Sheet feeding or delivering – Feeding – Separator and conveyor
Reexamination Certificate
2000-01-31
2001-08-28
Skaggs, H. Grant (Department: 3651)
Sheet feeding or delivering
Feeding
Separator and conveyor
C271S011000, C271S010040, C271S095000
Reexamination Certificate
active
06279894
ABSTRACT:
The invention relates to a device for separating stacked flat bag pieces provided with socalled side folds, comprising a supporting structure, which is pivot-mounted in a frame and is provided with a drive, and on which rollers, provided with a row of suction elements at equal angular distances, are mounted so as to rotate on a cylindrical enveloping surface, which is concentric with respect to the supporting structure's axis of rotation. The rollers' drivers are driven by way of intermediate wheels, mounted in the supporting structure, by a stationary central wheel, whose direction of rotation is opposite to the supporting structure's direction of rotation. The device also comprises a stacking cassette, which is positioned in such a manner at the enveloping cylinder, described by the row of suction elements, that each roller's row of suction elements pulls the first bag piece out of said cassette. Finally the device comprises a conveyor, which is positioned at the enveloping cylinder, accepts the individual workpieces and carries them away.
Socalled rotary feeders of this type are known, for example, from the DE-PS 12 77 655 and the DE 196 05 461 A1. These rotary feeders serve to separate flat workpieces, for example bag segments, which are inserted into a stacking cassette for the manufacture of bags or sacks. If bag pieces, intended for the manufacture of bags or sacks, are separated using rotary feeders, the stacks of bag segments are inserted into the stacking cassette at right angle, since the rotary feeders would have to exhibit much larger dimensions if the bag pieces were to be inserted into the stacking cassette lengthwise in the rotary feeder's direction of rotation. If flat lying bag pieces, exhibiting no side folds, are to be separated using a rotary feeder, there are no problems because the bag pieces can be pulled out of the stacking cassette cleanly and smoothly by means of rows of suction elements, which engage with the individual bag pieces in the area of a side edge. However, such a removal of perpendicularly inserted bag pieces, provided with side folds, is not possible because the rows of suction elements would engage only with one fold of the side edge and the other trailing side edge could bend or skew, thus preventing a clean, crumple-free removal.
Therefore, the object of the invention is to provide a device of the type described in the introductory part, with which stacks of bag segments, provided with side folds, can also be separated without the anxiety that the trailing side fold will fold over, skew or crease.
The invention solves this problem in that the stacking cassette holds bag pieces exhibiting cut edges, which face outwardly in the direction of the axis of rotation and are provided with socalled offset cuts and that the stacking cassettes and/or the suction elements are arranged in such a manner and/or the suction elements are controlled in such a manner that an outer suction element of each row of suction elements sucks in each bag piece at one end of the layer of the offset cut that overlaps the layer facing the suction element, and the other suction elements engage with the edge of each bag piece that is provided with a side fold at an interval in time relative to the first suction element.
It has been demonstrated surprisingly that with the device of the invention stacks of bag pieces, provided with side folds, can be separated flawlessly and the individual bag pieces can be fed to the next processing step. The flawless function of the device according to the invention is based presumably on the fact that because each bag segment to be pulled off is picked up first by an outer suction element at the end of an overlapping layer of an offset cut and is carried along, said bag segment to be pulled off experiences a certain convexity due to the circular motion of this suction element, a state that results in a stiffening of the edge region of the bag segment provided with side folds so that the trailing edge of the bag can no longer unfold when only the overlapped side fold is picked up in its edge region by the following suction element, thus after a time delay.
A preferred embodiment provides that the suction elements of each row lie on a line that together with the axis of rotation of the roller or roller disks carrying the suction elements encloses an acute angle and that the edges of the sides of the bag pieces to be pulled off are held parallel to this line in the stacking cassette. In this embodiment a first suction element of each row of suction elements is assigned in such a manner to one end of an overlapping layer of the offset cut of a bag piece, provided with side folds, that this end is picked up first and the next following suction elements of the row in turn engage with the edge of the bag piece, provided with a side fold. In this embodiment there is no need for the suction air stream of the suction elements to be controlled especially with respect to time.
The acute angle between the axis of rotation of the roller(s), carrying the suction elements, and the line of the suction elements ranges advantageously from approx. 4° to 12° and is preferably approximately 8°.
REFERENCES:
patent: 3720409 (1973-03-01), Kubo et al.
patent: 4542894 (1985-09-01), Feldkamper et al.
patent: 5080341 (1992-01-01), Lüthy
patent: 5169285 (1992-12-01), Müller
patent: 5174559 (1992-12-01), Diamantides
patent: 1202290 (1965-02-01), None
patent: 0405107 (1991-01-01), None
Jacobson & Holman PLLC
Skaggs H. Grant
Windmoller & Holscher
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