poster-tube-lid: sloping bottom of catch tip

[reprap-play.git] / brompton-computer-guard.scad

diff --git a/brompton-computer-guard.scad b/brompton-computer-guard.scad
index 114c5e3f064113e453537869d1d7b11c85f0c3d1..35b0a182b6e9849e80609278345c2121e857b2ee 100644 (file)
--- a/brompton-computer-guard.scad
+++ b/brompton-computer-guard.scad
@@ -1,2 +1,106 @@
 // -*- C -*-
 
+arch_height = 18;
+arch_width = 75;
+end_width = 25;
+
+arch_thick = 4;
+
+arch_breadth = 25;
+
+hole_dia = 4 + 0.5;
+
+pbase_tab = 12;
+pbase_thick = 4;
+
+// computed
+
+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);
+
+inner_pbase_thick = 8;
+echo(inner_pbase_thick);
+
+inner_pbase_rad = arch_in_rad * 2;
+
+end_thick = arch_thick;
+
+holes = [[[  5  , 5  ], [16  , 21]], // left
+        [[ 18.5, 4.5], [ 4.5, 21]]]; // right
+
+module ArchCircle(rad){
+  translate([0,-arch_to_chord])
+    circle(rad, $fa=0.1);
+}
+
+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 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 MainCutout(){
+  ArchCircle(arch_in_rad);
+}
+
+module Arch(){
+  difference(){
+    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);
+           }
+         }
+       }
+      }
+    }
+    Holes();
+  }
+}
+
+rotate([0,0,45]) translate([0,0,arch_breadth]) rotate([0,180,0]) Arch();