EP3747607A1 - Blade, in particular for slicer - Google Patents

Abstract

In order to prevent slices (S) cut off by a slicer (20) from temporarily sticking to the cutting surface (2) of the knife (1) and not coming to the desired position on the base when thrown, the arrangement of one or more - known per se - recesses (5) in the knife back (1.2) facing away from the product caliber (P) proposed in a specific way.

Description

I. Field of application

The invention relates to knives, in particular rotating knives, in particular rotating sickle knives, such as are used above all in slicers for cutting sausage, cheese or other strand-like, elastic food products.

II. Technical background

The problem here is that the thin and very elastic disks temporarily adhere to the back of the knife facing the disk when they are cut off and therefore do not lie flat when they are separated and thrown onto a base, but instead form waves or folds or do not meet the desired target Position on the mat.

To avoid this, it is for example from the EP 2948279 B1 , known to vary the cutting angle of the cutting edge in the circumferential direction of the knife.

The disadvantage of this solution is that it is complex to reproduce this cutting angle, which changes in the circumferential direction, when the knife is regrinded.

III. Presentation of the invention a) Technical task

It is therefore the object of the invention to provide a better solution for preventing slices from sticking to the back of the knife in the form of an improved knife and an operation of this knife in a cutting device.

b) Solution of the task

This object is achieved by the features of claims 1, 13 and 15. Advantageous embodiments emerge from the subclaims.

A cutting device such as a slicer, which cuts strand-like elastic products such as sausage or cheese, so-called caliber, into slices at high speed, usually has a base frame on which a product holder is attached on the one hand, on which the product to be sliced or the product strand is fed to the cutting point is, and on the other hand a rotating knife which successively separates slices from the strand at the cutting point.

It could also be a non-rotating knife, for example one that oscillates in an arcuate movement or a linear movement.

The knife , especially in the slicers used today, is usually a rotating knife, usually a so-called sickle knife, which, however, in contrast to a sickle, does not have the cutting edge on the concave inner contour but on the convex outer contour, which is due to the direction of rotation of the sickle knife The front edge of the knife body is. The cutting edge points in a direction in which this cutting edge extends, the so-called cutting direction a distance which increases continuously, in particular continuously increases, from the axis of rotation, which distance can also have the shape of a geometric spiral around the axis of rotation of the sickle blade.

This has the advantage that the axis of rotation of such a sickle-shaped knife can remain stationary during the cutting operation.

If, on the other hand, the knife is in the shape of a circular disk with an annularly closed, in particular circularly closed, endless cutting edge on the outer circumference, then the axis of rotation of the knife must be moved during cutting operation, in particular moved back and forth in an oscillating manner, in order to cut the slices.

Regardless of this, the known knives are plate-shaped and have a cross-section that is curved outward on one side, the back of the knife, from the cutting plane defined by the cutting edge, while the knife on the front of the knife - the one in the cutting device of the product receptacle, that is, the strand of the product lying on it, facing - as a rule does not protrude beyond the cutting plane.

The cutting edge is formed in cross section through the basic body of the knife by a front cutting surface, which can for example be flat, but, e.g. set back radially from the cutting edge, can also have a front side recess, and a rear cutting surface, the two cutting surfaces extending at an acute-angled cutting angle to each other.

The inner end of the cutting surface facing away from the cutting edge is followed by a pressure surface, which is also part of the curved rear of the knife, but extends to the cutting plane at a pressure angle that is smaller than the cutting angle.

The inner end of the pressure surface facing away from the cutting edge is followed by the mostly flat, remaining knife back of the plate-shaped knife, which in this central area usually has a uniform thickness, apart from the front-side recess that may be present on the knife front.

According to the invention , with such a knife, at least one recess is arranged in the arched back of the knife in order to minimize the sticking of the disc which is in separation to the back of the knife, in particular its pressure surface.

