What are the ergonomic concerns for selecting powered hand tools?
- context Select tools that can be used without bending the wrist. Hand tools should allow the operator to grasp, hold, and use the tool with the wrist held straight.
- context Select the tool with the workplace layout and job design in mind. Sometimes a tool is correct for one operation and incorrect for another.
- context Use the right tool for the job. Ensure it is the right size and has sufficient power to do the job safely.
- context Weight of the tool and distribution of the load affect the way the user holds the tool. Limit the weight of the tool to 1.4 kg (3 lbs) or less for tools operated with one hand. For precision operations, tools should weigh less than 0.5 kg (1 lb). When there is a choice, select a tool of a low-weight.
- context When the weight of a tool cannot be reduced, use a tool balancer.
- context Select low-vibrating tools.
- context Choose tools with vibration-absorbing handles, like those covered with cork, rubber, plastic or plastic bonded to steel, to reduce hand-arm vibration.
- context Choose hand tools that have the centre of gravity within or close to the handle, or that help line up the tool’s centre of gravity with the gripping hand.
- context Choose the tools with handles that can be held using a power grip. A power grip allows the operator to align the fingers such that they work with, rather than against, each other to maximize the grip.
- context Select tools with rounded, cylindrical, or oval shape, and smooth handles that you can grip easily.
- context Choose handles that extend at least the same length as the palm of the hand to prevent pressure points in the middle of the palm. Where possible, the handle length should be 14 cm (5.5 inches) with a minimum of 10 cm (4 inches). A longer handle length may be required if work is performed wearing gloves.
- context If they are available, choose hand tools with double handles to permit easier holding and better manipulation of the tool.
- context Select tools with a trigger strip, rather than a trigger button. This strip will allow you to exert more force over a greater area of the hand that, in turn, will reduce muscle fatigue. Triggers should be larger than 2.5 cm (1 in) so that more than one finger can be used.
- context Ensure that the trigger works easily to reduce the effort needed to operate it.
- context Select hand tools that encourage a good grip, such as non-slip, non-conductive and compressible materials like plastics or compound rubbers. The goal is to reduce the effort needed to use the tool effectively and at the same time, prevent the tool from slipping out of the hand.