Abstract:
A portable cam and lever actuated press which utilizes the substantial force available from an air spring to actuate one or more lever arms. The substantial force available from an air spring and the specialty cam system provided allows the device to perform clinching, crimping, punching, stenciling, riveting, stamping, holding, or other operations which would normally be performed with much larger and heavier equipment when the proper punches and dies are installed onto the lever arms. The unit operates pneumatically without the need for hydraulics or hydraulically assisted components.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates in general to punching, crimping and clinching equipment, and more particularly, to a portable punching, crimping and clinching press which is lever actuated and capable of accepting dies and punches capable of clinching or toggle locking sheet metal and which is preferably pneumatically activated. The present invention represents a unique lightweight press system which performs punching, crimping and clinching of sheet metal or other materials when used with the proper punches and dies. 
     Clinching is the process of bonding sheet metal materials together with the use of special punches and dies which are manufactured by various manufacturers. The term toggle locking is generically used in the industry and more particularly refers to the use of industry standard Tog-L-Loc® punches and dies of the BTM Corporation of Marysville, Mich. During the clinching process, the punches and dies form an indented portion into overlapping sheet metal material which bulges at the base of the indent in order to bond the materials. No claim is made to the actual clinching or toggle locking punches and dies in this application. A typical system of punches and dies which may be used with the present invention may be found in U.S. Pat. No. 4,459,735 assigned to BTM Corporation. The system of the present art is directed to a press system which holds and actuates said clinching punches and dies and may also serve hole punching, crimping, and stenciling functions when used with alternate punch and die sets. 
     The art of the present invention allows for the use of any combination of punches and dies which provide for various functions such as hole punching, crimping, stenciling, etc. A unique aspect of this device is the lightweight and portable press system which is capable of using compressed air for operation. The invention utilizes an air stroke actuator which is capable of providing large forces in a small volume and is also capable of flexing in its plain of movement. This flexible plain of movement allows a cam or cam follower on the actuator to follow a cam on a first or second lever arm. 
     With conventional clinching and punching press systems, ram movement is typically actuated by a hydraulic piston which is either pneumatically pressurized or pressured via a hydraulic pump. This form of actuation typically creates a press which has a bulk and weight which prohibits the press from handheld and portable operation. It further adds to the cost of the press. The few clinching and punching press systems which are strictly pneumatic are of such size and weight that hand held portable operation is not possible. The preferred embodiment of the present art utilizes the substantial force provided by an air stroke actuator to actuate a lever arm which performs clinching, crimping, punching, or other operations. 
     Accordingly, it is an object of the present invention to provide an improved lever actuated clinching, crimping, and punching press which provides sufficient force for clinching, crimping, punching, and other operations and which is also portable and capable of handheld use. 
     Another object of the present invention is to provide an improved lever actuated clinching, crimping, and punching press which is capable of pneumatic operation with conventional compressed air and without hydraulic cylinders or hydraulic pumping equipment. 
     A further object of the present invention is to provide an improved lever actuated clinching, crimping, and punching press which is capable of using various punches and dies to perform various operations on sheet metal or other materials. 
     A still further object of the present invention is to provide an improved lever actuated clinching, crimping, and punching press which is manufactured from a minimum number of components and which is cost effective. 
     SUMMARY OF THE INVENTION 
     To accomplish the foregoing and other objects of this invention there is provided an improved lever actuated clinching, crimping and punching press for use in clinching, crimping, punching, piercing, and stenciling operations and also for holding materials. The system comprises a frame into which is mounted an air stroke actuator, typically a pneumatically operated air spring, having a cam or cam follower attached to a single end, a first lever arm having a first cam roller, a second lever arm having a second cam roller, in addition to the special punches and dies. Alternative embodiments may incorporate the second lever arm as the frame. 
