| 摘要 |
The method includes three steps. In the first step a zinc- plated steel plate is bent into a supporting bar in shape of a channel, and holes for crossing bars are punched on the side (3) of the supporting bar in equel spacings. In the second step the crossing rod made of zinc-plated steel pipe is hemmed in a die. As a result projections are formed at the slightly inner part of both ends of the crossing rod. In the last step the rod are inserted between a pair of the supporting bars facing each other in parallel, and the projected part of the rods out of the holes are bent by a pressing die.
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