A COUPLING MECHANISM FOR RELEASABLY INTERCONNECTING A FIRST AND A SECOND MECHANICAL MEMBER AND A LINEAR ACTUATOR EQUIPPED WITH SUCH A COUPLING MECHANISM

The invention refers to coupling mechanism and a linear actuator incorporating such a mechanism for releasably interconnecting first and second mechanical members (1, 2), longitudinally movable relative to each other, a first one of said mechanical members (1) pivotably supporting an end (F) of a first link of a knee link mechanism (3), also incorporating a second link member (3b), which first and second link members are pivotally connected to another in a knee joint (E), a control rod (4) pivotally connected to said knee joint (E), the end (D) of the second link member (3b) remote from the knee joint (E) being connected to a hook arm (5), the opposite end of which is pivotally supported at a support point (B) stationary positioned relative to said first mechanical member (1), said hook arm (5) having a hook (5a) facing said second mechanical member and being in mechanical engagement (A) with a shoulder (6, 6′) on said second mechanical member (2) as long as the said knee joint (E) is kept in a substantially stretched position by said control rod (4), which is kept stationary under influence of a holding force exerted in connection to said first mechanical member (1), but which is arranged to displace the knee joint (E), thus that the hook (5a) of the hook arm (5) is pulled out from its engagement with the shoulder on the second mechanical member, when the holding force expires or drops under a threshold value.