3 // brk_*: "bracket", the Topeak MTX bracket
4 // rack_*: the Tortec rack
5 // adapt_*: the adapter, ie this file
9 // strength factor, set to 1 for real prints
13 brk_recess_actual = 5.20;
15 rack_rail_dia = 10.40 + 0.30;
16 rack_width_inner = 115.86 - 1.0; // between insides of rails
18 rear_elevation_nominal = 10.04;
19 // ^ top of rack to bottom of bracket, at rack cross rail (fam)
20 rear_to_front_distance = 230; // rack cross rail (fam) to very front end
21 rear_to_cross_rail = 43.05; // bolt centre to rail centre, rail to rear
22 rear_bolt_to_front_bolt = 155.4;
23 front_to_cross_rail = 43.05; // XXX // bolt centre to rail centre, rail to front
24 front_elevation_nominal = 3;
30 strap_barrel_dia = 14;
34 brk_block_z = 14.55 - 0.00;
36 brk_bolt_dia = 5.0 + 0.5;
37 brk_nearbolt_recess_dia = 8.86 + 1.5;
38 brk_nearbolt_recess_depth = 1.09 + 0.25;
40 brk_bolt_eff_len = 11.78; // inside of recess, to end of bolt
41 brk_bolt_len_slop = 0.5;
42 brk_bolt_nut_th = 3.89;
43 brk_bolt_nut_across_flats = 7.86 + 0.50;
45 brk_overall_w = 90.07;
49 // "foreaftmaint" aka "fam" is the hook-like part that stops
50 // the adapter sliding forwards/backwards along the rails
51 foreaftmaint_r_slop = 0.0;
52 foreaftmaint_y_slop = -0.25;
53 foreaftmaint_top_block_zs = [34.0, 39.0]; // rearwards from bolt hole
55 main_sz_y = $strf * 12;
57 grasp_thin_sz = $strf * 0.5;
58 beside_strap_sz = $strf * 8;
59 main_sz_core_z = $strf * 12;
61 // "length" in for-aft direction of interaction with rack rail
62 min_on_rail_sz_z = $strf * 18;
64 // when printer produces support
65 support_around = 1.7; // how far does the support extend around (in XY)
66 support_remnant = 0.75; // how much frass remains attached (Z height)
73 bolt_z = -brk_block_z/2;
75 main_sz_rhs_z = max(min_on_rail_sz_z, beside_strap_sz*2 + strap_w);
76 main_sz_lhs_z = min_on_rail_sz_z;
78 main_sz_x_fam = main_sz_y;
80 brk_bottom_y = -brk_recess_actual;
81 adapt_main_top_y = brk_bottom_y - general_gap_y;
84 rack_rail_x = -(rack_width_inner/2 + rack_rail_dia/2);
85 rack_rail_outer_x = -(rack_width_inner/2 + rack_rail_dia);
87 grasp_large_r = (rack_rail_dia + grasp_sz)/2;
88 grasp_small_r = (rack_rail_dia + grasp_thin_sz)/2;
89 grasp_large_x = rack_rail_outer_x + grasp_large_r;
90 grasp_small_x = rack_rail_outer_x + grasp_small_r;
92 block_x = grasp_large_x + grasp_large_r;
93 block_y_min = adapt_main_top_y - main_sz_y;
95 strap_barrel_x = rack_width_inner/2 + strap_barrel_dia/2;
97 rack_shear_ratio = -rear_elevation_nominal / rear_to_front_distance;
99 brk_bolt_nut_top_y = -brk_nearbolt_recess_depth
100 - brk_bolt_eff_len + brk_bolt_nut_th + brk_bolt_len_slop;
102 brk_bolt_nut_r = brk_bolt_nut_across_flats/2 / cos(360/12);
104 function elevation_of_bolt_for(z) = rear_elevation_nominal
105 + front_elevation_nominal
106 + (z - brk_block_z/2) * rack_shear_ratio;
108 function rack_rail_y_of_elevation(elevation_nominal) =
