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 hither to 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 their load and then retreating back up, working unnoticed above our heads.
Chain and Trolley
The I-Beam chain and conveyor system was the first type of overhead conveyor developed. It is, by far the simplest system. An I-Beam is hung from building supports making sure to keep the bottom of the "I" clear of all obstacles. A trolley is designed with roller bearing wheels that ride on each side of the beam. This trolley can have more than the two pictured wheels. Also, there can be wheels mounted perpendicular to the "I" that touch the upper or lower cross member of the "I", for stability. The I-Beam chain and trolley is a very simple type of conveyor that is conceptually easy to install and can handle large amounts of weight per trolley, typically several thousand pounds.
Enclosed Track
The enclosed track overhead conveyor system was developed later than the I-Beam system shown above. The trolley wheels are actually mounted inside the track, with the outer track protecting the chain and wheels from the surrounding environment. Dust, dirt, paint and other debris all accumulate on the outer track instead of the area where the wheels roll. Unlike the chain and trolley system shown above, the enclosed track system does not pick up these contaminants and pass them on to whatever part it is transporting. This can be extremely important in the case of a hot or wet part, where there is dirt or paint in the surroundings. The enclosed track system has a bend radius of approximately 2 feet, so it can more easily negotiate obstacles within the plant than the chain and trolley system, whose bend radius is closer to 4 feet. Also, while the track is slightly more expensive than the I-Beam used above, this cost is more than offset by the relative ease of installation and savings that this brings in installation labor costs. The enclosed track system is not usually used with extremely heavy loads though, typically a few hundred pounds per trolley is the limit.
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.
Both are examples of Spiral Conveyors.
Although slat conveyors have been used more in the past for these hot, oily abrasive tasks, modern slat conveyors are offering more and more functionality. A subset of the slat conveyor (spiral conveyor) is used in warehousing to move products from floor level to mezzanine level (or vice versa). These special spiral conveyors can also be used as a method of buffering product. Spiral conveyor slats are typically made of fiberglass or some other plastic composite material. Spiral conveyors are also very resistant to spills.
This conveyor not only moves product from a high level down to a low level, but also provides quite a bit of buffered space. 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.
This is 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 side without delay or product damage. This conveyor can accommodate a wide range of load sizes without adjustment.
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.
Ball Transfer Table
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 is an easy and economical method of moving a part from one conveyor to another or from a conveyor to an inspection table.
Skatewheel Conveyor
The skatewheel conveyor, also a gravity operated conveyor, is most often set at an incline so that material can be given a slight push by a human being and roll to the end of the conveyor. Gravity skatewheel conveyors are used primarily for lightweight packages. They are typically used in shipping departments, stocking areas, assembly lines.
Pallet conveyors are typically either a Roller Conveyor or a Chain Conveyor. Some pallet conveyors can even be a combination of these two types of conveyors.
Roller 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. 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.
Cross Transfer
This unit is used to move a pallet 90 degree from a roller conveyor to a chain conveyor (or vice versa). With the chain section down, the roller section allows the pallet to move from a previous section of roller conveyor onto the cross transfer. Once at the stopping position of the rollers, the chain section raises, lifting the chain section and the pallet on top of it above the rollers. With the chain section raised, the chains transport the pallet onto the next conveyor section.
A 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 in bulk handling. 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.
Conveyor belts are available in widths up to 100 inches. It is the most costly part and the component is most prone to damage. The parts that make up the belt are: the covers (top and bottom), and the carcass. The carcass provides: the tensile strength needed to start and move the loaded belt, the transverse and longitudinal flexibility required to allow the belt to both support the load and conform to the shape of the idlers when empty and to wrap around pulleys, the strength to resist impact forces. The cover's main function is simply to protect the carcass from damage.
A wide variety of belt conveyors are used in material handling systems. The most popular types are flat, telescoping, trough, and magnetic belt 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.
An example of Minimum Pressure Conveyor, calledLineshaft Conveyor.
There are two major types of conveyors in this category; "Minimum Pressure Conveyors" and "Zero Pressure Conveyors". 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 each another. A Zero Pressure Conveyor also releases parts gradually into a work cell, with no part touching any other part.
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.
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. One must be very careful when designing a minimum pressure system because proper operation is highly dependent upon the dimensions and weight of the specific packages involved.
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. Hence, more sensors and software are involved.
Today, conveyor is driven with an electrical motor through gear reduction, in the earlier times, it was driven by water power, animal power or even manually. This type of conveyor system dates back at least several centuries and was originally used to move grains and flour through mills.
Modern conveying systems began in the 19th century as the industrial revolution demanded more efficient methods for moving components and products through plants. There are two main types of conveying systems; floor conveyors and overhead conveyors.
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.
Belt Conveyors are the most commonly used in bulk handling. 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.
Today, conveyor is driven with an electrical motor through gear reduction, in the earlier times, it was driven by water power, animal power or even manually. This type of conveyor system dates back at least several centuries and was originally used to move grains and flour through mills.
