Method and device for forming product stacks of folded or unfolded product blanks made of paper, chemical pulp or the like

Abstract

In a method for forming product stacks of folded or unfolded product blanks made of paper or chemical pulp, product blanks are supplied consecutively to a stacking surface and placed in an upright position. A separating element is inserted between two consecutive product blanks as the product blanks are moved against a channel wall of a discharge channel for temporary support of a rear side of the product blanks, to thereby form a first product stack with a predetermined number of product blanks between the separating element and the channel wall. The channel wall is opened to thereby allow the first product stack to be transferred to the discharge channel, and a sliding element is inserted between the product stack and a subsequent second product stack, as the first product stack is moved to the discharge channel.

Claims

1. A method for forming product stacks of folded or unfolded product blanks made of paper or chemical pulp, said method comprising: supplying product blanks consecutively to a stacking surface and placing them in an upright position; inserting a separating element between two consecutive product blanks as the product blanks are moved against a channel wall of a discharge channel for temporary support of a rear side of the product blanks, to thereby form a first product stack with a predetermined number of product blanks between the separating element and the channel wall; opening the channel wall, thereby allowing the first product stack to be transferred to the discharge channel; and inserting a sliding element between the product stack and a subsequent second product stack, as the first product stack is moved to the discharge channel.

2. The method of claim 1, wherein the separating element is moved towards the channel wall after being inserted between the product blanks.

3. The method of claim 1, further comprising temporarily supporting a rear side of the second product stack by the separating element, as the first product stack is moved to the discharge channel.

4. The method of claim 1, further comprising grouping the product blanks together in two or more processing lines into plural product stacks which are jointly moved to the discharge channel.

5. A device for forming product stacks of folded or unfolded product blanks made of paper or chemical pulp, said device comprising: a discharge channel having a movable channel wall; a stacking surface arranged upstream of the discharge channel to allow a product stack to be transferred to the discharge wall, when the channel wall is temporarily moved to an open position; and a separating element configured for insertion between two product blanks, said separating element being movable in an insertion direction which is transverse to a conveying direction of the product blanks to the discharge channel.

6. The device of claim 5, wherein the separating element is configured for movement in a substantially horizontal conveying direction of the product stack.

7. The device of claim 5, further comprising a sliding element configured for movement in a substantially horizontal conveying direction of the product stack.

8. The device of claim 7, wherein the sliding element is configured for movement in the conveying direction of the product stack at a speed which is greater than a speed by which the separating element is moved.

9. The device of claim 7, wherein at least one of the sliding element and the separating element is configured in the form of a sliding rake or separating rake.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1 shows a device for forming product stacks of product blanks,

(2) FIG. 2 shows a serrated disc of the device according to FIG. 1, and

(3) FIGS. 3 a to f show the device according to FIG. 1 in a plurality of moments during the process operation.

(4) The same parts are provided with the same reference numerals in all the drawings.

(5) The device 1 according to FIG. 1 is provided to form product stacks 2 from a plurality of product blanks 4 which are firstly supplied individually. In the embodiment, the product blanks 4 are paper pocket tissues, that is to say product blanks 4 made of chemical pulp which are to be portioned ready for sale in a subsequent packaging system, for example are to be packaged in packaging units of packs of 5 or 10.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(6) Accordingly, the individually supplied product blanks 4, that is to say the individual pocket tissues, are grouped together in the device 1 into product stacks 2 which each comprise five or ten individual pocket tissues. Alternatively, the device 1 could of course also be provided for forming stacks of other products such as hygiene products, pantyliners, sanitary pads or the like or also for products made of paper such as envelopes or the like.

(7) The device 1 is provided for separating and forming stacks of the product blanks 4 in a substantially vertical orientation, that is to say upright. For this purpose, the device 1 comprises a supply unit for the individual pocket tissues or the individual product blanks 4. The supply unit is designed in the embodiment as what is known as a serrated disc 6, as is used in a perfectly conventional manner for such purposes. The serrated disc 6 comprises in this case cavities 8 which are distributed in a suitably positioned and contoured manner over the circumference thereof and are formed by suitably contoured teeth 10. The contour of the teeth 10 and of the cavities 8 formed thereby is selected such that the folded paper pocket tissues or product blanks 4 to be transported can be reliably held, guided and further transported along the circumference of the serrated disc 6.

(8) As a result of the rotation of the serrated disc 6, said disc guides the product blanks 4 from the bottom up to an output position. This embodiment allows for a particularly advantageous process operation, since when the product blanks 4 are placed down, a comparatively low end speed of the product blanks 4 in the vertical direction can be achieved, as a result of gravity, directly before the actual placing down. In order to make this operation possible, that is to say in particular the guiding from the bottom up to the output position, without there being a risk of the product blanks 4 falling out of the cavities 8, the serrated disc 6 is designed in a specific manner which is considered to be independently inventive, as can be seen in the enlarged view in FIG. 2. Since in particular in the mentioned guiding from the bottom up of the product blanks 4 to the output position thereof, both centrifugal force, occurring as a result of rotation, and gravity are to be expected, which could both cause the respective product blanks 4 to fall out of the corresponding cavity 8, the serrated disc 6 is designed to at least temporarily apply a retaining force which fixes the product blanks 4 in the respective cavity 8.

