operation of telescopic tubes

[Attilone1]

I was wondering if any of you ever had to design a telescopic tube like those used in mobile cranes.

to me they asked to make one, two rectangular tubes driven by a cylinder (telescopic of course), the thing will work almost vertical (10-20 degrees) and will have to lift a few hundred pounds including the weight of the pipes.

My doubt is about how to make the pipe guide to avoid metal-metal contact, at the moment my best thought (however, to say) is to put anti-friction elements between one tube and the other in anti-friction material (some type of plastic but not yet which), from the attached design you should better understand the idea.

Now the problem is that the pipe will be mounted in a very difficult accessible area and will be operating practically 24/7 so they are looking for a friction material that lasts a lot or an alternative method to achieve the flow between the pipes, from here back to the initial question: How the hell are the telescopic pipes of the mobile cranes like the manitou? I can't find anything on the net that I had to invent that system, but I don't know if it can work in the real world where the friction is your enemy. .

 

[meccanicamg]

the best thing if you are not a hydraulic cylinder designer is to buy one already done, since then you should certify it and if it is not your bread you would fall into big evaluation mistakes and who puts the signature on the project has civil and criminal liability.

you will realize the square tubes that parade, someone else will sell you the telescopic tube. It is also true that you could think of using only one square platform at the end and directly use the telescopic cylinder from trade.

If you want to carry out the parade guide with the tubes you just have to realize them as the sliding guides that stick to matriosca of the axes guides of the numerical control cutters. with one or more series of rollers spinning and making from anti friction elements.

 

[zeigs]

that I know the arms of the cranes, including manitou, are iron on iron, at the limit with brass or bronze skates, with an addition of so much grease to make from lubricant
for low loads you can think of teflon skates, which of its has low friction

 

[PaoloColombani]

At the moment my best thought (whether it is done to say) is to put anti-friction elements between one tube and the other in anti-friction material (any type of plastic but I still don't know which)

in this field is widely used the nylatron, other is that the commercial name of a nylon 6 casting with addition of molybdenum bisulfur. Obviously it is not the only usable technopolymer.

from here return to the initial question: How the hell are the telescopic pipes of the mobile cranes like the manitou?

at least the last are constituted by two shells that once welded go to form a section of type pentagonal, at the end the vent of the telescope is guided by skates that if I do not remember badly they are in plastic material (but I do not know which), however they are recordable; look at them closely you see the log screws well. I know that other manufacturers use it in nilatron because they declare it in technical specifications and brochures.

I don't know if you've realized this, but I think they've asked you to develop a new application (at least for you and for them). think well about the risks and also think about protecting you. I still recommend that you start with a good search.

 

[PaoloColombani]

p.s. internet is just an oracle, just use the right questions. I just tried to put on google these keywords:

nylatron roller skates

I seemed to see that many ideas appear, I dare not think how many other results trying with the words in English.

 

[radio]

we take it for granted, as mechanicalmg says that the plumber purchases from catalog or you do it as specialized companies; I confirm what it says paolocolombani, tubular in two semigusci section and the nylatron (pa6+mos2) is almost always the most suitable material.
I say almost always because, being thermoplastic, it suffers the relatively high temperatures, environmental and/or those induced by friction.
should not be your case, since the telehandlers will work almost vertically, in the doubt however not to soothe on the surface of the support and the length of the tubular frame to parade.
Another point is lubrication, it is true that nylatron has self-lubricating properties, but it is appropriate to predict periodic, manual or automated fattening.
alternatively bronze is usable, no problem with operating temperatures and can better endure dry operation, but being much more rigid is not able to adapt to small disalignments of a tubular than the other, with the consequence that you could find with the male that, all extended, rests on the edge of the skate, with potentially disastrous consequences; unless you try to mount guides on sticky supports, but you go to complicate life and if it is not strictly necessary let it go.
Moreover the hardness of the bronze, long go, could significantly wear the tubular in the crawling area; to remedy this you should use for tubular steels like weldox 700 or higher.

Bye.