Abstract:
A cylinder, which is part of a folder, includes a cylinder body with at least one gripper that can be moved between a retracted position within the cylinder body, an extended position, and a clamping position in which a tip of the gripper presses flat material against a surface section of the cylinder body. A pivot axis, about which the gripper pivots between its retracted position and its extended position, is within the cylinder body. A counterthrust element, which cooperates with a separate cutting blade, to cut the flat material which is to be gripped by the gripper, is associated with the cylinder body. The gripper is situated upstream of the counterthrust element, in the rotational direction of the gripper cylinder. A second axis, about which the gripper moves in the peripheral direction of the cylinder, is also provided. Both of these axes are fixed in relation to the cylinder.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This patent application is the U.S. National Phase, under 35 USC 371, of PCT/EP2004/052282, filed Sep. 23, 2004; published as WO 2005/032989 A1 on Apr. 14, 2005, and claiming priority to DE 103 44 950.7, filed Sep. 27, 2003, the disclosures of which are expressly incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention is directed to a cylinder of a folding apparatus, having a cylinder body and at least one gripper. The at least one gripper is movable between a non-use position, lowered into the cylinder body, an extended position and a clamping position.  
       BACKGROUND OF THE INVENTION  
       [0003]     A gripper cylinder, which has one or several grippers on its shell face, which grippers are movable between a position in which they keep a leading edge of a piece of flat material, which is to be conveyed on the gripper cylinder, pressed against the shell face, and a release position, in which the flat material can be released again, or a fresh piece of flat material can be picked up and clamped, is generally known. The grippers typically perform a pivot movement between these two positions. Since the periods of time available for accomplishing such clamping or releasing of a product are short, the pivot movement must be performed at a high speed. The movement amplitude between the clamping position and the release position of the gripper should be as small as possible in order to keep strong accelerations, which stress the material, within limits.  
         [0004]     To prevent damage to a trailing end of a piece of flat material, which trailing end is maintained on the cylinder by a gripper, and which possible damage may be caused by the movement of a gripper which, in the course of clamping a following piece of flat material, which piece of flat material follows in the circumferential direction of the cylinder, most gripper cylinders are laid out for picking up pieces of flat material which are fed to the gripper cylinder spaced apart from each other. The spaced apart pieces of flat material respectively each come to rest against the gripper cylinder while forming a gap between successive pieces. The gripper can thus move in the gap, without touching the respectively previous piece. If these pieces of flat material were previously produced by being cut off a continuous web, in order to form such a gap, the cut-off pieces must be accelerated to a speed which is greater than that of the continuous web, prior to its being cut. However, if a conveying system, which conveys the products cut off the continuous web further after such cutting, runs faster than the fed-in continuous web, this results in slippage. Such slippage results in friction between the conveying system and a leading section of the continuous web penetrating it which continuous web, prior to its being cut off, necessarily still moves at the original speed of the continuous web of which it is a part. In connection with flat material which have a sensitive surface, such as, for example freshly printed products, this friction can impair the quality of the surface, for example by the imposition of drag marks or of smudging of the ink. Moreover, if the pieces of flat material are put together from a stack of sheets, which sheets are not connected with each other, the problem arises that different friction between different sides of the stack can lead to the sheets being displaced with respect to each other, and the stack being pulled apart. Such displacement makes the further processing of the stack considerably more difficult.  
