Chain Shapes and Styles

Chain Shapes and Styles

Regardless of whether the chain is roller chain, toothed chain, engineering steel chain or flat top chain, their shapes can be divided as follows:

1) Straight (chain) plate chain. The chains are made up of alternating inner and outer links. They include roller chains and roller-less chains similar to roller chains.

Chain Overvi teel (engineering and traction) chains, which are also without rollers. Other technical reasons.

These differences in shape and detail are important to both the manufacturer and the user, not only in terms of cost, but also

Obviously, it is very likely that there is a mixture of the above-mentioned types of chain. In any case, in general there are far fewer curved chains than straight chains, and more roller chains than rollerless chains.

1. The shape of the tensile elements of curved and straight chains (in this case both sides of the chain plate, they are both engineering steel chain plates) is the only structural difference between these two types of chain. They have the same pitch and hinge, the same cross-section of the chain plates, the only difference is between the curved and straight chain plates, so that both chains can work on the same sprockets and fulfil the same purpose. But they cannot be "mixed".

Splicing high points:

Splicing into chains, unless the manufacturer explicitly authorises this.

Typical curved and straight chains

A straight chain consists of two links, inner and outer, whereas a curved chain consists of only one link, and there are differences in the use of these two different constructions. According to the construction, a straight chain without a transitional connecting link is necessarily only available with an even number of links. In contrast

In comparison

the number of links in a bent plate chain can be either an even or an odd number.

The number of links in a chain can be either even or odd. A straight plate chain can work in both forward and directions, but a bent roller chain with composite transition links should be driven in a specific direction (distinguishing between running with the narrow end facing forward and the wide end facing forward). The direction of operation of the bent plate chain has to be determined according to the application and the product description has to be observed. Details of the direction of transmission will be discussed later.

Each type has its own advantages. Straight plate chains are easy to manufacture and have a price advantage. Straight chains are designed to be easier to fit with accessories and cause fewer problems in use. For a given strength, a straight chain with a slightly smaller pitch can be used if there is insufficient space to fit a curved plate chain. Although the chain plate thickness and cross section are similar, the pitch of a straight drive chain can be relatively small. Smaller pitch in the drive means smaller sprockets and less noise in operation.

One of the advantages of a bent plate chain is that the chain can easily be shortened by removing a link and shortening the worn and elongated chain. To shorten a straight chain with connecting links, a pair of links (an inner link and an outer link) has to be removed and replaced by a transition link. If the straight chain does not have connecting links, then a section of chain with five links must be removed first, which consists of two inner links and three outer links. The middle three links are replaced by a two link composite transition link and the remaining two outer links are replaced by two link links. After this batch change, the chain bending should also be carefully checked to see if the chain plate of the transition link is obstructing the end of the adjacent straight link when it is bent.

Some applications, such as bucket elevators or conveyors, mostly use rollerless chains, where a bent plate chain with the wide ends of the links facing forward in the installation will give a good service life. Such users should carefully follow the manufacturer's recommendations.

2、Roller and rollerless chains

As a user, the interest in choosing a chain with or without rollers is probably much greater than whether to choose a straight or curved chain. The main purpose of using rollers is to reduce friction, but there are two independent functions of rollers in a chain, both of which are achieved by the same roller, they are:

1) Engaging with the sprocket teeth and transmitting the sliding function to the internal elements of the chain, both of which are designed for their purpose. This will also be discussed in subsequent chapters.

2) act as guides and support for the chain and for carrying items when running in rails or guide channels, and as such are characteristic of conveyors and some bucket elevators.

The rollers of the drive chain, whose diameter is generally smaller than the height of the chain's chain plates, are shown in Figure 2-3. Therefore, the chain plate acts as a guide when the chain engages with the sprocket, which is the same as the chain plate that rides on the rail in a bucket elevator.

The diameter of the conveyor chain rollers is generally much larger than the height of the chain plates for two reasons: The most obvious reason is that the large rollers - also known as carrier rollers - keep the chain plates on both sides above the conveyor track and thus avoid wear. In addition, the mechanical advantage of the larger rollers over the smaller rollers in terms of rolling friction helps to reduce chain tension. This is discussed in more detail in chapter 9.

In most chains the carrier rollers are also used for engagement with the sprockets, however, in some cases the carrier rollers are fitted with wear reducing bearings and are used as external rollers on rollerless chains.

Rollerless chains are similar in appearance to roller chains in that they are used where rollers are not required and most rollerless chains are engineering steel chains. There are also other types of chain without rollers, as they are clearly not suitable for use with rollers, such as block chains, toothed chains and flat top chains.

The various types of chains, their construction details and applications are described below. The designer can also consult the corresponding ASME standards and manufacturers' catalogues for more detailed information, including dimensions, working loads and other data.