Automatic safe load indicator

An automatic safe load indicator that warns, either visually or audibly, that the load is approaching the maximum safe level or that it has exceeded that value. 

Safe working load indicators. This can vary from a simple notice of SWL s and pendulum type load/radius indicators on the jib, through to a dynamometer incorporating a load cell on the jib with a display readout in the operator s cab, to sophisticated microprocessors incorporating automatic safe load indication and overload alarms. The competent person must satisfy himself that the type of safe load indicator fitted conforms to the relevant statutory requirements, and that the indicator is accurate for the configuration of the crane rigging. 

All lifting equipment must be examined regularly (Regs. 10, 28, 34, 46) with safe means of access provided for those carrying out the inspection (Reg. 17). The safe working load must be clearly indicated (Regs. 29, 45) and jib cranes must have an automatic safe load indicator (Reg. 30) which must be tested. The specified safe working load must not be exceeded (Reg. 31). 

All cranes with a lifting capacity in excess of 1 ton must be fitted with an approved type of automatic safe load indicator (Construction (Lifting Operations) Regulations 1961). 

If the crane has a capacity of more than 1 tonne, does it have an automatic safe load indicator that is maintained and inspected weekly ... 

Automatic safe load indicators must be fitted to all cranes and it is the responsibility of the operator to ... 

Each overhead electric hoist must be equipped with a limit device to stop the hook at its highest and lowest point of safe travel. Each hoist must automatically stop and hold any load up to 125 percent of its rated load if its actuating force is removed. The rated load of each hoist must be legibly marked and visible to the operator. Stops must be provided at the safe limits of travel for a trolley hoist. The controls of each hoist should be plainly marked to indicate the direction of travel or motion. 

Control systems generally contain many automatic protection and alarm systems. A typical protection system includes a main stop valve which is spring-loaded to close and is mounted ahead of the turbine inlet valve. Hydrauhc oil keeps this valve open if several protection devices all indicate safe operation. These include an overspeed governor, bearing oil pressure relay, a manual trip relay, and where apphcable, a low-vacuum relay and nonreturn valve relays. 

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