Design Guide

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Design Guide 29 Development of Early Roller Chain As the industrial revolution gained pace, the need for higher performance chain ensured that the product did not stand still. A quick look at the 1880 patent would give the impression that there is no difference between it and modern chain. In concept, this is true. However, early chain performance was very much constrained by design knowledge, material sophistication, and production processes. For example, in order to achieve a close tolerance on round parts, Hans Technical Information Technical Renold also pioneered centerless grinding and, at one time, had a whole section devoted to grinding cold drawn bar to size before further processing. The shortcomings of available technology meant that, compared with modern chain, there were low strength to weight ratios, erratic pitch control, poor engagement Offset link chain, like conveyor chain, is intended to run characteristics, and a tendency toward point loading; only at low speeds, since the presence of an offset link causing high bearing pressures, wear, and failure. The plate will reduce fatigue life. This chain tends to be used ever-increasing number of applications for chain resulted in conveying applications where harsh environmental in a continuous refinement of our production processes conditions prevail, in mineral excavation, for example. and the introduction of heat treatment, improving Renold Chain to meet these new and arduous demands. Leaf chain is similar in construction to the old Galle chain, except that plates are interleaved in various configurations right across the width of the pin. This means that there Modern Chain is no way of providing sprocket engagement and the Today there is a very wide range of chain products available. chain can only be used to transmit force through suitably Some of these are special low-volume products, for example, anchored ends. Chains are guided around simple plain nuclear-waste-handling chain. Motorcycle chain and other pulleys. Perhaps the best example of the use of leaf chain high-volume products are an offshoot of one of the key is in the lifting mechanism of a forklift truck. groups shown below. This leaves the most important group of chain, the European At the top level of the chain groups, conveyor chain is and American series of transmission roller chain. The perhaps the most difficult to compartmentalize, since most European (from the British Standard) range grew out of types of chain can be used to convey. There is, however, a the early pioneering work of Hans Renold, as mentioned range of so-called conveyor chain products typified by previously, and the size of components through this range their long pitch, large roller diameter, and emphasis on therefore reflected a growing understanding of chain tensile strength rather than fatigue life. design and likely was influenced by the availability of stock material sizes. The American, or ANSI, range, which came later, has a clear mathematical theme, whereby the sizes of components are calculated in accordance with expressions now quoted in the ANSI standard B29.1. The ANSI range of chain is shadowed by a range of similar chains, heavy series, which use the side plate material from CHAIN FAMILY TREE the chain of the next highest size. This results in a range of chains with higher fatigue life but not necessarily higher tensile strength, since the pin diameters are unchanged. Roller Leaf Conveyor Chain Chain Chain Both European and ANSI ranges of chain are available in double pitch and rollerless chain forms. Double pitch is primarily another form of conveyor chain that uses the European American (BS) (ANSI) round parts from a standard chain, but has twice the pitch. Range Range Rollerless chain is simply roller chain without a roller and is also the only design configuration possible on very small

Standard Double Bush Standard Heavy pitch chain, such as 4mm and ANSI 25 or 1/4-inch pitch. Series Pitch Chain Series Series Rollerless chain is used for lightly loaded applications or those requiring only direct pull.

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29 Design Guide Modern chain has features that enable demanding Loads below the endurance limit will result in infinite fatigue applications to be tackled with ease. These include high life. The failure mode will then become wear related, which wear and fatigue resistance, as well as transmission is far safer, since a controlled monitor of chain extension efficiency of approximately 98 percent. can take place at suitable planned intervals. In practice, if a load ratio of tensile strength to maximum working load of Chain is also now manufactured in multiple strands joined 8:1 is chosen, then the endurance limit will not normally be together by a common pin, giving more scope for increased exceeded. Careful consideration of the expected maximum power transmission in restricted space. The range of working loads should be given since these are often much products — now available with alternative materials, special higher than the designer may think! It is also a requirement coatings, endless varieties of attachments, hollow bearing Technical Information Technical that any passenger lift applications are designed with a pins, and anti-backbend, to name just a few — give scope safety factor of not less than 10:1. for the widest portfolio of design solutions imaginable. Renold Jeffrey's experienced technical staff is available to In most applications, wear is the designed failure mode and consult with you as to which design solutions are the most therefore, some consideration of how a chain behaves in appropriate for your specific use. this mode are shown below. Together with improvements to factory-applied greases and Examination of the wear characteristics graph below better understanding of applications, designers can now shows that chain tends to wear in three distinct phases. specify transmission chain with confidence. The first phase, shown as “bedding in,” is a very rapid change in chain length associated with components Chain Performance adjusting to the loads imposed on them. The degree of Renold Jeffrey chain products that are dimensionally in this initial movement will line with the ISO standards far exceed the stated minimum depend to a large tensile strength requirements. However Renold does not extent on the quality Wear Characteristics consider breaking load to be a key indicator of performance Projected life of chain used — for 15,000 hours because it ignores the principal factors of wear and fatigue. example, good Bedding in. Adjust tension In these areas, Renold products are designed to produce the component fits, chain Initial wear best possible results and independent testing proves this. pre-loaded at

