Sheet separating device

Information

  • Patent Grant
  • 6168148
  • Patent Number
    6,168,148
  • Date Filed
    Friday, March 19, 1999
    25 years ago
  • Date Issued
    Tuesday, January 2, 2001
    23 years ago
Abstract
The apparatus for separating a flat product from a pile of flat products, has a sucker mechanism with an upper and a lower part. The upper part is connected to a first link joint of a central lever and the lower part is connected to a second link joint of the central lever. The central lever is rotatable about an axis which extends through the central lever. The axis is movable along the central lever, in order to change the position of the pivot point of the central lever.
Description




BACKGROUND OF THE INVENTION




FIELD OF THE INVENTION




This invention relates to an apparatus for separating flat products from a pile of flat products, the apparatus comprising a sucker mechanism having an upper and a lower part.




In the technology of building books, including booklets, magazines, periodicals, and the like, the use of collating systems is well known. Those systems typically have a transporting device on which individual flat products, such as signatures or sheets, are gathered to build a book-block set, which then is finished and bound. Typically, a number of feeders are arranged along the transporting device, each of the hoppers comprising a feeding mechanism for feeding an individual flat product from a pile of signatures onto the transporting device, in order to gradually build up the book-block set or to insert a supplement sheet into a pocket of a pocket feeder or into a newspaper arranged in the pocket. Such feeding mechanisms typically employ a sheet-separating device for separating a sheet or other single flat product from a pile of flat products which is arranged in each hopper. The single flat products are drawn from the pile at its bottom end.




A sheet-separating device of this kind is known, for example, from U.S. Pat. No. 3,988,016. That document discloses a high-speed paper inserting apparatus for insertion of supplements into newspapers. The inserts are placed to form a stack and a vacuum gripping member grips the lowermost insert from the stack and carries it to a pair of nip rollers which transport the insert to an opened newspaper. A single sheet requires a different sucker stroke than a 120 page or pre-inserted section. The different sucker motion requirements are due to the way the sheets or sections have to be positioned and controlled for proper singulation. Generally, the bottom of the stack of heavy sections is elevated to eliminate followers. This is accomplished by repositioning the lift hook and restrictors. When these adjustments are made the vacuum cup motion must be changed. To raise the sucker motion so that it properly engages the pile requires the sucker bar to stroke through a greater angle. The sucker adjustment is very critical. It is desirable to make fine adjustments on the fly. The “on the fly” adjustment also facilitates faster initial set-up. It is therefore necessary that the maximum upward position of the sucker cup for each type of section at any time during a production run. Overdriving the sucker into single sheets and light sections will cause bouncing of the pile and evasive feeding/singulation.




To eliminate these problems, some efforts have previously been made to design a lifting sucker and a lifting sucker drive having means for adjusting the maximum position of the sucker cup. German patent DE 976 134 discloses a suction device having a lifting sucker and a lifting sucker drive. As the sucker separates the individual signatures from the top of a pile of signatures, the maximum lower position of the lifting sucker is adjusted by the drive including adjusting means. This is achieved by changing the angular position of two lever arms which are coupled to each other by a cam lever.




SUMMARY OF THE INVENTION




It is an object of the present invention to improve the sucker position of the sheet-separating device. It is further an object to improve the sealing effect of vacuum applied to the lowermost product of a pile of products to be fed from the pile, especially to the grippers of a gripper drum which takes over the flat products for further movement.




Briefly summarized, according to one aspect of the present invention an improved apparatus for separating flat product from a pile of flat products is suggested. The apparatus comprises a sucker mechanism having an upper and a lower part and a central lever with an axis extending through said lever, said axis being movable along said central lever. The central lever is rotatable about the axis and has a first and a second end and a first link located on the first end and a second link located on the second end, the upper part of the sucker mechanism being coupled to the first link and the lower part being coupled to the second link.




Providing a movable axis which extends through the central lever makes it possible to adjust the maximum upward position of the sucker which is the position that requires adjustment depending on the product to be sucked. As some products require an adjustment of the sucker cups to a higher or lower position to better achieve a vacuum seal, the present invention provides an apparatus which meets this demand easily. Due to the geometry of the design and the individual linkages being coupled to other linkages, the maximum height of the cups is adjustable without influencing the maximum lower position of the cups. It is therefore possible to simply adjust the maximum upper position of the vacuum cups by moving the axle which corresponds to the pivot point of the central lever. Shortening the setup time by an adjustment without tools is a further advantage of the present invention, as well as the chance to adjust the cups “on the fly”.




Other features which are considered as characteristic for the invention are set forth in the appended claims.




Although the invention is illustrated and described herein as embodied in a sheet separating device, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.




The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a schematic perspective view of a first embodiment of a sheet-separating device according to the present invention;





FIG. 2

is a schematic side view of a first embodiment of the sheet separating device according to the present invention;




FIG.


