Patent ID: 12252361

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the invention with further developments described in the following are to be regarded only as examples and are in no way to limit the scope of the protection provided by the patent claims. The use of directional specifications, such as front, rear, up, down, forwards, etc., refers to the orientation of the stack of cartons. The bearing plane for the stack of cartons is in the shown example referred to as being horizontal, even if the bearing plane could be angled somewhat, by e.g. 10-20 degrees.

FIGS.1and2show views of a feeding device,FIGS.3to5show details of the feeding device, andFIG.6shows a flowchart of a method for feeding stacks of flat-folded cartons to a receiving station. The feeding device1according to the invention comprises a straight conveyor track30having a flat bearing plane3adapted to feed stacks of standing flat-folded cartons2from an infeed region32to an outfeed region13, where adjacent stacks conveyed by the feeding device are merged with each other to form a long continuous stack of flat-folded cartons. The carton stacks2are forwarded to a receiving station, e.g. a carton erecting machine, through an outfeed conveyor31via a sliding track14which bridges the conveyor track30and the outfeed conveyor31. The conveyor track comprises a plurality of protruding teeth17that will support the stacks of flat-folded cartons.

The conveyor track comprises at least two rows of teeth. In the shown example, the conveyor track comprises three rows of teeth, a first row of teeth5, a second row of teeth6and a third row of teeth7. The first row of teeth5is attached to a first conveyor chain8, the second row of teeth6is attached to a second conveyor chain9and the third row of teeth7is attached to a third conveyor chain10. The first, the second and the third conveyor chain are driven in parallel by the same drive unit11such that they move at the same speed, and such that the teeth positioned next to each other move at the same time. The teeth of each row of teeth are positioned side by side, such that three teeth arranged next to each other form a bearing plane perpendicular to the moving direction of the conveyor track.

The stacks of flat-folded cartons are inserted between the teeth at the infeed region. The stacks of flat-folded cartons are inserted between the teeth, either manually by an operator, or by a placing device, e.g. an industrial robot. The teeth are in the shown example slightly angled in a forward direction with respect to a vertical plane, such that the stack will bear against the bearing surface18of the teeth arranged next to each other. The teeth may also be perpendicular to the bearing plane or may be slightly angled in a rearward direction with respect to a vertical plane, depending on e.g. the type of used cartons. The stack of flat-folded cartons may expand when it has been inserted between the teeth, such that the stack of flat-folded cartons also bear against the pushing surfaces19of the following teeth.

The stacks of flat-folded cartons are conveyed to the outfeed region13, where the stacks will slide on a sliding track14when the conveyor track turns downwards to the return path. Following the sliding track is an outfeed conveyor31, e.g. a short belt conveyor, which actively transports the stacks to e.g. a carton erecting station. At the sliding track and the outfeed conveyor, the stacks of flat-folded cartons are merged to a continuous flow of flat-folded cartons (not shown). The speed of the conveyor track is e.g. adapted to the pick-up speed of cartons at the carton erecting station, such that the density of flat-folded cartons is approximately constant on the outfeed conveyor, and such that no extra buffer is required. It is e.g. possible to control the drive unit11of the feeding device with the pick-up speed of the carton erecting machine.

A tooth17is arranged on a pushing member16, shown inFIG.4. The pushing member is attached to a conveyor chain at a pivot point22, e.g. with a screw such that it is possible to replace the pushing member. The pushing member comprises a tooth17arranged on one side of the pivot point22, and a frame20arranged at the other side of the pivot point. The frame comprises a cover surface21. A roller23is mounted on the frame. The roller is adapted to hold the tooth in the selected position, and is adapted to run in a guide track24. The roller may comprise a slide bearing or a roller bearing.

A tooth17can be positioned in two positions, an erected position or a folded position. In the erected position, the tooth protrudes from the bearing plane of the conveyor track. In the folded position, the tooth is arranged below the bearing plane of the conveyor track, with the pushing surface19close to the bearing plane. In this position, the pushing surface will cover the area between two conveyor chains and the pivot points of two adjacent pushing members. This will cover the void created between the conveyor chains and will prevent e.g. a finger or other object to be caught in the conveyor track. When a tooth is erected, the cover surface21of the frame will cover this void. At the bearing plane, the roller will be guided in a guide track24arranged in parallel with the bearing plane3, and will securely hold the tooth either in the erected position or in the folded position.

At the end region15, shown inFIG.3, the guide track24ends, and the tooth is released from its predefined position. When the tooth is in the erected position, the tooth will continue with a slightly angled direction, and will be guided by the stacks of flat-folded cartons. The tooth will at the same time leave the bearing plane downwards in a substantially vertical orientation, and the stack of flat-folded cartons will join the previous stacks of flat-folded cartons at the sliding track14. The group of flat-folded cartons will be pushed forwards by the following teeth at the sliding track.

At the outfeed region, the conveyor track30runs on a drive wheel34to the return path. Here, the teeth are free-floating and the rollers are not controlled by a guide track. When the teeth reach the return path, all teeth are set to a predefined position, in the shown example to a folded position, where the pushing surface19bears against a slide rail35. At an intermediate position of the return path, all teeth are in the shown example erected to an erected state by an erecting member33, such that all teeth have the same orientation.

