NL1017872C2 - Method and device for forming uniform stacks of uneven, substantially flat objects. - Google Patents

Abstract

The invention relates to a method for forming uniform stacks (2) of unequal flat objects.(3) The method comprises the steps of feeding the objects, stacking the supplied objects onto each other in two equal part-stacks, transporting the part-stacks to a combining location and combining the part-stacks into a uniform stack at this location, wherein during the transport one of the part-stacks is separated off, rotated through a determined angle and once again transported further. The invention also relates to an apparatus (1)for performing the method, comprising means (4) for feeding the objects,(3) means (5) for stacking the supplied objects onto each other in two equal part-stacks, means (16) for transporting the part-stacks to a combining location, means (7, 20) for combining the part-stacks into a uniform stack (2) at this location, and means (7) arranged between the first stacking means and the combining location for separating one of the part-stacks from the transport means, rotating said part-stack through a determined angle and feeding said part-stack back again to the transport means.

Description

METHOD AND APPARATUS FOR FORMING EQUIVALENT STACKS OF UNRIVALED, PRINCIPALLY FLAT OBJECTS

The invention relates to a method for forming uniform stacks of uneven, substantially flat objects and to a device for performing this method.

Various methods and devices are already known for forming uniform stacks of flat objects that do not have the same thickness over their entire surface, such as, for example, folded packaging boxes. The formation of such uniform stacks is important when these packaging boxes must be packaged in an outer package when folded or bundled in stacks, for example for delivery to an end user.

US-A-3 970 202 discloses a device for forming uniform stacks of such objects. This known device is provided with a conveyor belt that can be rotated about a horizontal axis between two positions. In each of these positions, the belt 20 ends up in a stacking location. The device is further provided with a gripping mechanism with an arm pivotable about a horizontal axis. This mechanism picks up a stack from one stacking location and brings it with a pivotal movement through 180 ° to the other stacking location, where the two oppositely directed stacks are combined into a single, uniform stack.

For the same purpose, US-A-4 264 255 describes a device with a conveyor belt leading to a first stacking location. This stacking location is provided with a removable bottom, so that a stack can sink to a second stacking location located below. This second stacking location can be rotated through 180 ° around a 2 vertical axis. After the stack has been rotated at the second stacking location, a second stack can be lowered from the first stacking location onto the rotated first stack, whereby a uniform stack is also formed.

With a similar device as known from US-A-4 474 521 the supply belt ends at a single stacking location, from here the stacks are picked up by grippers which are suspended from an endless conveyor. This conveyor brings the grippers with the stacks therein to a location where two stacks are combined into a single stack.

The grippers are alternately rotated 180 ° and not rotated during transport, so that successive 15 stacks are each directed in the opposite direction.

US-A-5 078 260 describes a device in which two separate conveyors are provided from the supply belt, each of which traverses a curved path. The paths of the conveyors are thereby chosen such that the objects running through one path are turned through 180 ° with respect to the objects in the other path. The two conveyor tracks end up in juxtaposed stackers, the two stacks of which are directly assembled into a single, uniform stack.

Finally, from US-A-5 396 752, another device is known in which stacks are formed on the input side, which are subsequently transported between two conveyor belts. A section of the two conveyor belts is herein incorporated in a frame that can be tilted about an axis that is parallel to the transport direction. By alternately rotating the frame with the conveyor belts and not rotating them through 180 °, successive stacks are directed in opposite directions. After transport, these oppositely oriented stacks are combined into a single, uniform stack.

The invention now has for its object to improve the existing ways of forming uniform stacks on the basis 3 of flat objects of uneven thickness. A stack here is not only understood to mean a vertical stack of horizontally oriented objects, but also a horizontal stack of objects standing upright next to each other.

According to a first aspect, the invention provides for this purpose a method for forming uniform stacks of uneven, substantially flat objects, comprising the steps of supplying the objects, stacking the supplied products onto each other up to at least two substantially identical sub-stacks objects, transporting the sub-stacks to a joining location and joining the sub-stacks to a uniform stack at that location, wherein during transport at least one of the sub-stacks is separated, is rotated through a certain angle and is transported again: Because the sub-stack to be rotated is separated during transport, the rotation movement can be carried out in a simple manner, while not much space needs to be kept free for this purpose. In addition, the cycle time is thus hardly influenced by the rotational movement.

The at least one sub-stack can be rotated about an axis that is substantially parallel to the main surface of the stacked objects, whereby the sub-stack thus comes to lie outside with a different side. It is additionally or alternatively also possible for the at least one sub-stack to be rotated about an axis that is substantially perpendicular to the main surface of the stacked objects. Thus, the same side of the stack remains outside.

In order to orient the objects in opposite directions, the at least one sub-stack is preferably rotated through an angle of substantially 180 °.

