Basic risk assessment example: Flail hedge cutter (tractor-mounted)

The following risk assessment is intended as a guide to the steps that a manufacturer, or designer, should take in gathering information to evaluate risks associated with a machine before it is built.

This example lists typical hazards associated with the use of a tractor-mounted flail hedge cutter and the likely source of each identified hazard. An assessment enables a manufacturer/designer decide what steps need to be taken to eliminate or minimise risks to operators and others.

Hazard Location/source Safety measures/comments
Entanglement Drive shafts (including PTO), rotating shafts of head Shaft guards, stand off guard for head, to relevant BS/CEN standard
Draw-in/trapping Belt and pulley/chain and sprocket drives (when/if present) Guard drives/run on points to relevant BS/CEN standard
Impact Machine head or arm against people or tractor Limit movement in tractor zone
Stab/puncture By ejected debris Design head to direct debris away from tractor; provide/specify guards for cab
Ejection of parts Flails Design head cowl to direct ejected flails away from tractor. breakaway head and freely rotating flails reduce flail ejection; design to prevent head touching ground
Unexpected start up When tractor starts Control levers to automatically return to neutral (either when released or when power disengaged depending on operational requirements)
Loss of stability When free standing (out of use) Design for free-standing balance; provision of supplementary stands fitted to machine
Stability loss when mounted on tractor When arm is at maximum reach Weight distribution/recommend tractor ballast weight range
Crushing Arm movement/articulation Design for adequate clearance in fully closed position
Shearing Arm movement/articulation Design adequate clearance for articulation
Break up during operation Machine structure and cutting head Selection of materials with appropriate quality assurance; design of cowl on head to contain ejected parts
Failure of control system (unexpected overrun) During stopping of hedge cutter or tractor Design hydraulic controls to fail safe; fit overrun alarm and braking system.
Cutting/severing Sharp corners etc. Design exposed parts to have smooth/rounded corners etc
High pressure fluid injection From hydraulic system Manufacture to relevant standard; route hoses to avoid chaffing; use of pressure relief valves
Noise/vibration Measure and reduce as low as practical and when risk is likely
Errors of fitting or dismounting Before or after cutting activities Design couplings for specific application; clear instruction manual
Ergonomic hazard – position of controls Operation of cutter hydraulic remote controls Allow adequate control connection flexibility to enable operator preference when locating controls
Unexpected arm movement during transport Impact against people or tractor Isolators for hydraulic controls; locking pins to hold arm in transport position
Slip/trip/fall From machine during maintenance Design for access from ground level; instruct for safe access if design not possible
Control design/marking Manufacture to relevant standard
Electric shock From contact with overhead power lines Warning signs on machine and in instruction manual (include details of machine height/reach)

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