Abstract:
A setting device for bending layer material is provided, which includes a substantially stationary base frame, a running path defining a running direction and a cross-sectional running plane, and first and second guide faces for guiding the layer material. The first guide face includes a bending face on a bending body and the second guide face includes a deflection face. The first and second guide faces are operationally directly interconnected by the layer material when passing between the first and second guide faces. The bending body includes a bending flank directly connecting to the bending face. The bending flank and the deflection face commonly bound a gap traversed by the layer material and defining a gap width, the bending flank defining a gap plane at the gap from the deflection face up to the bending face. The layer material defines a free length which is not in contact with the deflection and bending faces. Positioning means are included for varying the gap width. The positioning means displace the deflection face relative to the bending face to a bending position in which the free length of the layer material is equal to or less than the deflection radius. Oscillations of the layer material in the free length are prevented, thus preventing tearing of the material.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    The present application is a continuation-in-part application of U.S. patent application Ser. No. 09/049,731 filed Mar. 27, 1998. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The invention relates to a device with which flexible or elastic materials can be worked to achieve a desired non-stressed shape, such as a flat shape. Such materials may be substrates or other rollable materials having a constant thickness which are worked as individual sheets or as an endless material web.  
           [0004]    2. Description of the Background Art  
           [0005]    Paper is frequently supplied as a reeled material web, and therefore tends to curl, i.e. a portion of the web when spread out flat is subject to an inherent bending stress and thus tends to curve or curl to relieve the bending stresses on release of external forces. However, it may also be desirable to bend or work a flat layer which is planar when free of stress in order that it will assume a curved position. In any case, bending of the material breaks the stresses in the material by moving a face of the material which is to be curved relative to a bending face. In this arrangement the material defines an angle of wrap in the portion which comes into contact with the bending face. This angle of wrap is determined by the position of a deflector or guide for the material provided next to the bending face. This deflector may be provided upstream and/or downstream of the bending face. For modifying the angle of wrap or for optionally working both faces of the material the deflector arrangement and the bending face means are preferably adjustable relative to each other. For this purpose the bending face may be positioned on a device frame so that it can be adjusted relative to the deflector during the entire bending operation, e.g. to transpose material sections in sequence having continuously changing curl tendencies into the same, non-stressed planar shape or the like. Such an adjustment may, however, result in a bulky configuration involving complicated control mechanisms and control movement inertia which makes it difficult to quickly react to varying curl tendencies or other properties of the material. If the length of the material section that is tensioned freely or linearly between the bending face and the deflection face is greater than the deflection radius of the deflection face, in addition to the aforementioned drawbacks, the material section oscillates at high running speeds to the detriment of consistent good quality working.  
           [0006]    U.S. Pat. No. 3,661,703 to Shelor discloses a decurling apparatus for controlling the curl characteristics of a web. The web is drawn over one of a pair of decurling rollers, the position of which may be varied to change the sharpness of the angular path of the web. The free web length between the decurling roller and an adjacent turn roller is at least approximately twice the radius of the turn roller, and can be substantially more, depending on the position of the decurling rollers. The systems of Shelor would be subject to oscillations of the web, yet Shelor does not include any suggestion as to how to avoid or reduce such oscillations.  
           [0007]    Transverse oscillations are generated when the paper or material is unsupported and conveyed at low or high speed but exposed to air currents and machine oscillations. These oscillations of the paper result in oscillations of the surrounding air. The oscillations of the paper and the air tend to rhythmically superimpose, increasing the amplitude of oscillation of the paper or even sympathetic vibration. Such oscillations lead to alternating tensile stresses and consequently exceed the fatigue yield of the paper, causing tearing of the paper. These oscillations tend to become higher as the deflection radius becomes smaller.  
         OBJECTS OF THE INVENTION  
         [0008]    An object is to overcome the drawbacks of known configurations of the kind described. A wide variety of stresses should be introduceable into the material by simple constructional means.  
