Conveyor Chain - Designer Guide
SECTION 4CONVEYOR CHAIN DESIGNER GUIDE66engineering excellence www.renold.com
Designer GuideIntroductionSelecting the right chain for a given application is essential toobtain long service life. This guide has been developed for usewith Renold conveyor chain to help in specifying the right chainand lubrication for your conveyor system. The significance of theRenold conveyor chain design is emphasised, followed byguidance on selection procedure. Detailed descriptions are givenof the various methods of application in a variety of mechanicalhandling problems and under widely varying conditions. Thesupporting material includes various reference tables andstatistics.Fig. 1From the pyramids to the railway revolution, muscle-power of menand animals has moved goods and materials, but throughouthistory, machines, however primitive, have played some part,becoming more and more versatile.From the foregoing, it will be seen that a length of chain is aseries of plain journal bearings free to articulate in one plane.When a chain articulates under load the friction between pin andbush, whilst inherently low because of the smooth finish on thecomponents, will tend to turn the bush in the inner plates andsimilarly the bearing pin in the outer plate. To prevent this thebush and pin are force fitted into the chain plates. Close limits ofaccuracy are applied to the diameters of plate holes, bushesand bearing pins, resulting in high torsional security and rigidityof the mating components. Similar standards of accuracy applyto the pitch of the holes in the chain plates.Within the immediate past, mechanical handling has emerged asa manufacturing industry in its own right, of considerable size andwith countless applications. This is a consequence of itscoverage, which now ranges from the simplest store conveyorsystem to the largest flow line production layouts, and alsoincludes the movement of personnel by lifts, escalators andplatforms.Amongst the most widely used types of handling equipment areconveyors, elevators and similar assemblies. These can takemany forms, employing as their basic moving medium bothmetallic and non-metallic components or a mixture of the two.For the great majority of applications Renold conveyor chain in itsmany variations, when fitted with suitable attachments, provides ahighly efficient propulsion and/or carrying medium, having manyadvantages over other types. Roller chain has been employed asan efficient means of transmitting power since it was invented byHans Renold in 1880. Later the principle was applied to conveyorchain giving the same advantages of precision, heat-treatedcomponents to resist wear, high strength to weight ratio and highmechanical efficiency.Renold conveyor chain is made up of a series of inner and outerlinks. Each link comprises components manufactured frommaterials best suited to their function in the chain; the variousparts are shown in Figure 1. An inner link consists of a pair ofinner plates which are pressed onto cylindrical bushes, whilst oneach bush a free fitting roller is normally assembled. Each outerlink has a pair of outer plates which are pressed onto bearingpins and the ends of the pins are then rivetted over the plate.4To ensure optimum wear life the pin and bush are hardened. Thebush outside diameter is hardened to contend with the loadcarrying pressure and gearing action, both of which are impartedby the chain rollers. Chain roller material and diameter can bevaried and are selected to suit applicational conditions; guidancein roller selection is given on page 73. Materials used in chainmanufacture conform to closely controlled specifications.Manufacture of components is similarly controlled bothdimensionally and with regard to heat treatment.For a given pitch size of transmission chain, there is normally agiven breaking load. However, conveyor chain does not followthis convention. For each breaking load, conveyor chain hasmultiple pitch sizes available. The minimum pitch is governed bythe need for adequate sprocket tooth strength, the maximumpitch being dictated by plate and general chain rigidity. Thenormal maximum pitch can be exceeded by incorporatingstrengthening bushes between the link plates, and suitable gapsin the sprocket teeth to clear these bushes.CHAIN TYPESThere are two main types of conveyor chain - hollow bearing pinand solid bearing pin.Hollow Bearing Pin ChainHollow pin conveyor chain offers the facility for fixing attachmentsto the outer links using bolts through the hollow pin andattachment, this method of fixing being suitable for use in mostnormal circumstances. The attachments may be bolted up tightor be held in a ‘free’ manner. Bolted attachments should onlyspan the outer link as a bolted attachment spanning the innerlink would impair the free articulation of the chain.RENOLDwww.renold.com engineering excellence67
