# enforce limits to x-axis in parametric_plot

I am trying to animate a classical harmonic oscillator (mass hooked to a spring attached to a wall). I have tried many variations of the following code to try to make the limits on the x-axis static: ...

springs=[parametric_plot3d([x,yy(x,t),zz(x,t)],(x,0,D(t)), xmin=0,xmax=11,plot_points=400,thickness=2) for t in sxrange (0,2,.2)]

b=animate(springs)

b.show(iterations=10)

The result is what appears to be a fixed spring with the coordinates of the x-axis changing rapidly. How can I use something similar to xmin and xmax in parametric_plot3d?