In this catalog, where the breaking load is quoted, it should manufacture, plates Steady state wear be noted that we are stating that the Renold product conforms assembled squarely, (%) Elongation

to the ANSI minimum standard. Independent test results etc. Renold Chain has 100 200 show that the minimum (many companies quote averages) many features that Elapsed Time (hours) breaking loads were far in excess of the ISO minimum. minimize the degree of bedding in. Where the quoted breaking load is not described as being the ANSI minimum, the product has no relevant ISO The second phase, shown as “initial wear,” might also be standard. In this case, the breaking loads quoted are the described as secondary bedding in. This is caused first minimum guaranteed. by the rapid abrasion of local high spots between the mating surfaces of the pin and bushing, and secondly, The performance of a chain is governed by a number of by displacement of material at the bushing ends. This is key factors. The tensile strength is the most obvious since explained more clearly by the inner link assembly diagram this is the means by which a chain installation is roughly shown, which demonstrates that in order to ensure good sized. However, since a chain is constructed from steel, fatigue life, the bushing and plate have a high degree of the yield strength of which is around 65 percent of the interference fit resulting in a tendency of the bushing ends ultimate tensile strength, any load above this limit will to collapse inwards slightly. This localized bulge will wear cause some permanent deformation to take place with rapidly until the pin bears equally along the length of the consequent rapid failure. bushing. Renold limits this effect by introducing special Reference to the s-n curve below shows that at loads below manufacturing techniques. Some manufacturers maintain this 65 percent line, finite life may be expected, and, at cylindricity by reducing the interference fit to a very low subsequent reductions level. This reduces fatigue performance.

s-n curve ZONE Failure in load, the expected Mode The final steady state of wear S A Overload life increases until the Breaking B Fatigue will continue at a very low rate Load A C Wear fatigue endurance limit until the chain needs renewal. is reached at around Permanent In a correctly designed and Deformation 65% B 8,000,000 operations. lubricated system, 15,000 hours LOAD

Endurance of continuous operation should C Limit 1 8.0x106 n be expected. Cycles to failure Tendency of bushing to collapse at assembly

216 www.renoldjeffrey.com • advancing chain technology sec_29.2_TI 11/19/0811:51AMPage217 elongation further. toreducetheallowable percentageof it isnecessary thesystembecome even higher, When thedemandsof Centerdistancesare greater thanrecommendedand • Perfect synchronization isrequired. • Asprocket inthesystemhas90teethormore. • Elongation shouldbelimitedto1percentwhen: up andjumpingthesprocket teeth. therecanbeproblems withthechain riding elongation, Above 2percent thechain. thenominallengthof of 2percent ELONGATION may amounttoaMAXIMUM of chain willbecomeelongated. thepinandbushing areerodedinsuch away that the of The hardenedlayers specific pressureonthesesurfaces. by thebearingareaand wear isprimarily determined The rate of thepinandbushing. between themating of weartakes placefromthefriction As alreadyshown, Wear Factors systemdesign. aspectof be animportant and mixed frictionstates andthat lubrication willtherefore pin/bushing combination isoperating betweenthestatic This meansthat the before comingtorestoncemore. engaging withthesprocket smallanglewhen through avery andaccelerate rapidly travel fromonesprocket totheother, no metal-to-metalcontact. thereis hydrodynamic duringwhich frictionoccurs speed, With acontinuing increaseinsurface material lossover time. These twoconditionsresultin is knownas“mixed friction.” This condition friction takes placewithsomesurfacecontact. lubricantisdrawn betweenthetwosurfacesand increase, Asthesurfacespeeds or noseparating lubrication layer. thetwobodiesareinterlocked withlittle of irregularities The reasonfor thisisbecausethesurface as static friction. known initialmovement, highatfriction isvery thepointof of thecoefficient twomating surfacesareincontact, where Itshowsthat with reference totheStribeck diagram below. The weartakes reasonwhy placeat allisdemonstrated not adjustable. Stribeck diagram Coefficientfriction Mixed of friction Boundary friction Boundary Static friction Hydrodynamic friction Rotational speed to each otherduring withrespect stationary these componentsare quickly berealized that itwill sprocket system, atwo- during onecycle of thebushing andpin of themating surfaces of weconsidertheaction If www.renoldjeffrey.com •advancing chaintechnology TNADISO606ANSIB29.1 STANDARD TRIPLE-STRAND CHAIN ISO606ANSIB29.1 STANDARD DOUBLE-STRAND CHAIN ISO606ANSIB29.1 STANDARD SINGLE-STRAND CHAIN Chain Types chain standardsaresummarized onpage218. The key roller standard. chain beproducedtoaformal demandsthat industry As withallengineeredproducts, URCTO sarayson usingthecorrect LUBRICATION -Asalreadyshown, • the chain, thelengthof CHAINLENGTH-The shorter • teethin NUMBEROFTEETH-The fewer thenumber of • NUMBEROFSPROCKETS -The moresprockets usedina • thehigher asystem, SPEED-The higherthespeedof • Wear dependsonthefollowing variables inadrive system: lubrication iscriticaltogivinggoodwearlife. thefasterweartakes place. operate, more frequently thebearingsinchain willhave to higher thewear. the articulation, thegreater thedegreeof a sprocket, themorefrequently thebearingsarticulate. drive system, soaccelerating wear. bearingarticulations, frequency of Design Guide 217 29 Technical Information sec_29.2_TI 11/19/08 11:51 AM Page 218

29 Design Guide International Standards ANSI chain is also available in heavy-duty options with European Standard thicker plates (H) and through-hardened pins (V). An ANSI ISO 606 and DIN 8187 cover chains manufactured to the heavy-duty chain would be specified using these suffixes: above standards. These standards cover three versions: i.e. ANSI 140-2HV Double-strand, thick plates, • Single-Strand through hardened pin • Double-Strand ANSI 80H Single-strand, thick plates • Triple-Strand The range of pitch sizes can vary from 4mm (0.158 inch) Range of Application

Technical Information Technical to 114.3mm (4.500 inch). The roller chain market worldwide is divided between these two chain standards, based on the economic and historical They are characterized by a large pin diameter, especially influences within their regions. for the larger pitch sizes. This results in better wear resistance due to the greater bearing area. • American standard chain is used primarily in the USA, Canada, Australia, Japan, and some Asiatic countries. The ISO standard has a simple form of part numbering, for example, 1/2-inch pitch double-strand chain would be 08B-2. • European standard chains dominate in Europe, the British Commonwealth, Africa, and Asian countries with a • The first two digits are the pitch size in 1/16ths of an strong British historical involvement. inch, therefore 08 = 8/16 or 1/2 inch. In Europe, approximately 85 percent of the total market • The letter B indicates European Standard. uses European standard chain. The remaining 15 percent • The suffix “2” indicates the number of strands in the are American standard chains found on: chain, in this case a double-strand chain. • Machinery imported from countries where American standard chain dominates.

