Knife, and slicing machine equipped with same

Abstract

To avoid, on the one hand, that resharpening the knife (3) of a slicing machine (1) changes the behavior of the knife (3) during operation, and on the other hand to achieve very gentle penetration and good slice ejection, the radially outermost area of ​​the knife (3) is produced as a resharpening area (4*) with a very low thickness (D), which is constant in the radial direction.

Description

I. Area of ​​application

[0001] The invention relates to the cutting of a material into slices - in particular slices of precise weight - which should be separated as cleanly as possible. II. Technical background

[0002] The production of such slices or portions from an elastic strand material is relatively easy if this strand material has the same cross-section throughout its length and consists of a homogeneous material that can be cut equally everywhere, such as an industrially produced sausage strand or cheese strand.

[0003] For this purpose, so-called slicers are known, which either by means of a round rotating knife, which can be moved forwards and backwards across the strand, or by means of a sickle-shaped knife, the axis of rotation of which remains stationary during operation and in which the cutting edge is located on the outer circumference of the sickle, Cut one slice at a time from the strand-like material to be cut, while the strand, which is usually exposed, is moved forward continuously or only between the cutting processes.

[0004] However, an irregularly shaped piece of meat such as a grown piece of meat does not have these properties, because each of these irregular pieces of meat has a different shape and, in addition, a cross-section that changes over its length and can also consist of materials of different consistency, hardness and elasticity, for example the fat content, the pure muscle meat and / or the surrounding silver skin.

[0005] For the purposes of the present invention, the material to be cut is referred to as a piece of meat, without limiting the invention to meat as the material to be cut, so that it can also be irregularly and undefined shaped pieces made of another material.

[0006] In this context, it is already known to first deform such a piece of meat in such a way that it has a defined, known cross-section - in particular at least at the end at which the next slice is cut off, if slicing is carried out thereafter, at least at the time of cutting off the slice - preferably over the entire length.

[0007] Then a relationship can be established between the adjustable thickness of the disc and the weight of the disc via its specific weight, which is usually known or can be estimated.

[0008] Regardless of this, the cutting quality - for example a fray-free cutting edge of the disc, a consistent disc thickness across its entire surface, etc. - is all the better the less pressure the knife uses to penetrate the material being cut, the less resistance the material being cut offers to the knife and, in this context, the more the cut is a pulling cut, i.e. the greater the pulling factor.

[0009] The tensile factor is understood to be the relationship between the penetration speed perpendicular to the cutting edge at the penetration point and the peripheral speed of the knife along the knife edge, particularly when the cutting edge first comes into contact with the material to be cut.

[0010] In addition to the cutting quality, it is also very important that the cut slice is placed in the correct position and without any creases.

[0011] WO 2015 / 059016 A1, which represents the closest prior art, discloses a knife according to the preamble of claim 1.

[0012] Furthermore, reference is made to DE 10 2016 005 443 A1, US 2013 / 291698 A1 and DE 10 2012 007 290 A1. III. Description of the invention a) Technical task

[0013] It is therefore the object of the invention to provide a knife and a slicing machine equipped therewith and an operating method therefor, with which an optimal cutting result and correct placement of the separated slice is achieved, as independently as possible of the consistency of the material to be cut and in particular of the differences in consistency within the material to be cut. b) Solution to the task

[0014] This object is achieved by the features of claims 1 and 9. Advantageous embodiments emerge from the subclaims.

[0015] A generic, rotatable or rotating knife is usually plate-shaped or slightly bowl-shaped and has on its peripheral edge - usually viewed in the axial direction, i.e. on the main plane of the knife - a curved peripheral edge which is at least partially designed as a cutting edge, i.e. viewed in the radial cross-section tapers outwards at an acute cutting angle which is usually greater than 20°.

[0016] To create this cutting edge, the knife is usually sharpened on only one side, which is defined here as the back. From the knife plane, defined by the cutting edge, this grinding surface, which is part of the back, rises radially inward at an acute cutting angle.