         SUMMARY OF THE INVENTION  
         [0009]    According to a first aspect of the present invention, a setting device for bending layer material is provided, which defines remote first and second layer faces and a layer thickness. The setting device includes a substantially stationary base frame, a running path defining a running direction and a cross-sectional running plane, and first and second guide faces for guiding the layer material. The first guide face includes a bending face on a bending body and the second guide face includes a deflection face. The deflection face defines a deflection axis and a deflection radius. The bending face defines a bending axis and a bending radius smaller than the deflection radius. The first and second guide faces are operationally directly interconnected by the layer material when passing between the first and second guide faces. The bending body includes a bending flank directly connecting to the bending face. The bending flank and the deflection face commonly bound a gap traversed by the layer material and defining a gap width, the bending flank defining a gap plane at the gap from the deflection face up to the bending face. The layer material defines a free length which is not in contact with the deflection and bending faces. Positioning means are included for varying the gap width. The positioning means displace the deflection face relative to the bending face to a bending position in which the free length of the layer material is equal to or less than the deflection radius.  
           [0010]    The deflection face and the bending face thus define boundaries to a relatively narrow gap which permits material to pass preferably free of compression stress. The clear width of the gap (and hence the free length of the layer material) is variable so that the minimum gap width is many times smaller than the deflection radius when the material wraps around the bending face. This width can be measured in an axial plane of deflection passing through the center of the bending face or the angle of wrap. The minimum width for a particular device may be smaller than half, a quarter or a tenth of the deflection radius, or smaller than 50 or 30 times the thickness of the material so that the free running zone between the two guiding faces is at most as large as the deflection radius, and is preferably smaller as compared thereto corresponding to one of the cited values.  
           [0011]    Although the position of the bending face may be adjusted during the bending operation it is, however, advantageous to have only the deflection face adjustable transverse to the deflection axis since the distances involved and time required for such positioning are relatively small. Positioning means is preferably provided so that the deflection face can be set tangentially to the plane of the bending flank.  
           [0012]    A web of paper to be worked is expediently secured with its leading edge overlapping a trailing edge of an advanced paper web, e.g. by an adhesive tape before the ends or the seam reaches the working station. If the seam is passed on an arc or angle of wrap through the working engagement at the bending face it may easily tear. For this reason, the guiding faces may be mutually displaceable in sudden short impulses so that the seam can be guided past one or both guiding faces without curvature or even contact, thus preventing damage.  
           [0013]    Although the device can be made for bending engagement with only one face of the material, it is expediently configured for alternating bending engagement on both faces. For this purpose two separate bending faces are mutually and separately adjustable relative to the device frame. The deflecting faces provided for this purpose, on the one hand, and the bending faces, on the other hand, face each other and are minimally spaced from each other by a spacing which is maximally as large as the deflection radius or smaller. The deflecting faces may be formed by rotational faces or rollers, the clear width therebetween as measured in their common axial plane being smaller than their radius. At both deflecting faces and at the bending face the material may be simultaneously guided and thus curved alternately in opposite directions.  
           [0014]    In accordance with a further aspect of the invention a setting device for bending layer material to vary curl characteristics of the layer material is provided. The setting device has remote first and second layer faces, and includes a stationary base frame and a running path defining a running direction and a cross-sectional running plane. Guide faces, namely first and second guide faces for separately guiding the layer material are provided. The first guide face includes a bending face for varying the curl characteristics and the second guide face includes a deflection face having first and second subfaces. The bending face is spaced from the first and second subfaces in the running direction. The first subface defines a first deflection axis and the second subface defines a second deflection axis. The bending face defines a bending axis and a bending radius, with at least one of the first and second subfaces defining a deflection radius larger than the bending radius. The bending face also defines running sides, namely a feed side at which the layer material runs toward the bending face and an exit side at which the layer material runs off the bending face. The first and second subfaces are located at only one of the running sides. Positioning means are included for operationally directly interconnecting one of the first and second subfaces and the bending face by the layer material when passing between the deflection face and the bending face. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    Example embodiments of the invention are explained in more detail in the following and illustrated in the drawings in which:  
