| 摘要 |
474,588. Pneumatic tyres. UNITED STATES RUBBER PRODUCTS, Inc. June 5, 1937, No. 15625. Convention date, June 13, 1936. [Class 144 (ii)] The transverse incisions 7 of a tyre tread, preferably of the kind comprising narrow circumferential ribs and grooves 6, 9, are formed with enlarged bases providing apertures 8 to prevent cracking by inward extension of the slits under load. The apertures, which may be of rounded or other sectional form, are preferably disposed slightly above the bottoms of the grooves 9.
|
