| 摘要 |
Flat rate spring (60) operating beyond the elastic limit of the material of which it is constructed. The spring (60) includes a length of resilient material having terminal end portions (62,63) and a central body portion (61). The terminal end portions (62, 63) are adapted for respective connections to a first member (50A) and a second member (52A). Each terminal end portion comprises a convoluted portion of the resilient material, having a central axis substantially perpendicular to the body portion (61). The convoluted portions (62,63) are dimensioned so that, upon separation of the first and second members (50A, 52A) due to a predetermined load, they uncoil and are stressed beyond the yield point of the material so that a substantially constant load placed on the convoluted portions by said separation effects further uncoiling of the convoluted portions. The spring (60) is particularly adapted to provide a bias between a ribbon take-up spool (51) and its spiked driver (52) within a typewriter ribbon cartridge. |
