Abstract:
An apparatus is provided for pressing a casing or a slip-fold against an adhesive-covered back and adjacent side flanks of a book block, which is conveyed while clamped into a circulating clamp of a perfect binder with the book back projecting downward. The apparatus includes a back pressing device for pressing the casing against the adhesive-covered back and a flank pressing device for pressing the casing against the side flanks. These devices are driven synchronized with the timing of the book binder clamps for conveying the book blocks. At least the flank pressing device is assigned an individual drive unit which is connected to a control device of the perfect binder.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority of European Patent Application No. 07405223.4-1251, filed on Jul. 30, 2007, which is incorporated herein by reference in its entirety. 
       BACKGROUND OF THE INVENTION 
       [0002]    The invention relates to an apparatus for pressing a book casing or a slip-fold against an adhesive-covered back and the adjacent side flanks of a book block, which is transported while clamped into a circulating clamp of a perfect binder with the back projecting downward. Such an apparatus includes a device for respectively pressing the casing against the adhesive-covered back, and a device for pressing the casing against the side flanks, wherein these devices are driven with the synchronous timing of the clamps for transporting the book blocks. 
         [0003]    In a perfect binder, a casing or slip-fold is attached with the aid of adhesive to the back of a book block, composed of loosely gathered sheets. In the process, the back of the book block is first treated to ensure a good connection with the adhesive, the adhesive is then applied to the treated back and/or the casing or a slip-fold and the two parts are joined and pressed against each other. Perfect binders are provided with a plurality of clamps that are attached uniformly spaced apart to a traction device and circulate along an endless path. The book blocks are clamped into these clamps during the complete binding process, such that the backs of the book blocks project downward from the clamps and the side areas adjacent to the back, called the flanks, are freely accessible. Once the unbound book blocks have been transferred to these clamps, they are conveyed past the processing stations arranged along the circular path and are treated at these stations while they are conveyed past. 
         [0004]    The shape and the strength of the book back are important quality features for the binding of a book and are determined in particular also by the function of pressing on the casing or the slip-fold. Known apparatuses for pressing a casing or slip-fold against the back of a book block include a flat back pressing device for pressing the casing against the book back, as well as a flank pressing device, for pressing the casing in the side area adjacent to the book back against the book block by using pressure bars. The shape of the back can be influenced by the chronological sequences between pressing the casing against the back and against the flanks. For example, the backs of books generally have a tendency to be rounded if the flank pressing device reaches the end position on the inside before the back pressing device reaches the upper final position. On the other hand, if the back pressing device reaches its upper end position before the flank pressing device reaches its inner end position, the book backs have a tendency to be angular. The stroke of the flank pressing device must therefore be adjusted to the product against which it is pressed. A larger stroke is generally required for processing the casings than for processing the slip-folds, which can be adjusted by replacing control cams or through a manual adjustment of the drive coupling system. 
         [0005]    German patent document DE 102 27 950 A1 discloses an apparatus for pressing on a casing, which is provided with a control cam, a pivoting lever, and a cam roller for jointly controlling the operation of the flank pressure bars. By moving the lever to different positions, the stroke of the flank pressure bars can be adjusted. This solution has the disadvantage that the adjustments can mutually influence each other and that furthermore the phase position of the flank-pressing device, relative to the back pressing device, cannot be changed. 
         [0006]    It is also known to operate the flank pressure bars directly with the aid of assigned control cams or crank gears, wherein at least the inside end position of a flank pressure bar is embodied to be adjustable for being adapting to the book thickness. The respective control cams or cranks must be replaced for changing the stroke of the flank pressure bar. A high time expenditure is required for replacing parts, which is a disadvantage of this solution. 
         [0007]    During the pressing operation, there should be no or only an insignificant relative speed between the pressing operation and the book block in the longitudinal direction of the book back. 
         [0008]    On the whole, the apparatus is operated either with the aid of a mechanical connection to the drive for the perfect binder, or with the aid of an individual electric drive, which follows the drive for the perfect binder. 
         [0009]    Known solutions using only a single drive for the complete apparatus for pressing on a book casing or slip-fold have the disadvantage that the excess load safety for the single drive lacks response sensitivity because the drive must be adjusted such that it can securely transmit the maximum operating forces without responding. As a result, a response to an excess load of elements with a smaller force requirement is not possible. Known apparatuses furthermore have the disadvantage that mechanical drive elements such as cranks or control cams depend on the division between the clamps. 
       SUMMARY OF THE INVENTION 
       [0010]    It is an object of the present invention to provide an apparatus for pressing on a casing or slip-fold, which can be adjusted and/or adapted with low expenditure during the operation to the requirements of the products to be produced. 
         [0011]    The above and other objects are achieved according to one embodiment of the invention wherein in an apparatus for pressing a book casing or a slip-fold against an adhesive-covered back and the adjacent side flanks of a book block, as first described above, an individual drive unit is assigned to at least the flank pressing device, and such drive unit is connected to a control unit for the perfect binder. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    These and other features and advantages of the invention will be further understood from the following detailed description with reference to the accompanying drawings. 
           [0013]      FIG. 1  shows a detail of a side view of a perfect binder with an apparatus for pressing on a casing or slip-fold. 