         [0005]     It is particularly problematical if the pieces of flat material are cut off from the continuous web when these pieces are in direct contact with the gripper cylinder, such as, for example, by the use of a rotating cutter cylinder which, together with the gripper cylinder, defines a cutting gap, and which rotating cutting cylinder severs the continuous web while working together with a counterthrust element of the gripper cylinder. To insure that the continuous web to be cut is placed evenly against the surface of the gripper cylinder, the gripper must be capable of being lowered into, or of dipping into the interior of the gripper cylinder. After a piece of flat material has been cut off from the fed-in continuous web, there is only a brief period of time which is available for accomplishing the gripping of a freshly formed leading edge of the continuous web, by the use of a gripper, and the pressing of this freshly formed leading edge against the surface of the cylinder. However, the path between the lowered position of the gripper and the extended position of the gripper, in which extended position the gripper presses the flat material against the cylinder, is long and requires a high speed of the gripper movement, which high speed of movement can only be realized by the use of a high quality expensive drive mechanism. Moreover, increasing wear, and therefore susceptibility to failure, of the drive mechanism becomes higher, the greater the operating speed becomes.  
         [0006]     A gripper cylinder is known from EP 0 931 748 B1 and from DE 198 57 507 A1, which is capable of conveying printed products, that are cut off a fed-in continuous web, without a lead, i.e. without a space between the successive printed products. In this gripper cylinder, a gripper is mounted on a shaft, which shaft is pivotably seated, via a translation mechanism, in the cylinder, and which drives the gripper, that is coupled to the pivot movement, to perform a parallel displacement. This translation mechanism is used to displace the gripper between its lowered position and a position in which the gripper is projecting past the shell face of the cylinder, from which projecting position, the gripper can be pivoted around the shaft in order to press the leading edge of a continuous web of printed products against the cylinder surface.  
         [0007]     DE 100 60 713 A1, U.S. Pat. No. 6,093,139 A and U.S. Pat. No. 953,063 A each describes a folding apparatus with a gripper cylinder having a cutter strip for engagement by a cutter of a cutter cylinder, which is working together with the gripper cylinder. The grippers of the gripper cylinder are pivotable, around a first, movable shaft, for clamping the material to be transported. This first shaft is, in turn, seated on a lever, which lever is pivotable around a second shaft that is fixed in place on the cylinder. This lever is controlled, with the aid of a first cam disk, for providing a movement of the gripper in the cylinder circumferential direction. A second cam disk controls the clamping movement of the gripper.  
         [0008]     DE 102 03 059 A1 discloses a transport cylinder with a gripper for use in transporting sheets of imprinted material. The gripper can be moved by the use of two pivot shafts, which are fixed in place on the cylinder, and by a further pivot shaft, which further pivot shaft is pivotable around one of the pivot shafts that is fixed in place on the cylinder. Only one cam disk is provided for control.  
         [0009]     U.S. Pat. No. 5,429,578 and U.S. Pat. No. 5,004,451 show folding blade cylinders which work together with tapes for accomplishing the guidance of products.  
       SUMMARY OF THE INVENTION  
       [0010]     The object of the present invention is directed to providing a cylinder of a folding apparatus, including a cylinder body and at least one gripper. A two-stage movement of the at least one gripper takes place with little stress of the mechanical components and with a high degree of accuracy.  
         [0011]     In accordance with the present invention, this object is attained by the provision of at least one gripper which can be moved between a position lowered into the interior of a cylinder body, an extended position and a clamping position. A shaft is arranged so that the gripper can make a pivoting movement about it between the lowered and extended positions. A second shaft is used to allow the gripper to move in the circumferential direction of the cylinder. Both of these shafts are fixed to the cylinder. A least one tape, which acts with the cylinder, can be arranged in an area between the cutter cylinder and a folding jaw cylinder.  
         [0012]     In a manner that is generally the same as that performed by the gripper cylinder which is known from EP 0 931 748 B1, the gripper cylinder, in accordance with the present invention, makes use of a translatory movement, in addition to the pivot movement, for shortening the movement path or distance between the retracted position and the clamping position of the gripper. In accordance with the present invention the difference is that a mechanism, for use in driving the translation, is not pivotable, together with the gripper, around the pivot shaft of the latter and in this way increases its moment of inertia. Instead, the mechanism shifts the shaft of the gripper as such, in the radial direction. Since the radial lift, which is required for clamping or for releasing the flat material from the gripper cylinder, is small, in comparison to the required movement amplitude of the gripper in the circumferential direction, a small amplitude of the radial shifting movement is sufficient. This small amplitude of radial shifting movement can be generated with a small outlay of energy and with the imposition of little stress on the mechanical components.  
