grip the ball better in the caster standoff

[challenge-bot] / 3d-printables / caster-standoff.scad

diff --git a/3d-printables/caster-standoff.scad b/3d-printables/caster-standoff.scad
index 2b2bf571a0a34f4ea6aa1dc90e101a74ddf971d3..69147814e7c8aa86f0d8e9d8bd42da5392966778 100644 (file)
--- a/3d-printables/caster-standoff.scad
+++ b/3d-printables/caster-standoff.scad
@@ -4,21 +4,29 @@
 // https://gitorious.org/ozzloy/challenge-bot
 // https://github.com/waynegramlich/challenge-bot
 
+use <oshw.scad>
+
 // use 10 ish for development, 60 or so for printing
 $fn = 60;
 
 /* measured with calipers */
-ball_diameter = 12.7 + 0.75; // extra bit added for printing imprecision
+ball_diameter = 12.7 + 0.80; // extra bit added for printing imprecision
 ball_radius = ball_diameter / 2;
 
+standoff_height = 60; // kyle eyeballed
+
+gap = 2;
 wall_thickness = 1;
-holder_height = (25 / 32) * ball_diameter + wall_thickness;
+holder_floor = 3;
+holder_arms_length = 20;
+holder_height =
+  holder_floor + holder_arms_length + (11 / 16) * ball_diameter;
 
 holder_radius = ball_radius + wall_thickness;
 holder_diameter = holder_radius * 2;
 
 standoff_radius = holder_radius; // 0.580 / 2 inches from spec sheet
-standoff_height = 48; // eyeballed
+standoff_lower_portion_height = standoff_height - holder_height;
 
 // eyeballed caster flange height, (0.580/5) inches, times 2 to be stronger
 caster_flange_height = 5;
@@ -26,21 +34,24 @@ caster_flange_width = 20.32;  // 0.800 inches
 caster_flange_screw_radius = 2.286 / 2;  // 0.090 inches
 caster_flange_screw_length = 8; // eyeballed
 
-deck_grid_width = 25.4; // measured center to center on grid on pegboard
+deck_pitch = 25.4; // measured center to center on grid on pegboard
 deck_flange_height = 2.9464;
 deck_flange_screw_radius = 3.556 / 2;  // For #6 machine screws
-deck_flange_radius = (deck_grid_width) / 2 + deck_flange_screw_radius + 3;
+deck_flange_radius = (deck_pitch) / 2 + deck_flange_screw_radius + 3;
 
 module deck_flange(){
+  deck_pitch_diagonal = sqrt(2 * pow(deck_pitch, 2));
   difference(){
-    cylinder(h = deck_flange_height, r = deck_flange_radius);
+    scale([0.35, 0.35, 1]){
+      linear_extrude(height = deck_flange_height){
+        oshw();}}
     for(ii = [-1, 1]){
-      translate([deck_grid_width / 2 * ii, 0, -.1])
-        cylinder(h = deck_flange_height * 1.1,
-                 r = deck_flange_screw_radius);
-      translate([0, deck_grid_width / 2 * ii, -.1])
+      translate([deck_pitch_diagonal / 2 * ii, 0, -.1])
         cylinder(h = deck_flange_height * 1.1,
-        r = deck_flange_screw_radius);}}}
+                 r = deck_flange_screw_radius);}
+    translate([0, deck_pitch_diagonal / 2, -.1])
+      cylinder(h = deck_flange_height * 1.1,
+               r = deck_flange_screw_radius);}}
 
 module deck_flange_reinforcement(){
   translate([-deck_flange_radius,
@@ -55,25 +66,34 @@ module deck_flange_reinforcement(){
                 deck_flange_radius]);}}}}}
 
 module ball_holder(){
-  gap = wall_thickness * 4;
-  floor = wall_thickness;
   difference (){
-    cylinder(r = holder_radius, h = holder_height + floor);
-    translate([0, 0, ball_radius + wall_thickness + floor]){
+    union(){
+      cylinder(r = holder_radius, h = holder_height);
+      translate([0, 0, holder_arms_length]){
+        cylinder(r1 = holder_radius,
+                 r2 = holder_radius + wall_thickness,
+                 h = wall_thickness);
+        translate([0, 0, wall_thickness]){
+          cylinder(r = wall_thickness + holder_radius,
+                   h = holder_height
+                       - holder_arms_length
+                       - wall_thickness); }}}
+    translate([0, 0, ball_radius + holder_floor + holder_arms_length]){
       sphere(r = ball_radius);}
-    translate([0, 0, holder_height / 2 + wall_thickness + floor]){
-      cube([holder_diameter + 0.1, gap, holder_height],
+    translate([0, 0, holder_floor + (holder_height - holder_floor) / 2 + 0.5]){
+      cube([holder_diameter + wall_thickness * 2 + 0.1,
+            gap,
+            holder_height - holder_floor + 0.1],
            center = true);}}}
 
 module caster_standoff(){
-  cylinder(h = standoff_height,
+  cylinder(h = standoff_lower_portion_height,
            r = standoff_radius);
   deck_flange();
   for(ii = [0:3]){
     rotate([0, 0, 45 + 90 * ii])
       deck_flange_reinforcement();}
-  translate([0, 0, standoff_height]){
+  translate([0, 0, standoff_lower_portion_height]){
     ball_holder();}}
 
-//caster_standoff();
-ball_holder();
+caster_standoff();