Abstract:
An apparatus for lifting a pile of flat products especially a pile of sheets or signatures has a lift lever and a cam follower arm with a first and second end. The cam follower arm is coupled to said lift lever. A cam follower is connected to said cam follower arm and a drive link is coupled to one of said ends of said cam follower arm. A drive link roller is connected to said drive link and a guide ramp is arranged for guiding said drive link roller.

Description:
TECHNICAL FIELD 
     This invention relates to an apparatus for lifting a pile of flat products, especially a pile of sheets or signatures. 
     BACKGROUND OF THE INVENTION 
     In the technology of building books including booklets, magazines, newspapers, periodicals, and so on, he use of collating systems is well known. These 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. The transporting devices may be of any kind, such as flat-backs, saddle conveyors or pocket feeders. Pocket feeders typically comprise a plurality of pockets in which the book block is build up or to which additional sheets or signatures, so-called inserts may be added typically a number of hoppers is arranged along the transporting device where each of the hoppers comprises a feeding mechanism for feeding an individual flat product from a pile of signatures onto the transporting device, in order to progressively 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. As the individual sheets or signatures are fed from the bottom of the pile it is necessary to provide an apparatus to maintain the lowermost flat product in the pile where this apparatus is able to lift the pile during the feeding operation. 
     A lifting apparatus of this kind is already known in the art and described in connection with FIG.  4 . The lifting apparatus  10  according to the prior art can be spilt into three sections: a pivoting shaft  12 , an adjustment link  14  and a pile lifting finger  16  movable along a roller  16 ′, and having an arm  19 ′ with a slot that cooperates with a roller attached with an arm  19 ″. The adjustment link  14  is clamped to the pivoting shaft  12  as well as a cam follower arm (not shown). The can follower arm is connected to a cam on a main hopper drive shaft and actuates the cam follower arm. When the arm pivots it rotates the pivoting shaft  12  and the adjustment link  14  respectively. A roller  18  which is mounted on the adjustment link  14  pushes up and guides down the lifting finger  16 . The pile lifting finger  16  therefore is movable along a path indicated by the arrow between positions “A” and “B”. The lifting height of the pile lifting finger  16  can be adjusted by rotating the knob  15  which in turn rotates the adjustment screw  19 . A locking knob  17  is used to fix this position. 
     It is obvious that the present design does not allow to adjust the height during operation as the adjustment mechanism itself moves up and down during operation. Furthermore, it is also necessary to provide a separate guard around the adjustment as the adjustment moves during operation. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to overcome the shortcomings of the prior art and to provide a lifting apparatus for lifting a pile of flat products, especially a pile of sheets or signatures in a hopper unit, where the adjustment mechanism does not move together with a movement of the pile lifting finger. 
     It is a further object of the present invention to provide a lifting apparatus where the amount of lift can be adjusted to higher and lower position during the operation of the lifting finger (“on the fly”), preferably without the use of any tools. 
     Now, in order to implement these and still further objects of the invention which will become more apparent as the description proceeds, the apparatus of the present development is manifested by the features that it includes a lift lever, a cam follower arm having a first and second end and being coupled to said lift lever at its first end. Furthermore, a cam follower is connected to the cam follower arm and a drive link is coupled to the second end of the cam follower arm. A drive link roller is connected to the drive link and a guide ramp is provided for guiding said drive lint roller. 
     By virtue of this arrangement significantly low mass has to be moved during operation of the apparatus. Furthermore, it is possible to adjust the amount of lift without defecting the downward position which results in less impact of the systems components against other hopper components. This again results in less noise and less wear. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These other objects, advantages and features of the invention will become more apparent from the following description taken in conjunction with the accompany drawings, wherein: 
     FIG. 1 is a perspective view of pile lift according to the present invention; 
     FIG. 2 is a schematic side view of the pile lift in a no-lift position; 
     FIG. 3 is a schematic side view of the pile lift in a lift position; 
     FIG. 4 is a schematic side view of a pile lift according to prior art. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1 a perspective view of the lifting apparatus according to the present invention is shown. The lifting apparatus  20  which may be arranged in a housing  21 , includes a lift lever  22  which is rotatably mounted on an axis  30 . A cam  26  operates on a can follower  28  (FIGS. 2 and 3) which is mounted on a cam follower arm  24 . A first end of the cam follower arm is connected to an axis  32  and a second end of the cam follower arm is coupled to the first end of a drive link  34 , At the second end of the drive link  34  at least one drive link roller  36  is mounted. Preferably, there are three drive link rollers  36 , where one of them is arranged between the two others and the two outer rollers ride upon a guide ramp  38 . The guide ramp is rotatably mounted on the housing  21  and may rotate about pivoting point  40  which may be represented by a rivet pin or a screw  42 . 
     As the guide ramp  38  is rotatable about pivot point  40 . The angular position of the guide ramp  38  may be adjusted to a required value. 
