Abstract:
A device for stacking and destacking a stream of imbricated, substantially planar, flexible units to form or destack a layered stack. The device is a stacker, adapted to receive a stream of units from a source thereof, and a plurality of transfer sheets. The feeder delivers the stream of units to the stacker. 
     The stacker has staging belts which receive portions of the stream and deposit the units serially on one of the transfer sheets, as it is withdrawn from the sheet stack. This forms an imbricated layer of the units and the transfer sheet. The stacker deposits the imbricated layer on a removable support and repeats the cycle to deposit successive imbricated layers on the preceding layers. Destacking is carried out by simply reversing the process.

Description:
This application is a continuation-in-part of U.S. application Ser. No. 07/850,414, filed Mar. 12, 1992, now abandoned. 
    
    
     The present invention is directed to a device and method for storage and retrieval of flat, planar, usually flexible articles. The invention will be discussed and described in connection with the handling of printed material, such as newspapers, but this is by way of convenience only and is not intended to limit the application of the invention. 
     BACKGROUND OF THE INVENTION 
     Newspapers, both daily and particularly Sunday editions, are made up of an outer section or jacket and one or more inserts of various kinds. These inserts consist of additional sections, advertising brochures, leaflets, and the like. Since the jacket usually contains the latest news, it is, of necessity, printed last. The inserts, not being so time sensitive, are prepared in advance and stored until needed. 
     Therefore, it is desirable to be able to take the various inserts from their sources (usually printing presses), store them for a period of time until the jackets are ready, retrieve them, and insert them into the jackets. Furthermore, it is particularly advantageous if the inserts can be maintained in imbricated form during all of the foregoing operations. Thus, there is a need for a device which will take the inserts from the presses, imbricate them, store and retrieve them in imbricated form, and deliver them to the next processing device, usually an inserter. Moreover, the system should be mobile so that the inserter can be in one building and the inserts stored in another. The present invention is intended to provide such a device. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The present invention is directed to a device and method for forming a stack made up of layers of imbricated, substantially planar, flexible units. The device and method are also capable of retrieving (destacking) the imbricated layers from the completed stack. 
     In essence, the invention comprises a source of a continuous stream of the aforementioned units, a storage and retrieval unit, which receives the stream and, as transfer sheets are withdrawn from a stack thereof, deposits the copies thereon as an imbricated layer. The layer is placed on a support and successive layers, as formed, are deposited in a similar manner on the preceding layers. 
     Advantageously, a pallet of standard width is provided as the support. Thus, when the stack is complete, it can be removed from the device by means of a pallet jack and/or a fork lift truck. If rollers are provided beneath the pallet, it can be easily rolled out of the device manually, if desired. 
     In a particularly desirable modification of the device, the functions of the stager and pallet storage are combined in one section. The advantage of this embodiment resides in the reduced amount of floor space which is required by the device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings, constituting a part hereof, and in which like reference characters indicate like parts, 
     FIG. 1 is a perspective schematic view of the storage and retrieval device, with some parts omitted for clarity. 
     FIG. 2 is a schematic view of the releases, lay down belt, fold pressers, and diverter belt; 
     FIG. 3 is a schematic cross-section along the line 3--3 of FIG. 2, also showing the transfer sheet storage and stager; 
     FIG. 4 is a schematic perspective view, with parts omitted for clarity, showing the formation of the imbricated layers and stack; 
     FIG. 5 is a schematic elevation, with parts omitted for clarity, of the staging, stacking, and pallet supply storage; 
     FIG. 6 is a plan view of the device as shown in FIG. 5; 
     FIG. 7 is a plan view of a transfer sheet; 
     FIG. 8 is a view similar to that of FIG. 4 showing retrieval of the copies from the stack; 
     FIG. 9 is a view, similar to that of FIG. 1, showing the copies being retrieved and carried forward to the inserter; 
     FIG. 10 is a side elevation of a preferred embodiment of the present invention, and 
     FIG. 11 is a view similar to that of FIG. 1 showing the counters and control. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring more specifically to FIG. 1, storage and retrieval device 1 comprises gripper conveyor 2, shingle diverter 3, transfer sheet storage and stager 4, stack formation section 5, and pallet storage 6. The next handling step is illustrated as inserter 7, but this device forms no part of the present invention. It can be replaced by any desired handling step or device. 
     The feed mechanism is shown more specifically in FIGS. 2 and 3. Gripper conveyor 2 is provided with releases 10, one of which is over each lay down belt 8. Releases 10 open the appropriate grippers (not shown) and deposit the copies onto the respective lay down belts 8. The folded edges of the copies are transverse to the direction of movement of belts 8. Since air is often contained in the copies, it is preferably removed by passing them through fold presser 11, which comprises pairs 12 of rollers, there being one pair for each belt 8. 
