Abstract:
An apparatus is provided for automatically trimming three open side edges of printed products bound along a fourth edge to a desired format for each printed product. The printed products are transported in a transport direction along a surface of a trimming table. First, second and third trimming stations are located one after the other in the transport direction along the trimming table. Each trimming station includes a trimming device having at least one stationary blade that can be driven in a plane extending perpendicular to the surface of the trimming table, a positioning device for positioning one of the open side edges of a respective printed product on the trimming table to be cut, and a pressing device, with which a respective positioned printed product can be pressed over essentially the entire format during a cut of the positioned open side edge. A transport device transports a respective printed product from the first trimming station to the second trimming station, and from the second trimming station to the third trimming station.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
         [0001]    This application claims the priority of European Patent Application No. 00810705.4-2302 filed Aug. 7, 2000, the disclosure of which is incorporated herein by reference.  
         BACKGROUND OF INVENTION  
         [0002]    The invention relates to an apparatus for automatically trimming the open side edges of bound printed products, such as books or brochures. Such an apparatus includes a trimming station which has a trimming device with at least one blade that cam be driven in a plane extending perpendicular to the extension of the printed products. A positioning device is provided with which a respective side edge of the printed products can be positioned for a cut on a trimming table. A pressing device presses the positioned printed products over essentially the entire format for the cut.  
           [0003]    An apparatus of this type is commercially available under the name “Merit S” by Müller-Martini A G. The apparatus is a so-called three-side trimmer that has a blade for the front cut, the blade being disposed in a trimming station and oriented transversely to the transport direction, and two blades for making the top and bottom cuts which are spaced from one another and oriented in the transport direction. Conveyor belts transport the untrimmed printed products to the trimming station, where they are precisely aligned. A pressing plunger presses the positioned printed products. The pressing pressure is pneumatically adjusted. Trimming is effected against plastic trimming tabs.  
           [0004]    For assuring a high quality, even in books having a thickness of, for example, 4 cm, in the “Merit S” the pressing plunger presses the printed products essentially over the entire format. The pressing plunger is therefore format-specific. If a format changes, a new pressing plunger must be mounted. This device is therefore only suitable for mass production. For producing short uns or individual products with continuously-changing formats, the pressing plungers would have to be exchanged for each format change, and the trimming mechanisms would have to be adjusted to the format. It is therefore not economical to produce short runs or individual products with this dice.  
           [0005]    EP 0 842 746 A discloses a device for trimming the open side edges of bound printed products, in which two respective printed products to be processed are positioned on a rotatable clamping device. The open side edges are trimmed consecutively with one blade; the printed products are rotated after a cut. In this case, the printed products are only pressed in a comparatively small region. Also in this device, if the entire format is supposed to be pressed, the pressing plunger must be exchanged when the format changes.  
         SUMMARY OF THE INVENTION  
         [0006]    It is an object of the invention to produce a device of the aforementioned type that assures a high trimming quality in the trimming of books and brochures, and is also suitable for short runs and individual products.  
           [0007]    The above and other objects are accomplished in accordance with the invention by the provision of an apparatus for automatically trimming the open side edges of bound printed products as first described above, wherein two further trimming stations and a transport device are provided for transporting a respective printed product from the first trimming station to the second trimming station, and from the second trimming station to the third trimming station, and each of the three open side edges of the printed products is trimmed with a stationary blade in each timing station.  
           [0008]    According to a further aspect of the invention there is provided a method for implementing the apparatus of the invention.  
           [0009]    In the apparatus and method of the invention, the three-sided trimming of a book occurs not in a single trimming station, but sequentially in a plurality of consecutive, staggered trimming stations. The pressing device of each trimming station, and particularly the pressing plunger, can be tailored to a maximum format. In printed products having a smaller format, the pressing plunger can harmlessly protrude beyond the printed product at the sides that are not to be trimmed in the respective timing station. Thus, all printed products having the maximum format or a smaller format can be pressed and trimmed without necessitating the exchange of the pressing plungers. It is thus not necessary to exchange the pressing plunger when the format is changed. Because each ng station only requires a single blade, these massive blades can always maintain a fixed position. No complicated adjustment procedure is needed,  
           [0010]    It is possible to process an arbitrary sequence of book sizes consecutively, economically and with a high output, when, in accordance with a modification of the invention, adjustable stops are provided in the individual trimming stations for positioning and aligning the printed products to be trimmed. This adjustment can be made from cycle to cycle, so an arbitrary sequence of book sizes can be processed consecutively and simply. In accordance with a modification of the invention, spring-loaded pressing plungers accommodate a change in the book thickness. If the book thickness changes, therefore, the pressing plungers need not be adjusted to the thickness of the printed products.  
           [0011]    A further advantage of the device according to the invention is that the order of the cuts can be arbitrarily selected and therefore customized for the printed products. The top, bottom and front cuts can therefore be made in a random order. The trimming stations can be arranged consecutively in a line. Other arrangements are also possible, however. In particular, the trimming stations can be arranged such that, for example, printed products having the smallest format or printed products having the largest format can be guided through the trimming stations in a straight line. The corresponding printed products, for example those having the smallest formats may then be subjected to only minimal lateral adjustments in the individual stations. The arrangement of the individual stations can therefore be tailored to the user&#39;s needs. The trimming stations can be offset from one another, for example, or arranged such that the printed products are guided through the trimming stations at an angle with respect to the spine. One of the corners of the printed products is then respectively aligned at stops.  
