Carton stack divider and method for dividing a stack

Abstract

A divider for dividing a pack of flat-folded cartons into a plurality of stacks of flat-folded cartons, the divider comprising a magazine adapted to hold the carton pack, where the magazine includes a stop member, and where the divider includes a pusher member and a holder foot, where the magazine is arranged in an inclined position, where the pusher member is adapted to compress the carton pack between the pusher member and the stop member, where the holder foot is adapted to bear on the upper side of the compressed carton pack, and where the pusher member is adapted to release the pressure on the carton pack when the holder foot bears on the upper side of the carton pack, thereby creating a low density area adjacent a first carton stack.

Claims

1. A divider for dividing a carton pack of flat-folded cartons into a plurality of stacks of flat-folded cartons, the divider comprising a magazine adapted to hold the carton pack, wherein the magazine includes a stop member, wherein the magazine is arranged in an inclined position, and wherein the divider includes a pusher member and a holder foot, wherein the pusher member is adapted to compress the carton pack between the pusher member and the stop member, that the holder foot is adapted to be lowered to and to bear on a first side of the compressed carton pack, when the carton pack is compressed by the pusher member, thereby holding a first stack of flat-folded cartons and that the pusher member is adapted to release the pressure on the carton pack when the holder foot bears on the first side of the carton pack, thereby creating a low density area adjacent the first carton stack, wherein the divider further includes a parting device having a parting tip adapted to be inserted in the low density area after the holder foot bears on the upper side of the first stack of flat folded cartons and the pressure has been released by the pusher member, and wherein the pusher member is adapted to measure a value from which the length of the carton pack can be estimated.

2. The divider according to claim 1, wherein the pusher member, after the carton pack has been compressed and before the holder foot bears on the carton pack, is adapted to be retracted a predefined amount in dependency of the estimated length of the carton pack.

3. The divider according to claim 1, wherein the parting tip includes a parting finger adapted to extend from the parting tip such that a well-defined gap is created between the first stack and the remaining carton pack.

4. The divider according to claim 1, wherein the parting tip is arranged at a front end of a parting arm, where the parting arm is pivotally suspended at a rear end of the parting arm.

5. The divider according to claim 1, wherein the inclined position of the magazine is between 45 to 60 degrees from the horizontal position.

6. The divider according to claim 1, wherein the holder foot is mounted on a first linear actuator adapted to move the holder foot from a first position spaced apart from the carton pack to a position in which the holder foot bears on the first side of the carton pack.

7. The divider according to claim 1, wherein the parting device is mounted on a second linear actuator adapted to move the parting device from an upper position above the carton pack to a lower position in which the parting tip is inserted into the low density area.

8. The divider according to claim 1, wherein the divider includes a support finger adapted to be inserted between a first stack and the remaining carton pack.

9. A method for dividing a pack of flat-folded cartons using a divider, comprising: arranging a magazine comprising a carton pack in an inclined position, compressing the carton pack with a pusher member, moving a holder foot from a position spaced apart from the carton pack to a position in which the holder foot bears on a first side of the carton pack when the carton pack is compressed by the pusher member, releasing the pressure of the pusher member by retracting the pusher member, where the flat-folded cartons held by the holder foot constitute a first stack of flat-folded cartons, and where the remaining carton pack held by the pusher member is allowed to move downwards, thereby creating a low density area adjacent the first stack; inserting a parting tip between two flat-folded cartons in the low density area after the holder foot bears on the upper side of the first stack of flat-folded cartons and after the pressure has been released by the pusher member, and detecting with a sensor if the support finger did enter between two flat-folded cartons in the low density area.

10. A method according to claim 9, further comprising creating a well-defined gap between the first stack and the remaining carton pack by extending a parting finger from the parting tip.

11. A method according to claim 10, further comprising lowering a support finger into the well-defined gap between the first stack and the remaining carton pack.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The invention will be described in greater detail in the following, with reference to the embodiments that are shown in the attached drawings, in which

(2) FIG. 1 shows a divider according to the invention with a magazine in a horizontal position,

(3) FIG. 2 shows a divider according to the invention with an extended pusher member,

(4) FIG. 3 shows a divider according to the invention with an inclined magazine,

(5) FIG. 4 shows a divider according to the invention with a lowered holder foot,

(6) FIG. 5a shows a divider according to the invention when a carton pack is being divided,

(7) FIG. 5b shows a detail of FIG. 5a,

(8) FIG. 6a shows a divided pack where a parting tip has entered the low density area,

(9) FIG. 6b shows a detail of FIG. 6a,

(10) FIG. 7 shows a divider according to the invention with a well-defined gap,

(11) FIG. 8 shows the divider according to the invention with a lowered support finger, and

(12) FIG. 9 shows a flowchart of a method for dividing a pack of flat cartons according to the invention.

