Suction pad, rotation--stop and guide mechanism for the same

A rotation-stop and guide mechanism for a suction pad, comprising:

• a shaft, coupled at one end thereof to a suction pad and coupled at the other end thereof to a tube for communicating with a vacuum source, having a through hole defined therein for allowing communication between said suction pad and said tube;
• a cylindrical member externally fitted over said shaft and displaceable along said shaft;
• a resilient member interposed between said suction pad and the cylindrical member;
• and
• rotation-stop means for stopping rotation of said cylindrical member with respect to said shaft, comprising
• raised lines provided on either the outer wall surface of said shaft or the inner wall surface of the cylinder member, extending along the axis of said shaft, angularly spaced by a predetermined angle, and
• rolling members arranged between said cylindrical member and said shaft, said rolling members working in cooperation with said raised lines to stop the rotation of said cylindrical member against said shaft, and rolling upon linear displacement of said cylindrical member along said shaft.