EP0182085A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Position and speed sensors
Assignee: Dr Johannes Heidenhain GmbH
•
Filing: 1985-10-14
•
Granted: —
•
Expires: 2005-10-14
Abstract
Abstract In a sensor having a drive winding (121) for establishing a forward field, an electrically conductive screen (123) is displaceable relative to a sense winding (122). In the presence of the drive field, eddy currents are generated in the screen to establish a counter-field opposing the forward field, so that the sense winding is shaded by the screen to a varying extent during relative displacement of screen and sense winding and the voltage induced in the sense winding is accordingly correspondingly varied. Application of a high frequency input to the drive winding (121) results in a modulated output from the sense winding (122) which may be demodulated to provide a signal indicative of screen position relative to sense winding. The position signal may be further processed to provide a speed signal. The sensor may assume a multiplicity of linear or planar, rotational and axial or solenoidal configurations.
Inventors
- 👤 Francis Dr. Mcmullin
- 👤 John V. Byrne
- 👤 Aengus Murray
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 18:39
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/42; G01D; G01D5/00; G01D5/12; G01D5/14; G01D5/20; G01D5/204; G01D5/2053; G01D2205/00; G01D2205/70; G01D2205/77
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
117 words
A sensor comprising a drive or exciting winding (121) for establishing a forward or drive field, at least one secondary or sense winding (122) in which a voltage may be induced in the presence of a said forward or drive field, and at least one conductive screen (123) within which eddy currents are generated in the presence of a said forward or drive field to establish a counter-field opposing said forward field, said screen (123) and secondary winding (122) being displaceable relative to one another within said drive field so that said secondary winding (122) may be shaded by said screen (123) to a varying extent to thereby vary the voltage induced in said secondary winding (122).
Claim 2
Dependent Claim
117 words
A sensor comprising a drive or exciting winding (121) for establishing a forward or drive field, at least one secondary or sense winding (122) in which a voltage may be induced in the presence of a said forward or drive field, and at least one conductive screen (123) within which eddy currents are generated in the presence of a said forward or drive field to establish a counter-field opposing said forward field, said screen (123) and secondary winding (122) being displaceable relative to one another within said drive field so that said secondary winding (122) may be shaded by said screen (123) to a varying extent to thereby vary the voltage induced in said secondary winding (122).
Claim 3
Dependent Claim
56 words
A sensor according to claim 1, comprising a plurality of secondary or sense windings (201, 202), each said winding (201) being oriented relative to the other (202) or others of said windings so each said winding provides a varying voltage output substantially indicative of screen position in a respective particular direction (X, Y) of screen displacement.
Claim 4
Dependent Claim
26 words
A sensor according to claim 2, having three secondary or sense windings (215a, 215b, 215c) disposed for the detection of three-dimensional (X, Y, Z) screen displacement.
Claim 5
Dependent Claim
127 words
A sensor according to claim 1, wherein said relative displacement of said screen (7, 126) and said secondary or sense winding (6, 125) is limited to substantially a single direction of displacement, said screen (7, 126) has a surface region which is substantially parallel to a notional surface defined by said secondary or sense winding (6, 125), said surface region is a sector of a cylindrical surface, and said secondary or sense winding (6, 125) is disposed about the periphery of a notional cylinder substantially concentric with said cylindrical surface region sector, said screen (7, 126) and said secondary or sense winding (6, 125) being relatively displaceable in an axial or a circumferential direction about the substantially common axis of said cylindrical surface and said notional cylinder.
Claim 6
Dependent Claim
108 words
A sensor according to claim 4, comprising a further secondary or sense winding (144), the progressive shading of which during said relative displacement of said screen (145) and said first secondary or sense winding (143) proceeds in a manner substantially identical with the progressive shading of said first secondary or sense winding (143) during said relative displacement, wherein said further secondary or sense winding (144) is disposed relative to said first secondary or sense winding (143) so that the progressive shading of said further secondary or sense winding (144) during said relative displacement is spaced apart in time from that of said first secondary or sense winding (143).
Claim 7
Dependent Claim
89 words
A sensor according to any of claims 2 to 5, wherein the or each said secondary or sense winding (130) has a phase loop or coil (130a) wound in one electrical sense and an anti-phase loop or coil (130b) wound in the opposite electrical sense, so that in the presence of a said forward or drive field, the voltage induced in the anti-phase coil (130b) in the absence of said screen (131) is substantially equal in magnitude but opposite in polarity to that induced in the phase coil, (130a).
Claim 8
Dependent Claim
58 words
A sensor according to any of claims 2 to 6, wherein the or each said secondary or sense winding (142) has a multiplicity of coils or loops extending in said direction of relative displacement and each successive coil or loop in said direction is wound in the opposite electrical sense to the or each adjacent coil or loop.
Claim 9
Dependent Claim
76 words
A sensor according to any of claims 6 to 7, wherein said screen and/or the or each said secondary or sense winding are configured so that successive incremental regions (dA) of the or each said secondary or sense winding (122) shaded by incremental advance of said screen (123) during relative displacement of said screen (123) and said secondary or sense winding (122) vary in magnitude from point to point along the path of said relative displacement.
Claim 10
Dependent Claim
91 words
A sensor according to any of claims 2 to 8, wherein said screen or screens (3a, 3b) and said secondary or sense winding or windings (2) are in close juxtaposition during said relative displacement, spaced apart by an airgap, and the or each said screen (3a, 3b) has respective screen portions (3a, 3b) disposed one to each side of said secondary or sense winding or windings (2), or respective portions (2a, 2b) of said winding or windings (2a, 2b) are disposed one to each side of said screen or screens (3).
Claim 11
Dependent Claim
101 words
A sensing system comprising a sensor according to any preceding claim, means (216) for applying an alternating voltage to said drive winding, means (218) for demodulating the voltage output or outputs of said secondary or sense winding or windings to provide a signal indicative of the relative disposition of said screen or screens and said secondary or sense winding or windings, and/or means (220) for transforming a voltage output of said secondary or sense winding or windings into a signal indicative of the speed of said relative displacement of said screen or screens and said secondary or sense winding or windings.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.