MODES FOR CARRYING OUT THE INVENTION

(13) 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 divider in use and to the pack of cartons.

(14) The divider 10 according to the invention comprises a tiltable table 20 adapted to support a magazine 23, a pusher member 19 and a holder foot 18. The divider is adapted for dividing a carton pack 12 of flat-folded cartons 11 which in the described example is fed to the divider in a horizontal orientation. It is however possible to feed the pack of flat-folded cartons to the magazine in another orientation. In the described example, the divider also comprises a parting tip 34 and a support finger 41. FIG. 1 shows a perspective view of a divider 10 with a magazine in a horizontal position before the dividing of the carton pack has started. Here, the tiltable table 20 is in a horizontal position and the pusher member 19 is in a retracted position. A pack of cartons 12 is positioned in the magazine. The carton pack may be fed to the divider by replacing an empty magazine with a full magazine, or the carton pack may be placed in the magazine by a feeder device. A pack of cartons may correspond to e.g. two to four carton stacks. The carton pack 12 is arranged on a carton plane 13 in the magazine and is supported by stop members 14 at the front of the magazine. The pusher member 19 comprises in this example two pusher arms and is adapted to compress the carton pack 12. The magazine may also be permanently arranged in an inclined position.

(15) In the shown example, the holder foot 18 is mounted on a first linear actuator 42 adapted to move the holder foot from a position spaced-apart from the carton pack to a position in which the holder foot bears on a first side 21 of the carton pack 12. The first side may be the upper side or the lower side of the carton pack. In the shown example, the holder foot is arranged in a position above the carton pack, but it is possible to arrange the holder foot in a position below the carton pack. A parting device 32 comprising a parting arm 33 with a parting tip 34 is mounted on a second linear actuator 43 adapted to move the parting device from an upper position above the carton pack to a lower position in which the parting device bears on the upper side of the carton pack. The support finger 41 is mounted on a third linear actuator 44, which is adapted to move the support finger from an upper position above the carton pack to a lower position in which the support finger is positioned between the first stack and the remaining carton pack. The linear actuators may e.g. be air actuators or electrical actuators. A typical example of a carton pack may comprise 520 flat-folded cartons and is to be divided into three carton stacks, comprising approximately the same number of flat-folded cartons. In this example, the three carton stacks that are to be divided from the carton pack are the first carton stack 15, the second carton stack 16 and the third carton stack 17.

(16) In FIG. 2, the pusher member 19 has compressed the carton pack 12 by extending the pusher member 19 from the idle position to a position in which the carton pack is compressed to a predefined extent. The idle position for the pusher member is in its most retracted position at the rear end of the magazine 23. The pusher member 19 will extend forwards by e.g. a drive motor or a linear actuator and will compress the carton pack until a predefined compression is reached. In the shown example, the pusher member 19 is mounted to a fourth linear actuator 45 and is here an electrical actuator that uses an electrical rotary motor for the movement of the pusher member. The compression value can be detected e.g. by a pressure sensor or by detecting the drive current to the drive motor. During the compression, the travelled distance of the pusher member is measured at the same time, e.g. by the use of a decoder measuring the rotation of the drive motor or by a linear encoder. In this way, a measure which can be used to estimate the length of the compressed carton pack is obtained. From this value, the number of flat-folded cartons in the carton pack can be determined.

(17) The carton pack preferably contains a predefined number of flat-folded cartons, in the shown example 520 cartons, and three stacks will be created from the carton pack. It is preferred that the created stacks are more or less equal in size. In this example, each stack will thus contain approximately 173 flat-folded cartons, which can be seen as a nominal value for a carton stack. The carton stacks do not have to be exactly the same size, but should be approximately a third of the carton pack. Depending on the tolerances of the gripper device that will collect the stack, a stack may comprise e.g. between 160-180 flat-folded cartons.

(18) The size of a pack of flat-folded cartons may vary, depending on how a carton pack is assembled at the production site producing the carton packs. The number of flat-folded cartons in a carton pack may vary between e.g. 500-550 flat-folded cartons. The allowed range for a carton pack may be e.g. 500-540 flat-folded cartons. By determining the number of flat-folded cartons in a carton pack, it is also possible to determine if the number of flat-folded cartons in the carton pack is within the allowed range. If it is determined that the number of flat-folded cartons in the carton pack is above or below the allowed range, the complete carton pack can be discarded and a new carton pack can be collected to the magazine.

