The present invention relates to a method of building up portions of foodstuff objects orderly arranged in or on package members such as trays or plates to form weight determined portions ready for final packaging, in particular slices of salmon or of other more or less precious materials.
It is known that in direct association with slice cutting machines it is possible to arrange for means operating so as to deliver the consecutively cut slices in groups laid out in imbricated formation on conventional 'salmon boards', which are special cardboard pieces suited to act as carriers for the slices in sales packings completed by a film wrapping making the products visible to the customers. Normally, the equipment is adjusted so as to deliver to the plates a predetermined number of slices, but since - as readily appreciated - the slices will vary in size or at least not be of uniform size through longer periods, the different groups are liable to exhibit different weights, whereby they are almost bound to be weighed and price marked individually.
Another practice is to arrange the slices manually on the plates, whereby it is possible to aim at a fixed weight and thus a fixed price by selecting exposed slices of appropriate size and number, but this, of course, is rather laborious.
The present invention is based on the consideration that it is possible, for one thing, to adapt a known distribution technique to automatize the selection of slices for collection of portions of a desired weight, and, for another thing, to adapt this technique so as to enable a delivery of the slices or the slice groups directly or practically directly to the single package plates or trays, such that the manual work can be reduced to a neat rearranging of the slices on the plates.
The known technique here referred to is the one practiced by grader or batching systems comprising a feeder conveyor for supplying the objects one by one to a dynamic weighing unit that will weigh the single objects and store the weighing results in a memory and calculating unit. Thereafter the objects are brought further along a sorter conveyor having at one or both sides a row of receiver stations, while also being equipped with selectively actuatable diverter means operable by said memory unit to divert the single objects into selected receiver stations so as to build up therein collected portions of objects amounting to some predetermined total weight. The memorizing/calculating/-controlling unit serves to direct each object into the receiver station best fitted for receiving just that object in order to end up with a complete portion of the prescribed weight, see e.g. GB-2,116,732 which covers the preamble of claim 1.
As mentioned below, it may be required to adapt such a sorter system in a special manner in order to make it handle thin slices, but according to the invention a still more important adaptation is arranged for by con-verting the receiver stations from being just 'receiving stations', in which the single object portions may be collected in a container from which the portions can be let out for further processing in that there is arranged, at each receiver station, means for supporting a package plate or tray member as referred to. The objects may not be delivered particularly neatly to the single receiver stations, but an operator's job will be reduced to provide a neat arrangement of the final group of objects at each single package member, without caring about the weight of the portions. Thereby the operators will greatly improve their operation capacity.
It should be mentioned that the grading technique has been developed so as to be able to operate at relatively high speed, handling e.g. some 120 objects per minute, and of course it is desirable to actually make use of such a high speed operation. However, this implies that the objects are to be transferred from the sorter conveyor to the receiving stations in a very fast manner, which is well possible in connection with objects conventionally handled by this technique, e.g. chickens of fishes or large pieces thereof. The said diverter means usually consist of a wing or blade member, which, when operationally selected, is swung from a position along one side of the conveyor to a position in which it projects across the conveyor belt, obliquely downstream of the belt and towards the receiver station at the opposite side of the belt. In slow operating systems the objects will then be caused to slide or roll along the oblique wing out to the receiver station by the driving action of the moved belt, but in high speed systems this will not be the general picture of the operation. In that connection it will be required that the wings be actuated so rapidly that they will operate in quite a different manner, viz. by imparting to the objects a dynamic throw-out action, whereby the objects are thrown out to the respective receiver stations.
This is acceptable as long as the objects are solid units which may hit some receiver plate of the receiving station and readily fall down therefrom into a receiver container, but when thin slices are concerned the picture changes completely in that such slices tend to adhere to the surface they are thrown against. Thus, the slices cannot be expected to readily seek down to the bottom area of a receiver station, at which there may be placed a packing plate or tray in accordance with this invention, and for this reason it is important that one or more operators be available for supervising the factual delivery of the slices to the receiving stations, thus even for scraping off the said adhering slices in order to bring them to the packing plate at the bottom of the station. It is an advantageous measure, therefore, to arrange the receiver stations to be operator attended stations, in which an operator may attend both to the delivery of all received slices to the packing plate and to the neat arrangement of these slices on the packing plate.
These actions may be performed in two steps, viz. first collecting the slices into a well confined group on the packing plate without much or any rearranging, then transferring the plate to a nearby working plate in the receiver station to make the latter reoperative without delay, and then making the rearranging of the slices on the plate. A further possibility could be to collect the slice group on a rigid bottom plate end cause the entire group to be transferred to the packing plate, e.g. in the said working position thereof, whereby the packing plates themselves should not be present in the very receiver means of the stations.
