the ratchet to an untilted configuration. 
     Preferably, each of the teeth has an involute profile to facilitate meshing with the strip. 
     In a preferred form, the charge advance member is in the form of an arm. More preferably, the arm is fixed to the trigger to move with the trigger as the trigger is pulled by the user. Even more preferably, the arm is arranged to deflect laterally over one ratchet ramp on pulling of the trigger. In one form, the arm has a catch for engaging with said ratchet ramp to drive rotation of the ratchet on return of the trigger. 
     In accordance with another aspect of the present disclosure, there is provided a powder actuated fastening tool including a charge advance apparatus for advancing a powder charge strip relative to a barrel of the tool, wherein the charge advance apparatus includes a rotatable ratchet having teeth for engaging receptacles formed in the powder charge strip, wherein the barrel is slideably mounted between an open position in which the barrel is spaced from the charge and a closed position in which the barrel encloses the charge, wherein the barrel has mounted thereon an alignment member which moves relative to the ratchet when the barrel is brought from the open position to the closed position to ensure a charge is in alignment with the barrel. 
     Preferably, the tool includes a charge advance member coupled to a trigger of the tool, wherein the charge advance member acts upon the rotatable ratchet to rotate the ratchet in response to actuation and/or release of the trigger, such that the rotation of the ratchet causes advance of the powder charge strip. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is described, by way of non-limiting example only, with reference to the accompanying drawings, in which: 
         FIG.  1    shows a perspective view of a partially dismantled tool having a charge advance mechanism in accordance with an example of the present disclosure; 
         FIG.  2    shows a perspective view of the charge advance mechanism; 
         FIG.  3    shows a perspective view of a rotatable ratchet of the charge advance mechanism; 
         FIG.  4    shows a top view of the ratchet; 
         FIG.  5    shows a side view of the ratchet; 
         FIG.  6    shows a bottom view of the ratchet; 
         FIG.  7    shows a perspective view of the charge advance mechanism with the barrel in an open position; 
         FIG.  8    shows a perspective view of the charge advance mechanism with the barrel in a closed position; 
         FIG.  9    shows a perspective view of the charge advance mechanism with the barrel in the closed position and the trigger pulled back; 
         FIG.  10    shows a perspective view of the charge advance mechanism with the barrel in the open position and the trigger driving rotation of the ratchet; 
         FIG.  11    shows a perspective view of the charge advance mechanism with the barrel in the open position and the trigger returned to the rest position; 
         FIG.  12    shows an underside view of a charge advance member coupled to the trigger in a first stage of a deployment cycle of the tool; 
         FIG.  13    shows the charge advance member relative to the ratchet in a second stage of the deployment cycle; 
         FIG.  14    shows a third stage of the deployment cycle; 
         FIG.  15    shows a fourth stage of the deployment cycle; 
         FIGS.  16  to  21    show a side view of the tool in successive steps over a single deployment cycle of the tool, including movement of the barrel, trigger and charge strip; 
         FIGS.  22  to  26    show successive steps in initial loading of the strip into the tool and, in particular, engagement of teeth of the ratchet with the strip; 
         FIG.  27    shows detail of the barrel and ratchet with the barrel in the open position; 
         FIG.  28    shows a rear perspective view of the ratchet and barrel, with the barrel in the closed position; and 
         FIG.  29    shows a front perspective view of the ratchet and barrel, with the barrel in the closed position. 
     
    
    
     DETAILED DESCRIPTION 
     With reference to  FIGS.  1  to  29    of the drawings, there is shown a powder actuated fastening tool  10  having a charge advance apparatus  12  which, advantageously, ensures that a strip of powder charges is accurately and adequately advanced through the tool  10  such that the charges are properly aligned with a barrel of the tool  10  for safe and effective operation of the tool. 
