BAG SEALING APPARATUS

Description

[0001] The invention relates to bag sealing apparatus.

[0002] It is known to produce air bags, or air pillows, for use in packaging goods to protect them. Thus, a delicate article might be surrounded with air pillows in a cardboard box to protect it from damage during transport. It is known to make such air pillows from heat sealable plastics material and the bags are produced in a strip with each bag being heat sealed from the next. The known sealing method is unreliable however as the back pressure from air in the bag as it is being sealed tends to unseal the bag.

[0003] According to the invention there is provided apparatus for making a bag of gas for protective packaging comprising a source of compressed gas, a compressed gas supply pipe and two rollers arranged side by side and between which material for making a bag passes, one or both of the rollers including a circumferential recess and the recess or both recesses together receiving the supply pipe.

[0004] In this way the amount of fluid entering the bag can be precisely controlled as backflow past the rollers is limited. Preferably the supply pipe substantially fills the recess or both recesses. The bag material may be provided as a strip. Preferably bag sealing means is provided immediately past the rollers. Thus, the bag sealing will leave only a minimal amount of fluid between the seal and the rollers. Preferably clamping means is provided for clamping a bag downstream of the sealing means to reduce fluid back pressure.

[0005] In this way, as the bag is clamped downstream of the sealing means, the back pressure does not operate on the seal and a good seal can be reliably ensured. Also the quantity of fluid introduced into the bag can be closely controlled as fluid cannot escape past the clamping means during sealing.

[0006] The fluid source may be a source of compressed gas, preferably compressed air.

[0007] The sealing means may seal the bag in any suitable way, such as by adhesive or mechanical means, but preferably the sealing means comprises heat sealing means.

[0008] The clamping means may comprise a resilient member which is urged against the bag. The resiliency aids in providing a fluid tight seal. Preferably, the clamping means comprises two resilient clamping members arranged on opposite sides to clamp a bag between them.

[0009] Preferably, the clamping means is arranged to clamp the bag before the sealing means starts to seal the bag.

[0010] The clamping means and sealing means may be mounted separately, but in one embodiment, a clamping member of the clamping means and a sealing member of the sealing means are mounted together on a mounting member. Preferably, on the mounting member, the clamping member is resiliently mounted ahead of the sealing member so as to engage the bag before the sealing member. This ensures that the bag is clamped before the sealing operation commences. Preferably, a second mounting member is provided which mounts a second clamping member and/or a second sealing member. Conveniently, only one of the first and second mounting members is movable, but in another embodiment both of the first and second mounting members may be movable towards and away from each other. The or each mounting member is preferably moved pneumatically.

[0011] The apparatus may be arranged to operate in a cycle. The material for the bag may be provided as a strip which is advanced by advancing means through the apparatus.

[0012] The means for advancing the bag material may take any suitable form and preferably comprises two rollers side by side between which the material passes.

[0013] The bag material may be in the form of two layers open at one side and the gas supply pipe may extend between the layers through the open side. Means is preferably provided for sealing the open side.

[0014] This arrangement allows the bag to be filled directly and without complication.

[0015] The material may be open at both sides but preferably is open on only one side. The open side of the material is preferably sealed upstream of the end of the supply pipe. The side sealing means may take any suitable form and may comprise heat sealing means. The side sealing means preferably comprises a member which is movable towards and away from the side of the material. The apparatus preferably includes bag sealing means for sealing the bag after the bag has been filled from the supply pipe. The bag sealing means preferably lies downstream of the advancing means. The bag sealing means preferably includes a member which is movable towards and away from the material. The bag sealing means and the side sealing means are preferably rigidly connected and moved together. The bag sealing means member and/or the side sealing means member may be moved by pneumatic means.

[0016] The means for advancing the bag material may take any suitable form and preferably comprises two rollers side by side between which the material passes.

[0017] Two embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of the apparatus of the first embodiment;

Fig. 2 is a detail side elevation of the heat sealing part of the apparatus of Fig. 1; and,

Fig. 3 is the view of Fig. 2 of the second embodiment.

[0018] Fig. 1 shows the apparatus 10 of the first embodiment. A roll of bag material 12 is stored on a spindle and material 14 from the roll passes over an upper roller 16 and downwardly between two advancing rollers 18 which grip the material and are driven by a motor (not shown) to advance the material in steps. The material is in two layers with a fold on one side and being open at the other side.

