Formsprag Clutch, together with its sister company Stieber Clutch in Germany, is the world’s leading designer and manufacturer of Overrunning Clutches and Backstops for use in numerous Industrial Power Transmission applications including Conveyor & Conveying Equipment, Food Processing Machinery, Gear Reducers, Hoists & Cranes, Mining Machinery, Machine Tools, Paper Converting Machinery, Packaging Machinery, Pumping Equipment, and many other types of Specialty Machinery.
Formsprag and Stieber offer the broadest range of both Sprag and Ramp & Roller type overrunning clutches and backstops available world-wide.
FRB Series Backstopping Clutches
Excellent for use as backstops by mounting the clutch’s inner race on the rotating shaft and attaching or anchoring the clutch’s outer race with a torque arm to a stationary member of the equipment. The Model FRB can also be used in applications that require low driving speeds and high inner race overrunning speeds.
FSA model clutches are designed for low speed overrunning and indexing applications in the torque range from 38,000 to 500,000 lb.ft . FSA clutches are oil lubricated and equipped with lip-type seals.
FSO Overrunning Clutches
FSO clutches are used on multi-speed, one direction only conveyors for non-destructive accommodation of speed differentials in powered rollers and belt drive systems. The FSO clutch allows the slower speed zone to over-speed during the transitional period without back driving the slower drive system.
These clutches are available with FDA approved food grade greases and a variety of surface coatings required for wash down duty.
HPI Indexing Clutches
HPI clutches are mounted on the head shaft and translates the reciprocating motion from the crank mechanism into incremental motion in one direction,advancing the conveyor a uniform distance with each drive stroke and then overrunning in the opposite direction on the return stroke. These clutches are available with FDA approved food grade greases and a variety of surface coatings required for wash down duty.
ASK is a ramp & roller type clutch bearing supported by two rows of roller bearings.
Nominal outside envelope dimensions are the same as a 60 Series bearing.
The CSK Series is a sprag type clutch integrated into a 62 Series ball bearing (except sizes 8 and 40).
CSK . .2RS clutches are .197” (5mm) wider than a standard 62 Series bearing, as they are equipped with lip seals for washdown applications .
CSK . .P has the same construction and outside dimensions as type CSK, but has a keyway on the inner race .
These clutches can be mounted on a shaft with recommended k6 tolerance and the outer race must be pressed into a rigid housing with a recommended N6 tolerance . The resulting housing and shaft diameters must be checked to ensure that the bearing has adequate radial clearances .
CSK . .PP features a keyway on both the inner and outer race . The recommended mounting tolerances are k6 on the shaft and K6 in the rigid housing . A h6 tolerance on the shaft or H6 in the housing are also acceptable for a light press fit assembly . Always check to ensure that the bearing has adequate radial clearances.
Model GFK is a sprag type clutch integrated into a 59 Series ball bearing.
This design provides high torque capacity for minimal outside diameter.
It is a bearing supported type, shipped grease lubricated.
Oil bath lubrication is also possible if the original grease is first removed by flushing the clutch with a suitable solvent.
Whatever the lubrication type, seals should be provided, as illustrated below.
Torque transmission must be ensured by a press fit assembly into a rigid outer housing with R6 tolerance, and onto a shaft with p5 tolerance.
The total press fit on the GFK should not exceed the internal clearance for the model as listed in the Internal Clearance Column.
Model AS is a ramp & roller type clutch, non-bearing supported. Bearings are required to support axial and radial loads. Lubrication and sealing are required. Nominal outside dimensions are the same as a Series 62 ball bearing.
Model ASNU is a ramp & roller type clutch, non-bearing supported. Bearings are required to support axial and radial loads. Lubrication and sealing are required.
Nominal outer diameter is the same as a Series 63 ball bearing.
Model DC is a sprag-type dual cage retainer assembly without inner or outer races. It must be installed in a design providing races, bearing support for axial and radial loads, lubrication and sealing.
DC races are offered for use with the DC retainer assemblies. The retainer assembly and races make a nonbearing supported clutch. Bearing support for axial and radial loads must be provided along with lubrication and sealing.
FS-50 & FS-20 Series
Series 20 and 50 clutches provide all the outstanding features of the Formsprag design for backstop applications with the exception that the customer supplies his own inner race, and provides the concentricity between the races.
This assembly is particularly advantageous on such applications as gear reducers where the backstop can be incorporated into a bearing bore and an extension of an existing shaft can be used for an inner race.
The outer surface of this clutch is basically the same as the outer surface of a standard bearing. The tolerance on the outer diameter is held to insure a proper fit (without pressing) into a continuation of the bore which accommodates the adjacent bearing. The tolerance on this bore should follow the bearing manufacturer’s recommendation for the bearing used . Taper within this bore should not exceed .0002 inch per inch.
