Added ends

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) {
+module drag_chain_link(type, start = false, end = false) {
-    stl(str(drag_chain_name(type), "_drag_chain_link"));
+    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;
+    inner_x_normal = s.x - wall;
-    roof_x = 2 * r - twall;
+    inner_x = start ? 0 : s.x - inner_x_normal;
-    floor_x = 2 * r;
+    roof_x_normal = 2 * r - twall;
-    cam_r = inner_x - clearance - r;
+    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]) {
@@ -77,13 +80,18 @@ module drag_chain_link(type) {
                 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([s.x - clearance - eps, 0])
+                            translate([outer_end_x - eps, 0])
                                 square([eps, os.z]);
                         }
+                        if(!start)
                             translate([r, r])
                                 horihole(pin_r, r);
                     }
@@ -93,52 +101,61 @@ module drag_chain_link(type) {
                     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])
+                                        square([eps, os.z]);
 
                                 translate([inner_x, 0])
                                     square([eps, os.z]);
                             }
                         }
                         // Cutout for top wall
+                        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
+                                        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);
 
             // Cheek joint
             translate([inner_x, 0, side * (s.y / 2 + wall) - 0.5])
-                cube([s.x - clearance - inner_x, os.z, 1]);
+                cube([outer_end_x - inner_x, os.z, 1]);
         }
 
-    // Roof
+    // Roof, actually the floor when printed
-    translate([roof_x, -s.y / 2 - 0.5])
+    roof_end = end ? s.x + 2 * r : s.x + r - twall - clearance;
-        cube([s.x + r - roof_x - twall - clearance, s.y + 1, twall]);
+    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
+    // Base, actually the roof when printed
-    translate([floor_x, -s.y / 2 - 0.5, os.z - bwall])
+    floor_end = end ? s.x + 2 * r : s.x + r;
-        cube([s.x + r - floor_x, s.y + 1, bwall]);
+    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
+    points = [                                      // Calculate list of hinge points
-        translate([-z / 2, 0, -z / 2])
-            stl_colour(n % 2 ? pp1_colour : pp2_colour)
-                drag_chain_link(type);
-
-
-    points = [                                      // Calculate lits 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"))
+    module link(n)                                  // Position and colour link with origin at the hinge hole
-        for(i = [0 : len(points) - 2]) let(v = points[i+1] - points[i])
+        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);
+    }
 }