           [0012]    Further advantageous features ensue from the invention as described in detail below when considered in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 shows a schematic, perspective view of an apparatus in accordance with the invention.  
         [0014]    [0014]FIG. 2 shows a plan view of the apparatus in accordance with FIG. 1.  
         [0015]    [0015]FIG. 3 shows a side view of the apparatus in accordance with FIG. 1.  
         [0016]    [0016]FIG. 4 shows a plan view of a variation of the novel apparatus.  
         [0017]    [0017]FIG. 5 shows a plan view of a further variation of the novel apparatus.  
         [0018]    [0018]FIG. 6 shows a schematic, perspective view of a further variation of an apparatus in accordance with the invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    The apparatus shown in FIGS. 1 through 3 has three trimming stations A, B and C, which are disposed in a line, one behind the other, on a horizontally-oriented trimming table  6 . Each trimming station has a blade  1 ,  2  and  3 , respectively, which is driven vertically in a known manner to make a cut. Each blade has a lower trimming edge  4  that cooperates with a trimming tab  5  secured to the trimming table  6 , or with a lower blade.  
         [0020]    Each station A, B and C is provided with a pressing plunger  13 ,  14  and  15 , respectively, which can move vertically, with means not shown here, for the pressing action. The pressure exerted downward for the pressing action is preferably cushioned with springs, not shown here. A person of skill in the art is familiar with the drive for pressing plungers.  
         [0021]    The apparatus has a transport device  7 , which comprises an endless transport belt  12  that travels around a drive roller  10  and a diverting roller  11  and, as can be seen, is essentially as wide as the pressing plungers  13 ,  14  and  15 . The upper run of the transport belt  12  travels above the trimming table  6  and below the pressing plungers  13 ,  14  and  15 . A fixed tab  43  that constitutes a part of the trimming table  6 , but is located outside of the region of the transport device  7 , is disposed between the diverting roller  11  and the blade  1 . The transport direction of the transport device  7  is indicated by the arrows  32  and  37  in FIG. 1. It therefore travels from the top right to the lower left in FIG. 1.  
         [0022]    Each trimming station A, B and C has a stop element  16 ,  17  and  18 , respectively. On their underside, these elements have a plurality of spaced pins  19 , which end just above tie upper run of the transport belt  12 . The stop elements  16 ,  17  and  18  can be individually and infinitely-variably adjusted in the transport direction of the transport device  7 , as well as in the opposite direction, with drive elements not shown here. In the station A, the pins  19  extend through a respective slot  20  of the pressing plunger  13 . The stop element  16  can therefore be adjusted in the region of the pressing plunger  13 . The stop elements  17  and  18  are located in front of the pressing plunger  14  and  15 , respectively, seen in the transport direction.  
         [0023]    The trimming stations B and C also have a slide  21  and  22  or  23  and  24 , as can be seen particularly clearly in FIG. 2. These slides  21  through  24  can be individually displaced with drive elements, not shown here, in the directions of the two-headed arrows  33  through  36 . The slides  21  through  24  are disposed between the pressing plunger  14  or  15  and the upper run of tie transport belt  12 . They each have a slide rod and a positioning part that extends transversely to the rod. In the example of the slide  23  in FIG. 2, the slide rod is represented by  23   a  and the positioning part is represented by  23   b . FIG. 3 clearly shows how the slides  21  through  24  are respectively disposed between the upper run  12   a  and the pressing plunger  14  or  15 . The slides  21  through  24  could also be replaced by other positioning means, particularly transport belts.  
         [0024]    In the trimming process, a transport device, not shown here, such as a transport belt conveys a printed product  31  to the first trimming station A in the direction of the arrow  32  in FIG. 1. The blade  1  is raised from the trimming tab  5 . The printed product  31  is supplied to the station A such that its bound spine rests against the stop element  16 , and thus against pins  19 , and is aligned by them. In the aligned position, at least a region of the product is located on the transport device  7 . Of course, the pressing plunger  13  is also raised when the printed product  31  is positioned and aligned at the stop element  16 . When the printed product  31  has been positioned and aligned, it is pressed with the pressing plunger  13 ; the stroke of the blade  1  then makes a front cut. The stop elements  16  determine the position of the front cut. For a different format, the stop elements  16  are displaced correspondingly in the directions of the two-headed arrow  44 .  
         [0025]    After the front cut has been made, the pressing plunger  13  is raised, and the transport device  7  transports the printed product  31  to the second trimming station B, where the product is held against the stop element  17 . The slides  21  and  22  displace the printed product  31 ′ transversely to the transport direction of the transport device  7 , and position and align it for the bottom cut. The pressing plunger  14  and the blade  2  are raised here. When the printed product  31 ′ has been positioned and aligned, it is pressed with the pressing plunger  14 , and a stroke of the blade  2  makes the bottom cut.  