     More specifically, with reference to  FIGS.  1  and  2    of the drawings, the charge advance apparatus  12  is for advancing a powder charge strip  14  relative to a barrel  16  of the tool  10 . The charge advance apparatus  12  includes a rotatable ratchet  18  having teeth  20  for engaging receptacles  22  formed in the powder charge strip  14 . In the example shown, the charge advance apparatus  12  also includes a charge advance member  24 , in the form of a charge advance lever, coupled to a trigger  26  of the tool  10 . The charge advance member  24  acts on the rotatable ratchet  18  to rotate the ratchet  18  (shown in  FIG.  2    in the form of a ratchet wheel) in response to actuation and/or release of the trigger  26 , such that the rotation of the ratchet  18  causes advance of the powder charge strip  14  relative to the section of barrel  16  shown in  FIG.  2   . In  FIG.  1   , the tool  10  is shown in an assembled form without a left hand side housing. As shown in  FIG.  2   , a cantilever spring  25  may be provided for biasing a distal end of the charge advance member  24  toward the rotatable ratchet  18 . 
     Detail of the rotatable ratchet  18  is shown in  FIGS.  3  to  6    of the drawings. With reference to  FIG.  3   , an inner bore of the rotatable ratchet  18  wheel is tapered, having a tapered base  39 , allowing the wheel to pivot, allowing the wheel&#39;s pins to lift out of the way upon insertion of the charge strip  14 .  FIG.  4    shows the rotatable ratchet  18  wheel, showing ramp profile and hexagonal alignment features. Turning to  FIG.  5   , the optimal pin/tooth profile that engages with the charge strip  14  is a modified involute profile in which one side of each pin tip is chamfered, to have a chamfered tooth tip  41 , so as to provide clearance for the charge strip  14 . Replacing the involute pin profile with a circular pin will also function as intended.  FIG.  6    shows the rotatable ratchet  18  wheel with modified involute profile pins/teeth on a reverse face thereof. 
     With reference to  FIGS.  7  to  11   , the barrel  16  has mounted thereon an alignment member  28  (shown in the form of a lockout pin) which moves relative to the rotatable ratchet  18  when the barrel  16  is brought from the open position (see  FIG.  7   ) to the closed position (see  FIG.  8   ) to ensure a charge  30  of the powder charge strip  14  is in alignment with the barrel  16 . When the barrel  16  is brought from the open position to the closed position, the alignment member  28  is moved into abutment with the ratchet  18  to prevent the ratchet  18  from rotating, thereby preventing the charge  30  from moving out of alignment with the barrel  16 . The rotatable ratchet  18  has a plurality of straight sides  32 , such that when the barrel  16  is brought from the open position to the closed position, the alignment member  28  is moved into abutment with one of the straight sides  32 , along the length of the straight side  32 , to prevent rotation of the ratchet  18 . As can be seen from  FIGS.  7  and  8   , the alignment member  28  is moved into abutment with the straight side  32  in a direction parallel to the straight side  32 . In particular, the alignment member  28  is in the form of an elongated rod  34  and the rotatable ratchet  18  is hexagonal in shape. 
     As can also be seen in  FIGS.  7  to  11   , the rotatable ratchet  18  is arranged to pivot about a central axis  36  of the rotatable ratchet  18 . The central axis  36  is perpendicular to a longitudinal axis  38  of the elongated rod  34 . Turning to the detail shown in  FIGS.  3  to  6   , the rotatable ratchet  18  is provided with a series of ratchet ramps  40  equally spaced in a circular arrangement around the central axis, as best seen in  FIG.  4   . The ratchet ramps  40  are arranged such that one ratchet ramp  40  coincides to one charge  30  of the charge strip  14 , with rotation of the ratchet  18  by one ratchet ramp  40  corresponding with movement of the strip  14  by one powder charge  30 . 
     The rotatable ratchet  18  is mounted to permit tilting of the ratchet  18 , and also raising of the ratchet  18  as shown in  FIGS.  24  and  25    of the drawings. Tilting is permitted by virtue of a central spring  42  which biases the ratchet  18  to an untilted configuration, shown most clearly in  FIG.  29    where the rotatable ratchet  18  lies perpendicular to the central axis  36  about which it rotates. 
