A field investigation of manual forces associated with trigger and push to start electric screwdrivers.
Lowe-BD; Kong-Y-K; Krieg-E; Wurzelbacher-S; Lee-S-J
Hum Factors Ergon Manuf 2007 May; 17(4):367-382
This study investigated manual forces associated with trigger start (TS) and push to start (PTS) activation in-line electric screwdriver designs. The vertically directed axial screwdriver force transmitted with the driver to the fastener and the grip/finger forces on the driver handle were measured from 13 employees in an electronics assembly manufacturing facility. The PTS driver was associated with significantly ( p < .01) higher axial force than the TS driver at two of the four workstations, where the difference was as high as a 184% increase (36.5 vs. 103.8 N). Total finger force on the screwdriver handle was also higher for the PTS screwdriver ( p < .01). The PTS screwdriver may reduce instances of fastener head damage (cam out) by requiring a minimum level of axial force to ensure better contact between the screwdriver bit and the fastener. However, this appears to come at the expense of greater manual forces exerted by the operator.
Physical-reactions; Physical-properties; Electrical-equipment; Electronic-devices; Tools; Equipment-operators; Equipment-reliability; Force; Machine-tools
Brian D. Lowe, National Institute for Occupational Safety and Health, Robert A. Taft Laboratories, 4676 Columbia Parkway, Mail Stop C-24, Cincinnati, OH 45226
Human Factors and Ergonomics in Manufacturing