Abstract:
Described is a device and a procedure to twist a coil into perforations that are provided in the margin sections of flat components, sheets of paper in particular, with a drive that causes the rotation and axial in-feed of the coil, corresponding to the inclination of its helix shape. With a stopping device the coil is inhibited from moving further and a release brings the coil out of contact with the stopping device and into contact with the drive.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the priority of German Patent Application No. 10 2004 022 246.0-26, filed on May 4, 2004, the subject matter of which is incorporated herein by reference. The disclosure of all U.S. patents and patent applications mentioned below are also incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     The invention pertains to a device for twisting a coil into perforations that are provided in the margin sections of flat components, sheets of paper in particular, with a drive that causes the rotation and axial in-feed of the coil, corresponding to the inclination of its helix shape. Furthermore the invention pertains to a procedure to twist a coil into perforations that are provided in the margin section of flat components, sheets of paper in particular, in particular using a device such as the one mentioned above.  
         [0003]     A device such as the one mentioned above is usually part of a semi or fully automatic system for the production of pads of paper that are held together with coils. In such systems sheets of paper are made of a paper web by cutting, whereupon during this production step the sheets of paper are simultaneously perforated in a margin section by means of a perforation device and imprinted in a printing machine if necessary. Afterwards these sheets of paper are overlapped and gathered into pads of a specific number of sheets of paper. Thereby the sheets of paper are stacked in such a way that the perforated margin sections are aligned to each other. The latter is important for twisting the coil through the perforations of all sheets of paper during the binding process of the paper pads in the successive binding device. The above-mentioned device and procedure are implemented in this last mentioned production step.  
         [0004]     Such a device and procedure are for example revealed in DE 1 801 965 A1. This conventional device includes three cylinders along the length of the stack of sheets of paper to be bound. Thereby the first and second cylinders are activated and run inside a protected casing, as a third cylinder with a smooth surface acts as a supporting cylinder for the coil that is driven at the periphery. The casings that contain the first and second cylinders have two functions: (i) they have to guide the coil and (ii) hold the stack of paper sheets together between the perforations to stop them from fanning out. This known device is meant for wire coils and is constructed in a relatively complicated way.  
         [0005]     U.S. Pat. No. 2,101,804 describes a similar device, that includes as well three cylinders that stretch out over the entire length of the book to be bound. Thereby two cylinders with concentrical, closed notches on their surface that run in peripheral direction, are activated, while a third cylinder with a smooth surface serves as supporting cylinder for the coil.  
         [0006]     Regarding the mechanism described above the coils are first twisted into the perforations of the pre-cut layers of paper and then cut to the desired length. However, such a procedure can lead to handling problems, in particular when using plastic coils.  
       SUMMARY OF THE INVENTION  
       [0007]     The function of the invention on hand is to improve a device and procedure of the above-mentioned kind in such a way that a trouble-free synchronized handling of coils, that are precut to a certain length, in particular plastic coils, is possible.  
         [0008]     To solve this problem it is suggested according to a first aspect of the invention that a device twists a coil into perforations that are provided in the margin sections of flat components, sheets of paper in particular, with a drive that causes the rotation and axial in-feed of the coil, corresponding to the inclination of its helix shape and characterized by a stopping device for contact with the coil to stop the coil from moving further, and a disconnecting device which brings the coil out of contact with the stopping device and in contact with the drive.  
         [0009]     Regarding a second aspect of the invention, a procedure is suggested that twists a coil into perforations that are provided in the margin sections of flat components, sheets of paper in particular, specifically by using the aforementioned device with the following steps: 
        transport a coil up to the stopping device,     bring the coil in contact with the stopping device and stop its movement,     bring the coil out of contact with the stopping device and at the same time in contact with a drive,     by using the drive, cause the rotation and at the same time an axial in-feed of the coil, corresponding to the inclination of its helix shape, and     twist the coil into the perforations of the margin sections of the stacked up flat components.        
 
         [0015]     The invention allows for the use of coils that are precut to a desired length. Thereby the stopping device that is provided by the invention assures that only one coil is handled at a time and twisted into the perforations of the stack of flat components, that is positioned on the outlet side of the machine. This is of particular advantage when using plastic coils. Thus the invention allows a synchronized twisting of coils and is especially suited for a fully automated facility. Therefore less labour is needed and the invention thus leads to an increased production.  
         [0016]     When using plastic coils the synchronized handling of coils that have been precut to the desired length has the additional advantage that the downtime due to stopping the coils with the stopping device can be used wisely for cooling down the plastic coils, because normally the plastic thread used for the previous production of helix-shaped coils has to be heated.  
         [0017]     Preferably the stopping device includes a dead stop against which the leading edge of the coil can be placed. A bar on the dead stop lying at an angle, preferably at a right angle to the moving direction of the coil, which can stand preferably and primarily in an upright position characterizing a particularly simple construction.  
