Patent Application
20220161514
The present disclosure is directed to an agitator for agitating sheets of material moving through a sheet transport device and to a sheet transport device including the agitator, and, more specifically, to an agitator configured to make direct contact with sheets of material moving through a sheet transport device and to a sheet transport device including the agitator.
Rotary die cut machines may be used to produce flat blanks or sheets of paperboard or other material that are scored so that they can be folded into a finished product, a box, for example. The blanks output from the rotary die cut machine generally must be transferred from the die cut machine to another processing apparatus such as a stacker. A conveyor device referred to as a “layboy” may be placed at the output of the rotary die cut machine to carry the blanks to the stacker.
Rotary die cut machines produce a certain amount of scrap material during operation which consists mainly of the portions of the input material that do not become part of a finished blank. In addition, each blank may include slots or through-openings. The material cut from the blanks to form these slots and through-openings also constitutes scrap.
Most scrap material produced by the die cut machine drops beneath or immediately in front of the die cut machine as it operates. However, it is not uncommon for a material sheet to be cut incompletely so that portions of the sheet that were supposed to be removed wind up traveling into the sheet transport device with the blank. Excessive scrap in the transport path between the sheet transport device and the final stack of blanks may adversely affect the transport of the blanks. That is, the scrap may interfere with the alignment of the blanks or lead to jams. Alternately, if the scrap is carried all the way through the stacker and into the final stack of blanks, the blanks in the stack will have gaps therebetween where the scrap material is present thus resulting in a crooked, or oversized or non-uniform stack of blanks. Some scrap may even end up inside a finished box formed from the cut blanks; this is generally undesirable to most end customers and must be completely avoided in some applications, such as boxes for use to package food.
It is known to use an agitator to repeatedly impact the bottoms of the lower belts of a layboy to shake some of the scrap material from the sheets traveling through the layboy. A layboy 10 having a conventional agitator 12 is illustrated in
The agitator 12 is mounted to the layboy 10 inside the closed path formed by the lower belts 20 and comprises a central shaft 30 having an axis of rotation 32 transverse to the sheet transport direction 24. A first support disk 34 is mounted at one end of the shaft 30, a second support disk 36 is mounted at the opposite end of the shaft 30 and middle support disk 38 is mounted in the middle of the shaft 30. The first, second and middle support disks 34, 36, 38 are each provided with a plurality of bosses 40, and a first plurality of tubes 42 are journaled on the bosses 40 so that they extend between the first support disk 34 and the middle support disk 38, and a second plurality of the tubes 42 are journaled on the bosses 40 so that they extend between the middle support disk 38 and the second support disk 36. The tubes are freely rotatable on the bosses.
The central shaft 30 is mounted relative to the upper portions of the lower belts 20 so that at the central shaft 30 is rotated, the tubes 42 periodically impact against the bottoms of the upper portions of the lower belts 20. These impacts cause the lower belts to rise and fall and shake the sheets as they move over the agitator 12 to dislodge scrap material therefrom.
While such agitators are useful, the fact that the sheets are in contact with upper and lower sets of belts as they travel through a layboy complicates the removal of scrap, especially scrap that is held against the sheets by the belts. It is therefore known to include an additional sheet transport device between a layboy and a stacker to remove additional scrap from the sheets of material. One such sheet transfer device is disclosed in U.S. Pat. No. 10,071,873, assigned to the present applicant, which is incorporated herewith in its entirety. This device uses wheels instead of belts to support the bottoms of the sheets, and the wheels make it easier to remove scrap from the sheets. Fans and/or brushes may also be used to dislodge loose or partially attached scrap material. It would be useful to agitate the sheets as the travel through such a sheet transfer device. However, the lack of belts and the close spacing of the support wheels means that a conventional agitator as discussed above cannot be used.
It would therefore be desirable to provide an agitator that is suitable for use with sheet transport devices that do not use belts to form the upper and/or lower guide sections of the device and a sheet transfer device that include such an agitator.
These and other problems are addressed by embodiments of the present invention, a first aspect of which comprises an agitator for agitating sheets of material passing through a sheet transport device in a sheet transport direction from an input end to an output end, the sheet transport device having an upper guide section comprising a first plurality of wheels or belts and a lower guide section comprising a second plurality of wheels or belts, the upper and lower guide sections defining a sheet transport path therebetween. The agitator comprises a set of first rollers each having a roller axis of rotation and a first width, the first rollers being mounted to at least one first holder such that the axes of rotation of the first rollers are radially spaced from a line and such that rotating the at least one first holder around the line causes the set of first rollers to orbit around the line, and a set of second rollers each having a roller axis of rotation and a second width, the second rollers being mounted to at least one second holder such that the axes of rotation of the second rollers are radially spaced from the line and such that rotating the at least one second holder around the line causes the set of second rollers to orbit around the line. The agitator also includes at least one support supporting the at least one first holder and the at least one second holder for rotation around a line, and the set of first rollers is spaced from the set of second rollers in the direction of the line by a distance greater than the first width.
