diff --git a/printed/drag_chain.scad b/printed/drag_chain.scad
index 237e58d..49447da 100644
--- a/printed/drag_chain.scad
+++ b/printed/drag_chain.scad
@@ -54,8 +54,8 @@ function drag_chain_outer_size(type) = //! Link outer dimensions
[s.x + z, s.y + 4 * drag_chain_wall(type) + 2 * clearance, z];
-module drag_chain_link(type) {
- stl(str(drag_chain_name(type), "_drag_chain_link"));
+module drag_chain_link(type, start = false, end = false) {
+ stl(str(drag_chain_name(type), "_drag_chain_link", start ? "_start" : end ? "_end" : ""));
s = drag_chain_size(type);
wall = drag_chain_wall(type);
@@ -64,11 +64,14 @@ module drag_chain_link(type) {
os = drag_chain_outer_size(type);
r = os.z / 2;
pin_r = r / 2;
- inner_x = s.x - wall;
- roof_x = 2 * r - twall;
- floor_x = 2 * r;
- cam_r = inner_x - clearance - r;
+ inner_x_normal = s.x - wall;
+ inner_x = start ? 0 : s.x - inner_x_normal;
+ 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;
for(side = [-1, 1])
rotate([90, 0, 0]) {
@@ -77,15 +80,20 @@ module drag_chain_link(type) {
linear_extrude(wall, center = true)
difference() {
hull() {
- translate([r, r])
- rotate(180)
- teardrop(r = r, h = 0);
+ if(start)
+ translate([floor_x, 0])
+ square([eps, os.z]);
+ else
+ translate([r, r])
+ rotate(180)
+ teardrop(r = r, h = 0);
- translate([s.x - clearance - eps, 0])
+ translate([outer_end_x - eps, 0])
square([eps, os.z]);
}
- translate([r, r])
- horihole(pin_r, r);
+ if(!start)
+ translate([r, r])
+ horihole(pin_r, r);
}
// Inner cheeks
translate_z(side * (s.y / 2 + wall / 2))
@@ -93,52 +101,61 @@ module drag_chain_link(type) {
difference() {
union() {
hull() {
- translate([s.x + r, r])
- rotate(180)
- teardrop(r = r, h = 0);
+ if(!end) {
+ translate([s.x + r, r])
+ rotate(180)
+ teardrop(r = r, h = 0);
- translate([s.x + r, twall])
- square([cam_x, eps]);
+ translate([s.x + r, twall])
+ square([cam_x, eps]);
+ }
+ else
+ translate([s.x + 2 * r - eps, 0])
+ square([eps, os.z]);
translate([inner_x, 0])
square([eps, os.z]);
}
}
// Cutout for top wall
- intersection() {
- translate([s.x, 0])
- square([3 * r, twall]); // When straight
+ if(!end)
+ intersection() {
+ translate([s.x, 0])
+ square([3 * r, twall]); // When straight
- translate([s.x + r, r])
- rotate(-45)
- translate([-r + roof_x, -r - twall]) // When bent fully
- square(os.z);
- }
+ translate([s.x + r, r])
+ rotate(-45)
+ translate([-r + roof_x_normal, -r - twall]) // When bent fully
+ square(os.z);
+ }
}
- // Pin
- translate([s.x + r, r, side * (s.y / 2 + wall + clearance)])
- horicylinder(r = pin_r, z = r, h = 2 * wall);
+ // Pin
+ if(!end)
+ translate([s.x + r, 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([s.x - clearance - 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
- translate([roof_x, -s.y / 2 - 0.5])
- cube([s.x + r - roof_x - twall - clearance, s.y + 1, twall]);
+ // 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 - roof_x - clearance, os.y - 1, twall]);
+ cube([s.x - clearance - roof_x, os.y - 1, twall]);
- // Base
- translate([floor_x, -s.y / 2 - 0.5, os.z - bwall])
- cube([s.x + r - floor_x, s.y + 1, bwall]);
+ // 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()) {
+ if(show_supports() && !end) {
for(side = [-1, 1]) {
w = 2.1 * extrusion_width;
translate([s.x + r + cam_x - w / 2, side * (s.y / 2 + wall / 2), twall / 2])
@@ -167,13 +184,7 @@ module drag_chain_assembly(type, pos = 0) { //! Drag chain assembly
zb = z / 2; // z of bottom track
c = [actual_travel / 2 + pos / 2, 0, r + zb]; // centre of bend
- module link(n) // Position and colour link with origin at the hinge hole
- translate([-z / 2, 0, -z / 2])
- stl_colour(n % 2 ? pp1_colour : pp2_colour)
- drag_chain_link(type);
-
-
- points = [ // Calculate lits of hinge points
+ points = [ // Calculate list of hinge points
for(i = 0, p = [0, 0, z / 2 + 2 * r]; i < links + 5;
i = i + 1,
dx = p.z > c.z ? s.x : -s.x,
@@ -183,10 +194,24 @@ module drag_chain_assembly(type, pos = 0) { //! Drag chain assembly
: q) // Circular section
p
];
+ npoints = len(points);
- assembly(str(drag_chain_name(type), "_drag_chain"))
- for(i = [0 : len(points) - 2]) let(v = points[i+1] - points[i])
+ module link(n) // Position and colour link with origin at the hinge hole
+ translate([-z / 2, 0, -z / 2])
+ stl_colour(n % 2 ? pp1_colour : pp2_colour)
+ drag_chain_link(type, start = n == -1, end = n == npoints - 1);
+
+ assembly(str(drag_chain_name(type), "_drag_chain")) {
