Finished end links.

This commit is contained in:
Chris Palmer 2020-11-17 16:14:25 +00:00
parent 9944aab73e
commit 4dc83d62cb
3 changed files with 164 additions and 90 deletions

View File

@ -20,7 +20,7 @@
//
//! Parametric cable drag chain to limit the bend radius of a cable run.
//!
//! Each link has a maximum bend angle, so the mininium radius is proportional to the link length.
//! Each link has a maximum bend angle of 45°, so the mininium radius is proportional to the link length.
//!
//! The travel prpoery is how far it can move in each direction, i.e. half the maximum travel if the chain is mounted in the middle of the travel.
//
@ -29,12 +29,14 @@ include <../core.scad>
use <../utils/horiholes.scad>
use <../utils/maths.scad>
function drag_chain_name(type) = type[0]; //! The name to allow more than one in a project
function drag_chain_size(type) = type[1]; //! The internal size and link length
function drag_chain_travel(type)= type[2]; //! X travel
function drag_chain_wall(type) = type[3]; //! Side wall thickness
function drag_chain_bwall(type) = type[4]; //! Bottom wall
function drag_chain_twall(type) = type[5]; //! Top wall
function drag_chain_name(type) = type[0]; //! The name to allow more than one in a project
function drag_chain_size(type) = type[1]; //! The internal size and link length
function drag_chain_travel(type) = type[2]; //! X travel
function drag_chain_wall(type) = type[3]; //! Side wall thickness
function drag_chain_bwall(type) = type[4]; //! Bottom wall
function drag_chain_twall(type) = type[5]; //! Top wall
function drag_chain_screw(type) = type[6]; //! Mounting screw for the ends
function drag_chain_screw_lists(type) = type[7]; //! Two lists of four bools to say which screws positions are used
function drag_chain_radius(type) = //! The bend radius at the pivot centres
let(s = drag_chain_size(type))
@ -44,8 +46,8 @@ function drag_chain_z(type) = //! Outside dimension of a 180 bend
let(os = drag_chain_outer_size(type), s = drag_chain_size(type))
2 * drag_chain_radius(type) + os.z;
function drag_chain(name, size, travel, wall = 1.6, bwall = 1.5, twall = 1.5) = //! Constructor
[name, size, travel, wall, bwall, twall];
function drag_chain(name, size, travel, wall = 1.6, bwall = 1.5, twall = 1.5, screw = M2_cap_screw, screw_lists = [[1,0,0,1],[1,0,0,1]]) = //! Constructor
[name, size, travel, wall, bwall, twall, screw, screw_lists];
clearance = 0.1;
@ -53,8 +55,53 @@ function drag_chain_outer_size(type) = //! Link outer dimensions
let(s = drag_chain_size(type), z = s.z + drag_chain_bwall(type) + drag_chain_twall(type))
[s.x + z, s.y + 4 * drag_chain_wall(type) + 2 * clearance, z];
function screw_lug_radius(screw) = //! Radius if a screw lug
corrected_radius(screw_clearance_radius(screw)) + 3.1 * extrusion_width;
module drag_chain_link(type, start = false, end = false) {
module screw_lug(screw, h = 0) //! Create a D shaped lug for a screw
extrude_if(h, center = false)
difference() {
r = screw_lug_radius(screw);
hull() {
circle4n(r);
translate([-r, -r])
square([2 * r, eps]);
}
poly_circle(screw_clearance_radius(screw));
}
function bool2int(b) = b ? 1 : 0;
module drag_chain_screw_positions(type, end) {//! Place children at the screw positions, end = 0 for the start, 1 for the end
r = screw_lug_radius(drag_chain_screw(type));
s = drag_chain_size(type);
os = drag_chain_outer_size(type);
R = os.z / 2;
x0 = end ? R + norm([drag_chain_cam_x(type), R - drag_chain_twall(type)]) + clearance + r : r;
x1 = end ? os.x - r : os.x - 2 * R - clearance - r;
for(i = [0 : 3]) {
x = i % 2;
y = bool2int(i > 1);
if(drag_chain_screw_lists(type)[bool2int(end)][i])
translate([(x0 + x1) / 2, 0])
mirror([x, 0])
mirror([0, y])
translate([(x1 - x0) / 2, s.y / 2 + r])
children();
}
}
function drag_chain_cam_x(type) = // how far the cam sticks out
let(s = drag_chain_size(type),
r = drag_chain_outer_size(type).z / 2,
wall = drag_chain_wall(type),
cam_r = s.x - 2 * clearance - wall - r, // inner_x_normal - clearance - r
twall = drag_chain_twall(type)
) min(sqrt(max(sqr(cam_r) - sqr(r - twall), 0)), r);
module drag_chain_link(type, start = false, end = false) { //! One link of the chain, special case for start and end
stl(str(drag_chain_name(type), "_drag_chain_link", start ? "_start" : end ? "_end" : ""));
s = drag_chain_size(type);
@ -64,96 +111,115 @@ module drag_chain_link(type, start = false, end = false) {
os = drag_chain_outer_size(type);
r = os.z / 2;
pin_r = r / 2;
inner_x_normal = s.x - wall;
inner_x = start ? 0 : s.x - inner_x_normal;
socket_x = r;
pin_x = socket_x + s.x;
outer_normal_x = pin_x - r - clearance; // s.x - clearance
outer_end_x = end ? os.x : outer_normal_x;
