Technical field of the invention

The present invention relates to a machine for slicing fish fillets, in particular salmon fillets.

Background of the invention

The present invention relates to a machine for slicing fish fillets, in particular salmon fillets. The machine is, more specifically, of the kind described in the beginning of claim 1 .

Known filleting machines of the kind described are usually constructed with a flat cutting table consisting of at least two belt conveyors placed with their conveyor tracks at the same horizontal level. Between the two belt conveyors is inserted a cutting device, which with knives designed to make cuts perpendicular on the belt conveyor s feed direction, cuts through the fish fillets that are placed on the cutting table and which by means of the belt conveyors are fed through the cutting zone of the machine. The transverse cuts are made in a pre-set diagonal angle in relation to horizontal, allowing the fish fillet to be cut into a number of relatively thin slices, which are wider than corresponding to the thickness of the fish fillet. The transverse cuts are made successively with the feed of the fillet through the machine so that the relation between the feed rate of the belt conveyor and the cut frequency of the cutting device will determine the thickness of the fillet slices produced.

Filleting machines of this kind, also known as fillet slicers, are available in many different designs. The machines are especially applied for slicing of salmon and halibut fillets but are of course also applicable for slicing of other meat and cold cuts products. A general problem with the known machines is low operating speed (cut frequency), poor cut quality and an undesired variation in the thickness of the slices. Moreover, the machines are often constructed with a technically complex cutting device, which makes the daily cleaning of the machine laborious and time-consuming. Accessibility to the vital working parts of the machine in connection with continuous maintenance and cleaning of the machine is often insufficient and ill-considered.

An example of a known filleting machine of the above mentioned kind is the Danish utility model DK 2012 00081 U3. The machine described in the utility model specifications is such an example of a machine with a technically complex cutting device, with an angle adjustment mechanism that is practically inaccessibly placed under the machines- cutting table and with cutting parts that are constructed somewhat unstable resulting in poor cut quality. The daily cleaning of the machine is difficult to carry out because of the inaccessible placement of the angle adjustment mechanism.

The objective of the present invention is to remedy the above mentioned shortcomings and inconveniences in known filleting machines. More specifically, the objective is to further develop the kind of filleting machine described here in such a way that the machine can operate at a higher operating frequency, i.e. with higher performance than has previously been possible, that the weaknesses of the knife guidance are eliminated, and that the machine in general will obtain an improved accessibility so that the daily cleaning and maintenance of the machine is facilitated.

Summary of the invention

The objective of the present invention is to remedy the above mentioned shortcomings and inconveniences in known filleting machines. More specifically, the objective is to further develop the kind of filleting machine described here in such a way that the machine can operate at a higher operating frequency, i.e. with higher performance than has previously been possible, that the weaknesses of the knife guidance are eliminated, and that the machine in general will obtain an improved accessibility so that the daily cleaning and maintenance of the machine is facilitated.

The solution according to the invention is a filleting machine, which in a known manner comprises a primarily horizontal conveyor track and, designed to connect with the conveyor track, a cutting device, which primarily consists of a cutting part consisting of a set of lengthwise movable, reversed reciprocating knives and a for these knives in the conveyor track integrated cutting dolly. The cutting part is placed

perpendicular on the conveyor track and comprises means partly to move the knives in the longitudinal reversed reciprocating motion relative to each other, and partly to move both knives down towards and away from the cutting dolly while completing a cut into the fish fillet.

The novelty of the filleting machine, according to invention, is that the cutting device is structured with an above the conveyor track placed angle adjustable supporting frame practically bridging the conveyor track and that on each side of this supporting frame is mounted a linear guide, which serves to control the knives in their motion down towards and away from the cutting dolly. The double-sided guidance of the knives ensures a stable and accurate guidance of the knives and thus an accurate cutting motion down towards and away from the cutting dolly. The accurate cutting motion is essential to the machine s ability to achieve the best possible cut quality with clean cuts of high cut frequency and, at the same time, with a uniform slice thickness as a result.

The structure of the machine with the cutting device in general designed as a bridge across the machine s conveyor track and with guides and cutting parts mounted easily accessible in direct connection to the sides of this bridge means that the daily cleaning of the machine can be carried out swift and efficiently and that the continuous maintenance of the parts of the machine which require special inspection, i.e. especially the cutting parts with the two reversed reciprocating knives, and the angle adjustment mechanism of the support frame can equally be carried out swift and efficiently.

