Abstract:
A punch die is provided. The punch die includes a punch body, a punch guide configured to removably receive the punch body therein, a retainer collar detachably coupled to the punch guide, a punch head mated to the punch body to regulate a position of the punch body, and a spring interposed between the punch head and the retainer collar. The punch guide includes a peripheral slot defined on the internal periphery of the punch guide such that the peripheral slot intersects a keyway of the punch guide. The retainer collar includes a cylindrical projection that extends into the inner periphery of the punch guide and an engaging projection defined on an outer periphery of the cylindrical projection. The engaging projection is rotatable to engage the peripheral slot and to be releasably aligned with the keyway.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuation application of pending U.S. patent application Ser. No. 14/764,338, filed on Jul. 29, 2015, which is a U.S. National Stage Application of International Application PCT/JP2014/053841, filed Feb. 19, 2014, which claims priority to Japanese Application No. 2013-038410, filed Feb. 28, 2013. The disclosures of these documents, including the specifications, drawings and claims, are incorporated herein by reference in their entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a punch die, which is attached to a punch holder of a punch press and then used, and in particular relates to a punch die which enables height regulation after sharpening an edge portion of a punch for example, in a state where a punch body fits in a punch body. 
       BACKGROUND ART 
       [0003]    In a punch die which is attached to a punch holder of a punch press such as a turret punch press for example, when an punch edge portion of a punch body of the punch die wears out, it is normal to sharpen the punch edge portion. When the punch edge portion is thus sharpened, as the length size from a punch head to the punch edge portion of the punch die is shortened, a screwing relation between the punch head and the punch body is regulated to regulate the height. (See the PTL 1 for example) 
       CITATION LIST 
     Patent Literature 
       [0000]    
       
         [PTL 1]: Japanese Patent Application Laid-Open No. 2010-23097 
       
     
       SUMMARY OF INVENTION 
       [0005]    The punch die as described in the PTL 1 is comprised of a cylindrical punch guide, in which a punch body having a punch edge portion at its lower end portion fits in such a way as to be movable upward and downward. On an internal periphery of the punch guide provided is a keyway in the vertical direction in which a key formed on the punch body slidably fits. And, on a upper face of the punch guide provided is a retainer collar in such a way as to be rotatable and fixable. Through the retainer collar, a punch driver that the punch body has is made to pass in such a way as to be movable upward and downward, and, between a punch head screwed in an upper end of the punch driver in such a way that its position is regulatable and the retainer collar, a stripper spring is repulsively loaded. 
         [0006]    And, a sleeve that the punch head unitarily comprises passes through the retainer collar in such a way as to be movable only in the vertical direction. Therefore, as the retainer collar is rotated relative to the punch body, the screwing relation between the punch driver and the punch head is made to be regulated. In the punch guide, a cylindrical portion that the retainer collar comprises at its lower portion relatively rotatably fits. 
         [0007]    In order to keep them to be relatively rotatable in a state where the cylindrical portion of the retainer collar fits in the punch guide, and in order to keep the fitting state of the retainer collar relative to the punch guide, a peripheral slot is formed on an upper side of the internal periphery of the punch guide. And, a projection portion that an outer periphery of the cylindrical portion of the retainer collar has fits in this peripheral slot. To engage or detach the projection portion with or from the peripheral slot, a communication slot is particularly formed to communicate the upper face of the punch guide with the peripheral slot. 
         [0008]    Therefore, in the construction described in the PTL1, it is necessary to independently machine the keyway for the key, which the punch body has, and the communication slot for the projection portion. There must be problems in that the number of machining steps is increased and the machining itself is made to be complex. 
         [0009]    The present invention has been achieved in light of the aforementioned problem. 
