GB1562347A - Wrapping machinery - Google Patents

Description

(54) IMPROVEMENTS IN WRAPPING MACHINERY (71) We, BAKER PERKINS HOLDINGS LIMITED, of Westfield Road, Peterborough, PE3 6TA, a British Company, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to wrapping machines of the type, herein termed the type specified, comprising a tube former adapted to form a continuously travelling web of wrapping material into a tube, means for feeding articles in spaced relationship to the tube former so that they become entubed in the tube of wrapping material and rotary sealing heads disposed beyond the tube former and operative to form transverse seals in the tube of wrapping material between the entubed articles.

In wrapping machines of this type the sealing heads may also operate to sever the tube of wrapping material into individual packages at the transverse seals. When, as is generally the case, the wrapping material is heat sealable the sealing heads are usually heated so that they provide both heat and pressure to seal the tube.

Machines of this type are, of course, capable of producing packages containing either a single article or a batch of articles.

Existing machines form heat seals between consecutive packages which are permanent in that the seals cannot be re-established by the user of the packages once they have been opened. It is often desirable that a package containing a batch of articles should be capable of being reclosed whenever one or more of the articles have been removed therefrom by a consumer.

The object of the invention is to provide a machine of the above type which is readily convertible from operation to produce packages with seals at both ends to packages having a seal at one end only. the other end being open. Such conversion is desirable, for example, in the case of a machine for use in a bakery and required sometimes to produce packages each containing a single long product and at other times to produce packages containing a number of shorter products all of which may not be eaten on a single occasion.

The invention accordingly provides a wrapping machine of the above specified type, wherein each sealing head carries two circumferentially spaced sealing jaws which are cooperable in pairs to form respectively, as they pass through a sealing zone, a transverse seal at the trailing end of one package and a transverse seal at the leading end of the next following package, said sealing heads being relatively adjustable to alternative configurations, in one of which both pairs of sealing jaws are operative to produce packages transversely sealed at both ends and in the other of which one pair only of sealing jaws is operative to form packages transversely sealed at one end only.

Preferably one sealing head carries a knife disposed between its two sealing jaws and the other sealing head carries an anvil disposed between its two sealing jaws, the knife and the anvil cooperating to sever the tube into individual packages in each configuration of the sealing heads.

When the machine is adjusted to produce packages transversely sealed at one end only, the open end of each package may be closed by forming a neck beyond the article or articles contained in the package, e.g. by twisting or bunching, and securing the closure so formed by passing a wire around the neck and nipping the neck by twisting the wire, or by securing the twist by a clip. Such final closure of the package may be effected by hand, or the open-ended packages may be delivered to a well-known type of bag closing machine.

One embodiment of the invention will now be described with reference to the accompanying diagrammatic drawings, in which: Figure 1 illustrates a typical wrapping machine according to the invention, Figure 2 illustrates one type of package formed on the machine illustrated in Figure 1, Figure 3 illustrates an alternative type of package, Figure 4 is an elevation showing the sealing heads in more detail, Figure 5 is a section on the line 5-5 in Figure 4, Figure 6 is a section on the line 6-6 in Figure 4, and Figures 7, 8 and 9 are explanatory diagrams.

As shown in Figure 1, articles 10 to be wrapped are advanced by the flights 11 of an infeed conveyor 12 to a tube former 13, to which a web 14 of heat-sealable wrapping material is fed from a reel (not shown).

The tube former 13 forms the web 14 into a tube 16 surrounding the articles and having a longitudinal seal 15 formed by driven sealing rollers, one of which is shown at 17, which feed the wrapping material through the machine. Transverse seals are formed in the tube between the articles by upper and lower rotary sealing and severing heads 18 and 19.

The lower head 19 (Fig. 4) includes a shaft 21 rotatably mounted in the framework 22 of the machine and carrying, see also Fig. 7, leading and trailing heated sealing jaws 24 and 26, respectively, between which is secured an anvil 27. The shaft 21 also carries a pair of spaced flanges 28 adjacent to each of which is secured a cam disc 29, each having a cut-away portion 31 (Fig. 5).