American Standard • Machinery manufactured in Europe under license from American standard chains are covered by ISO 606, ANSI American-dominated markets. B29.1, and DIN 8188. Eight versions are covered. • Single-Strand Chain Not Conforming to ISO Standards • Double-Strand There are also Renold Jeffrey manufacturing standards for • Triple-Strand special or engineered chain, which can be categorized as • Multiple-Strand (4-, 5-, 6-, 8-, and 10-strand) follows: The pitch sizes covered by this standard are 1/4 to 3 inch 1. HIGHER BREAKING-LOAD CHAIN – This chain usually pitch. has plates that undergo a special treatment, has thicker American standard chains have a smaller pin diameter side plate material and/or pin diameters that slightly than their European standard equivalent. Wear resistance deviate from the standards. is therefore reduced when compared with European 2. SPECIAL DIMENSIONS – Some chains can be a mixture standard chains, with one exception, 5/8-inch pitch. In this of American and European standard dimensions or have case the pin and bushing diameter is larger in American inner widths and roller diameters that vary, such as in standard chain. motorcycle chains. American standard chains are normally referred to under 3. APPLICATIONAL NEEDS – Special or engineered chain the ANSI standard numbering system, for example, a 1/2- is manufactured for specific applications, examples inch pitch double-strand chain would be ANSI 40-2. being: The ANSI numbering system works as follows: • Stainless steel chain • The first number is the pitch size in 1/8ths of an inch, • Zinc- or nickel-plated chain i.e., 4/8 = 1/2-inch pitch. • Chain with plastic lubricating bushings • The second number indicates that the chain is a roller chain (0 = roller chain). A “5” instead of a “0” indicates a • Chains with hollow bearing pins rollerless chain. • Chain that can bend sideways, (Sidebow chain) • The suffix, as with European standard chain, refers In applications requiring a special or engineered chain, to the number of strands in the chain, i.e., 2 = double- contact our technical sales staff for more information. strand chain.

218 www.renoldjeffrey.com • advancing chain technology sec_29.2_TI 11/19/0811:51AMPage219 olrLa hisfrOeha oss—B92M— — — DIN8152 B29.24M B29.8M DIN8182 — — APISpec7F B29.1M 4347 — 9633 10190 B29.1M DIN8181 3512 DIN8154 DIN8187 606 B29.3M Roller LoadChainsfor Overhead Hoists andSheaves Clevises, Chain, Leaf — B29.1M Lifting ChainTypes 1275 LinkChainandSprockets Offset 1395 Motorcycle Chains 606 Cycle Chains Oilfield ChainandSprockets Double Pitch Roller ChainandSprockets Pitch Rollerless ChainsandSprockets Short Pitch Roller ChainandSprockets Short Roller Chain Types www.renoldjeffrey.com •advancing chaintechnology S NIOTHER ANSI ISO OTHER ANSI ISO Standards Reference Guide DIN8188 Design Guide 219 29 Technical Information sec_29.2_TI 11/19/0811:51AMPage220 29 Technical Information 220 Design Guide for consultation. Renold representatives Jeffrey areavailable processing. andwood rock drilling, baking, mining, processing, environmentssuccessfully insuch harsh as chemical Chainisused temperature. including extremes of environmental conditions, awidevariety of is tolerantof chain Since therearenoelastomericcomponentsinvolved, diameter drums. chain sprocket rimscanbefittedto large “necklace” Segmentaltoothor orweightsuspension. hoisting, counterbalancing, gearing, orexternal internal motions, cam racks, including reciprocation, devices, variety of Itcanbeusedfor awide from acommondrive point. adaptability isnotlimitedtodrivingoneormoreshafts Its centerdistanceorlayout. almost any configuration of One chain candrive several shaftssimultaneously andin chain inthestatic condition. shaft bearingssincenopre-loadisrequiredtotensionthe Roller chain minimizes loadsonthedrive motoranddriven entailsprocketnormally orbearingremoval. theprocedureissimpleanddoesnot replace achain, to itbecomesnecessary afterlengthy service, When, wear. assistsinreducing which teeth, takes placeover anumber of addition, chain anoilfilminthe of plusthecushioningeffect and this, inherentelasticity, degreeof Roller chain hasacertain double pitch chain comesintoitsown. category, Inthislater the chain traverses aconsiderable span. so that thesprocket teethjustclear each otherorsothat Drives canbeengineered compact installation envelope. inavery inches (50mm)tomorethan29feet (9meters) Center distancesbetweenshaftscanrangefromabouttwo proved consistently quietandreliable. rollerchain has isalsorequired, efficiency peak loadwhen highspeedand Underconditionsof printing machinery. andpackaging and automobile andmarinecamshafts, such asthoseto is essentialonsynchronized drives, which It provides anaccurate pitch-by-pitch positive drive, drivingmedium. non-slip, apositive, Roller chain offers closewith teethgroundtovery tolerances. thehigheststandard, isequaledonly of by gears installation, lubrication and chain conditionsof drive underthecorrect achieved by astandardstock efficiency, This highlevel of between98.4and98.9percent. of efficiency Tests have shownchain tohave an energy iswasted. little very Asaresult, insidethebushing. pin articulation bearing independentof thebushings, rotate ontheoutsideof eliminatedsprocket becausetherollers teethisvirtually Any and frictionbetweenthechain rollers power. flow of efficient asmooth, permitting with excellent jointarticulation, Steel transmissionrollerchain ismadetoclose tolerances Advantages ofChainDrives ons rvdsgo hc bobn rpris In provides goodshock absorbingproperties. joints, the loaddistribution betweenachain andsprocket www.renoldjeffrey.com •advancing chaintechnology Notappropriate = X Poor = Good C = ExcellentB = A Summary of Advantages transmission/liftingmedia. different Shown belowisasimpletable comparingthemeritsof the environment. to also totally recyclable effects andcauses noharmful Itis accordance withISOStandardsallover theworld. Chain isahighly standardized productavailable in systems for aircraft. hoists for controlrodsinnuclear andcontrol reactors their expected for performance applications such as chains canbeselectedon and longlife areessential, Where completereliability from eitherfatigue orwear. canbereasonably expectedhours withoutchain failure 15,000 alife of and properly installedandmaintained, Provided that achain drive isselectedcorrectly sprocket. by centerdistanceadjustmentorby anadjustable idler isgradualandcanbeaccommodated normally which agebeingelongation duetowear, the only evidence of time; Roller chain doesnotdeteriorate withthepassageof hp at 300rpm. triple-strandchain canachieve 4,288 matched strandsof four Beyond this, to transmitup697hpat 550rpm. Roller chain drives areavailable for ratios upto9:1and These attachments aredetailedinthiscatalog. mechanisms. mechanical handlingequipmentandtheoperation of allowittobeusedfor which etc., extended bearingpins, Roller chain canalsobefittedwithlinkplate attachments, tnadzdCBB C B B B C B C C C A C B Environment X Standardized maintenance B B Ease of B B Power range C Adaptations C X Oil resistant X CHAIN Chemical resistant Heat resistant BELT C A A Multiple drives No pre-load ROPE Wear resistance GEARS Elasticity Center distance Positive drive Efficiency FEATURES AA A AA A A CC AA XB A CB A C C C BA A B A A A A A A A A A A A sec_29.2_TI 11/19/08 11:51 AM Page 221

