Importance

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Abstract

Automatic temperature control system for vehicles commonly utilize vacuum pressure as a power source to perform various functions such as operating the mode damper which routes hot or cold air through either lower or upper outlets. The vacuum pressure is directed to the vacuum motor or actuator to the mode door by a vacuum switch. Normally, the switch is of the type having a stationary ported member and an overlying member which is movable to interconnect the various ports. Undesirable split modes of operation occur because of either improper placement of the rotatable switch member or excessive leakage thereby. Split mode operation may undesirably cause improper allocation of hot and cold air through upper and lower outlets. The subject application provides a vacuum switching device or 'toggle' located between the vacuum switch and the vacuum or actuator motor. It operates in response to vacuum input to modify vacuum pressure so that the signal to the vacuum motor is either low or high, which action eliminates split mode operation caused by more intermediate vacuum pressures.

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First Claim