GB2360718A

GB2360718A - Device for depositing an adhesive on a web of material

Info

Publication number: GB2360718A
Application number: GB0105862A
Authority: GB
Inventors: Willi Krieger
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2000-03-11
Filing date: 2001-03-09
Publication date: 2001-10-03
Anticipated expiration: 2021-03-09
Also published as: CH694528A5; DE10011935A1; GB2360718B; GB0105862D0; DE10011935C2; ITMI20010454A1

Abstract

A device 10 for depositing an adhesive on a web of material 1 is disposed before a severing arrangement 20 which severs, from the said web of material 1 individual blanks 3 which serve to form packaging containers. The web of material 1 is conveyed in a timed cycle by means of a conveyer arrangement constructed as a suction belt 11. The device (10) for depositing the adhesive has an arrangement 25 for applying the said adhesive, which arrangement comprises an adhesive-dispensing strip 26. Provision is made, according to the invention, for the adhesive-dispensing strip 26 to be displaceably disposed in such a way that the said strip can be brought up in the direction of the severing arrangement 20 after a machine stoppage or the like. As a result of this, it is possible to continue to use, at least in some cases, blanks 3 onto which the adhesive already deposited has dried.

Description

2360718 Device for deDoqiting an adhesive on a web of m2terial

Prior art

The invention relates to a device for depositing an adhesive on a web of material, in accordance with the pre-characterising clause of claim 1. A device of this type is a component part of a packaging machine for manufacturing packaging containers having overlapping seams and folded bottoms. For this purpose, s adhesive is applied at regular intervals, in the region of the future longitudinal seams and future bottoms, to a web of material which is conveyed in a timed cycle. In the prior art, this takes place by means of a stationary applying arrangement for the adhesive, which arrangement is located, for mechanical engineering reasons, a few blanks' lengths, as a rule between three and five blanks' lengths, before the arrangement for severing the blanks from the web of material. Under these circumstances, the adhesive is deposited, in each case, during the phase involving the advancing of the web of material, the sticking pattern being brought about by means of adhesive- dispensing nozzles which are disposed side by side and transversely to the web of material and which can be is activated by valves. In order, in the event of a machine stoppage or the like, to prevent the blanks with dried-on adhesive which are located between the arrangement for applying the adhesive and the severing arrangement from having to be removed in a costly manner, it is known practice, from DE 40 20 935 C2, to reactivate the dried-on adhesive by means of heat. For this purpose, heatable forming mandrels or pressure plates on a so-called "mandrel-wheel machine" incorporated downstream are required, which thus increase expenditure on the packaging machine from the device-engineering point of view and which may possibly not work satisfactorily with all types of adhesive and all sticking patterns.

- 2 Advantages of the invention By contrast with the above, the device according to the invention with the characterising features of claim 1, for depositing an adhesive on a web of material, has the advantage that it needs no heatable elements and can be used for all types of adhesive, and yet permits access to the individual components of the packaging machine in the region of the severing arrangement. This is achieved lo through the fact that the arrangement for applying the adhesive, which arrangement can be moved in the longitudinal direction of the web of material, works a few blanks' lengths before the severing arrangement during normal operation, and accessibility is thus provided in the region of the said severing arrangement. Only in the event of machine stoppages or the like is the is arrangement for applying the adhesive conveyed to a point in front of the severing arrangement, so that adhesive can be deposited again on this region of the web of material. As a result of this, the blanks which have already been provided with adhesive can continue to be used, at least in some cases. If, in spite of this, removal or extraction of blanks of packing material should still be necessary, this is made easier by the reduced number of blanks to be extracted.

Other advantageous fluther developments of the device according to the invention are indicated in the subclaims.

Drawing An exemplified embodiment of the invention is represented in the drawing and will be explained in greater detail below. The single diagram shows, in a simplified side view, a device according to the invention for depositing an adhesive on a web of material.

Description of the exemplified embodiment

The device 10 represented in the diagram is part of a so-called "packing planC which forms bag-shaped packaging containers from blanks 3 cut to length from an lo endless web of material 1, preferably consisting of paper, and fills them with a filling such as flour or sugar. The device 10 has an arrangement for conveying the web of material 1, which arrangement works in a timed cycle and is in the form of a suction conveyer belt 11 on the upper strand 12 of which the web of material 1 lies as a result of being attached by suction. The suction conveyer belt is 11 is connected, by means of a belt transmission 13, to a drive 14 which is preferably constructed as a servomotor. Disposed in the prolongation of the strand 12, in front of and behind the latter viewed in the direction of conveyance 16 of the web of material 1, are sheet- metal supports 17, 18 which adjoin the said strand 12 almost without any intervening space, and which construct, in conjunction with the said strand 12, a flat supporting face for the web of material 1. Whereas the sheet-metal support 17 facing towards the storage roll 2 of the web of material 1 is relatively long, the sheet- metal support 18 has only a relatively small length. Disposed at the end of the sheet-metal support 18 is a severing arrangement 20 with two cutting knives 21, 22, which can be conveyed towards one another,- for severing one blank 3 at a time, of length a, from the web of material 1. The said blanks 3 are fed, by a means which is not represented, to a so-called "mandrel-wheel machine" which is incorporated downstream of the device 10 and which folds one blank 3 at a time round a forming mandrel 23 and thus forms the packaging container. From the mandrel-wheel machine, the packaging containers are then fed to a filling arrangement.

