Abstract: A connection mechanism (4) comprises first and second components (6, 8) which can be selectively coupled together, one of the first or second components comprises a locking member (25) which is moveable between a first state and a second state, the other of the first or second component comprises means (16) for initially moving the locking member from the first to the second state as the first and second components are initially drawn together and means (19) for returning the locking member to the first state once the first and second components are fully engaged together to prevent disengagement of the first and second components.