Viscous fan drive and axially movable valve element

Claim 1

In a remote temperature-sensing fluid coupling device of the type including a first rotatable coupling member defining an axis of rotation, cover means associated with said first member to define a fluid chamber therebetween, means disposed to separate said fluid chamber into a fluid operating chamber and a fluid reservoir chamber, a second rotatable coupling member disposed in said fluid operating chamber and being rotatable relative to said first coupling member, valve means being operable to control the flow of fluid between said reservoir chamber and said operating chamber, and including a fill port and an elongated valve member oriented generally transverse to said axis and disposed to have at least a portion thereof move axially between first and second positions in response to variations in an axial input, characterized by: (a) said first coupling member defining an annular surface portion oriented generally parallel to said axis of rotation, said annular surface portion comprising a peripheral boundary of said fluid reservoir chamber, said annular surface portion defining said fill port, said first coupling member further defining fluid passage means communication between said fill port and said fluid operating chamber; and (b) said valve member including a flow control portion disposed to prevent substantial fluid flow through said fill port when said valve member is in said first position, and to permit substantial fluid flow through said fill port when said portion of said valve member moves axially from said first position to said second position.