Riveting process
The riveting process or riveting is a manufacturing process from the group joining by forming , which includes the production of a riveted connection . When riveting, the auxiliary joining part, the ( or the) rivet (the rivet), is plastically deformed at a connecting hole. Riveting is a joining process , especially for sheet metal and similar low-strength semi-finished products .
An industrially manufactured rivet usually has a prefabricated setting head at one end. At the other end, a locking head is made with various riveting tools in order to close a riveted joint.
This article explains the processing of traditional solid rivets . For the use of blind and other rivets, see: Rivet # Procedure .
Support on counter holder and riveting pads
At the beginning of the production of a closing head, the rivets are inserted through the rivet holes of the components to be connected.
It is important that rivets with the correct diameter and the correct shaft length are used or that rivets with longer shafts are shortened accordingly (pliers, bolt cutters, etc.). The rule of thumb for the correct length for upsetting a semicircular closing head is:
Shank length = total thickness of the materials to be riveted + 1.5 • shank diameter .
That means: If you stick the rivet through the materials to be connected, a piece about one and a half times the diameter of the shaft protrudes on the opposite side.
The components together with the rivet are now placed on a suitable support for subsequent processing, which, depending on the type of rivet head, can consist of a counter holder or a rivet support.
If the rivet has a set head protruding above the material surface (e.g. a semicircular head), counterholders are used, which are preferably clamped in a vice. The setting head rests on the counter holder in a recess that is adapted to its shape. This means that the setting head is not deformed during the subsequent work. (The counter holder can be seen in the illustration below the components.)
In setting heads which are flush with the surface of the workpiece (z. B. lowering and flat head rivets), come Nietunterlagen used. Instead of a hollow, these have a flat surface as a support for the workpiece and a flush rivet head. Riveting pads are also clamped in the vice. Alternatively, you can use an anvil or a rivet bar instead of a rivet pad.
Pulling in the rivet with the rivet puller / rivet puller
A rivet puller is sometimes referred to as a rivet puller .
Before being drawn in, the individual parts to be connected lie loosely on top of one another on the counter holder or on the rivet support. In doing so, they usually do not have flat contact with one another, because the workpieces are curved or the burrs on the drill hole leave an irregular distance. The Nietzieher is by hand or by a riveting machine on the plugged-through rivet pushed to the hole edges before upsetting the closing head pushed firmly together. With manual riveting, pressing is done by hitting the rivet puller with a hammer. Any bulges are expressed and if the rivet is tight (e.g. due to imprecise holes) the parts are brought into contact and the rivet is pushed completely into the hole. (The rivet puller can be seen in the illustration above the components.)
The central cylindrical bore of the rivet puller is larger than the diameter of the rivet shaft , so that the rivet and rivet puller do not in principle touch. This prevents unwanted deformations of the rivet shank prior to upsetting.
The rivet puller ensures that the workpieces lie flat together, but the pressed flat parts can also slide apart again. Suitable measures should be taken to ensure that the individual parts are held together after removing the rivet puller and before upsetting the rivet. For example, by pressing the components together next to the riveting point with a screw clamp .
Compression of the shaft with a hammer
The protruding part of the rivet is compressed by vertical blows with a hammer. The upsetting process makes the rivet wider, fills the rivet hole and presses against the walls of the drill hole. The rivet shaft must not bend as a result of the vertical blows.
Preform the closing head with a hammer
The rivet is then preformed with the hammer track to an approximately semicircular shape, which roughly corresponds to that of the closing head. For this purpose, short blows are made on the rivet head from all sides. (The hammer is thus guided around the rivet head in conical circular movements.)
Final shaping by the rivet head setter
Finally, the rivet head setter is used, which gives the closing head its final shape. Alternative names of this tool are anvil , Nietkopfmacher (short head maker ), closing head shaper , Nietkopfformer or Koeppel makers .
The rivet head setter is placed on the preformed rivet and the closing head is brought into its final shape by hitting it with a hammer. If possible, notches in the workpiece surface should be avoided.
Hot riveting and cold riveting
In the construction of ships, bridges, boilers and high-rise buildings, large rivets with a diameter of more than 6 mm are riveted "warm", that is, in a red-hot state. The subsequent cooling causes the rivet to shrink, whereby the sheet metal plates or steel profiles are pressed together frictionally and watertight.
Three people are required for this process. The rivet heater heats the rivet and passes or throws it to the second person, the counter holder. It is thrown into a tin catcher . The counter holder pushes the warm rivet through the rivet hole with pliers and presses the head into place with the setting iron. The actual riveter on the other side strikes the rivet puller and finally works the other head with a hammer and a second setting iron.
Smaller and especially copper rivets are processed cold, but these too heat up due to the impact effect and pull the riveted parts together as they cool.
literature
- Expertise for metalworking professions , Europa-Lehrmittel OHG, Verlag Willing & Co, Wuppertal-Barmen 1962.
- Roloff / Matek: Machine elements table book , Vieweg Verlag, 18th edition 2007, ISBN 3-834-80262-X .
Web links
- Photos of the construction of the Schleibrücke in Kappeln 1925 - 1927, including illustrated explanations of the riveting process . Archive of the city of Kappeln, accessed on September 9, 2016
Individual evidence
- ↑ Metal table book, Europa-Lehrmittel OHG, Verlag Willing & Co, Wuppertal-Barmen 1962.
- ↑ Roloff / Mattek: Machine elements , 22nd edition, p. 200.
- ^ Alfred Hölder: The work settings and lockouts in commercial enterprises in Austria. Volumes 15-17. Statistical Department in the KK Ministry of Commerce (Ed.), 1910 ( p. 63 partly online at Google Books.)
- ↑ The work of the rivet heater was monotonous and often dangerous. He had to pay a fine for burnt rivets or incorrect throwing. Source: Excerpt from the factory regulations of the Flensburg shipbuilding company. In: Neuer Social-Demokratie, organ of the Socialist Workers' Party of Germany. May 13, 1874 ( online at Google Books ). Retrieved September 9, 2016