EP1075909A1 - Cutting knife - Google Patents

Abstract

Cutting knife has a fixing part with a receiver for fixing to an oscillating drive; a cutting part (22) with a cutter (28, 30); and a number of flat layers (34, 36, 38, 40) joined together, at least two of these layers being made of a metallic material. An Independent claim is also included for a process for the production of the cutting knife comprising producing a number of thin layers (34, 36, 38, 40); hot-joining the layers, preferably by forging to produce a metallic green body for the knife; heat treating by hardening or tempering; and post-processing the green body by grinding and/or polishing.

Description

The invention relates to a cutting knife for severing tough, elastic materials, especially for severing of adhesive beads on vehicle window panes, in wall joints etc., with a fastener that has a mounting bracket for attachment to an oscillation drive, and with a cutting part with at least one cutting edge.

The invention further relates to a method for producing a such cutting knife.

Such a cutting knife is known from EP-B-0 141 035.

Further cutting knives of a similar type are known from DE-A-3 626 762 and DE-B-3 838 044.

Such cutting knives are known, in particular, for cutting out of windshields used in motor vehicles, provided those due to damage or leaks need to be expanded. Another application is separation of leaky silicone joints made of masonry.

The known cutting knives have in common that when cutting of adhesive beads, for example when removing a damaged windshield a significant risk of breakage of a motor vehicle is available for the cutting knife.

The reason for this lies on the one hand in the tough material of the usually made of a certain type of polyurethane adhesive bead and on the other hand in spite of that with high frequency and small pivoting angle of the oscillating drive partially quite a lot of effort, especially when cutting wider adhesive beads, as is often the case with windshields occur that have already been replaced, so that the adhesive bead bead manually when installing the windshield had to be applied.

On the other hand, the cutting knives are due to the very resistant and tough material from which the adhesive bead is made, very quickly dull and have to be reground frequently become.

The known knives have so far all been made from a conventional one Knife steel made by first making a flat blank a suitable sheet was punched out, which then if necessary was bent provided the knife had a U-shaped cross-section or should have a bent shape, whereupon then an after-treatment by grinding if necessary connected. The knives were then hardened and then ground and optionally polished.

The knives known from EP-B-0 141 035 have a fastening opening in the form of a twelve-sided to form a positive Attachment to the drive shaft of the oscillation drive to enable. In contrast, the cutting knives are in accordance with the aforementioned DE-A-3 626 762 by a welded connection connected to the drive shaft. For knives according to the DE-B-3 838 044 attaches to the drive, as with a Jigsaw. These knives become oscillating in the longitudinal direction driven.

However, such knives are also made from a knife steel, hardened and sanded before use.

In addition, cutting knives are on the market through use become known whose surface is covered with a thin layer Titanium nitride was provided, apparently by CVD (chemical vapor deposition) was applied.

However, such knives could not in practice enforce because the applied titanium nitride layer is so thin was that it was useless in practice, since it was only once Resharpening had practically no effect. Moreover the production by CVD is relatively complex and expensive. Further These knives coated with titanium nitride were also subject the previously described problems of susceptibility to breakage.

The object of the invention is therefore an improved Cutting knife and a method for producing such specify that enables improved cutting performance and has the lowest possible susceptibility to breakage, so that overall a longer service life is possible.

This task is performed with a cutting knife of the type mentioned Art solved in that the cutting knife from a plurality consists of planar interconnected layers, wherein at least two of these layers made of a metallic Material.

The object of the invention is completely achieved in this way, because of a multi-layer structure of the cutting knife from a plurality of individual, flatly interconnected Metal layers have better properties overall Knife achieve, namely a particularly high one Hardness and wear resistance on the cutting edge and on the other hand, significantly improved elasticity and achieve reduced susceptibility to breakage.

Although it has been used in the manufacture of so-called for centuries Damascus blades, i.e. in the manufacture of sabers and Daggers are known to make them from individual layers, which are forged together is a transmission of this Manufacturing process for the manufacture of cutting knives, used in conjunction with an oscillation drive not to cut tough, elastic materials obvious.

The cutting knives according to the invention are namely for mass parts made by joint renovators, car workshops and are required by glaziers in large numbers, since the relevant cutting knife after a relatively short time are dull or break off. This can often be done with a single Cutting knife only cut out a single windshield become.

In contrast, Damascus blades are only made by hand, the manufacture being extremely complex and is expensive, so for modern knives that come from a variety consist of individual layers that are forged together, three or even four-digit EURO amounts have to be paid. The well-known knives have been used since 1983, so far however not yet considered a knife with several Use metal layers.