This at least one recess is adapted to the properties of the product and can also depend on various parameters of the cutting device in which this knife is used, for example the material and the roughness of the outside of the knife, the cutting speed and other parameters.

One possibility of adapting to such parameters is to vary the size and / or the shape of the cross-sectional area of the recess lying transversely, in particular perpendicular, to the cutting plane and / or transversely, in particular perpendicular, to the direction of the cutting edge in the direction of the cutting edge, in particular with a sickle-shaped knife.

Another possibility is to vary the position, in particular the radial distance, of the recess from the cutting edge in the direction of the cutting edge.

According to the invention, these two possibilities can also be combined.

The advantage of these solutions is that the cutting angle can be kept constant, not only along the direction of the cutting edge over the entire length of the cutting edge, but also over a number of different products with similar material properties. Above all, this makes regrinding of these knives very much easier, since the depressions to be made specifically only have to be introduced correctly once, namely during the manufacture of the knife, and do not have to be changed with each regrinding process.

This is possible because the width of the cutting surface - depending on the state of wear - is only about 0.5 mm to 2 mm anyway, while the pressure surface in this direction is at least 10 times, possibly even at least 15 times as wide.

Usually the cutting angle is in the order of 30 °, while the pressure angle is only around 20 °.

When designing and positioning the at least one recess, a parameter to be taken into account is the high speed of such knives in so-called slicers, which is at least 500 revolutions per minute, which in the case of a sickle-shaped knife with a maximum radius of, for example, 50 cm, a very considerable penetration speed of the cutting edge causes in the product.

The at least one recess is preferably a hollow groove, which extends with its main direction of extent, ie primarily, along the direction of the cutting edge, but preferably at a distance therefrom. The bottom of the fillet preferably has a uniform curvature transversely to its main extent, so that the fillet can be produced in a simple manner by grinding with a round grinding disk.

This is because regardless of the design of the at least one depression in the plan view of this depression, it is generally located in the printing area and in particular only in the printing area.

In exceptional cases it cannot be located completely within the printing area, but can also be located from there in the adjoining, that is, extend into the area of the rear of the knife facing away from the cutting edge.

However, the recess extends in the direction of the cutting edge preferably at most to the transition from the pressure surface to the cutting surface, that is to say the rear cutting surface which is formed on the rear of the knife. Thus, the recess does not change when the cutting surface is regrinded, especially if there is a distance between the cutting surface and the recess of at least 1 mm, better at least 2 mm, when the knife is new.

Depending on the elasticity of the disc that is being separated or the disc that has already been completely severed, it will not adhere to the back of the knife over the entire surface due to the depression, but rather still adhere to the pressure surface in the areas away from the depression, but due to the high rotational speed this will still be sufficient Pressure effect take place by means of the pressure surface on the disc in the direction away from the cutting plane.

A contact of the disc against the bottom or the flanks of the recess, as could possibly still occur at very low movement speeds, in particular rotational speeds, of the knife, is therefore not possible.

In one embodiment, the at least one recess, in particular in the form of a groove, can also extend only along part of the extension of the cutting edge parallel to it, with a finite cutting edge preferably not having any recess in the starting area and end area along the extension of the cutting edge is.

The size, in particular the width measured transversely to the direction of the cutting edge, and / or the shape viewed in the plan view of the cutting plane and / or the cross-sectional shape and / or the radial position of the recess relative to the axis of rotation in the direction of the cutting edge can be constant, in particular with circular disc-shaped knives.

With a finite cutting edge, that is to say in particular with sickle-shaped knives, these parameters can change along the direction of the cutting edge, in particular increase or decrease continuously along the direction.

If several depressions are arranged one behind the other in the direction of the cutting edge, they can each be of identical design, in particular in the case of a circular disk-shaped knife. In the case of a finite cutting edge such as a sickle knife, on the other hand, the depressions are preferably designed differently, with design parameters of the depressions preferably increasing or decreasing continuously in a direction along the direction of the cutting edge.