     In the preferred embodiment, said frame comprises a preferably metallic frame with an opening for mounting said air stroke actuator near a first end and associated cam or cam follower components with said actuator. Preferably a pivot shaft is pivotably mounted through said frame and first and second lever arms. Onto the second ends of the lever arms is mounted the punches or dies. Also, each punch is preferably adjustably mounted within a hole in the second end of each lever arm. This allows for adjustment of the punch extension. In the preferred embodiments, opposite said punch is mounted a die onto the opposing lever arm second end. Each of the cam rollers have a housing which holds each cam roller at the first end. Each of said housings may be integral with one or more of the lever arms. Alternative embodiments may forego use of the cam or cam follower and place air stroke actuator directly between the lever arms. 
     For clinching operations, the punch typically comprises a ram bushing and stripper which are mounted with and onto an end of said punch. The stripper is typically comprised of a flexible yet durable hollow tube which is able to compress during punch use. The ram bushing has a through-hole through which the punch may protrude and is mounted within said stripper. This arrangement allows the sheet metal to be held between the ram and die by said bushing before the punch performs the clinching operation. The punch, stripper, ram bushing, and die components are uniquely adapted to the clinching, punching, crimping or stenciling operation function and are proprietary to the manufacturer of said components. No claim is made to said components apart from their operation and use with the press of the present invention. 
     In operation, the user installs the desired punch and die combination and places the piece or pieces of sheet metal or other material between said punch and die. Upon application of compressed air to the air stroke actuator, the cam or cam follower of said air stroke actuator is driven forward between the first and second cam rollers which are mounted with the first ends of the first and second lever arms respectively. The force placed upon and between said cam rollers by the cam or cam follower of the actuator causes the second ends of the lever arms to be forced together. The aforesaid movement of the lever arms causes the aforementioned punch and die to contact and compress the piece or pieces of sheet metal between said punch and die. The extension of the punch into the die is limited by the size of the cam or cam follower attached with said actuator, moment arm length between the lever arm first end and second end relative to the pivot shaft, and the punch adjustment within the mounting hole. The lever arms preferably return to an open rest position when the air pressure to the air stroke actuator is released via the action of the return spring. Preferably the pneumatic pressure is controlled via a pneumatic valve which pressurizes the air stroke actuator when pressed and then vents the actuator when released. 
     This press and its associated components may be manufactured of many types of materials including but not limited to plastic, composites, and various metals and their alloys as required by the application. In a preferred embodiment, the frame and housings are manufactured from an aluminum alloy, and the ram, rollers, and bolts from steel. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Numerous other objects, features and advantages of the invention should now become apparent upon a reading of the following detailed description taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a perspective view of a first embodiment of an improved portable cam and lever actuated clinching, crimping, and punching press with the lever arms in an open position and the air stroke actuator un-pressurized and a guard or cover over the actuator and cam rollers. 
     FIG. 2 is a right side plan view of a first embodiment of an improved portable cam and lever actuated clinching, crimping, and punching press with the lever arms in an open position and the air stroke actuator un-pressurized. The right side plan view is substantially symmetric with the left side plan view. 
     FIG. 3 is a right side plan view of a second embodiment of an improved portable cam and lever actuated clinching, crimping, and punching press with the lever arms in an open position and the air stroke actuator un-pressurized. The right side plan view is substantially symmetric with the left side plan view. 
     FIG. 4 is a cross sectional view of the first embodiment taken along the central axis of the press and cut line  4 - 4 A of FIG.  2 . 
     FIG. 5 is a cross sectional view of the second embodiment taken along the central axis of the press and cut line  5 - 5 A of FIG.  3 . 
     FIG. 6 is a right side plan view of an alternative embodiment of an improved portable cam and lever actuated clinching, crimping, and punching press with the lever arms in an open position and the air stroke actuator un-pressurized. The right side plan view is substantially symmetric with the left side plan view. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings, there is shown in FIGS. 1,  2 , &amp;  4  a preferred embodiment and in FIGS. 3 &amp; 5 an alternative embodiment of the improved portable cam and lever actuated clinching, crimping, and punching press  10  of the present invention. Subject to the types of punches and dies used, the improved portable cam and lever actuated clinching, crimping, and punching press  10  is particularly adapted for use in clinching, crimping, punching, stenciling, riveting, stamping, piercing, and holding operations of sheet metal or other materials. A unique feature of the present invention is its utilization of the substantial force provided by an air stroke actuator  12  in the form of an air spring in conjunction with the special cam and lever system to provide the required force for the aforementioned operations. All component attachments, when necessary, are achieved with conventional fasteners such as screws, bolts, threads, pins, welds, adhesives or rivets as desired by the manufacturer of the art described. 
