Mechanical solution for the translation of heavy systems

3D Design Volume Model
1

Hello designer friends!

 

For my first post, I submit a problem encountered at my work.

 

I have to make a system that allows the movement of 3 sets along a guide table (1m of displacement on average).

Each of these sets is very heavy (1t for the biggest) and each one must have a displacement independent of the others.

The working conditions are those of a rolling mill: high temperatures, heavy watering with cooling water, presence of scale and projection of parasites (materials, filings, etc.).

In addition to the displacement, a fine adjustment must be possible (about 100mm of runout).

Finally, this system will have to be entirely mechanical.

 

To meet these criteria, I chose to treat fine tuning and displacement separately.

Each set will therefore be separated into two subsets.

 

For the adjustment, I chose to use two pressure screws (with a low pitch) in contact on a sole (1st sub-assembly adjustable with precision from left to right)

This sub-assembly is placed and clamped on an intermediate piece (under sole or on bed base as you want ^^) which is itself in contact with the table.

 

Where I get stuck is to find a translation system that will make the 3 sets move independently of each other.

 

My best idea is to use a worm screw (protected) with a clutch nut placed on each assembly however given the ambient conditions, this solution was ruled out ...

 

I had thought of fixing the sets on bronze pads in order to move them more easily and manually but 60Kg of thrust is still too high ...

 

The rack and pinion system is to be forgotten and in general all systems that no longer work as soon as chips are present are to be discarded

 

I also thought of a system of separate pulleys for each box but it becomes too complex...

 

The best would be an ultra-simplistic solution but one that works. Using pressure screws would have been the best but the elements have to move 1m on average which is way too much ...

 

So if anyone has an idea, a revelation or a system that is unknown to me to share, it would be super nice!

Thank you in advance and have a good day to you

 

Morgan

2

uh, really not easy given the conditions imposed...

I'm going to think about it, because right now, I have no idea that comes to mind.

 

Yves

1 Like
3

Hi @ morgan

can you make a diagram or a screen of your 3 sets

which are to be guided along a table

@+

4

I don't see the system completely yet, but here are some ideas to explore:

Hydraulic cylinders (with the fluid that goes well for high temperature)

Rollers under assemblies with a low slope

Motorized rolls

5

Hello

 

For me, the idea of a worm screw should not be dismissed. Let me explain given the operating conditions why not move the translation system away from the hot spot and therefore the risks (the conditions can be less hot at one or two meters) after the clutch nuts would be connected to the different assemblies by profiles which will have no risk with the conditions.

 

hoping to have made progress in the debate.

 

Kind regards

 

Bastien

6

The system reminds me a bit of the machine tools, like a machining center, right?

so if we get closer to the guides used on machining centers (cast iron rail with oil film) and worm movement it could stick right?

2 Likes
7

Thank you for your answers!

 

  I enclose a little diagram. The blue box is one of the 3 systems (it's the most imposing)

The table is in green and the two black cylinders are rolling cylinders.

The material goes hot in the box and goes directly into the fluted cilyndre to have a new shape.

The idea of ellosizing the system is therefore not possible (even if it was a good idea)

 

For now, I'm sticking to the worm screw solution, my boss told me to forget about it but he's changing his mind a lot^^

 

I also thought about the pebbles but I think it won't be easy for the guidance since the green enj table will quickly get dirty

 

I may dig into the idea of the jacks, it's a bit expensive and I need to see the customer fittings but it can be quite good...

 

I'll see with my boss at the next meeting...

 

In any case, thank you and if you have any other ideas, I'm all for it!

 

Have a good day

Morgan

 


sans_titre.bmp
8

Hello

 

Have you looked at the solution of ball bushings on guide rails? The advantage of the system is to withstand high loads with a travel facilitated by the ball bushings

 

@+

Denis

9

I thought exactly the same thing as you@dpusel

 

10

there are at least 2 of us who have the same idea!! But is it the right one?

11

Hello

If your table is smooth, you can maybe put your blocks on load-bearing balls (placed under the ball block at the bottom). You may need to provide a kind of scraper on each side so as not to be bothered by the largest debris. Your table must also be hard enough on the surface.

If it works, you should be able to move by hand.

 

 


bille-porteuse.pdf
1 Like
12

The solution of ball bushings + rail seems very good to me!

I put it aside!

 

The only problem is at the level of chip-style parasites...

I'm not sure that this system works properly if there is dirt on the rail...

Customers don't want to clean the system every time they do it

 

It's the same problem for the idea of the balls (which is not bad either), they would already have to be made of stainless steel (too expensive) not to be oxidized and moreover the chips could block the whole thing I think ...

13

I just inquired with a supplier, the rails + bushings can be treated anti-corosion and equipped with reinforced scrapers! :) I think the miracle solution has arrived!

Thank you very much for this idea I will make the plans and talk to my boss, I will keep you informed;)

14

Hello

 

To protect the guide shafts, there are metal spiral guards.

http://kabelschlepp.fr/fr/produits/protections/protections-spirales/index.html

Be careful with the size of the trees to support 1 ton.

 

See if ball skate and rail type guides can hold the heat. Combined with a telescopic rail protection or scrapers, it can be suitable. The advantage is that the rail is supported by the machine frame.

 

1 Like
15

For me, load-bearing balls, even stainless steel, will be cheaper than rails and I think they will withstand the aggressive environment better.

 

16

I'm also going to draw a ball solution because I might be right in terms of space for the rails and the temperature should not exceed 80° for their operation to be guaranteed.

Do you have an example of a system based on marbles that could inspire me? I've never designed a system like this yet and it could help me

17

See this link among others

http://www.boschrexroth.com/country_units/europe/france/fr/produits_applications/translation_montage/rep_download/lt_catalogues/R310FR_2910.pdf

Give us news

@+ ;-)

18

Hello, I'm here to give you an update on the rest of my project.

 

After meeting, it turned out that the systems will take about 3 kilotons of pressure at the rear while in my worst case scenarios, I thought there would be a maximum of 3 tons .... I was still far from it!

 

The rail system is therefore abandoned.

 

I'm finally going to try to make a set carried by balls with a system that allows the balls to fit into the sole.

In this way, when the whole thing is placed in the right position and bridled, the underside of the sole will serve as a support instead of the balls that would take too much effort. 

 

For the moment this is the best solution  my problem.

I will keep you informed if this solution has been approved.

 

Have a good day to you

19

3000 tons!? That's huge. Do you work under a giant press? (or would it be 3 kilos Newton?)

 

Otherwise, for a retractable system, and since you only go in one direction, maybe cast iron casters would be more practical.

20

Hello.

The first way to move such a heavy load is to make it roll.

For a straight movement there are "cam rollers on axis".

2 types:*cylindrical outer cage = cheap but implies a nikel installation plan so machined

* outdoor cage with large radius = more expensive but can be mounted on a welded mechanical frame.

 

Then the movement.

Here again, there are several solutions

 

Telescopic cylinder, geared motor + rack or winches.

 

The last point that will condition "the engine": precision

What is the order of magnitude: 2 to 10cm, 1mm, 0.1mm? 

 

Last point. Is precision required for the entire stroke of the table or for the precise part?