Abstract:
A press with a capability to adjust for multiple roll diameters, comprising: a frame; a mounting assembly with at least one adjusting arm for mounting a roll therein, the adjusting arm being moveable to change position relative to the frame in correspondence to a change in diameter of the roll; a guard assembly that provides a guard across a pinch point between a roll and another element, the guard assembly being moveably attached to the at least one adjusting arm and to a portion of the frame to automatically adjust a position of the guard when the at least one adjusting arm is moved in order to maintain a spacing between the guard and the roll within a predetermined range.

Description:
1. FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to the field of presses, and more particularly, to presses with structures for providing an adjustable pinch point guard.  
         2. BACKGROUND OF THE INVENTION  
         [0002]    It is frequently necessary to have a pinch point guard covering an area to prevent pinching between a roll and another element. But a problem arises because using an area pinch point guard that covers a whole print area prevents cleaning the printing plate or diecut plate without stopping the press.  
         SUMMARY OF THE INVENTION  
         [0003]    Briefly, one embodiment of the invention comprises a press with a capability to adjust for multiple roll diameters, comprising: a frame; a mounting assembly with at least one adjusting arm for mounting a roll therein, the adjusting arm being moveable to change position relative to the frame in correspondence to a change in diameter of the roll; a guard assembly that provides a guard across a pinch point between a roll and another element, the guard assembly being moveably attached to the at least one adjusting arm and to a portion of the frame to automatically adjust a position of the guard when the at least one adjusting arm is moved in order to maintain a spacing between the guard and the roll within a predetermined range.  
           [0004]    In a further embodiment of the present invention, the guard assembly is automatically adjusted to also maintain a spacing between the guard and the other element within a predetermined range.  
           [0005]    In a further embodiment of the present invention, the guard comprises a guard bar.  
           [0006]    In a further embodiment of the present invention, the guard assembly comprises at least one guard arm for holding said guard, with at least one guard arm being pivotally attached at one part thereof to a pivot axis on said at least one adjusting arm, and attached at a second point adjacent to the guard via a guide slot.  
           [0007]    In a further embodiment of the present invention, there are two adjustment arms in the mounting assembly and two guard arms in the guard assembly, with the each guard arm pivotally attached to a different one of the guard arms.  
           [0008]    In a further embodiment of the present invention, the guard arm has substantially the shape of an S.  
           [0009]    In a further embodiment of the present invention, the guide slot is a radial slot centered on an anilox roll.  
           [0010]    In a further embodiment of the present invention, guide slot is disposed in the frame.  
           [0011]    In a further embodiment of the present invention, the guard arm comprises at least two pieces.  
           [0012]    In a further embodiment of the present invention, the mounting assembly is moved by a power element.  
           [0013]    In a further embodiment of the present invention, the press is a printing press.  
           [0014]    In a further embodiment of the present invention, the press is a diecutter.  
           [0015]    In a further embodiment of the present invention, a method is provided for adjusting pinch point guard in a press, comprising the steps of: moving a mounting assembly for a roll relative to a frame in correspondence to a change in diameter of the roll; and automatically moving a guard bar in unison with the movement of the mounting assembly to adjust a position of the guard bar to automatically maintain a spacing between the guard bar and the roll and between the guard and another element within a predetermined range.  
           [0016]    In a further embodiment of the present invention, the step of automatically moving a guard bar comprises causing the guard bar to follow a radial motion. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    [0017]FIG. 1 is a schematic perspective drawing of a preferred embodiment of the present invention illustrated with an impression roll, and anilox roll and a plate roll.  
         [0018]    [0018]FIG. 2 is a perspective schematic diagram of a preferred embodiment of the present invention illustrated with a small diameter plate roll.  
         [0019]    [0019]FIG. 3 is a perspective schematic diagram of a preferred embodiment of the present invention illustrated with a large diameter plate roll.  
         [0020]    [0020]FIG. 4 is a schematic block diagram of a preferred embodiment of the frame, mounting assembly and, guard assembly for the present invention.  
         [0021]    [0021]FIG. 5 is a specific schematic diagram of a preferred embodiment of the guard assembly of the present invention.  
