The invention relates to a hoist mechanism (20) intended primarily, but not exclusively, for moving a motor driven wheelchair or scooter into and/or out of the load carrying space of a vehicle. The hoist mechanism (20) comprises a lifting arm having, at least in part, a generally U-shaped cross section, and an actuator (28). A mounting point (56) for the actuator (28) is provided within the generally U-shaped cross section. The invention also relates to a stepless adjustment system suitable for use in such a hoist mechanism (20). The adjustment system comprises an inner section (34) received within an outer section (24) in a telescoping arrangement. The outer section (24) comprises first and second body portions (44A, 44B) provided with features for engaging corresponding features (48A, 48B) provided on the inner section (34).