(19) If the number of flat-folded cartons is within the allowed range, the size of the carton pack is used to determine the size of the stacks that are to be created.

(20) The size of the carton pack is divided by three. The holder foot is in the shown example positioned at a fixed position that corresponds to a nominal carton stack size. The position of the holder foot may be adapted to either a nominal carton pack or to the largest allowed carton pack. This fixed position will give three equal stacks from the carton pack. If the size of the carton pack differs from this size, the pusher member is arranged to retract somewhat in order to make sure that the first stack will contain approximately a third of the flat-folded cartons. It is also possible to let the pusher member retract somewhat every time, either by a predefined value or in dependency of the estimated number of cartons in the carton pack.

(21) In FIG. 3, the tiltable table 20 with the magazine 23 has been raised to an inclined position. It is also possible to permanently arrange the table in an inclined position. The inclined position is preferably in the range between 30 to 70 degrees relative the horizontal plane, and more preferably in the range between 45 to 60 degrees. With such an inclination, the flat-folded cartons will remain in the magazine without falling out and will also be able to easily slide down in the magazine by gravity when the pusher member is retracted. It would be possible to incline the table by 90 degrees, but this will require support means to hold the flat-folded cartons in the magazine.

(22) In FIG. 4, the holder foot 18 has been lowered and bears on the upper side 21 of a plurality of flat-folded cartons 11 in the carton pack 12, e.g. on 3-10 flat-folded cartons. The holder foot is provided with a friction material, e.g. rubber or plastic that will secure a firm hold of the flat-folded cartons and at the same time make sure that the cartons are not damaged. The holder foot will hold the rearmost flat-folded cartons of the first stack 15.

(23) In FIG. 5a, the pusher member 19 has been retracted somewhat. The pusher member may retract to the idle position or to an intermediate position in which a sufficiently large low density area 22 or even a void is created adjacent the first stack. When the pusher member is retracted, the compression of the remaining carton pack will be lowered and the carton pack will follow the pusher member downwards. When the pressure on the flat-folded cartons in the remaining carton pack is released, the flat-folded cartons may expand some. This will lower the density of flat-folded cartons in the remaining carton pack and especially at the upper region of the remaining carton pack, and may even create a void between the first carton stack and the remaining carton pack. The flat-folded cartons in the first carton stack held by the holder foot will remain compressed. A first stack of flat-folded cartons has now been created. The first stack can be gripped by a gripping device. FIG. 5b shows a detail of FIG. 5a, where the difference in density between the compressed first carton stack 15 held by the holder foot 18 and the remaining carton pack is visible. The carton density in the remaining carton pack will vary some over the length of the remaining carton pack, with the lowest carton density at the upper part, close to the first carton stack. The area closest to the first carton stack is referred to as the low density area 22.

(24) In the shown example, a parting tip is inserted into the low density area in order to make sure that there is no misaligned carton in the low density area and to obtain a well-defined gap between the first stack and the remaining carton pack. The reduced density in the low density area will allow the parting tip 34 to fall down between two flat-folded cartons 11. In FIG. 6a, the parting device 32 has been lowered and bears on the remaining carton pack. The parting device comprises a parting arm 33 having a parting tip 34 with a parting edge 35. The parting tip 34 has entered the low density area successfully. FIG. 6b shows a detail of FIG. 6a, where the parting tip 34 can be seen between two flat-folded cartons 11 in the low density area 22. When the parting tip has entered the low density area, the holder foot will be raised from the lower position to its idle position.

(25) The parting tip 34 is arranged on the parting arm 33 which is suspended at a rear end of the parting device 32 at a pivot axle. The pivot axle is mounted to a bracket 39 which is mounted to the second linear actuator 43. The bracket is provided with a sensor which is adapted to detect the position of the parting arm and thus the parting tip. The parting arm is provided with a detection plate. The position of the detection plate can be detected by the sensor. The sensor may e.g. be a magnetic sensor or an optical fork coupler or reflex coupler. The sensor detects when the arm and thus the tip is in a raised position or when the parting tip has entered the low density area. The parting edge 35 of the parting tip 34 is pointed with a relatively small radius, but is not sharp. The shown parting tip further comprises two parting fingers 36 arranged on both sides of the parting edge 35. The parting fingers can be extended rearwards or forwards from the parting tip by the use of an actuator integrated in the parting arm. The parting tip and the parting fingers are relatively thin, and are preferably one or a few millimetres thick.