Design Guide 29 Chain Selection insignificant for most applications as the number of teeth in the driver sprocket exceeds 19. The notes given below are general recommendations and should be followed in the selection and installation of a The effect of this cyclic variation can be shown in the chain drive, in order that satisfactory performance and extreme case of a driver sprocket with the absolute drive life may be ensured. minimum number of teeth, i.e. three. In this instance, for each revolution of the sprocket, the chain is subjected to a three-phase cycle; each phase being associated with Chain Pitch the engagement of a single tooth. As the tooth comes into The Quick Selector Chart (page 234) gives the alternative

engagement, for a sixth of a revolution the effective distance, Information Technical sizes of chains that may be used to transmit a load at a or driving radius, from the sprocket center to the chain is given speed. The smallest pitch of a single-strand chain gradually doubled; for the remaining sixth of a revolution, should be used, as this normally results in the most it falls back to its original economical drive. If the single-strand chain does not satisfy position. Thus, as the linear the requirements dictated by space limitations, high speed, speed of the chain is quietness, or smoothness of running, then consider a directly related to the smaller pitch of double-strand or triple-strand chain. effective driving radius of When the power requirement at a given speed is beyond the driver sprocket, the the capacity of a single strand of chain, then the use of chain speed fluctuates by multi-strand drives permits higher powers to be transmitted. 50 percent six times during each revolution of the driver These drives can also be made up from multiples of sprocket. matched single-, double-, or triple-strand ISO chains, or in the case of ANSI chain, multi-strand chain of up to 10 As the graph below shows, the percentage of cyclic strands are available. speed variation decreases rapidly as more teeth are added. With a driver sprocket of 19 teeth, therefore, this Please consult our technical staff for further information. cyclic speed variation is negligible; hence we recommend that driver sprockets used in normal application drives Maximum Operating Speeds running at medium to maximum speeds should not have For normal industrial drives, experience has established less than 19 teeth. a maximum sprocket speed for each pitch of chain. These There are, however, applications where space saving is a speeds, which relate to driver sprockets having 17 to 25 vital design requirement and the speed/power conditions teeth inclusive, are given in the graph below; they are are such that the smaller numbers of teeth (i.e., less than 17) applicable only if the method of lubrication provided is give acceptable in line with recommendations. performance, so that a 50

40 compact, satisfactory

Polygonal Effect 30 drive is achieved, i.e., Four important advantages of a chain drive are dependent 20 office machinery, hand directly upon the number of teeth in the driver sprocket. 10 operated drives, Cyclic Speed Variation % Cyclic Speed Variation 0 5 10152025 mechanisms, etc. The advantages are smooth uniform flow of power, No. of Teeth quietness of operation, high efficiency, and long life; the reason for their dependence being that chain forms a The limiting conditions with steady loading for using small polygon on the sprocket. Thus, when the sprocket speed numbers of teeth are: is constant, the chain speed (due to the many- Number Percentage of Percentage of Maximum Operating Speeds sided shape of its path 6000 of Maximum Rated Maximum Rated around the teeth) is Teeth Speed Power 5000 subject to a regular 4000 cyclic variation. This 11 20 30 3000 cyclic variation becomes 2000 Speed (rpm) less marked as the 13 30 40 1000 path of the chain tends 0 10 20 30 40 50 60 70 80 towards a true circle Chain Pitch (mm) 15 50 60 and, in fact, becomes 17 80 90

