IE53864B1

IE53864B1 - Process and device for gripping by suction

Info

Publication number: IE53864B1
Application number: IE53/83A
Authority: IE
Original assignee: Carnaud Amballage
Priority date: 1982-01-11
Filing date: 1983-01-11
Publication date: 1989-03-29
Also published as: DK6783A; IT8319059A0; ES8308797A1; DK158091C; FR2519619A1; EP0084479B1; GB8300586D0; EP0084479A1; IT1193605B; GR77876B; ES518904A0; BE895565A; FR2519619B1; GB2113178A; DK6783D0; DE3362570D1; DK158091B; IE830053L

Abstract

1. A gripping process of the kind using a source of suction, for picking up a load which comprises a plurality of objects arranged in a layer by confining a volume covering the load to be picked up, characterised by placing this volume in communication with the suction source and continuously drawing air through the load which is thus confined with an air flow rate so determined as to ensure that the load is held by the pressure reduction created between the bottom and the top of the load by the pressure drop in the flow, which pressure drop is essentially localised and is determined at the level of the load to be picked up.

Description

The present invention relates in general terms to the picking up of a load which can comprise a plurality of objects arranged in a layer.

It relates more particularly, but not exclusively, to the ease where several layers of such objects are superimposed, if appropriate with spacers interposed between successive layers.

This is the case, in particular, of objects stacked in successive layers on a handling pallet.

To remove such objects from the pallet layer by layer, it is known to use gripping, devices which use a source of suction for picking up objects simultaneously from the same layer.

In practice, a gripping device of this type consists of a suction hood which, closed by a perforated bottom at the level of its lower edge, is applied by this bottom against all the objects to be picked up from the same layer.

A gripping device of this type is suitable, in particular, if the objects to be picked up are hollow objects, for example bottles, presented mouth up; in fact, provided at least one perforation in the bottom of the hood is located opposite the mouth of one such object, a pressure reduction is created inside the object when the suction hood is applied thereto, and this pressure reduction holds the object against the bottom of the said hood, fixes it temporarily thereto and hence enables it to be carried away together with this hood, raised for this purpose, the bottom of the said hood then simply o .. - 2 forming a barrier locally securing this object mechanically in opposition to the source of suction to which the hood is connected.

The device is also suitable if the objects to be picked up possess, at least locally, for the application of the perforated bottom of the suction hood^ any surface delimited by a contour located in a plane and thus suitable for leaktight application to this bottom around at least one of the perforations in the latter.

However, a gripping device of this type, which, in practice, for picking up a plurality of objects simultaneously, handles each of them individually, can prove inadequate if these objects are of arbitrary configuration, and/or, in the case of hollow objects, if the orientation with which these objects present their mouth to the suction hood is arbitrary, it being possible in this case for this mouth not to enter the perforations in the bottom of this suction hood.

Moreover, during the removal of objects stacked on a pallet in successive layers, the device is not capable of removing, together with the objects in the same layer, the spacer which may be interposed between this layer and the next, so that, in this case, an additional, special and inevitably costly operation must be carried out in order to effect this removal.

The present invention relates in general terms to an arrangement which makes it possible to overcome these di sadvantages.

More precisely, it relates firstly to a gripping xJ ‘»· process for picking up a Load uhich can comprise a plurality of objects arranged in a layer, this process being of the type in whieh a source of suction is used and being characterised in that the load to be picked up is covered laterally, at least in part, by a lateral means of confinement determining, above the load, a volume uhich is under reduced pressure since it is in direct communication with the source of suction, while communication uith the atmosphere is substantially obstructed by the load covered in this way.

It also relates to a gripping device which is of the type using a source of suction and which is characterised in that it comprises a lateral means of confinement suitable for covering laterally, at least in part, the load to be picked up.

Thus, according to the invention and because of the fact that a lateral means of confinement, arranged around the load to be picked up, confines the volume in which the pressure reduction due to the source of suction exerts its effects, the gripping of the load takes place not individually, object by object, by application of the said pressure reduction to each of these objects, but universally, for all these objects, by the drop in pressure of the fluid flowing around the latter, in the passage area delimited by the said lateral means of confinement.

