Method and apparatus for tail threading of a paper web in a finishing machine for paper

Abstract

A device in a finishing machine for paper is arranged to guide a paper web along a predetermined path. The traction device ( 2 ) engages a tail of the web or an auxiliary member ( 6 ) for transferring the tail of the web. The device has power transmission of its own by means of which is moves in relation to a guide ( 1 ) extending in the machine direction. The traction device moves in relation to the guide by friction contact of one or several drive wheels ( 3 ) with the guide ( 1 ). The friction contact plane of the guide ( 1 ) curves in directions perpendicular thereto in accordance with the travel path of the paper web.

1 - 31 . (canceled)  
     
     
         32 . A method for tail threading of a paper web in a finishing machine for paper that is arranged to guide a paper web along a predetermined path, the method comprising the step of drawing a tail of the web or an auxiliary member for threading the tail of the web with a traction device comprising power transmission of its own by which the traction device moves in relation to a guide extending in the machine direction, wherein the movement of the traction device in relation to the guide is attained by a friction contact of one or several drive wheels of the traction device with the guide, and wherein the guide has a friction contact plane which curves in directions perpendicular thereto in accordance with the travel path of the paper web.  
     
     
         33 . The method of  claim 32 , wherein, in threading, one or several successively coupled carriages are used as the traction device, said carriages being articulated to turn with respect to each other in the plane of curvature of the guide, wherein said one or several drive wheels are located in a different carriage than the fastening point of the tail of the web or the auxiliary member for threading the tail of the web.  
     
     
         34 . The method of  claim 33 , wherein three or several successively coupled carriages are used, which are articulated to turn with respect to each other in the plane of curvature of the guide, and in which at least a power source is positioned in a carriage of its own.  
     
     
         35 . The method of  claim 34  wherein the power source comprises a battery.  
     
     
         36 . The method of  claim 32  wherein a pressing force of the one or several drive wheels is attained by counter wheels effective on an opposite side of the friction contact plane of the guide.  
     
     
         37 . The method of  claim 32  wherein the friction contact is attained by means of a belt passed around at least one drive wheel.  
     
     
         38 . The method of  claim 32  wherein in the tail threading of the web a lead-in strip that is narrower than the full-width web is first transferred at least to a section of predetermined length in the machine direction of the finishing machine, whereafter the lead-in strip is followed by a full-width web.  
     
     
         39 . The method of  claim 32  wherein the predetermined path contains at least one hold point capable of transferring the tail of the web at a predetermined transfer rate irrespective of the traction device, and the transfer rate of the hold point of the finishing machine and the travel speed of the traction device along the guide are adjusted with respect to each other in such a manner that the tail of the web drawn with the traction device travels substantially at the transfer rate of the hold point.  
     
     
         40 . The method of  claim 39  wherein the tail of the web comprises a lead-in strip which is directly connected to the traction device.  
     
     
         41 . The method of  claim 32  wherein the tail of the web is transferred simultaneously with the movement of the traction device and drawn with the traction device via the auxiliary member that transmits tensile stress.  
     
     
         42 . The method of  claim 39  wherein the tail of the web is drawn in the drawing direction with an elastic auxiliary member.  
     
     
         43 . The method of  claim 32  wherein by means of the traction device the auxiliary member, which transmits tensile stress, is first drawn at least to a section of predetermined length in the machine direction of the finishing machine without a drawing contact to the tail of the web, and thereafter the tail of the web is drawn on the same section by means of the auxiliary member transmitting tensile stress.  
     
     
         44 . The method according of  claim 32  wherein the guide is utilized to guide the traction device, and with said traction device the tail of the web and/or the auxiliary member, at least partly via a winding path that contains sections curved in opposite directions.  
     
     
         45 . The method of  claim 32  wherein the guide is utilized to guide through at least one coating station the traction device, and with said traction device the tail of the web and/or the auxiliary member.  
     
     
         46 . The method of  claim 32  wherein the guide is utilized to guide through at least one calendering nip the traction device and with said traction device the tail of the web and/or the auxiliary member.  
     
     
         47 . The method of  claim 32  wherein the guide is utilized to guide from an unwinder through the entire finishing machine to a reel-up, the traction device and with said traction device the tail of the web and/or the auxiliary member.  
     