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29 Design Guide Sprocket and Chain Compatibility Most drives have an even number of chain pitches and, Recommended center distances for drives are: by using a driver sprocket with an odd number of teeth, Pitch inch 3/8 1/2 5/8 3/4 1 1-1/4 uniform wear distribution over both chain and sprocket mm 9.525 12.70 15.87 19.05 25.40 31.75 teeth is ensured. Even numbers of teeth for both the driver Center inch 17.715 23.622 29.528 35.433 39.370 47.244 and driven sprockets can be used, but wear distribution Distance mm 450 600 750 900 1000 1200 on both the sprocket teeth and the chain is poor. Pitch inch 1-1/2 1-3/4 2 2-1/2 3 mm 38.10 44.45 50.80 63.50 76.20

Technical Information Technical Number of Teeth Center inch 53.150 59.055 66.929 70.866 78.740 The maximum number of teeth in any driven sprocket should Distance mm 1350 1500 1700 1800 2000 not exceed 114. This limitation is due to the fact that for a given elongation of chain due to wear, the working pitch diameter of the chain on the sprocket increases in relation Lie of Drive to the nominal pitch diameter, i.e., the chain assumes a Drives may be arranged to run horizontally, inclined, or higher position on the sprocket tooth. The allowable safe vertically. In general, the loaded strand of the chain may chain wear is considered to be in the order of 2 percent be uppermost or lowermost, as desired. Where the lie of elongation over nominal length. the drive is vertical, or nearly so, it is preferable for the A simple formula for determining how much chain driver sprocket to be above the driven sprocket; however, elongation a sprocket can accommodate is even with a drive of vertical lie, it is quite feasible for the 200 driver sprocket to be lowermost, provided care is taken N that correct chain adjustment is maintained at all times. expressed as a percentage where N is the number of teeth on the largest sprocket in the drive system. It is good practice to have the sum of teeth not less than 50, where both the driver and driven sprockets are operated CENTERS by the same chain, i.e., on a 1:1 ratio drive, both sprockets The center distance should have 25 teeth each. between the axis of two shafts or sprockets Center Distance For optimum wear life, center distance between two C sprockets should normally be within the range 30 to 50 times the chain pitch. On drive proposals with center C distances of less than 30 pitches or greater than 6.6 feet (2 m), discuss the drive details with our technical staff. ANGLE The minimum center distance The lie of the drive is sometimes governed by the is given by the angle amount of chain lap on the formed by the line

driver sprocket. Our normal through the shaft J recommendation in this centers and a circumstance is not less than horizontal line 6 teeth in engagement with the chain. Minimum 6 Teeth ROTATION

The center distance is also governed by the desirability of Viewed along the Z2 using a chain with an even number of pitches to avoid the axis of the driven use of an offset link, a practice that is not recommended shaft, the rotation Z1 Z2

except in special circumstances. can be clockwise Z1 or anti-clockwise For a drive in the horizontal plane, the shortest center distance possible should be used consonant with recommended chain lap on the driver sprocket.

222 www.renoldjeffrey.com • advancing chain technology sec_29.2_TI 11/19/0811:51AMPage223 eeto fpossibledrive layouts isshown below. A selectionof depends onthelayout. driven sprockets inany onedrive permissible number of The thechain. sprockets facesof togearindifferent thedrivenin thesameoroppositedirectionsby arranging individual shaftsinthesamedrive canbemadetorotate rollerchains togearoneitherface, due totheabilityof shaftsand One chain canbeusedtodrive anumber of Drive Layout DRIVES WITHVARIABLE SHAFTPOSITIONS exceed 197feet perminute. thechain speeddoesnot and where cannotbeemployed idlers or supporting For countershafts applications where guides: Or supporting to 492feet perminute. For slowandmediumchain speedapplications up idlers: Or supporting countershafts: Could incorporate LONGCENTERS DRIVES WITH ABNORMALLY chain multiplied by 30to50. CENTERS -Pitch of 27teethormore. for sprocketspermissible of 90° Minimum of CHAIN LAP-Recommended 120°. Floating andfloatingidler countershaft Z Z 1 2 Z 1 Z 1 Z 1 JJ J J Z Z 1 2 www.renoldjeffrey.com •advancing chaintechnology Z Z Z 2 2 2 mohetyadei fchain. andexit of smooth entry toensure chain strands withgenerous“lead-in” useguidestripstosupport arelong, When centers Two mounted: shaftsvertically DRIVES HORIZONTAL driven sprockets. The idlerisusedtoensureadequate chain laponthe but reducedtoothcontact: Eight shaftsrotatedby asinglechain withhighefficiency motor powertoallowfor thisreducedefficiency. thisnature toincreasethecalculated in applications of Itisnecessary drives involved. withthenumber of vary theoverall will efficiency drives(as inlive areinterconnected rollerconveyors), aseriesof if However, 98%. asingle-stagedrive isapproximately of The efficiency Five sprockets coupledby four simpledrives: according todrive characteristics. driven shaftswillvary numberThe of permissible MULTI-SHAFT DRIVES CENTERS - Shortest possible CENTERS -Shortest 27teethormore. for sprockets permissible of 90° Minimum of CHAIN LAP-Recommended 120°. mounted: shaftsvertically Three Z Z 1 2 J 12 drives overall =80% efficiency 8 drives overall =87% efficiency 4 drives overall =94% efficiency Z 2 Z 2 Z 2 Z Z 1 1 Design Guide Z 2 Z 2 Z 1 Plan Plan Z 2 223 29 Technical Information sec_29.2_TI 11/19/0811:51AMPage224 29 Technical Information 224 Design Guide one ost aho theselectioncurves. rounded topstoeach of comesintoplayroller fatigue curve andaccountsfor the thebush and theselines, of Attheintersection speeds. lubrication break-downat high very occur duetoboundary pingalling will However, recommendation isexceeded. themaximum power likely tobeplate fatigue if thefailuremodeis Atlowerspeeds, three simplelines. from itisconstructed however, glance, complicated at first (page234)may appear The Quick SelectorChart Quick SelectorChartConstruction

