Ergonomics
10/05/2012 - 11:26 PM
Ergonomics
The rising importance of Ergonomics... to worker, factory and country
Ergonomics (literally, the science of work) is the key to designing a better workplace - situations where tool, task, and tool user come together with a minimum of stress.
A minimum of stress on the worked leads to a maximum level of quality production.
It simply makes good sense.
When a tool is well balanced and fits the user's hand; when the workpiece is at a comfortable height and can be reached without awkward stretching, quality production follows naturally.
Unfortunately, all too often the worker is expected to adjust to the needs of the assembly line. Tools must be used out of full view, fasteners must be driven with arm overhead and wrist twisted - or the working environment is noisy, ill-lit, too hot or too cold.
In less than optimum conditions, quality and productivity decline, morale suffers and sick calls and absenteeism rise.
Considerations when choosing a Hand Tool
A potential source of Cumulative Trauma Disorders are hand tools that are improperly selected for the task and the user. Here are just some of the factors that need to be considered:
+ Weight - is the tool too heavy?
+ Optimum use of balancers to offset weight.
+ Balance - front to rear, side to side.
+ Fit to hand.
+ Neutral wrist position during operation.
+ Trigger size, type and placement.
+ Force required for trigger operation.
+ Slip resistance.
+ Grip length.
+ Accommodation for both hands.
+ Elimination of sharp edges and corners.
WRIST POSITIONS
1. A tool suspended from a properly adjusted balancer is:
- Within easy reach, minimising muscle strain.
- Parallel to the hand, preventing deviation of the wrist.
- Nearly weightless, requiring little effort for movement.
Incorrect: Poorly positioned or improperly adjusted balancers may actually hinder the operators they are intended to help. Improperly balanced tools require wrist deviation during operation, compressing the carpal tunnel.
2. Operator tasks should be performed with assemblies positioned directly in front of the operator, and within a comfortable reach.
Incorrect: Reaching ahead to perform operations early on a moving assembly line places added stress on the wrist, arm and shoulder muscles. Ulnar deviation (bending the wrist toward the little finger) compresses the median nerve and tendons which run through the carpal tunnel.
3. The use of an angle configuration tool allows the operator to maintain a neutral wrist position, minimizing compression of the carpal tunnel.
Incorrect: The use of a pistol grip tool in this application results in "flexion" (bending of the wrist toward the palm), compressing the median nerve and tendons which run through the carpal tunnel.