Patent Publication Number: US-6711977-B2

Title: Portable plate circular arc punch shear structure

Description:
BACKGROUND OF THE INVENTION 
     (a) Field of the Invention 
     The present invention relates to an improved structure for a portable plate circular arc punch shear, and more particularly, to one that allows easy conversion of dies, improved agility and reduced costs of diversified production of smaller quantity. 
     (b) Description of the Prior Art 
     Conventionally, a punch is generally used to drive a die of circular arc shear in fixed dimension for plate circular arc shear. The die takes advantage of the power from the punch to complete the shear process. However, longer punch travel is required for the punch to adapt to other processing conditions, and one die is provided with a single punch dimension only. The fixed design of the die is more complicate, involving high production cost, and difficulties in assembly and dies replacement. Such structure of dies in fixed dimension driven by a punch is not ideal for diversified production of smaller quantity, therefore, is poor in production agility. 
     Furthermore, most of conventional presses or punches, disregarding its type or form are prevented from being portable, and the circular arc shear process for various types of plates requires to be done at a fixed site, resulting in the absence of convenience in their applications. 
     SUMMARY OF THE INVENTION 
     The primary purpose of the present invention is to provide an improved structure of a portable plate circular arc punch shear that allows easy conversion of dies, improved agility, and reduced cost of diversified production of smaller quantity. To attain the purpose, a driver connected to an external pneumatic system is provided to the punch shear and the driver is used to activate a press plate, which in turn, drives a punch shear die provided at its peripheral multiple shear arc areas depending on requirements of individual process. 
     The foregoing object and summary provide only a brief introduction to the present invention. To fully appreciate these and other objects of the present invention as well as the invention itself, all of which will become apparent to those skilled in the art, the following detailed description of the invention and the claims should be read in conjunction with the accompanying drawings. Throughout the specification and drawings identical reference numerals refer to identical or similar parts. 
     Many other advantages and features of the present invention will become manifest to those versed in the art upon making reference to the detailed description and the accompanying sheets of drawings in which a preferred structural embodiment incorporating the principles of the present invention is shown by way of illustrative example. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of a preferred embodiment of the present invention. 
     FIG. 2 illustrates the appearance of the preferred embodiment of the present invention. 
     FIG. 3 is an exploded view of punch shear dies of the preferred embodiment of the present invention. 
     FIG. 4 is a view showing the structure of the punch shear dies assembly in relation to other parts of the preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 through 4 of the accompanying drawings, a preferred embodiment of the present invention is essentially comprised of a main frame  1 , a primary support  2 , a driver  3 , and a punch shear dies unit  4 . The top of the main frame  1  is provided to accommodate other elements, and a housing  11  to cover the main frame  1 . A handle  111  is provided on top of the housing  11 , and multiple bores  12  are provided on the peripheral of the main frame  1  and matching screw eyes  113  are provided on the bottom of the housing  11 . The primary support  2  provided at one end of the main frame  1  has at its bottom a space  21  to accommodate a waste collection bin  22 . A screw eye  211  is provided on top of the accommodation space  21  to receive a fixing bolt  221  provided in relation to said screw eye  211  to fix the waste collection bin  22 . A plunger holder  23  laterally provided on top of the primary support  2  has a plunger  24  vertically penetrating through the center of the plunger holder  23 . A press plate  25  is pivotally mounted on the plunger holder  23 . One end of the press plate  25  is restricted by said plunger  24  and the other end extending to the other side of the main frame  1 . The middle section of the primary support  2  is to accommodate and secure the punch shear dies unit  4  in position. The driver  3  provided on the other side opposite to the primary support  2  of the main frame has its top protruding and holding against one end of the press plate  25 , and has on its die provided with air connectors  31 ,  32  connected to an air control valve  33  via a air pipe. Operation of said air control valve  33  is controlled by pull  331  extending upward. When the pull  331  is pressed, the air valve  33  will drive the driver  3  to lift an end of the press plate  25  thereby depressing the lower end of the press plate  25  and therefore pushing down the upper die  44  to perform cutting operation. Said punch shear dies unit is essentially comprised of a die holder  41 , a lower die  42 , a guide post  43  and an upper die  44 . An accommodation hole  411  is provided in the center of the die holder  41  to house the lower die  42 , a return coil  412  is provided at the bottom inside the accommodation hole  411 . Multiple screw eyes  414  extending into the accommodation hole  411  are provided by the die holder  41 , and the circumference of the lower die  42  has the same shape of the accommodation hole  411 , and a shear chute  421  is provided in the center of the lower die  42 . Multiple convex shear arc areas  422  in various radii extending inwardly are provided on the circumference of shear chute. Said guide post  43  having the same shape of that for the shear chute  421  is provided on its circumference multiple dents  431  corresponding to those convex shear arc areas  422 . Multiple screw eyes  432  and positioning pin holes  433  are provided on top of the guide post with matching fisheyes  442  and positioning pin holes  443  longitudinally penetrating through the upper die  44 . Multiple concave shear arc areas  441  are provided on the circumference of the upper die  44  to relatively connect to said convex shear arc areas  422 . 
     Upon assembling, a positioning pin  46  penetrates the positioning pin hole  443  and inserted into the positioning pin hole  433  while a upper die positioning bolt  45  penetrates the fisheye  442  and is secured in position in the screw eye  432  thus to incorporate the upper die  44  to the guide post  43 , which in turn is placed inside the shear chute  421  in the lower die  42 . Then the lower die  42  is placed inside the lower die accommodation hole  411  in the die holder  41 , and secured in position by having a lower die positioning bolt  413  deposed in a screw hole  414  to hold against the lower die. Meanwhile, the base of the guide post is subject to the holding by the return coil  412 , creating a gap reserved between the upper die  44  and the lower die  42  for being subject to the holding by the guide post  43 . Since the top of the upper die  44  is also restricted by the plunger  24 , the punch shear dies unit  4  is incorporated to the middle section of the primary support  2 . Furthermore, by having multiple fixing bolts  13  to penetrate those screw eyes provided in the peripheral of the main frame  1  and secured in those screw eyes  113  in the housing  11 , the housing  11  is incorporated to the main frame  1  and covers the main frame  1  on the press plate  25  and the driver  3 . The control pull  331  controlling the air control valve  33  protrudes out of a pre-perforated area  112  on top of the housing  11  and extends to where below the handle  111 . 
     In practical use, one end of a work piece of a plate pending punch shear is inserted into the dent  431  of the guide post  43  through the gap reserved between the upper die  44  and the lower die  42 . Press the pull  331  to control the air control valve  33  to activate the driver  3 , thus to push the press plate  25  on one end while the other end of the press plate  25  pressed down the plunger  24  for it to push against and causes the upper die to slide downward, and finally to shear the corner of a workpiece into a circular arc by means of those concave arc areas  441  from the upper die  44  in conjunction with those convex arc areas  422  from the lower die  42 . Upon completing the shear, the control pull  331  is released to retract the driver  3  controlled by the air control valve, then the return coil  412  holds against the guide post  43  and the upper die  44  for the press plate  25  to return to its initial position. 
     In the preferred embodiment of the present invention as disclosed above, said air connectors  31 ,  32  are provided by said main frame  1  for easy mounting or dismounting the inherited air pipe for connecting an external control valve so to fix the main frame  1  on a holder to become a fixed type of tooling machine.