Designer GuideSolid Bearing Pin ChainSolid bearing pin chain, while having exactly the same gearingdimensions in the BS series of chain as the equivalent hollow pinchain, i.e.pitch, inside width and roller diameter, is more robust witha higher breaking load and is recommended for use where morearduous conditions may be encountered.On other chain or where only small quantities are involved, separateattachments are used, as shown in Fig. 2(b). These are usuallywelded to the chain depending on the particular chain series andthe application. Alternatively, (see Fig 2(c)), K attachments may bebolted to the chain either through the hollow bearing pins, or byusing special outer links with extended and screwed bearing pinends.Fig. 2RENOLDDeep Link ChainRENHollow and solid pin chain has an optional side plate designknown as deep link. This chain’s side plates have greater depththan normal, thus providing a continuous carrying edge above theroller periphery.4OLDaOLDRENbc(a) K1 bent over attachment.(b) K1 attachment, welded to link plate.RENOLDRENOLD(c) K2 attachment bolted through hollow bearing pin.INTERNATIONAL STANDARDSConveyor chain, like transmission chain, can be manufactured to anumber of different international standards. The main standardsavailable are:F AttachmentsThese attachments as shown in Fig. 3 are frequently used forpusher and scraper applications. They comprise a wing with avertical surface at right angles to the chain. They can be fitted toone or both sides and are usually secured by welding. Each wingcan be provided with one or two holes, being designated F1 or F2respectively.British Standard - BSThis standard covers chain manufactured to suit the British marketand markets where a strong British presence has dominatedengineering design and purchasing. The standard is based on theoriginal Renold conveyor chain design.Fig. 3ISO StandardChain manufactured to ISO standards is not interchangeable withBS or DIN standard chain. This standard has a wide acceptance inthe European market, except in Germany. Chain manufactured tothis standard is becoming more popular and are used extensivelyin the Scandinavian region.CHAIN ATTACHMENTSAn attachment is any part fitted to the basic chain to adapt it for aparticular conveying duty, and it may be an integral part of thechain plate or can be built into the chain as a replacement for thenormal link.K AttachmentsThese are the most popular types of attachment, being used onslat and apron conveyors, bucket elevators etc. As shown in Fig.2 they provide a platform parallel to the chain and bearing pinaxes. They are used for securing slats and buckets etc. to thechain. Either one or two holes are normally provided in theplatform, being designated K1 or K2 respectively. K attachmentscan be incorporated on one or both sides of the chain. For themore important stock pitches where large quantities justify the useof special manufacturing equipment, the attachments areproduced as an integral part of the chain, as shown in Fig. 2(a).Here the platform is a bent over extension of the chain plate itself.ab(a) F1 attachments welded to link plates on one or both sides ofthe chain as required.(b) F2 attachments welded to link plates on one or both sides ofthe chain as required.Spigot Pins and ExtendedBearing PinsBoth types are used on pusher and festoon conveyors and trayelevators, etc. Spigot pins may be assembled through hollowbearing pins, inner links or outer links. When assembled throughlink plates a spacing bush is necessary to ensure that the insidewidth of the chain is not reduced. Gapping of the sprocket teeth isnecessary to clear the bush.Solid bearing pin chains can have similar extensions at the pitchpoints by incorporating extended pins. Both spigot pins andextended pins, as shown in Fig. 4, can be case-hardened on theirworking diameters for increased wear resistance.Fig. 4OLDRENaOLDRENb(a) Spigot pin assembled through outer or inner link.(b) Spigot pin bolted through hollow bearing pin.(c) Extended bearing pin.68engineering excellence www.renold.comc
