Abstract:
A feeder for collecting printed sheets in an astride position includes a pulling-off drum which has at the circumference thereof gripping members for pulling off printed sheets stacked in a magazine. The feeder further includes a unit for conveying the printed sheets with an open side facing forward into an opening device. The opening device is arranged in front of a collecting device. The unit arranged between the pulling-off drum and the opening device is formed by a pocket wheel or a pocket chain provided with revolving pockets for receiving the printed sheets which are supplied with their folds facing forwardly, and a conveying member arranged in front of the pockets.

Description:
This application is a continuation application of U.S. patent application Ser. No. 09/465,953, filed Dec. 17, 1999, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a feeder for collecting printed sheets in an astride position. The feeder includes a pulling-off drum which has at the circumference thereof gripping means for pulling off printed sheets stacked in a magazine. The feeder further includes means for conveying the printed sheets with an open side facing forward into an opening device. The opening device is arranged in front of a collecting device. 
     2. Description of the Related Art 
     Feeders of the above-described type have a pulling-off drum which has at the circumference thereof gripping members which serve to pull the individual sheets from a stack and to convey the sheets to opening drums. The pulling-off drum grasps the sheets at their closed backs and conveys the sheets to a stationary pocket arranged at the circumference of the drum, wherein the sheets come to rest against a stop in the pocket. Additional gripping means are provided for grasping the sheets at their open ends and for pulling the sheets against the direction of rotation of the drum out of the pocket and to convey the sheets to the opening drums where they are opened and placed on the collector chain. 
     In the feeder of this type, a precise contact or impact of the sheets at the stationary stops of the pocket is no longer ensured at very high speeds because the sheets can no longer come to rest in the pocket. When the sheets are not precisely placed in the pocket, they cannot be exactly grasped with the additional gripping means at the open ends and can subsequently not be safely opened in the opening drums. This means that a further increase of the output is not possible. 
     SUMMARY OF THE INVENTION 
     Therefore, it is the primary object of the present invention to provide a feeder of the above-described type which ensures a high output and which can still be manufactured inexpensively and operates safely. 
     In accordance with the present invention, the means arranged between the pulling-off drum and the opening device is formed by a pocket wheel or a pocket chain provided with revolving pockets for receiving the printed sheets which are supplied with their folds facing forwardly, and a conveying member arranged in front of the pockets. 
     As a result of the configuration according to the present invention, the use of several pockets makes it possible that the sheets can remain in the pockets for a much longer time. Consequently, there is enough time for the sheets to come to rest in the pockets and, if necessary, for the sheets to be precisely aligned. Thus, the sheets which have come to rest in the pockets can be conveyed precisely to the opening drums even at higher processing speeds. 
     Another advantage of the feeder according to the present invention is seen in the fact that sheets can be supplied with several pulling-off drums. In that case, one of the pulling-off drums can be used, for example, as a repair element or in a 2:1 operation for facilitating the manual feeding by several persons. Also possible is a selective production in which different sheets are conveyed in a controlled manner from several stacks. In addition, one of the pulling-off drums can be used for automatic feeding and another pulling-off drum can be used for a manual reinsertion of the sheets. 
     The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     In the drawing: 
     FIG. 1 is a schematic elevational view of a feeder according to the invention; 
     FIG. 2 is a schematic partial view of a pocket with a sheet placed in the pocket; 
     FIG. 3 is a partial sectional view showing the insertion of a sheet into a pocket; 
     FIG. 4 is a schematic elevational view of another embodiment of the feeder according to the invention; and 
     FIG. 5 is a schematic elevational view of yet another embodiment of the feeder according to the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The feeder  60  illustrated in FIG. 1 includes a machine frame  11  with two support plates  12 . Mounted on the support plates  12  are a pulling-off drum  1 , a pocket wheel  15  and two opening drums  9  and  10 . A stack  3  with printed sheets  2  is located above the pulling-off drum  1 . The printed sheets  2  are individually pulled off by means of the pulling-off drum  1  at the bottom side of the stack  3 . The sheets  2  preferably are sheets which, as shown in FIG. 2, have a fold  6  at one end and a gripping edge  33  at the opposite open end  8 . The sheets  2  of the stack  3  are placed by means of the feeder  60  individually on a conventional collector chain  48  or a collector saddle and are conveyed to additional processing units, for example, a stitching machine, not shown. 