           [0014]      FIG. 2  is a view of a section along the plane I-I in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    The apparatus  1  shown in  FIGS. 1 and 2  is attached exclusively to a machine frame of a perfect binder. The backs  12  and the adjacent side flanks  13  of the book blocks  5 , against which the casings or slip-folds are pressed, are clamped into clamps  14  of the perfect binder with the backs  12  projecting downward, wherein the clamps circulate in a transporting direction T. In processing stations located upstream of the perfect binder (not shown herein), the backs  12  of the book blocks  5  are first treated to provide an optimum surface for applying the adhesive. With the aid of a joining device  10 , arranged directly in front of the apparatus  1 , the casings  11  that are supplied by a casing feeder are joined to the book blocks  5  in the region of the back  12  and are pressed against the latter. In  FIG. 1 , this joining device  10  is represented as a roller driven with the speed of the clamps  14 . However, it is also conceivable to use for the joining operation a bar that is driven with the speed of the clamps  14  and lifts the casings  11  up to the backs  12  of the books blocks  5 . In place of the casings  11 , slip-folds  29  can alternatively also be attached at a slip-fold station to the adhesive-covered backs  12 . The adhesive needed for joining the casings  11  or the slip-folds  29  to the book blocks  5  is applied with the aid of roller application systems or nozzle application systems, prior to joining the book blocks  5  and the casings  11  and/or slip-folds  29 . The apparatus  1  essentially consists of a flank pressing device  15 , provided with a front pressure bar  8  and a rear pressure bar  9 , as well as the back pressing device  18 , comprising the individual drive units  23 ,  24  with drive control cams  25 ,  26 , which are assigned to a motorized drive  20 . The drive  20  comprises a motor  3 , which drives the back pressing device  18  approximately at the same speed and in the same conveying direction T as the book blocks, as well as an additional motor  4  that presses the back pressing device  18  against the back  12  of the book block  5 . A carriage  6 , which can move inside a horizontal longitudinal guide  7 , arranged vertically displaceable on the basic frame for the perfect binder, functions as a guiding device for the apparatus  1 . A changeable movement path  27  with an approximately elliptical shape for the carriage  6  with the back pressing device  18  and the flank pressing device  15 , which is necessary for the function of the apparatus  1 , is generated by super imposing a horizontal movement and a vertical movement of the longitudinal guide  7  and/or the carriage  6 . When passing through the center section of the upper portion of the movement path  27 , the casing  11  or the slip-fold  29  are pressed against the back  12  with the aid of the back pressing device  18  and against the side flanks  13  with the aid of the flank pressing device  15 . During the pressing operation, the speed of the back pressing device  18  and the flank pressing device  15  in the transporting direction T must match precisely the speed of the clamps  14  and/or the book blocks  5 . The apparatus  1  is therefore driven with the synchronous timing of the clamps  14  of the perfect binder which transport the book blocks. 
         [0016]    The slip-folds  29  are pressed on in the same way as the casings  11 . However, owing to the fact that the slip-fold legs  29  are only a few millimeters long, the flank pressing device  15  must be operated with a smaller stroke than is required for pressing on the casings  11 . 
         [0017]    The inside end positions for the rear pressure bar  9  and the front pressure bar  8  can be adjusted to the position of the flanks  13  and/or the thickness or thickness differences for the book blocks  5  to be processed. The strokes for the rear pressure bar  9  and the front pressure bar  8  can also be adjusted and essentially depend on whether casings  11  or slip-folds  29  are pressed against the book blocks  5 . The upper end position of the longitudinal guide  7  and/or the back pressing device  18  and the flank pressing device  15  can also be adjusted corresponding to the level of the back  12 . 
         [0018]    The front pressure bar  8 , the rear pressure bar  9 , the longitudinal guide  7  and the carriage  6  are provided with separate drives  16 ,  23 ,  24  and can be driven back and forth in the direction of the double arrows. The illustrated individual drive units  16 ,  23 ,  24  are electric linear drives. However, drive systems with rotary motors and cranks, rack and pinion gear systems, pinion toothed belt drive systems, or spindle nut systems may also be used. The energy can alternatively be supplied either hydraulically or pneumatically. Each individual drive unit  16 ,  23 ,  24  comprises a motor  2 ,  3 ,  4  and a drive control  19 ,  25 ,  26  which supplies the motor  2 ,  3 ,  4  with energy. Sensors, that are not shown herein, are connected to the drive controls  19 ,  25 ,  26  to continuously measure the position of the individual drive units  16 ,  23 ,  24 . The energy supply to the associated motors  2 ,  3 ,  4  is controlled by drive controls  19 ,  25 ,  26 , based on a comparison between the desired positions for the individual drive units  16 ,  23 ,  24  and the actual positions. Systems of this type are known to one skilled in the art under the term “servo drive.” The desired positions for the individual drive units  16 ,  23 ,  24  depend on the actual position of the drive for the perfect binder and the movement principle associated with the individual drive units  16 ,  23 ,  24 . The drive controls  19 ,  25 ,  26  for the individual drive units  16 ,  23 ,  24  are therefore connected to a control device  17  of the perfect binder, to which a position sensor  28  is assigned for detecting the position of the drive for the perfect binder. Owing to the fact that each drive axis is assigned an individual drive unit  16 ,  23 ,  24 , drive parameters can be changed at any time without manual interventions, even during the production. A further advantage is the fact that each individual drive unit  16 ,  23 ,  24  can be adjusted optimally to the driving force required for driving the associated element, thus protecting each individual drive unit  16 ,  23 ,  24  against an excess load. The control device  17  is furthermore provided with an input unit  21 , for example a keyboard, for the input of product data and production data and with an output unit  22 , for example a monitor, for the output of error messages and other data. According to an alternative embodiment, the input unit  21  and the output unit  22  may take the form of a so-called “touch screen system.” 
         [0019]    It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and that the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.