Designer GuideStaybarsTypes of mechanical handling equipment that use staybars arepusher, wire mesh, festoon conveyors, etc., the staybars beingassembled in the same manner as spigot pins. When assembledthrough link plates a spacing bush and gapping of the sprocketteeth are necessary.The plain bar-and-tube type shown in Fig. 5 has the advantage thatthe staybar can be assembled with the chain in situ by simplythreading the bar through the chain and tube. The shouldered bartype has a greater carrying capacity than the bar-and-tube type.Staybars are normally used for either increasing overall rigidity bytying two chains together, maintaining transverse spacing of thechains, or supporting loads.Fig. 5attachments are intended for lighter duty, but for heavier duty apair of attachments on one link is connected by a spacer blockto form a pusher attachment. This increases chain rigidity andpushing area.Fig. 8ab(a) S attachment outer plate; assembled on one or both sidesof chain as required.(b) Pusher attachment.4OLDRENDrilled Link PlatesOLDRENab(a) Staybar bolted through hollow bearing pin.(b) Staybar assembled through outer or inner link.Plates with single holes as shown in Fig. 9(a) are associated withthe fitting of staybars or spigot pins. Where G or K attachmentsare to be fitted then link plates with two holes as shown in Fig.9(b) are used. Where attachments are fitted to inner links thencountersunk bolts must be used to provide sprocket toothclearance.Fig. 9G AttachmentsAs shown in Fig. 6 this attachment takes the form of a flatsurface positioned against the side of the chain plate and parallelto the chain line. It is normally used for bucket elevators andpallet conveyors. When the attachment is integral with the outerplate then the shroud of the chain sprocket has to be removed toclear the plate. G Attachments are normally fitted only to oneside of the chain.Fig. 6ab(a) G2 attachment outer plate.(b) G2 attachment, welded or rivetted to link plate.abOutboard RollersThe main reasons for using outboard rollers are that theyincrease roller loading capacity of the chain and provide astabilised form of load carrier. As shown in Fig. 10 the outboardrollers are fixed to the chain by bolts which pass through hollowbearing pins. Outboard rollers have the advantage that they areeasily replaced in the event of wear and allow the chain rollers tobe used for gearing purposes only.Fig. 10 Outboard rollers.L AttachmentsThese have some affinity with the F attachment, being in a similarposition on the chain. A familiar application is the box scraperconveyor. As shown in Fig. 7 the attachments are integral with theouter plates, being extended beyond one bearing pin hole andthen bent round. The attachments can be plain or drilled with oneor two holes, being designated L0, L1 or L2 respectively. They canbe supplied on one or both sides of the chain. With this type ofattachment the chain rollers are normally equal to the plate depth,or a bush chain without rollers is used.Fig. 7OLDRENChain JointsConveyor chain is normally supplied in convenient handlinglengths, these being joined by means of outer connecting links.This can be accomplished by the use of any of the following:Fig. 11OLDRENL2 attachments on both sides of the outer link.S and Pusher AttachmentsThese are normally used on dog pusher conveyors. As shown inFig. 8 the S attachment consists of a triangular plate integral withthe chain plate; it can be assembled on one or both sides of thechain, but may also be assembled at the inner link position. SNo. 107Outer link used for rivettingchain endless. It is particularlyuseful in hollow bearing pinchains where the hollow pinfeature is to be retained.www.renold.com engineering excellenceNo. 69Bolt-type connecting linkwith solid bearing pin. Looseplate is a slip fit on the bearingpins and retained by selflocking nuts.69
