| 摘要 |
766,299. Tubeless tyres. GOODRICH CO., B. F. Feb. 1, 1955 [Feb. 10, 1954], No. 2949/55. Class 144 (2). To obviate ply separation in a tubeless tyre arising from air leakage through the tyre lining 10 into the crossed cord plies 11-14, the plies are vented to atmosphere by a series of punctures 25 extending through the sidewalls 18 into the plies, the punctures being formed without removal of material so that they are normally closed but open under flexure, and being circumferentially spaced around the side wall a distance equal to the cord spacing. As shown, the punctures may be formed manually or mechanically, individually, simultaneously or in groups by a single awl or needle 23, or by a gang tool, or by repeated application of a group of awls respectively. The shank of needle 23 may have a shoulder 24 to act as a depth gauge. Successive punctures 25 are radially staggered and the punctures may be positioned to extend into the turn-up of the innermost plies where they overlap the outermost plies radially outwardly of the rim flanges, Fig. 4. Additional punctures may be provided in the bases of the tread grooves 19a to extend into the crown plies, the punctures in adjacent grooves being staggered and their circumferential spacing in each groove being the product of the cord spacing and the number of punctured grooves.
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