powerbank-bike-clamp.scad

   1 // -*- C -*-
   2
   3 tube_dia = 22.4;
   4
   5 hinge_around = 2.5;
   6 hinge_pin = 1.5; // xxx
   7 main_th = 3;
   8 minor_wall_min = 1;
   9
  10 screw = 5.0 + 0.75;
  11 screw_nut_across = 10; // xxx
  12 knob_behind_across = 15; // xxx
  13
  14 clamp_width = 15;
  15
  16 clamp_gap = 2;
  17
  18 lower_th = 1;
  19
  20 overlap_l = 0.1;
  21
  22 // calculated
  23
  24 main_r = tube_dia/2 + main_th;
  25
  26 hinge_outer_r = hinge_around + hinge_pin/2
  27 hinge_y = tube_dia/2 + hinge_outer_r;
  28
  29 screw_max_y_lhs = -main_r -screw_nut_across/2;
  30 screw_max_y_rhs = -main_r -knob_behind_across/2;
  31
  32 screw_y = min(screw_max_y_lhs,
  33               screw_max_y_rhs);
  34
  35 bot_y = -screw_y -max( screw_nut_across, knob_behind_across/2 )
  36   -minor_wall_min;
  37
  38
  39 module TubePlan(){ circle(r = tube_dia/2); }
  40 module HingePlan(){ translate([0, hinge_y]) circle(r= hinge_pin/2); }
  41 module HingeBodyPlan(){ translate([0, hinge_y]) circle(r= hinge_outer_r); }
  42
  43 module TubeClampLeftPlan(){
  44   difference(){
  45     union(){
  46       polygon([[ 0,                         hinge_y + hinge_outer_r ],
  47                [ -main_outer_r + overlap_l, hinge_y + hinge_outer_r ],
  48                [ -main_outer_r + overlap_l, bot_y                   ],
  49                [ -clamp_gap/2,              bot_y                   ],
  50                [ -clamp_gap/2,              0,                      ],
  51                [ 0,                         0,                      ],
  52                ]);
  53       HingeBodyPlan();
  54     }
  55     TubePlan();
  56     HingePinPlan();
  57   }
  58 }
  59
  60 module TubeClampLeft() { ////toplevel
  61   linextr(-clamp_width/2, clamp_width/2)
  62     TubeClampLeftPlan();
  63 }
  64
  65 TubeClampLeft();