Edge alignment apparatus

An apparatus for checking and correcting the alignment of a continuous web or fabric material adapted to be supported in and moved through said apparatus, comprising a frame, a smooth shaft attached to said frame, a laterally-movable carriage slidably attached to said shaft and adapted to support said web, photoelectric sensing means mounted on said frame comprising a photoelectric light source and a photocell spaced therefrom and adapted to receive a continuous light beam from said light source and to sense variations in the level of illumination received from said light source during operation of said apparatus, said sensing means being so positioned that one edge of a continuous moving web passing therethrough is adapted to block a predetermined partial portion of the light beam between said light source and said photocell when said moving web is in centered position, means for moving said web through said sensing means so that one edge thereof normally blocks a predetermined partial portion of said light beam, a bi-directional solenoid associated with said frame and with said laterally-movable carriage and adapted to slide said carriage laterally on said smooth shaft in either direction relative to said frame, and means associated with said sensing means and with said solenoid for activating said solenoid to slide said carriage in a direction away from said sensing means when the edge of the web blocks more than said predetermined partial portion of said light beam and to slide said carriage in a direction towards said sensing means when the edge of the web blocks less than said predetermined partial portion of said light beam.