Cart with spring-loaded platform

Abstract

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.

1 . A cart comprising: 
 a base    at least one post attached to said base;    at least one spring encircling at least one of said posts; and    a platform supported by said spring,    wherein a load placed on said platform compresses said spring and said platform moves slidably along said post toward said base, and removal of all or part of said load from said platform allows said spring to expand, pushing said platform slidably along said post away from said base.    
     
     
         2 . The cart of  claim 1 , wherein said load compresses stacked items and said platform moves along said posts so that the uppermost item on the stack is maintained at a desired height.  
     
     
         3 . The cart of  claim 1 , comprising at least four posts.  
     
     
         4 . The cart of  claim 1 , further comprising means for removably attaching said posts to the said base.  
     
     
         5 . The cart of  claim 4 , wherein said means for removably attaching said posts to said base include pins on said base over which the posts are placed.  
     
     
         6 . The cart of  claim 4 , wherein said means for removably attaching said post to said base include pockets in said base for receiving said posts.  
     
     
         7 . The cart of  claim 1 , wherein said platform comprises a platform frame which surrounds said posts.  
     
     
         8 . The cart of  claim 1 , further comprising sleeves attached to said platform to receive said posts.  
     
     
         9 . The cart of  claim 8 , wherein said sleeves have at least one bearing.  
     
     
         10 . The cart of  claim 1 , wherein said sleeves have at least two bearings.  
     
     
         11 . The cart of  claim 1 , wherein said posts are square.