Abstract:
The present invention relates to a general purpose clamping device which is called the inserta clamp. It comprises a straight shank with the lower end attached to a short cylindrical sleeve and a movable arm sliding over the shank. Feeding through the free end of the movable arm is a threaded rod with clamping pad and turning handle at the lower end and upper end respectively. The present invention is designed to hold a workpiece tightly, quickly and conveniently on the working surface of a table, workbench or machine tool. And the invention can be relocated easily over the workbench made of wood or metal, or over the working surface of a machine tool. Attachments are provided to enhance the functionality of the invention.

Description:
REFERENCE  
       [0001]    
       
         
               
             
               
               
               
               
             
           
               
                   
               
               
                   
               
               
                 U.S. PATENT DOCUMENTS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 2,764,195 
                 Sep. 25, 1956 
                 William Heimes 
               
               
                   
                 2,877,815 
                 Mar. 17, 1959 
                 William A. Fonken 
               
               
                   
                 3,623,718 
                 Nov. 30, 1971 
                 Eugene J. Thomeczek, Sr. 
               
               
                   
                   
               
             
          
         
       
     
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a general purpose clamping device and more particularly to an inserta clamp. The invention is designed to hold a workpiece tightly, quickly and conveniently on the working surface of a table, a workbench, or a machine tool. Yet the invention can be relocated easily for different configuration and can be removed without trouble after work. The working surface of the table or workbench can be made of wood or metal, whereas the working surface of a machine tool is a metal surface with or without tooling holes.  
         [0004]     The present invention comprises a straight shank with the lower end attached to a short cylindrical sleeve and a movable arm sliding over the shank. Feeding through the free end of the movable arm is a threaded rod with clamping pad at the lower end and turning handle at the upper end. Attachments of various designs, including a cylindrical mounting base, Y-axis attachment are provided to enhance the functionality and flexibility of the present invention. A quick release button is equipped at the upper end of the straight shank to enable the easy insertion and easy removal of the movable arm or the Y-axis attachment to or from the shank. The clamping pad is designed so that it can be rotated freely and swiveled through a limiting angle.  
         [0005]     To clamp a workpiece on the working surface of a machine tool with tooling holes, the present invention is inserted with the short cylindrical sleeve into one of the tooling holes on the working surface. For those working surfaces without tooling holes, the present invention is inserted to the cylindrical mounting base which is mounted on the working surface with screws. Same method can be used for wooden workbench too. For application on other metal working surfaces, a short cylindrical metal tube with the right diameter can be spot welded on the working surface for the insertion of the cylindrical sleeve at the lower end of the straight shank. When inserted onto the shank of the present invention, the Y-axis attachment can be used for two-dimensional (X and Y axes) clamping of two or more workpieces simultaneously. With these attachments, the functionality and flexibility of the present invention is greatly enhanced.  
         [0006]     2. Description of the Related Art  
         [0007]     In the field of bonding, welding and machining, clamps are used for holding workpieces together or holding workpiece on a workbench. Various types of clamps are available, such as bar clamps, C-clamps, F-clamps and screw clamps. These clamps generally comprise a fixed arm with fixed clamping pad and a movable arm with clamping pad, or a fixed arm with fixed clamping pad at one end and a movable clamping pad attached directly to the other end of the fixed arm. Bar clamp utilizes a sliding arm over the fixed arm to clamp a workpiece. Different types of quick locking and quick releasing mechanism for the sliding arm are available in the field. C-clamp consists of a C-shape fixed arm with clamping pad at one end and a threaded rod with clamping pad and cranking handle at the other end. The movable arm of a F-clamp is a straight arm with one end sliding over the L-shape fixed arm and the other end feeding a threaded rod with clamping pad. Screw clamp utilizes two parallel clamping arms opened and closed by two parallel screws. To clamp a workpiece to the surface of a workbench, these conventional clamps must be used at the edge of the workbench so that one of the clamping arms will cross over the edge and reach the bottom of the working surface of the bench. For small workpiece on small workbench, this characteristic does not affect the effectiveness of these clamps. However, when the workpiece and the workbench are relatively large, the middle part of the workpiece will be out of the reach of the clamping arms and clamping pads. To overcome this problem, one has to make use of clamping bars, beams or any suitable fixture to hold these conventional clamps over the middle part of the workpiece and hence clamping pressure can be applied