Travel feedback system
AssigneeFisher Controls International LLC
InventorMichel K. Lovell
Life of this patent
Estimating the term…
Abstract
A linear feedback travel assembly includes a first tube end, a second tube end, and a longitudinal axis. A drive rod includes a first end and a second end, and a cam includes a first end, a second end, and a wall defining a bore, a first slot, and a second slot. The cam is movable along, and rotatable about, the longitudinal axis. A first pin is movably disposed in the first slot of the cam and is fixed relative to the first tube end. A second pin is movably disposed in the second slot of the cam and connects the drive rod to the cam. When the cam moves along the longitudinal axis, the first pin moves within the first slot and rotates the cam about the longitudinal axis. The second pin rotates the drive rod as the second pin moves within the second slot of the cam.
Claims20
A linear feedback travel assembly comprising:
- a first tube end, a second tube end opposite the first tube end, and a longitudinal axis;
- a drive rod including a first end disposed proximal to the first tube end, and a second end opposite the first end;
- a cam including a first end, a second end opposite the first end and disposed within the second tube end, and a wall defining a bore, a first slot, and a second slot, the bore sized to slidably receive the drive rod, the cam being movable along the longitudinal axis and rotatable about the longitudinal axis when the second tube end receives a linear input;
- a first pin movably disposed in the first slot of the cam, the first pin fixed relative to the first tube end;
- a second pin movably disposed in the second slot of the cam and connecting the second end of the drive rod to the cam;
- and
- wherein when the cam linearly moves along the longitudinal axis, the first pin moves within the first slot of the cam and rotates the cam about the longitudinal axis, the second pin rotates the drive rod as the second pin moves within the second slot of the cam.
A linear travel feedback system comprising:
- a transducer having a first end and a second end opposite the first end, the transducer including a drive rod and a cam coaxially aligned relative to a longitudinal axis of the transducer, the drive rod including a first end proximal to the first end of the transducer and a second end opposite the first end, and the cam including a first end and a second end opposite the first end, wherein the second end of the cam is coupled to the second end of the transducer;
- a first mounting assembly arranged to couple the first end of the transducer to an actuator housing;
- a second mounting assembly arranged to couple the second end of the transducer to a stem so that the second mounting assembly is movable with the stem;
- wherein the transducer is movable between a compressed position, in which the second end of the drive rod is proximally located relative to the second end of the cam, and an extended position, in which the second end of the drive rod is spaced from the second end of the cam.
A method of determining linear travel of an actuator, the method comprising:
- mounting a first end of a transducer to an actuator housing of an actuator assembly, the transducer including a cam, a drive rod, a first pin coupled to a spiral slot in the cam, and a second pin coupling the drive rod to a linear slot of the cam, the drive rod and cam aligned with a longitudinal axis of the transducer;
- mounting a second end, opposite the first end, of the transducer to a stem connected to the actuator assembly, the stem movable relative to the actuator housing in a linear direction, the transducer movable with the stem between a compressed configuration and an extended configuration along the longitudinal axis;
- coupling a digital valve controller to the transducer;
- receiving, via the second end of the transducer, a linear input from the stem when the stem moves a distance in the linear direction, the second end of the transducer coupled to the cam;
- transferring the linear input from the stem to the cam, the cam axially movable along the longitudinal axis;
- converting the linear input of the stem to a rotational output of the cam, the first pin rotating the cam about the longitudinal axis when the cam moves linearly along the longitudinal axis;
- receiving, via the drive rod, the rotational output of the cam;
- converting the rotational output of the cam to a rotational output of the drive rod, the second pin rotating the drive rod about the longitudinal axis when the second pin moves relative to the linear slot of the cam;
- receiving, via the digital valve controller, the rotational output of the drive rod;
- and
- measuring the distance of the stem using the rotational output of the drive rod.
Dependencies are inferred from the claim text.