     As shown in  FIG.  6   , each of the teeth  20  has an involute profile  44  to facilitate meshing of the teeth  20  with the receptacles  22  of the powder charge strip  14 . Tips of the teeth  20  may also be chamfered to facilitate efficient meshing with the powder charge strip  14 . 
     As shown in  FIGS.  7  to  11   , the charge advance member  24  may be in the form of an arm  46  which is fixed to the trigger  26  by way of fasteners  48  such that the arm  46  moves with the trigger  26  as the trigger  26  is pulled by the user. Detail of the arm  46  is shown in  FIGS.  12  to  15   , specifically showing the manner in which the arm  46  cooperates with the rotatable ratchet  18  during pulling back of the trigger in cyclic operation of the powder actuated fastening tool  10 .  FIG.  12    shows the charge advance lever in a home position;  FIG.  13    shows the charge advance lever protrusion engaged with the sawtooth ramp;  FIG.  14    shows the charge advance lever protrusion on top of sawtooth ramp; and  FIG.  15    shows the charge advance lever protrusion advanced over the sawtooth ramp. Specifically, as can be seen in  FIGS.  13  and  14   , the arm  46  is arranged to deflect laterally over one ratchet ramp  40   a  on pulling of the trigger  26  such that the tip of the arm  46  rides upwardly over the ratchet ramp  40   a . The arm  46  also has a catch  50  for engaging with said ratchet ramp  40   a  to drive rotation of the rotatable ratchet  18  on return of the trigger  26 , in the configuration shown in  FIG.  15    in which the arm  46  has ridden over the ratchet ramp  40   a  that the catch  50  engages with an edge of the ratchet ramp  40   a . Also, the trigger  26  may be provided with a degree of free lateral movement or “play” to assist the catch  50  in moving laterally to ride over the ratchet ramp  40   a.    
     Accordingly, as discussed above,  FIGS.  7  to  11    show the process of firing the tool  10  and advancing to the next charge highlighting only the parts required for the charge advance mechanism/system  12 . 
       FIG.  7    shows the tool  10  in the uncocked state;  FIG.  8    shows the tool  10  cocked;  FIG.  9    shows the trigger  26  actuated;  FIG.  10    shows the tool uncocked and the trigger released; and  FIG.  11    shows the tool returned to the uncocked state. Upon cocking the tool  10  by pressing the barrel  16  into the work piece, the lockout pin (which serves as an alignment member and is part of the barrel assembly) rotates the ratchet wheel  18  ensuring the charge strip  14  is correctly aligned ( FIG.  8   ). 
     The ratchet wheel  18  has a number of sawtooth ramp-shaped features  40  on its face, arranged in a circle about the axis of rotation, as shown in  FIG.  3   . The charge advance lever  24  has a protrusion  50  that engages with these ramps  50 , allowing the advance lever  24  to rotate the ratchet wheel  18  in one direction, as shown in  FIGS.  12  to  15   . When the trigger  26  is actuated, the charge advance lever  24  clicks over the sawtooth ramp feature  40   a  of the ratchet wheel  18  with the cantilever spring used to ensure the lever  24  remains engaged with the ramp (see  FIG.  9   ). Slightly after the lever  24  has clicked over the ramp  40   a , the tool  10  will fire. This is due to the operation of the firing mechanism (not shown). 
     Upon uncocking of the barrel  16 , the lockout pin  28  disengages with the ratchet wheel  18  along with the barrel breech disengaging from the charge. At this point, when the trigger  26  is released, the charge advance lever  24  pulls on the vertical face of the ratchet wheel&#39;s ramp  40   a  causing the ratchet wheel  18  to rotate (see  FIG.  10    and  FIG.  11   ). Pins/teeth  20  on the ratchet wheel  18  engage with mating slots/receptacles in the charge strip  14 , acting as rack and pinion gearing. Upon rotation of the ratchet wheel  18 , the charge strip  14  is pulled through the breech by the pins/teeth  20 . The engagement of the pins/teeth with the slots/receptacles in the charge strip  14  is shown in  FIG.  26   . 