Designer GuideFig. 12Selection of Chain PitchNo. 58No. 86On lower breaking strengthchain a soft circlip retains theconnecting plate in positionon the pins, the connectingplate being an interference fiton the bearing pins.4In general the largest stock pitch possible consistent with correctoperation should be used for any application, since economicadvantage results from the use of the reduced number of chaincomponents per unit length. Other factors include size of bucketor slats etc., chain roller loading (see Page 73) and the necessityfor an acceptable minimum number of teeth in the sprocketswhere space restriction exists.A modified version of thebolt-type connecting link.The connecting pins areextended to permit thefitment of attachments onone side of the chain only.CHAIN PULL CALCULATIONSThe preferred method of calculating the tension in a conveyorchain is to consider each section of the conveyor that has adifferent operating condition. This is particularly necessary wherechanges in direction occur or where the load is not constant overthe whole of the conveyor.Fig. 13No. 11For uniformly loaded conveyors there is a progressive increase inchain tension from theoretically zero at A to a maximum at D. Thisis illustrated graphically in Fig. 14 where the vertical distancesrepresent the chain tension occurring at particular points in thecircuit, the summation of which gives the total tension in the chain.No. 85Fig. 14For 4,500 lbf series chain only,circlips are fitted to both endsof hollow connecting pins.Similar to No. 86 but allowsattachments to be bolted toboth sides of the chain.Total chain tensionCDTravelBAdvantages of Renold ConveyorChainYADriverThus, in Fig. 14 the maximum pull at D comprises the sum of:These can be summarised as follows:-(a)a. Large bearing areas and hardened components promotemaximum life.b. Low friction due to a smooth finish of the components.c. The inclusion of a chain roller and the high strength toweight ratio enable lighter chain selection and lower powerconsumption.d. The use of high grade materials ensures reliability ononerous and arduous applications.e. The facility to obtain a variety of pitches with each chainbreaking strength and a variation in attachment typesprovides adaptability.f. The accuracy of components provides consistency ofoperation, accurate gearing and low sprocket tooth wear.The latter is particularly important in multistrand systemswhere equal load distribution is vital.BASIC REQUIREMENTSTo enable the most suitable chain to be selected for a particularapplication it is necessary to know full applicational details suchas the following:Type of conveyor.Conveyor centre distance and inclination from the horizontal.Type of chain attachment, spacing and method of fixing to thechain.Number of chains and chain speed.Details of conveying attachments, e.g. weight of slats, buckets, etc.Pull due to chain and moving parts on the unloaded side.(b)Extra pull required to turn the idler wheels and shaft.(c)Pull due to chain and moving parts on the loaded side.(d)Pull due to the load being moved.If it is imagined that the chains are ‘cut’ at position X then therewill be a lower load pull or tension at this position than at Y. Thisfact is significant in the placing of caterpillar drives in complexcircuits and also in assessing tension loadings for automatic takeup units.This principle has been used to arrive at the easy referencelayouts and formulae (Page 80 - 81) to which most conveyor andelevator applications should conform. Where conveyors do noteasily fit these layouts and circuits are more complex then seepage 82 or consult Renold Applications Department for advice.FACTORS OF SAFETYChain manufacturers specify the chain in their product range bybreaking load. Some have quoted average breaking loads, somehave quoted minimum breaking loads depending upon their levelof confidence in their product. Renold always specify minimumbreaking load. To obtain a design working load it is necessary toapply a “factor of safety” to the breaking load and this is an areawhere confusion has arisen.As a general rule, Renold suggest that for most applications afactor of safety of 8 is used,Working Load Description of material carried, i.e. weight, size and quantity.Method of feed and rate of delivery.70Xengineering excellence www.renold.comBreaking Load8
Designer GuideOn first inspection, a factor of safety of 8 seems very high andsuggests that the chain could be over-selected if this factor isapplied.If, however, we examine the situation in detail, the following pointsarise:1. Most chain side plates are manufactured from low or mediumcarbon steel and are sized to ensure they have adequatestrength and resistance to shock loading.Fig. 15LOAD2. These steels have yield strengths that vary from 50% to 65% oftheir ultimate tensile strength. This means that if chains aresubjected to loads of 50% to 65% of their breaking load, thenpermanent pitch extension is likely to occur.TEMPERATURE/LUBRICATIONLubrication-30 / 150 C150 - 200 C200 - 300 CRegularOccasionalNone81012101214121416In