HELP! Tripod Repair

[joe greiner]

Does anyone know the secret handshake for assembling telescoping tripod legs?

One leg of my Velbon T-3500 tripod escaped with gravitational assist. The parts seem to be intact. The USA distributor is closed for the weekend.

I can still use the tripod, with shorter legs, and/or buy a new tripod. But I'd prefer to repair this one, because of other features such as the quick-release camera mount, and the rising centre post.

I suspect other tripods use similar construction. Any help will be gratefully appreciated.

Joe <2008_11_01/xx10, xx11

[bsrlee]

For some reason I have this dreadful feeling that your two pieces should be one piece :C I had a quick look at mine and I can't even see the retaining key - I'm guessing that it is normally hidden inside the cam lock.

If so, you will have to screw or otherwise pin the long bit to the short bit (probably one of the 'unglueable' plastics) then insert it back into its hole so the short bit goes in the inner hole, then force the cam lock over the assembly to hold it in place.

[joe greiner]

Thanks bsrlee.

I don't think they've broken apart. On a first attempt, I found a chamber within the latch that could receive the large piece. I wasn't sure which way the small end notch should face (might not matter of course). Holding that chamber downward, I placed the latch on the inner tube. Then rotated it to place the small rectangular hole upward. The smaller piece has a block which engages the rectangular hole in the inner tube, so I placed it there with the block inward. Then pushed the assembled inner tube into the outer, beyond the opening in the outer, to secure the small piece. I rotated the tripod back to set the chamber below again.

Then I tried to shove the latch onto the outer, and could neither engage it nor go all the way. Naturally, it shouldn't be a loose fit, or it'd continue to fall apart.

I fear that thermal expansion of the latch, or freezing the outer tube, might be needed to create a shrink fit; temperatures could be critical too, to prevent melting the plastic latch. Telephoning the distributor on Monday might provide some insight, or indicate that professional repairs and shipping each way to New Jersey would be more expensive than a new tripod. In the meantime, the tripod is still usable, though somewhat short. A last resort could be to browse the US Patent Office database - patent specifications are supposed to be usable by those "skilled in the art," whoever they might be.

Joe

[joe greiner]

It turns out that the patent search struck gold - sort of. Velbon has had only 32 patents assigned, and one of them, 4932622, is spot on for the leg lock of the T3500. 'Twas just as well I searched for "Velbon," because a first search without Assignee used "latch" instead of "lock" without success. The patent is silent on a construction sequence, though. And the small piece (rectangular) is only indicated as round, without an identification number or any mention of its significance.

I think I was utterly wrong about the first procedure and any need for thermal operations. For my second attempt, I placed the latch on the outer tube, and then put the large piece into the chamber from the exposed end of the outer tube. I put the small piece onto the inner tube and presented it to the opening. It was obvious that the small piece couldn't go past the large piece protruding into the inside of the outer tube. So I made a "shoehorn" from some salvaged street sweeper bristles, filed thin. I set the shoehorn over the small piece, extending well beyond the end, and secured it to the inner tube with two pieces of tape. This allowed the subassembly to be urged into the outer tube. I removed the tape and withdrew the shoehorn. Unfortunately, the inner leg doesn't stay inside the outer. I suspect that the gravitationally-assisted escape might have deformed some of the parts enough to reduce their integrity.

Having invested more time than a new tripod could possibly cost me, even at slave labour rates, I'll be shopping for a new tripod; which I'll test in the store, of course.

It sure was fun, though, trying to solve this puzzle.

Joe <2008_11_03/xx14, xx16.jpg

[bsrlee]

Sounds like a perfect hobby pursuit - it takes a lot of time and/or money, and doesn't pay for itself in any way. :U