About conveying box objects / Belt conveyor -7

Conveyed objects are mainly divided into two groups which are box objects and bulk objects. Types of conveyor differs depends on the types of the conveyed objects.

What is box object?
As its name suggests, box objects mean cardboard boxes, wooden boxes, bags etc. For these objects, belts are flat and objects are carried by just putting on the belts

About conveying boxes
The types of the conveyor belts to convey box objects are selected according to gradient angles of conveyors. A list of gradient angles is below, however, it is just a guide. The gradient angels differ depends on the objects being carried. For example, conveyed object sometimes cannot be move up since it turns over backwards during steep transport in case it is too tall compared with its size. Gradient angles need to be well considered in advance when tall boxes are conveyed with slopes.

About conveyor belt for conveying box objects
There are two types of conveyor belt to be selected as the following. The selection should be done according to objects to be conveyed.
1. Black rubber conveyor belt, for conveying heavy objects
2. Resin conveyor belt, for conveying lightweight objects

1. About black rubber conveyor belt for conveying box objects
There are three kinds of belts.
1) Flat belt, gradient angels is 0°to about 20°
Flat belts can manage these gradient angles. Surface of the belt is flat and there is no special finishing. The length of the belt conveyor gets longer as place to move the object up gets higher. For example, this flat belt is rarely used for purpose to move objects up from the 1^st floor of warehouse to the 2^nd floor. Belt conveyor using belts having special surface finishing which are described in the following 2) and 3) are normally used for this case. It is because cost gets higher and setting space gets larger as length of the belt conveyor gets longer.

2) Rough top belt, The gradient angels is about 20°to 30°
Mesh pattern anti-slip grips are attached on surface of the belts. This type of belt is one of the most frequently used for steep transport of objects. Large space is necessary for flat belt described in 1) above, and belt with cross bar described 3) below is expensive. These may be the reasons.

3) Belt with cross bar, The gradient angles is up to about 45°
Plate-like cross bars are attached on surface of the belt sideways to moving direction. There are various shapes of the cross bars and the shapes are selected according to the object to be conveyed. Objects are conveyed by being caught on the cross bars. Although the gradient angle becomes steep, setting space can be small. However, the price of this belt is more expensive compared with the other two types of belts.

2. Resin conveyor belt for conveying box objects
There are various kinds of resin conveyor belts and the three types described in the black rubber belts above can be found as well. Other than that, vertical grooved belts can be used for the same purpose as rough top belt described in the black rubber belts above. Several grooves are formed in the same direction as objects moving towards. Its gradient angle may be from 20°to 30°.
Other than cross bar belts that projections are attached, there are another type of resin belt which can convey objects with steeper slopes than cross bar belt with only the surface finishing.
It is awesome variety of the resin belts.

3. Relationship between gradient angle and belt speed.
The gradient angle can be made larger when belt speed is slower. Therefore, there is a method which changes belt speed according to types of conveyed objects in case that there are several different types of objects. More objects can be conveyed when speed is faster. However, objects don’t move upwards when moving speed is too fast. Objects can by conveyed efficiently by adjusting moving speed according to types of objects.

The following is a movie of rough top belt conveyors.