flag crane project

[@neipolos]

Bye to all,

My name is alessandro I attend the first year of a course its mechatronics. as the first project work, witnessing the work done so far, I am designing a flag crane destined to the naval sector (precisely for the watering of boats). the starting data at my disposal, in addition to the purpose of use of the crane, are the following:
Column height: 5m
Arm length: 4m
max capacity: 2t
for the sizing of the arm I selected an ipe 360 profile, while for that of the column a circular hollow profile with external diameter 406,4mm and thickness 7,1mm.
My problem at this point is to design an arm rotation system that can be connected to an electric motor. I wondered if it could be a suitable solution to exploit the following example (see photo) by connecting the rotation pin (prolonged) through coupling to a motor fixed to the column of the crane.

alternatively I found this other example, where I think you could transmit rotation from the engine (always placed on the column) to the arm through a large toothed wheel placed in the junction.

thanks in advance for the help!

 

[Exatem]

Bye to all,

My name is alessandro I attend the first year of a course its mechatronics. as the first project work, witnessing the work done so far, I am designing a flag crane destined to the naval sector (precisely for the watering of boats). the starting data at my disposal, in addition to the purpose of use of the crane, are the following:
Column height: 5m
Arm length: 4m
max capacity: 2t
for the sizing of the arm I selected an ipe 360 profile, while for that of the column a circular hollow profile with external diameter 406,4mm and thickness 7,1mm.
My problem at this point is to design an arm rotation system that can be connected to an electric motor. I wondered if it could be a suitable solution to exploit the following example (see photo) by connecting the rotation pin (prolonged) through coupling to a motor fixed to the column of the crane.
alternatively I found this other example, where I think you could transmit rotation from the engine (always placed on the column) to the arm through a large toothed wheel placed in the junction.
thanks in advance for the help!

not having well understood the first, opto for the second system.

 

[@neipolos]

in the first system I thought to create a whole between arm and pivot (which rotates therefore thanks to two ball bearings cast in the joints), prolong the pin so that it goes down along the column, and connect it somehow to the electric motor (network or joint)

 

[@neipolos]

hi to all, I am finishing the project (I eventually opted for a rotational ring between arm and column) but I still have a question for you: I have a doubt about the welds, both for the one that join base plate/column, and for those that join upper plate/arm (i.e. trave ipe360).
Therefore, both should be simplified at the moment, so the max grazing sigma on them is given by mf/wf. the problem is this: if the welding does not resist and then I go to strengthen the structure with welded handkerchiefs, for example, between column and base plate, how to calculate then the wf of the new figure I get? (in this case it will be a sun-shaped welding, a circle surrounded by rays as you can see also in the pictures above)

thanks for the help

 

[Exatem]

hi to all, I am finishing the project (I eventually opted for a rotational ring between arm and column) but I still have a question for you: I have a doubt about the welds, both for the one that join base plate/column, and for those that join upper plate/arm (i.e. trave ipe360).
Therefore, both should be simplified at the moment, so the max grazing sigma on them is given by mf/wf. the problem is this: if the welding does not resist and then I go to strengthen the structure with welded handkerchiefs, for example, between column and base plate, how to calculate then the wf of the new figure I get? (in this case it will be a sun-shaped welding, a circle surrounded by rays as you can see also in the pictures above)

thanks for the help

It could be that I understood badly but it seems to me that in this case the welding is pressed to traction. If so, a welding length above the necessary section must be achieved.
This is a means of lifting, perhaps it would not be bad to subject the same to a control perhaps through penetrating liquids.

p.s. rethinking, if you add the braces (which I would always put) in fact the vertical stretch of the welding is subject to bending and cutting.
If you are looking for mesh, you will find many dispenses on the topic.

However reasoning practically, if you correctly sized column and beam, welds will have sez. greater and therefore greater resistance. what makes welding critical, when well performed, is not the cord itself, but is the thermal stress of the affected areas.
For high-strength steels, preheating zones are performed but I don't think it's your case.

 

[@neipolos]

It could be that I understood badly but it seems to me that in this case the welding is pressed to traction. If so, a welding length above the necessary section must be achieved.
This is a means of lifting, perhaps it would not be bad to subject the same to a control perhaps through penetrating liquids.

p.s. rethinking, if you add the braces (which I would always put) in fact the vertical stretch of the welding is subject to bending and cutting.
If you are looking for mesh, you will find many dispenses on the topic.

