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brandon26
6th Jun 2006, 06:08 AM
I have to design a construction for a baby buggy.
I am trying to find a way to connect two pieces of aluminium tubes together. I could weld them together, but I also want the joint to allow the tubes to move (so the baby buggy is foldable). Is pop riveting a good method?
Does anyone have a better or more efficent suggestion?

Can someone also provide me with tips on how to make the buggy foldable?

Very urgent help required.:confused: :confused:

Andy Mac
6th Jun 2006, 09:35 AM
Hi Brandon,
Even though you can get long pop rivets they won't work too well joining two al. tubes together, especially if you want the joint to pivot. Pop rivets rely on pressure as in squeezing two parts together, meaning tight joints or deformed tubes. Solid flat bar can be made to pivot, especially if you leave a gap between the parts via a removable shim, or a low friction washer in between. The other downside with pop rivets is the gnarly end left after extrusion, which would be an H&S issue...especially with kids equipment.
You are better off using a bolt with a Nyloc (self locking) nut, or most prams and buggies etc seem to use a solid rivet or pin at their joints, with a peened over end. I guess they have a dimple in the end to enable a decent spread or mushroom, when peened.
Hope this helps!

Grahame Collins
6th Jun 2006, 09:50 AM
Hi Brandon
You say the baby buggy has to fold up.To obtain the strength required for the buggy I would be careful in not making the tube diameters too small.

This in turn, limits the pull length of the rivetts. A better solution may be to use small diameter s/s high strength bolts with nyloc friction nut inserts.
Using the bolted design you could put parallel plates either side of the tube and obtain much better strength. Keep the Nuts to the outside and cut and file the excess bolt to avoid damage to baby's fingers.

I ve used rivets in the past for a folding toolbox, but the rivet pull length was short and I did place washers under the compressive ends of them.

You may also have to consider a shaped washer to spread the load area over your tube radius to avoid the point loading avoid crushing the tube.

Is there a specific reason you are not going with one off the great designs available these days? If dealing with such a precious cargo surely saving a dollar or two can,t be such and issue.Its hard to offer advice when one is possibly dealing with only a part of the information required to offer an opinion.

Grahame