Although torsional springs torque instead of deflecting in a linear manner (like compression and extension springs) they still have a rate of inch-pounds per degree.
Now, in order to make the subject easier to digest, let’s compare it to something we are all more familiar with:
YOUR HOURLY RATE.
If your hourly rate is $50 dollars an hour and you work 8 hours, you’ve earned yourself $400.
You multiply your rate by the amount of hours worked (traveled) to know how much you earn each day, week, month, etc.
Therefore, if your spring rate is 50 pounds, and your spring compresses (travels) 8 inches, you have applied a load of 400 pounds.
Your hourly rate is in dollars per hour, while spring rate is pounds per inch.
If you look at how both are expressed, you’ll notice the fraction disguised in the units of measurement.
Your hourly rate is expressed like this:
dollars per hour
$ / hr
Your spring rate is expressed like this:
pounds per inch
lbs / in
To turn a fraction into a decimal or whole number, you divide the numerator by the denominator. This is exactly how you calculate your spring’s rate!
Plug in your working loads into the units of measurement of your fraction. Let’s say you are placing 80 pounds on your spring, and expect it to compress 2.5 inches under that load. Thats is 80 pounds per 2.5 inches. Now, we put the 80 pounds as the numerator, the 2.5 inches as the denominator, and divide!
80 pounds PER 2.5 inches80 / 2.5 = 32
If the above didn’t help, you have several diagrams available to explain it better. After all, a picture is worth a thousand words!
Below are a few other articles from Acxess Spring that can help you understand and calculate spring rate. If you need further assistance, you can also count on our experienced spring engineers to help you with the calculation or creation of your spring design.
- Compression Spring Rate
- Linear Spring Rate
- Meaning of Spring Rate
- Spring Load and Spring Rate
- Torsion Spring Rate
If there are other subjects related to springs that you would like to read about here, feel free to send me an email at firstname.lastname@example.org.