However reasoning practically, if you correctly sized column and beam, welds will have sez. greater and therefore greater resistance. what makes welding critical, when well performed, is not the cord itself, but is the thermal stress of the affected areas.
For high-strength steels, preheating zones are performed but I don't think it's your case.

Forgive me exatem but I don't follow your speech. I ask that my knowledge on this matter is very small, so I have to ask you further questions
First of all, we examine only the basic welding (i.e. that between base plate and column) so we do not make confusion. between column and base plate the compote stress should be solely disconnection or weight of the load + weight of the crane itself (compression) and bending moment given by the load and the arm (flase). So why do you suggest to check the traction welds?
subsequently, I did not understand the speech regarding the sizing: What relationship is between column size and beam and weld resistance, do you refer to the thickness of the profiles?
Finally, I remain doubtful about the wf of the welding, which to be clearer you I sketched now in 10 seconds on paint
How do you calculate the wf of this figure?

 

[@neipolos]

Okay, I'm not a magician with your computer, you understand if you click on the image and enlarge it you see

 

[Exatem]

See if this spreadsheet can help you.
View attachment Verifica bulloni e saldatura a cordone d'angolo NTC 2008.rar

 

[@neipolos]

ehm, decisively in the :redface:

 

[@neipolos]

I rectify everything!!!! I had made a very trivial error in the calculation of the bending resistance module, in fact the circular welding held

 

[@neipolos]

or better, I had to increase the thickness of the profile to 16 mm. In this way I could increase welding to 12

 

[Exatem]

Now I don't have time to post patterns and drawings and I can't even get too far into the subject, but I still don't understand one thing.
leaving for a moment the braces, the welding between the column and its base is a circular crown having as section the section of the welding cord.
this crown is subjected to normal effort depending on the position of the arm.
Where's the moment?
you have moment bending on the vertical welding of the teams but not on the basic one.
instead the teams placed on the upper plate of the coupling column/brace are also subject to cutting.
Where am I wrong?

 

[@neipolos]

Isn't that the same? the normal force that you consider is caused by the bending moment (load x arm), but to me they have taught that the welding in this case can be dimensioned directly at the bending moment, i.e. sigmamax= timing divided form of bending resistance of the circular crown. In this case, having chosen as a material a s235, I will appear the sigmamax obtained with the admissible sigma of the material, multiplied by a coefficient of value 0.85. Am I wrong?

Anyway, new problem: I need to know how much power I need to rotate my arm (lifted on a circular plate bolted to the outer ring of a rotational ring with external teeth). is correct to say that j total= jcarico + jbraccio + jmotore, and consequently calculate the total torque moment with the j x epsilon formula? and consequently rise to power with formula mt x angular speed? Something sounds weird to me.. .

 

[Exatem]

Isn't that the same? the normal force that you consider is caused by the bending moment (load x arm), but to me they have taught that the welding in this case can be dimensioned directly at the bending moment, i.e. sigmamax= timing divided form of bending resistance of the circular crown. In this case, having chosen as a material a s235, I will appear the sigmamax obtained with the admissible sigma of the material, multiplied by a coefficient of value 0.85. Am I wrong?

Anyway, new problem: I need to know how much power I need to rotate my arm (lifted on a circular plate bolted to the outer ring of a rotational ring with external teeth). is correct to say that j total= jcarico + jbraccio + jmotore, and consequently calculate the total torque moment with the j x epsilon formula? and consequently rise to power with formula mt x angular speed? Something sounds weird to me.. .

But then excuse me... But if you've already solved it, I don't understand what you're looking for. . .
probably it's just a dialectic problem, they separate us a couple of generations too.
I read you're a student while I'm aiming! I haven't been a student for many years.
in my time there were no limit states, no yield was considered, newton was not yet born and went on with breaking loads and kg on mm2 (or even cm)...
the steel is called iron fe42 not s275jr and the computer was the texas calculator with the green filament display, the cell phone did not exist and turned to the maximum with two telephone tokens. . .
But the cranes have never come down, a bit like the bridges made by the Romans who are still standing after 2000 years.

 

[@neipolos]

hahaha I still appreciate the help and sympathy, but I think you became moderator of a forum, learn at least to read all the messages before responding! I had already written that the problem had been solved, then you come out with new fleas in the ear!!!!

However, please someone help me with the calculation of the power I wrote in the above message, there are also incitations like "give it to you", "stew everything"... I'm going crazy then I have to do the electrical picture and the automation part :36_1_25:

 

[Exatem]

hahaha I still appreciate the help and sympathy, but I think you became moderator of a forum, learn at least to read all the messages before responding! I had already written that the problem had been solved, then you come out with new fleas in the ear!!!!

