Basics of Conveyor Engineering Hardware

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Perspectives on Material Handling Practice

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p r o v i d e a p o i n t o f r e f e r e n c e a s t o h o w t h e i n d u s t r y i s c h a np r o v i d e a p o i n t o f r e f e r e n c e a s t o h o w t h e i n d u s t r y i s c h a np r o v i d e a p o i n t o f r e f e r e n c e a s t o h o w t h e i n d u s t r y i s c h a np r o v i d e a p o i n t o f r e f e r e n c e a s t o h o w t h e i n d u s t r y i s c h a n g i n g a s w e l l a s i n s i g h t g i n g a s w e l l a s i n s i g h t g i n g a s w e l l a s i n s i g h t g i n g a s w e l l a s i n s i g h t

i n t o a c c e p t e d p r a c t i c e d u r i n g t h i s p e r i o d . I n m a n y c a s e s t h e a u t h o r s c r e d i t e d h a v e i n t o a c c e p t e d p r a c t i c e d u r i n g t h i s p e r i o d . I n m a n y c a s e s t h e a u t h o r s c r e d i t e d h a v e i n t o a c c e p t e d p r a c t i c e d u r i n g t h i s p e r i o d . I n m a n y c a s e s t h e a u t h o r s c r e d i t e d h a v e i n t o a c c e p t e d p r a c t i c e d u r i n g t h i s p e r i o d . I n m a n y c a s e s t h e a u t h o r s c r e d i t e d h a v e

e i t h e r c h a n g e d j o b s o r a r e n o l o n g e r i n t h e i n d u s t r y . S o m e c o m p a n i e s a s w e l l h a v e e i t h e r c h a n g e d j o b s o r a r e n o l o n g e r i n t h e i n d u s t r y . S o m e c o m p a n i e s a s w e l l h a v e e i t h e r c h a n g e d j o b s o r a r e n o l o n g e r i n t h e i n d u s t r y . S o m e c o m p a n i e s a s w e l l h a v e e i t h e r c h a n g e d j o b s o r a r e n o l o n g e r i n t h e i n d u s t r y . S o m e c o m p a n i e s a s w e l l h a v e

b e e n t h e s u b j e c t o f m e r g e r s o r r e o r g a n i z a t i o n w i t h a n e w c o r p o r a t e b e e n t h e s u b j e c t o f m e r g e r s o r r e o r g a n i z a t i o n w i t h a n e w c o r p o r a t e b e e n t h e s u b j e c t o f m e r g e r s o r r e o r g a n i z a t i o n w i t h a n e w c o r p o r a t e b e e n t h e s u b j e c t o f m e r g e r s o r r e o r g a n i z a t i o n w i t h a n e w c o r p o r a t e i d e n t i t y .i d e n t i t y .i d e n t i t y .i d e n t i t y .

BASICS OF CONVEYOR ENGINEERING HARDWARE

BY

MIKE COLEMAN

INTERLAKE CONVEYOR SPECIALIST

NA 94 FORUM ABSTRACT In the conveyor business there is never a perfect solution, only partial answers to the solution, and that is the reason for this seminarto familiarize you with the different types of equipment available, and their application. GATHER FACTS Certain questions must first be answered before you can even begin to conceptualize that conveyor system. An overall objective must first be set, and a basic understanding of the type of system is important. A few examples of the type of systems are warehousing, receiving, packaging, shipping, production (both flexible, and progressive). It is also important to consider the size, shape, and age of the building, and possible future expansions. Environmental conditions must also be taken into account like temperature, and humidity. Additional information should include, sales forecasts, combined with production capabilities, keeping in mind the need for flexibility since manufacturing is ever changing in this world economy. But the most important thing to remember when considering a conveyor system is the KISS principle, for often times we get carried away with the equipment options, and before you know it, we have lost the true objective of the system, with over design, and expensive features. Future



