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Merge pull request #238 from adrianVmariano/master

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Rabbit clips
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Revar Desmera 2020-08-17 18:15:28 -07:00 committed by GitHub
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@ -564,6 +564,7 @@ module dovetail(gender, length, l, width, w, height, h, angle, slope, taper, bac
}
// Section: Tension Clips
// h is total height above 0 of the nub
// nub extends below xy plane by distance nub/2
@ -780,5 +781,244 @@ module snap_pin_socket(size, r, radius, l,length, d,diameter,nub_depth, snap, fi
// Module: rabbit_clip()
// Usage:
// rabbit_clip(type, length, width, snap, thickness, depth, [compression], [clearance], [lock],
// [lock_clearance], [splineteps], [anchor], [orient], [spin])
// Description:
// Creates a clip with two flexible ears to lock into a mating socket, or create a mask to produce the appropriate
// mating socket. The clip can be made to insert and release easily, or to hold much better, or it can be
// created with locking flanges that will make it very hard or impossible to remove. Unlike the snap pin, this clip
// is rectangular and can be made at any height, so a suitable clip could be very thin. It's also possible to get a
// solid connection with a short pin.
// .
// The type parameters specifies whether to make a clip, a socket mask, or a double clip. The length is the
// total nominal length of the clip. (The actual length will be very close, but not equal to this.) The width
// gives the nominal width of the clip, which is the actual width of the clip at its base. The snap parameter
// gives the depth of the clip sides, which controls how easy the clip is to insert and remove. The clip "ears" are
// made over-wide by the compression value. A nonzero compression helps make the clip secure in its socket.
// The socket's width and length are increased by the clearance value which creates some space and can compensate
// for printing inaccuracy. The socket will be slightly longer than the nominal width. The thickness is the thickness
// curved line that forms the clip. The clip depth is the amount the basic clip shape is extruded. Be sure that you
// make the socket with a larger depth than the clip (try 0.4 mm) to allow ease of insertion of the clip. The clearance
// value does not apply to the depth. The splinesteps parameter increases the sampling of the clip curves.
// .
// By default clips appear with orient=UP and sockets with orient=DOWN.
// .
// The first figure shows the dimensions of the rabbit clip. The second figure shows the clip in red overlayed on
// its socket in yellow. The left clip has a nonzero clearance, so its socket is bigger than the clip all around.
// The right hand locking clip has no clearance, but it has a lock clearance, which provides some space behind
// the lock to allow the clip to fit. (Note that depending on your printer, this can be set to zero.)
//
// Figure(2DMed):
// snap=1.5;
// comp=0.75;
// mid = 8.053; // computed in rabbit_clip
// tip = [-4.58,18.03];
// translate([9,3]){
// back_half()
// rabbit_clip("pin",width=12, length=18, depth=1, thickness = 1, compression=comp, snap=snap, orient=BACK);
// color("blue"){
// stroke([[6,0],[6,18]],width=0.1);
// stroke([[6+comp, 12], [6+comp, 18]], width=.1);
// }
// color("red"){
// stroke([[6-snap,mid], [6,mid]], endcaps="arrow2",width=0.15);
// translate([6+.4,mid-.15])text("snap",size=1,valign="center");
// translate([6+comp/2,19.5])text("compression", size=1, halign="center");
// stroke([[6+comp/2,19.3], [6+comp/2,17.7]], endcap2="arrow2", width=.15);
// fwd(1.1)text("width",size=1,halign="center");
// xflip_copy()stroke([[2,-.7], [6,-.7]], endcap2="arrow2", width=.15);
// move([-6.7,mid])rot(90)text("length", size=1, halign="center");
// stroke([[-7,10.3], [-7,18]], width=.15, endcap2="arrow2");
// stroke([[-7,0], [-7,5.8]], width=.15,endcap1="arrow2");
// stroke([tip, tip-[0,1]], width=.15);
// move([tip.x+2,19.5])text("thickness", halign="center",size=1);
// stroke([[tip.x+2, 19.3], tip+[.1,.1]], width=.15, endcap2="arrow2");
// }
// }
//
// Figure(2DMed):
// snap=1.5;
// comp=0;
// translate([29,3]){
// back_half()
// rabbit_clip("socket", width=12, length=18, depth=1, thickness = 1, compression=comp, snap=snap, orient=BACK,lock=true);
// color("red")back_half()
// rabbit_clip("pin",width=12, length=18, depth=1, thickness = 1, compression=comp, snap=snap,
// orient=BACK,lock=true,lock_clearance=1);
// }
// translate([9,3]){
// back_half()
// rabbit_clip("socket", clearance=.5,width=12, length=18, depth=1, thickness = 1,
// compression=comp, snap=snap, orient=BACK,lock=false);
// color("red")back_half()
// rabbit_clip("pin",width=12, length=18, depth=1, thickness = 1, compression=comp, snap=snap,
// orient=BACK,lock=false,lock_clearance=1);
// }
// Arguments:
// type = One of "pin", "socket", "male", "female" or "double" to specify what to make.