It is therefore not obvious, such an expensive and complex Manufacturing process on the manufacture of cutting knives of the type in question.

In an advantageous development of the invention, the metallic ones Layers joined together by hot bonding, preferably forged together.

Although basically metallic forged together Layers are characterized by particularly good properties it is also possible to interact with each other in other ways to use connected metallic layers. For example a flat welding of the metallic Layers conceivable with each other, for example through a special Resistance welding process with simultaneous application of Pressure can be achieved. Friction welding is also possible. Recently, it is also possible to use different metal layers for this purpose to connect with each other by gluing.

According to a further embodiment of the invention, some of the Layers of materials with different material properties manufactured.

In this way, the properties of the cutting knife in to be "tailor-made" in a way. For example middle layers can be provided, the lower Hard, but higher toughness and flexural strength exhibit. Outwardly, the layers can gradually become one greater hardness and lower toughness or flexural strength own, and vice versa. It is basically possible to use the different To produce layers from the same material that but is only pretreated differently, for example one has different degrees of deformation (e.g. use of cold-rolled or annealed steel) or these properties only when heat treatment of the interconnected To create layers. However, it is particularly preferred special materials, which also match the composition of the desired properties are adapted to use, for example a special one in a defined area of the cutting part To achieve high elasticity and flexural strength and in particular on the cutting edge a particularly high hardness and possibly reduced friction in the outermost layers. At In some applications, it can also make sense to use the outer one Layers of a soft and / or particularly elastic To produce material. This is advantageous, for example, if adhesive beads are to be removed or severed, which are attached to painted surfaces on plastic or wood are.

Even the outermost metal layers can be a special Undergo surface treatment, such as boronization, carburization, nitrocarburization or the like, a particularly high hardness in the outermost layers in the area of at least one cutting edge.

According to a further embodiment of the invention, there is at least one of the layers of a wear-resistant material, preferably made of tungsten carbide, silicon carbide, titanium carbide, Chromium oxide, silicon oxide, titanium oxide, aluminum oxide, boron nitride, Titanium nitride, molybdenum or mixtures thereof or mixtures or alloys with other metals.

With this additional layer of a wear-resistant So material is a layer that is not made of the same material as the other metallic layers, about a certain steel, but instead that of an inorganic, generally non-metallic Material such as a carbide, an oxide, a nitride. In addition, to achieve high hardness and wear resistance a coating of molybdenum is also conceivable.

However, these additional coatings are not like the others metallic layers by hot joining or forging can be applied but by a special coating process, such as vapor deposition or another Processes such as thermal spraying.

In an additional development of the invention contains at least an outer layer of the cutting part, friction-reducing additives, preferably inclusions of molybdenum sulfide and / or Graphite.

This makes working when cutting through adhesive beads considerably easier because of the friction reducing additives, which in the form of microscopic inclusions in at least the outer coating can be provided, the friction is significantly reduced, thereby reducing the service life is improved.

In a further modification of the invention there is at least one external one Layer of the cutting part made of PTFE (Teflon).

The non-stick effect of PTFE makes the frictional resistance significantly reduced when cutting through an adhesive bead. One Adhesive effect of sealants when severed is counteracted. Due to reduced friction, the temperature at Cutting process lowered. This causes the tendency to occur significantly reduced by vapors. It can advantageously Colored Teflon used to be different To mark designs or make an aesthetic impression improve.

In a further advantageous embodiment of the invention, this Cutting part on a sickle-shaped curved blade, which preferably is concavely curved with respect to the clamping point, wherein the cutting knife further has a U-shaped angled cross section can have, wherein the cutting part with the fastening part is connected via an intermediate part, as is in itself is known in the art.

It has been shown that with such geometries of the cutting knife a particularly favorable cutting effect is achieved and a windshield with a U-shaped angled cross section can be separated from the outside. Furthermore however, other shapes are also conceivable, such as angled or cranked blades or cutting knife with a roller as a stop, like this basically e.g. from EP-B-0 174 427 already is known.

According to a further embodiment of the invention, this Cutting knife a mounting bracket for connection to a Rotary oscillation drive on. In an alternative version of the Invention, the cutting knife has a mounting receptacle Connection with an oscillating drive oscillating in the longitudinal direction on.

With both embodiments, the invention can Use cutting knife advantageously.

In an additional development of the invention, the cutting knife a core area that consists of an elastic and / or soft material.

