Pallet Rack

Selecting the appropriate rack system depends on density requirements or combination of systems. Different types are:

 Selective Rack: so called because it allows for easy selection, normally by service (truck) aisles. Selective Rack does not make the most complete use of the floor space because of the aisles required, but may be a solution for many Companies.

Drive-In Rack: increases density and is utilized where group pallet selection is more likely than an individual pallet selection. With Drive-in Rack, loading and unloading within a bay must be done from the same aisle. A Drive-Through Rack, however, permits loading and unloading from both ends of a bay.

Cantilever Rack: is primarily utilized to store bulk items such as building materials (lumber, pipe, drywall) and furniture. It is commonly found in home centers and furniture warehouses etc.

Also, there are two types of steel that are used in the majority of pallet racks.Roll-form steelrack: frames and beams are fashioned from steel coils and bent into a tubular shape. Structural steel: frames and beams are hot-rolled into channel at the mill. 

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Carton Flow

Carton Flow can dramatically improve warehouse efficiency by organizing product and rotating stock automatically. Long, straight and dedicated lanes maintain product organization and keep labor costs down. Storage space can be increased up to 60% by using a minimum of 22% less floor space, thereby keeping building costs down. Typically, Carton Flow systems use about half the floor space that standard pallet rack occupies and the difference can be more dramatic with multi-level systems . some applications:

 Gravity: systems requires less capital than maintenance-prone automated systems.

 Flow Rack: can be used with pallet rack to maximize your storage space. The pallet rack can create storage above the flow rack system. Using the Universal Hanger Clips in conjunction with carton flow shelves you can even turn your existing static pallet rack into a dynamic carton flow system. In many ways, a Carton Flow Rack is like a conveyor within a rack structure .Carton Flow Rack is used for both cartons and pallets. Most applications are where the carton or pallet at the front is going to be picked from, and the ones behind are reserve storage. By achieving high-density, dynamic storage, Carton Flow Rack offer excellent payback. As well, they help keep people (i.e. the pickers) at a safe distance from the forklifts that are replenishing the racks.

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Conveyor

Accumulation conveyors: are used to transport and accumulate cartons and unit loads.  These conveyors are used to hold product for gradual release into a cell or work area.  Such a conveyor might be used for instance to release one package at a time to a robotic pickup station, or to release a part to a dedicated machine in an industrial environment that performs some action on the part or it might be used in a distribution system to release a group of cases onto a spur for palletizing.
There are two major types of conveyors in this category:"Minimum Pressure Conveyors" and "Zero Pressure Conveyors".  In this case the term pressure refers to the amount of force exerted from the conveyor onto a package or part. 

A Minimum Pressure Conveyor: releases parts gradually into a work cell, but the parts are touching one another and exerting a slight force on one another.  A Zero Pressure Conveyor also releases parts gradually into a work cell, with no part touching any other part.  With conveyor minimum pressure accumulation, the product is accumulated and the driving force is not removed. It is called minimum pressure because the pressure of the driving force is kept to a minimum. Pressure will build up as more product accumulates, but can be overcome with controls designed specifically for the application. The advantage to a minimum pressure conveyor is a higher discharge or single load release rate than with zero pressure accumulation.

Zero pressure accumulation: occurs when the driving force is completely removed form the load. This is usually accomplished by way of sensors in combination with various mechanical means such that when a load is stopped on a sensor, the driving force in the zone behind the stopped load is dropped away. When the next load is driven into the now dead zone, it too will stop, causing a like chain reaction upstream, or until such time that the first stopped load is released and moves on. Discharge from an accumulation point can be either one load at a time or a so-called slug discharge, where a pre-specified number of loads are released at one time.  A slug is a very loose term and can be any number of units and is defined by the system designers.
So, in summary, a minimum pressure conveyor is a contiguous conveyor system.  There are no zones and the amount of sensors and controls needed is at a minimum. On the other hand, a zero pressure system can be comprised of almost any type of conveyor, roller, chain, belt etc.  You need not be so careful with the design because the weight and dimensions are not so critical.  A zero pressure system is by definition a zone type of system, where each conveyor section is a zone that will need to be controlled separately.  So, more sensors and software are involved.

