Freewheels and backstops

A freewheel is a one-way clutch: it transmits torque when rotation goes in one direction and disengages when it goes in the opposite direction. Depending on how it is installed, it performs three functions. As a backstop, it prevents an inclined belt, elevator or pump from reversing when stopped. As an overrunning clutch, it allows one part to rotate faster than the part driving it. As an indexer, it converts reciprocating motion into intermittent advance, for example in feeders.

Each brand names its series in its own way. In RINGSPANN, codes such as BA 100 R, BA 20 DX and BA 25 DX carry the series, a size number and a final letter for the design. In TSUBAKI, sizes such as B 203, B 205 and B 209 appear, as well as 1 M. In INA, HF0306-KF and HF0612-KF identify roller freewheels, and HF0306-KF-R is a variant of the same size. Since the suffix changes the design, the code must be requested complete.

To select, start from the torque to be transmitted or held, with a margin for starts and shocks, and the shaft diameter. Then check the maximum overrunning speed, whether the freewheel has its own bearings for centering or is mounted between the machine bearings, the method of fixing to the shaft or hub, and the lubrication. Also define the locking direction, looking at the shaft from one side and from the other.

We quote RINGSPANN, TSUBAKI and INA freewheels. Send us the complete code via WhatsApp or, if it is a replacement, the shaft diameter, rotation direction, torque and a photo of the part, and we will quote it shortly.