         [0022]    [0022]FIG. 6 is a schematic diagram of a printing press with an anilox roll, an impression roll, and positioning for a small plate roll and positioning for a large plate roll.  
         [0023]    [0023]FIG. 7 is a graph of the gap between the guard and the anilox roll and the plate roll versus number of teeth in the diameter of these rolls. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]    Referring now to FIG. 1, there is shown a press  10  in accordance with a preferred embodiment of the present invention. The press  10  comprises a frame  12 , a mounting assembly  13 , 14 , and a guide assembly including elements  22  and  24 . The mounting assembly includes at least one adjusting arm  13 , and in a preferred embodiment, two adjusting arms  13  and  14 , for mounting a roll  16  therein. The adjusting arm  13  and/or  14  is moveable to change position relative to the frame  12  in correspondence to a necessary change to accommodate a range of diameters of the roll  16 . In a preferred embodiment, this movement is achieved in part by a power element  34 , such as an air cylinder for example, which drives the arm  14  for upward movement, with gravity used for the downward movement. In a preferred embodiment, the arm(s)  13 , 14  rides on wheels  32  in a grooved slot  31 . Accordingly, the power element  34  causes the arm  13  to ride up, with gravity used for the downward movement in the slot  31 . A comparable power element (not shown) would be utilized to drive the arm  14 .  
         [0025]    It should be noted that the context for the example shown in FIG. 1 is a printing press with an anilox roll  18 , an impression roll  20 , and a plate roll  16 . However, the present invention is in no way limited to configurations that use impression and anilox rolls, but has broad applicability to configurations, including diecutting configurations, where a range of roll diameters are utilized.  
         [0026]    The guard assembly comprises in a preferred embodiment a guard  22  and at least one arm  24 . In a preferred embodiment, the guard  22  comprises a bar. A preferred embodiment of this guard assembly is shown in FIG. 5. It can be seen that the at least one guard arm  24  has an S shape in order to clear the plate roll  16  and the impression roll  20  shown in FIGS.  12 , and  3 . It should be understood that the guard arm  24  can take other shapes depending on what other structures are in adjacencies and must be cleared during movement.  
         [0027]    [0027]FIG. 2 illustrates the preferred embodiment of the present invention with a small diameter print roll  16 (A).  
         [0028]    [0028]FIG. 3 illustrates the preferred embodiment of the present invention with a large diameter print roll  16 (B).  
         [0029]    [0029]FIG. 4 illustrates the preferred embodiment showing only the frame  12 , and one movable adjusting arm  14 (B), and with the guard assembly elements  22  and  24  in place. It can be seen that the guard arm  24  is attached at one end to the guard  22  and at substantially the same end to an adjustable attachment region  26  in the frame. In the embodiment shown in the figure, the region  26  comprises a slot. The guard arm  24  is also attached to a section  28  of the adjusting arm  14 . The section  28  is also shown in FIG. 5. In a preferred embodiment the attachment to the adjusting arm(s)  13 , 14  is by means of a pivot axis  30 , although the invention is not so limited, and other methods of attachment are contemplated.  
         [0030]    In the preferred embodiment of the present invention shown in FIG. 1, the guard arm  24  pivotally attaches at one part thereof to the pivot axis  30  (shown in FIG. 4) on the adjusting arm  14 . Additionally, the guard arm  24  is attached at a second point adjacent to the guard  22  by means of a guide slot  26 . In the embodiments shown, the guide slot  26  is disposed in the frame  12 , and a portion of or an extension  40  from the ends of the guard  22  ride inside the guide slot  26 . However, this guide slot  26  can also be disposed in the guard arm  24  and a protrusion or other element in the frame  12  could ride in that slot. The guide slot will take a configuration depending on the configuration and the movement desired for the guard  22 . In a preferred embodiment, the guide slot  26  is a radial guide slot which is centered on the anilox roll  20 .  
         [0031]    With the way that the arm  24  is connected between the adjusting arm  14  and the fixed frame  12 , when the adjusting arm  14  moves upward, then the guard arm  24  rotates on the pivot axis  30  and moves outward following a predetermined guide path defined by the slot  26 .  
