A METHOD OF TRANSPORTING THIN, PLANAR PRODUCTS, AND A LOAD CARRIER FOR SUCH TRANSPORT

Abstract: A method of transporting stacks of thin, planar products, such as periodicals, books, newspapers or the like, and a load carrier for such transport. The load carrier comprises a bottom (5) and four sides (1 - 4), and at least one pair of of the mutually opposite sides (1, 3 resp. 2, 4) is provided with one or more upwards open slots (6, 7 resp. 8, 9 and 10, 11), whereas the bottom (5) is provided with a corresponding opening pattern in the form of upwards open channels (22, 23) which are open towards said slots. The load carrier is transported on a chain conveyor, and the product stack (18) placed on the carrier pos­ sibly is strapped while resting on the carrier, and the carrier is separa­ ted from the stack (18) by introducing a supporting means in the bottom chan­ nels (22 or 23) of the carrier beneath the stack, whereafter the stack is separated from the carrier by relative movement therebetween.

Description: The present invention relates to a method of transporting stacks of essentially thin, planar products, such as periodicals, books, or newspapers, wherein the stacks are placed on load carriers transported on a transport path. The invention also relates to a load carrier for such transport, and comprising an essentially rectangular bottom and four side walls. A method and a load carrier of the above-mentioned type may be used for example in printing offices, in the transport of stacks of printed products, i.e. books, periodicals, newspapers, advertising material and the like, on a transport path from a stacking machine forwards to a palletizing machine, in packing rooms and in distribution centers wherein printed goods are co-packed for dispatch to subscribers, retailers and regional centers. Another topical field of use is in distribution centers for playing coupons, audio and video cassettes and similar small packages. When constructing and moving stacks or piles of e.g. different newspapers and periodicals, it is of importance to insure a stable form and prevent sliding. In the above-mentioned fields of application this has necessitated a substantial amount of manual effort, both in the formation of piles and during the transport stage, in order to take care of problems with piles sliding during free transport. The known systems in this topical field are limited with respect to automation, flexibility and rapid and safe product handling, and they also require much space having transport paths based on roller, wheel or belt conveyors. A load carrier for the transport of thin, planar objects is known from AU-A-21386/70. It is here the question of a packing case for the transport of so-called glass "blocks", i.e. a block of a number of vertically disposed thin glass sheets. The case is built up in accordance with conventional case-making procedure and comprises four side walls formed from sheets or battens, a lid or "roof" and a bottom or "floor". The glass block is packed within the case also in conventional manner, except that the usual cushioning elements disposed between the case walls and the outer surfaces of the glass block are disposed such that vertically extending spaces or passages are formed inside the case walls, for introduction of depending finger elements on a special lifting grab for lifting of the glass block, possibly together with the packing case. The lifting grab consists of a top plate and four fingers which depend from the top plate and at their lower ends have holes for introduction of through-pins for the support of the load to be lifted. The roof as well as the floor of the packing case are provided with holes in connection with said passages, such that the grab fingers, when lowered by means of a crane, can enter the case through the roof and between the major side walls and the glass block, and descend through said passages down to the floor and possibly through the holes therein. At the bottom of the side walls of the case there are provided holes for introduction of said through-pins. If the case and the glass are to be lifted together, the pins may be applied to the grab fingers underneath the floor. If the glass block is to be lifted out of the case the roof is removed from the case, and the pins are then applied to the grab fingers directly below the glass blocks, through the access holes provided in the side walls. The glass block thereafter may be lifted up from the case, the transverse pins being so short that the end portions thereof pass on the inside of the case walls. It will be appreciated that a packing case of the above-mentioned known construction is especially intended for stable and safe enclosure of breakage-vulnerable sheets of glass. It requires a cumbersome placing of the glass sheets in the case, and also a relatively laborious removal of the glass block from the case. It would not be usable in a transport plant of the above-mentioned type, and its principle of removal of the load could neither be adapted for rational use in such a transport path system. It is an object of the invention to provide a method resulting in a transport plant which is substantially cheaper, less space-demanding, safer and more suitable for automation than the previously known systems used in printing offices or packing rooms today. This object is achieved with a method of the type stated in the introduction and which, according to the invention, is characterized by the steps of placing the