     The drawings show the improved portable cam and lever actuated clinching, crimping, and punching press  10  comprising a frame  16  having an opening  40 , a first lever arm  14 , a second lever arm  19 , a pivot shaft  39 , a pneumatic valve  42 , and a return spring  30  in a preferred embodiment. Onto said frame  16  and into said opening  40  of said frame  16  is mounted a first end  11  of an air stroke actuator  12 , typically an air spring from companies such as Goodyear® or Firestone®. The preferred embodiment further comprises a hand grip  44  with which is mounted a pneumatic valve  42 . 
     As shown in the preferred embodiment, said second lever arm  19  may be utilized as said frame  16  in some embodiments and have limited or no movement. Also, the frame  16  and second lever arm  19  may be integrally mounted together. In further embodiments, the frame  16  may be held in position with the first and second lever arm  14 ,  19  via the pivot shaft  39  without departing from the scope of the present invention. Also, the displacement direction of the actuator  12  may be reversed in alternative embodiments without departing from the scope of the present invention. 
     An air spring is a commercial component which typically comprises a rubber bag having an air inlet and mounting plates on each end for attachment. When pressurized, each end displaces relative to the other. Since force is proportional to air pressure multiplied by cross sectional area, the air spring provides significantly more force than a typical air cylinder arrangement due to the substantial cross sectional area of the rubber bag. A further advantage of the air spring is its ability to flex within its plane of movement thereby allowing for misalignments of connected components which mate with other components. In alternative embodiments where lesser punching, crimping, or clinching forces are required, the air stroke actuator  12  may take the form of an air piston and cylinder. Generally said air stroke actuator  12  extension movement is substantially perpendicular to the movement of a first end  15  of the first lever arm  14  and a first end  26  of the second lever arm  19 . Alternative embodiments may place said actuator  12  directly between said first end  15  of the first lever arm  14  and the first end  26  of the second lever arm  19 . Pressurized air is provided to the actuator  12  via a feed hose from a pneumatic valve  42 . A compressed air supply feeds said pneumatic valve  42 . 
     In the preferred embodiment, onto a second end  21  of said air stroke actuator  12  is mounted a cam follower or rolling cam housing  31  which houses an extending cam follower or rolling cam  29 . Alternative embodiments may simply utilize a cam  35  with a user desirable profile attached with said second end  21  without departing from the scope of the present art. Within the art, said cam follower or rolling cam  29  may also be referred to as a cam. Said cam follower or rolling cam  29  or cam  35  is positioned within said opening  40  near or between a first cam roller  18  and a second cam roller  22 . Each of said rollers or followers  29 ,  18 ,  22  is able to rotate within its respective housing  31 ,  20 ,  24 . Said first cam roller  18  is mounted within its first cam roller housing  20  and said housing  20  is attached to the first end  15  of said first lever arm  14 , substantially opposite the second lever arm  19  and the second cam roller  22 . If a cam follower  29  is utilized, an actuator stop  23  is typically placed onto and extends from the second end  21  of said actuator  12 . This stop  23  prevents the centerline of the cam follower  29  from extending beyond the center line of the cam rollers  18 ,  22  and thereby binding the device in a closed position. If a cam  35  is utilized instead of a cam follower  31 , the profile of the cam  35  is chosen to minimize the possibility of device binding in a closed position. 
     Said second cam roller  22  is mounted within the second cam roller housing  24  and said housing  24  is mounted onto or near a first end  26  of said second lever arm  19 . Alternative embodiments may forego use of the first and second cam rollers  18 ,  22 , provided the alternative bearing surfaces allow the cam follower  29  or the cam  35  to separate and impart force to the first and second lever arms  14 ,  19 . Within the art, said cam rollers  18 ,  22  may also be referred to as bearing surfaces. 