         [0013]     If the flat material to be clamped by the gripper is a stack of sheets, it is desirable to avoid a movement component of the gripper in the circumferential direction of the cylinder, at the moment of clamping the stack, so that the stack is not subjected to shear forces during such clamping. The clamping is customarily accomplished only by a pivot movement of the gripper. Accordingly, the exertion of a shearing force on a stack of sheets during such clamping cannot be avoided. However, with the gripper cylinder in accordance with the present invention, it is preferably provided that the first shaft is moved radially inward, in a final phase of the pivot movement, into the clamping position.  
         [0014]     A simple and rugged possibility for driving the radial inward movement of the first shaft, into the clamping position, is to mount the first pivot shaft on a first arm, which first arm is pivotable around a second shaft, which second shaft is pivotable, with respect to the cylinder body, so that the radial movement of the first shaft corresponds to a pivot movement of this first arm.  
         [0015]     In a manner which is essentially the same as the customary pivot movement of the gripper itself, this pivot movement of the first arm can be driven, in a simple manner, by a cam disk, which cam disk does not rotate together with the gripper cylinder and whose shape is traced by a lever that is connected with the first arm.  
         [0016]     A coupling rod is provided for driving the pivot movement of the gripper between the lowered position and the clamping position. One end of this coupling rod is hinged on the gripper and the other end is hinged on a second arm, which second arm is pivotable around a third shaft. As discussed above, pivot movement of this coupling rod can also be driven by a cam disk.  
         [0017]     In a space-saving arrangement of the present invention, the second and third shafts are on opposite sides of the gripper, in respect to the circumferential direction of the cylinder.  
         [0018]     Of the two arms, the first is oriented more in the circumferential direction. Of the cylinder body. The second arm is oriented more in the radial direction of the cylinder body. In other words, the orientation of the first arm is closer to the cylinder circumferential direction than is that of the second arm, and the orientation of the second arm is closer to the radial direction than is that of the first arm.  
         [0019]     A counterthrust element is assigned to each gripper on the cylinder body which counterthrust element, working together with a cutter that is moved together with the gripper cylinder, is used for cutting flat material which is fed to the gripper cylinder and which is then to be grasped by the gripper.  
         [0020]     With respect to a direction of rotation of such a gripper cylinder, the gripper is arranged upstream of the counterthrust element which is assigned to it. The surface cross section of the gripper cylinder, against which the gripper presses cut flat material, preferably is the gripper&#39;s counterthrust element itself, and whose elasticity aids in the cutting process, as well as in the gripping process. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     A preferred embodiment of the present invention is represented in the drawings and will be explained in greater detail in what follows.  
