The present invention relates to a method for moving a stackable cargo unit from a first location to a second location using a device for engaging the stackable cargo unit, wherein the said device comprises a frame provided with a head that can be adjusted in height, which head comprises

- at least one head unit having a proximal end and a distal end, wherein the distal end is provided with a suction cup connected to a source of vacuum, and

- at least one actuator for moving the suction cup between a first position and a second position;

wherein the method comprises the following steps

- moving the suction cup from the first position to the second position,

- engaging the cargo unit with the suction cup,

- putting the cargo unit on a bearing surface in a condition in which the cargo unit is engaged by the suction cup and

- moving the cargo unit that is situated on the bearing surface.

Moving cargo units can be a laborious task. By way of example, the unloading of stackable cargo units from a cargo space such as a cargo space of a truck or sea container could be considered. To make this heavy work easier, a device of the above-mentioned type is known from for instance PCT/NL2013/050869 (WO2014/088415 ) . This device comprises a frame that is provided with a head at a first end, wherein during unloading the cargo from the cargo space at least a first end of the frame can be introduced into the cargo space for engaging the cargo units. Mostly, the stackable cargo units are boxes. Usually, their h x w x 1 dimensions are between 15 and 80 cm. Use of the device enables carrying the weight of the stackable loading units, as a result of which staff is physically burdened less or even unburdened entirely and able to work faster. Furthermore, a device provided with a plurality of suctions cups makes it possible to engage more than one stackable cargo unit at a time. They are pulled onto the platform by means of the suction cups and pushed from the platform after having been moved.

A problem is that boxes sometimes come in the shape of a box including a lid. They cannot or not reliably be moved with the device, for instance because the lid tears .

The object of the present invention is to provide a solution to this .

To this end, a method according to the preamble is characterized in that

the suction cup can be moved in a first direction defined by the first and the second position, and wherein the device further comprises a member for engaging a lid of a box, which member, independent of the first suction cup, can be moved by means of a second actuator in a second direction with a directional component that is transverse to the horizontal, between a third position and a fourth position;

wherein for moving a box that comprises a bottom part and a lid as the stackable cargo unit, the method comprises the steps of

- bringing the member into contact with the lid of the box,

- moving the member from the third position to the fourth position, and

- the step of engaging the cargo unit with the suction cup comprises engaging the bottom part of the cargo unit with the suction cup.

According to the invention, the lid is lifted and/or tilted to such an extent that the suction cup is able to engage onto the bottom part. The cargo unit, while being engaged by the suction cup, is then put on the bearing surface. This can be done by putting the bearing surface underneath the bottom part of the cargo unit and/or by pulling the cargo unit onto the bearing surface. Advantageously, once the cargo unit has been placed on the bearing surface, the lid is put back in its original position by taking the second suction cup from the fourth position to the third position. This can for instance be done if the member is designed like a driven wheel, by rotating the wheel into the opposite direction.

The bearing surface may be a passive or active bearing surface.

It may for instance simply have the shape of a plate, but also have the shape of a conveyor belt that may or may not be driven or a surface provided with rollers that may or may not be driven.

The lid may be a hinging lid of the box or a detachable lid. A lid comprises a topside section and lid wall sections extending downwards along at least a part of the top side section circumference. The bottom part comprises a bottom and wall sections extending upwards along the circumference. The lid wall sections surround the upwardly extending wall sections of the bottom part.

In the method according to the invention it will usually be avoided that the lid no longer entirely surrounds the bottom part, meaning that it will not be lifted entirely away from the bottom part. That way the lid can easily be put back in its original place.

According to an especially preferred embodiment, the device comprises a platform for supporting the stackable cargo unit in the first position, which provides the bearing surface;

wherein

- the step of putting the cargo unit on a bearing surface using the suction cup by taking the suction cup from the second position to the first position comprises putting the cargo unit on the platform, and

- the step of moving the cargo unit comprises moving the platform; after which the cargo unit is discharged from the platform.

By having the platform slide out, the forces exerted on the engaged wall of the bottom part, which forces might be able to tear the bottom part up, can be reduced. A box is better at withstanding the forces when it is lifted by the wall than when the wall is being pulled at .

According to a favourable embodiment, the member can be moved in a direction parallel to the first direction independent of the suction cup;

wherein

- the step of bringing the member into contact with the lid of the box, comprises taking the member to the box, wherein the member extends ahead of the suction cup,

- after the step of moving the member from the third position to the fourth position, the step of engaging the bottom part of the cargo unit using the suction cup is carried out.

