A metal coupler is a device used to join two objects. It may consist of a range of different materials, from steel and aluminum to brass or copper. These devices may be as simple as metal sleeves used to join two or more pieces of fabric, or as complex as a hitch found on a railcar or piece of construction equipment. Different types of couplers, also known as couplings, should be chosen based on their size, strength and proposed function to ensure they will meet the demands of each project.
The simplest metal coupler units utilize a simple compression or clamp design. Once they are in place, force is applied to the outside of the coupler, which causes it to grip the object within using compressive strength. Similar bar or beam metal coupler designs can be used to join two small shafts within a machine. Some of these beam style couplers use a screw-on mechanism rather than compression to hold them in place. This type of beam or bar design is appropriate only for relatively simple applications that require minimal holding force.
Railcars and heavy equipment often relies on a heavy-duty metal coupler to join multiple cars or units together. For example, classic railcars rely on a hook and pin coupler made of heavy iron, or a hook that connects to a series of steel or iron chain links. These couplers were once used to allow workers to connect and disconnect railcars with relative ease. This type of metal coupler is still widely used today in modern construction equipment. For example, cranes may incorporate a hook and pin style coupler for rapid fastening and unfastening by work crews. The same principle apples to ball and hitch style designs and other rapid hitch type of couplers.
More complex applications require intricate metal coupler designs. These advanced models often allow one or both components to flex or move once they are connected. An example of this is the gear or disc coupler, which joins two components using a series of interlocking teeth and a protective metal sleeve. Bellows joints are similar, and consist of an accordion style design that allows the joint to flex and move while transferring motion between the two objects. Even a chain and sprocket can be considered a type of metal coupler. In this example, a metal chain connected to one shaft or engine would join with a sprocket connected to a separate shaft or engine, and transfer momentum or energy between the two.
