Structural main beam: steel plate cold bending U type groove plus middle vertical rib plate combination.
结构 主梁：钢板冷弯U型槽加中幅立筋板组合。
2
One fastening is an attaching fastening, wherein, two U-shaped dovetail groove tenons in reverse directions are arranged on a U-shaped block.
三是挂接连接件，是在U形块上有方向相反的两个U形燕尾槽榫。
3
The groove adopts a closed and butted U-shaped groove (1) to be embedded in the ground surface around a trunk of the fruit tree so as to protect closely.