| 摘要 |
<p>Valve means 1 for controlling vacuum lifting apparatus 2 comprising a bellows like lift tube 3 having an interior 6 connectable to a vacuum generating means, with a suction foot 10 associated with the lift tube 4. Valve means 1, serving to connect the interior 6 at a controllable level to atmosphere to regulate the vacuum therein and hence the axial extension of the lift tube 3, comprises a housing 11 having a first connection 12 to the suction foot 10 in air-flow communication with a first chamber 13 of the housing 11, which chamber 13 has an outlet 14 to atmosphere controlled by a first valve member 15. A second connector 18 is in air flow communication to a source of vacuum via the lift tube 3, and air flow along the second connector 18 is controlled by a second valve member 20, whereby, in a load gripping and lifting mode, the first valve member 15 is partially open and the second valve member 20 is fully open; and in a load-releasing mode where the first valve member 15 is further or fully opened to admit air to the suction foot 10 and simultaneously, or shortly thereafter, the second valve member 20 is closed, or partially closed, producing a higher vacuum in the interior 6.</p> |
