1.1 What is a Chain?
A chain is a reliable machine component, which transmits power by means of tensile forces, and is used primarily for power transmission and conveyance systems. The function and uses of chain are similar to a belt. There are many kinds of chain. It is convenient to sort types of chain by either material of composition or method of construction.
We can sort chains into five types:
- Cast iron chain
- Cast steel chain
- Forged chain
- Steel chain
- Plastic chain
Demand for the first three chain types is now decreasing; they are only used in some special situations. For example, cast iron chain is part of water-treatment equipment; forged chain is used in overhead conveyors for automobile factories.
In this book, we are going to focus on the latter two: "steel chain," especially the type called "roller chain," which makes up the largest share of chains being produced, and "plastic chain." For the most part, we will refer to "roller chain" simply as "chain."
NOTE: Roller chain is a chain that has an inner plate, outer plate, pin, bushing, and roller.
In the following section of this book, we will sort chains according to their uses, which can be broadly divided into six types:
- Power transmission chain
- Small pitch conveyor chain
- Precision conveyor chain
- Top chain
- Free flow chain
- Large pitch conveyor chain
The first one is used for power transmission, the other five are used for conveyance. In the Applications section of this book, we will describe the uses and features of each chain type by following the above classification.
In the following section, we will explain the composition of power transmission chain, small pitch chain, and large pitch conveyor chain. Because there are special features in the composition of precision conveyor chain, top chain, and free flow chain, check the appropriate pages in the Applications section about these features.