Winding apparatus for winding a web into a roll

Abstract

A winding apparatus for winding a web material onto an empty core and into a roll, having a winding drum for guiding the web material supported on a first side, and cutting device for cross-cutting the web material prior to winding of it onto an empty core. The winding apparatus has air nozzles for ejecting compressed air onto the first side of the web material near a free end of the web material. By ejecting a gas, which preferably could be compressed air, onto the free end of the web, the free end is blown towards the empty core which is rotated. When the free end of the web material comes into contact with the rotating empty core, due to the ejected gas/air, the web will easily be caught by the rotating empty core, even without tape or adhesive, and a smooth new roll of web material wound.

Claims

1. A winding apparatus configured for winding a web material, comprising a first and a second side and a free end onto an empty core and into a roll, said winding apparatus comprising a winding drum for guiding said web material by supporting said web material on the first side, and further comprising cutting means for cross cutting said web material prior to said web material being wound onto an empty core, said winding apparatus further comprises means for moving said empty core from a first position to a second position, said means comprising a set of retainer arms for carrying and moving said core from said first position to said second position near the periphery of said winding drum while web material is being wound onto said core, and for carrying at least one roller, said roller being arranged to lift said web material from said winding drum, during winding, prior to cross cutting said web material along said roller and thus creating said free end of web material, wherein said winding apparatus further comprises nozzle means for ejecting a gas onto the first side of said web material near said free end of said web material, wherein said nozzle means comprise a cross bar extending substantially in parallel with said winding drum, said cross bar comprising a number of nozzles which are distributed across the entire length of the cross bar, said nozzles being directed towards the first side of said web material, and wherein said cross bar is hollow and comprises at least two internal compartments for said gas, said compartments extending along the length of said cross bar and communicating with respective ones of said nozzles.

2. The winding apparatus according to claim 1, wherein said winding apparatus comprises further nozzle means, said further nozzle means also being directed towards the first side of said web material and arranged along the winding drum.

3. The winding apparatus according to claim 1, wherein said cutting means comprise a knife unit, said knife unit further comprising nozzle means for ejecting gas towards the first side of the web material while cutting said web material.

4. The winding apparatus according to claim 1, wherein said cutting means comprise a mechanism that allows said knife unit to be moved along the winding drum while in contact with said web material, said mechanism comprising means for moving said cutting means across said web material.

5. The winding apparatus according to claim 1, wherein said cutting means comprise a knife unit, and further comprise a stationary cross bar, said cross bar having a recess in the longitudinal direction, where at least a part of said knife unit is moved in said recess.

6. The winding apparatus according to claim 1, wherein said cutting means comprise a knife unit, said knife unit being installed in and driven along a stationary cross bar.

7. The winding apparatus according to claim 1, wherein air at a first lower pressure is expelled from the cross bar prior to cutting of the web.

8. The winding apparatus according to claim 7, wherein an air blast at a second higher pressure is expelled from the cross bar during or immediately after cutting of the web.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a winding apparatus during winding of a web and with the retainer arms in a 6 o'clock position.

(2) FIG. 2 shows a winding apparatus during winding of a web and with the retainer arms in a 9 o'clock position and preparing for a change of core/roll.

(3) FIG. 3 shows a winding apparatus during winding of a web and with the retainer arms in a 12 o'clock position and preparing for a change of core/roll.

(4) FIG. 4 shows a winding apparatus during winding of a web and with the retainer arms in a 12 o'clock position with an empty core in position.

(5) FIG. 5 shows a winding apparatus during winding of a web and with the retainer arms in a 12 o'clock position with the knife unit in position and ready to cut.

(6) FIG. 6 shows a winding apparatus during winding of a web and with the retainer arms in a 12 o'clock position just after cutting the web.

(7) FIG. 7 shows a winding apparatus during winding of a web and with the retainer arms in a 12 o'clock position with the nozzles blowing air to guide the web.

(8) FIG. 8 shows a winding apparatus during winding of a web and with the retainer arms in a 3 o'clock position while placing the new core/roll.

