1. the pressure relief valve in the hydraulic system: inhibits the abnormal high pressure in the circuit to prevent damage to the hydraulic pump and motor and to prevent overload.
2. safety devices for crane luffing: when the accident happened, jib luffing cylinder circuit of high pressure hoses or tubing burst or switched off, the hydraulic circuit balancing valves work, locking cylinder work of inferior oil, prevents the boom from falling, so as to ensure the safety of work.
3. safety devices for crane scale: when the accident happened, crane telescopic cylinder circuit of high pressure hoses or tubing burst or switched off, the hydraulic circuit balancing valves work, locking cylinder work of inferior oil, Hung goes back on its own, so as to ensure the safety of work.
4. a high limit device: after you hook up to a specified height, touch a weight limit, opening limit switch, "around the" indicator light is on, and cut off the hook lift, boom out, hanging arm volts to move operations and ensure safety. Just manipulate the hook down, boom retracted or the arm lifted (that is, the security operation), handle, weight limit lifted constraints, operations returned to normal. On special occasions, if still need to trace around the operation, press the release button on the instrument box, limited role of disarmament, but must exercise great caution of actions to prevent accidents.
5. leg lock mechanism: when the accident occurred, leading to the leg vertical cylinder of high pressure hoses or tubing when broken or cut, hydraulic system for bidirectional hydraulic lock can block legs in blocked cylinder two-chamber pressure oil, leg does not shrink or thrown out, so as to ensure that the safety of crane operations.