| 摘要 |
PROBLEM TO BE SOLVED: To provide an inner frame at a low cost by integrally forming the whole of one stainless plate in the inner frame. SOLUTION: An inspection-hole structure is composed of a planar shaped rectangular stainless outer frame 1 and a planar shaped rectangular stainless inner frame 4 set into the outer frame 1. The outer frame 1 has an upstanding plate section 5 surrounding the periphery of the inner frame 4 and a plate section 8 which is continuously connected at the lower end of the upstanding plate section 5, being protruded horizontally to the inside and receiving the inner frame 4, and the inner frame 4 is drawn by a press, using one stainless plate as a material, and plate sections 12 positioned on four each side section are erected toward the vertical direction and side plate section are formed. The mutual adjacent sections of the plate sections 12 as the side plate sections are manufactured by superposing connecting pieces 15 connected continuously at one ends of adjacent one plate sections 12 to internal surfaces at one ends of the other plate sections in a state, in which the connecting pieces 15 are bent at right angels, and spot welding the connecting pieces, and the inside of the inner frame 4 is filled with mortar.
|
