Abstract: An apparatus for coating a pattern of spaced discrete patches on a web of material includes an extrusion die and a metering pump which supplies coating fluid to the extrusion die from a fluid reservoir. A valve directs fluid to either the extrusion die or the fluid reservoir and a piston provides a controlled excess of flow of fluid to the extrusion die. A controller, including a digital preset counter, controls the length of the coated portions of the web, the distance between the coated portions of the web, and the timing of the valve with respect to the operation of the piston.

Abstract: An apparatus for measuring the dynamic contact angle of a coating on a discrete web segment includes a rotatable coating wheel around which the web segment is mounted and a syringe which produces a coating bead having no edge bead. The interface between the coating and the web is viewed in a plane parallel to the axis and the surface of the coating wheel and the contact angle is measured.

Abstract: Automatic tracking of an endless belt, such as a coated abrasive belt, is provided by fitting the belt with at least one permanent magnet, preferably of a flexible, rubber bonded sheet-like variety such as is conveniently adhered to the backside of the belt. One or more magnetic sensors positioned transversely to a longitudinal line defined by the path of the magnets as the belt is driven between rollers detect the magnets in the event the belt exceeds an allowed extent of transverse movement, in which event a control signal is generated which activates a steering mechanism causing the belt to move in the opposite transverse direction.