Abstract: A liquid valve particularly suited for dispensing of glue at high repetition rate has a solenoid-retracted pin that normally engages a valve seat to close the valve. Glue under pressure enters the chamber in which the pin operates, close to the valve seat. To seal against the flow of pressurized glue up along the pin toward the solenoid, and also to exert a light valve closing force on the pin, a thin metal bellows member is sealed and fixed to the pin near its lower end, at one end of the bellows, and to a connector within which the pin slides, at an opposite, upper end of the bellows. The geometry of the valve seat and the valve closure end of the pin is such that only a very slight retraction of the valve pin opens the valve sufficiently to deliver glue at full velocity through the valve orifice. The valve is capable of accurate glue dispensing through a wide range of operating pressure.

Abstract: A glue head delivers lines or spots of glue onto a substrate, such as packaging materials, with precision positioning of the glue pattern, with short and balanced on/off compensation times essentially independent of glue pressure, and at high nozzle velocity. Pressurized glue advances into a plenum of the glue head preferably in a horizontal direction, then into a short and low-volume exit tube and through a nozzle, flowing in a direction perpendicular to the inflow direction. Flow to the nozzle is closed by a diaphragm valve comprising flexible elastomeric material which seats against the upstream end of the exit tube. An important feature is that glue actuator pressure is balanced, and smooth operation and glue delivery are achieved, by a rocker arm above the glue valve which, when the valve is closed by pushing the elastomeric material against the glue delivery tube, releases pressure on the glue at an upstream point in the glue plenum.

Abstract: A method for counting conveyed workpieces, such as on a variable speed conveyor belt, includes sensing interruptions via an object sensor such as an optical sensor with a light beam, and with a computer, applying a mathematical comparison between duration of interruptions to the light beam path and gaps that separate these interruptions. The comparison determines which interruptions are caused by the passage of conveyed workpieces and which interruptions are caused by the passage of other objects such as components of the conveyor belt. The method described involves the selection of a preset factor used in a ratio comparison between the duration of interruptions to the light beam and the gaps that separate these interruptions such that the computer is able to accurately count objects such as sheets of paper pulled by gripper bars and distinguishing between sheets of paper and gripper bars such that gripper bars and clips are not incorrectly counted as sheets of paper.

Abstract: A system for accurately controlling the start and stop positions for operations on conveyor-moved products, such as for applying glue lines, perforations or slits on sheets of paper, uses product position rather than timing to accurately control "on" and "off" operation positions on the product. The entry of a sheet of paper, for example, onto the conveyor path is noted by detecting the leading edge of the paper moving past an optical sensor. The location of the sheet is always known in a computer, due to conveyor position information continually fed to the computer. Distances which will be involved in the compensation times for the operating devices (e.g.