| 摘要 |
1,069,282. Ventilating shelters. M. VON LINSINGEN, [trading as BOCHUMER EISENHUTTE HEITZMANN & CO.], H. TEVES, E. A. TEVES, and M. TAUSEND. April 8, 1964 [April 9, 1963], No. 14533/64. Heading F4V. [Also in Division F2] A self closing cover-plate for ventilating shafts of shelters, of the kind which is lifted from a closed position to an open position by means of a piston type guide rod 3 and pressure operated cylinder 6, and which falls under gravity from its open position to a pre-sealing position with compressed air formed in the cylinder 6 forming clamping means to slow the fall of the cover in the pre-sealing zone, wherein locking members 14 operated by an hydraulic pressure medium symmetrically engage the guide rod in the open and closed positions of the cover and frictionally lock the guide rod in the open position of the cover. The guide rod is narrower at the upper end to form a shoulder 3a co-operating with the locking means in the closed position to keep the cover closed in the presence of reduced pressure outside the shelter or increased pressure inside. The locking members, in the form of three rods having end faces of corresponding shape to the guide rod, are operated by two telescoping pistons (Fig. 3, not shown), an inner small piston (18) serving to extend the locking members to lock the guide rod in the closed position, and an outer large piston (17), limited in movement, serving to apply a larger force to the locking members to maintain the guide rod stationary in the open position of the cover-plate. The cover seating frame 8 rests on a plurality of supporting members 7, and consists of a sectional east-steel ring 8a forming a downwardly tapering seat, and is externally braced by ribs 8b. The lower flange of the ring is provided with a rubber-asbestos packing ring on which the cover-plate rests in its closed position. |