all the listed applications and conditions, the increase in factor ofsafety is applied with the object of lowering the pin/bush bearingpressure to improve the chain life.4CHAIN LIFEP(a) OMATERIALYIELD, POINTThere are a number of factors affecting the life of a chain in aparticular environment.EXTENSIONPERMANENTEXTENSION3. It is the tendency to over-select drive sizes “just to be sure thedrive is adequate”, and the motors used today are capable of upto 200% full load torque output for a short period.4. The consequences of this are that a chain confidently selectedwith a factor of safety of 8 on breaking load is in effect operatingwith a factor of safety of as low as 4 on the yield of the material,and 2 when the possible instantaneous overload on the drive isconsidered, and this is without considering any over-selection ofthe motor nominal power.5. A further consideration when applying a factor of safety to achain application is the chain life.The tension applied to a chain is carried by the pin/bush interfacewhich at the chain sprockets articulates as a plain bearing.Experience has shown that, given a good environment, and a cleanand well lubricated chain, a bearing pressure of up to 24N/mm2(3500 lb/inch2) will give an acceptable pin/bush life. A safety factor of8 will give this bearing pressure.In anything other than a clean well lubricated environment the factorof safety should be increased, thus lowering the bearing pressure, ifsome detriment to the working life of the chain is to be avoided.Table 1 gives a general guide to the appropriate safety factors fordifferent applications.Table 1 - Factors of 01214121416141618a. The load on the chain and therefore the bearingpressure between the pin and the bush.The design of conveyor chain is such that at the calculatedworking load of the chain (relative to the breaking load)then the bearing pressure between the pin and the bush will22be at a maximum of 24N/mm (3500lb/in ) for a clean welllubricated environme
Selecting the right chain for a given application is essential to obtain long service life. This guide has been developed for use with Renold conveyor chain to help in specifying the right chain and lubrication for your conveyor system. The significance of the Renold conveyor chain design is
To place an order please use the Conveyor Request Form (page 37) or visit the online Belt Conveyor Confi guration Tool at www.robotunits.com Description Frame Width F max. 3) Belt Conveyor 40 40 mm 300 N Belt Conveyor 40 80 mm 700 N Belt Conveyor 40 120 mm 1100 N Belt Conveyor 40 160 mm 1500 N Belt Conveyor 40 200 mm 1900 N Belt Conveyor 40 .
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Plate Conveyor Belt Plate conveyor belt can be divided into three types: chain, perforated and convex plate conveyor belt. Chain plate conveyor belt can be made into L-shaped, U-shaped or rectangular according to the requirement of space. The holes on the surface of perforated plate conveyor belt with good heat dissipation function.
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Conveyor Systems In Operations 1970 First drag chain conveyor for 600 t/h 1981 First Vertical screw conveyor 2004 RUD India found 1960 First belt type bucket elevator 1875 RUD Ketten Rieger & Dietz GmbH u. Co. KG is founded 1932 Engineering Office for Conveyor systems is opened. Design of the first Continuous conveyor for bulk materials 1940 In .
This paper is focused on alteration of chain link design in drag chain conveyor system. The main components of the equipment include chains, sprocket, drive mechanism and casings. [3] Numerous types of conveying equipments including drag chain conveyors are produced by Mahindra Tsubaki Conveyor Systems (MTC). A range of chain
The materials used for components of drag chain are as follows- Table 1:- Materials of drag chain conveyor components. Sr. No. Name of Drag Conveyor Chain Part Material 1. Inner Link Plate C45 2. Outer Link Plate C45 3. Flights C45 4. Pin 40Cr1Mo60 5. Bush 40Cr1Mo60 6. Split pin M.S. II. DESIGN OF DRAG CONVEYOR CHAIN 2.1 Chain Velocity (v):
The blue light protocol is subject to CTR Policy exemplar standard 11 as follows “CTRs and any related recording or disclosure of personal information will be with the express consent of the individual (or when appropriate someone with parental responsibility for them), or if they lack capacity, assessed to be in their best interests applying the Mental Capacity Act 2005 and its Code of .