[0017] In a state-of-the-art rotatable knife, this grinding surface is usually followed radially inwards by a connecting surface which is also at an acute angle to the knife plane, but which is smaller than the cutting angle.

[0018] According to the invention, however, a regrinding area of ​​the blade is connected radially inward to this ground surface on the back of the blade, forming a connecting surface. The blade has the same thickness across its entire radial extent. This connecting surface thus runs parallel to the blade plane.

[0019] The regrinding area extends in the circumferential direction, preferably along the entire length of the cutting edge.

[0020] As a result, when the ground surface is regrinded - provided this is done at the same cutting angle that the ground surface had from the beginning to the knife plane - the thickness of the knife in the area of ​​the ground surface and the regrinding area does not change and thus also the radial extent of the ground surface does not change, so that over the entire regrinding area and thus regardless of the state of wear, the knife always has the same parameters and relationships with regard to cutting angle, radial extent of the ground surface, thickness of the knife, in particular at the transition between the ground surface and the connecting surface adjoining it radially inwards.

[0021] Thus, the regrinding area is arranged radially between the grinding surface and a further connecting surface, and in particular directly borders on at least one of them, in particular both of them.

[0022] The same or constant thickness is understood to mean a thickness with deviations that are unavoidable during the manufacturing process of the knife, namely that the thickness in the regrinding area differs by less than 0.5 mm, better by less than 0.3 mm, better by less than 0.2 mm, better by less than 0.1 mm between the largest and smallest thickness of the knife in this regrinding area.

[0023] These permissible deviations are particularly small because in the regrinding area the thickness of the knife should only be a maximum of 2 mm, better a maximum of 1.5 mm, better a maximum of 1.1 mm.

[0024] The radial extension of the regrinding area is a maximum of 20 mm, better only a maximum of 15 mm, better only a maximum of 11 mm.

[0025] The specified thickness of the knife in the regrinding area is sufficient for sufficient stability of the knife in the regrinding area for almost all cutting materials in the food sector.

[0026] If the knife is a bowl-shaped, concave knife, the recess on the concave front of the knife preferably begins radially inside the regrinding area, so that the front of the knife is a flat surface in the regrinding area and up to the cutting edge, if necessary.

[0027] Especially with the specified dimensions in the regrinding area, the adhesive forces occurring between the material to be cut and the knife or disc and knife are still so low that a clean cut, i.e. in particular without fraying on the cutting edges of the disc, and a clean storage can be achieved.

[0028] Since the correct placement of the disc depends on whether the disc is always thrown off the knife in the same way, there is a connection surface offset radially inwards from the regrinding area, which in the radial direction preferably runs at an angle to the knife plane and thus increasingly moves away from the knife plane in the axial direction radially inwards and serves as a deflection shoulder, which directs the outer circumference of the cut-off disc arriving there in the axial direction away from the knife plane and is intended to bring about a defined discharge.

[0029] Accordingly, this deflection shoulder also extends circumferentially over the entire length of the cutting edge.

[0030] The deflection shoulder can bridge the distance in the axial direction between the creeping area and a further connecting surface located further inside and axially further away from the blade plane, or can even protrude beyond the radially outer edge of this next connecting surface in the axial direction and form a deflection bead in order to ensure sufficient axial extension of the deflection shoulder.

[0031] The next connection surface can run parallel to the knife plane or be inclined to it, i.e. run radially inwards with increasing distance to the knife plane or can have any other design.

[0032] Preferably, the deflection shoulder, cut in the radial direction, has a larger deflection angle to the knife plane than the ground surface, i.e. than the cutting angle, which is usually already greater than 20°, since the disc is primarily to be deflected in the axial direction by this deflection shoulder and less by the ground surface.

