Abstract:
An improved tool is provided for locating the corner or edge of a workpiece while setting the workpiece at a desired angle with respect to a work surface. An elongated arm member slidably engages an elongated base member at one end, allowing for the measurement of the distance between the opposite end portions of the arm and base member and calculation of the angle at which the workpiece is disposed. The base member is provided with generally opposing first and second mating surfaces for locating the corner or edge of the workpiece. Different embodiments are provided for use in finding edges of workpieces having various angles. Different embodiments further provide for the use of multiple measuring instrumentalities and calculations.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to devices capable of positioning and precisely locating an edge of a workpiece relative to the work surface of a machine tool and more particularly to a hand-held device for locating the edge of a workpiece and positioning the workpiece at an angle in relation to the work surface of various work tools such as drills, milling tools, and grinders. 
   2. Description of the Prior Art 
   In machine shops that use milling tools and the like, it is often required to set a part or workpiece on a machine for the purpose of machining the workpiece to a required angle or for inspection. However, when the workpiece is disposed at an angle and the machining is to be performed, the corner or edge of the workpiece is often difficult to locate. 
   Presently, a machinist may use a sine bar or similar device to set the angle of the part. The machinist must then use a second tool to locate the corner or edge of the part in order to proceed with the machining operation. Typically, a machinist may take a steel ball or other such spherical object and remove one quadrant of the sphere to form a tool for locating the edge of the workpiece. This type of tool is frequently referred to as a “Pac Man” ball because of its resultant shape. In use, the Pac Man ball is placed on the corner of the workpiece, and an Indicator is “swung” at the periphery (or as close as practical) of the ball to align the spindle of the machine with the corner of the part. 
   U.S. Pat. No. 5,046,262 discloses a spherical edge locator that is used in the manner described above for locating an edge of a workpiece. While the spherical edge locator is more refined than the Pac Man ball, it lacks the ability to set the angle of the workpiece. 
   Accordingly, the shortcomings of the prior art make it necessary to use more than one device and at times more than one person in order to locate an edge or corner on a workpiece while setting it at the desired angle. Accordingly, what is needed is a simple hand tool that is easy to use for locating the edges and corners of workpieces as well as setting the angle of the workpieces with respect to a working surface. 
   SUMMARY OF THE INVENTION 
   A device for locating the edge or corner of a workpiece is provided with an elongated base member having opposite ends and upper and lower surfaces. The lower surface of the base member is provided with first and second mating surfaces for releasably engaging first and second planar surfaces of the workpiece. In one embodiment, the first and second mating surfaces of the base member are disposed in a fixed perpendicular relationship with one another for locating a 90° corner or edge of the workpiece. In another embodiment, a plate member is slidably engaged with the base member at one end. In use, the base member is placed adjacent the workpiece, and the plate member is slid outwardly from the base member in a semicircular fashion until it engages the second planar surface of the workpiece. The plate member allows the device to locate the corner or edge of a workpiece of greater or less than 90°. 
   The device is further provided with an elongated arm having upper and lower surfaces. The lower surface of the arm is slidably engaged with the top surface of the base member at one end. In one embodiment, the arm and base members are slidably engageable with one another to permit the insertion of gauge blocks or similar structures between the opposing end portions of the arm and base members. To set the workpiece at a desired angle with respect to the work surface, the sine of the desired angle is calculated and then multiplied by a constant, which is associated with the subject device. The calculation provides the user with the size of gauge blocks required to be disposed between the arm and base members. Once the gauge blocks are in position, a level vial, disposed within the upper surface of the arm member is used to level the device, thus disposing the workpiece at the desired angle. 
   In another embodiment, the opposing end portions of the arm and base members are shaped for use with a micrometer or similar tool to adjust the arm member with respect to the base member. Once the arm and base members are in position, a level vial provided in the upper surface of the arm member is used to level the device, orienting the workpiece at the desired angle. 
   Various combinations of the above embodiments provides for a hand-held tool for locating the edge or corner of a workpiece and disposing the workpiece at a desired angle with respect to a work surface. 
   Accordingly, it is one of the principal objects of the present invention to provide an improved tool for use in locating the edge or corner of a workpiece. 
   It is a further object of the present invention to provide a hand tool for setting the angular relationship of a workpiece with respect to a work surface. 
   Yet another object of the present invention is to provide an improved tool that can both locate the edge or corner of a workpiece and set the workpiece at a desired angle with respect to a work surface. 
   Still another object of the present invention is to provide a tool for locating the edge or corner of a workpiece and setting the angular relationship of the workpiece with respect to a work surface that is compact and easily portable. 
   A further object of the present invention is to provide an improved tool for locating the corner or edge of a workpiece and disposing the workpiece at a desired angle with respect to a work surface that is easy to operate. 
