| 摘要 |
The drum has a retractable section (31) which can cover the end of the tire mounting surface (3) with lesser diameter, and a drum expansion system operating between two distinct expanded positions. An Independent claim is included for the corresponding method of tire making, essentially involving of wrapping a carcass reinforcement back around a rubber bead forming profile, and finishing by external application of a wire rod bead-reinforcing ring. Preferred features: A collar (31) is mounted to retract and advance longitudinally with respect to the central shaft (2) to cover the reduced-diameter end of the tire mounting surface. The expander includes a control ring concentric with the shaft, and rotatable around it. It is located axially outside the body (10) of the drum and close to one end. Expansion of the drum depends on the angular position of the control ring. The end of the body carries pegs engaging cams carried by the control ring. The ring is mounted for rotation with respect to a collar concentric with the central shaft, the latter carrying a guide cooperating with the guide peg. The control ring carries ring guides. The body is an assembly of segments formed circumferentially around the central shaft. Each segment (41, 43) carries a pin engaging in a cam carried by the control ring. |
