Sewing machine with needle position control means

Claim 1

IN A SEWING MACHINE, PARTICULARLY AN INDUSTRIAL SEWING MCHINE, A MAIN SPINDLE FOR THE SEWING MACHINE, A DRIVING MOTOR HAVING A SHAFT, AUTOMATAIC BRAKE MEANS FOR THE MOTOR, PULLEYS FORO SAID SPINDLE AND SHAFT, A BELT TRAINED OVER SAID PULLEYS FOR DRIVING SAID SPINDLE, COUPLING MEANS BETWEEN THE SPINDLE PULLEY AND THE SPINDLE ADAPTED TO COUPLE THE SPINDLE PULLEY TO THE SPINDLE, SAID COUPLING MEANS INCLUDING AN ELECTROMAGNETIC PART AND A CLAW PART WITH SAID CLAW PART BEING CONNECTED TO THE SPINDLE TO PROVIDE TANGENTIAL PLAY BETWEEN SAID MANGETIC PART AND SAID CLAW PART, A SWITCH ON SAID ELECTRO-MAGNETIC PART CONTROLLED BY THE RELATIVE MOVEMENTS OF THE ELECTRO-MAGNECTIC PART WITH RESPECT TO THE CLAW PART, A CENTRIFUGAL SWITCH ON SAID ELECTRO-MAGNETIC PART, AND EXCITING COIL IN THE ELECTRO-MAGNETIC PART, A CIRCUIT IN WHICH SAID COIL AND SAID SWITCHES ARE LOCATED, COLLECTOR RINGS ON SAID ELECTROMAGNETIC PART THROUGH WHICH SAID CIRCUIT IS FED, A CLOSED CONTACT RING ON SAID ELECTRO-MAGNETIC PART, AND A CONTACT STRIP EXTENDING ABOUT AT LEAST A PART OF THE PERIPHERY OF SAID ELECTRO-MAGNETIC PART WITH SAID CONTACT RING AND STRIP COMPLETING A CIRCUIT TO SAID COIL TO ESTABLISH THE COUPLING OF THE PULLEY ON THE SPINDLE WITH THE SPINDLE.