   These and other objects will be apparent to those skilled in the art. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevation view of one embodiment of the present invention as the same would be used to find the 90° corner or edge of a workpiece while setting the workpiece at a desired angle with respect to a work surface; 
       FIG. 2A  is a perspective view of the embodiment of the present invention of  FIG. 1 ; 
       FIG. 2B  is an exploded perspective view of the embodiment of the present invention of  FIG. 1 ; 
       FIG. 3  is a side elevation view of another embodiment of the present invention as the same could be used to locate the corner of a workpiece that is greater than 90° while setting the workpiece at a desired angle with respect to a work surface; 
       FIG. 4A  is a perspective view of the embodiment of the present invention of  FIG. 3 ; 
       FIG. 4B  is a perspective exploded view of the embodiment of the present invention of  FIG. 3 ; 
       FIG. 5  is another embodiment of the present invention as the same could be used to find the 90° corner or edge of a workpiece while setting the workpiece at a desired angle with respect to a work surface; 
       FIG. 6A  is a perspective view of the embodiment of the present invention of  FIG. 5 ; 
       FIG. 6B  is a perspective exploded view of the embodiment of the present invention of  FIG. 5 ; 
       FIG. 7  is a side elevation view of another embodiment of the present invention as the same could be used to locate the corner of a workpiece that is less than 90° while setting the workpiece at a desired angle with respect to a work surface; and 
       FIG. 8A  is a perspective view of the embodiment of the present invention of  FIG. 7 ; 
       FIG. 8B  is a perspective exploded view of the embodiment of the present invention of FIG.  7 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The tool of this invention is referred to generally by the reference numeral  10  and includes a base member  12  having a first end portion  14 , a second end portion  16 , and upper surface  18  and lower surface  20 . The lower surface  20  is provided with a first engagement face  22  and a second engagement face  24 . The second engagement face  24  is preferably provided with one or more magnets  26  that are disposed flush within the second engagement face  24 . 
   The tool  10  is further provided with an arm member  28  having a first end  30 , a second end  32 , an upper surface  34 , and a lower surface  36 . The lower surface  36  of the arm member  28  is pivotably connected to the upper surface  22  of the base member  12  so that the second end portion  32  of the arm member  28  can be selectively moved between generally open and generally closed positions with respect to the second end portion  16  of the base member  12 .  FIG. 1  depicts the tool  10  with the arm member  28  in a generally open position. 
   Although it is contemplated that the arm member  28  and the base member  12  could be pivotably coupled together using a pivot pin or similar structure, it is preferred that the first end  14  of the base member  12  be generally disc-shaped and the lower surface  36  of the arm member  28  be provided with a generally circular collar  38  adjacent the first end  30 . The collar portion  38  is sized to pivotably slidably receive the disc-shaped first end  14  of the base member  12 . A set pin  40  is provided to be disposed through an elongated opening  42  formed in the first end  30  of the arm member  28  and be secured to the first end  14  of the base member  12 . The set pin  40  assists in the alignment of the arm member  28  with respect to the base member  12  and further limits the pivoting range of motion between the two structures. A bolt member  44  is preferably provided to be disposed through an opening  46  formed in the arm member  28  and into the elongated opening  48  formed within the first end portion  14  of the base member  12 . The bolt member  44  is releasably engaged by a receiving member  50  disposed within the elongated opening  48 . Accordingly, tensioning of the bolt member  44  with respect to the receiving member  50  tightens the frictional engagement between the disc-shaped first end  14  of the base member  12  with the collar portion  38  to secure the position of the arm member  28  with respect to the base member  12 . 
   The tool  10  depicted in  FIGS. 1 ,  2 A,  2 B,  5 ,  6 A and  6 B is shown having a first engagement face  22  and second engagement face  24  that are set in a 90° position with respect to one another. However, in an alternate embodiment, the tool  10 ′ is provided with a plate member  52  that is slidably connected to the first end portion  14  of the base member  12 . The plate member  52  is preferably semicircular in shape so that it will move in an arcing path outwardly from the base member  12 . The plate member  52  is provided with opposite side portions  54  and  56 . In its preferred engagement with the base member  12 , the side portion  54  of plate member  52  forms at least a portion of the first engagement face  22 . Accordingly, with the use of plate member  52 , the angular relationship of first engagement face  22  with respect to second engagement face  24  can be selectively positioned between angles ranging from 0° to  1800 . However, an optional plate member  52 ′ can be provided in place of plate member  52 . Plate member  52 ′, while semicircular, actually completes three-quarters or more of a circular shape. Plate member  52 ′ is preferably used for disposing the first engagement face  22  with respect to the second engagement face  24  at angles less than 90°. A bolt member  54  is provided for connecting plate members  52  and  52 ′ to the first end  14 ′ of the base member  12 ′. The bolt member  54  further serves as a structure for aligning and limiting the movement of the plate members  52  and  52 ′ with respect to the base member  12 ′.  FIG. 3  depicts one possible manner in which the tool  10 ′ can be so adjusted. 
