Gripping head

The present invention concerns a gripping head for packages of a wedge-like form. The invention also concerns a method of gripping a group of packages and transferring them into a box. The gripping head has side steering plates and pressure finger plates on two opposite sides. At one end of the gripping head a stop plate is arranged between the side steering plates and the pressure finger plates, while the opposite end is open. The side steering plates each has a number of steering plates and fingers of the pressure finger plates are placed on either side of the steering plates, which fingers are received in notches of the side steering plate. The fingers have folded lower ends. The side steering plates and the pressure finger plates are arranged mutually moveable bringing the folded lower ends of the fingers into and out of a position below the side steering plates.

TECHNICAL FIELD

The present invention concerns a gripping head for a group of containers or packages and a method of transferring a number of packages from a first position into a second position by means of the gripping head.

BACKGROUND OF THE INVENTION

It is common to place a number of filled containers or packages from a filling machine in some kind of box or the like for further transportation. The packages are to be placed orderly inside the box.

It is known to grip packages by means of suction cups, move the packages to a new position and then release the packages. Thus, the filled packages may be placed in a box or the like by means of the suction cups. It is also known to use a mat having a number of small openings, and which mat is set under vacuum to grip packages. Some packages have a straw attached to one side of the package, which straw is to be removed and used while drinking. The known gripping means does not always work well with packages having straws.

SUMMARY

The present invention has been developed for use with packages of a wedge-like appearance and to function well also with packages having straws attached to them. A person skilled in the art realizes that the gripping head of the present invention could be adapted for use with packages of many different appearances.

One object of the present invention is to bring a number or group of packages together and then lift them as one unit and place them in a box. One further object is to position the group of packages in a correct position to be placed in the box. A further object is to provide a suitable means to grip and lift the group of packages.

The above objects are met by a gripping head comprising side steering plates and pressure finger plates on two opposite sides of the gripping head. The side steering plates and pressure finger plates are moved towards and away from each other to grip, move and release the group of packages. The gripping head transfers one group of packages at the time to the box, until the box is filled. Each group of packages normally forms one layer in the box.

By means of the gripping head of the present invention it is possible to transfer the packages to the box in a safe way, without dropping the packages. Furthermore, the gripping head of the present invention has low running and maintenance costs.

Further objects and advantages of the present invention will be obvious to a person skilled in the art reading the detailed description below of different embodiments.

DETAILED DESCRIPTION OF DIFFERENT EMBODIMENTS

As used in this description the expressions “upper”, “lower”, “vertical”, “horizontal” and similar expressions are in view of the gripping head as showed in the enclosed drawings.

On opposite sides of the gripping head of the present invention a side steering plate1and a pressure finger plate2are placed on each of said opposite sides. The side steering plate1has a number of steering plates3placed between fingers4of the pressure finger plate2. The side steering plate1and pressure finger plate2at each side of the gripping head are placed together and interconnected. The side steering plate1and the pressure finger plate2at each side are generally placed in a common vertical plane. The fingers4of each pressure finger plate2are received in notches17of the side steering plate1arranged in connection with the pressure finger plate2in question. When the steering plate1is provided with notches17for receiving the fingers4of the pressure finger plate2, such that the fingers4may pivot in the vertical plane around a horizontally arranged shaft6, in between the steering plates3, due to notches corresponding to the steering plates3in the pressure finger plate2, pressure inwardly may to a greater extent be transferred to packages8, thereby increasing friction between the fingers4and the packages thus increasing holding force.

At a first end of the gripping head a stop plate5is arranged between the ends of the opposite side steering plates1and pressure finger plates2. The stop plate5is arranged moveable on a rod11. The packages8received in the gripping head will act on the stop plate5to automatically place the stop plate5in the correct position. A mechanical stop is arranged on the rod11in order to limit the maximal turning angle of the stop plate5. The rod11may also be moved by means of cylinders and/or servo motors, which may be hydraulic, pneumatic or electric. A person skilled in the art realizes that the rod11may be driven in many different ways, but as this does not form any part of the present invention as such, it is not discussed in detail herein. By amending the position of the stop plate5either by rotation and/or by raising or lowering, the gripping head may be adapted to packages8having different forms.

