Abstract:
A turning device uses a turning bar for diverting a material web. The turning bar includes a sleeve with a plurality of holes and an inner chamber that is supplied with compressed air, as well as a closing body. The turning bar is supported by a frame and is able to pivot through 90°. The closing body is movable within the inner chamber in response to this pivoting movement of the turning bar. Movement of the closing body closes one of two groups of the holes, depending on the position of the turning bar. The turning bar is connected to the frame at only one end and is supplied with compressed air through a joint connecting the turning bar to the frame.

Description:
FIELD OF THE INVENTION 
     The present invention is directed to a turning device having a turning bar. The turning device is useable for rerouting a web of material. 
     BACKGROUND OF THE INVENTION 
     In order to be able to process webs of material which are fed from two diametrically opposed directions to a single downstream located machine, or in order to be able to feed paper webs, which are coming from the same direction, to two different machines for further processing, turning bar arrangements have been developed. The turning bars are movable between two work positions, each of which causes a rerouting of the web of material by 90°, into opposite directions. 
     Such a turning bar arrangement is known from DE 43 11 438 C2. This turning bar arrangement comprises a plurality of turning bars. Both longitudinal ends of each turning bar are hingedly connected with support spindles of a rack and each turning bar end can be displaced, along these support spindles. The turning bars can each assume two different work positions, in which they each extend at an angle of 45° in relation to the support spindles. The turning bars can each be transferred from one of their work positions into the other of their work positions by a pivot movement of 90° in the plane defined by the axes of the support spindles and of the turning bars. This transfer takes place through movement of the turning bars through an intermediate position, in which each of the turning bars extends perpendicularly with respect to the support spindles. To make such a transfer possible, it is necessary for each of the support spindles to be movable, coordinated with the movement of the turning bars, perpendicularly with respect to each other. 
     Turning bar arrangements are also known, in which the turning bars can be switched from one work position into the other work position on an axis which is parallel to the plane defined by the axes of the support spindles and of the turning bars. However, such a turning bar arrangement requires sufficient space, either above or underneath of this plane, for performing the transfer movement. 
     DE 29 20 684 A1 discloses a linear actuating member for pivoting a turning bar. 
     DE 31 27 872 C2 describes a turning bar, whose first end is seated changeably in a rack, and whose second end is displaceably seated in a guide device. Compressed air is supplied through a link, and the guide devices can be displaced by use of linear drive mechanisms and can be secured by use of clamping devices. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is directed to providing a turning device with a turning bar which can be simply and dependably pivoted. 
     In accordance with the present invention, this object is attained by the provision of a turning device having a turning bar for rerouting a web of material. A rack supports the turning bar for pivotal movement. The turning bar has a free longitudinal end which is not connected directly to the rack and which extends, in a cantilever manner from the rack. An actuator is usable to pivot the turning bar through 90° between the two work positions. At least one fixation device is usable to secure the turning bar in its two work positions. The actuator may be a linear actuator, particularly a pneumatic cylinder. The linear actuator may be connected with the rack and the turning bar. 
     An advantage which can be achieved by the use of the present invention lies, in particular, in that the mechanical structure of the turning device is simplified. A hinged connection of the second longitudinal end of the turning bar with the rack is omitted. Therefore, neither a second support spindle, nor any mechanism for controlling its movements, are necessary. Passage of a compressed air feed line through a link connecting the turning bar with the rack permits a particularly compact construction especially in the vertical direction. Moreover, it is possible to do without a flexible pipe line, which flexible line is in danger of wear or damage, for conducting the compressed air to the turning bar. 
     When the turning bar in accordance with the present invention is employed for rerouting webs of material of varying widths, it is desirable to be able to limit the size of the surface area of the jacket of the turning bar, from which compressed air exits to form an air cushion underneath the web of material to be rerouted, in accordance with the width of the web of material. For this purpose, at least one piston, which axially limits the compressed air-supplied interior of the turning bar, is axially displaceable inside the turning bar. 
     Since a free end of the turning bar is not needed for use in connecting the compressed air feed line to the turning bar, an actuating element for use in adjusting the position of the at least one piston can preferably be conducted out of the turning bar at this free end. This actuating element can have, for example, the shape of a knurled wheel or of a crank for use in turning a threaded bar which is extending through the turning bar, in the longitudinal direction of the turning bar, and whose screw thread meshes with a threaded bore in the piston. 