(9) FIG. 9 shows a winding apparatus during winding of a web and with the retainer arms in a 5 o'clock position and with the new core/roll in place for winding.

(10) FIG. 10 is a perspective view of an end of the winding apparatus.

(11) FIG. 11 shows a knife unit with nozzle means.

(12) FIG. 12 shows a cross section of a crossbar/air bar with internal compartments.

DETAILED DESCRIPTION OF THE INVENTION

(13) In the following text, the figures will be described one by one and the different parts and positions seen in the figures will be numbered with the same numbers in the different figures. Not all parts and positions indicated in a specific figure will necessarily be discussed together with that figure.

(14) The FIGS. 1 to 9 all show more or less the same details, but in different stages or positions during winding, replacing the core 1 and cutting the web material 2.

(15) In FIG. 1, a winding apparatus 3 is shown during winding of a web 2 and with the retainer arms 4 in a 6 o'clock position. The various parts are mounted on a chassis 5 and comprise a winding drum 6 over which the web 2 is guided onto a roll 7 of web material 2 with the first side 8 of the web 2 towards the winding drum 6 and the second side 9 of the web 2 opposite to the first side 8. The roll 7 is rotated due to traction between said second side 9 of the web 2 and the winding drum 6 which is driven by a motor (not shown). On the retainer arm 4, a roller 10 and a crossbar/air bar 11 are shown which will be described in more detail later. Above the winding drum 6 and attached to the chassis 5, there is a carrier arm 12 that carries an empty core 1 onto which the web 2 will be wound after the roll 7 is completed. The carrier arms 12 are connected to a pivot arm 13 that comprises a knife unit 14 having cutting means 15 as well as an actuator 16 for performing a transverse movement of the cutting means 15 in relation to the web 2, the roller 10 and the cross bar 11. The actuator 16 preferably can be a pneumatic linear actuator that works at high speed.

(16) In FIG. 2, the retainer arms 4 are in a 9 o'clock position as they are rotated around the center axis of the winding drum 6 in order to prepare for a change of core 1 for a producing new roll 7 of web 2. As it can be seen, the web 2 is lifted from the surface of the winding drum 6, and thus, carried or guided on the roller 10 and the crossbar 11. The roller 10 will typically, and as indicated by its name, be rotatable, and the crossbar 11 will comprise a number of nozzles or openings for a flow of gas/air.

(17) FIG. 3 shows a winding apparatus 3 during winding of a web 2 and with the retainer arms 4 in a 12 o'clock position in preparation for a change of core 1 and roll 7. As can be seen in the figure, the web 2 is lifted from the surface of the winding drum 6.

(18) In FIG. 4, the retainer arms 4 are in a 12 o'clock position and with the carrier arm 12 in a lowered position placing an empty core 4 in position in a recess 17. At this stage, the empty core 1 is in contact with the moving web 2.

(19) FIG. 5 still shows the retainer arms 4 in a 12 o'clock position but now with lowered pivot arms, and thus, with the knife unit 14 comprising cutting means 15 and an actuator 16 in position to perform a crosswise cut of the web 2.

(20) FIG. 6 shows the next step just after cutting the web material 2, with the retainer arms 4 still in a 12 o'clock position, but now also showing the free end 20 of the web material 2 that is created by the cutting process. Further, air 18 (illustrated by cones) is ejected through nozzles 19 in the crossbar 11. As the expelled air 18 will force the free end 20 of the web 2 away from the crossbar 11, the web 2 will be blown towards the empty core 1, and thus, a new roll 7 will be started.

(21) In FIG. 7, the retainer arms 4 are still in a 12 o'clock position, but here air is blown/ejected from the nozzles 19 in the crossbar 11 as well as from additional nozzle means 21 arranged on the pivot arms 13. With all the nozzles 19, 21 blowing/ejecting air to guide the web 2 towards the core 1, a very precise winding will take place with almost no wrinkling, or even with no wrinkling of the innermost layers of the web 2. Meanwhile, the roll 7 is ejected from the winding apparatus.