(9) In the embodiment, the application of this retaining force is provided by means of a suction vacuum. For this purpose, in the main body 11 of the serrated disc 6, a vacuum channel 12 is integrated for each cavity 8, which channel connects a suction hole 13 which is arranged on the inner side of the serrated disc 6 to an intake hole 14 which opens out into each cavity 8. By means of an assigned negative pressure system, the intake holes 14 have a vacuum applied thereto in a timed manner such that in the phase of conveying a product blank 4 in the serrated disc 6, said blank is fixed in the respective cavity 8 by means of the vacuum. Shortly before reaching the output position, the suction vacuum in each cavity 8 is switched off and each product blank 4 is thus released so that said blank can subsequently be output and placed down.

(10) In FIG. 1, for the sake of clarity, only one of the product blanks 4 is shown in the region of the output position in the respective cavity 8. In the output position, the serrated disc 6 places each supplied product blank 4 in an upright or on-edge orientation on a stacking surface 15 in the stated manner, which surface is formed in the embodiment by a plurality of conveyor belts which are guided in parallel with one another and are not visible in the drawing. By means of said belts, the supplied product blanks 4 which are placed upright are transported in a transport direction or conveying direction indicated by the arrow 16 to an assigned discharge channel 17. The discharge channel 17 is designed to transport the products further in a discharge direction which is transverse to the conveying direction or at an angle of 90 to the conveying direction and is represented by the arrow 18.

(11) This removal of the product blanks 4 is intended to take place in stacks, that is to say in the form of the product stacks 2, in the discharge channel 17. In order to make this possible, the device 1 is designed for a suitable stack formation from the product blanks 4. In order to carry out the stack formation and the subsequent feed into the discharge channel 17, the discharge channel 17 is designed having a movable side wall or channel wall 20. During the removal of the products, the channel wall 20 is essentially closed so that reliable lateral support of the product stacks 2 transported in the discharge channel 17 is ensured. However, in the embodiment according to FIG. 1, for the sake of better comprehension, the discharge channel 17 is shown in a phase in which the channel wall 20 is temporarily open, so that it is possible to insert the finished product stack 2 into the discharge channel 17.

(12) During the stack formation, the channel wall 20 is firstly closed and in the process is used to support the rear side of the product stack 2 which is being formed from the supplied product blanks 4. In order to form the product stack 2, a separating element 22 which is designed in the form of a rake is provided, which, based on the conveying direction of the product blanks 4 which is represented by the arrow 14, can be inserted between two consecutive product blanks 4 transversely to said conveying direction in an insertion direction represented by the arrow 24. In the embodiment according to FIG. 1, an insertion of the separating element 22 from the bottom up, that is to say in the vertical direction, into the product flow is provided; alternatively however, an insertion from the side could of course also be provided. In the case of the separating element 22 which is inserted into the product flow, said element separates the already formed product stack 2 from the consecutive additional supplied product blanks 4. After the insertion of the separating element 22 into the product flow, as shown in FIG. 1, the channel wall 20 is opened so that the product stack 2 originally located between the channel 20 and the separating element 22 can be inserted into the discharge channel 17.

(13) In this phase, that is to say when the channel wall 20 is open and the product stack 2 can be inserted into the discharge channel 17, the separating element 22 acts as a support for the consecutively arriving product blanks 4 in the manner of a movable rear wall. The separating element 22 is accordingly additionally mounted so as to be movable in the conveying direction of the product blanks 4 which is represented by the arrow 14. In order to provide sufficient space for the consecutively arriving additional product blanks 4 to be placed on the stacking surface 12, after the channel wall 20 has been opened, the separating element 22 moves towards the discharge channel 17 at a comparatively slow speed in the conveying direction represented by the arrow 14; the speed of said movement of the separating element 22 is such that the separating element 22 forms a movable rear wall for the continuous support of the new product stack 2 being formed, which stack is increasingly large as a result of the new product blanks 4 being added.

(14) For the actual introduction of the product stack 2 into the discharge channel 17, the device 1 comprises another sliding element 30 which is likewise in the form of a rake. In this case, in the embodiment the sliding element 30 can be inserted, in the same manner as the separating element 22, in an insertion direction which is represented by the arrow 32, vertically from the top down, and thus also transversely to the conveying direction of the product blanks 4 which is represented by the arrow 14, likewise between the product blanks 4 delimiting the product stack 2 on one side and the product stack following said product stack on the other side. In the embodiment, the fact that both the separating element 22 and the sliding element 30 are in the form of rakes makes it possible for the respective teeth of said rakes, which are positioned so as to be laterally offset in a suitable manner with respect to one another, can interlock in a suitable manner, so that it is possible to insert both the separating element 22 and the sliding element 30 at the same point of separation between two adjacent product blanks 4 without obstruction.

