Abstract:
A device that is useable to clamp a rotatable shaft or spindle and which is provided with cams or pressure pieces, to retain or to tension packings on a cylinder, is provided. The shaft or spindle can be both rotated about an axis of rotation, as well as clamped against rotation by the device. The device can be pivoted with respect to the shaft or spindle about a pivot axis which is essentially perpendicular to the axis of rotation of the shaft or spindle. The pivotable device can be provided as a pawl or lever that interacts with a pair of stops to hold it in a shaft or spindle locking position.

Description:
FIELD OF THE INVENTION 
     The present invention is directed to a device for clamping and/or tensioning. More specifically, the present invention is specifically directed to a device for clamping or tensioning a plate or a packing on a cylinder. 
     BACKGROUND OF THE INVENTION 
     DE 195 09 561 C2 discloses a device for clamping plates, which has a swiveling spindle. The plates are frictionally held between a channel wall and pressure cams that are arranged radially in the spindle. Clamping is performed by turning the swiveling spindle until the cams act almost normally on the plates resting against the channel wall. In a similar manner, DE 40 05 093 C1 shows an eccentrically seated spindle, which frictionally clamps the plates between its surface shell and the channel wall when the spindle is turned. 
     A device for actuating a tensioning device is known from DE 34 01 760 A1, in which the tensioning spindle is structured as a profiled shaft. Tensioning takes place by turning the head of the tensioning spindle, which projects past the end face of the cylinder, and which displaces a tensioning strip in the circumferential direction. The spindle is non-positively secured against an automatic return movement by pressing the surface of a pin of the spindle into a bracket. 
     U.S. Pat. No. 4,495,865 shows a device for accomplishing the positive arresting of a device for tensioning packings on cylinders by turning a spindle. A crown gear is assigned to one of the ends of the spindle. Arresting is performed by the use of a blade, which is placed nearly tangentially against the crown gear. The shape of the teeth and the arrangement of the blade have been selected in such a way that turning of the spindle in the tensioning direction is possible, but a return movement is prevented. To release the device, the blade is pivoted away from the crown gear by actuating a lever that is assigned to the blade. 
     DE 44 42 300 A1 also shows a device for tensioning packings, that has an arresting device which, in the operating state, permits turning of the tensioning device in the tensioning direction, but blocks a return movement. Tensioning and arresting, or releasing, here takes place by the use of a single actuating device that is arranged in an extension of the spindle and which is turned for tensioning the packing in the circumferential direction of the spindle, and for arresting/releasing the spindle is moved axially in respect to the spindle axis. No limitation of the travel or force in the tensioning direction is provided. 
     DE 29 10 880 C2 also discloses a device for tensioning a packing, wherein the tensioning of a packing and the arresting of a shaft takes place by the use of a single device. Tensioning and arresting by the utilization of the friction of a threaded bolt arranged in a screw thread takes place by the same movement. 
     A device for clamping/tensioning a packing and for arresting the device is known from U.S. Pat. No. 4,417,517. Tensioning is performed by the use of swiveling a shaft, and arresting is accomplished by the use of a lever which must be specifically actuated. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is directed to providing a device for clamping and/or tensioning. 
     In accordance with the present invention, this object is attained by providing a packing clamping or tensioning device in which packing clamping and tensioning, as well as the arresting of a shaft with respect to its axis of rotation, can be performed by a single device. For clamping and tensioning, this single device can be rotated about an axis that is parallel with the rotational axis of the shaft. For arresting movement of the shaft, the device is pivotable about a pivot axis that is perpendicular to the axis of rotation of the shaft. 
     An advantage to be achieved by the present invention resides, in particular, in that one single device permits both clamping, or tensioning of packings and, at the same time, the positive arresting in the desired position of the clamping device. An actuation of separately provided devices for arresting, or releasing, and for clamping, or tensioning, is not required. The device for clamping or tensioning, in accordance with the present invention, is simple to operate and can be accurately and dependably arrested in respect to available locking mechanisms. 
     A further advantage of the device of the present invention is that arresting is provided by the provision of a positive connection, wherein the effective surfaces take place nearly perpendicularly to the circumferential surface and therefore normal in respect to the possible movement or force direction of the shaft or spindle. Release of the subject device, in response to centrifugal forces, or to fluctuations or micro-movements, as is possible with the use of non-positive connections or with the use of resilient lever mechanisms, cannot occur. 
     Arresting can be performed in a simple self-locking manner. In the operating state of the cylinder, i.e. in the state of rest of the device for clamping and/or tensioning, the device is maintained positively arrested. 
