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AssigneeLucas Industries Limited
InventorsAlan Goodwin, Malcolm Brearley
Estimating the term…
An inductive displacement transducer is described in which the magnitude of the phase difference between A.C. current and voltage in a coil is dependent upon the axial displacement of a monitored object. The phase difference depends upon the axial position relative to the coil of a short-circuit turn which moves with the monitored object. A magnetic flux concentrator, which may be combined with the short circuit turn, enhances the flux linkage between the short-circuit turn and the coil. In order to sense the height of a vehicle suspension strut, the coil is mounted on a plastics dirt shield, the short-circuit turn is provided by a sleeve plated with an electrically conductive metal and secured to the strut cylinder. Various circuits are described for monitoring the height signals produced by the different suspension struts of a vehicle.
A displacement measuring transducer for measuring the displacement of a monitored object comprising a coil, an A.C. source connected to said coil, a core assembly fixedly associated with said monitored object and which is axially movable relative to said coil, said core assembly comprising a short-circuit turn and a magnetic flux concentrator arranged to enhance the flux linkage between said short-circuit turn and said coil, and measuring means connected to said coil for measuring changes in the phase relationship between the voltage and current in said coil, said core assembly being so arranged that on increasing penetration of said core assembly into said coil the inductance of said coil increases and the reflected shunt resistance across said coil decreases to provide said changes in said phase relationship.
A system for measuring the displacements of a plurality of monitored objects, comprising a respective core assembly fixedly associated with each of said monitored objects, and a respective coil, each core assembly comprising a respective short-circuit turn and a respective magnetic flux concentrator arranged to enhance the flux linkage between each said coil and the respective short-circuit turn each said core assembly being axially movable relative to the respective coil, and each said core assembly being so arranged that on increasing penetration of said core assembly into the respective coil the inductance of said coil increases and the reflected shunt resistance across said coil decreases to provide changes in the phase relationship between the voltage and current in said coil, a series electrical circuit comprising said coils and series electrical connections between said coils, an A.C. source connected in series with said series electrical circuit, and measuring means connected to each said coil for measuring changes in said phase relationship in each coil.
A vehicle suspension assembly comprising first attachment means for connection to a sprung member of a vehicle, second attachment means for connection to an un-sprung member of the vehicle, a first part associated with said first attachment means, a second part associated with said second attachment means, said first and second parts being movable relative to each other on expansion and contraction of the assembly, a coil mounted on one of said parts, and a core assembly associated with the other of said parts, whereby said core assembly moves axially relative to said coil on expansion and contraction of the assembly, an A.C. source connected to said coil, said core assembly comprising a short-circuit turn and a magnetic flux concentrator arranged to enhance the flux linkage between said short-circuit turn and said coil, and measuring means connected to said coil for measuring changes in the phase relationship between the voltage and current in said coil, said core assembly being so arranged that on increasing penetration of said core assembly into said coil the inductance of said coil increases and the reflected shunt resistance across said coil decreases to provide said changes in said phase relationship.
Dependencies are inferred from the claim text.