By varying the parameters of the one or more depressions - especially with a non-circular disc-shaped knife - the changing angle of entry of the cutting edge into the product and the changing cutting speed, i.e. the relative speed between knife and product at a point on the cutting edge, which is in the product, consideration must be given.

As a rule, the thickness of the basic body of the knife is a maximum of 15 mm, better a maximum of 12 mm, better a maximum of 8 mm.

Starting in particular from this value, the maximum depth of the depression should be no more than 2 mm, better no more than 1 mm, better no more than 0.5 mm, better no more than 0.3 mm.

In relation to the thickness of the knife at the radially inner end of the pressure surface facing away from the cutting edge, the depth of the depression should be a maximum of 20%, better a maximum of 10%, better a maximum of 5%.

These absolute values or relative values have proven to be particularly suitable in practice.

The clearance angle with which, in a cross-section through the recess, its flank facing the cutting edge runs to the back of the knife directly adjacent to the edge of the recess, can - especially in the case of circular disc-shaped knives - be constant along the direction of the cutting edge for a single recess or for each Well, and in the case of several wells, the number of wells must be the same.

In the case of a finite cutting edge, such as, in particular, in the case of a sickle knife, this value can steadily increase or steadily decrease along the direction of the cutting edge, preferably continuously.

In the case of a sickle-shaped knife, this in turn enables an adaptation to the different geometric parameters depending on the rotational position of the sickle-shaped knife to the strand of the product.

When viewed from above on the pressure surface, the at least one depression should reach up to the cutting surface over at least part of its extension in order to avoid a pressure surface running continuously along the cutting surface in the direction of the cutting edge, which would encourage the disc to start sticking.

The width of the recess, measured perpendicular to the cutting edge along the back of the knife, should be at least 30%, better at least 50%, better at least 70% of the width of the printing surface in this direction, in order to achieve a sufficient effect.

With regard to the use of such a cutting knife in a slicer, the desired effect in the inventive design of the depressions in the rear of the knife occurs to a sufficient extent, preferably when the speed of the cutting blade is at least 500 rpm, better at least 700 rpm, better at least 1000 rpm, better at least 1200 rpm.

In this case, however, an upper limit of at most 5000 rpm, better at most 3000 rpm, better at most 2500 rpm, of the cutting knife should not be exceeded.

c) Embodiments

Figur 1a:

einen bekannten Slicer in der Seitenansicht,

Figur 1b, c:

das bekannte plattenförmige Messer des Slicers in der Aufsicht und im Teilschnitt,

Figur 2:

das erfindungsgemäße Messer in analogem Teilschnitt gemäß Figur 1c,

Figuren 3a - c:

das erfindungsgemäße Messer in der Aufsicht in mehreren Ausführungsformen.

Embodiments according to the invention are described in more detail below by way of example. Show it:

Figure 1a:

a well-known slicer in side view,

Figure 1b, c:

the known plate-shaped knife of the slicer in top view and in partial section,

Figure 2:

the knife according to the invention in an analogous partial section according to Figure 1c ,

Figures 3a - c:

the knife according to the invention in plan view in several embodiments.

Figure 1a shows a conventional slicer 20 as a cutting device for cutting a strand-like product P into slices S.

The rope-like product P, the so-called caliber P, rests on a product support 22, for example a sliding surface or a roller conveyor, which is usually inclined downwardly towards the knife 1, and is pushed from the rear end by a slide 24 resting there, usually in steps, pushed forward, but also prevented from sliding forward too quickly by means of retaining claws 25.

At the front, lower end of the product receptacle 22 there is a so-called cutting goggle 23 with at least one product passage through which the front end of the caliber P is pushed, with the Figure 1a several caliber P and product passages in the cutting glasses 23 can be located one behind the other.