readme.md

@@ -28,20 +28,20 @@ See [usage](docs/usage.md) for requirements, installation instructions and a usa
 <tr><td> <a href = "#Bulldogs">Bulldogs</a> </td><td> <a href = "#Leadnuts">Leadnuts</a> </td><td> <a href = "#SK_brackets">SK_brackets</a> </td><td> <a href = "#Corner_block">Corner_block</a> </td><td> <a href = "#Gears">Gears</a> </td><td> <a href = "#Sphere">Sphere</a> </td></tr>
 <tr><td> <a href = "#Buttons">Buttons</a> </td><td> <a href = "#Light_strips">Light_strips</a> </td><td> <a href = "#SMDs">SMDs</a> </td><td> <a href = "#Door_hinge">Door_hinge</a> </td><td> <a href = "#Hanging_hole">Hanging_hole</a> </td><td> <a href = "#Teardrops">Teardrops</a> </td></tr>
 <tr><td> <a href = "#Cable_strips">Cable_strips</a> </td><td> <a href = "#Linear_bearings">Linear_bearings</a> </td><td> <a href = "#SSRs">SSRs</a> </td><td> <a href = "#Door_latch">Door_latch</a> </td><td> <a href = "#Horiholes">Horiholes</a> </td><td></td></tr>
-<tr><td> <a href = "#Cameras">Cameras</a> </td><td> <a href = "#Magnets">Magnets</a> </td><td> <a href = "#Screws">Screws</a> </td><td> <a href = "#Fan_guard">Fan_guard</a> </td><td> <a href = "#Layout">Layout</a> </td><td></td></tr>
+<tr><td> <a href = "#Cameras">Cameras</a> </td><td> <a href = "#Magnets">Magnets</a> </td><td> <a href = "#Screws">Screws</a> </td><td> <a href = "#Drag_chain">Drag_chain</a> </td><td> <a href = "#Layout">Layout</a> </td><td></td></tr>
-<tr><td> <a href = "#Circlips">Circlips</a> </td><td> <a href = "#Mains_sockets">Mains_sockets</a> </td><td> <a href = "#Sealing_strip">Sealing_strip</a> </td><td> <a href = "#Fixing_block">Fixing_block</a> </td><td> <a href = "#Maths">Maths</a> </td><td></td></tr>
+<tr><td> <a href = "#Circlips">Circlips</a> </td><td> <a href = "#Mains_sockets">Mains_sockets</a> </td><td> <a href = "#Sealing_strip">Sealing_strip</a> </td><td> <a href = "#Fan_guard">Fan_guard</a> </td><td> <a href = "#Maths">Maths</a> </td><td></td></tr>
-<tr><td> <a href = "#Components">Components</a> </td><td> <a href = "#Microswitches">Microswitches</a> </td><td> <a href = "#Shaft_couplings">Shaft_couplings</a> </td><td> <a href = "#Flat_hinge">Flat_hinge</a> </td><td> <a href = "#Offset">Offset</a> </td><td></td></tr>
+<tr><td> <a href = "#Components">Components</a> </td><td> <a href = "#Microswitches">Microswitches</a> </td><td> <a href = "#Shaft_couplings">Shaft_couplings</a> </td><td> <a href = "#Fixing_block">Fixing_block</a> </td><td> <a href = "#Offset">Offset</a> </td><td></td></tr>
-<tr><td> <a href = "#DIP">DIP</a> </td><td> <a href = "#Microview">Microview</a> </td><td> <a href = "#Sheets">Sheets</a> </td><td> <a href = "#Foot">Foot</a> </td><td> <a href = "#Quadrant">Quadrant</a> </td><td></td></tr>
+<tr><td> <a href = "#DIP">DIP</a> </td><td> <a href = "#Microview">Microview</a> </td><td> <a href = "#Sheets">Sheets</a> </td><td> <a href = "#Flat_hinge">Flat_hinge</a> </td><td> <a href = "#Quadrant">Quadrant</a> </td><td></td></tr>
-<tr><td> <a href = "#D_connectors">D_connectors</a> </td><td> <a href = "#Modules">Modules</a> </td><td> <a href = "#Spades">Spades</a> </td><td> <a href = "#Handle">Handle</a> </td><td> <a href = "#Round">Round</a> </td><td></td></tr>
+<tr><td> <a href = "#D_connectors">D_connectors</a> </td><td> <a href = "#Modules">Modules</a> </td><td> <a href = "#Spades">Spades</a> </td><td> <a href = "#Foot">Foot</a> </td><td> <a href = "#Round">Round</a> </td><td></td></tr>
-<tr><td> <a href = "#Displays">Displays</a> </td><td> <a href = "#Nuts">Nuts</a> </td><td> <a href = "#Spools">Spools</a> </td><td> <a href = "#PCB_mount">PCB_mount</a> </td><td> <a href = "#Rounded_cylinder">Rounded_cylinder</a> </td><td></td></tr>
+<tr><td> <a href = "#Displays">Displays</a> </td><td> <a href = "#Nuts">Nuts</a> </td><td> <a href = "#Spools">Spools</a> </td><td> <a href = "#Handle">Handle</a> </td><td> <a href = "#Rounded_cylinder">Rounded_cylinder</a> </td><td></td></tr>
-<tr><td> <a href = "#Extrusion_brackets">Extrusion_brackets</a> </td><td> <a href = "#O_ring">O_ring</a> </td><td> <a href = "#Springs">Springs</a> </td><td> <a href = "#PSU_shroud">PSU_shroud</a> </td><td> <a href = "#Rounded_polygon">Rounded_polygon</a> </td><td></td></tr>