Model RSCI is a centrifugal throwout sprag type overrunning backstop with the inner race rotating. Only the inner race is designed for overrunning. The RSCI is not a self-supported design, therefore bearings must be provided to ensure concentricity of the inner and outer race and to support axial and radial loads. This model makes an excellent long-life backstop as there is no contact of the load surfaces during normal running of the equipment.
FS-02, 04, 05 Series
These small clutches are ideal for use in all types of small machines and precision instruments and may be used for overrunning, indexing and backstopping applications . They are sleeve bearing clutches .
FS 02 through 05 clutches are shipped from the factory lubricated for life with Fiske Brothers Lubriplate Low-Temp grease .
Models FS-02 and FS-04 are secured to the Shaft by a roll pin provided with the clutch . Both the hub and the O.D. of the outer race are ground to close limits and may be used to mount attaching parts .
Model FS-05 is driven from the shaft by (6) a .125” key. Parts should be mounted on the ground O.D. of the clutch. Snap rings 30 and Woodruff key are provided.
There are eight sleeve-bearing clutch models suitable for general purpose applications—overrunning, indexing and backstopping. A keyseat and snap-ring groove are provided to secure attached parts to the hub, which is ground as a mounting surface. Oil lubricated models have a Buna-N oil seal at each end of the clutch which provides positive lubricant sealing. They can be removed for free lubricant flow if clutch is operated in an oil bath.
The shaft must extend through the full length of the clutch and must be held to recommended limits because the sleeve- bearing in the outer race rides on the shaft.
CDU (Continuous Drive Unit) Series Overrunning Clutches are designed to be robust for the most difficult applications. CDU Series Overrunning Clutches are intended for use in continuous overrunning applications where the system cannot be shut down for maintenance and for applications in extremely harsh and dusty environments such as coal handling systems. A CDU consists of an FSO overrunning, sprag clutch installed in a foot-mounted housing which encloses a generous supply of oil.
FS 100 200 300 Series | Formsprag Clutch
Generally used as an indexing clutch where a compact package is desired. A snap-ring bearing must be inserted before installing. An adequate seal or cover must be provided at the open end to retain lubricant. Shaft end must be turned down and threaded to accommodate bearing and lock nut.
Drawworks clutches are designed for use with Hydromatic® brakes on drilling rigs. They are available over a range of torque capacities and provide reliable performance in original equipment or as a replacement for a type A clutch.
The Model HBG series are designed for use on Hydro-dynamic Brakes on drilling rigs, using Ramp & Roller Technology which offers better availability.
The HPO series is especially designed for high speed outer race overrunning applications, such as high speed dual drives or standby drives. HPO clutches are grease lubricated and equipped with labyrinth seals. Formchrome® sprags and special retainers are incorporated for maximum service life and speed capability. These clutches mount on a through shaft, with the inner race driven by a key. The ground O.D. of the outer race is designed as the mounting surface for attaching parts and is concentric with the bore. Tapped holes are provided in each end of the outer race for securing parts to the clutch.
Available in six sizes, the Formsprag RL Clutch is a sprag type no-back which permits transmission of driving torque from input to output shaft in both directions of rotation, but restrains any feedback torque of the driven load from rotating the output shaft in either direction. The RL Clutch is extremely simple in design and has a minimum number of moving parts. The outer race diameter is the same size as standard bearing dimensions, thus simplifying mounting and providing maximum strength in the assembly.
Model SB (shaft bore) automatic pump backstopping clutches feature a high torque density and require no adjustments or controls.
SBI Series In-line Mounting Ball Bearing Supported clutches are comprised of an HPI clutch with an extended shaft (inner race) for in-line mounting. The extended shaft provides a convenient way to mount a coupling to accommodate the misalignment in the in-line application. This design is intended for applications with medium to heavy-duty indexing requirements. They are oil lubricated and equipped with lip type seals. Grease is available. Increased overrunning speeds are possible with clutches having steel labyrinth grease seals.
Model FHB is a high speed, centrifugal throw-out (C/T) Sprag type backstop with internal sealed ball bearings. This self-contained design is completely maintenance free. It requires no re-lubrication, no external control, and no adjustment. It engages instantaneously and automatically to prevent any reverse shaft rotation. Model FHB operates at higher overrunning speeds and holds greater torque loads than competing backstops. A larger number of torque transmitting C/T Sprags reduce the hertzian contact stresses during backstopping leading to longer life than is possible with shoe designs.
The FHB backstop is mounted on a through-shaft with its inner race driven by a key, and its integral outer race torque arm prevented from rotating through a clearance fit interface with a fixed reaction pin. The reaction pin may also be used to provide axial restraint of the backstop on the rotating shaft. Typical uses for the Model FHB backstop include inclined conveyors, bucket elevators, and other applications where a rotating shaft must be absolutely prevented from rotating in a reverse direction, as commonly found in mining, aggregates, material handling, and other industries. The high speed capability of the unit make this backstop ideal for mounting on double extended input shafts of gear reducers. The overrunning speed of the rotating shaft should be greater than 400 RPM to assure C/T Sprag “lift-off”.
