CONSTRUCTION OF A IRON BOX

                                                     construction of a iron box
                              
1. Bakelite handle

                handle of a iron box used for holding it.The handle can be made either with wood or with plastic. The handle is attached to the cover plate with the aid of screws. Studs can also be used for this purpose

2.Pilot Lamp

The pilot lamp is housed in the cover plate of the electric iron. One end of the pilot lamp is connected to supply, while the other end is connected to the heating element. A shunt resistance is provided across the pilot lamp which assists in providing a voltage drop. The shunt is designed to provide a voltage drop of 2-5 volts
LAMP GLOWING  it indicates  temperature is within predetermined value current is flowing
lamp is not glowing  temperature is more than predetermined value  current is not flowing
                                                  
3.steel cover     
 steel cover of the iron box

4.Sole Plate

The sole plate is the thick, triangular-shaped slab of iron that forms the base over which the electric iron is built up. The bottom surface and edges are heavily chromium plated, to prevent it from rusting. The base plate should hold the iron pressure plate and cover plate in position. For this purpose we can see two or sometimes three studs in the base plate. These studs aid in holding the position of cover plate and pressure plate.

5.Pressure Plate

This plate is generally called the top plate as it follows the shape of sole plate. The pressure plate has some holes through which the studs form the base plate passes through. We should tighten the nuts on the studs in such a way that the pressure plate and sole plate are pressed tight against each other. In some iron the pressure plate is heavy and made of cast iron while in some other cases, it is a thin sheet of steel, about ¼ cm thick
                                                            

6.The Heating Element

The heating element is present between the sole plate and pressure plate. It is pressed hard between the two plates. The heating element consists of nichrome wire wound around a sheet of mica. The two ends of the nichrome wire are connected to the contact strips. The contact strips are connected to the terminals of the iron. There are two reasons for which mica is chosen in the heating material. Mica is a very good insulating material. Besides that mica can also withstand very high temperatures. The entire assembly of mica sheet, nichrome wire and contact strips are riveted together resulting in a mechanically sound and robust construction. There is an asbestos sheet, which separates and thermally insulates the top plate from the heating element.

                                                                

7.The Cover Plate

The cover plate is made of thin sheet of iron. It is placed on top of the base plate and it covers all the internal parts of the iron. The handle and connector are only attached to the cover plate.