How Slip Clutches Work
All Polyclutch® slip clutches perform the basic function of controlling the torque between two elements. They can be supplied as a shaft-to-shaft coupling or a shaft to pulley, gear, or sprocket model. Polyclutch custom slip clutches can be provided with nonstandard bore sizes, keyways, low backlash or higher torque, minus housings and with pulley, gear or sprocket. Imagination and ingenuity have developed and created additional variations.
A Polyclutch consists of two parts: a cartridge and a housing (see diagram)
The cartridge is set screwed or keyed to the input shaft. The cartridge includes the clutch pack: outer plates, friction pads, inner plates
- Plates are brass with a proprietary finish
- Inner plates are keyed to the cartridge hub
- Outer plates are keyed to the cartridge housing
- Friction pads are a proprietary plastic-based composite (no asbestos)
The housing is either set screwed or keyed to the output shaft, or (as shown), attached to the output gear or pulley, with a bronze bearing to allow relative motion between the input shaft and the output gear/pulley.
Torque is controlled by changing the pressure applied to the clutch pack. In an adjustable style clutch, the torque level is controlled by compressing the springs with the adjusting nut. In a fixed style clutch, a collar is attached to the hub in a fixed position, and the torque level is set by pushing and locking the spring collar to a calibrated position.
Tolerances, Backlash & Break-In
All slip clutch torques are calibrated to +/- 20% but can be held to closer tolerances. Please discuss your requirements with Dynatect engineering.
Backlash of 6° is standard for Slipper models and 2° for the Slip-Ease models. Slipper models can be held to 2° if required.
Our proprietary burn-in process insures that all clutches will perform consistently right out of the box, with no break-in period required.