Air core gauge with zero pointer return related application

Claim 2

An air core gauge for driving a mechanical indicator proportionally to the value of a remote condition, comprising: at least two angularly related coils, input signal means responsive to the remote condition for varying the current flow through the coils and the resulting mmfs to drive a mechanical indicator from a zero position to a maximum value position, fixed force means for continuously biasing the indicator toward its zero position continuously generally in force and directional alignment with the mmf of one of the coils, an unregulated supply voltage for the coils that varies the current in the coils, and fixed voltage drop means in series with said one coil so the coil mmfs and the fixed force means acting on the indicator remain balanced with changes in supply voltage, said fixed force means biasing the indicator toward its zero position with supply voltage applied to the coils.

Claim 3

An air core gauge for driving a mechanical indicator proportionally to the value of a remote condition, comprising: at least two angularly related coils, input signal means responsive to the remote condition for varying the current flow through the coils and the resulting mmfs to drive a mechanical indicator from a zero position to a maximum value position, fixed force means for continuously biasing the indicator toward its zero position, generally in force and directional alignment with the mmf of one of the coils, a variable supply voltage for the coils that varies the current in the coils, and fixed voltage drop means in series with said one coil so that changes in supply voltage cause a greater change in flux in said one coil than the other coil, said fixed force means biasing the indicator toward its zero position with supply voltage applied to the coils.

Claim 4

An air core gauge for driving a mechanical indicator proportionally to the value of a remote condition, comprising: at least two angularly related coils, input signal means responsive to the remote condition for varying the current flow through the coils and the resulting mmfs to drive a mechanical indicator from a zero position to a maximum value position, fixed force means for continuously biasing the indicator toward its zero position, generally in force and directional alignment with the mmf of one of the coils, a variable supply voltage for the coils that varies the current in the coils, and fixed voltage drop means in series with said one coil so that changes in supply voltage cause a greater change in flux in said one coil than the other coil, said fixed force means biasing the indicator toward its zero position with supply voltage applied to the coils.

Claim 5

An air core gauge as defined in claim 1, wherein said coils include orthogonally related first and second coils and a third coil aligned with the first coil and producing an mmf opposite the mmf produced by the first coil, said first and second coils producing mmfs that both vary proportionally with the input signal means and said third coil producing an mmf independent of the input signal means, said fixed force means acting in the same direction as the mmf produced by the third coil, said fixed voltage drop means being in series with the third coil so the mmf produced by the third coil varies more with supply voltage change than the mmfs produced by the first and second coils to balance forces acting on the indicator so the direction of the resultant mmf of the three coils and the fixed force means is unaffected by changes in supply voltage.

Claim 6

An air core gauge as defined in claim 1, wherein the indicator is a rotary pointer having a magnetic rotor connected thereto, said fixed force means being a permanent magnet adjacent and acting on the rotor to bias the pointer continuously toward its zero position.

Claim 7

An air core gauge as defined in claim 1, wherein the fixed voltage means is a zener diode in series with said one coil.

Claim 8

An air core gauge as defined in claim 3, wherein the first and second coils are in series and the third coil is parallel to the first and second coils, said voltage drop means being a zener diode in series with the third coil.

Claim 9

An air core gauge for driving an indicator pointer to an angular position proportionally to the value of a sensed condition, comprising: first and second orthogonally related coils producing orthogonal mmfs acting on the pointer that vary in magnitude with the sensed condition, a third coil positioned to produce an mmf acting on the pointer aligned with and opposing the mmf of the first coil, said third coil being unresponsive to variations in the sensed condition, an unregulated supply voltage for the first, second and third coils, whereby changes in supply voltage produce changes in current in all three coils, means for biasing the pointer toward a minimum indicating position including a constant return force acting on the pointer that is constant with changes in supply voltage, and a fixed voltage drop device in series with the third coil to offset the effect of the constant return force acting on the pointer.

Claim 10

An air core gauge for driving an indicator pointer to an angular position proportionally to the value of a sensed condition, comprising: first and second orthogonally related coils producing orthogonal mmfs acting on the pointer that vary in magnitude with the sensed condition, a third coil positioned to produce an mmf acting on the pointer aligned with and opposing the mmf of the first coil, said third coil being unresponsive to variations in the sensed condition, an unregulated supply voltage for the first, second and third coils, whereby changes in supply voltage produce changes in current in all three coils, means for biasing the pointer toward a minimum indicating position including a constant return force acting on the pointer that is constant with changes in supply voltage, and a fixed voltage drop device in series with the third coil to offset the effect of the constant return force acting on the pointer.

Claim 11

An air core gauge as defined in claim 7, wherein the means for biasing the pointer toward a minimum indicating position includes a rotor magnet connected to the pointer and a stationary magnet adjacent the permanent magnet with its preferred flux lines aligned with the minimum indicating position of the pointer.

Claim 12

An air core gauge as defined in claim 7, wherein the fixed voltage drop device is a zener diode.

Claim 13

An air core gauge as defined in claim 7, including a temperature compensating resistor in series with the third coil to offset the effect of temperature changes on the first and second coils.

Claim 14

An air core gauge for driving an indicator pointer to an angular position proportionally to the value of a sensed condition, comprising: first and second orthogonally related coils producing orthogonal mmfs acting on the pointer that vary in magnitude with the sensed condition, a third coil positioned to produce an mmf acting on the pointer aligned with and opposing the mmf of the first coil, said third coil being unresponsive to variations in the sensed condition, an unregulated supply voltage for the first, second and third coils whereby changes in supply voltage produce changes in current in all three coils, a magnetized rotor fixed with respect to the pointer, a stationary magnet adjacent the pointer rotor positioned so that its preferred flux lines bias the rotor and pointer toward a pointer minimum indicating position, and a zener diode in series with the third coil to offset the biasing effect of the stationary magnet acting on the rotor, said zener diode having a fixed voltage drop according to the equation: ##EQU4## where V z =zener diode voltage, V b =battery voltage, HC=third coil mmf, and H m =stationary magnet mmf.

