Patent ID: 6988364

Claim:
A thermal actuator comprising: a rigid cup having an open top portion, a closed bottom portion, and a centerline passing through the top and bottom portions, wherein the bottom portion defines a cylindrical cavity having a cavity diameter and filled with thermally responsive wax to an intermediate level within the cup, and the top portion includes an annular first shoulder extending radially outward to a first shoulder diameter at said intermediate level of the cavity, a first cylindrical wall extending axially at said first shoulder diameter, thereby forming a first notch, an annular second shoulder extending radially outward from the first cylindrical wall to a second shoulder diameter, and a tab wall extending from said second shoulder diameter, thereby forming a second notch; a plug having a diaphragm base extending transversely across and sealing the cavity at said intermediate level and a generally cylindrical stem having a diameter less than the cavity diameter and extending axially beyond the top portion of the cup; and a guide having a lower flange portion including a radially outer annular rim bearing against said second shoulder and a radially inner circular ridge bearing against the base of the plug at said cavity diameter, and a tubular portion surrounding and extending axially beyond the stem; said tab at the top portion of the cup being crimped radially inwardly over the flange portion of the guide, whereby the rim of the flange is captured in said second notch and bears against a hard stop defined by the second shoulder of the cup, and the ridge of the flange actuates a first, radially inner seal of the base against the cup first shoulder and extrudes the base into said first notch to from a second, radially outer seal against the first cylindrical wall.