Abstract:
The present invention relates to a copy-carrying cylinder which has a peripheral surface ( 2 ) supporting sheet-like copies and which is provided with retaining elements for fixing the sheet-like copies in place on the peripheral surface ( 2 ). A folding device ( 5 ) which can be moved into and out of openings ( 4 ) at the peripheral surface ( 2 ) are bounded by at least one movable surface element ( 13 ). The surface element ( 13, 13.3 ) which is associated with the folding device ( 5 ) is designed in such a manner that it takes its closed position ( 22 ) automatically.

Description:
[0001]    Priority to German Patent Application No. 101 02 808.3, which is incorporated-by-reference herein, is hereby claimed.  
         BACKGROUND INFORMATION  
         [0002]    The present invention relates to an automatically closing surface element at the periphery of cylinders, for example, at the periphery of copy-carrying folding cylinders in folding apparatuses.  
           [0003]    U.S. Pat. No. 5,429,578 relates to a folding apparatus for a rotary printing press. In a folding apparatus for cutting and folding continuous material webs from which folded copies are cut off are included a cutting cylinder and a transfer cylinder cooperating therewith. The transfer cylinder is driven and, moreover, cooperates with a folding jaw cylinder. The transfer cylinder includes an outer surface at which a number of sets of impaling pins and folding blades are accommodated which push the copies that are cut off from the continuous material web into folding jaws. The transfer cylinder is designed in such a manner that the rotational position between the sets of impaling pins and the folding blades can be varied. In the region of the outer surface of the transfer cylinder, moreover, a set of closing surfaces are accommodated on each side of a folding blade and of a set of impaling pins, the closing surfaces moving relative to each other in such a manner that they overlap one another, thus forming a virtually continuously closed outer lateral cylinder surface, independently of the rotational position of the sets of impaling pins and of the folding blades on the copy-carrying cylinder with respect to each other.  
           [0004]    U.S. Pat. No. 6,071,224 discloses a copy-carrying cylinder having guides for extensible folding elements. The copy-carrying cylinder provided in a copy-processing machine includes two opposing and cooperating cylinders receiving copies on their peripheral surfaces. The copies which are retained on the peripheral surface of one of the cylinders are conveyed by an extensible folding device into receiving elements at the peripheral surface of the other cylinder. At the peripheral surface of one of the cylinders, provision is made for covers bounding an opening through which a folding device, which is accommodated in a hollow space in the interior of the cylinder, moves in and out.  
           [0005]    The design approaches known from the related art indeed limit the opening at the peripheral surface of a copy-carrying cylinder in the region of a folding device which move in and out but can be accessed only with considerable effort from the lateral surface of the folding cylinders which are difficult to access anyway, for example, for replacing a worn out folding device such as sets of impaling pins or folding blades.  
         SUMMARY OF THE INVENTION  
         [0006]    In view of the indicated related art, an object of the present invention is, on one hand, to maintain an as continuous as possible peripheral surface on copy-carrying cylinders and, on the other hand, to provide an easy way to access folding devices which are supported in the interior of the cylinder.  
           [0007]    The present invention provides a copy-carrying cylinder having a peripheral surface ( 2 ) for carrying sheet-like copies which can be acted upon by a folding device ( 5 ) which is used for producing a fold and which can be moved out of an opening ( 4 ) in the cylinder ( 1 ). A movable surface element ( 13 ) is associated with opening ( 4 ), wherein the surface element ( 13 ,  13 . 3 ) is designed and arranged near the folding device ( 5 ) in such a manner that, via the application of a pressure force, it can be moved into an open position in which it enables access to the folding device ( 5 ), and that it automatically moves from the open position into a closed position subsequent to canceling the pressure force.  
           [0008]    The advantages which can be attained using the design approach according to the present invention are to be seen above all in that it allows the clearance next to a retractable and extensible folding device at the peripheral surface of copy-carrying cylinders to be closed so that a virtually continuous lateral cylinder surface ensues. Corners are prevented from being turned down during the transfer of the sheet-like copies from the peripheral surface of a copy-carrying cylinder to the peripheral surface of another copy-carrying cylinder cooperating therewith. Besides, the arrangement of a pivoted surface element proposed according to the present invention offers the possibility of easy access to the fastening elements for a folding device in a hollow space provided underneath the lateral surface of a copy-carrying cylinder. The closing of the pivoted surface element is assisted by the centrifugal force acting upon the hinged surface element during the operation of the copy-carrying cylinder. The surface element can be swiveled open in an easy and simple manner using a tool, for example, a wrench so that there is immediate access to fastening elements for a folding device such as impaling pin bearing arrangements or folding blades or the like.  
