| 摘要 |
641,409. Wheel tyre air tubes. UNITED STATES RUBBER CO. Sept. 22, 1948, No. 24759. Convention date, Dec. 31, 1947. [Class 144 (ii)] A pneumatic tyre inner tube 1 of rubber composition has a pair of rubber composition circumferential flaps 3, 4 vulcanized to that region of its outer wall which, when the tyre 7 is assembled on a wheel, lies within the wheel rim 8, said flaps 3, 4 being interconnected by an integral strip 5 of rubber composition forming a layer covering that part of the tube which lies opposite the central portion of the rim. The central strip 5 is more extensible than the flaps 3, 4 and to this end is made of thinner rubber, or of a more extensible composition, and may have circular or slotted perforations 6 formed therein. The flaps 3, 4 and the strip 5 together extend over 13-27 per cent of the crosssoctional perimeter of the tube. When the tyre 7 and tube 1 are assembled and inflated on a wheel (Fig. 2) the flaps 3, 4 lie adjacent the junction between the tyre beads and the rim 8, and the tube expands into the well of the rim. The strip 5, being more extensible than the flaps 3, 4, takes the whole of the stretch involved in such expansion, the flaps 3, 4 remaining unstressed and serving to protect the wall of the tube 1 from injurious chafing arising from movement of the tyre bead on the rim under working conditions. |
