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While a certain point in automation within the poultry industry has been
reached, there will always be an interaction between the product,
individual, and tools. Variability in the product will always limit the
amount of automation that can be used in certain applications. Therefore,
hand tools, individuals, and the workplace environment pose an ergonomic
challenge. The hand tool that is predominantly used in the poultry
industry is
scissors (poultry shears). High forces, repetition, and other risk factors
associated with hand tools has contributed to the high incident rate of
cumulative trauma disorders in this industry.
To address this situation, an engineering solution was developed to;
replace standard scissors, reduce risk factors associated with CTD's, and
improve workers' efficiency and product quality. The Airshirz® pneumatic
scissors allows the worker to perform a task in less time while reducing
the amount of physical exertion. Spending less effort on portions of the
job and reducing the amount of time to do them in a win-win situation for
everyone.
FUNCTION LIKE SCISSORS
The Airshirz blades were designed to be activated and fully controlled by
the finger loop. The pneumatic design gives users complete control over
cutting action and the automatic spring-return action requires no effort
to open blades.
WEIGHT
The Airshirz unit weighs approximately 1.28 pounds but is balanced on the
adductor pollicis, flexor brevis pollicis, and abductor pollicus between
the index finger and the thumb. Using the 50th percentile male hand, this
weight is balanced on 13.48 square inches of the hand.
Surface contact with conventional
scissors
Surface contact with Airshirz
PRESSURE POINTS
Some areas of the body are more sensitive than others because tendons,
nerves, and blood vessels are located close to surface and underlying
bones; sides of fingers, back of fingers, palm and fingers. The points in
the figure below show where the fingers come in contact with conventional
scissors.
The surfaces of the Airshirz unit are smooth and the finger loop allows
all fingers to come in contact with its surface. Another benefit is that
the thumb is not used to operate the Airshirz. The design of the Airshirz
unit allows the thumb to "rest" comfortably in a neutral
position against the side of the unit and eliminate a pressure point.
CONTACT STRESS
There is no force required to open the blades of the Airshirz. The blades
remain open and the finger loop in the extended position to eliminate the
added pressure of opening blades as with conventional scissors.
REDUCE PHYSICAL DEMANDS
A pilot study conducted with several medical doctors incorporated
electromyography and a Jamar grip strength dynamometer to identify the
benefits of using the Airshirz instead of conventional scissors. The pilot
study was performed at a work rehabilitation center and used non-poultry
workers as volunteer subjects. Figures A and B below depict the results of
this study. You may request a copy of the full study by
sending you name, address, and phone number to
sales@bettcher.com.
Figure A.) Muscle Activity (EMG)
Figure B.) Peak Grip Strength (Force)
CONCLUSION
In the case of the Airshirz, a need for an improved type of scissors was
identified in the poultry industry. The conventional scissors had been
associated with CTD's of the hands and wrists. Five criteria were
established for the Airshirz unit.
1. Function like scissors
2. Incorporate sound ergonomic principles
3. Reduce physical demands
4. Improve efficiency
5. Improve psychophysical interaction
Through a series of medical, engineering, and psychophysical tests, all
five criteria were met with fascinating results. The final product met the
demands of the customers and more importantly, provided a solution to the
Cumulative Trauma Disorders associated with conventional hand scissors.
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