In that way the lid can be lifted and/or tilted by the suction cup without being hindered. If so desired, the vacuum on the suction cup can only be applied once the member has been moved.

Finally, the present invention relates to a device for picking up and retaining the stackable cargo unit, wherein the said device comprises a frame provided with a head that can be adjusted in height, which head comprises

- at least one head unit having a proximal end and a distal end, wherein the distal end is provided with a suction cup configured for connection to a source of vacuum, and

- at least one actuator for moving the suction cup between a first position and a second position;

wherein the suction cup can be moved transverse to the vertical in a first direction defined by the first and the second position, and wherein the device further comprises a member for engaging the lid, which member, independent of the suction cup, can be moved by means of a second actuator in a second direction with a directional component that is transverse to the horizontal, between a third position and a fourth position.

Such a device is suitable to be used in the method according to the invention.

Preferably, the device comprises a vacuum pump for providing underpressure in the suction cup.

According to a favourable embodiment,

- the suction cup is a first suction cup, and

- the member has the configuration of a second suction cup, which second suction cup is configured to be connected to a source of vacuum .

This exemplary embodiment has the advantage that the location (height) of the lower edge of the lid does not need to be known exactly. The method is reliable over a lid height sufficient for providing room for the second suction cup.

Advantageously, the pressure in the second suction cup is measured, wherein a drop of air pressure in the second suction cup means that the lid has been engaged.

The cargo unit, while being engaged by the first suction cup, is then put on the bearing surface. The second suction cup may optionally assist in putting the cargo unit onto the bearing surface when the first suction cup is taken from the second position to the first position, but it is preferred that the box is not being horizontally pulled at. Advantageously, once the cargo unit has been placed on the bearing surface, the lid is put back in its original position by taking the second suction cup from the fourth position to the third position .

The source of vacuum, such as a vacuum pump, advantageously is the same as the one used for the first suction cup. Lines to a suction cup will be self-closing, to bound sucking in excessive quantities of false air and minimize the risk that a suction cup that is not used or does not connect properly, disrupts the method.

According to a favourable embodiment, the suction cup is mounted to a first end of a first elongated guide part, which first elongated guide part cooperates with a first guide body, and a spring is provided between the suction cup and the first guide body for exerting a force on the suction cup away from the first guide body.

In that way it is achieved that if a box is situated closer to the head than expected, the elongated guide part provided with the suction cup is pushed back, wherein the spring is pushed in and the box is not damaged.

For lifting the suction cup, the first guide body is preferably mounted so as to move transverse to the horizontal.

According to a favourable embodiment, the first elongated guide part is provided with a first stop at a second end, and the head unit comprises a third guide body that cooperates with the first elongated guide part for guiding the first elongated guide part relative to the third guide body, wherein without the suction cup contacting an object, the spring presses the first stop against the third guide body, and wherein the third guide body can be moved in the first direction .

In case of too firm a contact between the suction cup and the box, the stop will be released from the third guide body and the risk of damaging the box and/or its contents is minimized.

The actuator for moving the suction cup from the first to the second position (vice versa) does so by moving the third guide body. The spring is so strong that it keeps the first stop against the third guide body, the first guide rod is pushed back by an object contacting the suction cup, wherein the spring is pushed in. The first guide body remains stationary during this step.

According to a favourable embodiment, the member is mounted to a first end of the second elongated guide part, which second elongated guide part cooperates with a second guide body, and a spring is provided between the member and the second guide body for exerting a force on the member away from the second guide body.

In that way it is achieved that if a box is situated closer to the head than expected, the guide provided with the member is pushed back, wherein the spring is pushed in and the box is not damaged.

According to a favourable embodiment, the first guide body is provided with a further guide for the second guide body, which further guide is transverse to the first elongated guide part.

In that way the height between the member and the suction cup can be efficiently changed, that is, in the second direction.

According to a favourable embodiment, the second elongated guide part is provided with a second stop at a second end, the third guide body cooperates with the second elongated guide part for guiding the second elongated guide part relative to the third guide body, wherein without the member contacting an object, the spring presses the second stop against the third guide body.

In case of too firm a contact between the member and the box, the stop will be released from the third guide body and the risk of damaging the box and/or its contents is minimized.

According to an especially preferred embodiment, the device comprises a platform for supporting the stackable cargo unit in the first position which provides the bearing surface, wherein both the suction cup and the member can be moved beyond the distal end.