inner_x = start ? 0 : outer_normal_x - wall; // s.x - clearance - wall
roof_x_normal = 2 * r - twall;
roof_x = start ? 0 : roof_x_normal;
floor_x = start ? 0 : 2 * r;
cam_r = inner_x_normal - clearance - r;
cam_x = min(sqrt(max(sqr(cam_r) - sqr(r - twall), 0)), r);
outer_end_x = end ? os.x : s.x - clearance;
cam_x = drag_chain_cam_x(type);
assert(r + norm([drag_chain_cam_x(type), r - drag_chain_twall(type)]) + clearance <= inner_x || start, "Link must be longer");
for(side = [-1, 1])
rotate([90, 0, 0]) {
// Outer cheeks
translate_z(side * (os.y / 2 - wall / 2))
linear_extrude(wall, center = true)
difference() {
hull() {
if(start)
translate([floor_x, 0])
square([eps, os.z]);
else
translate([r, r])
rotate(180)
teardrop(r = r, h = 0);
translate([outer_end_x - eps, 0])
square([eps, os.z]);
}
if(!start)
translate([r, r])
horihole(pin_r, r);
}
// Inner cheeks
translate_z(side * (s.y / 2 + wall / 2))
linear_extrude(wall, center = true)
difference() {
union() {
hull() {
if(!end) {
translate([s.x + r, r])
rotate(180)
teardrop(r = r, h = 0);
translate([s.x + r, twall])
square([cam_x, eps]);
}
else
translate([s.x + 2 * r - eps, 0])
difference() {
union() {
for(side = [-1, 1])
rotate([90, 0, 0]) {
// Outer cheeks
translate_z(side * (os.y / 2 - wall / 2))
linear_extrude(wall, center = true)
difference() {
hull() {
if(start)
square([eps, os.z]);
else
translate([socket_x, r])
rotate(180)
teardrop(r = r, h = 0);
translate([inner_x, 0])
square([eps, os.z]);
translate([outer_end_x - eps, 0])
square([eps, os.z]);
}
if(!start)
translate([socket_x, r])
horihole(pin_r, r);
}
}
// Cutout for top wall
if(!end)
intersection() {
translate([s.x, 0])
square([3 * r, twall]); // When straight
// Inner cheeks
translate_z(side * (s.y / 2 + wall / 2))
linear_extrude(wall, center = true)
difference() {
union() {
hull() {
if(!end) {
translate([pin_x, r])
rotate(180)
teardrop(r = r, h = 0);
translate([s.x + r, r])
rotate(-45)
translate([-r + roof_x_normal, -r - twall]) // When bent fully
square(os.z);
translate([pin_x, twall])
square([cam_x, eps]);
}
else
translate([os.x - eps, 0])
square([eps, os.z]);
translate([inner_x, 0])
square([eps, os.z]);
}
}
// Cutout for top wall
if(!end)
intersection() {
translate([pin_x - r, 0])
square([3 * r, twall]); // When straight
translate([pin_x, r])
rotate(-45)
translate([-r + roof_x_normal, -r - twall]) // When bent fully
square(os.z);
}
}
}
// Pin
if(!end)
translate([s.x + r, r, side * (s.y / 2 + wall + clearance)])
horicylinder(r = pin_r, z = r, h = 2 * wall);
// Pin
if(!end)
translate([pin_x, r, side * (s.y / 2 + wall + clearance)])
horicylinder(r = pin_r, z = r, h = 2 * wall);
// Cheek joint
translate([inner_x, 0, side * (s.y / 2 + wall) - 0.5])
cube([outer_end_x - inner_x, os.z, 1]);
// Cheek joint
translate([inner_x, 0, side * (s.y / 2 + wall) - 0.5])
cube([outer_end_x - inner_x, os.z, 1]);
}
// Roof, actually the floor when printed
roof_end = end ? s.x + 2 * r : s.x + r - twall - clearance;
translate([roof_x, -s.y / 2 - 0.5])
cube([roof_end - roof_x , s.y + 1, twall]);
translate([roof_x, -os.y / 2 + 0.5])
cube([s.x - clearance - roof_x, os.y - 1, twall]);
// Floor, actually the roof when printed
floor_end = end ? s.x + 2 * r : s.x + r;
translate([floor_x, -s.y / 2 - wall, os.z - bwall])
cube([floor_end - floor_x, s.y + 2 * wall, bwall]);
translate([floor_x, -os.y / 2 + 0.5, os.z - bwall])
cube([s.x - floor_x - clearance, os.y -1, bwall]);
if(start || end)
drag_chain_screw_positions(type, end)
screw_lug(drag_chain_screw(type), os.z);
}
if(start || end)
translate_z(-eps)
drag_chain_screw_positions(type, end)
poly_cylinder(r = screw_clearance_radius(drag_chain_screw(type)), h = os.z + 2 * eps, center = false);
// Roof, actually the floor when printed
roof_end = end ? s.x + 2 * r : s.x + r - twall - clearance;
translate([roof_x, -s.y / 2 - wall])
cube([roof_end - roof_x , s.y + 2 * wall, twall]);
translate([roof_x, -os.y / 2 + 0.5])
cube([s.x - clearance - roof_x, os.y - 1, twall]);
// Base, actually the roof when printed
floor_end = end ? s.x + 2 * r : s.x + r;
translate([floor_x, -s.y / 2 - wall, os.z - bwall])
cube([floor_end - floor_x, s.y + 2 * wall, bwall]);
translate([floor_x, -os.y / 2 + 0.5, os.z - bwall])
cube([s.x - floor_x - clearance, os.y -1, bwall]);
}
if(show_supports() && !end) {
for(side = [-1, 1]) {
@ -173,6 +239,8 @@ module drag_chain_link(type, start = false, end = false) {
}
}
//! 1. Remove the support material from the links with side cutters.
//! 1. Clip the links together with the special ones at the ends.
module drag_chain_assembly(type, pos = 0) { //! Drag chain assembly
s = drag_chain_size(type);
r = drag_chain_radius(type);

