X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=reprap-play.git;a=blobdiff_plain;f=brompton-computer-guard.scad;h=35b0a182b6e9849e80609278345c2121e857b2ee;hp=6eade97538beb29099f821743169d05e118a97b5;hb=9f21563a34c99c15c3adcd2a72ab0da7cf741bbe;hpb=fb4b3e507088229a2d5436924c49b179360c2025

diff --git a/brompton-computer-guard.scad b/brompton-computer-guard.scad
index 6eade97..35b0a18 100644
--- a/brompton-computer-guard.scad
+++ b/brompton-computer-guard.scad
@@ -1,153 +1,106 @@
 // -*- C -*-
 
-cover_ysz = 45;
-cover_len = 70;
+arch_height = 18;
+arch_width = 75;
+end_width = 25;
 
-tube_dia = 18;
+arch_thick = 4;
 
-attach_cx = -15;
-attach_cdy = -5;
-attach_w = 25;
+arch_breadth = 25;
 
-attach_inrad = 25; ///
-attach_hole_dist = 5; ///
-attach_hole_dia = 4 + 0.5; ///
-attach_ang = 45;
+hole_dia = 4 + 0.5;
 
-attach_dz = 2;
+pbase_tab = 12;
+pbase_thick = 4;
 
-comp_dx = 22;
-comp_xsz = 45;
-comp_zsz = 28;
+// computed
 
-leftend_zsz = 10;
-leftend_dz = comp_zsz * 0.6;
+arch_alpha = atan(arch_height / (arch_width/2));
+arch_beta = 2*arch_alpha;
+echo(arch_alpha,arch_beta);
+arch_in_rad = arch_width/2 / sin(arch_beta);
+arch_to_chord = arch_in_rad * cos(arch_beta);
 
-min_thick = 4;
+inner_pbase_thick = 8;
+echo(inner_pbase_thick);
 
-rightend_thick = 10;
-bolthead_space = 4;
+inner_pbase_rad = arch_in_rad * 2;
 
-// calculated
+end_thick = arch_thick;
 
-cover_lcircle_r = cover_ysz / (1 + 1/sqrt(2));
+holes = [[[  5  , 5  ], [16  , 21]], // left
+	 [[ 18.5, 4.5], [ 4.5, 21]]]; // right
 
-base_len = cover_len - cover_lcircle_r;
-
-attach_end_r = attach_w/2;
-
-attach_straight_len =
-  attach_inrad + tube_dia + attach_hole_dist + attach_hole_dia/2
-  - attach_end_r + attach_hole_dist;
-
-attach_down = tube_dia/2 + attach_dz;
-
-attach_xmax = attach_cx +
-  cos(attach_ang) * attach_straight_len + attach_end_r;
-
-module RearSideTemplate(){
-  polygon([[0.1,0],
-	   [-base_len,0],
-	   [-base_len,-cover_ysz],
-	   [0.1,      -cover_ysz]]);
-  translate([-base_len, -cover_ysz + cover_lcircle_r])
-    circle(r=cover_lcircle_r);
+module ArchCircle(rad){
+  translate([0,-arch_to_chord])
+    circle(rad, $fa=0.1);
 }
 
-module AttachTemplate(){
-  hull(){
-    polygon([[0,   0],
-	     [-0.1, 0],
-	     [-0.1, -cover_ysz],
-	     [0,    -cover_ysz]]);
-    translate([attach_cx, -attach_cdy]) rotate([0,0,-attach_ang]) {
-      polygon([[-attach_cx,          attach_w/2],
-	       [0,                   -attach_w/2],
-	       [attach_straight_len, -attach_w/2],
-	       [attach_straight_len, attach_w/2]]);
-      translate([attach_straight_len, 0])
-	circle(r=attach_end_r);
+module ArchProfile(pbase){
+  intersection(){
+    translate([-200,0])
+      square([400,200]);
+    difference(){
+      union(){
+	ArchCircle(arch_in_rad + arch_thick);
+	for (m=[0,1])
+	  mirror([m,0])
+	    translate([arch_width/2,0])
+	    multmatrix([[1,pbase ? -0.75 : 0,0,0],
+			[0,1,0,0],
+			[0,0,1,0],
+			[0,0,0,1]])
+	    square([end_width, pbase ? pbase_tab : end_thick]);
+      }
     }
   }
 }
 
