pistons no longer sufficent to support weight

[Davimont]

a good day to all
I don't understand much, so I'm here asking for advice.

premise: I do not want to size the various components because it is not my job but only to understand what solution to propose to the maintainer who is dealing with the assembly.
I have a small existing structure (type lever bridge but with movement of about 10 degrees upward) that rises and falls thanks to two pneumatic pistons.
to this structure have added components to optimize a certain processing.

Now the problem.
the new components add weight to the system, from 30kg to lift with the original pistons now we have passed to about 50kg. the pistons lift the structure however but at the time of lowering it they can no longer shock the descent and then they knock everything on the machine below.

they do not want to replace the original pistons for reasons I ignore.
I've proposed dampers at the end of the race or flow regulators but it's not that I know exactly what I'm talking about, it's things I've never treated.

without more precise data perhaps it is impossible to propose a solution but to raise some advice on which components to evaluate I would be comfortable.

What could I propose to solve the problem?

place a very basic scheme made quickly with paint just to make the idea. in red the piston that raises and lowers the structure and in green the force that I have to fight to prevent the all anticipated without control.

 

[Fulvio Romano]

a mechanical spring that in mid-race exercises about 20kg that were added?

but these "additional components" constitute an increase in machine performance? So is it a substantial change? So you have to certify the car?

in fact slams. the machine directive was right that when the loads increase you have to remake the iter...

 

[TETRASTORE]

I see as a possible solution that you indicated, obviously depends on the load, the stroke and the point of application:
- fixed and variable calibration decelerators
- hydraulic shock absorbers with extension or compression brakingsee here.

 

[PIETRO2002]

Surely putting flow regulators and adjusting them to the limit helps, but this decreases the speed of movement, depends if it can suit you. Even the solution to put end-race decelerators can help.

 

[stevie]

The end-of-the-race dampeners are the ideal solution...even because I believe that the flow regulators at the unloading of cylinders are already there (at least I hope so, otherwise I believe that they "slam" on the structure).

 

[Davimont]

a mechanical spring that in mid-race exercises about 20kg that were added?

but these "additional components" constitute an increase in machine performance? So is it a substantial change? So you have to certify the car?

in fact slams. the machine directive was right that when the loads increase you have to remake the iter...

the machine is a prototype in development for several years and I think it hasn't been certified yet.
I don't know how things are.

However the addition does nothing but change the path of a paper tape to improve the adhesion to the upper roller. in the schematized image the first and after modification.

I see as a possible solution that you indicated, obviously depends on the load, the stroke and the point of application:
- fixed and variable calibration decelerators
- hydraulic shock absorbers with extension or compression brakingsee here.

Thanks, then I didn't go too far.
the thing that makes me angry is that they claim to move it without too many changes but if you add the weight it is normal then adjust everything else to the resulting situation!

Surely putting flow regulators and adjusting them to the limit helps, but this decreases the speed of movement, depends if it can suit you. Even the solution to put end-race decelerators can help.

Yes, there are no demands for speed at this stage and the movement takes place only in case of roller change but happens a few times a week.

The end-of-the-race dampeners are the ideal solution...even because I believe that the flow regulators at the unloading of cylinders are already there (at least I hope so, otherwise I believe that they "slam" on the structure).

I confirm that there are already flow regulators but even if adjusted to the minimum they are not enough because they are now under sizing.

 

[Mario SJPD]

the thing that makes me angry is that they claim to move it without too many changes but if you add the weight it is normal then adjust everything else to the resulting situation!

If you do not want to change the mechanics the only alternative and change the pressure to the cylinder there are pressure multipliers to be mounted near the use.buy pressure multiplier online | festo itare a bit noisy but if the problem is only the force maybe they can solve.

 

[Davimont]

If you do not want to change the mechanics the only alternative and change the pressure to the cylinder there are pressure multipliers to be mounted near the use.buy pressure multiplier online | festo itare a bit noisy but if the problem is only the force maybe they can solve.

Thanks I didn't know them.
the problem however is not to raise the additional mass, the existing ones already do it even if under sizing.

instead I have to solve the speed downhill, having to stop a few millimentri from the existing structure has to slow down and instead goes to slam.

This is what they told me because I have not yet gone to check in person.

