Background of the Invention
This invention relates to a device to control the lateral alignment of a continuous moving web of material and more particularly, to a device to control the lateral alignment of a continuous moving web of material by pivoting a guide roller at an angle to its normal position.
In the printing and stamping arts, among others, certain operations are performed on continuous webs of material which often move through machines at high speed. Accurate alignment of the web is usually required during such operations. However, the moving web often shifts from its proper lateral position on the rollers and guides supporting it, due to imperfections in the web or machinery. Displacement of the web from its true lateral position interferes with the operations being performed on the web and often results in spoilage or a defective product. Prior art devices designed to accurately adjust the lateral position of a continuous web are complicated in construction and entail considerable manufacturing expense. Thus, there is a need for a simple device which is easy to manufacture and can accurately adjust the lateral position of a moving web of material.
Accordingly, a primary object of my invention is to provide a new and improved device to control the lateral alignment of a continuous moving web of material.
Another object of my invention is to provide a device to control the lateral position of a continuous moving web of material by pivoting a guide roller at an angle to its normal position.
A further object of my invention is to provide a device capable of accurately controlling the lateral position of a web of material moving at a high speed.
Still another object of my invention is to provide a device to control the lateral position of a moving web of material which is simple in construction and easy to manufacture.
In the preferred embodiment of my invention; a guide roll is rotatably mounted on a support shaft which extends between two laterally-spaced arms. A continuous moving web of material passes over the guide roll in a 90.degree. wrap. A first pivot arm extends downward from a drive motor and is adapted to rotate in a vertical plane about a pivot point on the drive motor when the motor is actuated. The first pivot arm includes an aperture aligned with the axis of the support shaft and is adapted to receive an end of the support shaft in a loose fit, whereby the support shaft can be pivotally mounted in the aperture for limited pivotal movement. The second pivot arm is adapted to pivot in a vertical plane about a second pivot point offset 90.degree. from the first pivot point. A scanner assembly extends between the two pivot arms in close proximity to the guide roll and is designed to detect lateral misalignment of the moving web of material passing over the guide roll. When misalignment is detected, the scanner assembly activates the drive motor to pivot the guide roll from its position normal to the path of the moving web. The web is thus shifted back into proper lateral alignment.
Brief Description of the Drawings
FIG. 1 is a front elevational view of the disclosed invention;
FIG. 2 is a side elevational view from the drive side of the disclosed invention; and
FIG. 3 is a side elevational view of the disclosed invention;
Detailed Description of the Invention
As shown in FIG. 1, a web guide system constructed in accordance with my invention comprises guide roll 10 and drive motor 12, employed to pivot guide roll 10 from its normal position. Chassis or frame 50 has a pair of spaced parallel side plates 52, 54. Mounted on the frame 50 and dependant therefrom is the motor 12, which is positioned adjacent side plate 54.
Guide roll 10 is rotatably supported by shaft 14, which is hinged to pivot arms 16 and 18. Pivot arm 16 extends downward from drive motor 12 and is pivotally connected to motor 12 at pooint 20, whereby it may be pivoted forward or backward by motor 12 about point 20, as shown in FIG. 1.
On the end of shaft 14 opposite pivot arm 18, a bearing surface 21 is formed out of a cross-sectional circular segment of shaft 14 along a diameter of shaft 14. Bearing surface 21 rests adjacent surface 23 of arm 16, which pivots about pivot 20 on pivot shaft 25 in a vertical plane parallel to plate 54. Pin 24 extends through shaft 14 and aperture 22 of arm 16, permitting shaft 14 and roller 10 to pivot about pin 24 in a vertical plane perpendicular to plate 54. Thus, when arm 16 is pivoted, shifting the position of shaft 14, shaft 14 will pivot about pin 24.
On the end of shaft 14 opposite arm 16, a bearing surface 26 is formed out of a cross-sectional circular segment of shaft 14 along a diameter of shaft 14. Bearing surface 26 rests adjacent surface 28 of L-shaped pivot arm 18. Pivot arm 18 pivots on pivot shaft 27, which depends from plate 52 at point 30, in a vertical plane parallel to plate 52. The axis of pivot shaft 27 is offset 90.degree. from the axis of pivot shaft 25 in a counterclockwise direction along a quarter circle arc.
Pin 32 extends through aperture 34 in shaft 14 and aperture 36 of arm 18, permitting shaft 14 and roller 10 to pivot about pin 32 in a horizontal plane perpendicular to plate 52. Thus, when arm 16 is pivoted by motor 12 through a small arc, shifting the vertical and horizontal position of shaft 14 and roller 10, shaft 14 can pivot freely about pin 32 and arm 18 can pivot about point 30.
Scanner assembly 38 comprises scanner units 39 and 41 supported by rods 43 which extend between arms 16 and 18. Scanner units 39 and 41 are conventional electric eye apparatus which comprise a light source and a light-sensitive voltage cell. The scanner assembly 38 moves as a unit with guide roller 10.
In operation, web 40 runs over guide roller 10 in a 90.degree. wrap and passes through scanner units 39 and 41 of assembly 38. When the web shifts its lateral position and becomes misaligned, the electric eye of either unit 39 or 41 will be activated depending on whether the web 40 shifts to the right or the left. Drive motor 12 is activated by the scanner unit and arm 16 is then pivoted either forward or backward, depending on whether the web has shifted to the right or left, causing shaft 14 and roller 10 to move either forward or backward on the drive side of the system while pivoting about pin 32 on arm 18. Shifting the horizontal and vertical position of guide roll 10 will cause web 40 to shift laterally on guide roll 10 to the right or left, depending on whether arm 16 is pivoted forward or backward. Hence, in this manner, misalignment of moving web 40 is compensated for by shifting web 40 back into its proper lateral position. When the web returns to its proper position, scanner assembly 38 will deactivate drive motor 12 and return guide roll 10 to its original position to accomodate the shift in position of shaft 14.
While the principles of my invention have been described above in connection with specific embodiments and applications, it is to be understood that this description is made only by way of example and not as a limitation on the scope of the appended claims.