         [0010]    According to an aspect of the present invention, a punch die is comprised of: a punch body comprising a punch edge portion at a lower end portion along an axis, a key projecting from an outer periphery, and a punch driver at an upper portion along the axis; a punch guide comprising an inner hollow elongated along the axis and receiving the punch body to be movable along the axis, and a keyway formed on an internal periphery of the inner hollow to extend along the axis and mesh with the key; a retainer collar rotatably combined with the punch guide at an upper end along the axis and around the axis, the punch driver passing through the retainer collar to be movable along the axis; a punch head screwed in an upper end portion along the axis of the punch driver to regulate a position of the punch driver; and an elastic member interposed between the punch head and the retainer collar to bias the punch driver upward along the axis, wherein the punch guide comprises a peripheral slot formed on the internal periphery of the inner hollow so as to communicate with the keyway and elongated in a circumferential direction around the axis, and the retainer collar comprises a cylindrical portion fitting in the punch guide and an engaging projection portion formed on an outer periphery of the cylindrical portion and capable of passing through the keyway and engaging with the peripheral slot. 
       ADVANTAGEOUS EFFECTS OF INVENTION 
       [0011]    According to the present invention, the engaging projection portion that the retainer collar has can be passed through the keyway for the key, which the punch body has, and can be engaged with the peripheral slot that the punch guide has. Therefore the construction of the punch guide is made simpler and its machining is made easier. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0012]      FIG. 1  is a longitudinal sectional view of a punch die according to an embodiment of the present invention. 
           [0013]      FIG. 2  is a plan view of a ring member. 
           [0014]      FIG. 3A  is a plan view of a punch guide and a punch body, which shows a state where a key meets a keyway and an engaging projection portion is not aligned therewith. 
           [0015]      FIG. 3B  is a plan view of the punch guide and the punch body, which shows a state where the engaging projection portion is aligned with the keyway. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0016]    Certain exemplary embodiments of the present invention will be described hereinafter with reference to the appended drawings. In the following descriptions, while the term “axis” generally means a central axis of a punch body, axes of a punch guide in which the punch body fits and a punch installation hole in which the punch guide fits are common thereto. Further, while “upper” and “lower” are defined in regard to the axis, this definition is only for the convenience of explanation. Embodiments where the structure is made upside down or the axis is directed horizontally, or any such variations, may be possible. 
         [0017]    Referring to  FIG. 1 , a punch die according to an embodiment of the present invention is attached to a punch holder (corresponding to an upper turret in a case of a turret punch press) of a punch press such as a turret punch press and then used. This punch die  1  is, as with a generally-available punch die, comprised of a cylindrical punch guide  3 , which fits in a punch installation hole formed in the punch holder, thereby being supported to be movable upward and downward. 
         [0018]    In the aforementioned punch guide  3  fitted is a punch body  5  comprising a punch edge portion  5 B at its lower end portion, which is made movable upward and downward along the axis. This punch body  5  is, as with a generally-available punch die, comprised of a key  7  and, as corresponding therewith, the punch guide  3  is comprised of a keyway  9  elongated along the axis on its internal periphery. The key  7  fits in the keyway  9  and is movable upward and downward along the axis. Relative rotation between the punch body  5  and the punch guide  3  is thus restricted. 
         [0019]    With the punch guide  3 , at its upper end along the axis, detachably coupled is a retainer collar  11  of a ring-like shape. The punch body  5  is, unitarily at its upper portion, or as a separate body but fixed thereto, comprised of a punch driver  13 . The punch driver  13  penetrates the retainer collar  11  and is movable along the axis. The punch driver  13  is comprised of a stripper unit  15  at its upper portion. 
         [0020]    In more detail, at its upper end portion along the axis of the punch driver  13  formed is a male screw portion  17 , and the stripper unit  15  is comprised of a punch head  19 , which screws on the male screw portion  17 . The punch head  19  is comprised of a sleeve  21  formed to be elongate downward. On an outer periphery of the sleeve  21  fitted is a spring seat  23 , which is provided on the upper face of the retainer collar  11  in a unitary manner in such a way as to be movable upward and downward along the axis. Between the spring seat  23  and the punch head  19 , an elastic member  25  as a stripper spring is repulsively loaded. In the meantime, the sleeve  21  fits in the spring seat  23  and is movable relative thereto only in directions along the axis, and relative rotation between the spring seat  23  and the sleeve  21  is restricted. And, a stopper  27  such as a snap-ring engaged with a lower end portion or its vicinity of the sleeve  21  prevents the sleeve  21  from getting out. 