+ for(i = [0 : npoints - 2]) let(v = points[i+1] - points[i])
translate(points[i])
rotate([0, -atan2(v.z, v.x), 0])
link(i);
+
+ translate(points[0] - [s.x, 0, 0])
+ link(-1);
+
+ translate(points[npoints - 1])
+ hflip()
+ link(npoints - 1);
+ }
}
diff --git a/readme.md b/readme.md
index 40a6cb2..56dfe99 100644
--- a/readme.md
+++ b/readme.md
@@ -28,20 +28,20 @@ See [usage](docs/usage.md) for requirements, installation instructions and a usa
| Bulldogs | Leadnuts | SK_brackets | Corner_block | Gears | Sphere |
| Buttons | Light_strips | SMDs | Door_hinge | Hanging_hole | Teardrops |
| Cable_strips | Linear_bearings | SSRs | Door_latch | Horiholes | |
-| Cameras | Magnets | Screws | Fan_guard | Layout | |
-| Circlips | Mains_sockets | Sealing_strip | Fixing_block | Maths | |
-| Components | Microswitches | Shaft_couplings | Flat_hinge | Offset | |
-| DIP | Microview | Sheets | Foot | Quadrant | |
-| D_connectors | Modules | Spades | Handle | Round | |
-| Displays | Nuts | Spools | PCB_mount | Rounded_cylinder | |
-| Extrusion_brackets | O_ring | Springs | PSU_shroud | Rounded_polygon | |
-| Extrusions | Opengrab | Stepper_motors | Printed_box | Sector | |
-| Fans | PCB | Swiss_clips | Ribbon_clamp | Sweep | |
-| Fuseholder | PCBs | Toggles | SSR_shroud | Thread | |
-| Geared_steppers | PSUs | Transformers | Screw_knob | Tube | |
-| Green_terminals | Panel_meters | Tubings | Socket_box | | |
-| Hot_ends | Pillars | Variacs | Strap_handle | | |
-| Hygrometer | Pin_headers | Veroboard | | | |
+| Cameras | Magnets | Screws | Drag_chain | Layout | |
+| Circlips | Mains_sockets | Sealing_strip | Fan_guard | Maths | |
+| Components | Microswitches | Shaft_couplings | Fixing_block | Offset | |
+| DIP | Microview | Sheets | Flat_hinge | Quadrant | |
+| D_connectors | Modules | Spades | Foot | Round | |
+| Displays | Nuts | Spools | Handle | Rounded_cylinder | |
+| Extrusion_brackets | O_ring | Springs | PCB_mount | Rounded_polygon | |
+| Extrusions | Opengrab | Stepper_motors | PSU_shroud | Sector | |
+| Fans | PCB | Swiss_clips | Printed_box | Sweep | |
+| Fuseholder | PCBs | Toggles | Ribbon_clamp | Thread | |
+| Geared_steppers | PSUs | Transformers | SSR_shroud | Tube | |
+| Green_terminals | Panel_meters | Tubings | Screw_knob | | |
+| Hot_ends | Pillars | Variacs | Socket_box | | |
+| Hygrometer | Pin_headers | Veroboard | Strap_handle | | |
| IECs | Pulleys | Washers | | | |
| Inserts | | Wire | | | |
| | Zipties | | | |
@@ -4539,6 +4539,60 @@ Door latch for 6mm acrylic door for 3D printer. See [door_hinge](#door_hinge).
| 1 | door_latch.stl |
+Top
+
+---
+
+## 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.
+
+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.
+
+
+[printed/drag_chain.scad](printed/drag_chain.scad) Implementation.
+
+[tests/drag_chain.scad](tests/drag_chain.scad) Code for this example.
+
+### Properties
+| Function | Description |
+|:--- |:--- |
+| ```drag_chain_bwall(type)``` | Bottom wall |
+| ```drag_chain_name(type)``` | The name to allow more than one in a project |
+| ```drag_chain_size(type)``` | The internal size and link length |
+| ```drag_chain_travel(type)``` | X travel |
+| ```drag_chain_twall(type)``` | Top wall |
+| ```drag_chain_wall(type)``` | Side wall thickness |
+
+### Functions
+| Function | Description |
+|:--- |:--- |
+| ```drag_chain(name, size, travel, wall = 1.6, bwall = 1.5, twall = 1.5)``` | 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 |
+
+### Modules
+| Module | Description |
+|:--- |:--- |
+| ```drag_chain_assembly(type, pos = 0)``` | Drag chain assembly |
+
+
+
+### Printed
+| Qty | Filename |
+| ---:|:--- |
+| 14 | x_drag_chain_link.stl |
+| 1 | x_drag_chain_link_end.stl |
+| 1 | x_drag_chain_link_start.stl |
+
+### Assemblies
+| Qty | Name |
+| ---:|:--- |
+| 1 | x_drag_chain_assembly |
+
+
Top
---
diff --git a/tests/drag_chain.scad b/tests/drag_chain.scad
index 883f609..79da5b5 100644
--- a/tests/drag_chain.scad
+++ b/tests/drag_chain.scad
@@ -48,5 +48,12 @@ module drag_chains()
if($preview)
drag_chains();
-else
+else {
drag_chain_link(drag_chain);
+
+ translate([-x * 2, 0])
+ drag_chain_link(drag_chain, start = true);
+
+ translate([x * 2, 0])
+ drag_chain_link(drag_chain, end = true);
+}
diff --git a/tests/png/drag_chain.png b/tests/png/drag_chain.png
new file mode 100644
index 0000000..006c8c0
Binary files /dev/null and b/tests/png/drag_chain.png differ