Powered screwdriver design and use: Tool, task, and operator effects

The study investigated three primary factors related to the ergonomic aspects of pneumatic screwdriver design and use. These factors were: (1) tool grip diameter, (2) tool weight, and (3) shut-off (reactive) torque. The study consisted of a simulated industrial assembly task, that was representative of many of today's industrial operations. The results of the study indicate that, for vertical hanging tools, the weight of the tool has very little effect on the operator and that higher shut-off torques require significantly more gripping force by the operator. Contrary to the popular industrial assumption, the larger grip diameters reduce the amount of gripping effort required at higher torques. However, at low torque levels, the grip diameter has much less effect. The implications for occupational safety, product quality and productivity are discussed. The results of the study are important to both manufacturers and users of powered screwdrivers.