topeak-mtx-tortec-expeditionrack-adapter.scad

   1 // -*- C -*-
   2
   3 // brk_*: "bracket", the Topeak MTX bracket
   4 // rack_*: the Tortec rack
   5 // adapt_*: the adapter, ie this file
   6
   7 include <utils.scad>
   8
   9 brk_recess_actual = 5.20;
  10
  11 rack_rail_dia = 10.40 + 0.50;
  12 rack_width_inner = 115.86 + 1.0; // between insides of rails
  13
  14 rear_elevation_nominal = 10.04; // top of rack to bottom of bracket
  15 rear_to_front_distance = 230;
  16
  17 general_gap_y = 1.0;
  18
  19 main_sz_z = 20; // xxx
  20 main_sz_y = 20;
  21 grasp_sz = 12;
  22
  23 // calculated
  24
  25 brk_bottom_y = -brk_recess_actual;
  26 adapt_main_top_y = brk_bottom_y + general_gap_y;
  27
  28 // on LHS, so -ve
  29 rack_rail_x = -(rack_width_inner + rack_rail_dia/2);
  30 rack_rail_outer_x = -(rack_width_inner + rack_rail_dia);
  31
  32 grasp_large_r = (rack_rail_dia + grasp_sz)/2;
  33 grasp_large_x = rack_rail_outer_x + grasp_large_r;
  34
  35 module Principal(){
  36   // calculated
  37   $rack_rail_y = brk_bottom_y - $elevation_nominal
  38     - general_gap_y  - rack_rail_dia/2;
  39
  40   difference(){
  41     linextr(0, main_sz_z){
  42       hull(){
  43         translate([ grasp_large_x, adapt_main_top_y - grasp_large_r ])
  44           circle(grasp_large_r);
  45
  46         translate([ grasp_large_x, $rack_rail_y - rack_rail_dia/2 ])
  47           circle(grasp_large_r);
  48
  49         translate([ grasp_large_x, $rack_rail_y + rack_rail_dia/2 ])
  50           circle(grasp_large_r);
  51       }
  52     }
  53
  54     linextr(-10, main_sz_z+10) {
  55       translate([ rack_rail_x, $rack_rail_y ]){
  56         hull(){
  57           for (dx = [-rack_rail_dia, 0])
  58             translate([dx, 0])
  59               circle(r= rack_rail_dia/2);
  60         }
  61       }
  62     }
  63   }
  64 }
  65
  66 Principal($elevation_nominal=0);