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Nippon Conveyor Pulley


In Belt Conveyors, if we only look at the number being used, pulleys are used in a small number, but in the operation of a conveyor belt system, it plays a very important role.

Just a minimal damage on a certain pulley may easily lead to inoperative cause of a system, and the non-operation of the conveyor, if it is the middle line of a plant, adversely affects the overall plant.

In addition, pulleys are likely to be considered less important as they are simple structure-wise. However, as they rotate under substantial internal stress, a breakage can easily take place if there is any defect of shortage of strength on one of the components of pulley.


Nippon Conveyor Co., Ltd., a speciality manufacturer of the belt conveyor systems, have been designing and supplying, on world-wide basis, a variety of belt conveyor systems including heavy-duty and long-distance conveyors to such industries as steel making, earth-moving and reclamation, electric power generation, chemical and cement production fields.

With this long period of experience and R&D work, Nippon Conveyor has also been supplying a lot of reliable pulleys meeting the requirements for conveyor pulleys under up-dated designing, manufacturing technology and quality-control certified by ISO 9001.

1. Pulley Structure

A pulley consists of a shell, end discs, hubs and shaft, and a wide variety of types are available by changing the machining work employed, the welding process for assembly and shaft-fitting to meet any requirements against load

2. Pulley Types

The type of Pulley to be employed varies with the load (belt tension) and the belt width, as shown in Table 1.

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Types of NC Pulley_edited.jpg

3. Pulley Structure Analysis

A pulley assembled by means of welding consists of a shell, end discs, and a shaft, and the analysis of the stress given on each component shows that stress on each differs respectively with the belt tension, the wrap angle, and the rigidity of the material of the element.
When belt tension applies to the pulley consisting of a shell, end discs, and shaft, each part of the pulley is displaced. The structural analysis of this displacement constitutes the calculation of the strength of each part of the pulley.


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4. Accuracy of Pulley

1. Pulley Classification
Pulleys can be classified into 2 grades A and B according to the difference in outside diameters and the runout on the outside diameter.


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2. Tolerances on Pulley diameter
The tolerances on the pulley diameter are shown in Table 3 in accordance with the pulley diameter.


Tolerance of NC Pulley Diameter.png

Remark: The tolerance for the lagged pulley is available by adding 1mm each to the value of Table 3

3. Runout on Outside Diameter
The permissible value of runouts on outside diameters for pulleys of grade A is shown in Table 4. In accordance with pulley diameter.


Run out on outside diameter NC pulley.png

The tolerance for the lagged pulley applies to the lagging outside diameter and is obtainable by adding O.5 mm each to the values of Table 4.


4. Pulley Balance
Grade A drive pulley for 3.33m/sec. and a belt width so adjusted as to have it with JIS B 0905, G40.

5. Pulley Inspection
The inspection shall be carried out according to the grades of the pulleys respectively on the items in Table 5.


Pulley Inspection NC pulley.png

5. Lagging of drive pulley

Lagging of NC drive pulleys.png