| 摘要 |
A vacuum disk includes a hollow base having an open leading end adapted to engage a flat support surface. The hollow base and the support surface define a vacuum space when the hollow base abuts the support surface. A gasket formed of styrene block copolymers forms an airtight seal around the vacuum space. A hub formed integrally with the base defines an airflow passageway through which air in the vacuum space may flow. A valve is seated within the airflow passageway. A hollow cylinder has a leading end that sealingly engages the hub and a piston head is slideably positioned within the hollow cylinder. A vacuum is created in the vacuum space by abrupt withdrawal of the piston head from the hollow interior of the cylinder. Ambient air rushing into the hollow interior of the cylinder abruptly closes the valve before the vacuum is lost.
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