     The pulling-off drum  1  is composed of a drum  16  with a shaft  17 , wherein the drum  16  has at the circumference thereof gripping means  100  for grasping each sheet  2  of the stack  3  in the vicinity of the fold  6  of the sheet  2 . These gripping means are, for example, suction devices and gripping devices. 
     The drum  16  rotates in the direction of the arrow  18  and the sheets  2  grasped by the gripping means are conveyed between belts  36  and  22  at first essentially vertically downwardly and then around a roller  25  essentially horizontally towards the pocket wheel  15 . After the transfer of the sheets into the belts, the gripping means once again release each sheet  2 . As shown in FIG. 1, the belt  36  is placed around the drum  6  as well as around two guide rollers  19  and  21 . The endless belt  36  may be composed of several laterally offset partial belts. The belt  22  is placed around two rollers  24  and  25  which are mounted on a vertical support member  23 . The belt  22  may also be composed of laterally offset partial belts. Hinged to the lower end of the support member  23  is a guide roller  26  which cooperates with the guide roller  21  for guiding the sheets  2 . The sheets  2  are placed between these two drums  21  and  26  in FIG. 1 with the fold  6  facing forwardly approximately horizontally into an open pocket  5 ′ of the pocket wheel  15 , as schematically shown in FIG.  3 . 
     The pocket wheel  15  has a plurality of radially extending pockets  5  which are attached to a hub  34 . However, the radial direction of the pockets  5  is not absolutely required. Also conceivable is an embodiment in which the pockets  5  form an angle with the radial direction. As can be seen in FIG. 3, the pockets  5  preferably include a rear portion  27  rigidly connected to the hub  34  and a pivotable front portion  28 . For example, as illustrated in FIG. 3, the front portion  28  can be connected to the hub  34  through a hinge  32  and can be pivoted in the directions of the double arrow  52  by means of a control cam, not shown. 
     In the position illustrated in FIG. 3, the front portion  28  is pivoted away from the rear portion  27  in such a way that the pocket  5 ′ has a front opening  35  through which the sheets  2  can be inserted in the direction of the arrow  53  against a stop  30 . The stop  30  is preferably radially adjustable for adjusting the pocket to different sizes of the sheets. When the sheet  2  is inserted, it impinges with the fold  6  against the stop  30 . Located opposite the stop  30  at the radially outer end of the rear portion  27  is an upwardly protruding part  27   a  which supports the sheet  2  at the open end  8  as seen in FIG.  2 . As illustrated in FIG. 2, the rear portion  27  is formed by several radially extending arms  54 . Of course, it would also be possible to construct the rear portion  27  flat and the corresponding front portion  8  with a part  27   a  protruding beyond the end edge of the rear portion  27  which, when the pocket  5  is closed, prevents the sheet  2  from escaping out of the pocket  5 . 
     As illustrated in FIG. 2, for laterally aligning the sheets  2 , a guide member  31  is arranged laterally for precisely aligning the sheets  2  when they are inserted. The guide member  32  may be stationary or forwardly and backwardly oscillating. Two such guide members  31  can also be arranged at opposite sides. Also in this case, the guide members  31  are preferably adjustable for adjusting to different sheet sizes. Preferably, all pockets  5  are constructed equally. 
     As illustrated in FIG. 1, the pocket wheel  15  is driven in the clockwise direction. In all pockets  5  the front portion  28  is controlled in such a way that, after the sheet  2  has been inserted, the front portion  28  is pivoted towards the rear portion  27  and the pocket  5  is closed in this manner. As a result, the inserted sheet  2  is precisely positioned and held in the pocket  5  and can come to rest as the pocket wheel  15  continues to rotate in the clockwise direction. It is essential that the sheet  2  is securely guided and supported after being pulled off from the stack  3  until being placed in the pocket  5 ′. 
