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US 9,341,266 B1Granted
Position sensing hydraulic cylinder
AssigneeTexas Hydraulics, Inc.
InventorReed Vivatson
Life of this patent
Estimating the term…
Abstract
A hydraulic cylinder has an internal shaft that rotates in response to extension or contraction of an output rod. A magnet is affixed to the shaft, the position of which is detected by a sensor internal to the hydraulic cylinder for determining the position of the output rod.
Claims20
A hydraulic cylinder comprising:
- a barrel with an end cap on a first end thereof defining a first working end of the hydraulic cylinder;
- a rod that extends from a second end of the barrel in response to hydraulic pressure applied to an attached piston within the barrel, the output rod defining a second working end of the hydraulic cylinder;
- a helical shaft having a magnet on a first end thereof and extending into the rod on a second end thereof;
- and
- a bushing in a fixed relationship with respect to the rod;
- a magnetic sensor for sensing the linear position of the piston, contained inside the end cap of the hydraulic cylinder and mechanically isolated from the rod and the hydraulic pressure applied to the piston;
- wherein the first end of the helical shaft is affixed to the end cap with the magnet within sensing proximity of the magnetic sensor, which senses the rotational position of the helical shaft relative to the end cap;
- and
- wherein the bushing mates with the helical shaft in a sliding relationship such that the helical shaft is rotated in response to extension or contraction of the rod from the barrel.
6 more elements
A hydraulic cylinder comprising:
- first and second working ends anchored to a machine frame and a load, respectively, with an output rod therebetween having a fixed position relative to the second working end;
- a bushing mated to the output rod such that the bushing extends and contracts with the second working end;
- an internal shaft affixed to the first working end such that the internal shaft extends and contracts with the first working end;
- and
- a sensor situated inside an end cap that defines the first working end, the sensor detecting a degree of rotation of the internal shaft in order to determine the linear position of the piston without a mechanical linkage to the internal shaft;
- wherein the bushing has an internal contour that is complementary to an outer contour of the internal shaft such that the internal shaft rotates a predetermined amount relative to a predetermined amount of extension or contraction of the first and second working ends.
3 more elements
A hydraulic cylinder comprising:
- a barrel having an end cap on a first end thereof and having a gland on a second end thereof;
- an output rod in a sliding engagement with the gland and having a working end and an opposite end attached to a hydraulic piston within the barrel;
- a housing retained by the end cap, the housing containing a first end of a rotatable internal shaft, the shaft providing at least one magnet affixed thereto;
- a sensor retained by the end cap for sensing the position of the magnet;
- and
- a guide affixed to the housing and providing a longitudinal channel within the output rod;
- wherein a transverse circumferential groove is defined with respect to the output rod that imparts extension and contraction of the output rod to a tang affixed to a bushing, the tang travelling within the longitudinal channel and being restrained from rotational movement within the transverse circumferential groove;
- and
- wherein an internal contour of the tang cooperates with an external contour of the internal shaft such that extension or contraction of the bushing relative to the end cap imparts a predetermined rotation to the internal shaft that may be read magnetically by the sensor.
6 more elements
Dependencies are inferred from the claim text.