Abstract:
A method for splitting a product stream comprising the steps of delivering a plurality of products to an circular path, transferring a first product of the plurality of products inwardly from the circular path to a first substream, and transferring a second product of the plurality of products inwardly from the circular path to a second substream. Further provided is a device for splitting a product stream comprising a support rotatable about a central axis, the support having an outer circumference and an inner circumference; and at least one transfer device attached to the support for receiving products of the product stream, the transfer device having a first position for receiving a first product of the products at the outer circumference and a second position for delivering the first product to a substream at the inner circumference.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to printing presses and more particularly to a device and method for splitting a stream of printed products. 
     2. Background Information 
     Web printing presses print a continuous web of material, such as paper. The continuous web then is cut in a cutting unit so as to form book blocks. These book blocks can be sections of a newspaper, for example. In order to process the book blocks, for example to perform a trimming operation, it is often desirable to slow the product stream. This may be accomplished by splitting the product stream and then to decelerating the resultant split product streams. This often requires a large amount of floor space. 
     U.S. Pat. No. 3,702,129 describes a mechanical book clamp which can accommodate various book thicknesses. A chain drive can be used to move the clamps along a desired path. 
     U.S. Pat. No. 5,740,900 discloses an apparatus for splitting a product stream into an A stream and a B stream. The signatures are gripped by grippers, and alternating grippers rotate to split the product stream. This device requires a large amount of floor space to perform the split, and performs only an A/B split. 
     BRIEF SUMMARY OF THE INVENTION 
     An object of the present invention is to provide for a device and method for splitting a printed product stream, such that the amount of floor space required for the split is reduced. An additional or alternative object of the present invention is to be able to split the printed product stream into more than two substreams. 
     The present invention provides a method for splitting a product stream including the steps of delivering a plurality of products to a circular path, transferring a first product of the plurality of products inwardly from the circular path to a first substream, and transferring a second product of the plurality of products inwardly from the circular path to a second substream. 
     By using the circular path and inward transferring, the splitting can be accomplished in a vary small amount of floor space, i.e. with a small footprint. 
     A single transfer device may perform both the transferring of the first product and the transferring of the second product. The method also may further comprise transferring a third product of the plurality of products inwardly from the circular path to a third substream and transferring a fourth product inwardly from the circular path to a fourth substream. The first substream, the second substream, the third substream and the fourth substream then may be located in a circular arrangement ninety degrees apart. In such an arrangement, the first product may be received by a transfer device attached to a support and delivered to the first substream after a ninety degree rotation of the support. The transfer device preferably rotates 180 degrees during the ninety degree rotation of the support. 
     The first and second substreams preferably move downwardly, which permits for a minimum of floor space use. 
     The present invention also provides a device for splitting a product stream comprising a support rotatable about a central axis, the support having an outer circumference and an inner circumference, and at least one transfer device attached to the support for receiving products of the product stream. The transfer device has a first position for receiving a first product of the products at the outer circumference and a second position for delivering the first product to a substream at the inner circumference. 
     The at least one transfer device preferably includes four transfer devices. The support may include a hub and four arms extending from the hub. A first of the at least one transfer device preferably is located at an end of one of the four arms, the end being located away from the hub. The support also may include a hub and eight arms. In the second position the transfer device is capable of receiving a second product of the products at the outer circumference. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Two embodiments of the present invention are described below by reference to the following drawings, in which: 
     FIG. 1 shows a top view of a first embodiment of the present invention; 
     FIG. 2 shows grippers in a chain track; and 
     FIG. 3 shows a view of the product transfer device of the present invention; 
     FIG. 4 shows an alternate construction of the product transfer device; and 
     FIG. 5 shows a top perspective view of a first embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 shows a top view of an embodiment of the present invention. A product stream  1  of individual book blocks  3  enters splitting device  100 . Each of the book blocks  3  is held in an individual gripper device  10 , which is releasably attached on one side to a track  12 . The individual gripper devices  10  can be driven in the track by, for example, transport modules moved by a train drive. The individual gripper devices may be the same as those disclosed in the co-pending U.S. patent application Ser. No. 09/448,990 filed on Nov. 24, 1999. This patent application is incorporated by reference herein. 
     Each of arms  27  of support  20  supports a product transfer device  30 . At the 12:00 location of support  20 , product transfer device  30  grasps a first gripper device  10  on its side opposite track  12  at outer transfer circumference  24 . The gripper device  10  is then released on its track  12  side. As will be described, product transfer device  30  then moves the gripping device  10  inwardly, so that after a ninety degree rotation of the support  20 , i.e. the 9:00 position of support  20 , the gripping device is moved inner circumference  26  at substream A. This process is repeated by transfer device  30  for three more gripping devices during a full rotation of arm  27 . 
     The embodiment shown in FIG. 1 splits product stream  1  into four downwardly moving (i.e. into the page) product streams at locations A, B, C and D. Splitting device  100  operates as follows: 
     Support  20  has a velocity at outer circumference  24  slightly slower to that of the velocity of product stream  1 . The first of a four product set, for example product  1 A of a product set including products  1 A,  1 B,  1 C, and  1 D, thus moves against each product transfer device  30  as the product transfer device  30  rotates to a first transfer location  40  . The next product transfer device  30  as it rotates to transfer location  40  picks up the next A product, shown as  10 A. The products are spaced and the product speed along track  12  and the velocity of support  20  are timed so that four products pass between each two arms of support  20 . 