// length = nominal clip length
// width = nominal clip width
// snap = depth of hollow on the side of the clip
// thickness = thickness of the clip "line"
// depth = amount to extrude clip (give extra room for the socket, about 0.4mm)
// compression = excess width at the "ears" to lock more tightly. Default: 0.1
// clearance = extra space in the socket for easier insertion. Default: 0.1
// lock = set to true to make a locking clip that may be irreversible. Default: false
// lock_clearance = give clearance for the lock. Default: 0
// splinesteps = number of samples in the curves of the clip. Default: 8
// anchor = anchor point for clip
// orient = clip orientation. Default: UP for pins, DOWN for sockets
// spin = spin the clip. Default: 0
//
// Example: Here are several sizes that work printed in PLA on a Prusa MK3, with default clearance of 0.1 and a depth of 5
// module test_pair(length, width, snap, thickness, compression, lock=false)
// {
// depth = 5;
// extra_depth = 10;// Change this to 0.4 for closed sockets
// cuboid([max(width+5,12),12, depth], chamfer=.5, edges=[FRONT,"Y"], anchor=BOTTOM)
// attach(BACK)
// rabbit_clip(type="pin",length=length, width=width,snap=snap,thickness=thickness,depth=depth,
// compression=compression,lock=lock);
// right(width+13)
// diff("remove")
// cuboid([width+8,max(12,length+2),depth+3], chamfer=.5, edges=[FRONT,"Y"], anchor=BOTTOM)
// attach(BACK)
// rabbit_clip(type="socket",length=length, width=width,snap=snap,thickness=thickness,depth=depth+extra_depth,
// lock=lock,compression=0,$tags="remove");
// }
// left(37)ydistribute(spacing=28){
// test_pair(length=6, width=7, snap=0.25, thickness=0.8, compression=0.1);
// test_pair(length=3.5, width=7, snap=0.1, thickness=0.8, compression=0.1); // snap = 0.2 gives a firmer connection
// test_pair(length=3.5, width=5, snap=0.1, thickness=0.8, compression=0.1); // hard to take apart
// }
// right(17)ydistribute(spacing=28){
// test_pair(length=12, width=10, snap=1, thickness=1.2, compression=0.2);
// test_pair(length=8, width=7, snap=0.75, thickness=0.8, compression=0.2, lock=true); // With lock, very firm and irreversible
// test_pair(length=8, width=7, snap=0.75, thickness=0.8, compression=0.2, lock=true); // With lock, very firm and irreversible
// }
// Example: Double clip to connect two sockets
// rabbit_clip("double",length=8, width=7, snap=0.75, thickness=0.8, compression=0.2,depth=5);
// Example: A modified version of the clip that acts like a backpack strap clip, where it locks tightly but you can squeeze to release.
// cuboid([25,15,5],anchor=BOTTOM)
// attach(BACK)rabbit_clip("pin", length=25, width=25, thickness=1.5, snap=2, compression=0, lock=true, depth=5, lock_clearance=3);
// left(32)
// diff("remove")
// cuboid([30,30,11],orient=BACK,anchor=BACK){
// attach(BACK)rabbit_clip("socket", length=25, width=25, thickness=1.5, snap=2, compression=0, lock=true, depth=5.5, lock_clearance=3,$tags="remove");
// xflip_copy()
// position(FRONT+LEFT)
// xscale(0.8)
// zcyl(l=20,r=13.5, $tags="remove",$fn=64);
// }
module rabbit_clip(type, length, width, snap, thickness, depth, compression=0.1, clearance=.1, lock=false, lock_clearance=0,
splinesteps=8, anchor, orient, spin=0)
{
assert(is_num(width) && width>0,"Width must be a positive value");
assert(is_num(length) && length>0, "Length must be a positive value");
assert(is_num(thickness) && thickness>0, "Thickness must be a positive value");
assert(is_num(snap) && snap>=0, "Snap must be a non-negative value");
assert(is_num(depth) && depth>0, "Depth must be a positive value");
assert(is_num(compression) && compression >= 0, "Compression must be a nonnegative value");
assert(is_bool(lock));
assert(is_num(lock_clearance));