Belt conveyor: as the name implies is comprised of a durable material (the belt) that encircles two or more rollers.  One of the rollers has a drive mechanism (usually an electric motor) attached to it either directly or through a gear reducer.  The other roller is usually unattached to any type of drive and allowed to roll freely.Belt Conveyors are the most commonly used bulk handling conveyors in history due to their reliability, versatility, and range of capacities.  Materials from fine powders to large, lumpy stone or even discrete parts can be handled on a belt conveyor.  This type of conveyor can exist as a single wide belt or two or more "V" belts.  Usually a single wide belt is used in an application where a single item is to be conveyed, that has little or no chance of separating. 

For example, you might use a single conveyor belt system to convey a small section of carpet, a tray of parts or other single unit materials from one location to another. You might use a "V" belt type system when handling material that could break or come apart.  If the material does come apart, you want the broken or detached material to fall through the belts and onto the floor rather than impeding the material behind it.  This type of belt conveyor is good for handling glass and other breakable items.Conveyor belts are available in widths up to 100 inches. It is the most costly part and the component is most susceptible to damage. The parts that make up the belt are: the covers (top and bottom), and the carcass.

.  You must be knowledgeable of your application and pick a belt that best suites the product that you convey.The power required to drive a belt conveyor is derived from the tensile forces required to propel or restrain the belt at the design speed. These include: the resistance of the drive, conveyor components, and material; the acceleration of the material; and the gravitational forces required to lift or lower the material. A wide variety of belt conveyors are used in material handling systems. The most popular types are the; flat, telescoping, trough, and magnetic belt conveyor.

Pallet conveyor: are typically either a Roller Conveyor or a Chain Conveyor.  Some pallet conveyors can even be a combination of these two types of conveyors.  Factory automation systemRoller and chain conveyors are good for transporting heavy loads such as pallets, drums or castings.  Both of these conveyors can handle wet or oily loads and can also accomodate a more typical dry load.  Although either type of conveyor can be built to almost any specification; common widths are anywhere from a few inches up to 12 ft, and common lengths are 5ft, 8ft and multiples of 5 ft up to around 40 ft.  The most common widths are from 36 inches up to 60" or approximately the size of the more common pallets. Frames are typically constructed of 4 gauge steel channels and the rollers themselves are most often 2 1/2" in diameter and constructed of 11 gauge steel, although larger diameters are available. Speeds vary, with common speeds being 30 to 60 feet per second, but, speeds up to 150 feet per second can be achieved.  Common spacings between rollers in inches are: 3, 5, 6, 7.5 10 and 12 inches. Chain sizes can vary between RC 40, 50, 60 or 80, with RC 80 being the more heavy duty.  Conveyors are driven by 1/4 HP up to 5 HP motors. 

 Roller conveyors: take in a variety of conveyors, standard roller, skate wheel and ball conveyors.  Even though they each look different,what they all have in common is that they all have some type of rolling surface in contact with the unit load being transported.  Distribution System both ball conveyors (or ball transfers) and skate wheel conveyors rely upon gravity or a human operator as the driving force.  A ball transfer table, pictured at right, is an easy and economical method of moving a part from one conveyor to another or from a conveyor to an inspection table.  As can be seen on the left, the balls that make up the table can be composed of stainless steel, for more corrosive environments, or they can be a polycarbonate composite that will minimize scratches to the product being moved.  Gravity skatewheel conveyors are used primarily for lightweight packages. 

   Chain driven live roller conveyor:  Each roller has two sprockets built into it.  A gear reduced motor coupled with a chain to the first roller turns that roller. A chain couples the first roller to the second and so on down the line of rollers. Self powered roller conveyor consists of a single powered roller connected to adjacent rollers by a band, in a similar fashion as a line-shaft driven roller conveyor.  Each roller is connected to a roller on either side of it, in this manner one powered roller can drive up to 10 non-powered rollers.

 Gravity Conveyor: There is the gravity roller conveyor, which has no driving mechanism, it is usually inclined and the momentum of the material causes the rollers to turn; allowing the package to move across the rollers.  This is essentially a gravity conveyor that has a "V" belt running under one side or the other of the rollers.The "V" belt is in contact with the rollers and there will most likely be a tensioning adjustment, giving the designer the ability to increase or decrease the tension between the belt and the rollers.  As the belt moves, so do the rollers.  Line-shaft driven roller conveyors have a drive shaft that extends under the rollers in the direction of travel of the package, i.e., perpendicular to the roller.  The shaft has small rubber "bands" that twist around the shaft and can be also put around the roller.  This band causes the roller to turn.  Each roller has its own band. 

