| 摘要 |
PROBLEM TO BE SOLVED: To prevent the generation of metallic sound at the time of expansion/ contraction by providing cushioning members at one end and the other end in the longitudinal direction of a groove part for relatively guiding a body and a sliding piece connected like an telescopic tube, or providing a cushioning member at an engaging pin. SOLUTION: A laid beam 10 is provided with a nearly cylindrical body 11; a pair of sliding pieces 12, 12 of specified length connected like an telescopic tube to the cylindrical body 11; engaging pins 14, 14 protrusively provided at the inner side face of the body 11; and groove parts 13, 13 provided at the sliding pieces 12, 12 continuously in the longitudinal direciton. Each engaging pin 14 is expandable from a position of abutting on one longitudinal end of the groove part 13 to a position of abutting on the other end. Cushioning members 19, 19 made of a synthetic resin or rubber are respectively fitted to both longitudinal ends of an elongate hole 13. The outer surface of the pin 14 can be covered with synthetic resin or rubber serving as a cushioning member.
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