METHOD FOR SUPPLYING SACKS TO THE SACK APPLICATION DEVICES OF SACK FILLING PLANTS, AND AN ARRANGEMENT FOR IMPLEMENTING THE METHOD

Abstract: The sacks bound into packs by means of straps are unbound during their travel towards a sack application device by cutting the strap or straps which bind them, making the cut in a portion of the strap or straps which has been spaced apart from the pack. The cut straps are removed from the unbound pack, which then reaches the sack application device. The arrangement comprises conveyors (3, 13) for conveying the bound sacks to a station (11) for cutting and removing the strap or straps, and from this to a sack application device (M).

Description: This invention relates to a method for supplying sacks of any type, whether of glued or sewn, open mouthed or valve type, to a sack application device, the known purpose of which is to apply said sack to the delivery nozzle or mouth for the powder or granular material which is to form the sack contents. Both sack application devices and sack filling machines possessing delivery nozzles or mouths arc well known, especially in the cement industry, where such sacks are filled with cement. The invention also relates to the arrangement for implementing the method. The method and the arrangement are of the kind recited in the preamble of claims 1 and 2, respectively, of the attached claims. An apparatus and method of the kind recited in the preambles of attached claims 1 and 2 is illustrated in GB-A-2 076 355, which refers to an apparatus for taking off a band wound about a paper sheet bundle. This prior art apparatus comprises a band-removing section. This section comprises a bundle-bending mechanism provided with a pair of clamping members to confere an arcuate shape to the bundle and, further, a bend stripping hooking member for the stripping (removal) of the band by acting on a not-arcuated portion of the band which separates from the bundle. The known apparatus is of rather complicated nature because one of the clamping members has to be raised and lowered intermittently. The feeding of the bundles is an intermittent one (i.e. not continuous). The band must be located on the bundle within a specific range of positions and is not cut but only stripped off from the arcuated bundle with the risk of breaking it during the stripping phase due to friction so that no removal is attained. With particular but not exclusive reference to the cement industry, it is well known that the handling of the empty sacks involves a human element which negatively affects the costs of the sack filling operation. The main object of the present invention is therefore to reduce the costs of a sack filling plant for the sector concerned, and particularly for a cement factory, by reducing the labour currently required, accelerating the handling of the empty sacks, and increasing the self-sufficiency of the sack filling machines. This and further objects which will be apparent from the detailed description given hereinafter are attained by a method and an arrangement whose inventive features are recited in the characterizing clause of their respective attached claims. The invention will be more apparent from the detailed description of a preferred embodiment thereof given hereinafter by way of non-limiting example and illustrated on the accompanying drawing, in which: Figure 1 is a perspective schematic view of a pack of sacks bound with a binding in the form of two conventional straps; Figure 2 is a plan view of the arrangement of the invention; Figure 3 is a schematic view in the direction of the arrow A of Figure 2; Figure 4 is a schematic partial longitudinal section on the line IV-IV of Figure 2; Figure 4A is a schematic longitudinal section on the line IVA-IVA of Figure 4 through a detail of the cutting means just before they act on the binding; Figure 5 is a schematic section on the line V-V of Figure 2 after the pack binding has been cut; Figure 6 is a schematic section on the line VI-VI of Figure 2 during the stage in which the cut binding is being removed from the pack of sacks; Figure 7 is a schematic view in the direction of the arrow B of Figure 6. The sacks are produced by specialist industries, ie by sack factories, on the basis of a substantially automatic cycle. The sacks are grouped, for example automatically, into packs. The packs are transferred to a conventional strapping machine which binds them. The bound pack, indicated by P, is shown in Figure 1, the binding being formed from two straps indicated by R. The packs P are disposed in layers on a conventional pallet, shown in Figure 3 where it is indicated by Z. Each layer comprises a predetermined pack arrangement. To place the packs P on the pallet Z a known palletizer can be used, such as of the type described in another patent in the name of the present applicant, for placing full sacks on a pallet. In known manner, the assembly of packs situated on the pallet Z is fastened to the pallet to prevent any displacement of the packs during their transportation. In some cases a plastic wrapping, such as of heat-shrinkable type, can also be provided to protect the packs from the weather. The loaded pallet is despatched by conventional means of transport such as trucks to the sack filling plant, for example of the cement factory. It is here unloaded and the means used for fastening the pack assembly to the pallet and the possible heat-shrinkable protective wrapping are removed. The pallet Z together with the assembly of packs P is loaded onto a roller conveyor 1 which conveys it to a depalletizing station 2 of known type, the purpose of which is to unload the packs P from the pallet Z one by one and to transfer them to another conveyor 3, such as of roller type, arranged parallel to the preceding. In the non-limiting example considered here, the withdrawal and transfer station 2, ie the depalletizer, comprises a load-bearing structure 4 of bridge shape extending over the two conveyors 1, 3. The structure 4 carries longitudinal guides 5, ie parallel to the conveyors, along which a carriage or slide 6 can move in both directions driven by conventional motor means, not shown. The carriage 6 comprises guides, only partly reproduced and indicated by 7, along which a further carriage or slide 8 can move in both directions. This latter therefore moves in a direction perpendicular to the movement of the carriage 6 and conveyors 1, 3, driven by conventional motor means, not shown. The carriage 8 lowerly carries a head 9 provided with suckers 10 for gripping the packs P. The head 9 is not only able to rotate about a vertical axis X but is also able to move upwards and downwards. Conventional motor means, not shown, effect these movements of the head 9. By virtue of the described construction, the station 2 is able to withdraw one pack P at a time from the pallet Z and transfer it to the conveyor 3. Before it reaches a station 11 for the cutting and removal of the binding, the pack P which has arrived on the conveyor 3 is centered on said conveyor by adjustable stationary lateral guides 12. The conveyor 3 terminates at the entry to the station 11, in which the pack P is made for example to advance by two endless parallel belts 13 driven by conventional motor means, not shown. For the purpose of supporting and moving the packs, the belts 13 are provided with projecting appendices 13B on which the pack P rests. During its advancement, the pack P encounters a stationary member 50, for example of sheet metal, the purpose of which is to insert its thinned or tapered front end 51 between the lower side R1 of the straps and the pack P (Figures 4 and 4A) in order to form, by means of its hollow or arcuate rear part 52, a separation region P1 thereat between the pack P and the side R1, in which a rotary blade 14 can operate to cut said side. In addition, the rear part 52 of the member 50 protects the pack from the blade. After the side R1 has been cut it produces two free ends R′1 (Figure 5). On leaving the belts 13, the pack is carried on a roller conveyor 17 having a width less than the width of the pack P and such that the free ends R′1 of the binding hang freely to the side of the pack, as shown in Figure 6. To the side of the conveyor 17 (see Figures 2, 6 and 7) there is provided a means for removing the cut bindings R from the pack P. This means is indicated overall by 18C and comprises in this example a pair of belts 19 which are very close together and are driven at speed exceeding that with which the pack P advances along the conveyor 17. The belts 19 are arranged as follows: a) inclined to form an acute angle (alpha) to the direction F of advancement of the pack P, and b) such that one of the free ends R′1 of the binding R can be gripped between the two belts 19 and removed from the pack. To facilitate the insertion of the end R′1 between the belts 17, lead-ins such as those indicated by 20 can be provided. To ensure that the binding is removed if the belts 19 fail, an identical device (indicated by 18′ in Figure 2) can be located on the other side of the conveyor 17, but more downstream than the device 18 to which the belts 19 pertain. The unbound pack now free of its binding then passes to a conventional sack application device indicated by M. The invention also covers an embodiment in which the part which unbinds the packs is incorporated into or forms an integral part of the sack application device,

