Abstract:
A pneumatically operated stapler that has a single selectively operable adjusting mechanism that is constructed and arranged to be adjusted within a range of leg deflecting positions is disclosed. The stapler includes a staple leg diverting member that is carried by a portable structure for lateral movement into and out of a drive track. Successively driven staples are driven with a selected leg deflection between a minimum deflection and a maximum deflection. The adjusting mechanism is selectively adjusted within the range of positions to adjust the amount of bias of a biasing structure acting on the leg diverting member.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This application relates to staplers or staple driving devices capable of effecting an outward clinch of the staple within the workpiece as it is driven and more particular to such devices capable of being adjustable to selectively effect any amount of leg deflection within a range of leg deflections and/or to selectively effect no significant deflection or a selective amount of outward leg deflection. 
   2. Description of Related Art 
   Staple driving devices of the type herein contemplated are known in the prior art. An essential of all devices of this type, whether adjustable or not, is the provision of a movable staple leg diverting member or anvil which is normally mounted for movement into and out of the drive track. An example of a non-adjustable outward clinching mechanism is disclosed in U.S. Pat. No. 3,807,619, the disclosure of which is hereby incorporated by reference into the present specification. The anvil includes outward clinching surfaces disposed in a position to be engaged by the legs of the staple during the drive stroke of the staple by the staple driving member. The anvil also includes anvil moving surfaces disposed in a position to be engaged by the crown of the staple during the drive stroke of the staple by the staple driving member. The engagement of the anvil moving surfaces functions to move the clinching surfaces of the anvil out of the drive track toward the end of the drive stroke so as to allow the staple crown to pass through the drive track and into the workpiece. 
   One adjustable stapler of the type herein contemplated which is marketed by the owners of the present application achieves adjustability through a range of outward deflections by moving the anvil through a range in the direction of extent of the drive track. See also, U.S. Pat. No. 4,013,206, the disclosure of which is hereby incorporated into the present specification. In the commercially available device, no significant leg deflection is achieved by locking the anvil out of the drive track by a pair of laterally movable set screws provided solely for that purpose. There exists a need for a stapler of the type described in which adjustability as between no significant leg deflection and an adjustable range of leg deflections is achieved by an adjusting mechanism which is simpler in construction, easier to operate and more economical to manufacture than the adjustment mechanisms provided by the prior art. 
   SUMMARY OF THE INVENTION 
   In accordance with the principles of the present invention, this need is supplied by providing a stapler for driving successive staples into a workpiece which comprises a portable structure defining a drive track, a magazine assembly carried by to the portable structure and constructed and arranged to feed successive leading staples from a supply of staples contained within the magazine assembly into the drive track, a staple driving member mounted in the drive track for movement through successive cycles including: (1) a drive stroke during which a leading staple fed into the drive track by the magazine assembly is moved by the staple driving member outwardly of the drive track and into a workpiece, and (2) a return stroke and a staple leg diverting member carried by the portable structure for lateral movement into and out of the drive track. The stapler includes a single selectively operable adjusting mechanism that is constructed and arranged to be adjusted within a range of leg deflection positions wherein successively driven staples are driven with a selected leg deflection between minimum deflection and maximum deflection. 
   Preferably, the adjusting mechanism is selectively adjusted within the range of adjusted positions to adjust the amount of bias of a biasing structure acting on the leg diverting member. 
   Another aspect of the invention is to provide an improved adjustable leg deflecting mechanism which is useful with or without the provision of a no-significant deflection adjustment. In accordance with the principles of the present invention, this aspect is achieved by providing a stapler of the type previously described in which the staple leg diverting member is carried by the portable structure for biased movement laterally into the drive track and movement out of the drive track against the bias thereof, and in which the staple leg diverting member has leg diverting surfaces configured and positioned to divert the legs of a staple being driven by the staple driving member outwardly with respect to one another, and member moving surfaces configured and positioned to ensure that the leg diverting member is out of the drive track before the end of the drive stroke of the staple by the staple driving member. The magnitude of the bias on the staple leg diverting member to move the staple leg diverting member laterally into the drive track determines the extent of outward deflection of the legs of the staple being driven. An adjustment mechanism is also provided for changing the magnitude of the bias on the staple leg diverting member and therefore the extent of outward deflection of the legs of the staple being driven. 
