Thermostatic control apparatus for operation between the heating and cooling mode

A thermostat control apparatus for operating a heating system in one mode and a cooling system in another mode and operative to maintain a given temperature differential between said heating and cooling modes wherein the temperature of an environment monitored by said thermostat control apparatus is maintained at a value according to said temperature differential, comprising:

• a bimetallic temperature sensing means operative to detect the temperature of said environment and providing a displacement according to temperature changes;
• a first mercury switch coupled to said bimetallic sensing means and oriented at a given angle with respect thereto, said switch having a common contact, a normally closed contact and a normally opened contact, where said common contact and said normally closed and opened contacts are connected according to the position of a pool of mercury associated with said switch, whereby in one mode said normally opened contact is connected to said common contact and in a second mode said normally closed contact is connected to said common contact;
• a second mercury switch coupled to said bimetallic sensing means and oriented at a given angle with respect to said first switch with said angle selected according to said given temperature differential, said second switch having a common contact, a normally opened contact and a normally closed contact and operative in a first mode wherein said common contact is connected to said normally opened contact by a pool of mercury associated with said switch and in a second mode said common contact is connected to said normally closed contact, with said common contact of said first switch connected to a point of operating potential, with said normally closed contact of said first switch connected to said common contact of said second switch, with said normally opened contact of said first switch connected to a heating terminal for activation of said heater system in said second mode of said first switch, with said normally closed contact of said second switch connected to a fan terminal for activation of a fan unit during said second mode of said second switch, and with said normally opened contact of said second switch connected to a cooling terminal for activation of said cooling system in said first mode of said second switch, whereby for a temperature below a given value said first switch operates in said second mode to energize said heating system and when said temperature rise a specified amount above said given value said first switch operates in said first mode whereby said second switch operates in said second mode to activate said fan, wherein as the temperature rises an amount above said specified amount said bimetallic means operates said second second switch in said first mode with said first switch operated in said first mode to activate said cooling system via said second switch and when said temperature falls said specified amount said second switch is operated in said second mode with said first switch remaining in said first mode until said temperature again falls below said given value.