Custom Constant Torque Springs

Vulcan Spring specializes in manufacturing custom constant torque springs to customer specification. With Vulcan Spring’s design, engineering and manufacturing prowess, custom springs can be produced in almost the same time as stock springs. “Custom” is normal for Vulcan Spring and this has been proven to customers over and over again.

In some applications, it is desirable for the spring to change force. A spring that produces less force while being extended has a negative gradient. A spring that produces more force when extended has a positive gradient. Vulcan Spring offers both positive gradient torque springs and negative gradient torque springs.

Contorque^® constant torque springs are ideal for a wide variety of uses where constant torque / tension springs are needed, including applications requiring smooth returning and retrieving, counterbalancing applications, and tensioning and loading applications. Industries that use constant torque springs include:

• Aerospace & Defense
• Medical Devices / Healthcare
• Industrial Tools
• Window / Shade Counterbalance
• Automotive / Transportation

Materials - Type 301 stainless steel typically produces the best part at the lowest cost.

Life in total estimated number of cycles - the life of the constant torque spring is very predictable. A life cycle is an extension and retraction of either the whole spring or any portion of it.

Torque requirements - the torque of the spring should be equal to the requirement of the application.

Available space - for proper operation, leave +10% calculated according to material thickness, life, and torque required.

Minimum spool spacing calculation - the distance between spool centers (dimension "S") must be greater than the radius of the spring when fully wound on the storage spool, plus the radius of the spring when fully wound on the outpost spool.

Size - Maximum width, maximum outside diameter (O.D.), and output drum diameter

Length - Allow at least 1 1/2 turns to remain on the storage spool when the spring is fully wound, and 1 1/2 turns to remain on the output spool when the spring is unwound. The formula for determining length (L) is as follows: L = πN (Do + Nt) + 10 Do. This formula takes into account: diameter buildup, number of revolutions (N), thickness of material (t) and output spool diameter (Do).

End detail - Vulcan Spring has many standard dies to create the end detail; the image shows some that are available. Special end designs can be made for a normal charge. 

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