on the workpiece. This is a logical way to solve the problem, but it is also a very time consuming and inconvenient way to get the job done. Better ways of solving this problem had been devised in the past. For example, U.S. Pat. No. 2,764,195 Adjustably Mounted Bench Clamp by W. Heimes, utilizes a L-shape clamp beam inserting into a circular face plate and a sleeve. The face plate and the sleeve are mounted by screws through a cylindrical hole on the work bench so that the upper surface of the face plate is flush with the bench top. The protrusion of the L-shape clamp beam above the bench top is controlled and locked by a spring-loaded plunger and hand knob mounted to the sleeve under the workbench. According to the design of this prior art, user has to mount the face plate and the sleeve to both the top and the bottom surfaces of a pre-drilled hole on the workbench. To adjust the clamping gap or to remove the L-shape clamp beam, the user has to go underneath the workbench to disengage the plunger with the hand knob. When the workpiece and the workbench are relatively large, it would be very inconvenient to do so. Another example, U.S. Pat. No. 2,877,815 Canting Holddown Clamp by W. A. Fonken, has similar but simpler design as the above-mentioned Bench Clamp. It has the inconvenience of mounting the bushings to the bottom surface of the workbench but the convenience of adjusting the clamping gap or to relocate the L-shape shank simply from the top of the workbench. Yet another example, U.S. Pat. No. 3,623,718 Clamp Assembly by Eugene J. Thomeczek, Sr., comprises an elongated rack with horizontal slots for the detent of a clamping bar at a desired distance from the bench top. A clamping bolt is fed through the elongated slot of the clamping bar and screw into the threaded hole on the workbench or through a hole on the bench into the nut underneath to clamp the workpiece. This clamp is very simple in design and easier to use and relocate on a bench top. The only inconvenience is to prepare threaded holes or holes with nuts underneath the bench top for the clamping bolt.  
       BRIEF SUMMARY OF THE INVENTION  
       [0008]     It is the intention of the present invention to provide a clamping device to hold a workpiece tightly, quickly and conveniently anywhere on the working surface of a table, a workbench, or a machine tool regardless of the size of the workpiece and the working surface. Another intention is to enable the present invention to clamp workpiece anywhere on the working surface without the use of clamping bars, beams or fixtures. Yet another intention of the present invention is to enable the clamping of a workpiece against the working surface without crossing over the edge and reaching the bottom of the work table, workbench or machine tool. It is also the intention of the present invention to lock itself on the working surface by means which can be applied and removed on the top surface only, there is no need to work underneath the work table, workbench or machine tool. Another intention of the present invention is to make a clamping device which can be used on various types of working surface, such as wood, metal or machine tool, and yet it can be relocated easily over the surface. Further intention of the present invention is to expand the functionality and flexibility of a clamping device by adding the quick release button to the shank, the cylindrical mounting base and the Y-axis attachment.  
         [0009]     The present invention comprises a straight shank with the lower end attached to a short cylindrical sleeve and a movable arm sliding over the shank. Feeding through the free end of the movable arm is a threaded rod with clamping pad at the lower end and turning handle at the upper end. The clamping pad is designed so that it is free to rotate omni-directionally and free to swivel at certain angle to meet perfectly with the uneven surface of the workpiece. The turning handle is used to turn the threaded rod downward or upward through the movable arm to clamp or release the workpiece.  
         [0010]     To clamp a workpiece on a working surface, the straight shank with the short cylindrical sleeve is attached to the surface and then the movable arm is moved up or down along the shank to a proper location so that the threaded rod can be lowered to clamp the workpiece with the clamping pad. For machine tool application, the short cylindrical sleeve at the bottom of the shank is inserted into one of the tooling holes on the working surface of the machine tool. If the size of the tooling hole is too big for the cylindrical sleeve, sleeve of the right size will be used between the shank and the hole. When pressure is applied to the workpiece through the movable arm and the clamping pad, the shank is tilted a little bit so that the short cylindrical sleeve is skewed against the wall of the tooling hole and the friction created will be sufficient to hold the workpiece against the working surface. For those working surfaces without tooling holes, the short cylindrical sleeve of the straight shank is inserted to the cylindrical mounting base which is mounted on the working surface with screws. The same method can be used on wooden work table or workbench too. To use the present invention on metal surfaces other than the machine tool, the cylindrical mounting base can also be used as described above. Besides that, a short cylindrical metal tube with an internal diameter a little bit bigger than the external diameter of the short cylindrical sleeve of the shank is spot welded on the metal surface where clamping is required. Then the short cylindrical sleeve of the shank is inserted into the short cylindrical tube and the workpiece can be clamped as mentioned above. To relocate or remove the present invention after work, the clamping pad is released from the workpiece and hence the friction between the short cylindrical sleeve and the short cylindrical tube is reduced too. Then the present invention can be removed from the working surface. The short cylindrical tube can easily be removed by breaking the spot weld with a hammer striking it or prying it with a metal rod, and then the metal surface can be polished to remove the spot weld residue with a suitable power hand tool.  
