Abstract: A telescoping mast has a plurality of elongate tubular sections which are telescopically attached to each other and an axial drive screw centrally located in the mast for extending and retracting the elongate tubular section. A gear assembly is connected to the drive screw for rotating the drive screw. A nut carrier assembly is secured to tubular sections. Each nut carrier assembly has a threaded nut housed within a nut carrier. The threaded nut engages corresponding threads on the drive screw. A locking mechanism is provided for locking the gear assembly which has a first section surrounding a second section secured to the gear assembly. The second section has an elongated member extending from a surface of the second section. The first section has at least one slot for engaging the elongated member, thereby preventing rotation of the gear assembly.

Abstract: A rigid support bearing for a rotating shaft has bearings arranged concentrically around the shaft instead of spaced axially and is used in a screw drive telescoping mast assembly. An axial drive screw is centrally located in the mast assembly for extending and retracting the tubular sections. A lower bearing assembly supports the drive screw and uses the concentric bearing arrangement to reduce the nested height of the mast.