         [0018]     In an extended version of the aforementioned model the disconnecting device is formed in a way that it changes the position of the coil in relation to the bar in a way that the bar lies only partly across the width of the coil, to bring the coil out of contact with the stopping device. After contact with the drive the coil can be transported onwards with the combined twisting and in-feed movement without the bar continuing to fulfill its stopping function and insofar interfering. During this operating state the bar lies in each case between two neighbouring threads of the coil. However, since it reaches only partly into the coil an interference with the opposite sections of the coil does not occur any more. So to speak the coil is ‘twisted passed’ the bar. Thus when using this model it is not necessary to disconnect the coil completely from the bar, which is an advantage regarding motion sequence and construction.  
         [0019]     Normally a transportation device leads the coil from an upstream device in which it is produced to the discussed device. Preferably such a transportation device can feature an a relatively long guide way to guide the coil in its lengthwise direction, whereby the guide way ends at the dead stop, such that the coil is advanced against the dead stop. When the dead stop features a bar the guide way should adjoin the bar at an angle, preferably at a right angle. It is practical that the guide way is formed as a relatively long guide bar across which the coil can be slid, so that the relatively long guide bar reaches through the coil and therefore the coil hangs with its inner side on the guide bar. For sufficient flexibility of the coil, namely in curved sections as well as through the disconnecting device, the thickness of the guide bar should be less and in particular considerably less than the inside diameter of the coil.  
         [0020]     Preferably the disconnecting device features a moveable component that grabs the coil to bring it out of contact with the stopping device and into contact of the drive.  
         [0021]     Another preferred model is characterized by a drive that features at least a first cylinder on whose casing the coil can be put in position and a grooved bearing with whose notches the threads of the coil can be brought into contact and by the fact that the relative position between the first coil and the bearing is changeable, to grab the coil between itself. Thus it is possible, by changing the relative position, to clamp the coil between the first cylinder and the bearing so that subsequently the drive that is twisting the coil into the perforations of stacked-up flat components by using a combined twisting and feed-in movement can come into effect.  
         [0022]     Therefore the disconnecting device should be coupled with the first cylinder and the bearing to change the relative position to each other and therewith produce the contact of the coil with the drive.  
         [0023]     Advantageously the contact element of the disconnecting device should be formed by the fist cylinder and/or the notched bearing, so that the first cylinder and/or the notched bearing insofar takes on a double function which offers constructive advantages.  
         [0024]     Preferably the notched bearing can feature at least one notched cylinder. An extended version of this model is characterized by the fact that this notched cylinder features a number of notches that are arranged in parallel to each other, arranged in a circle and notches whose distance to each other corresponds to the distance of the single windings of the helix-shape of the coil. It is insofar sufficient that the notched cylinder can be rotated freely and does not necessarily require its own drive.  
         [0025]     Preferably the notched bearing should be arranged stationary. Therefore only the first cylinder should be moveable in the direction of and away from the notched bearing.  
         [0026]     The notched bearing is basically responsible for the axial feed-in movement of the coil, because its threads are guided by the notches. Thus it is sufficient that the opposite first cylinder has a smooth surface, because it is responsible for the creation of the rotation. Therefore the first cylinder should be moved by drives in a rotating manner.  
         [0027]     In another preferred model the drive features in addition to the first cylinder at least a second cylinder, on whose casing the coil can be put in position as well and that is always arranged in a fixed relative position to the first coil, so that the first and second cylinder form a pair of cylinders to grab the coil. The first and second coil should be arranged in parallel to each other. Finally the second cylinder should be formed in the same manner as the first cylinder regarding construction and/or bearing. By arranging a second cylinder that corresponds to the first cylinder the contact with the coil is more stable. In addition such a pair of cylinders forms an advantageous arrangement to grab and support the coil, to stretch it against the notched bearing and subsequently submit it to the desired twisting movement. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]     A preferred example of the implementation of the invention is explained subsequently. The following figures show:  
         [0029]      FIG. 1  schematically with a longitudinal section the relevant components of a device for twisting a coil according to a preferred example of the implementation of the invention;  
         [0030]      FIG. 2 a  partially dissected view in relation to  FIG. 1  rotated by 90°; and  
         [0031]      FIG. 3   a  schematically a cross-section of the device of  FIG. 1  in an open position as well as  
         [0032]      FIG. 3   b  schematically a cross-section of the device of  FIG. 1  in a closed position. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0033]     The device  1  shown in the figures with its essential components serves for twisting a coil  2  that was produced from a thread not shown in an upstream device which is also not shown and features a helix-shape. The coil  2  that can be seen in  FIG. 1  only schematically in a cross-section is preferably made of a plastic thread consisting of Thermoplast.  
