Method and apparatus for grinding irregular surfaces

A portable grinder for grinding an elongated workpiece which comprises a base adapted to be secured on or adjacent the workpiece;

• a longitudinal track on said base;
• a carriage mounted on said longitudinal track;
• a follower mounted on the front end of said carriage and adapted to contact the surface of said workpiece;
• means for reciprocating said carriage along said longitudinal track;
• a grinder motor;
• a grinding wheel driven by said grinder motor and being so mounted that its grinding surface is rotating generally parallel to said longitudinal track when contacting the surface to be ground;
• means mounting said grinding wheel and motor on said carriage for movement toward and away from said track, said last named means including a trolley mounted on said carriage for transverse movement with respect to said base, a pair of transverse guide tracks on said carriage each having a horizontal rear section and a forward section positioned in a plane extending at an angle to the horizontal, and a shaft mounted on said trolley with its axis extending parallel to the longitudinal track for pivotally supporting said grinding wheel and motor;
• and means for causing reciprocating movement of said grinding wheel and motor toward and away from said track as the carriage moves along its track, said means for causing movement of said grinding wheel and motor includes means for reciprocating said trolley in said guide tracks.

A portable grinder for grinding an elongated workpiece which comprises a base adapted to be secured on or adjacent the workpiece;

• a longitudinal track on said base;
• a carriage having a pair of sidewalls mounted on said longitudinal track;
• a follower mounted on the front end of said carriage and adapted to contact the surface of said workpiece;
• means for reciprocating said carriage along said longitudinal track;
• a grinder motor;
• a grinding wheel driven by said grinder motor and having its axis transverse to said longitudinal track;
• means mounting said grinding wheel and motor on said carriage for movement toward and away from said track, said means mounting said grinding wheel and motor on said carriage including a trolley mounted on said carriage for transverse movement with respect to said base, a guide track holder slidable mounted on the outside of each side wall in opposed relationship for movement toward and away from said longitudinal track, a guide mounted in each holder, each guide including top and bottom horizontal rear sections and top and bottom front sections extending forwardly at an angle from the associated rear sections, means connecting said track holders, means for moving said track holders with respect to said carriage, a horizontal guide on the inside of each side wall in opposed relationship with the horizontal rear sections, and a shaft mounted on said trolley adjacent its rear end for pivotally supporting said grinding wheel and motor with its axis extending parallel to said longitudinal track;
• and means for causing reciprocating movement of said grinding wheel and motor toward and away from said track as the carriage moves along its track, said means for causing movement of said grinding wheel and motor includes means for reciprocating said trolley in said guide tracks.