Freewheels Backstops • Overrunning Clutches • Indexing Freewheels Edition 2026/2027 RINGSPANN® Registered trademark of RINGSPANN GmbH, Bad Hombu

The maximum transmissible torques are 2 times the specified nominal torques. Issue 12/2025 • Technical details subject to change without notice.

Design and Function of Freewheels Freewheels are machine elements with particular characteristics: • In one direction of rotation there is no contact between the inner and outer ring; the freewheel is in freewheeling operation. • In the other direction of rotation there is contact between the inner and outer ring; in this direction it is possible to transmit high torque. For example the outer ring of the freewheel shown in figure 4-1 can freewheel clockwise while the inner ring is stationary. If, however, the outer ring is turned in the opposite direction, there is contact between the inner and...

➧ Backstop Freewheels are used as backstops if reverse rotation of the operating direction is to be prevented. In many machines and installations, for technical safety or functional reasons, it is necessary to ensure that you are working in just one specified direction of rotation. This is why there are legal stipulations requiring a mechanical safety device for the operation of, e.g. conveyor systems. The normal operating mode of a backstop is freewheeling operation; the locking (torque transmission) is performed at zero speed. The immediate engagement of the clamping elements ensures the required...

Areas of Application for Freewheels ➧ Areas of application for Backstops Gear units Electric motors Gear motors Inclined conveyors Elevators Bucket elevators The backstop prevents reverse rotation in a drive of a conveyor installation if the power fails or the motor is turned off. The backstop prevents reverse rotation of the conveyor load if the power fails or the motor is turned off. ➧ Areas of application for Overrunning Clutches Textile machines Printing machines Fans Ventilators During normal operation of textile or printing machines, the overrunning clutch separates the barring drive which...

The backstop prevents reverse rotation under the back pressure of The backstop prevents reverse rotation under the back pressure of the conveyed medium if the motor is turned off. the conveyed medium if the motor is turned off. Pumps Roller conveyor In multi-motor drives the overrunning clutch disengages the inactive or lower speed drive. The overrunning clutch ensures that the conveyed material can be pushed or pulled faster over the rollers than the speed of the drive. Seed spreader High voltage switches The indexing freewheel replaces a reduction gear in seed spreader. In high voltage switches...

• With bearing support between inner or outer ring • Completely enclosed • Connection to the outer ring and the customer part by: - bolting to the face (figure 8-1), - mounting flange, - keyway connection on the outer ring, - shaft coupling. • With bearing support from inner to outer ring • Completely enclosed • With bearing support between inner and outer ring • Completely enclosed by its own housing • With bearing supported input and output shafts • Stationary arrangement

RINGSPANN*Basic Freewheels • With bearing support between inner and outer ring • For assembly with connecting parts • Lubrication - if necessary - to be provided by the customer • Without bearing support. Concentric alignment of inner and outer ring must be provided by the customer. • Integrating the outer ring on the customer part by bolting to the face • Lubrication - if necessary - to be provided by the customer • Series both with and without bearing support. In the case of series without bearing support, concentric alignment of the inner and outer ring must be provided by the customer. •...

Freewheels with Sprags or Rollers two different designs of freewheels Design as Sprag Freewheel The sprag freewheel has outer and inner rings with cylindrical tracks. The individually spring loaded sprags are arranged in between the rings. The freewheel locks without slipping. Different sprag profiles enable a multitude of types. Types are available for: • High torques • Contactless freewheeling operation • High indexing accuracy 10-1 Function of Sprag Freewheels With the sprag arrangement illustrated in figure 10-2 the outer ring can be turned freely clockwise (freewheeling operation), if the...

Design as a Roller Freewheel With roller freewheels either the inner or the outer ring has roller ramps. The other ring has a cylindrical track. The individually spring loaded rollers are arranged in between the rings. The freewheel locks without slipping. Function of Roller Freewheels Locking direction or driving operation With the version illustrated in figure 11-2, the outer ring can be turned freely clockwise (freewheeling operation), if the inner ring Freewheeling direction or freewheeling operation • is at a standstill, • is turned counter-clockwise or Spring force Outer track • is turned...

In addition the standard type, RINGSPANN has vice life for freewheels with sprags. The table ditions for these types. developed four other types for extended ser- above lists the recommended application con- Type with sprag lift-off X The sprag lift-off X is used for backstops and overrunning clutches, provided that in freewheeling operation the inner ring is rotating at high speed and providing with overrunning clutches that the driving operation is conducted at low speed. In freewheeling operation, the centrifugal force Fc causes the sprag to lift off from the outer track. In this operating...

Type RIDUVIT® RINGSPANN sprags are made from chrome steel, the same material as used for the balls in ball bearings. The high compressive strength, elasticity and tensile strength of this material is required for the sprags in a locked state. In freewheeling operation, however, it is able to cope with utmost wear resistance on the points of contact of the sprag with the inner track. All of these requirements are perfectly fulfilled by using a chrome steel sprag with RIDUVIT® coating. The RIDUVIT® coating lends the sprag a resistance to wear akin to that of hard metal. The technology used here...