GB2277507A

GB2277507A - Folding apparatus for folding wrappers around articles

Info

Publication number: GB2277507A
Application number: GB9408611A
Authority: GB
Inventors: Klaus Hesse; Heinz Lauerbach; Wilfried Seibt
Original assignee: PACTEC DRESDEN GmbH
Current assignee: PACTEC DRESDEN GmbH
Priority date: 1993-05-01
Filing date: 1994-04-29
Publication date: 1994-11-02
Also published as: BR9401028A; GB9408611D0; ITRM940252A1; RU94015278A; JPH0752921A; DE4314142C1; ITRM940252A0

Description

1 i -1 2277507 FOLDING APPARATUS FOR FOLDING WRAPPERS AROUND ARTICLES The

present invention relates to apparatus for folding wrappers around articles, for example to form small bags or baskets.

Known folding apparatus for this purpose comprises a continuously rotating gripper head rotor and an equally rotating packing head rotor, both rotors being equipped with retaining elements pairs. Folding stations, at which the articles to be wrapped are guided past and the required folds are produced one after the other, are arranged in fixed locations in a housing of the apparatus. In addition, means are provided for the transfer of the partially folded pack to the packing head rotor, which is associated with equipment for the production of a rotary wrap. One widely used form of equipment for the production, after folding, of bags or baskets comprises a singling disc, which is switched in steps, in a packaging machine. In that-case, sweets or pieces of confectionery to be wrapped are fed to peripherally arranged receptacle pockets of the disc. A stroke plunger engaging through the pockets brings the sweets, together with the wrapper sheets, into a revolver head of the packaging machine. Side folding is carried out during the stroke travel. An accompanying folder produces end face folding. The thus partially folded wrapper is now seized by retaining cheeks of the revolver head. A slide draws in a base fold and an inner fold is applied after its return. A finishing fold is formed during further switching of the revolver head. At the opposite side, a tube has formed, which envelopes the sweet at four 1 sides and is turned in in a sequential station.

Due to the acceleration and air resistance, instabilities of the wrapper sheet occur. It is therefore proposed in DD PS 125 664 to employ a fork-shaped supporting part for retention of the wrapper.

It is a disadvantage of the various apparatus that the intermittently operating plunder with the long stroke required for the folding sequences as well as the short movement times for the end face and base folder limit the performance of the packaging machine due to dynamic loading of the mechanisms.

An automatic rotary wrapping machine for the wrapping of pieces of confectionery and sweets, by which a higher performance is achievable, is described in DE-OS 22 54 659. In that case, the pieces of confectionery or the sweets are also advanced on a singling disc. Take-off from the singling disc, however, is effected by grippers of a rotary wheel which withdraws the pieces of confectionery from peripherally arranged receptacle pockets. At the same time covering of the piece of confectionery is effected by a wrapper advanced by another rotary wheel. The piece of confectionery with the wrapper is now guided past a stationary guide plate so that a part of the wrapper is laid around the piece of confectionery. Wrapping flap members stabilise this position, whilst further guide plates turn over side folds. Grippers of a following rotational wheel seize the piece of confectionery at the sides now covered by the wrapper. In the case of further travel, the protruding sides are folded over by a stationary flap apart and a stationary guide plate. In the further course, the opposite side is closed by a rotary fold and the wrapping is thus completed.

A disadvantage of this machine is -that the stationary folding elements, such as guide plates, wrapping flap members and so forth are not suitable for turning over folds in the higher performance range. The folding paths are too short and folds have to be performed in different directions, so that the mechanical effects on the wrapper at higher speeds of the packaging machine can lead to faulty functioning or even destruction of the wrapper.

In order to avoid this disadvantage, there is disclosed in DEOS 39 24 552 a continuously operating sweet wrapping machine in the high performance range. This consists of a rotary head which is arranged beside a wrapping wheel, rotates at the same peripheral speed and is equipped with folding elements. The rotary head has the same number of folding stations as holding element pairs at the wrapping wheel. Each folding station comprises three folding elements which, one after the other, produce appropriate folds. A rotary fold is executed on the opposite side of the sweet and the folding is thus produced completely during one revolution.

This machine has the disadvantage that a high technical expenditure i s required for its realisation. Several folding stations are arranged at the rotary head and the courses of movement of the folding elements of each folding station must be matched to each other by corresponding gears. The folding elements come into engagement one after the other. Although this reduces the loading of the packing means, it can lead, particularly in the case of elastic materials, to an already formed fold springing open before the next fold is laid thereover. This effect is promoted by the round shapes of the articles to be wrapped as the formation of sharp and constant folds is made more difficult by this shape.

There is thus a need for folding apparatus which may function reliably even in the high speed range with relatively little technical complication. Preferably, already produced folds shall be held securely by subsequent folds and the influence of the different shapes of articles and different qualities of wrappers shall be reduced or eliminated.

