An overhead conveyor is an elevated system similar to a floor-level conveyor belt that is used to transport items throughout a facility. Unlike a conveyor belt, which is belt-driven, an overhead conveyor is driven by a chain and is considerably thinner. The trolleys — the units that hold items — are generally rings or hooks, and each can hold a considerable amount of weight. This conveyor can be used in many types of facilities but is especially useful in those that require bends in the conveyor. Such a conveyor makes good use of space, but it may not be good for facilities with heavy loads.
Most conveyor units are belt-driven, meaning a large belt covers the entire conveyor and is responsible for all primary movements. Instead of using a belt, an overhead conveyor makes use of a chain. By using a chain, the overhead conveyor’s rails, or tracks, are much thinner. The chain is less likely than a belt to wear out, which usually results in lower operating costs.
Many types of trolleys have been made for overhead conveyor systems, but the basic trolleys are rings and hooks. Hangers and basket units are fairly common but are generally for specialized purposes. This makes the overhead conveyor a versatile system that can be converted to hold nearly any item. Most trolleys can hold from 10 to 100 pounds (4.5 to 45 kilograms), but specialized trolleys can hold much more.
The elevated conveyor’s rails can be easily curved, so this conveyor is typically used in facilities that require a lot of twisting and turning before the item reaches its destination. This is because the rail can be warped to any angle during the manufacturing process. The chain can be easily threaded through the curved rails, while a belt would require considerably more work to curve.
Another advantage to using an overhead trolley is that it makes efficient use of space. A conveyor belt is bolted to the ground, so nothing else can be placed there. With an overhead conveyor, the conveyor can be raised high enough in some areas so workers can walk under the conveyor. Even if this is impossible because of the facility’s ceiling height, it still leaves room on the floor for extra hardware and machines that otherwise might not fit. A disadvantage to this conveyor is that, while it can hold considerable weight, conveyor belts can typically hold more; a facility handling very heavy items may not be able to use an overhead conveyor.