Patent Publication Number: US-11034046-B2

Title: Adjustable punch head assembly

Description:
FIELD OF THE INVENTION 
     The present invention relates to a punch head assembly for a punching tool. More specifically, the present invention relates to a punch head assembly that is adjustable, thereby allowing adjustment of the length of the punching tool. 
     BACKGROUND OF THE INVENTION 
     Punching tools are typically used for creating different sizes and shapes of indentations or cuts in a workpiece, such as sheet metal. Punching tools often wear down from use, however, and thus either re-machining or replacement of the tool is required. 
     A need exists for a punch head assembly for a punching tool that is adjustable to allow easy in-field adjustment of the length of the punching tool, thereby avoiding re-machining or replacement of the tool. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention may provide a punch head assembly that comprises a punch head that includes a main body that has opposite first and second ends, and a longitudinal inner bore that extends between the first and second ends. The main body has at least one first passageway that extends substantially radially from the inner bore, and at least one second passageway substantially traversing the first passageway. A ball bearing is receivable in the first passageway. A pin member is receivable in the second passageway for engaging the ball bearing. The pin member is rotationally movable between first and second positions with respect to a longitudinal axis of the second passageway. A driver is coupled to the punch head. The driver includes a stem extending through the second end of the punch head and into the inner bore. At least a portion of the stem has an outer ball engagement surface. The punch head is axially movable with respect to the stem of the driver. Axial movement of the pin member in the second passageway moves the ball bearing into and out of engagement with the outer ball engagement surface of the driver for adjusting an axial position of the punch head with respect to the driver. 
     The present invention may also provide a punch head assembly that comprises a punch head that includes a main body that has opposite first and second ends, and a longitudinal inner bore extending between the first and second ends. A driver is coupled to the punch head. The driver has a base and a stem that extends from the base. The stem extends into the inner bore of the punch head. The punch head is axially movable with respect to the driver. Means for adjusting an axial position of the punch head with respect to the stem of the driver is provided. 
     The present invention may yet further provide a method of adjusting a punch head assembly that has a punch head coupled to a driver and the punch head has a ball bearing received in a first passageway and a pin member received in a second passageway, comprising the steps of pushing the pin member into the second passageway to move the ball bearing from a ball securing portion of a working channel of the pin member to a ball receiving portion of the working channel; adjusting the punch head axially with respect to the driver to establish an axial position of the punch head; and releasing the pin member to force the ball bearing into the ball receiving portion of the working channel such that ball bearing engages the driver, thereby locking the axial position of the punch head. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing figures: 
         FIG. 1  is an exploded perspective view of a punch head assembly according to an exemplary embodiment of the present invention, showing the punch head assembly with components of a punching tool; 
         FIG. 2  is side elevational view of the punch head assembly illustrated in  FIG. 1 ; showing the punch head assembly coupled to the components of the punching tool; 
         FIG. 3  is cross-sectional view of  FIG. 2 ; 
         FIGS. 4 a -4 d    are various views of a pin member of the punch head assembly illustrated in  FIG. 1 ; 
         FIG. 5  is a top plan view with a partial cut away of the punch head assembly illustrated in  FIG. 1 , showing the pin member and associated ball bearing in a disengaged position; and 
         FIG. 6  is similar to  FIG. 5 , except it shows the pin member and ball bearing in an engaged position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1-6 , the present invention relates to a punch head assembly  100  for a punching tool  10  that is designed to allow easy in-field adjustment of the length of the punching tool  10  as the tool wears down. The punch head assembly  100  according to an exemplary embodiment of the present invention generally includes a punch head  102  coupled to a driver  104  and an adjustment mechanism for adjusting the axial position of the punch head  102 , that is the distance between punch head  102  and driver  104 . That adjustment in the axial position of punch head  102  provides for adjustment in the length of the punching tool  10 . 
     As seen in  FIGS. 1-3 , punch head assembly  100  may be coupled to a punch body  12  of the punching tool  10 . Punch body  12  provides a cutting function and may optionally include a spring loaded ejecting member  14  loaded by spring  14   a  therein, which functions to form and eject the part from punch body  12 , as is well known in the art. 
