Type in drag chain blurb, fixes #100

Added blower_exit_offset().
Fixed corner shape and exit dimensions.
Updated images and readme.

libtest.scad

@@ -52,6 +52,7 @@ use <tests/circlips.scad>
 use <tests/components.scad>
 use <tests/d_connectors.scad>
 use <tests/displays.scad>
+use <tests/drag_chain.scad>
 use <tests/extrusions.scad>
 use <tests/extrusion_brackets.scad>
 use <tests/fans.scad>
@@ -417,8 +418,12 @@ translate([x4 + 200, belts_y + 58]) {
 
     translate([0, 60])
         opengrab_test();
+
 }
 
+translate([x4 + 175, belts_y, -20])
+    drag_chains();
+
 translate([x4, rails_y + 130])
     rails();
 

printed/drag_chain.scad

@@ -0,0 +1,285 @@
+//
+// NopSCADlib Copyright Chris Palmer 2020
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+//
+
+//
+//! Parametric cable drag chain to limit the bend radius of a cable run.
+//!
+//! Each link has a maximum bend angle of 45&deg;, so the mininium radius is proportional to the link length.
+//!
+//! The travel property 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.
+//
+
+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_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))
+        s.x / 2 / sin(360 / 16);
+
+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, 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;
+
+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 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);
+    wall = drag_chain_wall(type);
+    bwall = drag_chain_bwall(type);
+    twall = drag_chain_twall(type);
+    os = drag_chain_outer_size(type);
+    r = os.z / 2;
+    pin_r = r / 2;
+
+    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_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");
+
+    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([outer_end_x - eps, 0])
+                                        square([eps, os.z]);
+                                }
+                                if(!start)
+                                    translate([socket_x, 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([pin_x, r])
+                                                rotate(180)
+                                                    teardrop(r = r, h = 0);
+
+                                            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([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]);
+                }
+
+            // 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);
+
+    }
+
+    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])
+                cube([w, wall, twall], center = true);
+
+            h = round_to_layer(r - pin_r / sqrt(2));
+            y = s.y / 2  + max(wall + w / 2 + clearance, 2 * wall + clearance - w / 2);
+            translate([s.x + r, side * y, h / 2])
+                cube([pin_r * sqrt(2), w, h], center = true);
+
+            gap = cam_x - pin_r / sqrt(2) + extrusion_width;
+            translate([s.x + r + cam_x - gap / 2, side * (s.y / 2 + wall + clearance / 2), layer_height / 2])
+                cube([gap, 2 * wall + clearance, layer_height], center = true);
+        }
+    }
+}
+
+//! 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);
+    travel = drag_chain_travel(type);
+    links = ceil(travel / s.x);
+    actual_travel = links * s.x;
+    z = drag_chain_outer_size(type).z;
+
+    zb = z / 2;                                     // z of bottom track
+    c = [actual_travel / 2 + pos / 2, 0, r + zb];   // centre of bend
+
+    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,
+            p = max(p.x + dx, p.x) <= c.x ? p + [dx, 0, 0]      // Straight sections
+                  : let(q = circle_intersect(p, s.x, c, r))
+                        q.x <= c.x ? [p.x - sqrt(sqr(s.x) - sqr(p.z - zb)), 0, zb] // Transition back to straight
+                                   : q) // Circular section
+        p
+    ];
+    npoints = len(points);
+
+    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);
+    }
+}

printed/ribbon_clamp.scad

@@ -117,9 +117,13 @@ module ribbon_clamp_fastened_assembly(ways, thickness, screw = screw) { //! Clam
 
 module ribbon_clamp_20_stl() ribbon_clamp(20);
 module ribbon_clamp_8_2_stl() ribbon_clamp(8, M2_dome_screw);
+module ribbon_clamp_7_2_stl() ribbon_clamp(8, M2_dome_screw);
 
 //! * Place inserts into the holes and press home with a soldering iron with a conical bit heated to 200°C.
 module ribbon_clamp_20_assembly() ribbon_clamp_assembly(20);
 