It has been found that the conventional diverter wings can be modified to better suit the present invention. They may well be suited to divert even rather thin slices, but they affect the slices in different ways, causing some slices to be merely scraped or thrown off the belt, while other slices are consecutively turned when hit by the vertical side wall of the wing, such that they are thrown out with their orientation changed. For mere grouping purposes this could be fully acceptable, but in particular as far as smoked salmon is concerned it is desirable to maintain a uniform orientation of the slices presented on the packing plates, in order to expose the same colour on the visible edges of the slices, and the work will be made difficult for the operators if they shall not only rearrange the slices neatly, but also turn the direction of a large percentage of the slices.
On this background it has been found possible to design the diverter wings in such a manner that practically all slices will be delivered with uniform orientation, viz. such that they will all, with a high degree of safety, be turned by overfolding when diverted by the wings. To this end, the wings are preferably profiled as stated in claim 8, as explained in more detail below. All according to the nature of the slices it may be necessary to seek to adapt the receiving stations for an easy running of the operation. At one extreme, viz. if the slices are hard frozen, they will simply be pushed or thrown off the grader belt, typically with a force depending on whether they are hit by a diverter wing portion having a higher or lower velocity, i.e. whether hit by e.g. the wing tip or a middle wing portion; when the slices are hard and non-sticky, this will not make any big difference, because the slices may be thrown against an outermost wall portion of a receiver container having a hopper shaped bottom portion leading the readily downfalling slices to a relatively narrow bottom area representing the dimentions of the packing plates.
Normally, however, the slices will not be hard frozen or non-sticky, and they will tend to stick to the said outermost container wall portion, if they are thrown against it. Experiments have shown that a possible solution can be to arrange for an outward retraction of these wall portions such that they will only exceptionally be hit by the diverted slices, while using underneath the trajectory of the diverted slices a collector conveyor bringing the downfalling slices down to the said bottom area of the receiver container. However, even such a system presents certain difficulties.
Another attempt to modify the receiver containers was based on the use of a low-friction plastic material for the container walls, facilitating an easy sliding down of the sticky slices onto the narrow bottom of the receiver container, contrasted to the conventional use of metal walls, but the efficiency of this system, though sufficient for some products, was not found satisfying for the handling of smoked salmon slices at temperatures well above 0°C.
It was found almost unavoidable that some slices would adhere to the catching wall of the receiver container, without readily sliding down, and it was realized that a more effective solution could be based on two different principles, viz. 1) arranging the catching wall portions so as to be slanting downwardly and outwardly, whereby the gravity could assist in liberating the slices from their sticked positions, and 2) arranging for receiver wall areas operable to be tilted upside down or at least through such a substantial angle as to make received slices generally turning downwardly, for facilitating an easy release and downfall thereof. These aspects of the invention, as claimed in claim 11, will be discussed in more detail below.
In the following the invention as a whole will be explained in more detail with reference to the drawing, in which:-
The system shown in Fig. 1 comprises a feeding belt 1 serving to bring mutually separated objects 2 to a weighing belt 3 forming part of a dynamic weighing system connected with a computer 4. Thereafter, the objects 2 are moved further on a conveyor belt 5, along one side of which there is provided a row of receiver stations 6, while at the other side of this belt there is arranged, correspondingly, a row of diverter wings 7, which, controlled by the computer 4, are operable to be swung inwardly over the belt 5 so as to thereby effect a diversion of weighed objects 2 to any selected station 6. It is indicated by an arrow that the swinging-in of the diverter wings may take place with such a velocity that an object 2 hit by the wing will be directly thrown out towards the selected station 6.
In the embodiment shown in Fig. 1, each station 6 comprises a receiver section 8 made as an outwardly and downwardly slanting roller conveyor with very thin conveyor rollers 9, e.g. only some 5 mm thick, leading down to a collector section 10, next to which there is located a magazine 11 for packing plates or trays. Along the row of stations 6, opposite to the belt 5, there is provided a strip shaped table 12, outside which a take-away conveyor 13 is arranged.
The downwardly slanting roller conveyor 8 will serve to receive all slices thrown off from the belt 5 and guide them down to the section 10, in which they are deposited, optionally assisted by an operator, on a packing plate or tray furnished from the magazine 11. When a portion is completed, e.g. signalled to the operator by way of the computer 4 actuating a signal lamp at the relevant station, the filled plate or tray may be transferred to the table 12 by the operator or by automatic means, and then a new plate or tray can be fed from the magazine 11, enabling a rapid reactuation of the receiver station 6. The operator may then, on the table 12, effect the required rearrangement of the collected slices and thereafter push the packing plate or tray onto the conveyor 13 for delivery thereof to a packing station.
Thus, the collector stations 10 and the table 12 will constitute handling stations usable for the operators to arrange the products as desired. The primary purpose of these handling stations is to enable a "preparation for packaging", viz. an orderly arranging or rearranging of the articles on the packing element, this per se not mounting to a packaging operation. Thereafter the final and real packaging may well take place in a "packing station" as in connection with conventional graders.
