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Hand Tools
There are others as listed below:
- Repetition: The number of repetitive work movements made per work session
- Force: The exertion needed to do the job i.e. grip force or finger pressure
- Posture: which awkward positions do you need to get into to achieve the job and for how long.
- Direct Pressure on Palm: any pressure on the palm or carpel tunnel.
- Vibration: what exposure is there to vibrating tools or equipment
- Temperature: exposure to extremes of temperature
The more factors involved, the greater the possibility of developing cumulative trauma, although not all employees exposed to these factors will be affected. Hence the use of the term RISK. The triggers of a disorder are still undergoing research, as the precise measurement of these factors is often difficult.
Trauma builds up and commonly effects hands and wrists, not only because of the tasks involved but because of a built in weakness. The arms and shoulders are also at risk as is the back.
There are a number of ways to help prevent injury brought about by the main risk factors.
The equipment design should aim to keep the hand/wrist in neutral position with arms low and elbows in whilst decreasing the exertion needing to carry out the job. The number of motions needs to be lessened or at least smoothed. The equipment needs to eliminate pressure or provide cushioning. The hand needs to be isolated from tool vibration and extremes of temperature.
Sometimes dedicated tools are best for the job as they better meet the ergonomic requirements and lead to efficiencies.
Some situations are described below.
SCREWDRIVERS
Employees who use manual screwdrivers routinely could be at risk of cumulative trauma. Power screwdrivers can reduce many of the risks even though it adds one of vibration and torque shock.
MANUAL SCREWDRIVER
- Repetition
- Bent wrist
- Pressure on palm
- Exertion
POWERED SCREWDRIVER
Repetition and exertion carried out for employee. Grips are usually flexible allowing for a neutral positioned wrist. Better grip reduces pressure on palm.
The additional problems of
- torque shock can be overcome by providing tools with internal torque control, or by fixing the tool or by providing torque absorbing bars.
- trigger finger can be alleviated by using easy operating tools
PACKAGING
Work stations should be set up to eliminate unnecessary hand and arm movements. Rather than an employee picking up items off production line and placing them into a box is it possible to slide the products off the end of the line straight into the box. The employees should not need to work with a bent wrist.
Use fixtures or jigs to hold products, parts or tools. And design tools to allow the use of a power grip rather than a pinch grip.
TOOL GRIPS
- Two handed tools distribute the exertion and provide better control.
- Tools should fit both left and right handed workers
- Your thumb and index finger should slightly overlap around a closed grip for maximum strength.
- A tool grip should not be so large that it is difficult to hold or grip
- Neither should it be so small that you strain to hold it.
- For tolls that open and close, a spring which returns the handle to the open position is often a good idea.
- A soft covering on the tool handle should be provided reducing edges and pressure points, vibration and slipperiness and protecting from hot and cold.
- Braces and supports to hold the tool or the product.
WHAT TO DO AS AN EMPLOYER
- Job Enlargement
- Rotate the jobs
- Cross train in the workplace
- Increase the number of short breaks
- Evaluate easiest method of doing the job
- Reduce workload
- Encourage Exercise
