1. COMPARISON OF THE CAPABILITIES OF SEWING MACHINES THAT WORK ON THE BASIS OF:
No. Technologies for forming a lockstitch type 301. Technologies for forming a double thread
chain stitch type 401 using a looper
carrying the bottom thread.
New ZARIF technology for forming a new double
thread chain stitch type 401 from 2021
using a rotary looper.
TYPE 301 TYPE 401 NEW
TYPE 401
1. Sews materials up to 8 mm thick with a needle bar stroke length of 32 mm.
NO
(necessary to increase the stroke of the needle
bar more than 32 mm)
NO
necessary to increase the stroke of the needle bar
more than 32 mm)
YES
2. Qualitatively stitches different types of materials having different thicknesses, stiffness and density without adjusting the normal tension of the threads.
NO NO YES
3. Guarantees sewing without skipping a stitch, without breaking threads, without breaking the needle and without deforming the needle tip.
NO NO YES
4. Can get a tight join of materials using a stitch.
YES NO YES
5. When sewing elastic materials, can achieve a more elastic seam.
NO YES YES
6. Can continue sewing without adjusting the looper or hook relative to the needle after installing a different needle number.
NO
(maximum allowable gap between the hook point
and the needle is 0.1 mm)
NO
(maximum allowable gap between the looper point
and the needle is 0.1 mm)
YES
(maximum allowable gap between the looper
point and the needle is 0.5 mm)
7. Can securely tacking the end of the seam in any place of the sewn material.
YES NO
(stitch length can be reduced to 1 mm, which does
not allow to securely tacking the end of the seam by
condensation stitches with a stitch length of 1 mm)
YES
(condensation stitches with a stitch length
of 0.5 mm)
8. Sewing machine have a very simple mechanical design.
NO NO YES
9. Needle guards are used in sewing machine to increase the reliability of stitch formation.
YES YES NO

2. TYPE 301 TYPE 401 NEW
TYPE 401
10. The sewing machine can sew for a very long time without filling the threads.
NO
(frequent refilling of the hook bobbin with the
bottom thread)
YES
(top and bottom threads are fed from large coils)
YES
(top and bottom threads are fed from large coils)
11. There is a part in the sewing machine that may jam and stop suddenly.
YES
(this is a hook, if the thread segments get into the
hook slip zone, the hook may jam)
NO NO
12. It is possible to increase and decrease the tightening forces of the top thread loop in the stitch without changing the normal tension of the top thread.
NO NO YES
(with the help of know-how)
13. The thread take-up of the top thread smoothly (evenly) reduces and tightens the loop of the top thread when forming a stitch.
NO
(non-smooth reduction and tightening of the top
thread loop)
NO
(complex system of reducing and tightening the loop
of the top thread with the participation of a needle)
YES
14. The sewing machine uses an ordinary needle with one long groove.
YES NO
(special needle with two long grooves is used
because of the needle participation in the
preliminary tightening of the loop of the top thread
located in the previous stitch)
YES
15. All parts of the sewing machine have a high service life.
NO
(service life of the hook is limited due to the
presence of a slip zone in the hook)
YES YES
16. The sewing machine can sew for a very long time without cleaning the dirt under the needle plate.
NO
(hook must be cleaned of dirt frequently)
YES YES