In an additional development of this embodiment, this Cutting knife on a cutting part, which is preferably only in Area of at least one cutting edge with the different Layers is provided.

Through these measures, the manufacture of the cutting knife simplified because the core area is made of elastic and / or soft material in a relatively simple way, for example can be made from a sheet by punching, at the same time a mounting receptacle in the form of an opening can be punched out, whereupon then in the area of Cutting part to be applied to the different layers to achieve the properties necessary for the cutting part. As far as the cutting knife also has an intermediate part, can the additional layers of course also over this Part extend, for example, a particularly high toughness and bending strength in the area of the intermediate part achieve.

Overall, the production is simplified and designed significantly cheaper.

(a) Herstellen einer Mehrzahl von dünnen metallischen Schichten,

(b) Heißverbinden der metallischen Schichten, vorzugsweise durch Schmieden, zur Erzeugung eines metallischen Rohlings für das Schneidmesser,

(c) Wärmebehandeln des Rohlings zur Verbesserung der Härte und/oder Biegebruchfestigkeit vorzugsweise durch Härten oder Vergüten des Rohlings,

(d) Nachbearbeiten des Rohlings durch Schleifen und/oder Polieren.

With regard to the method, the object of the invention is achieved by a method for producing a cutting knife for severing tough, elastic materials, in particular for severing adhesive beads, for example on vehicle window panes, with a fastening part which has a fastening opening for fastening to an oscillation drive, and with a cutting part with at least one cutting edge, solved with the following steps:

(a) producing a plurality of thin metallic layers,

(b) hot bonding the metallic layers, preferably by forging, to produce a metallic blank for the cutting knife,

(c) heat treating the blank to improve the hardness and / or flexural strength, preferably by hardening or tempering the blank,

(d) reworking the blank by grinding and / or polishing.

In this way, a cutting knife according to the invention can be with significantly improved properties, the one high stability, especially high toughness and flexural strength with good hardness and wear resistance the cutting edge or cutting unites.

It is understood that the individual metallic layers are made of different alloyed metals can exist.

For hot joining the metallic layers, it is preferred uses a forging process, i.e. a connection at accordingly high temperature under pressure from hammering or similar. In addition, it is conceivable to have an intimate Connection also by pressing at a sufficiently high temperature to generate, provided the pressing tools are sufficiently mechanical and are thermally stable. It is also conceivable to have an intimate Connection by friction welding or by a special resistance welding process with additional application of flat To generate pressure.

In a preferred development of the method according to the invention the fastening opening after the heat treatment according to Step (c) generated, preferably by electrical discharge machining or Laser cutting.

Since it is in the manufacture of the blank by hot joining several metallic layers is difficult, the necessary dimensional accuracy to achieve for the mounting bracket at which it e.g. around an opening in the form of a regular polygon, the manufacturing process becomes like a dodecagon in this way simplified by first creating a flat metallic Blank with a suitable process in a simple manner is generated, which are heat treated in a suitable manner can to achieve the desired mechanical properties, wear resistance and hardness to achieve. To make the A spark erosion process is available for mounting or a laser cutting process with which the attachment holder as an opening in a relatively inexpensive way with sufficient Dimensional accuracy can be generated.

If the cutting knife should not be flat, but to be provided with a certain bend, so the blank is hot bent before undergoing the heat treatment to improve hardness and / or flexural strength, that means hardening and tempering. In the The use of steel therefore preferably takes place in red-hot condition.

In a modification of the method described above, this can Cutting knife from a blank from an elastic and / or be made of soft material, at least in the area its at least one cutting edge has a plurality of metallic ones Layers is applied.

Such a production is - as already explained above - The manufacturing process is simplified and considerably cheaper designed. This is because in further training this version of the blank from the elastic and / or soft Material together with the mounting bracket Punches are manufactured. Only in the area of the cutting knife, in which specially improved properties are necessary in particular in the area of the cutting part and if necessary in the area of the intermediate part, the different metallic layers used.

If the metallic layers just over the cutting part extend, a bend to produce a U-shaped angled or cranked knife even when cold be performed.

In an additional development of the method according to the invention is at least one additional wear-resistant layer on the Cutting part applied.

In a preferred development, this can be a Layer of tungsten carbide, silicon carbide, titanium carbide, chromium oxide, Silicon oxide, titanium oxide, aluminum oxide, boron nitride, Titanium nitride, molybdenum or mixtures or alloys with others Trade metals.

As previously mentioned, this can be done Cutting knife with a particularly hard and wear-resistant blade produce, however, sufficient elasticity and flexural strength having.

