Somehow (and don’t ask me how) my family have turned into avid tent campers, going every couple of weeks over the New England summer. But as with anything in my family, nothing ever goes smoothly; let me tell you about how SolidWorks was able to save our camping holidays.
As with many modern tents mine is made up of a simple frame of bent flexible poles and nylon fabric. The frame poles are built up of rod segments, which are held together by a collar and an internal elastic cord. These rods are very flexible, bending over large radii but quite weak when subjected to local bending, as I found out when one was stepped on by accident. The rod didn’t break but is was certainly weakened enough that I couldn’t be sure that it wouldn’t collapse the next time I put the tent up or maybe the time after that. What to do? Get a new tent? Scour online for a spare pole? Break out the duct tape and hope for the best? With only a few days to go before we left my purchasing options where limited, so it was time for a SolidWorks solution.
What I needed was a simple splint that would locally stiffen the rod, but which was still thin enough to fit inside the tent pole sleeve. It would be a simple piece of geometry, the only complication being how I would attach it to the rod and how it would be made. Because of the way the tent pole is made up of segmented rods I couldn’t slip the splint down the pole and have the clearance I wanted for support so I decided to make it in two halves. At SolidWorks we have a rapid prototyping machine that can turn out very accurate plastic components, but because the plastic is made up layer by layer there can be a question against the strength of the plastic when the loading induces principal stresses in the plane of the plastic layers. As I wanted to ensure that the splint would be strong in bending along its axis, I decided to print the splints along the axis of the part rather than across it.
To fix the splints in place, while at the same time strengthening the splint radially, I planned to wind some of my son's fishing line around two halves with a coating of epoxy glue. The splint was also was designed with a slight interference between the rod and splint at the ends, to grip the rod and to stop the splint sliding away from the point of weakness. It has actually taken me a lot more time to write down the design process than actually design the splint in SolidWorks, after which I emailed it down to the Tech Support guys downstairs. The next morning two pairs of splints where waiting for me on my desk.
Suffice to say my design worked, the tent stayed up and our camping holidays last year were saved thanks to SolidWorks 😉
Now all I need to design is a mosquito repelling force field and the trips would be perfect. Hhhmmm..