Abstract: An improved air cooling device for the production of cast film is shown. The device is intended to increase production rates for film without reducing the level of film gauge control. The devices utilizes a soft box for the bulk of the cooling and a directional source of pressurized air to deflect exhaust air from the soft box from striking the web curtain between the die and chill roll.

Abstract: A sideweld bag making machine utilizing a rotary transfer device and wicket conveyer is equipped with screw adjustable transfer wicket pins. The bases for the transfer wicket pins are mounted on a threaded rod having two sections of thread, each of opposite hand. Rotation of this threaded rod affects the separation of the wicket pins. Adjustment of vertical position is accomplished by means of two jacking screws or a screw adjustment in conjunction with a motion limiting rail element.

Abstract: A thermoplastic bag making machine having a sealing bar assembly driven by two separate linear drive units is initialized following full shutdown by traversing the linear drive units at constant velocity against mechanical stops, and then resetting position error signals and traversing the bar a known distance to a home position. This procedure is also useful for single linear drive units, as well as multiple linear drive units that must be coordinated for position and motion. In the case of multiple drive units, procedure for offsetting travel distances off the stop for non-uniformity in stop positions is utilized.

Abstract: Apparatus and method are described for controlling thickness of plastic films produced by the blown film process. The apparatus is an air cooling ring modified to include devices for locally modifying the temperature of the air discharged from the air ring onto the blown bubble. Local variations in the temperature of the cooling air applied to the surface of the bubble result in variations in the bubble cooling rate and viscosity, with consequent variations in thinning during transverse bubble expansion. The method includes controlling the location and extent of local temperature variation applied to the bubble in response to comparison of measured film thickness with a desired film thickness.

Abstract: A heat sealing bar assembly is disclosed that is intended to avoid distortion of the heat sealing edge due to thermal expansion of the heated sealing bar with respect to the unheated support beam to which it is mounted. The mounting means include a fixed center support, end supports that permit axial sliding of the ends of the heated seal bar with respect to the support beam, and a series of jacking screws between the center support and the end support for adjusting the shape of the heated sealing bar.