     The arrangement of the present invention, with the arresting device acting positively in both directions of rotation of the spindle, is particularly advantageous. This permits an exact, reproducible positioning of the shaft or spindle, and thus of the surfaces working together with the packing, and further permits a defined position, independently of pretensioning of the device or the packing. The position of the spindle is important, in particular, for non-positive or for positive holding or tensioning with the aid of profiled shafts, cams or gripping members on shafts. A small positional change of the surface in the circumferential direction, which works together with the packing, or an initially not quite exactly set position might cause the “opening” of the device, in particular, if the operation is performed at dead center (unstable equilibrium). By arresting the spindle in both adjustment directions, the unintentional displacement of the spindle by forces or movements which are oriented out of the channel, as well as forces or movements directed into the channel, is prevented. The former are caused, for example, by the pulling force of the packing or by a centrifugal force. The latter are caused for example, by changes in length or by an evening-out of the packing over the circumference of the cylinder. If there is only a frictional connection between the packing and the surface of the spindle acting together with the packing, the packing can move further into the channel without the spindle being displaced in the circumferential direction and therefore turned out of its desired position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred embodiment of the present invention is represented in the drawings and will be described in greater detail in what follows. 
     Shown are in: 
     FIG. 1, a cross-sectional view through a channel of a cylinder which is provided with a clamping and/or a tensioning device, 
     FIG. 2, an isometric view of the device for clamping and/or tensioning in accordance with the present invention, 
     FIG. 3, a cross-sectional view through the device for clamping and/or tensioning in an arrested position A, and in 
     FIG. 4, a cross-sectional view through the device for clamping and/or tensioning, in accordance with the present invention, in a released position B. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A device for the non-positive or for the positive holding and/or tensioning of at least one packing  03 , for example in the form of a printing plate  03 , on a formed cylinder  01 , or a rubber blanket  03  on a transfer cylinder  01 , is arranged in an axially extending channel  02  of a cylinder  01 , for example a formed or a transfer cylinder  01  of a printing press. 
     The actuation of the device for tensioning or holding the packing  03  is performed through a shaft  04 , for example a spindle  04  which is provided with thrust pads, and which shaft or spindle  04  is rotatably seated in the channel  02  of the cylinder  01 . 
     The channel  02 , which extends parallel with the cylinder axis of rotation, has a slit  06  on the surface shell of the cylinder  01 , and a bore  07  located in the interior of the cylinder  01  and connected with the slit  06 . A width b 06 , for example b 06 =1 mm, of the slit  06  has slightly more than twice the thickness of the packing  03 . The shaft  04 , which, in the depicted configuration is a rotatable spindle  04 , is arranged in the bore  07 . 
     In order to accomplish the clamping of the packing  03 , both ends of the packing  03  are fed into the slit  06  and are clamped by rotating the spindle  04  with the aid of the clamping and/or tensioning device of the present invention. The spindle  04  is provided with thrust pads  08  for use in clamping or tensioning the ends of the packing  03 . A hook strip  08 , for example, which is arranged in a recess  09 , formed, for example as a groove  09 , and extending in the axial direction on the circumference of the spindle  04 , is used as the thrust pad  08  for the non-positive holding of the packing  03 . The hook strip  08  is pressed in a radial direction, with respect to the spindle  04 , out of the spindle  04  and against the packing  03  by resilient elements  11 , for example by compression springs  11 . The compression springs  11  are located in blind bores  12 , which are spaced apart from each other in the axial direction of the spindle  04  and are arranged in the bottom surface of the groove  09 . The head of the hook strip  06 , which cooperates with the packing  03 , can be provided with a continuous hook  13 , or with several individual hooks  13  that are spaced apart from each other in the longitudinal or axial direction of the spindle  04 , this hook  13  or these spaced hooks  13 , in the clamping and tensioning device depicted in FIG. 1, act together with the edge  14  of the packing  03 , or with corresponding recesses  16  in the packing  03 , for releasing the packing  03 . 
     The non-positive connection between a wall  17 , that is formed in the cylinder as part of the slit  06 , and leading and trailing ends of the packing  03 , together with the hook or hooks  13  arranged on the head of the hook strip  08 , is greatest when the force exerted by the compressing springs  11 , through the hook strip  08 , acts perpendicularly on the ends of the packing  03 . 
