Patent Publication Number: US-6655250-B1

Title: Punching apparatus

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a punching apparatus which punches a hole at a predetermined location by means of a punch and a die. 
     2. Background Art 
     There is a type of punching apparatus, in which the punch and the die are in the form of non-circular (for example, quadrangle) cross-section. 
     Conventionally, the problem has been encountered that since the conventional punching apparatus is constructed such that the punch and the die are permanently arranged (static setting) at predetermined locations, a work or an item to be punched must be set so as to coincide with the setting condition of the punch and the die. 
     Now, sometimes it becomes necessary to rotate the work when setting the work so as to coincide with the setting conditions of the punch and the die. In some cases, however, it becomes impossible to punch a non-circular hole, since the rotation range of the work is restricted. 
     SUMMARY OF THE INVENTION 
     It is therefore an objective of the present invention to provide a punching apparatus capable of punching a hole by means of a punch and a die both having non-circular cross-sections. 
     According to the first aspect of the present invention, in a punching apparatus for punching a hole having a non-circular cross section at a predetermined location on a work by means of a punch and a die, the punch and the die are constituted such that the punch is rotatable relative to the punch supporting portion about the central axis line of the punching direction and fixable at a rotational position around the central axis line of punching direction; and, similar to said punch, said die is rotatable about the central axis line of the punching direction with the same rotational phase as that of said punch, and is fixable at a rotational position around the central axis line of the punching direction. 
     The above described punching apparatus is constituted such that a supporting portion of said work is movable in two horizontal directions in a plane which crosses the punching direction at an approximately right angle and is swingable about a base point; a connecting means is provided for integrally connecting said punch and said die in order to rotate both said punch and said die at an identical rotational phase; and it is also possible to adopt an detachable connecting means for integrally connecting said punch and said die in order to rotate both said punch and said die at an identical rotational phase. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagram showing a front view of a punching apparatus according to one embodiment of the present invention. 
     FIG. 2 is a diagram showing a plan view of a punching apparatus shown in FIG.  1 . 
     FIG. 3 is a partially sectioned diagram showing the puncher portion shown in FIG. 2 assembled with a punch pin and a die unit by a connecting pin. 
     FIG. 4 is a diagram showing a plan view of a punch holder shown in FIGS. 2 and 3. 
     FIG. 5 is a diagram showing a bottom view of the punch unit (in which the spring unit, a bush, and a work presser foot are removed) shown in FIG.  3 . 
     FIG. 6 is a diagram showing a plan view of the die unit. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, one embodiment of the present invention is described with reference to the attached drawings. A punching apparatus shown in FIGS. 1 and 2 is suitable for the punch machining of sheet type works for multiple product and small quantity production. The punching apparatus comprises a work supporting portion  10  (not shown in FIG. 1) for supporting a work (not shown), a puncher portion  20 , and an image pickup portion  30 . 
     The work supporting portion  10  is used for supporting by clamping at a predetermined location and is mounted on the upper movable carriage  11  through a θ-direction transfer mechanism  12  so as to be able to swing in the angular direction horizontally about a base center point P. The upper movable carriage  11  is disposed on a machine base  16  through an X-axis direction transfer mechanism  13 , a intermediate movable carriage  14 , and Y-axis direction transfer mechanism  15  so as to be movable in two directions (X-axis direction and Y-axis direction). 
     The θ-direction transfer mechanism  12  comprises a supporting axis  12   a  attached suspended under the work supporting portion  10  and a servo motor  12   b  for driving rotation of the supporting axis  12   a . The θ-direction transfer mechanism  12  is capable of driving or stopping the work supporting portion  10  at an arbitrary angle about the base center point. 
