The present invention relates to a band-saw including several blades for cutting blocks, e.g. frozen fish-blocks, into several slices.

At the manufacturing of e.g. fish-pins, one starts from big frozen fish-blocks (about 0,6x0,25x0,5 m) which are divided in three long stocks, 5 so called loaves. Those loaves are sliced longitudinality into several slices, usually 3-6, which finally are cut transversally in order to pro¬ duce fish-pins or bigger portion pieces.

The first cutting of the block is usually made by means of a dubbel band-saw, i.e. two identical band-saws positioned beside each other, 10 whereby the fish-blockis fedperpendicular to the saw blades. In this way, the cutting is made in a single operation. Alternately, the cutting of the block into loaves is made by a single saw in several operations.

The final sawing from slices to portion bits is usual made by feeding the slices transversally over several disc saw blades, which are spaced 55 from each other a distance corresponding to the width of the desire fish- - pin or portion piece. Also this partition can be made in a single operation. The sawing operation which constitutes a problem today is the slicing of the loaves into slices.

It is not possible to make this slicing in the same manner as the 20 partition of the portion pieces, i.e. to use several parallel disc saw blades. If so, sawing depth must be at lease equal to the width of the loaf, i.e. between 8 and 9 cm and in order to avoid unnecessary spill and in order to achieve a fine cutting surface, which is essential for the appearence of the final product, the saw blade must be wery thin, about 5 0,4 mm. Such a thin blade would vibrate very heavily and would not give any high precision and would not withstand the high loads appearing

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at sawing of deep-frozen blocks.

Thus, the use of a band-saw is ultimative. However, the above-mentio¬ ned dubbel band-saw will give a maximum of threesiices in the same opera¬ tion. This slicing operation is today proformed by slicing each single slice in a single band-saw. This means that in order to achieve five slices, the loaf must be fed through the saw four times, and so on.

Thus, said operation cannot be included in a fully automatic chain, since it has to be preformed manually which is very time consuming and expensive.

According.to another known method, the loaves are sliced by means of a device comprising five separate band-saws positioned after each other. However, this device has several drawbacks. It is about five meter long and is thus very bulky, which makes it unsuitable for smaller industries. The investment costs are high and the time and expences for cleaning and service are considerable. Moreover the sawing spill must be collected at several positions.

The object of the present invention is to provide a band-saw for sli¬ cing a desired number of slices in a single operation. Such a band-saw can be included in a fully automatic chain.

Another object of the present invention is to provide a band-saw which lacks the above-mentioned drawbacks.

Said objects are achieved by a band-saw for slicing a block of e.g. deep-frozen fish, into slices, wherein two drums are arranged on a support. At least two endless band-saw blades are mounted on said drum close to and adjacent to each other. At least one guiding for each saw blade is positioned between the drums and is adapted to twist each saw blade a certain angle in relation to the axis of the drum. The guiding compri¬ ses inserts of a hard metal which guides the saw blades so that each saw blade is completely parallel with the adjacent saw blade.

Further objects and advantages of the invention will appear more • closely from the description below of a preferred embodiment of the in¬ vention during reference to the appended drawings.

Fig. 1 is a perspective view of the band-saw from the front portion and with the front cover removed.

Fig. 2 is a perspective view corresponding to fig. 1 wherein the feeding direction of the fish block is shown.

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Fig. 3 is an elevational view and shows the guiding unit for the saw blades in details.

Fig. 4 is a schematic view showing the adjustment of the guide inserts. Fig. 5 is a perspective view over the saw blade guiding unit. Fig. 6 is a side view of the frame of the band saw.

Fig. 7 is a cross-sectional view through the surface of the pulley. Fig. 8 is a perspective view of a fish-block cut and sliced according to the invention.

In figs. 1 and 2, the band-saw according-to the invention is schemati- cally shown. The band-saw comprises a frame 11 which is supported by two supports 7. The band-saw has a front side 2, a back side 3, a cover 5, a bottom 6 and two sides 4. An operating panal 8 is arranged on one side 4 and a device 9 for feeding out of saw spill is mounted on the other side 4. Inside the frame there are several, and at least two saw blades 12, which extend around two pulleys or drums 10 and through two parallel blade gui¬ ding units 13, which are described in more details below. The saw blades 12 are placed adjacent each other. A cutting and feeding plane 17 is ar¬ ranged in connection with the blade guiding units and passes through the front side 2 (see fig. 2). A knob 15 is arranged to incline the frame. In order to strech and tension the saw blades there is connected a hand- lever 16 and a pneumatic saw blade tension unit 14.

The saw blade guiding unit 13 comprises two or several twisting units 34 (such a detail is shown in fig. 3, compare also fig. 5) which are placed each side of the cutting plane 17. In the twisting units there are inclined grooves 23, one for each saw blade, which receives the saw blades and is enlarged into a hole at its end! In each such hole there is placed a blade guiding 25 and below there is a lock plate 19, which together with the lock screw 18 locks the blade in a predetermined position. The blade gui¬ ding 25 comprises metal bits or inserts 20-22, which support the blades exactly n position and preferably is made of hard metal in order to resist wear. The blade guidings are also provided with a blade groove 24. When the saw blade is to be put in place it is firstly introduced through the inclinedportion of the groove 23. The blade guiding 25 is placed for re¬ ceiving the saw blade and the groove 24 is positioned in line with the inclined portion of the groove 23, whereby the saw blade can pass down in the groove 24. Thereafter the saw blade is pivoted or twisted to the desi¬ red position by means of the blade guiding, whereupon it is locked by means of the lock plate 19 and the lock screw 18.