     The shaft  04  can also be a profiled shaft, such as, for example, an eccentric shaft, a shaft or spindle provided with cams, or an eccentrically seated shaft or spindle. The shaft  04 , when it is turned, works either directly with the packing  03  in a frictionally connected or non-positive way by use of its active surface, or it actuates a movable mechanism, which mechanism, in turn cooperates with the packing  03 . The surface of the shaft  04 , which works either directly with the packing  03  in a frictionally connected or non-positive way with the packing  03 , or which works with the intermediate movable device, is identified as the active surface of the shaft or spindle  04 . 
     The device for clamping and/or tensioning, in accordance with the present invention, includes a recess  18  in a surface shell  19  of the shaft  04 , in which a pivotable lever  21  is arranged, all as seen in FIG.  2 . The pivot axis  22  of the lever  21  extends nearly perpendicularly with respect to the rotational axis  23  of the shaft or spindle  04 . For tensioning or clamping the packing  03 , the shaft  04  is turned around its rotational axis  23 , in an advantageous manner, with the aid of the lever  21 . For arresting or releasing the shaft  04 , the lever  21  is pivoted around its pivot axis  22  as seen in FIGS. 3 and 4. The shape and position of the lever  21  is structured in such a way that in a first position, which is the arrested position A shown in FIG. 3, the lever  21  acts in a positive manner together with surfaces  24  and  26  of a pair of detents, for example the lateral surfaces  24  and  26  of a groove  27  that is fixed in the cylinder. In this arrested position A, the shaft  04  is fixed in both rotational directions in relation to its rotational axis  23 . In a second position, which is the released position B shown in FIG. 4, the lever  21  lies free with respect to the cylinder  01  and therefore permits turning of the shaft  04 . 
     In the depicted preferred embodiment, the recess  18  at one end of the shaft  04  is configured as a groove  18 , which extends continuously through the end of the shaft  04  perpendicularly in relation to the rotational axis  23  of the shaft  04 . The groove  18  can also be arranged on a bearing journal assigned to the shaft  04 , or on another extension assigned to the shaft  04 . In the preferred embodiment, the groove  18  is located at the end face of one end of the shaft  04  and divides that end face into two shaft legs  28  and  29  with opposite leg surfaces  31  and  32  pointing inwardly toward the rotational axis  23  of the shaft  04 . Groove  18  also defines a groove inner wall surface  34  that is located between the two legs  28  and  29  and pointing in the direction of the outer end  33  of the shaft  04 . Each of the legs  28  and  29  has an outward oriented surface  36  and  37 , which surfaces  36  and  37  are, in the present configuration, a part of the shaft surface shell  19 . 
     A bolt  38 , which extends in a direction corresponding to the pivot axis  22  and to which the lever  21  is swivelably attached, is arranged in the groove  18 . The bolt  38  extends between the surfaces  31  and  32  of the legs  28  and  29  in the interior of the groove  18  and is preferably perpendicular with respect to the rotational axis  23  of the shaft  04 . Bolt  38  allows pivoting of the lever  21  in a plane located parallel with the rotational axis  23  of the shaft  04  and perpendicular in respect to the pivot axis  22  of lever  21 . The bolt  38  can be a shaft  38  passing through the lever  21  and can be of one piece construction or can be divided, and arranged extending on both sides of the lever  21 . It can be non-positively or positively connected in the legs  28  or  29  or in the lever  21 , wherein the rotatable seating, for example embodied as bushings or bearings, is then arranged correspondingly, in a first case, the lever  21  or, in a second case, in the legs  28  and  29 . 
     In the depicted preferred embodiment, the lever  21  is embodied as a two-armed lever  21 , with respect to the pivot axis  22 . The bolt  38 , acting as a fulcrum, defines a lever arm  39  to be actuated and a lever arm  41 , which acts as a ratchet  41 . The lever  21  has two lateral surfaces  42  and  43 , which lie nearly parallel to opposite surfaces  31  and  32  of the legs  28  and  29 . Lever  21  also has an inner end surface  44  which is facing the groove inner wall surface  34  and a lever outer end surface  46  located diametrically opposite the lever inner end surface  44 . In the preferred embodiment, the lever  21  is approximately cuboid and it has top and bottom ends  47  and  48  on opposite ends. 
     The lever  21  can also be embodied as a one-armed lever. In this case, the ratchet  41  is for example a protrusion  41 , which projects laterally out of the outer surface  46  on the lever arm  39  and which, in the arrested position A, enters into the groove  27  fixed on the cylinder. 