Claims: A method for supplying sacks of sewn or glued, open mouthed or valve type, to sack application devices the purpose of which is to apply the sack to the delivery nozzle or mouth for powder material (eg. cement) or granular material which is to form the sack contents, wherein the sacks bound into packs (P) are unbound either in the sack application device or during their travel towards this latter by forming a region (P1) in which the binding (R) is separated from the packs (P) and the thus separated binding is removed from the packs, characterized in that the packs (P) while in motion are subjected to the region-forming phase, to the cut in the binding by rotary cutting means (14) in the separated region (P1) and after the cutting to the removal of the cut binding (R). An arrangement for implementing the method of claim 1, said arrangement comprising means (3, 13) for feeding the bound pack (P) of sacks to a region-forming means where the binding (R) is separated from the pack (P) so as to expose a separated portion (R1) of the binding (R) to the action of binding-removal means, characterised in that a) the feeding means (3, 13) are continuously moving feeding means; b) the region-forming means comprises a stationary member (50) which inserts between the binding (R) and the pack (P) while the pack is moving; c) the binding removal means comprises a spatially stationary cutting member (14) for cutting the binding at its separated portion (R1) while the pack is moving and driven gripping means (18) for gripping the free end (R'1) of the cut binding so to have the binding taken-off the pack when the pack is moving. An arrangement according to claim 2, characterized in that the cutting member is a rotary blade (14). An arrangement according to claim 2, characterized in that the gripping means (18) comprises cooperating mobile belts.

Inventors: MOLTRASIO, MARIO
Applicants: MOLTRASIO, MARIO
Application year: 1990
Main classification: B65B69
IPC codes: B65B69