工业与民用建筑现浇钢筋混凝土楼板常需预留一些大小不一的管道孔洞。常规做法是小孔用木塞,大孔制做圆形木盒。特别是以钢模代替木模以来,木塞或木模具很难准确地固定在钢模板上。针对上述问题,我们采用铁皮制做变径筒模具代替传统木模具。这一改进,深受工人同志们的欢迎。此模具筒主要优点如下:①同一模具可适应大小不同的孔 Industrial and civil buildings cast-in-place reinforced concrete slabs often need to reserve a number of pipe holes of different sizes. The conventional practice is to use a wooden stopper for the small hole and a round wooden box for the large hole. In particular, since the steel mold is used instead of the wood mold, it is difficult for the cork or wood mold to be accurately fixed on the steel mold. In response to the above problems, we use the tin plate to make the adjustable-diameter barrel mold instead of the traditional wood mold. This improvement has been welcomed by the workers’ comrades. The main advantages of this mold cartridge are as follows: 1 The same mold can accommodate different sizes of holes