Robertshaw Controls Company

Charles E Barker

Frederick T Bauer

Anthony C Cairo

Auzville Jackson, Jr

A wall mounted programmable thermostat is provided with a cover plate that normally overlies a portion of a keyboard selector portion and is pivotally mounted so as to open downwardly. The inner cover face has written operating instructions thereon.

Wall thermostat and the like

Apparatus is provided for a wall mounted thermostat to accept and convert manually generated instructions to binary encoded electronic impulses to control ambient air conditions in the environment in which the thermostat is located. The parameters of operation include a building heating control which reduces the desired ambient temperature at night, beginning at a prescribed time and returning to a higher daytime level at a different prescribed time. The system may also adjust desired temperature depending upon humidity conditions and alter the timing of heating and air conditioning control by predicting when a desired temperature will be reached in order to avoid overshoot. The system includes a liquid crystal or light emitting diode display and communicates with a power source and with heating and air conditioning switches such as relays or contactors.

A clock circuit designed to keep time based upon a known frequency of an alternating current power supply is provided with a d.c. power backup system to operate the clock circuit during periods of a.c. power failure. The clock circuit includes a high frequency oscillator which generates a large number of timing pulses for each alternating current power cycle. During periods of normal operation on alternating current power, the number of oscillator timing pulses occurring between successive null points in the alternating current power supply waveform are counted and stored. When the clock circuit is operated from the d.c. power supply during periods of a.c. power failure, the last count of timing pulses between successive null points in the a.c. cycle is loaded as an initial count into a counter. The counter is decremented down to zero, whereupon the counter registers the passage of a period of time corresponding to the time interval between two null points in the a.c. power cycle, at that time no longer present. This count is used to update a time recorder to maintain accurate time even during periods of power failure.

Self-calibrating electric clock circuit

A microwave oven cooking control system is provided with a comestible probe for temperature sampling. The comestible probe is only intermittently energized so that self-heating is avoided. Energization of the probe is under the control of a timing mechanism, which concurrently produces a voltage signal that rapidly increments in steps corresponding to possible internal temperatures of the comestible. The voltage signal is compared against a reference voltage level, which in turn is governed by the internal temperature of the comestible as sensed by the probe. The comparison results are used to deactuate energization of the probe and to control the microwave energy transmitted to the comestible by the microwave oven magnetron. A threshold a.c. current detector is also connected to said magnetron control to deactuate operation of the magnetron when a low amplitude a.c. power signal is received.

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Holland, MI, United States of America

Charles E Barker