The upper head 18 includes a shaft 33, carrying a pair of spaced flanges 35, and also (see Fig. 7) leading and trailing heated sealing jaws 36 and 37, respectively, between which is secured a knife 38.

Slidably mounted on the shaft 33 adjacent each flange 35 is a cylindrical disc 39 capable of being secured on the shaft 33 either adjacent the flanges 35 as shown in full lines in Fig. 4, in which position it is in alignment with a corresponding cam disc 29 on the lower head, or in the position shown in chain-dotted lines in Figure 4, i.e. out of alignment with the disc 29. The cam discs 39 are keyed to the shaft 33 by keys 40 and are secured to the shaft in their alternative positions by grub screws 41.

The shaft 33 is rotatably mounted in arms 42 (Fig. 6) pivoted at 43 to the framework 22. Springs 44, interposed between lugs 45 on the arms and studs 46 screwed into the framework 22, urge the upper sealing jaws 36 and 37 and the knife 38 towards the lower sealing jaws 24 and 26 and the anvil 27 as they move into contact to form the transverse seals 50 (Fig. 2) and to cut the tube 16 between these seals into individual packages. The upper and lower shafts 33 and 21 are interconnected by gears 47, 48 and the lower shaft 21 is driven continuously by a chain and sprocket drive 49 to impart continuous rotary motion to the shafts 33 and 21.

When it is desired that the machine should produce packages having transverse seals 50 at both ends, as shown in Fig. 2, the discs 39 on the upper shaft 33 are moved out of alignment with the cam discs 29 on the lower shaft 21, i.e. to the position shown in chain-dotted lines in Fig. 4. As the shafts 21 and 33 rotate, the tube 16 of wrapping material is flattened and heat-sealed by both sets of jaws 24, 36 and 26, 37 on the upper and lower heads to form two transverse seals 50, the tube being severed between the seals by coaction of the knife 38 with the anvil 27, as shown in Fig. 8, to form the individual packages, one having a seal 50 at its trailing end and being followed by another having a seal 50 at its leading end.

When, however, it is desired that the machine should produce packages having a transverse seal 50 at one end only, as shown in Fig. 3, the discs 39 are displaced on the shaft 33 to positions adjacent the flanges 35 so that the discs 39 engage the cam discs 29.

As the leading jaws 24 and 36 approach the sealing position, the cam discs 29 raise the discs 39 to cause the upper shaft 33 to be lifted away from the lower shaft 21 so that the jaw 36 is raised out of contact with the jaw 24 (see Fig. 7), and consequently no sealing action takes place, which leaves the trailing portion of the package leaving the sealing zone unsealed to produce a filled open-ended package. Continued rotation of the shaft 21 brings the cut-away portions 31 of the cam discs 29 into the sealing zone, thus allowing the upper shaft 33 to move down to bring the knife 38 into engagement with the anvil 27, as shown in Fig. 8, thus severing the tube of wrapping material.

During continued rotation of the shafts 21 and 33 the trailing jaw 37 moves into engagement with the trailing jaw 26, as shown in Fig. 8, to effect a transverse seal 50 in the tube of wrapping material at the leading end of the succeeding package. As the shafts 21 and 33 continue their rotary movement the cut-away portions 31 move clear of the sealing zone and the cam discs 29 lift the shaft 33 away from the shaft 21.

Accordingly when the discs 29 and 39 are in alignment packages will be produced having one end sealed and the other end left unsealed.

Such open-ended packages are transferred in succession to a known bag closing machine which forms a neck above the level of the articles, by bunching the open upstanding portion of the tube, and secures the closure by passing a wire 51 around the neck and nipping the neck by twisting the wire as indicated in Fig. 3.

When a change from the production of one type of package to the other is required, it is a simple matter for an operator to move the discs 39 either into operative position to produce open-ended packages, or into inoperative position to produce packages with seals at both ends.