         [0022]     Shown are in:  
         [0023]      FIG. 1 , a schematic side elevation representation of a transverse folding apparatus utilizing a gripper cylinder, in  
         [0024]      FIG. 2 , an enlarged, partial sectional view through the gripper cylinder, and which shows a gripper in its lowered position in the gripper cylinder, in  
         [0025]      FIG. 3 , a partial sectional view analogous to that in  FIG. 2 , and which shows gripper in the course of the gripper being moved from its lowered position, in  
         [0026]      FIG. 4 , a partial sectional view showing the gripper in a clamping position, in  
         [0027]      FIG. 5 , a partial sectional view showing the gripper during its return travel to its lowered position, in  
         [0028]      FIG. 6 , a schematic representation corresponding to  FIG. 2 , in  
         [0029]      FIG. 7 , a schematic representation corresponding to  FIG. 4 , in  
         [0030]      FIG. 8 , a schematic representation corresponding to  FIG. 5 , in  
         [0031]      FIG. 9 , a schematic representation corresponding to  FIG. 1 , and in  
         [0032]      FIG. 10 , a schematic view from above on a gripper cylinder in accordance with the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0033]     A greatly simplified, cross-sectional view through a folding apparatus, such as, for example a folding apparatus of a web-fed rotary printing press in accordance with the instant invention, is represented in  FIG. 1 . The folding apparatus includes a cylinder  01 , for example a gripper cylinder  01  which, in the example represented here, is equipped with five grippers  02 , which grippers  02  are evenly distributed in the circumferential direction of cylinder  01 , and with folding blades  03 . A plurality of these grippers  02  are arranged, for example, individually supported in the axial direction of the cylinder  01 . A cutter cylinder  04 , which is depicted here with two cutters  06 , cooperates with the gripper cylinder  01  and constitutes a cutting gap  09 . A flat material  07 , such as, for example, a continuous web  07 , which web  07  is generally composed of a plurality of imprinted webs of material placed on top of each other, such as, for example paper webs, is fed into the cutting gap  09  and is separated into individual flat materials  08 , such as, for example, individual printed products  08 , each individual printed product  08  having a length corresponding to a printed page.  
         [0034]     In the course of their respective passing through the cutting gap  09 , the grippers  02  and the folding blades  03  have each been lowered into the interior of the gripper cylinder  01 . The circumferential speed of the gripper cylinder  01  corresponds exactly to the feeding speed of the continuous web  07 . The printed products  08 , which are cut off the continuous web  07 , follow each other, without gaps, on the circumference of the gripper cylinder  01 . There is thus no relative movement between the lower or inner surface of the web of material and the surface or barrel of the gripper cylinder  01 .  
         [0035]     “Exactly” and “no” should be understood in the technical sense. In other words, negligible tolerances can possibly occur.  
         [0036]     Following their passage through the cutting gap  09 , each of the grippers  02  is respectively moved out of the gripper cylinder  01  below or beneath the trailing section  11  of a previously gripped one of the printed products  08  now carried on the gripper cylinder  01  and is pivoted in a direction of rotation which is opposite to that of the gripper cylinder  01  in order to clamp the newly formed leading edge  12  of the continuous web  07  against the surface of the gripper cylinder  01 . The trailing ends  11  of each printed product  08  are spaced away, at a finite distance, from the surface of the gripper cylinder  01 . However, this trailing end displacement does not hamper the even winding of the continuous web  07  on the gripper cylinder  01 , since these trailing ends  11  are only spaced away from the gripper cylinder  01  after having been cut off from the continuous web  07 .  
         [0037]     The gripper cylinder  01  constitutes a folding gap  13  in cooperation with a folding jaw cylinder  14 . In the course of their passage through the folding gap  13 , the folding blades  03  carried by the gripper cylinder  01  are moved out of the gripper cylinder  01  to thereby insert the printed products  08 , along a transverse center line, into folding jaws, which are not specifically represented, of the folding jaw cylinder  14 . The printed products  08 , which are transversely folded in this way, are further conveyed on the folding jaw cylinder  14  to a location where they are transferred, for example, to a bucket wheel for delivery onto a conveyor belt, both of which are not specifically represented.  
         [0038]     In a partial sectional representation, which is taken transversely in respect to the gripper cylinder  01 ,  FIG. 2  shows a gripper, generally at  02 , and its surroundings. The gripper  02  includes a support beam  16 , which extends over the entire usable width of the gripper cylinder  01 . A double-L or double-Z profiled element  17 , that may be made of an elastic material, such as spring steel, is located on a radially outward directed side of support beam  16 . The profiled element  17  can be extended out from cylinder  01  for clamping the printed products in place on the surface of cylinder  01 . The profiled element  17  can extend continuously in the axial direction of the gripper cylinder  01 . Alternatively, it can be divided into a plurality of tines that are spaced apart in the axial direction, which plurality of tines respectively each extend through an opening in the shell face of the gripper cylinder  01 .  
