Given force, need to determine what bearing to use for a crane

AI Thread Summary
To determine the appropriate bearings for a manual crane capable of lifting 1000 kg, the discussion focuses on calculating the radial force (P) and the dynamic load capacity (C) needed for the bearings. The radial force is estimated at 10 kN, and participants suggest using a Free Body Diagram to analyze forces, including potential axial loads. There is a debate about the correct calculations for bearing life and load capacity, with some participants noting discrepancies in the results obtained. Additionally, considerations for the baseplate and bolt specifications are discussed, emphasizing the importance of understanding the load distribution and the role of the boom in the crane's mechanics. Overall, accurate calculations and a clear understanding of the forces involved are crucial for selecting the right components for the crane.
  • #51
salamikorv said:
the forces he got is correct as our supervisors has checked them for us
What supervisors? Is this for a schoolwork project? Or are you tasked with doing this in real life at work?
 
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  • #52
berkeman said:
What supervisors? Is this for a schoolwork project? Or are you tasked with doing this in real life at work?
I'm sensing this is a school project.
 
  • #53
berkeman said:
What supervisors? Is this for a schoolwork project? Or are you tasked with doing this in real life at work?
Yea its a school project, no its not for real life work. We get help from the studentassistents in the lectures all the time. They give us direct methods that we can use to make our parts, thats how i determined the bearings because its thanks to them. But ive been sick this week, still i am, so i havent been able to go to school and ask for help and its been difficult to understand how i can get the tension for the bolts when i have two forces directed in two different directions.
 
  • #54
Okay, thanks for the info. I'll move your thread to the schoolwork forums then. You will still get the same good help there.
 
  • #55
berkeman said:
Okay, thanks for the info. I'll move your thread to the schoolwork forums then. You will still get the same good help there.
Oh alright. @erobz can you still help?
 
  • #56
1682180509966.png


Maybe I'm missing something or inferring too much about dimensions. Lets try a sanity check to see if that is indeed the loading on your base. Apply the loads your supervisors tell you are correct. Is the beam in equilibrium?
 
  • #57
erobz said:
View attachment 325318

Maybe I'm missing something or inferring too much about dimensions. Lets try a sanity check to see if that is indeed the loading on your base. Apply the loads your supervisors tell you are correct. Is the beam in equilibrium?
Yes it is.
 
  • #58
salamikorv said:
Yes it is.
what are the missing dimensions?
 
  • #59
erobz said:
what are the missing dimensions?
1.5m to the left, i mean thats the length from the left end of the beam to the point where you drew the upward force, and 0.75m is the length thats left
 
  • #60
salamikorv said:
1.5m to the left and 0.75m to the right
Explain how its in static equilibrium with an unbalanced horizontal force component from the support and the tension on the pulley?
 
  • #61
erobz said:
Explain how its in static equilibrium with an unbalanced horizontal force component from the support and the tension on the pulley?
The beams are in static equilibrium since they are in rest state but yeah i guess with the pulleys its not in equilibrium once it starts to lift, when we stop the winch then its in static equilibrium.
 
  • #62
What do you mean by an "unbalanced horizontal force"? Why cant you just assume the forces is right i dont really get this.
 
  • #63
salamikorv said:
What do you mean by an "unbalanced horizontal force"?
The forces in the horizontal direction are unbalanced. The beam is not in static equilibrium with the loading your supervisors told you was correct.
salamikorv said:
Why cant you just assume the forces is right i dont really get this.
?? Do you wan't to find the actual loading on your mounting bracket?
 
  • #64
erobz said:
The forces in the horizontal direction are unbalanced. The beam is not in static equilibrium with the loading your supervisors told you was correct.

?? Do you wan't to find the actual loading on your mounting bracket?
Im fine with the forces i have and what the studentassistant has told us, no offense by the way. I dont want to say my mates calculations are wrong since he has got alot of help from the assistants , if i asked for help of an exercise in my book with these information given would you just ignore the information given and find it yourself? (poorly explained but i think you understand what im saying here). Just assume its 30kN directed as i drew it and 20kN on the side like i drew it, its alright. All i wanna understand is how to determine the bolts.
 
  • #65
salamikorv said:
Im fine with the forces i have and what the studentassistant has told us, no offense by the way. I dont want to say my mates calculations are wrong since he has got alot of help from the assistants , if i asked for help of an exercise in my book with these information given would you just ignore the information given and find it yourself? (poorly explained but i think you understand what im saying here). Just assume its 30kN directed as i drew it and 20kN on the side like i drew it, its alright. All i wanna understand is how to determine the bolts.
Sizing the bolts requires having as close to an accurate loading as reasonably possible. If you don't care about having accurate loads, then why do you care about sizing the bolts accurately?

Imagine for a moment you are an engineer and you are designing a bridge that your family will travel everyday, and many others families will travel... And you say, but I don't care about the loads being accurate, I just care about sizing these bolts that hold the bridge up...SMH.

Maybe I'm wrong. I'll just gracefully bow out and let someone else help you.
 
  • #66
erobz said:
Sizing the bolts requires having as close to an accurate loading as reasonably possible. If you don't care about having accurate loads, then why do you care about sizing the bolts accurately?

Imagine for a moment you are an engineer and you are designing a bridge that your family will travel everyday, and many others families will travel... And you say, but I don't care about the loads being accurate, I just care about sizing these bolts that hold the bridge up...SMH.

Maybe I'm wrong. I'll just gracefully bow out and let someone else help you.
Hhahaha yeah but im pretty confident he hasnt done any mistakes. Look, i can discuss this with him later on but i came here to get help from the problems i got, and that is to determine the bolts. If you re-did the calculations and got something else thats fine, but im only for understanding how to get the bolts. I dont get why you are so passionate about re-doing it, theres plenty of cranes with those exact loads he got, why cant you just help me understand how to get dimension the bolts, not even the loading but the general steps as in the formulas like Baluncore showed, i didnt give him numbers but he showed one way of determing the bolts. Let the force thats in compression be called K, no number, and the other force Q, so i got two loads. What principle/method do i have to use in order to determine the bolts?
We dont have much time, im not going to use an hour to re-do his calculations in order for you to just show the method of determining bolts in a crane situation like this. Just having this conversation has been taking way more than an hour.
 
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  • #67
I have this crane that has to be able to lift a weight of maximum 1000kg. Its a type of a manual winch crane thats going to be able to rotate. I need help with the rotating part, i want to determine the bearings inside this rotating part and im thinking to use 2 bearings in there but im not sure if you can use welding on the edge of the bearings and make it stuck? And how i should determine them.
Image (22).jpeg
 
  • #68
@erobz alright fine, we can re-do it then.
 
  • #69
The bearing system will need to support both axial and radial loads. Why do you have four different bearing surfaces? Why are the two "bearings" so close together? What experience do you have in objects that weigh a ton? Perhaps you can work with someone locally.

es
 
  • #70
I backed out at post #40, after the base went from square to round, without rational discussion. I now know this is a poorly organised school exercise, we were dealing with a hidden committee, while communicating through a bottleneck. It is still my opinion that, without clear labelled drawings, discussion is a waste of time.
 
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