[0033] Of the multiple connection surfaces spaced apart from one another in the radial direction with different distances to the blade plane - regardless of whether the connection surfaces are parallel or oblique to the blade plane - one can be designed as a deflection shoulder as described above.

[0034] The above-described design of the knife can be present both in a sickle-shaped knife, in which the outer circumferential contour of the knife, designed as a cutting edge, increases in the circumferential direction against the direction of rotation of the knife during its operation, and in a knife with a cutting edge that runs in a circular ring, is closed in a ring, or extends only over one segment, i.e. in particular a circular disk-shaped knife.

[0035] In particular, a circular disk-shaped knife can be plate-shaped, i.e. in particular with a flat front side, or bowl-shaped, with a concave recess in the center in the front side of the knife.

[0036] A slicing machine known per se, in which the knife according to the invention can also be used, comprises a cutting unit which has such a knife as described above, wherein, depending on the basic shape of the knife - sickle-shaped or circular disk-shaped cutting edge - the axis of rotation of the knife, i.e. the knife axis, is stationary during operation or must be moved for immersion into the material to be cut.

[0037] Furthermore, there is a product support on which the material to be cut, i.e. the product, is placed and fed to the cutting unit and pushed forward along the product support during slicing, wherein the support surface for the material to be cut is preferably arranged at an angle downwards towards the cutting unit, inclined relative to the horizontal. c) Examples of implementation

[0038] Embodiments of the invention are described in more detail below by way of example. They show: Figure 1a:a slicing machine cut in the longitudinal pressing direction with a sickle knife, Figure 1b: a slicing machine with a circular disc-shaped knife in the same direction of view, Figure 2a: the slicing machine according to Figure 1a viewed in the longitudinal pressing direction from the cutting end of the forming tube, Figure 2b: the slicing machine according to Figure 1b viewed in the longitudinal pressing direction from the cutting end of the forming tube, Figure 3: a radial cut through the sickle blade of the Figures 1a and 2a , Figure 3a: a detailed enlargement of this, Figures 3b, c: Detailed enlargements from Figure 3a with different transitions between the regrinding area and the rest of the knife cross-section.

[0039] The Figures 1a and 2a show cutting machines according to the state of the art, whereby in the front views according to the Figures 2a , bthe inventive design of the knife 3 is already shown, the cross section of which is based on the Figures 3 - 3c will be explained in more detail.

[0040] The slicing machines according to the Figures 1a , b , 2a , b have, on the one hand - in addition to the base frame 13 of the machine - a cutting unit 2, which also includes the rotating knife 3 and a product support 12' directed diagonally downwards towards the knife 3, on which the product P to be sliced, in particular a grown piece of meat, rests and is pushed forwards intermittently downwards for cutting into slices S.

[0041] In this case, the product support 12' is not a simple support surface, but a circumferentially closed forming tube 12, which is open on both sides at the front, and in which the product P is not only pushed forward for cutting by a longitudinal pressing die 14, but can also be pressed in the longitudinal direction by this longitudinal pressing die 14 beforehand, so that the product P receives a cross-section that is uniform over its length by being applied to the inner circumference of the forming tube cavity 15.

[0042] The stop plate 16 can serve as a stop in the longitudinal pressing direction 10 for pressing. It can be adjusted to a specific thickness setting d in the form of a distance in the longitudinal pressing direction 10 from the front end, the cutting end 12a, of the forming tube 12 for cutting the slices S. However, the stop plate 16 can also be used as a longitudinal stop during pressing of the product P by directly applying it to the front end face of the forming tube 12, since the stop plate 16 is sized to completely cover the cross-section of the forming tube cavity 15 at the cutting end 12a.

[0043] The stop plate 16 can either be attached to the base frame 13 and be adjustable in its axial position according to Figure 1a or attached to the knife carrier 2a, as shown in Figure 1b shown.