     The present invention is fully operable if the newspaper copies are fed to the shingle diverter and/or stager with their folded edges transverse to the direction of movement of the belts carrying them. However, if this is done, since the folded edges are the longer dimension, the rows of copies will end up being spaced further apart than a standard pallet width. Therefore, it is particularly advantageous for lay down belts 8 to deposit the copies on diverter belts 9, which are at right angles thereto. As a result, the copies are thus positioned with their folded edges parallel to the direction of movement of diverter belts 9 and staging belts 14. 
     A further advantage resides in the fact that lay down belts 8 and diverter belts 9 can be separately controlled so that their respective speeds are independent of each other. By suitable adjustment of the relative speeds, the degree of imbrication of the copies can be controlled. Thus, if diverter belts 9 are speeded up relative to feed belts 8, the amount of imbrication will decrease. On the other hand, if diverter belts 9 are slowed relative to feed belts 8, the degree of imbrication will be increased and the leading edges of adjacent copies will be located closer to one another. Since it is desired to maintain an approximately equal thickness of the layers (suitably about 21/2 inches), thicker copies require less imbrication than thinner copies. The foregoing mechanism provides a means for making any necessary or desirable adjustments with respect thereto. 
     Copies 18 then proceed in the direction of arrows 13 (see FIG. 3) and are deposited on adjustable portions 49 of staging belts 14 by diverter belts 9. The copies are then carried to horizontal portions 48 of belts 14 which are located in frame 44. Stack 16 of the transfer sheets is beneath staging belts 14. Top sheet 15 is moved in the direction of arrow 45 and, at the same time, staging belts 14 deposit copies 18 thereon, thus forming an imbricated layer. As each transfer sheet 15 is removed from stack 16, stack 16 is moved in the direction of arrows 17 by approximately the thickness of one sheet 15 so as to maintain the top sheet in the same position relative to staging belts 14. 
     The staging belts and associated elements of the invention are shown in greater detail in FIG. 4. For formation of the storage stack, belts 14 move in the direction of arrow 21. As transfer sheet 15 is withdrawn from stack 16 (to the right as shown in FIG. 4), belts 14 synchronously feed copies 18 thereon, thus forming layers 19 and placing them on top of one another to form layered stack 25. Pallet 20 is located at the bottom of stack 25 and is moved in the direction of arrow 23 as layers 19 are deposited at the top thereof. The movement of pallet 20 is controlled so that the uppermost layer 19 is always at the proper level to receive sheet 15 and copies 18. Analogously, stack 16 is moved in the direction of arrow 22 as each transfer sheet 15 is removed therefrom, thus keeping the top sheet at the appropriate level. 
     Since the present invention is intended to be used in conjunction with a continuous stream of copies, provision must be made for continuing to receive copies, even though the storage and retrieval mechanism has paused to permit a completed stack to be removed and a new pallet introduced. Copies 18 are deposited in a predetermined length on one of the three lay down belts 8. When that one is full, it begins transfer to one of diverter belts 9. This is repeated for second and third feed belts 8 and second and third diverter belts 9. In similar manner, diverter belts 9 transfer copies 18 to staging belts 14. Hence, while staging belts 14 are waiting until all three are filled, there is at least one lay down belt 8 and diverter belt 9 which can receive copies 18 from the continuous stream. Thus, there need be no interruption or spaces between the predetermined copy lengths and the device can receive copies 18 from the continuous stream and form them into desired stacks 25. 
     In FIGS. 5 and 6, the operation of stager 4, stack formation section 5, and pallet storage 6 is shown. Guides 50 receive sliders 33 which are adapted for motion to the left and right as shown in FIG. 6. Shovels 34 are mounted on sliders 33 and are movable toward and away from each other in a direction perpendicular to that of sliders 33. Sliders 33 are shown in their extreme left position in the upper portion of FIG. 6 and in their extreme right position in the lower portion of that figure. However, the pairs of sliders 33, and their attached shovels 34, are intended to move in the same direction and at the same time. 
