The contact length parameter as a geometric factor for user-centered design of pistol grip geometries of power tools

René Germann; Nils Schröder; Sven Matthiesen

doi:10.1016/j.apergo.2021.103636

The contact length parameter as a geometric factor for user-centered design of pistol grip geometries of power tools

Appl Ergon. 2022 Feb:99:103636. doi: 10.1016/j.apergo.2021.103636. Epub 2021 Nov 10.

Authors

René Germann¹, Nils Schröder¹, Sven Matthiesen²

Affiliations

¹ IPEK - Institute for product engineering at Karlsruhe Institute of Technology (KIT), Kaiserstr. 10, 76131, Karlsruhe, Germany.
² IPEK - Institute for product engineering at Karlsruhe Institute of Technology (KIT), Kaiserstr. 10, 76131, Karlsruhe, Germany. Electronic address: sven.matthiesen@kit.edu.

PMID: 34773741
DOI: 10.1016/j.apergo.2021.103636

Abstract

In this study the geometric parameter of the contact length is introduced, which intends to combine force exertion and perceived handle comfort in an anthropometric length in order to determine an optimal handle circumference. To prove suitability of the approach, 31 subjects were determined and correlations to handle circumferences with the highest finger forces and highest rated comfort were investigated. For all fingers, medium correlations were found among the contact lengths and the circumferences determined with maximum force (p < 0.001, r_index = 0.348, r_middle = 0.419, r_ring = 0.374 and r_little = 0.337) with high accordance of median values. Weak to moderate correlations were found between circumferences with maximum comfort and the contact lengths (p < 0.001, r_index = 0.150, r_middle = 0.265, r_ring = 0.174). Using finger-specific proportionality factors, the contact lengths can be determined directly from the hand lengths, which enables great benefits for user-centered design.

Keywords: Cordless screwdriver; Finger force; Handle design; Perceived usability; Power tools.

MeSH terms

Equipment Design
Fingers
Hand
Hand Strength*
Humans
User-Centered Design*