stacks in respective basket-like load carriers having a bottom and four sides, each carrier having upstanding wall members defining essentially vertically extending upwards opening slots in at least one pair of mutually opposite sides, and a bottom member having a corresponding opening pattern formed by through-going, upwards opening channels which are open towards and communicate with associated slots, transporting the load carriers on at least one conveyor means forming a continuous closed path and on which the load carriers are slidably retained to allow queuing at work stations along said path, introducing a supporting means directly into bottom channels of a load carrier beneath the stack contained therein, and removing said stack from the load carrier by vertically separating relative movement between the supporting means and the load carrier. Another object of the invention is to provide a load carrier of the introductorily stated type which, by its design, provides for securing the transport of the product types in question, and which is especially advantageous in processes wherein the packaging and/or transport of the products is presupposed to take place automatically. According to the invention, this object is achieved in that the load carrier comprises upstanding wall members defining essentially vertically extending upwards opening slots in at least one pair of mutually opposite sides, and that the bottom is provided with a corresponding opening pattern formed by through-going, upwards opening channels which are open towards and communicate with associated slots. The bottom of the load carrier preferably is provided with a bottom plate which is smaller than the principal dimensions of the carrier, and which is arranged for mounting on a chain conveyor. Thereby a substantial space saving is achieved since chain conveyors are substantially less space-demanding than the conventionally used roller, wheel and belt conveyors. The upwards opening channels of the bottom of the load carrier form through-going cavities between the interior bottom of the carrier and the commodity content. By guiding these cavities towards a fork-shaped hoist means or several narrow, parallel conveyor belts, the content can be separated from the carrier in a simple manner, while both members are in motion and with the least possible disturbance of the content (the stack or pile). The distance between the internal bottom and the content also gives the possibility for strapping of the content while located in the carrier. In this manner the pile is secured against sliding or disengagement, and another form of wrapping can be omitted. By means of the stated method one achieves the substantial advantages that 1) the carrier and its content may be separated while the content retains its movement velocity and direction and the carrier is fed by a continuous chain conveyor, and that 2) the content of the carrier may be strapped while the content rests on the bottom of the carrier. The carrier in addition meets a number of requirements associated with automated transport and co-packaging of the topical product categories. Such requirements are accurate positioning, identification and detection, queuing, alteration of speed of direction on the same conveyor and possibility of processing (e.g. shaking) of the content of the carrier while being in the carrier. When using the carrier according to the invention in combination with a simple, profile-based chain conveyor, not only the above-mentioned objects are achieved, but in addition the speed of the path may be increased, there may be produced piles having more copies per laying (a laying is the number of periodicals arranged with the back side directed the same way from a stacking machine), and the size of the piles may be increased and thereby also the total speed of production. The invention will be further described below in connection with an exemplary embodiment with reference to the accompanying drawings, wherein Fig. 1 shows a schematic perspective view of a load carrier according to the invention; Fig. 2 shows a sectional side view of the load carrier with content; Fig. 3 shows a sectional side view of the load carrier, taken at right angles to the section in Fig. 2; and Fig. 4 shows a cut of a conveyor with load carriers according to the invention. As appears from Fig. 1, the load carrier according to the invention is a basket-like device having four sides 1, 2, 3 and 4 and an essentially rectangular bottom 5. At least one pair 1, 3 or 2, 4 of the mutually opposite sides is provided with one or more upwards open openings or slots which are aligned with each other on the opposite sides, for example the slots 6, 7 in the sides 2, 4 and the slots 8, 9 and 10, 11 in the sides 1 and 3. The sides may be formed by plate-shaped elements defining in pairs an intermediate slot, like the elements 12, 13 of the side 1 and the elements 14, 15 of the side 3. As an alternative, the sides may be constituted by two or more sticks or rods, such as the sticks 16 and 17 in Fig. 1, the sticks being inserted in suitable holes in the bottom member. The sides on the short and/or long sides may be at least partly diverging, i.e. slightly inclined outwards throughout or along parts of their length, for example as shown for the sticks 16 and 17. Thereby one achieves a simpler separation of the carrier and its content, and it may be simpler to supply a load to the carrier. In Figs. 2 and 3 such a load is shown in the