considerations must also be taken into account early on, so your system must be adaptable, and flexible for a phase-in expansion. Once you have an overall picture, or sequence of operations, then specific questions must be asked. Load Characteristics are vital, and include the size, shape, weight, and material to be conveyed. The footprint is important for it is what the conveyor will see, and will help determine the best type of equipment to use. Rate of flow is important for it will determine the speed that the conveyor needs to run, and product orientation if you are interfacing with automated equipment, and or need to incorporate accumulation of products. Now that you have a general layout, combined with the specific information of your system, you can begin to specify the type of equipment required. EQUIPMENT APPLICATION There are multiple functions for each type of conveyor. It is now a question of applying the best- suited equipment, while staying within your budget. GRAVITY Gravity conveyor is your least expensive equipment, and is suitable for most manual applications. It is often used to pass orders from picking zones, or for staging material to shipping, packaging, or inspection. Since it is non-powered, it is safe and easy to work with. If the conveyor is to be pitched, it is important to know the weight of the product, for a heavy carton will build up more momentum than a lighter carton. It is also important to know how the conveyor is being loaded, for there is a wide range of capacities. Hand loading applications would require a lighter gage material than fork truck loading due to less shock. Also take into account the side frames for a structural member may be needed to resist impact. POWERED CONVEYOR There are many types, and styles, but they all have one objective, and that is to move the product from one point to another as efficiently as possible. From the application chart, you can see that belt conveyors have a broad range of usage. They are the least expensive type of powered conveyor due to the limited number of bearings required. Horizontal belts can handle most product shapes, and weights. There are two types, a slider bed, and a roller bed. A slider bed is a steel sheet that the belt rides over and a roller bed is just as the name implies. A slider bed is most often used for small lightweight products, where a roller bed is used for heavier products with longer runs. Belt pull is the limiting factor, and should be determined by your conveyor supplier. An incline/decline belt conveyor is used to move product from one elevation to another. A ruff top belt is usually supplied, which grips the product, and prevents it from freewheeling or sliding. It is important to know the maximum incline angle to prevent product tumbling.



LIVE ROLLER CONVEYOR Live Roller conveyor is the next conveyor of choice, and covers a wide range of application. It is used mostly in areas where product accumulation or staging is important. Live Roller conveyor comes in many styles. They are, belt driven, cable drive, and shaft driven. Each has it's own advantages, and disadvantages, in regards to usage and flexibility. Belt driven live roller (BDLR) is where the carrying rollers (rollers holding the product) are powered by a belt. This belt is wedged between the carrying rollers and the pressure rollers. The pressure rollers can be adjusted up or down to increase or decrease the driving force. Another set of rollers is required for this conveyor but is not shown, and that is the return rollers used to return the belt to its starting position. Most BDLRs are used for medium to heavy-duty application, where significant driving force is required, such as through merges, divert arms, and pallet handling applications. A shaft driven live roller (Lines shaft) is the carrying rollers are individually powered by an elastomeric belt, which is driven off a main shaft. This type of conveyor is used mostly in light to medium duty applications, and lends itself to multiple accessories powered by a single drive. Cable driven live roller is similar to lineshaft, except the carrying rollers are powered by a steel cable that are able to snake around through the curves, and straight sections. It is also a light to medium duty conveyor. Live roller conveyors lend themselves better for accumulation applications both zero pressure, and minimum pressure because the power source can be dropped out of a zone, or adjusted to limit the amount of driving force required to move the product while at the same time maintain product flow throughout. CHAIN DRIVEN LIVE ROLLER CONVEYOR Chain Driven Live Roller (CDLR) is used for heavy-duty applications, and comes in both transport and accumulation models. Like any powered roller conveyor the footprint is important to provide smooth roller to roller flow, so if the pallet has bottom slats, it is a good idea to have them running length wise or perpendicular to the rollers. This type of conveyor is powered by a series of chains that is connected progressively to each roller, or by a single chain that runs the length of the conveyor. The progressive roller to roller requires two sprockets welded to each roller, where a single chain only requires one sprocket. Each has its application, but the heavier the load the more chain pull is required which would dictate one over the other. Due to the heavy loads being transported, a fork truck is often required, consequently, a structural frame and heavy gage roller is often required to withstand the abuse factor. Also, a toe in or toe out frame configuration may be needed to mount the rollers high opposite the chain guard to allow ease of loading and unloading. Roller capacity can run as high as 1200 lbs each so we are talking heavy stuff here.