According to the present invention there is provided folding apparatus for the folding of a wrapper for the formation of small bags or baskets, comprising a continuously rotating gripper head rotor, an equally rotating packing head rotor, the rotors being equipped with retaining element pairs, folding stations which are arranged in fixed locations in the housing and at which articles to be wrapped are guided past and required folds are produced one after the other, means for the transfer of partially wrapped articles to the packing rotor, equipment associated with the packing rotor for the production of a rotary wrap, wherein external outlines of the retaining element pairs of the gripper rot or form a matrix around which the wrappers are folded, the folding operations are divided between at least one folding station associated with the gripper rotor and at least one folding station associated with the packing rotor, and means are provided for the guidance of the retaining element pairs of the two rotors in detent positions relative to each other in radial and in tangential relationship for the folding operations and for the transfer.

Preferably, folding elements for insertion of end folds and side folds are associated with the gripper rotor and the folding elements for insertion of base folds and final folds are associated with the packing rotor. Expediently, the end folds are produced by a fork-shaped end face folder surrounding the matrix. The retaining element pairs of the rotors are preferably guided along cam discs, with foot points or fulcra of the retaining element pairs of the gripper rotor being guided on a circular path and foot points or fulcra of the retaining element pairs of the packing rotor being guided on the path of an epicycloid. The epicycloid path can be produced by toothed wheels, at which the foot points of the retaining element pairs of the two rotors-are eccentrically mounted, rolling along a central wheel of fixed location.

Apparatus embodying the invention may have the advantage that already formed folds are covered over so as to be retained by subsequent folds. Thus, a secure folding may be possible even for elastic materials. The distribution 6f the folding operations over several folding stations and matching of the peripheral speeds of the retaining element pairs to each other during folding results in a favourable kinematic system with low loading of gears. Folding can be carried out by way of retaining cheeks which act as a matrix so that deviations in shape of the articles to be wrapped do not play any role and the wrapper quality has no significant influence.

It is also advantageous that the re-equipment to rotary folding may be extremely simple by contrast to the state of the art.

Folding elements for folding to produce small bags can be removed and the rotary head, which is present in any case, is then put into operation.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which:

Fig. 1 is a schematic view of part of folding apparatus embodying the invention, are detail views showing gripper elements and folding elements of the apparatus and different stages in production of folds; and is a diagram showing different positions of a basefolder of the apparatus.

Referring now to the drawings there is show folding apparatus for folding wrappers around articles, in this particular example sweets 20. The apparatus comprises a gripper rotor 1 and a packing rotor 10 arranged one beside the other. The rotors 1 and 10 execute continuous and mutually opposite rotary movements as indicated by arrows in Fig. 1. Retaining tongs 2 and retaining cheeks 11, which are arranged in pairs, for the retention of the sweets 20, are disposed uniformly distributed over the circumferences of the rotors 1 and 10. Various processing stations with folding elements and stations for reception, transfer and ejection are arranged along the path of movement of the retaining tongs 2 and the retaining cheeks 11.

Figs. 2A to E Fig. 3 The apparatus includes various operating elements, for example, clamping tongs 6 which are moved along with and articulated at the gripper rotor 1, base folders 13 and inward folders 14 which are articulated to the apparatus frame, and side folders 7 and end face folders 9 which are articulated to the frame and guided parallel to the retaining tongs along a coupling cam.

The retaining tong pairs 2 and the retaining cheek pairs 11 execute movements relative to the continuously rotating rotors 1 and 10 respectively carrying them. For this purpose, the retaining tong pairs and the retaining cheek pairs have the form of rockers with follower rollers guided by cam discs 16 and 18. The fulcra or foot points 3 of the rockers of the retaining tong pairs 2 are so mounted on the gripper rotor 1 as to follow a circular path on rotation of the rotor. The fulcra or foot points 12 of the rockers of the is retaining cheek pairs 11 are eccentrically mounted on toothed wheels 23 which are rotatably mounted on the packing rotor 10 and and run along the circumference of a central wheel 12 of fixed location, whereby the fulcra 12 follow an epicycloid path 17. Since the fulcra 3 follow a circular path and the fulcra 12 the path of an epicycloid 17, additional tangential and radial courses of movement, with detent positions referred to the setting of the retaining tongs 2 and of the retaining cheeks 11 relative to each other, are imparted to the retaining tongs 2 and the retaining cheeks 11 during the continuous rotation of the rotors 1 and 10. On the one hand, these positions of the retaining tongs 2 or the retaining cheeks 11 are utilised in the processing and transfer stations for prolongation of the handling time and, on the other hand, the relative movement is used for matching the movements of the folding elements.

