Locking joint

friction-joint.js

function getParameterDefinitions() {
  return [
      { name: 'detents', type: 'int', initial: 12, caption: "Detents" },
      { name: 'holeDiameter', type: 'float', initial: 0.25, caption: "Bolt Diameter" }
      ];
}

function main(params) {
    var holeDiameter = params.holeDiameter;
    var detents = params.detents;
    return [
        makeFemalePlate({
            detentHeight: 0.10,
            holeDiameter:holeDiameter,
            detents:detents,
            allowance:0.020
        }),
        
        makeMalePlate({
            detentHeight: 0.10,
            holeDiameter:holeDiameter,
            detents:detents
        }).rotateX(180).translate([0,0,0.01])
    ]
    
}

function makePill(options) {
    options = options || {};
    var r = options.r || 0.125;
    var h = options.h || 1.0;
    
    return union(
        cylinder({
            h : h-2*r,
            r : r
        }).translate([0,0,r]),
        sphere({
            r : r,
        }).translate([0,0,r]),
        sphere({
            r : r,
        }).translate([0,0,h-r])
    );
}

function makeFlatPill(options) {
    options = options || {};
    var r = options.r || 0.25;
    var h = options.h || 0.125;
    var length = options.length || 1.0;
    var bl = length-2*r;
    var center = options.center || false;
    return union(
        cylinder({
            h : h,
            r : r,
            center : true
        }).translate([0,bl]),
        cylinder({
            h : h,
            r : r,
            center : true
        }),
        cube({
            size: [2*r, bl, h],
            center: true
        }).translate([0,bl/2,0])
    ).translate(
        center ? [0,-bl/2] : [r,r,h/2]);
}

function makeMalePlate(options) {
    var options = options || {};
    var detentOffset = options.detentOffset || 0.25;
    var detentHeight = options.detentHeight || 0.125;
    var outerDiameter = options.diameter ||  4.0;
    var hubDiameter = options.hubDiameter || 1.0;
    var detents = options.detents || 12;
    var thickness = options.thickness || 0.5;
    var holeDiameter = options.holeDiameter || 0.25;
    var outerRadius = outerDiameter/2.0;
    var hubRadius = hubDiameter/2.0;
    var allowance = options.allowance || 0.010;
    
    var spokeLength =  outerRadius - hubRadius - detentOffset*2

    var spoke = makePill({
        h : outerRadius-hubRadius-detentOffset*2,
        r : detentHeight
    }).rotateX(-90).translate([0, hubRadius + detentOffset])

    var spokeList = [spoke];
    var angle = 360.0/detents;
    
    for(var i=0; i<detents; i++) {
        spokeList.push(spokeList[spokeList.length-1].rotateZ(angle))
    }

    var machinedThickness = thickness-detentHeight;
    
    var plate = cylinder({
        h: machinedThickness,
        r: outerRadius,
        center:true
    }).translate([0,0,-machinedThickness/2.0]);
    
    var hub = cylinder( {
        h: detentHeight*4.5,
        r: hubRadius + allowance/2,
        center: true
    });
    
    var hole = cylinder( {
        h: thickness*3,
        r: holeDiameter/2.0,
        center: true
    });

    plate = union(
        plate,
        spokeList
    );
    
    return difference(plate ,hub, hole)    
}


function makeFemalePlate(options) {
    var options = options || {};
    var detentOffset = options.detentOffset || 0.25;
    var detentHeight = options.detentHeight || 0.125;
    var outerDiameter = options.diameter ||  4.0;
    var hubDiameter = options.hubDiameter || 1.0;
    var detents = options.detents || 12;
    var thickness = options.thickness || 0.5;
    var holeDiameter = options.holeDiameter || 0.25;
    var outerRadius = outerDiameter/2.0;
    var hubRadius = hubDiameter/2.0;
    var allowance = options.allowance || 0.010;
   
    var spokeLength =  outerRadius - hubRadius - detentOffset*2 + allowance
    detentHeight = detentHeight+allowance;
    var spoke = makeFlatPill({
        length : spokeLength,
        r : detentHeight,
    }).translate([-detentHeight, hubRadius + detentOffset, -detentHeight])

    var spokeList = spoke;
    var lastSpoke = spoke;
    var angle = 360.0/detents;
    
    for(var i=0; i<detents; i++) {
        newSpoke = lastSpoke.rotateZ(angle)
        spokeList = union(spokeList, newSpoke)
        lastSpoke = newSpoke;
    }
    
    var machinedThickness = thickness-detentHeight;
    var plate = cylinder({
        h: machinedThickness,
        r: outerRadius,
        center:true
    }).translate([0,0,-machinedThickness/2.0]);
    
    var hub = cylinder( {
        h: detentHeight*2,
        r: hubRadius,
        center: true
    }).translate([0,0,detentHeight]);
    
    var hole = cylinder( {
        h : thickness*3, 
        r : holeDiameter/2,
        center : true
    });
    
    plate = difference(
        plate,
        spokeList
    );
    
    return difference(
        union(plate,hub),
        hole
        );
}