GB1160059A - Building Drum - Google Patents

Abstract

1,160,059. Building drum. UNIROYAL ENGLEBERT FRANCE. 16 April, 1968 [26 April, 1967], No. 17929/68. Heading B7C. A tyre-building and shaping drum comprises a radially collapsible, cylindrical middle section I and coaxial, cylindrical end sections II, III at each end thereof, and mechanisms for radially collapsing the middle section and for moving the end sections relatively towards each other telescopically with respect to the collapsed middle section. Preferably, each of the end sections is radially collapsible when in their retracted position partly surrounding the collapsed middle section. In a typical embodiment, each section consists of small and large arcuate segments arranged alternately about its circumference, and is supported upon and rotates with a shaft S provided with sleeves 1, 2 axially movable therealong. The small and large segments 26, 25 of middle section I are connected to sleeves 1, 2 by links 11-16 so arranged that relative axial movement of the sleeves causes the small segments 26 to move radially inwardly at a greater speed and to a greater extent than the large segments 25. The small and large segments 23, 23a, 24, 24a of the end sections II, III are connected to sleeves 3, 3a by linkage which ensure radial movement of the segments relative to the sleeves and which on relative axially outward movement of the sleeves causes the small segments 23, 23a to move radially inwardly at a greater speed and to a greater extent than the large segments 24, 24a. Links 17, 17a are provided to axially retract the end sections while the middle section is collapsing, and additional sleeves 4, 4a, 5, 5a, 6, 6a are provided and arranged so as to provide air chambers C, Ca, D, Da used for the radial extension and retraction of segments 23, 23a, 24, 24a. In operation, a cylindrical carcass of a radial ply tyre may be built on the drum with all its sections forming a rigid, continuous, cylindrical surface. To shape the carcass into toroidal form prior to the application thereto of breaker and tread, the middle section is collapsed and the end sections are axially retracted whilst inflating the carcass with compressed air, which may be supplied via shaft S to the interior of the building drum. After the tread has been applied, the inflation pressure is released and the end sections are radially collapsed to assist removal of the shaped tyre from the drum.