Expander and guider roller

An expander and guider apparatus for expanding and guiding a sheet-like travelling article comprising:

• an expander roller which engages the article comprising (a) a straight shaft, (b) rotary disk groups each having a plurality of rotary disks rotatably put on said shaft, and (c) a stretchable and resilient cylindrical member closely fitted on said rotary disk groups, said rotary disk groups being formed by a left-hand rotary disk group and a right-hand rotary disk group of which respective rotary disks are inclined in the opposite directions from the longitudinal center of said shaft to the both ends thereof, the inclination angles of said rotary disks in each of said rotary disk groups being gradually increased by a predetermined amount in the direction from the center to each end of said shaft, said expander roller being characterized in that the left-hand rotary disk group is displaced in the circumferential direction of the shaft by about 90.degree. with respect to the right-hand rotary disk group such that the relative expanding action of each said rotary disk groups on the article is non-symmetrical with respect to the other said rotary disk group except where the article contacts the expander roller at a unique neutral position where the relative expanding action of each said rotary disk group on the article is symmetrical;
• a selvedge detector located downstream of said expander roller for detecting the position of a travelling edge of the article and for producing a signal indicative of the deviation of the edge of the article on either side of a predetermined desired position;
• and
• a shaft rotating means for selectively displacing said shaft in the circumferential direction in response to signals from said selvedge detector of a deviation of the edge of the article from the desired position such that when the travelling article upsteam of said expanding roller is laterally shifted as sensed by said selvedge detector, the expanding action of said expander roller is adjusted whereby the travelling article is preferentially expanded on the opposite side from the direction of shift to compensate for the shift and to thereby produce an expanded article downstream of said expander roller which is not shifted.