Pay-off apparatus for winding machine

Abstract

A winding machine has a pay-off unit for unwinding a single- or multiple-end type wire material, a feed bobbin, and an optional take-up unit for rewinding the wire material onto one or more bobbins. The pay-off unit is associated with a wire guide device having a motorized carriage, which can slide along the axis of motion, and has an arm that rotates with respect to the carriage and is equipped with an idler wheel onto which material unwound from the feed bobbin is wound. An angular position sensor detects the inclination of the arm with respect to the carriage and a control unit governs the carriage movements as a function of the signals provided by the sensor. The optional winding unit features at least one take-up device with a gripper to grasp an end of the wire material and actuators to reduce the gripping force of the gripper during winding.

1 . A winding machine comprising: 
 a pay-off unit for unwinding single- or multiple-end wire material from a feed bobbin; and    a wire guide device for guiding the unwound material from the feed bobbin to an outlet of the pay-off unit, the wire guide device comprising: 
 a motorized carriage, which can slide along an axis of motion;  
 an arm bearing an idler wheel on which the material unwound from the feed bobbin is wound, the arm being rotatably attached to the carriage and rotating angularly along the axis of motion of the carriage;  
 sensor means to detect the slope of the material between the feed bobbin and the idler wheel; and  
 a control unit to control the movement of the carriage as a function of the signals supplied by the sensor means.  
   
   
   
       2 . A machine according to  claim 1 , wherein the sensor means comprises an angular position sensor to detect the slope of the arm with respect to the carriage.  
   
   
       3 . A machine according to  claim 2 , wherein the control unit governs the movement of the carriage along the axis of motion to keep the arm substantially perpendicular to the axis of motion while the wire material is being unwound from the bobbin.  
   
   
       4 . A machine according to  claim 3 , wherein the arm extends cantilever-like from the carriage substantially perpendicular to the axis of motion and features a connecting end hinged to the carriage and a free end bearing the idler wheel.  
   
   
       5 . A machine according to  claim 4 , wherein the sensor is a potentiometer associated with the connecting end of the arm to detect the slope of the arm with respect to the axis of motion.  
   
   
       6 . A machine according to  claim 1 , further comprising: 
 at least one take-up device for winding wire material onto a bobbin, the take-up device comprising:    at least one gripper device for gripping a strand of the material and to hold said strand while the material is wound onto the bobbin; and    at least one actuator device to reduce the gripping force of the gripper devices on said strand while the material winds onto the bobbin and holds said strand with less of a gripping force than the initial gripping force.    
   
   
       7 . A machine according to  claim 6 , wherein the actuator device acts on the gripper device to bring the gripper device from an initial operational condition, in which the gripper device holds onto said strand with a pre-determined gripping force, to a second operational condition, in which the gripper device retains said strand with a gripping force less than said pre-determined gripping force.  
   
   
       8 . A machine according to  claim 7 , wherein the take-up device comprises both a primary and a secondary actuator device that may be activated selectively to exert an initial and secondary gripping force, in that order, less than the initial gripping force, on said strand.  
   
   
       9 . A machine according to  claim 8 , wherein said secondary gripping force has a value other than zero and is substantially equal to the force exerted on said strand from the winding of the wire material onto the bobbin.  
   
   
       10 . A machine according to one of  claim 6 , wherein the gripper device comprises a moving member that cooperates when closed with a counterpart member to grip said strand between the moving member and the counterpart member, said moving member comprising a primary and a secondary element that are coupled and which slide over each other along an axis.  
   
   
       11 . A machine according to  claim 8 , wherein the primary actuator device is a pneumatic actuator device and the secondary actuator device is a spring-loaded actuator device.  
   
   
       12 . A machine according to  claim 8 , wherein the secondary element extends axially and cantilever-like from the primary element and features an abutting surface cooperating with the counterpart member and the primary actuator device acts on said primary element to firmly grip the primary element against the counterpart member with the intervention of the secondary element.  
   
   
       13 . A machine according to  claim 12 , wherein the secondary element slides with respect to the primary element for a pre-determined travel distance between a retracted position and an extracted position and is propelled by a an elastic device located between the primary and secondary elements to keep the secondary element in said extracted position.  
   
   
       14 . A machine according to  claim 10 , wherein the primary element is supported by a frame and can slide along said axis with respect to the frame and the take-up device comprises a mechanism to regulate said axial travel distance for the element with respect to the frame to provide the primary element with a pre-determined and adjustable axial travel distance.  
   
   
       15 . A machine according to one of the  claim 7 , wherein the actuator devices are controlled by a second control unit.  
   
   
       16 . A pay-off unit for single- or multiple-end wire material from a feed bobbin, comprising: 
 a feed-bobbin support device and a wire guide device to guide the unwound wire material from the feed bobbin to an outlet of the pay-off unit, the wire guide device comprising: 
 a motorized carriage that can slide along an axis of motion;  
 an arm bearing an idler wheel on which the material unwound from the feed bobbin is wound, the arm being rotatably attached to the carriage and rotating angularly along the axis of motion of the carriage;  
 sensor means to detect the slope of the material between the feed bobbin and the idler wheel; and  
 a control unit to control the movement of the carriage as a function of the signals supplied by the sensor means.  
   
   
   
       17 . A machine according to  claim 16 , wherein the sensor means comprises an angular position sensor to detect the slope of the arm with respect to the carriage.  
   
   
       18 . A machine according to  claim 17 , wherein the control unit governs the movement of the carriage along the axis of motion to keep the arm substantially perpendicular to the axis of motion while the wire material is being unwound from the bobbin.  
   
   
       19 . A machine according to  claim 18 , wherein the arm extends cantilever-like from the carriage substantially perpendicular to the axis of motion and features a connecting end hinged to the carriage and a free end bearing the idler wheel.  
   
   
       20 . A machine according to  claim 19 , wherein the sensor is a potentiometer associated with the connecting end of the arm to detect the slope of the arm with respect to the axis of motion.