Apparatus and method for inductively measuring a representative variable or a variation in the circumference of a deformable object, and use of the apparatus on a shutter, a pressure probe or for inductance plethysmography
AssigneeCalyf
InventorFrancis COUR
Life of this patent
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Abstract
The measurement apparatus (50) comprises at least one hybrid elastic cable (52) wound around the deformable object (22), and a measurement unit (54) capable of measuring the inductance of a wire of the hybrid elastic cable (52) comprising a conductive material between two reference points (58).
Claims15
An apparatus for measuring a variable representative of a circumference or a variation of a circumference of a deformable object, wherein the apparatus comprises an inductance measurement unit, and
- at least one hybrid elastic cable coiled and arranged to form at least one winding around the deformable object, wherein the/each hybrid elastic cable comprises a wire of a first type and a wire of a second type,
- wherein, for the/each hybrid elastic cable, the wire of the first type has a degree of tenacity lower than that of the wire of the second type, wherein the wire of the second type has a degree of elasticity lower than that of the wire of the first type, wherein the wire of the second type comprises a conductive material,
- wherein, for the/each hybrid elastic cable, the wire of the second type is coiled helically around the wire of the first type when the hybrid elastic cable is at rest,
- wherein, for the/each hybrid elastic cable, the measurement unit comprises a pair of measuring terminals electrically connected to two reference points of the cable and is suited to measure the inductance of the wire of the second type of the cable between the two reference points of the cable,
- wherein the apparatus further comprises a calculator electrically connected to the measurement unit and configured to calculate the representative variable for the/each cable around the cable using the inductance of the wire of the second type of the cable being measured.
The apparatus according to claim 2, wherein the deformable object comprises a substantially circular cross-section at the level of the/each cable, and the calculator is configured to calculate the representative variable for a cable using a linear relationship between the inductance measured by the measuring unit and the representative variable.
A method for measuring a variable representative of a circumference or a variation of a circumference of a deformable object, wherein the method comprises the following steps:
- arranging at least one hybrid elastic cable that is coiled so as to form at least one turn around the deformable object, wherein the/each hybrid elastic cable comprises a wire of a first type and a wire of a second type,
- wherein, for the/each hybrid elastic cable the wire of the first type has a degree of tenacity lower than that of the wire of the second type, wherein the wire of the second type has a degree of elasticity lower than that of the wire of the first type, wherein the wire of the second type comprises a conductive material,
- wherein, for the/each hybrid elastic cable, the wire of the second type is coiled helically around the wire of the first type when the hybrid elastic cable is at rest,
- measuring the inductance of the wire of the second type of the cable between two reference points of the cable,
- for the/each cable, calculating the representative variable at the level of the cable using the inductance of the wire of the second type of the cable being measured.
Dependencies are inferred from the claim text.