An advantageous embodiment of the filleting machine, according to the invention, is stated in claims 2, 3 and 4, where it is specified that for the motion of the knives down towards and away from the cutting dolly is inserted a separate drive unit in each side of the supporting frame, and that these two drive units are synchronised with each other for parallel guidance of the knives up and down. The drive units could advantageously be of the kind that consists of an electromagnetic linear motor based on an

electromagnetic cylinder. To achieve a compact structure with the best possible machine stability as well as the best possible accessibility in relation to cleaning and maintenance, each drive unit could advantageously made of an electromagnetic linear motor and a linear guide. These two components will then be integrated into a compact assembled unit that as one single machine unit is mounted directly on the supporting frame.

Electromagnetic linear drive units of the kind in question are marketed today as prefabricated standard components. The drive units are

characterised by their ability to operate at a very high motion speed and with high repeatability accuracy, which in turn allows for the cutting motion of the machine to be completed and repeated at high frequency. The solution means that the filleting machine can operate at a substantially higher cut frequency than previously known in slicers of this kind, and thus with a considerably higher production capacity than has previously been possible.

An embodiment, as specified in claim 5, offers a simple and functional solution to the problem of adjusting the machine s cutting dolly to the cutting angle to which the machine s cutting dolly is currently set. The cutting dolly is simply designed as a replaceable unit with the cutting angle adjusted for the required setting. If the cutting angle is changed, which is achieved by angular adjustment of the entire cutting device relative to the horizontal cutting table, the cutting dolly is replaced at the same time in order to maintain a suitable match between the cutting angle of the cutting device and the cutting angle of the cutting dolly. Appropriately, the cutting dolly is inserted in the gap between two belt conveyor sections in the conveyor track and, at the same time, levelled with these so that the belt conveyor sections and the cutting dolly combined form an almost flat, continuous conveyor track for the fish fillet through the cutting zone of the machine. Thereby ensuring that the fish fillet pass through the machine s cutting zone in a in a smooth, continuous motion which is essential to obtaining slices of uniform thickness.

It should be noted that the structure of the machine with the cutting device structured as an angle adjustable bridge placed across the conveyor track makes it possible to design the cutting device so that the angle interval in which the cutting device can be adjusted becomes significant. It is, for example, possible to adjust the cutting device for vertical cut so that the machine, besides normal filleting, can also be used for cutting the fish into portion sizes. In claim 7 is specified a preferred embodiment for the machine s

reciprocating knives. The knives comprise two parallel mounted reversed knives that are removably inserted into holders, which are controlled in linear guides made for that purpose. The holders are driven by a joint driving device designed for generating the reversed reciprocating, back and forth motions of the knives. The knives, the knife holders, the linear guides and the joint driving device is mounted in connection to the two in the sides of the supporting frame mounted linear drive units for guiding of the knives in a parallel guide motion down towards and away from the cutting dolly during the operating process of the machine. The joint driving device can according to the invention advantageously consist of an electromotor equipped with connecting rod and eccentric drive. The connection between this drive and the knives consists of joint rods. The construction is mechanically simple and sturdy and able to operate at a high frequency. Alternatively, the driving device can consist of a separate electromagnetic cylinder directly connected to each knife. The two cylinders are mutually synchronized by a suitable electronic control of the cylinders allowing the knives to have the desired reversed reciprocating motion. The solution is constructively simple, easy to clean and allows for an extremely high operation frequency for the knives.

In claim 10 is specified an embodiment where the machine comprises means for continuous registration of the thickness of the fish fillet and for continuous calculation of an optimal cutting angle in relation to the registered fillet thickness. By other means it is possible to complete an automatic angle adjustment of the supporting frame based on the calculated optimal cutting angle so that the cutting angle can be

continuously adjusted and adapted to the variations of the product which is being cut. Although the automatic angle adjustment is limited to an angle interval determined by the cutting dolly with which the machine is currently mounted, it does, however, allow for a certain optimisation of the filleting so that slices of a desired uniform size can be produced. The angle adjustment of the supporting frame is automatic and continuous via a specially designed adjustment motor. The invention is explained in more detail below in connection with the drawings. Brief description of the figures

Figure 1 shows a filleting machine in a preferred embodiment according to the invention, shown from the side in a schematic illustration;

Figure 2 a linear guide and drive unit with integrated electromagnetic cylinder, shown in side view;

Figure 3 the machine s cutting device comprising two linear guide and drive units and a knife mechanism inserted between said units, shown separately and from above;

Figure 4 an enlarged section marked :ΑΊη figure 1 where the filleting machine s knife frame and associated knife guide unit is shown in detail;

Figure 5 same section as shown in figure 4, here with part of the frame removed to visualise the machine s replaceable cutting dolly;

Figure 6 the knife frame shown separately, seen from the side; and

Figure 7 shows a filleting machine from above, shown in full with associated guide and drive units with electromagnetic cylinders and with the

reciprocating knives inserted between the two guide and drive units.