         [0021]    The retainer collar  11  is, at its lower face, comprised of a downward-projecting portion  29  of a cylindrical shape, which is capable of fitting on (fitting in) the punch guide  3  from its upper side. The downward-projecting portion  29  is, at a part of its outer periphery, comprised of an engaging projection portion  33 , which is engageable with a circular engaging slot (peripheral slot)  31  formed on the internal periphery of the punch guide  3 . The length of the engaging projection portion  33 , in its circumferential direction, is smaller than the width of the keyway  9  of the punch guide  3 . 
         [0022]    By the aforementioned construction, in a state where the engaging slot  31  engages with the engaging projection portion  33 , the retainer collar  11  is barred (restricted) from getting out upward relative to the punch guide  3 . And, when rotating the retainer collar  11  relative to the punch guide and placing the engaging projection portion  33  at the position of the keyway  9 , the retainer collar  11  is allowed to get upward out of the punch guide  3 . As being understood already, the retainer collar  11  is rotatable relative to the punch guide  3  and also capable of being fixed therewith temporarily. 
         [0023]    In order to temporarily fix the retainer collar  11 , on upper faces of the retainer collar  11  and the punch guide  3  provided is a locking mechanism  35 . The locking mechanism  35  is configured to allow rotation of the retainer collar  11  relative to the punch guide  3  and also temporarily fix the rotation. In more detail, on the upper face of the punch guide  3  combined is a ring member  37  by means of a fastener (not shown) such as a pin or an attachment screw. As shown in  FIG. 2 , the ring member  37  has an inner hollow and its internal diameter  37 R is greater than the internal diameter  3 R of the punch guide  3 . On an internal periphery of the inner hollow formed is a plurality of dent portions  39  getting dented radially outward at proper intervals in its circumferential direction. As having the ring member  37 , a circular opening (an inner hollow of the ring member  37  having the internal diameter  37 R) is opened on the upper face of the punch guide  3 , which is larger in diameter than the internal diameter  3 R of the punch guide  3 . 
         [0024]    The retainer collar  11  is comprised of a guiding slot  41  and a press-button  43  radially slidably engage in the guiding slot  41 . The press-button  43  is comprised of an engaging portion  45  projecting downward from its lower portion in a way as to be engageable with the plurality of dent portions  39  formed on the ring member  37 . The engaging portion  45  is engageable with any of the plurality of dent portions  39 . Between the retainer collar  11  or the spring seat  23  and the press-button  43  repulsively loaded is an elastic member (not shown) such as a coil spring, thereby steadily biasing the press-button  43  radially outward. 
         [0025]    The engaging portion  45  of the press-button  43  is, as being biased radially outward, set in a state of engaging with any of the dent portions  39  of the ring member  37 . Therefore, in a normal state, it is set in a state where rotation of the retainer collar  11  relative to the punch guide  3  is restricted. When pressing the press-button  43  radially inward against the biasing force, the engaging portion  45  is released from the dent portion  39  of the ring member  37  inward, so that the retainer collar  11  is allowed to rotate relative to the punch guide  3 . 
         [0026]    As described above, when releasing the engaging portion  45  inward from the dent portion  39 , the engaging portion  45  takes a position between the internal periphery of the ring member  37  and the internal periphery of the punch guide  3 . In other words, the engaging portion  45  takes a position at the outside of the range of upward and downward motion of the sleeve  21  of the punch head  19 . Therefore, supposed that the press-button  43  failed to go back to the initial position by the biasing force, the engaging portion  45  and the sleeve  21  would not interfere, thereby the punch body  5  is movable along the axis relative to the punch guide  3  with no hitch. 
         [0027]    By the way, to attach or detach the punch body  5  to or from the punch guide  3 , it is necessary to press the press-button  43  inward against the biasing force and keep the engaging portion  45  of the press-button  43  apart from the dent portion  39  of the ring member  37 . Next the retainer collar  11  is rotated relative to the punch guide  3  and the engaging projection portion  33  provided on the retainer collar  11  is aligned with the keyway  9  of the punch guide  33  in the circumferential direction as shown in  FIG. 3B . 
         [0028]    When the engaging projection portion  33  is aligned with the keyway  9  in the circumferential direction as described above, the key  7  fitting with the punch body  5  is aligned with the engaging projection portion  33  in the circumferential direction. Then the engaging projection portion  33  and the key  7  can pass through the keyway  9  and move upward relative to the punch guide  3 . More specifically, the punch body  5  and the retainer collar  11  can be taken upward out of the punch guide  3 . 