         [0039]     A lower, first end of the support beam  16  is hinged to a first end of a first arm  19 , which has a second end that is fixedly connected with a first shaft  21 , which first shaft  21  is rotatably supported in the gripper cylinder  01 , but which is stationary in the cylinder. In other words, the first shaft  21  can rotate in the cylinder  01  about its longitudinal axis but can not be displaced or repositioned in the body of cylinder  01 . The first arm  19  extends approximately parallel to the shell face of the gripper cylinder  01 . The lower end of the support beam  16  is furthermore hinged, through a lower extension, and by a first pivot shaft  28 , whose position relative to the gripper cylinder  01  can be changed, to a coupling rod  22 . The coupling rod  22  is also oriented approximately parallel to the shell face of the gripper cylinder  01 . Coupling rod  22  is itself hinged, by a second pivot shaft  29 , whose position relative to the gripper cylinder  01  can also be changed, to an approximately radially oriented second arm  23 . This second arm  23  is fixedly connected with a second shaft  24 , which second shaft  24  is rotatably seated in the gripper cylinder  01 . The various rotated position of the two arms  19 ,  23  is, as represented in  FIGS. 6, 7  and  8 , are determined by two cam disks  31 ,  32 , as seen in  FIGS. 6-8  and  10  and which do not rotate together with the gripper cylinder  01  which cam disks  31 ,  32  are traced by respective rollers  33 ,  34 , which rollers  33 ,  34  are each connected by an arm  36 ,  37  with the shaft  21  or  24 , respectively.  
         [0040]     The rollers  33 ,  34  are preferably resiliently pressed against the cam disks  31 ,  32 , in particular by the use of a torsion spring. The cam disks  31 ,  32  are arranged offset in the axial direction with respect to each other, and with respect to the gripper cylinder  01 .  
         [0041]     It may be seen, by referring to  FIG. 2 , that a rotation of the first arm  19  around the first shaft  21  substantially causes a radial inward or outward movement of the gripper  02 , and also causes, at most to a lesser degree, a pivot movement of the gripper  02  around a third pivot shaft  27  to which both the support beam  16  and the first arm  19  are hinged. A rotation of the second shaft  24  would, with the first shaft  21  assumed to be fixed, result in a pivot movement of the gripper  2  around the third shaft  27 .  
         [0042]     Therefore, a two-stage movement of the gripper  02  is possible by use of the two cam disks  31 ,  32 . The cam disks  31 ,  32  have the effect that the pivot movement and the clamping movements of the gripper  02  can each take place substantially independently of the other.  
         [0043]     The gripper cylinder  01 , as represented in part in  FIG. 2 , rotates in a counterclockwise direction. A hard rubber strip or counterthrust element  26 , which includes a surface section, has been inserted in the cylinder shell and is located, in a clockwise direction of the cylinder shell, behind the opening in the cylinder shell receiving the profiled element  17 . This rubber strip  27  is used, for example, as a counterthrust element  26 , extending in the axial direction, for engagement by the cutter  06  of the cutter cylinder  04  when that cutter  06  is cutting the continuous web  07 . In the movement direction of the cylinder  01 , the gripper  02  is arranged directly in front of, or before, the counterthrust element  26 , which is provided for cutting. A distance “a” between a tip of the gripper  02  in its lowered state, as seen in  FIG. 2 , and of an edge of the counterthrust element  26  is less than 30 mm, and in particular is less than 10 mm. In the configuration represented in  FIG. 2 , in which the gripper  02  has been lowered into the interior of the gripper cylinder  01 , the gripper  02  can pass through the cutting gap  09 , wherein the continuous web  07 , which is not represented in  FIG. 2 , is cut through at the height, or the location of the counterthrust element  26 . To accomplish the grasping of the leading edge  12  of the continuous web  07  which is being formed in the cutting process, and to push it against the counterthrust element  26 , the gripper  02  is moved out of the gripper cylinder  01 .  