     In a preferred embodiment, a return spring  30  is engaged with or mounted between said first lever arm  14  and said second lever arm  19 . The preferred embodiment utilizes a spring arm  41  on said first lever arm  14  which compressively sandwiches the return spring  30  between said arm  41  and said second lever arm  19  or frame  16 . As aforesaid, the second lever arm  19  may function as the frame  16  and provide mounting for the air stroke actuator  12  in some embodiments. The return spring  30  provides for second end  28 ,  17  lever arm  14 ,  19  opening when the air pressure is released from the air stroke actuator  12 . Alternative embodiments may place said return spring  30  at a plurality of locations to achieve the aforementioned benefits. Alternative embodiments may also utilize springs in tension, or utilize torsion or leaf springs to achieve the aforementioned benefits. 
     In a preferred embodiment, onto said second lever arm  19  near a second end  28  is placed the desired punch  34  and opposite said punch on said first lever arm  14  near a second end  17  is placed the desired die  38 . Should the operation require, the die  38  and punch  34  may be switched opposite in placement. Should the user desire to perform a clinching operation, a stripper  32  and a ram bushing  36  would be provided around said punch  34 . The present art utilizes punches  34  and dies  38  which are provided by third parties and does not claim the art of said punches  34  and dies  38 . Nevertheless, those skilled in the art will recognize that various modifications to the lever arms  19 ,  14  may be required in order to use the desired punch and die combination. This may require drilling, threading and other machining operations to the lever arms  19 ,  14 . 
     In the preferred embodiment, the first lever arm  14  pivotably connects with the second lever arm  19  via a pivot shaft  19 . In the preferred embodiment said shaft  19  is simply a pin placed through holes in said lever arms  14 ,  19 . Alternative embodiments may utilize bolts, screws, tubes, rivets, dowels, or other pivotal connecting devices in place of said pivot shaft  19 . Also in a preferred embodiment, said first lever arm  14  fits within a cavity or channel within said second lever arm  19 . Alternative embodiments may pivotably attach and fit the two arms  14 ,  19  in a plurality of ways, including but not limited to extension arms, plates, cavities, or hinges which allow the two arms  14 ,  19  to pivot in alignment. 
     The size of said cam follower or rolling cam  29  or cam  35  of said air stroke actuator  12  controls the relative displacement of said first ends  15 ,  26  of the lever arms  14 ,  19 . Since the lever arms  14 ,  19  are pivotably connected with the pivot shaft  39 , the force placed upon said rollers  18 ,  22  by the cam follower or rolling cam  29  or cam  35  driving between said rollers  18 ,  22  causes the second ends  17 ,  28  to be forced toward each other. This causes the aforementioned punch  34  to contact and compress the piece or pieces of sheet metal between said punch  34  and die  38 . The relative movement of the punch  34  and die  38  are controlled by the relative moment arms between the punch  34 , die  38 , first cam roller  18 , second cam roller  22  and the pivot shaft  39 . That is, if L 11  is the moment distance from the first cam roller  18  axis to the pivot shaft  39  axis, and L 12  is the moment distance from the die  38  central axis to the pivot shaft  39  axis, and L 21  is the moment distance from the second cam roller  22  axis to the pivot shaft  39  axis, and L 22  is the moment distance from the punch  34  central axis to the pivot shaft  39  axis, and the cam follower  29  or cam  35  displaces the first ends  15 ,  26 , by an amount d 1 , the displacement or movement of the punch  34  and die  38 , d 2 , is defined as: 
     
       
         
           d 
           2 
           =d 
           1 
           *L 
           12 
           /L 
           11 
         
       
     
     provided that L 11  and L 21  are substantially equal and L 12  and L 22  are substantially equal. Likewise, the force at and between the second end may be related to the force at and between the first end as: 
     
       
         
           F 
           2 
           =F 
           1 
           *L 
           11 
           /L 
           12 
         
       
     
     Thus, the first and second lever arms  14 ,  19  are able to provide a force or displacement multiplier for the substantial force available from the actuator  12 . Since L 12  is generally shorter than L 11  in the preferred embodiment, the present invention provides a force multiplication of that portion of the actuator  12  force which the cam follower  31  or cam  35  places upon the first ends  15 ,  26 . The position of the punch  34  relative to the die  38  upon full pressurization and displacement of the actuator  12  is further controlled by the length of extension of said punch  34  or possibly said die  38  from said second end  17 ,  28 . 