     The inserted sheets  2  are individually removed from the pockets  5  approximately in the 8 o&#39;clock position of the pocket wheel by means of an opening drum  10 . The dwell time of the sheets  2  between the insertion and the removal is a multiple of the feeding cycle. Consequently, the dwell time is relatively long and certainly sufficiently long for allowing the sheets  2  to come to rest. For removing the sheets  2 , the pockets  5  are opened in the area of the opening drums  9  and  10  by pivoting the respective front portion  28  away from the rear portion  27 . The sheets  2  are grasped by means of a radially extending shoulder  7  of the opening wheel  10 . The sheet  2  is grasped at the gripping edge  33  thereof in the conventional manner, for example, by means of schematically indicated suction devices  55  or grippers, and are guided between the two opening drums  9  and  10 . The sheets  2  are guided by a guide member  55  arranged above the opening drum  10 . The two opening drums  9  and  10  open the grasped sheet  2  and place it in the conventional manner on the collector chain  48 . 
     The feeder  70  illustrated in FIG. 4 also includes a pocket wheel  15  which is driven in the direction of the arrow  45  in the clockwise direction. However, feeding of the pockets  5  takes place in this case with a pulling-off drum  20  in an upwardly inclined direction. The pulling-off drum  20  removes the sheets  2  also from a stack  3  which is arranged above the drum  16 . The sheets  2  pulled off from the stack  3  are guided at the circumference of the drum  16  by a belt  36  which is placed around a drive roller  37 , a guide roller  38  and a pressure roller  39 . The belt  36  can also be composed of partial belts. Arranged above the roller  39  is an additional belt  57  which is placed around a drive roller  56  and about a guide roller  41 . The sheets  2  travel on the belt  36  between the roller  39  and the belt  57  and are inserted into a pocket  5 ′ with the fold  6  facing forwardly. At least one arm  42  protruding into the pocket wheel  15  forms an upper stop for the sheets  2  in the pocket  5 ′. This arm  42  is pivotable about a hinge  43  in the directions of the arrow  44 . This pivoting makes it possible to adjust the stop in an infinitely variable manner to adjust to different sheet sizes. Also provided may be lateral parts  31  which laterally center the sheets  2  when they are inserted into the pocket  5 ′. As illustrated in FIG. 4, when the sheet  2  is inserted into the pocket  5 ′, the pocket  5 ′ is inclined downwardly. For example, the angle  57  relative to the horizontal is about 40°. 
     When the pocket wheel rotates further, the front portion  28  is pivoted as explained above and the pocket  5 ′ is closed as a result. Approximately when reaching the 8 o&#39;clock position, the pocket  5 ′ is once again opened and, as explained above, the sheet  2  is removed by means of the two opening drums  9  and  10  from the pocket  5 ′, is opened and placed on the collector chain  48 . 
     In the feeders  60  and  70 , the sheets  2  are removed from a single stack  3  and supplied to the pockets  5 . However, more than two stacks  3  can be provided at the circumference of the pocket wheel  15  and the corresponding number of pulling-off drums  1  or  20  may be provided. The stacks  3  may contain sheets  2  of equal or unequal sizes. Also conceivable is an embodiment in which one of the pulling-off drums  1  or  20  is used for a manual reinsertion or feeding of sheets. One of the pulling-off drums may also be used as a repair element. Moreover, when several pulling-off drums are provided, manual feeding by several persons is made possible. 
     FIG. 5 of the drawing shows a feeder  80  which has a pocket chain  50  instead of a pocket wheel  15 . This endless pocket chain  50  is placed around a drive wheel  51  and a guide wheel  50 . The pocket chain  50  has at regular intervals pockets  5  which are constructed as explained above and to which the sheets are fed obliquely from above by means of pulling-off drums  1  and  1 ′. Feeding is carried out as described above in connection with FIG.  3 . The removal of the sheets  2  also takes place as described above by means of opening drums  9  and  10 . It is also essential in this feeder  80  that the dwell time of the sheets  2  in the pockets  5  is a multiple of the feeding cycle and, thus, the sheets  2  can be aligned if necessary in a precise position and sufficient time remains for allowing the sheets to come to rest. Even at high processing speeds, it is possible in this feeder to convey the sheets  2  which have been positioned and come to rest in the pockets  5  to the opening drums  9  and  10  and to open the sheets  2 . 
     The invention is not limited by the embodiments described above which are presented as examples only but can be modified in various ways within the scope of protection defined by the appended patent claims.