A switch25, shown inFIG.5, is arranged at the return path for each row of foldable teeth, where a switch comprises a switch cylinder26, a switch member27and an actuating tab28. The switch member is arranged at a pivot point29, around which the switch member can pivot when the cylinder extends or retracts. When the cylinder is retracted, the switch will be in an active state in which the actuating tab will extend into the path of the erected teeth. When the cylinder is extended, the switch will be in a passive state in which the actuating tab is pivoted away from the path of teeth. With the switch in the active state, the pushing surface19of a tooth will hit the actuating tab and will be pushed to a folded state. With the switch in the passive state, the tooth will continue in the erected state.

In this way, the state of each tooth can be controlled by the switches. The distance between two erected teeth can be set to the length of a stack of flat-folded cartons. In the example shown inFIG.1, the longitudinal distance between each tooth is e.g. 100 mm. By positioning every second tooth in an erected position, the feeding device will be adapted to handle stacks of flat-folded cartons having a length of 200 mm. In this way, the feeding device can be adapted to several different stacks of flat-folded cartons having different lengths. It is e.g. possible to use the feeding device for stacks of flat-folded cartons of the five panel type, where a stack is 100 mm long, and at another moment for stacks of regular flat-folded cartons, where a stack may be e.g. 500 mm long.FIG.2shows an example of a feeding device adapted for long stacks of folded cartons. In this example, only a few teeth are positioned in an erected position by the switch.

It is also possible to use only two rows of foldable teeth for smaller flat-folded cartons that are not as wide as the conveyor track. It is e.g. possible to erect teeth in two adjacent rows of teeth, and to let the third row of teeth be constantly in a folded state. This will allow the feeding device to be used for smaller cartons, or cartons having an odd shape, e.g. with an extended side flap. In the shown example, separate switches are used for each row of teeth. The switch may also fold a parallel set of teeth at the same time, using a single switch member acting on all rows at the same time.

By erecting all teeth, it is ensured that all teeth have the same orientation, and the switch can be made simple since it does not have to both erect and/or fold each tooth. In the shown example, the switch will only fold the teeth that needs to be folded. In another example, the switches could be positioned inside the conveyor chains. In such a case, an erecting member would not be used and all teeth would arrive to the switches in a folded state. The switch would in this case only erect the teeth that should be erected.

In the inventive method for feeding stacks of standing flat-folded cartons by a feeding device from an infeed region of the feeding device to a receiving station where the stacks are merged, the feeding device is adapted to convey and merge stacks having different lengths. The stacks are conveyed by a conveyor track comprising a plurality of teeth.

In step100, the length of the stacks of flat-folded cartons that are to be conveyed by the feeding device is determined and is saved in a control unit for the feeding device.

In step110, a selected number of teeth of the conveyor track are consecutively set to an erected position with a positioning device in the return path of the conveyor track. The selected number of teeth are set in dependency of the determined length of a carton stack. The length of a stack sets the distance between two erected teeth, which determines the required position for each tooth. With a short stack, all teeth may have to be erected. With a longer stack, some of the teeth must be folded, such that the distance between two erected teeth corresponds to the length of the stack.

In step120, a stack of flat-folded cartons is inserted between the teeth at the infeed region. A stack may be inserted by hand or by a stack placing machine.

In step130, the teeth are held in the selected position by a guide track arranged along the bearing plane of the conveyor track.

In step140, the teeth are released from the selected position at an end region of the feeding device, such that the teeth are unsupported by a guide track, and such that the teeth are supported by the stacks of flat-folded cartons. In this way, the teeth will not push on, disturb or damage the stacks of flat-folded cartons at the outfeed region. The stack of flat-folded cartons merges with the previous stacks. Here, the teeth stop pushing the stack of flat-folded cartons, and the stack is merged with the next stack and the complete merged stack of flat-folded cartons is pushed by the teeth of that stack.

In step150, the teeth are withdrawn in a vertical orientation. The teeth of the conveyor track leaves the guide track and the teeth retracts downwards to the return path.

In step160, the stack will merge with previous stacks at the outfeed region of the feeding device.

In an additional step, the speed of the conveyor track is adjusted to a pick-up speed at the receiving station. The pick-up speed may e.g. be the speed at which a carton erecting machine picks up folded cartons from the merged pack of folded cartons. In this way, the density of flat-folded cartons at the outfeed track will be more or less constant, which will provide a sufficient forward pressure on the foremost carton, such that a reliable pick-up of the carton is ensured. At the same time, it is ensured that the flat-folded cartons will keep their standing orientation such that they don't fall over or tilt too much.

The invention is not to be regarded as being limited to the embodiments described above, a number of additional variants and modifications being possible within the scope of the subsequent patent claims.

REFERENCE SIGNS

1: Feeding device2: Stack of flat-folded cartons3: Bearing plane4: Housing5: First row of teeth6: Second row of teeth7: Third row of teeth8: First chain9: Second chain10: Third chain11: Drive unit12: Display tab13: Outfeed region14: Sliding track15: End region16: Pushing member17: Tooth18: Bearing surface19: Pushing surface20: Frame21: Cover surface22: Pivot point23: Roller24: Guide track25: Switch26: Switch cylinder27: Switch member28: Actuating tab29: Pivot point30: Conveyor track31: Outfeed conveyor32: Infeed region33: Erecting member34: Drive wheel35: Slide rail