Patent Abstract:
A vise stop for positioning a workpiece in a vise includes a crossbar having a first end, a second end and a mounting surface. The crossbar is attachable to the vise and a first stop arm is pivotally connected to the crossbar first end for positioning a workpiece along an X axis. In the preferred embodiment of the invention, a second stop arm is pivotally connected to the crossbar second end. A friction disc is compressively disposed between an inner face of both the first and second stop arms and the first and second ends of the crossbar. The friction disc allows the stop arm to be frictionally positionable and rotatable about its point of attachment to the crossbar end. The friction disc may be configured as a fiber washer, a spring washer or a compressible o-ring.

Full Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to machine tools and more particularly to a vise stop configured to assure repeatability in the placement of a work piece in relationship to the machine tool. 
     2. Background of the Invention 
     Oftentimes in machining operations, it is necessary to perform repetitious machine tool functions on a plurality of substantially identical parts for mass producing a particular piece or part. Numerically or computer controlled milling machine tools, including mills and lathes, are highly adapted to this type of function. Nevertheless, each new work piece must be set up with particular care to assure that reference surfaces are positioned substantially identically, that is, positioned in the same X, Y &amp; Z axes so as to assure repeatability of the machining operation and quality of the final product. 
     In most machining environments today, a Y axis may be fixed by setting the jaws of a machine tool vise in a specific location and then setting the vice so that the fixed jaw becomes a reference point on the Y axis. Similarly, the seat of the vice, once the vice is installed and bolted to the table of the machine tool, establishes a repeatable reference for the Z axis. Location then of the work piece on the Y axis and repeatability of this location has remained challenging. 
     A number of solutions have been proposed with limitations. In some instances, devices lack rigidity and may loose their ability to produce accurate positioning of piece after piece in relationship to the cutting tool. This is particularly the case where the device or stop is multi-jointed and includes excessive joints and degrees of movement or rotation. Other problems may arise where the vise stop effectively limits access of the machine tool or the cutting tool to various surfaces of the work piece. In some instances, the configuration of the vise stop limits the ability of the cutting tool to access only the top surface of the work piece. 
     What is needed is a simple and effective vise stop which allows repeatability of placement of parts, particularly along the X axis, in relationship to the cutting tool and which allows the work piece to be machined on all surfaces and faces which would otherwise be exposed to the cutting tool. Additionally, the device for locating the work piece should also include the ability to position the stop in relationship to both the vice and the work piece so that it may be moved out of the way when necessary or kept in position as required. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a vise stop for positioning a workpiece in a vise, the vise stop including a crossbar having a first end, a second end and a mounting surface. The crossbar is configured for attachment to the vise and a first stop arm is pivotally connected to the crossbar first end for positioning a workpiece along an X axis. In the preferred embodiment of the invention, a second stop arm is pivotally connected to the crossbar second end. 
     In the preferred embodiment of the invention, a friction disc is compressively disposed between an inner face of both the first and second stop arms and the first and second ends of the crossbar. The friction disc allows the stop arm to be frictionally positionable and rotatable about its point of attachment to the crossbar end. The friction disc may be configured as a fiber washer, a spring washer or a compressible o-ring. This feature of the invention allows an operator the freedom of angularly positioning and repositioning the first and second stop arms as required without loosening the carriage bolt or other means for attaching the first and second stop arms to the crossbar. 
     In the preferred embodiment of the invention, the stop arms each include an adjustable stop tip. A first adjustable stop tip threadedly engages a distal end of the first stop arm, the first adjustable stop tip extending from the distal end of the first stop arm at an angle lying substantially perpendicular to a longitudinal axis of the first stop arm. Similarly, a second stop tip threadedly engages a distal end of the second stop arm, the second adjustable stop tip extending from the distal end of the second stop arm at an angle lying substantially perpendicular to a longitudinal axis of the first stop arm. Both the first and second adjustable stop tips may be locked in position by a locknut. 
