Physical Demand Comparisons between Cleco’s Low Torque Reaction and Bosch’s ERGOSTOP Right-Angle Power-Tool Fastening Strategies

Abstract

The purpose of this work was to compare the physical demands associated with the right-angle power-tool (RAPT) operation when using Cleco’s Low Torque Reaction (LTR) and Bosch’s ERGOSTOP fastening strategies during simulated tightening of various joints. Twenty healthy participants (N=10 M, N=10 F, 21.1 ± 0.3 years) having no RAPT experience and no injuries to the arms or trunk participated in the study, however, 8 participants data were not analyzed due to equipment malfunction. Participants completed a five-minute bout of 5 joint fastening per minute for every experimental condition. Participant’s completed twelve total conditions including: 3 target torques (30, 55 and 75 Nm); 2 tightening strategies (Cleco’s Low Torque Reaction and Bosch’s ERGOSTOP); 2 joint hardness (Hard, which target torque was achieved at 30° of spindle rotation; Soft, which target torque was achieved at 520° of spindle rotation). All fastenings were completed with a common joint location-orientation of horizontal (53 cm), vertical (103 cm), lateral (35 cm) using a downward shot direction. Our data revealed that for all conditions (Target Torque, Joint Type & Tightening Strategy), Cleco’s LTR strategy resulted in lower physical demands. This is based on LTR fastenings resulting in lower push/pull magnitudes force impulse, peak forces and pulse-width times. From an ergonomics perspective, the reduction of physical force demand is a primary element of reducing the risk of work-related-musculoskeletal-disorders, the outcomes from this work was designed to aid ergonomists/engineers in understanding the physical demand magnitudes of RAPT operations in an effort to optimize manufacturing operations.