Before the forming of the packaging containers, the blanks 3 are provided, before 5 their severance from the web of material 1, with wet glue by means of the device 10 in the zones of the future longitudinal seams and future bottoms. This purpose is served by an arrangement 25 for applying the wet glue or adhesive, which arrangement is substantially disposed in the region of the suction conveyer belt 11 and of the sheet-metal support 17.

The applying arrangement 25 has an adhesive-dispensing strip 26 extending transversely across the web of material 1 and having adhesive-dispensing nozzles 27 which are disposed side by side and can be activated individually via valves in order to be able to apply the required sticking pattern over the breadth of the web of material 1. The way in which an adhesive-dispensing strip 26 of this type functions is known per se and will therefore not be explained in any greater detail below, since it is not essential to the invention. The adhesive-dispensing strip 26 is fastened on a carrier 27 which is connected to a shaft 28 in a torsion-proof manner. The shaft 28, and therefore the adhesive-dispensing strip 26, can be pivoted by means of a pneumatic cylinder 29 which is supported on a frame part 31 connected to the carrier 27.

When the adhesive-dispensing strip 26 is in the lowered position represented in the diagram, the adhesive-dispensing nozzles 27 for applying or dispensing the 2 5 adhesive are in operative connection with the web of material 1, whereas the said adhesive-dispensing nozzles 27 are at a distinct distance from the web of material 1 when the adhesive-dispensing strip 26 is in the raised position.

What is essential to the invention is the disposition of the carrier 27, in a manner longitudinally displaceable in the direction of the web of material 1, on at least one guide bar 32 which extends at a uniform distance above the suction conveyer belt 11 and the sheet-metal supports 17, 18. The guide bar 32 is connected to the s frame of the device 10 in a stationary manner via a bracket 33 and has a length such that the adhesive-dispensing strip 26 can be displaced over the length of a number of future blanks 3, preferably three, which are disposed immediately before the severing arrangement 20. In the most favourable case, the adhesivedispensing strip 26 reaches, with its adhesive-dispensing nozzles 27, right up to the cutting knives 21, 22 of the severing arrangement 20. Often, however this is not possible for mechanical engineering reasons. Also represented in the diagram, therefore, is the case in which the adhesive-dispensing strip 26 is able to overlap only part of the future blank 3 located immediately before the severing arrangement 20, that is to say the said strip does not reach as far as the cutting knives 21, 22 (that position of the applying arrangement 25 which is drawn in in broken lines). The drive which brings about the longitudinal displacement of the adhesive-dispensing strip 26 and of which no further details are represented, is preferably constructed as a linear drive.

The device 10 works in the following manner: During normal operation of the device 10, the adhesive-dispensing strip 26 is disposed, as shown in the diagram, in the region of the third future blank 3 before the severing device 20. At the same time, the web of material 1 is drawn forward under the adhesive-dispensing strip 26 in a timed cycle by means of the suction conveyer belt 11. For the purpose of applying the required sticking pattern, the adhesive- dispensing nozzles 27 are activated via a valve-control system during the advance of the web of material 1. During normal operation, the possibility of gaining access to the region of the severing arrangement 20 is thus ensured by the applying arrangement 25 or adhesive-dispensing strip 26, which is at a distance from the said severing arrangement 20.

If a machine stoppage or the like occurs, in which the suction conveyer belt 11 no s longer conveys the web of material 1 onwards, the adhesive already deposited on the web of material 1 in the region between the adhesive- dispensing strip 26 and the severing arrangement 20, dries on. In order to prevent these blanks 3, which will subsequently be severed from the web 1 of material, from having to be removed in a costly manner, and in order to enable them to continue to be used, at lo least in some cases, the adhesive-dispensing strip 26 is conveyed, when the packaging machine or the device 10 is restarted, into its end position (drawn in in broken lines) facing towards the severing arrangement 20.

In the case represented in the exemplified embodiment, in which the adhesive- is dispensing strip 26 cannot be conveyed quite as far as the severing arrangement 20, and therefore as far as that end of the corresponding future blank 3 which faces towards the said severing arrangement 20, there are two possibilities: In the first, preferred case, the suction conveyer belt 11 is conveyed back slightly, against the normal direction of conveyance 16, with the adhesive-dispensing strip 26 raised, so that that end of the future blank 3 or of the web of material 1 which faces towards the severing arrangement 20 is located underneath the said adhesive-dispensing strip 26. The adhesive-dispensing strip 26 is then lowered and the end of the future blank 3, or of the web of material 1, is moved in the direction of the severing arrangement 20 again, up to the latter. When this has taken place, the adhesive-dispensing strip 26 is conveyed back as far as its normal operating position, that is to say as far as the end of that end of the third future blank 3 before the severing arrangement 20 which faces away from the said severing arrangement 20. Under these circumstances, adhesive is applied via the 7 adhesive-dispensing nozzles 27, both during the (short) advance of the suction conveyer belt 11 in the direction of conveyance 16 and also during the return stroke of the adhesive-dispensing strip 26 into its normal position, to that section of the web of material which is already provided with dried-on adhesive. As soon s as the adhesive-dispensing strip 26 is located in its normal operating position, the suction conveyer belt 11 and the severing arrangement 20 resume their normal operation.

