Expelling mechanism for discharge tubes and drain tubes of submarines

Claim 1

An expelling mechanism adapted for use with discharge tubes and drain tubes of submarines for ejecting a weapon by means of compressed air, comprising in combination a chamber formed with an outlet opening, and being adapted to substantially communicate selectively with a storage container holding compressed gas, a discharge valve movable towards said opening in a closing direction, and away therefrom in an opening direction at a selectable opening velocity, hydraulic control means for controlling the movement of said discharge valve including a cylinder adapted to be filled with hydraulic fluid, a piston reciprocally movable along a stroke within said cylinder along said opening and closing directions, respectively, and partitioning said cylinder into two cylinder chambers, overflow means operable during each of said directions, and establishing communication between said cylinder chambers, and connecting means connecting said discharge valve with said hydraulic control means, said outlet opening and said overflow means having cross-sections variable in dependence of said stroke, respectively, so that the outlet opening increases as the discharge valve moves in the opening direction, the opening velocity of said discharge valve is controllable, and different respective cross-sections of said overflow means operable during each of said directions are settable in dependence of said stroke, irrespective of whether the piston moves in an opening direction on in a closing direction.