POWER RATING CHART CONSTRUCTION

Link Plate F

atigue Pin Galling SPEED www.renoldjeffrey.com •advancing chaintechnology Bush &Roller fatigue given inthisguide. without reference totheotherchain selectionmethods various bearingpressuresbut shouldnotbeused of theimplications The following table gives anindication of thisguide. designer data at theendof Bearing areasfor standardchains arequotedinthe obtained by loadby dividingtheworking thebearingarea. This pressureisknownasthebearingand pinandbush). between thekey mating surfaces(i.e., pressure isthemagnitudeof chain performance indicator of useful very a However, inthisguide. been addressedearlier has dependsonmany which factors, wear, The subjectof timeismostlikely tobewear. over longperiodof avery failure themodeof selected, When achain hasbeencorrectly Bearing Pressures figures shouldbeusedasaguideonly. The above There issomevariation betweenchains. Note: maximum allowable speed High velocity morethan80%of maximum allowable speed Medium velocity 60to80%of maximum allowable speed Slow velocity upto60%of

BEARING PRESSURE (Lbs/in2 ) 12,000 3,000 6,000 9,000

LWMDU HIGH MEDIUM SLOW SINGLE-STRAND CHAIN VELOCITY (Ft/min)

MULTI-STRAND

SINGLE-STRAND

MULTI-STRAND expectancy Good life Reduced life Contact Renold Jeffrey SINGLE-STRAND

MULTI-STRAND sec_29.2_TI 11/19/08 11:51 AM Page 225

Design Guide 29 Lifting Applications This section covers applications such as lifting and moving, where the loads involved are generally static. Obviously, Applications dynamic loads are also involved in most applications and the designer needs to take due consideration of these. The machinery designer should also refer to DTI Publication INDY J1898 40M, which summarizes legislation in place from January 1, 1993 and January 1, 1995 regarding machinery product standards. Technical Information Technical Chain for lifting applications falls into two main categories: • Leaf Chain • Bush/Roller Chain 1. Machine Tools - Planers, 2. Fork Lift Trucks, Lifts, Leaf Chain Drills, Milling Heads, Hoists. Machine Centers. Leaf chain is generally used for load-balancing lifting applications as illustrated below. They must be anchored at either end since there is no means of geared engagement in the chain itself.

Safety Factors A safety factor of 7:1 is normal for steady-duty reciprocating motion, i.e., fork lift trucks. For medium shock loads, the ratio is 9:1 and for heavy shock loads, 11:1.

Operating Speed 3. Counterweight Balances - Applications should not exceed a maximum chain speed of Jacks, Doors, Gates, etc. 98 feet/min (30 meters/min).

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29 Design Guide Roller and Rollerless Chains In order to accommodate these higher fatigue-inducing loads, material for inner and outer plates is increased in Roller and rollerless chains can be used for lifting and thickness by approximately 20 percent. moving purposes and have the advantage over leaf chain in that they may be geared into a suitable driving sprocket. This modification does not improve the tensile strength Roller chain has a better wear resistance than leaf chain since the pin then becomes the weakest component. and may be used at higher speeds. However, heavy-duty chains with higher tensile strength are available. These chains feature through-hardened instead Safety Factors of case-hardened pins, however, wear performance is Applications vary widely in the nature of loads applied, reduced due to the lower pin hardness.

Technical Information Technical therefore, apply safety factors to allow for some degree Renold ANSI H and HV chains are available as follows: of abuse. H Series - Thicker plates A factor of safety of 8:1 in non-passenger applications HV Series - Thicker plates and through-hardened pins A factor of safety of 10:1 in passenger applications The H and HV chains are not suitable for high-speed Lower safety factors may not be used in passenger drive applications. applications. In non-passenger applications and after careful consideration of maximum loads and health and It should also be noted that single-strand chains of standard, safety implications, lower safety factors may be used. See H, or HV designs all have identical gearing dimensions and the section “Influences on Chain Life” below or contact therefore can operate on the same sprockets as standard Renold Jeffrey technical staff. chains. The thicker plates require a larger chain track, and it may be desirable to use sprockets with heat-treated teeth. Multi-strand chain requires an increased transverse pitch of Operating Speeds the teeth but other gearing dimensions are the same. Applications should not normally exceed a maximum chain speed of 148 feet/min (45 meters/min). For higher speeds, consider selection as if the chain were in a power drive Influences on Chain Life application converting the chain load to horsepower using Factors of Safety the following formula: All Renold Chain is specified by its minimum tensile POWER (HP) = FV strength. To obtain a design working load it is necessary 33,000 to apply a “FACTOR OF SAFETY” to the breaking load. However, before considering this, the following points Where: F = Lbs. should be noted: V = Ft./min. • Most chain side plates are manufactured from low- to Then apply service factors as shown in Step 2 of medium-carbon steel and are sized to ensure they have Roller Drive Chain Selection on page 231. adequate strength and ductility to resist shock loading. • These steels have yield strengths of approximately Calculate equivalent RPM by using the smallest sprocket 65 percent of their ultimate tensile strength. This means in the system and the following formula: that if chains are subjected to loads of greater than this, SPEED = 12V depending upon the material used in the side plates, PZ then permanent pitch extension will occur. Where: P = Chain pitch (in.) • Most applications are subjected to intermittent dynamic Z = No of teeth in small sprocket loads well in excess of the maximum static load and V = Ft./min. usually greater than the designer’s estimate. Select lubrication methods. • Motors, for example, are capable of up to 200 percent full load torque output for a short period. ANSI H and HV Series As a result, chain confidently selected with a factor of Drive chain is also available in heavy-duty versions of the safety of 8:1 on breaking load is, in effect, operating with ANSI standard range of chain. a factor of safety of around 5:1 on yield and much less than this when the instantaneous overload on the drive is These chains are suitable where frequent load reversals considered. are involved. Typical applications are in primary industries such as mining, quarrying, rock drilling, forestry, and construction machinery.