Claim 15

An air core gauge for driving an indicator pointer to an angular position proportionally to the value of a sensed condition, comprising: first and second orthogonally related coils producing orthogonal mmfs acting on the pointer that vary in magnitude with the sensed condition, a third coil positioned to produce an mmf acting on the pointer aligned with and opposing the mmf of the first coil, said third coil being unresponsive to variations in the sensed condition, an unregulated supply voltage for the first, second and third coils whereby changes in supply voltage produce changes in current in all three coils, a magnetized rotor fixed with respect to the pointer, a stationary magnet adjacent the pointer rotor positioned so that its preferred flux lines bias the rotor and pointer toward a pointer minimum indicating position, and a zener diode in series with the third coil to offset the biasing effect of the stationary magnet acting on the rotor, said zener diode having a fixed voltage drop according to the equation: ##EQU4## where V z =zener diode voltage, V b =battery voltage, HC=third coil mmf, and H m =stationary magnet mmf.

Claim 16

An air core gauge for driving a mechanical indicator proportionally to the value of a remote condition, comprising: two angularly related coils, input signal means responsive to the remote condition for varying the current flow through the coils and the resulting mmfs to drive a mechanical indicator from a zero position to a maximum value position, fixed force means for continuously providing a force on the indicator in a first direction to bias the indicator toward its zero position, a compensating coil for the fixed force means that produces a force on the indicator in the same first direction as the first force means so that said fixed force means and said compensating coil bias the indicator to its zero position with supply voltage applied to the coils with no input signal present.

Claim 17

An air core gauge for driving a mechanical indicator proportionally to the value of a remote condition, comprising: two angularly related coils, input signal means responsive to the remote condition for varying the current flow through the coils and the resulting mmfs to drive a mechanical indicator from a zero position to a maximum value position, fixed force means for continuously providing a force on the indicator in a first direction to bias the indicator toward its zero position, a compensating coil for the fixed force means that produces a force on the indicator in the same first direction as the first force means so that said fixed force means and said compensating coil bias the indicator to its zero position with supply voltage applied to the coils with no input signal present.

Claim 18

An air core gauge for driving a mechanical indicator proportionally to the value of a remote condition, comprising: a magnetic rotor, at least two angularly related coils surrounding the rotor, input signal means responsive to the remote condition for varying the current flow through the coils and the resulting mmfs to drive a mechanical indicator connected to the rotor from a zero position to a maximum value position, fixed force means for continuously biasing the indicator toward its zero position generally in force and directional alignment with the mmf of one of the coils, said fixed force means being spaced axially a substantial distance from both the coils and the rotor on the side of the coils opposite the rotor and the indicator so that the force of the fixed force means can be varied during gauge calibration without affecting the magnetic rotor.

Claim 19

An air core gauge for driving a mechanical indicator proportionally to the value of a remote condition, comprising: a magnetic rotor, at least two angularly related coils surrounding the rotor, input signal means responsive to the remote condition for varying the current flow through the coils and the resulting mmfs to drive a mechanical indicator connected to the rotor from a zero position to a maximum value position, fixed force means for continuously biasing the indicator toward its zero position generally in force and directional alignment with the mmf of one of the coils, said fixed force means being spaced axially a substantial distance from both the coils and the rotor on the side of the coils opposite the rotor and the indicator so that the force of the fixed force means can be varied during gauge calibration without affecting the magnetic rotor.

Claim 20

An air core gauge for driving a mechanical indicator proportionally to the value of a remote condition, as defined in claim 13, wherein the fixed force means is a permanent magnet, and flux varying means for changing the strength of the permanent support during gauge calibration without changing the strength of the magnetic rotor.

Claim 21

An air core gauge for driving an indicator pointer to an angular position proportionally to the value of a sensed condition, as defined in claim 13, including a printed circuit board mounted adjacent but spaced from the coils and the rotor, said fixed force means including a permanent magnet mounted on the printed circuit board.

Claim 22

An air core gauge for driving a mechanical indicator proportionally to the value of a remote condition, comprising: a magnetic rotor, two angular related rotor driving coils surrounding the rotor providing mmfs in first and second orthogonally related directions, input signal means responsive to the remote condition for varying the current flow through the coils substantially equally to produce resulting mmfs to drive a mechanical indicator connected to the rotor from a zero position to a maximum value position, a third coil producing a substantially constant mmf aligned oppositely in one of the first and second directions, fixed force means for continuously producing a force in the opposite direction of one of the angularly related coils and in the same direction as the third coil mmf to bias the indicator toward its zero position, the strength of the third coil being selected to compensate for the fixed force means without a separate compensating coil.

Claim 23

An air core gauge for driving a mechanical indicator proportionally to the value of a remote condition, comprising: a magnetic rotor, two angular related rotor driving coils surrounding the rotor providing mmfs in first and second orthogonally related directions, input signal means responsive to the remote condition for varying the current flow through the coils substantially equally to produce resulting mmfs to drive a mechanical indicator connected to the rotor from a zero position to a maximum value position, a third coil producing a substantially constant mmf aligned oppositely in one of the first and second directions, fixed force means for continuously producing a force in the opposite direction of one of the angularly related coils and in the same direction as the third coil mmf to bias the indicator toward its zero position, the strength of the third coil being selected to compensate for the fixed force means without a separate compensating coil.

Claim 24

An air core gauge as defined in claim 16, wherein the fixed force means is a permanent magnet.