wing-tube-joint.scad

   1 eps = 0.01;
   2 infty = 200;
   3
   4 wall = 1.5;
   5 thin_wall = 0.8;
   6
   7 tube_d = 8.0 + 0.2;
   8 base_w = 65;
   9 base_l = 30;
  10
  11 tube_zoff = 3;
  12
  13 base_w = 65;
  14 base_l = 30;
  15
  16 tube_l = base_l;
  17 base_overhang = 0.9; // factor of base_w, base_l
  18
  19 tube_zoff = 2;
  20
  21 module polyhole(r1, h1, fn) {
  22     rotate([0,0,180])
  23         cylinder(h = h1, r = r1 / cos (180 / fn), $fn = fn);
  24 }
  25
  26 module body(tube_zoff) {
  27         // base
  28         // scale([1, base_l/base_w, 1])
  29         // cylinder(r = base_w/2, h = thin_wall);
  30         translate([-base_w/2, -base_l/2, 0]) cube([base_w, base_l, thin_wall]);
  31
  32         // diagonal supports
  33         for (x = [-1,1])
  34         for (y = [-1,1])
  35         scale([x, y, 1])  hull() {
  36                 translate([base_overhang*base_w/2-thin_wall/2, base_overhang*base_l/2-thin_wall/2, 0])
  37                         cylinder(r = thin_wall/2, h = thin_wall, $fn = 16);
  38                 translate([0, -tube_l/3+thin_wall/2, 0])
  39                         cylinder(r = thin_wall/2, h = tube_zoff + tube_d, $fn = 16);
  40         }
  41
  42         // side supports
  43         for (x = [-1,1])
  44         for (y = [-1,1])
  45         scale([x, y, 1])  hull() {
  46                 translate([base_overhang*base_w/2-thin_wall/2, base_overhang*base_l/2-thin_wall/2, 0])
  47                         cylinder(r = thin_wall/2, h = thin_wall, $fn = 16);
  48                 translate([0, tube_l/2-thin_wall/2, 0])
  49                         cylinder(r = thin_wall/2, h = tube_zoff + tube_d, $fn = 16);
  50         }
  51
  52         // under the tube supports
  53         for (y = [-1,1])
  54         scale([1, y, 1])  hull() {
  55                 translate([0, base_overhang*base_l/2, 0])
  56                         cylinder(r = thin_wall/2, h = thin_wall, $fn = 16);
  57                 translate([-thin_wall/2, 0, 0])
  58                         cube([thin_wall, tube_l/2, tube_zoff]);
  59         }
  60
  61         // side bottom tube supports
  62         for (x = [-1,1])
  63         scale([x, 1, 1]) {
  64                 translate([tube_d/2, -tube_l/2, 0])
  65                         cube([wall, tube_l, tube_zoff + tube_d/2]);
  66                 translate([tube_d/2+wall, -wall, 0])
  67                         cube([wall, 2*wall, tube_zoff + tube_d/2]);
  68         }
  69
  70         // upper cylinder clip
  71         translate([0, -tube_l/2, tube_d/2 + tube_zoff])
  72         intersection() {
  73                 rotate([-90, 0, 0]) union() {
  74                         cylinder(r = tube_d/2 + wall, h = tube_l, $fn = 16);
  75                         translate([0, 0, tube_l/2 - wall])
  76                                 cylinder(r = tube_d/2 + 2*wall,
  77                                         h = 2*wall);
  78                 }
  79                 translate([-tube_d/2-2*wall, 0, 0])
  80                         cube([tube_d + 4*wall, tube_l, tube_d]);
  81         }
  82 }
  83
  84 module wing_tube_support(tube_zoff) {
  85         difference() {
  86                 body(tube_zoff);
  87                 // main tube
  88                 translate([0, -base_l/2-eps, tube_d/2+tube_zoff])
  89                 rotate([-90, 0, 0])
  90                         polyhole(tube_d/2, base_l + 2*eps, 6);
  91                         // cylinder(r = tube_d/2, h = base_l + 2*eps, $fn = 6);
  92                 // upper clip
  93                 translate([-infty/2, -infty/2, tube_zoff + tube_d + wall])
  94                         cube(infty);
  95         }
  96 }
  97
  98 wing_tube_support(tube_zoff);