Electromechanical valve positioning apparatus

Claim 2

A bidirectional motor control circuit comprising: first means for receiving first signals which indicate that the motor is to be driven in a first direction; second means for receiving second signals which indicate that the motor is to be driven in a second direction; a first drive circuit, responsive to said first receiving means; for driving the motor in said first direction while said first signals are being received; a second drive circuit, responsive to said second receiving means, for driving the motor in said second direction while said second signals are being received; a first timing circuit responsive to said first receiving means and adapted to disable said first drive circuit after said first signals have been received for a predetermined period; a second timing circuit responsive to said second receiving means and adapted to disable said second drive circuit after said second signals have been received for a predetermined period; first means for resetting said first timing circuit in response to said second receiving means receiving a second signal; second means for resetting said second timing circuit in response to said first receiving means receiving a first signal; and means for braking said motor when neither said first nor said second signals are being received by said first and second receiving means or when one of said drive circuits is disabled.

Claim 3

The control circuit as recited in claim 1 wherein: the motor comprises a plurality of coils which are adapted to receive an alternating voltage for driving the motor; and wherein said braking means comprises: a source of D.C. voltage, at least one gate adapted to apply said D.C. voltage to at least one of said coils to brake the motor, and means for periodically enabling said gate when said first and second signals are not being received or when one of said drive circuits is disabled.

Claim 4

The control circuit as recited in claim 2 wherein said D.C. voltage is periodically applied to all said coils by said gate.

Claim 5

A bidirectional motor control circuit comprising: first means for receiving first signals which indicate that the motor is to be driven in a first direction; second means for receiving second signals which indicate that the motor is to be driven in a second direction; a first drive circuit, responsive to said first receiving means, for driving the motor in said first direction while said first signals are being received; a second drive circuit, responsive to said second receiving means, for driving the motor in said second direction while said second signals are being received; a first timing circuit responsive to said first receiving means and adapted to disable said first drive circuit after said first signals have been received for a predetermined period; a second timing circuit responsive to said second receiving means and adapted to disable said second drive circuit after said second signals have been received for a predetermined period; first means for resetting said first timing circuit in response to said second receiving means receiving a second signal; and second means for resetting said second timing circuit in response to said first receiving means receiving a first signal; each said timing circuit comprising: a capacitor, means for charging said capacitor while said timing circuit''s associated sIgnal is being received, a circuit element connected to said capacitor and adapted to fire an output in response to said capacitor being charged to a predetermined level, and gating means adapted to be operated in response to firing of said element for disabling the drive circuit associated with said timing circuit when said capacitor has been charged to said predetermined level; each said timing circuit further including a blocking diode for preventing discharge of said capacitor while said timing circuit''s associated signal is not being received and when said charging means is inoperative.

Claim 6

A bidirectional motor control circuit comprising: first means for receiving first signals which indicate that the motor is to be driven in a first direction; second means for receiving second signals which indicate that the motor is to be driven in a second direction; a first drive circuit, responsive to said first receiving means, for driving the motor in said first direction while said first signals are being received; a second drive circuit, responsive to said second receiving means, for driving the motor in said second direction while said second signals are being received; a first timing circuit responsive to said first receiving means and adapted to disable said first drive circuit after said first signals have been received for a predetermined period; a second timing circuit responsive to said second receiving means and adapted to disable said second drive circuit after said second signals have been received for a predetermined period; first means for resetting said first timing circuit in response to said second receiving means receiving a second signal; and second means for resetting said second timing circuit in response to said first receiving means receiving a first signal; each said timing circuit comprising: a capacitor, means for charging said capacitor while said timing circuit''s associated sIgnal is being received, a circuit element connected to said capacitor and adapted to fire an output in response to said capacitor being charged to a predetermined level, and gating means adapted to be operated in response to firing of said element for disabling the drive circuit associated with said timing circuit when said capacitor has been charged to said predetermined level; each said timing circuit further including a blocking diode for preventing discharge of said capacitor while said timing circuit''s associated signal is not being received and when said charging means is inoperative.

Claim 7

A bidirectional motor control circuit comprising: first means for receiving first signals which indicate that the motor is to be driven in a first direction; second means for receiving second signals which indicate that the motor is to be driven in a second direction; a first drive circuit, responsive to said first receiving means, for driving the motor in said first direction while said first signals are being received; a second drive circuit, responsive to said second receiving means, for driving the motor in said second direction while said second signals are being received; a first timing circuit responsive to said first receiving means and adapted to disable said first drive circuit after said first signals have been received for a predetermined period; a second timing circuit responsive to said second receiving means and adapted to disable said second drive circuit after said second signals have been received for a predetermined period; first means for resetting said first timing circuit in response to said second receiving means receiving a second signal; and second means for resetting said second timing circuit in response to said first receiving means receiving a first signal; each said timing circuit comprising: a capacitor, means for charging said capacitor while said timing circuit''s associated signal is being received, a unijunction transistor connected to said capacitor and adapted to fire an output in response to said capacitor being charged to a predetermined level, and gating means adapted to be operated in response to firing of said unijunction transistor for disabling the drive circuit associated with said timing circuit when said capacitor has been charged to said predetermined level; each said timing circuit further including means for isolating said capacitor from said unijunction transistor when said capacitor is not being charged to avoid leakage of the charge on said capacitor.