   A further aspect of the invention is to provide an improved leg deflecting mechanism which achieves adjustment between minimum leg deflection and maximum leg deflection wherein the leg deflection can either be adjustable or non-adjustable. In accordance with the principles of the present invention, this aspect is obtained by providing a stapler of the type previously described in which the staple leg diverting member is carried by the portable structure for biased movement laterally into the drive track and movement out of the drive track against the bias thereof. The staple leg diverting member has leg diverting surfaces configured and positioned to divert the legs of a staple being driven by the staple driving member outwardly with respect to one another, and member moving surfaces configured and positioned to move the leg diverting member out of the drive track against the bias thereof. The magnitude of the bias on the staple leg diverting member to move the staple leg diverting member laterally into the drive track determines the extent of the outward deflection of the legs of the staple being driven. The extent is between an minimum deflection and a maximum deflection. 
   These and other aspects, features, and advantages of this invention will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are part of this disclosure and which illustrate, by way of example, the principles of this invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Features of the invention are shown in the drawings, which form part of this original disclosure, in which: 
       FIG. 1  is a vertical sectional view of a stapler embodying the principles of the present invention; 
       FIG. 2  is an enlarged sectional view taken along the line  2 - 2  of  FIG. 1 ; 
       FIG. 3  is an enlarged sectional view taken along the line  3 - 3  of  FIG. 1 ; 
       FIG. 4  is a perspective view of the anvil embodied in the outward clinching mechanism of the present invention; 
       FIG. 5  is a fragmentary elevational view with parts broken away to more clearly illustrate the condition of the outward clinching mechanism of the stapler when in an inoperative position facing upwardly in preparation of driving a staple into a vertical surface of a workpiece; 
       FIG. 6  is a view similar to  FIG. 5  showing the condition of the outward clinching mechanism of the stapler wherein an inoperative position facing downwardly in preparation for driving a staple into a vertical surface of a workpiece; 
       FIG. 7  is a view similar to  FIG. 2 , oriented as in  FIG. 5 , with the outward clinching mechanism adjusted to a no clinch setting showing the position of the parts during an initial driving movement of staple along the drive track; 
       FIG. 8  is a view similar to  FIG. 7  showing the position of the outward clinching mechanism parts during the final driving movement of the staple; 
       FIG. 9  is a view similar to  FIG. 5  with the outward clinching mechanism adjusted to a minimum deflection or flare setting showing the position of the parts during the driving movement of the staple just before the ends of the staple legs have engaged the anvil clinching surfaces; 
       FIG. 10  is a view similar to  FIG. 9  showing the position of the parts at the end of the driving movement; 
       FIG. 11  is a view similar to  FIG. 5  with the outward clinching mechanism in the setting shown in  FIG. 9  showing the outward clinching mechanism parts in a position similar to  FIG. 7 ; 
       FIG. 12  is a view similar to  FIG. 11  showing the position of the outward clinching mechanism parts when the anvil is moved out of the drive track; 
       FIG. 13  is a view similar to  FIG. 12  showing the position of the outward clinching mechanism parts when the anvil is biased to move back toward the anvil; 
       FIG. 14  is a view similar to  FIG. 13  showing the position of the outward clinching mechanism parts at the end of the driving movement; 
       FIG. 15  is a view similar to  FIG. 9  with the outward clinching mechanism in a maximum deflection or flare setting; 
       FIG. 16  is a view similar to  FIG. 15  showing the position of the outward clinching mechanism parts at the end of the driving movement; 
       FIG. 17  is a view similar to  FIG. 2  with the outward clinching mechanism in the setting of  FIG. 5  showing the position of the outward clinching mechanism parts when the anvil is moved out of the drive track; 
       FIG. 18  is a view similar to  FIG. 17  showing the position of the outward clinching mechanism parts when the anvil is biased to move back toward the drive track; 
       FIG. 19  is a view similar to  FIG. 18  showing the position of the outward clinching mechanism parts at the end of the driving movement; and 
       FIG. 20  is an enlarged view of a lower portion of the stapler of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now more particularly to the drawings, there is shown in  FIG. 1  a stapler, generally indicated at  10 , embodying the principles of the present invention. The invention is particularly concerned with the construction and operation of an outward clinching mechanism, generally indicated at  12 , embodied in the stapler  10 . The stapler  10  itself may be of any known configuration. As shown, the stapler  10  is power operated. Such power operation can be of any well known type such as electrical, internal combustion or pneumatic. The stapler  10  as shown in  FIG. 1  is a typical pneumatically powered unit. 
