Clutch Functions and Applications

All Formsprag/Stieber clutches described is based on the accumulation of many are divided into three basic types of in this catalog are “overrunning” clutches, years of experience in the design, ­ applications for which they are intended . i .e ., they will drive in one direction but con­struction and application of The three basic applications are: overrun (freewheel) in the other direction . overrunning clutches . In physical The preparation of a catalog such as this appearance, the Formsprag/Stieber • Overrunning can be undertaken only by a company catalog overrunning clutches are all very • Indexing having very broad experience in all much alike . However, different types • Holdbacks or Backstops aspects of the use and application of of applications will involve differing overrunning clutches . load characteristics­ and will call for These three categories are described in variations in the technical details of clutch greater detail under those headings in this Formsprag/Stieber is such a company, construction . For this ­reason the clutches catalog . and the information given in this catalog

Overrunning clutch Indexing clutch Backstopping clutch

This class of applications is typified by In this type of application, re­cip­ro­cat­ing In backstopping or holdback* applications, standby and compound drives . For motion applied to the driving race is one race is always fixed to a stationary ex­am­ple, a steam turbine and a standby trans­formed into intermittent motion in ground member . The function of the electric motor may be con­nect­ed to a only one direction at the driven race . For clutch is to permit ro­ta­tion of the sin­gle ­driven shaft through overrunning example, if a pinion is connected to the mechanism, con­nect­ed to the other clutches . The shaft can then be driven by driving race, a rack meshing with the race, in one di­rection only, and to prevent either the turbine or the motor or both with pinion can give reciprocating mo­tion to any ro­tation in the reverse di­rec­tion at no further modification of the installation . the driv­ing race . The clutch will then all times . Although the clutch nor­mal­ly The turbine drive clutch au­to­mat­i­cal­ly ad­vance or “index” the work (driv­en race) overruns most of the time, it is re­ferred to engages when the tur­bine starts to drive, on each forward stroke of the rack, but as a ­holdback or backstop in conveyors, but au­to­mat­i­cal­ly over­runs when the load will not return or back-up on the return gear reducers and sim­i­lar equipment is transferred to the electric motor . stroke of the rack . because its function­ is to pre­vent reverse rotation . Considerations Considerations *“Holdback” is a name given to a back­stop clutch when mounted on an inclined con­vey­or • Type of motor • Number of cycles/min head shaft. • Max starting torque • Index angle • Internal combustion engines, • Nominal torque please consult Formsprag • Inertia (WR2) of the driven masses Considerations • Nominal driving torque • Accelerations of the driving • Motor breakdown torque • Range of driving speed member • Maximum dynamic reverse torque • Inertia (WR2) of the driven masses • Number of indexes during due to elasticity of the locked parts: • Range of overrunning speed service life elastic belts, shafts of more than • Number of starts during service life • Shaft diameter 9 feet (3 meters) long • Shaft diameter • Range of overrunning speed Applications • Number of torque applications during service life Applications • Metal stamping • Shaft diameter • Dual motor/engine drives • Pressworking • Conveyor belts • Packing machines • Creep and starter drives • Indexing tables Applications • Disengagement of centrifugal masses­ • Assembling machines • Inclined conveyors • Printing machines • Escalators • Pumps • Gear drives • Fans

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Backstopping VFB & HFB models provide automatic backstopping for fans to prevent wind milling when the fan is turned off, actuates instantaneously to prevent any reverse rotation .

Dual Drive FSO clutches are used in dual drive applications to provide instantaneous clutching from one drive to the other in case of the failure of either .

Indexing Indexing clutches are used to con­vert re­cip­ro­cat­ing linear Backstopping mo­tion to in­cre­mental­ rotary motion for conveyor or ­ The LLH Holdback clutch is used to backstop (prevent ma­te­ri­al feed ap­pli­ca­tions . reverse rotation) the incline conveyor in a material Clutch Models: HPI, AL ­handling application .

Clutch-Couplings Clutch Couplings are used for dual drive of a pump or fan, and when there is a need to connect inline shafts . Backstopping The clutch coupling prevents backdriving of the other drive source when operating at motor speeds . Clutch FHB backstops are mounted on the double extended couplings allow for the tran­si­tion from one drive source input shaft of gear reducers and provide instantaneous to an­oth­er without controls . automatic backstopping to the drive system for typically Clutch Models: FW, FWW, ALKMS, RIZEL,AL . .KMSD2, inclined conveyors and bucket elevator applications . RIZ . .ELG2

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