Centering device

A centering device comprising:

• (a) a centering pointer having:
• a cylindrical, hollow metallic holder having a longitudinal center axis and two ends and being adapted to be coaxially detachably mounted onto the spindle of a manufacturing machine;
• a metallic needle member slidably held within said holder and having a pointed lower end extending out of one end of said holder and an upper end disposed within said holder, and a stopper adapted to limit the axial movement of said needle member with respect to said holder, said needle member being in sliding contact with an inner wall of said holder;
• a spring means to urge said needle member towards the said lower end of said holder;
• a probe member coaxially slidably held within said holder to correspond with the upper end of said needle member, said probe member being electrically conductive and electrically insulated from said holder;
• a resilient, metallic contact member adapted to fricitonally restrict the movement of said probe member;
• an elastic cap for covering the upper end of said holder,
• a visual indicator means comprising an indicator lamp, a dry battery a switch and an electric cord connecting said switch and said resilient contact member so arranged that with said switch turned on said indicator lamp is caused to be lit when the upper end of said needle member comes into contact with said probe member;
• and
• (b) a truncated cylindrical centering block provided with a cylindrical surface having a center axis, and an L-shaped cutaway having two planar surfaces forming a 90 degree angle therebetween, at least one of said surface passing through said center axis;
• said centering block adapted to be mounted on an article having a vertical planar surface with one surface abutting said vertical planar surface of said article to be aligned with the center axis of said centering pointer, said alignment being attained by causing said needle member of said centering pointer to move axially by moving said centering block with said article in a direction perpendicular to the center axis of said centering pointer so that said lower end of said needle member contacts and moves along said cylindrical surface with upward movement of said needle member causing said probe member to move to and remain at a position where said needle member comes into contact therewith and moves apart therefrom to activate said visual indicator means which thereby indicates that the center axis of said centering pointer has been aligned with the center axis of said centering block.