How Do You Calculate the Force Required to Pull Out a Pin?

[yea_right40]

Hello,

I need help calculating the (Initial and sustained) Force required to pull a round pin that is under load. I have attached a dim diagram showing the system. Please assume no friction since I haven't selected the materials. Also if you could help me calculate the Sheer force (again, I haven't selected the material) I would really appreciate it. Thanks.

 

[Studiot]

This looks like a schoolwork question.

As it stands you diagram is incomplete. Since you are neglecting friction I suppose this is a shear failure question (note the spelling of shear).

Can you add the appropriate (missing) forces to your diagram?

Also remember that your pull out force is at right angles to the loading so neither has any component in the direction of the other.

 

[yea_right40]

Hi Studiot,

Thanks for your quick response to my post. See my reply below:

>This looks like a schoolwork question.

Interesting observation. Unfortunaly it is not. This is the release system of a safety latching system I have designed. I haven't had a physics class since 1981 so I am a bit rusty.

>As it stands you diagram is incomplete. Since you are neglecting friction I suppose this is a shear failure question (note the spelling of shear).

Sorry, as I stated in my original post I haven't picked the materials so I can't calculate friction. I am looking for the formula to calculate the initial / sustained force necessary to release the pin (this is so I can select the correct strength solonoid). You are right the second part of my request was to help me with the shear calculation -this will also help me to consider which material I can select. Oh my, you did catch my typo! I won't make that mistake again. Thanks for pointing that out.

>Can you add the appropriate (missing) forces to your diagram?

I am assuming you are looking for friction. I covered that above. If you could assist me in deriving the formula I would appreciate it. If there are other forces that you believe I need please let me know.

>Also remember that your pull out force is at right angles to the loading so neither has any component in the direction of the other.

So friction is the only component to consider?

Thanks.

 

[Studiot]

From what I can see of your drawing, you have a cylindrical bolt being pulled to the left through a journal by a pullout force F that you want to calculate.

You have also shown what looks like a pin set into the bolt on the other side of the journal from F, although this is not shown as such in the section (elevation?) to the right.
Presumably this pin bears against the back of the journal and prevent the bolt withdrawing, so what you need is the force to break (shear) it across.

Without such a pin there is nothing to hold the bolt in place, in the absence of friction.

Can you confirm that I am reading your arrangement correctly?

There is further comment worth making: applying nearly 2 tons of force as shown will certainly tend to rotate the bolt so that it jams in the journal, rather than slides.

 

[alphy]

Hello there,

I understand the importance of accurately calculating forces in any system. In order to calculate the pin pull out force, we need to consider several factors such as the material properties of the pin and the surrounding materials, the geometry of the pin and its fit within the system, and the applied load on the pin.

To start, we can use the formula F = μN, where F is the force required to pull the pin, μ is the coefficient of friction between the pin and the surrounding materials, and N is the normal force acting on the pin. Without knowing the specific materials being used, we cannot accurately determine the coefficient of friction. However, we can assume a value based on common materials and then adjust it once the materials are selected.

Next, we need to consider the geometry of the pin and its fit within the system. The tighter the fit, the higher the initial force required to pull the pin. This can be calculated using the formula F = kμN, where k is a constant that takes into account the geometry and fit of the pin.

In order to calculate the sheer force, we need to know the material properties of both the pin and the surrounding materials. Sheer force is the force required to cut or break the pin, and it is dependent on the strength and hardness of the materials involved. Once the materials are selected, we can use their respective shear strength values to calculate the sheer force using the formula F = Aσ, where A is the area of the pin and σ is the shear strength of the material.

I hope this information helps you in your calculations. Please keep in mind that these are general formulas and may need to be adjusted once the specific materials are chosen. It is always best to consult with a materials engineer for more accurate and precise calculations. Best of luck with your project.