钢箍的“闭锁形后弯”作法(图1),以前是应用杠杆的方法来进行后弯,并有手动的、利用油压的等等弯筋机具。这些弯筋机具的主要缺点是弯曲箍筋后会使角部主筋产生向柱梁内部位移(图2),特别是当象图1那样的斜撑筋,由于要弯曲145°以上,主筋位移更大,这就造成了与柱梁断面设计计算的情况不一致,并且主筋的强度愈高, The “closed-back bend” method for steel hoops (Fig. 1) was previously used to perform backbends using a lever method, and has manual, hydraulic bending, etc. bent bar machines. The main drawback of these bending machine tools is that after the stirrups are bent, the main bars of the corners will be displaced to the inside of the column beams (Figure 2). Especially when the bar supports are bent like 145, the main bars are displaced more than 145°. Large, which results in inconsistent calculations with the column beam design calculations, and the higher the strength of the main reinforcement,