     Referring now to FIG. 2 which shows a schematic side view of the lifting apparatus according to the present invention the guide ramp  38  has been set to a zero angle position which results in a so-called “no lift operation” during the feeding operation of the hopper. As the lifting apparatus is a cam driven device the cam follower arm  24  has a cam follower  28  which is In contact to a cam  26 . The cam follower arm  24  is coupled to the lift lever  22  at a first end of the lift lever  22 . The cam has an irregularly shaped surface resulting in a plurality of cam portions. Preferably, the cam has four portions, a low dwell, a rise, a high dwell and a fall. During the low dwell the system is at an initial rest position. Upon the rotation of the cam  26  the cam follower  28  follows the irregularly shaped surface of the cam  26  and the cam follower arm  24  is rotated about the axis  32 . When the cam follower arm  24  rotates it moves the drive link  34  and the drive link rollers  36  which are arranged at the end of the drive link  34  move along the guide ramp  38 . Depending on the angular position of the guide ramp the lifting lever will only move a certain amount when the guide ramp is different from a so-called “zero position” where the surface of the guide ramp  38  is parallel to the riding surface  44  of the lift lever  22 . In this zero position, which is shown in FIG. 2, the lifting lever will not rise because the roller  36  does not push up the riding surface  44 . 
     However, it is possible to change the angular position of the guide ramp  38  as the guide ramp is rotatably mounted about a pivot point  40 . This is preferably achieved by connecting the guide ramp to a pair of bushings  38 ′, each having a recess  38 ″ for fixing the guide ramp to the bushings and the housing  21  by a screw  42  or a rivet pin. To adjust the angular position of the guide ramp  38  an adjusting unit may be provided for adjusting the amount of rotation of said guide ramp  38  which is shown in FIG.  3 . This adjustment unit includes an adjustment knob  46 , an adjustment rod  48  and a link joint  50  to which the guiding ramp  38  is coupled. By turning the knob  46  which in turn pulls the rod  48  a pivoting of the guide ramp  38  is caused around pivot point  40 . In this way the guide ramp can be adjusted to substantially any desired angular position. When the guide ramp  38  is adjusted to an angular position different from the zero position the space between the guiding ramp  38  and the riding surface  44  is decreased so that whenever the rollers  36  move forward to a position  36 ′ indicated by the dotted lines the lift lever  22  moves from his lower position A to his upper position B without moving the adjustment unit. 
     Preferably, the pivot point  40  of the ramp  38  coincides with the center of the roller  36  in the back position of the roller, which is also the no lift position of the lift lever  22 . Any change in the angular position of the guide ramp  38  therefore requires that the guide ramp  38  is rotated about the center of the roller  36 . This results in no change of the downward position of the lift lever. 
     The degree of rotation of the guide ramp  38  determines the amount of lifting of the lift lever  22  depending on the movement of the drive link  34  and the drive link roller  36  respectively. 
     As already indicated in FIG. 1 the drive link  34  is preferably connected to a plurality of drive link rollers  36 , for example to three drive link rollers, where all the drive link rollers are arranged co-axial. As these drive link rollers are arranged side by side the outer two rollers ride upon the guide ramp which has previously been pivoted to the desired angular position onto bushings situated in the housing  21  of the lifting apparatus  20 . The middle roller pushes the lift lever  22  with respect to the angle of the guide ramp by pushing the riding surface  44 . 
     The lifting apparatus  20  described above allows adjustment without using any additional tools which decreases the amount of setup time. The angular position of the ramp and the amount of lifting of the lift lever  22  respectively can be adjusted during operation of the lifting apparatus as the adjusting unit does not move during operation. Furthermore, the ability to adjust the amount of lift without defecting the downward position results in a less impact of the system components against other hopper components. 
     It will of course be understood that the present invention has been described above purely by way of example and that modifications of detail can be made within the scope of the invention 
     Without further analysis the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapted for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore such adaptations should and are intended to be comprehended within to be comprehend within the meaning and range of equivalence of the following claims. 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 PART LIST 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 10 
                 lifting apparatus (prior art) 
               
               
                   
                 12 
                 pivoting shaft 
               
               
                   
                 14 
                 adjustment link 
               
               
                   
                 15 
                 adjustment knob 
               
               
                   
                 16 
                 pile lifting finger 
               
               
                   
                 17 
                 locking knob 
               
               
                   
                 18 
                 roller 
               
               
                   
                 19 
                 adjustment screw 
               
               
                   
                 20 
                 lifting apparatus 
               
               
                   
                 21 
                 housing 
               
               
                   
                 22 
                 lift lever 
               
               
                   
                 24 
                 cam follower arm 
               
               
                   
                 26 
                 cam 
               
               
                   
                 28 
                 cam follower 
               
               
                   
                 30 
                 axis 
               
               
                   
                 32 
                 axis 
               
               
                   
                 34 
                 drive link 
               
               
                   
                 36 
                 drive link roller 
               
               
                   
                 38 
                 guide ramp 
               
               
                   
                 40 
                 pivot point 
               
               
                   
                 42 
                 screw 
               
               
                   
                 44 
                 riding surface 
               
               
                   
                 46 
                 adjustment knob 
               
               
                   
                 48 
                 adjustment rod