GB2490368A

GB2490368A - Opening a packing bag by blowing air.

Info

Publication number: GB2490368A
Application number: GB1110266.2A
Authority: GB
Inventors: Philippe Blanc
Original assignee: Maf Agrobotic SAS
Current assignee: Maf Agrobotic SAS
Priority date: 2011-04-29
Filing date: 2011-06-17
Publication date: 2012-10-31
Also published as: GB201110266D0; FR2974567A1; ZA201104668B

Abstract

A device for opening a packing bag 25 folded flat comprising means for blowing air 34 in the direction of the end mouth 26 of the bag 25, and a pinching device 38 adapted to be able to pinch at a distance from the end mouth 26 an entire width of the end section of the folded bag, said end section being at least substantially impermeable to gas flows. This ensures the opening of the end mouth 26 under the effect of blowing means 34 regardless of the gas-permeability characteristics of the walls of the bag extending beyond the said end section.

Description

I

DEVICE FOR THE OPENING BY BLOWING AIR OF A PACKING BAG

FOLDED FLAT AND BAGGING MACHINE PROVIDED WITH AT LEAST ONE

SUCH DEVICE

S The invention relates to a device for opening a packing bag folded flat, this packing bag having an end mouth and an end section at least substantially impermeable to gas flows and extending from the said end mouth. It covers a bagging machine provided with at least one such opening device.

Machines f or automatically bagging articles such as fruit or vegetables, enabling bags to be filled automatically with predetermined quantities of articles, are already known (US 4253292, FR 2148176, etc.). Such machines have, in particular, a device for automatically opening a packing bag folded flat comprising means for blowing air in the direction of the end mouth of the bag. The blown air inflates the bag and brings about the opening of the end mouth, which enables the bag to be filled with articles fed by a chute. Mostly, there is provided a plate for receiving a bundle of bags folded flat stacked on one another and held in place on the receiving plate by a holding device cooperating with an end strip of each bag extending beyond the end mouth. The bag which is opened by the opening device is that which is arranged at the top of the bundle (or more generally opposite the receiving plate), and the bags of the bundle are opened and filled successively. In addition, spreading members such as hooks may be provided to keep the end mouth open after the latter has been opened by the blowing means.

These known devices work satisfactorily provided that the walls of the packing bag are impermeable to gas flows, that is to say sufficiently gas-tight so that the blowing of air towards the end mouth brings about its inflation and opening effectively. it should be noted that this impermeability to gas flows does not strictly require total gas-tightness. it actually suffices that the air flow is sufficient, compared with the possible permeability of the walls, to be able to bring about the Opening of the end mouth.

Nevertheless, some packing bags have, beyond an end section at least substantially impermeable to gas flows and extending from the end mouth, considerably openworked walls so as to avoid especially any form of condensation in the bag after packing. These openworked walls prevent inflation of the bag under the effect of the air blowing and the opening of the end mouth. Consequently, the known devices and machines are not compatible with such packing bags.

The invention aims to overcome these disadvantages by proposing an opening device and a bagging machine which can be used with a wide range of packing bags, including packing bags having openworked walls, permeable to gas flows, extending from an end section at least substantially impermeable to gas flows.

The invention aims to solve this problem for a low cost and without impairing the performance of the bagging machine.

To this end, the invention relates to a device for opening a packing bag folded flat having an end mouth and an end section at least substantially impermeable to gas flows and extending from the end mouth, this device comprising means for blowing air in the direction of the said end mouth, characterised in that it comprises a pinching device adapted to be able to pinch at least part of the width of the end section of the bag folded flat, at a distance from the end mouth, so as to ensure the opening of the latter under the effect of the blowing means regardless of the gas-permeability characteristics of the walls of the bag extending beyond the said end section.

Advantageously and according to the invention, the pinching device is adapted to be able to pinch at least the major part of the width -especially the entire width -of the end section of the bag. in any case, the part of the width of the end section of the bag which is pinched by the pinching device must be sufficient to ensure the opening of the end mouth by inflation under the effect of the blowing means. It should indeed be noted that, according to the invention, it actually suffices to perform a pinching which is sufficient for the air flow supplied by the blowing means to bring about the opening of the end mouth by inflation.

