Patent ID: 8104413
Filing Date: 2012-01-31
Classification: D05B

Abstract:
1. A camless automated thread cutting system for an electronic lockstitch pattern tacking sewing machine having a sewing needle driven by a main shaft and having a knife mechanism in proximity with said needle for cutting thread at the end of a pattern sewing cycle, said system comprising: a pneumatic actuator for mechanically engaging and actuating the knife mechanism; an electrically actuated valve in fluid communication with said pneumatic actuator; an electronic controller having first and second inputs, said first input for receiving a signal from the machine indicative of the end of a sewing cycle, and a control signal output to said valve for actuation thereof; a plurality of discs adapted for mounting on the main shaft for rotation therewith whereby said discs rotate in sync with upward and downward needle movement during the sewing cycle, said discs being independently adjustable in angular orientation; and a proximity sensor operatively coupled to said plurality of discs for detection of first and second points thereof during rotation thereof, said sensor supplying a corresponding signal to said second input of said electronic controller; wherein said electronic controller is responsive to the machine signal and to said proximity sensor signal for generating said control signal for actuation of said valve so as to initiate and subsequently terminate a knife movement sequence at the end of the sewing cycle.