       FIGS.  16  to  21    show a side view of the powder actuated fastening tool  10 , progressively depicting steps during cyclic operation of the tool  10 . Specifically, the steps shown include movement of the barrel  16  so as to enable functioning of the tool, firing of the tool while the barrel is in the closed position, opening of the barrel  16 , then release of the trigger  26  so as to advance the powder charge strip  14  by virtue of the charge advance apparatus  12 .  FIG.  16    shows the tool  10  prior to closing the barrel  16 ;  FIG.  17    shows the barrel  16  in the closed position;  FIG.  18    shows the trigger  26  pulled back;  FIG.  19    shows the barrel  16  being returned to the open position;  FIG.  20    shows the trigger  26  during release back toward a rest condition during which movement the rotatable ratchet  18  is driven to move the strip  14  through the tool  10 ; and  FIG.  21    shows the tool  10  with the trigger fully returned to the rest condition and with a new charge ready for the next cycle in which the barrel  16  will be closed over the new charge.  FIG.  16    shows the tool in the uncocked state;  FIG.  17    shows the tool cocked (note that the lockout pin aligns and locks the ratchet wheel);  FIG.  18    shows the trigger actuated (the protrusion on the charge advance lever has clicked over the ramp on the ratchet wheel);  FIG.  19    shows the tool uncocked (the lockout pin has retracted, freeing rotation of the ratchet wheel);  FIG.  20    shows the trigger released (the charge advance lever retracts, rotating the charge advance wheel clockwise, as shown, the charge strip is thereby advanced one slot); and  FIG.  21    shows the tool  10  back in the uncocked state. 
       FIGS.  22  to  26    depict initial insertion of the charge strip  14  into the tool  10 , specifically showing interaction of the charge strip  14  with the rotatable ratchet  18 . Initially, as can be seen, the charge strip  14  may not engage with the rotatable ratchet  18  which, by virtue of the central spring  42 , is able to ride up and over an edge of the charge strip  14  until it engages with the receptacles  22  of the strip  14 , as shown in  FIG.  26   . 
     Accordingly,  FIGS.  22  to  26    show insertion of the charge strip  14 . These drawings show the process of inserting a charge strip into the tool. 
     Due to the first slot in the charge strip  14  having a different pitch to the rest of the strip  14 , a method of enabling the ratchet wheel pins  20  to skip the first slot is required. To achieve this, the ramped surface of the first slot in the charge strip  14  is used to lift the ratchet wheel  18  out of the way until the charge strip  14  has been inserted far enough for the first pin to engage with the slot. 
     Upon strip insertion into the tool  10 , the ramped leading edge of the strip  14  engages with the first pin of the ratchet wheel  18  (see  FIG.  22   ). This causes the ratchet wheel  18  to rotate until the next pin contacts the back of the charge strip  14  (see  FIG.  23   ). As the charge strip  14  is pushed through, the ratchet wheel  18  lifts due to the angled contact with the charge strip  14  (see  FIG.  24   ) until the ratchet wheel&#39;s first pin is above the charge strip slot (see  FIG.  25   ). When the charge strip  14  is pushed further, the ratchet wheel  18  drops down into the first slot in the charge strip  14  and is fully engaged (see  FIG.  26   ).  FIG.  22    shows the strip inserted;  FIG.  23    shows the ratchet wheel  18  engaged;  FIG.  24    shows the ratchet wheel  18  lifting;  FIG.  25    shows the ratchet wheel  18  completely lifted; and  FIG.  26    shows the ratchet engaged in first slot. 
       FIGS.  27  to  29    show perspective views of the barrel  16 , rotatable ratchet  18  and alignment member  28  in the open position ( FIG.  27   ) as well as in the closed position ( FIG.  28    and  FIG.  29   ). In particular,  FIGS.  27  to  29    show detail of the barrel  16 , rotatable ratchet  18  and alignment member  28  showing the manner in which they interact with the powder charge strip  14 . 
     While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments. 
     The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates. 
     Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.