wing-tube-joint.scad

   1 eps = 0.01;
   2 infty = 200;
   3
   4 wall = 1.5;
   5 thin_wall = 0.6;
   6
   7 tube_d = 8.0 + 0.2;
   8 base_w = 65;
   9 base_l = 30;
  10
  11 tube_d = 6 + 0.1;
  12 tube_zoff = 3;
  13
  14 base_w = 65;
  15 base_l = 30;
  16
  17 tube_l = base_l;
  18 base_overhang = 0.9; // factor of base_w, base_l
  19
  20 tube_zoff = 2;
  21
  22 module polyhole(r1, h1, fn) {
  23     rotate([0,0,180])
  24         cylinder(h = h1, r = r1 / cos (180 / fn), $fn = fn);
  25 }
  26
  27 module body(tube_zoff) {
  28         // base
  29         // scale([1, base_l/base_w, 1])
  30         // cylinder(r = base_w/2, h = thin_wall);
  31         translate([-base_w/2, -base_l/2, 0]) cube([base_w, base_l, thin_wall]);
  32
  33         // diagonal supports
  34         for (x = [-1,1])
  35         for (y = [-1,1])
  36         scale([x, y, 1])  hull() {
  37                 translate([base_overhang*base_w/2-thin_wall/2, base_overhang*base_l/2-thin_wall/2, 0])
  38                         cylinder(r = thin_wall/2, h = thin_wall, $fn = 16);
  39                 translate([0, -tube_l/3+thin_wall/2, 0])
  40                         cylinder(r = thin_wall/2, h = tube_zoff + tube_d, $fn = 16);
  41         }
  42
  43         // side supports
  44         for (x = [-1,1])
  45         for (y = [-1,1])
  46         scale([x, y, 1])  hull() {
  47                 translate([base_overhang*base_w/2-thin_wall/2, base_overhang*base_l/2-thin_wall/2, 0])
  48                         cylinder(r = thin_wall/2, h = thin_wall, $fn = 16);
  49                 translate([0, tube_l/2-thin_wall/2, 0])
  50                         cylinder(r = thin_wall/2, h = tube_zoff + tube_d, $fn = 16);
  51         }
  52
  53         // under the tube supports
  54         for (y = [-1,1])
  55         scale([1, y, 1])  hull() {
  56                 translate([0, base_overhang*base_l/2, 0])
  57                         cylinder(r = thin_wall/2, h = thin_wall, $fn = 16);
  58                 translate([-thin_wall/2, 0, 0])
  59                         cube([thin_wall, tube_l/2, tube_zoff]);
  60         }
  61
  62         // side bottom tube supports
  63         for (x = [-1,1])
  64         scale([x, 1, 1]) {
  65                 translate([tube_d/2, -tube_l/2, 0])
  66                         cube([wall, tube_l, tube_zoff + tube_d/2]);
  67                 translate([tube_d/2+wall, -wall, 0])
  68                         cube([wall, 2*wall, tube_zoff + tube_d/2]);
  69         }
  70
  71         // upper cylinder clip
  72         translate([0, -tube_l/2, tube_d/2 + tube_zoff])
  73         intersection() {
  74                 rotate([-90, 0, 0]) union() {
  75                         cylinder(r = tube_d/2 + wall, h = tube_l, $fn = 16);
  76                         translate([0, 0, tube_l/2 - wall])
  77                                 cylinder(r = tube_d/2 + 2*wall,
  78                                         h = 2*wall);
  79                 }
  80                 translate([-tube_d/2-2*wall, 0, 0])
  81                         cube([tube_d + 4*wall, tube_l, tube_d]);
  82         }
  83 }
  84
  85 module wing_tube_support(tube_zoff) {
  86         difference() {
  87                 body(tube_zoff);
  88                 // main tube
  89                 translate([0, -base_l/2-eps, tube_d/2+tube_zoff])
  90                 rotate([-90, 0, 0])
  91                         polyhole(tube_d/2, base_l + 2*eps, 6);
  92                         // cylinder(r = tube_d/2, h = base_l + 2*eps, $fn = 6);
  93                 // upper clip
  94                 translate([-infty/2, -infty/2, tube_zoff + tube_d + wall])
  95                         cube(infty);
  96         }
  97 }
  98
  99 wing_tube_support(tube_zoff);