Abstract:
A method of threading a fiber web tail movable in a machine direction, comprising the steps of: positioning a threading arm assembly in association with a rope nip, the threading arm assembly including a frame and a diverter carried by and movable relative to the frame; diverting the tail using the threading arm assembly in a direction transverse to the machine direction toward the rope nip; and threading the diverted fiber web tail into said rope nip.

Description:
This is a division of U.S. patent application Ser. No. 10/278,296 entitled “THREADING ARM ASSEMBLY FOR A PAPER MACHINE”, filed Oct. 23, 2002. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to paper machines, and, more particularly, to devices for threading a fiber web tail in a paper machine. 
     2. Description of the Related Art 
     During startup of a paper machine, or following a web break, a narrow edge strip of the fiber web (called a tail) is typically guided along a web travel path through the dry end of the machine. Blast nozzles pointing in the machine direction may be used to transfer the tail through the machine. The air jets produced by the blast nozzles drive the tail in the desired direction through the machine. This process is known as “threading ”the machine. 
     It is known to provide a rope guide arrangement whereby two points converge in a so called rope nip at the beginning of the rope guide arrangement. The tail is led into the rope nip which is located in a pick up area and is held between the ropes. The tail is carried together with the ropes along the web travel path into a transfer area in which the tail is transferred to a downstream unit in the machine. 
     Occasionally, the tail may not align with the rope nip defined by the rope guide arrangement. It is sometimes necessary to manually feed the tail into the rope nip for threading of the machine. Not only is this time consuming, but it is also desirable to avoid inserting hands and arms into the machine area whenever possible. 
     What is needed in the art is a device which not only threads a fiber web tail in a machine direction, but also is capable of diverting the fiber web tail in a direction transverse to the machine direction. 
     SUMMARY OF THE INVENTION 
     The present invention provides a threading arm assembly which diverts a fiber web tail laterally (with respect to the machine direction). 
     The invention comprises, in one form thereof a paper machine for manufacturing a fiber web traveling in a machine direction and having a tail. At least one rope defines a rope nip. A threading arm assembly is positioned in association with the rope nip. The threading arm assembly includes a frame and a diverter carried by the frame. The diverter is movable to divert the tail in a direction transverse to the machine direction toward the rope nip. 
     The invention comprises, in another form thereof a threading arm assembly for threading a fiber web tail. The threading arm assembly includes a frame having a mounting, and a diverter carried by the frame. The diverter is movable generally toward the mounting for diverting the fiber web tail generally toward the mounting. 
     An advantage of the present invention is that the fiber web tail can be diverted laterally into a rope nip associated with a dryer section. 
     Another advantage is that the diverter can be provided with an air cushion so as not to directly contact the fiber web tail. 
     Yet another advantage is that the diverter can be operated either manually or automatically. 
     Still another advantage is that the threading arm assembly of the present invention can be retrofitted to existing machines. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of an embodiment of a threading arm assembly of the present invention; 
         FIG. 2  is a side view of the threading arm assembly of  FIG. 1 ; 
         FIG. 3  is a side view of another embodiment of a threading arm assembly of the present invention; 
         FIG. 4  is a side view of the threading arm assembly of  FIG. 3  with the diverter in a pivoted position; 
         FIG. 5  is a side view of vet another embodiment of a threading arm assembly of the present invention; 
         FIG. 6  is a schematic view of a portion of a paper machine, showing relative placement of a threading arm assembly of the present invention; and 
         FIG. 7  is a schematic view of a portion of another paper machine, showing relative placement of a threading arm assembly of the present invention. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate one preferred embodiment of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and more particularly to  FIGS. 1 and 2 , there is shown an embodiment of a threading arm assembly  10  of the present invention used for threading a fiber web tail in a paper machine. Threading arm assembly  10  is positioned in association with a rope nip, such as associated with a drying section in the paper machine, for threading the fiber web tail into the rope nip. Threading arm assembly  10  generally includes a frame  12 , elongate member  14 , diverter  16  and air assist tube  18 . 
     Frame  12  is positioned along a side of the paper machine and attached to any suitable structure. Frame  12  includes a mounting  20  in the form of a plate with mounting holes therein. Mounting  20  allows threading arm assembly  10  to be mounted to new paper machinery or retrofitted to existing paper machinery. Other types of mountings are of course also possible, depending upon the particular application. 
     Elongate member  14  is in the form of a cylindrical tube which is carried by frame  12 . Cylindrical tube  14  is both longitudinally moveable as well as rotatable relative to frame  12 . A handle  22  is attached to cylindrical tube  14  to manually slide and rotate tube  14  relative to frame  12 . An adjustable stopper  24  is attached to tube  14  and limits manual movement of tube  14  relative to frame  12 . 
     An adjustable plate assembly  26  is attached to the distal end of cylindrical tube  14 . Plate assembly  26  includes a first plate  28  attached to cylindrical tube  14 , and a second plate  30  adjustably attached to first plate  28 . Suitable fasteners, such as bolts (not show), are placed within the slotted openings formed in each of first plate  28  and second plate  30  to provide adjustability therebetween. 
     Diverter  16  is connected with second plate  30  using adjustable bushings  32  providing both longitudinal as well as rotational adjustability. Diverter  16  is placed at a desired orientation within bushings  32 , and locked into place such as with set screws or the like. 
     Diverter  16  has a generally C-shaped cross section. Diverter  16  also has a hollow interior which is in fluid communication with a plurality of air discharge holes  34  at the inner portion of the C-shaped cross section. Air discharge holes  34  generally face toward frame  12 . The hollow interior portion of diverter  16  is fluidly connected with hollow tube  14  by a fluid line  36 , which in turn is connected with a source of pressurized air at the opposite thereof (not shown). 
