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 slot_w = 1.5;
  10 side_hole_d = 2.0;
  11
  12 thin_wall = 1;
  13 lever_l = 45;
  14 lever_h = 15.5;
  15 foam_h = 3;
  16
  17 module half(d_x, y_scale, height) {
  18         hull($fn = 128) {
  19                 scale([1, (d_x*y_scale+height)/(d_x+height), 1])
  20                         cylinder(r = d_x/2 + height/2, h = eps);
  21                 translate([0, 0, height/2])
  22                         scale([1, y_scale, 1])
  23                         cylinder(r = d_x/2, h = eps);
  24         }
  25 }
  26
  27 module pulley(d_x, y_scale, height, center_hole_d) {
  28         difference() {
  29                 union() {
  30                         half(d_x, y_scale, height);
  31                         translate([0, 0, height]) scale([1, 1, -1])
  32                                 half(d_x, y_scale, height);
  33                         // lever
  34                         hull() {
  35                                 translate([-lever_h, 0, 0])
  36                                         cube([lever_h, eps, thin_wall]);
  37                                 translate([-foam_h, -lever_l, 0])
  38                                         cube([foam_h, eps, thin_wall]);
  39                         }
  40                 }
  41                 translate([0, 0, -eps])
  42                         cylinder(r = center_hole_d/2, h = height + 2*eps);
  43                 translate([-slot_w/2, d_x*y_scale/2, -eps])
  44                         cube([slot_w, height, height + 2*eps]);
  45                 translate([0, center_hole_d/2 + (d_x*y_scale/2-center_hole_d/2)/2, -eps])
  46                         cylinder(r = side_hole_d/2, h = height + 2*eps);
  47         }
  48 }
  49
  50 pulley(d_x = 30, y_scale = 0.4, height=3, center_hole_d = 2.5);
  51
  52 // translate([0, 20, 0])
  53 // pulley(d_x = 35, y_scale = 0.4, height=2.5, center_hole_d = 8);
  54