[0019] A pneumatic source powers two pistons 20 provided beneath the advancing rollers 18. At the inner end of each piston 20 is connected a bag sealing member 22 parallel to and beneath one of the advancing rollers 18. The outer end of each piston 20 is connected to an arm 24 which extends upwardly past the advancing rollers 18 and inwardly to mount an upright side member 26. One side member 26 includes a heating element 28 and the other side member 26 mounts a sprung mounted part 30. A compressed air supply, pipe 32 extends inwardly parallel to the advancing rollers 18 so as to 11e between two layers of the material 14 centrally thereof and turns to extend downwardly past the upright members 26 to the advancing rollers 18. Each advancing roller 18 includes a central circumferential recess 34 such that the material and the end of the supply pipe 32 can be received in the recesses 34. The end of the supply pipe 32 does not extend downwardly past the plane containing the axes of the advancing rollers 18.

[0020] The bag sealing members 22 are shown in detail in Fig. 2. One of the bag sealing members 22 mounts two vertically spaced heating elements 36. The other bag sealing member 22 carries two spring mounted parts 38 opposite the heating elements 36. Between the spring mounted parts 38 is provided a serrated blade 40. Below The heating elements 36, the bag sealing member 22 mounts a projection 42 with a resilient end and a similar projection 42 with a resilient end is spring mounted in an oppositely disposed position on the other bag sealing member 22. These parts are arranged such that when the piston 20 operates to bring the bag sealing members 22 together, the clamping projections 42 will engage first followed by the heating elements 36 and the spring mounted parts 36 followed by the serrated knife 40 engaging the bag.

[0021] In use then, the motor which drives the advancing rollers advances in steps. Once the rollers 18 have been advanced and stopped the pistons 20 are operated and the upright elements 26 are brought together at the open side of the material 14. Current is applied to the heating element 28 to heat seal the edges of the materiai which is urged against the heating element 28 by the spring mounted part 30. At the same time, the members 22 are brought together. As the members 22 are brought together, the clamping projections engage the bag material to close it off and the spring mounted parts 38 then urge the material against the heating elements 36 to heat seal the material in two vertically spaced positions. The serrated knife 40 then engages the bag to perforate between the two seals. The pistons 20 are then operated to retract the members 22 and arms 24 and the advancing rollers 18 are advanced again while compressed air is supplied through the pipe 32. When the cycle has been repeated, the first bag has been created. The bags are created in a strip and can be torn off at the perforated iine created by the knife 40.

[0022] It is seen that the clamping projections act to close off the area being sealed by the heating element 36 from back pressure from the bag which has just been formed so that the seals which are created are not subjected to that pressure until the seals have been formed and cooled to some degree. In this way a seal is reliably formed.

[0023] The supply pipe 32 and the recesses 34 in the rollers 18 are sized and spaced in relation to the thickness of the bag material 14 such that little or no air can escape backwards between the supply pipe 32 and the rollers 18 and thus the amount of air supplied to each bag can be controlled precisely and a uniform series of bags produced.

[0024] The supply pipe may supply compressed air at 20,7 KPa (3psi). The bag material may be any suitable heat sealable material which provides an air barrier and may be low density polyethylene (LDPE), for example. The sealing contact time may be 1.5 seconds.

[0025] The second embodiment is shown in Fig. 3 and is similar to the embodiment of Figs. 1 and 2. Only the differences from the first embodiment will be described and the same reference numerals will be used for equivaient features.

[0026] The only difference in the second embodiment is that the projections 42 are not provided on the bag members 22 but instead are provided on separately operated rams not shown). This enables greater and independent control over the delay between bag ciamping and bag sealing and cutting. It also makes the heating elements 36 easier to change.

Claims

1. Apparatus (10) for making a bag of gas for protective packing, the apparatus comprising a source of compressed gas, a compressed gas supply pipe (32) and two rollers (18) arranged side by side and between which material (14) for making a bag passes, one or both of the rollers including a circumferential recess (34) and the recess (34) or both recesses (34) together receiving the supply pipe (32).

2. Apparatus as claimed in claim 1, wherein the supply pipe (32) substantially fills the recess (34) or both recesses (34).

3. Apparatus as claimed in claim 1 or 2, wherein the bag material (14) is provided as a strip.

4. Apparatus as claimed in any of claims 1 to 3, wherein bag sealing means (22) is provided immediately downstream of the rollers (18).