The overhang of the caliber P protruding from the cutting goggles 23 is cut off immediately in front of the cutting face of the cutting goggles 23 facing away from the slide 24 by a rotating, sickle-shaped knife 1 along a cutting plane 1 ″ as a disk S with a thickness D and mostly falls onto one conveyor not shown.

How better in Figure 1c As can be seen, the base body 1b of the plate-shaped knife 1 tapers to a point along its outer circumference when viewed in cross-section, the acute-angled cutting edge 1a being formed by the rear cutting surface 2 present on the knife rear 1.2 and the front cutting surface 3 present on the knife front 1.1 becomes.

It can be seen that in the otherwise flat knife front side 1.1 a front side recess 6 can be present, which can extend with its outer flank 6a to the cutting edge 1a, so that then the cutting edge 1a from the rear cutting surface 2 and the outer Flank 6a of the recess 6 can be formed.

Only those - in use according to Figure 1a The knife rear side 1.2 facing the disc S to be separated thus bulges beyond the cutting plane 1 ″, but not the knife front side 1.1.

The cutting edge 1a running around in a plane defines a cutting plane 1 ". The rear cutting surface 2 is inclined to the cutting plane 1" at a cutting angle δ. On the side of the rear cutting surface 2 facing away from the cutting edge 1 a, this is adjoined by the flatter surface than the cutting surface 2 Cutting plane 1 ″ at a pressure angle β to cutting plane 1 ″, which is intended to push the severed disk S away from cutting plane 1 ″.

In Figure 1b The shape of the knife 1 viewed in the direction of the axis of rotation 1 'can be seen, the cutting edge 1a of which extends over approximately 3/4 of the circumference of the knife in one of the two circumferential directions 9, the so-called cutting direction 9.1, continuously increasing in its distance from the axis of rotation 1', as a result, when the knife 1 rotates about the axis of rotation 1 ', it increasingly penetrates the product and this is completely severed at a corresponding distance between the axis of rotation 1' and the product passage in the cutting glasses 23.

Figure 2 shows in an analog representation according to FIG Figure 1c the inventive design of the knife 1:
In this case, a recess 5 is arranged in the pressure surface 4, the cross-sectional contour of which - in a section perpendicular to the direction of the cutting edge 1a, the viewing direction of the Figure 2 - represents a segment of a circle, so the bottom of the recess 5 represents part of an arc with the center 7, mainly because the recess 5 can then be produced with a round, rotating grinding wheel 8 indicated by dashed lines, the axis of rotation of which is preferably in the viewing direction the Figure 2 , ie the direction 9 of the cutting edge 1a runs through the in Figure 2 The center 7 of the circular arc of the recess 5 is shown.

According to the Figure 2 as well as the Figures 3a - c the recess 5 extends up to the transition between the pressure surface 4 and the rear cutting surface 2, but could also be arranged at a distance from this.

On the end facing away from the rear cutting surface 2, the recess 5 does not reach the end of the pressure surface 4 there, but rather its extension in this direction is approximately 60% of the width B measured in this direction of the pressure surface 4, but is about 10-15 times the width b of the rear cutting surface 2 in this direction.

The clearance angle a at which the flanks of the recess 5, in particular the flank pointing in the direction of the cutting edge 1a, open into the surrounding pressure surface 4 is a maximum of 3 °, better a maximum of 2 °, and the transition can also be rounded. This prevents damage to the cut surface on the product P, in particular on the disc S.

The design of the recess 5 in the plan view of the knife rear side 1.2, in particular along the circumferential direction 9 of the knife 1, is shown in FIG Figures 3a - c but different:
With the design according to Figure 3a the width BV of the recess 5, measured along the pressure surface 4 and perpendicular to the cutting edge 1a, remains constant in the circumferential direction 9, and in particular only increases at the beginning and decreases again at the end, whereby the radially outer edge of the recess 5 also increases or decreases with increasing or decreasing width BV always runs at the same distance 12 from the cutting edge 1a, and in particular up to the transition, usually a kink, between the pressure surface 4 and the rear cutting surface 2 or, in contrast, maintains a distance 12, as in the upper region of the Figure 3a shown.