   Specifically, the pneumatically powered stapler  10  shown in  FIG. 1  includes the usual portable housing or frame structure, generally indicated at  14 . The portable structure  14  includes a handle section  16  which is hollow so as to define a pneumatic reservoir  18 . A fitting  20  leads to the reservoir  18  enabling a source of air under pressure (not shown) to be communicated with the reservoir  18 . 
   The reservoir  18  communicates with a manually operable trigger valve assembly  22  which controls the communication of the reservoir to a pilot pressure chamber  24  of a main valve assembly  26 . The main valve assembly  26  is housed within a cap assembly  28 , fixed to the top of a main housing section  30 , integral with and extending generally perpendicular to the handle section  16 , both of which form parts of the portable structure  14 . 
   Mounted within the main housing section  30  is a cylinder  32 , an upper end of which cooperates with the main valve assembly  26  to enable the main valve assembly  26  to function in the usual fashion when in an inoperative position wherein the pilot pressure chamber  24 , under the control of trigger valve assembly  22  in its inoperative position is communicated with the reservoir. When in its inoperative position, the main valve assembly  26  also functions to communicate the open end of the cylinder  32  with atmosphere through the cap assembly  28 . 
   When the trigger valve assembly  22  is manually moved from its inoperative position into an operative position, the pilot pressure chamber  24  is shut off from communication with the reservoir  18  and communicated with atmosphere. The pressure from the reservoir  18  then acts upon the main valve assembly  26  to move it from its inoperative position into an operative position. In its operative position, the main valve assembly  26  functions to shut off the communication of the open upper end of the cylinder  32  with the atmosphere and to allow full peripheral communication thereof with the reservoir  18 . 
   Communication of the reservoir  18  with the open upper end of the cylinder  32  serves to drive a piston  34  slidably mounted within the cylinder  32  through a fastener drive stroke which is completed when the piston  34  engages a shock absorbing bumper  36  mounted in the main housing section  30  below the lower end of the cylinder  32  which is fixed therein. 
   The drive stroke of the piston  34  constitutes one stroke of a two stroke cycle of movement the piston undergoes on a successive basis in accordance with the manual movement of the trigger valve assembly  22 . The other stroke of the piston  34  which constitutes a return stroke is accomplished by a suitable return system  38 . The return system can be of any known type, the return system  38  being of the air plenum chamber type. 
   The drive stroke of the piston  34  serves to move a staple driving element  40  connected therewith through a drive stroke within a drive track  42  formed within a nose piece assembly  44  fixed below the lower end of the main housing section  30  and forming a part of the portable structure  14 . The drive stroke of the staple driving element  40  serves to drive a leading staple from a supply of staples contained within a staple magazine assembly  46  which has been laterally moved into the drive track  42  along a feed track  48  defined by the magazine assembly  46 . 
   The magazine assembly  46 , which is fixed to the nose piece assembly  44  and extends below and is fixed to the handle section  16 , can be of any known type. The magazine assembly  46 , as shown, is a conventional bottom loader capable of handling staples in a stack formation supply. 
   The trigger valve assembly  22  is manually moved from its inoperative position into its operative position by the coordinated movement of a trigger  50  and contact trip assembly  52 , both of which are of any conventional construction so as to require any known coordination to effect operation. 