     
         48 . The method of  claim 32  wherein the tail comprises a lead-in strip which is spread into a full-width web at the same time as it is drawn by the traction device.  
     
     
         49 . The method of  claim 32  wherein the guide is cooled down by a cooling medium at least for a part of its length.  
     
     
         50 . The method of  claim 32  wherein the speed of the traction device is adjusted during threading by remote control.  
     
     
         51 . The method of  claim 32  further comprising the step of measuring the force affecting the fastening point of the tail of the web or the auxiliary member in the traction device during threading.  
     
     
         52 . An apparatus for tail threading of a paper web in a finishing machine for paper, in which the paper web is arranged to travel along a predetermined path, wherein the apparatus comprises a threading device comprising a guide extending in the machine direction, as well as a traction device for the tail of the web that is arranged to move along and in relation to the guide, said traction device comprising a drive wheel connected to the power transmission of the traction device itself, said drive wheel being arranged to transfer the traction device in relation to the guide by means of a power transmitting contact between the guide and the drive wheel, and wherein the drive wheel is arranged in a friction contact with a friction contact plane of the guide and the friction contact plane of the guide curves in directions perpendicular thereto in accordance with the travel path of the paper web.  
     
     
         53 . The apparatus of  claim 52  wherein the guide comprises an elongated profile having an outer surface which the drive wheel contacts.  
     
     
         54 . The apparatus of  claim 53  wherein the elongated profile comprises a flat bar.  
     
     
         55 . The apparatus according to  claim 53 , wherein the traction device comprises counter wheels positioned against the surface of the profile on an opposite side of the profile with respect to one or several drive wheels.  
     
     
         56 . The apparatus of  claim 55  wherein one or several drive wheels and the counter wheels are connected to different frame parts attached together to move with respect to each other in a direction perpendicular to the friction contact plane of the guide.  
     
     
         57 . The apparatus of  claim 52  wherein the traction device contains two or several successively coupled carriages that are articulated to turn with respect to each other on the plane of curvature of the guide, and in which the drive wheel or drive wheels and a fastening point of the tail of the web or the auxiliary member are located in different carriages.  
     
     
         58 . The apparatus of  claim 52 , wherein the traction device comprises three or several successively coupled carriages that are articulated to turn with respect to each other on the plane of curvature of the guide, and in which at least a power source is positioned in a carriage of its own.  
     
     
         59 . The apparatus of  claim 57  wherein the power source comprises a battery.  
     
     
         60 . The apparatus of  claim 52 , wherein a belt is passed around at least one drive wheel, said belt forming a loop that is arranged in a friction contact with the guide.  
     
     
         61 . The apparatus of  claim 52  wherein the traction device comprises a drive motor which is an electrical motor.  
     
     
         62 . The apparatus of  claim 52  wherein the speed of rotation of the drive wheel of the traction device is adjustable.  
     
     
         63 . The apparatus of  claim 62  wherein the speed of rotation of the drive wheel of the traction device is adjustable in a stepless manner.  
     
     
         64 . The apparatus of  claim 62 , wherein the speed of rotation of the drive wheel of the traction device is adjustable by remote control.  
     
     
         65 . The apparatus of  claim 52  wherein the traction device comprises a power measurement sensor in a fastening point of the tail of the web or the auxiliary member.  
     
     
         66 . The apparatus of  claim 52  wherein the guide comprises a channel for a cooling medium.  
     
     
         67 . An apparatus for tail threading of a paper web in a finishing machine for paper, in which the paper web is arranged to travel along a predetermined path, the apparatus comprising: 
 a guide which extends in a machine direction, and which has a friction contact plane, the guide extending along a curved path which curves in both directions in a direction perpendicular to its plane in accordance with the windings of the path;    a traction device comprised of a plurality of carriages, which are arranged to move along and in relation to the guide, wherein a first one of said plurality of carriages comprises a drive wheel connected to a power transmission of the traction device, the drive wheel being arranged to transfer the traction device in relation to the guide by means of a power transmitting contact between the guide and the drive wheel, wherein the drive wheel is arranged in a friction contact with the friction contact plane of the guide, wherein the friction contact plane of the guide curves in directions perpendicular thereto in accordance with the travel path of the paper web; and    wherein a tail of the paper web or an auxiliary member for threading the tail of the paper web is connected to one of said plurality of carriages.