pulley-elliptical.scad

   1 infty = 100;
   2 eps = 0.01;
   3
   4 wall = 0.6;             // minimum wall
   5 d_x = 25;               // inner diameter in the X axis
   6 y_scale = 0.5;          // scale y/x
   7 height = 2.5;           // height of the rim
   8
   9 module half(d_x, y_scale, height) {
  10         hull($fn = 128) {
  11                 scale([1, (d_x*y_scale+height)/(d_x+height), 1])
  12                         cylinder(r = d_x/2 + height/2, h = eps);
  13                 translate([0, 0, height/2])
  14                         scale([1, y_scale, 1])
  15                         cylinder(r = d_x/2, h = eps);
  16         }
  17 }
  18
  19 module pulley(d_x, y_scale, height, center_hole_d) {
  20         difference() {
  21                 union() {
  22                         half(d_x, y_scale, height);
  23                         translate([0, 0, height]) scale([1, 1, -1])
  24                                 half(d_x, y_scale, height);
  25                 }
  26                 translate([0, 0, -eps])
  27                         cylinder(r = center_hole_d/2, h = height + 2*eps);
  28         }
  29 }
  30
  31 pulley(d_x = 15, y_scale = 0.5, height=2.5, center_hole_d = 3);
  32
  33 translate([0, 20, 0])
  34 pulley(d_x = 30, y_scale = 0.5, height=2.5, center_hole_d = 5);
  35