Technical Brief

Energy, Torque, and Dynamics in Impact Wrench Tightening

[+] Author and Article Information
Paul Wallace

Impact Fastening LLC,
Furlong, PA 18925
e-mail: pwwall@verizon.net

Contributed by the Manufacturing Engineering Division of ASME for publication in the JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING. Manuscript received July 31, 2014; final manuscript received October 3, 2014; published online December 12, 2014. Assoc. Editor: Tony Schmitz.

J. Manuf. Sci. Eng 137(2), 024503 (Apr 01, 2015) (8 pages) Paper No: MANU-14-1415; doi: 10.1115/1.4028750 History: Received July 31, 2014; Revised October 03, 2014; Online December 12, 2014

Dynamic measurements were made on an impact wrench tightening several bolted joints. Using hammer energy and bolted joint characteristics, energy absorbed by the joint and other parts of the system was calculated. The impact process is found to be consistent with an energy model in which kinetic energy of the tool hammer is primarily absorbed by the bolted joint. Hammer energy was also absorbed by elastic deformation of the tool output shaft and by friction-type losses in the components being assembled. Bolt torque is closely correlated with hammer energy delivered by the tool as was hammer rebound angle.

Copyright © 2015 by ASME
Topics: Torque , Hammers
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Industrial Fasteners Institute, 1996, “Impact Wrenches are a Bolt Supplier's Worst Enemy,” IFI Technical Bulletin, http://www.indfast.org/shop/display_products.asp?cat=20
Tsipeniyuk, Ya. I., and Gelfand, M. L., 1973, “Impact Tightening Screwed Fastenings,” Russ. Eng. J., LIII(11), pp. 68–69.
Archer, D., 2008, “Torque Audits are a Good Way to Check Joints,” Assembly Magazine, p. 8. Available at http://www.assemblymag.com/articles/85734-fastening-threads-torque-audits-are-a-good-way-to-check-joints
Arimura, T., 2008, “Impact Fastening Tool,” U.S. Patent 7,428,934 B2.


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Fig. 2

Joint torque–angle characteristic

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Fig. 3

Tool with RS232 connectivity

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Fig. 5

Hammer angular displacement versus time

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Fig. 1

Model of impact tightening a bolt

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Fig. 6

Torque versus number of impacts

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Fig. 7

Forward angle per impact versus torque

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Fig. 8

Hammer rebound angle versus torque



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