The wear-resistant layer or the wear-resistant layers are in a preferred development of the invention either by deposition from the gas phase (CVD or PVD) or by thermal spraying, preferably generated by plasma spraying.

While only very thin layers are found in CVD or PVD can be produced in a complex and expensive manner the application of a thermal spray process a very achieve a dense coating with a greater thickness, the one Thickness on the order of up to about a millimeter can have.

Only a sufficiently thick coating, at least in the area the at least one cutting edge leads to a cutting knife significantly improved cutting properties because of a coating of only a small thickness on the order of a few Micrometers already at the first sharpening or when sharpening loses its effect because it is completely in the area of the cutting edge is removed.

According to a further embodiment of the method according to the invention becomes the wear-resistant layer by thermal spraying made of carbides in a metallic coating, preferably in nickel, cobalt or alloys thereof are included.

In this way, carbides can also be sprayed thermally, the nickel, preferably used for the coating, Cobalt and other alloys usually add carbides have between 8 and 30 percent by weight. When melting the coating in the flame reacts with the carbides the most varied of phases. Here are in particular Tungsten carbide layers, chromium carbide layers or carbide metals conceivable. Are oxidic layers by thermal Syringes produced, their properties can be mixed and alloys can be improved. For example an alumina layer can be used with 3 percent up to 40 weight percent titanium oxide is interspersed with achieve a relatively high hardness with reduced brittleness leaves.

In an additional development of the method according to the invention are the wear-resistant layer friction-reducing additives added. This can be microscopic, for example small inclusions of molybdenum sulfide and / or graphite act.

Because of the risk of oxidation, spraying is necessary required under protective gas.

(a) Herstellen eines Rohlings aus einem Stahl,

(b) Wärmebehandeln des Rohlings zur Erzeugung einer hohen Elastizität und Biegebruchfestigkeit, vorzugsweise durch Vergüten des Rohlings,

(c) Nachbearbeiten des Rohlings vorzugsweise durch Schleifen und/oder Polieren,

(d) Auftragen mindestens einer verschleißfesten Schicht auf das Schneidteil durch thermisches Spritzen.

In an alternative embodiment of the invention, the method for producing a cutting knife has the following steps:

(a) making a blank from a steel,

(b) heat-treating the blank to produce high elasticity and flexural strength, preferably by tempering the blank,

(c) reworking the blank, preferably by grinding and / or polishing,

(d) applying at least one wear-resistant layer to the cutting part by thermal spraying.

A cutting knife with high elasticity can also be made in this way and bending strength with good at the same time Establish cutting properties.

The manufacture is compared to the manufacture from one Majority of metallic individual layers considerably cheaper, there is an elaborate hot connection, for example by forging many Individual layers are omitted.

Rather, the cutting knife can be used in the usual way be made from a suitable knife steel, the however, a special heat treatment to achieve a high Is subjected to elasticity and flexural strength, so not the usual hardness treatment as with conventional ones Cutting knives. Accordingly, a hardening process may involve a tempering process to temper to connect to at reduced hardness an increased elongation at break and elasticity, as well as an improved To achieve bending strength.

The normally inadequate with such a knife Hardness in the area of the at least one cutting edge is now invented by applying a wear-resistant Layer achieved by thermal spraying. By applying the thermal spraying can be a layer with sufficient Thickness can be achieved despite being insufficient hard blanks extraordinarily, at least in the area of the cutting edge good cutting properties, in particular high cutting properties Achieve hardness and wear resistance.

The wear-resistant layer can be made of molybdenum, for example Carbide, an oxide, a carbide metal, an oxide metal or mixtures thereof.

As already mentioned above, it is again particularly preferred the wear-resistant layer by thermal spraying of carbides, which are in a metallic coating, preferably nickel, cobalt or alloys thereof are.

In a preferred further treatment of the invention, the blank pretreated by roughening before thermal spraying.

In this way, an improved adhesion of the thermally sprayed Layer reached on the surface of the blank.

In additional training this version is before Spray on the wear-resistant layer an adhesion promoter layer sprayed on.

This enables a further improved adhesion of the wear-resistant Layer on the cutting knife, disadvantages that due to differences in the coefficients of thermal expansion are partially compensated.

The blank is in a preferred development of the invention Procedure together with the mounting fixture Stamping made.

In this way, the manufacturing process is significantly simplified and designed significantly cheaper, as with the hitherto usual production of conventional cutting knives Was the case, but which had no improved properties.

Here, in the case of an angled cross section Bend generated before the heat treatment according to step (b).

