In engineering and instrumentation, not only the parts that are used in the production, but also their connections play a very important role. It would seem that everything should be extremely simple, but in fact, if you delve into this topic, you can find that there are a huge number of different compounds, each of which has its own advantages and disadvantages.
In this article, detachable connections will be described - you will learn about exactly what they are, where they are used. They will also be compared with one-piece joints.
At the moment, you can hardly imagine that in general all this means, so do not immediately plunge into not the simplest nuances. Before you consider the detachable connections in detail, you should understand what they are in general, that is, to understand the basic classification of these parts in production.
Classification of compounds
If we take all kinds of compounds, they are divided into two main groups:
It is easy to understand that if the connection belongs to the first group, it means that two parts with it are fastened so that they are static in relation to each other and do not move. They can move as a whole in the mechanism, but they are fastened together tightly.
As for the second group, here we are talking about such a mount, which allows two parts in the process of the mechanism to move relative to each other, while remaining interconnected.
Mobile connections are already divided into detachable and one-piece. The first subgroup describes those that can be opened at any time in any way, while the second group includes those that can only be destroyed - with the use of force, but without the possibility of reconnecting. Most often, such compounds function until they are worn out, after which they are simply replaced.
But the time has come to return to the first large group - the fixed formations. There are also two subgroups here - detachable and one-piece connections. In principle, repeating their description does not make sense, since it remains the same as in the case of mobile joints.
Now that you have familiarized yourself with the basic classification, it's time to focus on the main topic of the article. Plug-in connections will be described as detailed as possible, indicating all the main types that can be found in production.
Threaded connection
Types of detachable joints are numerous, but among them the most famous for all, most likely, will be threaded. Even if you are not working in production, you definitely have ever used a bolt or screw to attach a chair leg or some other part.
This type of connection is characterized by the presence of a thread, which provides fasteners, and, if necessary, the parts can be disconnected - that is why this type also refers to detachable ones. The threaded group can be divided into 2 subgroups that are slightly different from each other:
- One type of such connection may involve the use of two parts, on each of which there is a corresponding thread, whereby bonding occurs. However, this option is not always used.
- In everyday life, you most likely came across the second option, when two parts are fastened together by means of an additional threaded element, such as a bolt, screw or stud.
This species has a lot of advantages - it is considered reliable, is used everywhere, is universal, the parts in it are interchangeable, and it is also high-tech.
But, of course, there are also drawbacks - for example, such a connection in certain conditions can be untwisted, so it must be constantly monitored. Also, the holes for fasteners cause stress concentration in one area, which can lead to overload. Well, of course, such a connection does not provide tightness. All this would be bad if this species was the only one, but, fortunately, there are other types of detachable connections, which we will discuss now.
Pin connection
What other detachable connections are? Photos in thematic books and magazines always show mainly the threaded version, since it is the most popular and widespread. But there is also no less popular - pin. It differs from the previous one in that it has no thread.
A pin is a part that fits snugly into the hole through both parts that you need to fasten. As a result, they remain in one place and securely attached to each other. If it is difficult for you to imagine the described option in mechanical engineering, then you can imagine something more mundane - for example, a visit to the dentist. There are also special pins that are inserted into the gum, and then a seal or crown is baited on them. As you can see, examples of detachable connections can be found in absolutely all areas of life.
Keyway
This is the first type of connection in the list, which is mobile. Most often it is used to transmit rotational motion. How exactly does it function? Installation of detachable connections of this type is quite simple - there is a shaft for transmitting rotation, in which there is a groove where you can insert a key. On the hub, to which the shaft is attached, there is a groove into which the key enters, which ensures the transmission of rotation.
Everything is extremely simple and effective - moreover, it is hardly possible to imagine a connection that is easier to install and dismantle. And even more advantages in the key box adds a low cost. But it is not difficult to guess that the grooves with dowels weaken the overall strength of the entire structure, and also generates an excessive concentration of stresses.
But in general, this connection is also extremely common, and you will find it in many mechanisms. So if you are asked about which connections are detachable, then you can safely call those that you already learned from this article - they are the most popular. But do not think that the listing ends here - ahead of you are waiting for even the most diverse types of compounds that are used everywhere in production and even in everyday life.
Splined connection
A spline connection is also called a gear connection , since the contact and fastening of the parts in it are due to the teeth located along the length of the shaft, while in the part surrounding it there are grooves for all these teeth. The main advantage of this type is its great strength, but special attention should be paid to the fact that with such a connection, the shaft remains able to move along the entire length of the encircling part if necessary. In many ways, these are detachable and one-piece connections. Drawing such fasteners is always quite simple, so everyone can easily deal with it.