(26) When the parting device 20 is lowered by the second linear actuator 43, the parting tip will be able to enter between two flat-folded cartons of the low density area. If there is a warped flat-folded carton or a flat-folded carton arranged in diagonal in the low density area, the parting tip may rest on the flat-folded carton and will not be able to fall down between two flat-folded cartons. This will be detected by the sensor, and may abort the dividing of the carton pack. In one example, the dividing of the carton pack is repeated by raising the parting device and the holder foot and by compressing the carton pack again. Thereafter, the holder foot is lowered onto the upper side of the carton pack, and the pusher member is retracted once more, such that a new try is made to divide the pack. If this try does not succeed, an error message may be given. It is also possible to abort the dividing of the carton pack immediately and to give an error message right away. By detecting if the carton pack was divided successfully, it can be ensured that the gripping device will be able to grip a proper stack of cartons. If a gripping device would grip a stack that is not divided in a successful way, one or more cartons may be damaged and the production line may have to stop.

(27) In order to provide a more well-defined gap and to simplify the pick-up of the stack by a gripping device, the distance between two cartons in the low density area can be enlarged. In the shown example, the parting tip 34 is provided with two parting fingers 36. The parting fingers are arranged on each side of the parting tip 34 and are adapted to extend forwards from the parting tip, thereby compressing the first stack some in order to create a well-defined gap. The parting fingers are in this example moved by a linear actuator integrated in the parting arm. By extending the parting fingers forwards, a well-defined gap 47 is created. A parting device 32 with parting fingers 36 extended from the parting tip 34 is shown in FIG. 7.

(28) The shown divider is also provided with a support finger 41. The support finger is mounted on a third linear actuator 44. The support finger is lowered into the gap 47 by lowering the third linear actuator, as can be seen in FIG. 8. When the support finger has been lowered, the parting device 32 is raised to its idle position and the support finger 41 supports the rear of the first carton stack 15 and the front of the remaining carton pack. It is also possible to lower the support finger into the low density area without using the parting device with the parting fingers. This use of parting fingers and/or a support finger may e.g. depend on the design of the gripping device. Lowering the support finger in the gap created by the parting tip and the parting fingers will also prevent damage of the surfaces of the cartons and will ensure that there is no flat-folded carton in the gap.

(29) When the first carton stack 15 has been picked up by a gripping device, the divider will be prepared for dividing a new carton stack. The pusher member will compress the remaining carton pack, the holder foot will be lowered to bear on the upper side of the remaining carton pack, and the pusher member will retract some in order to create a new low density area or even a void adjacent the second stack 16. The parting device and the support finger will be used in the same way as described above. When the second stack 16 of flat-folded cartons has been picked up by the gripping device, the pusher member pushes the third stack 17 forwards to the front of the magazine where it is picked up by the gripping device. The pusher member is then retracted to the idle position and a new pack of flat-folded cartons is placed in the magazine.

(30) In the inventive method for dividing a pack of flat-folded cartons, the pack is divided by using a divider. In step 100, the carton pack is compressed by the pusher member.

(31) In step 110, the carton pack is arranged in an inclined position, e.g. by tilting the magazine holding the carton pack.

(32) In step 120, the holder foot is moved towards the carton pack such that it bears on the carton pack.

(33) In step 130, the pusher member is retracted. This will create a low density area adjacent the flat-folded cartons held by the holder foot. The remaining carton pack will follow the pusher member downwards by gravity which creates the low density area or a void.

(34) In step 140, the parting tip is inserted into the low density area. Parting fingers are extended from the parting tip in order to create a well-defined gap.

(35) In step 150, a support finger is inserted in the well-defined gap created by the parting fingers.

(36) The divider and the method for dividing a pack of flat-folded cartons can be used in any packing plant or other facility where such a divider or method can be used for dividing packs of flat-folded cartons or other flat-folded items. The divider, arrangement or method may also be used with larger flat-folded cartons such as e.g. folded cardboard boxes, or plastic boxes.

(37) 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

(38) 10: Divider

(39) 11: Flat-folded carton

(40) 12: Pack of flat-folded cartons

(41) 13: Carton plane

(42) 14: Stop member

(43) 15: First stack of flat-folded cartons

(44) 16: Second stack of flat-folded cartons

(45) 17: Third stack of flat-folded cartons

(46) 18: Holder foot

(47) 19: Pusher member

(48) 20: Tiltable table

(49) 21: Upper side of carton pack

(50) 22: Low density area

(51) 23: Magazine

(52) 32: Parting device

(53) 33: Parting arm

(54) 34: Parting tip

(55) 35: Parting edge

(56) 36: Parting finger

(57) 39: Bracket

(58) 41: Support finger

(59) 42: First linear actuator

(60) 43: Second linear actuator

(61) 44: Third linear actuator

(62) 45: Fourth linear actuator

(63) 47: Gap