Patent attributes
A cart includes four wheel assemblies disposed on four bottom corners of a support body respectively, each wheel assembly including a hollow cylinder, a biasing member in the hollow cylinder, a roller having a partially threaded shank inserted through the biasing member and the hollow cylinder into the support body for fastening, and a threaded fastener secured to the partially threaded shank; four lock sleeves each secured onto the hollow cylinder. In a ready to wheel or wheeling state, the partially threaded shank is rested on a top of the hollow cylinder, and both the cylinder and the lock sleeve are above a bottom end of the roller. In response to a user sitting on the support body, both the hollow cylinders and the lock sleeves are pushed down with the biasing members being further compressed until both the hollow cylinders and the lock sleeves contact a supporting ground.
