Load-deflection rate measurements of activated open and closed coil springs.
The purpose of this investigation was to provide load-deflection rate data for a variety of open and closed coil springs. Ten millimeter lengths of open and closed coil stainless steel and Cobalt-Chromium-Nickel (Co-Cr-Ni) alloys in combinations of 0.008, 0.009 and 0.010 inch wire sizes, and 0.030 and 0.032 inch lumen sizes were tested. Other groups included heat treated Co-Cr-Ni springs and springs of 15 and 20 millimeter lengths. Forces and activations were measured by a tension load cell with an Instron universal testing instrument. Stiffness increased dramatically with wire size and pitch angle of the coils. Stiffness decreased slightly with increased lumen size. Co-Cr-Ni closed coil springs were slightly stiffer than stainless steel, whereas stainless steel open coil springs were much stiffer than Co-Cr-Ni. Heat treatment increased the stiffness of Co-Cr-Ni coil springs. The length of the spring had a great effect on the load-deflection rate. A shorter spring is stiffer than a longer spring by an amount directly proportional to the ratio of the length of the longer spring to that of the shorter spring.
Boshart
B F
BF
Department of Orthodontics, University of Oklahoma, Oklahoma City 73190.
Currier
G F
GF
Nanda
R S
RS
Duncanson
M G
MG
D002858:Chromium Alloys; D003799:Dental Stress Analysis; D004867:Equipment Design; D008422:Materials Testing; D009967:Orthodontic Appliances; D009969:Orthodontic Wires; D013193:Stainless Steel; D013314:Stress, Mechanical; D013499:Surface Properties
D002858:Chromium Alloys; D013193:Stainless Steel