SUMMARY This paper should provide a better understanding of the type of equipment available and the primary application. As you have noticed, different types of equipment can be used for the same application; but remember the future and this ever changing world market, for your system today needs to be flexible, changeable and simple. It is a major investment that you should not outgrow. EXHIBITS Gravity Conveyor Gravity roller conveyors provide one of the most versatile and economical means of moving portable applications. Gravity conveyors can quickly move large quantities of items in virtually any direction with a minimum of effort and expense. Gravity conveyors move product in two ways: on a pitch, utilizing the natural flow of gravity or on a level line where conveyance of the item in accomplished by pushing. Gravity, or non-powered roller conveyors, is ideal for moving most unit loads that have a firm, flat bottom surface. They can be used in both permanent and portable applications. To select the proper equipment for the required application, the following steps must be considered.

1. Load Characteristics 2. Conditions and Bearing Selection 3. Roller Center Spacing 4. Roller Capacity 5. Width and Settings 6. Frame Requirement 7. Support Capacity 8. Conveyor Pitch 9. Support Heights and Quantities

Load Characteristics The single most important consideration to insure your system reliability is known as the footprint, which is the bottom surface of the load that is to be conveyed. The load bottom must be firm and free of projections, which could prevent smooth travel over rollers. A slipsheet could provide the necessary rigidity. If at this step, all load characteristics are not favorable, do not proceed. Consider a power conveyor.



Conditions and Bearing Selection

Bearings OPEN DRY BEARING Open dry bearings offer the least resistance to turning of all bearing types. They are constructed with an outer shield, which is fixed to the stationary inner race of the bearing and does not touch any rotating part. Manufactured with a light oil lubricant, the open dry bearing gives satisfactory results in most normally clean, dry, indoor applications.



DUST PROTECTED BEARINGS Dust protected bearings, non-lubricated, have the same easy rolling action as a plain bearing because the dust shield is a non-contact type seal. The shield, which is fit to the stationary inner race does not touch any rotating parts of the bearing. In a reasonably moisture free environment, excellent results are achieved with absolutely no lubrication. FACTORY LUBRICATED BEARINGS The lubricated bearings are similar in construction to the dust protected incorporating the same dust shield arrangement with an additional rear grease seal. The factory-lubricated bearings are recommended for all powered roller applications, both for live roller and belt conveyor applications. Caution should be used in applying this construction in areas where excessive grit or dust exists, as there are no means provided for regreasing these bearings as there are with pressure-lubricated construction. PRESSURE LUBRICATED BEARINGS The pressure-lubricated bearings are similar in construction to the factory-lubricated bearings: however, requiring in application the necessity of drilling the hex axle for grease fittings for delivery of grease to internal parts of the bearing. Grease delivered under pressure to the interior of the bearings forces out old grease, thereby producing a new effective seal. The advantages of the re-greasable feature are obvious when considering application in extremely dirty environments. Determine Roller Center Spacing A MINIMUM OF THREE ROLLERS MUST SUPPORT THE SMALLEST UNIT LOAD. Divide the minimum package length you anticipate conveying in your system by three (or the number of rollers needed) to arrive at the roller center-to-center distance. Choose a roller section with roller centers the same or less than this figure.



Determine Roller Capacity Roller capacity is determined by dividing the weight of the heaviest load by the minimum number of rollers that will carry the load at any single moment.