         [0032]    [0032]FIG. 6 is a schematic diagram showing a small plate roll  16 (A) and a large plate roll  16 (B) in the context of an anilox roll  18  and an impression roll  20 . One end of the guard  22 , shown as position  22 (B), illustrates the position of the guard  22  when the large plate roll  16 (B) is utilized. It can be seen that the position of the guard  22  is at the pinch point just before the large plate roll  16 (B) and the anilox roll  18  meet. For this position  22 (B) of the guard  22 , the guard arm  24 (B) is shown connecting to the pivot point  30 (B) in the adjusting arm  14 .  
         [0033]    [0033]FIG. 6 also shows in schematic format the configuration of the preferred embodiment when a small plate roll  16 (A) is utilized in combination with the anilox roll  18  and the impression roll  20 . In this case, the adjusting arm  14  has ridden down the frame  12  to place the small plate roll  16 (A) in contact, or substantially in contact with the anilox roll  18  and the impression roll  20 . This downward movement of the adjusting arm  14  is represented by the new pivot point  30 (A). The guide arm  24 (A) is shown placing the guard  22  at the position  22 (A), to again be at the pinch point just before the small plate roll  16 (A) and the anilox roll  18  touch or substantially touch. It should be noted that for purposes of ease of illustration the guide arm  24  has been represented as the straight line  24 (A) for the positioning to accommodate the small plate roll  16 (A), and a straight line  24 (B) for the positioning to accommodate the large plate roll  16 (B). It can be seen that the arc shown in FIG. 6 between the positions  22 B and  22 A represents the slot  26 . A web  50  is shown in FIG. 6 for purposes of explanation only. The web can take a variety of other positions, depending on the configuration of the press.  
         [0034]    Referring now the FIG. 7, there is shown a plot of pinch point gap data for a preferred design. The vertical axis in the figure represents the distance in millimeters between the guide  22  and the anilox roll  20  and the plate roll  16 . The horizontal axis represents the number of teeth on the outer parameter for the plate roll  16 , and indicates that the number of teeth increase as the plate roll diameter increases. The square dots represent data points for the gap between the guard  22  and the plate roll. The diamond points represent data points for the gap between the guard and the other element, which could be an anilox roll. It can be seen that a spacing is maintained between the guard  22  and the plate roll  16  within a predetermined range of variation. Likewise, it can be seen that the spacing between the guard  22  and the other element, which in this case is an anilox roll, is also maintained within a predetermined range, which may vary from predetermined range for the plate roll.  
         [0035]    The curve of the guide slot  26  in order to achieve a gap within the predetermined range is obtained by using an iterative process of setting a curve dimension and calculating the gaps between one of the rolls or between both rolls and the guard. A PRO/E datum curve was created. It should be noted that this curve will be different for different configurations of a press. It was found that by decreasing the vertical pivot location length caused the pinch point guard  22  to move left in the slot. It was also found that increasing the horizontal pivot location length causes the pinch point guard  22  to change more radically relative to the plate roll  16 , i.e., the pinch point guard gap distances were larger and the valleys grew deeper.  
         [0036]    The present invention in a preferred embodiment has been disclosed utilizing a guide slot  26 . However, the invention is not so limited. By way of example, the guard arm  24  may be comprised of two or more arms connected at pivot points therebetween. Accordingly, the attachment of the guard arm  24  to the frame  12  could be affixed to an axis, rather than to a slot.  
         [0037]    It can be seen that the present invention facilitates the automatic placement of a guard across a pinch point between a roll and another element without the need to place an area guard around the entire press area. Accordingly, this local pinch point guard permits an operator to clean a printing plate or die cut roll without stopping the press. The guard  22  is automatically adjusted for any roll cylinder diameter. Accordingly, the guard automatically maintains a proper gap clearance within a predetermined range between the guard bar and the roll and between the guard bar and another element such as an anilox roll. The guard bar minimizes the obstruction of viewing an access for the area. Additionally, the guard allows a non-standard web path to be created without interfering with the guarding mechanism. It can be seen that the guard  22 , in one embodiment, does not allow a gap of more than 4 mm between the guard and either roll or element.  
         [0038]    The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the concise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from the practice of the invention. The embodiment was chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto, and their equivalents.