Horizontal Fan Backstops/Vertical Fan Backstops
Models HFB and VFB are backstopping clutching designed to prevent reverse rotation of shafts in applications that have large shaft diameters of up to 6.0 inches and low backstopping torque requirements. HFB & VFB backstops have Sprag clutch technology with high inner race overrunning speed, are ball bearing supported and protected with integral lip seals. The clutch housing is prevented from rotating with a torque arm and is mounted on a stub shaft with a locking ring for easy mounting. Clutches are selected by shaft size and torque requirement.
HSB units are intended for use as backstops on the high speed shaft or intermediate shaft of reducers and as holdbacks on the headshaft of conveyors. They use standard FSO Series clutches with the addition of an oil reservoir made from an aluminum casting with cooling fins. HSB models are designed to permit free oil flow between clutch and reservoir to provide increased cooling capacity and increase backstop life.
Models LCB-200 and 400 are economical, low-torque clutches designed to prevent problems associated with windmilling in fan applications. Units can be installed on vertical or horizontal fan shafts without the use of a key. The clutches can accommodate a range of shaft diameters between 1-7/8” and 5”. Units are maintenance-free and easy to install.
Formsprag Long Life Holdbacks (LLH) are designed for use on conveyor heads hafts, bucket elevators, pumps, or any other machinery where reverse rotation must be positively prevented. LLH holdback clutches are ready to install. They are equipped with grease labyrinth protected oil seals that positively prevent airborne contaminants from reaching internal seals and parts.
Model RSBW is a specialized backstop based on a DC sprag type dual cage retainer assembly. It is self contained utilizing a combined outer race and torque arm, which incorporates plain bearings suitable for low rotational speeds, and seals using shield protected O-Rings. Primarily used as a backstop, this model provides high torque capacity with a minimum space.
The model AL..clutch assembled with the F2 and D2 covers provides a versatile clutch assembly. The F2 cover provides mounting holes countersunk from the outboard side which are used to secure and drive a gear or pulley mounted over the outer race. This mounting configuration provides the highest radial load capacity as the line of force from the gear or sprocket is located between the clutch bearings. The D2 cover encloses the other end of the clutch for through shaft mounting.
The model GFR clutch assembled with the F3 and F4 covers results in an excellent low speed backstop. The F3 cover encloses one side of the clutch and provides the torque arm with integrated restraining bolt necessary for backstopping applications. The F4 cover encloses the other side of the clutch and provides extra room for end of shaft restraint as well as added oil capacity.
The model RINZ clutch assembled with the G5 covers on both sides provides a durable easy-to-use design. The G5 cover provides axial restraint of a gear or pulley mounted on the outer race. Torque is transmitted to the gear or pulley by the key located in the outer race outside keyseat.
Model AL..KEED2 is a ramp & roller type clutch coupling, self contained, sealed and bearing supported, using two 160 Series bearings. In this design, a standard AL clutch is connected to a KEE flexible coupling for in-line mounting. The KEE model is a rugged coupling, economical and suitable for many applications. D2 cover is used to enclose the unit.
Model AL..KMSD2 is a ramp & roller type clutch coupling, self contained, sealed and bearing supported, using two 160 Series bearings. In this design, a standard AL clutch is connected to a KMS flexible coupling for in-line mounting. The KMS model is a rugged coupling, economical and suitable for many applications. D2 cover is used to enclose the unit.
FW clutch couplings are comprised of an FSO clutch and a Form-Flex disc coupling to accommodate misalignment for shaft-to-shaft in-line mounting. FW clutch couplings accommodate angular and parallel misalignment, are torsionally stiff and can couple shafts of different sizes. Increased clutch coupling speeds are possible with FSO clutches having steel labyrinth grease seals. C/T is ideal for applications with high speed outer race overrunning and low drive speed.
For in-line shaft applications FWW clutch couplings are comprised of an FSO clutch with a Form-Flex disc coupling to accommodate misalignment present in shaft-to-shaft in-line mounting. FWW clutch couplings are ideal for applications where the torque requirement is low in comparison to the shaft diameters. Both bore diameters in the coupling hubs are larger than the respective clutch bores. C/T sprags are available. Increased clutch-coupling speeds are possible with FSO clutches having steel labyrinth seals.
Model RIZ..ELG2 is a centrifugal throwout sprag clutch with a coupling for in-line shaft mounting applications. In this design only the inner race can overrun. They are typically used in creep drives, where the overrunning speed is high, but the drive speed low, and does not exceed the maximum driving speed specified in the table.
Interested in one of our products? Drop us a line!