Abstract: The present invention is directed at a thermostat using a clock burst to control a temperature trip point without the use of an external resistor. A clock burst is applied to a clock input pin from which a counter is used to count the number of pulses. The output of the counter is used to drive a DAC that sets the trip point. No external resistor is needed. This trip point provides a low pin count, flexibility, and high accuracy.

Abstract: A displacement control apparatus is used for a variable displacement compressor. The compressor is driven by an internal combustion engine. The compressor has an inclining swash plate and a piston, which is reciprocated by the swash plate. The stroke of the piston is changed in accordance with the inclination angle of the swash plate. The displacement of the compressor is changed between a minimum displacement and a maximum displacement in accordance with the stroke of the piston. The apparatus includes an actuator coupled to the swash plate. The actuator is actuated by exhaust pressure or intake pressure from the engine. A controller changes the inclination angle of the swash plate by actuating the actuator.

Abstract: A climate control system is provided including a vacuum pump for generating a vacuum upon actuation. Also included is a thermostat for generating the activation signal upon a current temperature within the associated room being out of a predetermined range. At least one vent assembly is provided including a plurality of vanes pivotally mounted within the frame and having an unbiased open orientation for allowing the flow of air into the associated room and a biased closed orientation for precluding the flow of air into the associated room and a pneumatic servo connected to each of the vanes and in communication with the vacuum pump. The servo is adapted to transfer the vanes of the vent assembly to the closed orientation thereof only upon the receipt of vacuum. Finally, a vacuum valve is connected between the vacuum pump and the servo of the vent assembly. Such vacuum valve is connected to the thermostat for supplying the same with a vacuum during the receipt of the activation signal.

Abstract: A timed rate control applies to a system having a device 12 for varying a medium 14, a sensor 13 for detecting variation in the medium, and a pneumatic line 11 for varying the device 12 in response to the sensor. This includes many pneumatic control systems that the invention can effectively stabilize to reduce fluctuation and improve operating accuracy and efficiency. The pneumatic line is opened and closed by a solenoid valve 17, and a setable timer 18 variably determines both closed and open intervals for the solenoid valve. The timer is connected to the solenoid valve to control alternate operation between the closed and open intervals while the system operates. This limits each adjustment to a brief duration separated by inactive periods that allow the system to stabilize.

Abstract: A fluid pressure and electrical signal controller for providing a predetermined regulated vacuum signal from a variable source in response to changes in position of a rotatable input shaft when attached thereto and an electrical signal at a predetermined position of the input shaft. A pressure force balance type vacuum modulator valve is preloaded and biased by a spring connected to a cam follower which tracks a rotary cam turned by the input shaft. The modulator valve is slidably attached to the controller body for adjusting the preload length of the spring and a rotatable adjustment ring engages the valve and is threadedly received on the controller body for effecting sliding adjustment of the valve position on the controller body.