Ergonomics - Hand Tool Design Ug 2008

Ergonomics DR. SITI ZAWIAH MD. DAWAL DEPT. OF ENGINEERING DESIGN AND MANUFACTURE UNIVERSITY OF MALAYA

Introduction  Human hand is able to

perform a large variety of activities ranging from those that require fine control to others that demand large forces.

Hand tasks can be divided:  Fine manipulation of objects with little

displacement and forces.  Fast movements toward the object, requiring moderately accuracy to reach the target but a fairly small exertion of force.  Forceful activities with little or moderate displacement  Forceful activities with large displacements

Designing Hand Tools

Fit the Tool  Hand tools need to fit the

contours of hand  Hand tools need to held securely with straight wrist and suitable arm postures  Hand tools must utilize strength and energy capabilities without overloading the body.

Many methods of gripping

Power Grip  Force parallel to forearm  Force at an angle of forearm  Force acting on a moment arm  Grip is used for force or holding heavy

product

Pinch Grip  Tools is held between the distal ends of  -

one or more fingers 4 types: Lateral pinch Pulp pinches Palm pinch Finger press

Avoid Tissue Compression

Handle Design

Oblique thrust line

Formfitting

Grip Strength Capability

Pulp Pinch Strength Capability

Proper orientation of power tools in workplace