         [0034]     A flexible feed cable  4 , that serves as a transportation device for the coil  2  leads from the above mentioned and not shown device, where the coil  2  got its helix shape, to the pictured device  1 . Thus the function of the flexible feed cable  4  is that of a guide way for guiding the coil  2 . Typically a hydraulic or pneumatic hose, whose fluid is used for other purposes, is used as feed cable  4 . Insofar the feed cable  4  takes on a double function in the shown example. As can be seen in  FIG. 1  the coil  2  is slid across the feed cable  4 , so that the feed cable  4  reaches across the coil  2  and the coil  2  hangs on the feed cable. The diameter of the feed cable  4  is noticeable smaller than the inner diameter of the coil  2  so that the coil  2  can move sufficiently in cross direction. This guarantees a trouble free movement of the coil  2  through curved sections of the feed cable  4 .  
         [0035]     As shown in  FIG. 1  the feed cable  4  adjoins with an end section  4   a  against a bar  6  where it ends. The bar  6  reaches approximately at a right angle to the lengthwise direction of the end section  4   a  of the feed cable  4  and is arranged in the device  1  in a stationary position. The bar  6  serves as dead-stop against which the coil  2  is conveyed via the flexible feed cable. Thus the bar  6  causes an interruption of the movement of the coil  2  so that the coil stops there.  
         [0036]     As shown in  FIG. 1  in conjunction with  FIG. 3   a , a first cylinder  8  and a second cylinder  9  are provided that are arranged axially parallel to each other as well as at a distance to each other and thus form a pair of cylinders. Both cylinders  8  and  9  have a cylindrical shape with a smooth casing, the surface of which has a rubber coating. Both cylinders are mounted revolvably at a base  10 , which is mounted moveably at the device  1  and can be moved by a lifting device  12 . The lifting device can move the pair of cylinders  8 ,  9  in the direction that corresponds to the lengthwise extension of the bar  6 . The first and second cylinders  8 ,  9  are aligned in a way that their axes run approximately in parallel to the lengthwise extension of the end section  4   a  of the flexible feed cable  4  that adjoins the bar  6 . Thus the pair of cylinders  8 ,  9  is moveable at a right angle to their axes through the lifting device  12 .  
         [0037]     The first cylinder  8  is coupled coaxially and torque proofed with a first reel  14 , across which an endless drive belt  16  runs. As shown especially in  FIGS. 3   a  and  3   b , in which the drive belt  16  is indicated only by “dot line, dot line” the drive belt  16  runs from the first reel  8  across a second reel  18 , that is mounted rotably on the base  10  that is moveable by the lifting device  12 ; a third reel  20 , that is mounted stationary at the device  1 ; a fourth reel  22 , that is again mounted on the moveable base  10 ; a fifth reel  24  (see  FIG. 2 ) that is coupled coaxially and torque proofed with the second cylinder  9 ; and a sixth reel  26  that is again mounted stationary at the device  1  and arranged axially parallel to and with a distance from the third reel  20 . The first to sixths reels  14 ,  18 ,  20 ,  22 ,  24 , and  26  are all adjusted axially parallel to each other as well as to the first and second cylinders  8 ,  9 . The sixth reel  26  is coupled with a drive  28  that is as well arranged stationary at the device  1 , as shown in  FIG. 1 . Thus the drive  28 , via the drive belt  16 , causes the pair of cylinders  8 ,  9  to rotate.  
         [0038]     The first, second, fourth and fifth reel  14 ,  18 ,  22  and  24  are arranged with their axes at the corners of an imaginative rectangle while the third and sixth reel  20  and  26  are arranged within this imaginative rectangles among one another and therefore lengthwise to the imaginative rectangle. The result of this special arrangement is that with the aid of the lifting device  12  the base  10 , on which the first, second, fourth and fifth reel  14 ,  18 ,  22  and  24  are mounted can be shifted between two final positions without having to change the actual length of the drive belt  16 . In fact the drive belt  16  is always tightened in this arrangement so that a rotation of the first and second reels  8 ,  9  with a switched on drive  28  is guaranteed independently of the lift position of the base  10 .  
         [0039]      FIG. 3   a  shows a first final position of the base  10 , in which the pair of cylinders  8 ,  9  is in a position distant from the feed line and therefore from the coil  2 . In contrast  FIG. 3   b  shows the base  10  in its second final position, in which the pair of cylinders is in its position neighbouring feed line  4 . Since in the example shown the base  10  is moveable in vertical direction by the lifting device  12 , the first final position shown in  FIG. 3   a  is a lower lifting position and the final position in  FIG. 3   b  an upper lifting position.  
         [0040]     As  FIG. 3   b  also shows the bar  6  is located between the first cylinder  8  and the second cylinder  9 . Thus it is possible that the pair of cylinders  8 ,  9  can move in direction of the lengthwise extension of the bar  6  without colliding with the latter.  