   The outward clinching mechanism  12  preferably comprises as basic components thereof, a pivoted anvil or clinching member, generally indicated at  54 , shown in perspective in  FIG. 4 , and an anvil bias adjusting assembly, generally indicated at  56 . The anvil bias adjusting assembly  56  serves to impose on the pivoted anvil  54  a force which biases the anvil  54  in a direction toward and into the drive track  42 . The biasing force (1) can be varied within a range corresponding with a range of outward clinch deflections of the staple legs and (2) can be relieved to allow the anvil  54  to be gravity biased corresponding with a no significant outward deflection of the staple legs. In a preferred embodiment of the invention, the anvil bias adjusting assembly  56  includes a single adjusting member  58  preferably in the form of a threaded set screw as shown in the drawings, which can be manually turned with a suitable hand tool into different positions of adjustment so as to achieve both the range of leg outward deflections and the no significant leg deflection recited above. 
   The adjusting set screw  58  is threaded within a threaded aperture formed in a bifurcated mounting member  60  fixedly mounted on a lower forward end portion of a central plate  62 , shown in  FIG. 3 , of the magazine assembly  46 . The central plate  62  constitutes a fixed part of the magazine assembly  46  when it is in its normal operating position. In the bottom loading type of magazine assembly  46  shown, the central plate  62  forms a fixed part of the movable subassembly of the magazine assembly  46  which is normally latched in a fixed position during operation, but which can be unlatched and moved rearwardly to allow for the loading of a new supply of staples in stick form in the feed track  48  through the open bottom after which the movable subassembly is moved back into its normal latched position. 
   As best shown in  FIG. 3 , the bifurcations of the mounting member  60  are disposed on opposite sides of the central magazine plate  62  and secured in position by a pivot pin  64  which also serves to pivotally mount the anvil  54  for movement toward and away from the drive track  42 . 
   As best shown in  FIGS. 3 and 4 , the anvil  54  includes a pair of laterally spaced mounting portions  66  which receive the bifurcations of the mounting member  60  therebetween and are apertured to receive the pivot pin  64  therethrough. 
   The adjusting assembly  56  also includes a yieldable biasing member  68 , preferably in the form of a rubber cylinder as shown in the drawings. The biasing member  68  is positioned below the pivot pin  64  within the mounting member  60  between a surface  70  of the back face of the anvil  54  and an end surface of the adjusting set screw  58 . 
   As shown in  FIG. 4 , the forward face of the anvil  54  is configured to provide a pair of laterally spaced very slightly angled forwardly facing staple leg engaging surfaces  72  and a much more severely angled staple crown engaging surface  74  disposed therebetween. As shown, the crown engaging surface  74  is in the form of a triangle with a T at its apex. This illustration is not intended to be limiting in any way. For example, in some embodiments, the crown engaging surface  74  may be in the form of a triangle, without a T at its apex. The base of the triangle of the crown engaging surface  74  has a width generally equal to the width of the drive track  42  and is disposed at the discharge end of the drive track  42 . The surfaces of the nose piece assembly  44  defining the opposite sides of the outer extremity of the drive track  42  are flared oppositely outwardly, as indicated at  76  in  FIGS. 2 ,  7 ,  8 ,  11 - 14  and  17 - 19 . The base of the crown engaging surface  74  is spaced from the adjacent staple leg engaging surfaces  72  a distance generally equal to the thickness of the staple driving element so as to enter fully into the drive track  42  when the anvil  54  is biased into its operative position, as determined by the engagement of a pair of laterally spaced, forwardly facing, stop surfaces  78  with cooperating rearwardly facing stop surfaces provided on the mounting member  60 . 
   Extending from the converging ends of the triangular portion of the crown engaging surface  74  are a pair of transversely extending clinching surfaces  80  which merge into the leg engaging surfaces  72  along concavely arcuate transitions surfaces  82 . The portions of the transversely extending-clinching surfaces  80  at the base of the triangle of the crown engaging surfaces  74  are disposed in the path of travel of the legs of the staple during the driving movement and constitute the leg engaging clinching surfaces of the anvil  54  which form the outward deflection or flare of the staple when driven. 
