Torsion springs are helical springs that exert a torque or rotary force and are subject to bending stresses. Torsion springs should always wind up from the free position – never to unwind from the free position. As they wind up, torsion springs reduce in diameter and their length becomes longer. Such springs should be supported over a rod whenever possible. Some spacing should remain between coils to minimize friction which can alter torque and deflection.
There are an infinite number of torsion end configurations. The most economic end type is the straight torsion end. Other types of popular torsion ends include hook, hinged and straight offset. For more detailed information regarding types of torsion ends contact Katy Spring.
To define, torque is a force that produces rotation. Torsion springs exert force in a circular arc in which the arms rotate about a central axis. The stress is in bending. In the spring industry it is customary to specify torque with deflection or with the arms at a definite position. Formulas for torque are in inch pounds. When a force is specified at a distance from the centerline, the torque, is called the moment, is equal to the force multiplied by the distance.
Several methods for designing torsion springs can be used. The easiest would be to contact Katy Spring with parameters including; force needed, space limitations, shaft size, maximum body length allowed, environment the spring is used in, and number of deflections. These can be calculated manually but are done much easier with spring design software.