Escapement demo
ruste...@prototribe.net
I've printed it at 30mm/sec and the wheel comes out ~1mm smaller than designed. Printing at 40mm/second and the wheel comes out ~4mm smaller than designed so print speed is very important here. The slower the better. Here are a few of the other settings that i'm using:
- zero extra shells
- 0.36mm layer height (.4mm nozzle)
- 1.515 perimeter (and infill) width over thickness
The slower and narrower (~0.5mm wide) the extrusion the better it seems. I'd be curious to see what others get as a result and how well they feel the mechanism works for them.
Also needed are 2 M3 screws, perhaps ~40-50 mm long. Screw them in from the back and the pieces can be readily replaced by different versions. To loosen up the holes in the escapement wheel and pendulum screw one of the long M3 screws in till the non-threaded part is reached. The force the screw all the way through. Then force it all the way back even across the threaded part. This lets the screw itself file down the holes to the perfect size. Repeat until the pieces rotate freely but do not wobble too much. If the holes are too tight the extuder may be extuding too much plastic. An alternate route for filing the holes is to mount the M3 screw into a drill and use it like a drill bit screwing it into the hole first, then attempting to go against the threading, repeating as necessary.
I'll try to upload some video soon.
Regards,
Rustedrobot
# GPL v2 or CC BY-NC-SA 3.0
include <involute_gears.scad>;
include <../interlocpanellib/InterlocPanelLib.scad>;
include <../ParametricRatchetLib/RatchetLib.scad>;
include <spiffsans.scad>;
//cube([100,100,1]);
//cylinder(r=1.4, h=20, center=true);
dist=sqrt(pow(35,2) + pow(35,2));
escapement_dist=sqrt(pow(35,2) + pow(35,2));
rotate([0,0,90]) {
union() {
translate([-77.75,0,12]) {
rotate([-180,0,-180]) {
rotate([0,0,6]) {
escapement_gear();
}
translate([escapement_dist,0,0]) {
rotate([0,0,0]) {
mirror([0,1,0]) {
escapement();
}
}
}
escapement_test_block();
rotate(0,0,45) {
translate([170.6,0,0]) {
// pendulum_extension();
}
translate([170.6,25,0]) {
// pendulum_extension();
}
translate([170.6,50,0]) {
// pendulum_extension();
}
translate([170.6,75,0]) {
// pendulum_extension();
}
}
}
}
translate([0,-500,0]) {
// cube([1000,1000,1000], center=true);
}
}
}
module escapement_test_block() {
translate([25,0,25]) {
mirror([0,0,1]) {
difference() {
cube([75,20,20], center=true);
translate([escapement_dist/2,0,0]) {
cylinder(r=3, h=50, center=true);
}
translate([-escapement_dist/2,0,0]) {
cylinder(r=3, h=50, center=true);
}
}
translate([escapement_dist/2,0,-10]) {
support(28, 20);
}
translate([-escapement_dist/2,0,-10]) {
support(24, 20);
}
}
}
}
module support(height=30, outer_diameter=10, inner_diameter=3, bearing_height=10) {
translate([0,0,height/2]) {
difference() {
cylinder(r=outer_diameter/2, h=height, center=true, $fn=6);
cylinder(r=inner_diameter+1, h=height-bearing_height*2, center=true, $fn=24);
translate([0,0,,(height/2-bearing_height/2)]) {
innerbearing(bearing_height);
}
translate([0,0,-(height/2-bearing_height/2)]) {
innerbearing(bearing_height);
}
}
}
}
module smallkey(border=0, height=4) {
difference() {
cube([7+border*2,7+border*2,height], center=true);
translate([22,19,0]) {
rotate([0,0,20]) {
cube([50-border*2,50-border*2,10], center=true);
}
}
translate([-22,19,0]) {
rotate([0,0,-20]) {
cube([50-border*2,50-border*2,10], center=true);
}
}
}
}
// escapement gear
module escapement_gear() {
difference() {
union() {
translate([0,0,7]) {
rotate([0,0,90]) {
wgear(9, 6);
}
}
cylinder(r=12, h=4, center=true);
translate([0,0,3]) {
cylinder(r2=8.5, r1=12, h=2, center=true);
}
cylinder(r=25, h=4, center=true, $fn=42);
mirror([0,1,0]) {
for (i=[0:29]) {
rotate([0,0,12*i]) {
translate([-30,0,0]) {
rotate([0,0,180]) {
tooth();
}
}
}
}
}
}
translate([0,0,4]) {
innerbearing(12);
}
}
}
module tooth() {
translate([-0.4,-4.12,0]) {
difference() {
translate([-1,0,0]) {
cube([12,10,4], center=true);
}
translate([5,5,0]) {
rotate([0,0,-25]) {
cube([20,10,5], center=true);
}
}
translate([5,-6.1,0]) {
rotate([0,0,-15]) {
cube([30,10,5], center=true);
}
}
}
}
}
module escapement() {
dist=sqrt(pow(35,2) + pow(35,2));
// compensate for printing inaccuracies and corner rounding
// faceadjust_a=0.2;
// faceadjust_b=0.2;
// faceadjust_a=-0.6;
// faceadjust_b=-0.8;
