US 4,223,300 AGranted

Electro mechanical position indicator using relatively moveable coils

AssigneeAGA Aktiebolag

InventorKlas R. Wiklund

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Abstract

An electromechanical positioner indicator is provided which comprises first and second relatively movable parts, the first part including two oppositely facing surfaces which are everywhere equidistant and the second part including two surfaces which are everywhere equidistant and which are everywhere equispaced from and lie, closely adjacent to respective ones of the two surfaces of the first part. A first coil, preferably in printed circuit form, is secured to the first part and sensing coils, also preferably in printed circuit form, are secured to each of the two surfaces of the second part. The inductive coupling between the coils is dependent on the relative positions of the parts and thus the output of the sensing coils provides an indication of position. In one embodiment, the surfaces in question are formed by cylinders and in another, the first part is a disc and the main coil comprises an annulus. Particular coil and coil conductor shapes are also disclosed.

Claims28

Dependent claims

Electromechanical apparatus comprising first and second relatively rotatable parts, said first part including two oppositely facing parallel surfaces and said second part including two parallel surfaces each of which extends parallel to, and lies closely adjacent to, a respective one of said two surfaces of the first part, at least one said surface of the first part having secured thereto a first coil and the said two surfaces of the second part each having secured thereto at least one further coil and means for mounting said first and second parts for relative rotational movement so as to cause said further coils secured to the two surfaces of said second part to move along a predetermined path relative to said first coil, the inductive coupling between each said further coil and said first coil being dependent on the relative rotational position of said parts and said coils providing more than one electrical cycle per complete mechanical rotation of said relatively rotatable parts, an alternating current voltage being supplied to said first coil and coupled to said further coils, said apparatus further comprising electronic processing means for producing an output representative of said relative rotational position, said processing means being connected to said further coils and comprising electronic storage means having a plurality of storage locations which are individually addressable in response to addressing signals, means for deriving said addressing signals including counter means for counting said electrical cycles so as to identify the relevant sector of the mechanical rotation of said relatively rotatable parts, the said addressing signals being supplied to an address input of said storage means and said storage means further acting to store correction signals corresponding to respective measured values representative or angular positions in the relevant sectors of said mechanical rotation, and correction means for receiving said correction signals from said storage means and for correcting said measured values in accordance with said correction signals, said correction means providing a said output representing each measured value thus corrected.

Electromechanical apparatus comprising first and second relatively rotatable parts, said first part comprising a cylinder including two oppositely facing cylindrical surfaces each of which is equispaced from, and lies closely adjacent to, a respective one of said two cylindrical surfaces of the first part, at least one said surface of the first part having secured thereto a first coil and the said two surfaces of the second part each having secured thereto at least one further coil, and means for mounting said first and second parts for relative rotational movement so as to cause said further coils secured to the two surfaces of said second part to move along a predetermined path relative to said first coil, the inductive coupling between each said further coil and said first coil being dependent on the relative position of said parts and said coils providing at least two electrical cycles per complete mechanical rotation of said relatively rotatable parts, an alternating current voltage being supplied to said first coil and said apparatus further comprising electronic processing means for producing an output representative of said relative position, said processing means being connected to said further coils and comprising electronic storage means having a plurality of storage locations which are individually addressable in response to addressing signals, means for deriving said addressing signals including counter means for counting said number of electrical cycles so as to identify the relevant sector and the mechanical rotation of said relatively rotatable parts the said addressing signals being supplied to an address input of said storage means and said storage means storing correction signals corresponding to respective measured values representative of angular positions in said relevant sectors of said mechanical rotation and correction means for receiving said correction signals from said storage means and for correcting said measured values in accordance with said correction signals, said correction means providing a said output representing each measured value thus corrected.

Dependencies are inferred from the claim text.