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/2 + rack_rail_dia/2);
  30 rack_rail_outer_x = -(rack_width_inner/2 + 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 GraspElevation(){
  36   hull(){
  37     translate([ grasp_large_x, adapt_main_top_y - grasp_large_r ])
  38       circle(grasp_large_r);
  39
  40     translate([ grasp_large_x, $rack_rail_y - rack_rail_dia/2 ])
  41       circle(grasp_large_r);
  42
  43     translate([ grasp_large_x, $rack_rail_y + rack_rail_dia/2 ])
  44       circle(grasp_large_r);
  45   }
  46 }
  47
  48 module BlockElevation(){
  49   rectfromto([ -rack_width_inner/2, adapt_main_top_y ],
  50              [ +rack_width_inner/2, adapt_main_top_y - main_sz_y ]);
  51 }
  52
  53 module Principal(){
  54   // calculated
  55   $rack_rail_y = brk_bottom_y - $elevation_nominal
  56     - general_gap_y  - rack_rail_dia/2;
  57
  58   difference(){
  59     linextr(0, main_sz_z){
  60       GraspElevation();
  61       BlockElevation();
  62       mirror([1,0]) GraspElevation();
  63     }
  64
  65     linextr(-10, main_sz_z+10) {
  66       for (mx=[0,1]) {
  67         mirror([mx,0]) {
  68           translate([ rack_rail_x, $rack_rail_y ]){
  69             hull(){
  70               for (dx = [-rack_rail_dia, 0])
  71                 translate([dx, 0])
  72                   circle(r= rack_rail_dia/2);
  73             }
  74           }
  75         }
  76       }
  77     }
  78   }
  79 }
  80
  81 Principal($elevation_nominal=0);