Power Tool Redesign

MicroSander

A Focus on Ergonomics

Objective: Improve the ergonomics of an existing power tool.

This is the Pen Sander. A small handheld sander which uses oscillating motions and sanding bits to remove material.

While it is fairly simple mechanically, the Pen Sander is ergonomically unrefined, an ideal candidate for a redesign.

Mechanical Breakdown

Sanding Bit

Cooling Fan

On/Off Switch

Translational Arm

Electric Motor

Power Cord

Learning Through Observation

To get an idea of what could be ergonomically improved about the pen sander I decided to observe several people using it.

In order to avoid influencing the experiment, testers were given no direction in how to “correctly” hold the tool.

Key Observations:

Fingers are used only to grasp the tool, not to manipulate its position.

The wrist is used to change the position of the tool.

Every tester ended up using some form of overhand grip.

Main Take-Aways

A poorly balanced design fatigues the wrist and fingers.

The location of the power switch near the cord makes it less accessible.

The overhand grip helps dampen vibrations and balances the tool.

This is the neutral hand position.

The closer the hand remains to this position, the less fatigue there will be.

Ideation

Form factor exploration mainly catered to the overhand grip.

I modeled several handle designs and asked people to try them out while I observed.

Finalization

Rubber Grip

Finger Pad

Power Button

I decided to go with a bent handle design with rubber grips to indicate where the fingers should rest. A working prototype was created based on this foam model’s dimensions.

Prototype Construction

Casing was 3D printed from ABS.

Creating a dimple texture on the grip.

Internals inserted after finishing.

Power button on the bottom is always within a fingers reach

Lighter weight cord hangs down below the wrist

Rubber grips indicate where the fingers are meant to rest

The bent handle design caters to the more ergonomic overhand grip