Will my steel ejection mold bolts shear under sideways load?

In summary, the design of the bridge on an ejection mold may cause bolts to shear due to sideways load. Mechanical Engineers may need to design a solution to prevent this from happening.
  • #1
jessemk
1
0
hello.
I have a ejection mold (steel) which has a bridge like mount which locates the handling eye bolts outward around hydraulic cylinders. I need to make sure the bolts in the bridge will not shear due to the sideways load when the mold is lifted or flipped 90degrees. Here is the known information:
mold weight: 5,900 lbs
Bolt Dia: 5/8"
Bolt total length: 10.5"
Bolt thread engagement: 1.125"
Number of bolts in bridge 4

Color representation:
blue:Injection mold
orange: cylindrical steel pillars with a clearance hole through
purple: eye bolt mounting plate
Red:Bolt-socket head cap screw
upload_2015-9-18_12-20-18.png
 

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  • #2
jessemk said:
hello.
I have a ejection mold (steel) which has a bridge like mount which locates the handling eye bolts outward around hydraulic cylinders. I need to make sure the bolts in the bridge will not shear due to the sideways load when the mold is lifted or flipped 90degrees. Here is the known information:
mold weight: 5,900 lbs
Bolt Dia: 5/8"
Bolt total length: 10.5"
Bolt thread engagement: 1.125"
Number of bolts in bridge 4

Color representation:
blue:Injection mold
orange: cylindrical steel pillars with a clearance hole through
purple: eye bolt mounting plate
Red:Bolt-socket head cap screw
View attachment 88827

Welcome to the PF.

What is your mechanical design background?
 
  • #3
There is a very real safety issue with this design.
Because the cylindrical steel pillars are independent of each other they will greatly multiply the bolt tension at the start of the lift.
That multiplication factor will be something like their length divided by the difference between the pillar radius and the bolt hole radius. Factor = Lengthpillar * ( Rpillar - Rhole )

To eliminate the problem, a competent Mechanical Engineer, (with an insurance policy), would need to review the situation and possibly design something like a diagonal brace or a plate to unify the pillars.
 
  • #4
Thank you, Baluncore.

And with that advice, this thread is closed.
 

1. What is bolt shear and why is it important?

Bolt shear is the force that causes a bolt to fail when loaded perpendicular to its axis. It is important to consider in structural designs because if a bolt fails, it can compromise the integrity and safety of the structure.

2. How is bolt shear calculated?

Bolt shear can be calculated using the formula F = P x A, where F is the force in pounds, P is the pressure in pounds per square inch, and A is the cross-sectional area of the bolt in square inches.

3. What factors affect bolt shear strength?

There are several factors that can affect bolt shear strength, including the type and grade of the bolt, the material it is being used on, and the size and length of the bolt. Additionally, the method of installation and the presence of any external forces can also impact the bolt shear strength.

4. How do bolt shear calculations differ for different types of bolts?

The calculations for bolt shear can vary depending on the type of bolt being used. For example, a carriage bolt may have a different shear strength than a hex bolt due to their different shapes and sizes. It is important to refer to the manufacturer's specifications for each specific type of bolt being used.

5. How can I ensure accurate bolt shear calculations?

To ensure accurate bolt shear calculations, it is important to follow the proper installation procedures and use the correct measurements for the bolt being used. It is also important to consider any external factors, such as wind or seismic loads, that may affect the bolt's shear strength. Additionally, seeking the guidance of a professional engineer can help ensure accurate calculations for structural designs.

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