Again, the wear-resistant layer can reduce friction Additives, preferably inclusions made of molybdenum sulfide and / or graphite can be added.

It is understood that the above and those below Features of the invention still to be discussed no longer in the specified combination, but also in others Combinations or alone can be used without the Leave the scope of the invention.

Fig. 1

eine Ansicht eines erfindungsgemäßen Schneidmessers von vorn, wobei zusätzlich ein Oszillationsantrieb angedeutet ist, an dem das Schneidmesser befestigt ist;

Fig. 2

eine Seitenansicht des Schneidmessers gemäß Fig. 1;

Fig. 3

eine sogenannte Abwicklung des Schneidmessers gemäß Fig. 2, d.h. einen ebenen Rohling, aus dem das Schneidmesser gemäß den Fig. 1 und 2 durch Biegen herstellbar ist;

Fig. 4

einen Schnitt durch den Schneidteil gemäß Fig. 2 längs der Linie IV-IV in vergrößerter, schematisierter Darstellung;

Fig. 5

einen Schnitt durch den Schneidteil gemäß Fig. 2 längs der Linie IV/IV in vergrößerter, schematischer Darstellung, jedoch in leicht abgewandelter Ausführung;

Fig. 6

eine Ansicht einer weiteren Abwandlung eines erfindungsgemäßen Schneidmessers;

Fig. 7

einen Schnitt durch das Schneidmesser gemäß Fig. 6 längs der Linie VII-VII in vergrößerter Darstellung;

Fig. 8

eine Seitenansicht des Schneidmessers gemäß Fig. 6;

Fig. 9

eine Abwandlung des Schneidmessers gemäß Fig. 8 in abgekröpfter Ausführung;

Fig. 10

eine weitere Abwandlung des Schneidmessers gemäß Fig. 8 in gebogener Ausführung; und

Fig. 11

eine Ansicht einer weiteren Abwandlung eines erfindungsgemäßen Schneidmessers, das zur Verbindung mit einem Längsoszillationsantrieb geeignet ist.

Further features and advantages of the invention result from the following description of preferred exemplary embodiments with reference to the drawing. Show it:

Fig. 1

a view of a cutting knife according to the invention from the front, wherein an oscillation drive is additionally indicated, to which the cutting knife is attached;

Fig. 2

a side view of the cutting knife of FIG. 1;

Fig. 3

a so-called development of the cutting knife according to FIG. 2, ie a flat blank, from which the cutting knife according to FIGS. 1 and 2 can be produced by bending;

Fig. 4

a section through the cutting part of Figure 2 along the line IV-IV in an enlarged, schematic representation.

Fig. 5

a section through the cutting part of Figure 2 along the line IV / IV in an enlarged, schematic representation, but in a slightly modified version.

Fig. 6

a view of a further modification of a cutting knife according to the invention;

Fig. 7

a section through the cutting knife of FIG 6 along the line VII-VII in an enlarged view.

Fig. 8

a side view of the cutting knife of FIG. 6;

Fig. 9

a modification of the cutting knife according to Figure 8 in a cranked version.

Fig. 10

a further modification of the cutting knife according to Figure 8 in a curved design. and

Fig. 11

a view of a further modification of a cutting knife according to the invention, which is suitable for connection to a longitudinal oscillation drive.

1 shows a cutting knife according to the invention as a whole number 10. The cutting knife 10 is put together used with an oscillation drive 12 with rotary oscillation, which is only indicated schematically in Fig. 1, and its Drive shaft 14 with a high frequency in the range between about 5,000 and 28,000 vibrations per minute with a small swivel angle in the range between about 0.5 and 7 degrees around Longitudinal axis 18 of the drive shaft can be driven to oscillate.

1 has a U-shaped angle Cross section and has a fastening part 20 and one sickle-shaped curved cutting part 22, which with the fastening part 20 is connected via an intermediate web 24.

2 is a mounting receptacle 26 provided in the form of an opening, which as a regular Polygon, in the case shown as a star-shaped twelve-sided and that is a positive fixation on the drive shaft 14 allowed. For securing on the drive shaft 14 also serves a screw 16, which is in a not shown Threaded blind hole of the drive shaft 14 is screwed.

In Fig. 3, a flat blank 32 is shown, from which the Cutting knife 10 according to FIGS. 1 and 2 by bending and others subsequent processing steps can be produced.