     The lever top end  47 , assigned to the lever arm  39  to be actuated, can have an opening  49 , for example a bore  49 , into which an actuating device  51 , for example an actuating arbor  51 , is positively inserted for use in extending the lever arm  39 , as seen in FIG.  3 . The positive connection can also be configured in the opposite manner by the use of an opening  49  in the actuating arbor  51  and by a correspondingly shaded protrusion on the lever arm  39  portion of lever  21 . 
     The dimensions and the position of the lever arm  41  acting as a ratchet  41  are selected in such a way that in the released position B the lever bottom end face  48  terminates flush with the surface shell  19 , for example, or at least does not project past it, but in the arrested position A this bottom end face  48  projects past the surface shell  19  and acts positively together with the lateral surfaces  24  and  26  of the groove  27 . In the depicted preferred embodiment, the ratchet  41  is a part of the cuboid two-armed armed lever  21  and has a length l 41  and a width b 41 . The bolt  38 , arranged perpendicular in respect to the rotational axis  23  of the shaft  04 , passes perpendicularly through the surfaces  42  and  43  of the lever  21 . The length l 41  of the ratchet  41  has been selected to be approximately equal to the radius r 04  of the shaft  04 , so that the lever bottom end face  48  extends flush nearly in an imagined extension of the surface shell  19 . When swiveling the lever  21  over an angle β into the arrested position A, the edge defined by the surfaces  48  and  46  moves out of the imagined course of the surface shell  19 . It is possible, in an advantageous manner, for the surface  46  of the cuboid lever  21  to be beveled by the angle β in the area of the lever arm  39  in such a way that, in the arrested position A, the lever  21  does not project out of the end face of the cylinder  01 . In the same way, the surface  44  of the cuboid lever  21  can be beveled by the angle β in the area of the lever arm  41  in such a way that, in the arrested position A, the lever  21  does not project into the shaft  04 . 
     The position and shape of the ratchet  41  are matched to the shape and distance of the surfaces  24  and  26  which are respectively acting together with the ratchet  41  as a detent, as well as to the positioning of the shaft  04  in the cylinder  01 . 
     In the depicted preferred embodiment, the end of the shaft  04 , which projects from the channel  02  and which is provided with the groove  18  at its end, is positively seated, rotatable around the rotational axis  23 , in a bore  52  of the end wall  53  of the cylinder  01 . However, for the purpose of operating the lever  21  that is arranged in the groove  18 , the shaft  04  is not completely surrounded by the front wall  53  of the cylinder  01 . The opening angle a of a channel in the end wall  53  of the cylinder  01  depends on the required travel arc of the lever  21  for actuating the shaft  04  and, for example, can be 70°. 
     The groove  27 , acting together with the ratchet  41 , is arranged in the bore  52  parallel with the rotational axis  23  and has a base  54  and the two previously discussed lateral surfaces  24  and  26 , which act together with the surfaces  42  and  43  of the ratchet  41 . It is also possible for several grooves  27  to be arranged in the bore  52  in the circumferential direction. 
     The ratchet  41  can also act together with different surfaces  24  and  26  arranged on the cylinder  01 , which in the arrested position A positively absorb the force transmitted via the surfaces  42  and  43  of the lever  21  and which are acting tangentially in relation to the surface shell  19  of the shaft  04 . This can be, for example, a segment of a hollow wheel with teeth on the inside, and having respective tooth flanks as the surfaces  24  and  26 , and with a ratchet  41  embodied as a trapezoidal or triangular prism, working together with them. 
     The inclinations of the surfaces  24  and  26  working together with the lever  21  as detents, for example embodied as lateral surfaces  24  and  26  of a groove  27 , are arranged, in an advantageous manner, nearly parallel with the surfaces  42  and  43  of the lever  21  when the shaft  04  and the lever  21  are in the arrested position A. In an advantageous manner, the surfaces  42 ,  43 ,  24  and  26  approximately extend on a plane parallel with the rotational axis  23 , and thus in the pivotal plane of the lever  21 . It is possible to achieve a positive connection, fixed against a possible rotation of the shaft  04 , together with as even as possible a surface pressure, for example, by the arrangement of the surfaces  42 ,  43 ,  24  and  26  in a plane extending nearly parallel with the rotational axis  23  and perpendicularly with respect to the tangent of the surface shell  19  of the shaft  04 . In order to avoid play in case of a non-positive connection, it is possible to select the width b 41  of the ratchet  41  to be nearly equal to the width b 27  of the groove  27 , or to be nearly equal to the clear distance between the surfaces  24  and  26  respectively, which are acting as detents. 