         [0016]    [0016]FIG. 1 is a side view of a device for a multi-ply material web;  
         [0017]    [0017]FIG. 2 is a partially sectioned view as seen from the right of a single subdevice of the arrangement as shown in FIG. 1;  
         [0018]    [0018]FIG. 3 is a section through the bending tools as shown in FIG. 2;  
         [0019]    [0019]FIG. 4 is a view of a bending body as shown in FIGS. 2 and 3;  
         [0020]    [0020]FIG. 5 is a longitudinal section through the bending body as shown in FIG. 4;  
         [0021]    [0021]FIG. 6 is a scrap view of the bending body as shown in cross-section in FIG. 3 on an enlarged scale;  
         [0022]    [0022]FIG. 7 is a scrap view of the suction connection of the bending body;  
         [0023]    [0023]FIG. 8 is a cross-sectional view of the mounting arrangement of one end of the bending body;  
         [0024]    [0024]FIG. 9 is a cross-sectional view of the bearing means of the other end of the bending body; and  
         [0025]    [0025]FIG. 10 is a scrap view of a further embodiment of the subdevice as shown in FIG. 1. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    As shown in FIG. 1 a plurality of equal bending devices  1  are arranged in a station  2  horizontally juxtaposed and spaced from each other by an amount which is smaller than the space requirement for a single device  1 . Each bending device is designed to work a separate material web  3  in a working zone. In these working zones the materials  3  have parallel running directions  4  that are inclined downwardly in running planes  5  which are parallel to each other. Each device  1  is arranged as a module for facilitated removal from a frame  6 . A multi-layer material web  7  in which the webs  3  are located initially congruently on each other is fed horizontally and above the devices  1  to station  2  from separate reel stands, firstly in an aligned configuration at a roller  9  and then downstream thereof the individual material webs  3  are each deflected in sequence from the web  7  at a plurality of upper deflection rollers  8  and fed directly to the associated device  1 . From the working zone each material web  3  is fed to devices  11  located below the working zone. At the devices  11 , the materials  3  are placed one on another in sequence to again form the multi-ply web  7 .  
         [0027]    In front of and behind the devices  1  the frame  6  comprises portals  12  and  13  respectively, each composed of rods, the vertical supports of these portals being connected to each other via horizontal girders  14  located on both sides of the material  3 . The device modules  1  are mounted on top of girders  14  and can be removed together therewith as a unit from the remaining frame  12 ,  13 . The upper ends of portals  12 ,  13  are likewise interconnected with girders on which the deflectors or rollers  8  are rotatably mounted in sequence.  
         [0028]    The single-layer material  3  is fed as an endless web to the working zone of each individual device  1  via a cylindrical guiding and deflection face  15  over which the material  3  is wrapped at a maximum angle of 90°. From face  15  the material is stretched and passes directly to a guiding or bending face  16  formed by a corner edge that is rounded in cross-section. The guiding face  15  is formed by a rotating roller or deflector body  17  and the bending face  16  by a rounded edge of a stationary bending body  18  comprising rectangular flat cross-sections throughout. Deflector body  17  and bending body  18  cover the full width of the material. Any dirt or dust appearing in the working zone or in the vicinity of a gap  20  is continuously removed by fluid flow, for example by suction means  19 . A plane  10  of gap  20  slants downwards in the running direction  4  and coincides with the flank of the bending face  16  which directly opposes guiding face  15  and is formed by an entirely planar larger face  21  of bending body  18 . The running plane  5  is steeper than plane  10  (face  21 ) so that the material  3  passes through the gap  20  from one gap boundary formed by face  15  to the opposite gap boundary formed by face  16  at an acute slanting angle before then being deflected on bending face  16  downwardly and away from face  15  over an angle of less than 90°. The free length of material  3  between the two boundaries  15 ,  16  is extremely short, but continuously variable. This length is at most the same as, and is preferably smaller than the radius of deflector body or roller  17  and is preferably half or a quarter thereof.  
         [0029]    Guiding face  15  is curved about a horizontal deflector axis  22 , oriented parallel to running plane  5  and at right angles to direction  4 . Bending face  16  is curved about a bending axis  24  orientable parallel thereto. The two convex curved faces  15 ,  16  greatly differ in their radii of curvature, the radius of face  15  being at least 10 to 20 times or up to about 30 times larger than the radius of face  16 . Face  15  is adjustable about a positioning axis  25  oriented parallel to axis  22 , the positioning axis  25  being fixed on frame  6  and located on the side of axis  22  or of deflector body  17  that faces away from gap  20  or plane  10 .  
