... straight cargo trolley, turntable roller skids, crawler type roller skate, steerable machine skate, veered moving roller skids, geared roller skids, and so on. ... kinds: PU wheels cargo trolley, nylon wheels roller skate, steel wheels machine skate. Machine skates can move heavy duty loads ... rotating moving dolly, nylon wheels roller skids and so on. Steerable machine skate, which have the operate bar ...