faceadjust_a=-0.1;
faceadjust_b=-0.4;
facets=69;
// translate([dist,0,0]) {
difference() {
union() {
difference() {
// cylinder(r=37, h=4, center=true, $fn=facets); // circular design
cylinder(r=35.5, h=4, center=true, $fn=facets); // equidistant lock
cylinder(r=32.5, h=5, center=true, $fn=facets);
translate([0,-40,0]) {
cube([80,80,80], center=true);
}
// clip circle
translate([35.7,50,0]) {
rotate([0,0,24]) {
cube([100,100,10], center=true);
}
}
// cut palette faces
translate([-74.8-faceadjust_a,22,0]) {
rotate([0,0,7]) {
cube([100,100,10], center=true);
}
}
}
difference() {
// cylinder(r=38.5, h=4, center=true, $fn=facets);
cylinder(r=38.2, h=4, center=true, $fn=facets);
// cylinder(r=33, h=5, center=true, $fn=facets); // circular design
// cylinder(r=35.5, h=5, center=true, $fn=facets); // equidistant lock
cylinder(r=35.2, h=5, center=true, $fn=facets); // equidistant lock
translate([0,30,0]) {
cube([80,80,80], center=true);
}
// clip circle
translate([35.7,-50,0]) {
rotate([0,0,-24]) {
cube([100,100,10], center=true);
}
}
translate([-26.9,-14.55+faceadjust_b,0]) {
rotate([0,0,7]) {
color([.3,.8,.5, .4]) cube([100,20,10], center=true);
}
}
}
// center
translate([0,0,2]) {
cylinder(r=5, h=8, center=true, $fn=24);
}
rotate([0,0,24]) {
translate([0,16.5,0]) {
cube([6,34,4], center=true);
}
}
rotate([0,0,156]) {
translate([0,16.5,0]) {
cube([6,38,4], center=true);
}
}
rotate([0,0,-90]) {
translate([0,26.5,0]) {
cube([8,60,4], center=true);
}
}
translate([64,0,0]) {
difference() {
rotate([0,0,90]) {
key(0,4);
}
translate([10,0,0]) {
rotate([0,0,-90]) {
smallkey(0.1,5);
}
}
}
}
}
translate([0,0,2]) {
innerbearing(8);
}
}
// }
}
module pendulum_extension() {
translate([-37,0,0]) {
difference() {
union() {
rotate([0,0,-90]) {
key(0,4);
translate([0,-10,0]) {
smallkey();
}
}
}
translate([-1,0,0]) {
cylinder(r=3, h=10, center=true);
}
}
}
rotate([0,0,-90]) {
translate([0,0,0]) {
cube([8,60,4], center=true);
}
}
translate([37,0,0]) {
difference() {
rotate([0,0,90]) {
key(0,4);
}
translate([10,0,0]) {
rotate([0,0,-90]) {
smallkey(0.1,5);
}
}
translate([1,0,0]) {
cylinder(r=3, h=10, center=true);
}
}
}
}
module wgear(teeth=20, height=4, circles=6, spokes=0) {
circular_pitch = 200;
backlash_num = 0.7;
zgear_radius = teeth * circular_pitch / 360;
ztooth_height = (zgear_radius * sin (360 / (4 * teeth)) - backlash_num / 4) * 2;
difference() {
zgear(teeth, height, circles, circular_pitch, height, backlash_num);
}
}
module innerbearing(height) {
cylinder(r=1.6, h=height+1, center=true, $fn=24);
translate([0,0,-(height/2.6)]) {
cylinder(r1=3, r2=0, h=height/2+0.1, center=true, $fn=24);
}
translate([0,0,height/2.6]) {
cylinder(r2=3, r1=0, h=height/2+0.1, center=true, $fn=24);
}
translate([0,0,height/4]) {
cylinder(r1=3, r2=0, h=height/2+0.01, center=true, $fn=24);
}
translate([0,0,-(height/4)]) {
cylinder(r2=3, r1=0, h=height/2+0.01, center=true, $fn=24);
}
}
module zgear(teeth=60, height=4, circles=6, circular_pitch=300, height=5, backlash=0) {
//twist=30;
twist=0;
pressure_angle=14.5;
gear (number_of_teeth=teeth,
circular_pitch = circular_pitch,
pressure_angle = pressure_angle,
clearance = 0.3,
gear_thickness = height/2,
rim_thickness = height/2,
rim_width = 0,
hub_thickness = height/2,
hub_diameter = 0,
bore_diameter = 0,
circles = circles,
twist = twist/teeth,
backlash = backlash);
mirror([0,0,1])
gear (number_of_teeth=teeth,
circular_pitch=circular_pitch,
pressure_angle=pressure_angle,
clearance = 0.3,
gear_thickness = height/2,
rim_thickness = height/2,
rim_width = 20,
hub_thickness = height/2,
hub_diameter = 0,
bore_diameter = 0,
circles = circles,
twist = twist/teeth,
backlash = backlash);
}
Mathieu Glachant
On Tuesday, March 13, 2012, <ruste...@prototribe.net> wrote:
> One correction. I was actually using 0.3mm layer height.
>
> On 03/12/2012 11:14 PM, ruste...@prototribe.net wrote:
>
> Below is the code for the escapement geometry that currently works for me. The clock ticks reliably with a 5lb weight hanging off the minute gear and appears to be accurate to within ~5 minutes/day currently (without tuning of pendulum). The gears and body are still in flux, but i'm considering the escapement mechanism "finished" at least until all the other pieces are addressed. I've stripped all but the basics needed to generate the geometry (and the backing gear on the escapement wheel).
>