         [0030]    The two ends of deflector body  17  are secured or rotationally mounted on two supports  26 ,  27  each of which is rotationally mounted about axis  25  over at least 120° or 360° with bearings  28  and  29  respectively located at the corresponding outer sides of supports  26 ,  27 . Unit  17 ,  26 ,  27  can be radially removed from frame  6 , where necessary, together with bearings  28 ,  29 . For precise, continuous adjustment about axis  25  positioning means  30  are provided which comprise an upright rotational motor  31  and a gear such as an angular gear  32  directly flanged thereto. Gear  32  is secured to the upper side of one member  14  and is self-locking. The corresponding support  26  is secured directly to the freely protruding output journal of gear  32  so that the gear bearing of gear  32  directly forms the corresponding sole bearing  28  for positioning unit  17 ,  26 ,  27 , eliminating the need for any further separate or frame-fixed bearing on this side. The positioning means  30 ,  40 ,  42 ,  43  or the suction means  19  may be arranged optionally on both sides of gap  20  by e.g. arranging gear  32  optionally on each one of members  14  and the connection  52 ,  53 ,  54 ,  55  optionally in the region of each one of members  14 . Due to this arrangement, the operator side of the device  1  may be located optionally on either side of the device  1  and, where necessary, separate from suction means  19 , and positioning means  30 ,  42 .  
         [0031]    For adjusting the unit  17 ,  26 ,  27  control means  33  are provided on the outer side of gear  32  facing away from the unit. Control means  33  comprise a control cam  34  located in axis  25  of the output journal of gear  32  and arranged directly on an other journal positioned on the same gear shaft. The periphery of cam  34  acts on a sensor  35 , such as an inductive transducer, so that by setting a variable signal value the positioning means  30  may be stopped when the corresponding position of deflector body  17  is attained. An analog indication of the position is provided by an optical display  36  on the outer side of the bearing  29 .  
         [0032]    The flat bending body  18  has a constant, full-length, outer cross-section and is replaceably secured to a rod or supporting body  37 . Supporting body  37  is larger in cross-section than bending body  18 . Supporting body  37  is cross-sectionally configured as a flat rectangular tubular body carrying body  18  intimately adjoined therewith on one of its two wider outer faces. Due to this the side faces of body  18  adjoining edges  16  are located in the planes of the two narrower outer faces of body  37 , as can best be seen in FIGS. 3 and 6. The ends of unit  18 ,  37 , more particularly only the ends of body  37  are rigidly connected with circular disk-shaped flanges  38  which are replaceably fixed to plate-shaped supporting flanges  38 ′ of frame  2  by axial bolts which can be screwed into place from the interior of device  1  towards the outside thereof. Once the axial bolts have been released, unit  18 ,  37  can be radially removed from supporting flanges  38 ′ or conversely reinstalled.  
         [0033]    Face  16  is manually adjustable, using positioning means  39  or  40 , relative to unit  17 ,  26 ,  27  and frame  6  separately about two positioning axes  45 ,  46  located at right angles to each other, namely using the positioning means  40  during operation and using the positioning means  39  when operation is stopped. Axis  46  is oriented parallel to bending face  16  and to axes  22 ,  25  and is located to the side of bending face  16  facing away from gap  20 ,  10  roughly in the center axis of supporting body  37  or of the associated flanges  38 . For passage of the said axial bolts flanges  38  comprise slots curved about axis  46  so that the inclination of the bending face  16  and gap flank  21  can be steadily varied and then locked in place by clamping action of the axial bolts. In one position of unit  15 ,  26 ,  27 , the flank  21  is located at right angles to the common axial plane  47  of axes  22 ,  25 , axial plane  47  intersecting flank  21  directly adjacent to bending face  16 . From this position planes  10 ,  47  can be steadily displaced in both opposing directions. Plane  47  also spacedly opposes bending face  16  and thus slants relative to plane  10 . In a center position the clear width of gap  20  is at a minimum, increasing steadily when varied in both directions as is evident from the positions indicated by dot-dashed lines in FIG. 3. The minimum gap width is preferably more than one millimeter and less than three or five millimeters. Positioning movements of both positioning means  30 ,  39  result in such changes in the gap width, positioning means  39  establishing the smallest possible gap width.  
         [0034]    Positioning means  40  permit mutually slanting adjustment of bending face  16  and axes  24 ,  46 , on the one hand, and of guiding face  15  and axes  22 ,  25  on the other. The cited gap width settings remain constant over the positioning length of positioning means  40 . Positioning means  40  set a first end, remote from positioning means  30 , of unit  18 ,  37  about positioning axis  25  whilst the other end of this unit merely pivots about frame-fixed axis  45 , i.e. including the corresponding supporting flange  38 ′ in each case. Axis  45  is always located in the same axial plane as axis  25  and is laterally juxtaposed with the axial planes of axes  22 ,  24 ,  46  oriented parallel thereto. It is possible to translate axis  22  to also be in this common axial plane using the positioning means  30 . The supporting flange  38 ′ for the flange  38  located at the first end of unit  18 ,  37  is adjustable by a guide  41  curved about axis  25 , this guide comprising a guide pin engaging a curved slot with zero diametral clearance and rigidly connected to supporting flange  38 ′. The mounting about axis  45 , which is oriented transverse or inclined to flank  21  or plane  10 , is formed by a joint  42  comprising a joining pin fixed to frame  6  in the location of axis  45 .  
