Industrial Ratchet Freewheels and Adaptors

A ratchet and pawl mechanism is used with materials and heat treatment selected for a long operating life, with safe, positive transmission. IRF’s are suited to low speed (up to 150 r.p.m.) overrun applications where shock loads may be encountered, such as Agricultural machinery.

Standard stock units are available in two configurations; as standard sprocket for 1/2 inch pitch chains, or with a drilled flange to fit conveyor rollers, pulleys, or wheels. Standard units have threaded bore to cycle standards, but a range of Adaptors enable fitting to keyed shafting. IRF clutches are also stocked in part-assembled condition for reworking to custom design, including finish parallel bore and keyseat. Many special Industrial Ratchet Freewheels have been manufactured to meet customers’ requirements with torques over 1,000 Nm.

“M” Series Sprag Clutches

The clutches are designed to mount directly on through shafts; the torque being transmitted by a matching key provided with each stock bore; the outer race has a precision ground diameter with tapped holes on each face to enable the fitting of gears, sprockets, pulleys, etc.

Four types of clutch are offered

MG Series – Standard clutch for general overrunning, backstop and index applications, standard oil lubricated with option of grease.

MI Series – Has special sprag assembly designed for high speed indexing. Always oil filled for optimum performance.

MO Series – Fitted with labyrinth seals for minimal drag on higher speed overrun and backstop applications. Always grease lubricated.

MR Series – Utilises a special sprag cage arrangement to allow high speed overrunning of the outer race. Oil lubricated clutch suitable as a higher torque alternative to Roller Ramp clutches.

Vertical Shafts – Clutches suitable for vertical shafting can be supplied – contact Cross+Morse sales office for technical advice.

High Speed/Temperature Operation – Clutches can be provided with a patented venting system for applications subject to high temperature variation or overrunning at high speed.

Backstop Types B200 & B500

B Series clutches are designed primarily as backstops for gearboxes, but have also been used for indexing in the textile industry. The clutches operate directly on customers’ hardened and ground shafts. They consist of a plain outer race with key to locate in housing, and a full complement of sprags activated by two garter springs. The outside diameter is the same as 62 series ball bearing enabling simple fitting beyond the bearing on intermediate or output shafts of gearboxes. Bore sizes range from 16.5 mm to 56 mm for operation alongside bearings 6203 to 6210. Torques up to 1700 Nm can be restrained.

CNAS Clutches

On type CNAS clutches torque transmission from the outer race is by interference fit with the housing bore which needs to be to H6 or J7 tolerance. The housing should be in Steel or high grade cast iron with minimum outside diameter to dimension ‘K’ in the table. Transmission from shaft is by a key with recommended shaft tolerance h6 or j6, except for clutch CNAS 6 where transmission is by press-fit onto shaft with n6 tolerance.

CNFS Clutches

On type CNFS torque transmission from the outer race is via two keys in the end face of the outer race. For good location of the clutch the housing bore should be to H6 or G7 tolerance, except where keys are not used for the torque transmission , when the housing bore must be to K6 tolerance to provide the necessary interference fit. Transmission from shaft is by a key with recommended shaft tolerance h6 or j6.

Our sprag clutches consist of:

1. A high strength carbon alloy steel precision ground Outer Race.
2. A free rotating Bearing Retainer fitted flush with the Outer Race.
3. Hardened Chrome Alloy Steel Balls to provide concentricity and equal distribution of radial support within the clutch.
4. A precision ground alloy steel Inner Race.
5. A moulded Nylon Sprag Cage to equally space the Sprags.
6. Heavy duty Garter Spring located within the Sprag Cage ensures accurate Sprag engagement.
7. High Carbon Steel profiled Sprags support the compressive loads when the clutch is transmitting torque.
8. Light Retaining End plates attached to the outer race help retain lubricant and protect clutch components from the environment.

Types with suffix RS include a rubber seal in the bore of the retainers to provide a complete sealing of the clutch.Type CSK-RS is constructed with wider races to enable use of a full rubber seal for maximum protection.

Clutch types CKKN and CSKN-RS have keyways on the inner races to enable optional fitting with a key instead of press-fit to the shaft. The outer is still fitted into the housing with a heavy press fit, the bearing clearance being modified to allow for one race only having the heavy press-fit. Clutch types CKKNN have a keyway on the outer race as well as the inner, to allow assembly of the clutches with only a light interference fit. These clutches have the same build as the CKK series, with a high performance sprag assembly combined with a deep groove bearing,to provide a compact, high torque, but low cost freewheel, suitable for both overrun and backstop applications. The lack of press-fit makes them unsuitable for accurate indexing. Clutches with an RS suffix include a rubber seal in the bore of the retainers to provide complete sealing. Type CSKN-RS are constructed with wider races to enable the use of a full rubber seal for best protection.

These clutches have no integral bearings, and external bearing support is thus required to accurately align the inner and outer races for correct freewheel function.

AA Series Clutches

On the AA series clutches torque is transmitted from the shaft to the inner race by a standard key, and from the outer race to the connecting part by high tensile bolts. The outer race has common dimensions with the AGF series of clutches, and so can when used as a backstop utilise the F4 end flange of this series to provide a fully sealed unit. The fit for centering of the outer race should be H7 tolerance.

AEF Series Clutches

On the AEF series clutches torque is transmitted from the shaft to the inner race by a standard key, and from the outer race to mating part by two face mounted keys offset by 180˚. The mating bore for the outer should be to K7 tolerance. If a housing with R6 tolerance is used the end keys can be omitted.

The ANF and ANR series Clutches are high torque Roller Ramp Clutches for applications within an encased lubrication system. Torque is transmitted by a keyway in the bore and two keys on the end faces of the outer race.