           [0009]    In an advantageous embodiment of the basic idea of the present invention, the surface element can have a one-part or also a multipart design. If the hinged surface element is designed in one piece, it acts as a guide surface for tools to be introduced into the hollow space underneath the peripheral surface of the copy-carrying cylinder; if the surface element has a multipart design, a hinged segment of the surface element can be adapted in optimum manner to the tool to be introduced into the hollow space underneath the peripheral surface.  
           [0010]    The surface element can be advantageously accommodated on a wall bounding the opening in the peripheral surface of the cylinder. The cylinder can be provided, for example, with a hinge bearing which supports the surface element more or less centrically and which allows the hinged surface element to deflect from a closed position (operation) into an open position (maintenance work).  
           [0011]    At the hinge bearing, the surface element can be moved about a swivel pin which can have a spring element associated therewith.  
           [0012]    In a first variant of an embodiment, the spring element can be designed as a spiral spring which surrounds the swivel pin and whose free legs, on one side, are braced against the lower side of the surface element which is deflectable about the swivel pin and, on the other side, are braced against a wall which bounds the hollow space underneath the lateral cylinder surface. Besides, it is possible for the spring element to be designed as a pressure spring which can be articulated both to the hinge bearing of the surface element and to the lower side of the surface element.  
           [0013]    In the one-part embodiment of the hinged surface element, the hinged surface element can be provided with a contact surface over the opening for the retractable and extensible folding device, the contact surface plunging into a recess provided at the peripheral surface of the copy-carrying cylinder, when in the closed position. In this variant of an embodiment, the surface element, when in its closed position (operation), forms a virtually continuous surface with the adjacent region of the lateral cylinder surface.  
           [0014]    In another variant of an embodiment of the surface element proposed according to the present invention, it is possible for the surface element to have a multipart design, i.e., provision is made for a hinged segment and a stationary segment of a surface element. The hinged segment of the surface element can be put against the wall of the hollow space underneath the lateral cylinder surface in a spring-loaded manner by introducing a tool, while the stationary segment remains in its position. According to this variant of an embodiment, the size of the hinged segment of the surface element can advantageously be adapted to the maximum size of a tool to be introduced into the hollow space underneath the lateral cylinder surface.  
           [0015]    Using the design approach proposed according to the present invention, the accessibility of fastening elements in hollow spaces of cylinders as, for example, copy-carrying cylinders in folding apparatuses or rotary printing presses is considerably simplified. A removal of the cylinders for maintenance work can be avoided, permitting a drastic reduction of down times of folding apparatuses and rotary printing presses cooperating therewith for carrying out maintenance work. Via the action of centrifugal force during the rotation of the cylinders, it is ensured that the pivoted surface elements or segments of the surface elements always take their closed position while the copy-carrying cylinders are in operation, resulting in a virtually continuous peripheral surface of the copy-carrying cylinders designed according to the present invention during the operation thereof. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    In the following, the present invention will be explained in detail with reference to the drawings, in which:  
         [0017]    [0017]FIG. 1 shows a surface element which is associated with a retractable and extensible folding device and takes its closed position automatically;  
         [0018]    [0018]FIG. 2 depicts the surface element according to the representation in FIG. 1 in its open position with a tool introduced into the interior of a copy-carrying cylinder; and  
         [0019]    [0019]FIG. 3 represents an alternative variant of an embodiment of a surface element which is divided into two parts. 
     
    
     DETAILED DESCRIPTION  
       [0020]    A surface element which automatically takes its closed position and is associated with an extensible folding device such as a folding blade is shown in FIG. 1.  
         [0021]    A cylinder  1 , for example, a copy-carrying cylinder in a folding apparatus (folding blade cylinder) is provided with an opening  4  in which is accommodated a retractable and extendible folding device  5 . On a lateral cylinder surface  2  of cylinder  1  are carried copies to be folded which are cut off from a continuous material web and which are pushed by retractable and extensible folding device  5  into folding jaws of a folding jaw cylinder (not shown here) cooperating with cylinder  1  according to the representation in FIG. 1.  