The starting area and end area of the pressure surface 4 in the circumferential direction 9, that is to say in each case a maximum of 15%, better a maximum of 10% of the extension in the circumferential direction 9, preferably has no depression 5.

With the design according to Figure 3b the recess 5 has an increasing width BV, in particular a continuously increasing width BV, in the cutting direction 9.1, that is to say the circumferential direction with increasing distance of the cutting edge 1a from the axis of rotation 1 '.

In this design, the recess 5 also extends over the entire circumferential length parallel to the cutting edge 1a, but this is not a condition for a design with a width BV increasing in the circumferential direction.

With the design according to Figure 3c a plurality of depressions 5 are arranged one behind the other at a distance from one another in the circumferential direction 9, which in this case are of identical design, but this is not a requirement for this design with several depressions 5 arranged one behind the other.

In particular, these depressions 5 have, at least in their central region in the circumferential direction 9, a constant width BV measured perpendicular to the cutting edge 1a along the pressure surface 4, which becomes smaller and smaller at the beginning and end and ends. In the case of the radially outer edge of the depressions 5 running continuously parallel to the cutting edge 1a, the distance between the radially inner edge of the depressions and the cutting edge 1a along their direction is preferably always smaller to zero at the beginning and end.

REFERENCE LIST

1

Cutting knife, sickle knife

1'

Rotation axis, knife axis, center

1"

Cutting plane

1a

Cutting edge, spiral

1.2

Knife back, back

2

rear cutting surface

1.1

Knife front, front side

3

front cutting surface

4th

Printing area

5

Depression, fillet

5 "

Cross sectional area

6th

Front recess

7th

Focus

8th

Grinding wheel

9

Circumferential direction, direction of the cutting edge

9.1

Cutting direction, circumferential direction

10

axial direction

11.1, 11.2

Transverse direction, radial direction

12

distance

20th

Cutting device, slicer

21st

Base frame

22nd

Product intake

23

Cutting glasses

24

Slider

25th

Retaining claw

b

Wide rear cutting surface

B.

Wide printing area

BV

Wide recess

d

Thick knives

D.

Thick slice

P

Product, strand, caliber

S.

disc

t

Depth of recess

δ

Cutting angle

α

Clearance angle

β

Pressure angle

Claims (15)