ANF Clutches

The ANF clutches require their housing to have bearing support with the shaft in order to provide the necessary concentricity within the clutch. The tolerance of the housing bore ‘D’ should be H7 or G7, and the shaft h6 or j6.

ANR Clutches

The ANR clutches incorporate their own bearings to centre the inner and outer races. Sizes ANR 8 to ANR 20 utilise a steel on steel plain bearing, whilst larger sizes incorporate two 160 series ball bearings. The tolerance of the housing bore ‘D’ must be H7 or G7, and the shaft h6 or j6.

Roller Ramp Clutch with Ball Bearings AGF/AGFN

The AGF Freewheels can be used with special flanges providing these axially locate the bearings. All standard flanges include oil seals for retention of lubricant, but the clutches can be run within an oil filled transmission case without seals.

Type AGFN incorporates a keyway in the outer race for torque transmission, enabling simple connection of gears, sprockets and pulleys.

Combination of AGF Series roller ramp clutches with a selection of end flanges

Provides a versatile range of clutches complete with own bearing support and integral lubrication system. Flanges can be combined as required to suit most applications, the following combinations being most common.

AGF-F1-F2 is most popular combination, enabling easy mounting of pulley, sprocket or gear on outer race. F2 flange enables re-lubrication.

AGF-F2-F7 is designed to enable connection of flexible couplings and universal joints. Can also be used to locate on m/c frame as backstop. In this application F4 cover could be used instead of F2 plate-ref. p. 12.

AGFN-F5-F6 enables simple fitting of gears, sprockets, pulleys, etc. with positive drive through key on outer race.

Type AGF Clutch assembled with Torque Arm End Flange

The combination of an AGF series roller ramp clutch with F3 and F2/F4 flanges provide a unit complete with support bearing and its own integral lubrication system. The units are primarily intended for backstop applications, but can also be used as reciprocating arm on indexing applications.

Type KI – Miniature Roller Ramp Freewheel

The KI Series are self-contained units with inner race, springs and rollers contained in a polyamide cage suitable for temperature range -40°C to +120°C. Designed for small office Equipment and packaging machines, the clutch can be pressed onto shaft to r6 tolerance, with outer driving any steel component with H7 tolerance bore and bearing support.

Type ASK – Combined Roller Bearing and Roller Ramp Clutch

The ASK series are roller ramp freewheels supported by two rows of roller bearings, the complete unit being within a dust proof enclosure conforming to 60 series bearing dimensions. They are supplied ready grease lubricated. Torque transmission is by press fit with outer housing to K6 tolerance and shaft to h6 or j6. These units must not be subject to axial loading.

Type GFK – Ball and Roller Bearing Sprag Clutches

The GFK clutch combines a sprag unit with a roller bearing and ball bearing into a unit which dimensionally equates to a 59 series bearing. The design provides high torque capacity and bearing strength within a compact unit. Torque transmission is by press fit with outer housing bore to R6 tolerance and shaft to p5 tolerance. The unit has operating temperature range of -40°C to +130°C, and is supplied ready grease lubricated. For dusty environment external sealing is required.

BW Sprags Elements

The sprags are individually energised by a brass ribbon spring, but their relative movement to one another is controlled by the double cage design to ensure load sharing and prevent de-phasing of individual sprags. Standard sprags are manufactured from 52100 bearing steels. Two basic designs of sprag are available, disengaging types (Diseng.) where the sprag lifts-off from the inner race when the outer is rotated at high speeds, and engaging types (Eng.) where the contact forces between sprag and inner race increase as the outer race is rotated. The sprag element is designed to rotate with the outer housing, this being essential for correct operation of the unit. In applications with rapid speed changes additional clamping of the element to the housing is essential and this is achieved by clips/T bars fixed to the outer cage.

Sprag elements are best applied where high torque transmission is required, but space is limited, and where direct installation into machine parts is required. The clutches double cage design makes them particularly suitable where torsional vibrations are present. Ability to control the operating characteristics has made them suitable for a wide range of applications including turbine starters, marine drives, gearbox backstops, winches, printing machines and machine tools.

Backstop Clutches

All Clutches have an integral Torque Arm with a slot to engage with a bolt or bar fixed to the machine framework.(except CR/BV90 to 120). Units are greased for life, and fitted with labyrinth seals for operation in dusty conditions. Units can be mounted on horizontal or vertical shafts, of 20mm to 120mm, and with torque up to 18450Nm.

CR/BW series have caged Sprags to provide high torque capacity at a low unit cost. Bearing support is by plain metal bushes, with O’ Ring seals to retain the grease, whilst excluding dust and moisture.

CR/BT series also use Sprags for torque transmission, but inter-spaced with rollers to provide bearing support. Whilst this reduces torque capacity a little, the superior bearing support enables higher shaft speeds and longer life.

CR/BV series use Roller Ramp design for torque transmission providing a long service life. Sealing is by shield protected labyrinth seals. These units can also be used for slow speed indexing applications.

All these clutches are totally maintenance free, and therefore suited to remote locations.

Sprag Clutches PB & HT

PB Sprag Clutches feature precision formed sprags for maximum torque capacities combined with long life. The clutches have an outer race designed to simply attach sprockets, gears or pulleys with a plain bearing to support high radial loads. They are pre-lubricated with grease suitable for temp range -10 to +50°C. Oil lubricated clutches can also be supplied to order (except PB3A). These clutches are suitable for general purpose overrunning and indexing applications.

HT Sprag Clutches are designed for end of shaft applications, being retained on the shaft by a deep groove ball bearing with snap ring in outer race locating in recess dia. D. The outer race of the clutch is tapped for attaching sprocket, gear or ratchet arm Intended primarily for indexing applications, the clutches can also be used for backstop and overrun applications providing the inner race is overrunning.