         [0022]    Folding device  5  schematically shown in FIG. 1 as defined herein can both folding blades and impaling pins or the like, which are cyclically retracted into lateral cylinder surface  2  and cyclically extended out therefrom again for pushing copies into open folding jaws. To carry the copies on lateral cylinder surface  2  in a careful manner, the lateral cylinder surface can be provided with an elastic surface coating  3 .  
         [0023]    Cyclically retractable and extensible folding device  5  can be supported on a swivel axle  7 , a spacer  8  being provided between swivel axle  7  and a receptacle  9 . Between spacer  8  and receptacle  9  for a folding device  5 , the folding device is clamped with its lower region via a clamping screw  10 . To slacken or tighten screw  10 , which is necessary for replacing folding device  5 , screw head  11  of clamping screw  10  must be accessible. Swivel axle  7 , spacer  8 , receptacle  9  for folding device  5  are accommodated in an interior space  28  underneath a cover  6  covering swivel axle  7  and underneath a pivoted surface element.  
         [0024]    According to the representation in FIG. 1, surface element  13  is formed in one piece. It supports itself on a hinge bearing  14 ,  16  which is fastened via a screw connection  15  to the side wall of an inner wall bounding interior space  28  inside of cylinder  1 . Surface element  13  is accommodated off-center on hinge bearing  14  and is able to swivel about a swivel pin  16  provided on hinge bearing  14 . Moreover, swivel pin  16  accommodates a spring element  17  which is preferably designed as a spiral spring. The free legs of the spiral spring are braced against lower side  13 . 2  of surface element  13  on one side and, on the other side, against a wall of interior space  28  at bearing  14 . The upper side of surface element  13 , which is depicted in its closed position  22 , is denoted by reference numeral  13 . 1 . In this position, a contact area  18  lying beyond opening  4  for the retractable and extensible folding device  5  plunges into a recess  19  provided in the wall which bounds interior space  28 . In closed position  22 , the end of surface element  13  facing retractable and extensible folding device  5  has a distance  21  from the tip of folding device  5  which is shown here in the retracted position. Closed position  22  represented in FIG. 1 corresponds to the operating position of surface element  13  which, on one hand, is forced into its closed position  22  by the spring force applied via spiral spring  17 , the spring force being assisted during operation by centrifugal forces  20  developing during the rotation of the copy-carrying cylinder. The limit position of surface element  13  in its closed position  22  is constituted by the contact of contact area  18  with the upper side of recess  19 .  
         [0025]    Discernible in FIG. 2 is the surface element according to FIG. 1 in its open position with the tool plunging into the interior of the copy-carrying cylinder.  
         [0026]    During a standstill of copy-carrying cylinder  1  and for carrying out maintenance work such as the replacement of folding device  5  accommodated on receptacle  9 , a tool  25 , for example a wrench, is introduced into interior space  28  of cylinder  1 . To this end, tool  25  is introduced into interior space  28  along upper side  13 . 1  of pivoted surface element  13 . In its open position  23 , surface element  13  takes the position shown in FIG. 2, upper side  13 . 1  of pivoted surface element  13  serving as a guide slope for tool  25  to be introduced. According to FIG. 2 when surface element  13  is in open position  23 , the legs of spiral spring  17  are pressed together, biasing surface element  13 . A free leg of spiral spring  17  is braced against lower side  13 . 2  of surface element  13  while the other leg of spiral spring  17  lies against hinge bearing  14 ,  16 . In open position  23 , contact area  18  facing away from opening  4  has moved out of recess  19  which constitutes the limit stop for closed position  22  shown in FIG. 1 of one-piece surface element  13  supported on hinge bearing  14 ,  16 . Introduced tool  25  can now be engaged onto screw head  11  of clamping screw  10  and moved in a direction perpendicular to the to the drawing plane. Surface elements  13  can be flat surfaces extending over the width of a copy-carrying cylinder in opening region  4 ; however, surface elements  13  can also be positioned in the region of each clamping screw  10  for fastening a folding device  5  in such a manner that they are arranged side by side at a distance from each other over the width of copy-carrying cylinder  1 .  
         [0027]    [0027]FIG. 3 represents an alternative variant of an embodiment of a surface element which is divided into two parts.  
