WO1999052375A1

WO1999052375A1 - An apparatus for removing fish bones

Info

Publication number: WO1999052375A1
Application number: PCT/DK1999/000188
Authority: WO
Inventors: Kaj Olesen
Original assignee: Kaj Olesen Patent Invest Aps
Priority date: 1998-04-01
Filing date: 1999-03-30
Publication date: 1999-10-21
Also published as: NO20000239D0; NO20000239L; AU3025699A

Abstract

The apparatus is in particular intended for removal of nerve bones from a split and/or filleted fish (7) and comprises a fish bone extracting unit (1) with a driven, rotatable member (2) carrying bone engaging means (3), and a counter-pressure element (4) close to the rotatable member (2) for cooperation with the bone engaging means (3). The bone extracting unit (1) is movably and partially relievedly suspended above a conveyor (5) for conveying fish (7).

Description

AN APPARATUS FOR REMOVING FISH BONES

The present invention relates to an apparatus for removing fish bones, in particular for removal of nerve bones from a split and/or filleted fish, comprising a fish bone extracting unit with a driven, rotatable member carrying or guiding bone engaging means, and a counter-pressure element close to the rotatable member for cooperation with the bone engaging means. WO 92/12641, which corresponds to EP-B-0567515 , SE-B-467904, SE-A-9100163 -6 and NO-A-93.2591 , discloses a handheld apparatus for removing fish bones, comprising a rotatable element with cogs or ridges and a resilient counter-pressure element, by means of which fish bones may be pinched in an adjustable gap between the rotatable element and the counter-pressure element and be extracted from the fish by the rotation of the rotatable element . During the passage of the bone between the rotatable element and the counter-pressure element the latter will yield by virtue of its resilience to let the bone pass. The resilience of the counter-pressure element is so adapted that the bone will be clamped with a force sufficient for the bone to be entrained by the rotatable element. The resilience of the counter-pressure element is provided by resilience of the material from which the element is made, by a resilient insert between the counter-pressure element and the surface, on which it is mounted, or by the counter-pressure element being pivotally mounted and forced by a spring towards a position of rest. Adjustability of the resilience is neither provided for nor described. The radially directed surfaces of the cogs may be smooth or provided with embossments to improve the grip on the bones and to prevent the bones from being severed against the counter-pressure element . It is suggested to suspend the manually operated apparatus from a balancing block in order to avoid undue strain on the user. It is further suggested that it would be possible to use the invention in a machine in which fish pieces pass beneath a stationary device for drawing up the bones from said fish pieces. In spite of what is said in WO 92/12641, a functional device or apparatus has not been provided thereby. This appears from WO 94/10848, SE-A-9501034-4 and WO 97/18717.

WO 94/10848 discloses a number of drawbacks in the apparatus disclosed in WO 92/12641 and further discloses further a handheld apparatus, by use of which these drawbacks should be avoided. The apparatus dis- closed comprises a rotatable element with recesses and a counter-pressure element which is resiliently mounted by means of O-rings (with no possibility of adjustment) . The recesses in the rotatable element have edges with a radius of curvature of 0.1 mm to prevent the bones from being cut off instead off being pulled out during use .

SE-A-9501034-4 discloses another invention by the inventor of WO 92/12641. It is stated in the opening part of the description that it is well known that machines for pulling pin-bones out of fish work poorly. These known machines (which include the one disclosed in WO 92/12641) are said to comprise a rotatable element and a fixed counter-pressure element, whereby a bone to be pulled out is subjected to squeezing and frictional forces and is at the same time bent over a sharp edge which breaks the bone. Therefore, a quite new design of a bone pulling device is provided having fork-shaped elements, which are pressed over cylindrical elements and turned around while pinching the bone. The possibility of building in the device in a fillet- ing machine is mentioned without further description.

WO 97/18717 refers to NO 93.2591, which is so to say the Norwegian part of WO 92/12641, and states that the device disclosed "has proven not to be serviceable in practice, since the fish bones either have a tendency to stop the drum (the rotatable element) by becoming tightly wedged, or they do not get gripped tightly enough by the drum so that they "slip" back into the meat". The publication further discloses a device for pulling bones from fish comprising two coaxial, perforated drums rotating at different speed. The device disclosed is driven and used manually. However, it is said that the device may be used in a production line for fish products and placed in connec- tion with a conveyor belt, where the fillets pass under the device so that the device rolls over the fillets and removes bones therefrom.

WO 98/05215 refers to SE-B-500531, which corresponds to WO 94/10848, and states that the manually operated device disclosed therein does not function very well, assumably due to three factors which are therefore sought to be solved. This is done by attaching fish fillets to a freezing drum and passing the fish fillets under a stationarily mounted device according to WO 94/10848.