Advantageously, the sub-stacks are substantially enclosed on all sides during the various steps. In this way it is ensured that well-oriented stacks are formed under all 4 conditions, which can simply be further processed, for example placed in an outer package or bundled.

An extremely simple to carry out method, which does not extend the cycle time at all, is obtained when the transport of the sub-stacks proceeds stepwise, and the separation and rotation of the at least one sub-stack takes place between two steps.

According to a second aspect of the invention, a device is provided for forming uniform stacks of uneven, substantially flat objects, comprising means for supplying the objects, means for stacking on each other up to at least two substantially equal sub-stacks of The supplied objects, means for transporting the sub-stacks to a joining location, means for joining the sub-stacks to a uniform stack at that location, and means for separating from the transport means arranged between the first stacking means and the joining location rotate a certain angle and return it to the conveying means of at least one of the sub-stacks. Such a device is efficient, has a high capacity and requires only a small floor area.

A particularly compact and efficient device is obtained when the separating and rotating means are integrated with the joining means.

In order to be able to rotate the objects in a controlled manner, the separating and rotating means preferably comprise at least one engaging member for the at least one sub-stack. In order to be able to create space for the rotational movement, the at least one engaging member is advantageously movable substantially transversely of the conveying direction.

The at least one engaging member can herein be rotatable about an axis that is substantially parallel to the main surface of the stacked objects and / or about an axis that is substantially perpendicular to the main surface of the stacked objects. The objects can thus be subjected to 5 different rotational movements.

For collecting and collecting the supplied objects on a stack, the first stacking means preferably comprise at least one carrier member which is movable substantially transversely to the direction of transport. This at least one support member is advantageously movable in a first direction for forming the sub-stacks, and in a second direction for transferring the formed sub-stacks to the transport means.

For transferring a series of objects from the supply means to the first stacking means. there are advantageously provided at least one movable separating member cooperating with the supply means, to be introduced into the path of the supplied objects.

The device can further be advantageously provided with means for discharging the formed, uniform stacks, which discharge means, like the first stacking means, comprise at least one carrier member which is movable substantially transversely to the conveying direction.

In order to form optimally uniform stacks with straight sides, the first stacking means, the transport means, the separating and rotating means and / or the joining means are preferably adapted to substantially enclose the sub-stacks on all sides. To that end, for example, the transport means can comprise a conveyor guided between walls with projecting carriers.

The invention will now be explained with reference to an example, with reference to the accompanying drawing, in which: 1 shows a partly cut-away perspective view of a stacking device according to the invention, and 6

FIG. 2 shows a detail of the separating and rotating means according to the arrow II in FIG. 1.

A device 1 (fig. 1) according to the invention for forming uniform stacks 2 of substantially flat objects 3, the thickness of which is not the same over the entire surface, comprises supply means 4, first stacking means 5 connecting thereto, with the first stacking means conveying means 6 placed in series, separating and rotating means 7 arranged along the conveying means 10 and adjoining discharge means 8. The separating and rotating means 7 thereby also function as combining means 20, as will be explained below. The objects 3 of uneven thickness are, for example, folded packaging boxes, which have a greater thickness in places where, for example, parts of the bottom or bottom side are folded in the package, or side panels overlapping at each other.

The supply means 4 are formed by a number of parallel, endless belts 9 which are wrapped around return rollers (not shown here) and are driven by a (not shown here) drive motor. A number of objects 3 are staggered on these belts 9, i.e. partially overlapped. For example, a counter (not shown here) is placed above the supply means 4, which counter emits a signal when a certain amount of objects 3 has passed. This signal activates a separator (not shown here), for example a number of fingers protruding between the belts 9. These separation fingers are connected to their own drive, as a result of which they are moved in the direction of the first stacking means 5, taking the counted series of objects 3 into account. Thus, a predetermined number of objects 3 is transferred to the stacking means 5.

Instead of a counter, it is also possible to use a detection device which detects an ejected object, that is to say located outside the scale. This object 3 could then be pressed out of the scale in a previous machine, such as a folding / pasting machine, as a marking of a certain number of objects. The counting then takes place in the previous 5 machine.

The stacking means 5 are formed by a support member 10, here a fork, which is movable in the stacking direction by means of a drive (not shown here). In the example shown, the fork 10 is movable in height direction along a rear plate 13, for forming a standing (sub) stack of horizontally oriented objects 3, but it is also conceivable that the support member 10 moves away from the supply belts 9 in the horizontal direction. could be moved, to form a horizontal (sub) stack, when the objects 3 were supplied vertically, i.e. standing on one side.