form of a stack 18 of thin, planar products of different dimensions, e.g. a stack of different newspapers or periodicals (magazines). The bottom 5 of the carrier consists of an inner and an outer bottom portion 19 and 20, respectively. The outer bottom portion is constituted by a rectangular, preferably square bottom plate 21 which, as shown, is smaller than the principal dimensions of the carrier and is adapted for mounting on a chain conveyor, with the load carrier oriented either longitudinally or transversely of the conveyor path. The bottom plate possibly may be formed with not illustrated positioning recesses, identification discs or codes. The inner bottom portion 19 of the carrier is formed with a plurality of upwards open channels 22 and 23, respectively, extending longitudinally and transversely of the bottom and forming an opening pattern corresponding to or cooperating with the vertical slots in the walls 1 - 4 of the carrier. The channels thus open into the appurtenant slots, while the channels 22 which on one side are defined by the side walls 1 and 3, in addition have lateral openings passing into the appurtenant slots and being aligned with respective ones of the crossing channels 23. The inner or internal bottom portion thus has raised supporting points between the channels which in turn form upwards and laterally open cavities between the content (the load) of the carrier and its internal bottom. These cavities render it possible to introduce an object underneath the content of the carrier from the side. It will be appreciated that, in the present context, the terms "slot" and "channel" should be interpreted in a wide sense. Thus, the term "slot" is intended to cover all kinds of wall openings extending throughout the wall height, and the term "channel" is intended to cover all kinds of upwards open bottom recesses interconnecting wall slots belonging together in a functional sense. The built-up bottom between the longitudinally extending channels 22 has, as shown, laterally projecting elements 24 which, at least on the underside, are provided with a bevel or chamfer 25. The chamfer may consist in that the projecting portions are cut along a sloping line from the bottom plate 21 to the projecting elements. Such chamfers may also be provided both in the longitudinal direction and in the transverse direction. Thereby transport is admitted in curves of the transport path having a relatively small radius of curvature. Out of operational or productional considerations, all of the elements in the bottom and side structure may be rounded in corners. The carrier may be constructed so that the mutual distances of the walls are adjustable, in order to be able to adjust the size of the carrier, for example by having sides which can be pushed towards or away from each other (not shown), or by having holes 26, 27 of varying mutual distance, as shown in Fig. 1, for suitable placing of the side wall sticks 16 and 17. The carrier may be formed from any suitable material, e.g. moulded plastics or metal. In an advantageous embodiment, the carrier comprises a bottom member consisting of a one-piece plastic or metal casting, and side walls constituted by a number of upstanding sticks placed in suitable holes in the bottom member. Various possible working operations in connection with the carrier will be described in the following with reference to Fig. 4. This Figure shows a cut of a driven chain conveyor 28 on which there is shown a load carrier or basket device 29 having a commodity content in the form of a stack 30, and an empty basket device 31 on a return basket path. The commodities which are to be transported, are dropped into the load carrier (in the following called basket) from a stacking machine, or from other automatic picking and counting machines, or by manual effort. The basket may also be filled by moving it vertically or obliquely upwards towards a stack or pile being at rest or moving with an adjusted speed. Strapped piles may be destrapped after having been placed in the basket, by gripping the strap manually or mechanically, cutting the strap and pulling it away from the basket. Piles which are covered with plastic, in a similar manner may be freed from the plastic while being located in the basket. Further, stacks may be strapped while being situated in the basket. This is done by carrying one end of a strap underneath the content of the carrier and through one of the bottom channels, while the other end of the strap is taken over and around the stack, and the strap is tightened and the end portions tied or welded together. There may be used one or more straps, crosswise or parallel. The basket is separated from its content by introducing a fork-shaped hoist means in the bottom channels of the basket, longitudinally or transversely of the basket, beneath the content of the basket. Thereafter the content is lifted out, or the basket is dropped, or the basket and the content are separated gradually during speed while the vertical mutual distance increases, for example in that the basket follows a sloping portion of a return path, as shown in Fig. 4. In the latter case the fork means will consist of two or more narrow, parallel conveyor belts 32. In Fig. 4 there is also suggested as an example that finished packages or bundles 33 and 34 are carried via the transport means 32 forwards to an additional transport means 35 on which the packages are carried further to e.g. a shrinkage tunnel for plastic wrapping.