[0044] This depends on whether the knife 3 is a sickle knife 3 according to Figure 1a , 2aor a circular disc-shaped knife according to Figure 1b , 2b In the sickle-shaped knife 3, the outer peripheral edge, designed as a cutting edge 3a, has an increasing distance from the rotation axis 3' in the direction of travel. At the end of the cutting edge 3a, this greatest distance between the cutting edge 3a and the rotation axis 3' is so much greater than the smallest distance between the rotation axis 3' and the part of the circumference that is not designed as a cutting edge 3a, as the radial extension of the shaped tube cavity 15 or of the product P.

[0045] If the rotation axis or knife axis 3' is arranged close to the forming tube cavity 15, this knife axis 3' does not have to be moved for cutting slices S, in contrast to the Figures 1a , 2a ,in which the circular disk-shaped knife 3 only comes out of the overlap with the forming tube cavity 15 by the entire knife 3 including the knife axis 3' being moved in an oscillating manner in the penetration direction 9 towards the forming tube 12 until the forming tube cavity 15 is completely within the flight circle as well as the real knife 3.

[0046] The latter is particularly important if the knife is shaped like a circular segment instead of a circular disk, in which the cutting edge 3a, which is concentric to the knife axis 3', extends only over part of the circumference.

[0047] In the Figures 1a , b and 2a , ba slicing machine 1 with two parallel adjacent forming tube cavities 15, here formed in a single forming tube 12, is shown, wherein the knife 3 cuts off a slice S from each of the two products P located in the two forming tube cavities 15 during a severing process, in which it has a correspondingly large diameter or flight circle.

[0048] Accordingly, in Figure 1a In the solution with a sickle-shaped knife 3, this is fastened with its knife axis 3', which in this case also runs in the longitudinal pressing direction 10, to a knife carrier 2a of the cutting unit 2, which is fixedly fastened to the base frame 13.

[0049] In contrast, the Figure 1bwith a circular disk-shaped knife 3 or a circular segment-shaped knife 3, the knife carrier 2a, in which the knife axis 3' of the knife 3 is mounted, can be moved in an oscillating manner in a first transverse direction 11.1 to the longitudinal pressing direction 10 relative to the base frame 13 of the slicing machine 1 and can be driven accordingly.

[0050] The stop plate 16 is also attached to the knife carrier 2a, since it is intended to move together with the knife 3 in an oscillating manner in the first transverse direction 11.1, the penetration direction 9, which in this case runs perpendicular to the cutting edge tangent 8.

[0051] The inventive design of the knife 3 is shown in the Figures 3 - 3c better visible, which represent a section through the knife 3 in a radial plane to the knife axis 3': Figure 3shows a sickle-shaped knife 3 in a radial section passing through the knife axis 3'. However, the area relevant to the present invention near the cutting edge 3a is the same in this sectional view for a sickle-shaped and a circular disk-shaped or circular segment-shaped knife, as enlarged in Figure 3a shown, of which Figure 3b again represents an enlargement near the cutting edge 3a during the cutting of a disc S.

[0052] However, the simplest embodiment according to the invention is shown in the sectional view of the Figure 3cvisible: The plate-shaped knife 3 has a cutting edge 3a in the form of a sharply ground outer peripheral edge, whereby the grinding takes place only from one side: Therefore, the cutting edge 3a is formed by the flat knife front side 3.1 in the radially outermost area, which thus also lies in the knife plane 3", on the one hand, and the ground surface 4, which is inclined thereto, on the other hand, which runs along the circumference and preferably takes up the same cutting angle α with respect to the knife plane 3" everywhere along the circumference and, when viewed from above, i.e. in the direction of the knife axis 3', also has the same width, as best seen in the Figures 2a , b to recognize.

[0053] The radially inner end of the grinding surface 4, which is higher than the knife plane 3", is adjoined by a connecting surface 5 which extends radially further inwards over a so-called regrinding area 4*.

