Rivet

The or the rivet ( rivet plural ) or the rivets ( the rivets plural ) is a plastically deformable, cylindrical connecting member. Riveted joints are mainly used for the joining of sheet metal parts.

By Kaltnietung a form-fitting riveted joint is made of two components. In addition Warmnietung created during cooling of the rivet by shrinking a force fit.

Rivets are made of steel, copper, brass, aluminum alloys, plastic, and titanium.

For producing a riveted see riveting process.

• 4.3.1 with solid rivet
• 4.3.2 with semi-hollow rivet

Etymology

The word is derived from the Old High German word rivet ( " fix " ) hniutan. In Middle High German rivet is also available for a wide beaten nail.

The word is common in several forms and genera:

• Specialist terminology of the rivet, the rivet Pl; FM Feldhaus held in 1914, however, nor the shape of the rivet to be correct.
• General language, Austrian, Swiss German and South German often: the rivets, the rivets.

Both forms mingle increasingly. One finds DIN standards on " rivets ", also ÖNORMEN on plural " rivets ".

General

In the components to be connected must be brought holes that have a slightly larger diameter than the rivet. By these components, the rivet is pushed so that it is also above. Subsequently, the projecting end of the rivet is formed by machining with a hammer to a head ( the so-called closed head), which connects the components securely. The closing head the opposite part of the rivet setting head is called, the part between the rivet shank.

Rivets offer advantages over screw the advantage that none of the components in a thread has to be introduced. A disadvantage is that the compound is not a non-destructive to solve. However, this disadvantage in some areas, the main advantage of this joining technology - precisely where it comes to permanent connections. This includes the aircraft, at the riveted joints are an essential basis of the structural components. In contrast to threaded connections, which must be verified by measurements complex (torque and the like), a form-locking rivet can be recognized visually and no measuring effort at the closing head formed.

A rivet is a cylindrical (excluding special shapes) bolts of metal, of a thickened end - the head - has. Depending on the application different head shapes are processed, for example, half-round, countersunk, flat round and Flachsenkkopf. The rivet lying with his head on one side of the workpieces to be joined. The shaft is inserted through the pre-drilled or pre-punched hole and deformed by pressure in width, so that the workpieces are firmly connected. The pressure can be applied by impact or continuously, for example by a hydraulic press suddenly. Rivets with a diameter of more than 8 mm are beaten warm, that is in the forge on yellow heat heated, stamped and shaped the glowing head. Upon cooling, the rivet shrinks and clamps the workpieces to be joined. Thus, a distinction is made between cold and Warmnietverbindungen.

Importance

The classic solid rivet connection is often replaced in technical applications today through the welded joint. Riveted is only there, where welding is not suitable such as in lightweight or non-weldable materials, as well as in the repair of old riveted joints.

Reasons for this may include:

• To be riveted components must be superimposed and pierced together, otherwise the rivet not fit due to manufacturing tolerances. If necessary, the hole with a drill bit or a reamer must be reworked. This method is cumbersome and more expensive than automated bonding or welding. Also bolted connections are cheaper to process than conventional rivets. On blind rivets but this is not true.
• Each rivet has to be tested individually.
• By riveting, the force flow is redirected, there arises an additional bending moment in the component. Bumped welds do not have this disadvantage.

The additional bending moment can only be lifted by more elaborate, more sleek compounds ( opposite).

• Compared to linear compounds produced in thin sheets in the region of the rivet hole selectively a high voltage.
• Depending on the materials used are riveted joints susceptible to corrosion. A Abrosten the components to be connected, or rivet heads can lead to a loosening of the connection.

Method

Conventional riveting are:

• Rivets
• Blind rivets
• Punch rivets

Rivets

The oldest connection technology is the riveting by rivets. The origins of riveting with solid rivets can be traced back to the Bronze Age. However, this connection method has important features, which still makes them today in safety-critical connections irreplaceable. This includes not only steel structures for buildings, especially the aircraft. Even the most modern aircraft are still made by the riveting of sheet metal structures with solid rivets.

The most important reason for the use of solid rivets is the simple production of riveted joints and the fact that the quality of the connection can be tested by simply viewing without tools. This is probably the most important reason why in safety-critical applications that are subjected to high fatigue load, rivets are used. The secure position of the link is purely visual check by the form of expression of the rivet head.

On aircraft, in which the structure is secured by riveting of thousands, thus to easily check the connection quality is possible. Furthermore, the resistance of a Vollnietverbindung is superior to any other joining method in fatigue loading. For example, from 1937, built by Dornier aircraft ( DO24 ATT ) is still in flight use today.