legal_types = ["pin","socket","male","female","double"];
assert(in_list(type,legal_types),str("type must be one of ",legal_types));
if (type=="double") {
attachable(size=[width+2*compression, depth, 2*length], anchor=default(anchor,BACK), spin=spin, orient=default(orient,BACK)){
union(){
rabbit_clip("pin", length=length, width=width, snap=snap, thickness=thickness, depth=depth, compression=compression,
lock=lock, anchor=BOTTOM, orient=UP);
rabbit_clip("pin", length=length, width=width, snap=snap, thickness=thickness, depth=depth, compression=compression,
lock=lock, anchor=BOTTOM, orient=DOWN);
cuboid([width-thickness, depth, thickness]);
}
children();
}
} else {
anchor = default(anchor,BOTTOM);
is_pin = in_list(type,["pin","male"]);
default_overlap = 0.01 * (is_pin?1:-1); // Shift by this much to undo default overlap
extra = 0.02; // Amount of extension below nominal based position for the socket, must exceed default overlap of 0.01
clearance = is_pin ? 0 : clearance;
compression = is_pin ? compression : 0;
orient = is_def(orient) ? orient
: is_pin ? UP
: DOWN;
earwidth = 2*thickness+snap;
point_length = earwidth/2.15;
// The adjustment is using cos(theta)*earwidth/2 and sin(theta)*point_length, but the computation
// is obscured because theta is atan(length/2/snap)
scaled_len = length - 0.5 * (earwidth * snap + point_length * length) / sqrt(sqr(snap)+sqr(length/2));
bottom_pt = [0,max(scaled_len*0.15+thickness, 2*thickness)];
ctr = [width/2,scaled_len] + line_normal([width/2-snap, scaled_len/2], [width/2, scaled_len]) * earwidth/2;
inside_pt = circle_circle_tangents(bottom_pt, 0, ctr, earwidth/2)[0][1];
sidepath =[
[width/2,0],
[width/2-snap,scaled_len/2],
[width/2+(is_pin?compression:0), scaled_len],
ctr - point_length * line_normal([width/2,scaled_len], inside_pt),
inside_pt
];
fullpath = concat(
sidepath,
[bottom_pt],
reverse(apply(xflip(),sidepath))
);
assert(fullpath[4].y < fullpath[3].y, "Pin is too wide for its length");
snapmargin = -snap + select(sidepath,-1).x;// - compression;
if (is_pin){
if (snapmargin<0) echo("WARNING: The snap is too large for the clip to squeeze to fit its socket")
echo(snapmargin=snapmargin);
}
// Force tangent to be vertical at the outer edge of the clip to avoid overshoot
fulltangent = list_set(path_tangents(fullpath, uniform=false),[2,8], [[0,1],[0,-1]]);
subset = is_pin ? [0:10] : [0,1,2,3, 7,8,9,10]; // Remove internal points from the socket
tangent = select(fulltangent, subset);
path = select(fullpath, subset);
socket_smooth = .04;
pin_smooth = [.075, .075, .15, .12, .06];
smoothing = is_pin
? concat(pin_smooth, reverse(pin_smooth))
: let(side_smooth=select(pin_smooth, 0, 2))
concat(side_smooth, [socket_smooth], reverse(side_smooth));
bez = path_to_bezier(path,relsize=smoothing,tangents=tangent);
rounded = bezier_polyline(bez,splinesteps=splinesteps);
bounds = pointlist_bounds(rounded);
kk = search([bounds[1].y], subindex(rounded,1));
echo(rounded[kk[0]]);
extrapt = is_pin ? [] : [rounded[0] - [0,extra]];
finalpath = is_pin ? rounded
: let(withclearance=offset(rounded, r=-clearance))
concat( [[withclearance[0].x,-extra]],
withclearance,
[[-withclearance[0].x,-extra]]);
attachable(size=[bounds[1].x-bounds[0].x, depth, bounds[1].y-bounds[0].y], anchor=anchor, spin=spin, orient=orient){
xrot(90)
translate([0,-(bounds[1].y-bounds[0].y)/2+default_overlap,-depth/2])
linear_extrude(height=depth, convexity=10) {
if (lock)
xflip_copy()
right(clearance)
polygon([sidepath[1]+[-thickness/10,lock_clearance],
sidepath[2],
[sidepath[2].x,sidepath[1].y+lock_clearance]]);
if (is_pin)
offset_stroke(finalpath, width=[thickness,0]);
else
polygon(finalpath);
}
children();
}
}
}
// vim: expandtab tabstop=4 shiftwidth=4 softtabstop=4 nowrap