[0054] The essential point, however, is that this first connection surface runs parallel to the front side 3.1 of the knife, i.e. the knife 3 has the same thickness D everywhere in the radial direction along the regrinding area 4*, both in the radial direction and in the circumferential direction within this regrinding area 4*.

[0055] This has the advantage that when regrinding the knife 3 - whereby the abrasive is always applied to the grinding surface 4 over its entire radial extent, and by material removal this ship surface 4 is moved further radially inwards in the direction of the knife axis 3' with a constant cutting angle α - the knife 3 in its outermost area, the regrinding area 4*, retains the same thickness D over the entire duration of its use, because it is regrinded to a maximum up to the radially inner end of the regrinding area 4*.

[0056] Due to the small thickness D in the regrinding area described above, it is obvious that the radial extension of the regrinding area 4* must not be chosen to be too large in relation to this, in order not to impair the stability of the knife in its radially outer area.

[0057] Radially from the connection surface 5 - which is an annular or partially annular surface - another connection surface 5.1 is arranged, which in this case again runs parallel to the knife plane 3", i.e. usually also to the front side 3.1 of the knife - but maintains a greater axial distance from this than the connection surface 5, which is located in the regrinding area 4*.

[0058] The axial height difference between them is overcome by a deflection shoulder 6", which is at a deflection angle β to the knife plane 3", progressively in the radial direction.

[0059] This deflection shoulder 6" serves to ensure that the disc S separated from the cutting edge 3a - as better described in Figure 3b to recognize - is not only deflected by the ground surface 4 alone from the knife plane 3" and is slightly redirected in the axial direction 10, but is supported in this by the deflection shoulder 6", which at least with its upper edge also rests on the already separated disc S and redirects it further in the axial direction 10, in the direction of the knife axis 3'.

[0060] The more defined the guidance of the partially separated disc S is away from the cutting point, the more correctly, i.e. in the correct position and without creases, the disc S is dropped onto the intended impact point, which is usually located on a discharge conveyor or in a collecting tray.

[0061] For this purpose, the deflection shoulder 6" can also be designed to be axially longer than the axial difference between the two adjoining connection surfaces 5 and 5.1 would allow with an unchanged deflection angle β, in that the deflection surface 6" extends in the axial direction even beyond the radially outer edge of the radially inwardly adjoining next connection surface 5.1 and forms a deflection bead 6 which runs parallel and concentrically to the cutting edge 3a along its entire extent, as a rule.

[0062] How Figure 3a shows, in this way further connection surfaces 5.1, 5.2, 5.3 can be connected radially inwards to the outermost connection surface 5, which defines the regrinding area 4*.

[0063] The further connection surfaces from 5.1 onwards can run parallel to the knife plane 3" or be inclined towards it, i.e. radially inwards towards the knife axis 3' with increasing distance to the knife plane 3".

[0064] Furthermore, the 6" deflection shoulder between the individual connection surfaces does not have to be designed as a deflection bead.

[0065] As especially the Figures 3b and 3c show, the deflection angle β is generally larger than the cutting angle α.

[0066] Furthermore, Figure 3a , that the knife 3 can also have a concave depression 7 on its front side 3.1 and can thus be a bowl-shaped knife, wherein the depression 7, viewed radially from the outside to the inside, preferably begins further inward from the radially inner end of the regrinding area 4*, in this case at the connecting surface 5.2, in order to prevent the thickness of the knife 3 from falling below a predetermined knife thickness in any radial area LIST OF REFERENCE SYMBOLS

[0067] 1 Slicing machine 2 Cutting unit 2a Blade carrier 3 Blade 3' Blade axis, rotation axis 3" Blade plane 3.1 Front 3.2 Rear 3a Cutting edge 4 Grinding surface 4*Regrinding area 5.1, 5.2 Connection surface 6 Deflector bead 6" Deflector shoulder 7 Recess 8 Cutting edge tangent 9 Penetration direction 10 Longitudinal pressing direction, axial direction 11.1, 11.2 Transverse direction 12 Forming tube 12a Cutting end 12' Product support 13 Base frame 14 Longitudinal pressing ram 15 Forming tube cavity 16 Stop plate α Cutting angle β Deflector angle d Thickness, thickness adjustment (slice) DD Thickness (regrinding area) P Product, material to be cut S Slice

