... any time doesn't cut limit, refuge safetyWorking principle and basic structure:Working principle: rotating crank, power through the gear reduction ... roller and pulley drive rail hook close or unload rail.Basic structure: 1, crank 2, ratchet up to 3, big load ... and rail hook 9, sleeper sling, 10 frog slingThree, the basic parameters:1, maximum tension: 2 t2, operation force: 20 kg ...