powerbank-bike-clamp: wip

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/powerbank-bike-clamp.scad b/powerbank-bike-clamp.scad
new file mode 100644 (file)
index 0000000..5724784
--- /dev/null
+++ b/powerbank-bike-clamp.scad
@@ -0,0 +1,65 @@
+// -*- C -*-
+
+tube_dia = 22.4;
+
+hinge_around = 2.5;
+hinge_pin = 1.5; // xxx
+main_th = 3;
+minor_wall_min = 1;
+
+screw = 5.0 + 0.75;
+screw_nut_across = 10; // xxx
+knob_behind_across = 15; // xxx
+
+clamp_width = 15;
+
+clamp_gap = 2;
+
+lower_th = 1;
+
+overlap_l = 0.1;
+
+// calculated
+
+main_r = tube_dia/2 + main_th;
+
+hinge_outer_r = hinge_around + hinge_pin/2
+hinge_y = tube_dia/2 + hinge_outer_r;
+
+screw_max_y_lhs = -main_r -screw_nut_across/2;
+screw_max_y_rhs = -main_r -knob_behind_across/2;
+
+screw_y = min(screw_max_y_lhs,
+             screw_max_y_rhs);
+
+bot_y = -screw_y -max( screw_nut_across, knob_behind_across/2 )
+  -minor_wall_min;
+
+
+module TubePlan(){ circle(r = tube_dia/2); }
+module HingePlan(){ translate([0, hinge_y]) circle(r= hinge_pin/2); }
+module HingeBodyPlan(){ translate([0, hinge_y]) circle(r= hinge_outer_r); }
+
+module TubeClampLeftPlan(){
+  difference(){
+    union(){
+      polygon([[ 0,                         hinge_y + hinge_outer_r ],
+              [ -main_outer_r + overlap_l, hinge_y + hinge_outer_r ],
+              [ -main_outer_r + overlap_l, bot_y                   ],
+              [ -clamp_gap/2,              bot_y                   ],
+              [ -clamp_gap/2,              0,                      ],
+              [ 0,                         0,                      ],
+              ]);
+      HingeBodyPlan();
+    }
+    TubePlan();
+    HingePinPlan();
+  }
+}
+
+module TubeClampLeft() { ////toplevel
+  linextr(-clamp_width/2, clamp_width/2)
+    TubeClampLeftPlan();
+}
+
+TubeClampLeft();