Patent Abstract:
An apparatus for improving the accuracy of machines which shear plate materials in general and sheet metals in particular. The apparatus comprises an indicator that is magnetically mounted to the shearing blade and extends downward toward the work table of the machine to give an indication of where the blade will pass through the metal.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Applications for which benefit is being claimed: 
         [0002]    1. Provisional application No. 62/283,778 filed by William D. Rogers and Richard D Rogers entitled Plate Shear Guide Bars (Line Finder) on Sep. 10, 2015. 
         [0003]    2. provisional application No. 62/390,764 filed by William D Rogers and Richard D Rogers on Apr. 8, 2016 entitled Line Finder and Holding System for Brakes and Shears. 
     
    
     BACKGROUND OF THE INVENTION 
       [0004]    Manufacturing of metal goods has long been an important part of our national economy and a major source of our national wealth. As competition from a global economy pressures our manufacturing base, it becomes extremely important that metal working machines be improved in productivity, accuracy and quality of work produced. One such group of machines are metal brakes, coper notchers, and particularly, shears. At present, sheet metal shears, although adequate in most respects, are difficult with regard to accuracy of cut. These machines consist primarily of two knives, one movable and one stationary. In most cases the lower knife is stationary and the upper knife is moved up and down. In order to accommodate materials of different thickness, there must be a considerable amount of space between the two knives while the machine is at rest. In order to minimize the force needed to make the cut, the upper, moving knife must have a cutting surface that is at an angle, called a rake angle, with respect to the lower, stationary knife. These factors leave the operator with no way to align the cut other than viewing and aligning with the edge of the lower knife. Often the plate is as wide as the bottom blade leaving it totally hidden. The cutting line on which the stock is to be sheared is, of course, drawn on the top surface of the stock. It is not possible for the operator to look straight down at the stock being sheared as the knives are recessed within the machine for safety and other purposes, therefore the operator must guess at the proper alignment. As thickness of stock being sheared increases, the difficulty of alignment increases. The result is lost work time and ruined material, decreasing the quality of work and the efficiency with which it is done. The manufacturer is left with a great need for a more efficient method of alignment. The present invention fulfills this need by providing a tool by which the desired line of cut by a sheet metal shear or similar device can easily and accurately be obtained. 
       DESCRIPTION OF THE PRIOR ART 
       [0005]    At present, accurate cutting with shearing machines is accomplished by use of an apparatus mounted behind the cutting knife which provides a stop for the material being sheared. Such devices require adjustment for individual cuts. In addition, these devices provide only for square cutting and do not accommodate cutting stock at an angle. Solutions to these problems were offered in the provisional application No. 62/283,778 filed by William D. Rogers and Richard D Rogers entitled Plate Shear Guide Bars (Line Finder) on Sep. 10, 2015. Further solutions were offered in the provisional application No. 62/390,764 filed by William D Rogers and Richard D Rogers on Apr. 8, 2016 entitled Line Finder and Holding System for Brakes and Shears. These solutions are further addressed by this application. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a front elevation view of the shear alignment tool mounted to a sheet metal shear. 
           [0007]      FIG. 2  is a side elevation view of the shear alignment tool showing the angle of sight of an operator. 
           [0008]      FIG. 3  is a side elevation view showing two shear alignment tools affixed to a shear, one to the front side of the upper knife, and one to the back side of the lower knife. 
           [0009]      FIG. 4  is a front elevation view of the two-shear alignment tool mounting arrangement. 
           [0010]      FIG. 5  is a front elevation view of an elongated shear alignment tool equipped with a level. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    Referring to the drawings and more specifically to figure one, it can be seen that the shear alignment tool  1  comprises essentially a base  2 , a set of facial magnets  3  imbedded into base  2 , and two adjustment screws  4 . Base  2  is formed from non-magnetic material such as aluminum or plastic. This assures that the magnetic attraction is applied at the proper place and keeps magnetic waste materials from clinging to the tool. Facial magnets  3  are positioned in base  2  so as to make contact and thus magnetically adhere to upper knife  5 . Adjustment screws  4  are so adjusted so as to make contact with frame  6  located above upper knife  5  while providing the desired opening between line identifying edge  7  of shear alignment tool  1  and lower knife  8 . Adjustment screw magnets  9  are affixed to the upper ends of adjustment screws  4 . These magnets affix the upper ends of adjustment screws  4  to frame  6 . In some shears, frame  6  may not be located or formed in a suitable way to accommodate adjustment screws  4 . In such a case, a special adapter bar may be mounted on the shear for this purpose. Both frame  6  and lower knife  8  are immovable thus the position of line identifying edge  7  above lower knife  8 , as determined by adjustment screws  4 , is maintained. Through the use of adjustment screws  4 , the space between line identifying edge  7  and lower knife  8  is set to be just larger than the thickness of the material being sheared. Upper knife  5 , lower knife  8 , and line identifying edge  7  are in the same vertical plane. Line identifying edge  7  is also set to be parallel to lower knife  8  so as to maintain a constant space width. By producing this small, even space between line identifying edge  7  and lower knife  8 , the rake angle is effectively eliminated and the distance between upper knife  5  and lower knife  8  is effectively reduced to a manageable level for the operator. As upper knife  5  lowers during the shearing process, shear alignment tool  1  continues to magnetically adhere to upper knife  5  as the surface of upper knife  5  slides along the shear alignment tool  1 . Shear alignment tool  1  is maintained at its fixed position by way of sliding action of upper knife  5  against facial magnets  3  and by the fixed position magnets  9 . During reset of upper knife  5 , adjustment screws  4  force shear alignment tool  1  to maintain its position relative to lower knife  8 , returning the setting to its rest position. 
