Patent Publication Number: US-7219885-B2

Title: Sliding rack L-clamp having a non-rotating shaft

Description:
This application claims the benefit of U.S. Provisional Patent Application No. 60/606,758, filed Sep. 2, 2004. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention generally relates to L-clamps. Particularly, the present invention relates to a sliding rack L-clamp. 
   2. Description of the Prior Art 
   A standard L-clamp or bar clamp has a straight bar attached to a fixed arm. A sliding arm slides along the straight bar and the outer end of the sliding arm comprises a threaded screw which comprises a handle on one end and a pad on the other end. When the handle is turned, the pad engages an object being clamped between the pad on the end of the threaded screw and the pad on the end of the fixed arm. However, as the screw is turned the pad at the end of the screw rotates generally causing marring of the object or walking movement or deflection of the screw on the object being clamped. 
   The related prior art includes U.S. Pat. No. 6,367,790 (2002, Ocklenburg et al.) which discloses a sliding arm L-clamp comprising a bar, an elbow, and an arm. The movable arm extends from the bar, slides along the bar, and has an outer end which is threaded to a spindle carrying a handle or crank at one end and a first abutment pad at the opposite end. The fixed arm carries at its outer end a second abutment pad parallel with the first abutment pad. However, as the spindle turns, the abutment pad turns creating the possibility of marring a workpiece being held in the L-clamp. 
   U.S. Pat. No. 5,893,553 (1999, Pinkous) discloses a C-shaped clamp having a pad that does not rotate when an elongated threaded rod with an extendible thread surface is screwed toward a ball jointed pad on the opposite end of the C-clamp device. The elongated threaded rod is attached to the top of a pad bracket and a bar means attaches to an end of the pad bracket perpendicular to the rod. The blocking rod prevents the pad bracket from rotating. However, this design does not support the exterior spindle and still allows for pad and spindle rotation, albeit limited. 
   U.S. Pat. No. 5,405,124 (1995, Mayer) discloses a sliding arm C-shaped clamp bow with a nonrotating pad or clamping body. A clamping spindle is threaded through a spindle nut at one end of the bow. The contact surface of the end of the spindle is secured within the clamping body so that as the contact surface of the spindle rotates within the clamping body, the surface clamping element remains stationary. The clamping body extends from the guide section along the clamp bow. However, this is a C-shaped clamp with a spindle and not an L-clamp and the exposed spindle is unsupported by an exterior housing. 
   Therefore, what is needed is a sliding arm L-clamp that does not rotate when being tightened. What is further needed is an L-clamp that prevents marring of a workpiece, walking movement, or deflection of a screw on a workpiece when tightening the L-clamp on a workpiece. What is still further needed is an L-clamp that provides fast clamping of a workpiece. 
   SUMMARY OF THE INVENTION 
   It is an object of the present invention to provide a sliding arm L-clamp having a pad on the end of a cylindrical tube of the sliding rack that does not rotate when being tightened for holding a workpiece. It is another object of the present invention to provide a sliding arm L-clamp having a non-rotating shaft or inner tube to prevent marring of a workpiece, walking movement, or deflection of a screw on a workpiece when tightening the L-clamp on a workpiece. It is a further object of the present invention to provide fast clamping of a workpiece by sliding a rack along an L-clamp and turning a hex nut on one end of a cylindrical tube which turns a screw rod inside the tube thereby tightening a pad of the sliding rack quickly on the workpiece. 
   The present invention achieves these and other objects by providing a sliding rack L-clamp for clamping a workpiece having a first clamp means and a second clamp means. First clamp means has an L-shaped bar, and second clamp means has a rack, a cylinder assembly, a pad, a screw rod, and a linear actuating mechanism. The linear actuating mechanism is operably connected to the cylinder assembly. The L-shaped bar has an arm and a rail. The arm and rail form approximately a ninety degree angle. The arm has a flat portion on one end, i.e. the flat arm end, for contacting the workpiece. 
   The rack has an opening on a first end for slidably receiving the rail of the L-shaped bar therethrough. The cylinder assembly, which is mounted perpendicular to the rack on a second end of the rack and which is axially aligned with the flat arm end, includes an outer tube and a nonrotatable inner tube. The pad attaches to a first end of the inner tube opposite the flat portion of the arm of the L-shaped bar. 
   The linear actuating mechanism is operably attached to a second end of the inner tube for moving the pad back and forth when a torque providing means engages the linear actuating mechanism for clamping the workpiece. The linear actuating mechanism includes a screw rod, an end cap, a threaded insert, a hex nut, a spring pin, and an optional handle. The end cap attaches within the outer tube. The threaded insert has a first end attached, preferably by a press-fit, into the second end of the inner tube. The screw rod has a threaded portion and a rod end portion. The screw rod is threaded into the threaded insert with a major portion of the threaded portion of the screw rod extending through the threaded insert and into the inner tube. The end portion extends through the end cap. The hex nut receives the end portion of the screw rod and a spring pin passes through the hex nut and the end portion of the screw rod to secure the screw rod within the cylinder assembly. 
