| 摘要 |
<p>A fluid-control valve comprises a piston (16) (Fig. 3 not shown) in a cylinder (7), having a resilient closure surface (19) one one side and a permanent magnet (18) on the other. An operating lever (3) is rotatably mounted by a spindle (5) and carries a permanent magnet (21) at one end. Rotation of the lever (3) to a position where two magnets (21) and (18) are aligned causes the piston (16) to be lifted by magnetic attraction to allow flow from an inlet (11) to an outlet (14). In the embodiment described the valve controls the pneumatic activation of a jacking mechanism controlling a drive cylinder of a bobbin onto which a thread is being wound. The position of the lever (3) is controlled by a feeler (2) Fig. 1 not shown, which bears on the thread (1). If the thread breaks, lever (3) is allowed to rotate to the valve operating position and disengage the drive to the bobbin. When the thread has been joined, lever (3) is rotated to a position where the magnet (21) is aligned with a further piston (17) which lifts to exhaust the jacking circuit through passages (12), (15) and (10). The feeler (2) is then brought to bear on the thread (1) in a position wherein two magnets (21) and (18) are not aligned and two pistons (16) and (17) are allowed to close the outlets (9) and (10) by gravity. The pistons (16) and (17) may be loaded to the closed position by springs.</p> |
