Three Things to Know about “Ergonomic” Handles
Posted on July 12, 2022 | in Ergonomics
VelocityEHS’ Kent Hatcher explains what to look for in terms of handle design when purchasing or selecting power or manual hand tools. His video will help you ‘get a grip’ on what’s truly “ergonomic”.
Hi, I’m Kent Hatcher, a certified ergonomist here at Humantech (now VelocityEHS Ergonomics). In this month’s issue of our Ergo-Accelerator, I wrote a piece on ergonomic handles. The reason I wanted to do this was because there is still an overuse of the term “ergonomic” to describe handles out there in the marketplace. Unfortunately, there is no governing body that controls the use of the term “ergonomic,” so it gets applied in a lot of different situations.
So, what I wanted to do today was to show you some practical, real-life examples on how to apply proper hand tool selection guidelines. There are three main pillars of hand tool design selection criteria, and these hold true for both power tools and manual hand tools.
The first one would be handle length. Here’s an example of a box cutter, and you can see the length of the handle here. Although it’s sufficient for my hand, a hand that’s any bigger than mine is simply not going to fit, and there’s likely going to be a contact stress created on the edges of the hand, obstructing blood flow and increasing the chance of developing an injury. So, that’s the first pillar: handle length. The handle length should be about five and a half to six inches in order to accommodate the largest male’s hand.
The second pillar is handle diameter. The handle diameter of any tool should ideally be one and a half inches or right around there. That will accommodate the 5th percentile female’s hand to be able to get all the way around it in a full power grip. In addition, the handles should not have sharp edges like you see here because that also creates mechanical irritation, obstructing blood flow and increasing the chance of developing an injury.
The third pillar of hand tool selection has to do with tool versus target and the orientation of the handle relative to what you’re working on. If I hold this example here, this Exacto knife, you can see that when I’m going to be cutting on a horizontal surface, my wrist goes into an ulnar deviation. The same thing for these garden shears here. If I’m cutting on a flat surface, you can see the awkward posture that my right wrist goes into. Ideally, when we’re talking about tool versus target, there should be the ability to keep your hand in the handshake position. You can see in this particular tool – this is a nice gardening tool – the handle length is appropriate, the handle diameter is appropriate with no sharp edges, and it’s oriented to keep the wrist in as neutral a position as possible when working in the yard.
So, there you have it. Those are the three main pillars. That’s the “dirt” on hand tool selection guidelines. If you are able to get a grip on these selection guidelines, you will have no “trowel” at all selecting the right hand tool.
I’m Kent Hatcher. Thanks for watching.