By having the platform slide out, the forces exerted on the engaged wall of the bottom part, which forces might be able to tear the bottom part up, can be reduced. A box is better at withstanding the forces when it is lifted by the wall than when the wall is being pulled at .

According to a favourable embodiment, the suction cup can be moved transverse to the horizontal.

In that way the box can be put on the bearing surface with even less friction.

According to a favourable embodiment, the platform has a distal end, and at the distal end is provided with a wheel that can be rotated about a horizontal axis.

That way the box can be put on the platform with reduced

friction, as a result of which less force needs to be exerted on the box. In case of a relatively soft box, which may derive its strength from the combination of the lid and the bottom part, the risk of the box being torn is reduced.

The wheel preferably has the configuration of a roller.

Advantageously the top side of the wheel projects beyond the top side of the platform, but the wheel may even be situated slightly below the top side as the box is tilted by means of the suction cup and contact with the wheel is possible anyway for sliding the platform underneath the box without friction.

In actual practice the wheel will be part of the bearing surface. In many cases a box will be held up at one of its sides by the suction cup, whereas the bottom of the box rests on the wheel. By pulling the platform away from underneath the box, the box can be put down quickly and carefully, without having to exert pushing forces onto it.

The present invention will now be illustrated with reference to the drawing where

Fig. 1A shows a device for moving a stackable cargo unit;

Fig. IB shows an arm of the device according to Fig. 1A;

Fig. 1C to Fig. IE show a top view, a side view and a front view, respectively, of a head that is attached to the arm according to Fig. IB; and

Fig. 2A to Fig. 2J show the steps of moving a box in side view.

Fig. 1A shows a device 100 for moving a stackable cargo unit 190, or more commonly a number of stackable cargo units 190.

The device 100 comprises a frame 110 that is provided with an arm 120. At its proximal end 121, the arm 120 is attached to the frame 110 so as to be rotatable about a vertical axis.

The arm 120 is provided with a head assembly 140. The head assembly 140 is attached to a distal end 122 of the arm 120 so as to be rotatable about a vertical axis. In the art, such a device is known and needs no further elucidation.

The frame 110 is equipped with a vacuum pump 130 the roller of which will be elucidated below. A cable guide 101 contains electricity wires and vacuum lines to the head assembly 140.

Fig. IB shows the arm 120 of the device 100 according to Fig. 1A in more detail. The head assembly 140 comprises a head 150 which, along a first guide 141 comprising a rack, can hydraulically be adjusted in height relative to the distal end 122 of the arm 120, and in that way be taken to the level of a row of boxes 190 in order to move them, such as for instance may be the case when unloading a sea container .

The device 100 according to the invention is in particular also suitable if the stackable cargo unit is a box 190, which box comprises a bottom part 191 and a lid 192, as will be elucidated below.

Fig. 1C to Fig. IE show a top view, a side and a front view, respectively, of the head 150 of the head assembly 140 that is attached to the arm 120 (Fig. IB) of the device 100. The head 150 at least comprises a head unit 160, in this case six, which in this case by means of a spindle 157 can be adjusted in height independent of each other by means of second guides 151, which second guides 151 are provided on a rear plate 152 of a frame 155 of the head 150.

The frame 155 of the head 150 comprises a plate 153 that is electrically extendable by means of a geared belt, which plate at a distal end (remote from the rear plate 152) is provided with a roller 154. As will be explained below on the basis of Fig. 2, the extendable plate 153 will be slid underneath the box, wherein the roller 154 reduces the friction. In the extended position, the extendable plate 153 provides a bearing surface 156 when the box 190 rests on the head 150.

The head unit 160 comprises a suction cup 161 for engaging the bottom part 191, and a member 162 for engaging the lid 192, here in the configuration of two suction cups 162', 162".

The suction cups 161, 162 are connected to the vacuum pump 130 and are driven in a controlled manner by a control.

The suction cup 161 is mounted to a first tube 163 that is arranged in a first guide body 170 so as to be movable in a first direction transverse to the vertical, which first guide body 170 itself is connected to the frame 155 so as to be movable transverse to the extendable plate 153 by means of a guide 176 comprising a spindle. By means of a first spring 171 able to support against the first guide body 170, the suction cup 161 can be pushed away from the rear plate 152.