     When horizontal portions 48 of belts 14 are ready to discharge copies 18 onto the stack being formed in stack formation section 5, both sliders 33 move to the left position, as shown in the upper part of FIG. 6. Shovels 34 then move toward each other so as to slide partially under and hold the top most transfer sheet. This position is shown in the upper portion of FIG. 6 at stager 4. Sliders 33 then move to the right in synchronism with horizontal portion 48 of staging belts 14 (not shown in FIG. 6). This position is shown at the lower half of FIG. 6 at stack formation section 5. The cycle is repeated as needed until the stack is fully formed. Thereafter, the leveler (not shown) lowers stack 25 (see FIG. 5) so that the uppermost layer is beneath the level of shovels 34 and buffer 27. Stack 25 is then removed from the device in a direction transverse to arrows 13 and 29. 
     At this point, sliders 33 are in their right position as shown in the bottom half of FIG. 6. Shovels 34 move toward each other and grip pallet 20 at the top of pallet stack 24. Sliders 33 then move to their left position, carrying pallet 20 to buffer 27 in stack formation section 5. The transfer sheets, with copies 18 synchronously deposited thereon, are moved by sliders 33 and shovels 34 onto buffer 27. Meanwhile, base 51 rises so that it contacts the underside of bottom pallet 20. Thereafter, buffer 27 releases and the stack formation continues until completed. 
     When stack 25 is completed and removed from the device, it can be stored at any desired or convenient location. Since the system is quite mobile, the stacks can even be stored in a building apart from the one in which the device of the present invention is located. 
     When it becomes necessary to retrieve copies 18, stack 25 is returned to area 5. In order to maintain the proper orientation of copies 18, it is necessary to rotate stack 25 180° about its vertical axis. It is then returned to area 5 for retrieval. 
     Referring now to FIG. 8, the first step of retrieval is shown. Staging belts 14 are reversed and transfer sheet 15 forming part of upper layer 19 is moved in the direction of arrow 37. Noses 46 on one end of diverter belts 14 enter between copies 18 and transfer sheets 15. Copies 18 are carried onto horizontal portions 48 of staging belts 14, and transfer sheet 15 is placed on the top of stack 16. The support for stack 16 then moves in the direction of arrow 39 to prepare stack 16 to receive the next transfer sheet 15. At the same time, the support for pallet 20 moves in the direction of arrow 38. Thus, the transfer takes place at the same level at all times. 
     In a preferred form of the invention, transfer sheet 15 is provided with notches 36 at one or both ends thereof (see FIG. 7). Notches 36 correspond and are complementary to noses 46. This assists in the separation of copies 18 from transfer sheet 15. 
     As shown in FIG. 9, staging belts 14 move in the direction of arrow 47 and feed copies 18 onto adjustable portion 49. As can be seen in FIG. 3, adjustable portion 49 move in the direction of arrow 43 to assume retrieval position 42 as shown in phantom. Referring again to FIG. 9, copies 18 are then deposited, one row at a time, onto converter table 40, thereby to form single stream 41 which, in the embodiment shown, passes on to inserter 7. 
     A preferred form of the device is shown diagrammatically in FIG. 10. This is a view substantially comparable to that of FIG. 5. Pallet building section 52 contains pallet 20 and stack 25. However, stager 4 and pallet storage 6 are combined into pallet feed section 53. Section 53 contains upper pallet 56 and lower pallet 57, carrying stacks 54 and 55 of a predetermined number of transfer sheets, respectively. Operation is initiated by inserting pallet 20, carrying a transfer sheet is placed in section 52. It is elevated in the same manner as in the principal form of the device. As new transfer sheets are needed, they are taken from stack 54; this process continues until stack 54 has one transfer sheet left and stack 25 is complete. 
     Stack 25 is then moved out of section 52, preferably in a direction transverse to the direction of flow of the units. At the same time, upper pallet 56, carrying a transfer sheet, is moved from pallet feed section 53 to pallet building section 52 and lower pallet 57, carrying stack 55 of transfer sheets, moves upwardly to an appropriate level so that the uppermost transfer sheet can be taken from stack 55 and fed to pallet building area 52 as stack 25 is built. A new pallet (not shown), also carrying the predetermined number of transfer sheets, is moved into position beneath pallet 55. The cycle is now complete and can be repeated as desired. 
     As a further improvement, there is provided a (as shown in FIG. 11) copy counter 58 which senses the presence or absence of copy 18 in each gripper of conveyor 2. There is also gripper counter 59 which counts the grippers of conveyor 2. In this way, it is possible to determine when and where there are &#34;holes&#34; in the copy stream. Belts 8 and 9 are controlled by control 60 so that, when there is a hole, the belt stops for a suitable length of time to allow the next copy 18 to be properly deposited. 
     While only a limited number of specific embodiments of the present invention have been expressly described, it is, nonetheless, to be broadly construed and not to be limited except by the character of the claims appended hereto.