 

[Mario SJPD]

instead I have to solve the speed downhill, having to stop a few millimentri from the existing structure has to slow down and instead goes to slam.

if the cylinder has more pressure develops more strength in both movements (I hope it's a double effect and that it sets the flow regulators in exhaust) so you should be able to put yourself under the same conditions as you had before weight gain, allowing you the same slowdown you had before.

 

[Davimont]

if the cylinder has more pressure develops more strength in both movements (I hope it's a double effect and that it sets the flow regulators in exhaust) so you should be able to put yourself under the same conditions as you had before weight gain, allowing you the same slowdown you had before.

I will also look at your solution.
Thank you.

 

[Mario SJPD]

I will also look at your solution.

It's a possibility, but unless it's impossible, I'd also opt to insert some dampeners.

 

[teseo]

according to me they have mounted the flow regulators on the contrary not in exhaust but in load, if the piston succeeds to lift the load then it must be able also to lower it, without knocking.....

Maybe you don't need to change anything if you don't properly calibrate the existing circuit, check that there are no losses in the circuit since if the flow regulators are closed (as you said also closed to the minimum slam), bangs well then there is some loss; with the closed flow regulators you shouldn't move the cylinder. .
and then I would check the sense of assembly of flow regulators. . .


ciao

 

[bip]

increase air pressure, if the cylinder is double effect, it worsens the situation, as the cylinder "tires down" faster.
If you want to slow down the downward movement, you don't have to put the strokers on the downward movement, but on the upward movement: in this way, the room that pushes upwards, slowly empties and makes it a pneumatic spring.
many mistakes thinking of slowing down the descent by choking the tube that pushes down, but in this way they only get a slight depression inside the cylinder, while the counterpression in the opposite chamber is much more effective.

if the problem is in the last stretch of racing, normally the pneumatic cylinders have an adjustable brake just to damp the end of the race, basically they go to create friction on the stem in the last millimeters of racing.

also evaluate to add a counterweight, if you have the possibility, to balance the arm and reduce the load on the cylinder

 

[Mario SJPD]

increase air pressure, if the cylinder is double effect, it worsens the situation, as the cylinder "tires down" faster.

thanks bip, I had not been complete, I meant to increase the pressure only in the lifting room, but to take nothing for granted, should allow you a climb , a station and a braking less dependent on the weight (whose increase and cause of your problem) of course the micro-regulators should be put on the discharge as from the scheme of teseo

and then I would check the sense of assembly of flow regulators. . .

This is definitely the first thing to do.

 

[Davimont]

Great snacks!
the next step then is to go to see what type of pistons are installed to understand whether to single or double effect and verify that the flow regulators are mounted in the right direction.

 

[Davimont]

here are the two pistons mounted on the machine, they run really short.
Unfortunately the machine is now working (without the new part) and so I could not do any tests.

 

[teseo]

ok from here you understand at least that they are double effect pistons, there are flow regulators, but you do not understand the type, see if there is a code and laughter to the type or post that we see of what type they are.... they look like the chamois.... .

 

[Mario SJPD]

look like camozzi ..

you are chamozzi, the same type there are bi-directional or unloading serves the code to distinguish them.

 

[teseo]

analyzing the photo seems to see a c stamped on one of the two flow regulators, but on you see the other, you can confirm that it is a c, because if so it is then, we are from head that is the circuit is correct............it is necessary to understand what is wrong, that it is broken or that it does not work correctly:

- checking if turning the screw of flow regulators the speed changes? If you mean they work if not, it could be broken, they should be replaced with new ones.

-I close all the flow regulators, the system moves, if you then there is some loss maybe they are the flow regulators that are broken, also controls the tubes and valves

-the flow regulators are too big for the esigua stroke that has that piston
the regulators who have chosen are of a somewhat dated series, I would replace them with this which has a more homogeneous adjustment curve, if you want to stay on chamois otherwisesmc makes specific versions for low speeds here you see an example I put the configurator link https://www.smc.eu/it-it/prodotti/t...s-fm-fc~165684~cfg?partnumber=as2201fm-01-06a

ciao

 

[Davimont]

Thank you very much for the tips!
I wanted to ask you: what is the meaning of the c you were talking about?

I don't think there's anything on the regulators.