Different parts of lock stitch/plain sewing machine

Study of different parts of lock stitch sewing machine

Maruf Mahfuz

maruf.txt@gmail.com

Department of textile engineering 

World University of Banhladesh

Website: http://about.me/maruf.mahfuz.90

01738676060

Objective:

• To obtain a clear knowledge on particular actions of different parts of lock stitch sewing machine.
• To clearly observe the mechanism, constructions and actions of different parts of lock stitch sewing machine.

Figure and Function

Bobbin:

Bobbin holds the thread inside the machine. Bobbin is a small yarn package. It is used for storing specific amount of sewing thread on it (Lower thread). Bobbin is a spool underneath the bed that provides the lower thread.

Figure: Bobbin

Bobbin case:

Figure: Bobbin case

To hold the bobbin in the particular place of the machine.
To control lower thread tension.
This moves into position to catch the top thread and form the stitch as the needle is lowered into the bobbin chamber.

Thread Tensioner:

Figure: Thread tensioner

To maintain the uniform tension of sewing thread (Top thread) during sewing.

To control the tension (i.e. increase & reduce the tension) of the swing thread during sewing.

Thread guide:

It holds the thread in position from the spool to the needle.

Figure: Thread guide

 Stitch density controller:

Figure: SPI controller

It is used for increasing and decreasing the stitch density per inch during sewing.

Back stitch lever:

It revers the stitch direction& make back stitches to keep the seam in place.

  

Figure: Back stitch Lever

Throat plate:

Figure: Throat plate

Throat plate is used for smooth movement of fabric. A plate under the presser foot with an opening through which the needle moves up and down during stitching. This plate has seam guides engraved into it.

Feed dog:

Figure: feed dog

It is a toothed part that moves the fabric advance to sewing area. Mechanism which feeds the fabric under the presser foot as you guide it. The feed dog also regulates stitch length according to how much fabric is passing under the presser foot as the machine stitches.

Presser foot:

The pressure foot is the ski-shaped part that passes the fabric down. When lowered this mechanism presses down on the material to steady its movement as it is fed under the needle.

Figure: presser foot

Hand wheel:

A wheel located on the right side of the machine which is driven by the motor; although it can be turned manually.To raise & lower the needle and to take- up the lower thread from bobbin.

Figure: hand wheel

Needle:

To make a hole on the fabric surface for passing the yarn from one side to another.

For completing sewing action.

Figure: Needle parts

Thread take- up lever:

To take up the top thread from the cone.

It’s up and down motion feeds the thread to the needle and tightens the loop formed by the shuttle.

Figure: Take up lever

Automatic bobbin winder:

To wind the sewing thread automatically into the bobbin.

Figure: Automatic bobbin winder

Conclusion:

Sewing Machine, machine designed to join pieces of fabric or leather by means of either a lockstitch or a chain stitch. The lockstitch, which is used in most modern machines, is formed from two threads and the chain stitch from a single thread. By this experiment we able to know about the parts of a lock stitch sewing machine and their functions clearly.