Claim 8

A bidirectional motor control circuit comprising: first means for receiving first signals which indicate that the motor is to be driven in a first direction; second means for receiving second signals which indicate that the motor is to be driven in a second direction; a first drive circuit, responsive to said first receiving means, for driving the motor in said first direction while said first signals are being received; a second drive circuit, responsive to said second receiving means, for driving the motor in said second direction while said second signals are being received; a first timing circuit responsive to said first receiving means and adapted to disable said first drive circuit after said first signals have been received for a predetermined period; a second timing circuit responsive to said second receiving means and adapted to disable said second drive circuit after said second signals have been received for a predetermined period; first means for resetting said first timing circuit in response to said second receiving means receiving a second signal; and second means for resetting said second timing circuit in response to said first receiving means receiving a first signal; each said timing circuit comprising: a capacitor, means for charging said capacitor while said timing circuit''s associated signal is being received, a unijunction transistor connected to said capacitor and adapted to fire an output in response to said capacitor being charged to a predetermined level, and gating means adapted to be operated in response to firing of said unijunction transistor for disabling the drive circuit associated with said timing circuit when said capacitor has been charged to said predetermined level; each said timing circuit further including means for isolating said capacitor from said unijunction transistor when said capacitor is not being charged to avoid leakage of the charge on said capacitor.

Claim 9

The control circuit as recited in claim 5 wherein said isolating means comprises a switching transistor connected between said capacitor, said unijunction transistor and said charging means, said switching transistor being adapted to operatively connect said capacitor and unijunction transistor only during operation of said charging means.

Claim 10

The control circuit as recited in claim 5 wherein said isolating means comprises: a voltage source; a field effect transistor connected to said voltage source and between said capacitor and said unijunction transistor such that said field effect transistor is gated by the charge on said capacitor to pass a voltage corresponding to said charge to said unijunction transistor.

Claim 11

A time motor control circuit comprising: means for driving the motor; a capacitor; means for charging said capacitor, said charging means adapted to operate intermittently and further including a blocking diode for preventing discharge of said capacitor when said capacitor is not being charged; a circuit element connected to said capacitor and adapted to fire an output in response to said capacitor being charged a predetermined level; and gating means adapted to be operated in response to firing of said element for controlling said driving means when said capacitor has been charged to said predetermined level.

Claim 12

A time motor control circuit comprising: means for driving the motor; a capacitor; means for charging said capacitor, said charging means adapted to operate intermittently and further including a blocking diode for preventing discharge of said capacitor when said capacitor is not being charged; a circuit element connected to said capacitor and adapted to fire an output in response to said capacitor being charged a predetermined level; and gating means adapted to be operated in response to firing of said element for controlling said driving means when said capacitor has been charged to said predetermined level.

Claim 13

A timed mOtor control circuit comprising: means for driving the motor; a capacitor; means for charging said capacitor; a unijunction transistor connected to said capacitor and adapted to fire an output in response to said capacitor being charged to a predetermined level; gating means adapted to be operated in response to firing of said unijuntion transistor for controlling said driving means when said capacitor has been charged to said predetermined level; and means for isolating said capacitor from said unijunction transistor when said capacitor is not being charged to avoid leakage of the charge on said capacitor.

Claim 14

A timed mOtor control circuit comprising: means for driving the motor; a capacitor; means for charging said capacitor; a unijunction transistor connected to said capacitor and adapted to fire an output in response to said capacitor being charged to a predetermined level; gating means adapted to be operated in response to firing of said unijuntion transistor for controlling said driving means when said capacitor has been charged to said predetermined level; and means for isolating said capacitor from said unijunction transistor when said capacitor is not being charged to avoid leakage of the charge on said capacitor.

Claim 15

The control circuit as recited in claim 9 wherein said isolating means comprises a switching transistor connected between said capacitor, said unijunction transistor, and said charging means, said switching transistor being adapted to operatively connect said capacitor and unijunction transistor only during operation of said charging means.

Claim 16

The control circuit as recited in claim 9 wherein said isolating means comprises: a voltage source; a field effect transistor connected to said voltage source and between said capacitor and said unijunction transistor such that said field effect transistor is gated by the charge on said capacitor to pass a voltage corresponding to said charge to said unijunction transistor.