         [0029]    As being understood already, as the key  7  formed on the punch body  5  and the engaging portion  33  formed on the retainer collar  11  are aligned with each other in the circumferential direction, both the key  7  and the retainer collar  11  can pass through the keyway  9  of the punch guide  3 , thereby the punch body  5  and the retainer collar  11  can be attached to or detached from the punch guide  3 . More specifically, disassembly and assembly of the punch die  1  is easy. 
         [0030]    When one is intended to fit the punch body  5  in the punch guide  3  and regulate its height, the whole thereof can be made upside down so as to direct the punch edge portion  5 B of the punch body  5  upward. As the punch edge portion  5 B is directed upward, one can readily get a view of exit or entry of the punch edge portion  5 B relative to the punch body  5 , thereby allowing the height regulation under the vision. Then he or she can hold the stripper unit  15  with the right hand and press the press-button by a finger of the hand. He or she next catches and rotates the punch guide  3  by the left hand. 
         [0031]    As the press-button  43  exists in the retainer collar  11  and the retainer collar  11  is directly above the hand keeping the stripper unit  15 , he or she readily press the press-button  43  with a finger of the same hand. Therefore he or she makes the punch edge portion  5 B upward and gets a view thereof, thereby readily regulating the height. When the punch edge portion  5 B is viewed as described above, the hand to press the press-button  43  comes to the lower side and the punch guide  3  at the upper side is rotated. The punch body  5  is therefore prevented from unintentionally getting downward out of the punch guide  3 . 
         [0032]    When rotating the punch guide  3  relative to the punch body  5 , as shown in  FIG. 3A , as the keyway  9  is not aligned with the position of the engaging projection portion  33  in the circumferential direction, the engaging projection portion  33  gets engaged with the peripheral slot  31 . Therefore even in a case where the hand holding the stripper unit  15  is unintentionally detached therefrom, the punch body  5  keeps in place in the punch guide  3  and is therefore prevented from getting out. 
         [0033]    As being understood from the above explanation, the press-button  43  constituting the locking mechanism  35  is provided on the retainer collar  11 . Therefore, it is easy and safe to regulate the height with making the lower end portion of the punch die  1  upward to get a view of exit and entry of the punch edge portion  5 B of the punch body  5 . 
         [0034]    Further, in the construction as described above, the engaging projection portion  33  of the retainer collar  11 , in common with the key  7  of the punch body  5 , has a construction to pass through the keyway  9  of the punch guide  3  in the upward and downward directions. Therefore it is unnecessary to form a passing slot on the punch guide particularly for the engaging projection portion  33 . Thus the construction of the punch guide  3  can be made simpler and machining thereof is made easier. 
         [0035]    Further, when one is intended to attach or detach the punch body  5  and the retainer collar  11  to or from the punch guide  3 , he or she aligns the key  7  of the punch body  5  with the engaging projection portion  33  of the retainer collar  11 . He or she next disengages the engaging projection portion  33  of the key  7  from the keyway  9  of the punch guide  3  simultaneously. Therefore it is easy to attach or detach the punch body  5  and the retainer collar  11  to or from the punch guide  3 . 
         [0036]    In the above descriptions, the dent portions  39  are formed on the ring member  37  which the upper face of the punch guide  3  comprises. The circular opening may be directly formed on the upper face of the punch guide  3  and the dent portions  39  may be formed on the internal periphery of the circular opening. 
         [0037]    Further, the descriptions exemplify a case where the press-button  43  of the locking mechanism  35  is radially movable. The press-button may be, however, instead movable in the axial direction or in the circumferential direction. More specifically, it is possible to engage or disengage the engaging portion  45  with or from the dent portion  39  by moving the press-button in the axial direction or in the circumferential direction. 
         [0038]    Although the invention has been described above by reference to certain embodiments of the invention, the invention is not limited to the embodiments described above. Modifications and variations of the embodiments described above will occur to those skilled in the art, in light of the above teachings. 
       INDUSTRIAL APPLICABILITY 
       [0039]    A punch die by which a punch body does not readily fall down is provided.