Riveted Join1

Riveted joint:A rivet is a short cyclinderical bar with a head integral to it. The cyclinderical portion of the rivet is called shank or body and lower portion of shank is known as tail. The rivets are use to make permanent fastening between the plates such as in structural works, ship building, bridges, tanks and boiler shell. The riveted joints are used to join parts together permanently. Fastening may be classified into the following two groups. 1) Permanent fastening 2) Temporary fastening

1) Permanent fastening:The permanent fastening are those fastening which cannot be disassembled with out the destroying the connecting component. The example of permanent fastening is welding, braze and riveting joints.

2) Temporary fastening:The temporary fastenings are those fastening which can be disassembled with out destroying the connecting components. For example screws, keys, cotters and pins etc.

Method of riveting joints While connecting plates by rivets the first step is to drill holes in the plates. The rivet is applied by passing its body through the hole in the plate to be connected. The clearance between hole and rivets is 1mm, for rivets up to 24mm diameter and the clearance is 1.5mm for larger diameter of rivets. After inserting the rivet the tail side of the rivet is upset to form is second closing head. This process is called riveting. Best results are obtained by hot riveting, that is the head should be formed when hot. The second rivet head is made by hand hammers and by numatic hammers.

Types of riveting joints Riveting joints are two types such as following 1) Lap joints 2) Butt joints

Lap joints In lap joints the edge of the plate to be connected overlap each other then joint by rivet. Over lap joints can be classified as following, according to the number of rows of rivets used. 1) single riveted joints

2) double riveted joints 3) triple riveted joints

1) single riveted joints In the single riveted lap joint one row of the rivets is used. P=pitch m=marginal difference=1.5d D=dia in mm T=thickness of plate in mm The dia of rivets in various riveted joint can be founded by using above following relation ship.

2) Double riveted joints In the joint there are two rows of rivets. The rivets may be arrangement in chain arrangement or may be placed in zig zag arrangement. The distance between rows of rivets known as “row pitch”. it is calculating as follows C= 2d+6mm for chain riveting C=2d for zig zag riveting

Pitch:It is distance between the centers of one rivet to the center of the adjacent rivet in the same row. It is denoted by

p.

Marginal distance=m; It is the distance b/w the edge of the plate to the center line of the adjacent row of the rivets.

Row pitch:It is the distance b/w rows of rivets.

Diagonal pitch:It is the distance b/w the center of one rivet to the center of next rivet in the adjoining row.