     The X-axis direction transfer mechanism  13  comprises a pair of guide rails  13   a , mounted on the intermediate movable carriage  14  for supporting the upper movable carriage  11  slidably in the X-axis direction, a screw feed mechanism  13   b  disposed between both guide rails  13   a  for feeding the upper movable carrier  11  in the X-axis direction, and a servo-motor  13   c  for driving rotation of a lead screw of the screw feed mechanism  13   b  at one end, such that the upper movable carrier  11  can be moved and stopped at a desired position in the X-axis direction by controlling the rotation of the servo-motor  13   c  by means of a controller (not shown). 
     The Y-axis direction transfer mechanism  15  comprises a pair of guide rails  15   a  mounted on a machine base  16  for supporting the intermediate movable carrier  14  slidably in the Y-axis direction, a screw feed mechanism  15   b  disposed between both rails for transferring the intermediate movable carriage  14  in the Y-axis direction, and a servo-motor for driving rotation of a lead-screw of the screw feed mechanism  15   b , such that the intermediate movable carrier  11  can be moved and stopped at a desired position in the Y-axis direction by controlling the rotation of the servo-motor  15   c  by means of a controller (not shown). 
     The puncher portion  20  is a portion for executing non-circular hole punching (in particular, the quadrangle). As shown in FIGS. 1,  3 , and  4 , the puncher portion comprises a punch holder  24  and a die holder  25 . The punch holder  24  is integrated with one end of a rod  22  (not rotatable), which moves up and down by a hoisting device, using three bolts  23 , and has four slot holes  24   a  in the form of circular arc around a periphery of the rod  22 . The die holder  25  is disposed facing the punch holder  24  on the machine base  16 . As shown in FIG. 3, a punch unit  26  is attached to the punch holder  24  so as to rotate about the central axis line L of the punching direction (vertical direction) and also can be integrally fixed at a desired position in the punching direction. A die unit  27  is attached to the die holder  25  so as to rotate about the central axis line L of the punching direction and can be integrally fixed at a desired position in the punching direction. 
     As shown in FIGS. 3 to  5 , the punch unit  26  comprises, an approximately circular base plate  26   b , integrated with the punch holder  24  by means of six fastening fixing bolts  26   a  which are inserted and screwed through the slot hole  24   a  of the non-rotatable punch holder  24 . A rectangular support plate  26   d  is integrated with the base plate  26   b  by means of four fixing bolts  26   c . A punch  26   g  with a quadrangle cross-section is integrated with the support plate  26   d  by means of two screws  26   e  and two washers  26   f ; and a work presser foot  26   k  is integrated so as to be movable vertically (movable upward from the position shown in FIG. 3) by means of four sets of spring units  26   h , four guide pins  26   i , and bushings  26   j.    
     The upper end of the guide pin  26   i  is fastened to the base plate  26   b , and the lower end of the guide pin supports the work presser foot  26   k  slidably in the vertical direction. Each bushing  26   j  is attached to the work presser foot  26   k  and each bushing  26   j  helps smooth sliding of the guide pin  26   i . Each spring unit  26   h  comprises a pin  26   h   1  which is integrated with the work presser foot  26   k  and which engages with the base plate  26   b  detachably in the upward direction; and a compression coil spring  26   h   2  disposed around the pin  26   h   2  between the base plate  26   b  and the work presser foot  26   k . Here, the spring unit, the bushing  26   j , and the work presser foot  26   k are shown only in FIG.  3 . 
     The upper end of the guide pin  26   i  is fastened to the base plate  26   b , and the lower end of the guide pin supports the work presser foot  26   k  slidably in the vertical direction. Each bush  26   j  is attached to the work presser foot  26   k  and each bush  26   j  helps smooth sliding of the guide pin  26   i . Each spring unit  26   h  comprises a pin  26   h   1  which is integrated with the work presser foot  26   k  and which engages with the base plate  26   b  detachably in the upward direction; and a compression coil spring  26   h   2  disposed around the pin  26   h   2  between the base plate  26   b  and the work presser foot  26   k . Here, the spring unit, the bush  26   j , and the work presser foot  26   k  are shown only in FIG.  3 . 