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Design Guide 29 Important Note Safety Factors For factors of 5:1, the resulting bearing pressure is 50 12 percent higher than recommended. Chain working under Harsh Environments 11 these conditions will wear prematurely, despite the type of 10 Passenger Lifts lubrication regime used. 9 Transmission Harsh Environments 8 Critical Safety In anything other than a clean and well-lubricated 7 High-Cycle Lifting environment, the factor of safety should be adjusted if some detriment to the working life of the chain is to be 6 Low-Cycle Lifting avoided. Low temperatures will also decrease working Information Technical 5 life, especially if shock loads are involved. 4 3

Axial breaking force/max working load Axial breaking force/max Not Normally Used 2 The following tables give a general guide to the appropriate 1 safety factors for different applications for a target life of approximately 8,000,000 cycles. Cleanliness A further consideration when applying a factor of safety Lubrication Clean Moderately Clean Dirty/Abrasive to a chain application is the required chain life. Regular 8 10 12 In a properly maintained application, normal service life Occasional 10 12 14 is expected to be approximately 8,000,000 cycles or None 12 12 14 15,000 hours, whichever comes first. Wear will be the Temperature (ºF) usual mode of failure. Lubrication +50 to 300 300 to 390 390 to 570 In applications where low factors of safety are required, Regular 8 10 12 the service life will be reduced accordingly. Occasional 10 12 14 None 12 12 14 The maximum working load is obtained by dividing the chain minimum tensile strength by the factor of safety. Temperature Load Regime (ºF) Smooth Moderate Shocks Heavy Shocks The table below gives a rough indication of life for various +50 to 300 8 11 15 factors of safety. 32 to 50 10 15 19 -5 to 32 12 20 25 Factor -40 to –5 15 25 33 Cycles Type of Single-strand Multi-strand Maximum Application Chain Extension 5.0 6.0 1,000,000 Dynamic load When designing lifting applications, it can be useful to 6.0 7.2 2,000,000 does not exceed working load know how much a chain will extend under a given load. 8.0 8.0 8,000,000 Dynamic loads The approximate elongation of a chain under a given load can occasionally can be measured by using the following formulas. exceed working load by 20% -6 • Single-strand Chain (1.00) .10 .L L = .F 1 10.0 10.0 8,000,000 All passenger lifts p 2

(6.70).10-7 .L • Double-strand Chain L = .F 1 p 2 It should be noted that at factors below 8:1, bearing pressures increase above the maximum recommended. As • Triple-strand Chain (5.00) .10-7 .L L = .F 1 a result, increased wear will arise unless special attention is p 2 taken with lubrication, i.e.: Where: • More frequent lubrication L = Change in chain length (in.) • Higher-performance lubricants L = Original length of the chain (in.) • Better methods of applying lubrication P = Pitch of the chain (in.) F = Average load in the chain (lbs.) It is uncertain to what extent such lubrication may slow 1 the increased wear rate.

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29 Design Guide Matching of Chain Long chains are made in sections, each section being numbered on end links. Sections should be joined so that Any application in which two or more strands of drive chain end links with similar numbers are connected. When chains are required to operate side by side in a common drive or are to run in sets of two or more strands, each strand is conveying arrangement may involve the need for either stamped on end links of each section with a letter, in pairing or matching. Such applications generally fall into addition to being numbered. Correct consecutive sections one of the following categories : for each strand must be identified from the end links and Length Matching for Conveying and Similar Applications joined up as indicated. When length matching of drive chain is necessary, it is By these means, the actual length of any intermediate Technical Information Technical dealt with as follows: portion of one strand (as measured from any one pitch • The chains are accurately measured in handling lengths point to any other) will correspond closely with that of the between 10 ft. and 27 ft. (3m to 8m), as appropriate, and transversely equivalent portion on the other strands, generally then selected to provide a two-or-more-strand drive within 0.002 inches (0.05mm), depending on the chain having overall length uniformity within close limits. Such pitch size. length uniformity will not necessarily apply to any intermediate sections along the chains, although actual Pitch Matching Attachment Chains length of all intermediate sections, both along and across (when attachments are fit to chains) the drive, will not vary more than our normal manufacturing With the sole exception of extended bearing pins, it is not limits. However, adapted drive chains are usually possible to match the pitch of holes in attachments manufactured to specific orders which are generally themselves to within very fine limits. This is due to the completed in one production run, so it is reasonable to additional tolerances that arise with bending, holing, etc. assume that length differences of intermediate sections will be small. Color Coding For customers who wish to match their chains, perhaps in • Chains are supplied in sets that are uniform in overall order to fit special attachments, Renold color codes short length within reasonably fine limits and will be within our lengths of chain within specified tolerance bands. These normal manufacturing limits. It should be noted that will normally be RED, YELLOW, or GREEN paint marks to chain sets supplied for different orders at different times indicate lower, middle, and upper thirds of the tolerance may not have exactly the same lengths to those supplied band. For even finer tolerance bands, additional colors can originally, but will vary by no more than our normal be used, but normally a maximum of five colors is more tolerance of 0.0%, +0.15 percent. than adequate.