 //! * Place inserts into the holes and press home with a soldering iron with a conical bit heated to 200°C.
 module ribbon_clamp_8_2_assembly() ribbon_clamp_assembly(8, M2_dome_screw);
+
+//! * Place inserts into the holes and press home with a soldering iron with a conical bit heated to 200°C.
+module ribbon_clamp_7_2_assembly() ribbon_clamp_assembly(8, M2_dome_screw);

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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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 = "#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> <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>
@@ -296,11 +296,18 @@ Models of radial blowers.
 | ```blower_wall(type)``` | Side wall thickness |
 | ```blower_width(type)``` | Width of enclosing rectangle |
 
+### Functions
+| Function | Description |
+|:--- |:--- |
+| ```blower_casing_is_square(type)``` | True for square radial fans, false for spiral shape radial blowers |
+| ```blower_exit_offset(type)``` | Offset of exit's centre from the edge |
+
 ### Modules
 | Module | Description |
 |:--- |:--- |
 | ```blower(type)``` | Draw specified blower |
 | ```blower_hole_positions(type)``` | Translate children to screw hole positions |
+| ```blower_square(type)``` | Draw a square blower |
 
 ![blowers](tests/png/blowers.png)
 
@@ -309,8 +316,11 @@ Models of radial blowers.
 | ---:|:--- |:---|
 |   1 | ```blower(PE4020)``` |  Blower Pengda Technology 4020 |
 |   1 | ```blower(RB5015)``` |  Blower Runda RB5015 |
+|   4 | ```screw(M2_cap_screw, 8)``` |  Screw M2 cap x  8mm |
 |   3 | ```screw(M3_cap_screw, 20)``` |  Screw M3 cap x 20mm |
 |   2 | ```screw(M4_cap_screw, 25)``` |  Screw M4 cap x 25mm |
+|   1 | ```blower(BL40x10)``` |  Square radial 4010 |
+|   4 | ```washer(M2_washer)``` |  Washer  M2 x 5mm x 0.3mm |
 |   3 | ```washer(M3_washer)``` |  Washer  M3 x 7mm x 0.5mm |
 |   2 | ```washer(M4_washer)``` |  Washer  M4 x 9mm x 0.8mm |
 
@@ -4539,6 +4549,66 @@ 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 of 45&deg;, so the mininium radius is proportional to the link length.
+
+The travel property 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_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 |
+| ```drag_chain_wall(type)``` | Side wall thickness |
+
+### Functions
+| Function | Description |
+|:--- |:--- |
+| ```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)
+
+### 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>
 
 ---

scripts/plateup.py

@@ -87,24 +87,25 @@ def plateup(target, part_type, usage = None):
                     match = re.match(r'^ECHO: "~(.*?\.' + part_type + r').*"$', line)
                     if match:
                         used.append(match.group(1))
-    #
-    # Copy file that are not included
-    #
     copied = []
-    for file in os.listdir(parts_dir):
-        if file.endswith('.' + part_type) and not file in used:
-            src = parts_dir + '/' + file
-            dst = target_dir + '/' + file
-            if mtime(src) > mtime(dst):
-                print("Copying %s to %s" % (src, dst))
-                copyfile(src, dst)
-            copied.append(file)
-    #
-    # Remove any cruft
-    #
-    targets = [file[:-4] + part_type for file in all_sources]
-    for file in os.listdir(target_dir):
-        if file.endswith('.' + part_type):
-            if not file in targets and not file in copied:
-                print("Removing %s" % file)
-                os.remove(target_dir + '/' + file)
+    if all_sources:
+        #
+        # Copy files that are not included
+        #
+        for file in os.listdir(parts_dir):
+            if file.endswith('.' + part_type) and not file in used:
+                src = parts_dir + '/' + file
+                dst = target_dir + '/' + file
+                if mtime(src) > mtime(dst):
+                    print("Copying %s to %s" % (src, dst))
+                    copyfile(src, dst)
+                copied.append(file)
+        #
+        # Remove any cruft
+        #
+        targets = [file[:-4] + part_type for file in all_sources]
+        for file in os.listdir(target_dir):
+            if file.endswith('.' + part_type):
+                if not file in targets and not file in copied:
+                    print("Removing %s" % file)
+                    os.remove(target_dir + '/' + file)

