VENTIL.

摘要

PCT No. PCT/GB90/00165 Sec. 371 Date Jul. 17, 1991 Sec. 102(e) Date Jul. 17, 1991 PCT Filed Feb. 1, 1990 PCT Pub. No. WO90/08566 PCT Pub. Date Aug. 9, 1990.Axial displacement between two components of a valve occurs as a result of relative rotation through the cooperation of helical ramps. Preferably another pair of helical ramps is provided concentric with the first but angularly offset 180 DEG with the result that when the components are at maxinum axial separation the residual contact between the ramps of each pair (shaded areas in FIG. 5e) will be on opposite sides of the axis x of rotation and prolongation, thus preventing tilting of the one component out of axial alignment with the other component. In other constructions more than two pairs of ramps are employed. The ramp means of the invention replaces a screw-thread to provide adjustment of the loading of a valve spring and permits the use of more economical manufacturing and assembly techniques.