(15) After the insertion, the sliding element 30 is subsequently moved towards the discharge channel 17 in the conveying direction of the product blanks 4 at a speed which is selected to be suitably higher by comparison with the speed of the separating element 22 and thereby inserts the already formed product stack 2 into the discharge channel 17.

(16) The movement sequence of the components is shown schematically in a lateral view in the sequence of FIG. 3a to 3f. In FIG. 3a, firstly the state is shown in which the serrated disc 6 has already placed a plurality of product blanks 4 upright on the stacking surface 12. In FIG. 3a, the channel wall 20 of the discharge channel 17 is still closed, so that in this phase, the rear side of the product blanks 4 which have already been placed down in an upright manner can be supported temporarily by the channel wall 20. FIG. 3a also shows the separating element 22 in the form of a rake, which, at the moment shown in FIG. 3a, is moved towards the stacking surface 12 substantially in parallel with the movement profile with which the serrated disc 6 supplies the product blanks 4 to said surface. Accordingly, the separating element 22 in the situation shown in FIG. 3a is moved in the insertion direction represented by the arrow 24 from the bottom up and is thereby inserted between two consecutive product blanks 4. The movement of the separating element 22 takes place, in terms of directional guiding and movement speed, in sync with the movements of the product blanks 4 such that said movement can be kept substantially free of contact and thus free of obstruction.

(17) Shortly after, as shown in FIG. 3b, the separating element 22 is moved completely upwards into the end position thereof and thus separates the already formed product stack 2 from the additional product blanks 4 which are subsequently supplied by the serrated disc 6. In this phase, the channel wall 20 of the discharge channel 17 is still closed and additionally supports the rear side of the product blanks 4 which have been placed down. Directly thereafter, as can be seen in the moment in FIG. 3c, the separating element 22 is moved towards the discharge channel 17 and thus towards the channel wall 20 at a comparatively slow speed in the conveying direction of the product blanks 4 which is represented by the arrow 14. The separating element 22 thus becomes a movable rear wall for the new product blanks 4 which are arriving, which wall increasingly moves out of the way towards the channel wall 20 and thus provides more and more space on the stacking surface 12 for new product blanks 4 which are arriving.

(18) As can additionally be seen from the moment in FIG. 3c, the sliding element 30 is also supplied in sync with the movement sequences. In the moment according to FIG. 3d, the moment is shown at which the sliding element 30 is located in the same position as the separating element 22 and is also inserted between the product blanks 4. At this moment, in sync with the mentioned movements and adapted thereto, the channel wall 20 is opened so that the discharge channel 17 is freely accessible. In the subsequent step, as shown in the moment according to FIG. 3e, the sliding element 30 is moved towards the discharge channel 17 at a considerably increased speed by comparison with the separating element 22 in the conveying direction of the product blanks 4 which is indicated by the arrow 14, said channel now being completely released as a result of the channel wall 20 being completely open. The product stack 2 is thus inserted into the discharge channel 17 by means of the sliding element 30. In this phase, the separating element 22 which is moving comparatively slowly towards the discharge channel 17 takes over the function of the movable rear wall for the consecutive product blanks 4 and supports the rear side of the product blanks 4 which have already arrived and are forming the new product stack.

(19) In a subsequent step, after the product stack 2 has been completely inserted into the discharge channel 17, and as is shown in the moment according to FIG. 3f, the channel wall 20 is closed again so that it is possible to remove the product stack 2 which has been introduced into the discharge channel 17. The sliding element 30 is now moved temporarily into an inoperative position. At this moment, as indicated by the arrow 24, the separating element 22 is removed downwards and out of the region of the product flow in the opposite direction to the insertion direction. The supporting function for the product stack being formed from the product blanks 4 can now be taken over again by the already closed channel wall 20. After the separating element 22 has been moved completely downwards and out of the region of the product flow, said element can be moved, under the product flow in the opposite direction to the conveying direction of the product flow which is indicated by the arrow 14, that is to say to the left in the embodiment according to FIG. 3f, back to the original position thereof. The state shown in FIG. 3a is thus assumed again, and the movement cycle can start anew.

(20) As viewed from a lateral direction, the separating element 22 thus carries out a movement having a rectangular movement profile over the entire cycle, that is to say firstly the insertion movement into the product flow in a substantially vertical direction from the bottom up, then, in a position in which said element is inserted between two product blanks 4, the movement out of the way towards the channel wall 20 in a substantially horizontal conveying direction of the product blanks 4, subsequently the removal from the product flow in a substantially vertical direction from the top down, and lastly the backwards movement below the product flow in the opposite direction to the conveying direction of the product blanks 4 as far as to the insertion point.