Although the cutting knife 10 shown here is U-shaped has angled cross-section, are also any other Knife shapes conceivable. For example, a flat cutting knife could also be used approximately in the shape of the blank 32, the final shape of the Represent cutting knife. In addition, the cutting knife could e.g. also have a bent shape or a flat shape and if necessary with a stop roller to limit the Depth of cut, as per itself e.g. from the DE-A-3 304 981 and from EP-B-0 174 427.

Various such variants are shown in FIGS. 6, 8, 9 and 10 exemplified.

The cutting knife 10b shown in FIGS. 6 and 8 is just formed and has a fastening part 20b with a round mounting receptacle 26b and a cutting part 22b two straight cutting edges 28b and 30b, starting from the fastening part 20b to a common tip that is rounded is, converge towards it, so that there is an approx wedge-shaped cutting part 22b results. A cranked cutting knife 10c is shown in Fig. 9, while in Fig. 10b one curved cutting knife 10d is shown.

The cutting knife 10 according to the invention is now characterized a special type of manufacture, which is explained below becomes.

According to a first variant of the invention, the cutting knife 10 made from a variety of thin metal layers, which are connected by a forging process. The individual layers can be made from thinly rolled sheets are punched out before they are forged together get connected. The sheets are preferably made of steel, in particular from a knife steel of a suitable composition, different steels for the different layers can be used with different compositions, to "tailor-made" properties for the cutting knife 10 produce.

As can be seen from Fig. 4, the cutting knife 10 can e.g. on Have cutting part 22 which is ground crowned on both sides and is provided with a blade 28 and 30 on each side. It can consist of a central layer 34, a subsequent one Layer 36 and an outer metallic layer 38, and on the outside it is also completely thermal sprayed wear-resistant layer 40 may be surrounded.

It goes without saying that the representation according to FIG. 4 is purely schematic Is natural and only the structure of the cutting part 22nd 34 to 40 from individual layers. The number of the layers can be a multiple of the number shown.

The individual metallic layers 34, 36, 38 of the blank after its production by punching connected by forging. The attachment opening 26 preferably only after the forging process, however before the application of the thermally sprayed layer 40 generated.

Because punching like in the production of conventional Cutting knives is not easily possible, the mounting bracket 26 preferably by a spark erosion method or generated by laser cutting, which is a relatively inexpensive Manufacturing and still high dimensional accuracy allowed.

After the individual layers 34, 36, 38 have been forged the blank 32 thus produced is bent in the red-hot state, to create the U-shaped angled shape of the cutting knife.

Subsequently, the Cutting knife 10 to have high elasticity and bending strength the core layer 34 to generate the outward decreases through layer 36 into layer 38, but at the same time the wear resistance and hardness increases.

These bespoke properties can still be improved that the material selection of the middle layers 34 or 36 and the outer layer 38 specifically targeted in this way will that depending on the heat treatment in the core area a higher Achieve elasticity, toughness and flexural strength leaves and in the outer area a higher hardness and wear resistance, what there with a lower flexural strength is bought. In some cases it can also make sense to provide a soft layer on the outside, e.g. if the adhesive bead is attached to painted surfaces on plastic or wood.

After the bending and heat treatment of the cutting knife 10 is this only in the area of the cutting part 22 from both sides by spraying the layer 40 by thermal spraying, preferably coated by plasma spraying.

This layer 40 is preferably an oxide layer or carbide layer, optionally with metal additives or a layer of molybdenum, which is also high Has hardness and wear resistance.

A particular advantage when using the thermal Spraying to achieve the outer layer 40 is that this layer 40 with a sufficient thickness of the order of magnitude from a few tenths to about a millimeter or even more can be applied in a relatively inexpensive way can, whereby this thermally sprayed layer 40 a sufficient Has strength to even with multiple resharpening during the use of the cutting knife 10 the cheap To maintain cutting properties. The thermally sprayed Layer 40 may be made of tungsten carbide, for example be in a nickel, cobalt or whose alloys are embedded, the amount of metal between can be about 8 and 30 weight percent. It can for example, the carbide metal 85 WC 15 Co-Cr, the high hardness with relatively high breaking strength distinguished. The coating can also be selected that the coefficient of thermal expansion is as close as possible to the coefficient of expansion of the metallic blank. This will result in better adhesion even under thermal stress reached and chipping avoided.

An alternative cross-sectional shape of the cutting part is in Fig. 5 shown and designated overall by the number 22a. Again, the cutting part 22a consists of several layers one Knife steel, but essentially has a cross section rectangular shape and is only on the side its cutting edge 28a facing the fastening opening 26 is bevelled on one side, while on the mounting hole 26 facing away from both sides Cutting edge 30a is provided, but not so is sharpened, as is the case with the cutting edge according to FIG. 4 the case is.