Likewise, the suction cups 162', 162" are mounted to second tubes 164, which second tubes 164, and consequently the second suction cups 162', 162" can be moved in the same direction as the first tube 163, that means parallel to the first direction. The second tubes 164 are mounted in a second guide body 172 so as to be movable, which guide body can be moved in a second direction transverse to the horizontal between a third position and a fourth position using the guide 176 that comprises a spindle. The second tubes 164 are also pushed away from the rear plate 152 by second springs 174 that support against the second guide body 172.

At the end of the first tube 163 opposite the suction cup 161, a first stop 166 is provided and at the end of the second tubes 164 second stops 167 are provided. The head unit 160 comprises a third guide body 173 which has a slot (not visible) through which the first tube and second tubes extend and which cannot pass by the stops 166, 167. The slot serves to make the movement of the second tubes 164 in a direction from the third position to the fourth position possible.

That way the head makes it possible to vertically and

horizontally move the second suction cups 162", 162' independent of the first suction cup 161, and allows for the first suction cup 161 to be able to move horizontally and vertically. In case of a vertical movement of the first guide body 170, the second guide body (and the third guide body, that always moves vertically along with the first guide body 170) will also move along vertically.

The third guide body 173 serves to move the tubes in a horizontal direction. This is done by, in this case electrically by means of spindle 175, allowing the third guide body 173 to move transverse to the rear plate 152 while using a third guide 175 that is fixedly connected to the first guide body 170. If a suction cup hits an object, the tube to which the suction cup is mounted allows for a movement of the tube relative to the guide members. The spring makes sure that the suction cup remains in contact with the object.

Fig. 2A to Fig. 2J show the steps of moving a box in side view.

Fig. 2A shows a head unit 160 in an initial position, wherein the suction cups 161, 162 and the roller 154 of the extendable plate 153 are situated relatively close to the rear plate 152.

The head 150 is taken to the level of the boxes 190 to be engaged. In principle, this takes place by allowing the head assembly 140 to move along the first guide 141. In the embodiment discussed here, the head units 160 can individually be varied in height using the spindle 157 (Fig. 2B) that is driven by a motor.

Subsequently the third guide body 173 is moved away from the rear plate 152 (Fig. 2C) by means of the third guide which comprises a spindle. By means of the springs 171, 174 the first tube 163 to which the first suction cup 161 is mounted and the second tubes 164 to which the second suction cups 162', 162" are mounted, also move away from the rear plate 152, until the second suction cups 162', 162" contact the lid 192 of the box 190. Using an underpressure that is provided by the vacuum pump 130, the lid 192 is engaged at a side of the box 190.

Subsequently the lid 192 is partially lifted, by moving the second guide body 172 upwards relative to the first guide body 170 (Fig. 2D)

Now that room has been provided for the lower suction cup 161, the bottom part 191 of the box 190 is subsequently engaged by the lower suction cup 161 (Fig. 2E) .

The box 190 is now slightly lifted at one side by moving the first guide body 170 upwards (Fig. 2F) , together with the second guide body 172 and the third guide body 173.

The extendable plate 153 is moved away from the rear plate 152 by means of a geared belt (Fig. 2G) , as a result of which the roller 154 contacts the bottom side of the box 190 and the box 190 is put on the extendable plate 153. The third guide body 173 is then also moved to the rear plate 152 (Fig. 2H) . The stop 167 hits the third guide body 173, as a result of which the first suction cup 161 is passed back in the direction of the rear plate 152 and takes along the box 190. The box 190 can now be moved.

The head unit 160 is lowered in height by means of the spindle 157, and the lid 192 is lowered relative to the bottom part 191 by lowering the second guide body 172 relative to the first guide body 170 (Fig. 21) . This can take place while moving the box 190. The underpressure in the second suction cups 162', 162" can be terminated.

Finally, the box 190 is discharged at a desired location by retracting the extendable plate 153 (Fig. 2J) , wherein the

underpressure in the first suction cups 161 is terminated.

Fig. 2H also shows flexible vacuum lines 230 connecting the vacuum pump 130 to the suction cups 161, 162. In this embodiment of the invention, the tubes 163 and 164 therefore have a double function, and the vacuum lines 230 are not in the way when using the device 100.

Some of the actuators 240 (motors 240) used for driving the various parts, are indicated using a reference number. Others are not properly visible due to the U-shaped bottom part of the frame 155. The actuator 240' for instance serves to move the first guide body 170, and as a consequence also the second guide body 172 and the third guide body 173, in the second direction via a transmission.