Fluidic repeater

Fluidic repeater comprising:

• a transmitter, a responder, a single line for transmitting pressure signals between said transmitter and responder, and fluid supply means including a source of pressure fluid for causing a pressure fluid to flow through said line,
• said transmitter including a variable flow obstructor connected in the aforementioned pressure signal transmitting line between one end thereof and said responder to create a variable pressure difference upstream and downstream of the obstructor and thereby vary the pressure in the portion of said line between said obstructor and said responder,
• said transmitter further including operator means connected to the flow obstructor for changing the position of the obstructor between a first position partly blocking said fluid flow and a second position blocking said fluid flow to a lesser extent and a continuous range of intermediate positions of differing degrees of blocking said fluid flow between the blocking in said first and second positions and maintaining the obstructor in any desired one of said first, second and all intermediate positions,
• said responder including a cylinder having a piston movable axially therein, said cylinder having a peripheral surface and said piston having a periphery adapted to slide axially within said peripheral surface over a range of axial motion, said piston having two transverse portions athwart the axis of the piston adapted to receive fluid pressure, said cylinder having two transverse portions athwart the axis of the cylinder,
• said transverse portions of the cylinder being farther apart than said transverse portions of the piston leaving spaces between the transverse portions at each end of said periphery of the piston and the transverse portions at the corresponding end of said peripheral surface of the cylinder when said piston is positioned between the ends of said range of axial motion,
• the aforementioned pressure signal transmitting line connecting at its other end to the responder cylinder to communicate with one of said spaces,
• opposition means communicating with the other of said spaces creating an opposing force thereon independent of the position of the transmitter operating means, and
• feedback means including a flow passage communicating with the other of said spaces to vary the pressure therein by connecting the last said space to reservoir of fluid at lower pressure than said line without passing through said pressure signal transmitting line, a variable flow restrictor in said flow passage, and means connecting said variable flow restrictor to said responder to cause displacement of said flow restrictor in an amount dependent upon the amount of displacement of said responder piston and independent of the rate of said piston's displacement and of the length of time said piston's displacement persists,
• said cylinder including an aperture in one of said transverse portions thereof, said piston having a piston rod extending through said aperture adapted for connection to a load,
• said feedback means functioning to bring said piston to rest in different positions over a continuous range of positions corresponding to said continuous range of positions of said operator means of said transmitter to thereby place said piston rod and any load attached thereto in any desired position over a continuous range of positions,
• said single line extending from said one of said spaces through said obstructor to said reservoir of fluid at lower pressure than said line,
• said fluid supply means comprising a branch line having a second flow restrictor therein extending from said single line between said one of said spaces and said obstructor through said second flow restrictor to said source of pressure fluid, whereby fluid from said source can flow through said second flow restrictor and branch line to said single line and thence through a portion of said single line and said variable flow obstructor of the transmitter to said reservoir, by-passing said one of said spaces.