In more details, the twisting unit consists of a metal block 35 made in one piece and comprising a plurality of bores 36, one for each saw blade. The groove 23 connects the bore with the upper surface 37 of the block. Below each bore, there is an elongated hole 38 as is shown in broken lines in Fig. 3. A screw extends through each bore and secures a washer 39 in plac which constitutes the lock plate 19. The washer 39 has a segment thereof cut off in order to expose a plane surface 40.

The blade guiding 25 is made of a cylinder having the same length as the thickness of the block 35. The inserts 20 - 22 are attached to the cylinder by bolts 41 in order to define said saw blade receiving groove 24. Thus, the saw blade 12 is received between the inserts 20 and 21, which defines the plane of the saw blade. The backside of the saw blade abuts the insert 22 and the cutting teeth thereof are positioned in the enlarged area to the right in Fig. 3. At least the end portion of the cylinder 25 has recessed portons 42 and 43, which present plane surfaces for cooperation with the washer 19. Thus, each cylinder can be withdrawn and inserted from the backside of the metal block 35. However, the position of each individual cylinder will be completely defined by the washer 19. When the cylinder is twisted or pivoted as shown in the righthand portion of Fig. 3, the washer is displaced somewha downwards, which however is possible due to the elongated hole 38. Thus, it is clear that each cylinder can be taken out in order to check or replace the inserts, without the need for any subsequent realignment of the apparatu Preferably, the alignment takes place by a tool, which is placed against the upper surface 37 and includes guiding surfaces for positioning the washers in their correct positions. When all the washers 39 have been tightened and fixed in place, the cylinders can be introduced in their corresponding bores. Of course, it is possible to introduce the saw blade ^* in their bores without the cylinders being inserted, compare the righthand portion of Fig. 3.

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As mentioned above, the deep frozen fish has the shape of a big block 2 (fig. 8), which first is cut into three loaves 28. The loaves are sliced into longitudinal slices 29, e.g. six slices, and are finally cut into portion bits 30. When the loaves should be sliced by means of the device according to the invention, the frame 11 is inclined a certain angle x, preferably between 0 and 25° in relation to the horizontal .plane h (see fig. 6). The saw blades 12, which are received in the groovfes 24 of the guidings are twisted by means of the guidings 25 into parallel with the horizontal plane (see fig. 4). The loaf of frozen fish is fed over the cutting plan 17, which is horizontal and towards the blade guiding -unit 13 where the saw blades are horizontal and are placed with a certain distance between each saw blade, whereupon the loaf is sliced into the intended number of slices in one and the same operation as appears from fig. 5. For the tension of the saw blades, there is arranged a hand"lever J6 , by means of which the distance between the drums can be adjusted for simul¬ taneous tension of all saw blades. Moreover there are arranged individual saw blade tension units 14 by means of which each saw blade can be separa¬ tely tensioned.

The operation to saw big deep frozen blocks places rather high stresses on the saw blades, which thus must be'very carefully tensioned in order to achieve a fine cutting surface on the product. In order to prevent that the saw teeth of the greatly tensioned saw blades will cut the drums, the drums are provided with a special surface layer 26. The surface layer 26 is shown in details in fig. 7 and comprises shoulders 31, which the saw blades abut, and grooves 32 there between, which receives the saw blades. In order to prevent water gliding or si ular, the grooves 32 are provided with narrow, preferably V-shaped channels 33.

The angle, which the frame must be inclined in order to give a certain thickness of the loaf is calculated by means of the formula:

where x = the inclination of the frame in relation to the cutting plane or horizontal plane h, a = the distance between two adjacent blades, b - the cutting thickness + the thickness of the blade. The angle is preferably adjusted by means of an angle tool such that exactly the same adjustment is achieved for each saw blade.

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By means of the band saw according to the present invention a great number of different slice thicknesses can be achieved by adjusting the in¬ clination angle of the frame or by excluding some of the saw blades. Accor¬ ding to the preferred embodiment, the band saw comprises six saw blades, which makes it possible to produce up to seven slices in a single opera¬ tion. Since often one of the surfaces of the loave28 is uneven, it is suitable to use the sixth or ^' the last saw blade for levelling this uneven- ness.

The advantages of the band saw according to the present invention in relation to previous technics are several.

Compared to previous methods, wherein each slice is ^" cut in a single operation, it is now reqired fewer operating persons and the speed is higher, which entails economic advantages.

Compared to previous band saws, where several band saws are placed in line, the band saw according to the present invention gives a considerable lower investment cost. Moreover, the space required is considerable less and the cleaning time is shorter. Since the band saw according to the presen invention only comprises a common motor, the maintenance is much simpler. Saw spill at only one position makes the collection thereof more simple and furthermore the energy consumption is cosiderable lower.

Above all, the band saw according to the present invention has a very great flexibility. The conversion to a new slice format is quickly and easil made.

The band saw is preferably manufactured in stainless steel, but whatever suitable material can be used. The preferred embodiment described above can be modified in many respects by a skilled person within the scope of the invention..The invention is only limited by the appended patent claims.

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