Such a pinching device may have a large number of different embodiments. it may be, for example, two pinching bars brought towards one another, or even an air curtain extending along the width of the bag and oriented towards the latter, etc. Nevertheless, advantageously and according to the invention, the pinching device comprises: -a plate for receiving at least one bag folded flat, -a pinching bar mounted to be movable relative to the receiving plate at least between an inactive position remote from the latter and a pinching position close to the receiving plate, parallel to the latter and at least substantially orthogonal to the direction of the air delivered by the blowing means, -an actuator of the pinching bar capable of displacing the S pinching bar between the inactive and pinching positions.

For example, advantageously and according to the invention, the pinching bar is a crosspiece of a framework mounted to be movable in rotation relative to a frame secured to the receiving plate. The pinching bar preferably has a length greater than the width of the end section of a bag.

In particular, this embodiment is advantageously adapted to an opening device enabling the bags of a bundle of bags stacked folded flat to be received and processed successively. Thus, advantageously and according to the invention, the receiving plate is provided with a device for holding in place, relative to the receiving plate, an end strip extending beyond the end mouth of each bag of a bundle of bags stacked folded flat on one another.

In addition, advantageously, a device according to the invention has at least one spreading member capable of cooperating with a wall of the bag forming the end mouth so as to keep it open, and an actuator capable of displacing each spreading member so as to bring about its cooperation with the end mouth when the blowing means are active. Thus, such a spreading member can ensure that the end mouth is kept in the open position immediately after it has been opened under the effect of the blowing means and the pinching device, and then when the pinching device is returned to the inactive position for the filling of the articles into the bag.

It should be noted that such a spreading member is not always necessary, especially in the case where the walls of the packing bag are sufficiently impermeable to gas flows for the end mouth to be kept open under the effect of the blowing means even when the pinching device is returned to the inactive position.

The fact that at least one such spreading member is provided nevertheless makes it possible to ensure the operation of the opening device whatever the permeability characteristics of the walls of the packing bags. Moreover, the blowing means can be switched off immediately after the opening of the end mouth, so that they do not interfere with the filling of the articles into the bag.

Such a spreading member may have a large number of different embodiments: pincers, suckers, etc. In a preferred embodiment, a device according to the invention has, as the spreading member, at least one hook capable of engaging in the end mouth arid of retaining a wall of the bag forming the end mouth so as to keep it open.

Furthermore, advantageously, a device according to the invention has a unit for controlling each actuator, which unit is adapted to be able to: -activate the pinching device in order to place it in the pinching position, -then trigger the blowing means so as to bring about an opening of the end mouth, -then activate the actuator of each spreading member so as to enable its cooperation with the end mouth and the keeping of the latter in the open position, -then activate the pinching device in order to place it in the inactive position.

Advantageously, the blowing means may also be inactivated as soon as each spreading member cooperates with the end mouth to keep it open. At the end of these various steps, the packing bag situated at the top of the bundle (opposite the receiving plate) is opened and kept open so that its filling can be carried out.

The invention covers a machine for bagging articles such as fruits or vegetables, characterised in that it comprises at least one bag opening device according to the invention.

Advantageously, a machine according to the invention comprises a device for feeding each opening device with articles to be bagged.

The invention also relates to a bag opening device and a bagging machine, characterised by all or part of the features mentioned above or below in combination.

Further aims, features and advantages of the invention will become apparent on reading the following non-limiting description of an embodiment of the invention shown in the appended figures in which: -Figure 1 is a schematic perspective view of an example of a bagging machine according to the invention provided with a device according to the invention, -Figure 2 is a schematic perspective view of an example of a bag folded flat which can be used with a machine and a device according to the invention, -Figure 3 is a schematic perspective view of the machine of Figure 1 shown from another viewing angle and without a bag, Figure 4 is a schematic perspective view showing in greater detail the device of Figure 1 according to the invention, with the pinching device in the pinching position and the air blowing means activated, the spreading members still being inactive, -Figure 5 is a view similar to Figure 4 showing the spreading members engaged in the end mouth of the bag from the state of Figure 4, -Figure 6 is a view similar to Figure 4 showing the pinching device raised into the inactive position from the state of Figure 5.