3




a


is a schematic perspective view of an adjustment box,




FIG.


3




b


is a schematic side view of the sheet separating device according to the present invention, having an adjustment box,





FIG. 4

is a schematic perspective view of a further embodiment of a sheet-separating device according to the present invention,





FIG. 5

is a schematic view of the sucker mechanism;





FIG. 6

depicts the adjustment mechanism of the sucker cup.











DESCRIPTION OF THE PREFERRED EMBODIMENTS




Referring to

FIG. 1

a perspective view of a sheet-separating apparatus according to the present invention is shown. A number of sucker arms


12


are coupled to a supporting shaft


10


. On each of the sucker arms


12


a sucker cup


14


is mounted, the mounting position of each of the sucker cups


14


being adaptable individually and independently from each other. The supporting shaft


10


is connected to an upper link lever


18


by an upper lever


16


. The components mentioned above form an upper part


22


of the sucker mechanism, where this upper part


22


is coupled to a central lever


26


. The central lever


26


has a first end with a first link joint


28


to which the upper link lever


18


is connected. The separating apparatus furthermore includes a lower part


24


of the sucker mechanism which includes a lower lever


32


, preferably of triangular shape, and a lower link lever


34


which is connected to the lower lever


32


at a link joint


36


. The lower part of the separating apparatus is coupled to the central lever


26


at a second link joint


30


which is provided on a second end of the central lever


26


. A biasing element


38


, which may be a compression spring or a pneumatic actuator, presses the lower part of the separating apparatus


24


against a cam


40


having a cam follower


42


(

FIG. 2

) which is in close contact with the cam. An axis


44


extends through that central lever


26


and may be secured to and released from the central lever by turning a knob


46


.




It is possible to change the position of the axis


44


with respect to the first and second link joint


28


and


30


by moving an adjustment link


48


up and down, i. e. in the direction of the first link joint


28


or the second link joint


30


. The adjustment joint comprises two ends, the first end being secured to the axis


44


and the second end being mounted on a fixed part of the separating apparatus, for example a frame, in a manner, so that the adjustment link


48


is able to rotate about its second end


50


.




Referring to

FIG. 2

, the function of the separating apparatus is shown in more detail. A cam


40


rotates in the direction indicated by the arrow “A”. The cam has a projecting portion


52


. As long as the projecting portion


52


is not in touch with the cam follower


42


, the lower part of the separating apparatus


24


is not deflected and, due to the geometry and the special design of the individual linkages, the sucker cup


14


is in its lower position. Upon further rotation of the cam


40


the projecting portion


52


of the cam


40


contacts the cam follower


42


and initiates the movement of the lower part of the separating apparatus into the direction indicated by the arrow “B”, until it reaches a position indicated by the dotted lines. As a consequence, the central lever


26


rotates and, as the upper part of the separating apparatus is coupled to the central lever, the sucker cup


14


moves into its maximum upper position


54


.




The maximum upper position


54


of the sucker cup depends on the position of the pivot point given by the center of the axis


44


. In order to change this maximum upper position of the sucker, the position of the axis


44


may be changed between an up-position


56


and a down position


58


. An adjustment is accomplished by moving up or down the axis


44


within the limits of the up-position


56


and the down-position


58


. This adjustment may be done by loosening a locking knob


60


and turning an adjustment knob


62


which in turn rotates a spiral-grooved cam


64


that carries the adjustment linkage


48


up and down. After adjustment the locking knob


60


is tightened again.




In a further embodiment of the invention, it is possible to adjust the pivot point on a central lever


26


which is defined by the center of the axis


44


by moving an adjustment box


80


, which is shown in more detail in FIGS.


3




a


and


3




b


. The adjustment box is mounted on a box shaft


86


and comprises fixing means such as fixing screws


82


for fixing the adjustment box in a definite position with respect to the central lever


26


. The adjustment box comprises a center hole


84


where the axis


44


extends through the hole. By loosening the fixing screws


82


it is possible to move the adjustment box


80


up and down along the box shaft


86


and thereby to adjust the axis


44


in a desired position, in order to change the pivot point of the central lever


26


.




In a further embodiment, shown in

FIG. 4

, the adjustment of the pivot point of the center lever


26


is achieved by rotating an angle having a first


89


and second


87


lever around a shaft


90


extending through a hole being arranged in the corner of the angle lever


88


. Preferably, the angle lever


88


is rotated about the shaft


90


by pressing the first leg


89


of the lever


88


in the direction of the axis


44


which in turn causes the axis


44


to move upwardly. Accordingly the axis


44


moves downwardly when the first leg


89


of the angle lever


88


is drawn in a direction away from the axis


44


. Although, the first leg of the lever


88


can be moved in a direction to and away from the axis


44


by any suitable means, the movement preferably is done by a spring adjustment device


92


. The spring adjustment device


92


comprises a rod


96


, extending through the hole of the spring


94


and an adjustment knob


92


.