In operation, each sweet 20 is seized by a pair of the retaining tongs 2 in the gripper rotor 1. As is evident from Fig. 2A, the external outlines of the retaining tongs 2 are shaped so that they serve as a matrix for the folds and thus exact and straight folding edges can be achieved independently of the shape of the sweet. A horn 21 is arranged as a folding edge at the opening retaining tongs 21. - A wrapper 4 is applied over the sweet 20 already held by the retaining tongs 2, and revolving clamping tongue 6.

As shown in Fig. 2B, a supporting edge 19 follows behind and stabilises the wrapper 4 in this position. The rotary path of the retaining tongs 2 with the sweet 20 and the wrapper 4 is tangent to a preliminary folding element 7, while the wrapper 4 is folded over the external outline, acting as a matrix,. of the retaining tongues 2.

Referring to Fig. 2C, double folds - fold c - are then pressed in at the end face around the fixed edges of the tongs 2 with the aid of a U-shaped end face folder 9. The block 5 has a supporting effect at the inward side of the wrapper 4 for the formation of the fold edges.

A side folder 8 turns over the free end of the wrapper 4 and clamps it firmly against the tongs 2. Subsequently, the end face folder 9 runs out of the path and the clamping tongue 6 releases without the folder wrapper 4 changing in position or springing open.

k between a revolving block 5 1 As indicated in Fig. 20, the retaining tongs 2 now pivot forward relative to the gripper rotor 1 due to the action of the cam disc 16 and the wrapper 4 is detached from the block 5. At the same time, the retaining cheeks 11 pivot forward relative to the packing rotor 10 due to the action of the cam disc 18 and the path of the fulcrum 12 so that the clamping tongs 2 and the retaining cheeks 11 move into each other tangentially and radially. The side folder 8 detaches from the retaining tongs 2 and frees the wrapper 4. In that case, the sweet with the wrapper applied thereto is taken over by the retaining cheeks 11.

In a following folding station as shown in Fig. 2E, the end side is laid below the base-fold-d - and retained by a rotating base folding element 13 until this fold is covered by a side part - fold e - folded by an inner folding element 14.

Three positions of the base folding element 13 are illustrated in Fig. 3. In position L1, the base fold is drawn in by the wide side of the element 13. The folding is executed in position L2, while in position D the fold is still fixed by the narrow side of the element 13, whilst the element 14 at the same time has room to fold the side apart.

On further rotation of the packing rotor 10, the final fold is formed in known manner by moving against a stationary folding ring 15.

A wrapper roll forms on the opposite packing side during the afore-mentioned folding sequences and is closed in the subsequent rotary folding station. In this station, the retaining cheeks are held in a detent position by the afore-described means, the cooperation of the fulcra 12 of the retaining cheeks 11, the path of the epicycloid 17 and the cam disc 18.

The execution of the final folding and the rotary folding are generally known and not illustrated in the drawings.

Claims

Folding apparatus for folding wrappers around articles, comprising a gripper rotor and a packing rotor each provided with retaining element pairs for retaining such articles, the external outline of each retaining element pair of the gripper rotor forming a matrix for folding of wrappers therearound, at least one folding station which is associated with the gripper rotor and disposed in a fixed location in the apparatus and at which each article retained by a gripper element pair of the gripper rotor is partially wrapped in a wrapper by folding of the wrapper, means to cause each partially wrapped article to be transferred from the respective retaining element pair of the-gripper rotor to a gripper element pair of the packing rotor by relative radial and rotational displacement of the pairs into positions for mutual co-operation, and at least one further folding station which is associated with the packing rotor and disposed in a fixed location in the apparatus and at which each article retained by a gripper element pair of the packing rotor is fully or more fully wrapped in the respective wrapper by further folding of the wrapper.
2. Apparatus as claimed in claim 1, wherein said station or stations associated with the gripper rotor comprise means for producing end folds and side folds in the wrappers and said station or stations associated with the packing rotor comprise means for producing base folds and final folds in the wrappers.
3. Apparatus as claimed in claim 2, said means for producing end folds comprising a forked element engageable around the matrix formed by each retaining element pair of the gripper rotor.
4. Apparatus as claimed in any one of the preceding claims:, said means for causing transfer of articles comprising cam means to pivot the retaining elements, the fulcra of the retaining element pairs of the gripper rotor being guided on a circular path and the fulcra of the retaining element pairs of the packing rotor being guided on an epicycloid path.
5. Apparatus as claimed in claim 4, wherein the gripper element pairs of the packing rotor are mounted at their fulcra on gearwheels eccentrically of the axes thereof, the gearwheels being arranged to roll around the circumference of a central wheel of fixed location.
6. Apparatus substantially as hereinbefore described with reference to the accompanying drawings.