         [0035]    Each of the bearings defined by guide  41  and joint  42  comprises a mounting body  48  fixed to frame  6  laterally on the inside of the corresponding member  14 . A first mounting body  48  carries guide  41  and the other mounting body carries, in a bifurcated arrangement, the joining pin of joint  42  which passes through the corresponding supporting flange  38 ′ between the forked arms of the corresponding mounting body  48 . After this adjustment the unit  18 ,  37  needs to be locked only in the region of guide  41  by suitable means  43 , for example by clamping. For this purpose a manually lever-operable clamping device is provided with which guide  41  can be axially tensioned relative to its corresponding mounting body  48 . To facilitate manual adjustment along the guide  41  the corresponding supporting flange  38 ′ is provided with a radially protruding handle  44  adjoining the inner side of this mounting body  48 . Clamp  43  is accessible directly on the underside of the corresponding member  14 .  
         [0036]    Bending body  18  as shown in FIGS.  4  to  6  consists of an integral metal body, the surface of which is completely coated, or at least coated in the region of the four longitudinal edges or bending faces  16 , e.g. with a vacuum-deposited film of a harder substance, such as a ceramic oxide film or the like, having a thickness which is at most about a tenth or half a tenth of a millimeter, for example. Body  18  is optionally turnable about its longitudinal center axis and about its transverse axis oriented at right angles thereto so that with respect to member  37  each of its four edges or bending faces  16  can be optionally brought into the same working position for engaging the material  3 . For this purpose fastening means for reversible bending body  18  comprise countersinks  49  on both flat sides of reversible bending body  18 . The countersinks  49  are for fastener bolts with which bending tool  18  can be tensioned optionally with both flat sides against the corresponding flat side of member  37 . Edges  16  may have different radii of curvature so that one bending body  18  may have different working edges or bending faces  16  for adapting to various working requirements.  
         [0037]    Suction means  19  are stationary or not exposed to positional changes in operation, and comprise a slot-shaped fluid or suction orifice  50  located in surface  21  and passing transversely through body  18  centrally between edges  16 . Opening  50  is oriented parallel to edges  16  and in line between countersinks  49 . The corresponding wall of member  37  is provided with a coincidental fluid opening connecting the port of opening  50  to a flow passage  51 . Passage  51  is bounded solely by the inner sides of member  37 , runs full length over the latter and has at one or both ends constricted connectors  52  which are provided for both gaps  20  at the remote outer sides of support flanges  38 ′ and laterally adjacent to guide  41  or axis  45 . A flexible tube  53 , e.g. a hose, is connected to connectors  52  and traverses the underside of the corresponding member  14 . The other end of tube  53  is connected via a slanting connection  55  to a longitudinal passage  54 . Secured to the other longitudinal section of each member  14  is one such longitudinal passage  54  having a rectangular or square cross-section, into the side wall of which the connection  55  issues at an acute angle inclined to the flow direction in passage  54  to eliminate flow losses. The end of passage  54  located nearer to the frame part of deflector  9  translates via a bend into a passage  56  which is oriented vertically upwards, the upper end of passage  56  being connected to a suitable pressure/suction source, such as a blower.  
