Solving Torsion Spring Problem with 100 lb Force

• bpaliwal
In summary: In your case, since there is only a single force and angle of rotation, the spring rate is not a factor.
bpaliwal
I am struggling through a problem in one of my designs and would appreciate some help.
Please refer to the image attached.

Problem Description:
S = Torsion spring
F = fixed point
T = tire

A tire is attached to a torsion spring through an arm as shown in the image. The torsion spring has one end connected to a fixed wall and the other connected to the arm S-T at point F.
How much spring rate (lbs-in/degree) should be there on the spring S, so that the tire T is subjected to a force of 100lbs in the downward direction before any deflection occurs in the spring?

Also, I forgot to mention in the image the angle of S-T with the horizontal is 33.127 degrees.

Any help would be appreciated.

If you want the tire to be able to be subject to 100lb of force before there is any deflection, you need the mechanism to be against an end stop and the spring subject to pretension. If you don't have an end stop and a pre-tensioned spring, there is no spring rate you can chose to achieve this - no matter what the rate is, you will always see some deflection at any force level.

bpaliwal
cjl said:
If you want the tire to be able to be subject to 100lb of force before there is any deflection, you need the mechanism to be against an end stop and the spring subject to pretension. If you don't have an end stop and a pre-tensioned spring, there is no spring rate you can chose to achieve this - no matter what the rate is, you will always see some deflection at any force level.
Thanks for the response.
I am working on the pretension design for the spring. All I am concerned about is how much spring rate do I need?
Considering everything is weightless, will it be just the 100lbs force multiplied by the horizontal distance between the tire and the spring center? Regards

For what you have shown you would be calculating the required torque of the spring. Once you have that value, then it is just a matter of going to catalogs to find an appropriate spring that will supply that torque.
Spring rate for an application is only a factor when there two required forces and required angle of rotation for the spring between those two forces.

1. How do you calculate the torque of a torsion spring with a 100 lb force?

The torque of a torsion spring can be calculated using the formula T = kθ, where T is the torque, k is the spring constant, and θ is the angle of rotation. To find the spring constant, divide the force by the distance from the center of the spring to the point where the force is applied.

2. What is the maximum weight a torsion spring can support with a 100 lb force?

The maximum weight that a torsion spring can support with a 100 lb force depends on the spring's dimensions and material. The spring constant and maximum angle of rotation can also affect the weight that the spring can support. It is best to consult a spring manufacturer or perform a stress analysis to determine the maximum weight a torsion spring can support.

3. How do you determine the angle of rotation for a torsion spring with a 100 lb force?

The angle of rotation for a torsion spring can be determined by dividing the torque by the spring constant. This will give you the maximum angle of rotation that the spring can handle before reaching its elastic limit.

4. Can a torsion spring with a 100 lb force be used for heavy-duty applications?

The weight capacity of a torsion spring with a 100 lb force can vary depending on its dimensions and material. It is possible for a torsion spring with a 100 lb force to be used for heavy-duty applications, but it is important to consult a spring manufacturer or perform a stress analysis to ensure that the spring can handle the required weight and torque.

5. How do you ensure the safety of using a torsion spring with a 100 lb force?

To ensure the safety of using a torsion spring with a 100 lb force, it is important to choose the appropriate spring for the application and to follow proper installation and maintenance procedures. It is also crucial to regularly inspect the spring for any signs of wear or damage and to replace it if necessary. Consulting a spring manufacturer or engineer can also help ensure the safety of using a torsion spring in any application.

Replies
4
Views
1K
Replies
14
Views
782
Replies
1
Views
5K
Replies
6
Views
1K
Replies
3
Views
2K
Replies
5
Views
3K
Replies
2
Views
1K
Replies
52
Views
2K
Replies
6
Views
8K
Replies
52
Views
11K