Patent ID: 7152848

Claim:
An extensible leg assembly, comprising: a first leg member; a second leg member interconnected with the first leg member for relative axial movement; a rotating shaft having threads thereon; a threaded member threadably engaging the rotating shaft and transmitting thrust forces between the second leg member and the rotating shaft; and an axial thrust bearing for receiving thrust loads along the axis of a rotating shaft, the thrust bearing comprising: a first bearing member having a race formed therein; a second bearing member having a race formed therein at an inner side of the second bearing member; at least one roller member received in the races of the first and second bearing members for permitting relative rotating motion of the first and second bearing members about a rotational axis defined by the axial thrust bearing, and wherein the second bearing member has a bore therethrough defining a first inner diameter, and a surface adjacent an outer side of the second bearing member defining a second diameter that is larger than the first diameter, the second bearing member further including an annular bearing shoulder extending between the bore and the cylindrical surface, the bearing shoulder engaging the rotating shaft to transmit axial forces between the shaft and the thrust bearing.