Self-castering glass cutter and compensating bi-directional head

Apparatus for scoring sheet glass, comprising a support body adapted for relative movement in a plane generally parallel to the glass to be scored, piston means in said support body and adapted for limited reciprocating movement on a line oriented perpendicular to said plane, biasing means to urge the piston means toward the glass, and glass engaging rollers on said piston means, glass scoring wheel support means reciprocably mounted in said piston means for limited movement on the same line of action as that of said piston means, biasing means acting between said piston means and said wheel support means, said glass scoring wheel support means including a holder means rotatable on said line of action and defining a downwardly open slot with spaced inner stop surface segments, a pendulum member pivotally supported in said slot on an axis intersecting said line of action at right angles and adapted for pendulous movement in said slot between limit positions determined by abutment with said stop surfaces, a glass scoring wheel provided in said pendulum member for rotation on an axis which is spaced rearwardly of said line of action to provide a castering action in one and an opposite direction, as a result of rolling contact between said wheel and the glass.