Device for unfolding of folded boxes

A device for unfolding of folded boxes, comprising a magazine for receiving of flat folded-box sleeves, a removing device for the individual removal of the folded-box sleeves from the magazine and for feeding the folded-box sleeves to an unfolding station where the folded-box sleeves are partially unfolded along a compressing section. The unfolding device has after the compressing section a chute for the precisely fitting receipt of the partially unfolded folded-box sleeves, an output device to remove the folded-box sleeves from the chute, and an expansion chamber following the chute for receiving the fully unfolded folded-box sleeves in order to achieve a very high unfolding rate.

FIELD OF THE INVENTION

The invention relates to a device for unfolding of folded boxes, comprising a magazine for receiving of flat folded-box sleeves, a removing device for the individual removal of the folded-box sleeves from the magazine and for feeding the folded-box sleeves to an unfolding device where the folded-box sleeves are unfolded along a compressing section.

BACKGROUND OF THE INVENTION

Folded-box blanks made out of cardboard and glued to form sleeves are unfolded with such a device by applying a compressing pressure onto opposite edges of the folded-box sleeves. When unfolding a flat folded-box sleeve, its cross section is changed into a rectangle. The bottom-side face of the folded box is subsequently glued and closed off, the folded box is filled, for example, with a tubular bag, and finally the top-side face is glued and closed off.

Devices are known for unfolding the folded box fully through mechanical pressure along a compressing section, namely until right inner angles exist at all four edges of the folded-box sleeve. Only then is the folded-box sleeve moved on or further processed. The full unfolding, however, takes relatively long. This time requirement is disadvantageous for relatively quick packaging operations.

The purpose of the invention is to avoid a relatively long time for the full mechanical unfolding of a folded-box sleeve and yet achieve fully unfolded folded-box sleeves.

SUMMARY OF THE INVENTION

The purpose is attained by providing a chute following the compressing section for the precisely fitting receipt of the folded-box sleeves which are only partially unfolded at the compressing section, which chute has an output device for removing the partially unfolded folded-box sleeves from the chute, and an expansion chamber following the chute to receive the fully unfolded folded-box sleeves.

The device of the invention has the advantage that a full mechanical unfolding along the compressing section is avoided so that the compressing operation occurs in a shortened time. The precisely fitting receipt in the chute serves, on the one hand, for the partially unfolded folded-box sleeves to be held for a specific time in their unfolded position in order to permit the sleeve material to compensate through suitable forces for the earlier quick unfolding and the related stresses. On the other hand, the chute prevents an independent, full unfolding of the folded-box sleeve, as it would be possible from the there existing material stress. The folded-box sleeves are, after leaving the chute, in a state which results in the expansion chamber in a full unfolding of the folded-box sleeves. The expansion chamber does not have any limitation corresponding to the boundary specified in the chute. Due to the relatively great time savings, since only a partial unfolding occurs along the compressing section, there results a time advantage for the last to occur full unfolding, which time advantage enables a very high unfolding rate (sleeves per second). This rate results from the inertia forces of the flat folded-box sleeves being subjected to a reduced sum of compressing forces along the compressing section. The operation of the chute is optimal in particular at a very high unfolding speed.

When the removing device has several arms each with a suction head, and the arms can be moved by a drive and a planetary gearing along a cycloidal path, it is then possible in a technically simple manner to remove at a top of the cycloidal path a flat folded-box sleeve by means of a suction head from the magazine, and to place same into the chute at another top. The partial unfolding through compressing can then occur along a curve of the cycloidal path along a curved slide surface adapted to the curve. One edge of the folded-box sleeve is hereby pressed against the slide surface.

When the output device has lugs, the lug surface of which corresponds with respect to its alignment to a sidewall of a partially unfolded folded-box sleeve, then the lug surface rests flat on the sidewall during the removal of the folded-box sleeve from the chute, thus does not press said sidewall in and does not influence the unfolding state of the folded-box sleeve.

A very good independent unfolding of the folded box in the expansion chamber occurs when the folded-box sleeve is still lacking 20 to 25 degrees until right angles on its inside are reached. A flat bearing of the lug surface on the sidewall is given for this case when a corresponding angle of 20 to 25 degrees is provided between the lug surface and a normal to a moving endless strand of the output device.

When a first device for forwarding of the fully unfolded folded-box sleeves is provided at the expansion chamber, it is then possible to feed with the device the folded-box sleeves from the expansion chamber to a filling and closing station. When the first device is driven at the same speed as a second device for forwarding, which second device follows the output device, it is then possible for the unfolded folded boxes to be forwarded in a reliable manner simultaneously by lugs of both devices. The forwarding occurs hereby in a careful manner when lugs of both devices hold the folded boxes at diagonally opposite edges of the folded boxes.

DETAILED DESCRIPTION

A device1for unfolding of folded boxes2has a magazine3, in which the prefolded, flat and closed folded-box sleeves4are stored. A removing device5is used to individually remove the folded-box sleeves4from the magazine3and to feed the folded-box sleeves4to an unfolding device6where the folded-box sleeves4are unfolded only partially initially along a compressing section7.

The removing device5has three arms8each with suction heads9. It is moved by a drive10and a planetary gearing11so that reference points13of the arms8describe a cycloidal path12. One flat folded-box sleeve4is thereby removed from the magazine3starting at the point14of the cycloidal path12. Along a curve15of the cycloidal path12occurs a partial unfolding of the flat folded-box sleeves4through compression on a curved slide surface16on which the folded-box sleeves4are moved along with pressure on one of the respective edges17. A further point19of the cycloidal path12is provided at the end of this compressing section7in order to guide the folded-box sleeves4into a chute20. The chute20provides for a precisely fitting receipt of the only partially unfolded folded-box sleeves4.

The folded-box sleeves4keep their form in the chute20and reduce a part of the occurring stress. An output device21is provided to move the folded-box sleeves4through the chute18. The output device21has lugs22each with a lug surface23inclined in the same direction as the sidewall24of the folded box2engaged therewith. An angle α of 22 degrees exists between the lug surface23and a normal25to a moving strand26of the output device21.

An expansion chamber27follows the chute20to receive the partially unfolded-box sleeves4, which unfold further threat due to the box sleeve's residual internal stress and become rectangular unfolded boxes2. Two rotating devices28,29are provided at the expansion chamber27to forward the fully unfolded folded-box sleeves4. The output device21and these two devices28,29hold the unfolded boxes2at diagonally opposite edges17,18in order to forward the unfolded boxes2along a slide surface31to a filling and closing station.

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