A cart includes a projecting load receiving platform mounted on a slide frame in turn mounted for vertical movement on a main frame. A spring mechanism urges the slide frame and platform to an elevated position so that objects may be stacked on the platform without placing them on the floor. As the weight of the stack on the platform increases the platform starts to descend until the cart is full. Conversely as items are removed from the top of the stack the platform elevates so the operator doesn't have to pick up an object from the floor. The spring mechanism uses a plurality of air springs each with a different load rating and operating in a cascading fashion. A pivoting weight operated latch holds the platform in its bottom position until released by a kick plate.