STRING

摘要

PROBLEM TO BE SOLVED: To reduce weight, and prevent a stepping squeak after execution work by supporting end parts of step boards for stairs by a shape steel material having a side plate part, an upper plate part and a lower plate part connected to the side plate part, and arranging receiving seats to install the end parts of the step boards for the respective stairs on the side plate part. SOLUTION: An open string is made of a shape steel material having a side plate part 11, an upper plate part 12 and a lower plate part 13 to which upper and lower parts of the side plate part 11 are integrally and continuously connected and lip parts 14 and 15 by bending tip parts of the upper and lower plate parts 12 and 13 to the inside. In this case, a printing decorative sheet 00a is stuck to a surface of the shape steel material, and installing holes 16 are bored in the side plate part 11 by press working. Receiving seats 17 are formed by bending end parts of battens of the installing holes 16 in the horizontal direction in a condition of being continuously connected to the lower sides of the installing holes 16. Next, in end parts of step boards for stairs, the step boards are fixed by machine screws from below the receiving seats 17, and the step boards for stairs are firmly fixed to the receiving seats 17. Therefore, weight is reduced by the shape steel material, and transport and execution work are facilitated, and a stepping squeak generated by rubbing of mutual fibers after the step boards for stairs are installed, can be prevented.