powerbank-bike-clamp.scad

   1 // -*- C -*-
   2
   3 include <utils.scad>
   4
   5 tube_dia = 22.4;
   6
   7 hinge_around = 2.5;
   8 hinge_pin = 1.8 + 0.75;
   9 main_th = 3;
  10 minor_wall_min = 1;
  11
  12 screw = 5.0 + 0.75;
  13 screw_head = 8.7 + 1.2;
  14 screw_nut_across = 7.9 + 0.75;
  15 screw_nut_th = 3.9 + 0.75;
  16 screw_head_h = 3.6 + 0.75;
  17
  18 knob_behind_across = 12.2 + 0.75;
  19 behind_knob_th = 5;
  20
  21 clamp_width = 20;
  22
  23 clamp_gap = 2;
  24
  25 lower_th = 1;
  26
  27 overlap_l = 0.1;
  28
  29 bridge_slop_factor = 1.5;
  30
  31 hinge_lobes = 2;
  32 hinge_gap_z = 0.75;
  33 hinge_gap_xy = 0.75;
  34
  35 $fs = 0.1;
  36 $fa = 5;
  37
  38 // calculated
  39
  40 hinge_stride = (clamp_width + hinge_gap_z) / hinge_lobes;
  41
  42 main_r = tube_dia/2 + main_th;
  43
  44 hinge_outer_r = hinge_around + hinge_pin/2;
  45 hinge_y = tube_dia/2 + hinge_outer_r;
  46
  47 screw_max_y_lhs = -main_r -screw_nut_across/2;
  48 screw_max_y_rhs = -main_r -knob_behind_across/2;
  49
  50 screw_y = min(screw_max_y_lhs,
  51               screw_max_y_rhs);
  52
  53 bot_y = screw_y -max( screw_nut_across, knob_behind_across/2 )
  54   -minor_wall_min;
  55
  56 echo(bot_y);
  57
  58 module TubePlan(){ circle(r = tube_dia/2); }
  59 module HingePinPlan(){ translate([0, hinge_y]) circle(r= hinge_pin/2); }
  60 module HingeBodyPlan(){ translate([0, hinge_y]) circle(r= hinge_outer_r); }
  61
  62 module TubeClampLeftPlan(){
  63   difference(){
  64     union(){
  65       polygon([[ 0,                    hinge_y + hinge_outer_r ],
  66                [ -main_r + overlap_l,  hinge_y + hinge_outer_r ],
  67                [ -main_r + overlap_l,  bot_y                   ],
  68                [ -clamp_gap/2,         bot_y                   ],
  69                [ -clamp_gap/2,         0,                      ],
  70                [ 0,                    0,                      ],
  71                ]);
  72       HingeBodyPlan();
  73     }
  74     TubePlan();
  75     HingePinPlan();
  76   }
  77 }
  78
  79 module TubeClampLeft() { ////toplevel
  80   linextr(-clamp_width/2, clamp_width/2)
  81     TubeClampLeftPlan();
  82 }
  83
  84 module TubeClampRightPlan(){
  85   difference(){
  86     union(){
  87       rectfromto([ clamp_gap/2,                   bot_y ],
  88                  [ clamp_gap/2 + behind_knob_th,  0     ]);
  89       intersection(){
  90         circle(r= main_r);
  91         union(){
  92           rectfromto([0,0],
  93                       main_r *  [5,5]);
  94           rectfromto([ clamp_gap/2, main_r*5 ],
  95                       main_r * [2,-5]);
  96         }
  97       }
  98       HingeBodyPlan();
  99     }
 100     TubePlan();
 101     HingePinPlan();
 102   }
 103 }
 104
 105 module SomeClamp(hinge_alt=false){
 106   difference(){
 107     linextr(-clamp_width/2, clamp_width/2)
 108       children(0);
 109
 110     linextr_x_yz(-main_r*5, main_r*5)
 111       translate([screw_y, 0])
 112       circle(r= screw/2);
 113
 114     for (i=[0 : hinge_lobes-1]) {
 115       translate([0,
 116                  hinge_y,
 117                  -clamp_width/2 + i * hinge_stride
 118                  + (hinge_alt ? hinge_stride/2 : 0)
 119                  ])
 120         linextr(-hinge_gap_z, hinge_stride/2)
 121         square(hinge_outer_r*2 + hinge_gap_xy, center=true);
 122     }
 123   }
 124 }
 125
 126 module TubeClampLeft() { ////toplevel
 127   difference(){
 128     SomeClamp(true)
 129       TubeClampLeftPlan();
 130
 131     translate([0, screw_y, 0]) {
 132       linextr_x_yz(-(clamp_gap/2 + screw_nut_th), 0)
 133         square([screw_nut_across, screw_nut_across * bridge_slop_factor],
 134                center=true);
 135
 136       linextr_x_yz(-main_r, -main_r + screw_head_h)
 137         square([screw_head, screw_head * bridge_slop_factor],
 138                center=true);
 139     }
 140   }
 141 }
 142
 143 module TubeClampRight() { ////toplevel
 144   rotate([180,0,0])
 145     SomeClamp()
 146     TubeClampRightPlan();
 147 }
 148
 149 module TubeClampDemo() { ////toplevel
 150   TubeClampLeft();
 151   rotate([180,0,0])
 152     TubeClampRight();
 153 }