// -*- C -*-
-cable_maxdia = 12;
-cable_mindia = 6;
-strap_width = 4 + 0.5;
-total_len = 70;
+include <commitid.scad>
-wallmin = 1.5;
+rnom = 7.5 / 2;
-strap_count = 2;
+// alpha is slope angle, which is half of inner concave angle that
+// wire sits in
+alpha = 40; // degrees
-strap_wall_h = 1.5;
-strap_wall_l = 2.0;
+// mu is minimum number of cable radii that cable tangent point (line)
+// with splint ought to be away from edge of split
+mu = 1/4;
-delta_ellipse = 0.45;
+// wall thickness, and base width as fraction of cable size
+wall_r = 2.5 / 6.5;
+base_r = 0.75;
-// calculated
+// for cross-section calculations:
+//
+// origin O is at intersection of straight line segments forming walls
+// C is centre of circle (wire x-section) (of radius r or radius 1)
+// which is tangent to lines
+// T is said tangent points
+// B is inner base point, which is extension of line from B by mu*r
-delta_shift = 1 - delta_ellipse;
+sina = sin(alpha);
+cosa = cos(alpha);
+tana = sina/cosa;
-roundoff_rad = cable_maxdia/2 * sqrt(delta_shift)
- + cable_mindia/2 * (1-sqrt(delta_shift));
+// blah_r is blah where r=1
+// d_AB is distance AB
+// dy_AB is " " " vertical component
-outerdia = 2*(roundoff_rad / cos(30) + wallmin);
+d_OT_r = tana;
+d_OB_r = tana + mu;
-delta_shift_gap = (cable_maxdia-cable_mindia) * delta_shift;
+d_OC_r = 1/cosa;
-module CrossSection(plus=0) {
+dy_OB_r = d_OB_r * sina;
+
+// *0 and *1 relate to smallest and largest wire
+// r[01] is radius
+// r10 is radius ratio
+
+r10 = d_OC_r / dy_OB_r;
+
+r0 = rnom / sqrt(r10);
+r1 = rnom * sqrt(r10);
+
+x_B_r = d_OB_r * cosa;
+y_B_r = -dy_OB_r;
+
+x_T_r = sina;
+y_T_r = -tana * sina;
+
+wall_x_r = wall_r / tan(90-alpha);
+
+top = wall_r * r1 - (d_OC_r - 1) * r0;
+basew = base_r * rnom;
+
+echo("dias", r0*2, r1*2, "ratio",r1/r0);
+
+module CrossSectionHalf(plus=0) {
difference(){
- for (dx = [-plus, 0, plus])
- translate([dx, 0])
- circle(r= outerdia/2, $fn=6);
-
- intersection(){
- scale([cable_maxdia,
- cable_maxdia * delta_shift + cable_mindia * delta_ellipse])
- circle(r= sqrt(0.5) * delta_shift + 0.5 * delta_ellipse, $fn=4);
- circle(r= roundoff_rad, $fn=20);
- }
+ polygon([[-0.1, y_T_r * r0],
+ [x_T_r * r0, y_T_r * r0],
+ [x_B_r * r1, y_B_r * r1],
+ [x_B_r * r1 + wall_x_r * rnom + plus, y_B_r * r1],
+ [basew + plus, top],
+ [-0.1, top]]);
+ translate([0, -d_OC_r * r0])
+ circle(r = r0);
+ }
+}
- square(center=true, [40, delta_shift_gap]);
+module CrossSection(plus=0) {
+ for (m=[0,1]) {
+ mirror([m,0])
+ CrossSectionHalf(plus);
}
}
module CrossSectionDemo(){ ////toplevel
- color("blue"){
- translate([0, delta_shift_gap/2, 0]){
- difference(){
- circle(r = cable_maxdia/2, $fn=20);
- circle(r = cable_mindia/2, $fn=20);
- }
- }
+ color("black") CrossSection(2);
+ CrossSection();
+ for (rc=[["red", r1],
+ ["blue",r0]]) {
+ color(rc[0]) translate([0, -d_OC_r * rc[1]]) circle(r = rc[1]);
}
-
- linear_extrude(height=20)
- CrossSection(0);
-
- color("red")
- linear_extrude(height=1)
- CrossSection(2);
}
-module CompleteClamp(){ ////toplevel
- linear_extrude(height=total_len)
- CrossSection();
-
- for (i=[0 : strap_count]){
- if (i*2 != strap_count) {
- translate([0, 0,
- total_len * (i + 0.5) / (strap_count + 1)])
- for (m=[0,1]){
- mirror([0,0,m])
- translate([0,0, strap_width/2])
- linear_extrude(height=strap_wall_l)
- CrossSection(strap_wall_h);
+strap_width = 4 + 0.5;
+total_len = 70;
+
+strap_count = 2;
+
+strap_wall_h = 1.5;
+strap_wall_l = 2.0;
+
+writing_dx = total_len / 3;
+writing_dy = basew*2;
+
+module HalfClamp(){ ////toplevel
+ difference(){
+ rotate([90,0,0])rotate([0,90,0]){
+ linear_extrude(height=total_len)
+ CrossSection();
+
+ for (i=[0 : strap_count]){
+ if (i*2 != strap_count) {
+ translate([0, 0,
+ total_len * (i + 0.5) / (strap_count + 1)])
+ for (m=[0,1]){
+ mirror([0,0,m])
+ translate([0,0, strap_width/2])
+ linear_extrude(height=strap_wall_l)
+ CrossSection(strap_wall_h);
+ }
}
+ }
}
+
+ translate([0, -basew, top])
+ Commitid_BestCount([writing_dx, writing_dy]);
}
}
+module HalfClampPrint(){ ////toplevel
+ rotate([180,0,0])
+ HalfClamp();
+}
+
+//CrossSection();
//CrossSectionDemo();
-CompleteClamp();
+//HalfClamp();
+HalfClampPrint();