US 4,819,928 AGranted

Plastic film air table conveyor

AssigneeMobil Oil Corporation

InventorsPaul V. Osborn, Clyde C. Tendick

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Abstract

A plastic film handling apparatus includes an air table formed by a box having a surface crossed by a conveyor, in the form of endless belts surrounding the box, in which a multiplicity of individual air chambers is provided. Each of the individual chambers is selectively pressurized (negative or positive) by selective coupling of the chambers with a blower through a manifold chamber. Openings through the surface couple each chamber with an overlying plastic film. A second blower and manifold chamber, selectively coupled with the individual chambers, is provided so that at least two air pressure levels, different from atmospheric and one another, can be generated. The air manifold chambers are isolated from one another adjoining each of the individual air chambers and are selectively coupled with individual chambers by the removable gates therebetween or by the setting of other conventional settable air couplings between the individual chambers and each manifold chamber. A static bar is provided to apply a static electric charge to the plastic film to attract the film to the conveyor and hold the film in place in the absence of suction.

Claims13

Dependent claims

A plastic film handling apparatus comprising:

an air table defining an enclosure having a top surface and a bottom surface, said top surface having a plurality of spaced openings extending therethrough;
conveyor means extending over said openings in said top surface of said air table for moving a length of plastic film across said top surface of said air table;
a plurality of individual air chambers within said air table communicating with said plurality of spaced openings extending through said top surface of said air table;
pressurizing means connected with said air table for applying a first air pressure level less than atmospheric air pressure to only a first selected number of said individual air chambers and to said conveyor means extending over said openings in said top surface of said air table communicating with said first selected number of said individual air chambers to cause a length of plastic film to adhere by suction to said conveyor means;
electrostatic means extending over said conveyor means and positioned adjacent said first selected number of said individual air chambers for applying a static electric charge to the length of plastic film on said conveyor means to cause the length of plastic film to adhere to said conveyor means after the length of plastic film is moved beyond said first selected number of said individual air chambers by said conveyor means;
a plurality of spaced, parallel partitions extending between said first manifold chamber and said second manifold chamber for defining parallel common walls between said plurality of individual air chambers;
and
a pair of transverse partitions, each partition intersecting an end of each of the plurality of spaced, parallel partitions and defining a common wall between each of said plurality of individual air chambers and one of said first and second manifold chambers.

5 more elements

Dependencies are inferred from the claim text.