Variable work holding device for grinding gemstones

A work holding device for use with a planar abrading surface for grinding gemstones and industrial diamond tools comprising:

• (a) a body;
• (b) an extension means fixedly mounted on said body on a plane parallel to the plane of said abrading surface;
• (c) a rotatable dop holding means adapted for holding a stone bearing dop means, said rotatable dop holding means being moveably mounted on said fixed extension means;
• (d) motive power means for providing powered movement for said rotatable dop holding means;
• (e) means for transmitting said powered movement from said motive power means to said rotatable dop holding means for movement of said stone bearing dop means;
• and
• (f) said means for transmitting including a first linkage means connecting said motive power means to said rotatable dop holding means to provide reciprocal movement to said rotatable dop holding means and a second linkage means with one end of said second linkage means connected to said rotatable dop holding means and positioned eccentric to the axis of rotation of said rotatable dop holding means, the other end of said second linkage means connected to an abutment adjacent to said fixed extension means, said second linkage means imparting a semi-rotational movement to said rotatable dop holding means during the reciprocation caused by said first linkage means.

A work holding device for grinding gemstones and industrial diamonds comprising:

• a work holding means for holding a stone in contact with the cutting surface of a grinding skeif said work holding means comprising:
• slide bar means mounted on said work holding means for receiving a slideable spindle head,
• a slideable spindle head mounted on said slide bar for holding a rotatable spindle,
• spindle means mounted in said spindle head for rotating a dop,
• dop holding means mounted on said spindle means for holding a stone bearing dop,
• motive power means for powered operation of the device and for rotation of said spindle means,
• pulley means mounted on said spindle means for imparting rotary motion to said spindle means,
• eccentric pulley means mounted on said motive power means for use with a belt,
• belt means connecting said eccentric pulley means with said pulley means mounted on said spindle means for transmitting motion from said motive power means to said spindle means,
• linkage means, a first end of said linkage means mounted on said eccentric pulley means and a second end mounted on said spindle means for providing reciprocation to said spindle head and for maintaining a constant tension to said belt means,
• whereby when said motive power means rotates said eccentric pulley means said linkage means reciprocates said spindle head on said slide bar and said belt means rotates said pulley means mounted on said spindle means thereby rotating said dop holding means and a stone bearing dop and causing a stone to move across the the cutting surface of a grinding skeif in a reciprocating motion combined with a constant rotary motion for grinding said stone.