-module AttachElevation(anddown){
-  hull(){
-    translate([-cover_len - 0.5, leftend_dz - leftend_zsz/2])
-      square([1, leftend_zsz]);
-    translate([-comp_dx - comp_xsz/2, -0.1])
-      square([comp_xsz, comp_zsz + min_thick]);
-    translate([attach_xmax, 0])
-      square([1, rightend_thick + bolthead_space]);
-  }
-  if (anddown)
-    translate([-comp_dx, -attach_down-5])
-      square([comp_dx + attach_xmax+2, attach_down+6]);
-}
-
-module AttachElevationSelector(anddown) {
-  translate([0,100,0]) rotate([90,0,0]) linear_extrude(height=200)
-    AttachElevation(anddown);
-}
-
-module BodyPositive(){
-  intersection(){
-    linear_extrude(height=60) RearSideTemplate();
-    AttachElevationSelector(false);
-  }
-  intersection(){
-    translate([0,0,-attach_down]) linear_extrude(height=100) AttachTemplate();
-    AttachElevationSelector(true);
+module Holes(){
+  for (m=[0,1]) {
+    mirror([1-m,0])
+      translate([arch_width/2, 50, 0])
+      rotate([90,0,0])
+      for (h=holes[m]) {
+	translate(h)
+	  cylinder(r=hole_dia/2, h=100, $fn=20);
+      }
   }
 }
 
-module Cutouts(){
-  Tube();
-  Bolts();
+module MainCutout(){
+  ArchCircle(arch_in_rad);
 }
 
-module Body(){
+module Arch(){
   difference(){
-    intersection(){
-      BodyPositive();
-      translate([-100,-200,-100]) cube([200,200,200]);
+    rotate([0,0,180]){
+      linear_extrude(height=arch_breadth) {
+	difference(){
+	  ArchProfile(false);
+	  MainCutout();
+	}
+      }
+      difference(){
+	translate([0,0, arch_breadth - pbase_thick])
+	linear_extrude(height=pbase_thick){
+	  difference(){
+	    hull(){
+	      ArchProfile(true);
+	      ArchProfile(false);
+	    }
+	    intersection(){
+	      MainCutout();
+	      translate([0, -inner_pbase_thick
+			 - (inner_pbase_rad - arch_in_rad)])
+		ArchCircle(inner_pbase_rad);
+	    }
+	  }
+	}
+      }
     }
-    Cutouts();
+    Holes();
   }
 }
 
-module Tube(){
-  %translate([attach_cx, -attach_cdy, -tube_dia/2 - 0.1 - attach_dz]) {
-    rotate_extrude(convexity=10) {
-      translate([attach_inrad + tube_dia/2, 0])
-	circle(r=tube_dia/2);
-    }
-  }
-}
-
-module Bolt(){
-  translate([0,0,-50]) linear_extrude(height=80) {
-    circle(r=attach_hole_dia/2, $fn=20);
-  }
-  translate([0,0,rightend_thick]) linear_extrude(height=80) {
-    circle(r=attach_hole_dia/2 * 2, $fn=20);
-  }
-}
-
-module Bolts(){
-  translate([attach_cx, -attach_cdy]) rotate([0,0,-attach_ang]) {
-    translate([attach_inrad - attach_hole_dist - attach_hole_dia/2, 0])
-      Bolt();
-    translate([attach_inrad + tube_dia
-	       +attach_hole_dist + attach_hole_dia/2, 0])
-      Bolt();
-  }
-}
-
-module Demo(){
-  Cutouts();
-  %BodyPositive();
-}
-
-//Demo();
-Body();
+rotate([0,0,45]) translate([0,0,arch_breadth]) rotate([0,180,0]) Arch();