Patent Publication Number: US-10786844-B2

Title: Balanced panel punch drive system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of priority of U.S. provisional application No. 62/353,363, filed Jun. 22, 2016, the contents of which are herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a hydraulic punch drive system and, more particularly, to a balanced hydraulic punch drive system. 
     In hydraulic presses slides are provided which reciprocate toward and away from the press bed on which there is a die and a work piece to be stamped. The press is provided with a main hydraulic system which provides closing cylinders at each end of the press with hydraulic fluid under pressure for moving the slide toward the bed. Pull-back cylinders are also provided to which hydraulic fluid under pressure is fed for the purpose-of moving the slide away from the bed after the drawing operation has been performed. 
     In hydraulic presses particularly, and especially the larger ones, there is always a tendency for one end or the other of the slide to move faster or slower than the other end especially during the working stroke. Furthermore, if this is permitted to occur, there is a possibility that one part of the slide may press against a work piece when another part does not. There will, therefore, be a tendency for that part of the slide which is out of contact with the work piece to continue to move, whereupon the slide becomes out of alignment and exerts undue pressures against the sides of the press frame. The present invention is designed to overcome these difficulties and to synchronize the movements of the ends of the slide so that they will be maintained at constant relative levels throughout the entire stroke of the slide. 
     As can be seen, there is a need for a hydraulic metal working press, suitable mechanism for synchronizing the reciprocating movement of a slide therein and maintaining both ends of the slide at constant relative levels throughout the entire stroke thereof. 
     SUMMARY OF THE INVENTION 
     In one aspect of the present invention, a balanced panel punch drive system comprises: a main hydraulic drive comprising an outer casing forming an internal housing and a main piston slidably disposed along a longitudinal axis within the internal housing, wherein a main fluid chamber, a first output chamber and a second output chamber are formed within the internal housing; a pump; an input line fluidly connecting the pump to the main fluid chamber; a first die hydraulic cylinder and a second die hydraulic cylinder each comprising an outer casing forming an internal housing and a die piston slidably disposed along a longitudinal axis within the internal housing, wherein an opening is formed through an end of the outer casing sized to receive a distal end of the die piston therethrough; a first output line fluidly connecting the first output chamber to a main die chamber of the internal housing of the first die hydraulic cylinder; and a second output line fluidly connecting the second output chamber to a main die chamber of the internal housing of the second die hydraulic cylinder. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an embodiment of the present invention; 
         FIG. 2  is a reverse perspective view of an embodiment of the present invention; 
         FIG. 3  is a perspective detail view of an embodiment of the present invention illustrating valves in an initial position; 
         FIG. 4  is a perspective detail view of an embodiment of the present invention illustrating valves in a secondary position; 
         FIG. 5  is an exploded detail view of an embodiment of the present invention; 
         FIG. 6  is a reverse exploded detail view of an embodiment of the present invention; 
         FIG. 7  is a cutaway detail perspective view taken along line  7 - 7  in  FIG. 2 ; 
         FIG. 8  is a section detail top view of the present invention taken along line  8 - 8  in  FIG. 1 ; 
         FIG. 9  is a section detail cutaway view of the present invention taken along line  9 - 9  in  FIG. 2  in an initial configuration; 
         FIG. 10  is a section detail cutaway view of the present invention in a secondary configuration; 
         FIG. 11  is a cutaway detail perspective view of an embodiment of the present invention in use; 
         FIG. 12  is a section detail top view of an embodiment of the present invention illustrating dual resultant shear action; 
         FIG. 13  is an exploded detail view of an embodiment of the present invention; and 
         FIG. 14  is a schematic view of an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims. 
     Referring to  FIGS. 1 through 14 , the present invention includes a balanced panel punch drive system. The system includes a main hydraulic drive  14  including an outer casing  24  forming an internal housing and a main piston  28  slidably disposed along a longitudinal axis within the internal housing. A main fluid chamber  18 , a first output chamber  20  and a second output chamber  22  are formed within the internal housing. A pump  10  is fluidly connected to the main fluid chamber  18  by an input line  12 . The system further includes a first die hydraulic cylinder  42  and a second die hydraulic cylinder  44  each having an outer casing  46  forming an internal housing and a die piston  48  slidably disposed along a longitudinal axis within the internal housing. An opening is formed through an end of the outer casing  46  sized to receive a distal end of the die piston  48  therethrough. A first output line  30  fluidly connects the first output chamber  20  to a main die chamber  50  of the internal housing of the first die hydraulic cylinder  42  and a second output line  32  fluidly connects the second output chamber  22  to a main die chamber  50  of the internal housing of the second die hydraulic cylinder  44 . 