Claims

1. Rotatable, plate-shaped or dish-shaped blade (3) with a front side (3.1) and a back side (3.2), suitable for use in a slicing machine (1), with - a curved peripheral edge formed as a cutting edge (3a) defining a blade plane (3"), wherein - on the rear side of the blade (3.2), the cutting edge (3a) is adjoined by a grinded surface (4) which is inclined obliquely to the blade plane (3"), extends radially inwards and is at an acute cutting angle (α) to the blade plane (3"), - wherein the radial inner end of the grinding surface (4) lying higher with respect to the blade plane (3") is adjoined by a first connection surface (5), which extends radially further inwards beyond a regrinding area (4*) of the blade (3), which on the rear side of the blade (3.2) adjoins the grinding surface (4) radially to the inside, and which runs parallel to the front side (3.1) of the blade (3), - wherein over the entire radial extension of the regrinding area (4*), the blade (3) has the same thickness (D), - wherein a same thickness (D) means that the thickness (D) in the corresponding area differs by less than 0.5 mm between the greatest and the smallest thickness (D), characterized in that - radially of the first connection surface, a further connection surface (5.1) is positioned which from the blade plane (3") keeps a larger axial distance than the first connection surface (5), - at least the axial distance therebetween is bridged by a deflector shoulder (6") of the rear side (3.2), which is inclined obliquely to the blade plane (3"), and - the regrinding area (4*) is arranged radially between the grinding surface (4) and the deflector shoulder (6").

2. Blade according to one of the preceding claims, characterized in that - the regrinding area directly adjoins at least one of the grinded surface (4) and the deflector shoulder (6"), in particular both of them.

3. Blade according to one of the preceding claims, characterized in that the deflector shoulder (6") projects further beyond the blade plane (3") transversely to the blade plane (3") than the next connecting face (5) radially inside the deflector shoulder (6").

4. Blade according to one of the preceding claims, characterized in that the deflector shoulder (6") has a larger deflection angle (β) in radial direction to the blade plane (3") than the grinded surface (4).

5. Blade according to one of the previous claims, characterized in that an equal thickness (D) means that the thickness (D) in the corresponding area differs by less than 0.3 mm, better by less than 0.2 mm, better by less than 0.1 mm between the greatest and the smallest thickness (D) in this area, calculated from the smallest thickness.

6. Blade according to one of the previous claims, characterized in that the cutting edge (3a) - is a closed cutting edge running around in the shape of a circular ring of a blade (3), in particular a circular disc-shaped blade (3), the convex outer side of a dish-shaped, circular disc-shaped blade (3) being referred to as the rear side (3.2) of the blade (3) or - is a finite cutting edge (3a) in the shape of a circular-segment disc or sickle.

7. Blade according to one of the preceding claims, characterized in that in the case of a blade (3) with a finite, curved cutting edge and a blade axis (3') which is stationary during operation, the shape of the cutting edge (3a) is designed in such a way that, when the blade (3) dips into the product (P) to be cut, the cutting edge contacts the product with a tensile factor of at least 1:15.

8. Blade according to one of the preceding claims, characterized in that - the thickness (D) of the blade (3) in the regrinding area (4*) is max. 2 mm, better max. 1.5 mm, better max. 1.1 mm, - the radial extension of the regrinding area (4*) is max. 20 mm, better max. 15 mm, better max. 11 mm.

9. Slicing machine (1) with - a cutting unit (2) with a rotatable blade (3), - a product support (12') for placing a product (P) on top, characterized in that the blade (3) is embodied according to one of the previous requirements.

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