109 brk_bottom_y - elevation_nominal - general_gap_y - rack_rail_dia/2;
111 echo(rack_shear_ratio);
113 module GraspElevation(){
115 translate([ grasp_large_x, adapt_main_top_y - grasp_large_r ])
116 circle(grasp_large_r);
118 translate([ grasp_small_x, $rack_rail_y - rack_rail_dia/2 ])
119 circle(grasp_small_r);
121 translate([ rack_rail_x + grasp_large_r/2,
122 $rack_rail_y - rack_rail_dia/2 ])
123 circle(grasp_small_r);
125 translate([ grasp_large_x, $rack_rail_y + rack_rail_dia/2 ])
126 circle(grasp_large_r);
128 translate([ grasp_large_x + grasp_large_r/2,
129 $rack_rail_y + rack_rail_dia/2 ])
130 circle(grasp_large_r);
134 module BlockElevation(){
136 rectfromto([ +block_x, adapt_main_top_y ],
137 [ -block_x, block_y_min ]);
138 rectfromto([ -grasp_large_x, adapt_main_top_y ],
139 [ +grasp_large_x, adapt_main_top_y - 0.1 ]);
142 rectfromto([ +block_x, adapt_main_top_y ],
143 [ -block_x, block_y_min ]);
144 rectfromto([ grasp_large_x, block_y_min ],
145 [ 0, block_y_min + 0.1 ]);
149 module MainExtrude(z){
154 s = rack_shear_ratio * $reverse_sign;
155 multmatrix([ [ 1, 0, 0, 0 ],
162 module GraspFixingElevation(){
169 translate([ -block_x, block_y_min ] + [0,0.1]*1 )
172 translate([ strap_barrel_x, $strap_barrel_y ])
173 circle(strap_barrel_dia/2 + strap_guide_sz);
176 rectfromto([0, $rack_rail_y],
177 [rack_width_inner, 50]);
179 translate([ rack_rail_x, $rack_rail_y ])
180 circle(r = rack_width_inner/2 - rack_rail_x);
181 polygon([ [ -block_x-0.1, 0 ],
182 [ rack_width_inner/2, 0 ],
183 $rail_fixing_fit_corner,
184 $rail_fixing_fit_corner + [-1,-1] * fit_slope_len,
185 [ -grasp_large_x - grasp_large_r*2, block_y_min ],
186 [ -block_x-0.1 -2, block_y_min +2 ]]);
192 module StrapBarrelElevation(){
193 translate([ strap_barrel_x, $strap_barrel_y ])
194 circle(strap_barrel_dia/2);
197 // Bracket support block, goes up inside bracket
198 // Z origin is bolt hole
201 linextr( -brk_block_z/2,
203 rectfromto([ -brk_block_xw/2, adapt_main_top_y - 0.1 ],
204 [ +brk_block_xw/2, 0 ]);
206 linextr_y_xz( -50, 10 ) {
207 translate([ 0, brk_block_z + bolt_z ])
209 [ main_sz_x_fam + support_around*2,
210 support_remnant *2 ]);
215 // Z origin is bolt hole
217 linextr_y_xz( -100, 10 )
218 circle(brk_bolt_dia/2);
220 linextr_y_xz( -brk_nearbolt_recess_depth, 10)
221 circle(brk_nearbolt_recess_dia/2);
223 linextr_y_xz( -100, brk_bolt_nut_top_y ) {
224 circle( r= brk_bolt_nut_r, $fn = 6 );
225 translate([ 0, brk_bolt_nut_across_flats/2 ])
226 circle( r=brk_bolt_nut_r/2, $fn = 4);
231 if ($foreaftmaint_dz) {
238 linextr_x_yz(-main_sz_x_fam/2, +main_sz_x_fam/2)
243 module FamGraspElevation(){
245 ybot = $rack_rail_y - rack_rail_dia/2 + grasp_large_r
246 - fit_slope_len * 0.5;
249 adapt_main_top_y - grasp_large_r
251 for (dx= [/*-1,*/ +1] * rack_rail_dia/2)
252 translate([ -$foreaftmaint_rail_z + dx, y ])
253 circle(r= grasp_large_r);
259 $rack_rail_y = rack_rail_y_of_elevation($elevation_nominal);