This cutting edge 30a only serves as an "emergency cutting edge" Return the cutting knife in an already cut one Part of the adhesive bead should allow.

As a result, it occurs with the individual metallic layers 34a, 36a, 38a and 42, 44 do not suggest that these are also in the area the cutting edge 30a to a high hardness and wear resistance are designed.

4, the outer layers 36 and 38 forged on both sides around the core layer 34 are, so that a spherical cross-sectional shape already during the forging process arises, the layers 34a, 36a, 38a or 42, 44 in a largely flat manner according to FIG. 5 by forging connected. Because the middle layer 34a is specifically for a high Elasticity and flexural strength is designed and the layers 36a and 42 adjoining on both sides a little have less elasticity, but greater Hardness and wear resistance, especially the layer 38a on one side, towards which the cutting edge 28a is wedge-shaped is bevelled on one side, for a particularly high Hardness and wear resistance designed.

In addition, as shown in FIG. 5, a thermally sprayed one Layer 40a be applied. That of the thermally sprayed Layer 40a opposite outer layer 44 the other side of the cutting part 22a is not special for one high hardness, but more for good elasticity and Flexural strength, because there are none on this side Cutting edge is provided.

As already mentioned, the second cutting edge 30a occurs the side facing away from the mounting opening 26 Cutting part 22a does not have particularly good cutting properties as this only serves as an auxiliary cutting edge.

In a variant of the embodiment described above, too the blank 32 from a knife steel of suitable thickness in one single operation can be made by punching, whereby at the same time the fastening opening 26 is punched out. In this case, the properties of the knife steel are special designed for high elasticity and flexural strength, which also in the subsequent heat treatment - if necessary after a previous bending process - taken into account becomes. Therefore, the knife steel is not, as usual, only hardened, but preferably hardened first and then over a sufficiently long period of time with a sufficiently high one Tempered to get such compensation, that there is good flexural strength. The necessary The sharpness of the cutting edge 28a becomes essentially in this case through one or more layers of the thermally sprayed Layer 40a achieved sufficient for this purpose Thickness must be applied. Such a layer therefore points preferably a thickness of 0.5 to 1 millimeter. To one improved adhesion of this wear-resistant layer 40a on the to achieve metallic base body, this is before the thermal Syringes are first machined, e.g. boned, ground and polished if necessary, whereupon then a roughening (fine sandblasting with corundum or the like). Thereupon there is first an adhesion promoter layer applied, on which then the wear-resistant Layer 40a is sprayed on, if necessary can be done in multiple layers to produce the desired thickness.

The wear-resistant layer 40a can in turn, how previously mentioned, such as an oxide or carbide layer act or a molybdenum layer.

If necessary, the wear-resistant layer 40 or 40a still friction-reducing additives as microscopic Inclusions are integrated, for example from molybdenum sulfide or graphite, where the thermal Spraying process to prevent oxidation under protective gas he follows.

5 is preferably as shown only sharpened from one side to avoid that the wear-resistant layer 22a in the area of the cutting edge 28a their effect loses what with a bilateral sharpening would be the case.

The cutting knife 10b shown in FIGS. 6 and 8 differs different from the previously described versions in another aspect.

The cutting knife 10b is namely from a blank from one elastic and / or soft material made on the only a plurality of metallic ones in the area of the cutting part Layers is applied to the desired cutting area improved properties, namely on the one hand high Toughness and flexural strength and, on the other hand, high Hardness on the outer layers in the area of the cutting edges 28b and To achieve 30b.

This structure is apparent from Fig. 7, which is a section along the line VII-VII of FIG. 6 in an enlarged view shows.

The cutting knife 10b has a core area 42 which consists of a relatively soft, but elastic and tough steel is, with the core area essentially over the Fastening part 20b extends while in the area of the cutting part 22b different metallic layers 34b on both sides, 36b and 38b one after the other to one starting from the core region 42 thin web 44 are applied. During the web 44 out the material of the core area 42, they can be made thereon applied layers 34b, 36b and 38b made of other materials, preferably steels consist of a high overall Achieve strength and elasticity, as well as high hardness in the area of the outermost layer 38b on the cutting edges 28b and 30b.

A knife constructed in this way is considerably easier and less expensive produce because the elaborate production about by forging the metallic layers 34b, 36b and 38b only is limited to the cutting part 22b during the manufacturing used blank cheaper e.g. by punching including the mounting receptacle designed as a circular opening 26b can be manufactured.

