摘要 |
The inwardly facing portions of annular springs adjacent the inner edge thereof are formed into two or more regions of predetermined angular or curved slopes and radial extent. When the peak of a shaft cam passes an annular set of ball bearings between the springs, the loaded springs unload at a rate determined by each region slope and the radial extent of the regions to consecutively drive the shaft at corresponding rates and forces. To precisely obtain the desired spring characteristics, a composite spring can be used formed from a steel spring sandwiched together with a plastic member (e.g., nylon).
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