| 摘要 |
A vehicle's spare tire can be made lighter and cheaper for economy, but this entails limited performance and shorter safe life. The invention provides a temporary spare tire with a tread which emits a distinctive two-tone or three-tone warning sound when in use to give audible warning of the need for early replacement. The tread is structured to maximize highway noise, and is circumferentially divided into two or more parts, each at least one-sixth of the circumference and which contact the highway in sequence. Each part emits a particular different note or tone, so that different notes or tones sound in sequence as the vehicle moves. The preferred tread structure is a block pattern with a sinusoidally varying land/sea ratio to concentrate acoustic energy at a characteristic frequency within each circumferential part. The same tread pattern may be used around the whole tread, "stretched" into long-pitch lengths for low notes and "compressed" into short-pitch lengths for high notes. |