Thus, the efficacy of the gripping to be provided is independent of the configuration and/or the relative orientation of the objects which can make up the load to be picked up, the only factor which intervenes being the passage area left free between these objects and between the latter and the lateral means of confinement which surrounds them.

Therefore, objects of arbitrary configuration and/or relative orientation can advantageously be handled Moreover, if desired, in the case of objects stacked in superimposed layers with a spacer interposed between two successive layers, it is advantageously possible, according to the invention, to remove this spacer together with the objects which are on top of it.

In fact, it then suffices to ensure, by means of the source of suction used, that not only the objects in such a layer, but also the spacer underneath these objects, are carried away.

The process according to the invention is thus characterised in general terms in that the air flow sucked through a chosen load surrounded by the lateral means of confinement is determined so as to ensure that the load is held by the pressure reduction created on the upper face of the said load because of the drop in pressure of the flow through the latter and, if appropriate, between this load and the lateral means of confinement.

The characteristics and advantages of the invention will moreover become apparent from the description which now follows, by way of example, with reference to the simplified drawings attached, in which: - Figure 1 is a view in elevation of a gripping - 5 device according to the invention, with a local cut-away; - Figure 2 is a view in e levati on/secti on of a layer of objects capable of being picked up by a gripping device of this type; - Figure 3 is a view in elevation/section of the gripping device according to the invention, illustrating its mode of operation; - Figure 4 is a view of this gripping device in cross-section along the line IV-IV of Figure 3; - Figure 5 is a similar view to that of Figure 3, for a modified embodiment; and - Figure 6 is, on a larger scale, a partial view in elevation/section of a gripping device according to the invention, according to another embodiment thereof.

Figures 1 to 4 illustrate, by way of example, the application of the invention to the removal of containers 10, of the can type, from a pallet, which containers, in this embodiment, have a substantially square cross-section with widely rounded corners and possess an eccentric spout 11 in the top part, in one of the corners of such a section.

These containers 10 are stacked in superimposed layers on any kind of pallet, whieh is not shown in the figures but which, by way of example, is assumed to be of substantially square contour.

Only one sueh layer of containers 10 is shown in Figure 2, and, by way of example, a boat-shaped spacer 12 is associated therewith in this figure, the said spacer being intended for separating the layer from the layer 3 C 6 / - 6 underneath. This spacer is sometimes only a simple plane sheet.

Within such a layer, the containers 10 are arranged side-by-side, being juxtaposed in pairs by their respective faces.

In particular because of the round-off of their cross-section, the containers create passages 14 between them, which, for greater clarity, have been shown by shading in Figure 4.

Because of their eccentricity, the spouts 11 of the containers 10 are, in plan, for the layer formed by these containers 10, arranged in a random manner according to the relative angular orientation of the containers .

For removal from the pallet, all the containers in the same layer must be picked up simultaneously.

The gripping device 15 used for this purpose according to the invention uses a source of suction, in a manner which is in itself known.

This is, for example, a fan 16, the aspirating mouth of which has been shown diagrammatically by 17.

This fan 16 is arranged in the top part of a suction hood 18, a suitably controlled device 19 for communication with the atmosphere being intercalated be25 tween the fan and the suction hood in the illustrative embodiment shown.

These arrangements are in themselves well known, and as they are not based on the present invention, they will not be described in detail here. li 3 ι_· ί* 4 - 7 Their construction, moreover, is simply based on the field of those skilled in the art.

In a manner which is also in itself known, the suction hood 18, in the embodiment shown in Figures 1 to 4, is closed at its base by a perforated bottom 20 capable of forming a barrier suitable for mechanically securing the containers to be picked up, in opposition to the source of suction formed by the fan 16.

This bottom can be, for example, a suitably per10 forated metal sheet, a mesh, a system of wires, or any other device forming a suitable barrier.

Whatever the case may be, the contour of the base of the suction hood 18, and hence of its perforated bottom 20, is similar to that of the layer of containers to be picked up.

Thus, in the illustrative embodiment shown, the contour is substantially square.

