Blind rivets

The greatest market potential among the different types of rivets is forecast for bUnd rivets. Access to the workpieces being joined is required from only one side, thereby offering the ideal conditions for automation. A bhnd riveter for industrial robots has been developed based on a standard tool that, apart from its size and weight, is also notable for its enhanced flexibility. With the aid of a changeover device, for example, different rivet diameters and types of blind rivet can be handled. 

Riveting is one of the classical joining processes. It is in particularly wide use in the aircraft industry. What all rivet methods have in common is that an auxiliary joining part, the rivet, must be provided. Blind rivets are often used in device assembly because accessibility firom one side is sufficient. 

Blind rivets, also known as pop rivets, are rivets which can be set when access is limited to one side of the assembly. However, they are also widely used where both sides of the assembly are accessible. 

Used to join sheet metal, blind rivets are readily available in sizes up to around 5 mm diameter and 12 mm long in aluminium, steel and monel. Plated steel rivets are used where low cost, relatively high strength and no special corrosion-resistance is required aluminium for greater resistance to atmospheric and chemical corrosion and monel for high strength and high resistance to corrosion. 

Blind rivets consist of a headed hollow body inside of which is assembied a centre pin or mandrel. The rivet is set by inserting the mandrei in a tool having a means of gripping, and the rivet is inserted into a predrilled hole in the assembly. Operation of the tooi causes its gripping jaws to draw the mandrel into the rivet, with the result that the head of the mandrel forms a head on the rivet on the blind side of the assembly, at the same time pulling the metal sheets together. When the joint is tight, the mandrel breaks at a predetermined load. Fig. 12.13. The broken-off portion of the mandrel is then ejected from the tool. 

Blind rivets with controlled shank expansion. 

Blind rivets consist of a headed hollow body inside of which is assembled a centre pin or mandrel. 

Blind rivets located into a previously created hole in the assembly from a single direction using a special tool. The tool retracts a headed pin from the rivet body deforming it enough to hold the components. The head is left inside the rivet body on joint completion. Used for thin sheet material fabrication. 

Figure 12.5. Types of nut (a) wing (b) dome or acorn (c) rivet bush or nut(d) blind (e) flat spring steel fastener and (f) J type fastener...

Where thin sheets are to be joined and access is availabie from only one side, rivet bushes or rivet nuts are used. These provide an adequate length and strength of thread which is fixed and therefore allows ease of assembly, Fig. 12.5(c). Available in thread sizes up to 12 mm for lighter applications, blind nuts of the type shown in Fig. 12.5(d) can also be used. The nut is enclosed in a plastics body which is pressed into a predrilled hole. A screw inserted into the nut pulls it up and, in so doing, expands and traps the plastics body. 

Composites are mechanically fastened in a manner similar to metals. Parts are drilled, countersunk, and joined with a fastener. Rivets, pins, two-piece bolts, and blind fasteners made of titanium, stainless steel, and aluminum are all used for composites. Several factors should be considered ... 

Plastics self-expanding rivets. One piece self-expanding blind plastics rivets are normally made of nylon (Fig. 4), although most thermoplastics including polyethylene, polypropylene, acetal and polystyrene can be used. The... 

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