The mechanical structural joints They are widely used, primarily in the construction and industrial engineering sectors. We are referring to those used to join two load-bearing components in order to transfer a heavy load from one to the other. Depending on the system used and its characteristics, there are several different types.
Rigid and Movable Joints
The first major classification we can make has to do with the ability to move, rotate, or shift of any of the structural members that remain juxtaposed. In the case of rigid joints, we do not consider any of these options, unlike with flexible joints.
Classification of the Different Types of Rigid Joints
In turn, when we talk about rigid joints, we can divide them into two main groups: fixed and removable. Each one offers several options, which we'll describe in detail below:
- Fixed Joints. Those for which we use rivets or fasteners made of materials such as mild steel, copper, aluminum, or steel. It all depends on the structures we need to join and the desired strength.
- Permanent Welded Joints. We use heat input, either directly or by adding another metal with a composition similar to that of the structures to be joined. The different types of welding include pressure welding, fusion welding, arc welding, manual electric welding, semi-automatic or automatic electric welding, automatic electric welding, and resistance welding.
- Fixed Nailed Joints. These are the joints we use primarily to join boards and other structural frameworks made of solid wood. To create them, we can use nails, bolts, plates, or rods.
- Screw-type detachable joints. We typically use them on steel plates, and they consist of a washer and a nut used to tighten or loosen the screws.
- Detachable, notched joints. They are commonly used to connect machine parts with shafts that must perform precise rotational movements. They are detachable, and we use keyways for this purpose. Depending on the function of this component, we distinguish between sliding keyway connections, interference fit connections, and profiled shaft connections.
- Detachable joints with pins. They fit precisely into pre-drilled holes, which transfer forces perpendicular to the pin's axis. They are usually made of steel, with or without a head. They are primarily used to join individual parts.
Different Types of Movable Joints
For these connections, we use complete parts, parts of components, or subassemblies that serve to restrict certain movements and facilitate others. We can distinguish three main types:
- Rotary Joints. A very clear example is the pulley, a mechanical lifting or pulling device consisting of a wheel or pulley mounted on a shaft and a rope wrapped around its circumference.
- Sliding Movable Joints. These are joints in which one of the two parts to be joined is fixed and the other slides through it, either with lubricant or with the aid of another component. For example, leaf springs or coil springs.
- Flexible Movable Joints. There are various types of mechanical structural joints, depending on our specific needs. These joints can be disassembled without using destructive methods.
In addition to the ones we've already mentioned, there are other resources you can use to create mechanical joints, such as the structural adhesives. In this case, their main advantages are that they allow us to save a considerable amount of time and money, provide an attractive finish, and greatly simplify the processes.
Professionals in these sectors of construction and industrial engineering must have the necessary training to perform their duties, including in the area of joints. In this regard, we recommend the master's programs in Structuralia in construction, such as the Master's Degree in Structural Analysis or the Master's Degree in Smart Infrastructure. Smart Cities. Very useful resources for acquiring the essential knowledge in this field.
