| 摘要 |
1,184,655. Valves; brakes. HIGH TEMPERATURE ENGS. Ltd. 30 May, 1967 [27 May, 1966], No. 23989/66. Headings F2E and F2V. A rotary bath valve has seats for the ball, each seat consisting of a ring 12 of relatively rigid material such as P.T.F.E. which engages the ball, and a second ring 11 of elastomeric material which urges the first ring against the ball. The first ring has a chamfer 15 next to the ball and a circle of contact B between the two rings is of greater diameter than a contact circle A against the ball. Fluid trapped in the chamber 14 can escape past the ring 12 if it expands by rise of temperature. The ball is driven by an electric motor (16) Figs. 3 and 4 (not shown), through gearing consisting of a worm and wheel (17, 18) . The wheel is rotatable on a drive shaft (24) coupled to the ball and carries a pinion 19 geared to a layshaft (21) in turn geared to a quadrant (23) on the drive shaft. Diametrically opposite the quadrant is a nose 25 which operates micro-switches (26, 27) to stop the motor at the open and shut positions of the valve. The drive is further arrested by a brake, in that a loose ball (29, Fig. 4) carried by an arm (37) on the drive shaft, is pressed by a fixed cam surface (32) on to the wheel (18) so as to deform this wheel resiliently into frictional engagement with a housing (33) of the layshaft.
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