114 lines
3.4 KiB
Plaintext
114 lines
3.4 KiB
Plaintext
![]() |
// Shelf Bracket
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// This is a bracket that holds a shelf. It is made of aluminum and is designed to hold a force of 300 lbs. The bracket is 6 inches wide and the force is applied at the end of the shelf, 12 inches from the wall. The bracket has a factor of safety of 1.2. The legs of the bracket are 5 inches and 2 inches long. The thickness of the bracket is calculated from the constraints provided.
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// Set units
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@settings(defaultLengthUnit = in)
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// Define constants
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sigmaAllow = 35000 // psi (6061-T6 aluminum)
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width = 6
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p = 300 // Force on shelf - lbs
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factorOfSafety = 1.2 // FOS of 1.2
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shelfMountL = 5
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wallMountL = 2
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shelfDepth = 12 // Shelf is 12 inches in depth from the wall
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moment = shelfDepth * p // assume the force is applied at the end of the shelf to be conservative (lb-in)
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filletRadius = .375
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extFilletRadius = .25
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mountingHoleDiameter = 0.5
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// Calculate required thickness of bracket
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thickness = sqrt(moment * factorOfSafety * 6 / (sigmaAllow * width)) // this is the calculation of two brackets holding up the shelf (inches)
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// Sketch the bracket body and fillet the inner and outer edges of the bend
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bracketLeg1Sketch = startSketchOn('XY')
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|> startProfileAt([0, 0], %)
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|> line(end = [shelfMountL - filletRadius, 0], tag = $fillet1)
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|> line(end = [0, width], tag = $fillet2)
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|> line(end = [-shelfMountL + filletRadius, 0])
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|> close()
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|> hole(circle(
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center = [1, 1],
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radius = mountingHoleDiameter / 2
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), %)
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|> hole(circle(
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center = [shelfMountL - 1.5, width - 1],
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radius = mountingHoleDiameter / 2
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), %)
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|> hole(circle(
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center = [1, width - 1],
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radius = mountingHoleDiameter / 2
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), %)
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|> hole(circle(
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center = [shelfMountL - 1.5, 1],
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radius = mountingHoleDiameter / 2
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), %)
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// Extrude the leg 2 bracket sketch
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bracketLeg1Extrude = extrude(bracketLeg1Sketch, length = thickness)
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|> fillet(
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radius = extFilletRadius,
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tags = [
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getNextAdjacentEdge(fillet1),
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getNextAdjacentEdge(fillet2)
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]
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)
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// Sketch the fillet arc
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filletSketch = startSketchOn('XZ')
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|> startProfileAt([0, 0], %)
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|> line(end = [0, thickness])
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|> arc({
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angleEnd = 180,
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angleStart = 90,
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radius = filletRadius + thickness
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}, %)
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|> line(end = [thickness, 0])
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|> arc({
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angleEnd = 90,
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angleStart = 180,
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radius = filletRadius
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}, %)
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// Sketch the bend
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filletExtrude = extrude(filletSketch, length = -width)
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// Create a custom plane for the leg that sits on the wall
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customPlane = {
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plane = {
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origin = { x = -filletRadius, y = 0, z = 0 },
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xAxis = { x = 0, y = 1, z = 0 },
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yAxis = { x = 0, y = 0, z = 1 },
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zAxis = { x = 1, y = 0, z = 0 }
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}
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}
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// Create a sketch for the second leg
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bracketLeg2Sketch = startSketchOn(customPlane)
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|> startProfileAt([0, -filletRadius], %)
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|> line(end = [width, 0])
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|> line(end = [0, -wallMountL], tag = $fillet3)
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|> line(end = [-width, 0], tag = $fillet4)
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|> close()
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|> hole(circle(
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center = [1, -1.5],
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radius = mountingHoleDiameter / 2
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), %)
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|> hole(circle(
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center = [5, -1.5],
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radius = mountingHoleDiameter / 2
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), %)
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// Extrude the second leg
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bracketLeg2Extrude = extrude(bracketLeg2Sketch, length = -thickness)
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|> fillet(
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radius = extFilletRadius,
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tags = [
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getNextAdjacentEdge(fillet3),
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getNextAdjacentEdge(fillet4)
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]
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)
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