Claims: A method of transporting stacks of essentially thin, planar products, such as periodicals, books, or newspapers, wherein the stacks are placed on load carriers transported on a transport path, comprising the steps of placing the stacks in respective basket-like load carriers (29) having a bottom (5) and four sides (1-4) each carrier having upstanding wall members defining essentially vertically extending upwards opening slots (6-11) in at least one pair of mutually opposite sides, and a bottom member (5) having a corresponding opening pattern formed by through-going, upwards opening channels (22, 23) which are open towards and communicate with associated slots, transporting the load carriers on at least one conveyor means forming a continuous closed path and on which the load carriers are slidably retained to allow queuing at work stations along said path, introducing a supporting means directly into bottom channels (22, 23) of a load carrier (29) beneath the stack (18) contained therein, and removing said stack (18) from the load carrier by vertically separating relative movement between the supporting means and the load carrier. A method according to claim 1, wherein each load carrier (29) has vertically extending slots (6-11) aligned in pairs longitudinally (6,7) of as well as transversely (8-11) to the transport direction along said path, CHARACTERIZED by the additional step of strapping the stacks alone while being in the respective load carriers (29), one end of a strap being introduced through a bottom channel (23) of a carrier transversely to the transport direction, the other end of the strap being taken over and around the stack (18) along and through the associated vertical side slots of the carrier sides and fixed to said first end after tightening of the strap. A method according to claim 1 or 2, CHARACTERIZED IN that the stacks (18) are removed from the respective load carriers by introducing a stationary supporting means comprising two or more narrow parallel conveyor belts (32) extending in the transport direction into respective load carrier bottom channels, and thereafter vertically separating the load carrier from the supporting means by said load carrier continuing its movement along a sloping portion of the conveyor path, so that the stack is taken over by said conveyor belts (32). A method according to claim 2, CHARACTERIZED IN that the stacks (18) are removed from the respective load carrier by introducing a supporting means comprising a fork-shaped hoist means into carrier bottom channels extending transversely to the transport direction while the carrier is held stationary at a removal station, the stack (18) thereafter being lifted out of the carrier (29) by moving the hoist means along associated vertical side slots of the carrier. A load carrier for transporting a stack of essentially thin, planar products, such as periodicals, books, or newspapers, and comprising an essentially rectangular bottom (5) and four side walls (1-4), CHARACTERIZED IN that it comprises upstanding wall members (12-17) defining essentially vertically extending upwards opening slots (6, 7 resp. 8, 9 and 10, 11) in at least one pair of mutually opposite sides (1, 3 resp. 2, 4) and in that the bottom (5) is provided with a corresponding opening pattern formed by through-going, upwards opening channels (22, 23) which are open towards and communicate with associated slots. A load carrier according to claim 5, CHARACTERIZED IN that the bottom (5) is provided with a bottom plate (21) which is smaller than the principal dimensions of the load carrier and which is arranged to be mounted on a chain conveyor (28). A load carrier according to claim 2 or 3, CHARACTERIZED IN that the side walls (1 - 4) are at least partly diverging. A load carrier according to any of the claims 5 - 7, CHARACTERIZED IN that at least two mutually opposite side walls (2, 4) are formed by sticks (16, 17). A load carrier according to claim 8, CHARACTERIZED IN that it comprises a bottom member (5) consisting of a one-piece casting, and side walls constituted by a number of upstanding sticks (16, 17) places in suitable holes (26, 27) in the bottom member (5). A load carrier according to any of the claims 5 -9, CHARACTERIZED IN that the mutual distances of the side walls (2, 4) are adjustable.

Inventors: HOGNESTAD, JON, SELVIG, EINAR K.
Applicants: MEDIA CRAFT A.S.
Application year: 1989
Main classification: B65G35
IPC codes: B65G65, B65G47