   In use, the tool  10  of the present invention is useful for quickly and easily locating the corner or edge of a workpiece  58  and then setting the angle at which the workpiece  58  is disposed with respect to a work surface  60 . To locate the corner or edge of the workpiece  58 , the lower surface  20  of the base member  12  is positioned closely adjacent the workpiece  58  so that the first engagement face  22  is positioned closely adjacent a first generally planar surface  62  of the workpiece  58 , and the second engagement face  24  is closely adjacent a second generally planar surface  64  of the workpiece  58 . With the tool  10  in this position, the corner or edge of the workpiece is easily located at the point where the first engagement face  22  and the second engagement face  24  meet. For those applications where the workpiece has a corner or edge that is greater or less than 90°, the plate member  52  or  52 ′ is simply moved in an outward direction from the base member  12 ′ until the first engagement surface  22  is positioned closely adjacent the first generally planar surface of the workpiece  58 . 
   To set the angle of the workpiece  58  with respect to the work surface  60  using the tool  10  or  10 ′, the user first calculates the sine of the desired angle. For example purposes, the workpiece  58  depicted in  FIGS. 1 and 3  is set at an A° angle with respect to the work surface. The sine of the angle can be calculated using a calculator or other such processing device or simply obtained from a standard sine table. 
   The arm member  28  has a known functional length, which in this example, depicted in  FIGS. 1 and 3 , is 2 inches (measured from a point representing the center of the circular portion of first end portion  30  to the second end portion  32 ). It is contemplated that the functional length of the arm member  28  and the remaining dimensions of the tool  10  could be provided in virtually any size. It is preferred, however, that the dimensions chosen provide a compact tool for use and a functional length that will simplify the calculations performed using this method. The sine of the angle must be multiplied by the functional length of the arm member  28 . The resulting number represents the distance “D” in which the second end  32  of the arm member  28  must move away from the second portion  16  of the base member  12 . The arm member  28  is preferably moved the derived distance from the base member  12  using one or more gauge blocks or other similar structure having a precise known thickness. With the arm member  28  in its generally open position with respect to the base member  12 , the bolt member  44  can be used to secure the position. 
   The tool  10  is then positioned closely adjacent the workpiece  58 , locating the edge to be aligned with the work surface. The workpiece  58  is then lifted to increase its angular relationship with respect to the work surface  60  until the arm member  28  is substantially horizontally disposed. A level vial  68  can be secured within the arm member  28  to provide the user with a quick method of orienting the tool  10  and the workpiece  58 . The degree of accuracy required by the task at hand will dictate the type of level vial used. Once the arm member  28  is substantially horizontally disposed, the user may indicate the ledge  29  of the arm member  28  to accurately align the workpiece  58  with the axis of the machine being used and, thus, the angle of the workpiece has been set. It will be clear to those of skill in the art that the accuracy of the angular disposition of the workpiece is dependent upon the horizontal disposition of the work surface  60  when the level vial  68  is used exclusive of an indicator. However, in such cases and to the extent that the work surface  60  is not substantially horizontal, the level vial  68  should be calibrated accordingly. With the final position being set, indicating the alignment member  31  aligns the spindle of the machine with the corner of the workpiece  58 . 
   In another embodiment, the tool  10 ″ provides an alternate means for setting the angular relationship of the workpiece  58  with respect to the work surface  60 , as depicted in  FIGS. 5-8B . The substantial differences between the tool  10 ″ and the tool  10  can be seen in the shape of the second end portion  32 ″ of the arm member  28 ″ and the second end portion  16 ″ of the base member  12 ″. The function and structure of the tool  10 ″ and tool  10 ′″ for locating the edge or corner of the workpiece  58  is essentially the same as the structure and function of tool  10  and tool  10 ′ hereinabove. 
   To set the angular relationship of the workpiece  58  with respect to the work surface  60  using tool  100 ″ or tool  10 ′″, the desired angle (“A”) is inserted into the formula (sine (A°/2)*R+r)*2), which is derived from the geometry and size of the tool  10 ″ as shown in FIG.  5 . The resulting number provides the user with the distance “D” representing the distance in which the second end portion  32 ′″ of the arm member  28 ′″ should be moved away from the second end portion  16 ′″ of the base member  12 ′″. This dimension can be set using a micrometer or other similar device. With the arm member  28 ′″ in its generally open position, the bolt member  44  can be tightened to secure the final position. The tool  10 ′″ is then positioned closely adjacent the workpiece  58  to locate the edge. Magnet  26  will help secure the position of the tool  10 ′″ with respect to a metal workpiece. The workpiece  58  is then lifted to increase the angular relationship of the workpiece  58  with respect to the work surface  60  until the arm member  28 ′″ is substantially horizontally disposed. As discussed hereinbefore, a level vial can be used to quickly set the workpiece  58 , indicating the ledge  29 ′″ to accurately align the workpiece  58  with the machine axis, achieving a final position. 
   In the drawings and in the specification, there have been set forth preferred embodiments of the invention; and although specified items are employed, these are used in a generic and descriptive sense only and not for purposes of limitation. Changes in the form and proportion of parts, as well as substitute of equivalents, are contemplated as circumstances may suggest or render expedient without departing from the spirit or scope of the invention as further defined in the following claims. 
   Thus, it can be seen that the invention accomplishes at least all of its stated objectives.