     Other advantages will become apparent to those skilled in the art from the following detailed description read in conjunction with the appended claims attached hereto. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective representational view of a machinist&#39;s vise including a vise stop according to the present invention; 
     FIG. 2 is a perspective representational detail view of a machinist&#39;s vise including a vise stop according to the present invention; 
     FIG. 3 is an exploded perspective representational detail view of a machinist&#39;s vise including a vise stop according to the present invention; 
     FIG. 4 is a side representational view of a machinist&#39;s vise including a vise stop according to the present invention; and 
     FIG. 5 is a top representational view of a machinist&#39;s vise including a vise stop according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, vise  10  is shown including vise stop  20 . Vise  10  includes vise body  11 . Fixed jaw  12  extends generally upward from body  11  and opposes movable jaw  14 . Carriage screw  13  is rotatably secured to body  11  and movable jaw  14  is threadedly engaged along the length of carriage screw  13 . Rotatable handle  15  provides a means for advancing movable jaw  14  along the length of carriage screw  13 . Vise stop  20  is shown attached to fixed jaw  12 . 
     Referring to FIG. 2, vise stop  20  is shown attached to fixed jaw  12  of vise  10  by first crossbar attachment screw  25  and second crossbar attachment screw  26 . As shown, vise  10  includes vise body  11  from which fixed jaw  12  extends generally upward. Fixed jaw  12  is shown opposing movable jaw  14 . FIG. 2 shows first stop arm  27  rotatably attached at crossbar first end  22  by first stop arm attachment screw  29 . Similarly, second stop arm  28  is shown rotatably attached at crossbar second end  23  by second stop arm attachment screw  30 . 
     First stop arm  27  includes first adjustable stop tip  35 . First lock nut  37  provides a means for securing first adjustable stop tip  35  at a pre-selected length of adjustment. Similarly, second stop arm  28  includes second adjustable stop tip  36 . Second lock nut  38  provides a means for securing second adjustable stop tip  36  at a pre-selected length of adjustment. 
     FIG. 3 is an exploded perspective view of vise stop  20 . Fixed jaw  12  is shown for reference. Vise stop  20  includes crossbar  21  which is attachable to fixed jaw  12  by first crossbar attachment screw  25  and second crossbar attachment screw  26 . First crossbar attachment screw  25  projects through first crossbar screw aperture  41  for threaded engagement with first fixed jaw threaded engagement aperture  42 . Similarly, second crossbar attachment screw  26  projects through second crossbar screw aperture  43  for threaded engagement with second fixed jaw threaded engagement aperture  44 . 
     Crossbar  21  includes crossbar first end  22  and crossbar second end  23 . First stop arm  27  is rotatably attached at crossbar first end  22  by first stop arm attachment screw  29  and second stop arm  28  is rotatably attached at crossbar second end  23  by second stop arm attachment screw  30 . First friction disc  31  is disposed between crossbar first end  22  and an inner face of first stop arm  27 . First stop arm flat washer  33  is disposed between an outer face of first stop arm  27  and a head of first stop arm attachment screw  29  providing a bearing surface at such interface. When first stop arm attachment screw  29  is torqued to a pre-selected value, first stop arm  27  is frictionally positionable, as first friction disc  31  provides first and second bearing surfaces against which crossbar first end  22  and an inner face of first stop arm  27  may be rotationally offset against one another about first stop arm attachment screw  29 . 
     Similarly, second friction disc  32  is disposed between crossbar second end  23  and an inner face of second stop arm  28 . Second stop arm flat washer  34  is disposed between an outer face of second stop arm  28  and a head of second stop arm attachment screw  30  providing a bearing surface at such interface. When second stop arm attachment screw  30  is torqued to a pre-selected value, second stop arm  28  is frictionally positionable, as second friction disc  32  provides first and second bearing surfaces against which crossbar second end  23  and an inner face of second stop arm  28  may be rotationally offset against one another about second stop arm attachment screw  30 . In either case, the pre-selected torque value for first stop arm attachment screw  29  and second stop arm attachment screw  30  should be in the range of 2-50 ft/lb. and more preferably in the range of 5-25 ft/lb., and in those instances wherein stop arm attachment screw  29  and second stop arm attachment screw  30  have a nominal diameter substantially equal to 0.375″, the torque value should be in the range of 10-20 ft/lb. 
     First adjustable stop tip  35  is shown positioned for engagement through distal end  51  of first stop arm  27  through first stop tip threaded aperture  47 . First lock nut  37  is threadedly engageable with first adjustable stop tip  35  and provides a means for securing first adjustable stop tip  35  so that a pre-selected length of first adjustable stop tip  35  projects through distal end  51  of first stop arm  27  for indexing against a workpiece. 
