| 摘要 |
PROBLEM TO BE SOLVED: To reduce the force required for the sliding movement of a swing arm and to allow a receiving table to smoothly approach to a lift point. SOLUTION: A slipoff preventive bolt is threadably attached to the upper part of a tip of a lift arm 2 and a roller 6a made of a resin and a roller shaft 7a molded from an elastic material are provided at the lower part of the tip. A roller 6b and a roller shaft 7b are provided at the upper part of the base end of a slide arm 8 sliding within the lift arm 2 and a roller 6c and a shaft 7c are provided at the lower part of the rear end. Deflection of each of the roller shafts 7a, 7b, 7c at no load is small enough so that the slide arm 8 and the lift arm 2 are freely slidable via rollers. The roller shafts 7a, 7b are deflected greatly under load and the elastic force of the slide arm 8 is adjusted so that the slide arm 8 is pressure contacted with the upper and lower surfaces of the lift arm 2.
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