Dexterity
Overview | Understanding dex. | Dex. functions (5) | Env. context | Design guidance | Pop. stats. (2)
Dexterity functions
Introduction | Pushing | Pinch gripping | Power gripping | Two-handed tasks
Pinch gripping is the ability to develop opposable forces between the thumb and fingers of the hand. Pinch grips are often used to manipulate controls such as sliders and knobs, which only require minimal forces. Pinch grips should not generally be used to generate large forces. Instead, more hand muscles can be employed by a power grip, thereby increasing the strength that can be brought to bear.
Careful provision of shape and surface texture of controls should allow the user to operate the product with a loose grip formed with his or her preferred combination of thumb and fingers.
The maximum rotational force that can be generated by a pinch grip is dependent on the size and shape of the object to be turned. Circular objects such as door knobs are the hardest to grip and turn as the fingers tend to slip on the surface. The best shape for pinch grip turning allows the thumb and fingers to grasp either side of long strip.
Satisfying products can be operated with a loose grip, and both of these controls could be manipulated with alternative grips
Frustrating products require a tight pinch grip to operate, and the shape and texture on these controls are not well matched to the direction and magnitude of the forces that are required
Overview | Understanding dex. | Dex. functions (5) | Env. context | Design guidance | Pop. stats. (2)