         [0012]    Also referring to figure one, it can be seen that close hold down accessory  10  is affixed to shear alignment tool  1 . Hold down adjustment screw  11  can be adjusted so as to contact, or nearly contact, the surface of the stock being sheared. Close hold down provides a means for holding material stationary after it becomes too short to reach the OEM standard hold down mechanism. This will allow the use of remnants now thrown in the scrap bin. 
         [0013]    Referring to figure two, it can be seen that the bottom of shear alignment tool  1  is tapered so as to produce a very thin lower line identifying edge  7 . As the operator uses shear alignment tool  1 , he can ascertain his line of sight  12  according to his height and posture. Through the skill naturally acquired and the freedom from blockage provided by the tapered line identifying edge  7 , the space between line identifying edge  7  and the stock being sheared is further negated for a near perfect shear. Also depicted are upper knife  5 , lower knife  8 , frame  6 , and work table  14 . For simplification, close hold down accessory  10  is not depicted. 
         [0014]    Referring to figure three, it can be seen that two shear alignment tools  1  may be used in order to obtain an accurate shear while shearing wide pieces of plate. Again for simplification, close hold down accessory  10  is not depicted. In figure three, one of the shear alignment tools  1 A is mounted and used as described above. Another shear alignment tool  1 B is placed on the back side of lower knife  8  and affixed magnetically to lower cutting edge  13  of upper knife  5  by way of adjustment screw magnets  9  and to lower knife  8  by the attraction of facial magnets  3 . The rake angle of upper knife  5  is shown in the drawing as hashed lines. This angle may cause shear alignment tool  1 B to be mounted in a tilted position relative to lower knife  8 . Further adjustment of adjustment screws  4  may be made in order to obtain a level position if desired. A tilted position poses no operational problem as side edge  15  of shear alignment tool  1 B, due to its tilted position, will move away from the edge of the stock being sheared as upper knife  5  moves it downward. This allows shear alignment tool  1 B to move up and down with the movement of upper knife  5  while maintaining contact with lower knife  8 . Adjustment screw magnets  9 , maintaining contact with upper knife  5  assured the return of shear alignment tool  1 B to its rest position after the shear is complete. This gives the operator an indication of the location of the knives that can be seen from a distance as well as an angle. Through this placement of shear alignment tools, the operator may use line identifying edge  7  to align the stock in front of him while using the side edge  15  of shear alignment tool  1 B for the alignment of the stock far to his left or right. The operator may also look from the side of both shear alignment tools, using the very edge of both tools to acquire a near perfect setting along the line to be sheared. Likewise, in the one shear alignment tool application, a series of arches or notches may be cut into the bottom of shear alignment tool  1 . In this case, a series of views of the absolute position of line identifying edge  7  with regard to the layout line on which the stock is being sheared is provided. 
         [0015]    Referring to figure four, it can be seen that shear alignment tool  1 B is affixed to the rear of lower knife  8  and being held in place magnetically by adjustment screw magnets  9 . It can also be seen that shear alignment tool  1 A is magnetically affixed to upper knife  5  and held fast to frame  6  by adjustment screw magnets  9 . As upper knife  5  lowers to make the cut, shear alignment tool  1 B slides along lower knife  8  and shear alignment tool  1 A remains fixed as upper knife  5  slides along its surface. After the shear is made, as upper knife  5  raises, shear alignment tool  1 B is returned to its rest position. The position of shear alignment tool  1 A remains fixed as upper knife  5  regains its relative position with shear alignment tool  1 A. 
         [0016]    Shear alignment tools  1 A and  1 B may also be used wherein both tools are located on the operator&#39;s side of the shear. In fact, it is often advantageous to use multiple tools in this configuration, especially when wide sheets of stock are being sheared. Also, shear alignment tools of different lengths may be employed, depending upon the needs of the operator. In such uses, it is important that the entire line identifying edge be parallel to the cutting edge of lower knife  8  in order to obtain an accurate cut. In figure five, it can be seen that this is accomplished by the presence of a level  16  properly affixed to elongated shear alignment tool  17 . With the shear machine being installed so that lower knife  8  is level, line identifying edge  7  can be set parallel to lower knife  8  by use of adjustment screws  4  and level  16 . 
         [0017]    Through this multifaceted tool, the operator is given several methods of alignment, all of which provide a massive improvement in accuracy with regard to the use of shears and other similar tools.

Technology Classification (CPC): 1