Muscle responses to torques of hand held power tools

Armstrong, Tina; Birl, Cindy; Finsen, Lotta; Foulkel, Jim; Martin, Bernard; Sjøgaard, Gisela; Tseng, K.-T.

doi:10.1016/0021-9290(94)91093-6

Cited by 4 publications

(5 citation statements)

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“…Radwin et al (1989) reported that torque impulse was significantly greater for longer build-up time, however, average hand force was significantly higher for shorter build-up time. Armstrong et al (1994) also reported that the average EMG from wrist flexors increased as build-up time decreased. They concluded that torque should build-up slowly (more than 250 ms) to minimize peak EMG.…”

Section: Discussionmentioning

confidence: 94%

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Dynamics of Power Hand Tools on Operator Hand and Arm Stability

Radwin

1994

Proceedings of the Human Factors and Ergonomics Society Annual

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Threaded fastener tightening was studied to determine effects of tool dynamics (torque and build-up time) and workstation configuration (orientation, horizontal distance and height) on operator kinematics and ability to stabilize a right-angle power hand tool. Hand velocity, hand displacement, tool torque, and spindle angle were recorded during tool operation. Four subjects participated. Workstation factors and tool dynamics had significant effects on hand stability. The magnitude of hand velocity and displacement was significantly greater for (1) vertical work surfaces compared to horizontal work surfaces; (2) vertical work surfaces higher than 90 cm above the ground; (3) horizontal work surfaces 90 cm above the ground; (4) increasing torque levels, and (5) long torque build-up times. Subjective ratings of perceived exertion were greater for increasing torque levels, long build-up times, and increasing workstation heights. Perceived exertion was significantly related to hand velocity and displacement (p<0.05), however, the strength of the correlation was small (R2 ranged between 0.01 and 0.10).

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Section: Discussionmentioning

confidence: 94%

“…Laboratory investigations have highlighted some factors that affect power tool operators during fastening (Armstrong et al, 1994;Freivalds et al, 1991;Kihlberg et al, 1993;Radwin et al, 1989;Ulin et al, 1992). These studies were somewhat limited.…”

Section: Introductionmentioning

confidence: 97%

Dynamics of Power Hand Tools on Operator Hand and Arm Stability

Radwin

1994

Proceedings of the Human Factors and Ergonomics Society Annual

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“…Although longer build-up tim e results in longer exertions and greater torque im pulse, it may have som e bene® ts in term s of tool control since it gives the operator a longer tim e to react. The eOE ect of torque build-up time on power hand tool operators has been studied in terms of perceived exertion, muscular activity and handle stability (Armstrong et al 1994, Freivalds and Eklund 1991, Lindqvist et al 1986, Oh and Radwin 1994, Radwin et al 1989. H owever, some of these previous ® ndings con¯ict.…”

Section: Discussionmentioning

confidence: 99%

“…These results led the authors to recommend that lower spindle speeds be used to minimize muscle response. Armstrong et al (1994) studied three torque build-up times (50, 250 and 450 ms) using a sim ulated tool handle, and reported that peak EM G from the ® nger¯exors increased as build-up time decreased. They also concluded that torque should build up slowly (longer than 250 ms) in order to minimize the peak EM G.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, previous ® ndings on torque build-up tim e are con¯icting. Radwin et al (1989) and Armstrong et al (1994) recommended the use of a longer build-up time (soft joint) based on muscular exertion measures, while Freivalds and Eklund (1991) and Lindqvist et al (1986) recomm ended a shorter build-up tim e in order to reduce torque impulse. For this reason, the current research attempts to broaden and solidify the basis on which this relationship is established by considering a greater range of torque and build-up times than previously used.…”

Section: Introductionmentioning

confidence: 99%

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The influence of target torque and torque build-up time on physical stress in right angle nutrunner operation

Radwin²

1998

Ergonomics

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This study used a computer-controlled electric right angle nutrunner to investigate the relative eOE ects of diOE erent power hand tool and process parameters on operator muscular exertions, handle stability and subjective ratings of perceived exertion. Target torque (25, 40 and 55 Nm), torque build-up time (35, 150, 300, 500 and 900 ms), and workstation orientation (horizontal and vertical) were studied. Dependent variables included EM G activity of the ® nger¯exors, biceps, and triceps, handle velocity and displacement, work done on the tool-hand system and power involved in doing work, subjective ratings of perceived exertion, and task acceptance. Six inexperienced subjects (three females and three males) participated. Ten replications were performed for each combination of experimental conditions. The consequences of increasing the torque reaction force were greater handle instability and perceived exertion. The eOE ect of torque buildup time on handle kinematics, muscular activity and perceived exertion was not monotonic. Among ® ve build-up times tested, the hand was most unstable (greater peak handle velocity and power against the operator) for a 150 ms buildup time. Greater peak handle displacement, total work against the operator and average EM G were observed for 150 and 300 ms build-up times than for other build-up time conditions. Integrated EM G and EM G latency signi® cantly increased as build-up time increased. Average EM G latency between the onset of EM G burst and the onset of torque build-up was 40 ms for a 35 ms build-up time and 330 ms for a 900 ms build-up time. Subjective ratings of perceived exertion were the least when torque build-up time was 35 ms, however greater peak torque variance was associated with this condition.

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The effects of power hand tool dynamics and workstation design on handle kinematics and muscle activity

Radwin

1997

International Journal of Industrial Ergonomics

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Muscle responses to torques of hand held power tools

Cited by 4 publications

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Dynamics of Power Hand Tools on Operator Hand and Arm Stability

Dynamics of Power Hand Tools on Operator Hand and Arm Stability

The influence of target torque and torque build-up time on physical stress in right angle nutrunner operation

The effects of power hand tool dynamics and workstation design on handle kinematics and muscle activity

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