However, please someone help me with the calculation of the power I wrote in the above message, there are also incitations like "give it to you", "stew everything"... I'm going crazy then I have to do the electrical picture and the automation part :36_1_25:

I realized that the size of the structure had solved it but I also realized that you were in trouble with the verification of the welds indeed, with the identification of the forces agents on them and as you did, you have not explained it yet.
to read I learned very soon, well before going to the elementary school and, I no longer stopped, moderator I did not "become a mò" but a few years ago and new fleas I did not find, even on my dog.
Say hi.

 

[@neipolos]

I realized that the size of the structure had solved it but I also realized that you were in trouble with the verification of the welds indeed, with the identification of the forces agents on them and as you did, you have not explained it yet.
to read I learned very soon, well before going to the elementary school and, I no longer stopped, moderator I did not "become a mò" but a few years ago and new fleas I did not find, even on my dog.
Say hi.

hahaha with age becomes permalous, yes??? don't take it from you, some mistakes also make the "old"! I'm making fun of you, but since you take it seriously, I'm gonna point out:

I rectify everything!!!! I had made a very trivial error in the calculation of the bending resistance module, in fact the circular welding held

and then again

"or better, I had to increase the thickness of the profile to 16 mm. in this way I could increase welding to 12"

So I gave the answer, you didn't read my dear moderator! peace and good

 

[meccanicamg]

Bye to all,

My name is alessandro I attend the first year of a course its mechatronics. as the first project work, witnessing the work done so far, I am designing a flag crane destined to the naval sector (precisely for the watering of boats). the starting data at my disposal, in addition to the purpose of use of the crane, are the following:
Column height: 5m
Arm length: 4m
max capacity: 2t
for the sizing of the arm I selected an ipe 360 profile, while for that of the column a circular hollow profile with external diameter 406,4mm and thickness 7,1mm.
My problem at this point is to design an arm rotation system that can be connected to an electric motor. I wondered if it could be a suitable solution to exploit the following example (see photo) by connecting the rotation pin (prolonged) through coupling to a motor fixed to the column of the crane.

alternatively I found this other example, where I think you could transmit rotation from the engine (always placed on the column) to the arm through a large toothed wheel placed in the junction.

thanks in advance for the help!

the first example is for hand rotating flag crane, while the second version is fully automated. Given the dimensions stated in departure as project data I would say that solution 2 is the most suitable one to develop.
I believe that there is already a post on the forum somewhere where we talk about these two (and certainly the second) flag cranes.
The rotation rall is a large cross roller bearing with integrated a toothed wheel controlled by pinion and gear motor. you will find "leonessa" ralles or "skf" among those where you find more explanations for the sizing of the vice and the choice of the size.

attention to the bending dimensions of the arm, bending and peak load of the tube. consider all variables, winds, oscillations, maximum load etc. then when you need to make the sizing of the hose/wind system will be a small undertaking of mechanics and safety, with brake, reducer and motor, drum. ah...this part is what was developed and there was discussion about the fact that it should be all compact and maybe there was also a section design of the group

 

[Exatem]

the first example is for flag cranes.. .

Wasted fatigue, the boy already knows everything!

... if the welding does not resist and I go then to strengthen the structure with welded tissues, for example, between column and base plate, how to calculate then the wf of the new figure I get? (in this case it will be a sun-shaped welding, a circle surrounded by rays as you can see also in the pictures above)

My boy, dear, you gave no answer.

hahaha with age becomes permalous, yes??? don't take it from you, some mistakes also make the "old"! I'm making fun of you, but since you take it seriously, I'm gonna point out:
and then again
"or better, I had to increase the thickness of the profile to 16 mm. in this way I could increase welding to 12"
So I gave the answer, you didn't read my dear moderator! peace and good

then from a tube 406,4 x 7,1 you passed to a 406,4 x16.
this not to face the problem of checking if adding eight teams would have stretched perhaps enough the useful section of welding? (for granted that the 7.1 column was sufficient).
I'm sure you've considered that a 406,4x7,1 weighs about 90 kg/m while a 406,4x16 weighs 154... yeah, but I'll tell you to. .
I think you're the one who has difficulty in understanding, and if you're young, mine who are "old" are at least justified.

p.s. I suggest you don't worry too much, even if it bothers you that it is moderator.

 

[Er Presidente]

...you passed to a 406,4 x16.

But we were talking about a flag crane or not?

p.s.: it took mel '39 certain philosophy of design, at least we could try. . .