topeak-mtx-tortec-expeditionrack-adapter: wip

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/topeak-mtx-tortec-expeditionrack-adapter.scad b/topeak-mtx-tortec-expeditionrack-adapter.scad
new file mode 100644 (file)
index 0000000..3996582
--- /dev/null
+++ b/topeak-mtx-tortec-expeditionrack-adapter.scad
@@ -0,0 +1,46 @@
+// -*- C -*-
+
+// brk_*: "bracket", the Topeak MTX bracket
+// rack_*: the Tortec rack
+// adapt_*: the adapter, ie this file
+
+brk_recess_actual = 5.20;
+
+rack_rail_dia = 10.40 + 0.50;
+rack_width_inner = 115.86 + 1.0; // between insides of rails
+
+rear_elevation_nominal = 10.04; // top of rack to bottom of bracket
+rear_to_front_distance = 230;
+
+general_gap_y = 1.0;
+
+main_sz_y = 20;
+grasp_sz = 12;
+
+// calculated
+
+brk_bottom_y = -brk_recess_actual;
+adapt_main_top_y = brk_bottom_y + general_gap_y;
+
+// on LHS, so -ve
+rack_rail_x = -(rack_width_inner + rack_rail_dia/2);
+rack_rail_outer_x = -(rack_width_inner + rack_rail_dia);
+
+grasp_large_r = (rack_rail_dia + grasp_sz)/2;
+grasp_large_x = rack_rail_outer_x + grasp_large_r;
+
+module Principal(){
+  // calculated
+  $rack_rail_y = brk_bottom_y - $elevation_nominal
+    - general_gap_y  - rack_rail_dia/2;
+
+  hull(){
+    translate([ grasp_large_x, adapt_main_top_y - grasp_large_r ])
+      circle(grasp_large_r);
+      
+    translate([ grasp_large_x, $rack_rail_y - rack_rail_dia/2 ])
+      circle(grasp_large_r);
+  }
+}
+
+Principal($elevation_nominal=0);