Problem
A “crocodile shear” cuts metal to length by means of a heavy lower fixed blade (or anvil) against which an upper hinged blade continuously operates in a scissor action. Most of the machines have a heavy steel clamp for holding the scrap metal against the lower blade. Smaller machines may not have a clamp. The scrap metal is placed under and through the clamp by the operator, then pushed between the two blades.
The top blade descends and shears off the metal into sections for reprocessing. Scrap metal is usually fed by hand into the machine as an automatic feed is impracticable. This means the operator’s hands are close to the continuously moving blade and the lower blade section of the machine. These machines have caused many serious accidents to operators.
Solution
There are several recommendations for the safe operation of the machine: –
- The lower blade fitted with a fixed extension on the edge away from the moving top blade (see diagram) extended beyond the leading edge of the clamp by a minimum of 500 mm. The purpose of this fixed extension is two-fold. Firstly, it provides a firmer more stable base for the material. Secondly it removes the worker’s hands from the vicinity of the clamp and thus reduces the risk of crushing the hand against the clamp through material ‘kick up’.
- A strong rigidly-fixed mesh guard mounted around the jaws of the machine. This guard can either be fastened to the machine frame or alternatively fixed to a separate rigidly secured structure. The guard’s design needs to prevent access to the continuously acting blade at the feed side, except to the extent necessary to allow the material to be fed into the machine. The guard must be designed to minimise the risk of ‘kick-up’ entrapment between the material being cut and the lower edge of the guard. Guards need to be designed to prevent access to the jaws at both the feed and discharge sides of the machine.
- Where practicable, a chute incorporated into the guarding enclosure could be fitted to the discharge side of the machine to allow for removal of the material after shearing.
- Metal plate wider than the maximum width of the machine jaws should not be cut
- Employers must ensure a safe system of work for people operating and maintaining the crocodile shears. It is essential that operators are trained by a suitably qualified person in the hazards of these machines.
The management system needs to address the: –
- Instructions for ensuring all safety devices are in place before normal work commences and the maximum width of scrap metal which can be cut.
- Proper electrical isolation of the shears before maintenance work begins, storage of scrap prior to shearing & use of the safety devices.
- Provision and maintenance of clear unrestricted space around the machines
Hierarchy of Controls:
Engineering
Benefits
- The implementation of these recommendations offers maximum protection from accident and injury at minimal cost.
- They do not interfere with the working processes.