It is well known that many mechanical devices operate on a power transfer from one rotating member to another. It is common to connect an input power source to an output driven member by means of a torque limiter of sorts. Indeed, the utilization of torque limiting clutches between input and output members is now a common expedient to prevent damage and unnecessary down time.
It is well known that torque limiting clutches can be assembled to provide a large variety of characteristic break-away torques. Further, the physical size of torque limiting clutches often correlates with the system to be protected and the characteristic torque load. It is well known to those skilled in the art that it is most difficult to design and construct torque limiting clutches which are physically small in size. As the physical size of the torque limiting clutch decreases, the ability to hold close tolerances to maintain fixed and predictable break-away torques decreases. In prior art torque limiting clutches it has also been difficult to verify the torque setting. Additionally, such torque limiting clutches are difficult to assemble, demonstrate high output inertia, are typically characterized by significant changes in the break-away torque over the wear life of the clutch, are given to tampering and/or field adjustments, and are generally incapable of providing means for indicating the state of wear thereof.
While many machines and other devices have need of torque limiting clutches which are physically small in size, no small friction type units are available which are truly effective and reliable in operation.