Chains: Types, Advantages, and Disadvantages PDF

CHAINS oWhat are chains? oWhat types of chains? oWhat are chains used for? oWhy choose chains?  NUMEROUS TYPES OF CHAIN o There is decorative “what you talkin bout chain fool” o Ball and chain “I pity o Transport chain the fool” o Ladder chain o R...

CHAINS oWhat are chains? oWhat types of chains? oWhat are chains used for? oWhy choose chains?  NUMEROUS TYPES OF CHAIN o There is decorative “what you talkin bout chain fool” o Ball and chain “I pity o Transport chain the fool” o Ladder chain o Roller chain  ROLLER CHAIN o Roller chain employs principles of anti-friction roller bearings. o Used for power transmission throughout machine industry. o Available in tremendous variation of configuration and size  FOCUS HERE o Roller chain  Used in power transmission application o Types include  Roller  oConveying chains pin and/or plate Used in material handling  Offset functions  Pintle  Mill oTypes include  Drag Tabletop Mat-top  ROLLER CHAIN: o Working load is carried by the side plates (link plate and pin plate.) o The pins, rollers, and bushings are subjected to bending and shearing forces introduced by the sprockets. o With large pitch roller chains, there are limits on operating speed, but they are capable of transmitting greater horsepower. o Available in multi pitch and self lubricating.  OFFSET SIDEBAR, PINTLE, MILL, AND DRAG CHAINS o Offset sidebar chain is designed for extreme power transmission or conveying service. Also known as welded steel chain. o Pintle, mill, and drag chain are considered engineered class chains with an offset construction and integral side plates and barrels, used under high load or power transfer under shock loading. Pintle Mill Drag Chain  LEAF CHAINS o Leaf chains are the robust multi plated roller chains found on lift truck lifts. WHY CHOOSE ROLLER CHAIN FOR POWER TRANSMISSION APPLICATIONS OVER OTHER FORMS OF POWER TRANSMISSION?  WHY ROLLER CHAIN Advantages Disadvantages  Inexpensive Lubrication critical  Size availability Dirty  Length High in  Highly efficient maintenance  Simple to work with Noisy  Versatility Speed limitations  Positive engagement Backlash  Advantages: o Relative low cost : chain and sprockets are inexpensive Readily available, less down time Easily configured with inexpensive tools with very little time cost o Size availability:  Different sizes for different load ratings and applications  Lengths are easily adjusted with chain break tool and stretching tool using a master link  Added strength and load capacity by stacking chains  Advantages: o Length variances: Chain can be broken to the desired length or assembled to the desired length from shorter sections using a master link. Advantages: o Simple to work with: Few basic assembly and disassembly tools o Versatility: Available in many configurations  https://www.youtube.com/watch?v=ex TXdIhCMFc VERSATILITY DISADVANTAGES  Lubrication critical  Dirty  High in maintenance  Noisy  Speed limitations  Backlash  LUBRICATION o Purpose:  Reduces wear between parts  Cushions load impact  Dissipates heat  Retards corrosion  Flushes away contaminant particles o Lubricant viscosity should be low enough to flow on and through the chain, but stick well enough to the surfaces of the chain during transport. o Beware of additives which can coke and leave behind varnish.  LUBRICATION TECHNIQUES o IMERSION WITH o Oil level is at the pitch line of the chain, but never completely immersed. DISK TRANSFER  LUBRICATION TECHNIQUES oRESERVOIR AND o Drip lubrication can be accomplished using a brush, spout, or drip mechanism, and should only be lubricating the chain at specified intervals, typically 8 hours. Drip systems are used in clean environments. DRIP SYSTEM  LUBRICATION TECHNIQUES o PUMP AND SPRAY oBRUSH APPLICATOR  OIL FREE? o Lubrication free with oil impregnated sintered steel bushings http://tsubaki.eu/news/2012/01/tsubaki- leads-the-lube-free-market-with-lambda- chain/  HIGH MAINTENANCE o WHY ? oSome automatic Dirt lubricators wash away dirt oChain tension Lubrication can be addressed with idler assistance Tension  YOU’VE DECIDED ON CHAIN DRIVE o Steps to choosing the appropriate chain What is your application? What is your environmental consideration? What type of chain? What size of chain? How will you perform Preventative Maintenance (PM)?  