Need some help with cantilevered assembly.

[pityocamptes]

Hopefully someone here can help me. My schooling is in computer engineering, and so I lack knowledge in mech eng. Anyway, I am helping a friend build a small hoist on his ranch that will be used for processing pigs and other medium to semi large animals. The tubing is square, structural grade tube, and is 2x2x.125

The assembly is 82 inches high with the top cross beam being 36 inches long (the bottom will have small gussets to add strength to the base). In the middle of this top cross beam will be a pulley that has a winch cable going through it. The winch will drag the animal a short distance and eventually pull it up so that the animal is suspended under the top beam for processing.

I would appreciate any help to try and figure out what the failure load for the assembly would be, especially the 82 inch side pieces. I would also be interested in load and deflection data. I assume a safety rating of .55 the maximum load would be standard?

Can anyone post the formulas that would be used to compute the information I desire? Perhaps someone would also be kind enough to help me out if I post back with questions. I appreciate any help offered. Thanks!


-Now that I really think of it since the top beam has a pulley, won't most of the horizontal load (when dragging animal short distance) be transferred to the winch mounting base? I assume a small load will be applied to the vertical pillars through cable friction on the pulley. Then once the load has been hauled up and suspended under the top beam the load would transfer to the center of the 36" top beam, correct? Thoughts appreciated. Thanks again!

Picture attached.

 

[Aaron Bex]

Yes, the load would be transferred to the pulley and then the winch mounting base. The vertical pillars will have some load applied due to cable friction on the pulley, but the majority of the load will be transferred to the winch mounting base.

To calculate the failure load for the assembly, you will need to know the material properties of the structural grade tube you are using (e.g. yield strength, modulus of elasticity, etc.). You can then use these material properties along with the dimensions of the assembly to compute the maximum load the assembly can support before it fails (e.g. using beam theory or other structural analysis methods). Additionally, you can also calculate the deflection of the assembly under a given load using the same material properties and dimensions.

 

[ravenprp]

Hello,

I am not a mechanical engineer, but I can offer some general advice on your cantilevered assembly. First, it is important to understand the load that will be placed on the assembly. In this case, it will be the weight of the animal being lifted, as well as any additional force from the winch pulling on the cable. It is also important to consider any potential side-to-side movement of the animal during processing, which could add additional stress on the assembly.

To calculate the failure load, you will need to determine the maximum weight that the assembly can safely support without breaking or bending. This will depend on the strength and structural integrity of the materials being used, as well as the design and construction of the assembly. It is always a good idea to plan for a safety factor, so using a safety rating of 0.55 as mentioned in your post is a good starting point.

In terms of formulas, there are several that can be used to calculate the failure load and deflection of a cantilevered assembly. One common formula is the Euler-Bernoulli equation, which relates the applied load, material properties, and geometry of the assembly to the deflection and bending stress. There are also online calculators and software programs available that can help with these calculations.

Regarding your question about the load being transferred to the winch mounting base, it is likely that most of the horizontal load will be transferred to the base, but there will still be some load on the vertical pillars through the cable friction on the pulley. Once the animal is suspended under the top beam, the load will be primarily on the center of the beam, but it is important to ensure that the entire assembly is designed to support this weight.

I hope this helps to provide some guidance on your cantilevered assembly. It is always best to consult with a mechanical engineer or other qualified professional for specific calculations and design recommendations. Good luck with your project!