Robotic control apparatus

Claim 1

In a robotic apparatus or fluid actuators utilizing a ring of resilient flexible magnetic material formed of rubbery material having magnetic particles therein carried by a piston within a cylinder for signaling a at least one control means as to the position of the piston and the apparatus operated thereby, means mounting said ring of magnetic material on said piston comprising: an annular receptacle carried in said piston, said ring of magnetic material being separated and having opposed ends facilitating placement of the ring within said annular receptacle extending about the piston, means within said annular receptacle confining said ring and securing same to said piston and out of contact with a wall of said cylinder, said piston being of unitary integral construction and is connected to means extending outside the cylinder for performing a function, and sealing means carried by said piston preventing the passage of an operating fluid between a piston wall and said cylinder wall.