   The objects are further accomplished by an L-shaped bar having an arm and a rail forming approximately a ninety-degree angle, an adjustable sliding rack assembly having a rack with an opening in a first end for receiving the rail of the L-shaped bar and a cylinder assembly attached to a second end of the sliding rack, the cylinder assembly having a first end for contacting a workpiece as the sliding rack is moved toward the arm of the L-shaped bar, and a linear actuating mechanism attached to the second end of the cylinder assembly for extending and retracting the first end of the cylinder without rotating the first end of the cylinder. 
   Additional objects, features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The appended claims particularly point out and distinctly claim the subject matter of the present invention. The various objects, advantages, and novel features of the present invention will be more fully apparent from a reading of the following detailed description in conjunction with the accompanying drawings in which like reference numerals refer to like parts. 
       FIG. 1  is a side elevational view of a sliding arm L-clamp having a non-rotating abutment pad according to the present invention. 
       FIG. 2  is a side perspective view of an L-clamp having a non-rotating abutment pad according to the present invention showing workpieces of a block and a board, in phantom, held together by the L-clamp. 
       FIG. 3  is a cross-sectional view of a cylinder of the L-clamp of  FIG. 1 . 
       FIG. 4  is an end view of the outer tube of the cylinder of  FIG. 3 . 
       FIG. 5  is an end view of an inner tube of the cylinder of  FIG. 3 . 
       FIG. 6  is a cross-sectional view of an Acme nut of the cylinder of  FIG. 3 . 
       FIG. 7  is a side elevational view of a screw rod of the cylinder of  FIG. 3 . 
       FIG. 8  is a top view of a rack of the L-clamp of  FIG. 1 . 
       FIG. 9  is a top plan view of the L-clamp of the present invention. 
       FIG. 10  is a front elevational view of the L-clamp of the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The preferred embodiment(s) of the present invention is illustrated in  FIGS. 1–10 .  FIG. 1  illustrates a side elevational view of a sliding rack L-clamp  10  having an L-shaped bar  11  and an adjustable rack assembly  15 . Adjustable rack assembly  15  includes a rack  16 , a cylinder assembly  18 , a non-rotating pad  20 , and a linear actuating mechanism  50  of which only a portion is shown as a hex nut  24  with an optional handle  26 . L-shaped bar  11  has a rail  12  and an arm  14  forming a right angle or an L-shape. At the end of arm  14  on an inner side is a flat arm end  22 . Rack  16  includes an opening  17  (not shown) at a first rack end  16   a  for receiving rail  12  of L-shaped bar  11 . On the other end of rack  16 , i.e. second rack end  16   b , is cylinder assembly  18  having a pad  20  at one end. Cylinder assembly  18  includes an outer tube  34  and a nonrotatable inner tube or shaft  36 . Pad  20  is attached to a first inner tube end  36   a  of inner tube or shaft  36 , which extends from a first outer tube end  34   a  of outer tube  34  when a hex nut  24  located adjacent a second outer tube end  34   b  of outer tube  34  is rotated by a handle  26 . Pad  20  preferably has a short cylindrical shaft (not shown) having external threads which screws into inner tube or shaft  36 . 
   Optional handle  26  is slidably received through an opening in hex nut  24 , and a cap  28  screws onto one end of handle  26  to retain the handle  26 . The other end  29  of handle  26  is knurled so that it does not enter hex nut  24 . Pad  20  does not rotate as it extends from cylinder assembly  18  from a proximal position adjacent outer tube end  34   a  to a distal position adjacent flat arm end  22  thereby avoiding marring the workpiece  30 , walking on the workpiece  30 , or causing any deflection of cylinder assembly  18  on the workpiece  30 . When handle  26  is removed from hex nut  24 , a power tool or a manual wrench may be used to turn hex nut  24 . 
   Referring to  FIG. 2 , a perspective view of L-clamp  10  having non-rotating pad  20  is shown clamping a first workpiece  30  to a second workpiece  32 . Pad  20  contacts the first workpiece  30  and flat end  22  of arm  14  of L-shaped bar  11  contacts the second workpiece  32 . Rail  12  is inserted in opening  17  of rack  16  and pad  20  on the end of shaft  36  has been extended by turning handle  26  to hold the first workpiece  30  in contact with the second workpiece  32 . 
