Abstract:
An electro-mechanical arm for moving a part across the surface table of a rotary lapping machine to overcome to deficiencies inherent in normal lapping procedures.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    N/A  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    N/A  
         BACKGROUND OF THE INVENTION  
         [0003]    This invention pertains to an oscillating arm used as a guide for lapping to be used on planetary type, rotary lapping machines. Normally, such machines have two or three rings mounted to the table. At least one of these rings is used as a fixture to hold the part or parts while the table turns. The other ring is used to distribute the slurry, which is the lapping compound suspended in liquid, evenly over the table surface.  
           [0004]    Although this method has been used successfully, it does have some serious drawbacks. Parts cannot be larger than the ring. Only a certain portion of the table surface, which is made of cast iron, can be used. Due to the geometry of the ring, the part is held in place, being lapped only on one portion of the table surface. As the lapping process continues, heat is built up due to the friction of the part on the turning table surface. As the heat builds, the table surface undergoes minute changes. The table surface begins to distort and therefore causing the part or parts to be lapped unevenly. The friction between the table surface and the part causes harmonic vibrations. The harmonic vibrations cause patterns of distortions to form on the part along with visible feed lines.  
           [0005]    During production runs of a large number of parts, these problems become magnified. The table surface has to be constantly inspected to insure quality. Once the table surface fails inspection, the table surface must be reconditioned. This is costly in both time and money.  
         BRIEF SUMMARY OF THE INVENTION  
         [0006]    This invention is embodied as an electro-mechanical arm that oscillates across the table of a rotary lapping machine. By moving the part across the full radius of the table surface, the part will not be stationary on any one area. The will cause the table surface to wear evenly, regulate heat on the table surface, reduce downtime of the machine, reduce time reconditioning the table surface, extend the life of the table surface, and speed the lapping process. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is an isometric view of the basic embodiment of the invention.  
         [0008]    [0008]FIG. 2 is a side elevation of the invention  
         [0009]    [0009]FIG. 3 is a diagrammatical view of the invention as it would sit on the lapping machine and shows the direction of the motion transfer arm as the piston arm is extended.  
         [0010]    [0010]FIG. 4 is a diagrammatical view of the invention as it would sit on the lapping machine and shows the direction of the motion transfer arm as the piston arm is retracted. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0011]    The present invention has been made in order to correct the deficiencies of the present art and is described below.  
         [0012]    The present invention has been made in order to correct the deficiencies of present art.  
         [0013]    Shown in FIGS. 1 and 2, the invention is comprised of a electrically actuated piston  8  which is mounted to the lapping table by means of anchor coupling  3 , piston support column  2 , and piston support base plate  1 . The piston  8  movement is controlled by the means of a DC motor controller  9 . The power transfer arm  16  is attached to the piston  8  by the means of the piston coupling  11  and the pivot pin  25  and to the power shaft  19  a setscrew  27  or other means. Bearings  13  are used to facilitate the rotation of the power shaft  19 . The bearings  13  are set on the upper power shaft support  18  and the lower power shaft support  12  that are welded onto the power shaft support column  15 .  
         [0014]    The power control arm  21  is attached to the power shaft  19  by the adjustable shaft coupler  17 . The adjustable shaft coupler  17  can be moved to a higher or lower position by the use of setscrews  27 . The arm brace  20  is used to add rigidity to the power control arm  21 . The motion transfer arm  22  has a bearing  23  on the end to allow the part to move freely. The stroke control link  5  is also connected to the power transfer arm  15  via the pivot pin  25 . The other end of the stroke control link  5  is allowed to slide through a slot  24  that is milled in the guide brace  4  that is attached to the anchor coupling  3 .  
         [0015]    The operation of the present invention is as follows.  
         [0016]    The part to be lapped is set on the table surface. The power control arm is lowered by means of the adjustable shaft coupler  19  into the part. Multiple parts or parts that are not able to use the embodiment of the motion transfer arm  22  can be attached to the power control arm  21  by other fixtures. In this embodiment, a DC motor  9  is used to power the piston  8 , although hydraulic or pneumatic pistons may be used. A variable speed DC motor controller  9  is used to adjust the piston  8  speed.  
         [0017]    As the piston arm  28  pushes the power transfer arm  16  forward, the power transfer arm  16  rotates the power shaft  19  and moves the power control arm and therefore the part in one direction across the lapping table surface  31 . The distance the part moves in a direction is determined by the stroke control link  5  and two mechanical stops  7  which, are used to activate a toggle switch  10  that, when the limit is reached reverses the field of the DC motor  9  and causes the piston  8  to move in the opposite direction. The piston arm  28  then retracts the power transfer arm  15  and the stroke control link  5  and rotates the power shaft  19  in the opposite direction causing the power control arm  21  and therefore the part to move back to its original position until the first stop  7  is reached again, thus causing the process to repeat. The direction of movement of the motion control arm  21  in relation to the piston  8  is shown in FIGS. 3 and 4.  
         [0018]    This oscillation of the part across the table surface of the lapping machine keeps the part from staying too long on one area of the table surface and prevents heat streaks that can change the characteristics of the surface. It also allows parts that are too large for the ring system to be lapped. Since the part is not stationary on one part of the table, the surface feet rate is constantly changing allowing the lapping process time to be decreased.