METHOD AND APPARATUS FOR SPLICING AT LEAST TWO SINGLE OR MULTIPLE LAYER MATERIALS COMPRISING AIR PERMEABLE SOFT PAPER WEBS

Abstract: The invention relates to a method and apparatus for splicing at least two single or multiple layer materials comprising air permeable soft paper webs while retaining web tension during operation. The apparatus includes a first suction chamber (5) for retaining an end portion (3) of a new web (2) in trailing engagement against the first web (1) which is to be spliced, a second suction chamber (4) over which moves the web (1), which is to be spliced, as well as the forward end portion (3) of the new web (2) for splicing, a regulatable vacuum system for the suction chambers (4, 5), en embossing nip (6) placed downstream of the second suction chamber (4) for bonding together the webs (1, 2) kept together with the aid of controlled air passage through them, and a cutting means (7) for cutting off the moving web (1). Splicing takes place by vacuum changes in both suction chambers (4, 5) arranged at the webs (1, 2) for entraining the end portion (3) of the new web (2) to the web (1) which is to be spliced in the embossing nip (6), where bonding of both material webs takes place such as to form a reliable splice, subsequent to which the moving web (1) is cut off for completing the splicing operation.

Description: Method and Apparatus for splicing at least two single or multiple layer materials comprising air permeable soft paper webs The present invention relates to a method and apparatus for splicing at least two single or multiple layer materials comprising air permeable soft paper webs. An usual method of splicing web material has so far been to stop the material web which is to be spliced and thereafter to manually tape the old material web to a new. For pro¬ viding a more secure splice between two multiple layer materials it is usual to tape both sides of the departing material web so that the upper and lower layers of the respective material web are joined together. A natural result of this splicing method is that the web tension, which is important for carrying out the process, is lost. Starting up again after splicing and retrieving the web tension results in undesired material waste. Another method used for simple material webs has been to use vacuum for providing a temporary positional fixation of the new mate¬ rial web in relation to the old one which is to be spliced, the speed of the web which is to be spliced being lowered at a predetermined splicing instant sufficiently for the new material web to be fixed against the old one with the aid of rapidly setting glue or a tape arrangement when the webs come together and the vacuum is released. This method has been found unsuitable for thin multiple layer soft paper material due to only one of the layers in the respec- tive material web being joined to each other. One object of the present invention is to achieve a method and apparatus for splicing soft paper webs in particular, the above mentioned drawbacks having been completely elimi- nated while the material waste at the splice location is very small. The features characterizing the invention are disclosed in the accompanying claims. There has now been provided in accordance with the inven- tion a method and apparatus for splicing at least two single or multiple layer materials comprising air permeable soft paper webs, where the splicing itself can be carried out without additional material and continuity of the web feed during operation can be maintained for subsequent operations at the same time. The invention will now be described in more detail below, with reference to the accompanying drawings, where Fig- l schematically illustrates a preferred embodiment of an apparatus for carrying out the method in accor¬ dance with the present invention, Fig. 2 schematically illustrates an alternative embodiment of an apparatus for carrying out the method in accordance with the invention and Fig. 3 schematically illustrates a third embodiment of an f apparatus for carrying out the method in accordance with the present invention. In figure 1 there is shown a preferred, first embodiment of a splicing apparatus in accordance with the present inven¬ tion, where a roll stand 10 is formed for carrying two rotatably mounted material rolls 11, 12. Associated with the rolls n, 12 there is a web fixation moans 16, in juxtaposition with an embossing nip 6, after which there is arranged a paper buffer store 17 with at least one balanc¬ ing means 18. The web fixation means 16 includes a first suction chamber 5 for retaining an end portion 3 of a new web 2 so that the end portion 3 can trail against the web 1, which is to be spliced. This web 1 extends over a second suction chamber 4, over which also trails the out¬ most portion 8 of the end portion 3 trailing against the web 1. In addition, there is an unillustrated regulatable vacuum system for the suction chambers 4 and 5. The emboss¬ ing nip 6 is placed downstream of the second suction cham¬ ber 4 for- joining the webs 1 and 2, which are kept together with the aid of controlled air passage through them. Close to the web 1 which is, to be joined, there is a cutting means 7, e.g. in the form of a pneumatically driven, trans- versally moving knife for cutting the web 1 after the splicing operation. Splicing the material web 1 and 2 is performed in the following manner. Splicing in a new material web 2 from a roll 12 on the roll stand 10 is prepared by the forward end portion 3 of the new web 2 being placed over the material web 1 coming from the roll 11, and which is to be replaced. The end portion 3 is now positionally fixed with the aid of vacuum from the first suction chamber 5. In this position the outmost part 8 of the end portion 3 trails against the moving web 1 over a region 9 associated with the second suction chamber 4. Certain web materials which glide against each other generate static electricity, resulting in that the material surfaces are attracted to each other. A soft paper web in the form of a multiple layer tissue which is to be processed should suitably be conditioned to a moisture value in the material counteracting the genera- tion of static electricity. In order to achieve a material- tensioning friction force between both material webs 1 and 2, a controlled air flow can be utilized, this air flow passing through the material webs towards the suction chamber 4. Positional fixation of the new material web 2 takes place by its being kept fixed against the first suction chamber 5, situated above and close to the new- material web 2 and in close association with the underlying suction chamber 4. The outmost part 8 of web 2 is in this position at a safe distance from the embossing nip 6, which comprises embossing rolls 13 and 14. The actual splicing operation takes place in the following manner. The roll 11 with the web which is to be replaced is braked to a lower speed and web material will move out from a material buffer store 17, so that the web tension can be maintained unal- tered, this being possible by an upper roll set 15 in the store 17 moving downwards. At a given signal the rolls 13 and 14, now running synchronously with the web fixation means 16. are urged together in the embossing nip, the suction force in the suction chamber 4 being increased simultaneously as the regaining force in the first suction chamber 5 ceases and the new roll 12 is started up by a drive means not illustrated on the drawing. When the out-* most part 8 of the end portion 3 of the web 2 passed in between the embossing rolls 13 and 14 together with the old material web 1, this web is cut off by the cutting means 7 which includes the pneumatically driven transversally moving knife. The splicing sequences is carried out in a couple of seconds, and for this reason the length of the double multiple layer material in the embossed splice is limited. If a process machine is automatically regulated to a lower speed in connection with splicing, full control of web tension as well as the register of printing and border embossing can be maintained. Figure 2 illustrates an alternative embodiment of a splic¬ ing apparatus for carrying out the method in accordance with the present invention. Shown here are the new web 2 and the web 1, which are to be spliced, both these webs coming from rolls not shown on the drawing. In this example a suction chamber 4 is arranged inside a drum 19 within its cylindrical surface 20 and the embossing nip 6 is formed between this drum 19 and the embossing roll 14. Downstream of the roll nip 6 there may be a paper buffer store with counterweight means as in the first embodiment. The described splicing technique for air permeable single or multiple layer materials can also be applicable to rolling off from rolls with web ruptures to rolls where the webs have received overlapped, embossed fixation splices, and in figure 3 there is shown a third embodiment of an apparatus for carrying out the splicing method in according with the present invention. Here it is assumed that the rolling-off station includes at least two rolling off positions, i.e. rolls 11, 12, and that the web rupture locations are indicated by marking one or both end sides of either roll 11, 12, or that the web rupture positions are given as a number of meters or roll turns from the instant the material starts to be taken from either of the rolls 11, 12. Due to the present invention there is no principle difficulty in the number of ruptures per roll being more than one, providing information as to the number of rupt¬ ures and their locations are suitable defined, e.g. by a bar code on the content description of the respective roll 11, 12. When a rupture in the web on the first, rotating roll 11 in figure 3 is signalled, it has been assumed that the splice has been prepared for the second roll 12, from which the web 2 extends and is retained with the aid of a first suction chamber 5 so that the outmost part B of the end portion 3 of the web 2 t ains against moving web 1. Immediately prior to the rupture location the splice is made automatically by speed restriction and, by increased vacuum in the suction chamber 4, increasing the trailing pressure for the new web 2, full extension thus being obtained as well as optimum traction force for the new web 2 together with web :. Webs 1 and 2 are now embossed when they come into the enbossing nip 6, subsequent to which the old web 1 is cut off. Preparations are then made immediate- ly for splicing the web 2 coming from the roll 12. Carrying out the above mentioned technique assumes that the number of suction chambers 4 is doubled such that there is one for each material web 1 and 2, so that drawing in to the common embossing nip 6 can be carried out for the two webs 1 , 2 lying one above the ether. The suction chamber 4 which is not used can be swung to one side, or swung upwards from the webs 1 , 2 in some suitable manner, not illustrated on the drawing. Tne technique is however the same as applies for splicing at the end of a roll, i.e. that the suction chamber 4 is placed along the material web which is to be spliced according to the embodiment described first. In the case where the invention is applied to air permeable material webs, and these include layers or constituents which will stick together when warm, bonding together in the embossing nip 6 of both webs 1, 2 can be achieved with the aid of heat, and this can be transmitted to the web material, e.g. by one of the rolls 13, 14; 19 forming the embossing nip 6.