     Punch head  102  generally includes a main body  110  with opposite first and second ends  112  and  114  and a longitudinal inner bore  116  extending between first and second ends  112  and  114 . Inner bore  116  is preferably sized and configured to receive a portion of driver  104 . An end face  118  at first end  112  preferably includes indicia  118   a , such as an etched scale, that provides the operator a gauge for how much the tool  10  is being adjusted. 
     Main body  110  includes a ball bearing passageway  120  that extends substantially radially outward from inner bore  116 . Passageway  120  is open at its outer end  122  to allow insertion of a ball bearing  124  and open at its inner end  125  to allow engagement of ball bearing  124  with driver  104 , as best seen in  FIGS. 5 and 6 . Inner end  125  is preferably sized to trap the ball bearing  124 , thereby preventing the ball bearing  124  from falling through the passageway  120 . Main body  110  also includes a pin passageway  130  that substantially traverses ball bearing passageway  120  to essentially divide the same. Pin passageway  130  is sized and configured to slidably receive a pin member  132  that is spring loaded by spring  134 , as best seen in  FIGS. 5 and 6 . Pin passageway  130  extends in a direction that is substantially transverse to the longitudinal inner bore  116 , as best seen in  FIGS. 1 and 3 . Both passageways  120  and  130  are preferably located at or near the second end  114  of main body  110 . A cutout portion  136  may be provided in main body  110  at second end  114  that is sized to allow access to pin passageway  130  by pin member  132 . 
     Drive  104  includes a base  140  and a stem  142  extending from base  140 . Stem  142  is insertable into the inner bore  116  of punch head  102  through its second end  114 . Punch head  102  is axially movable with respect to stem  142  of driver  104 . In a preferred embodiment, stem  142  and inner bore  116  are threadably engaged. That is, inner bore  116  of punch head  102  may include inner threads  138  that engage outer threads  144  on a portion of stem  142 . This threaded engagement allows punch head  102  to rotate and move axially with respect to the driver&#39;s stem  142  to adjust the axial position of punch head  102 . Stem  142  may also include an outer ball engagement surface  146 , preferably adjacent to outer threads  144 , that cooperates with ball bearing  124  to lock the selected axial position of punch head  102  with respect to driver  104 . Outer ball engagement surface  146  may include, for example, one or more slots  148  sized to receive a portion of ball bearing  124 , as seen in  FIG. 5 . Slots  148  are preferably longitudinally arranged on and extend around the outer surface of stem  142 . In a preferred embodiment, slots  148  extend continuously around the stem  142 . 
     Base  140  of driver  104  couples to punch body  12  of the punching tool  10 . Base  140  may include an inner recessed area  150  sized to receive an end  16  of punch body  12 , as best seen in  FIG. 3 . In a preferred embodiment, the end  16  of punch body  12  has threads  16   a  that engage corresponding threads  150   a  of the driver&#39;s inner recessed area  150 . Fasteners  152 , such as set screws, as seen in  FIG. 2 , may also be used to attach the driver&#39;s base  140  to the end  16  of punch body  12  and prevent any relative movement between driver  104  and punch body  12 . 
     Pin member  132  is shaped and configured to move ball bearing  124  in and out of engagement with one of slots  148  on stem  142  of driver  104  when pin member  132  is moved in pin passageway  130 . As seen in  FIGS. 4 a -4 d   , pin member  132  generally includes a proximal end  160 , a distal end  162 , an installation channel  164 , a working channel  166  spaced from installation channel  164 , and a linking channel  168  that joins installation and working channels  164  and  166 . Distal end  162  is inserted into ball passageway  120  of punch head  102  and proximal end  160  provides a grasping section  161  that allows manipulation of pin member  132  by the operator. Installation and working channels  164  and  166  are preferably spaced from one another by a certain number of degrees α, preferably about 90 to 180 degrees, and more preferably about 135 degrees, as seen in  FIG. 4   d.    
     Installation channel  164  is open at distal end  162  and may extend to about the middle of pin member  132 . Installation channel  164  is sized to at least partially receive ball bearing  124 , thereby allowing pin member  132  to slide into pin passageway  130  past or alongside of ball bearing  124 . Working channel  166  is shaped to receive ball bearing  124  and move the same into engagement with stem  142  of driver  104 . Working channel  166  is not open at either the proximal or distal ends  160  and  162 . Working channel  166  includes a ball receiving portion  170 , a ball securing portion  172 , and a stepped portion  174  therebetween, as best seen in  FIG. 4 c   . Ball receiving portion  170  receives ball bearing  124  from linking channel  168  when pin member  132  is rotated to move ball bearing  124  out of installation channel  164  and into working channel  166 . Stepped portion  174  guides ball bearing  124  into ball securing portion  172 . Ball securing portion  172  secures ball bearing  124  into engagement with slots  148  on the driver&#39;s stem  142 . 
