Torsion Coil Spring

FIG. 1 is a front view of a torsion coil spring, showing my new design; FIG. 2 is a rear view thereof; FIG. 3 is a right side view thereof; FIG. 4 is a left side view thereof; FIG. 5 is a top view thereof; FIG. 6 is a bottom view thereof; and, FIG. 7 is a cross-sectional view of a clasp for a fashion accessory, with the torsion coil spring disposed therein. The broken lines in FIG. 7 depict environment and form no part of the claimed design.