Only such a fastening can rarely be found in everyday life, most often it is observed in mechanical engineering and other types of production. The spline connection has a broad classification, which includes the division into groups:
- in the form of teeth;
- according to what kind of load is transmitted through them to the encircling part;
- centering mating parts;
- by mobility, etc.
As you can see, this is one of the clearest examples of the fact that some types of detachable connections can relate to two large groups at once, that is, to mobile and to stationary.
Bayonet connection
You have already learned that a connection is detachable, which allows you to disconnect parts that are fastened together if necessary. The bayonet connection is also detachable and can be found quite often.
It looks unusual - one part has a protrusion, and the other has a special groove in which the protrusion does not just fit, it is attached by pressing and turning, which makes the connection much more durable. The field of application of mounts is very diverse - from mechanical engineering and electronics, to kitchen appliances and cameras. So there is a fairly high probability that you have already come across this option of fasteners.
Terminal connections
Terminal connections are also releasable - they serve to connect the shaft to the hub, but at the same time the process occurs in a rather unusual way. The fact is that the hub has one or two cuts into which a bolt or other fastener is inserted. When it is fixed, the hub is pulled together, tightly pressing against the shaft located inside it. This is a fairly simple connection that is used quite often in many fields of activity.
It is especially worth highlighting the fact that in most cases, such joints used to mount the shaft and hub, such as keyway or spline, allow you to mount parts exclusively coaxially. However, the terminal type allows you to connect them at different angles, as well as mount on any part of the shaft. A drawing of a detachable connection of this type necessarily includes a designation of all these important points.
Cone connection
This type of connection also uses constriction as the main force of attachment, as the previous one. However, this time a slightly different approach is used. The principle of operation is difficult to explain in words, since the hub in this case is a relatively complex mechanism that has several built-in elements that, when the key is rotated in the holes made specifically for this in the hub, narrow the main hole into which the shaft is inserted.
If this explanation does not seem clear to you, then the easiest way is to imagine an old drill with interchangeable drills - this is where such a cone mount is used. You insert a special key, part the fastening elements apart, insert the desired drill bit and fix it by turning the key again. However, such a connection is used not only in drills, but also in many mechanisms in production.
Profile connection
Well, the last popular detachable connection is a profile one. It differs from all previous ones in that it has no keys, no teeth, no thread, or any other fasteners. The fact is that the parts in this case are fixed by combining them with each other so that as a result they form a common inextricable surface. Simply put, they are attached so as to fit snugly against each other, while forming a strong connection.
Its main advantage is the incredible simplicity and complete absence of any third-party elements that cause excessive stress concentration in other types of fasteners. But this type of compound also has its drawbacks, such as high contact stress or a large distribution of force.
Earlier we said that this article will describe the types of detachable and one-piece connections. And although the first ones were mentioned as the main topic of the material, we should still consider the main, most popular, one-piece fasteners.
One-piece connections
There are not many connections that cannot be disconnected with or without using tools. First of all, it is worth noting the welded joint, which is used almost everywhere in production. Everyone can imagine the welding process, for which a special device is used, which greatly warms the metal of both parts at the attachment point. Then, when cooling, this metal mixes, forming a weld that cannot be disconnected just like that - only by destruction.
Another type that functions quite similar to the first is soldering. To create a solder joint, a special device is also needed - a soldering iron. It feeds a special material to the attachment point, and this material has a lower melting point, due to which the parts remain intact, but they are interconnected due to this material. This method is used when the parts cannot be deformed, changed, that is, welding is not suitable for them.
If we are not talking about working with metal, then glued joint is often used - this kind is known to absolutely all people, since you most likely used glue at least once in your life to connect two parts to form a single motionless whole. Exactly the same thing happens in production, only on a much larger scale.
Well and one more integral connection which is worth mentioning is fastening by means of rivets. This species is used quite rarely and was popular earlier. Its essence lies in the fact that pre-prepared fixing materials, called rivets, are also inserted into the holes prepared in the parts. Then the riveting process takes place - the rivets are processed so that they firmly connect the parts to each other, and it was already impossible to separate them. However, you can imagine how costly and time-consuming such a process was. That is why now riveting is rarely used, and rivets in modern times can be seen more often as decorative ornaments on shoes, clothes and so on.
That's all the main types of production connections - both detachable and one-piece. Of course, there are much more of them - especially if we talk about obsolete species, which are now practically not used. There are also those fasteners that are not very common, are used in a specific area and are not particularly popular to be mentioned separately. But we can safely say that even this number of compounds is enough to be able to choose exactly one that would be most suitable for a particular task and give maximum strength and perfect fulfillment of all requirements.