Wikijunior:How Things Work/Sewing Machines

An Elna sewing machine

Who invented it?

Elias Howe.

Elias Howe Sewing Machine, 1846.

Elias Howe (left) and Englishman Thomas Saint in 1790, invented the sewing machine for the First Industrial Revolution to reduce hard, manual sewing work.

Specifically Elias Howe invented the lock stitch mechanical stitch design (left) used in most home sewing machines today. An early model of his sewing machine was included in his patent.

How does it get power?

Modern sewing machines usually get power from a power socket, but some run on big batteries, for example the size D or C. Although the first invented sewing machine was run by hand, by rotating the sewing machine's wheel.

How does it work?

Chain stitch

Thomas Saint's chain stitch. An awl preceded the eye pointed needle to make a hole in preparation for the thread.

The sewing machine sews by pulling a thread of string through the fabric using its needle, right at that time the thread gets grabbed by the looper underneath the fabric before it pulls up. Once the needle is up again, the feed dog mechanism pulls the fabric forward or backward. (depending which way your machine is running) Once the needle pushes through the fabric again, the new piece of string passes directly through the loop it has just made before. The looper again grabs the string. This is done over and over until you stop the machine.

Feed dog mechanism

The feed dog mechanism on a sewing machine.

The feed dog mechanism moves the fabric by moving forwards, going down, going backwards and going up again, this is done fast and repeatedly.

Lock stitch

A lockstitch diagram.

Formation of a lock-stitch using a boat shuttle as employed in early domestic machines.

Same as the chain stitch, the needle lowers, pulls a loop of thread of string through the fabric, needle rises as the fabric gets pulled along by the feed dog mechanism but instead of joining the two loops together, it joins them to the bobbin's thread of string.

Bobbin

The bobbin is a spool of thread positioned underneath the fabric as the 2nd source of string. It is positioned in the shuttle.

Shuttle hook

The shuttle hook is a sharp hook positioned near the shuttle. It grabs and pulls the thread of string the needle lowers while rotating itself. Once it has rotated 360° the bobbin's string catches the needle's string. This gets repeated over and over.

Shuttle

The shuttle is simply a place for the bobbin to sit in. There is a motor inside it which spins the bobbin.

How dangerous is it?

The modern sewing machine can be dangerous, for example if the needle pokes someone's hand or the motor starts smoking because of the hard fabric. Some old sewing machines had a bulb that you could accidentally burn your hand with when you move it but those were discontinued and LED lights were used instead.

How does it vary?

There are lots of sewing machines: there were ones ran by hand or electricity and different brands of them.

How has it changed the world?

They have changed the world by making people sew easier by sewing for them.

What idea(s) and/or inventions had to be developed before it could be created?

The wheel must have been made or the manual sewing machine couldn't operate. Plastic, metal and electricity must have been made for modern sewing machines.