Freewheel Clutches - Cross & Morse - #2

Freewheels are precision clutches which positively lock to transmit torque in one direction of rotation, but are totally released in the opposite direction, as in the sketches alongside of a roller-ramp system. Original types of freewheels (also referred to as One­Way clutches) were based on the ratchet and pawl principle, of which the Cross IRF clutches are a direct

development, and these often provide the simplest and lowest cost solutions for many applications. Modern demands of high speeds, quiet operation, and high accuracy of control have led to the development of an extensive range of sprag, roller ramp, and contact-free

element clutches, to provide the designer with a wide selection of options for uni­directional drive. Freewheels are used for three basic functions of transmission; overrunning, indexing and backstopping.

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In this mode reciprocating motion applied to the driving race of the clutch is transformed into uni­directional intermittent motion of the driven race. This function is typically used for indexing of conveyors, packaging materials and sheet steel in presses. The intermittent movement can also be used as a means of obtaining slow rotational speeds for products such as inking rollers.

The object of backstop clutches is to prevent reverse rotation of the drive shafts, which otherwise would cause damage to the machinery. Backstopping is achieved simply by anchoring one race of the clutch so that the other race is free to rotate in one direction, but is immediately locked in reverse. These are typically used on conveyors, elevators, cranes and pumps.

In this mode of operation the output can rotate faster than the input or continue to rotate if the input is

stopped. Should the input drive be reversed there will be no drive to the output. This is typically used in starter drives for engines or turbines to provide automatic decoupling of starter motor drive when operational speed is reached; on bi-motor drives; and also to overcome the problems of backdrive when high inertia, high speed drives are shut down.

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Agricultural Machinery Business Machines Conveyors Cranes and Hoists Dry Cleaning Machines

Pumps and Compressors Textile Machinery Two Speed Drives Washing Machines Wire Winding Machinery

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Food Processing Machines Machine Tools Packaging Machinery Printing Machines

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