Slat conveyors: are noted for their versatility in handling a multitude of products, from raw materials through finished goods.  One of the most rugged and maintenance free of all conveyors, with slats typically made from steel or wood, these conveyors can handle hot, oily and abrasive materials where canvas or belt conveyors would wear out quickly or be impractical.  spiral conveyor  material handling equipmentAlthough slat conveyors have been used more in the past for these hot, oily abrasive tasks, modern slat conveyors are offering more and more functionality. 

Spiral conveyor: subset of the slat conveyor. Spiral is used in warehousing to move products from floor level to mezannine level (or vice versa).  These special spiral conveyors can also be used as a method of buffering product.The spiral conveyor is also reasonably easy to install, as it is shipped in one piece ready to be mounted in place.  Spiral conveyor slats are typically made of fiberglass or some other plastic composite material.  Spiral conveyors are also very resistant to spills, should they occur.All spirals are equipped with an automatic chain tensioning device and built-in overload protection. The chain tensioning device is spring operated and a proximity sensor is sensing the correct operating position of the device. The overload protection is accomplished by mounting the drive motor on an adjustable torque arm arrangement which will pivot during an overload condition. This motion will be detected by a proximity sensor which in turn will cause the motor to stop. As can be seen to the left, other arrangements can be made utilizing the spiral slat conveyor concept.  This conveyor not only moves product from a high level down to a low level, but also provides quite a bit of buffered space while it does it. 

 Even though this conveyor section seems long it still may only be driven by one motor.  Some vendors can make a conveyor section as long as 250 feet with only one motor drive unit.  material handling equipmentFinally, saving the best for last, we have a slat conveyor that is capable of high speed rotation of product. The loads can be rotated 180º or 90º in a continuous motion. This new conveyor is used in packing lines where products need to be rotated upside down or to one sidewithout delay or product damage.  This conveyor can accommodate a wide range of load sizes without adjustment.

Overhead conveyors: have been and will continue to be the industrial workhorses of our time.  Going high up into the rafters of our plants and utilizing hitherto unusable space, these conveyors move heavy products, provide a buffer of products and in the case of many operations provide drying or cooling time for paint, glue and other wet or hot materials before they get to the next step in the operation.  They can carry individual parts or racks full of parts, meandering through our plants, dipping down when needed to deliver or pick up theirload and then retreating back up, working unnoticed above our heads. 

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Mezzanines

 Mezzanine floor is a suspended or supported floor erected within a building, which is not part of the original structure. Such floors are an essential element of most warehouses these days, offering additional office or storage space without adding to the building footprint structure. A mezzanine floor consists of four major structural components: columns, beams, joists and decking. Columns are upright posts made of boxed section steel. Beams are 'I' section steel members that run across the top of the columns sitting on the cap plates. These can be any length and are securely bolted to the columns. Joists run at right angles to the beams and support the decking surface of the floor. These vary in length and rating depending on the use of the floor. Decking or floor surface can be chipboard, open steel grid or solid steel.

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Forklifts

Nearly every warehouse has a forklift - a tool capable of lifting thousands of pounds. A forklift is a vehicle similar to a small truck that has two metal forks on the front used to lift cargo. The forklift operator drives the forklift forward until the forks push under the cargo, and can then lift the cargo several feet in the air by operating the forks. The forks, also known as blades or tines, are usually made out of steel and can lift up to a few tons. Forklifts are either powered by gasoline, propane, or electricity.

Electric forklifts: rely on batteries to operate. Electric forklifts are great for warehouse use because they do not give off noxious fumes like gas powered machines do.Forklifts are most often used in warehouses, but some are meant to be used outdoors.

Gasoline or propane forklifts: are sometimes stronger or faster than electric forklifts, but they are more difficult to maintain, and fuel can be costly. Forklifts are most often used in warehouses, but some are meant to be used outdoors. It is important for forklift operators to follow all safety precautions when using a forklift. Drivers should be careful not to exceed the forklift's weight capacity. Forklift operators also need to be able to handle forklift's rear wheel steering. Driving a forklift is similar to driving a car in reverse, meaning that the driver must constantly steer to keep it moving in a straight line. The driver must be aware of the forklift's ever-changing center of gravity and avoid making any quick sharp turns or going too fast. It is advisable that anyone who operates a forklift befully trained and licensed.Forklifts have revolutionized warehouse work. They made it possible for one person to move thousands of pounds at once. Well-maintained and safely operated forklifts make lifting and transporting cargo infinitely easier.