     As shown in FIGS. 3 and 6, the die unit  27  comprises a base plate  27   b  integrated with the die holder  25  having a fixed relationship with the body of the present apparatus by means of four unit presser foots  27   a . A rectangular support plate  27   e  is integrated with the base plate  27   b  by means of four fixing bolts and two pins  27   d . A die  27   h , having a quadrangular hole in which the punch  26   g  can be inserted to a predetermined depth, is integrated with the support plate  27   e  by means of two screws  27   f  and washers  27   g . A circular die cover  27   j  is integrated with the support plate  27   e  by means of two fixing bolts  27   i . Each unit presser foot  27   a  comprises a block  27   a   1  having a claw portion at the upper portion for engaging with the support plate  27   e , a pin  27   a   2  for fixing the block  27   a   1  at a home position and a pair of fixation bolts  27   a   3 . 
     As shown in FIG. 3, in the present embodiment, the base plate  26   b  of the punch unit  26  and the base plate  27   b  of the die unit  27  are connected through four connecting pins  28  and a pair of up and down bushings  29  (fixed at each base plate) such that the punch  26   g  and the die  27   h  can be rotated integrally in the same rotational phase (in the state that the punch  26   g  can accurately interfit the hole  27   h   1  of the die  27   h ). Each connecting pin  28  is fitted with each bushing  29  so as to be able to be inserted into or drawn out from each bushing. Each connecting pin  28  can attach to or detach from when they set each other at a given distance. 
     In the present embodiment, therefore, the punch unit  26  and the die unit  27 , integrally connected by the connecting pin  28 , can be integrally rotated about the central axis line L of the punching direction (vertical direction), by unfastening six fixing bolts  26   a  (or by detaching, if necessary) in the punch unit  26 , and by unfastening eight fixation bolts  27   a   3  in the die unit  27 . In contrast, the punch unit  26  and the die unit  27 , integrally connected by the connecting pin  28 , are not rotatably fixed at a desired rotational position when the six fixing bolts  26   a  of the punch unit  26  and the eight fixation bolts  27   a   3  of the die unit  27  are tightened. 
     The image pickup portion  30 , used for detecting the displaced amount of the work from the reference location (for detecting the displaced amounts of the work in the X-axis, Y-axis, and the θ directions), provides a camera  31  for outputting analog image signals to an image processing controller (not shown). The image processing controller obtains the locations of two points marked on the work through the image analysis of the image signals, calculates each locational displacement in respective X, Y and θ directions, and outputs these displacements to a monitor (not shown). Furthermore, the displacements of the work can be compensated using the θ direction transfer mechanism  12 , the X direction transfer mechanism  13 , and the Y direction transfer mechanism  15  for restoring the work to the home position (to make the displacement in each direction zero). It is to be noted that the compensation of the displacements can be carried out by an automated operation. 
     The thus constructed punching apparatus according to the present embodiment is capable of providing the steps of compensating the work location, in the state that the punch unit  26  and the die unit  27  are set into the predetermined positions (the connecting pin is removed in this state), into the home position prior to the punching operation by use of the θ direction transfer mechanism  12 , the X direction transfer mechanism  13 , and the Y direction transfer mechanism  15 , and moving the work to a punching position by use of the θ direction transfer mechanism  12 , the X direction transfer mechanism  13 , and the Y direction transfer mechanism  15 , and carrying out the punching operation by means of the punch  26   g  and the die  27   h  (when a plurality of holes are to be punched, the punching operations are carried out in sequence). When the punching operation is to be carried out for a predetermined number of works, the above procedure is repeatedly executed. It is noted in this case, however, if the automated work supply and delivery can be carried out with high accuracy, the compensation operation of the work to the home position can be omitted. 
