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Formsprag Clutch

Clutch Engineering is an authorized Formsprag Clutch distributor for products including clutches, backstops, and couplings. Along with offering these high-quality products, Clutch Engineering is able to provide technical support from our team of application engineers, ensuring that you have access to expert advice when selecting your ideal product solutions. We specialize in the distribution of many industrial power transmission products and we are proud to feature overrunning, indexing, and backstopping clutches from Formsprag Clutch. They provide superior overrunning clutch technologies for challenging industrial applications worldwide. Their products are specially designed to address the complex needs of many niche industry challenges. Their mechanical solutions can be used for general and special purpose use cases, as the constant qualities they offer are precision manufacturing and reliability. Different modular options are also available, giving you options to find your ideal mechanical solutions.


For over 50 years Formsprag Clutch has been recognized as the world’s leading authority for the design and manufacture of long-life overrunning clutches (Types FSO, FSR, and RL), backstops (Types FHB and LLH), bi-directional clutches, and clutch couplings (Type FW). Formsprag is equipped to provide the broadest range of both sprag and ramp & roller type overrunning clutches and backstops in the world.


These reliable Formsprag products are used in mechanical systems for mining, aerospace & defense, packaging equipment, food processing, material handling, rotary & fixed wing aircraft, pumps, hoists & cranes, and machine tool applications. Additionally, they are used for paper converting machinery on conveyor applications. Clutch Engineering can provide dependable, long-lasting parts and expert engineering support for the toughest of industrial applications. Contact our team with any questions you have about these product offerings, we are happy to provide additional information.

FSO Overrunning Clutches

Formsprag model FSO overrunning clutches from Clutch Engineering are through-shaft mounted. The inner race is driven by a key for these products. Wash-down duty options are also  for these clutches available if necessary. These FSO overrunning clutches are designed for overrunning, backstopping, and light to medium-duty indexing applications. All models contain PCE sprags with Formchrome® and Formsprag “Freeaction” retainers except models FSO 550 & FSO 650. Standard clutches and all C/T clutches are oil lubricated.

Torque range: 275 to 27,000 lb-ft (374 to 36,720 Nm)
Typical applications: Conveyors, dual drive applications

HPI Indexing Clutches

Offered by Clutch Engineering, Formsprag’s HPI indexing clutches are meant for a variety of medium to heavy-duty indexing applications. With these clutch products, reciprocating linear motion can be converted into incremental, uniform rotary motion. Washdown options are also available for these products. Formsprag clutches are designed for long and dependable life. Standard clutches and all C/T clutches are oil lubricated. Where higher inner race overrunning speeds are required, or for applications where maintenance is inadequate, grease lubrication is available. These clutches mount on a through-shaft. The inner race is driven by a key.

Torque range: 275 to 27,000 lb-ft (374 to 36,720 Nm)
Typical applications: Conveyors, material feed applications

LLH Holdbacks

Clutch Engineering offers Formsprag Long Life Holdbacks (LLH) that have the ability to overrun in one direction, allowing rotation, while rotation in the opposite direction is prevented. This functionality is accomplished by a one-piece, quickly detached torque arm fixed to one race. The sprag design is comprised of a full complement of accurately formed sprags filling the annular space. These LLH Holdbacks designed for long life, as the name implies, and they are sealed to protect against airborne contaminants. Formsprag offers two technologies in backstopping designs, Sprag and Ramp & Roller. The ramp & roller design consists of precision machined ramps on the inner race and bearing quality cylindrical rollers filling the annular space.

Torque range: 5,000 to 700,000 lb-ft (6,800 to 952,000 Nm)
Typical applications: Conveyors, bucket elevators, pumps, ski lifts, elevators

FHB Backstopping Clutches

The Formsprag FHB backstopping clutch, offered by Clutch Engineering, is a completely maintenance free product. It has the ability to engage instantaneously and automatically to prevent any reverse shaft rotation. The FHB backstop is mounted on a through-shaft with its inner race driven by a key. Its integral outer race torque arm is also prevented from rotating through a clearance fit interface with a fixed reaction pin. These clutch products are directly interchangeable with FALK Model BIF external high-speed backstops. The reaction pin may also be used to provide axial restraint of the backstop on the rotating shaft.

Torque range: 1,734 to 4,130 lb-ft (2,350 to 5,600 Nm)
Typical applications: Inclined conveyors, bucket elevators, mining applications

FSR Overrunning Clutches

FSR series overrunning clutches from Formsprag are offered by Clutch Engineering for a variety of applications. These are sleeve bearing supported and suitable for general purpose overrunning, indexing, and backstopping applications. Oil lubricated models have a Buna-N oil seal at each end of the clutch which provides positive lubricant sealing. To secure attached parts to the hub, a keyseat and snap-ring groove are provided. These products can be removed for free lubricant flow for clutches operated in an oil bath.

Torque range: 40 to 1,800 lb-ft (55 to 2,448 Nm)
Typical applications: Packaging, material handling

RL Overrunning Clutches

The Formsprag RL clutch from Clutch Engineering permits transmission of driving torque. This applies to both directions. Additionally, it restrains any feedback torque from the driven load from rotating the output shaft. This is available in six sizes and the Formsprag RL Clutch is a sprag type no-back. The outer race diameter is the same size as standard bearing dimensions for easy mounting. There is no backlash from the operation of this clutch product. Models RL-47A through RL-160A are larger units applicable in an extensive torque capacity range. These models require lubrication.

Torque range: 96 to 26,500 lb-in (10 to 3,003 Nm)
Typical applications: Dual drive applications, selective direction overrunning or backstopping applications

FW Clutch Couplings

The FW Series and FWW series clutch coupling is designed for Inner Race Overrunning. These products are offered by Clutch Engineering for a multitude of clutch coupling needs. Formsprag FW clutch couplings are made from an FSO clutch paired with a Form-Flex disc coupling. This enables the clutch coupling to accommodate misalignment in cases of shaft-to-shaft in-line mounting. FW clutch couplings accommodate angular and parallel misalignment, are torsionally stiff, and can couple shafts of different sizes. The FWO and FW C/T Series clutch coupling are designed for Outer Race Overrunning.

Torque range: 65 to 2,520 lb-ft (88 to 3,416 Nm)
Typical applications: Pumps, fans

GFR Modular Clutches

Clutch Engineering offers the Formsprag GFR modular clutch as an excellent low speed backstop for a variety of applications. These units may be used in designs providing oil lubrication and sealing. The outer race of this clutch is designed to support and center any component bored to H7 tolerance. Indexes should not exceed 350 per minute when used in an indexing application. Models GFR and GFRN are identical, except that model GFRN has a keyseat on the outside diameter to transmit torque.

Torque range: 41 to 51,660 lb-ft (55 to 70,000 Nm)
Typical applications: Material handling, conveyors


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