In the case which has just been described, in which the adhesivedispensing strip lo 26 cannot be conveyed right up to the severing arrangement 20 and the suction conveyer belt 11 is initially operated, to some extent, oppositely to the direction of conveyance 16, it is of advantage if the web of material 1 has a buffer store which absorbs that section of the said web of material which is conveyed backwards, without the formation of folds or the like occurring.

is In the event of the adhesive-dispensing strip 26 not being capable of being conveyed up to the severing arrangement 20, and of the suction conveyer belt 11 not being moved oppositely to the direction of conveyance 16, the first future blank 3 which faces towards the severing arrangement 20 is not provided, or is only insufficiently provided, with new adhesive. In this event, the said blank 3, or the packaging container formed therefrom on the forming mandrel 23, must be removed. However, the other two future blanks 3 between the severing arrangement 20 and the adhesive-dispensing strip 26 which is located in the normal position, can be used after the fresh application of adhesive.

In the most favourable case, in which it is possible, for mechanical engineering reasons, to convey the adhesive-dispensing strip 26 right up to the severing arrangement 20 or to the corresponding end of the web of material 1, it is not 8 necessary to move the suction conveyer belt 11 back. In this case, adhesive is deposited afresh, by means of the adhesive-dispensing strip 26, on all three future blanks 3 located between the severing arrangement 20 and, as regards its normal position, the adhesive-dispensing strip 26, before the latter passes out of its s normal operating position and into normal operation again, during the moving of the web of material 1 in a timed cycle by means of the suction conveyer belt 11.

From what has been described above, it can be seen that it is possible, through the longitudinal displaceability of the adhesive-dispensing strip 26 in the direction of lo the severing arrangement 20, to reduce the number of blanks 3 to be removed after a machine stoppage or the like, at least by comparison with an adhesivedispensing strip 26 which is not longitudinally displaceable, or in the most favourable case, to continue to use all the blanks 3.

is The device 10 described above can be modified in multifarious ways without deviating from the concept of the invention. Thus for example, it is conceivably possible to use another conveyer means for the web of material 1, instead of the suction conveyer belt 11. The longitudinally displaceable disposition of the adhesive-dispensing strip 26 on the guide bar 32 may also be modified as a result 2 0 of a different construction.

9

Claims

1. Device (10) for depositing an adhesive on a web of material (1), the said device having: an arrangement (11), which works in a timed cycle, for conveying the web of material (1); an arrangement (20) for severing blanks of packing material (3) from the said web of material (1) which is conveyed in a timed cycle; and an arrangement (25), which is a few blanks' lengths distant from the said severing arrangement (20) during normal operation, for applying the adhesive, characterised in that, after a machine stoppage or the like, the arrangement (25) for applying the adhesive can be moved in the direction of the arrangement (20) for severing blanks of packing material (3), for the fresh application of adhesive lo in the direction of conveyance (16) of the web of material (1).

2. Device according to claim 1, characterised in that the arrangement (25) for applying the adhesive has an adhesive-dispensing strip (26) which is displaceably disposed on a stationary bar (32).

is

3. Device according to claim 2, characterised in that, in the region of the bar (32), the web of material (1) rests on a flat support face on the arrangement, which is constructed as a suction belt (11), for conveying the web of material (1), and that, in the region of the bar (32), the said web of material (1) is at a constant distance 2 0 from the adhesivedispensing strip (26).

4. Device according to claim 2 or 3, characterised in that the adhesivedispensing strip (26) can be pivoted away from the web of material (1).

5. Device according to one of claims 2 to 4, characterised in that the displacement stroke of the adhesive-dispensing strip (26) on the bar (32) amounts to three future blanks of packing material (3) which are disposed immediately before the severing arrangement (20).

6. Device according to one of claims 2 to 5, characterised in that the adhesivedispensing strip (26) extends transversely to the web of material (1) and comprises a number of adhesive-dispensing nozzles (27) which can be activated by valves.

7. Device according to one of claims 3 to 6, characterised in that sheetmetal supports (17, 18) for the web of material (1) which adjoin the suction conveyer belt (11) almost without any intervening space, are disposed in front of and behind the said suction conveyer belt (11), viewed in the direction of conveyance rs (16) of the said web of material (1).

8. Device according to one of claims 1 to 7, characterised in that the adhesive is deposited on the web of material (1) in the region of future longitudinal seams and bottoms, and that the blanks of packing material (3) serve to form packaging 2 0 containers.

9. Device substantially as described herein with respect to the accompanying drawing.