| 摘要 |
1,179,004. Blow-moulding; burr prevention. DR. ING. FROHN - PLASTIC G.m.b.H. KUNSTOFFWERK. 25 May, 1967 [26 May, 1966], No. 24302/67. Heading B5A. An extrusion blow moulding machine wherein the mould 14 has an opening comprising a cylindrical portion 24 leading into a wider portion 16 of the mould and a conical entry portion 26 and the blowing mandrel 20 has a blowing nozzle 30 at its leading end separated by a shoulder 50 from a cylindrical portion 32 of larger diameter which slidably fits the cylindrical portion 24 of the mould, is operated so that the mandrel 20 is advanced to shear off a surplus part 40 of the tube against the sharp edge 44 between conical entry portion 26 and cylindrical portion 24, the mandrel then being further advanced so that the leading end of portion 32 projects from the inner end of the cylindrical portion 24 into the wider portion 16 of the mould so as to form an internal annular recess in the inner edge of the upper end of the tube. The mandrel may have pointed stop members 36 mounted on a portion 34 of larger diameter than the entry opening 26. |
