Abstract: In a device for releasable connection of two members (2, 8) co-operating wedge surfaces (12, 17 and 13, respectively) are provided on the members. A first member (2) comprises two tightening devices (14, 16) arranged to actuate the second member (8) so that a component of the tightening force actuates the members towards each other, and another component of the tightening force actuates the wedge surfaces (12, 17 and 13, respectively) to co-operate so that also the wedge surfaces actuate the members towards each other. The device is designed for connecting the members (2, 8) in two relative positions, between which the members are rotated 180.degree. relative to each other.