Determine Width & Settings Straight Sections STRAIGHT SECTIONS If your application consists only of straight conveyor sections, the recommended conveyor width is: Conveyor Width = Package Width + 2 inches



Determine Frame Requirement To extend the life of the conveyor or to avoid damage from overloading, it is best to be on the safe side in calculating frame capacity. Allow for extra loading. In many cases conveyors are subjected to greater abuse and loads than they were intended for. Frame requirements should be carefully calculated. Locating supports on closer centers is one way to increase frame capacities. In doing this, compare the cost of an increased frame to the number of extra supports to see which method is most economically feasible. When figuring capacities, include the weight of the conveyor section and be sure to check the capacities of each type of frame against the total load. FORMULA: Live Load: Multiply Number of Loads in 10-0 Long Section x Weight of Each Load + Dead Load: Multiply Number of Rollers in 10-0 Long Section x Weight on Each Roller = Total Load



DETERMINE SUPPORT CAPACITY: The supports to be selected must have a load carrying capacity equal to or greater than the maximum loading condition and weight of section itself.



Powered Conveyor Belt Conveyors Types and Applications Being the most versatile of power conveyor, belt conveyors are the most frequently used. One reason for the versatility is the work surface belt, which can handle loads of almost any shape and over a moving platform for process or production work. Belt conveyors are also one of the least expensive power conveyors. Slider Bed The belt slides over a continuous metal bed, which is attached between the tops of the conveyor channel frames. Because support for the entire belt surface is provided, the belt friction (30% friction coefficient) is increased, thus limiting loads to 52 lbs. per sq. ft. or less. Operation is quiet and the bed offers a no-sag, no bump surface. Slider bed conveyors are excellent for production work where small parts of varying sizes and shapes must be carried or assembled. The surface remains constantly flat.



Roller Bed The belt rolls over rollers rather than a metal bed. Friction is greatly reduced thus smaller motors and drives can be used. For light loads, one roller is sufficient under each load but for heavier loads and inclines, two or more rollers should be used. (See your conveyor supplier for specific roller capacities.)

Inclines and Declines When elevation must be changed, incline or decline belt conveyors are used at a maximum 300 angle. This rule can only be used for evenly weighted loads! A vertical line dropped from the exact center of the load (center of gravity) should fall within the center one third of the bottom of the load. Outside of this area the load would be unstable. If the weight within the carton is off center or unevenly distributed, do not use this rule! Testing may be necessary to determine the center of gravity and exact incline.

Example: A package is 28L x 20H x 12W X = L/H X = 28/20 = 1.4 Maximum incline angle = 25 degrees



Handy Incline Table This chart is also to be used only with evenly weighted loads. Divide carton length by carton height to find: X = L/H On the table, the degree of include next to your value of X will be the maximum incline guideline you should use.



Belt Driven Live Roller Curves Belt driven curves are used with live roller conveyor. However, their use does have some limitations, such as it can be used for transportation only and cannot accumulate. Pressure rollers are not used in curves. In their place, sheaves along the inner frame (smaller radii) are used to guide a V-Belt and apply belt pressure to the carrying rollers. The carrying rolls thru the curve are tapered to keep loads properly aligned. There is a maximum 400 lb. limit of distributed load per curve. Powered curves generally operate faster than straight conveyors to keep loads separated and from bumping each other. CHAIN DRIVEN LIVE ROLLER CONVEYOR Chain driven live roller conveyors utilize a roller bed for the carrying space. They provide controlled movement of a great variety of commodities from the lightest to the heaviest loads. Unit loads travel directly on the roller surface. The positive drive afforded by chain on sprockets makes chain driven live roller conveyor the choice for heavy loads (pallets. etc.) and for conveyors used in applications where heat, dirt, oil, grease or other contaminants may cause belt damage. Two sprockets are welded to each roller and individual loops of chain connect rollers in a staggered pattern. The driving chain or chains are at one end of the rollers and are shielded or guarded. This driving arrangement is desirable for heavy loads and for applications, which require frequent stopping or reversing. The path is usually level, but can be slightly inclined or declined, limited by the coefficient of friction between the rollers and the load. Because the drive is positive, there is no slippage: all rollers turn at the same speed. Both straight sections and curves are available.

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Basics of Conveyor Engineering Hardware

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