Motion translating mechanism for toothbrush power handle

Claim 1

IN A MOTORIZED HANDLE FOR DRIVING A TOOTHBRUSH, A CASING HAVING A LONGITUDINAL AXIS, A HOLDING MEMBER POSITIONED WITHIN ONE END OF SAID CASING, SAID MEMBER HAVING ONE END ADAPTED TO RECEIVE A TOOTHBRUSH, A MOTOR POSITIONED IN SAID CASING, ROTARY MEANS DRIVEN BY SAID MOTOR, A PIN EXTENDING IN A DIRECTION SUBSTANTIALLY PERPENDICULAR TO SAID CASING LONGITUDINAL AXIS, SAID PIN BEING MOUNTED ON SAID ROTARY MEANS TO BE MOVED IN A CIRCULAR PATH BY SAID MOTOR IN A DIRECTION TRANSVERSE TO THE PIN AXIS, AN ELONGATED SLOT EXTENDING THROUGH THE OPPOSITE END OF SAID HOLDING MEMBER HAVING A MAJOR AND A MINOR AXIS, THE MAJOR AXIS OF THE SLOT BEING GREATER THAN THE DIAMETER OF THE PATH MOVED BY SAID PIN, THE MINOR AXIS OF THE SLOT BEING LESS THAN THE PATH DIAMETER BUT GREATER THAN THE PIN DIAMETER, SAID PIN AND SLOT BEING ARRANGED SO THAT THE PIN EXTENDS THROUGH THE SLOT IN A DIRECTION PERPENDICULAR TO THE LONGITUDINAL AXIS OF THE SLOT WHEREBY CIRCULAR MOVEMENT OF SAID PIN RECIPROCATES SAID HOLDING MEMBER, GUIDE MEANS PERMITTING ONLY STRAIGHT LINE RECIPROCATION OF SAID MEMBER IN A DIRECTION PARALLEL TO THE CASING LONGITUDINAL AXIS, THE MINOR AXIS OF THE SLOT BEING LOCATED WITH RESPECT TO SAID HOLDER DIRECTION OF TRAVEL AT AN ACUTE ANGLE WHOSE TANGENT IS APPROXIMATELY EQUAL TO THE COEFFICIENT OF FRICTION BETWEEN SAID PIN AND SAID SLOT, THE ROTATIONAL DIRECTION OF SAID PIN BEING THE SAME AS THE ANGULAR DIRECTION SAID ANGLE EXTENDS FROM THE HOLDER DIRECTION OF TRAVEL.