It has been known to provide surface coatings to containers as they are moved in rows that extend transversely of a conveyor on which they are supported by providing an overlying spraying apparatus that is moved transversely to the direction of movement of the rows of the containers.
In such apparatus, it is conventional to utilize gearing or chains to move the spray apparatus such as guns transversely of the conveyor. Such apparatus uses a large number of parts, requires substantial time for installation, is expensive to manufacture and maintain and requires complex controls.
It is also known to use a rodless cylinder supported at each end on a carriage with means on each carriage for shifting the angle of the cylinder relative to the direction of movement of the conveyor. The control of this type of apparatus is diffcult and imprecise in ensuring that the spray apparatus moves between the rows of containers as they are moved by the conveyor.
Among the objectives of the present invention are to provide a method and apparatus which overcomes these disadvantages and provides a system for moving spray guns transversely; which provides more accurate movement and control of the spray pattern such that the coating is applied to the surface of the container between the moving rows of containers; which permits acceleration and deceleration from each end of the stroke of the apparatus transversely; which requires minimum maintenance; and which can be utilized in either a continuous mode or a row follower mode.
In accordance with the invention, a method and apparatus is provided for spraying the surfaces of glass containers which are being moved in longitudinally spaced rows by a conveyor wherein a rodless air cylinder is mounted transversely of the conveyor and the spraying apparatus is connected to the piston of the rodless cylinder so that the spraying apparatus is moved transversely of the rows of containers. The rodless cylinder is supported for pivotal movement about a vertical axis so that the axis of the cylinder may be moved to a position other than a right angle to the longitudinal axis of movement of the conveyor. The offset of the angle from a right angle and the speed of traverse of the piston is coordinated with the conveyor speed so that any time during the travel, the spray apparatus is spraying between the rows being sprayed.