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Laboratory Ergonomics:
Modifying Your Tools |
| Certain laboratory tasks require using tools
that promote pinch grips and awkward wrist postures. A pinch grip requires
the tool to be grasped between the index finger and the thumb for precise manipulations.
When a pinch grip is used intensively and for a long duration, such as when dissecting
fruit flies, worms and plant specimens, fatigue may occur in the hand and forearm
muscles. Over a period of time, this may contribute to developing a repetitive
strain injury. Many hand tools can easily be modified to minimize awkward wrist
postures and reduce grip and pinch force. The basic principle of a modification
is to: - Build up the part of the tool that your hand holds so
it will fit your hand better and reduce pinch force or
- Change the angle
of the handle so your hand holds the tool with a straight wrist.
- Use non-slip
materials to reduce the force needed to hold the tool in position.
The
illustrations in this section are examples of some successful tool modifications
that are used in laboratories on the Berkeley campus. If your hand tools are not
illustrated, the concepts may still apply. Be creative! |  |
Enlarge a
dissecting needle tool to
reduce pinch grip force
Purchase round cylindrical foam.
Cut the foam along one side and slide it over the syringe or glass tube to help
enlarge the grip. | 
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| Enlarging Forceps |
 |  |
| To modify the forceps,
purchase rectangular cylindrical foam.
Partially cut the foam along both sides so the forceps can be placed inside. |
 |  |
| Another way to modify
the forceps is to cut a wine cork in half and then take one of the cut sections
and cut it in half the long way. Glue the two halves to the outside of the forceps
to enlarge your grip. |
| Add a Handle |
 |  |
| with handle added | with
handle added | |
Adding a handle to maneuver a rectangular object, such as a CO2 pad, can
reduce using awkward and forceful hand postures.
To make a handle modification,
attach the rectangular object (CO2 pad) to a 1/8-inch thick piece of plastic with
Velcro (place the Velcro underneath the CO2 pad so it can be connected to the
top of the plastic). Plastic can be custom-cut at Tap Plastics in El Cerrito (525-3508).
When measuring for the plastic, allow an additional 3-inches in length
to attach the handle. A handle such as a knob, foam, cable clamp or T pipe molding
can be attached to the outer 3-inches of the plastic piece with rubber cement.
Make sure the handle will encourage using a neutral hand posture with a minimal
amount of gripping force.
|
| Add a Handle |
| |
| with handle added | with
handle added | |
Adding a handle to maneuver a rectangular object, such as a CO2 pad, can
reduce using awkward and forceful hand postures.
To make a handle modification,
attach the rectangular object (CO2 pad) to a 1/8-inch thick piece of plastic with
Velcro (place the Velcro underneath the CO2 pad so it can be connected to the
top of the plastic). Plastic can be custom-cut at Tap Plastics in El Cerrito (525-3508).
When measuring for the plastic, allow an additional 3-inches in length
to attach the handle. A handle such as a knob, foam, cable clamp or T pipe molding
can be attached to the outer 3-inches of the plastic piece with rubber cement.
Make sure the handle will encourage using a neutral hand posture with a minimal
amount of gripping force.
|
 |  |
| Unsafe
The
photo above shows how the fingers and thumb of the left hand are using an awkward
and forceful posture to maneuver the CO2 pad in a fly lab.
|
Recommended
Here, the left hand is
using a less stressful posture because the fingers and thumb are holding a knob
that has been attached to a piece of plastic. |
Alternative Handles
Creating Alternative Handles for Straight Tools Can Reduce Awkward Wrist Postures |
 |  |
| Above: Insert the
end of a paintbrush or feather into Plastizote
Tubing to create an alternative way to grip and angle the tool. |
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| Or, tape
a ¾ or 1-inch plastic cable clamp, depending on your finger size, onto
the middle of the paintbrush. Insert your index finger inside of the cable clamp
so you can more easily maneuver the brush. Plastic cable clamps can be purchased
at most hardware stores. | | |
Next: Campus Resources for Llaboratory Ergonomics
Back to Laboratory Ergonomics Table of Contents >
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