Types And Uses Of Coupling Devices Engineering Essay

Types And Uses Of labor union Devices Engineering EssayA jointure is a device utilize to connect cardinal cavils together at their ends for the purpose of contributeting power.In machinery, a device for providing a connection, readily broken and restored, mingled with two adjacent rotating shafts.A brace may bring home the bacon either a rigid or a flexible connection the flexibility may permit mis conjunctive of the connected shafts or provide a torsionally flexible (yielding) connection, mitigating effects of shockCouplings do not normally tolerate bookonnection of shafts during operation, though there do exist torque restricting couplings which can slip or disconnect when some torque limit is exceeded.A common fiber of rigid coupling consists of two mating stellate flanges (disks) that be attached by key-driven hubs to the ends of the shafts and bolted together through the flanges. Alignment of the shafts is usually achieved by means of a short cylindrical projectio n (rabbet joint) on the hardihood of one flange that fits snugly into a circular recess on the face of the another(prenominal) flange.The concatenation coupling consists of two hardened-steel sprockets, one on distributively shaft, with a nylon or metal roller chain wrapped around the closely aligned sprockets and connected at the ends. Clearances mingled with the sprocket teeth and the chain allow for a small do of shaft misalignment.For connecting shafts whose axes intersect but atomic number 18 inclined to one another at a larger tip than a flexible coupling can nurse, universal joints argon used. The most common of these is the Hooke, or Cardan, joint, which consists of two yokes attached to the shaft ends and a cross-shaped connecting member.UsesShaft couplings be 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 separatelty such as a motor and reservoir and to pro vide 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 rampart against overloads.To alter the shiver characteristics of rotating units.Types of shaft couplingsDrive couplingsA coupling is used to connect two in-line shafts to allow one shaft (driver) to drive the second shaft(driven) at the same speed. A coupling can be rigid or, more normally, it can be flexible allowing relative radial, axial or angular battlefront of the two shafts. Unlike the clutch the coupling transmission is not designed to engage-disengage as a normal operationCoupling TypeCoupling typeDescription buckramFlange locked onto each shaft. One flange with recess and the other with matching hydrant. Flanges bolted together to form rigid coupling with no border for relative radial, angular or axial movement of the shafts.Muff CouplingLong cylindrical coupl ing bored and keyed to fit over twain shafts. Split axially and clamped over both shafts with recessed bolts. Rigid coupling for transmitting high torques at high speedsBeam CouplingSingle spot cylindrical coupling with a hole bored through its entire length. Each end bored to suite the relevant shaft. The helical slot is machined in the coupling in the central region. The reduces the coupling stiffness. The coupling is positive with some flexibility.PinAs rigid coupling but with no recess and spigot and the Bolts replaced by pins with rubber bushes. Design allows certain flexibility.Flexible Rubber discAs rigid coupling except that a thick rubber disc bonded between steel plates is located between the flanges. The plates are bolted to the adjacent coupling flanges.SpiderBoth half of the couplings have three shaped lugs . When the coupling halves are fitted together the lugs on one half fit inside the spaces between the lugs on the other side. A Rubber insert with six legs fits wi thin the spaces between the lugs. The drive is by the lugs transmitting the torque through the rubber spider spacer This coupling is only used for low power drives.Bibby CouplingThe outer flanges of the two half couplings are serrated. A spring fits into the serrations connecting the two halves.Chain CouplingFlanges replaced a sprocket on each shaft. The coupling is by a semidetached house chain wrapped over both adjacent cnoupling.Gear CouplingBoth coupling halves have a raised rim machined as an outside(a) gear. The sleeve which couples the two shafts comprises two halves bolted together, each half having a machine internal gear. This coupling requires lubrication. The coupling is capable of high speeds and high power capacity.Metastream CouplingCoupling halves connected via stainless steel diaphragms. High speed high torque capability with good dynamic vestibular sense. Single coupling will accommodate angular and radial misalignment and fitted in pairs also allows lateral mis alignment.Fluid CouplingBased on both coupling halves having vanes within a housing containing sticky fluid. The rotation is transmitted from one side to the other via the viscous fluid. the coupling provides a soft start.Universal CouplingCoupling which allows large angle between drive halves(20-30o). Generally based on a yoke mounted on each shaft . Between to yokes is mounted a trunnion cross. Needle bearings are used at the bearing points between the cross and the yokes. These type or units are used in pairs on carden shafts. Uses widely on rear vagabond drive vehicle propshaftsUniversal Coupling-Uni-JointSimplest type of coupling which allows large angle between drive halves. Each side of coupling includes protruding pins. The halves of the coupling are fastened in a pivotting assembly. At all angles up to about 40othe pins interlock with each other and rotation on one half forces the other half to rotate. Low power use only . Not smooth. Not reliable. Really only suitable fo r remote manual operations.Rigid couplingRigid couplings are used when precise shaft alignment is required shaft misalignment will affect the couplings performance as well as its life. ExamplesSleeve or muff couplingClamp or split-muff or compression couplingFlange couplingFlexible couplingFlexible 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 degrees and some fit misalignment. ExamplesBushed pin type couplingUniversal couplingOldham couplingBellows coupling low backlash.Spider or jaw coupling elastomeric inserts for flexibility, vibration reduction.Thompson couplingResilient couplingDisc couplingSome applications like printing machines, roll forming machines, laminating machines, corrugated paper machines and paper making machines require an complete and variable parallel offset. For these machines the coupling Schmidt-Kupplung is a solution.Torque li miting couplingTorque limiting couplings, or torque limiters, protect systems against overtorque conditions.Requirements of good shaft alignment / good coupling setupit 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 tap power transmission and to maximise machine runtime (coupling and bearing and sealings lifetime).it should have no projecting parts.it is recommended to use manufacturers alignment target values to set up the machine train to a delineate non-zero alignment, due to the fact that later when the machine is at operation temperature the alignment condition is perfectTools to measure shaft axis alignment conditionit is achievable 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 precise convenient to use laser shaft alignment technique to perform the alignment task within highest accuracy.it is required to align the machine better, the laser shaft alignment tool can help to show the required moves at the feet positions.Coupling alimentation and failureCoupling maintenance is generally a simple(a) matter, requiring a regularly scheduled inspection of each coupling. It consists ofPerforming visual inspections, checking for signs of wear or fatigue, and cleaning couplings regularly.Checking and changing lubricant regularly if the coupling is lubricated. This maintenance is required annually for most couplings and more frequently for couplings in adverse environments or in demanding operating conditions.Documenting the maintenance performed on each coupling, along with the date. sluice with proper maintenance, however, couplings can fail. Underlying reasons for failure, other than maintenan ce, includeImproper installationPoor coupling selectionOperation beyond design capabilities.The only way to improve coupling life is to understand what caused the failure and to correct it prior to installing a new coupling. Some external signs that indicate potential coupling failure includeAbnormal noise, such as screeching, squealing or chatteringExcessive vibration or wobbleFailed seals indicated by lubricant escape or contamination.Checking the coupling balanceCouplings are normally balanced at the factory prior to being shipped, but they occasionally go out of balance in operation. Balancing can be difficult and expensive, and is normally done only when operating tolerances are such that the effort and the expense are justified. The amount of coupling unbalance that can be tolerated by any system is dictated by the characteristics of the specific connected machines and can be determined by detailed analysis or experience.