Friction is the force that opposes the relative motion or tendency toward such motion of two surfaces in contact. It is not a fundamental force, as it is made up of electromagnetic forces between atoms. When contacting surfaces move relative to each other, the friction between the two objects converts kinetic energy into thermal energy, or heat.
The mathematical theory behind the Spring Clutch was developed by C.F Wiebusch in 1939. Although he analyzed the action between two cylinders placed end to end, rotating on a common axis and torsionally coupled by the friction between the cylinders and a coil spring fitted over the cylinders, the same analysis can be applied to the wrap-around spring band technology.
The original clutches can be found in the old telephone-dial. Such mechanisms allow the dial to be wound up without dragging the governor and to couple the governor to the systems with a negligible backlash for motion in the pulsing direction.
Clearly if the driving drum be rotated in the direction to wind up the spring and decrease the diameter, the spring will grip the cylinders and be capable of exerting more torque than it would in the direction of rotation which to unwind the spring.
C.F Wiebusch developed the equations which permit the calculations of these two torque values in terms of the physical dimensions and the material constants when no torque is applied.
Hanaya adopted the wrap spring clutch over the other technologies because of its reliability in terms of consistency of torque over the life of the hinge and its durability.
When designing you device, use the following list of features to better find a suitable hinge for your application:
• Torque Requirement: Not only should you use our torque calculator but also feel free to contact Hanaya Inc for free samples.
• Footprint: The smaller the envelop, the more flexibility in the design. Hanaya’s engineering department can help you find the appropriate model or can design a custom hinge at no cost.
• Life Requirement: Determine the expected life of your application in terms of the number of cycles you expect the hinge to be opened and closed over the life of the product.
• Consistent Torque Over Life: This is a key for reliable performance of the hinge over the life of the product. Quality hinges will meet your torque specifications over the entire life of your application.
• Dynamic and Static Torque: Both should be as close in value as possible. Hanaya offers the closest ratio of all the competitors, almost 1 to1. This will keep the spring back to a minimum.
• Free Play: A precision manufacturing will eliminate free play.
• Environmental: Hanaya friction hinges are RoHS compliant
