| 摘要 |
<p>A cart with a spring-loaded platform presents material continually at the proper working height. The cart has a base supporting posts encased in springs. A platform rests upon the springs. The platform is at a height convenient for the worker. As materials are stacked upon the platform the springs compress and the platform moves toward the base distance equal to the height of the newly stacked item. Thus, the top of the stack remains at the height convenient for the worker. As material is removed from the stack the spring expands pushing the platform away from the base and presenting each new item in the stack at the convenient, desired height to the worker.</p> |
