Patent ID: 9127387
Filing Date: 2015-09-08
Classification: D05B

Abstract:
1. Improved needle bar driving system for sewing machines, comprising an armshaft rotating with a predetermined speed; a needle bar driving assembly driven by said rotating armshaft; a needle bar coupled to and driven by said needle bar driving assembly to perform a forced reciprocating guided linear movement along a substantially vertical first axis; a counterweight driving assembly driven by said rotating armshaft; and a counterweight piston driven by said counterweight driving assembly, said counterweight piston performing also a forced reciprocating linear guided movement along a second axis equal with or being parallel to said first axis, wherein the movements of said counterweight piston is always opposite to the movement of said needle bar, wherein the combined torque of said counterweight piston and said counterweight driving assembly acting on said armshaft is substantially equal to the combined torque of said needle bar and needle bar driving assembly acting also on said armshaft, but said two torques having opposite directions, whereby said armshaft gets substantially balanced.