Pitch Matching Drive Chains Color Tolerance Pitch-matched chains are built from shorter subsections RED 0.05% (usually about 1 to 3 feet or 300 to 600mm lengths), which YELLOW 0.10% are first measured and then graded for length. All GREEN 0.15% subsections in each grade are of closely similar length and BLUE For finer those forming any one group across the set of chains are WHITE tolerances selected from the same length grade.

The requisite number of groups are then connected to To Measure Chain Wear form a pitch-matched set of chains, or alternatively, if this is A direct measure of chain wear is the extension in excess too long for convenient handling, a set of handling sections of the nominal length of the chain. Chain wear can for the customer to assemble as a final set of pitch-matched therefore be ascertained by length measurement in line chain. Suitable tags are fixed to the chains to ensure they with the instructions given below. are connected together in the correct sequence. • Lay the chain, which should terminate at both ends with an inner link, on a flat surface, and, after anchoring it at Identification of Handling Lengths one end, attach to the other end a turnbuckle and a Handling Handling Handling spring balance suitably anchored. Length 1 Length 2 Length 3 • Apply a tension load by means of the turnbuckle A Strand A-A1 A1-A2 A2-A3 amounting to: B Strand B-B1 B1-B2 B2-B3 C Strand C-C1 C1-C2 C2-C3 Single-Strand Chain (25.4 x P)2 x .173 lbs Double-Strand Chain (25.4 x P)2 x .351 lbs Triple-Strand Chain (25.4 x P)2 x .524 lbs Where P is the pitch in inches.

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Design Guide 29 In the case of double-pitch chains (i.e., chains having the Chain same breaking load and twice the pitch), apply measuring Chain repair should not be necessary. A correctly selected loads as for the equivalent short-pitch chains. and maintained chain should gradually wear out over a period of time (approximately 15,000 hours), but it should As an alternative, the chain may be hung vertically and the not fail. Please refer to the Installation and Maintenance equivalent weight attached to the lower end. section of this catalog, which gives an indication of how M to determine the service life remaining. If a drive chain sustains damage due to an overload, jam-up, or by riding over the sprocket teeth, it should be

carefully removed from the drive and given a thorough Information Technical visual examination. Remove the lubricating grease and oil to make the job easier. • Measure length ‘M’ (see diagram above) in inches from which the percentage extension can be obtained from Depending on the damage, it may be practical to effect the following formula: temporary repairs using replacement links. It is not, however, a guarantee that the chain has not been over- Percentage Extension = M - (N x P) x 100 stressed and so made vulnerable to a future failure. The N x P best policy, therefore, is to remove the source of trouble Where N = Number of pitches measured and fit a new chain. This should be done for the following P = Pitch reasons. • As a general rule, the useful life of a chain is terminated 1. The cost of downtime to the system or machine can and the chain should be replaced when extension often outweigh the cost of replacing the chain. reaches 2 percent (1 percent in the case of double- 2. A new or used portion of chain or joints assembled into pitch chains). For drives with no provision for adjustment, the failed chain will cause whipping and load pulsation. the rejection limit is lower, dependent upon the speed This will likely produce rapid failure of the chain and will and layout. A usual figure is between 0.7 and 1.0 accelerate wear in both the chain and its sprockets. percent extension. If a chain has failed two or more times, it is certain the chain will fail again in time. If no replacement is immediately Chain Wear Guide available, repair the chain, but replace it at the earliest A simple-to-use chain wear guide is available from opportunity. Renold Jeffrey for most popular sizes of chain pitch. Please contact your sales office for details. Chain Adjustment To obtain full chain life, some form of chain adjustment Repair and Replacement must be provided, preferably by moving one of the shafts. Sprockets If shaft movement is not possible, an adjustable idler Examination of both flanks will give an indication of the sprocket engaging with the unloaded strand of the chain is amount of wear that has occurred. Under normal recommended. Generally the idler should have the same circumstances, this will be evident as a polished worn number of teeth as the driver sprocket and care should be strip around the pitch circle diameter of the sprocket tooth. taken to ensure the speed does not exceed the maximum shown in the Quick Selector Chart (see page 234). If the depth of this wear “X” has reached an amount equal to 10 percent of the “Y” dimension, steps should be taken The chain should be adjusted regularly so that, with one to replace the sprocket. Running new chain on sprockets strand tight, the slack strand can be moved a distance having this amount of tooth wear will cause rapid chain wear. “A” at the midpoint (see diagram below). To cater for any eccentricities of mounting, the adjustment of the chain Depth should be tried through a complete revolution of the large of wear Y sprocket. X = 10 X PCD PCD A = Total movement C = Horizontal center distance

Y Total movement “A” (in.) = C (in.) K Where K = 25 for smooth drives It should be noted that in normal operating conditions, with 50 for shock drives correct lubrication the amount of wear “X” will not occur until several chains have been used. For vertical drives please consult the Installation and Maintenance section of this catalog, which gives more details on chain adjustment.