Special Section Technical Briefs

Evaluation of Extension Mechanism in an Implantable Limb Lengthening Device1

[+] Author and Article Information
Daniel Farley, Michael Zinn, Heidi-Lynn Ploeg

Department of Mechanical Engineering,
University of Wisconsin,
Madison, WI 53706

Accepted and presented at The Design of Medical Devices Conference (DMD2015), April 13–16, 2015, Minneapolis, MN, USA.

Manuscript received March 3, 2015; final manuscript received March 17, 2015; published online July 16, 2015. Editor: Arthur Erdman.

J. Med. Devices 9(3), 030903 (Sep 01, 2015) (2 pages) Paper No: MED-15-1058; doi: 10.1115/1.4030675 History: Received March 03, 2015; Revised March 17, 2015; Online July 16, 2015

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Grahic Jump Location
Fig. 1

Overview of extension mechanism prototype testing. (a) Extension mechanism prototype with sliding Teflon surfaces and crossed roller bearing assembly; (b) steel test frame loaded in series with extension mechanism, equipped with DC motor to drive the lead screw and force torque sensor to measure resistance torque; (c) complete system loaded in uniaxial testing machine; and (d) loading scenario modeled by prototype test fixture, showing prototype device mounted on adult femur.

Grahic Jump Location
Fig. 2

Representative data sets of reaction torque for sliding Teflon® (left) and crossed roller bearing (right) devices. Reaction torque is resistance torque used in torque margin equation.



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