The bagging machine 21 according to the invention shown in the figures comprises a device 22 according to the invention for automatically opening a packing bag. This bag opening device 22 comprises a receiving plate 23 adapted to receive a bundle 24 of packing bags folded flat stacked on one another.

Traditionally1 each packing bag 25 has an end mouth 26 and an end section 27 extending from the end mouth 26 and formed of an unperf orated continuous film which is gastight or, in any case, impermeable to gas flows. This end section 27 serves, in particular, to receive a tie for closing the end mouth 26 after the filling of the bag. The end section 27 is continued towards the bottom 29 of the bag by walls which can be at least partially perforated or formed of a mesh, so that they are air-permeable. Such a packing bag can be formed of a polymeric synthetic material film (for example polyethylene) or of paper or other material.

The end mouth 26 is, furthermore, continued by an end strip 28 extending beyond the end mouth 26 opposite the bottom 29 off the bag. This end strip 28 is provided with perforations 31 allowing a clip 32 to pass through in order to fix the bundle 24 of bags on the receiving plate 23.

The machine also comprises a chute 33 for feeding articles which opens out in a manner facing the end mouth 26 of the bag 25 arranged at the top of the bundle 24 placed on the receiving plate 23.

On the axis of the chute 33, the machine bears at least one nozzle 34 for blowing compressed air, which is adapted to direct a compressed-air flow in the direction of the end mouth 26 of the bag 25 in order to open this end mouth 26 by inflating the end section 27 of the bag 25.

A pinching framework 35 is mounted rotatably relative to the machine frame about an axis 36 orthogonal to the direction of the compressed-air flow delivered by the blowing nozzle 34 and above the receiving plate 23. A pneumatic cylinder 37 is interposed between the machine frame and one of the arms of the pinching frame 35 so as to be able to displace it in rotation about the axis 36. The pinching framework 35 can thus be displaced between an inactive raised position (Figures 1 and 3) and a lowered pinching position towards the receiving plate 23 (Figure 4), in which a crosspiece of the framework 35 is pressed against the end section 27 of the bag 25 at a distance from the end mouth 26 and thus forms a bar 38 for pinching the end section 27 of the bag 25.

The pinching bar 38 extends parallel to the axis of rotation 36 and orthogonally to the direction of the compressed-air flow delivered by the blowing nozzle 34, that is to say along the width of the bag 25. The pinching bar 38 is adapted to pinch the entire width of the end section 27. In the pinching position, it is pressed towards the receiving plate 23 and against this end section 27 so that the air blown by the blowing nozzle 34 cannot pass beyond the portion thus pinched. Since the end section 27 is impermeable to gas flows, it inflates and thereby brings about the opening of the end mouth 26.

Advantageously, the opening device 22 also comprises a pair of spreading hooks 39 rotationally fixed to a shaft 40 mounted rotatably relative to the frame about an axis horizontal and orthogonal to the direction of the air flow delivered by the blowing nozzle 34. The hooks 39 are arranged above the receiving plate 23, substantially above the clip 32 for fixing the bundle 24, so as to be able to engage in the end mouth 26 of the bag 25 situated at the top of the bundle 24 when this end mouth 26 is opened under the effect of the blowing nozzle 34. The shaft 40 and the hooks 39 are displaced in rotation by a pneumatic cylinder 41 interposed between the frame and a link 42 secured to the shaft 40. A counterweight 43 is advantageously provided to balance the assembly rotationally.

The machine according to the invention comprises a control unit 44 adapted to control the various actuators and the blowing nozzle 34.

The device according to the invention operates as follows.

Initially, the pinching framework 35 is in the inactive position as shown in Figures 1 and 3. In this position, it is possible to place a bundle 24 of bags on the receiving plate 23 and fix this bundle by means of the clip 32. The pinching framework 35 is then actuated by the control unit 44 into the pinching position shown in Figure 4. The blowing nozzle 34 is then activated by the control unit 44, whereby the end mouth 26 is opened by inflation of the end section 27 of the bag 25 situated at the top of the bundle 24. This inflation is made possible by the fact that the end of the end section 27 is pinched by the pinching bar 38. The control unit 44 then actuates the hooks 39 such that they engage in the end mouth 26 thus opened, in order to keep it open. The blowing nozzle 34 can then be shut off. The pinching framework 35 is then returned to the inactive position so as not to impede the filling of the bag 25 thus opened. The articles filling the bag are delivered by the feeding chute 33. When the bag is full, a user can take hold of it, detach it from the bundle (by tearing the end strip 28 at the perforations 31) and close the end mouth 26 again by means of a closing tie, which may be an adhesive tape placed around the end section 27 with the aid of an adhesive tape-applying device 45 borne by the machine frame above the opening device 22.

