Rivets

Rivets are permanent mechanical fastener. Their structure consists of a cylindrical shaft with a head on one end. The figure 1 shows an example. 

They have a good resistance to shear strength, but they're fragile when subjected to traction. They're used in structural bonds and industrial bonds.

• Structural bonds: used in high resistence. Ex: automotive industry, aeronautical industry, civil engineering.
• Industrial Bonds: used in low resistence. Ex: Utensils, in furniture, commercial machines etc.

Rivets are used when it’s not possible to weld or its use is very expensive if compared to rivets.

Figure 1:  Round-head rivet

Source: Elementos de máquina-1-

Applications of rivets

• Fixing the friction cloth tips of the clutch disc of a car;
• Fixing bridge structures;
• Fixing ship window;
• Fixing airplane structure.

Rivet Advantagens

• Cheaper;
• Rivets don’t change ownership of the materials; 
• Prevent cracks caused by material fatigue;
• Rivets don’t distort the material;
• Vibrations don’t loosen the rivets;
• Their installation is very easy.

 Rivet Disavantagens 

• The structure is not dismountable; 
• Make the structures havier;
• Weaken the material because of te holes made in their installation.

 Rivet Material 

The rivets can be made of any ductile material, whose resistence to shear strenght is good enough for the application. The steel rivets with medium and low carbon are cheap, have a good reistence and a good ductility. The aluminum rivets are used in aeronautical industry, in consumer products. Their application depends on their quantity of aluminium. 

Rivets can also be made of brass, copper alloy and stainless steel.

Rivet Types

The figure 2 shows some examples of rivet types.  It’s very importante to know the best type of rivet to use, once there’re several ones.

   Other exemples of rivets are: explosion rivets, tube rivets etc.

Figure 2: Examples of some rivets

Source: Elementos de máquina-1-

Manufacturing Standards

The rivets manufacturing obey technical rules. These rules establish the measure of the rivet head and the rivet shaft, as shown in Figure 3.

In figure 3, “d” represents the diameter of rivet shaft, and the measure of  rivet head depends on “d”.

Figure 3: Measure of some rivets

Source: Elementos de máquina-1-

Useful Length

The rivet useful length is the part of rivet shaft that will stay between the plates, as shown in Figure 4. In this case, “L” represents the useful lenght.

“Z” is the left over. This is the part that will become a new rivet head.

Figure 4: Useful lenght

Source: Elementos de máquina-1-

Bibliography

COLLINS, Jack. Projeto de elementos de máquina: uma perspectiva de prevenção da falha. 1. ed. Rio de Janeiro: LTC, 2006. 740 p.

PROFISSIONALIZANTE: mecânica : elementos de máquinas - aulas de 1 a 20 [recurso eletrônico]. Rio de Janeiro: [s.n.] (Telecurso 2000 profissionalizante). 

Posted by: Fellipe Lopez.