(22) FIG. 8 shows the winding apparatus 3 during winding of a web 2 onto the new core 1 and with the retainer arms 4 in a 3 o'clock position while placing the core 1/roll 7 next to the winding drum 6. Here, the carrier arm 12 and the pivot arm 13 are retracted into the starting position and ready for receiving a new empty core 1 for the next change of roll 7.

(23) Finally, FIG. 9 shows the winding apparatus 3 during winding of web 2 and with the retainer arms 4 in a 5 o'clock position and with the new core 1/roll 7 in place for winding. From this position, the retainer arms 4 are moved to the 6 o'clock position shown in FIG. 1 and the winding apparatus is now ready for receiving a new empty core 1 at the carrier arm prior to the next change of roll 7.

(24) In FIG. 10, one end of the winding apparatus 3 is seen in perspective, and the position of the various parts corresponds to what is shown in FIG. 4.

(25) FIG. 11 shows a knife unit 14 with nozzle means 21 installed next to the actuator 16. These nozzle means 21 can be stationary, but can also be moved together with the cutting means 15 as the cutting means are moved across the web 2. There can also be nozzle means 21 integrated in the cutting means 15, in order to expel gas/air right next to the cutting and towards the web material 2 as indicated by flow lines in FIG. 11, i.e., the nozzles 21 will expel air directing the free end 20 of the web 2 towards the new core 1.

(26) FIG. 12 shows a cross section of a crossbar/air bar 11 with internal compartments 22. The internal compartments 22 are used as channels for a compressed gas, which typically will be atmospheric air compressed to one or more levels and guided in the internal compartments 22 to nozzles 19 in the surface of the crossbar 11. By using a different level of pressure in one or more compartments 22, the web can be guided even more directly in specific cases. One of the compartments 22 can e.g., be open towards the first side 8 of the web 2 and thus forms a recess into which the cutting means 15 can be inserted and operated along/in the cross bar 11, and to cut the web 2 while it is supported on both sides of the cut.

(27) In a preferred embodiment of the invention, the air bar 11 expels air at a first lower pressure, prior to cutting of the web. As a result, the web material is lifted slightly from the air bar 11, so that cutting of the web is performed easier and the risk of tearing the web, e.g., due to forces acting on the web material, e.g., from the rollers, is reduced. The pressure necessary for lifting the web will be slightly above the surrounding pressure, and may, e.g., be up to 1-3 bars or preferably up to 1-2 bars above the surrounding pressure. The actual value of the pressure depends on the web material, such as its density and/or thickness, whether the web is sticky or not and/or whether a single or multiple webs are rolled onto the empty core 1. Thus, the lower pressure may also be above or below the above mentioned values, if the nature of the web so requires. The air flow at the lower air pressure is applied for a period of time, i.e., the period when the air bar is in contact with the web prior to cutting. Then, an air blast at a second, higher pressure is expelled from the air bar 11 during or immediately after cutting of the web material 2 so that the free end 20 of the web 2 will be blown towards the empty core 1 as described in detail above by the air blast expelled from the air bar 11. The pressure blast necessary to blow the free end 20 of the web 2 towards the empty core 1 will be significantly higher than the lower pressure, e.g., 1-25 bars, such as 5-15 bars. The actual value of the air pressure applied during the air blast also depends on the web material, such as density and/or thickness of the web, whether the web is sticky or not and/or whether a single or multiple webs are rolled onto the empty core 1. Thus, the air blast pressure may also be above or below the above mentioned values, if the nature of the web requires so. The air blast is applied for a very short period only, e.g., up to 1-2 seconds or preferably shorter.

(28) In addition, the present invention provides means for retrofitting existing winding apparatus to adapt to the present invention, in particular to existing winding apparatus, which cuts the web from the exterior side, i.e., the second side of the web 2. When retrofitting such an existing winding apparatus, a cross bar 11 as described above can be installed in a way similarly to the present invention. It is only required, that the winding apparatus comprises an index arm 4 and a winding drum 6 mounted in a winding apparatus, in a way, which is similar to the present invention, and preferably as illustrated in FIG. 1.

(29) The invention is not limited to the embodiments described herein, and may be modified or adapted without departing from the scope of the present invention as described in the patent claims below.