Convert from a weighted system to a plate and bolt system

In summary, the pressure plate will not change the contact area between the bolts and the weight, but the bolt torque will need to be increased to provide the desired amount of pressure.
  • #1
plastixman
2
1
Hi all,
I need to convert a cooling fixture from a weighted system to a plate and bolt system. I'd like to use 4 - 10mm cap screws and a pressure plate to replace 7.82kg of weight. The weights are 190mm x 70mm of contact area. The pressure plate will have flanges to accommodate the bolts. But the contact area won't change.
Assuming each bolt must provide 1/4 of the pressure of the weights, each would need to provide 1.955 kg. So, T=KFd and I used 0.2 for the K constant, 10mm for the bolt dia, and 1.955kg (19.17N) for the required Force. no lubricant and I get 0.0383 Nm.

It seems to be too little torque. Would someone be nice enough to check my work?

Thanks!
Plastixman
 
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  • #2
plastixman said:
Hi all,
I need to convert a cooling fixture from a weighted system to a plate and bolt system. I'd like to use 4 - 10mm cap screws and a pressure plate to replace 7.82kg of weight. The weights are 190mm x 70mm of contact area. The pressure plate will have flanges to accommodate the bolts. But the contact area won't change.
Assuming each bolt must provide 1/4 of the pressure of the weights, each would need to provide 1.955 kg. So, T=KFd and I used 0.2 for the K constant, 10mm for the bolt dia, and 1.955kg (19.17N) for the required Force. no lubricant and I get 0.0383 Nm.

It seems to be too little torque. Would someone be nice enough to check my work?

Thanks!
Plastixman
Welcome to the PF. :smile:

Can you Upload sketches of your system before & after (or photos). Use the Upload button in the lower right of the Edit window to attach a PDF or JPEG file to your posts and replies. Thanks.
 
  • #3
Here are pictures of the bolted plate concept. I'd drill the white plate with a clearance hole and tap into the bottom plate.
The bottom pic shows the weighted system.
Thanks
 

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  • bolted plate concept.jpg
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  • weighted fixture.jpg
    weighted fixture.jpg
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  • #4
You can do an experiment to check for yourself. Carefully set the weights on your hand and note the pressure. Then put your hand under the bolted plate and tighten the bolts until you feel the same amount of squish. I suspect that you will find that your calculated value is about right.

The largest error source at low bolt torques is friction. Make sure the bolts spin in and out freely before assembling.

Suggestion: Put compression springs under the bolts and tighten to a specified height instead of trying to measure such a low torque. Bolt torque is not a good way to accurately control preload.
 
  • Informative
Likes anorlunda
  • #5
If you need uniform pressure distribution, realize that will depend on the stiffness of the white plate.
 

Related to Convert from a weighted system to a plate and bolt system

1. What is a weighted system?

A weighted system is a method of measuring and distributing weight in a structure or object. It involves using weights or counterweights to balance the load and maintain stability.

2. What is a plate and bolt system?

A plate and bolt system is a method of connecting structural components using plates and bolts. This system involves drilling holes in the components and securing them together with bolts, creating a strong and stable connection.

3. Why would someone want to convert from a weighted system to a plate and bolt system?

There are several reasons why someone may want to convert from a weighted system to a plate and bolt system. One reason may be to reduce the overall weight of the structure, making it more efficient and cost-effective. Another reason may be to increase the structural integrity and stability of the system.

4. What are the benefits of using a plate and bolt system?

Some benefits of using a plate and bolt system include increased strength and stability, reduced weight, and the ability to easily disassemble and reassemble the structure if needed. Additionally, this system allows for more precise and customizable connections, making it a popular choice in many industries.

5. What are the steps involved in converting from a weighted system to a plate and bolt system?

The steps involved in converting from a weighted system to a plate and bolt system may vary depending on the specific structure and components involved. However, some general steps may include assessing the current weight distribution and load-bearing capabilities, designing and fabricating the necessary plates and bolts, and carefully removing and replacing the weighted components with the new plate and bolt connections.

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