Justin Burnett Log

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This is work on redesigning the Quick Connect Wheel module for fabrication with the CNC Torch Table.

Update June 16, 2013

Created DXF files from Lucas' wheel mount assemblies. There are a total of 12 unique components between the three versions. A number of gaping standoff features have been added to the previous design. I am unsure of the design intent behind these features but the community has reviewed and approved these items in a design sprint which I was not able to participate in.

DXF Files:

I created the DXF files using the plug in referenced on http://opensourceecology.org/wiki/Sketchup_to_DXF_or_STL . Each face oriented in the vertical (blue) axis needed to be copied and pasted into another sketchup window, and rotated to lay on the red/green axis prior to selecting the face and exporting. The difficulty with exporting dxf files is that circles are exported as polygon approximations rather than as true arcs. I also downloaded a trial version of SkethUp Pro 8 – which (I thought) was supposed to export true curved surfaces. This however was not the case, and the dxf geometries were identical between the two methods of export. Exporting as a 3D model to .dxf format retained polygon geometries

Neither e-drawings nor cambam would snap to features created by this method, so I am unable to draw reference geometries to accurately place true circles. I'm sure that someone has solved this problem but for tonight, the software is winning...

Wheel mounts snip.PNG

BOMs:

1 7/8” Shaft Quick Attach Wheel Module (Left assembly, olive): (QTY 1 of each of the following)

  • Bottom Reinforcement Plate
  • Motor Mount Plate
  • Motor-side Bearing Mount – 2inch
  • Wheel-side Bearing Mount – 2inch
  • Central Attachment Plate
  • Side Reinforcement Plate
  • Top Frame Clamping Plate

3” Shaft Quick Attach Wheel Module (Center assembly, nright green): (QTY 1 of each of the following)

  • Bottom Reinforcement Plate
  • Motor Mount Plate
  • Motor-side Bearing Mount – 3inch
  • Wheel-side Bearing Mount – 3inch
  • Central Attachment Plate
  • Side Reinforcement Plate
  • Top Frame Clamping Plate

1 7/8” Shaft Quick Attach Wheel Module (Left assembly, Olive): (QTY 1 of each of the following)

  • Bottom Reinforcement Plate – Free Wheel
  • Motor-side Bearing Mount – 2inch
  • Wheel-side Bearing Mount – 2inch
  • Central Attachment Plate – Free Wheel
  • Side Reinforcement Plate – Free Wheel
  • Top Frame Clamping Plate

Update June 9, 2013

Wheelmount - edited 6-9-13.jpg

SketchUp Source File

Changes: Added 1/2" extensions to bearing and motor mount plates to aid setup and alignment of rear reinforcement plate. Also created additional slot and tab features to top frame clamping plate to prevent improper orientation during assembly. Vertical bolt hole were increased to 1" diameter, while bearing and motor bolt holes were increased to 5/8" diameter to accommodate 9/16" bolts with adequate tolerance.

Concerns: Top frame clamping plate slot and tab feature adds center seam which will need to be adequately filled with weld material. Voids could result in stress concentration and fracture nucleation site accelerating fatigue failure.

--Justin Burnett (talk) 05:55, 10 June 2013 (CEST)

Update May 27, 2013

Wheelmount - edited May 26, 2013.jpg

Source CAD File(SketchUp):File:Wheelmount - edited 5-26-13.skp

Notes: Added tongue and groove features to previous (February 3, 2012) quick attach wheel module assembly in order to increase manufacturability. Each slot is over sized by 1/32" in all dimensions while the mating tab is maintained at the chosen nominal value.

Concerns: Bolt hole sizes deviate slightly from those discussed during Design Sprint #3 on 5-26-13. These dimensions need to be confirmed.

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