| 摘要 |
<p>A valve has an operating mechanism which comprises a lever (2) having a projection engageable in and disengageable from formations in fixed and moveable superposed stop plates (6) and (5). Plate (6) has long and short peripheral formations and plate (5) has a short peripheral formation (23). By placing the projection on the lever (2) in the formation (23) the position of the stop provided by that formation may be adjusted in a continuously variable manner between the limits provided by the long formation in plate (6) relative to plate (6) until the stop position appropriate to a desired open position of the valve is reached and then locked in that position relative to plate (6) so that thereafter the desired degree of valve opening can be quickly and easily achieved.</p> |
