orking Principle of Cylinder Bed Heavy-Duty Lockstitch Sewing Machine
This machine forms lockstitch with upper thread and bobbin thread. The needle pierces thick material and forms a thread loop underneath. The large rotary hook catches the loop and interlocks the bobbin thread with needle thread, while the take-up lever tightens the stitch.
Its most important feature is triple compound unison feed: the needle, walking presser foot (upper feed) and bottom feed dog advance the fabric synchronously. All layers move together at the same pace, preventing layer shifting, slipping or uneven stitch length on multi-layer leather, canvas and webbing.
Different from flat-bed machines, it adopts a slim cylinder arm. Tubular, curved and pre-formed workpieces such as bag gussets, shoe uppers and saddlery can be sleeved onto the cylinder for continuous all-round sewing without flattening the finished part.
Driven by heavy-duty servo motor and reinforced transmission system, the large-capacity rotary hook supports heavy bonded thread. Optional auto thread trimmer, pneumatic foot lift and backtack improve efficiency for heavy-duty production.