At a second end of the gripping head opposite the stop plate5, the gripping head is open, to receive a group of packages8from a grouping position. Thus, the side steering plates1, the pressure finger plates2and the stop plate5has a U-form as seen in plan view. The group of packages8is normally brought into the gripping head by means of a conveyor belt. As indicated above normally the packages8will automatically place the stop plate5in a correct position as they are feed into the gripping head by means of the conveyor belt. The position of the stop plate5, in the case of wedge shaped packages as are seen inFIG. 5, is at a slight angle α (seeFIG. 6) such that the bottom and top edges of the packages are parallel with the side steering plates1and pressure finger plates2on opposite sides of the gripping head. Due to the packaging pattern, the stop plate will be switched to a corresponding angle α in the opposite direction for every layer, as the first package is always turned 180 degrees in relation to the first package in the previous layer.

The side steering plates1and pressure finger plates2are arranged movable. The side steering plate1and pressure finger plate2placed at one side of the gripping head are arranged mutually moveable. The fingers4may be turned away from the steering plates3in that the pressure finger plate2is turned by means of a cylinder7around the shaft6, arranged at the upper end of the pressure finger plate2.

Each side steering plate1has a number of steering plates3, which steering plates3are to make contact with base ends12of the packages8. In the shown embodiment each side steering plate1has three steering plates3. Fingers4of the pressure finger plate2extend downwardly on both sides of each steering plate3and are received in notches17of the side steering plate1. Thus, in the shown embodiment there are four fingers4and four corresponding notches17of the side steering plate1. The steering plate1also extends outside the outermost fingers4. At the lower end each finger4has an end10folded inwards. The folded end10of each finger4is directed towards the centre of the gripping head and will be placed below the lower end of the steering plates3. The folded ends10are generally horizontal. The folded lower ends10of the fingers4are placed below the packages8in a gripping position. When the steering plate1is provided with notches17for receiving the fingers4of the pressure finger plate2, such that the fingers4may pivot in the vertical plane around the horizontally arranged shaft6, in between the steering plates3, due to notches corresponding to the steering plates3in the pressure finger plate2, the folded ends10of the fingers4may be kept relatively short, while still obtaining satisfactory holding force, since they do not need to extend beneath the steering plate1. This structural feature also brings about the technical effect of eliminating the need of significant lateral movement of the finger plate2laterally beyond the steering plate1. Instead, the lateral pivoting movement of the fingers4may be kept within the width of the steering plate1, whereby basically only the steering plate1laterally limits vertical movement of the gripping head into spaces or boxes. Thus, packages8may be released from gripping action from the gripping head close to the surface of their intended position after movement, even in narrow boxes, thus minimizing the risk of damaging the packages8or their contents.

The side steering plates1, pressure finger plates2and the stop plate5of each gripping head are arranged moveable by means of cylinders7, for example around shafts6. Often the cylinders are pneumatically driven. However, a person skilled in the art realises that the different plates1,2,5of the gripping head may be arranged moveable by many different methods, such as pneumatic, hydraulic or electric. As the means of driving as such does not form any part of the present invention it will not be extensively described here.

The gripping head of the present invention grips a unit or group of several packages8. The gripping head of the invention has been developed with wedge like packages8in mind. In side view each package8has a base end12, from the base end12two sides13,14slope towards each other and form an apex15at the end opposite the base end12. In the shown embodiment the width of the packages8are smaller at an end16of the apex15than at the base end12, as seen in plan view.

In the units of packages8transported into the gripping head, every second package8is turned 180° in relation to the adjacent packages8of each unit of packages8. Thus, the end16of the apex15of one package8is placed adjacent the base ends12of packages8placed beside it.