     In the preferred embodiment when utilizing a cam  35 , the cam  35  has a short first section with a steep or accelerated profile to move the die  38  and punch  34  at the second ends  17 ,  28  near or onto the sheet metal. This short profile limits the force transfer from the actuator  12  to the lever arms  14 ,  19 . The cam  35  thereafter has an elongated second section with a gradual or lower profile which provides less second end  17 ,  28  displacement but more force to perform the clinching, crimping, punching or other operations. Alternative embodiments may utilize cams  35  with a plurality of profiles without departing from the scope and spirit of the present invention. 
     The alternative embodiment which does not utilize a cam  35 , cam follower  29 , or cam rollers  18 ,  22  simply attaches the air stroke actuator  12  first end  11  with or near the first end  15  of the first lever arm  14  and the air stroke actuator  12  second end  21  with or near the first end  26  of the second ever arm  19 . That is, as the air stroke actuator  12  attaches with the frame  16  or second lever arm  19  in a preferred embodiment, it may attach with the first end  15  of the first lever arm  14  in an alternative embodiment. Also, as the air stroke actuator  12  attaches with the cam  35  or cam follower  29  in a preferred embodiment, it may also attach with the first end  26  of the second lever arm  19 . Although, not providing the force or positioning control advantages of the cam system, the aforesaid alternative embodiment does provide the clinching, crimping, punching, and other operations of the present art. 
     In operation, the user installs the desired punch  34  and die  38  combination as aforesaid and places a piece or pieces of sheet metal between said punch  34  and die  38 . The user then activates a pneumatic valve  42  to pressurize the actuator  12 . Upon application of compressed air to the air stroke actuator  12 , the cam follower or rolling cam  29  or cam  35  of said air stroke actuator  12  is driven forward between said first cam roller  18  and said second cam roller  22 . Upon pressurization, the punch  34  and die  38  approach and contact the surfaces of the sheet metal to perform the operation. Upon deactivation of the valve  42 , the actuator  12  is vented to atmosphere and depressurized. Upon depressurization of the actuator  12 , the return spring  30  returns the lever arms  14 ,  19  to the original opened and rested position, whereby the material there between may be removed. 
     As described, the art of the present invention is shown with a clinching die  38  and its associated punch  34 , stripper  32 , and ram bushing  36  in place. The clinching process bonds two pieces of sheet metal together by forcing a portion of the sheet metal defined by the diameter of the punch  34  into a die  38  having an inverted taper. The die  38  expands outwardly when the punch  34  retracts, thereby allowing for removal of the sheet metal. The art of the present invention is drawn to the press  10  alone and the combination of the press  10  with the clinching, crimping, punching, stenciling, or holding punches and dies of the user&#39;s choice but no claim is made to the punches and dies apart from the press. 
     From the foregoing description, those skilled in the art will appreciate that all objects of the present invention are realized. An improved press for clinching, crimping, punching, stenciling, riveting, stamping, and holding operations is shown which is particularly adapted for operation with sheet metal. The press of this invention is able to provide the required force for such operations without the use of hydraulics or exceptionally large and heavy equipment. 
     Having described the invention in detail, those skilled in the art will appreciate that modifications may be made to the invention without departing from its spirit. Therefore, it is not intended that the scope of the invention be limited to the specific embodiments illustrated and described. Rather it is intended that the scope of this invention be determined by the appended claims and their equivalents.