Manufacturer of Custom Torsion Springs
Torsion springs are helical springs that exert a torque or rotary force and are subject to bending stresses. There are an infinite number of torsion end configurations.
• Straight torsion end (the most economical type)
• Straight offset
Ordering Torsion Springs
Katy Spring can assist customers in determining the torque required by a torsion spring.
- A spring index (inside diameter divided by wire diameter) between 4 and 14 is best, because larger ratios require more tolerance and are more expensive and difficult to manufacture. Ratios under 3 do not give accurate results determined by design formulas and cannot often be coiled on automatic machines.
- Torsion springs under 3 coils usually buckle and often do not produce accurate test results. 30 or more coils may cause only some coils not to deflect, especially under light loads with a supporting rod.
- Specify number of coils to the nearest fraction; i.e. 5 ¼.
- If torsion springs are not supported by a rod running through the center, they may buckle and are subjected to additional stresses.
- The inside diameter of a torsion spring reduces during deflection. Allowance should be made for clearance in addition to the normal spring tolerances.
- Torsion springs should have some space and no initial tension between the coils. If a torsion spring is wound tightly, they may not deflect uniformly or test accurately. A slight space of 20-25 percent of the wire size is desirable. Square and rectangular wire should be avoided as they are expensive and often hard to find.
- The hand or direction should be specified when ordering torsion springs. As a torsion spring winds up it has more coils. The increase in coils and in overall length should be allowed for during design. Deflecting a torsion spring in the “unwind direction” causes high stresses and can cause early failure. A spring wound clockwise is a “left hand” wound spring.
- Arms of a torsion spring can be calculated as active coils in some cases. Deflection of long extended arms cab be calculated by allowing one third of the arm length, from the point of force contact to the body of the spring, converted into coils. If the length of arm is equal or less than half the length of one coil, it can be safely neglected in most applications.
- Bends in arms of torsion springs can be expensive and should be avoided whenever possible. Bend radii should be as large as possible to reduce stresses.
- Double body torsion springs are used as a left hand torsion spring and a right hand torsion spring connected at the center. They can be expensive and it is better to use 2 torsion springs (1 right and 1 left) whenever possible.
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Read a blog post about torsion springs here.