Power cylinder with internally mounted position indicator

In combination with a fluid pressure actuator of the piston and cylinder type comprising a cylinder and a piston assembly including a piston slidably mounted within said cylinder, a pair of end caps closing off either end of said cylinder to thereby define a fluid pressure chamber adjacent to each end cap on either side of said piston assembly, each end cap having an end face abutting against said piston in respective extreme positions of said piston in said cylinder;

• one of said fluid pressure chambers including a cavity formed between said piston and one of said end caps with said piston in abutment thereagainst, pressure port means for selectively pressurizing said one of said fluid pressure chambers, said piston assembly further including a piston rod affixed to said piston and extending through the other of said end caps;
• an indicator arrangement comprising:
• a bore formed into said piston assembly extending axially away from said one end cap, a cam rod having one end slidably fit into said bore formed into said piston assembly, said cam rod other end extending axially away from said piston assembly towards said one end cap;
• means axially fixing said cam rod element with respect to said cylinder whereby causing said one end of said cam rod to be reciprocated within said bore upon reciprocal stroking of said piston assembly in said cylinder;
• a plurality of radially converging plungers carried by said piston assembly and means biasing each of said plungers into engagement with a surface of said cam rod element causing rotation of said cam rod upon reciprocation of said piston assembly in said cylinder;
• rotary potentiometer means mounted within said cavity including a rotary wiper element;
• electrical connection means connected to said rotary potentiometer means and means providing a variable resistance in correspondence with the rotary position of said rotary wiper element;
• means drivingly connecting the other end of said cam rod and said rotary potentiometer wiper element producing corresponding rotation of said rotary wiper element upon rotation of said cam rod, whereby an electrical signal corresponding to the position of said piston assembly in said cylinder may be generated by said rotary potentiometer means.

In combination with a fluid pressure actuator of the piston and cylinder type comprising a cylinder and a piston assembly including a piston slidably mounted within said cylinder, a pair of end caps closing off either end of said cylinder to thereby define a fluid pressure chamber adjacent to each end cap on either side of said piston assembly, each end cap having an end face abutting against said piston in respective extreme positions of said piston in said cylinder;

• one of said fluid pressure chambers including a cavity formed between said piston and one of said end caps with said piston in abutment thereagainst, pressure port means for selectively pressurizing said one of said fluid pressure chambers, said piston assembly further including a piston rod affixed to said piston and extending through the other of said end caps;
• an indicator arrangement comprising:
• a bore formed into said piston assembly extending axially away from said one end cap, a cam rod having one end slidably fit into said bore formed into said piston assembly, said cam rod other end extending axially away from said piston assembly towards said one end cap;
• means axially fixing said cam rod element with respect to said cylinder whereby causing said one end of said cam rod to be reciprocated within said bore upon reciprocal stroking of said piston assembly in said cylinder;
• at least one camming element carried by said piston assembly in engagement with a surface of said cam rod element causing rotation of said cam rod upon reciprocation of said piston assembly in said cylinder;
• rotary potentiometer means mounted within said cavity including a rotary wiper element;
• electrical connection means connected to said rotary potentiometer means and means providing a variable resistance in correspondence with the rotary position of said rotary wiper element, said rotary potentiometer means including a drum mounted with its axis in alignment with said cam rod and wherein said cam rod extends through said drum and is received in a bore formed into said other of said end caps;
• means drivingly connecting the other end of said cam rod and said rotary potentiometer wiper element producing corresponding rotation of said rotary wiper element upon rotation of said cam rod, whereby an electrical signal corresponding to the position of said piston assembly in said cylinder may be generated by said rotary potentiometer means.