According to the shape of the head, these rivets are also called snap rivet and countersunk rivet.

Semitubular

The semitubular rivet corresponds to the solid rivet, but has a one side open end is expanded or crimped by a mandrel, instead of being formed into a head.

Hollow rivet

A hollow rivet is a sleeve, which is often already has a single-sided molded collar or a closed head.

Open ends are expanded upon compression of the rivet with specially shaped Nietsetzern or corresponding tongs and rolled over towards the material to be connected to the outside.

Hollow rivets are less resilient and are also used for decorative purposes (eg on a belt ) or to gain hole in paper and cardboard.

Some hollow rivets are closed on one side and, on the opposite side with a rivet cap, so that to see after upsetting no more opening.

Schließringniet ( lockbolts )

After insertion of the base body and the pressing together of the components to be connected, a ring is formed around the projecting end of the slotted rivet. This makes it possible to increase the strength of the connection is still, as the rivet itself is not deformed, and therefore may be made of hardened material.

Blind rivets

A blind rivet is also called Zugdornniet. It is a special form of hollow rivet that requires only access to one side of the components to be joined and fastened with a special riveting tool. The blind rivet consists, besides the actual, hollow rivet body with head on the front of a longer, fitted through the mandrel head at the rear rivet which is provided with a predetermined breaking point.

When blind rivets of the joining operation is performed from only one (usually the outer) side of the component. The blind rivet is inserted through the bore, is pressed by pressing on the head of the components to be connected together, followed by the protruding head mandrel is drawn out with a riveting tool. This leads to a compression and therefore a widening of the rivet past the hole. In the first phase of the compression of the hollow rivet body shortens. This increases the diameter. At the end of the first phase, the hole is completely filled by the rivet. Only when the blind rivet can not expand in diameter, is formed behind the bore appreciable expansion. At the end of the process, the mandrel breaks off at the predetermined breaking point within the rivet body and not protruded out of the rivet; the rest of the mandrel is then in the pliers and is discarded. For blind rivets for special applications ( aircraft, etc.) remaining in the rivet mandrel rest is secured with a pressed- in processing ring. This means that no parts can come loose and the higher shear strength of the mandrel material can be fully utilized.

Typical diameters of blind rivets are 2.4 mm, 3.2 mm, 4 mm and 4.8 mm.

Colloquially, the blind rivet is also referred to as a POP rivet, which is due to the brand of the first POP manufacturer Emhart Teknologies. The POP rivet was introduced in Germany by the company Gebr Titgemeyer GmbH & Co. KG, Osnabrück in the 1950s. The launch of POP blind rivets in Switzerland was carried out by the KVT- Koenig AG.

Special shapes:

• Hammer - blind rivet. Here, the mandrel is not drawn, but taken to spread the rivet. The mandrel remains in the rivet and closes the opening. They are made of plastic.
• Becherniet ( sealing rivet ). The thickened end of the mandrel is not visible here because it is the body of the rivet ( like a cup) completely surrounded.
• Sprengniet. The expansion is performed here by a small explosive charge.
• Pull-through. The mandrel has no predetermined breaking point, in this variant, and is pulled completely through the rivet therethrough. The mandrel has a hexagonal head and a thread is impressed in the outer surface of the rivet, the rivet can be removed subsequently by using a hexagonal wrench. This embodiment can be obtained with nominal diameters of 3-4 mm
• Durchzugsniet FSR. For applications in confined space of Senkkopfniet allows both sides flush setting. The rivet in the microformat is therefore the ideal solution for the electronics industry. The passage of the mandrel ensures that there is still a blind side head supernatant after setting neither loose residual mandrel heads.
• Stufenblindniet ( Stufenniet ). The hollow rivet body is made of a thinner region which behaves like a blind rivet. Between this and the head is a region of larger diameter which does not shrinks or expands. Stages blind rivets are used when there is a little harsh, hollow or sensitive to pressure in the surface of the components to be connected.
• Blind rivet bolts and nuts are suitable to equip components with small wall thickness threads. Blind rivet nuts are sleeves having a collar at one end an internal thread and at the opposite end. The shaft has between the threaded collar and a lower wall thickness. Setting tool as a screw or threaded bolt, instead of the mandrel is screwed, which the thin-walled shank bulge outwardly upon tightening, so that the blind rivet nut is braced with the support material.
• In the blind rivet mandrel of the ordinary Blinniet is replaced by a fixed to studs. To set the rivet threaded bolt is tightened until braced the rivet.

