Gas filled swivel joint for cryogenic heat pipes

A movable heat conductive joint structure for an assembly subjected to vacuum and low temperature conditions, said joint structure comprising:

• first and second heat pipes,
• interengaging, relatively movable heat conductive heat pipe support members, said heat pipe support members being fixed respectively to said heat pipes,
• one of said support members comprising a socket assembly defining a spherical cavity and the other support member comprising a ball member of slightly smaller diameter than that of said spherical cavity and being carried within said spherical cavity and movable orthogonally with respect to said socket assembly,
• said socket assembly comprising a large diameter opening within one end of the same,
• said ball member having a shaft projecting radially through said large diameter opening and thermally coupled to said first heat pipe member, said ball member and said socket assembly forming a gap,
• said socket assembly comprising a cylindrical opening fixedly receiving one end of said other heat pipe,
• means for maintaining a gas under light pressure within said gap to effect a low impedance heat path across said gap and between said heat pipe support members without impedance to the relative movement of said support members,
• said means for maintaining a gas under light pressure within said gap comprising fluid passage means extending through said socket assembly and opening into said spherical cavity for directing gas under pressure to said gap at the side of said socket assembly opposite that of said large diameter opening through which the ball member shaft projects, and
• said socket assembly further comprising an annular groove concentric with said fluid passageway within said spherical cavity and adjacent said large diameter opening,
• annular resilient seal means carried within said annular groove in sealing contact with the periphery of said ball and at least one surface of said groove to prevent escape of low pressure gas from said gap through said large diameter opening,
• a second annular groove within said socket assembly cavity coaxial with said first groove and positioned intermediate of said first groove and said gas passage, and
• split ring means positioned within said groove and in contact with the periphery of said ball for maintaining said gap between said ball and said spherical cavity wall and for permitting distribution of said low pressure gas between the opposed surfaces of the ball periphery and the socket cavity to effect creation of a low thermal impedance path between said ball and socket members.