A clutch mechanism for use with a carrier of a linear drive device includes a housing, a first gear, and a first clutch arrangement. The first gear coupled to the housing and has gear teeth to engage a threaded shaft of a linear drive device . Rotation of the shaft causes the housing to move along the shaft in a first mode of operation. The first clutch arrangement prevents substantial rotation of the first gear. The first gear permits rotation of the first gear with respect to the housing. The housing can be manually moved along a length of the shaft, in a second mode of operation, by exerting a force on the housing. The rotational force applied to the first gear through the interaction of the threaded shaft and the gear teeth exceeds the first threshold.