     A closing body, which is used for the selective closing of each of a group of holes in the jacket of the turning bar, is preferably embodied as a hollow cylinder. The at least one piston can be displaced within this hollow cylinder. This arrangement makes it possible to move the closing body and the at least one piston independently of each other. 
     If the at least one piston is arranged in the turning device at the longitudinal end of the turning bar which is connected with the link, it is necessary to conduct the compressed air, which is fed into the interior of the turning bar, through this piston. For this purpose, a section of the compressed air feed line in the interior of the turning bar, is embodied as a tube section which traverses the piston. 
     The rack which supports the turning bar has two stops for use in fixing the end position of the pivot movement freedom, which two stops are preferably adjustable. 
     Furthermore, at least one fixation device, for use in fixing the turning bar in respective end positions of the pivot movement freedom, is provided. This fixation device preferably comprises a bolt which is connected with the rack for engaging a projection of the turning bar. In accordance with a simple embodiment of the present invention, the bolt is pivotable around an axis extending vertically with respect to a longitudinal axis of the turning bar. 
     The closing body, which is provided for the selective closing of a respective group of holes in the jacket of the turning bar, is preferably rotatable between its two positions around the longitudinal axis of the turning bar. In comparison with the axial displaceability of the closing body disclosed in DE 43 11 438 C2, this feature of the present invention permits an increased stroke length of the movement of the closing body. Demands made on the positional accuracy of the holes in the jacket and in the closing body can accordingly be relatively low. 
     To facilitate a rapid switching of the turning device between the two work positions of the turning bar, it is possible to provide a linear actuating member, in particular a pneumatic cylinder, for accomplishing the pivoting movement of the turning bar. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the present invention are represented in the drawings and will be described in greater detail in what follows. 
       Shown are in: 
         FIG. 1 , a top plan view, partially in section, and showing the base area of a turning bar, which is hingedly connected with a rack in accordance with a first preferred embodiment of the present invention, in 
         FIG. 2 , a cross-section taken along the line A-A in  FIG. 1 , in 
         FIG. 3 , a top plan view of a free end area of the turning bar, in 
         FIG. 4 , a cross-section along the line B-B in  FIG. 1 , in 
         FIG. 5 , a top plan view of a turning bar in accordance with a second preferred embodiment of the present invention, and in 
         FIG. 6 , a top plan view of a fixation device in accordance with a third preferred embodiment of the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In a top plan view, partially in section,  FIG. 1  shows a portion of a rack of a turning arrangement, as well as an end area of a turning bar  01  mounted thereon, in accordance with the present invention, which end area of turning bar  01  is called the base area. The rack comprises two support spindles  21 , which are seated fixedly and parallel in a frame, which is not specifically represented, and a rack threaded spindle  22  which is rotatably seated between the support spindles  21 . A sliding body  23 , for example a sliding pad  23 , is supported by the support spindles  21  and can be displaced in the longitudinal direction of the support spindles  21  with the aid of a divided or split nut  24 , which nut  24  is in engagement with the threaded spindle  22 , by turning the threaded spindle  22  in its longitudinal direction. 
     A longitudinal end of a turning bar  01  is connected, via a link  26 , with the sliding pad  23 . Turning bar  01  is pivotable around a vertical axis, which is perpendicular to the plane of  FIG. 1 , with a freedom of movement of 90°, between first and second work positions.  FIG. 1  shows the turning bar  01  in a first, or “right” work position. The second, or “left” work position is indicated by a dash-dotted contour in  FIG. 1 . As can be seen in  FIG. 4 , which is taken along the section line B-B in  FIG. 1 , the link  26  comprises a flat cylindrical or disk-like body  27 , which is securely connected with a first longitudinal end of the turning bar  01  and which flat cylindrical or disk-like body  27  is extended along a link pivot axis  30  in both directions by cylindrical extensions  28  of a narrower diameter than that of the body  27 . These extensions  28  are rotatably maintained in a bore of the sliding pad  28 . 
     A link bore  29 , which extends in the plane of  FIG. 1 , is centered in, and passes through the flat cylindrical body  27  of link  26 . The link bore  29  connects a chamber  31 , which is formed in the sliding pad  23 , with a tube section  06  formed in the turning bar  01 , which turning bar tube section  06  is extending along the longitudinal axis of the turning bar  01  approximately as far as a longitudinal center of the turning bar  01 . 
     The sliding pad  23  is furthermore provided with a connector  32  for connection of the sliding pad  23  with a compressed air line, so that the interior of the turning bar  01  can be charged with compressed air via the connector  32 , the sliding pad chamber  31 , the link bore  29  and the turning bar tube section  06 . 