tests/drag_chain.scad

@@ -0,0 +1,59 @@
+//
+// NopSCADlib Copyright Chris Palmer 2020
+// nop.head@gmail.com
+// hydraraptor.blogspot.com
+//
+// This file is part of NopSCADlib.
+//
+// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+//
+// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with NopSCADlib.
+// If not, see <https://www.gnu.org/licenses/>.
+//
+
+// Link length between hinges
+x = 10; //[8 : 30]
+
+// Link inner width
+y = 10; //[5 : 30]
+
+// Link inner height
+z = 5;  //[4 : 11]
+// Side wall thickness
+wall = 1.6; //[0.9: 0.1: 3]
+// Bottom wall thickness
+bwall = 1.5; //[1: 0.25: 3]
+// Top wall thickness
+twall = 1.5; //[1: 0.25: 3]
+// Max travel in each direction
+travel = 100;
+// Current position
+pos = 50; // [-100 : 1 : 100]
+
+include <../core.scad>
+use <../printed/drag_chain.scad>
+
+include <../vitamins/leadnuts.scad>
+
+drag_chain = drag_chain("x", [x, y, z], travel, wall = wall, bwall = bwall, twall = twall);
+
+module drag_chains()
+    drag_chain_assembly(drag_chain, pos);
+
+if($preview)
+    drag_chains();
+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);
+}

vitamins/belt.scad

@@ -54,7 +54,7 @@ module belt(type, points, gap = 0, gap_pos = undef, belt_colour = grey(20), toot
 
     tangents = rounded_polygon_tangents(points);
 
-    length = ceil((rounded_polygon_length(points, tangents) - gap) / pitch) * pitch;
+    length = ceil((rounded_polygon_length(points, tangents) - (is_list(gap) ? gap.x + gap.y : gap)) / pitch) * pitch;
 
     module shape() rounded_polygon(points, tangents);
 
@@ -65,7 +65,7 @@ module belt(type, points, gap = 0, gap_pos = undef, belt_colour = grey(20), toot
             translate([gap_pos.x, gap_pos.y])
                 rotate(is_undef(gap_pos.z) ? 0 : gap_pos.z)
                     translate([0, ph - thickness / 2])
-                        square([gap, thickness + eps], center = true);
+                        square(is_list(gap) ? [gap.x, gap.y + thickness + eps] : [gap, thickness + eps], center = true);
 
     color(belt_colour)
         linear_extrude(width, center = true)

vitamins/blower.scad

@@ -22,6 +22,8 @@
 //
 include <../utils/core/core.scad>
 use <../utils/rounded_cylinder.scad>
+use <../utils/quadrant.scad>
+use <screw.scad>
 
 function blower_length(type)      = type[2]; //! Length of enclosing rectangle
 function blower_width(type)       = type[3]; //! Width of enclosing rectangle
@@ -39,8 +41,87 @@ function blower_top(type)         = type[14]; //! Thickness of the top
 function blower_wall(type)        = type[15]; //! Side wall thickness
 function blower_lug(type)         = type[16]; //! Height of the lugs
 
+function blower_casing_is_square(type) = len(blower_screw_holes(type)) > 3; //! True for square radial fans, false for spiral shape radial blowers
+function blower_exit_offset(type) = blower_casing_is_square(type) ? blower_length(type) / 2 : blower_exit(type) / 2; //! Offset of exit's centre from the edge
+
 fan_colour = grey(20);
 