         [0044]      FIG. 3  shows an intermediate position in the course of the gripper&#39;s moving-out process. As can clearly be seen, the first shaft  21  has been rotated in a counterclockwise direction between the configuration of  FIGS. 2 and 3 . As a result of this rotation, the third pivot shaft  27  has been displaced radially outward and the profiled element  17  of the gripper  02  has risen through the opening in the cylinder shell. As a result of a slight turning of the second shaft  24  in the clockwise direction, the gripper  02  has furthermore been pivoted around the third pivot shaft  27  in a clockwise direction, so that the tip of the free leg  18  of the profiled element  17  is located radially above the counterthrust element  26 .  
         [0045]     As represented in  FIG. 4 , the third pivot shaft  27  of the gripper  02  is again radially displaced into the interior of the gripper cylinder  01  by a rotation of the first shaft  21  in a clockwise direction, so that the free leg  18  of the profiled element  17  is lowered onto the counterthrust element  26 . This clamps the leading edge of the continuous web  07 , which is not represented in  FIG. 4 , and which is located between free leg  18  and the counterthrust element  26 , between the two.  
         [0046]     Following the passage of the gripper  02  through the folding gap  13 , as seen in  FIG. 1 , the gripper  02  is raised again by a rotation of the first shaft  21  in a counterclockwise direction. The printed product  08 , clamped between the gripper free leg  18  and the counterthrust element  26 , is released, as shown in  FIG. 5 . The first shaft  24  now pivots in a counterclockwise direction in order to pull the gripper  02  over the counterthrust element  26  and over the opening in the cylinder shell. By the imposition of a subsequent rotation of the first shaft  21  in a clockwise position, the gripper  02  is again pulled back into the interior of the gripper cylinder  01  and into the position indicated in  FIG. 2 . The gripper  02  is now ready for a further passage through the cutting gap  09 .  
         [0047]     As can be seen, a narrow pivot angle of the gripper  02  is sufficient to move it between the clamping position and the lowered position. The radial lift of the gripper  02  is also limited, depending on the thickness of the printed products  06  to be processed, to a few millimeters. Since the gripper  02  can be constructed in a simple manner, its weight and moment of inertia are low. The short lifts which are traveled between the lowered position and the clamping position of the gripper  02  require small accelerations and therefore require only reasonable, material-saving driving forces.  
         [0048]      FIG. 9  shows a gripper cylinder  01  with three gripper systems  02 , such as, for example, three grippers  02 . The gripper system  02 , which is located in the area of the cutter cylinder  04 , is in the lowered position, i.e. in the cutting position. The gripper system  02 , which is located in the area between the cutter cylinder  04  and the folding jaw cylinder  14 , is in the closed position, i.e. in the clamping position. The gripper system  02 , which is arranged downstream of the folding jaw cylinder  14 , is in the opened position, i.e. in the release position.  
         [0049]     A tape guide can additionally be arranged between the cutter cylinder  04  and the folding jaw cylinder  14 . These tapes press the cut-off printed products  08 , i.e. the signatures, against the shell face of the gripper cylinder  01 . Several tapes are arranged to be spaced apart in the axial direction, so that the grippers  02  can run without interference in these spaces formed between the several tapes.  
         [0050]     The tape guidance can be driven from either the gripper cylinder  01  or the folding jaw cylinder  14 . The tape guidance can also be driven by frictional connection or by its own separate motor.  
         [0051]      FIG. 10  shows a schematic view from above of a gripper system  02  in accordance with the present invention.  
         [0052]     While a preferred embodiment of a cylinder pertaining to a folder and comprising a cylinder body and at least one gripper, in accordance with the present invention, has been set forth fully and completely hereinabove, it will be apparent to one of skill in the art that various changes in, for example the type of printing press used to print the continuous web, the specific drives for the cylinders and the like could be made without departing from the true spirit and scope of the present invention which is to be limited only by the following claims.