Electromechanical oscillator for controlling a timing motor

Claim 2

In a timing device the combination of: a mechanical resonant device; an oscillator circuit including said mechanical resonant device for providing an electric signal having a frequency controlled by the frequency of mechanical oscillation of said mechanical resonant device; means for providing said electrical signal with a selected duty cycle, said duty cycle being the ratio of time said signal is on per cycle; a motor including: a stator of magnetic material providing at least a pair of opposed pole faces with an airgap between; a stator winding magnetically couplEd to said stator; and a rotor having a plurality of teeth of magnetic material adapted to rotate through said airgap, said rotor having a selected magnetic working area ratio defined by the ratio of the width of said teeth to the distance between the centers of said teeth, circuit means coupling said oscillator circuit to said stator winding to energize said winding with a current pulse energizing signal, having a frequency likewise controlled by said frequency of mechanical oscillation, and having a selected current pulse duty cycle wherein the magnetic working area ratio of said rotor is approximately the same as said selected current pulse duty cycle.

Claim 3

A timing device according to claim 1 wherein said mechanical resonant device is a tuning fork.

Claim 4

A timing device according to claim 1 wherein the width of said stator pole faces is substantially the same as the width of said rotor teeth.

Claim 5

A timing device according to claim 1 wherein said selected current pulse duty cycle and said rotor magnetic working area ratio are each approximately 1:3.

Claim 6

In a timing device the combination of; a mechanical resonant device; an oscillator circuit including said resonant device for providing an electrical output signal; said output signal having a predetermined frequency controlled by the frequency of mechanical oscillation of said resonant device, and said output signal having a selected duty cycle, said duty cycle being the ratio of the time said signal is on per cycle; a motor including: a stator of magnetic material providing at least a pair of opposed pole faces with an airgap therebetween; a stator winding magnetically coupled to said stator, and a rotor having a plurality of teeth of magnetic material adapted to rotate through said airgap, said rotor having a selected magnetic working area ratio defined by the ratio of the width of said teeth to the distance between the centers of said teeth; a source of electrical energy; circuit means coupled to said source and between said oscillator and said stator winding to energize said winding with successive current pulses at said predetermined frequency and at a selected current pulse duty cycle, each of said current pulses including: a first interval corresponding in time to the oscillator pulse width during which electrical energy is supplied to said winding from said source, and a second interval during which the current flow through said winding decays wherein said magnetic working area ratio of said rotor is substantially the same as said selected current duty cycle.

Claim 7

In a timing device the combination of; a mechanical resonant device; an oscillator circuit including said resonant device for providing an electrical output signal; said output signal having a predetermined frequency controlled by the frequency of mechanical oscillation of said resonant device, and said output signal having a selected duty cycle, said duty cycle being the ratio of the time said signal is on per cycle; a motor including: a stator of magnetic material providing at least a pair of opposed pole faces with an airgap therebetween; a stator winding magnetically coupled to said stator, and a rotor having a plurality of teeth of magnetic material adapted to rotate through said airgap, said rotor having a selected magnetic working area ratio defined by the ratio of the width of said teeth to the distance between the centers of said teeth; a source of electrical energy; circuit means coupled to said source and between said oscillator and said stator winding to energize said winding with successive current pulses at said predetermined frequency and at a selected current pulse duty cycle, each of said current pulses including: a first interval corresponding in time to the oscillator pulse width during which electrical energy is supplied to said winding from said source, and a second interval during which the current flow through said winding decays wherein said magnetic working area ratio of said rotor is substantially the same as said selected current duty cycle.

Claim 8

Timing apparatus according to claim 5 wherein said circuit means includes a unidirectional shunt path across said winding to form a closed circuit loop with said winding, the resistance and inductance in said loop being selected to control said second interval to achieve the desired current duty cycle.

Claim 9

Timing apparatus according to claim 5 wherein said mechanical resonant device is a tuning fork.

Claim 10

Timing apparatus according to claim 5 wherein said mechanical resonant device is a crystal.

Claim 11

In a timing device, the combination of: a mechanical resonant device; an oscillator circuit including said resonant device for providing an electrical output signal having a frequency controlled by the frequency of mechanical oscillation of said resonant device; a synchronous motor; a source of electrical energy; circuit means coupled to said source and between said oscillator and said motor for driving said motor; the improvement being means for preventing variations in said source of electrical energy from causing the amplitude of said electrical output signal of said oscillator circuit to also vary, said means including at least one forward-biased semiconductor junction connected across said oscillator circuit so as to provide a stable source of operating voltage for said oscillator circuit independent of said energy source Variations.

Claim 12

In a timing device, the combination of: a mechanical resonant device; an oscillator circuit including said resonant device for providing an electrical output signal having a frequency controlled by the frequency of mechanical oscillation of said resonant device; a synchronous motor; a source of electrical energy; circuit means coupled to said source and between said oscillator and said motor for driving said motor; the improvement being means for preventing variations in said source of electrical energy from causing the amplitude of said electrical output signal of said oscillator circuit to also vary, said means including at least one forward-biased semiconductor junction connected across said oscillator circuit so as to provide a stable source of operating voltage for said oscillator circuit independent of said energy source Variations.

Claim 13

A timing device according to claim 9 wherein said means for preventing amplitude variations includes: a forward-biased diode connected across said oscillator circuit, and resistive means connected between said diode and said energy source.

Claim 14

In a timing device, the combination of: a mechanical resonant device; an oscillator circuit including said resonant device for producing an electrical output signal having a frequency controlled by the frequency of mechanical oscillation of said resonant device, and including successive pulses; a synchronous motor; a source of electrical energy; circuit means coupled to said source and between said oscillator and said motor for driving said motor with successive current pulses at a selected current pulse duty cycle; the improvement being means for substantially preventing variations in the ambient temperature from altering said current pulse duty cycle, said means including at least one forward-biased semiconductor junction connected across said oscillator circuit so as to provide a source of operating voltage for said oscillator circuit, and semiconductor switch means included within said circuit means and connected between said oscillator circuit and said motor so that variations in the forward-biased semiconductor junction with temperature compensate for the variations of the parameters of said switch means with temperature.

Claim 15

In a timing device, the combination of: a mechanical resonant device; an oscillator circuit including said resonant device for producing an electrical output signal having a frequency controlled by the frequency of mechanical oscillation of said resonant device, and including successive pulses; a synchronous motor; a source of electrical energy; circuit means coupled to said source and between said oscillator and said motor for driving said motor with successive current pulses at a selected current pulse duty cycle; the improvement being means for substantially preventing variations in the ambient temperature from altering said current pulse duty cycle, said means including at least one forward-biased semiconductor junction connected across said oscillator circuit so as to provide a source of operating voltage for said oscillator circuit, and semiconductor switch means included within said circuit means and connected between said oscillator circuit and said motor so that variations in the forward-biased semiconductor junction with temperature compensate for the variations of the parameters of said switch means with temperature.

Claim 16

A timing device according to claim 11 wherein: said semiconductor junction is a diode which is connected to said energy source through resistive means, and the semiconductor switch means is a transistor wherein the variation of the base-to-emitter voltage with temperature is the principal parameter compensated by said diode.