Each unit of packages8forms one layer in a box (not shown) in which the gripping head is to place the packages8. The packages8are placed in the box with every second package8turned 180° in relation to the packages8placed above and/or below it, whereby the apex15of one package8is placed adjacent the base end12of the package placed above and/or below it. For a unit of packages8placed on a plane surface the base end12of each package8will be inclined. As indicated above a second unit of packages8is placed on the first unit of packages8, with the packages8turned 180° in relation to the packages of the first unit, whereby the upper side of the combined two layers of packages8will be relatively plane (SeeFIG. 5.). When transferring a first set of wedge like packages8to secondary packages, it is especially important to release the packages8on the bottom or at least close to the bottom of the secondary package, since the wedge like shape of such packages otherwise will render the packages out of relative order, whereby further arrangement of a second set of packages8on top of the first set will be severely hampered. Instead, the disorder will be further increased when transferring the second set. This will adversely affect the packing efficiency in terms of the volume needed (occupied) for a specific number of packages. With the present invention it is possible to minimize the size of the secondary package.

The sides9of each steering plate3, facing inwards in the gripping head, i.e. abutting packages inside the gripping head, slopes in the same extent as the base end12of a package8placed on a surface. Thereby it will be full contact between the sloping sides9of the steering plate3and the base end12of a package8. The inclined contact area between the steering plates3and the packages8facilitates the release of the packages8.

In use a number of packages8are transported as a group or unit from a grouping position into the gripping head, normally by means of a conveyor belt. The unit of packages8are feed into the gripping head at the open end opposite the stop plate5. As stated above each package8is turned 180° in relation to the packages8placed on either side of it. At this time the side steering plates1and the pressure finger plates2are at an outer position or first, open position. The unit of packages8are transported until they abut against the stop plate5. When the unit of packages8has reached the stop plate5, the side steering plates1and the pressure finger plates2are moved inwardly to a second, closed position. In said closed position the steering plates3will about against base ends12of the packages8. By means of the steering plates3the packages8are brought to the desired positions for later placement in the box. At the same time the fingers4of the pressure finger plates2will be pressed against the packages8. The folded ends10of the fingers4are placed under the packages8in this position. Thus, the packages8will be held in the gripping head in this position by means of the steering plates3abutting the packages8, the fingers4pressed against the packages8and the folded ends10of the fingers4placed below the packages8.

The gripping head is then moved into a box, with the unit of packages8firmly held. Thereafter the fingers4are turned into an open, release position, in which the fingers4are no longer pressed against the packages8and the folded ends10of the fingers4no longer are placed below the packages8. The steering plates3will still abut the packages8. Finally the gripping head is lifted from the box, whereby the steering plates3leave the abutment against the packages8. Thanks to the inclined contact surface between the steering plates3and the packages8, the contact will be broken quickly, and as the folded ends10of the fingers4are displaced from under the packages8, the packages8will remain orderly placed inside the box when the gripping head is lifted.

The gripping head is then moved to receive a new unit of packages8transported from the grouping position. The side steering plate1and the pressure finger plate2are brought to the first, open position before the new unit of packages are received from the grouping position.

In one embodiment the box is placed directly below the gripping head. When the packages8have been gripped by the gripping head, the conveyor belt transporting the packages8into the gripping head is turned away or retracted. With the conveyor belt out of the way, the gripping head holding a unit of packages8is lowered into the box and the packages8are released. Then the gripping head goes up again into position for receiving a new unit of packages8and the conveyor belt goes back into position for delivering the next unit of packages8. A person skilled in the art realizes that the movement of the gripping head into the box receiving the packages may be arranged in many different ways.

The gripping head will continue to move groups of packages8to the box until the box have been filed. Then the filled box is replaced with an empty box to be filled by means of the gripping head of the present invention.