     Air assist tube  18  is also carried by frame  12 , and includes a plurality of air discharge holes  38 . When in an operating position as shown in  FIG. 2 , fiber web tail  40  passes between cylindrical tube  14  and air assist tube  18 , and moves from left to right as indicated by arrow  42 . Air assist tube  18  is coupled with a suitable source of pressurized air, such as the same source to which cylindrical tube  14  is coupled. 
     During periods of inoperation, cylindrical tube  14  is rotated and retracted such that diverter  16  is rotated upwards and retracted to a position adjacent frame  12  so as not to interfere with operation of the traveling fiber web. If it becomes necessary to thread a fiber web tail, the tail is passed over air assist tube  18  and is urged in the machine direction by the plurality of air discharge holes  38  therein. Cylindrical tube  14  is manually slid to an extended position with handle  22 , and rotated downwardly such that diverter  16  is adjacent to the distal end of air assist tube  18 . Cylindrical tube  14  is positioned such that the side edge of the fiber web tail passes generally through the inner C-shaped portion of diverter  16 . Handle  22  is then pulled in an axial direction to cause diverter  16  to move toward the edge of the fiber web tail. Continued retraction of cylindrical tube  14  and diverter  16  moves the fiber web tail in the transverse direction with respect to the machine or running direction  42 . 
     Referring now to  FIGS. 3 and 4 , there is shown another embodiment of a threading arm assembly  50  of the present invention. In the embodiment shown in  FIGS. 3 and 4 , fiber web tail  40  is traveling in a direction perpendicular to the drawing page. Threading arm assembly  50 , like threading arm assembly  10  shown in  FIGS. 1 and 2 , moves fiber web tail  40  in a transverse direction with respect to the running or machine direction. However, rather than using a C-shaped diverter with an air cushion as shown in  FIG. 1 , threading arm assembly  50  includes a pivot arm  62  which pivots as shown by arrow  52  in  FIG. 4 , thereby causing movement of fiber web tail  40  in a direction transverse to the machine direction as indicated by arrow  54 . 
     More particularly, threading arm assembly  50  includes a mounting  56  which is pivotally coupled with a pivot linkage  58  at pivot pin  60 . Pivot arm  62  has a pre-selected length and is in threaded engagement with pivot linkage  58 . Pivot linkage  58  has a generally L-shaped configuration, with the free end being coupled with a pneumatic cylinder  64 . Pneumatic cylinder  64  is a two way cylinder in the embodiment shown, which is either manually or remotely actuatable. Pneumatic cylinder  64  is of course fluidly coupled with a source of pressurized air (not shown). 
       FIG. 5  illustrates yet another embodiment of a threading arm assembly  70  of the present invention. Similar to the embodiment of threading arm, assembly  50  shown in  FIGS. 3 and 4 . threading arm assembly  70  shown in  FIG. 5  has a pivot arm  72  which is pneumatically actuated. However, rather than pivoting in an upward direction as shown in the embodiment of threading arm assembly  50 , pivot arm  72  pivots in a downward direction to move the fiber web tail in a transverse direction with respect to the running direction into ropes  74 . Pivot arm  72  may also pivot in an upward direction, depending on the specific application. 
     More particularly, threading arm assembly  70  includes a frame  76  which is pivotally coupled with pivot arm  72  at pivot pin  78 . A pneumatic cylinder  80  is also carried by frame  76 . Pneumatic cylinder  80  is a single action, spring loaded air cylinder which pivots pivot arm  72  in a downward direction as shown by phantom line  82  when actuated. An internal spring biases pivot arm  72  to the position shown when pneumatic cylinder  80  is in a non-actuated state. 
     Stroke cylinder  84  is a pneumatic cylinder which moves frame  76  and pivot arm  72  between operable and non-operable positions. Stroke cylinder  84  is a 2-way cylinder having a guide member  86  which extends therefrom. Frame  76  is coupled with the distal end of ram  90  within stroke cylinder  84 . Guide pin  88  extending from frame  76  extends through an opening formed in guide member  86 , and maintains the relative positioning between frame  76  and stroke cylinder  84  during extension and retraction of ram  90 . Stroke cylinder  84  is coupled with and carried by suitable structure on the paper machine, such as a frame member, etc. 
       FIG. 6  is a schematic view of a portion of a paper machine  100 , showing relative placement of a threading arm assembly  102  of the present invention. Threading arm assembly  102  could be any of threading arm assemblies  10 ,  50  or  70  described above, depending upon the particular application. Paper machine  100  includes a press assembly  104  and a dryer cylinder  106 . Press assembly  104  includes two press rolls defining a nip therebetween. A felt  108  passes through the press nip formed by press assembly  104  between the two roles, and carries fiber web tail  110 . Fiber web tail  110  passes over threading arm assembly  102  and thus it is assumed that threading arm assembly  102  is configured as threading arm assembly  10  or threading arm assembly  50  described above. It will be appreciated, however, that threading arm assembly  102  may likewise be positioned above tail  110 , in which case it may take the form of threading arm assembly  70 . Regardless of the particular configuration, threading arm assembly  102  moves tail  110  in a transverse direction with respect to machine direction  112  to thread tail  110  into ropes  114  and  116 . 
       FIG. 7  is a schematic view of a portion of another embodiment of a paper machine  120 , showing relative placement of a threading arm assembly  122 . Paper machine  120  includes a center press roll  124 , vacuum box  126 , baby dryer cylinder  128 , felt  130  and ropes  132 ,  134 . Again, threading arm assembly  122  may take the form of threading arm assembly  10 ,  50  or  70 , depending upon the particular application. Threading arm assembly  122  diverts the fiber web tail in a transverse direction with respect to machine direction  136  into the nip formed between ropes  132  and  134 . 
     While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.