   Also shown in the Figures, especially  FIG. 20 , is a chamfer  84  that is located at an outward end, or bottom, of the drive track  42 . The bottom of the crown engaging surface  74  of the anvil  54  engages the chamfer  84  when the anvil  54  is biased into the drive track  42 , as shown in  FIG. 20 . It has been found that providing the chamfer  84  at the outward end of the drive track  42  assists with the movement of the staple as the staple travels through and out of the drive track  42 , especially as the flare of the staple is increased. 
   Operation 
     FIGS. 5-8  illustrate the condition of the outward clinching mechanism  12  when the single adjusting member  58  is adjusted to a no clinch operative position. As can be seen from  FIGS. 5 and 6 , the adjusting member  58  is turned in a counterclockwise direction to an extent which allows the yieldable biasing member  68  to be freely movable between the adjusting member  58  and the anvil  54 . The anvil  54  is actually biased by its own weight when the stapler  10  is oriented in the position shown in  FIG. 5 . The anvil  54  will actually move pivotally about the pivot pin  64  into a position where the entire crown engaging surface  74  is disposed below and out of the drive track of  42 . Since the drive track  42  is clear of any obstruction, the staple can be driven outwardly by the staple driving element  40  during its drive stroke directly into the workpiece without any significant outward deflection or flare being imposed on the legs of the staple, as shown in  FIG. 8 . 
     FIG. 6  illustrates the reverse situation where the stapler  10  is oriented in a position such that the anvil  54  will be gravity biased in a clockwise direction about its pivot pin  64  so as to engage the stop surfaces  78  and dispose the crown engaging surfaces  74  as well as the leg engaging surfaces  72 ,  80  and  82  within the drive track  42 . It will be understood that the driving movement of the staple driving element  40  in a pneumatically operated device, such as the stapler  10  described above, is a very rapid movement and there is a distance of travel that the staple must move before engaging any of the surfaces of the anvil  54  which are disposed in the drive track  42 . Thus, the engagement will be an impact engagement. Since the free ends of the legs of the staple are leading in the drive track  42  during the driving motion, they will engage the leg engaging surfaces  72  initially. These surfaces  72 , while having only a slight incline, are sufficient, when impacted with the anvil  54  under gravity bias, to quickly move the entire anvil  54  including the surfaces  74  and  80  out of the drive track  42 . As soon as the impact force moves all of the surfaces of the anvil  54  out of the drive track  42 , the gravity acting on the anvil  54  tends to bias it so that the surfaces  74  and  80  thereof move back toward the drive track  42 . By this time, however, the legs of the staple have moved into a position which normally would be occupied by the ends of the base of the crown engaging surface  74 . Consequently, instead of the anvil surfaces entering into the drive track  42 , the crown engaging surface  74  will engage the legs of the staple and prevent the entry of the anvil back into the drive track  42 . The ends of the base of the crown engaging surface  74  will remain in biased engagement with the staple legs as the driving action is completed. 
   It will be noted that in the event that the engagement of the free ends of the legs of the staple with the staple leg engaging surfaces  72  is insufficient to move the anvil  54  out of the drive track  42 , the legs of the staple will then engage the arcuate transition surfaces  82  which provide for a somewhat steeper incline insuring that the transversely extending clinching surfaces  80  of the anvil  54  are moved out of the drive track  42  before the free ends of the legs of the staple can move into engagement therewith. A momentary engagement may result in a insignificant outward flare. Consequently, the no clinch position ensures that the staple will be driven into the workpiece with no significant outward flare. This condition is illustrated in  FIGS. 7 and 8 . 
   It should be noted that the adjusting assembly of  56  in this position still provides a bias on the anvil  54 . The bias is a gravity bias so that when the stapler  10  is in the orientation shown in  FIG. 5 , the bias is a negative bias whereas when the stapler  10  is in an orientation such as shown in  FIG. 6 , the bias is simply a positive gravity bias. It will be understood that while the single adjusting member  58  and yieldable biasing member  68  are shown as being separate from one another and from the anvil  54 , they could be interconnected to provide for unitary linear movement while permitting relative rotational movement either between the single adjusting member  58  and the yieldable biasing member  68  or between the two of them and the anvil  54 . With this modification, which is within the contemplation of the present invention, the movement of the single adjusting member  58  into the no clinch position would hold the surfaces  72  and  74  of the anvil  54  out of the drive track  42  at all times, thus providing a zero bias. 