+<tr><td> <a href = "#Extrusion_brackets">Extrusion_brackets</a> </td><td> <a href = "#O_ring">O_ring</a> </td><td> <a href = "#Springs">Springs</a> </td><td> <a href = "#PCB_mount">PCB_mount</a> </td><td> <a href = "#Rounded_polygon">Rounded_polygon</a> </td><td></td></tr>
-<tr><td> <a href = "#Extrusions">Extrusions</a> </td><td> <a href = "#Opengrab">Opengrab</a> </td><td> <a href = "#Stepper_motors">Stepper_motors</a> </td><td> <a href = "#Printed_box">Printed_box</a> </td><td> <a href = "#Sector">Sector</a> </td><td></td></tr>
+<tr><td> <a href = "#Extrusions">Extrusions</a> </td><td> <a href = "#Opengrab">Opengrab</a> </td><td> <a href = "#Stepper_motors">Stepper_motors</a> </td><td> <a href = "#PSU_shroud">PSU_shroud</a> </td><td> <a href = "#Sector">Sector</a> </td><td></td></tr>
-<tr><td> <a href = "#Fans">Fans</a> </td><td> <a href = "#PCB">PCB</a> </td><td> <a href = "#Swiss_clips">Swiss_clips</a> </td><td> <a href = "#Ribbon_clamp">Ribbon_clamp</a> </td><td> <a href = "#Sweep">Sweep</a> </td><td></td></tr>
+<tr><td> <a href = "#Fans">Fans</a> </td><td> <a href = "#PCB">PCB</a> </td><td> <a href = "#Swiss_clips">Swiss_clips</a> </td><td> <a href = "#Printed_box">Printed_box</a> </td><td> <a href = "#Sweep">Sweep</a> </td><td></td></tr>
-<tr><td> <a href = "#Fuseholder">Fuseholder</a> </td><td> <a href = "#PCBs">PCBs</a> </td><td> <a href = "#Toggles">Toggles</a> </td><td> <a href = "#SSR_shroud">SSR_shroud</a> </td><td> <a href = "#Thread">Thread</a> </td><td></td></tr>
+<tr><td> <a href = "#Fuseholder">Fuseholder</a> </td><td> <a href = "#PCBs">PCBs</a> </td><td> <a href = "#Toggles">Toggles</a> </td><td> <a href = "#Ribbon_clamp">Ribbon_clamp</a> </td><td> <a href = "#Thread">Thread</a> </td><td></td></tr>
-<tr><td> <a href = "#Geared_steppers">Geared_steppers</a> </td><td> <a href = "#PSUs">PSUs</a> </td><td> <a href = "#Transformers">Transformers</a> </td><td> <a href = "#Screw_knob">Screw_knob</a> </td><td> <a href = "#Tube">Tube</a> </td><td></td></tr>
+<tr><td> <a href = "#Geared_steppers">Geared_steppers</a> </td><td> <a href = "#PSUs">PSUs</a> </td><td> <a href = "#Transformers">Transformers</a> </td><td> <a href = "#SSR_shroud">SSR_shroud</a> </td><td> <a href = "#Tube">Tube</a> </td><td></td></tr>
-<tr><td> <a href = "#Green_terminals">Green_terminals</a> </td><td> <a href = "#Panel_meters">Panel_meters</a> </td><td> <a href = "#Tubings">Tubings</a> </td><td> <a href = "#Socket_box">Socket_box</a> </td><td></td><td></td></tr>
+<tr><td> <a href = "#Green_terminals">Green_terminals</a> </td><td> <a href = "#Panel_meters">Panel_meters</a> </td><td> <a href = "#Tubings">Tubings</a> </td><td> <a href = "#Screw_knob">Screw_knob</a> </td><td></td><td></td></tr>
-<tr><td> <a href = "#Hot_ends">Hot_ends</a> </td><td> <a href = "#Pillars">Pillars</a> </td><td> <a href = "#Variacs">Variacs</a> </td><td> <a href = "#Strap_handle">Strap_handle</a> </td><td></td><td></td></tr>
+<tr><td> <a href = "#Hot_ends">Hot_ends</a> </td><td> <a href = "#Pillars">Pillars</a> </td><td> <a href = "#Variacs">Variacs</a> </td><td> <a href = "#Socket_box">Socket_box</a> </td><td></td><td></td></tr>
-<tr><td> <a href = "#Hygrometer">Hygrometer</a> </td><td> <a href = "#Pin_headers">Pin_headers</a> </td><td> <a href = "#Veroboard">Veroboard</a> </td><td></td><td></td><td></td></tr>
+<tr><td> <a href = "#Hygrometer">Hygrometer</a> </td><td> <a href = "#Pin_headers">Pin_headers</a> </td><td> <a href = "#Veroboard">Veroboard</a> </td><td> <a href = "#Strap_handle">Strap_handle</a> </td><td></td><td></td></tr>
 <tr><td> <a href = "#IECs">IECs</a> </td><td> <a href = "#Pulleys">Pulleys</a> </td><td> <a href = "#Washers">Washers</a> </td><td></td><td></td><td></td></tr>
 <tr><td> <a href = "#Inserts">Inserts</a> </td><td></td><td> <a href = "#Wire">Wire</a> </td><td></td><td></td><td></td></tr>
 <tr><td></td><td></td><td> <a href = "#Zipties">Zipties</a> </td><td></td><td></td><td></td></tr>
@@ -4539,6 +4539,60 @@ Door latch for 6mm acrylic door for 3D printer. See [door_hinge](#door_hinge).
 |   1 | door_latch.stl |
 
 
+<a href="#top">Top</a>
+
+---
+<a name="Drag_chain"></a>
+## 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 |
+
+![drag_chain](tests/png/drag_chain.png)
+
+### 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 |
+
+
 <a href="#top">Top</a>
 
 ---

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);
+}