From The Ergoweb® Learning Center

Pliers and Cutters

Dan MacLeod, CPE, MA, MPH

Common issues

PliersIntro
Squeeze force

Some tasks require a heavy squeeze force to cut or to hold an item. If done frequently, it can add to the cumulative strain on the hand and wrist. Furthermore, squeezing hard on a metal handle can cause a painful pressure point, which in some circumstances can injure the senstive tissue and blood vesels in the palm.

Another issue is the type of pliers or cutters. Hundreds of different styles are commercially available, making it possible to find tools that are better for certain tasks than the generic ones.

Common options for improvement

Reduce exertion

CuttersCompound
Compound levers: Maximize strength or minimize hand movement

Compound levers multiply squeeze force and minimize hand movement. The arrangement of the pivot points can be designed to maximize grip strength or minimize hand movement, or some combination in between.

RoboGrip
Grip diameter

The RoboGrip mechanism is designed to optimize the diameter of the hand grip maximum strength.

Mounted2 MountSmall
Custom benchtop cutting tool Quick setup using small vise

Mounting the tool cuts grip force by eliminating the need to generate opposing forces.  The photo above left shows a custom device created for a on-going need. The photo above right a quick setup for a small cutter for thin wires.  In this case, the force requirements were minimal, but the setup creates a simple machine that speeds the job while reducing physical demands.

Compound lever reversed crop Benchmount cutter
Bench mounted crimper Home made cutter

The examples above show different approaches to mounting tools and increasing leverage.

Grip cushioning

Cushion1

 

Multiple types

Parallel action pliers PliersCanvas
Parallel action Canvas grabber

 

Knipex plastic pliers Pliers plastic jaw 2
plastic plastic jaws

non-conductive protects items held from damage

 

 

x x

 

 

 

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plastic plastic jaws