Fluid responsive sealed pivot arm means

Claim 1

A fluid response sealed pivot arm means inserted in a fluid chamber portion and responsive to fluid movements in said chamber to physically rock and thereby transmit the movement to the exterior of the chamber, said sealed pivot arm means including, in combination: a. body means communicating with said portion of the fluid chamber and including a bore of given diameter having an increased diameter portion at the end of said bore opening into said fluid chamber; b. an elongated arm means passing through said bore so that an outer end is exterior of the chamber, an inner end is within the chamber, and a central portion is in said bore; c. a pivot pin passing transversely across said bore and into said central portion of said arm means for pivoting the arm means for rocking movement, the central portion of the arm means having a diameter less than said given diameter to define within the inside wall of said bore an annulus; d. a rolling diaphragm having its outer periphery terminating in an annular bead received in said increased diameter portion, the inner portion of said diaphragm being secured to said arm means, the annular portion of the diaphragm between its inner portion and outer periphery folding to define an annular rolling portion filling said annulus between the inner wall of said bore and the outer wall of said central portion of said arm means so that rocking movement of said arm means can be accommodated by said rolling portion of said diaphragm while said diaphragm provides a fluid tight seal between the fluid chamber and exterior; e. a washer assembly overlying said annular bead and secured to said body means to retain the annular bead in said increased diameter portion of said bore; and, f. a flexible boot and filter combination secured to said washer assembly loosely surrounding said inner portion of said arm means for excluding particles in the fluid from passing into said annulus beneath the rolling portion of said diaphragm.