Fig. 2 shows a case in which each package contains a single article 10. Fig. 3 shows a case in which each package contains two rows of shorter articles 10.

WHAT WE CLAIM IS: 1. A wrapping machine of the type specified, wherein each sealing head carries two circumferentially spaced sealing jaws which are cooperable in pairs to form respectively, as they pass though a sealing zone, a transverse seal at the trailing end of one package and a transverse seal at the leading end of the next following package.

said sealing heads being relatively adjustable to alternative configurations, in one of which both pairs of sealing jaws are operative to produce packages transversely sealed at both ends and in the other of which one pair of sealing jaws is operative to form packages transversely sealed at one end only.

2. A wrapping machine according to claim 1, wherein one sealing head carries a knife disposed between its two sealing jaws and the other sealing head carries an anvil disposed between its two sealing jaws, the knife and the anvil co-operating to sever the tube into individual packages in each configuration of the sealing heads.

3. A wrapping machine according to claim 1 or claim 2, which includes means operative in said other configuration of the sealing heads to displace one sealing head, during each revolution thereof, in relation to the other sealing head while one pair of jaws is passing through the sealing zone.

4. A wrapping machine according to claim 1 or claim 2, wherein each sealing head includes a shaft carrying a disc which rotates with the shaft, the disc on one shaft being adjustable on the shaft to alternative positions in which it is respectively aligned with the disc on the other shaft and out of alignment with said other disc, one of said discs being a cam disc which cooperates with the other disc to separate the sealing heads during passage of one pair of sealing jaws through the sealing zone.

5. A wrapping machine according to claim 4, which includes means for urging the sealing heads resiliently towards one another.

6. A wrapping machine according to claim 1, substantially as described herein with reference to the accompanying drawings.

Dated this 31st day of January 1978.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. machine which forms a neck above the level of the articles, by bunching the open upstanding portion of the tube, and secures the closure by passing a wire 51 around the neck and nipping the neck by twisting the wire as indicated in Fig. 3. When a change from the production of one type of package to the other is required, it is a simple matter for an operator to move the discs 39 either into operative position to produce open-ended packages, or into inoperative position to produce packages with seals at both ends. Fig. 2 shows a case in which each package contains a single article 10. Fig. 3 shows a case in which each package contains two rows of shorter articles 10. WHAT WE CLAIM IS:

1. A wrapping machine of the type specified, wherein each sealing head carries two circumferentially spaced sealing jaws which are cooperable in pairs to form respectively, as they pass though a sealing zone, a transverse seal at the trailing end of one package and a transverse seal at the leading end of the next following package.

said sealing heads being relatively adjustable to alternative configurations, in one of which both pairs of sealing jaws are operative to produce packages transversely sealed at both ends and in the other of which one pair of sealing jaws is operative to form packages transversely sealed at one end only.

2. A wrapping machine according to claim 1, wherein one sealing head carries a knife disposed between its two sealing jaws and the other sealing head carries an anvil disposed between its two sealing jaws, the knife and the anvil co-operating to sever the tube into individual packages in each configuration of the sealing heads.

3. A wrapping machine according to claim 1 or claim 2, which includes means operative in said other configuration of the sealing heads to displace one sealing head, during each revolution thereof, in relation to the other sealing head while one pair of jaws is passing through the sealing zone.

4. A wrapping machine according to claim 1 or claim 2, wherein each sealing head includes a shaft carrying a disc which rotates with the shaft, the disc on one shaft being adjustable on the shaft to alternative positions in which it is respectively aligned with the disc on the other shaft and out of alignment with said other disc, one of said discs being a cam disc which cooperates with the other disc to separate the sealing heads during passage of one pair of sealing jaws through the sealing zone.

5. A wrapping machine according to claim 4, which includes means for urging the sealing heads resiliently towards one another.

6. A wrapping machine according to claim 1, substantially as described herein with reference to the accompanying drawings.

Dated this 31st day of January 1978.