Another aspect of the invention comprises a sheet transport device for carrying sheets in a sheet transport direction from an input end to an output end. The sheet transport device includes an upper guide section comprising a plurality of upper wheels or upper belts and a lower guide section comprising a plurality of lower wheels, the tops of the lower wheels being bounded by a first imaginary plane. The lower surfaces of the upper wheels or belts and the first imaginary plane defining a sheet transport path therebetween. The device also includes an agitator configured to agitate the sheets in the sheet transport path. The agitator includes a set of first rollers each having a roller axis of rotation and a first width, and the first rollers are mounted to at least one first holder such that the axes of rotation of the first rollers are radially spaced from a line and such that rotating the at least one first holder around the line causes the set of first rollers to orbit around the line. The agitator also includes a set of second rollers each having a roller axis of rotation and a second width, and the second rollers are mounted to at least one second holder such that the axes of rotation of the second rollers are radially spaced from the line and such that rotating the at least one second holder around the line causes the set of second rollers to orbit around the line. At least one support supports the at least one first holder and the at least one second holder for rotation around the line, and the at least one support is located at a lower side of the sheet transport path. The first set of rollers and the second set of rollers and the at least one support are arranged and configured such that the rollers of the first and second sets of rollers pass through the first imaginary plane and into the sheet transport path when the first holder and the second holder rotate around the line.
These and other aspects and benefits of the disclosure will be better understood after a reading of the following detailed description in connection with the attached drawings in which:
Referring now to the drawings, wherein the showings are for the purpose of illustrating presently preferred embodiments of the invention only and not for limiting same,
A drive 66 is operably connected to the shaft 62, by a belt or chain 68, for example, to rotate the shaft 62 in the first and second bearings 58, 60 and the intermediate bearings 64. The drive is supported by the support beam 52 so that the entire agitator 50 can be installed as a unit.
A plurality of roller sets 70 are mounted along the shaft 62. Each of the roller sets 70 comprises first and second spaced roller plates 72 fixedly mounted to the shaft 62 for rotation therewith and a set of rollers 74 supported by the roller plate 72 for free rotation relative to the roller plates 72. Each pair of the first and second spaced roller plates 72 may sometimes be referred to herein as a “holder” for the rollers.
The agitator 50 is mounted in a sheet transport device 82 as illustrated in
The shaft 62 of the agitator 50 extends transversely to the sheet transport direction and is mounted relative to the imaginary plane 88 such that the imaginary circle bounding the rollers 74 intersects the imaginary plane 88. In other words, portions of the rollers 74 travel through the imaginary plane 88 as the shaft 62 rotates. The shaft 62 is preferably mounted between pairs of the support axles 87 in the sheet transport direction so that the shaft 62 and the support axles are approximately the same distance below the imaginary plane 88. The imaginary circle overlaps the lower wheels 86 when viewed in a direction of the shaft 62, that is a direction perpendicular to the sheet transport direction.
In operation, the upper belts 84 and the lower wheels 86 of the sheet transport device 82 are operated in a conventional manner to carry sheets of material along the sheet transport path. During this operation, the agitator 50 operates, as discussed below, to jostle the sheets in the sheet transport path to dislodge scrap material therefrom. Specifically, the drive 66 is operated to cause the shaft 62 to rotate, preferably so that the top of the shaft 62 moves in a direction opposite to the direction of rotation of the lower wheels 86, and this causes the rollers 74 to orbit around the axis of rotation of the shaft 62. At top of their orbits, the rollers 74 extend through the imaginary plane 88 and directly impact against sheets of material traveling through the sheet transport device 82.
The rollers 74 are lightweight and preferably have a narrow width relative to the width of the sheets being transported and they therefore have a relatively low moment of inertia and require little energy to be set in motion. Therefore, when the rollers engage the bottoms of the sheets moving along the sheet transport path they do not interfere significantly with the forward movement of the sheets or damage the surfaces of the sheets. Instead, the rollers 74 rotate when they contact the moving sheets to allow the sheets to continue forward with relatively little resistance while the vertical component of the force imparted to the rollers by the rotation of the roller supports jogs the sheet upward to loosen and/or dislodge material therefrom. If a brush 92 is present, it is preferably located above the agitator 50 and cooperates with the agitator to loosen and remove scrap material. In this manner, all or at least a greater percentage of any scrap in the sheet transport path can be removed that would have been removed by a conventional layboy using a conventional agitator.
The present invention has been described herein in terms of a presently preferred embodiment. Modifications and additions to this embodiment will become apparent to persons of ordinary skill in the art upon a reading of the foregoing description. It is intended that all such modifications and additions form a part of the present invention to the extent they fall within the scope of the several claims appended hereto.
