| 摘要 |
PURPOSE: A semicircular perforating device for a PVC(Polyvinyl Chloride) sash is provided to cleanly bore a hole without the residual portion by delaying the cutting finishing timing by a curved blade than a straight blade. CONSTITUTION: A semicircular perforating device for a PVC(Polyvinyl Chloride) sash comprises both operating handles, a pair of levers(130a,130b), a cutting piece(140a), and a support piece(140b). The levers have a perforated hole corresponding to the shape of a perforating blade. The front end of the perforating blade is recessed about the edge rim. Straight blades(152a,152b) and a curved blade(152f) are formed along the rim. Both vertexes(152d,152e) in which the straight blade and the curved blade are contacted are initially contacted to the material and are high points for starting the perforation. |