In addition to the above publications, the somewhat older DE-A-25 41 427 discloses an apparatus for automatic removal of nerve bones from fish. The apparatus has a bone extracting device placed between two conveyor belts for supplying and removing fish, respectively. The device has a hollow, rotating drum, in the jacket of which rhumb-shaped openings are provided, through which the bones may enter. In the drum stationary, joggled discs are provided, said discs serving as clamping discs and retaining the bones such that they may be extracted, when the fish is forced to pass . A holding down member for holding down the fish towards the apparatus is provided above the device. It is said without further explanation that it will be possible to use a continuous conveyor belt and to arrange the bone extracting device thereabove.

Generally, manually operated apparatuses have in practice turned out to have a limited capacity, which makes them less suited in an industrial production. It has thus been proposed several times to place a fish bone extracting device above a conveyor, but only the inventor of WO 98/05215 has apparently been able to describe such an apparatus. This apparatus, which is provided with a freezing drum is, however, somewhat complicated.

The object of the present invention is to provide an apparatus having a capacity so big that it is suited for industrial production, and by means of which apparatus at least some of the drawbacks of the prior art apparatuses are avoided.

This object is met in that the bone extracting unit is movably and partially relievedly suspended above a conveyor for conveying fish. In this way the apparatus can extract bones automatically from fish conveyed on the conveyor, the position of the bone extracting unit adapting automatically to the surface contour of the fish.

The rotatable member and the counter-pressure element are adjustably biased against one another. This is a fairly important feature, because the proper spring load, which with a big degree of safety gives the desired result, depends on the condition of the fish: whether it has been treated, for instance smoked or whether it is fresh, for how long ago was it caught, etc. Upstream of the travelling direction of the conveyor the fish bone extracting unit is preferably provided with preferably vertically adjustable control means for abutting a fish which is conveyed on the conveyor towards the fish bone extracting unit. In this way the adaptation of the positioning of the bone extracting unit relative to the surface contour of the fish is facilitated.

The rotatable member is preferably a roller, in which the bone engaging means are ribs on the roller preferably extending in the axial direction thereof, and the cross section of the roller with the ribs has preferably the shape of a circular saw blade, the teeth of which extend backwards relative to the direction of rotation. Such a roller has proved well suited for accurately pinching nerve bones without tearing the meat of the fish. Furthermore, each of the ribs has preferably a top surface constituting a part of a cylinder surface and the top surface is provided with a flat recess extending along the rib.

The counter-pressure element prefereably extends tangentially along approximately half of the periphery of the roller, a gap of approximately 0.1 mm being preferably provided between the roller and the counter- pressure element.

The ratio between the travelling speed of the conveyor and the peripheral speed of the rotatable member lies within the range of 1:25 to 1:60, preferably in the range of 1:30 to 1:50. The length of a nerve bone is typically between 25 and 60 mm and by adapting the relative speed of the periphery of the rotatable member and the travelling of the conveyor is obtained that the fish is only advanced by approx. 1 mm during the extraction of the bone, which contributes to prevent the meat of the fish from being torn. The rotatable member is preferably a roller, the axis of which is parallel with the fish carrying surface of the conveyor, in which the axis of the roller is oblique relative to the travelling direction of the conveyor. Hereby is obtained that for instance nerve bones, which in a fish extend in a plane oblique relative to the longitudinal direction of a fish, may be extracted in their longitudinal direction such that the meat of the fish is not torn. The oblique position- ing of the roller axis is then preferably adjustable and lockable for adaptation to any actual type of fish.

In such an embodiment, in which the rotatable member is a roller, a nozzle for rinsing water is provided at one end of the roller, tangentially after the counter-pressure element and axially directed along the surface of the roller. In this way it becomes possible to remove extracted bones from the roller. A screen for rinsing water and bones is preferably provided next to the bone extracting unit. In this way the extracted and rinsed bones gather in a specific place, which facilitates the removal thereof.

The conveyor is preferably a belt conveyor, and the fish carrying surface of the belt is preferably provided with small protrusions extending in the travelling direction for engaging the scales of the fish if the fish has not yet been skinned. In this way a safe conveyance of the fish is obtained, also in case of friction with the fish bone extracting unit.

The invention will now be explained in detail in the following by means of an example of an embodiment with reference to the drawing, in which

Fig. 1 shows an apparatus according to the invention, seen from above,

Fig. 2 the apparatus in Fig. 1 seen from the side, the very fish bone extracting unit being cut as shown by the line II -II in Fig. 1, and

Fig. 3 an enlarged detail of the fish bone extracting unit.

Figs 1 and 2 show a fish bone extracting unit 1, which through a chain 16, a lever arm 17 and a gallows

18 is suspended above a belt conveyor 5, on the surface

8 of which split fish 7 are positioned for removal of the nerve bones 40.

