A bed comprises a fixed width deck section (52), a wing (50) movably coupled to the fixed width section(52), a leadscrew (126) having a rotational axis, a leadscrew driver coupled to the leadscrew for rotating the leadscrew about its axis, and a release unit. The release unit is coupled to the wing (50) and configured to move between a) an engaged position in which the release unit engages the lead screw (126) and moves therealong as the leadscrew rotates about the rotational axis thereby causing the wing (50) to translate relative to the fixed width section (52)； and b) a disengaged position in which the release unit is disengaged from the leadscrew (126)
