better shape of spring tensioner split

1 files changed, 8 insertions, 3 deletions

diff --git a/another.scad b/another.scad
index 92187c5..8ba0d58 100644
--- a/another.scad
+++ b/another.scad
@@ -39,96 +39,98 @@ module the_extruder(
  st_split_w = 4*extrusion_width,
 
  // screw it
  mount_screw_d = 3.1, mount_screw_l = 20,
  mount_screwhead_d=6, mount_screwhead_h=3,
  idler_screw_d = 3,
  idler_screwhead_d=6, idler_screwhead_h=3,
 
  pf = pushfit_metal,
  pf_shell = max(3*layer_height,3*extrusion_width),
 
  // empty spaces
  idler_travel = 3,				// how far should idler travel when pressed
  idler_clearance=.5,
  pulley_small_d_clearance=.5,
  lever_v_clearance=.7,				// vertical clearance for the lever
  spring_d_clearance=1,
  protrusion_tolerance_h=.5,			// horizontal tolerance for the motor protrusion
  protrusion_tolerance_v=.5,			// vertical tolerance for the motor protrusion
  mount_screw_d_tolerance=.4,
  idler_v_tolerance=.5,
  knob_bore_d_tolerance=.8,
  st_nut_h_tolerance=.2,
  st_nut_d_tolerance=.2,/* TODO: make it st_nut_w_tolerance */
  st_screw_d_tolerance=.5,
  st_split_w_tolerance = .3,
 
  min_z_shell = 4*layer_height,                  // the very minimal shell thickness along z-axis.
  min_xy_shell = 2*extrusion_width,
 
  body_label = "another", body_label_thickness = layer_height,
  knob_label = "another", knob_label_thickness = 2*layer_height, knob_label_size=undef,
 
  what="lever",  // lever|body|knob|springpad|*
  left=false,
  vitamins = true,
  bridges = true,
  debug = false,
 ) {
  fnd = 2*PI; fnr = 2*fnd;
  function lu(m,k) = m[search([k],m)[0]][1];
 
  pulley_d = lu(pulley,"d");
  pulley_h = lu(pulley,"h");
  teeth_elevation = lu(pulley,"fe");
  filament_offset = lu(pulley,"g")+filament_d/2;
  pulley_d_clearance = lu(pulley,"ssrc")*2;
 
+ sp_ch = st_split_w;
+
  idler_filament_offset = filament_path_d/2;
  lever_shell = mount_screwhead_h+0.5;
  lever_thickness=max(spring_d+spring_d_clearance+layer_height*8,idler_h+idler_v_tolerance+2*lever_shell);
  lsd = idler_d-idler_clearance*2; // the diameter of lever thingie
  longwing=(mount_d+mount_screw_d+mount_screw_d_tolerance+spring_d+spring_d_clearance)/2+min_xy_shell;
  shortwing = let(a=mount_d/2,c=(pulley_d+idler_d)/2/sqrt(2))
              sqrt(c*c+pow(a-c,2));
  longwing_travel = idler_travel*longwing/shortwing;
  h_ = (pulley_d+idler_d)/(2*sqrt(2));
  ri = sqrt( pow(h_,2) + pow(mount_d/2-h_,2) );
  spring_dl = idler_travel*longwing/ri;
  // finger and spring support width
  fsw = gearbox_d-(gearbox_d-mount_d)/2-max(spring_lc,longwing_travel+(gearbox_d-mount_d)/2);
 
  mount_min_depth = mounthole_min_depth ? mounthole_min_depth : mounthole_depth-1;
  mount_max_depth = mounthole_max_depth ? mounthole_max_depth : mounthole_depth+1;
  filament_elevation=protrusion_h+pulley_elevation+teeth_elevation;
  ls_z = filament_elevation; // leverspace mid-z
  ls_h = lever_thickness+lever_v_clearance; // leverspace height
  mount_depth = mount_screw_l - (ls_z+ls_h/2+min_z_shell);
  body_h = max(protrusion_h+bore_l,mount_screw_l-mount_depth+mount_screwhead_h+min_z_shell,ls_z*2);
  echo("mount depth",mount_depth);
 
  pf_offset = mount_d/sqrt(2)/2+mount_screw_d/2+min_xy_shell;
 
