A bed (20) comprises a fixed width section (52), a wing (50) movably coupled to the fixed width section, a motor assembly (110) mechanically grounded to one of the fixed width sections and the wing, and a lead screw (126) coupled to the motor assembly and to a lead screw receiver (96) nonmovably associated with the other of the fixed width section and the wing. Operation of a motor (112) is capable of moving the wing between deployed and stored positions. A retrofit kit for upgrading a host bed having manually operable width extension wings comprises a motor assembly (110), a bracket (120 or 140) for mounting the motor assembly to a bed frame, a lead screw set comprising oppositely handed lead screws (126) each attachable to the motor assembly, and a lead screw support bracket set. Each member (82) of the support bracket set is securable to a width extension wing (50) of the host bed and have oppositely handed lead screw receivers (96).