Claims: CLAIMS 1. Method of splicing at least two single or multiple layer materials comprising air permeable soft paper webs 5 while maintaining unaltered web tension during operation, characterized in that splicing of a new web f2 to a moving web (1) is prepared by the forward end portion (3) of the new web ( 2 > being positionally fixed with the aid of vacuum in a manner known per se against a first suction chamber " •0 (5) f 0r retaining the end portion (3) in a position with an outmost part (6) cf the end portion (3) of the web (2) trailing against the moving web (1 ) at a second suction chamber (4) over which the web (1) passes, a suction force in the form of a controlled air flow through both material " ■5 webs (1, 2) being generatable with the aid of this suction chamber (4), and in that for a splicing instant the suction force in the second suction chamber (4) is actuated for full entraining effect simultaneously as the suction force in the first suction chamber (5) is released, the departing 0 web (1) taking with it the new web (2), by reason of the vacuum in the second suction chamber (4), into the emboss¬ ing nip (6) now activated to its embossing setting, subse¬ quent to which the moving web (l) is cut off for completion of the splicing operation. 5 2. Apparatus for splicing at least two single or multiple layer materials cc-prising air permeable soft paper webs while maintaining web tension during operation, charac¬ terized in that it includes a first suction chamber (5) for 0 retaining an end portion (3) of a new web (2) such as to provide trailing engagement against the web (l) which is to be spliced, a second suction chamber (4) over which the web (1) for splicing moves, and over which the forward end portion (3) of the new web (2) also trails before splicing, a regulatable vacuum system for the suction chambers (4, 5), an embossing nip (6) placed downstream of the second suction chamber <4) for bonding together the webs d, 3) kept together with the aid of controlled air passage through them, and a cutting means (7) for cutting off the moving web (1) . 3. Apparatus as claimed in claim 2, characterized in that the embossing nip (6) includes at least two opposing em¬ bossing rolls (13, 14; 19) of which at least one is heat- able.

Inventors: ANDERSSON KARL GOESTA BERTIL, ANDERSSON, KARL, GOESTA, BERTIL
Applicants: DUNI AB
Application year: 1991
Main classification: B65H19
IPC codes: B65H19