There's no easy way to draw springs, coils, sinusoids, etc.  The only way to do this is with a bézier curve (too much precision required), hand-drawn (even more), or with ellipse arcs (and everyone knows how ugly a "sinusoid" drawn with half ellipses is).

It might be a good idea to include a line shape that allowed to draw
* a sinusoid
* a "coil" or "spring"
* a cycloid or trochoid (I doubt anyone actually wants to draw this, but it would be a particular case of "coil")

The parametric formula (for a horizontal coil) is

  { x = t * L/2pi + e*H/2 * cos(t+t0)
  { y = H/2 * sin(t+t0)
  { for t = 0 ... W / (L/2pi)

where H is the height (amplitude), W the width (length), L the distance between loops (wavelength), e the eccentricity (e=0: sinusoid; e=1: trocoid; 0<e<1: another coil-shaped line), and t0 the initial phase.