     FIGS. 9-14  illustrate the condition of the outward clinching mechanism  12  when the single adjusting member  58  is moved into a minimal outward deflection position or at the less severe range of outward deflections provided by the adjusting assembly  56 . As best shown in  FIG. 9 , in this position, the single adjusting member  58  has been turned inwardly to cause the yieldable biasing member  58  to engage the surface  70  of the anvil  54  and move the stop surfaces  78  into engagement and the surfaces  72 ,  74 ,  80  and  82  of the anvil  54  into the drive track  42 . As shown, there is a slight compression of the yieldable biasing member  68  retaining the anvil member  54  in that position. In this condition, when the free ends of the legs of the staple initially engage the staple leg engaging surfaces  72  and then the arcuate transition surfaces  82 , there is insufficient impact force created to move the ends of the transversely extending clinching surfaces  80  and crown engaging surface  74  out of the drive track  42 . Consequently, as the free ends of the legs of the staple move past the arcuate transition surfaces  82 , they will next engage the transversely extending clinching surfaces  80  causing the free ends to flare outwardly, which movement is permitted by the flared drive track surfaces  76 . 
   As the staple continues to move, the engagement of the surfaces  80  with the legs of the staple effect a continued outward flare or deflection thereto until the crown of the staple moves into engagement with the initial portion of the crown engaging surface  74 . The impact of the engagement of the staple crown with the surface  74  is sufficient to overcome the bias of the yieldable biasing member  68  causing the surfaces  74  and  80  of the anvil  54  to move out of the drive track  42 . This movement disengages the transversely extending clinching surfaces  80  from the legs of the staple, thereby ending the outward deflection imparted thereto. As soon as the anvil  54  moves out of the drive track  42 , the yieldable biasing member  68  tends to bias the anvil  54  back toward the drive track  42 . However, by the time this bias can be effective, the legs of the staple have moved into a position to be engaged by the ends of the base of the crown engaging surface  74 . As before, the anvil  42  remains out of the drive track  42  for the remainder of the driving movement of the staple. 
     FIG. 11  illustrates the initial engagement of the free ends of the legs of the staple with the clinching surfaces  80 .  FIG. 12  illustrates the position of the parts just before the anvil  54  is moved out of the drive track  42 .  FIG. 13  illustrates the position of the parts when the staple is moved to block the anvil  54  from entering the drive track  42 .  FIG. 14  illustrates the final drive position of the staple in the minimum adjustment position described. 
     FIGS. 15-19  illustrate the condition of the outward clinching mechanism  12 , when the single adjusting member  58  has been moved fully into a maximum deflection or most severe flare position. As shown in  FIG. 15 , the yieldable biasing member  68  has been compressed even more than the compression shown in  FIG. 8 , imposing a greater resistance force to the movement of the anvil  54  than previously described. In the operation at this position, the outward deflection of the staple begins and takes place in the same manner as before. However, in order to overcome the greater force applied to the anvil, a greater amount of movement of the crown of the staple along the crown-engaging surface  74  must take place before a sufficient impact force is created to overcome the greater biasing force being applied to the anvil  54  by the yieldable biasing member  68 . In this way, the extent of the outward deflection of the legs of the staple is increased to a maximum and the anvil  54  and the surfaces  74  and  80  of the anvil are not moved out of the drive track  42  except at the very end of the driving movement.  FIG. 17  illustrates the position at which the anvil  54  is moved out of the drive track  42 .  FIG. 18  illustrates the position when the anvil  54  is blocked from moving back into the drive track  42  and  FIG. 19  illustrates the final drive. 
   While preferred embodiments of the invention have been shown and described, they are not intended to be limiting in any respect. To the contrary, the invention is intended to encompass all variations and modifications within the spirit and scope of the appended claims.