  module teardrop(r,d,h,center=false,angle=45) {
   dd = d ? d : (2*r);
   $fn = dd*fnd;
   cylinder(d=dd,h=h,center=center);
   if(angle>0) translate([0,0,center?-h/2:0])
    rotate([0,0,angle])
    cube(size=[d/2,d/2,h]);
  }
 
  module mirrorleft() {
   mirror([left?0:1,0,0]) children();
  }
  module place_idler() {
   rotate([0,0,45])
   translate([(pulley_d+idler_d)/2,0,0])
   children();
  }
  module finger_indent(d=lever_thickness,depth/*=1*/,r/*=15*/) {
   if(depth) {
    hh = (-4*pow(depth,2)+pow(d,2))/(8*depth);
    rr = depth+hh;
    translate([0,0,hh]) sphere(r=rr,$fn=fnr*rr);
   }else if(r) {
@@ -313,139 +315,142 @@ module the_extruder(
     rotate([0,0,45])
     rotate_extrude(angle=90,$fn=fnr*(shortwing+(idler_d+idler_clearance)/2))
     square([shortwing+(idler_d+idler_clearance)/2,ls_h]);
     // idler itself
     place_idler()
     cylinder(d=idler_d+idler_clearance,h=ls_h,$fn=fnd*(idler_d+idler_clearance));
     // lever space
     rotate([0,0,45])
     rotate_extrude(angle=-135+max(atan(2*fsw/gearbox_d-1),atan(gearbox_d/mount_d-1)))
     square([gearbox_d/2+1,ls_h]);
    }
 
    // back side cutout
    // XXX: this is somewhat ugly and potentially bugged,
    //      but I want to sleep.
    a0_ = atan(
     (pf_offset+pf_h(pf)+gearbox_d/2)
     /
     (
      pulley_d/2+filament_offset-
      (pf_d(pf)+2*pf_shell)/2/cos(30)
     )
    );
    a0 = -135 + ( (a0_>0) ? a0_ : 180+a0_ );
    a1 = atan((longwing-lever_thickness/2)/(gearbox_d/2));
    translate([0,0,ls_z]) difference() {
     rotate([0,0,-180+a0])
     rotate_extrude(angle=a1-a0)
     translate([0,-ls_h/2])
     square([sqrt(pow(gearbox_d/2,2)+pow(longwing-lever_thickness/2,2))+1,
            ls_h]);
     translate([-mount_d/2,0,0])
     cylinder(d=gearbox_d-mount_d,h=ls_h+2,center=true,$fn=fnd*(gearbox_d-mount_d));
    }//difference translate
    
    // spring tensioner
    translate([-gearbox_d/2,-longwing,ls_z]) rotate([0,-90,0]) {
     mirror([0,0,1]) {
      translate([0,0,st_thickshell])
      hull() for(o=[0,spring_d]) translate([0,-o,0])
      rotate([0,0,30])
      cylinder(d=st_nut_d+st_nut_d_tolerance,h=st_nut_h+st_nut_h_tolerance,$fn=6);
      translate([0,0,-1]) cylinder(d=st_screw_d+st_screw_d_tolerance,h=fsw+2,$fn=fnd*(st_screw_d+st_screw_d_tolerance));
      bigd = spring_d+spring_d_clearance;
      hf = (bigd-st_screw_d-st_screw_d_tolerance)/2;
      translate([0,0,st_thickshell+st_nut_h+st_nut_h_tolerance+st_thinshell-epsilon]) {
       cylinder(d1=st_screw_d+st_screw_d_tolerance,d2=bigd,
        h=hf+epsilon, $fn=fnd*bigd);
-      translate([0,-(st_split_w+st_split_w_tolerance)/2,0])
-      cube(size=[body_h-ls_z+1,st_split_w+st_split_w_tolerance,fsw+1]);
+      translate([0,-(st_split_w+st_split_w_tolerance)/2,0]) hull() {
+       cube(size=[body_h-ls_z-sp_ch-st_split_w_tolerance,st_split_w+st_split_w_tolerance,fsw+1]);
+       translate([0,0,sp_ch+st_split_w_tolerance+1])
+       cube(size=[body_h-ls_z+1,st_split_w+st_split_w_tolerance,fsw+1]);
+      }
      }//translate
      translate([0,0,st_thickshell+st_nut_h+st_nut_h_tolerance+st_thinshell+hf-epsilon])
      cylinder(d=bigd,h=fsw+1,$fn=fnd*bigd);
     }//mirror
    }//translate
 
