Method for winding strips on a tire building machine

Abstract

A strip member is wound by a tire building machine having a building drum for taking up a strip member of predetermined length without discrete ends and a transfer conveyor for feeding the strip member to the building drum. The winding-start end of the strip member transferred from the transfer conveyor to the building drum and the winding-finish end of the strip member are detected by means of end sensors, measuring the angle through which the building drum has rotated from the output of a winding start signal to the output of a winding finish signal in response to output signals from the sensors by means of an angle detector. A lapping margin between the winding start end and the winding finish end of the strip member is calculated based on the rotational angle and diameter of the building drum by means of an operational means.

1 . A method of winding a strip member on a drum of a tire building machine in a winding operation building a tire, comprising: 
 providing a first strip end sensor arranged to sense a first position along a path of rotational advance of a surface of said drum which is angularly displaced along said path of rotational advance from an angular position along said path of rotational advance whereat said strip member is brought into initial contact with said drum in order to detect a first detection position on said surface of said drum whereat said strip member is brought into initial contact with said drum;    providing a second strip end sensor arranged to sense a second position along said path of rotational advance of said surface of said drum which is angularly displaced from said first position along said path of rotational advance at which said first strip end sensor is directed;    providing an angle detector to detect an angle of rotation of said drum;    rotating said drum in a drum rotational direction a front end of said strip member applied to said drum to begin wrapping said strip member on said drum;    detecting said front end of said strip member at said first detection position using said first strip end sensor and initiating a first angular measurement using said angle detector;    detecting arrival of said front end of said strip member at said second strip end sensor;    completing said first angular measurement using said angle detector;    initiating a second angular measurement based on said front end of said strip member being detected by said second strip end sensor and continuing to rotate said drum in said drum rotational direction;    calculating a first angle representing angular displacement from said second strip end sensor to said first strip end sensor in the drum rotational direction based on output from said angle detector;    detecting arrival of a trailing end of said strip member at said first strip end sensor brought about by rotating said drum in said drum rotational direction;    completing said second angular measurement using said angle detector based on said trailing end of said strip member being detected by said first strip end sensor to yield a second angle; and    calculating an overlap length if said second angle is greater than said first angle and calculating a gap length if said second angle is less than said first angle.    
     
     
         2 . The method of  claim 1  wherein: 
 said overlap length is calculated using the formula       X =( D+ 2 t )π×((θ 1 −θ 0 )/360)   when said second angle is greater than said first angle, where: 
 X=said overlap length;  
 D=a diameter of said drum;  
 t=a thickness of said strip member;  
 θ 0 =said first angle; and  
   θ 1 =said second angle; and    said gap length is calculated using the formula       Y =( D+ 2 t )π×((θ 0 −θ 2 )/360)   when said first angle is greater than said second angle and where θ 2  equals said second angle and Y equals said gap length.    
     
     
         3 . The method of  claim 2  further comprising: 
 determining whether one of said overlap length and said gap length is outside an allowable range; and    stopping the winding operation of the tire in response to said one of said overlap length and said gap length being determined to be outside said allowable range.    
     
     
         4 . The method of  claim 2  further comprising: 
 determining whether one of said overlap length and said gap length is outside an allowable range; and    providing an indication of gap length being out of said allowable range in response to said one of said overlap length and said gap length being determined to be outside said allowable range.    
     
     
         5 . The method of  claim 1  further comprising: 
 determining whether one of said overlap length and said gap length is outside an allowable range; and    stopping the winding operation of the tire in response to said one of said overlap length and said gap length being determined to be outside said allowable range.    
     
     
         6 . The method of  claim 1  further comprising: 
 determining whether one of said overlap length and said gap length is outside an allowable range; and    providing an indication of gap length being out of said allowable range in response to said one of said overlap length and said gap length being determined to be outside said allowable range.