GB280640A - Improvements in or relating to apparatus for the manufacture of pneumatic tyre casings - Google Patents

Abstract

280,640. India Rubber, Gutta Percha & Telegraph Works Co.. Ltd., and Avery, W. L. Aug. 18, 1926. Moulding pipes and tubes and wheel tyres.-Relates to expansible tyre building drums for flat-band built tyres, and consists in the provision of spring or other resilient means to urge the expanded support to its retracted condition. As shown, the drum comprises segments B<1> embraced by a rubber &c. band A which is retained by edges B<2>, B<3>. The segments are supported by a spider C' by slotted lugs and are guided radially by pins B<6> engaging slots C<4>. Expansion of the drum is effected through thrust rods D bearing at their outer ends against abutment faces B<7> on the lugs and at their inner ends thrust faces on thrust flanges E<1>, E<2> which are mounted slidablv but non-rotatablv on a hollow shaft G<2> carrying the spider C'. The flanges E<1>, E<2> are. forced towards each other to expand the drum by levers G<3>, G<4> furnished with rollers engaging cam surfaces E', F<4> on the back of the flange E<2> and on a member F<1> connected to the flange E<1> by bolts which pass through holes in the flange E<2> and spider and prevent relative rotation. A hand lever K<1> operates the levers G<3>, G<4> through a collar L<1> pinned to a rod H<1> located within the shaft G<2> and furnished with a forked head H<2> carrying a pivot pin H<3> for the inner ends G<5>, G<6> of the levers. The cam surfaces E<7>, F<4> terminate in flat portions so that back-thrust on the rod H<1> is avoided when the drum is expanded. The shaft G<2> is rotatably supported in bearings J<3>, J<4>. The thrust rods may be positively hinged to the segments &c., and expansion may be effected through a screwed collar. A band A may be made up of longitudinally disposed wire springs. According to the Provisional Specification the thrust flanges are forced together by a screwed callar.