By turning the knob


92


, an adjustment screw located inside the box


93


is rotated and moves the rod


96


into the direction of the axis


44


, indicated by the arrow D. This movement in turn compresses the spring


94


which is clamped between a screw


95


and the first leg


89


of the angle lever


88


. This increases the pressure of the spring


94


against the first leg of the lever


89


and, as a consequence, causes the angle lever


88


to rotate about the shaft


90


and to move the axis


44


upwardly. By turning the knob


92


in the opposite direction, the spring


94


decreases in compression, the angle lever


88


rotates around the shaft


90


in the opposite direction and, as a consequence, the axis


44


moves downwardly again.




In a further embodiment of the invention, the position of the sucker cups


14


may be changeable with respect to the sucker arm


12


, which is schematically shown in FIG.


5


. Depending on the folded edge and the kind of the flat product to be fed from the pile of flat products, the sucker cups


14


may be adjusted with respect to the position of the sucker arm


12


. This adjustment is necessary, as a thin product has a sharp fold whereas a thick product has a more round and more soft fold, which determines whether the cups need to touch the products in different places. This place may be a different one for every sucker cup of the separating apparatus. It is therefore advantageous to provide means for changing the relative position of the sucker cup to the sucker arm, so that the position of the center of the sucker cup


70


may be changed between an outer position


66


and an inner position


68


.




As shown in greater detail in

FIG. 6

, this adjustment can be done by an adjustment screw


72


which changes the position of the sucker cup


14


upon turning between the outer position


66


and the inner position


68


. Therefore, the position of each individual sucker cup


14


can be changed with respect to the folded edge of a product


74


. As a consequence, it is possible to move the sucker cup


14


closer to the folded edge of the product


74


when the product is thin, and to change the position of the sucker cup


14


away from the folded edge of the product


74


, i. e. from its folded edge, so that the cup would not role around the folded edge and thereby break the vacuum seal. With this individual adjustment even a more irregularly shaped product


74


can be accommodated, when the folded edge of the product is not in the form of the usually sharp straight line.




It will of course be understood that the present invention has been described above only by way of example and that modifications of details can be made within the scope of the invention.



Claims
  • 1. Apparatus for separating a flat product from a pile of flat products, the apparatus comprising a sucker mechanism including an upper and a lower part, a central lever and an axis extending through said central lever and being movable along said central lever, said central lever being rotatable about said axis and having a first and second end and a first link joint located on said first end and a second link joint located on said second end, said upper part of said sucker mechanism being coupled to said first link joint and said lower part of said sucker mechanism being coupled to said second link joint.
  • 2. The apparatus according to claim 1, wherein said upper part of said sucker mechanism comprises a supporting shaft and a plurality of sucker arms and sucker cups, one plurality of said sucker cups being mounted at a predetermined position on one of said sucker arms and each of said sucker arms being coupled to said supporting shaft.
  • 3. Apparatus according to claim 2, wherein each of said sucker arms comprises adjustment means for adjusting said predetermined position of said sucker cups.
  • 4. The apparatus according to claim 1, which further comprises means for fixing said axis in a plurality of fixed positions along said central lever.
  • 5. The apparatus according to claim 4, which further comprises an adjustment link for moving said axis to one of said plurality of fixed positions.
  • 6. The apparatus according to claim 5, which further comprises a spiral-grooved cam and an adjustment knob for rotating said spiral-grooved cam, wherein said adjustment link is in close contact with said spiral-grooved cam for moving the adjustment link into different adjustment positions.
  • 7. The apparatus according to claim 4, which further comprises an adjustment box having a center hole and fixing screws for adjusting the position of the box relative to said central lever.
  • 8. The apparatus according to claim 5, wherein said adjustment link is an angle lever, being formed with a hole in the corner of the lever legs and a shaft extending through said hole, wherein said angle lever is rotatable about said shaft extending through said hole.
  • 9. The apparatus according to claim 8, said apparatus further comprising adjustment means for rotating said angle lever around said shaft extending through said hole formed in said angle lever.
  • 10. The apparatus according to claim 9, wherein said adjustment means is a spring adjustment device comprising a spring, a rod extending through said spring, and a second adjustment knob for moving said rod relative to said angle lever and thereby changing a state of compression of said spring.
US Referenced Citations (9)
Number Name Date Kind
3695606 Wirz Oct 1972
3980293 Shelmire Sep 1976
3988016 Merker et al. Oct 1976
4148473 Johnson Apr 1979
4358101 Janecek et al. Nov 1982
5284334 Yamamoto Feb 1994
5308055 Binnen May 1994
5738347 Tognino Apr 1998
5895037 Baureis et al. Apr 1999
Foreign Referenced Citations (1)
Number Date Country
976134 Mar 1963 DE