         [0038]    As shown in FIGS. 1 and 2, only one single simultaneously effective tool edge or bending face  16  is provided for each working zone or device  1  so that tool engagement is possible on one face only of the corresponding material  3 . The configuration as shown in FIG. 3 is suitable for providing tool engagement optionally on both faces of the material  3 . For this purpose identical units  18 ,  37  are secured to the same support flanges  38 ′ on both sides of axial plane or axis  45  and are adjustable about axis  46  independently of each other as well as being removable independently of each other. The working faces or bending edges  16  of these two units spacedly oppose each other symmetrically to plane  45 . Flanks  21  are counter inclined so that their planes  10  are oriented at an obtuse angle in a V-formation to each other. Supports  26 ,  27  likewise support two separate deflecting faces  15 ,  15 ′ on identical deflection bodies  17  having separate deflection axes  22 ,  23  arranged symmetrically on both sides of an axial plane of positioning axis  25 . In one position this axial plane coincides with plane  45  so that the material  3  is able to pass from deflector  8  to deflector  11  without contact between rolls  17  and bending bodies  18 , i.e. without being deflected in the working zone. By pivoting unit  17 ,  26 ,  27  into the position as shown in FIG. 3 the material  3  is transferred from a deflection at a first material face on one guiding face  15  into bending engagement of the other material face with one of the bending edges or faces, namely the right-hand face  16 . By pivoting in the opposite direction the material  3  is correspondingly brought into engagement with the other bending face  16  (the left-hand face  16 ) by the other deflection face  15 ′.  
         [0039]    Due to pivoting about axis  25  the angle of wrap at the corresponding edge or bending face  16  can be varied dynamically and continuously during operation. Thereby the wrap angle at the corresponding deflection face  15 ,  15 ′ as well as the width of gap  20  may also be changed. Gear  32  automatically locks each setting by the inner obstruction of its gear members. Independently of this, the wrap angle and gap width can be altered by positioning means  39 . In this respect also the two flanges  38  could be displaced relative to each other in torsional deformation of unit  18 ,  37  to achieve differing wrap angles along the length of edge or bending face  16 , as is possible by positioning means  40 . However, the dynamic variation is undertaken not with bending bodies or tools  18  but with deflector bodies  17  resulting in a very simple configuration of the suction means  19 . Each passage  51  is connected to one of the connectors  52 . All devices  1  are connected on each side to a common longitudinal header passage  54 . The ends of the two passages  54  are connected to a common riser passage  56  via a Y-connector. Since the deflectors  17  cannot come into contact with bending bodies or tools  18  or other components of the device  1  even when fully rotated about axis  25 , no means for restricting travel such as limit switches are needed. Each bending body or tool  18  or the edge or bending face  16  thereof may also be replaced by a rotating rod, the bearings of which may be flanged to the support flanges  38 ′ or provided on flanges  38 . All components are located so as to be freely accessible, thus greatly facilitating maintenance or insertion of the material  3 .  
         [0040]    As shown in FIG. 3, on the side of the deflector  17  facing away from bending body  18 , namely between deflectors  8 ,  17  or  11 ,  17  a further material guide  57  may be provided located nearer to deflector  17 . Guide  57  does not deflect during bending but when the material  3  is guided past without contacting bending face  16  or at the most only slightly touching it. For each deflection face  15 ,  15 ′ material guide  57  comprises a corresponding frame-fixed deflector  58 ,  58 ′ or cylindrical rod or the like. In one position, deflection face  15  forms a tight passage gap with deflector  58  for S-shaped reversing deflection of the material  3  and in the other position for likewise oppositely deflecting in the region of an equal deflector gap between deflection face  15 ′ and deflector  58 ′. The material passes through the deflection gap in each case without any clamping pressure so that only one material face has deflector contact at any moment. Deflectors  58 ,  58 ′ are secured to flanges  59  and thus adjustable and removable at a support flange  59 ′ as already described with respect to flanges  38 . Accordingly, here too, positioning means may be provided corresponding to means  39 ,  40 , the deflectors  58 ,  58 ′ like the deflectors  16  each being located eccentrically to the corresponding positioning axis.  
         [0041]    In the embodiment shown in FIG. 10 the deflectors  17  are provided spacedly downstream of bending faces  16  and deflector  8  is located upstream of faces  16  as shown in FIG. 1. To engage and disengage the passage control mode for a non-worked passage of material  3  past the faces  16 , the drive  31  is powered by a fluid cylinder. Drive cylinder  31  comprises two separate cylinders, each separately controllable and rigidly connected to each other in series. The piston rods face away from each other. Each cylinder can be transposed separately into two end positions so that four stop-limited working strokes, namely that of each individual cylinder and the two working cylinders are achieved. Instead of the deflectors  17  being fixedly mounted to the frame, the units  18 ,  37  or the supporting flange  38 ′ are pivoted about axis  25  of deflector  8  by drive  31 . Thereby each of the two tools or bending bodies  18  can optionally be brought into engagement with the material  3 . Fine adjustment of the tool  18  or of its wrap angle is achieved manually via gearing such as a worm gear.