     Punch head assembly  100  is assembled by initially assembling the ball bearing  124 , spring  134 , and pin member  132  with punch head  102 . First, ball bearing  124  is inserted into ball bearing passageway  120  in punch head  102  and to the inner end  125  of passageway  120  such that ball bearing  124  rests at inner end  125 ; next spring  134  may be inserted into pin passageway  130 ; and then pin member  132  may be inserted into pin passageway  130  against the bias of spring  134  with its installation channel  164  facing inward in the direction of ball bearing  124 , thereby allowing pin member  132  to slide axially in pin passageway  130  past or alongside of ball bearing  124 , as best seen in  FIG. 5 . As seen in  FIGS. 5 and 6 , pin passageway  130  extends in a direction that is substantially transverse to the punch head&#39;s longitudinal inner bore, which receives the stem  142 . That is, the longitudinal axis defined by the pin passageway  130  extends in a direction that is substantially transverse to the longitudinal axis defined by the inner bore  116 . 
     Once pin member  132  is inserted into passageway  130 , pin member  132  may be rotated a certain number of degrees, for example 135 degrees, about a longitudinal axis of pin passageway  130  until ball bearing  124  reaches working channel  166 . More specifically, rotation of pin member  132  forces ball bearing  124  into linking channel  168  which extends ball bearing  124  to ball receiving portion  170  of working channel  166 . When pin member  132  is released, the spring  134  pushes pin member  132  in a direction out of the passageway  130  so that stepped portion  174  guides ball bearing  124  into ball securing portion  172  of working channel  166  with a portion of the ball bearing  124  extending into the punch head&#39;s inner bore  116  at the inner end  125  of passageway  120 . Pin member  132  is retained in punch head  102  because ball bearing  124  prevents pin member  132  from coming out of pin passageway  130 . 
     Once the ball bearing  124 , spring  134 , and pin member  132  are assembled with punch head  102 , the pre-assembled punch head  102  may be coupled with driver  104 . To do so, pin member  132  is pushed in against spring  134  to move ball bearing  124  to the ball receiving portion  170  of working channel  166 , thereby allowing unobstructed insertion of stem  142  of driver  104  into inner bore  116  of punch head  102 . Once the stem  142  is inserted into punch head  102 , at least a portion  138  of the inner surface of inner bore  116  and at least a portion  144  of the outer surface of stem  142  are preferably threadably engaged. Pin member  132  may then be released to move the ball bearing  124  back into ball securing portion  172  of working channel  166  such that the ball bearing  124  engages outer ball engagement surface  146  of stem  142 , preferably by engaging one of the slots  148 . 
     The engagement between ball bearing  124  and one of the slots  148  stops rotation and axial movement of punch head  102  with respect to the driver&#39;s stem  142  to lock punch head  102  in a selected axial position. Spring  134  pushes against distal end  162  of pin member  132  to force pin member  132  out of pin passageway  130 . That leaves grasping section  161  of pin member  132  exposed for manipulation by the operator, as seen in  FIG. 6 . 
     To adjust the axial position of punch head  102  with respect to driver  104 , pin member  132  can be pushed into pin passageway  130  until ball bearing  124  is disposed in ball receiving portion  170  of working channel  168 . Because ball receiving portion  170  is deeper than ball securing portion  172  in channel  166 , pushing pin member  132  toward the back of passageway  130  releases ball bearing  124  from engagement with stem  142  and allows ball bearing  124  to move out of ball securing portion  172  and rest in ball receiving portion  170 . Punch head  102  can then be moved axially with respect to driver  104 , such as by rotating punch head  102  via the threads  138 ,  144 , for example, to adjust its axial position. Once the new axial position of punch head  102  is selected, it can be locked in place by releasing pin member  132  in the same manner as described above, allowing ball bearing  124  to fall into slot  148 . 
     While a particular embodiment has been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.