     The pump  10  of the present invention may be a hydraulic pump. The hydraulic pump may include a manual pump that is hand cranked or an automatic pump that is driven by a motor. 
     The internal housing of the main hydraulic drive  14  includes a wide portion and a narrow portion. The main piston  28  also includes a wide portion and a narrow portion. The wide portion of the main piston  28  is slidably disposed within the wide portion of the internal housing and the narrow portion of the main piston  28  is slidably disposed within the narrow portion of the internal housing. The wide portion of the main piston  28  may be biased by a spring against the internal housing. The main fluid chamber  18  is formed within the wide portion of the internal housing between an end of the wide portion of the main piston  28  and an end of the internal housing. The first output chamber  20  is formed within the wide portion of the internal housing in between the wide portion of the main piston  28  and the narrow portion of the internal housing. The second output chamber  22  is formed within the narrow portion of the internal housing in between the narrow portion of the main piston  28  and an opposing end of the internal housing. The first output chamber  20  and the second output chamber  22  have an equal volume and thereby deliver an equal amount of fluid  26  to the first and second die hydraulic cylinders  42 ,  44 . 
     The internal housing of each of the first and second die hydraulic cylinders  42 ,  44  includes a wide portion and a narrow portion. Each of the die pistons  48  includes a wide portion and a narrow portion. The wide portions of the die pistons  48  is slidably disposed within the wide portions of the internal housings and the narrow portion of the die pistons  48  is slidably disposed within the narrow portions of the internal housings. The wide portions of the die pistons  48  may be spring biased against the internal housings. The main die chambers  50  of the first and second die hydraulic cylinders  42 ,  44  are formed between an end of the internal housing opposing the openings and the wide portions of the die pistons  48 . A secondary chamber  52  is formed in between the wide portions of the die pistons  48  and the openings. The wide portions of the die pistons  48  abut against the narrow portions of the internal housings when the die pistons  48  are extended from the openings. 
     The present invention may further include a first valve line  34  fluidly connecting at least one of the main fluid chamber  18  and the pump  10  to the main die chamber  50  of the first die hydraulic cylinder  42  and a second valve line  36  fluidly connecting at least one of the main fluid chamber  18  and the pump  10  to the main die chamber  50  of the second die hydraulic cylinder  44 . As illustrated in the Figures, the valve lines  34 ,  36  run from the main fluid chamber  18  to the output lines  30 ,  32 . A first valve  38  is operable to control a flow through the first valve line  34  and a second valve  40  is operable to control a flow through the second valve line  36 . 
     Each of the first die hydraulic cylinder  42  and the second die hydraulic cylinder  44  includes at least one threaded opening  68  formed at the end of the outer casing  46 . The at least one threaded opening  68  may include a plurality of threaded openings  68  equidistant to one another. The present invention may further utilize threaded bolts  66  sized to fit through aligned openings  58 ,  64  of a die set  54 ,  60  and mechanically fasten to the threaded openings  68 . The die set  54 ,  60  includes a die backing plate  54  and a die cutter plate  60 . The die backing plate  54  includes openings  58  and a die plate inset  56 . The die cutter plate  60  includes openings  64  and a cutting rim  62 . 
     In use, the threaded bolts  66  are placed through the openings of the die cutter plate  60 , through the openings  78  of a target plate  70 , through the openings of the die backing plate  54  and are mechanically fastened to the threaded openings  68  of the first and second die hydraulic cylinders  42 ,  44 . The first and second valves  38 ,  40  are opened, allowing fluid  26  to run into the main die chambers  50  pushing the die pistons  48  so that the die pistons  48  are evenly pressed against the die backing plate  54  at around 300 psi. The first and second valves  38 ,  40  are then closed. The pump  10  is then activated to pump the fluid  26  into the main fluid chamber  18  of the outer casing  24  at a higher pressure of around 1000 psi, pushing the main piston  28  forward causing the main piston  28  to push an equal amount of fluid  26  from the first output chamber  20  into the main die chamber  50  of the first die hydraulic cylinder  42  and from the second output chamber  22  into the main die chamber  50  of the second die hydraulic  42 , thereby pushing the die pistons  48  of the first and second die hydraulic cylinders  42 ,  44  against the die backing plate  54  at an even pressure. Due to the increased pressure, the cutting rim  62  cuts out a cut plate shear shape  74  and a shear plate  76  from the target plate  70 . 
     It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.