We all use sewing machines at our home. Some of us even use them for a living. Whether directly or indirectly, we all avail the services of sewing machine in some way or the other. But not all of us is familiar with the way in which the sewing machine functions. Here we will try & understand the mechanisms that are intrinsic to the way a sewing machine functions.
How Does Stitching Work?
Stitching in a sewing machine is done through the loop stitch mechanism. This mechanism is much different from the simple hand stitch method. In the hand stitch the thread is tied to a small eye at the end of the needle away from the needle point. The needle & the thread passes through the two pieces of fabric & comes back in the reverse direction. This way it attaches the fabrics together. But this method can’t be achieved through a machine.
In the loop stitch mechanism the eye of the needle is right behind the needle point rather than at the end of it. Infact in a sewing machine the needle is a highly sophisticated piece of technology. In the sewing machines the needle pass only partly through the fabric (meaning it doesn’t completely go through the fabric & comes out from the other side as happens in the hand stitch mechanism). The needle is moved up & down by the needle bar. When the needle pierces through the fabric, it creates a small loop of thread from one side to the other. A mechanism underneath the fabric grabs this loop and wraps it around either another piece of thread or another loop in the same piece of thread. That’s how sewing happens in a loop stitch method. There are several types of loop stitches that can be done e.g. chain stitch, lock stitch etc.
Various components of a sewing machine:
A mechanical sewing machine is run by raw human power. It works through many gears & cams. But in an electrical sewing machine the energy for running the machine comes from the motor which is embedded in the machine & runs with the help of electricity. The exact configuration of these components in a machine varies from one brand to the other. But the idea & technology behind them is somewhat same.
In general the electric motor is connected to the drive wheel by a drive belt. The drive wheel rotates along the upper drive shaft. The upper drive shaft is connected with several different machanical elements of the machine. End of the shaft rotates a crank which pulls the needle up & down.
The thread runs from the top spool through a tension disc assembly. The lower drive shaft also moves linkages that moves feed dog mechanism. One linkage moves the feed dog forward & backward and the other moves it up & down. So it enables the feed dog to move both horizontally & vertically at the same time. The motor is controlled by a foot pedal. This foot pedal allows the sewer to control the speed of the motor, thereby controlling the speed of sewing.