         [0028]    It can be seen in FIG. 3 that a surface element  13  can include both a stationary part  13 . 4  inserted in recess  19  in the region of lateral cylinder surface  2  and a segment  13 . 3  which can swivel about a swivel pin  14 . When tool  25 , which is shown here in dashed representation, is introduced into interior space  28  of cylinder  1 , pivoted segment  13 . 3  of a multipart surface element  13  swings out of the way into interior space  28  against the action of a spring element  26 . Upper side  13 . 1  of hinged segment  13 . 3  of the surface element acts as a guide slope for introducing tool  25  and for engaging it onto screw head  11  of clamping screw  10 . While hinged segment  13 . 3  of surface element  13  swings down into interior space  28  of cylinder  1 , spring element  26  is compressed. Spring element  26  can be designed as a tension-compression spring which can be articulated to the cylinder on one side and which can be articulated with its opposite end to the lower side of hinged segment  13 . 3  of surface element  13  at articulation points  27 . Subsequent to tightening clamping screw  10  and removing tool  25  from interior space  28  of the cylinder, hinged segment  13 . 3  of multipart surface element  13  swings from its open position  23  into its closed position  22 .  
         [0029]    This movement is assisted by the tension release of spring element  26  which is articulated to the lower side of hinged segment  13 . 3  and to the cylinder  1  at articulation points  27 . When multipart surface element  13 . 3 ,  13 . 4  is in its closed position  22 , the distance identified by reference numeral  21  ensues between the leading edge of hinged segment  13 . 3  and the tip of folding device  5  retracted into interior space  28 . In the preferred embodiment of the present invention, swivel pin  14  of surface element  13  is preferably arranged in such a manner that centrifugal forces  20  resulting from the rotation of the cylinder will not cause the leading edge of the hinged segment to be deflected out of the periphery of cylinder  1 . In other words, swivel pin  14  of surface element  13  is arranged offset from the center of mass of surface element  13  at a distance in such a manner that surface element  13 . 3  is automatically moved into the closed position and retained therein by the centrifugal forces during a rotation of cylinder  1 . This results in the advantage that only a comparatively small spring force needs to be applied by spring element  17  to always ensure a reliable closure of surface element  13 , which is designed as a shutter, at all rotational speeds of printing-machine cylinder  1  but, on the other hand, that surface element  13  can be opened by applying a very small pressure force onto the region of surface element  13  near the folding blade, for example, with the tip of an adjustment tool or wrench.  
         [0030]    Spring element  26  is dimensioned such that developing centrifugal forces  20  will not cause the leading edge of hinged segment  13 . 3  to deflect beyond the position shown in FIG. 3 with respect to the retracted tip of folding device  5 .  
         [0031]    Using the design approach according to the present invention, on one hand, it is possible to attain a quick access to fastening elements  10  for folding device  5 , whether they are folding blades or sets of impaling pins, in interior spaces  28  of copy-carrying cylinders or on other cylinders of folding apparatuses or of rotary printing presses. Besides, it is guaranteed that during the operation of the cylinders designed according to the present invention, the closure of the access openings which are only required for maintenance work is ensured, on one hand, by preloading elements and by centrifugal forces  20  which develop during operation and act upon hinged surface elements  13  formed in one piece and upon hinged segments  13 . 3  of multipart surface elements. Because of this, a virtually continuous lateral cylinder surface  2  is formed during the operation a of copy-carrying cylinder  1  designed according to the present invention so that clearances in the region surrounding retractable and extensible folding device  5  on copy-carrying cylinders can be effectively closed. Turning down of comers or other impairments of page areas or whip effects occurring during the transfer of folded copies from lateral cylinder surface  2  into open folding jaws on folding jaw cylinders are thus reduced or even obviated.  
         [0032]    “Copy” as defined herein includes all printed products, and includes printed products produced by a printing press and includes signatures.  
                                             List of Reference Numerals                                     1   Cylinder            2   Lateral cylinder surface            3   Surface coating            4   Opening            5   Folding device            6   Cover            7   Swivel axle            8   Spacer            9   Folding device receptacle           10   Clamping screw           11   Screw head           12   Guide           13   Surface element           13.1   Upper side           13.2   Lower side           13.3   Hinged segment           13.4   Stationary segment           14   Bearing           15   Fastening screw           16   Swivel pin           17   Spring element           18   Contact area           19   Recess           20   Centrifugal force           21   Distance           22   Closed position           23   Open position           24   Guide surface           25   Tool           26   Tension-compression spring           27   Articulation point           28   Interior of cylinder