5. Apparatus as claimed in claim 4, wherein the sealing means (22) comprises heating sealing means.

6. Apparatus as claimed in claim 1, wherein the gas source is a source of compressed air.

7. Apparatus as claimed in claim 4 or 5 in which clamping means (42) is provided for clamping the bag downstream of the sealing means.

8. Apparatus as claimed in claim 7, wherein the clamping means (42) comprises a resilient member (42) which is urged against the bag.

9. Apparatus as claimed in claim 8, wherein the clamping means (42) comprises two resilient clamping members (42) arranged on opposite sides to clamp a bag between them.

10. Apparatus as claimed in any of claims 7 to 9, wherein the clamping means (42) is arranged to clamp the bag before the sealing means starts to seal the bag.

11. Apparatus as claimed in any of claims 7 to 9, wherein a clamping member (42) of the clamping means and a sealing member (22) of the sealing means are mounted together on a mounting member.

12. Apparatus as claimed in claim 11, wherein on the mounting member, the clamping member (42) is resiliently mounted ahead of the sealing member (22) so as to engage the bag before the sealing member.

13. Apparatus as claimed in claim 11 or 12, wherein a second mounting member is provided which mounts one of a second clamping member (42) and a second sealing member (22).

14. Apparatus as claimed in claim 13, wherein only one of the first and second mounting members is movable.

15. Apparatus as claimed in claim 13, wherein both of the first and second mounting members are movable towards and away from each other.

16. Apparatus as claimed in any of claims 11 to 15, wherein the or each mounting member is moved pneumatically.

17. Apparatus as claimed in any preceding claim, wherein the apparatus is arranged to operate in a cycle.

18. Apparatus as claimed in any preceding claim, wherein the bag material (14) is in the form of two layers open at one side, the gas supply pipe (32) extending between the layers through the open side.

19. Apparatus as claimed in claim 18, wherein the material (14) is open on only one side.

20. Apparatus as claimed in claim 18 or 19, wherein means is provided for sealing the open side.

21. Apparatus as claimed in claim 20, wherein the open side of the material is sealed by side sealing means (28) upstream of the end of the supply pipe.

22. Apparatus as claimed in claim 21, wherein the side sealing means (18) comprises heat sealing means (28).

23. Apparatus as claimed in claim 21 or claim 22, wherein the side sealing means (28) comprises a member which is movable towards and away from the side of the material.

24. Apparatus as claimed in any of claims 20 to 23 wherein side sealing means (28) is provided for sealing the open side of the material upstream of the end of the supply pipe (32), and wherein the bag sealing means (22) and the side sealing means (28) are rigidly connected and movable together.

25. Apparatus as claimed in claim 24, wherein the bag sealing means (22) and the side sealing means (28) are movable by pneumatic means.

26. Apparatus as claimed in any preceding claim, wherein the apparatus includes means for advancing material for making a bag from a store.

Ansprüche

1. Vorrichtung (10) zur Herstellung eines Gaskissens für eine Schutzverpackung, welche Vorrichtung eine Quelle eines komprimierten Gases, eine Zufuhrleitung (32) für ein komprimiertes Gas und zwei Walzen (18) umfaßt, die nebeneinander liegend angeordnet sind und zwischen denen das Material (14) zur Herstellung eines Kissens hindurchgeht. wobei eine oder beide Walzen eine Umfangsnut (34) aufweist bzw. aufweisen und die Nut (34) oder beide Nuten (34) gemeinsam die Zufuhrleitung (32) aufnehmen.

2. Vorrichtung nach Anspruch 1, bei der die Zufuhrleitung (32) im wesentlichen die Nut (34) oder beide Nuten (34) ausfüllt.

3. Vorrichtung nach Anspruch 1 oder 2, bei der das Kissenmaterial (14) durch einen Streifen gebildet wird.

4. Vorrichtung nach einem der Ansprüche 1 bis 3, bei der eine Kissen-Siegeleinrichtung (22) unmittelbar stromabwärts der Walzen (18) vorgesehen ist.

5. Vorrichtung nach Anspruch 4, bei der die Siegeleinrichtung (22) Heißsiegeleinrichtungen umfaßt.

6. Vorrichtung nach Anspruch 1, bei der die Gasquelle eine Druckluftquelle ist.

7. Vorrichtung nach Anspruch 3 oder 4, bei der eine Klemmeinrichtung (42) vorgesehen ist zum Klemmen des Kissens stromabwärts der Siegeleinrichtung.