NOMENCLATURE OF CHAINS o Components of a chain include the  Roller link plate  Pin link plate  Roller  Pin  HOW TO SIZE ROLLER CHAIN o Roller chain is specified by pitch, width, and roller diameter. o Pitch is the center to center distance on the roller pins. ROLLER CHAIN NOMENCLATURE  ROLLER CHAIN NOMENCLATURE o Roller chain is made in several sizes, the most common American National Standards Institute(ANSI) standards being 40, 50, 60, and 80 o The first digit(s) indicate the pitch of the chain in eighths of an inch o The last digit being 0 for standard chain, 1 for lightweight chain, and 5 for bushed chain with no rollers. https://en.wikipedia.org/wiki/Roller_chain  ROLLER CHAIN NOMENCLATURE o Thus, a chain with half inch pitch would be a #40 while a #160 sprocket would have teeth spaced 2 inches apart, etc. 16 X 1/8” = 2 inches o Metric pitches are expressed in sixteenths of an inch; thus a metric #8 chain (08B-1) would be equivalent to an ANSI #40. o Most roller chain is made from plain carbon or alloy steel, but stainless steel is used in food processing machinery or other places where lubrication is a problem, and nylon or brass are occasionally seen for the same reason. o Source: https://en.wikipedia.org/wiki/Roller_chain  CHAIN SPROCKET NOMENCLATURE o A Plate Only o B Hub One Side o C Hub Both Sides o D Detachable Hubs  CHAIN SPROCKET NOMENCLATURE o Sprocket identification information is generally found stamped into the hub of a chain sprocket. The markings will generally consist of 2 digits followed by 2 or 3 letters, followed by 2 or 3 numbers, followed by a fraction.  Example 50BSS28 7/8 o In this case, the 50 refers to the chain pitch the sprocket is designed to function with. The BSS refers to a B style hub, made from Stainless Steel. The 28 references the number of teeth on the sprocket. Lastly, the 7/8 refers to the bore diameter of the sprocket. USE CAUTION AROUND CHAIN DRIVEN EQUIPMENT!!  APPLICATION o Moving product oMoving components  SILENT CHAIN o Silent chain uses an inverted tooth design and consists of a series of toothed link-plates assembled on pin connectors permitting smooth joint articulation. Generally used on prime movers rated below 50 horsepower.  SILENT CHAIN Silent chain is designated using the following nomenclature: example SC816 SC = ANSI standard silent chain First digit is pitch, in 1/8 inches Second and third digits represent the width in ¼ inch increments Therefore an SC816 is an ANSI standard silent chain with a pitch of 1 inch (8*1/8), and a width of 4 inches (16*1/4).  ROLLER CHAIN IDENTIFICATION o Roller chain guides ALIGNMENT  CHAIN INSPECTION o Elongation exceeding 3% chain should be replaced  Will not mesh with sprocket properly.  3% is.36” per foot of chain.  Do not insert new chain with old worn chain o Look for:  Wear on the side of sprocket teeth = misalignment  Wear on working faces of teeth = improper lubrication  Hook shaped teeth = replace sprocket  Running new chain in old sprockets will wear chain prematurely  CHAIN ALIGNMENT o INCLUDES PARALLEL SHAFT AND AXIAL SPROCKET ALIGNMENT. o MAKE SURE THE SHAFTS ARE PARALLEL AND LEVEL. o SPROCKET AXIAL IS VERIFIED BY PLACING A STRAIGHTEDGE ACROSS THE FACES OF THE SPROCKETS  Offset gap should be zero, but allowable offset is: #25, #35 = 1/64 in, #40, #50, #60 = 1/32 in, #80 = 3/64 in o Allowable out of parallelism is defined by:  Tolerance (in/ft) * 5.01803 *  CHAIN INSTALLATION o Place sprockets as close to the bearings as possible to minimize overhang. o Minimize axial float (do not eliminate) to accommodate thermal growth of the shaft when running. o Chain length calculation: Chain length (ft) = where o PD1 = pitch diameter of small sprocket o PD2 = pitch diameter of large sprocket o CD = center distance between shafts  CHAIN TENSION o Tension on a chain ‘by rule of thumb’ should be ¼ inch per 5 inches of distance tangentially between the large and small sprocket in a horizontal configuration, and roughly.12 inches per 5 inches of distance tangentially between the large and small sprocket in a vertical configuration. o https://www.youtube.com/watch?v=pjyxSGW8gyE o A chain which is too slack will produce unwanted vibration, and a chain tensioned too tight will produce faster wear on the parts.