         [0011]     A Y-axis attachment is devised to enhance the functionality and flexibility of the present invention. It comprises two rectangular metal plates with an elongated hole in the middle and spaced apart by cylindrical blocks at each end, a rectangular block fits inside but free to move between the two metal plates. Two threaded rods fed through each one of the cylindrical blocks respectively. The rectangular block is equipped with a rectangular hole in the middle. The size of the hole is a bit bigger than the cross-section of the straight shank so that the shank can be fed through it freely. Screw hole is provided on one side of the rectangular block to accept screw to secure the position of the rectangular block to the shank so that the Y-axis attachment will not move or drop along the shank. The shorter one of the threaded-rods is attached to a clamping pad while the longer one is equipped with a turning handle. The longer threaded rod is left-hand threaded and the free end of it is pivoted to the rectangular block. Hence turning the longer threaded rod clockwise with the turning handle will advance the Y-axis attachment towards the clamping pad end or the workpiece and turning it counterclockwise will retract the assembly away from the workpiece. With the Y-axis attachment slid over the shank of the present invention, it is possible to clamp a second workpiece along an axis perpendicular to the clamping direction of the first workpiece.  
         [0012]     To facilitate the easy insertion and removal of the Y-axis attachment and the movable arm from the straight shank, a quick release button is equipped at the upper end of the shank. It is a metal push button with a loaded compression spring inside. Normally, it prevents the movable arm and the Y-axis attachment from dropping off the shank and when it is pressed, the insertion and removal of these items will be very easy.  
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0013]      FIG. 1  is a perspective view of the present invention with the Y-axis attachment.  
         [0014]      FIG. 2  is a perspective view of the present invention inserted into a tooling hole of the working surface of a machine tool (partly shown).  
         [0015]      FIG. 3  is a perspective view of the present invention with the cylindrical base unit.  
         [0016]      FIG. 4  is a perspective view of the present invention inserted into a short cylindrical tube spot welded on a metal working surface. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]     With the help of the drawings and the detail description below, the features of the present invention will be apparent and fully understandable.  
         [0018]     Referring to  FIG. 1 , the present invention, inserta clamp comprises a straight shank  1 , a short cylindrical sleeve  2  attached and fixed to the lower end of shank  1  by taper pin  3 , and a movable arm  4  with one end slid over the top end of shank  1  through rectangular hole  5  and the other end fitted with a threaded rod  6 , turning handle  7  and the clamping pad  8 . The straight shank  1  acts as the fixed arm of a conventional clamp. At the upper end of shank  1 , a spring loaded quick release button  9  is equipped to prevent the falling off of the movable arm  4  and other attachments from shank  1 , but at the same time it allows quick and easy insertion of these items onto shank  1 . Movable arm  4  is a metal bar with a rectangular hole  5  at one end  10  and a cylindrical threaded hole  11  at the other end  12 . The upper end of shank  1  is inserted into hole  5  of end  10  so that movable arm  4  is free to move upward and downward on the body of shank  1 . The size of hole  5  is just a bit bigger than the cross section of shank  1  so that the movable arm will not be too loose on the body of shank  1 . Threaded rod  6  is screwed into threaded hole  11  of end  12  of the movable arm  4 . Turning handle  7  is inserted into a hole at the upper end  13  of the threaded rod  6  and a clamping pad  8  is pivoted to the lower end of threaded rod  6 . Clamping pad  8  is free to rotate about the tip at the lower end of threaded rod  6  and to swivel through a limited angle in any directions. Upper end  13  of threaded rod  6  is made to be hexagonal with standard nut size so that a wrench may be used to turn the threaded rod  6  in case a large torque is required to clamp a workpiece.  
         [0019]     With reference to  FIG. 2  and  FIG. 1  as well, to clamp a workpiece on the working surface of a machine tool, the inserta clamp is inserted with the cylindrical sleeve  2  into one of the tooling holes  20  on the working surface  21  (partly shown). When the threaded rod  6  is turned downwards against the workpiece, the movable arm  4  will be raised so that shank  1  will be skewed a little bit away from the workpiece. Hence cylindrical sleeve  2  will be pressed against one side of the tooling hole  20  and the frictional force generated should be strong enough to clamp the workpiece on the working surface provided that the outside diameter of the cylindrical sleeve  2  is just a bit smaller than the internal size of the tooling hole  20 . If the outside diameter of the cylindrical sleeve  2  does not match the size of the tooling hole  20 , replace it with another cylindrical sleeve of the right size. The cylindrical sleeve  2  can easily be removed by taking off the taper pin  3 . Multiple inserta clamps can be used at different tooling holes as needed for various shape and sizes of workpieces.  
