Package making – Methods – Closing package or filled receptacle
Reexamination Certificate
2001-10-19
2003-11-11
Gerrity, Stephen F. (Department: 3721)
Package making
Methods
Closing package or filled receptacle
C053S376500, C053S377400
Reexamination Certificate
active
06643997
ABSTRACT:
This application is filed under the provisions of 35 U.S.C. §371 and claims the priority of International Patent Application No. PCT/DE00/00323 filed Feb. 3, 2000, which in turn claims priority of German Patent Application No. 199 04 429.5 filed Feb. 4, 1999.
The invention relates to a process for adjusting the volume of a collared sack or bag, incompletely filled with bulk material, the collar of which is formed by two mutually opposed first peripheral strips, folded outwards, and two mutually opposed second peripheral strips, folded inwards, to the volume of the bulk material located in the sack or bag. The invention further relates to a device for the performance of this process and a sack or bag which can be used in this situation.
The advantage with the use of valve sacks or bags lies in the low emergence of dust during filling and in the good stacking and palletising characteristics. However, when being filled with a bulk material of fluctuating density a valve sack or bag is often incompletely filled when the density of the bulk material rises. The consequence of the incomplete filling of the sack or bag is air in the head of the sack or bag above the bulk material. The enclosed air has a sponge-like effect on the contents of the sack or bag. Safe and reliable palletising and handling of such sack or bags is not possible.
With an open sack or bag, the filling speed can be substantially increased in comparison with that of a valve sack or bag. The emergence of dust, however, is considerable unless special measures are taken. If an open sack or bag is used with the length required for the greatest possible filling volume, then, after filling with a bulk material of greater density and correspondingly less filling volume than is inherently provided for, the sack or bag is pressed together and the sack or bag length reduced by cutting off the overlap, to the dimension necessary for reliable closure. The sack or bag which is adjusted in this way to the filling volume is difficult to load on pallets, since it may have a flat bottom, but on the top it is generally wedge-shaped.
From DE 198 40 792.0 and 198 40 793.9 a collared sack or bag is known, as well as a process and device for transporting, checking, filling, and closing a collared sack or bag. This sack or bag combines the advantages of the open sack or bag and the valve sack or bag, in that it is characterised by a large filling cross-section and the possibility of a dust-tight closure during the filling process. Due to the partial closure which is already effected before filling, however, this sack or bag is designed for a specific volume, which cannot be adjusted. Accordingly, if the density of the bulk material rises above the value provided for, this sack or bag too will only be incompletely filled. It may therefore have similarly disadvantageous handling properties as the incompletely filled valve sack or bag.
DE 198 40 793 A1 relates to a process and device for transporting, checking, filling, and closing a sack or bag. The sack or bag features a sack or bag body capable of being spread to form a rectangular cross-section, formed of two wide first sack or bag walls and two narrow second sack or bag walls, a sack or bag base closed at the bottom, a sack or bag opening delimiting the sack or bag body at the top, and an open sack or bag closure arrangement, whereby the sack or bag closure arrangement comprises in turn first closure flaps, which in each case connect to the first sack or bag walls and project outwards at right angles to the first sack or bag walls, horizontally from the sack or bag opening, two closure flaps, which in each case connect to the second sack or bag walls, and which fold over inwards onto the sack or bag opening, lying horizontal, so that the first closure flaps and the second closure flaps form a frame-shaped sealing collar lying in a horizontal plane, in which the outer areas of the first closure flaps are retained by conveying media capable of being actuated by a drive.
The present invention is based on the problem of creating a process for adjusting the volume of a filled collared sack or bag to the volume of the bulk material contained in the sack or bag, so that handling disadvantages as a consequence of incomplete filling or of a volume of air in the head of the sack or bag are avoided with this sack or bag. In addition, good retention of the closure should be achieved, despite the reduction in the volume or the reduction of the sack or bag length. In addition to this, the advantages of the collared sack or bag in comparison with the valve sack or bag and the open sack or bag should be retained, i.e. a sack or bag should be created which, in addition to a large filling cross-section and a dust-tight closure, also allows, during filling, for a reduction of the sack or bag volume to the filling volume actually contained. In addition, a sack or bag should be created which, despite the adjustment of the volume, has good palletising properties. In particular, the cutting of sack or bag material and therefore the loss of material should be avoided. A device should also be created for adjusting the volume of a collared sack or bag, which can be integrated into a continuously operating filling system for collared sack or bags. Finally, a new sack or bag should be created which is capable of being easily handled during the preparation for filling, during the filling itself, and during the following process stages, in particular during closing. This sack or bag should be created in such a way that it can be filled without any emergence of dust, and the closure surfaces of the sack or bag (by adhesive bonding or welding) are not impaired by layers of dust. The sack or bag should therefore be capable of being well sealed in a simple manner, for preference on a flat surface. Finally, a sack or bag should be created of which the closure volume is capable of being adjusted to the actual filling volume.
This problem is resolved according to the invention by the process referred to in the preamble, in that the first peripheral strips are drawn apart from one another, and, in this situation, the sack or bag wall of the upper part of the sack or bag, which remains unfilled, is drawn over the fold edges into the collar, or the sack or bag cross-section is reduced by pressure on the larger mutually opposed sack or bag wall parts. To draw the first peripheral strips apart, they are in general gripped in the centre. For preference, they are drawn apart at right angles to the mid-plane of the sack or bag, or to the sack or bag wall connected to the first peripheral strips. Other drawing angles are also possible. As a departure from the open sack or bag, with the overlap being cut off, the unfilled and therefore superfluous part of the sack or bag is transformed into the sack or bag collar, to that this gains in its width what the sack or bag loses in its length. In this situation, at the same time the free cross-section of the sack or bag opening is reduced, and the initially unfilled sack or bag volume disappears.
Due to the central engagement at the first peripheral strips, the shortening of these strips with the corresponding lengthening of the second peripheral strips is in general possible without hinderance by the engaging grip elements. The first peripheral strips are in general drawn apart in opposite directions. From the widened collar, the closure is formed, which acquires added resistance and stability in comparison with a non-widened collar. When the strips are drawn apart, the folding edges are displaced towards the base of the sack or bag. As the cross-section of the sack or bag diminishes due to the pressing on its broad sides, the level of the filling material rises, as a result of which the upper air pockets disappears. This design requires a sufficient flow capacity of the filling material, so that the sack or bag does not tear at the side.
According to a preferred embodiment of the process according to the invention, at the same time as the first peripheral strips are drawn apart the ba
Oster Robert
Schwenke Dieter
Tegtmeyer Jurgen
Chronos Holdings Ltd.
Durand Paul
Fuierer Marianne
Gerrity Stephen F.
Hultquist Steven J.
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