+module blower_fan(type, casing_is_square) {
+    module squarish(s, n) {
+        polygon([
+            for(i = [0 : n]) [i * s.x / n,  s.y + (i % 2) * eps],
+            for(i = [0 : n]) [s.x - i * s.x / n, (i % 2) * eps],
+        ]);
+    }
+
+    depth = blower_depth(type);
+    blade_ir = blower_hub(type) / 2 + 0.5; // slight gap between main part of blades and hub
+    blade_len = casing_is_square
+        ? (blower_bore(type) - 1) / 2 - blade_ir // fan constrained by bore hole
+        : blower_width(type) - blower_axis(type).x- blower_wall(type) - blade_ir; // fan extends to casing
+    blade_thickness = 0.75;
+    blade_count = 25;
+
+    base_offset = 1;
+    translate([blower_axis(type).x, blower_axis(type).y, blower_base(type) + base_offset])
+        linear_extrude(blower_hub_height(type) - 0.5 - blower_base(type) - base_offset, center = false, convexity = 4, twist = -30, slices = round(depth / 2))
+            for(i = [0 : blade_count - 1])
+                rotate((360 * i) / blade_count)
+                    translate([blade_ir, -blade_thickness / 2])
+                        squarish([blade_len, blade_thickness], round(blade_len / 2));
+}
+
+module blower_square(type) { //! Draw a square blower
+    width = blower_width(type);
+    depth = blower_depth(type);
+    wall = blower_wall(type);
+    hole_pitch = (blower_screw_holes(type)[1].x - blower_screw_holes(type)[0].x) / 2;
+    corner_radius = width / 2 - hole_pitch;
+    corner_inset = (width - blower_exit(type)) / 2;
+
+    module square_inset_corners(remove_center = false)
+        difference() {
+            //overall outside
+                square([width, width], center = false);
+
+            if (remove_center) {
+                // cut out the inside, leaving the corners
+                translate([corner_inset + wall, -eps])
+                    square([width - 2 * (wall + corner_inset), width - wall + eps], center = false);
+
+                translate([wall, corner_inset + wall])
+                    square([width - 2 * wall, width - 2 * (wall + corner_inset)], center = false);
+            } else {
+                // cut out the bore for the fan
+                translate(blower_axis(type))
+                    circle(d = blower_bore(type));
+            }
+            // corner inset
+            translate([width / 2, width / 2])
+            for(i = [0 : 3])
+                rotate(i * 90)
+                    translate([-width / 2 - eps, -width/ 2 - eps])
+                        quadrant(corner_inset, corner_inset - corner_radius);
+        }
+
+    base_height = blower_base(type);
+    linear_extrude(base_height)
+        difference () {
+            rounded_square([width, width], corner_radius, center = false);
+
+            blower_hole_positions(type)
+                circle(d = blower_screw_hole(type));
+        }
+
+    translate_z(base_height)
+        linear_extrude(depth - base_height)
+            square_inset_corners(remove_center = true);
+
+    translate_z(depth - base_height)
+        linear_extrude(blower_top(type))
+            square_inset_corners();
+}
+
 module blower(type) { //! Draw specified blower
     length = blower_length(type);
     width = blower_width(type);
@@ -70,55 +151,63 @@ module blower(type) { //! Draw specified blower
 
     vitamin(str("blower(", type[0], "): ", type[1]));
 
+    is_square = blower_casing_is_square(type); // Description starts with square!
     color(fan_colour) {
-        // screw lugs
-        linear_extrude(blower_lug(type), center = false)
-            for(hole = blower_screw_holes(type))
-                difference() {
-                    hull() {
+        if (is_square) {
+            blower_square(type);
+        } else {
+            // screw lugs
+            linear_extrude(blower_lug(type), center = false)
+                for(hole = blower_screw_holes(type))
+                    difference() {
+                        hull() {
+                            translate(hole)
+                                circle(d = blower_screw_hole(type) + 2 * blower_wall(type));
+
+                            translate(blower_axis(type))
+                                circle(d = blower_screw_hole(type) + 2 * blower_wall(type) + 7);
+                        }
                         translate(hole)
-                            circle(d = blower_screw_hole(type) + 2 * blower_wall(type));
+                            circle(d = blower_screw_hole(type));
 
-                        translate(blower_axis(type))
-                            circle(d = blower_screw_hole(type) + 2 * blower_wall(type) + 7);
-                    }
-                    translate(hole)
-                        circle(d = blower_screw_hole(type));
+                        shape(true);
+                }
 
