X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=reprap-play.git;a=blobdiff_plain;f=cliphook.scad;h=22f08f54ec09a1d7d441488b755ded87f6cb753d;hp=de9c4ae18c87d4718e81b24cef44aeacf089ffd5;hb=cf422612d5746988fc11fbadcae42542f7f48a43;hpb=a0d95a03db72ade8e242e8a971fc2bc86a0b1e2b

diff --git a/cliphook.scad b/cliphook.scad
index de9c4ae..22f08f5 100644
--- a/cliphook.scad
+++ b/cliphook.scad
@@ -1,56 +1,103 @@
-
-tau = 6.283;
-function rads2degs(rads) = rads * 360/tau;
+// -*- C -*-
+//
+// cliphook.scad
+//
+// 3D design for a small clippy hook
+// Copyright 2012,2016 Ian Jackson
+//
+// This work is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This work is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this work.  If not, see <http://www.gnu.org/licenses/>.
 
 function ClipHook_r2(w,g,l,ye,k) = w/2 + g + w/2;
-function ClipHook_r3(w,g,l,ye,k) = k * ClipHook_r2(w,g,l,ye,k);
-function ClipHook_yce(w,g,l,ye,k) = g/2 + w + g + w/2 - ClipHook_r3(w,g,l,ye,k);
+function ClipHook_r3(w,g,l,ye,k) = k * (ClipHook_r2(w,g,l,ye,k) + w + g);
+function ClipHook_yd(w,g,l,ye,k) = g/2 + w + g + w/2 - ClipHook_r3(w,g,l,ye,k);
 function ClipHook_xe(w,g,l,ye,k) =
+        l*1.5 + w +
 	sqrt(pow( ClipHook_r3(w,g,l,ye,k),      2) -
-	     pow( ClipHook_yce(w,g,l,ye,k) + ye, 2));
+	     pow( ClipHook_yd(w,g,l,ye,k) - ye, 2));
 
-module ClipHook(w=1.2, g=0.2, l=0.0, ye=0, k=3.0, h=3.5) {
+module FlatArc(cx,cy,r1,r2,a1,a2=361,$fn=$fn) {
+  astep = (a2-a1)/6;
+  size = 5*(r2/2);
+  translate([cx,cy,0]) {
+    intersection() {
+      difference() {
+	circle(r=r2);
+	translate([0,0,-1])
+	  circle(r=r1);
+      }
+      scale(size) {
+	for (ai=[0:4]) {
+	  //echo(" jarc ", a1,a2, astep, ai, a1 + astep*ai );
+	  rotate(a1 + astep*ai) {
+	    polygon([ [0,0], [1,0],
+		      [cos(astep*2),sin(astep*2)] ]);
+	  }
+	}
+      }
+    }
+  }
+}
+
+module ClipHook_2D(w,g,l,ye,k,h) {
   r2 =  ClipHook_r2(w,g,l,ye,k);
   r3 =  ClipHook_r3(w,g,l,ye,k);
-  yce = ClipHook_yce(w,g,l,ye,k);
+  yd =  ClipHook_yd(w,g,l,ye,k);
   xe =  ClipHook_xe(w,g,l,ye,k);
 
+  xd = l*1.5 + w;
   xc = -l/2;
-  yc = g/w + w/2;
+  yc = g/2 + w/2;
+
+  alpha = atan2((xe-xd)/r3, (ye-yd)/r3);
 
   echo("ClipHook(w g l ye k h) ", w, g, l, ye, k, h);
-  echo("ClipHook r2 r3 yce xe =", r2, r3, yce, xe);
+  echo("ClipHook r2 r3 xd yd xe =", r2,r3, xd,yd, xe);
 
   $fn = 20;
 
   module jcirc(x,y) { translate([x,y,0]) circle(r=w/2); }
-  module jarc(cx,cy,r,a1=0,a2=tau) {
-    astep = (a2-a1)/6;
-    size = 5*(r+w/2);
-    translate([cx,cy,0]) {
-      intersection() {
-	difference() {
-		circle(r=r+w/2);
-		translate([0,0,-1])
-			circle(r=r-w/2, h=h+2);
-	}
-	scale(size,size) {
-	  for (ai=[0:4]) {
-	    echo(" jarc ", a1,a2, astep, ai, rads2degs(a1 + astep*ai) );
-	    rotate(rads2degs(a1 + astep*ai)) {
-	      polygon([ [0,0], [1,0],
-			[cos(rads2degs(astep*2)),sin(rads2degs(astep*2))] ]);
-	    }
-	  }
-	}
-      }
+  module jbox(y,x1,x2) { translate([x1,y-w/2,0]) square(size=[x2-x1, w]); }
+  module jarc(cx,cy,r,a1=0,a2=360) { FlatArc(cx,cy,r-w/2,r+w/2,a1,a2); }
+
+  jcirc(-xc, -yc);
+  jbox(-yc, xc, -xc);
+  jarc(xc, yc, r2, 90, 270);
+  jbox(yc+r2, xc, xd);
+  jarc(xd, yd, r3, 90-alpha, 90);
+  jcirc(xe,ye);
+}
+
+module ClipHook(w=1.2, g=0.2, l=0.0, ye=0, k=2.0, h=3.5, demo=false,
+		cupcaph=0, cupgapg=0) {
+  difference() {
+    linear_extrude(height=h)
+      ClipHook_2D(w,g,l,ye,k);
+    if (cupcapg != 0) {
+      translate([-g+0.01,-(w+g),h-cupcapg])
+      cube([w,(w+g),cupcaph+1]);
     }
   }
-
-  linear_extrude(height=h) {
-    jcirc(-xc, -yc);
-    jarc(xc, yc, r2, tau*0.25, tau*0.75);
+  if (cupcaph != 0) {
+    translate([-l/2, g/2+w/2, h-0.01])
+      intersection() {
+        cylinder(r=ClipHook_r2(w,g,l,ye,k)+w*0.4, h=cupcaph, $fn=16);
+	translate([-50-g,-50,-1]) cube([50,100,h+2]);
+      }
   }
 }
 
-ClipHook(l=3);
+if (ClipHook_demo) {
+  ClipHook(l=0, k=1, cupcaph=1, cupcapg=0.4);
+  %translate([l+w,0,0]) rotate(180) ClipHook(l=0, k=1, cupcaph=1, cupcapg=0.4);
+}