    // label
    body_label();
 
   }//difference
 
  }//body module
  module body_label() {
   if(body_label) {
    label=body_label;
    label_thickness=body_label_thickness;
    label_len = len(label);
    labelspace = [gearbox_d/2-mount_screwhead_d/2-min_xy_shell,longwing-(mount_screwhead_d-st_split_w-st_split_w_tolerance)/2-2*min_xy_shell];
    translate([0,0,body_h-label_thickness])
    linear_extrude(height=label_thickness+epsilon,convexity=64)
    translate([-mount_screwhead_d/2-min_xy_shell-labelspace.x/2,-longwing+(st_split_w+st_split_w_tolerance)/2+min_xy_shell+labelspace.y/2])
    mirror([left?0:1,0])
    text(text=label,size=labelspace.x/label_len,halign="center",valign="center",font="Arial Black");
   }else sphere(d=epsilon); // to avoid makefile breakage
  }
 
  module springpad() {
   smalld=st_screw_d+st_screw_d_tolerance+min_xy_shell;
   bigd = spring_d+spring_d_clearance/2;
   hf = (bigd-smalld)/2;
   h = max(hf,fsw-st_screw_l+hf);
   translate([-gearbox_d/2+fsw-h,-longwing,filament_elevation])
   rotate([0,90,0]) difference() {
    union() {
     cylinder(d1=smalld,d2=bigd,h=hf,$fn=fnd*bigd);
     translate([0,0,hf-epsilon])
     cylinder(d=bigd,h=h-hf,$fn=fnd*bigd);
     translate([0,0,h])
     sphere(d=spring_d*3/4,$fn=fnd*spring_d*3/4);
     l = body_h-ls_z;
-    w = st_split_w;
+    w = sp_ch;
     hull() translate([0,-st_split_w/2,0]) mirror([1,0,0]) {
      translate([0,0,w])
      cube(size=[l,st_split_w,w]);
      cube(size=[l-w,st_split_w,2*w]);
     }
    }
    translate([0,0,-epsilon])
    cylinder(d=st_screw_d+st_screw_d_tolerance,h=st_screw_l-fsw+h+2*epsilon,$fn=fnd*(st_screw_d+st_screw_d_tolerance));
   }
  }
 
  module knob() {
   ch = knob_indent_d/2;
   knob_bore_l = body_h-protrusion_h-pulley_elevation-pulley_h-knob_v_clearance;
   translate([0,0,body_h+epsilon]) {
    mirror([0,0,1]) translate([0,0,-epsilon]) {
     difference() {
      cylinder(d=pulley_d,h=knob_bore_l,$fn=fnd*pulley_d);
      translate([0,0,-1]) difference() {
       cylinder(d=bore_d+knob_bore_d_tolerance,h=knob_bore_l+2);
       translate([-bore_d/2-1,bore_dd-bore_d/2+knob_bore_d_tolerance/2,-1])
       cube([bore_d+2,bore_d/2,knob_bore_l+4]);
      }
     }
    }
    difference() {
     hull() {
      cylinder(d=gearbox_d-2*ch,h=knob_h,$fn=fnd*gearbox_d);
      translate([0,0,ch])
      cylinder(d=gearbox_d,h=knob_h-2*ch,$fn=fnd*gearbox_d);
     }
     for(a=[0:360/knob_indents:359]) rotate([0,0,a])
      translate([0,gearbox_d/2,-1])
      cylinder(d=knob_indent_d,h=knob_h+2,$fn=fnd*knob_indent_d);
     translate([0,0,-body_h-epsilon]) knob_label();
    }
   }
  }//knob module
  module knob_label() {
   if(knob_label) {
    ll = len(knob_label);
    lsl = gearbox_d-knob_indent_d;
    ts = knob_label_size?knob_label_size:min(lsl/ll,gearbox_d/4);
    translate([0,0,body_h+epsilon+knob_h-knob_label_thickness])
    linear_extrude(height=knob_label_thickness+epsilon,convexity=64)
    mirror([left?0:1,0])
    text(text=knob_label,size=ts,halign="center",valign="center",font="Arial Black");
   }else sphere(d=epsilon); // to avoid makefile breakage