| 主权项 |
1. A telescoping mast assembly, comprising:
at least two elongate tubular sections, wherein a second elongate tubular section is telescopically received by a first elongate tubular section; a rotating shaft centrally located in said mast assembly for extending and retracting said second elongate tubular section; and, a lower support assembly configured for supporting a lower portion of said rotating shaft, said lower support comprises a first inner bearing assembly and a second outer bearing assembly arranged horizontally and concentrically about said rotating shaft; wherein said first inner bearing assembly comprises a ball bearing housing comprising ball bearings which is positioned within a substantially concave opening of a ball bearing housing comprising ball bearings of said second outer bearing assembly and said first inner bearing assembly is positioned within said second outer bearing assembly; such that said second outer bearing assembly housing comprises a single portion that both surrounds and covers adjacent to at least upper and side ends of said first inner bearing assembly housing and wherein said second outer bearing assembly is concentric with said first inner bearing assembly and said second outer bearing assembly is positioned radially outwardly from said first bearing assembly in a horizontal direction wherein said ball bearings of said inner bearing assembly all lie in a first horizontal plane extending through of a centerline of said ball bearings of said inner bearing assembly located above a second horizontal plane extending through a centerline of said ball bearings of said outer bearing assembly, wherein said ball bearings of said outer bearing assembly all lie in said second horizontal plane and wherein said second outer bearing assembly housing and said first inner bearing assembly housing do not move in a longitudinal direction along a longitudinal axis of said rotating shaft. |
