Machine Shop, Software

Dripworks Mainline Pipe Clamp

This is laid in against a need I hope never occurs:

Dripworks 0.75 inch pipe clamp
Dripworks 0.75 inch pipe clamp

It’s intended to clamp around one of the Dripworks mainline pipes carrying water from the pressure regulator to the driplines in the raised beds, should an errant shovel or fork find the pipe.

It descends from a long line of soaker hose clamps, with a 25 mm ID allowing for a silicone tape wrap as a water barrier.

The solid model has no surprises:

Dripworks Mainline Clamp - build view
Dripworks Mainline Clamp – build view

The OpenSCAD source code as a GitHub Gist:

// Dripworks 3/4 inch mainline clamp
// Ed Nisley KE4ZNU 2021-06
Layout = "Build"; // [Hose,Block,Show,Build]
HoseOD = 25.0;
TestFit = false; // true to build test fit slice from center
//- Extrusion parameters must match reality!
/* [Hidden] */
ThreadThick = 0.25;
ThreadWidth = 0.40;
HoleWindage = 0.2;
Protrusion = 0.1; // make holes end cleanly
inch = 25.4;
function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);
ID = 0;
OD = 1;
LENGTH = 2;
//----------
// Dimensions
// Hose lies along X axis
Hose = [200,HoseOD,HoseOD]; // X = longer than anything else
NumScrews = 2; // screws along each side of cable
WallThick = 3.0; // Thinnest printed wall
PlateThick = 1.5; // Stiffening plate thickness
// 8-32 stainless screws
Screw = [4.1,8.0,50.0]; // OD = head LENGTH = thread length
Washer = [4.4,9.5,1.0];
Nut = [4.1,9.7,3.3];
Block = [30.0,Hose.y + 2*Washer[OD],HoseOD + 2*WallThick]; // overall splice block size
echo(str("Block: ",Block));
ScrewMinLength = Block.z + 2*PlateThick + 2*Washer.z + Nut.z; // minimum screw length
echo(str("Screw min length: ",ScrewMinLength));
Kerf = 1.0; // cut through middle to apply compression
CornerRadius = Washer[OD]/2;
ScrewOC = [(Block.x - 2*CornerRadius) / (NumScrews - 1),
Block.y - 2*CornerRadius,
2*Block.z // ensure complete holes
];
echo(str("Screw OC: x=",ScrewOC.x," y=",ScrewOC.y));
//----------------------
// Useful routines
module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes
Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);
FixDia = Dia / cos(180/Sides);
cylinder(d=(FixDia + HoleWindage),h=Height,$fn=Sides);
}
// Hose shape
// This includes magic numbers measured from reality
module HoseProfile() {
NumSides = 12*4;
rotate([0,-90,0])
translate([0,0,-Hose.x/2])
resize([Hose.z,Hose.y,0])
cylinder(d=Hose.z,h=Hose.x,$fn=NumSides);
}
// Outside shape of splice Block
// Z centered on hose rim circles, not overall thickness through center ridge
module SpliceBlock() {
difference() {
hull()
for (i=[-1,1], j=[-1,1]) // rounded block
translate([i*(Block.x/2 - CornerRadius),j*(Block.y/2 - CornerRadius),-Block.z/2])
cylinder(r=CornerRadius,h=Block.z,$fn=4*8);
for (i = [0:NumScrews - 1], j=[-1,1]) // screw holes
translate([-(Block.x/2 - CornerRadius) + i*ScrewOC.x,
j*ScrewOC.y/2,
-(Block.z/2 + Protrusion)])
PolyCyl(Screw[ID],Block.z + 2*Protrusion,6);
cube([2*Block.x,2*Block.y,Kerf],center=true); // slice through center
}
}
// Splice block less hose
module ShapedBlock() {
difference() {
SpliceBlock();
HoseProfile();
}
}
//----------
// Build them
if (Layout == "Hose")
HoseProfile();
if (Layout == "Block")
SpliceBlock();
if (Layout == "Show") {
difference() {
SpliceBlock();
HoseProfile();
}
color("Green",0.25)
HoseProfile();
}
if (Layout == "Build") {
SliceOffset = TestFit && !(NumScrews % 2) ? ScrewOC.x/2 : 0;
intersection() {
translate([SliceOffset,0,Block.z/4])
if (TestFit)
cube([ScrewOC.x/2,4*Block.y,Block.z/2],center=true);
else
cube([4*Block.x,4*Block.y,Block.z/2],center=true);
union() {
translate([0,0.6*Block.y,Block.z/2])
ShapedBlock();
translate([0,-0.6*Block.y,Block.z/2])
rotate([0,180,0])
ShapedBlock();
}
}
}
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