It goes without saying that the invention may have numerous alternative embodiments to the embodiment shown in the figures by way of non-limiting example. In particular, the pinching bar 38 may be displaced directly in translation by a cylinder (and not in rotation), and it may be replaced by any other pinching member such as a cable, a plate, a compressed-air curtain, etc. Likewise, the hooks 39 may be omitted or replaced by any other spreading member. The receiving plate 23 may be horizontal, inclined as shown, or even vertical. The machine may be equipped with a robot for automatic closing and/or handling of the bags after filling, with a device for weighing the articles before they are fed into the bags, etc. The various cylinders may be pneumatic, hydraulic, or replaced by electric motors or any other actuator, etc. The blowing nozzle 34 can be replaced by a plurality of nozzles, or by any other air blowing device capable of inflating the end section 27 of each bag 25.

Claims

CLAIMS1. A device for opening a packing bag folded flat having an end mouth (26) and an end section (27) at least substantially impermeable to gas flows and extending from the end mouth, this device comprising means (34) for blowing air in the direction of the said end mouth (26), characterised in that it comprises a pinching device (38) adapted to be able to pinch at least part of the width of the end section of the bag folded flat, at a distance from the end mouth (26), so as to ensure the opening of the latter under the effect of the blowing means (34) regardless of the gas-permeability characteristics of the walls (30) of the bag extending beyond the said end section (27).
2. A device according to Claim 1, characterised in that the pinching device (38) is adapted to be able to pinch the entire width of the end section (27) of the bag.
3. A device according to any one of Claims 1 or 2, characterised in that the pinching device (38) comprises: -a plate (23) for receiving at least one bag folded, flat, -a pinching bar (38) mounted to be movable relative to the receiving plate (23) at least between an inactive position remote from the latter and a pinching position close to the receiving plate (23), parallel to the latter and at least substantially orthogonal to the direction of the air delivered by the blowing means (34), -an actuator (37) of the pinching bar (38) capable of displacing the pinching bar (38) between the inactive and pinching positions.
4. A device according to Claim 3, characterised in that the pinching bar (38) is a crosspiece of a framework (35) mounted to be movable in rotation relative to a frame secured to the receiving plate (23).
5. A device according to any one of Claims 3 or 4, characcerised in that the receiving plate (23) is provided with a device (32) for holding in place, relative to the receiving plate, an end strip (28) extending beyond the end mouth of each bag of a bundle (24) of bags stacked folded flat on one another,
6. A device according to any one of Claims I to 5, characterised in that it comprises at least one spreading member (39) capable of cooperating with a wall of the bag forming the end mouth (26) so as to keep it open, and an actuator (41) capable of displacing each spreading member (39) so as to bring about its cooperation with the end mouth (26) when the blowing means (34) are active.
7. A device according to Claim 6, characterised in that it comprises, as the spreading member (39), at least one hook (39) capable of engaging in the end mouth (26) and of retaining a wall of the bag forming the end mouth so as to keep it open.
8. A device according to any one of Claims 6 or 7, characterised in that it has a unit (44) for controlling each actuator, which unit is adapted to be able to: -activate the pinching device (38) in order to place it in the pinching position, -then trigger the blowing means (34) so as to bring about an opening of the end mouth (26), -then activate the actuator (41) of each spreading member (39) so as to enable its cooperation with the end mouth (26) and the keeping of the latter in the open position, -then activate the pinching device (38) in order to place it in the inactive position.
9. A machine for bagging articles such as fruits or vegetables, characterised in that it comprises at least one bag opening device (22) according to any one of Claims 1 to 8.
10. A machine according to Claim 9, characterised in that it comprises a device for feeding each opening device with articles to be bagged.