General Lockstitch Sewing Machines
General lockstitch sewing machines are essential in the sewing industry, forming a basic lockstitch (stitch type 301) by interlocking needle and bobbin threads. They are valued for stable stitching, high efficiency, and wide material adaptability.
1. Stitch Formation Principle
The machine forms stitches through synchronized steps: needle penetration, thread loop capture by a rotating hook, interlocking with bobbin thread, and stitch tightening by the thread take-up lever, ensuring neat, strong, and unravel-resistant seams.
2. Core Parameters & Structure
Bed Type: Standard flat-bed with 250–305mm throat space; long-arm versions for bulky items.
Performance: Max speed 4,000–5,000 sti/min; adjustable stitch length (0.1–5mm); presser foot lift 5–13mm (up to 30mm for heavy-duty models).
Feeding System: Bottom feed (standard), needle feed (anti-slippage), and compound feed (for challenging materials).
Hook & Bobbin: Vertical-axis large rotary hook with large bobbin capacity for less downtime.
3. Key Functions
Adjustable thread tension (balanced stitches); reverse stitching (seam reinforcement); fully enclosed automatic lubrication (wear reduction, clean sewing); computerized models offer automatic thread trimming, presser foot lifting, and programmable stitches.
4. Classification & Application
Classified by speed (low/medium/high), needles (single/double), and duty (light-medium/medium-heavy/heavy-duty), suitable for garments, home textiles, leather goods, etc.
Conclusion
With mature, reliable technology and versatility, lockstitch machines (mechanical or computerized) remain indispensable in sewing and apparel manufacturing.