     In the punching apparatus according to the present embodiment, it is possible to punch a quadrangular hole at a desired location using the punch  26   g  and the die  27   h  by a series of following operational steps at the time of setting the punching unit  26  and the die unit  27 : (1) unfastening the six fixing bolts  26   a  of the punch unit  26  (detaching these bolts if necessary) and unfastening the fixation bolts  27   a   3  of the die unit  27 ; (2) lowering the punch unit so as to integrally connect the punch unit  26  and the die unit  27  by the connecting pin  28 ; (3) integrally rotating the punch unit  26  and the die unit  27  integrally connected by the connecting pin  28  about the centeral axis line of the punching direction (vertical direction) to a desired position; (4) tightening the six fixing bolts  26   a  of the punching unit  26  and tightening the eight fixation bolts  27   a   3  of the die unit  27 ; (5) raising the punch unit  26  so as to remove the connecting pin  28  from the punch unit  26  and the die unit  27 . 
     To sum up, since the punching apparatus according to the present embodiment is capable of fixing the punch  26   g  and the die  27   h  at a desired position by rotating the punch  26   g  and the die  27   h  about the central axis line of the punching direction, it is possible to increase the degree of freedom in setting the punch  26   g  and the die  27   h  and to punch the quadrangular hole at a desired position, even when the rotational range in setting the work is restricted. 
     Furthermore, the work supporting portion  10  are constructed so as to be transferred in a horizontal plane into two directions (X and Y directions) by the X direction transfer mechanism  13  and the Y direction transfer mechanism  15 , and so as to be swingable in the angular direction about the base center point P by the θ direction transfer mechanism  12 . 
     Furthermore, the connecting pin  28  adopted for connecting the punch  26   g  and the die  27   h  allows integral rotation of both the punch  26   g  and the die  27   h , easy setting of the punch  26   g  and the die  27   h  before punching, and reduction of the time for the setting operation, which are effective for punching a variety of quadrangular holes in works with multiple types but small quantities. In addition, since the connecting pin  28  is attachable and detachable for both the punch  26   g  and the die  27   h , it becomes possible to detach the connecting pin from both punch  26   g  and the die  27   h . The connecting pin  28  does not disturb the punching operation and assists an easy punching operation for the work. 
     In the above embodiment, it is provided that the punch  26   g  and the die  27   h  can be rotated in any arbitrary direction. However, it is possible to set the rotational range of the punch  26   g  and the die  27   h  in a small restricted angular range such as 10 degrees or 20 degrees. In the above description, the image pickup portion  30  is used for detecting the location of the work supported by the work supporting portion  10 . However, it should be understood that the other device can be used by replacing the image pickup portion  30  with the other sensor (such as a sensor for detecting the rotation of the supporting axis  12   a  in the θ direction transfer mechanism  12 ). 
     In the above embodiment, a simple and a low cost construction of the punch  26   g  and the die  27   h  by the connecting pin  28  is adopted, but it is possible to replace the connecting pin  28  with other connecting member (if the connecting member is attachable to and detachable from both of the punch  26   g  and the die  27   h , irrespective of their being monolithic or complex bodies. 
     In the above embodiment, although the punch unit  26  and the die unit  27  are manually rotated after being integrally connected by the connecting pin  28 , alternative methods may be used such that the punch unit  26  and the die unit  27  are manually rotated individually, or such that the punch unit  26  and the die unit  27  are respectively rotated by actuators (in this case, it is also possible to detect respective rotations of the punch unit  26  and the die unit  27  in order to improve the operability by controlling the actuation of the actuators by a control unit such that the punch unit  26  and the die unit  27  are in the same rotational phase). 
     In the above embodiment, the punching apparatus is constructed such that the punching unit  26  is fixed by the six fixing bolts  26   a  and the die unit  27  is fixed by the eight fixation bolts  27   a   3 . However, an alternative can be adopted in which the punch unit  26  and the die unit  27  are separately fixed and capable of being clamped and released by respective chucks driven by actuators. In this case, it is preferable to construct the chuck mechanism so as not be released at the time of the punching operation.