According to the invention, the gripping device 15 comprises a lateral means of confinement, or skirt, 22, by means of which it is capable of laterally covering, at least in part, the whole of the layer of containers 10 to be picked up.

As shown in Figures 1 to 4, this skirt can be, for example, a simple vertical downward extension, beyond the perforated bottom 20, of the side walls of the suction hood 18, which form overall a truncated pyramid.

A skirt 22 of this type is therefore rigid in this case.

Whatever the case may be, it extends, in practice, to the periphery of the mechanical securing barrier formed by the perforated bottom 20 of the suction hood 18, and its contour is similar to that of this bottom.

According to arrangements which, as they do not form part of the present invention and are only based simply on the field of those skilled in the art, will not be described in detail here, the gripping device 15 formed in this way is, as a whole, mounted so as to move between two positions, the one being a removal position and the other an unloading position.

For its removal position, it laterally covers the whole of the layer of containers 10 to be picked up, as mentioned above.

In other words, for this removal position, the skirt 22 of this gripping device 15 surrounds the whole of the layer of containers 10 to be picked up, as illustrated in Figures 3 and 4.

A skirt 22 of this type, which forms a continuous unit with the suction hood 18, thus laterally confines the escape path left free for the suction fluid.

In Figure 4 and, as previously, for greater clarity, the passages 24 thus delimited by the skirt 22, between the latter and those containers 10 which are at the periphery of the layer formed by all these containers 10, have been represented by shading.

With the gripping device 15 thus in the removal position, the source of suction formed by the fan 16 is brought into action and, according to the invention, this source of suction is made to ensure a sufficient suction rate to establish the pressure reduction necessary for carrying away the containers 10 in question, on either side of the passage area formed by the difference between, on the one hand, the total cross-section of the skirt 22, and, on the other hand, that part of the tatter which is blocked by the said containers.

As will have been understood, this passage area is formed by the passages 14 and 24 specified above and represented by shading in Figure 4.

The gripping device 15 is then caused to move, first vertically and then, if appropriate, laterally, until it reaches its unloading position.

By virtue of the pressure reduction generated by the fan 16, the containers 10 are carried away, all together, without it being necessary, as in the prior art, for any reduced pressure to be exerted on each individual container.

This carrying-auay action is thus, in particular, independent of the location of the spouts 11 of the containers, relative to the perforations in the bottom 20 of the suction hood 18.

As specified above, the only purpose of this bottom 20 in the case in question is simply to ensure that the containers 10 are mechanically secured in respect of the suction to which they are subjected.

If desired, the fan 16 constituting the source of suction can be made to ensure that not only are the containers 10 carried away, as described above, but also the spacer 12 underneath them is carried away. 5386^ - 10 Subsequently, during the movement of the gripping device 15, any suitable means can be used to separate this spacer 12 from the containers 10.

By way of exampLe, and as illustrated in Figure 3, mechanical means, such as fingers 25, can be used, which are placed in the path which is then followed by the spacer 12, in order to retain the tatter. By taking advantage of its flexibility, it can be released gradually starting from its periphery.

However, it is also possible to use blast nozzles which are carried by the suction hood 18 and are capable of projecting a jet of fluid towards the spacer 12 so as to effect the desired removal of the latter, or, again, suction nozzles which are applied against the lower face of this spacer 12.

Whatever the case may be, when the gripping device 15 has arrived in the release position, the reduced pressure is cancelled, in particular by means of one of the following operations: stopping of the fan 16, bringing into action of the device 19 for communication with the atmosphere, or closing of the aspirating mouth 17.

The containers 10 previously picked up by this gripping device 15 are then released by it. fo pick up the objects while leaving in position the support on which they are placed (spacer, table or the like), the latter must consequently be perforated by any suitable means, either by perforations in the spacer or, in the ease of a table and by way of example, by noncontiguous planks, a perforated metal sheet, or the like .

The bottoms 20 of the gripping device according to the invention are markedly more perforated than those of the prior art. In fact, according to the earlier processes, any hole uhich did not end over the object to be picked up led to leaks and proved disadvantageous: low levels of perforation, always of less than SOX, were thus used. In contrast, according to the present invention, each hole contributes towards the pressure reduction above the objects to be picked up, and also reduces z the drop in pressure on either side of this bottom. High levels of perforation, which can approach 100%, are thus recommended; the bottom can then consist of a mesh.

