A table fan is an electrical appliance that modulates the circulation of air at a place. The main purpose of a table fan is to cool down the temperature of the surroundings and provide proper ventilation. Most of the table fans consist of a mechanism that helps the top of the fan to move in a horizontal direction along with the rotatory movement of fan blades in a circular direction to circulate air. The speed with which the blades of the table fan move can be adjusted as per requirement. The angle of elevation of the fan or the pitch of the table fan is also generally adjustable.
Working of a Table Fan
A table fan consists of a power button and a few buttons to control the speed of rotation of the fan blades. When the fan’s main power supply button is turned on, the motor gets supplied with electric current. The main purpose of the electric motor is to convert electric energy into mechanical energy. The shaft of the motor is connected to the fan blade. This means that the rotatory motion of the motor shaft gets transferred to the fan blades, thereby causing them to rotate along the axis. To move the body of the fan sideways, the designated switch is pressed. The horizontal motion of the fan is typically controlled by a four-bar mechanism present in the internal circuitry of the fan. A four-bar mechanism consists of a fixed bar attached to three movable bars. Here, the spinning motion of the fan is required to be converted into a side-to-side motion. The bars of the four-bar mechanism are connected edge to edge with the help of pins. The three bars other than the fixed bar are the free bars and are typically known as crank, coupler, and follower. The motor causes the crank bar to rotate around. The coupler and the follower bars tend to follow the motion. The length of the bars plays a very important role in deciding the type of motion exhibited by the four-bar mechanism. The internal mechanism of the table fan consists of a component known as the worm that spins about its axis. The worm is further connected to a worm gear. Another gear is present in the internal structure of the fan and is connected to the crank. These gears are connected to each other with the help of a pin. A spring combined with two ball bearings is connected to the top of the pin. When the table fan is supplied with power, the spinning motion of the worm gets linked to the worm gear, which causes it to rotate. The pin attached to the gear also starts spinning. Finally, the motion from the pin gets transferred to the final gear, which helps the crank to move and the four-bar mechanism to oscillate the table fan linearly. The angle of the fan can be adjusted with the help of the pin that connects the gears and the four-bar mechanism. When the pin is lifted, the fan points downwards and cannot exhibit linear motion. Similarly, when the pin is pressed the fan points upwards and is capable of moving sideways.