8. Vorrichtung nach Anspruch 7, bei der die Klemmeinrichtung (42) ein elastisches Bauteil (42) umfaßt, das gegen das Kissen gedrückt wird.

9. Vorrichtung nach Anspruch 8, bei der die Klemmeinrichtung (42) zwei federnde Klemmglieder (42) auf gegenüberliegenden Seiten zum Einklemmen eines Kissens zwischen beiden umfaßt.

10. Vorrichtung nach einem der Ansprüche 7 bis 9, bei der die Klemmeinrichtung (42) so ausgebildet ist, daß sie das Kissen klemmt, bevor die Siegeleinrichtung mit dem Siegeln des Kissens beginnt.

11. Vorrichtung nach einem der Ansprüche 7 bis 9, bei der ein Klemmglied (42) der Klemmeinrichtung und ein Siegelglied (22) der Siegeleinrichtung gemeinsam auf einem Trägerteil montiert sind.

12. Vorrichtung nach Anspruch 11, bei der auf dem Trägerteil das Klemmglied (42) federnd vor dem Siegelglied (22) angeordnet ist und das Kissen vor dem Siegelglied erfaßt.

13. Vorrichtung nach Anspruch 11 oder 12, bei der ein zweites Trägerteil vorgesehen ist, an dem ein zweites Klemmglied (42) oder ein zweites Siegelglied (22) befestigt ist.

14. Vorrichtung nach Anspruch 13, bei der nur eines der ersten und zweiten Trägerteile beweglich ist.

15. Vorrichtung nach Anspruch 13, bei der sowohl das erste als auch das zweite Trägerteil zueinander und auseinander beweglich sind.

16. Vorrichtung nach einem der Ansprüche 11 bis 15, bei der das oder jedes Trägerteil pneumatisch beweglich ist.

17. Vorrichtung nach einem der vorhergehenden Ansprüche, bei der die Vorrichtung so ausgebildet ist, daß sie zyklisch arbeitet.

18. Vorrichtung nach einem der vorhergehenden Ansprüche, bei der das Kissenmaterial (14) die Form von zwei Lagen mit einer offenen Seite aufweist, wobei sich die Gaszufuhrleitung (32) durch die offene Seite zwischen die Lagen erstreckt.

19. Vorrichtung nach Anspruch 18, bei der das Material (14) auf nur einer Seite offen ist.

20. Vorrichtung nach Anspruch 18 oder 19, bei der eine Einrichtung zum Siegeln der offenen Seite vorgesehen ist.

21. Vorrichtung nach Anspruch 20, bei der die offene Seite des Materials durch eine Seitensiegeleinrichtung (28) stromaufwärts des Endes der Zufuhrleitung siegelbar ist.

22. Vorrichtung nach Anspruch 21, bei der die Seitensiegeleinrichtung (28) eine Heißsiegeleinrichtung (28) umfaßt.

23. Vorrichtung nach Anspruch 21 oder 22, bei der die Seitensiegeleinrichtung (28) ein Bauteil umfaßt, das in Richtung der Seite des Materials und zurück beweglich ist.

24. Vorrichtung nach einem der Ansprüche 20 bis 23, bei der eine Seitensiegeleinrichtung (28) zum Siegeln der offenen Seite des Materials stromaufwärts des Endes der Zufuhrleitung (32) vorgesehen ist, und bei der die Kissensiegeleinrichtung (22) und die Seitensiegeleinrichtung (28) starr miteinander verbunden und gemeinsam beweglich sind.

25. Vorrichtung nach Anspruch 24, bei der die Kissensiegeleinrichtung (22) und die Seitensiegeleinrichtung (28) durch pneumatische Einrichtungen beweglich sind.

26. Vorrichtung nach einem der vorhergehenden Ansprüche, bei der die Vorrichtung eine Einrichtung zum Vorrücken des Materials zur Herstellung eines Kissens vom Lager aufweist.

Revendications

1. Appareil (10) pour la confection d'un sachet rempli de gaz pour un emballage de protection, appareil comprenant une source de gaz comprimé, un conduit d'alimentation (32) en gaz et deux rouleaux (18) disposés côte à côte et entre lesquels passe le matériau (14) pour la confection du sachet, l'un des rouleaux ou les deux présentant un retrait (34) périphérique et le conduit d'alimentation (32) étant logé dans le retrait (34) ou simultanément dans les deux retraits (34).

