1. Field of the Invention
This invention relates to a vehicle-type thermostat construction and to a method of making the same.
2. Prior Art Statement
It is known to provide a vehicle-type thermostat construction comprising a temperature responsive device having a piston member and a cylinder member that are adapted to provide relative movement therebetween when the device senses certain temperatures, a valve seat unit being operatively interconnected to one of the members, a valve closure unit being operatively interconnected to the other of the members and being adapted to control fluid flow through the valve seat unit in relation to the position of the valve closure unit relative to the valve seat unit as determined by the temperature being sensed by the device, and spring means operatively interconnected to one of the members and to one of the units to always tend to hold the units against each other in a closed condition to prevent fluid flow through the valve seat unit. For example, see the U.S. Pat. No. 4,091,991 to Sliger, and the U.S. Pat. No. 3,734,405 to Wagner.
It appears that the spring 26 of the patent to Sliger, U.S. Pat. No. 4,091,991 and the springs 56 and 72 of the patent to Wagner, U.S. Pat. No. 3,734,405 do not impose any loading force between the piston and cylinder members 32, 31 and 44, 42 when the respective valve closure units 24 and 62 are disposed against the respective valve seat units 33 and 26.
USPTO Backgrounds
USPTO Backgrounds