Package making – Methods – Conforming by stretching or shrinking of cover over contents
Reexamination Certificate
1999-11-03
2001-10-09
Sipos, John (Department: 3721)
Package making
Methods
Conforming by stretching or shrinking of cover over contents
C053S459000, C053S557000, C053S567000
Reexamination Certificate
active
06298636
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a method and an apparatus for packaging an object as defined in the preamble of claim
1
or as defined in the preamble of claim
13
, Such a method and a corresponding apparatus are in particular used for packaging of stacks of goods which are arranged on a pallet and are to be transferred in any form or other. Due to the foil hood the stack of goods is protected against atmospheric exposure and is given increased stability.
In known methods and apparatuses for packaging objects, in a first treatment step a foil hose in desired length is supplied into a treatment room, is welded into a foil hood and the formed foil hood is cut off. Subsequently, the foil hood is opened and with the aid of grippers of the shrink frame is drawn over the object to be packaged. For shrinking the foil hood onto the object, the shrink frame including a heating means annularly enclosing the object to be packaged, thereafter is moved from the bottom range of the object further again in upward direction. Therein the heating means is switched on so that the foil hood is shrunk onto the object to be packaged under supply of heat.
This method and the corresponding apparatus are quite limited in capacity as the individual method steps are carried out subsequently such that the gripper means at first pulls the foil hood over the object completely before the shrink frame located in the bottom area of the object can start with the shrinking operation. Only after the shrinking operation the packed object is transferred further and the next unpacked object is moved into the apparatus. The cycle time of such a known apparatus, therefore, is comparatively long, this rendering it comparatively expensive in relation to the number of packed objects per unit time.
Furthermore, no particular shrinking quality is achieved. Finally, it is not guaranteed that the foil of already shrunk goods of the objects to be packaged does not glue together with the shrink foil. In order to avoid such pasting together, pressure blowers are proposed which blow up the foil hood in order that the latter does not directly bear on the object. The control of such blowers, however, is very expensive and there exists the danger that the foil hood due to too strong blowing up comes too close to the shrink frame and, therefore, due to too strong heating of the foil hood holes are burnt into the foil hood.
SUMMARY OF THE INVENTION
It is, therefore, the object of the present invention to create a method and an apparatus for packaging an object, in which the output is increased with simultaneously avoiding a pasting together of the foil hood and undesired creation of holes in the foil hood and/or an undesired creation of folds in the foil hood.
This object is solved with a method in accordance with the features of claim
1
and with an apparatus in accordance with the features of claim
13
. Preferred embodiments of the invention are disclosed in the depending claims.
In accordance with the method according to the present invention, the foil hood is shrunk when being pulled over the object to be packed. Thereby, the two method steps of pulling over and shrinking are combined chronologically such that the cycle times of the method are shortened and the capacity is increased. Furthermore, the removal by suction of the air or the blowing up of the foil hood can be done without during shrinking since shrinking takes place while the foil hood is pulled over the object. This also permits a particularly uniform and reliable shrinking of the foil material, wherein creation of folds is avoided.
In a preferred embodiment of the present invention, the toil hood is shrunk onto the object by means of a heating means by supply of heat above a gripper means. This permits an efficient and continuous shrinking operation, as during shrinking the heating means can be positioned with a fixed distance to the gripper means and the foil wall.
Preferably, the foil hood is charged with heat, before it comes into contact with the object such that the pulling-over operation of the foil hood over the object essentially occurs without contacting. This avoids possible damages, like fissures or the like, during pulling-over of the foil hood. Furthermore, the foil hood can be shrunk onto the object without creation of folds, this improving its mechanical properties, the resistance to tearing in particular.
In a preferred embodiment of the present invention, heat supply during shrinking of the foil hood is controllable such that objects with irregular surfaces can be shrunk better. In case of irregular surfaces the distance of the foil hood to the heating means varies such that an individual adaptation of heat supply is required for certain areas.
In accordance with a particularly efficient method, at first the foil hood is shrunk onto the object on its upper side and subsequently the heating means is moved in downward direction together with a gripper means maintaining the foil hood in reefed condition. This results in a particularly solid seat of the foil hood on the object.
A further increase in output can be reached when the foil hood is opened by a first gripper means and then is transferred to a second gripper means. Said second gripper means together with the heating means then can initiate the shrinking operation while said first gripper means can take up the subsequent foil hood and bring it into the reefed condition.
In a preferred embodiment, the foil hood is sucked to the inside on the bottom side of the object and at least partly is shrunk onto the bottom side of the object such that the seat of the foil hood becomes particularly solid. For a further increase in stability, the foil hood can be welded together with a bottom foil in its lower region. Thereby, also a sealed packaging of the object can be achieved. In order to make the cycle times as short as possible, the foil hood can be cooled in the heated shrunk area. This permits a particularly high heat supply in short time as the excess heat can be carried off quickly.
In accordance with the apparatus according to the present invention, during pulling-over of the foil hood over an object the heating means is arranged with a fixed distance above a gripper means for pulling over the foil hood. This permits simultaneous pulling-over of the foil hood and shrinking of the latter onto the object. In addition, a reliable and quick shrinking can be carried out as the distance of the foil hood to the heating means is comparatively uniform, in case of objects with irregular surfaces in particular. This permits foodless shrinking and making available of a shrunk foil hood capable of bearing.
In a preferred embodiment of the apparatus according to the present invention, the gripper means for pulling over the foil hood can be coupled to the shrink frame or is connected thereto. In both cases, the distance of the gripper means to the heating means on the shrink frame can be fixed quickly and in simple manner.
Preferably, the apparatus comprises a first movable gripper means for opening the foil hood and a second movable gripper means for pulling over the foil hood such that the gripper means can work in parallel and are adapted to their respective tasks individually. In particular, the first gripper means can comprise several suction boxes for opening the foil hood, whereas the second gripper means can be connected to the shrink frame.
In accordance with a preferred embodiment of the invention, the shrink frame in addition to the heating means also comprises a cooling means by which rapid cooling down of the foil hood is achieved after shrinking. This permits an intense heat supply and a temporal shortening of the shrinking operation.
Preferably, a heat shielding is provided for between said first gripper means and said second gripper means such that the opening of the foil hood can take place in a comparatively protected cooler room and pasting of the subsequent foil can be avoided.
REFERENCES:
patent: 4473990 (1984-10-01), Thimon
patent: 4563689 (1986-01-01), Hannen
pa
Lachenmeier Kurt
Thomsen Flemming
KL-Lachenmeier A/S
Pearne & Gordon LLP
Sipos John
LandOfFree
Method and apparatus for packaging an object does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for packaging an object, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for packaging an object will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2563589