In the starting position shown, the teeth 11 of the fork 10 are at substantially the same level as the supply belts 9, or slightly below. Each time a package 3 is slid onto the fork 10, it drops one step, so that the upper side of the upper package 3 on the fork 10 then becomes level with the supply belts 9. This is continued until the last package of the the series formed by the separating fingers is slid onto the fork 10, whereafter it is moved further down until the sub-stack 12 formed thereon rests on the transport means 6. The fork 10 with the rear plate 13 is then pulled by means of a drive (not shown here) over a guide 14 from the path of the transport means 6.

The transporting means 6 comprise a conveyor, which is formed by two endless belts or chains 15, which are passed over two pairs of return rollers or chain wheels 16. The conveyor is driven by a motor (not shown here) in a stepwise fashion determined by the first stacking means 5 and / or the separating and rotating means 7 to be discussed hereinafter. Relatively long carriers 17 are attached to each belt or chain 15 , the length of which approximately corresponds to the height of the (sub) stacks 2 or 12 to be transported.

By making use of two belts or chains 15, which are adjustable relative to each other, the mutual distance of the carriers 17 can be adjusted to the size of the objects to be transported. 3. Also, the carriers 17 can thus be positioned correctly. be placed relative to the supply means 4.

The carriers 17 move through a central slot 18 in a U-shaped guide box 19, which is formed by two L-shaped segments, which define bottom parts and side walls of the guide box 19. The mutual distance of the carriers 17 and of the side walls of the guide trough 19 are chosen such that the (sub) stacks 12 are almost completely enclosed, and thus kept purely vertical. This mutual distance can be adjustable if it is desired to make the stacking device 1 suitable for processing objects 3 of varying dimensions. The side walls of the guide trough 19 extend over almost the entire transport path of the (sub) stacks, and are only interrupted at the location of moving parts, such as the fork 10.

The conveyor carries the sub-stacks 12 to a station 20 with the separating and rotating means 7 and the joining means 20 integrated therewith, where each second sub-stack 12 is received and turned. The separating, and rotating and joining means 7,20 comprise a bridge 21, on which two grippers 22 are suspended with the aid of supports 23. The supports 23 with the grippers 22 are movable in the horizontal direction, transversely of the conveying direction, so that the grippers 22 can grasp a partial stack 12 on the conveyor and release it again. To that end, the grippers 22 comprise claws 26 which are movable towards and away from each other and which are connected to a support plate 27.

9

The bridge 21 with the grippers 22 is furthermore movable transversely to the direction of transport, here in the vertical direction. To this end, the bridge 21 is suspended from a support 24, which can be slid up and down along guides 25 along a guide 25 (not shown here). In the raised state there is sufficient space to turn a sub-stack 12 clamped in the grippers 22. In the example shown, this turning can take place in two different ways.

Firstly, the grippers 22 are rotatably mounted in the supports 23 about a horizontal axis 28, so that the sub-stack 12 can therefore be turned upside down. This is a useful movement when, for example, it is desired that the back side of the outer object 3 on both sides of the final stack 2 is directed outwards, for example in connection with possible damage.

In addition, the bridge 21 is suspended from the support 24 with the aid of a pivot bearing 29, 20, so that the sub-stack 12 can also be rotated parallel to the conveying direction. This rotational movement can be important when it is desirable that the objects 3 in the final stack 2 are all facing the same side.

After turning the sub-stack 12, the bridge 21 with the grippers 22 can be kept in the pushed-up state until the conveyor has guided a subsequent sub-stack 12 to the separating and rotating means 7. The bridge 21 can then be lowered, wherein the turned sub-stack 12 is placed on the correctly supplied sub-stack 12 to form a uniform stack 2. The separating and rotating means 7 thus also function as joining means 20.

The combined stack 2 can then be further transported to an end station 30, where the discharge means 8 are located, which are formed by two supporting members 31 which are movable transversely to the conveying direction. Each supporting member 31 is thereby formed by an L-shaped segment, which connects to the guide trough 19, and which is movable up and down along guides 32 by a drive (not shown here). In the pushed-up position, the underside of the support members 31 and of the stack 2 are at the level of a discharge conveyor 33. A push member 35 movable along guides 34 parallel to the conveying direction slides the stack 2 from that position onto the discharge conveyor 33. A binding device 36 is also present in the example shown, as a result of which one or more binding members can wrap around the stack 2 turn into.

Incidentally, it is also possible for the discharge means 8 to function as additional combining means. In that case the turned-over stack 12 is replaced by the bridge 21 with grippers 22 on the transport means 6 between the same carriers 17 through which it was supplied, whereafter the transport means 6 are moved again by one step. The sub-stack 12 which after this step lies under the bridge 21 with grippers 22 is not picked up. Ultimately, alternating and non-turned sub-stacks 12 are supplied to the end station 30. There, the support members 31 are first moved upwards over the height of a sub-stack 12, whereafter they are taken over by a retractable or collapsible support (not shown here). The support members 30 are then lowered again, the next sub-stack 12 is supplied thereon, and then this sub-stack is also picked up and moved up. By then withdrawing or folding the support, the two sub-stacks 12 are combined to form a stack 2.

