Belt meandering and roller machining / Belt conveyor -11

1. Belt meandering and troubles

Meandering means that conveyor belt of a belt conveyor runs by sliding right and left to the moving direction. It is also called deviation.
Because of meandering, the following trouble will occur.
・Edge of belt is damaged by hitting frame.
・Carrying object falls off.
・It takes cost and time to rectify meandering. Object cannot be conveyed during the rectifying period.

2. About meandering prevention by machining rollers

Rollers / pulleys which are parts of belt conveyor can be manufactured to prevent belt meandering as much as possible.
There are two kinds of machining method.

1）Crown machining
Both edges of roller’s steel pipe are scrapped with a slight gradient.
Please imagine upper half of the steel pipe. This is an extreme example but the pipes are scrapped as shapes like ／￣＼. This gradient is generally called crown. Because of this machining process, conveyor belt tends to slide to the middle of belt conveyor while it is running. This crown machining can prevent the belt meandering.
Degree, area and position of gradient for the crown machining differ depend on types of conveyor belts such as rubber belt, resin belt, etc. Degree, area and position of crown machining has close relationship with conveyor belts.

2） V ditch machining
To prevent belt meandering, there are cases that additional parts are attached to back side of conveyor belts along with its all length, one at the center or one for each side edges (=totally two parts). The additional parts are shaped like V belt ＼＿／ and called backside crosspiece or V shaped crosspiece. This backside crosspiece of belt runs along with ditches of roller / pulley and prevents meandering. Rollers / pulleys are grooved to have ditch which fit the backside crosspiece and meandering can be prevented. This ditch is called V ditch.
The size and material of this backside crosspiece is different in rubber belt and resin belt, and there are a lot of different types. Size and material need to be selected based on conveying object, conveying amount per unit time, types of belt, etc. According to the selection of backside crosspiece, V ditch machining will be done on roller / pulley.

The following is a photo of roller after crown and V ditch machining.