     The turning bar  01  has a cylindrical turning bar jacket  02 , which jacket  02  is provided with evenly distributed jacket holes  08  over its entire circumference and, except for short pieces at the turning bar longitudinal ends, over its entire axial length. A closing body  03 , in the shape of a hollow cylinder  03 , rests against an interior wall of the turning bar jacket  02  and is rotatable around the longitudinal axis of the turning bar  01 . As can be seen particularly in the sectional view, taken along the line A-A in  FIG. 1 , and represented in  FIG. 2 , the closing body  03  is provided with closing body holes  04  over half its circumference. The other half of the circumference of the closing body  03  is imperforate. The holes  04  of the closing body  03  are depicted as being aligned with a first group of holes  08  in the jacket  02 , which first group of jacket holes  08  is located on a side of the jacket  02  facing away from the support spindles  21 . In  FIG. 2  this is the half of the jacket  02  oriented down and to the left. When the turning bar  01  is charged with compressed air, the air exits from this first group of holes  08 , and in this way forms an air cushion, on which a web of material which is to be rerouted and which is looped around one half of the circumference of the turning bar  01 , can be guided essentially without friction. The remaining holes  08  of the jacket  02 , which are located on the circumference of the jacket  02 , around which the web of material does not loop, the half oriented up and to the right in  FIG. 2 , are cut off from the compressed air supply by the imperforate portion of the closing body  03 . 
     In the course of displacing the turning bar  01  from one work position into the other, the closing body  03  preferably performs a rotation through 180°, so that the group of jacket holes  08 , which are open in the one work position of the turning bar  01 , in the other work position of the turning bar  01  are located opposite the closed half of the circumference of the closing body  03 , while the jacket holes  08  of the other group are now aligned with the holes  04  of the closing body  03 . Such a coupling of the rotation of the closing body  03  to the displacement of the turning bar  01  can take place, for example, with the aid of a stationary gear ring on the link  26 , which gear ring is not specifically represented and which meshes with an exterior teeth arrangement of the closing body  03 . 
     A first turning bar threaded spindle  07 , as seen in  FIG. 3 , extends from the free end of the turning bar  01 , and in the interior of the turning bar  01  into the immediate vicinity of the turning bar end represented in  FIG. 1 , which turning bar end is connected with the link  26 . The first threaded spindle  07  is arranged offset to the side of the longitudinal axis of the turning bar  01  and extends outside the tube section  06  and is parallel with the tube section  06 . A screw thread of spindle  07  is in engagement with an interior screw thread of a first piston  09 , which first piston  09  can be displaced in the axial direction of the turning bar  01  by rotating the first threaded spindle  07 . For rotating the threaded spindle  07 , an actuating element  10 , for example a nut  10 , is attached, fixed against relative rotation, to the free end of the first turning bar threaded spindle  07  projecting from the free end of the turning bar  01 . Nut  10  is rotatable by a suitable wrench which can be used to turn the first turning bar threaded spindle  07 . The lateral faces of the first piston  09  rest tightly against the interior face of the hollow-cylindrical closing body  03 . 
     A corresponding second piston  11 , which is axially displaceable with the aid of a second turning bar threaded spindle  12  also supporting a nut  10 , is arranged at the free end of the turning bar  01 , as represented in  FIG. 3 . Each of the two pistons  09 ,  11  constitutes a limit, in the axial direction of the turning bar  01 , of the interior  13  of the turning bar  01  to be charged with compressed air via the tube section  06 . 
     The borders of the pistons  09 ,  11  facing the interior  13  of the turning bar  01  each follow the course of an edge  14  of a web of material that is looped around the turning bar  01 , i.e. they essentially follow the course of two helically-shaped sections of opposite handedness, each extending around half the piston circumference. 
     The sliding pad  23  has two arms  16 , which extend at an angle of 90° from each other and on the end of each of which arms  16  a stop  17  has been mounted, which stop  17  has a concave side  18  facing the turning bar  01 , as represented in  FIG. 2 . The two stops  17  limit the pivoting freedom of the turning bar  01  in the link  26  to exactly 90°. For a fine adjustment of the setting positions, or of the pivoting freedom, it is possible to provide an adjusting mechanism for changing the position of the stop  17  parallel in relation to the direction of the line A-A. 
