NopSCADlib/printed/strap_handle.scad

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OpenSCAD

//
// NopSCADlib Copyright Chris Palmer 2018
// 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/>.
//
//
//! Retracting strap handle. Print the strap with flexible filament. Shown with default dimensions but can
//! be fully customised by passing a list of properties.
//
include <../core.scad>
use <../vitamins/insert.scad>
strap = strap();
wall = 2;
clearance = 0.5;
step = 0.3;
overlap = 3;
panel_clearance = 0.25;
counterbore = 1;
function strap_width(type = strap) = type[0]; //! Width of strap
function strap_thickness(type = strap) = type[1]; //! Thickness of strap
function strap_screw(type = strap) = type[2]; //! Screw type
function strap_panel(type = strap) = type[3]; //! Panel thickness
function strap_extension(type = strap) = type[4]; //! How much length of the strap that can pull out
function strap(width = 18, thickness = 2, screw = M3_pan_screw, panel_thickness = 3, extension = 25) = //! Construct a property list for a strap
[ width, thickness, screw, panel_thickness, extension ];
function strap_insert(type) = screw_insert(strap_screw(type)); //! The insert type
function strap_key(type) = strap_panel(type) - panel_clearance;
function strap_height(type) = wall + max(insert_length(strap_insert(type)) - strap_key(type), strap_thickness(type) + clearance); //! Height of the ends
function strap_end_width(type = strap) = strap_width(type) + 2 * (wall + clearance); //! Width of the ends
function strap_boss_r(type) = wall + insert_hole_radius(strap_insert(type));
function strap_min_width(type) = (strap_width(type) - 2 * (strap_boss_r(type) + clearance)) / 2;
module strap_boss_shape(type)
hull() {
r = strap_boss_r(type);
circle4n(r);
translate([r / 2, 0])
rounded_square([r, 2 * r], r = 1);
}
module strap_screw_positions(length, type = strap) //! Place children at the screw positions
for(end = [-1, 1])
translate([end * (length / 2 - wall - 2 * clearance - strap_min_width(type) - strap_boss_r(type) - strap_extension(type) / 2), 0])
rotate(end * 90 + 90)
children();
module strap_holes(length, type = strap, h = 100) //! The panel cut outs
extrude_if(h)
strap_screw_positions(length, type)
offset(cnc_bit_r + 0.05)
offset(-step - cnc_bit_r)
strap_boss_shape(type);
module strap(length, type = strap) { //! Generate the STL for the rubber strap
stl("strap");
len = length - 2 * (wall + clearance);
w = strap_width(type);
linear_extrude(strap_thickness(type), convexity = 3)
difference() {
rounded_square([len, w], w / 2 - eps);
for(end = [-1, 1])
translate([end * (len / 2 - strap_min_width(type) - strap_boss_r(type) - clearance), 0])
rotate(end * 90 + 90)
hull() {
offset(clearance)
strap_boss_shape(type);
translate([strap_extension(type) / 2, 0])
offset(clearance)
strap_boss_shape(type);
}
}
}
module strap_end(type = strap) { //! Generate the STL for end piece
stl("strap_end");
z1 = strap_height(type) - strap_thickness(type) - clearance;
z2 = strap_height(type) + strap_key(type);
r1 = strap_boss_r(type) - 1;
module outer()
hull() {
translate([0, -strap_end_width(type) / 2])
square([strap_boss_r(type) + overlap, strap_end_width(type)]);
translate([-strap_extension(type) / 2, 0])
circle(d = strap_end_width(type));
}
module with_hole()
difference() {
children();
circle(r1);
}
union() {
linear_extrude(z1)
with_hole()
outer();
translate_z(z1)
linear_extrude(strap_height(type) - z1)
difference() {
outer();
hull() {
translate([0, -strap_width(type) / 2 - clearance])
square([strap_boss_r(type) + overlap, strap_width(type) + 2 * clearance]);
translate([-strap_extension(type) / 2, 0])
circle(d = strap_width(type) + 2 * clearance);
}
}
linear_extrude(strap_height(type) - layer_height)
with_hole()
strap_boss_shape(type);
linear_extrude(z2)
with_hole()
offset(cnc_bit_r)
offset(-step - cnc_bit_r)
strap_boss_shape(type);
render() difference() {
cylinder(r = r1 + eps, h = z2);
translate_z(z2)
insert_hole(strap_insert(type), counterbore);
}
}
}
//
//! * Place the insert into the hole and push home with a soldering iron with a tapered bit heated to 200&deg;C.
//
module strap_end_assembly(type = strap)
assembly("strap_end") {
stl_colour(pp1_colour)
strap_end(type);
translate_z(strap_height(type) + strap_key(type))
insert(strap_insert(type));
}
module strap_assembly(length, type = strap) { //! Assembly with screws in place
screw = strap_screw(type);
washer = screw_washer(screw);
penny = penny_washer(washer);
insert = strap_insert(type);
screw_length = screw_shorter_than(washer_thickness(washer) + washer_thickness(penny) + insert_length(insert) + panel_clearance + counterbore);
stl_colour(pp4_colour) strap(length, type);
strap_screw_positions(length, type)
translate_z(strap_height(type))
vflip() {
explode(-50) strap_end_assembly(type);
translate_z(strap_height(type) + strap_panel(type))
screw_and_washer(screw, screw_length, true, true);
}
}