Tuesday, January 27, 2009

Electronics Changes Sewing

By David Trumble

The awesome invention of the sewing machine has inspired creativity for over 150 years.

The first sewing machine was official invented when Elias Howe filed his patent in 1846. His machine required physical energy from the user to make the machine work. The user would either turn a hand crank or pump a treadle device with his or her feet. We might say it ran be human power.

Hand cranks, treadle devices, wheels, belts, and gears turned by the force of the users hand or foot. Sewing was resulted by the transfer of this movement across an upper and lower shaft to the various parts of the sewing machine. This movement caused the needle to rise and fall, while the hook and feed systems moved in concert.

A major advancement occurred when the human power was replaced by electrical power. Electric motors were mounted behind the sewing machine with a small pulley connected by a belt drove a larger wheel on the upper shaft. The electric power was essentially changed into mechanical power.

Introduction of the electrified sewing machine brought a revolution to sewing. During the early years, an electric motor was added to existing sewing machines. A hand crank or treadle sewing machine was converted by placing a drive wheel on the end of the motor shaft. The motor was lined up with the hand wheel as the sewing machine drive mechanism. Today, occasionally, a customer will come in and ask how they might re-covert an antique converted treadle sewing machine. The treadle status, has nostalgic value, but is not comparable as a sewing production machine. The electrified sewing machine has made sewing quicker, more reliable, and more convenient.

These motors convert AC (standard household Alternating Current) electricity from the home power outlet into usable kinetic energy to drive wheels, belts, gears, and levers. An AC electrical motor uses electricity to create magnetic flux between coil windings and a central core. The magnetic charges cause the center shaft of the motor to turn generating kinetic or mechanical energy. The turning shaft is connected to a gear or belt drive wheel. A belt wraps around this connection transferring the mechanical energy to the upper of the sewing machine. From this point the wheels, belts, gears, and levers transfer the energy through the sewing machine causing its parts to sew. Today many commercial sewing machines continue to use external sewing machine motors, but most home sewing machines have built in motors.

Today there are two different types of motors used in sewing machines. One is AC and the other is DC. While the flow of electricity must always operate in a continuous loop or circuit, that loop is constantly flipping back and forth with Alternating Current. That loop continues to flow in only one continuous direction positive to negative with Direct Current. Transformers are used to convert one to the other. Electric motors come in two types AC and DC. In both cases the electricity used to run the motor must operate in a continuous unbroken circuit or loop. If the flow of electricity in the circuit flows in one direction and then in the opposite direction, it is called alternating current. If the flow is in only one direction within the loop, it is DC or direct current. Use of a transformer can convert AC to DC or the reverse.

AC motors are used in conjunction with levers, gears, cams, and other mechanical devices to make stitches and run the sewing machine in what are known as mechanical sewing machines. For over a hundred years, this applied to all sewing machines. Even now AC driven mechanical sewing machines are used for commercial use and low end models.

In recent years, another revolution has begun. The introduction of integrated computer circuits and other electronics have brought huge improvements in the reliability and smoothness of operations. Another advancement has been the introduction of DC pulse motors to control the sewing machine and produce stitches. The result has been amazing. These modern sewing machines make sewing so much easier and enjoyable.

The power system of your sewing machine really does matter. It matters if you are looking to buy a new machine. It matters when you understand what you are using. It matters if your are repairing sewing machines. - 16003

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