         [0026]    When the product  31 ′ has been processed in the timing station B 3 , the pressing plunger  14  is raised and the transport device  7  transports the printed product  31 ′ to the third and final trimming station C. Here, the printed product  31 ′ is held against the stop element  18 . The slides  23  and  24  position and align the printed product  31 ′ for the top cut. The top cut is made through pressing with the pressing plunger  15  and a stroke of the blade  13 . The printed product  31 ″ is now trimmed on the three open side edges, and, after the pressing plunger  15  has been raised, the transport device  7  transports it in the direction of the arrow  37  to a further transport device or another processing station.  
         [0027]    Three printed products  31  can be trimmed simultaneously in the device, The trimming stations A, B and C can therefore process a printed product  31 ,  31 ′ and  31 ″ simultaneously and within a cycle, The output is comparable to that of the known devices of this type. The printed products  31 ,  31 ′ and  31 ″ can have different formats. For example, the printed product  31 ″ could have essentially the format of the pressing plunger  15 . In this case, it would only be necessary to adjust the slides  23  and  24  to the format of the printed product  31 ″. The stroke of the blade  3  and the function and arrangement of the pressing plunger  15  need not be altered.  
         [0028]    The embodiment in accordance with FIG. 4 basically differs from that of FIGS. 1 through 3 in the arrangement of the trimming stations A′, B′ and C′, and the embodiment of a transport belt  12 ′. Relative to the trimming station A′, the trimming stations B′ and C′ are laterally offset in the transport direction of the transport belt  12 ′. A trimming table  6 ′ having a corresponding embodiment is provided. The purpose of this offset arrangement of the trimming stations B′ and C′ is to allow a printed product  31 ″ having a very small format to be trimmed with only very short aligning and positioning movements. The transport path of the printed product  31 ′″ is therefore basically linear. As can be seen, the transport device  7 ′ is comparatively narrow, aid only occupies a partial region of the trimming table  6 ′. The blades  1 ′,  2 ′ and  3 ′ are likewise preferably stationary. The displacement of the stop elements  16 ′,  17 ′ and  18 ′ and the adjustment of the slides  21 ′,  22 ′,  23 ′ and  24 ′ effect the alignment and positioning of the printed product  31 ′″.  
         [0029]    In the embodiment in accordance with FIG. 5, the Riming stations A″, B″ and C″ are disposed such that printed products  31 ,  31 ′ and  31 ″ are guided through the trimming stations A″, B″ and C″ at an angle relative to a spine  45 . The slides  25  through  30  orient the printed products  31 ,  31 ′ and  31 ″ at a corner  46 ,  46 ′ and  46 ″, respectively. A transport device  7 ″ comprises two spaced transport belts  12 ″. A transport belt  8  transports the printed products  31  to this apparatus in the direction of the arrow  38 , and thus, as can be seen, also at an angle to the transport direction  42  of the transport device  7 ″. A transport belt  9  effects the discharge in the direction of the arrow  41 . Two-headed arrows, such as  39  and  40 , indicate the correspondingly inclined displacement of the slides. The advantage of this embodiment is that the stations A″, B″ and C″ only require two respective slides  25  and  26 ,  27  and  28  or  29  and  30 . No additional stop elements are required. The positioning device is therefore especially simple in this embodiment,  
         [0030]    In the embodiment in accordance with FIG. 6, a trimming table  6 ″ is likewise provided as the trimming support surface; here, the table is oriented horizontally, but can also be inclined relative to the horizontal. A first trimming station A′″ is provided with a blade  1 ′″, a pressing plunger  47  and, for transport and positioning, a unit  51  of a transport dice  50 . These slides position an untrimmed printed product (not shown) for the top cut when the pressing plunger  47  and the blade  1 ′″ are raised. The pressing plunger  47  and the blade  1 ′″ are lowered to make the cut. Two cranks  48 , only indicated here, are provided for the stroke of the blade  1 ′″. A sport device, not shown here, transports the printed products in the direction of the arrow  49 .  
         [0031]    After the top cut has been made, the transport device  50 , which comprises two units  51  and  52 , each having a lower belt  53  and an upper belt  54 , transports the printed product to a second to g station B′″, where the front cut is made with a blade  2 ′″ after the product has been positioned. The unit  52  can be used for positioning in the one direction; it clamps the printed product between the upper belt  54  and the lower belt  53 , and is preferably driven independently of the unit  51 . The upper belts  54  of the two units  51  and  52  can be respectively lifted. A pressing plunger  55  effects the pressing.  
         [0032]    The bottom cut is made in a third trimming station C′″, which has a blade  3 ′″ that is moved vertically with cranks  48 . The trimming station C′″ cooperates with the pressing plunger  55  of the trimming station B′″, and the unit  52  can be used for positioning for the bottom cut. After the bottom cut has been made, the printed product  57  is ejected with a transport device, not shown, in the direction of the arrow  56 . The printed product  57  is thus provided with a top cut  58 , a front cut  59  and a bottom cut  60 . The binding  61  is not used for positioning in this embodiment.  
         [0033]    The invention has been described m detail w 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.