The fish bone extracting unit may be moved upwards and downwards to follow the contour of the fish 7 which are to be deboned. The vertical movement of the fish bone extracting unit 1 is controlled by a guide rod 19 fixedly mounted on the unit 1, said guide rod being vertically displaceable in a slide bush 20. Bellows 21 prevent water and other impurities from penetrating into the slide bush.

The fish bone extracting unit 6 is relieved as to weight, as the lever arm 17, which is fastened to the gallows 18 in the point 22, at the end opposite to the securing of the chain 16 carries a displaceable lot 23, by means of which the relief of the load relief of the fish bone extracting unit 1 may be adjusted. Instead of the lot 23, a spring arrangement might be used for load relief. By means of the load relief, the pressure of the bone extracting unit 1 towards the fish 7 is adjusted to between 20 g and 2 kg, preferably between 50 g and 1 kg.

A vertical rod 24 extends downwards from the gallows 18 and carries at its lower end a first adjust- ment rod 26 which is in turn connected with the fish bone extracting unit 1. The two adjustment rods 25, 26 are adjustably and lockably connected with each other, such that the angle of the fish bone extracting unit 1 relative to the travelling direction 9 of the conveyor 5 can be adjusted and maintained. 8

The second guide rod 26 is connected with the fish bone extracting unit 1 by a vertical pin 27 on the fish bone extracting unit 21 which may slide up and down in a hole in the second adjustment rod 26 during the vertical movements of the fish bone extracting unit 1. The fish bone extracting unit 1 comprises a rotatable element in the form of a roller 2 with bone engaging means in the form of ribs 3 and a counter pressure means in the form of an element or a block 4. The roller 2 extends in parallel with the plane of the belt surface 8 (see Fig. 2) and under an angle relative to the travelling direction 9 of the conveyor 5 (see fig. 1) . The block 4 extends in parallel with the roller 2 and surrounds the roller on the half which is substantially downstream relative to the travelling direction 9. The block 4 is by means of screws 28 and springs 13 resiliently clamped towards the roller 2, a gap of approx 0.1 mm being provided between the surface touched by the roller 2 and the surface 39 of the block 4 facing the roller, such that direct contact and subsequent friction between the roller 2 and the block 4 is avoided. Of course the tension in the springs 13 may be adjusted by means of the screws 28 and the block 4 may move away from the roller 2 against the adjusted spring tension to allow passage of a bone 40 during extraction. This possibility of adjustment is important as a too small tension entails that the bones 40 are not pinched sufficiently strongly to be extracted, whereas a too high tension causes the bones to break, whereby parts of the bones will be left in the fish.

In front of or upstream of the roller 2 relative to the travelling direction 9, a guide 29 is provided comprising guide means in the form of curved rods 6 which are individually secured in a guide block 30 which is in turn vertically and adjustably secured to the fish bone extracting unit 1 by means of screws 31.

The roller 2 is driven via a shaft 32 by an electromotor 33.

A nozzle is provided on the fish bone extracting unit 1 for spraying out rinsing water along the roller 2 to remove extracted bones. The nozzle 14 is supplied through a pipe 34 extending up to the gallows 18 and along the gallows to a connection 35 for a supply pipe 36. A vertical screen 15 is arranged next to the fish bone extracting unit .

Fig. 3 shows the design of the roller 2 in detail with ribs 3 and the block 4 seen in cross section. The block 4 has a substantially horizontal underside 37 which extends from an edge 38, from which also the curved surface 39 extends, said surface following the contour of the surface touched by the roller 2.

The roller 2 is cylindrical and has, as mentioned above, ribs 3 having top surfaces 11 positioned in the cylinder case surface touched by the roller 2 during its rotation. In the top surfaces 11 low recesses 12 are provided. During operation, the roller 2 rotates in the travelling direction indicated by the arrow 10.

The nozzle 14 is for illustrative purposes shown in Fig. 3, but it should be understood that in Fig. 1 it is positioned at the end of the roller 2, which is opposite relative to what is shown in Fig. 3.

The design shown of the ribs 3, in which they extend like the teeth of a backwardly rotating circular saw, has proved particularly suited for pinching and extracting nerve bones 40 from a split fish.

The nerve bones 40 in a fish extend partly from outside and towards the middle of the fish, i.e. upwards seen in Fig. 3. Moreover, they extend obliquely relative to the longitudinal direction of the fish, 10 seen in projection on the centre plane of the fish as shown in Fig. 1. The oblique positioning of the fish bone extracting unit 1 and subsequently of the roller 2, which is adjustable by means of two adjustment rods 25, 26, is adjusted in such manner that the roller 2 extends perpendicularly to the nerve bones 40 seen in projection towards the centre plane of the fish (Fig. 1) . Hereby is obtained that the bones 40 are extracted substantially in their longitudinal direction without tearing the surrounding meat.