-                    shape(true);
-               }
-        // rotor
-        translate(concat(blower_axis(type), [blower_base(type) + 1]))
-            rounded_cylinder(r = blower_hub(type) / 2, h = blower_hub_height(type) - blower_base(type) - 1, r2 = 1);
+            *%square([length, width]);
 
-        *%square([length, width]);
-
-        // base
-        linear_extrude(blower_base(type))
-            difference() {
-                shape();
-
-                translate(concat(blower_axis(type), [blower_base(type)]))
-                    circle(d = 2);
-           }
-        // sides
-        linear_extrude(depth)
-            difference() {
-                shape();
-
-                offset(-blower_wall(type))
-                    shape(true);
-           }
-
-        // top
-        translate_z(depth -blower_top(type))
-            linear_extrude(blower_top(type))
+            // base
+            linear_extrude(blower_base(type))
                 difference() {
                     shape();
 
                     translate(concat(blower_axis(type), [blower_base(type)]))
-                        circle(d = blower_bore(type));
-               }
+                        circle(d = 2);
+            }
+
+            // sides
+            linear_extrude(depth)
+                difference() {
+                    shape();
+
+                    offset(-blower_wall(type))
+                        shape(true);
+            }
+
+            // top
+            translate_z(depth -blower_top(type))
+                linear_extrude(blower_top(type))
+                    difference() {
+                        shape();
+
+                        translate(concat(blower_axis(type), [blower_base(type)]))
+                            circle(d = blower_bore(type));
+                }
+        }
+        // rotor
+        translate(concat(blower_axis(type), [blower_base(type) + 1]))
+            rounded_cylinder(r = blower_hub(type) / 2, h = blower_hub_height(type) - blower_base(type) - 1, r2 = 1);
+
+        blower_fan(type, is_square);
     }
 }
 

vitamins/blowers.scad

@@ -16,10 +16,16 @@
 // You should have received a copy of the GNU General Public License along with NopSCADlib.
 // If not, see <https://www.gnu.org/licenses/>.
 //
+//                                                   l     w   d   b     s              h   a            s    s                               e    h    b    t    w    l
+//                                                   e     i   e   o     c              u   x            c    c                               x    u    a    o    a    u
+//                                                   n     d   p   r     r              b   i            r    r                               i    b    s    p    l    g
+//                                                   g     t   t   e     e                  s            e    e                               t         e         l
+//                                                   t     h   h         w              d                w    w                                              t
+//                                                   h                                                  h    s                                         t         t
+RB5015 = ["RB5015", "Blower Runda RB5015",           51.3, 51, 15, 31.5, M4_cap_screw, 26, [27.3, 25.4], 4.5, [[4.3, 45.4], [47.3,7.4]],     20,   14,  1.5, 1.3, 1.2, 15];
+PE4020 = ["PE4020", "Blower Pengda Technology 4020", 40,   40, 20, 27.5, M3_cap_screw, 22, [21.5, 20  ], 3.2, [[37,3],[3,37],[37,37]],       29.3, 17,  1.7, 1.2, 1.3, 13];
+BL40x10 =["BL40x10","Square radial 4010",            40,   40,9.5, 27,   M2_cap_screw, 16, [24,   20  ], 2.4, [[2,2],[38,2],[2,38],[38,38]], 30  , 9.5, 1.5, 1.5, 1.1, 1.5];
 
-RB5015 = ["RB5015", "Blower Runda RB5015",           51.3, 51, 15, 31.5, M4_cap_screw, 26, [27.3, 25.4], 4.5, [[4.3, 45.4], [47.3,7.4]], 20, 14, 1.5, 1.3, 1.2, 15];
-PE4020 = ["PE4020", "Blower Pengda Technology 4020", 40,   40, 20, 27.5, M3_cap_screw, 22, [21.5, 20  ], 3.2, [[37,3],[3,37],[37,37]], 29.3, 17, 1.7, 1.2, 1.3, 13];
-
-blowers = [PE4020, RB5015];
+blowers = [BL40x10, PE4020, RB5015];
 
 use <blower.scad>