flat spring

spring.scad

module spring(width, id, od, count) {
    for(i = [0 : count]) {
        translate([-width/2, i*(od+id)]) square([width, od-id]);
        if (i < count) {
            mirror([i%2, 0, 0]) 
            translate([-width/2, (i*(od+id))+(od)]) 
            difference() {
                circle(od);
                circle(id);
                translate([0, -od*1.5]) square(od*3);
            }
        }
    }
}

linear_extrude(height=10)
spring(width=40, id=5, od=10, count=9);

I guess I messed up the names. id and od are actually the radii of the turns.