   Referring to  FIG. 3 , a cross-sectional view of the cylinder assembly  18  is shown. Cylinder assembly  18  includes an outer tube  34 , shaft or inner tube  36 , having pad  20  attached at first inner tube end  36   a , and linear actuating mechanism  50  operably connected to outer tube  34  and inner tube  36 . Linear actuating mechanism includes a threaded insert  38 , preferably an Acme nut, a screw rod  40 , hex nut  24 , a spring pin  25   a , an end cap  42 , and optional handle  26 . Screw rod  40  is rotated by hex nut  24  or by handle  26  passing through hex nut  24 . Rack  16  is welded to the outer wall of outer tube  34  near first outer tube end  34   a  where pad  20  is located. 
   End cap  42  attaches within second outer tube end  34   b  of outer tube  34  by threading or press fitting. Threaded insert  38  has a first end  38   a  attached, preferably by a press-fit, into the second inner tube end  36   a  of inner tube  36 . Screw rod  40  has a threaded portion  41   a  and an end portion  41   b . Screw rod  40  is threaded into threaded insert  38  with a major portion of threaded portion  41   a  of screw rod  40  extending through threaded insert  38  and into inner tube  36 . End portion  41   b  extends through end cap  42 . Hex nut  24  receives end portion  41   b  of screw rod  40  and spring pin  25  passes through hex nut  24  and end portion  41   b  of screw rod  40  to secure screw rod  40  within cylinder  38 . 
   Referring to  FIG. 4  and  FIG. 5 ,  FIG. 4  is an end view of outer tube  34  and  FIG. 5  is an end view of inner tube  36  that is slidably received within outer tube  34 . Outer tube  34  includes a notch or groove  35  along its entire length. Inner tube  36  includes a ridge or protrusion  37  on the outside of inner tube  36  along its entire length. Ridge  37  is configured to be slidably received within groove  35  of outer tube  34 . 
   Referring now to  FIG. 6 , there is illustrated a cross-sectional view of threaded insert  38  shown in  FIG. 3 . Threaded insert  38  has a shoulder portion end  38   a , a smaller diameter shaft portion  38   b , and internal threads  38   c . Internal threads  38   c  are preferably left hand threads. As previously disclosed, threaded insert  38  is preferably an Acme nut. Shaft portion  38   b  is preferably press-fitted into the second inner tube end  36   b  of inner tube or shaft  36 , but may also be threaded, welded, pinned, and the like, to secure threaded insert  38  into shaft  36 . Screw rod  40  is screwed into threaded insert  38 . When screw rod  40  is rotated, threaded insert  38  rides along the threads of screw rod  40  causing inner tube or shaft  36 , which is attached to threaded insert  38 , to move in and out of outer tube  34  of cylinder assembly  18  by way of first outer tube end  34   a . Inner tube  36  cannot rotate due to its outer ridge  37  lying within groove  35  of outer tube  34 . 
     FIG. 7  is a side elevational view of screw rod  40 . Screw rod  40  includes threaded portion  41   a  and end portion  41   b . As noted, threaded portion  41   a  extends over a major portion of screw rod  40 . End portion  41   b  is shown having two levels of reduced diameters, a first reduced diameter  44  and a second reduced diameter  46 . Second reduced diameter includes a through opening  48 . First reduced diameter  44  extends through end cap  42  of cylinder  18 . As previously disclosed, end cap  42  preferably screws into threads on the inside diameter of outer tube  34 . Second reduced diameter  46  extends through end cap  42  and into the middle of hex nut  24 . Hex nut  24  also includes a small cylindrical opening  25  that is aligned with a through opening  48  in second reduced diameter  44  of screw rod  40 . A spring pin  25   a  is inserted into through opening  48  for retaining the hex nut  24  on end portion  41   b  of screw rod  40 . 
   Referring to  FIG. 8 , a top view of rack  16  of L-clamp  10  is shown comprising opening  17  for receiving rail  12  of L-shaped bar  11  to pass through in order to facilitate quickly securing workpieces such as workpieces  30 ,  32  in  FIG. 2 . Rack  16  slides along rail  12  freely until clamping pressure is applied, at which time a binding of rack  16  and rail  12  prevents movement. The opposite end of rack  16  is attached to cylinder assembly  18  which houses inner tube or shaft  36  with pad  20  on first inner tube end  36   a  of shaft  36  for contacting workpiece  32 . 
   Referring to  FIG. 9  and  FIG. 10 ,  FIG. 9  is a top plan view of L-clamp  10  showing arm  14  of L-shaped bar  11 .  FIG. 10  is a front elevational view of L-clamp  10  showing the end of arm  14  having flat end  22  for contacting workpiece  32  and pad  20  for contacting workpiece  30  as shown in  FIG. 2 . A front portion of rail  12  of L-shaped bar  11  is shown between flat portion  22  of arm  14  and pad  20 . 
   Although the preferred embodiments of the present invention have been described herein, the above description is merely illustrative. Further modification of the invention herein disclosed will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the invention as defined by the appended claims.