Investigation of triggering force by the index finger for optimal trigger design using a cadaver experiment

Joonho Chang, Andris Freivalds, Neil A. Sharkey, Yong Ku Kong, Hyun Min Kim, Kiseok Sung, Dae Min Kim

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

This study determined the optimal trigger grip span for the index finger and contact location between the index finger and trigger, using a cadaver experiment. Three fresh-frozen right male cadaveric hand specimens without any medical problem were employed, and the index finger motion simulator (IFMS), consisting of 1) support frame, 2) force measurement system, 3) motion delivery unit, and 4) operation system, was developed to support and control the specimens. The experiment consisted of two phases: triggering force was observed as a function of 1) grip spans (40, 50, 60 mm) and 2) three contact locations on the middle of the distal to the middle of the medial phalange. Also, three levels of total tendon forces (FDP + FDS: 40, 70, and 100 N) were applied to both phases. As a result, at Phase I, the maximum triggering forces, 8.9, 15.0, and 20.0 N, were obtained at 50 mm grip span for total tendon forces respectively. At Phase II, The contact location on the middle of the medial phalange showed the maximum triggering forces, 10.1, 18.2, and 28.2 N, for the total tendon forces respectively. Force efficiency, triggering force to tendon force ratio, showed approximately 10 to 30% of internal tendon force was converted into external trigger force. On the basis of the results of this study, 50 mm grip span and the contact location on the middle of the medial phalange were recommended for optimal trigger design.

Original languageEnglish
Title of host publication2014 International Annual Meeting of the Human Factors and Ergonomics Society, HFES 2014
PublisherHuman Factors an Ergonomics Society Inc.
Pages1546-1550
Number of pages5
ISBN (Electronic)9780945289456
DOIs
StatePublished - 2014
Event58th International Annual Meeting of the Human Factors and Ergonomics Society, HFES 2014 - Chicago, United States
Duration: 27 Oct 201431 Oct 2014

Publication series

NameProceedings of the Human Factors and Ergonomics Society
Volume2014-January
ISSN (Print)1071-1813

Conference

Conference58th International Annual Meeting of the Human Factors and Ergonomics Society, HFES 2014
Country/TerritoryUnited States
CityChicago
Period27/10/1431/10/14

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