HATCH COVER Russian patent published in 2009 - IPC E02D29/14 

FIELD: construction.

SUBSTANCE: hatch cover consists of an upper plate and additional lower locking plate and screws coupling that pull both plates towards each other when cover is operated. Screw coupling screw is hollow and located in the upper plate hole in rigid connection with the plate. The screw coupling nut is coupled with locking plate and installed in the locking plate hole so that it can move in axial direction, be screwed and unscrewed, rotate around screw and be fixed in locking plate hole in working position of screw coupling. The upper nut end is provided with holding lock to prevent axial displacement in locking plate hole in inactive position of screw coupling. The lower nut end is provided with a key mechanism to turn nut around coupling axis. The nut holding mechanism preventing its axial displacement in the locking plate is implemented with a nut-connected ring, whereby the nut rests upon the locking plate freely when screw coupling is inactive. The key turning mechanism is represented with a set of holes being located opposite to each other along the nut wall in longitudinal direction and in its lower part located under the locking plate. There is a flange in the lower part of nut, which contacts with the lower surface of locking plate in the cover working position.

EFFECT: reliable cover holding in well hatch and reliable cover operation excluding unauthorised access to well.

3 cl, 6 dwg