Knife (1) for machines, especially slicers, for cutting elastic products (P), especially elastic food products, into slices (S), whereby - A rear cutting surface (2), which forms part of the back of the knife (1.2) of the plate-shaped base body (3b) of the cutting knife (1), and a front cutting surface (3), which forms part of the knife front (1.1), is in meet a cutting edge (1a) at a cutting angle (δ), - the back of the knife (1.2) is curved outward from the cutting plane (1 ") defined by the cutting edge (1a) in the perpendicular to this, the axial direction (10), - the rear cutting surface (2) is followed by a pressure surface (4) on the back of the knife (1.2),
characterized in that - At least one recess (5) is formed in the back of the knife (1.2), - The size and / or the shape of the cross-sectional area (5 ") of the recess (5) lying transversely to the cutting plane (1") varies in the direction of the cutting edge (1a)
and or - The position, in particular the radial distance, of the recess (5) to the cutting edge (1a) varies in the direction of the cutting edge (1a). Knife according to claim 1,
characterized in that
the recess (5) is a fillet (5) which extends in particular primarily in the direction (9) of the cutting edge (1a). Knife according to one of the preceding claims,
characterized in that
the recess (5) is arranged in the pressure surface (4), and - extends from this in the direction facing away from the cutting edge (1a)
and or - extends in the direction of the cutting edge (1a) up to the beginning of the rear cutting surface (2). (Circular knife or sickle knife) Knife according to one of the preceding claims,
characterized in that - Either the cutting edge (1a) is endless, in particular circular - Or the cutting knife (1) is a sickle knife which has a finite cutting edge (1a) deviating from a circular shape, the distance of which from a center (1 ') also lying in the cutting plane (1 ") in a direction (9.1) of the Cutting edge (1a) steadily increases, in particular the cutting edge (1a) forms a spiral around the center (1 '). (Example 1, Figure 3a) Knife according to one of the preceding claims,
characterized in that - the recess (5), in particular the groove (5), extends only along part of the length of the cutting edge (1a), - With a finite cutting edge (1a) this ends at a distance from the beginning and / or before the end of the cutting edge (1a). Knife according to one of the preceding claims,
characterized in that
the size, shape and radial position of the cross-sectional area of the recess (5) along the direction (9) of the cutting edge (1a), in particular in the circumferential direction (9), is constant.
(Example 3, Figure 3b) Knife according to one of the preceding claims,
characterized in that - the cross-section of the recess (5), in particular the fillet (5), changes continuously in terms of size and / or shape and / or radial position along the direction (9) of the cutting edge (1a), in particular in the cutting direction (9.1), - In particular, its radial width in this direction (9), in particular the cutting direction (9.1), increases continuously. (Example 2, Figure 3c) Knife according to one of the preceding claims,
characterized in that - there are several depressions (5) one behind the other in the direction (9) of the cutting edge (1a), - which in particular are either designed identically or continuously different in size and / or shape and / or radial position in the course direction (9). Knife according to one of the preceding claims,
characterized in that - The thickness (d) of the base body (1b) of the knife (1) is a maximum of 15 mm, better a maximum of 12 mm, better a maximum of 8 mm
and or - the maximum depth (t) of the recess (5) is no more than 2 mm, better no more than 1 mm, better no more than 0.5 mm, better no more than 0.3 mm. Knife according to one of the preceding claims,
characterized in that - the depth (t) of the depression (5) a maximum of 20%, better a maximum of 10%, better a maximum of only 5% of the thickness (d) of the knife (1) at the end of the pressure surface (4) facing away from the cutting edge (1a) amounts to
and or - The recess (5) reaches up to the rear cutting surface (2) at least over part of its extension viewed in the plan view of the pressure surface (4). Knife according to one of the preceding claims,
characterized in that - the clearance angle (δ) between the cutting edge of the recess (5) and the pressure surface (4) changes along the direction (9) of the cutting edge (1a), - In particular in one direction (9), in particular continuously, increases or decreases. Knife according to one of the preceding claims,
characterized in that
the width (BV) of the depression (5) in the printing surface (4) measured perpendicular to the cutting edge (1a) is at least 30%, better at least 50%, better at least 70% of the width (B) of the printing surface (4). Cutting device (20), in particular slicer (20), for automatically cutting strand-like elastic products (P), in particular food products, into slices (S) - a base frame (21), - A product holder (22) attached to it, - a knife (1) which is rotatably attached about an axis of rotation (1 ') and which is arranged with its arched knife rear side (1.2) pointing away from the product receptacle (22),
characterized in that - The knife (1) is designed according to one of the preceding claims. Cutting device according to claim 13,
characterized in that - The finite cutting edge (1a) which deviates from a circular shape and runs around the axis of rotation (1 ') lies in the cutting plane (1 ") which runs perpendicular to the axis of rotation (1') and - the distance of the cutting edge (1a) from the axis of rotation (1 ') in a circumferential direction (9), the cutting direction (9.1), increases steadily, in particular increases continuously, - In particular the cutting edge (1a) forms a spiral around the axis of rotation (1 '). Method for using a cutting knife (1) according to one of the preceding claims 1 - 17 in a slicer (20),
characterized in that
the speed of the cutting blade (1) in use - is at least 500 rpm, better at least 700 rpm, better at least 1000 rpm, better at least 1200 rpm
and or - is not more than 3000 rpm, better is not more than 2500 rpm.

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