261 $strap_barrel_y = $rack_rail_y + rack_rail_dia/2 + strap_barrel_dia/2;
263 $rail_fixing_fit_corner = [
265 $rack_rail_y - rack_rail_dia/2
268 $foreaftmaint_rail_z = brk_block_z/2 + $foreaftmaint_dz - foreaftmaint_y_slop;
270 translate([0,0,brk_block_z/2])
271 mirror([0,0, $reverse_sign > 0 ? 0 : 1])
272 translate([0,0,-brk_block_z/2])
275 MainExtrude(main_sz_lhs_z){
278 RackShear() MainExtrude(main_sz_rhs_z){
279 StrapBarrelElevation();
281 translate([ 0,0, brk_block_z/2]) {
287 MainExtrude(main_sz_core_z){
291 MainExtrude(max(brk_block_z, main_sz_rhs_z)){
292 rectfromto([-8, adapt_main_top_y + 0.1],
294 rectfromto([-block_x -5, adapt_main_top_y],
295 [-grasp_large_x, block_y_min]);
298 RackShear() MainExtrude(main_sz_rhs_z){
299 GraspFixingElevation();
303 translate([0,0, main_sz_rhs_z/2]) linextr(-strap_w/2, +strap_w/2) {
304 translate([ rack_width_inner/2 - strap_th, 0 ])
305 rectfromto([ 0, -50 ], [ 50, 50 ]);
310 rectfromto([ -$foreaftmaint_rail_z, adapt_main_top_y ],
312 rectfromto([ -foreaftmaint_top_block_zs[0] + bolt_z, 0 ],
313 [ -foreaftmaint_top_block_zs[1] + bolt_z, block_y_min] );
321 adapt_main_top_y - 50,
322 $foreaftmaint_rail_z ])
323 cube(center=true, 100);
327 RackShear() linextr(-10, main_sz_lhs_z+main_sz_rhs_z) {
330 translate([ rack_rail_x, $rack_rail_y ]){
332 for (dx = [-rack_rail_dia, 0])
334 circle(r= rack_rail_dia/2);
342 // Distance from bolt hole, in backwards direction
343 cr = rack_rail_dia/2 + foreaftmaint_r_slop;
344 translate([ 0, $rack_rail_y, $foreaftmaint_rail_z ])
345 linextr_x_yz(+rack_rail_x,
354 for (dd=[[0,0], [-1,-1], [-1,+1]]) {
356 [-1, 0] * (rack_rail_dia - fit_slope_len)
365 translate([ 0,0, brk_block_z/2]) BoltHole();
369 module RackForDemo(){ ////toplevel
370 elevation = elevation_of_bolt_for(rear_to_cross_rail);
371 rack_rail_y = rack_rail_y_of_elevation(elevation);
373 rotate([-atan(rack_shear_ratio), 0,0])
374 translate([0, rack_rail_y, brk_block_z/2 + rack_rail_y*rack_shear_ratio]) {
375 for (m=[0]) mirror([m,0,0]) {
376 linextr(-50, 50 + rear_to_cross_rail)
377 translate([rack_rail_x, 0])
378 circle(r= rack_rail_dia/2);
380 translate([0,0, rear_to_cross_rail])
381 linextr_x_yz(rack_rail_x, -rack_rail_x)
382 circle(r= rack_rail_dia/2);
386 module Front(){ ////toplevel
387 // xxx elevation is wrong
388 Principal($reverse_sign = -1,
390 elevation_of_bolt_for(rear_to_cross_rail + rear_bolt_to_front_bolt),
391 $foreaftmaint_dz= front_to_cross_rail);
394 module Rear(){ ////toplevel
395 Principal($reverse_sign = +1,
397 elevation_of_bolt_for(rear_to_cross_rail),
398 $foreaftmaint_dz= rear_to_cross_rail);
406 translate([ 0, -2, -4 ])
407 square(center=true, [ brk_overall_w, 1 ]);
410 translate([ 0, -brk_nearbolt_recess_depth, -4 ])
411 linextr_y_xz(-brk_bolt_eff_len, 0)
412 circle(r = brk_bolt_dia/2);
417 module FrontDemo(){ ////toplevel
420 module RearDemo(){ ////toplevel
423 module RearRackDemo(){ ////toplevel
424 rotate([atan(rack_shear_ratio),0,0]) SomeDemo() {