Conveyors are the most popular solution for material handling in warehouses and on assembly lines. A gravity conveyor relies on a slight incline in order to move packages across the facility and to overcome resistance. The tracks are fitted with metal rollers and ball bearings so that a bin, box or part will travel a very long distance without requiring any external power source. Distribution centers or other facilities that are installing gravity conveyors or integrating the units into an existing design should consider several important factors before using the equipment for the first time.
A gravity conveyor has a very small footprint when compared to other types of units. The frame is relatively light and has large areas of open space underneath. This makes it easy to position the unit in a busy location without restricting access to an aisle or bins on the floor. Each section of track should be positioned close to a picking location or down the side of an aisle if possible. Long lines can be run down open areas and fed from individual aisles by branching conveyors. Another option is to create layers of conveyors on different levels. This will allow sorting or the movement of materials from a single source to multiple endpoints.
The height of each gravity conveyor should be carefully chosen based on the use of the unit. Selecting the correct height will allow employees to move materials and handle parts without bending down or assuming a position that is uncomfortable or dangerous. The correct height will also make it easier to move heavy items from a shelf to the bed. The height should be determined by the movements of workers and the location of the items that will be processed on the conveyor.
A gravity conveyor must be kept at a slight angle in order to move parts and packages down the line. Many units have a way to adjust the grade of the bed. The grade should be carefully calculated so that materials move smoothly down the line without accelerating so much that damage could be caused when a processing point is reached. A number of formulas are used to determine the grade of a gravity conveyor, based on the average size and weight of a package, as well as the length of the line.
A gravity conveyor uses metal rollers to support and move materials. Some designs allow the spacing between rollers to be adjusted or selected when the unit is first purchased. The spacing is very important because it will determine what types of objects can be moved efficiently across the bed. The general rule is that all packages or parts need to have contact with three rollers at all times. This means that the spacing should be adjusted so that the smallest part or product will touch three rollers simultaneously. Spacing that is too wide could cause products to move slowly or to bounce unnecessarily.