Detailed description of the invention

In the embodiment pictured in the drawing the filleting machine consists primarily of a frame-shaped housing 1 , a horizontal, flat clamping plate 2, a conveyor track 3 composed of three conveyor band sections 4, 5 and 6 placed end to end and levelled horizontally, a bridge-shaped supporting frame 7 with an angle adjustment mechanism 8 mounted over the conveyor track 3, a cutting device 9 consisting of two guide units 10 and a set of reversed movable, reciprocating knives 1 1 , a replaceable cutting dolly 12 inserted into the conveyor track 3, and two control cabinets 13 and 14 mounted over the housing 1 off-set to the conveyor track 3. The fish fillets that are to be filleted in the machine are placed manually on the first belt conveyor section 4. The fish fillets are indicated with F in figure 1 , and the feed direction through the machine is indicated with arrows P.

The clamping plate 2 is mounted at a distance above the housing 1 using a number of spacers 15, and carries partly the supporting frame 7 with associated angle adjustment mechanism 8, and partly the three belt conveyor sections 4, 5 and 6. The bridge-shaped supporting frame 7 is assembled by two rectangular frame-shaped sides 16 and a number of traversers 17 inserted across between said sides, see figures 6 and 7. The supporting frame is pivoted in two bearing brackets 18 mounted on the clamping plate 2 on each side of the conveyor track 3, and is driven by a joint rod mechanism 19 with associated motor pinion. The joint rod mechanism 19 and the motor pinion comprise the angle adjustment mechanism 8. The motor pinion is not showed in the drawing. With the angle adjustment mechanism 8 it is possible to change the supporting frame s 7 angular position in relation to the horizontal level of the conveyor track, see figure 4.

The filleting machine comprises, as specified in the above, a cutting device 9 composed of the two guide units 10 and a set of reversed movable, reciprocating knives 1 1 . For the cutting device is included the replaceable cutting dolly 12, which is inserted into the conveyor track 3, see figure 5.

The cutting dolly 12 is made of plastic or hard rubber so that the knives are not damaged if they hit the dolly. The cutting dolly is shaped as a moulding, inserted into a corresponding T-not adaptor integrated into the conveyor track 3 in a narrow space between the second and third belt conveyor section 5 and 6, respectively, see figure 5. The two guide units 10 are mounted on the inside of the supporting frame s 7 two rectangular frame-shaped sides 16, see figure 7. Each guide unit 10 consists of a set of hardened parallel guide shafts 20, which are embedded in ball-bearing guide bushes 21 and connected through a traverser 22 in each end of the guide shafts. Between the two guide shafts is inserted an electromagnetic cylinder 23, linked to the traversers 22 via a through-going piston rod 24. On one traverser 22 is mounted a knife mechanism 25, which primarily consists of two closely spaced oblong knives 26, inserted in the respective knife holder 27. The two knife holders are driven by a knife drive 28, which by means of an electromotor and associated piston rod mechanisms (not shown) is designed to drive the two knife blades 26 with fast reciprocating motions back and forth opposite to each other during the cutting of the fish fillet F. The cutting of the fish fillet is carried out simultaneously with the two guide units 10 sliding the set of knives down towards the cutting dolly 12, see figure 5.

The size (length) of the filet slices produced depends on the thickness of the fish fillet and the supporting frame s angle adjustment. By continuously adjusting the frame angle according to the thickness of the fillet, the slices can be cut into suitable uniform sizes. For this task is used equipment for continuous measurement of the fish fillets that are fed into the machine on the first or second belt conveyor section 4 or 5, and for automatically adjustment of the frame angle in relation hereto. The measurement equipment is not shown in the drawing and the adjustment principle and associated equipment will not be explained in detail here.

Other material combinations, other detailed designs, and other constructive solutions for individual components of the machine and accessories are possible within the context of this invention, as are the application of the machine for other products than just fish fillets. For example, as a cold-cut slicer for rolled seasoned meat, salami, etc.