     Similarly, second adjustable stop tip  36  is shown projecting through distal end  52  of second stop arm  28  through second stop tip threaded aperture  48 . Second lock nut  38  threadedly engages second adjustable stop tip  36  and provides a means for securing second adjustable stop tip  36  so that a pre-selected length of second adjustable stop tip  36  projects through distal end  52  of second stop arm  28  for indexing against a workpiece. 
     First stop arm set screw  39  projects through first set screw aperture  45  for engagement against a threaded outer diameter of first stop arm attachment screw  29  to prevent first stop arm attachment screw  29  from backing out inadvertently. Similarly, second stop arm set screw  40  projects through second set screw aperture  46  for engagement against a threaded outer diameter of second stop arm attachment screw  30  to prevent second stop arm attachment screw  30  from backing out inadvertently. First stop arm set screw  39  and second stop arm set screw  40  are preferably formed of a polymeric material such that the tip will compressively conform against the threaded outer diameter of first stop arm attachment screw  29  or second stop arm attachment screw  30  without causing damage to such threaded components. 
     Referring to FIGS. 4 and 5, vise  10  is shown including vise stop  20 . Vise  10  includes vise body  11 . Fixed jaw  12  extends generally upward from body  11  and opposes movable jaw  14 . Vise stop  20  is shown attached to fixed jaw  12 . Workpiece W 1  is compressively held between fixed jaw  12  and opposing movable jaw  14 . Referring to FIG. 5, carriage screw  13  is rotatably secured to body  11  and movable jaw  14  is threadedly engaged along the length of carriage screw  13 . Rotatable handle  15  provides a means for advancing movable jaw  14  along the length of carriage screw  13 . 
     FIG. 4 shows first stop arm  27  rotatably attached at crossbar first end  22  by first stop arm attachment screw  29 . First stop arm  27  includes first adjustable stop tip  35 , shown in FIG.  3 . First lock nut  37  provides a means for securing first adjustable stop tip  35  at a pre-selected length of adjustment. Machine tool T is shown positioned above workpiece W 1 . 
     Referring to FIG. 5, crossbar  21  includes crossbar first end  22  and crossbar second end  23 . First stop arm  27  is rotatably attached at crossbar first end  22  by first stop arm attachment screw  29  and second stop arm  28  is rotatably attached at crossbar second end  23  by second stop arm attachment screw  30 . First friction disc  31  is shown disposed between crossbar first end  22  and an inner face of first stop arm  27 . First stop arm flat washer  33  is disposed between an outer face of first stop arm  27  and a head of first stop arm attachment screw  29  providing a bearing surface at such interface. Similarly, second friction disc  32  is disposed between crossbar second end  23  and an inner face of second stop arm  28 . Second stop arm flat washer  34  is disposed between an outer face of second stop arm  28  and a head of second stop arm attachment screw  30  providing a bearing surface at such interface. First stop arm  27  includes first adjustable stop tip  35 . First lock nut  37  provides a means for securing first adjustable stop tip  35  at a pre-selected length of adjustment. Similarly, second stop arm  28  includes second adjustable stop tip  36 . Second lock nut  38  provides a means for securing second adjustable stop tip  36  at a pre-selected length of adjustment. 
     Referring to FIG. 4, workpiece W 1  is repeatably locatable along Y axis  55  by placement of workpiece W 1  between fixed jaw face  16  which provides a Y axis reference surface and movable jaw face  17 . Similarly, workpiece W 1  is repeatably locatable along Z axis  57  by placement of workpiece W 1  against upper surface  18  of vise body  11  which provides a Z axis reference surface. 
     FIG. 5 shows workpiece W 1  and workpiece W 2  compressively held between fixed jaw  12  and opposing movable jaw  14 . Workpiece W 1  is repeatably locatable along X axis  56  by positioning workpiece W 1  against first adjustable stop tip  35 . Similarly, workpiece W 2  is repeatably locatable along X axis  56  by positioning workpiece W 2  against second adjustable stop tip  36 . 
     While this invention has been described with reference to the described embodiments, this is not meant to be construed in a limiting sense. Various modifications to the described embodiments, as well as additional embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention.

Technology Classification (CPC): 1