In the foregoing, it has been assumed that the source of suction used exerts its effects on the con15 tainers 10 through a perforated bottom.

This is not necessarily the case, by virtue of the presence, according to the invention, of a skirt 22.

In contrast, and as illustrated diagrammaticaI ly in figure 5, it is possible, as shoun diagrammatically by an arrow in this Figure 5, for the connection of the aspirating mouth of the fan constituting the source of suction to be formed laterally relative to the volume de limited by the skirt 22 according to the invention and by the bottom 20 at whose periphery the skirt is formed.

Z5 This bottom 20 can thus be solid without any per foration.

The corresponding gripping device is thereby simplified, the suction hood, in particular, being dispensed with. ϊ» <» ν· In the application example illustrated in Figure 5, the containers to be picked up are bottles, which are assumed to be of circular cross-section, for example.

In the foregoing, it has been assumed that the skirt 22 according to the invention is rigid and that it is rigidly fixed to the gripping device 15 equipped t herewi th.

This is not necessarily the case.

On the contrary, if desired, at least part of this skirt 22 can move between a removal configuration, in which it is capable of being placed laterally against at least part of those objects to be picked up uhich are at the periphery of the assembly formed by the objects, and an unloading configuration, in which it is at a distance from the said objects.

For example, and as illustrated diagrammatically in Figure 6, at least one of the wall's 27 of this skirt 22, and, in practiee,' each of the said walls, forms a flap articulated by means of a hinge 28 on a support spindle 29 fixed to the suction hood 18 used in the illustrative embodiment shown in this Figure 6.

When the associated source of suction is in action, the walls 27 of the skirt 22 are automatically placed against those objects to be pieked up uhich are at the periphery of the assembly formed by the objects.

When the action of this source of suction 1s interrupted, the walls are free to move away from the said objects.

For example, a spring (not shown in the figure} ί ·5 I.' C can be associated with each of the walls for this purpose. As a modified embodiment, the walls can be released simply under gravity if, by design, their support spindle 29 is off-set relative to the periphery of the assembly formed by the objects to be picked up.

As described above, the walls 27 of the skirt 22 can also be rigid.

As a modified embodiment, they can more simply be elastically deformable.

The present invention is not limited, moreover, to the embodiments and methods of use which have been described and shown, but includes any modified embodiment and/or modified combination of their various elements.

It should be emphasised that the device 20 forming a barrier for mechanically securing the load to be picked up has a fundamentally different function from the perforated bottoms of the similar devices of the prior art. Although both cases involve mechanical holding of the objects towards the source of suction, in the prior art the passage areas for the air flow must be as small as possible in order to prevent stray leaks, whereas according to the invention, on the other hand, it is desired to increase these passage areas, advantageously to reach about 1002, while at the same time ensuring that the objects are held

Claims

Cl aims

2. A gripping process as claimed in Claim 1, characterised in that, when the load to be picked up comprises objects arranged in superposed layers with a spacer interposed between two successive layers, the suction source assures that both one of the layers and its underlying spacer are picked up.

3. A gripping device for picking up a load comprising a plurality of objects arranged in a layer, by the process as claimed in Claim 1 or Claim 2, of the kind employing a suction source, a suction hood and a lateral confining means which is adapted, at least in part, for covering the load to be picked up, which means is connected to a device which forms a barrier for mechanically holding-back the load to be picked up, characterised in that the device which forms a barrier for mechanically holding-back the load to be picked up is adapted to create the minimum pressure drop in the air flow towards the suction source.

4. A gripping device as claimed in Claim 3, characterised in that said lateral confining means is rigidly connected to the suction hood. 5. A gripping process as claimed in Claim 1, 05 substantially as herein described.

5. A gripping device as claimed in Claim 3, substantially as herein described. Dated this 11th day of January 1983 Dermot P Cummins & Co By: 264 Merrion Road, Dublin 4 Agent for the applicant (Λι-.ιΆί L t ί ίιί·LLf v F