Patent ID: 7217160

Claim:
An adapter comprising: a body including a first bore provided at one end, an intermediate second bore having a diameter larger than that of the first bore, a third bore provided at the other end and having a diameter larger than that of the second bore, a first shoulder provided between the first and the second bores, and a second shoulder provided between the second and the third bores; a first polytetrafluorethylene block adapted to be received in the intermediate second bore; a second polytetrafluoroethylene block adapted to be received in the third bore and including a metal ring secured onto one portion of the second polytetrafluoroethylene block; a central transmission rod including an intermediate toothed ring provided on its outer surface, a first port provided at one end and inserted through said first polytetrafluoroethylene block until said first polytetrafluoroethylene block is against the toothed ring, a second port provided at the other end and inserted through said second polytetrafluoroethylene block until a portion of the toothed ring is within the second polytetrafluoroethylene block, and a tapered protrusion formed around the first port and protruding from the first polytetrafluoroethylene block, with said transmission rod being placed into the body so that there are spaces around the tapered protrusion and between the first and second polytetrafluoroethylene blocks; whereby the contact area of the body and the first and second polytetrafluoroethylene blocks is decreased and air fills said spaces so as to create air insulation.