Rivet

The aim of the punch riveting is the indirect, non-detachable joining of sheet metal parts, without the usual solid rivets or blind rivets necessary pre-punching. To this end a rivet element ( auxiliary joining part ) is used, which also functions as a stamp. Depending on the rivet used are basically two punch rivets of importance: Riveting Rivet or Riveting semitubular. Common to both methods is that they require a two-way accessibility of the components, and that the preparation of the compound occurs in a single-stage setting operation.

With solid rivet

Punch riveting with solid rivet the compound is formed in a continuous punching and forming process, in which the rivet itself is not converted. The sheet metal parts to be joined are placed on the die. The upper part of the setting tool then moves into the sheet metal parts to be joined to the bottom. Simultaneously, the concave rivet automatically fed and positioned. By the setting unit, the sheet parts are pre-tensioned. Now the actual riveting presses the rivet through the joining members with two sheets from a circular piece ( slug ) is punched. The processing device for piercing riveting with solid rivet is designed so that it presses the stamp after stamping the parts to be joined a well-defined way ( force or displacement control ) against the resistance of the joining parts down. The plates are pressed with the force required for the manufacturing steps described in the following part of the die. Due to the annular raised structure of the punch and the die, the joining material is plastically deformed. The punch and die- bonding material flows into the shared by the concave shape of the rivet area. This joining is finished. The main requirement for a fixed connection at different loading directions is the piercing riveting with solid rivet the controlled, complete filling of the free space, which is defined by the geometry of the rivet; Only in this way is achieved a force- and form-fitting connection.

It is obtained a high tensile strength. A two-sided almost flush completion is possible. Sheets may have different thicknesses and of different materials. The total sheet thickness is typically 1.8 to 7 mm. Are usual rivets made ​​of stainless steel or aluminum.

With semitubular

Even when punching rivets with semi-hollow rivet the rivet element serves as a one- cut punch. However, it is itself likewise reshaped. The sheet metal parts to be joined are placed on the die. With the placement of the setting unit during the advance, the joint is fixed. With the further advancement, the rivet element of the joint is then supplied. In the subsequent joining process punches the Stanznietelement, unlike the piercing riveting with solid rivet, only the upper sheet metal part by and shapes the lower sheet metal part plastic to a closed head around. The shape of the closing head is essentially determined by the contour of Matrizengravur. After reaching a preset maximum force ( force-controlled ) or a predetermined path ( controlled) the return stroke. The rivet is replaced in the plastically deformed lower sheet metal part with a collar forming his closing head. The punched out of the upper sheet metal part slug fills the hollow rivet shaft and is sealed therein. Achieving a large Anchor expansion of the rivet shank is an important geometric parameter. It has significant influence on the transferable shear and Kopfzugkräfte. Due to the compression of the self-piercing rivet is a high-strength and gap- free, ie reached closer fit of the parts to be joined. In addition, the self-piercing rivet is axially and radially compressed, so that a force fit is inserted into the connection.

The sheet thickness is typically 0.75-2 mm.

Special Procedures

A special form of punch riveting is the hydraulic riveting dance, in which a high-pressure fluid acts as a stamp replacement.

There are also rivets stamped from sheet metal, sublime shaped and can be taken with several sharp spikes in clothing or dog collars, fabric or leather, we distinguish between pyramids, Spitz, killer, Saber and witches rivets; the last are particularly liked wearing in the punk scene on leather jackets. The often inclined conical tips bend during penetration into the material, or standing in line at the inclined surface of a counter- tool, then the curved spikes hold the rivet - in fact by clamping, the application is called rivets because it gives the appearance of a rivet head.

Examination

Ready whipped riveted joints must when struck with a hammer operates not " bounce ", they need to connect the components to play. Prell end rivets are not looked up, but must be completely replaced. Prove to be more than 5 % of all rivets of a component as in need of renovation, so all rivets are replaced.

Load types

Single-shear, double shear or i- shear connection

Stresses and deformations

Nietabstandswahl

Tools

There to close the rivets also special tools, the so-called striker, the, blind rivet or pneumatically betriebenem " Niethammer " and " backstop " is run with tools such as " rivet pliers ".

Constructions

Junction

Point of support

Truss rod pressure

Truss rod pressure

Bridge construction

Nietträger

Eiffel Tower

Example node