| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method for expanding/contracting an expansion body by which such work can be carried out easily from the ground surface such that a rack tool connected with a rope can be hooked on a suspended overhead wire for taking a safety measure, when a worker conducts work on a pole for conducting telephone line installing work, etc. SOLUTION: An expansion rod device A is provided with an expansion body 2 equipped with a housing base body 1 and four nested members 20, 21, 22, and 23 and a screw rod 3 which is inserted into the expansion body 2, rotated in the normal and reverse directions by means of a drive motor M, and has a required length. The nested members 20-23 of the expansion body 2 have long nuts 25, which are engaged with the thread section 32 of the rod 3. When the rod 3 is rotated in the normal direction, the expansion body 2 is elongated, because the thread section 32 of the rod 3 is moved in a state, where the section 32 is successively engaged with the long nuts 25 of the nested members 20-23 from the member 23 having the smallest diameter. When the rod 3 is rotated in the reverse direction, the expansion body 2 is contracted, because the tread section 32 is moved in a state, where the section 32 is successively engaged with the nuts 25 of the members 20-23 from the member 20 having the largest diameter. The coupling and decoupling of the members 2-23 re performed by means of locking devices 4, when the expansion body 2 is elongated and contracted.</p> |