         [0041]     A third cylinder is arranged at a distance from the pair of cylinders  8 ,  9  as a notched cylinder  30  that is aligned axially parallel to the first and second cylinder  8 ,  9 . The notched cylinder  30  has on its outer surface or its casing respectively a number of concentrically circumferential closed notches  32 . Thereby in each case the distance between two neighbouring ring-shaped notches  32  is constant and corresponds to the inclination of the coil&#39;s helix-shape. Thus each notch  32  grabs in sections a thread of the coil. The notched cylinder  32  is mounted rotably on a bearing element  34  at the device  1 . Normally the notched cylinder  30  is arranged stationary during operation. In the example shown, as especially shown in  FIG. 2 , the bearing element  34  is formed as a bracket and can be arranged swivel-mounted at the device  1 . Thus it is possible to swivel the notched cylinder  30  out of the way for maintenance or exchange.  
         [0042]     When the pair of cylinders  8 ,  9  is lifted with the aid of the lifting device  12  from their lower first setting as shown in  FIG. 3   a  to their upper second setting as shown in  FIG. 3   b , the pair of cylinders comes into contact with the coil  2  that still adjoins the bar  6  with its preceding section. Thus the coil  2  lies on the pair of cylinders  8 ,  9 . With continuous upwards lifting movement the pair of cylinders  8 ,  9  picks up the coil  2  so that it does not hang any more at the end section  4   a  of the flexible feed line  4 , as shown in  FIG. 3   a . Instead it is disconnected and lifted by the feed line as shown in  FIG. 3   b . When the pair of cylinders  8 ,  9  reaches its upper second position as shown in  FIG. 3   b , the coil that lies on the pair of cylinders  8 ,  9  at the same time comes into contact with the above lying notched cylinder  30 , because the sections of the single windings are gathered by the notches  32 . Thus the coil  2  is clamped between the first and second cylinders  8 ,  9  and the notched cylinder  30 . This state cannot only be seen in  FIG. 3   b  but also in  FIG. 1  in an illustration of the coil in uninterrupted lines that are marked with the reference symbol  2 . 1 .  
         [0043]     At the latest when the pair of cylinders  8 ,  9  has reached its upper second position as shown in  FIGS. 1 and 3   b  the drive  28  is switched on, causing the pair of cylinders  8 ,  9  to rotate. Thus the coil  2 . 1  is put into rotation as well, because between the first and the last cylinders  8 ,  9  and the coil, whereas the coil  2 . 1  at the same time takes on an axial in-feed corresponding the inclination of its helix shape. Since the coil  2 . 1  has been lifted with the upward moving pair of cylinders  8 ,  9  unlike the bar  6 , the bar  6  does not reach any more across the total cross section of the coil  2  but only partly. Since the coil  2  has been lifted up by the cylinder pair  8 ,  9  compared to the bar  6  the bar does not reach any more across the entire section of the coil  2 , but only partly. This is clearly shown in  FIG. 1  by a comparison between the coil  2  that is shown as a cross section and the lifted coil  2 . 1  that is shown in a solid line. Thereby the coil overcomes the bar  6  when set into rotation by the pair of coils  8 ,  9 . Since the bar  6  in this way interferes only on one side (as shown in  FIG. 1  lower) of the coil  2 . 1 . Between its threads the coil  2  screws along the bar  6 , whereby the bar  6  looses its function as a dead stop.  
         [0044]     For the sake of completeness, it has to be mentioned that the first and second cylinder  8 ,  9  together with the notched cylinder  30  form a so-called three-jaw chuck in the closed state, when the cylinder pair  8 ,  9  is located in the second upper position as shown in  FIG. 3   b.    
         [0045]     As shown in  FIG. 2  the coil  2 . 1  is twisted into a number of perforations  36  that are pre-cut in a margin section  38   a  of a stack of paper  38  after it left the notched cylinder  30  and thereby also the pair of cylinders  8 ,  9 . Thereby the stack of papers  38  with its margin section  38   a  is aligned accordingly to the first and second cylinders  8 ,  9  and the notched cylinder  30 .  FIG. 1  shows as well that on the outside of the notched reel  30  an opposite notched reel  40  is allowed for additional support in feeding into the perforations  36 .  
         [0046]     At last it should be mentioned that the shown device  1  is suited very well for the application of coils  2  with varying inclinations and/or diameters. In this case only the notched cylinder  30  and the notched cylinder  40  have to be replaced accordingly.  
         [0047]     The invention has been described in detail with respect to preferred embodiments, and it will now be apparent from the foregoing to those skilled in the art, that changes and modifications may be made without departing from the invention in its broader aspects, and the invention, therefore, as defined in the appended claims, is intended to cover all such changes and modifications that fall within the true spirit of the invention.