Incidentally, both the separating and rotating means 7 and the discharging means 8 could simultaneously act as joining means, so that multiples of two sub-stacks 12 in each case could then be merged into a single stack 2.

The stacking device 1 according to the present invention thus makes it possible to form uniform stacks 2 of uneven objects 3 in a fast and reliable manner. The capacity of the device 1 is thereby large, while it also occupies a limited floor area. Moreover, the (sub) stacks 5 are properly guided and retained at each processing step, whereby a very regular end product is obtained.

Although the invention has been explained above with reference to an example, it will be clear that it can be modified and varied in many ways. For example, the separating and rotating means 7 could be adapted to perform a movement about only a single axis, instead of the two axes shown. The rotation could even be omitted when a supply of completely flat objects 3 is offered.

The rotation movement could also be carried out through a different angle than the 180 ° angle shown. For example, it is conceivable to merge four sub-stacks 12 into a single stack 2, each sub-stack then being rotated through 90 ° with respect to its adjacent sub-stacks when the bulge is only in one corner of the object 3. It is also possible to rotate the sub-stack 12 only through 90 ° about the horizontal axis 28, as a result of which the originally vertically oriented sub-stacks 12 could be merged into a horizontal end stack 2.

Furthermore, the shape of the different conveyors and the manner of driving the different movable parts can of course be chosen freely, depending on the desired application.

The scope of the invention is therefore solely determined by the appended claims.

Claims (19)

Method for forming uniform stacks of uneven, substantially flat objects, comprising the steps of feeding the objects, stacking the supplied objects onto each other up to at least two substantially equal sub-stacks, transporting them to a joining location of the sub-stacks and joining the sub-stacks to a uniform stack at that location, wherein during transport at least one of the sub-stacks is separated, rotated through a certain angle and transported again. 2. Method according to claim 1, characterized in that the at least one sub-stack is rotated about an axis that is substantially parallel to the main surface of the stacked objects. Method according to claim 1 or 2, characterized in that the at least one sub-stack is rotated about an axis that is substantially perpendicular to the main surface of the stacked objects. Method according to one of the preceding claims, characterized in that the at least one sub-stack is rotated through an angle of substantially 180 °. 5. Method as claimed in any of the foregoing claims, characterized in that during the different steps the sub-stacks are substantially enclosed on all sides. 6. Method as claimed in any of the foregoing claims, characterized in that the transport of the sub-stacks proceeds stepwise, and the separation and rotation of the at least one sub-stack takes place between two steps. 7. Device for forming uniform stacks of uneven, substantially flat objects, comprising means for supplying the objects, means for stacking the supplied objects onto each other up to at least two substantially identical sub-stacks, means for moving towards transporting the sub-stacks at a joining location, means for joining the sub-stacks to a uniform stack at that location, and means provided for separating from the transport means arranged between the first stacking means and the joining location, rotating over a determined angle and again to the transport means return of at least one of the 10 sub-stacks. Device as claimed in claim 7, characterized in that the separating and rotating means are integrated with the joining means. 9. Device as claimed in claim 7 or 8, characterized in that the separating and rotating means comprise at least one engaging member for the at least one sub-stack. Device as claimed in claim 9, characterized in that the at least one engaging member is movable substantially transversely of the conveying direction. Device as claimed in claim 9 or 10, characterized in that the at least one engaging member is rotatable. 12. Device as claimed in claim 11, characterized in that the at least one engaging member is rotatable about an axis which is substantially parallel to the main surface of the stacked objects. Device as claimed in claim 11 or 12, characterized in that the at least one engaging member 30 is rotatable about an axis which is substantially perpendicular to the main surface of the stacked objects. Device as claimed in any of the claims 7 to 13, characterized in that the first stacking means comprise at least one carrier member which is movable substantially transversely to the conveying direction. Device as claimed in claim 14, characterized in that the at least one support member is movable in a first direction for forming the sub-stacks, and is movable in a second direction for transferring the formed sub-stacks to the transport means. Device as claimed in any of the claims 7-15, characterized by at least one movable separating member cooperating with the supply means and to be introduced into the path of the objects supplied. 17. Device as claimed in any of the claims 7 to 16, characterized by means for discharging the uniform stacks formed, which discharge means comprise at least one support member which is movable substantially transversely of the conveying direction. 18. Device as claimed in any of the claims 7 to 17, characterized in that the first stacking means, the transporting means, the separating and rotating means and / or the joining means are arranged for substantially all-round enclosing of the partial stacks. 19. Device as claimed in claim 18, characterized in that the transport means comprise a conveyor guided between walls 20 with protruding carriers.