A method for the production of cyclic 4 - halogenpregnan - 3, 20 - dione - 3, 20 - dike line

摘要

724,495. Retreading tyres. SUPER MOLD CORPORATION. June 22, 1953 [Aug. 16, 1952], No. 17263/53. Class 87 (2). A tread-centering device for a tyre retreading mould comprises axially movable pressure rings 17 having annular rings 19 for the engagement of tyre treads 18 on tyre 8 in mould 1. The rings 17 are operated by fluid pressure in cylinders 25, the fluid pressure being controlled by valve 46, Fig. 4. In operation the mould-parts 2 and 3 are separated and the tyre 8 with air-bag 13 and curing rim 14 inserted in part 3, after which the rings 17 are advanced and the mould closed so that rings 17 engage corresponding tyre beads 18 and move them to the dotted-line position of Fig. 1. The air bag 13 is inflated and the tyre 8 assumes the full-line position of Fig. 1. The rings 17 are retarded when the tyre tread 33 has obtained an initial vulcanization set or in some' cases at the end of vulcanization. The pressure rings 17 are again advanced on deflation of the air-bag to facilitate removal of the tyre. The valve 15 of the air bag is saved from damage by notches 48 aligned on rings 17.