Automatic on/off digitally timed electronic switch

• US 4,112,764 A
• Filed: 01/12/1977
• Issued: 09/12/1978
• Est. Priority Date: 01/12/1977
• Status: Expired due to Term

• Current Assignee: American Medical Electronics, Inc. (Orthofix Medical Inc.)
• Original Assignee: Johnson & Johnson
• Inventors: Turner, Robert B.
• Primary Examiner(s): Gill, James J.
• Application Number:
  US05/758,618
• Time in Patent Office: 608 Days
• Field of Search: 73/362 AR, 307/293, 328/129
• US Class Current: 374/142
• CPC Class Codes: G01K 13/20 Clinical contact thermometers for use with humans or animals
• CPC Class Codes: G01K 7/00 Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat giving results other than momentary value of temperature G01K3/00 ; Power supply therefor, e.g. using thermoelectric elements
• CPC Class Codes: H03K 17/28 Modifications for introducing a time delay before switching modifications to provide a choice of time-intervals for executing more than one switching action H03K17/296

Abstract

An electronic thermometer system is disclosed including a circuit for measuring temperature variations, a time measuring circuit, a display for consecutive display of time and temperature, and an automatic digitally timed electronic switch.

The automatic on/off digitally timed electronic switch is responsive to momentary operation of an actuator to turn on and remain on through a predetermined interval including an electronic switch having a latching circuit adapted for connection to a power supply; a drive circuit is responsive to momentary supply of power by operation of the actuator to provisionally begin operating and provide a gating signal to operate the latching circuit; means is provided interconnecting the latching circuit and drive circuit for continuing operation of the drive circuit independent of the momentary supply of power; and a digital timer circuit including counting means is responsive to momentary operation of the actuator to begin counting and provide at a predetermined count an output to inhibit further operation of the drive circuit and deenergize the latching circuit.

Claims

1. In an electronic thermometer system comprising:

power supply means;

a temperature measuring circuit for measuring temperature variations and providing a signal representative thereof;

normally open actuator switch means having a momentary closure property;

a time measuring circuit;

a display circuit responsive to said time measuring circuit and said temperature measuring circuit, for indicating the measured temperature during one period and the measured time during another period;

the improvement comprising an automatic on/off digitally timed electronic switch responsive to momentary closure of said actuator means to turn on and remain on for a predetermined interval and thereby to energize said time measuring circuit, said temperature measuring circuit, and said display circuit said automatic on/off switch including;

an electronic switch including a latching circuit means adapted for connection to said power supply means;

interim enabling means activated for a fixed temporary period by closure of said actuator means;

a drive circuit means for operating said time and temperature measuring circuits and said display circuit responsive to said interim enabling means to provisionally begin operating and to provide a gating signal to operate said latching circuit; and

means interconnecting said latching circuit and said drive circuit and responsive to provisional operation of said drive means, for subsequently continuing operation of said drive circuit independent of the momentary enablement of said interim means; and

,

a digital timer circuit including counting means successively responsive to momentary operation of said actuator, and thence to said means for subsequently continuing, to begin counting and provide at a predetermined count an output to inhibit further operation of said drive circuit and deenergize said latching circuit.

2. The system of claim 1 in which said digital timer circuit includes a reset circuit responsive to each momentary application of power effected by operation of the actuator to recycle said counting means and reinitiate the predetermined interval.

3. An automatic on/off digitally timed electronic switch responsive to momentary operation of an actuator means to turn on and remain on for a predetermined interval comprising:

an electronic switch including a latching circuit adapted for connection to a power supply;

interim enabling means, activated for a fixed temporary period by closure of said actuator means;

a drive circuit responsive to said interim enabling means to provisionally begin operating and to provide a gating signal to operate said latching circuit; and

means interconnecting said latching circuit and said drive circuit and responsive to provisional operation of said drive means, for subsequently continuing operation of said drive circuit independent of the momentary enablement by said interim means; and

,

a digital timer circuit including counting means responsive successively to momentary operation of said actuator and thence to said means for subsequently continuing, to begin counting and provide at a predetermined count an output to inhibit further operation of said drive circuit and deenergize said latching circuit.

4. The switch of claim 3 in which said digital timer circuit includes a reset circuit responsive to each momentary application of power effected by operation of the actuator to recycle said counting means and reinitiate the predetermined interval.

5. In an electronic thermometer system comprising;

power supply means;

a temperature measuring circuit for measuring temperature variations and providing a signal representative thereof;

normally open actuator switch means having a momentary closure property;

a time measuring circuit;

a display circuit responsive to said time measuring circuit and said temperature measuring circuit, for indicating the measured temperature during one period and the measured time during another period;

the improvement comprising an automatic on/off digitally timed electronic switch responsive to momentary closure of said actuator means to turn on and remain on for a predetermined interval, and thereby to energize said time measuring circuit, said temperature measuring circuit, and said display circuit, said automatic on/off switch including;

a capacitor;

means responsive to closure of said actuator means for charging said capacitor;

differential amplifier means having first and second input terminals coupled to said capacitor through respective first and second biasing means, said first and second biasing means being operative in opposite complementary fashion in response to select charge levels on said capacitor, said amplifier means having first and second output states in respective association with operation of said first and second biasing means;

latch circuit means, switchably interconnecting said power supply means with said temperature and time measuring circuits and with said display circuit, said latch being in a disconnecting state when said amplifier means output is in said first state, and being in a connecting state when said amplifier means output is in said second state;

whereby momentary charging of said capacitor switches said amplifier means output to said second state, and said latch means locks said amplifier means output in said second state irrespective of discharging of said capacitor.