grantmech
Mechanical
- Aug 21, 2024
- 1
Hello!
I am designing a fall restraint system for one of my vibe tables and I would like to incorporate the existing geometry into my design. Specifically I am looking at using the the M56 threaded lifting points (2 per side) as thru holes for 2'' 4-1/2 UNC bolts which thread into custom mounts into which a 2'' x 2'' support post seats, retained in the mount by a quick release pin. The posts have thru holes which allows for a connecting rod to slide in/out via a quick-release pin on one end. I have attached a diagram below with more detail.
The only requirement for the system is that it "must withstand an ultimate load of 3000 lbs. applied horizontally in any direction". I have already analyzed the reactions of the custom mounts, support posts, and connecting rod. The vibe table lifting points are located on 5'' thick steel plate and all the other components are 4140 steel so the joint would be stiff.
My question is regarding the 2'' bolts - I am not sure how analyze these joints, specifically the substantial out of plane bending (~ 93,000 in-lbs.) that will be transferred to the bolts. I searched through Shigley's but couldn't find any information about a bolted joint loaded in this particular configuration. I understand that subjecting bolts to bending should be avoided but I am wondering if there is an accepted method that can be used to analyze a case like this? Specifically I would like to know:
1. How much much preload is required?
2. Is 2'' of thread engagement in the mount (purple part in diagram) sufficient?
Any guidance would be appreciated, thanks!
I am designing a fall restraint system for one of my vibe tables and I would like to incorporate the existing geometry into my design. Specifically I am looking at using the the M56 threaded lifting points (2 per side) as thru holes for 2'' 4-1/2 UNC bolts which thread into custom mounts into which a 2'' x 2'' support post seats, retained in the mount by a quick release pin. The posts have thru holes which allows for a connecting rod to slide in/out via a quick-release pin on one end. I have attached a diagram below with more detail.
The only requirement for the system is that it "must withstand an ultimate load of 3000 lbs. applied horizontally in any direction". I have already analyzed the reactions of the custom mounts, support posts, and connecting rod. The vibe table lifting points are located on 5'' thick steel plate and all the other components are 4140 steel so the joint would be stiff.
My question is regarding the 2'' bolts - I am not sure how analyze these joints, specifically the substantial out of plane bending (~ 93,000 in-lbs.) that will be transferred to the bolts. I searched through Shigley's but couldn't find any information about a bolted joint loaded in this particular configuration. I understand that subjecting bolts to bending should be avoided but I am wondering if there is an accepted method that can be used to analyze a case like this? Specifically I would like to know:
1. How much much preload is required?
2. Is 2'' of thread engagement in the mount (purple part in diagram) sufficient?
Any guidance would be appreciated, thanks!