     The turning bar  01  has protrusions  33 , as seen in  FIG. 1 , on two opposite ends, each of which protrusions  33  has an inclined face  34  facing the jacket  02  of the turning bar  01 . A shaft  36 , which is rotatably seated in each sliding pad arm  16 , has a square extension  37  at an end facing away from the turning bar  01 , on which square extension  37  an appropriate wrench, for use in rotating or pivoting the shaft  36 , can be placed. On its opposite end facing the turning bar  01 , the shaft  36  supports a bolt  38 , which bolt  38  is represented on the left arm  16  of the sliding pad  23  and on the right arm  16  of the sliding pad  23 , in alternate positions that are pivoted by 90° with respect to each other. 
     The bolt  38  of the right arm  16  extends behind the inclined face  34  of the protrusion  33  and in this way acts as a lock and keeps the turning bar  01  pressed against the right stop  17 . The bolt  38  itself has an inclined face which, in the locked position, is pushed against the inclined face  34  of the protrusion  33 . It is achieved, because of the inclined course of these inclined faces  34 , that, by pivoting the bolt  38  out of the vertical position represented at the right arm  16 , and by pivoting of the bolt  38  into the horizontal position represented at the left arm  16 , and with the turning bar  01  being fixed in place against the stop  17 , the bolt  38  can already be engaged behind the protrusion  33  before the turning bar  01  rests directly against the stop  17 , and that the locking of the turning bar  01  is free of play. 
       FIG. 5  shows a top plan view of a turning device in accordance with a second preferred embodiment of the present invention. The turning bar  01 , represented in this second preferred embodiment in its entirety, the sliding pad  23 , as well as the support spindle  21  and the threaded spindle  22 , are the same as those described above in connection with  FIGS. 1 to 4 . The sliding pad  23  also has left and right stops  17  for limiting the pivoting freedom of the turning bar  01 . The housing of a linear actuator  41 , for example a reciprocally operating pneumatic cylinder  41 , is pivotally suspended from a second, actuator support arm  39 . The suspension of the cylinder  41  acts on that end of the cylinder  41  at which a piston rod  42  also exits from the housing of the cylinder  41 . The piston rod  42 , in turn, is hingedly connected with the turning bar  01 . The turning bar  01  can be changed between its first and second work positions, against one or the other of the two stops  17 , by retracting and extending the piston rod  42 . Turning bar  01  can be immovably maintained in one of these first and second work position by arresting the piston rod. 
     This second preferred embodiment of the turning device in accordance with the present invention permits a remote-controlled switching of the turning bar  01  between its two work positions without direct access of an operator to the turning bar being necessary. 
       FIG. 6  shows a portion of a turning device in accordance with a third preferred embodiment of the present invention. Again, the turning bar  01 , its protrusions  33 , the link  26  and the sliding pad  23  are the same as described in connection with  FIGS. 1 to 4 . Only one sliding pad arm  16  is represented in  FIG. 6 . A second sliding pad arm  16 , which is arranged symmetrically to depicted arm  16  is also provided. In addition to the stop  17 , the sliding pad arm  16  supports a linear actuator  43 , which linear actuator  43  can be electromagnetically operated or, as in the case in connection with  FIG. 5 , linear actuator  43  can be a pneumatic cylinder  41 . The linear actuator  43  supports a bolt  38 , which is displaceable in a direction that is parallel with the longitudinal axis of the turning bar  01 . The bolt  38  has first and second inclined faces  44 ,  46 , of which the first inclined face  44  of bolt  38  is oriented parallel with the inclined face  34  of the protrusion  33 , and the second inclined face  46  of bolt  38  extends almost perpendicular to, or vertically with respect to the movement direction of the bolt  38 . Thus, when the turning bar  01  is moved into the contact position represented in  FIG. 6 , the protrusion  33  initially encounters the inclined face  46  and slides along it, in the course of which sliding motion the bolt  38  is urged backward against a force exerted by the linear actuator  43 . Once the protrusion  33  is past the inclined face  46 , the bolt  38  springs forward again and the inclined faces  34 ,  44  come into contact with each other, so that the turning bar  01  is arrested in the contact position represented in  FIG. 6 . For pivoting the turning bar  01  into the respectively other position, the linear actuator  43  is triggered in such a way that it retracts the bolt  38  and releases the turning bar  01 . 
     While preferred embodiments of a turning device, in accordance with the present invention, have 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 web being turned, the source of supply of the compressed air, the number and size of the jacket holes, and the like could be made without departing from the true spirit and scope of the present invention which is accordingly to be limited only by the appended claims.