     At the 10:30 position, product  2 A, which was picked up location  40 , has been rotated inwardly by product transfer device  30 , but has not yet reached inner transfer circumference  26 . Products  2 B,  2 C and  2 D queue behind transfer device  30 , but are not yet attached to the transfer device  30 . 
     At the 9:00 position, product  3 A has been rotated by product transfer device  30  to the inner transfer circumference, at which point the product or gripper is released and the product moves downwardly into substream A. At the same time, product  3 B is accepted by product transfer device  30  at second transfer location  41 , while products  3 C and  3 D remain queued. 
     At the 7:30 position, product  4 B has been moved inwardly by the transfer device  30 , while products  4 C and  4 D queue but are not accepted by the transfer device  30 . 
     At the 6:00 position, product  5 B has been moved to inner transfer circumference  26  and is moved downwardly into product substream B. At this time, product  5 C is attached to transfer device  30 , while product  5 D remains queued. 
     At the 4:30 position, product  6 C has been moved partially inward by product transfer device  30 , while product  6 D queues behind but is not yet attached to product transfer device  30 . 
     At the 3:00 position, product  7 C enters products substream C, while product  7 D is attached to transfer device  30 . 
     At the 1:30 position, product  8 D has been moved partially inwardly by transfer device  30 . 
     At the 12:00 position, product  9 D enters the D substream while product  1 A is being picked up. 
     Thus, each arm of support  20  processes four products during a rotation. For example, arm  27  will process move product  1 A into the A substream at the 9:00 location, product  1 B into the B substream at the 6:00 location, product  1 C into the C substream at the 3:00 location and product  1 D into the D substream at the 12:00 location as it completes a full rotation. Arm  27  will process products  10 A,  10 B,  10 C and  10 D so that they move into substreams A, B, C, and D, respectively. 
     Advantageously, at each substream A, B, C, D drop off location the relative velocity of the products is zero, i.e. the arm  27  is moving in one direction while the transfer device  30  is moving the product in the opposite direction. This zero velocity makes the transfer of the products to the substream, for example, to a belt, gripper system or other moving device simple. 
     Although the embodiment of FIG. 1 has been shown with eight arms, it is possible that four arms, two arms, or even one arm could be used to process the products into a plurality of streams. 
     FIG. 2 shows the track  12  of FIG.  1 . Track  12  has movable clamping elements  60  which are attached by a chain so as to move within the track at spaced intervals. Clamping elements  60  have a spring-activated clamp  62 , which forms jaws to grip gripping device  70 . Gripping device  70  includes a book support  72  which clasps the book block or product. The gripping device  70  has at each side a bar, bar  73  (FIG. 4) and bar  74 . Bar  73  may be releasably gripped by transfer device  30 , for example through jaws  38  in FIG.  3 . 
     FIG. 3 depicts the product transfer device  30 , which includes a belt or chain drive  36  attached to arm  27  of support  20 . Belt or chain drive  36  can be geared to the support  20  so that for each revolution of an arm  27 , the belt or chain drive makes two revolutions. Extending downward from belt drive  36  is a transfer gripper  37  having jaws  38  for grasping bar  74  of a gripping device  70  (FIG.  2 ). Transfer gripper  37  also includes a support arm  39  which holds the jaws so the jaws grasp bar  74  without interfering with a printed product held in a gripping device. Each transfer device actually has two transfer grippers spaced equidistant about the belt of belt drive  36 . 
     After the products are transferred to substreams A, B, C and D (FIG.  1 ), the jaws can release the gripping device  70  and the gripping device can be further carried in a downward direction, for example, by a belt in an indexable manner. 
     FIG. 4 shows an alternate arrangement for transfer device  30 . Transfer device  30  has a clamp  32  which can grasp bar  74  (FIG.  2 ). Although not visible, bar  73  is first gripped by clamp  62  in FIG. 2, and then released as gripping device  70  is rotated by the transfer device  30 . Clamp  32  is supported on a rotatable support  33 , which in turn is supported by a rotatable arm  34 . A support  35  can be attached to support  20 , through for example a plurality of arms. 
     FIG. 5 shows an alternate embodiment of the present invention in which gripping devices are not used. A product stream  101  is delivered for example on a conveyer belt to trays  103 , which rotate on a track  112 . The products are delivered to trays  103  shortly before a 12:00 location  130 . A transfer device  30  which has a gripper on a belt  32  then grips the product at 12:00 location  130  and moves the product to an A substream at the  3 : 00  location  131 . At the same time, the transfer device  30  then picks up the next product and transfers the next product to the B substream at 6:00 location  132 . At location  132 , the next product is picked up of tray  103  by the transfer device  30 , which moves this product inwardly to substream C at the 3:00 location  133 . At the same time as this product is delivered to substream C, the next product is picked up at location  133  by transfer device  30 , and is then moved inwardly to arrive at substream location D when support  120  returns to the 12:00 location  130 . 
     Transport of the products through the substreams and the processing station are further disclosed, for example, in co-pending U.S. patent application Ser. Nos. 09/449,127 and 09/448,986 entitled “High Speed Processing Device for Printed Products” and “Device and Method for Trimming Printed Products” both filed on Nov. 24, 1999. These two applications are also hereby incorporated by reference herein. 
     “Outer circumference” as defined herein need not be the outermost circumference of the support, but is merely a circumference further away from the center axis than the inner circumference.