         [0020]     Referring to  FIG. 3 , to clamp a workpiece on a working surface without tooling holes, the cylindrical mounting base  30  is used. The inserta clamp is inserted with the attached cylindrical sleeve  2  into the cylindrical mounting base  30 , then the outside surface of the cylindrical sleeve  2  is fixed to the upper edge of the mounting base  30  by one or two spot welding  46 . Four screw holes  31  are provided to lock the inserta clamp assembly by screws to anywhere suitable on the working surface of a table, workbench or machine tool. Same method will apply for wooden working surfaces except that different type of screws will be used.  
         [0021]     Again referring to  FIG. 3 , the function of the inserta clamp can be expanded by adding the Y-axis attachment  32  onto shank  1 . The Y-axis attachment  32  comprises two rectangular metal plates  33  and  34  with an elongated slot  35  in the middle of each plate. The two metal plates  33  and  34  are fixed to and separated by two cylindrical blocks  36  and  37 , one at each end of the metal plates. Four screws  38  (only two shown) are used to fix the two metal plates  33  and  34  to the cylindrical block  37 . The other end of metal plates  33  and  34  are welded to cylindrical block  36 . Enclosed inside the metal plates  33 ,  34  and the cylindrical blocks  36 ,  37  is a rectangular block  39  which has a vertical rectangular hole  40  in the middle. The size of hole  40  is just a bit bigger than the cross section of the shank  1  so that shank  1  can be fed through hole  40  and free to slide inside it. On the front and rear sides of the rectangular block  39 , four horizontal flanges  41  (only one shown) are provided to accept the two metal plates  33  and  34 , one on each side. The distance between the two flanges  41  on the same side of the rectangular block  39  is made to fit the height of the metal plates  33  and  34  so that metal plates  33  and  34  are free to slide over the rectangular block  39  within two flanges  41 . Screw  42  is fed through the elongated slot  35  of metal plate  33  and screwed into a threaded through hole on the front side of the rectangular block  39  so that screw  42  can be used to lock the rectangular block  39  and hence the whole Y-axis attachment in position on shank  1 . The design of the screw  42  enables the free sliding of metal plate  33  over rectangular block  39  even when the screw is locking block  39  in fixed position on shank  1 . A threaded hole is equipped along the center axis of cylindrical block  37  to accept the clamping pad  43 . A left-hand threaded hole is provided along the center axis of cylindrical block  36  to feed the left-hand threaded rod  44 . One end of the left-hand threaded rod  44  is equipped with a turning handle  45  and the other end of  44  is pivoted to one side of the rectangular block  39 . When the left-hand threaded rod  44  is turned clockwise with the handle  45 , cylindrical block  36  together with the movable portion of the Y-axis attachment  32  is moved towards the clamping pad  8  on the movable arm  4 . This mechanism provides some means to clamp a second workpiece vertically with clamping pad  43  of the Y-axis attachment  32  against the first workpiece clamped horizontally under the clamping pad  8  of movable arm  4 .  
         [0022]     When the working surface is metallic without tooling holes and when making screw holes for attaching the cylindrical base  30  is not possible, the inserta clamp can be used as shown in  FIG. 4 . A short cylindrical metal tube  50  is spot welded (spot weld  51 ) on the working surface  52  at the location where clamping is required. Then the inserta clamp is inserted with the attached cylindrical sleeve  2  into the short cylindrical metal tube  50 . When the threaded rod  6  is turned downwards against the workpiece, the movable arm  4  will be raised so that shank  1  will be skewed a little bit away from the workpiece. Hence cylindrical sleeve  2  will be pressed against one side of the internal wall of the short cylindrical metal tube  50  and the frictional force generated should be strong enough to clamp the workpiece on the working surface provided that the outside diameter of the cylindrical sleeve  2  is just a bit smaller than the internal diameter of metal tube  50 . If the outside diameter of the cylindrical sleeve  2  does not match the size of metal tube  50 , either replace the sleeve  2  or the metal tube  50  with another one of the right size. The sleeve  2  can easily be removed and replaced by taking off the taper pin as described in the previous paragraphs. Multiple inserta clamps can be used in different locations as needed for various shape and sizes of workpieces. To relocate or remove the present invention after work, the clamping pad  8  is released from the workpiece by turning the handle  7  counterclockwise and hence the friction between the cylindrical sleeve  2  and the short cylindrical metal tube  50  is reduced too. Then the inserta clamp can be removed from the metal tube  50 . The short cylindrical metal tube  50  can easily be removed by breaking the spot weld  51  with a hammer striking it or prying it with a metal rod, then the metal surface  52  can be polished to remove the spot weld residue  51  with suitable power hand tool.