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@ -4546,7 +4546,7 @@ Door latch for 6mm acrylic door for 3D printer. See [door_hinge](#door_hinge).
## Drag_chain
Parametric cable drag chain to limit the bend radius of a cable run.
Each link has a maximum bend angle, so the mininium radius is proportional to the link length.
Each link has a maximum bend angle of 45&deg;, so the mininium radius is proportional to the link length.
The travel prpoery is how far it can move in each direction, i.e. half the maximum travel if the chain is mounted in the middle of the travel.
@ -4560,6 +4560,8 @@ The travel prpoery is how far it can move in each direction, i.e. half the maxim
|:--- |:--- |
| ```drag_chain_bwall(type)``` | Bottom wall |
| ```drag_chain_name(type)``` | The name to allow more than one in a project |
| ```drag_chain_screw(type)``` | Mounting screw for the ends |
| ```drag_chain_screw_lists(type)``` | Two lists of four bools to say which screws positions are used |
| ```drag_chain_size(type)``` | The internal size and link length |
| ```drag_chain_travel(type)``` | X travel |
| ```drag_chain_twall(type)``` | Top wall |
@ -4568,15 +4570,19 @@ The travel prpoery is how far it can move in each direction, i.e. half the maxim
### Functions
| Function | Description |
|:--- |:--- |
| ```drag_chain(name, size, travel, wall = 1.6, bwall = 1.5, twall = 1.5)``` | Constructor |
| ```drag_chain(name, size, travel, wall = 1.6, bwall = 1.5, twall = 1.5, screw = M2_cap_screw, screw_lists = [[1,0,0,1],[1,0,0,1]])``` | Constructor |
| ```drag_chain_outer_size(type)``` | Link outer dimensions |
| ```drag_chain_radius(type)``` | The bend radius at the pivot centres |
| ```drag_chain_z(type)``` | Outside dimension of a 180 bend |
| ```screw_lug_radius(screw)``` | Radius if a screw lug |
### Modules
| Module | Description |
|:--- |:--- |
| ```drag_chain_assembly(type, pos = 0)``` | Drag chain assembly |
| ```drag_chain_link(type, start = false, end = false)``` | One link of the chain, special case for start and end |
| ```drag_chain_screw_positions(type, end)``` | Place children at the screw positions, end = 0 for the start, 1 for the end |
| ```screw_lug(screw, h = 0)``` | Create a D shaped lug for a screw |
![drag_chain](tests/png/drag_chain.png)

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