2. Appareil selon la revendication 1, dans lequel le conduit d'alimentation (32) remplit sensiblement le ou les deux retraits (34).

3. Appareil selon la revendication 1 ou 2, dans lequel le matériau (14) pour la confection des sachets est fourni sous forme de bande.

4. Appareil selon l'une quelconque des revendications 1 à 3, dans lequel un moyen de soudage (22) de sachets est disposé immédiatement en aval des rouleaux (18).

5. Appareil selon la revendication 4, dans lequel moyen de soudage (22) comprend un moyen de soudage par la chaleur.

6. Appareil selon la revendication 1, dans lequel la source de gaz est une source d'air comprimé.

7. Appareil selon la revendication 4 ou 5, dans lequel un moyen de serrage (42) pour serrer le sachet est disposé en aval du moyen de soudage.

8. Appareil selon la revendication 7, dans lequel le moyen de serrage (42) comporte une pièce élastique qui est poussée contre le sachet.

9. Appareil selon la revendication 8, dans lequel le moyen de serrage (42) comporte deux pièces élastiques (42) de serrage en regard pour serrer un sachet entre elles.

10. Appareil selon l'une quelconque des revendications 7 à 9, dans lequel le moyen de serrage (42) est prévu pour serrer le sachet avant que le moyen de soudage ne commence à le souder.

11. Appareil selon l'une quelconque des revendications 7 à 9, dans lequel une pièce de serrage (42) du moyen de serrage et un élément de soudage (22) du moyen de soudage sont montés tous les deux sur un support de montage.

12. Appareil selon la revendication 11, dans lequel la pièce de serrage (42) est montée de façon élastique sur le support de montage en avant de l'élément de soudage (22) de manière à mettre en prise le sachet avant l'élément de soudage.

13. Appareil selon la revendication 11 ou 12, dans lequel on prévoit un deuxième support de montage sur lequel est montée l'une d'une deuxième pièce de serrage (42) et un deuxième élément de soudage (22).

14. Appareil selon la revendication 13, dans lequel l'un seulement des premier et second supports de montage est mobile.

15. Appareil selon la revendication 13, dans lequel les deux des premier et deuxième supports de montage sont mobiles l'un vers l'autre et l'un à l'encontre de l'autre.

16. Appareil selon l'une quelconque des revendications 11 à 15, dans lequel le ou chacun des supports de montage est déplacé pneumatiquement.

17. Appareil selon l'une quelconque des revendications précédentes, dans lequel l'appareil est conçu pour travailler selon un cycle.

18. Appareil selon l'une quelconque des revendications précédentes, dans lequel le matériau pour sachet (14) se présente sous la forme de deux couches ouvertes d'un côté, le conduit d'alimentation en gaz (32) s'étendant entre les couches à travers le côté ouvert.

19. Appareil selon la revendication 18, dans lequel le matériau (14) n'est ouvert que d'un côté.

20. Appareil selon la revendication 18 ou 19, dans lequel on prévoit un moyen pour souder le côté ouvert.

21. Appareil selon la revendication 20, dans lequel le côté ouvert du matériau est soudé par un moyen de soudage latéral (28) en amont de l'extrémité du conduit d'alimentation.

22. Appareil selon la revendication 21, dans lequel le moyen de soudage latéral (18) comprend un moyen de soudage par la chaleur (28).

23. Appareil selon la revendication 21 ou 22, dans lequel le moyen de soudage latéral (28) comprend un élément mobile vers et à l'encontre de la face latérale du matériau.

24. Appareil selon l'une quelconque des revendications 20 à 23, dans lequel on prévoit un moyen de soudage latéral (28) pour souder la face ouverte du matériau en amont de l'extrémité du conduit d'alimentation (32), et dans lequel le moyen de soudage (22) du sachet et le moyen de soudage latéral (28) sont reliés rigidement et déplaçables en bloc.

25. Appareil selon la revendication 24, caractérisé en ce que le moyen de soudage (22) de sachets et le moyen de soudage latéral (28) sont déplaçables par un moyen pneumatique.

26. Appareil selon l'une quelconque des revendications précédentes, dans lequel l'appareil comprend un moyen pour faire avancer le matériau afin de confectionner un sachet à partir d'un magasin.

Drawing