     The shape of the end of the ratchet  41  acting together with the cylinder groove  27  with ratchet lateral faces  42  and  43  approaching each other in a slightly wedge-shaped manner in the direction toward the groove  27 , is advantageous. In this arrangement, the width b 27  of the groove  27 , or the clear distance between the surfaces  24  and  26  has been selected to be greater than the narrow side of the lever  21  facing the groove  27 , and less than the wider side of the wedge-shaped end of the ratchet  41 . In the arrested position A, the ratchet  41  is located as deeply as possible in the groove  27  and constitutes a positive, play-free connection with respect to the possible swivel direction of the shaft  04 . 
     In a preferred embodiment, the lever  21  is in the arrested position A when it is not in operation and it prevents the unintentional rotation of the shaft  04 . For this purpose, an element  56  with a resilient action essentially parallel with the rotational axis  23  is arranged in the groove inner wall surface  34  of the shaft  04  and cooperates directly or indirectly with the lever inner end surface  44  in the area of the lever arm  39 . In the depicted configuration, the surface  44  has a blind bore  57 , in which a spring  56  and a ball  58  are arranged. The spring  56  is supported on the bottom of the blind bore  57  and presses the ball  58 , which is arranged in the mouth of the blind bore  57 , against the surface  44  of the lever arm  39 . 
     In all configurations, the recess  18 , an adjustable device  21 , configured as a lever  21 , and the two surfaces  24  and  26 , each acting together with the lever  21  as detents, mutually affect each other in their detailed shaping and arrangement. The arrangement of a lever  21 , which is pivotable in a plane that extends nearly parallel with the rotational axis  23  of the shaft  04  and that has a ratchet  41  which, by use of its lateral surfaces  42  and  43  cooperates with the surfaces  24  and  26  each acting together with the other as detents, is common to all possible configurations. In the arrested position A of the lever  21 , the shaft  04  is fixed in both directions in respect to its rotational axis  23 . In a different configuration, the surfaces  24 ,  26 ,  42  and  43  can also be embodied as contact lines or as contact points. 
     It is also possible, for example via a gear of toothed wheels, to arrange the rotational movement for clamping/tensioning not directly around the rotational axis  23  of the shaft  04 , but around an axis parallel with this rotational axis. 
     The mode of functioning of the device in accordance with the present invention, for actuating a clamping and/or tensioning device, is as follows: 
     For changing the packing  03  on the cylinder  01 , the lever  21 , which is in the arrested position A shown in FIG. 3, is pivoted into the released position B shown in FIG. 4 by pivoting the lever arm  39  against the force of the resilient element  56 . In the process, the ratchet  41  moves out of the groove  27  and is in the released position B. The shaft  04 , for example the rotatable spindle  04 , can now be rotated, by movement of the lever arm  39 , around its rotational axis  23  with or without use of the actuating arbor  51 . In the preferred embodiment, the shaft  04  is initially rotated into the direction in which the hooks  13  of the hook strip  08 , arranged on the spindle  04 , extend below the edge  14 , or the recesses  14  of the packing  03 . Thereafter, the spindle  04  is rotated in the opposite direction, whereupon the hooks  13  push the packing  03  out of the channel  02 . 
     For clamping, or tensioning a newly installed packing  03 , the shaft  04 , for example the spindle  04 , is initially placed in a position in which the hooks  13  are not in the channel  02  that receives the end of the packing  03 . In the depicted configuration, the spindle  04  is arranged in this position in such a way that the hooks  13  point radially out toward the surface of the cylinder  01 , and not into the slit  06 . Both ends of the packing  03  are introduced through the slit  06  into the channel  02  so that they come to rest between a wall  17  or  53 , fixed on the cylinder, of the slit  06  and the spindle  04 . Thereafter, the spindle  04  is rotated around its rotational axis  23  by use of the lever arm  39  to the extent that the ratchet  41  reaches the position defined by the groove  27  in the cylinder  01 . In this position, the hooks  13  act together with the packing  03 , and the force of the compression springs  11  acts nearly normally on the packing  03 . With the release of the lever arm  39 , the ratchet  41  is swiveled, via the resilient element  56 , into the groove  27  and is maintained there in a self-locking manner. The shaft  04  is now fixed in the predetermined position against rotating in either possible direction. 
     While a preferred embodiment of a device for clamping or tensioning a packing on a cylinder 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 a number of changes in, for example the overall size of the cylinder, the type of printing press the cylinder is used with, 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.