Coupling 40972 224999074 2008-07-11T11:36:04Z Gwernol 266416 Reverted edits by [[Special:Contributions/78.39.194.41|78.39.194.41]] ([[User talk:78.39.194.41|talk]]) to last version by 121.246.149.38 :''This article describes a mechanical connection between two things. For other meanings, see [[Coupling (disambiguation)]].'' [[Image:Rotating coupling.gif|frame|right|Rotating coupling]] A '''coupling''' is a device used to connect two shafts together at their ends for the purpose of transmitting power. Couplings do not normally allow disconnection of shafts during operation, however there do exist [[torque limiter| torque limiting]] couplings which can slip or disconnect when some torque limit is exceeded. ==Uses== Shaft couplings are used in machinery for several purposes, the most common of which are the following. * To provide for the connection of shafts of units that are manufactured separately such as a motor and generator and to provide for disconnection for repairs or alternations. * To provide for misalignment of the shafts or to introduce mechanical flexibility. * To reduce the transmission of shock loads from one shaft to another. * To introduce protection against overloads. * To alter the vibration characteristics of rotating units. == Types of shaft couplings == === Rigid coupling === Rigid couplings are used when precise shaft alignment is required; shaft misalignment will affect the coupling's performance as well as its life. Examples: * Sleeve or muff coupling * Clamp or split-muff or compression coupling * [[Flange coupling]] === Flexible coupling === Flexible couplings are designed to transmit [[torque]] while permitting some radial and axial and angular misalignment. Flexible couplings can accommodate angular misalignment up to a few [[Degree (angle)|degrees]] and some parallel misalignment. Examples: * Bushed pin type coupling * [[Universal joint|Universal coupling]] * [[Oldham coupling]] * Bellows coupling — low backlash. * Spider or jaw coupling — elastomeric inserts for flexibility, vibration reduction. * [[Thompson coupling]] * [[Compliant mechanism|Resilient coupling]] ===Torque limiting coupling=== Torque limiting couplings, or [[Torque limiter | torque limiters]], protect systems against overtorque conditions. == Requirements of good shaft alignment / good coupling setup == *it should be easy to connect or disconnect the coupling. *it should transmit the full power from one shaft to other without losses. *it does allow some misalignment between the two adjacent shaft roation axis. *it is the goal to minimise the remaining misalignment in running operation to maximise power transmission and to maximise machine runtime (coupling and bearing and sealings lifetime). *it should have no projecting parts. *it is recommeded to use manufacturer's alignment target values to set up the machine train to a defined non-zero alignment, due to the fact that later when the machine is at operation temperature the alignment condition is perfect == Tools to measure shaft axis alignment condition == * it is possible to measure the alignment with dial gages or feeler gages using various mechanical setups. * it is recommended to take care of bracket sag, parallaxe error while reading the values. * it is very convenient to use laser shaft alignment technique to perform the alignment task within highest accuracy. * is it required to align the machine better, the laser shaft alignment tool can help to show the required moves at the feet positions. ==See also== *[[Clutch]] *[[Laser shaft alignment]] *[[Compression fitting]] *[[Piping and plumbing fittings]] ==External links== *[http://www.unionmillwright.com/shaft.html Shaft Coupling Glossary] *[http://www.roymech.co.uk/Useful_Tables/Drive/Drive_Couplings.html List of coupling types] *[http://www.alignmentsupplies.com Laser Measurement Systems for Shaft & Machine Alignment] *[http://www.skilfabcouplings.com SkilFab Engineering www.skillfabcouplings.com - Leading Coupling Manufacturer] {{mech-engineering-stub}} [[Category:Mechanisms]] [[Category:Hardware (mechanical)]] [[Category:Mechanical engineering]] [[de:Kopplung]] [[fr:Accouplement (mécanique)]] [[sv:Koppling]] [[ru:Муфта (механическое устройство)]] [[he:מצמד]] [[it:Frizione (meccanica)]] [[nl:Koppeling]] [[no:Kobling]] [[pl:Sprzęgło]]