Seam responsive rolls and method

In a web handling apparatus for web material such as textile fabric and having means for guiding and advancing lengths of web material joined by widthwise seams along a path of travel, and a pair of cooperating nip rolls between which the web material is advanced at a predetermined position along its path of travel;

• an improvement which controls the relation between the nip rolls for jumping seams in the web material and comprising:
• a plurality of seam detector means mounted adjacent said path of travel upstream of said pair of nip rolls, each of said seam detector means being adapted to sense widthwise seams in the web material advancing along said path of travel toward said nip rolls, and control means operatively connected to said detector means and to at least one of said nip rolls for separating the same from the other nip roll and from the web material in response to and in predetermined relation with seam sensing by all of said detector means.

In a web handling apparatus having means for guiding lengths of web material joined by widthwise seams along a path of travel, and a pair of cooperating nip rolls between which the web material is advanced at a predetermined position along its path of travel;

• an improvement comprising:
• a plurality of detector means mounted adjacent said path of travel, each for signalling electrically the passage thereby of widthwise seams in web material guided along said path of travel toward said nip rolls, coincidence circuit means electrically connected to said detector means for distinguishing between signalling by all of said detector means within a predetermined interval of time and indicative of the passage of a widthwise seam and signalling by less than all of said detector means and indicative of a false signal from at least one detector means, and control relay means electrically connected to said coincidence circuit means and operatively connected to at least one of said nip rolls for separating said nip rolls in response to signalling by all of said detector means.

In a method of handling lengths of web material joined by widthwise seams which includes guiding the material along a path of travel and engaging the material with a pair of nip rolls, an improvement comprising sensing at a plurality of points along the path of travel the passage of a widthwise seam, and responding to and in predetermined relation with the sensing of a seam at all of the points by separating the nip rolls.

In a method of handling lengths of web material joined by widthwise seams which includes guiding the material along a path of travel and through a nip formed by a pair of rolls, an improvement comprising sensing the passage of a widthwise seam at a point along the path of travel spaced at a predetermined distance from the nip, responding to the sensed passage of a seam by measuring the length of material moving along the path, and moving at least one roll relative to the material in response to the measured length of material equaling the predetermined distance so as to separate the rolls and open the nip in the area of the seam.