To further avoid tearing of the meat, the speed of rotation of the roller 2 and the speed of conveyance of the conveyor 5 are adjusted such that the fish 7 is only advanced for instance 1 mm during the extraction of a bone 40. As the nerve bones 40 typically have a length of 30 - 50 mm, it means that the peripheral speed of the roller 2 has to be 30 - 50 times higher than the conveyance speed of the belt 5 or even higher, the oblique positioning of the fish bone extracting unit 1 being considered, or if fish with even longer nerve bones are treated.

To prevent extracted bones from being carried along with the roller 2 and once more drawn into the gap between the roller 2 and the block 4, the nozzle 14 is as mentioned before provided for rinsing bones from the roller 2. The screen 15 ensures that water and bones are not sprayed a long way, but drop down on the conveyor belt surface 8, from where they can be separately collected. Alternatively, the width of the belt 8 may be limited, and a collection groove may be provided under the screen 15.

In a practical embodiment, two fish bone extracting units 1 are provided mirror-symmetrically around the screen 15, such that the right and the left halves of a fish may be treated simultaneously. 11

The surface 8 of the belt is preferably rough, protrusions being provided which extend forwards in the travelling direction 9 in such a manner that they may engage scales of fish, which are deboned in unskinned condition.

It should be understood that though the invention in this context has been described in connection with extraction of nerve bones, it is not limited thereto but may also be used in connection with other types of fish bones.

Claims

12P A T E N T C L A I M S

1. An apparatus for removing fish bones, in particular for removal of nerve bones from a split and/or filleted fish (7) , comprising a fish bone extracting unit (1) with a driven, rotatable member (2) carrying or guiding bone engaging means (3) , and a counter-pressure element (4) close to the rotatable member (2) for cooperation with the bone engaging means (3), c h a r a c t e r i z e d in that the bone extracting unit (1) is movably and partially relievedly suspended above a conveyor (5) for conveying fish (7) .

2. An apparatus according to claim 1, c a r a c t e r i z e d in that the rotatable member (2) and the counter-pressure element (4) are adjustably biased (13) against one another.

3. An apparatus according to claim 1 or 2, c h a r a c t e r i z e d upstream of the travelling direction (9) of the conveyor (5) the fish bone extracting unit (1) is provided with preferably height- adjustable control means (6) for abutting a fish (7) which is conveyed on the conveyor (1) towards the fish bone extracting unit (1) .

4. An apparatus according to any of the preceding claims, c h a r a c t e r i z e d in that the rotatable member is a roller (2) , that the bone engaging means are ribs (3) on the roller which preferably extend in the axial direction thereof, and in that the cross section of the roller with the ribs has the shape of a circular saw blade, the teeth of which extend backwards relative to the direction of rotation (10) .

5. An apparatus according to claim 4, c h a ra c - t e r i z e d in that each of the ribs (3) has a top surface (11) constituting a part of a cylinder surface and that the top surface is provided with a flat recess (12) extending along the rib. 13

6. An apparatus according to claim 4 or 5, c h a r a c t e r i z e d in that the counter-pressure element (4) is a member, which extends tangentially along approximately half of the periphery of the roller (2), a clear of approximately 0.1 mm being preferably provided between the roller and the counter-pressure element.

7. An apparatus according to any of the preceding claims, c h a r a c t e r i z e d in that the ratio between the travelling speed of the conveyor (5) and the peripheral speed of the rotatable member (2) lies within the range of 1:25 to 1:60, preferably in the range of 1:30 to 1:50.

8. An apparatus according to claims 4-7, c h a r- a c t e r i z e d in that the rotatable member is a roller (2) , the axis of which is parallel with the fish carrying surface (8) of the conveyor (5) and that the axis of the roller (2) is oblique relative to the travelling direction (9) of the conveyor.

9. An apparatus according to claim 8, c h a r - a c t e r i z e d in that the oblique positioning of the roller axis is adjustable and lockable.

10. An apparatus according to claims 4 - 9, c h a r a c t e r i z e d in that a nozzle (14) for rinsing water is provided at one end of the roller (2) , tangentially after the counter-pressure element (4) and axially directed along the surface of the roller.

11. An apparatus according to claim 10, c h a r a c t e r i z e d in that a screen (15) for rinsing water and bones is provided next to the bone extracting unit (1) .

12. An apparatus according to any of the preceding claims, c h a r a c t e r i z e d in that the conveyor is a belt conveyor (5) and that the fish carrying surface (8) of the belt is provided with small protru- 14 sions extending in the travelling direction.