A non-illustrated alternative can be to avoid the roller conveyor 8 and provide the section 10 as a bottom portion in a hopper like receiver bin placed closer to the belt 5, with outermost upstanding wall portions for catching the slices thrown off from the belt 5, these walls being made of a low friction material and/or with a surface profilation promoting an easy sliding down of the slices caught by these wall portions.
As mentioned, it may be a problem that the wings 7 may cause the slices 2 to be rollingly overfolded rather than just pushed or thrown off the belt 5, whereby the orientation of such slices is changed. After many experiments a rather simple solution to this problem was found, viz. in profiling the wings as shown in Fig. 2. At its lower end the wing 7 is provided with a protruding scraper edge 14 having above and in front of it a protruding root face 14. Even more or less thawn salmon slices may then be displaced on the belt 5 rather than overrolled thereon, at least with highly increased security. The operators may well accept a few turned slices now and then.
The receptacles 6 should have a length in the longitudinal direction of the belt 5 longer than the normal width of a packing plate in order to allow for some spreading of the throw-out form the associated wings 7. Upstanding outer walls should receive the slices not directly hitting the packing plates at the bottom, and the slices should be guided so as to be delivered to the relatively narrow bottom plate, if required with some manual assistance, though as little as possible. As described in connection with Figs. 3-7 it has been found possible to design a receptacle widely fulfilling these requirements.
One such receptacle unit is shown in an exploded view in Fig. 3 and in assembled condition in Fig. 4. The unit has a rear plate portion 16 with obliquely forwardly extending wing plates 18 and with a slightly upwardly and forwardly inclined orientation. The triangular spaces in front of the wing plates 18 are occupied by separate triangular bottom plates 20 that are slanting slightly downwardly towards each other and each having an upstanding outer plate portion 22 extending closely along the wing plate 18 located therebehind, and a horizontal innermost edge portion 24. Each of the elements 20-24 is pivotally suspended by means of pins 26, whereby they are tiltable from the position shown in Fig. 4, which is also shown in full lines in Fig. 7, to the position shown in dotted lines in Fig. 7.
As apparent from Fig. 4, the horizontal plate edge portion 24 extend parallel to each other with a certain mutual distance, viz. such that they are suited to carry between them a loose bottom plate 28, which, as shown particularly in the top view of Fig. 6, may well extend further outwardly underneath the rear plate 16, the edge portions 24 being correspondingly extended.
Fig. 5 is a cross sectional view of the conveyor 6 with an associated lateral view of a receptacle, in which a bottom plate 28 i shown rested on an edge plate 24.
As slices are received by the receptacle the slices will predominantly be delivered to the bottom plate 28, though also with overlapping to the triangular bottom portions 20. Some slices may be thrown against the wing sides 18,22 and even stick thereto.
When a receptacle has received a complete slice portion the computer 5 will actuate suitable means (not shown) for pivoting the bottom portions 20-24 to the position shown in dotted lines in Fig. 7. A first result of this will be that the plate edges 24 will be withdrawn from the support plate 28, such that this plate will fall down to an underlying, fixed plate portion 30, Fig. 7, while a subsequent result is that slices happening to stick to the plates 20,22 get the opportunity to fall down therefrom by the associated inward pivoting of these plates. The pivoting make take place at high speed and with an abrupt stop, whereby adhering slices will be thrown off so as to fall down on the top of the slices on the plate 28 as already fallen down. An operator may then take out the plate 28 and manually rearrange the slices neatly thereon. Also, the operator may visually inspect the receptacle and release slices happening to still get stuck thereto. In particular when the slices are still cold the receptacles will be liable to completely empty themselves onto the support plate 28, requiring only sporadic assistance from the operator.
A new support plate 28, also referred to as a packing plate, may thereafter be placed on the plate edges 24 by the operator, once the plate systems 20,22 have been swung back, and the operator may actuate a switch informing the computer of the renewed operability of the receptacle. It is preferred, however, to make use of an automatic feeding of the plates 28 from a magazine 32, Fig. 7, by means of suction cups and an associated movement system. Preferably, use is made of a lateral feeding to the area beneath the opened bottom portions 20 and then a raising to the normal position of the carrier plate 28, which will then be stabilized by a reclosing of the bottom portions 20, as the plate edges 24 will then be brought into position beneath the side edges of the plate 28. Thereafter the suction cups are released and moved back to the magazine.
The inwardly slanting configuration of the upstanding walls will contribute to make the slices less adhering to these walls, as the gravity will seek to loosen the adherence.
Of course, the bottom plate 28 could be a system part, from which the collected slice portions could be transferred to individual packing plates, but it will be appreciated that these plates 28 may perfectly well be the packing plates themselves. Once the operator has completed the rearrangement of the slices on such a plate, the latter may be delivered e.g. to a conveyor belt for bringing it to a further processing unit or to a final packaging station.