Piston and cylinder type thermal device part therefor and methods of

Abstract

A piston and cylinder type thermal device and method of making the same are provided, the device having a cylinder member carrying a piston stem that has an outer end that projects out of the opening of an end of the cylinder member to be extended and retracted relative thereto upon changes of sensed temperature of a charge of material disposed in the cylinder member that operatively acts on a resilient stem seat disposed in the cylinder member and having an opening at one end thereof that receives an inner end of the stem therein. The stem has a lubricant thereon to tend to prevent abrasion between the stem and the seat during the extended and retracted movement therebetween. A lubricant storage unit is carried by the device and has therein a porous member with the lubricant absorbed therein and being operatively associated with the stem for applying the lubricant to the stem external of the end of the cylinder member during movement of the stem relative to the stem seat. The lubricant storage unit comprises a cup-shaped member having a closed end and an open end with the open end being telescoped on and secured to the end of the cylinder member in such a manner that the porous member is placed under axial compression between and against the end of the cylinder member and the closed end of the cup-shaped member.