Telescopic Strut.

[gruntguru]

I am looking for a telescopic strut for a marine application (think camera tripod or monopod). I need it to collapse to 800mm or less and extend to 1800mm. Max load is 100 kg axial. Problem with available tripods they all seem to have friction locking only. I need positive locking (pins perhaps?) but without backlash (so it needs friction or clamping as well).

The strut will act as one leg of a tripod for towing a sub-surface apparatus. Depth of the apparatus will vary from 600 mm to completely out of the water.

Alternatively a linear actuator (either 12v or manual) that meets the above specs might do the job.

je suis charlie

 

[BEMPE16524]

not sure if something like this may help:

http://www.unistrutohio.com/telescoping-square-tube/

 

[GregLocock]

I don't like them as mechanisms but crutches are adjustable vis spring loaded pins and of the right load capacity. So you'd need to add a friction clamp to them. You might need to be a bit picky on materials, SS304 is too likely to corrode for use as a sliding tight fit.


Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[EdStainless]

There are lead-screw-in-channel types of devices, like this

http://www.ebay.com/itm/Vintage-Tri...-Crank-Knob-Allstate-from-Sears-/131777275886

Then you could adjust it and and it would stay in place. You could motorize it if you wanted to.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

 

[drawoh]

gruntguru,

If you absolutely require a reliable friction clamp, you don't need the positive lock, except perhaps as a fail safe device.

Could you use a hydraulic or pneumatic ram extended to solid height?

--
JHG

 

[GregLocock]

Is the positive lock to provide fixed increments of length?

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[berkshire]

Have you looked at a modified adjustable length spinnaker pole?
B.E.

You are judged not by what you know, but by what you can do.

 

[gruntguru]

Thanks all.
Greg, I forgot to mention. Length needs to be adjustable in increments of 100mm (4") or less.

je suis charlie