Another modification of a cutting knife according to the invention is shown in Fig. 11 and generally designated by the number 10c.

The cutting knife 10c according to FIG. 11 is opposite to that previously described versions not for connection to a Rotary oscillation drive suitable, but for connection with a longitudinal oscillation drive, as indicated by arrow 48 is. At the machine end of the cutting knife 10c a receptacle 26c is provided which has recesses 46 on both sides with which the cutting knife like in a jigsaw the longitudinal oscillation drive is clamped. At the bottom of the cutting knife 10c, the cutting part 22c is formed, which again has a core area 42c, on both sides, as previously explained with reference to FIG. 7, metallic Layers are applied to create cutting edges 28c and 30c.

Such a cutting knife can, for example, as in DE-A-3 838 044 can be used.

Further designs of a cutting knife according to the invention are shown in FIGS. 9 and 10 and overall with the Numbers 10d and 10e designated. 9 shows a cutting knife FIG. 10d shows an offset in FIG. 10 is a Cutting knife 10e shown in a curved version.

Claims (32)

Cutting knife for cutting tough, elastic materials, especially for cutting adhesive beads for example on vehicle window panes or on wall joints, with a fastening part (20) which has a fastening receptacle (26; 26b) for attachment to an oscillation drive (12), and with a cutting part (22; 22a; 22b; 22e) with at least one cutting edge (28, 30; 28a, 30a; 28b, 30b; 28c, 30c), characterized in that the Cutting knife (10) a plurality of flat with each other connected layers (34, 36, 38, 40; 34a, 36a, 38a, 40a, 42, 44; 34b, 36b, 38b), at least two of these layers (34, 36, 38; 34a, 36a, 38a, 42, 44; 34b, 36b, 38b) consist of a metallic material. Cutting knife according to claim 1, characterized in that the metallic layers (34, 36, 38; 34a, 36a, 38a, 42, 44; 34b, 36b, 38b) connected to one another by hot bonding are, are preferably forged together. Cutting knife according to claim 1 or 2, characterized in that that individual of the layers (34, 36, 38; 34a, 36a, 38a, 42, 44; 34b, 36b, 38b) made of materials with different Material properties are made. Cutting knife according to claim 3, characterized in that at least one outer layer (38, 40; 38a, 40a; 38b) is provided is, the good cutting properties, in particular has a high hardness, and that at least one inner Layer (34, 36; 34a, 36a; 34b, 36b) is provided, the has good elasticity and high flexural strength. Cutting knife according to claim 3, characterized in that at least one outer layer (38, 40; 38a, 40a; 38b, 40b) is provided, which is made of a softer material than that remaining layers and / or greater elasticity than the other layers. Cutting knife according to one of the preceding claims, characterized characterized in that at least one (40; 40a) of the Layers (34, 36, 38, 40; 34a, 36a, 38a, 40a, 42, 44; 34b, 36b, 38b) made of a wear-resistant material, preferably made of tungsten carbide, silicon carbide, titanium carbide, Chromium oxide, silicon oxide, titanium oxide, aluminum oxide, boron nitride, Titanium nitride, molybdenum or mixtures thereof. Cutting knife according to one of the preceding claims, characterized characterized in that at least one outer layer (40; 40a) of the cutting part (22; 22a) reducing friction Additives, preferably inclusions made of molybdenum sulfide and / or contains graphite. Cutting knife according to one of claims 1 to 6, characterized characterized in that at least one outer layer (40; 40a) of the cutting part (22; 22a) consists of PTFE. Cutting knife according to one of the preceding claims, characterized characterized in that the cutting part (22; 22a) is sickle-shaped is curved. Cutting knife according to one of the preceding claims, characterized characterized in that the cutting knife (10; 10a) a Has a U-shaped angled cross-section, the Cutting part (22; 22a) with the fastening part (20) an intermediate part (24) is connected. Cutting knife according to one of the preceding claims, characterized characterized in that the cutting knife (10; 10a; 10b) a mounting receptacle (26; 26b) for connection to a Has rotary oscillation drive (14). Cutting knife according to one of the preceding claims, characterized characterized in that the cutting knife (10c) has a mounting receptacle (26c) for connection to an in Longitudinally oscillating oscillation drive. Cutting knife according to one of the preceding claims, characterized characterized in that the cutting knife (10b; 10c) a Has core region (42; 42c), which consists of an elastic and / or soft material. Cutting knife according to claim 13, characterized in that the cutting knife (10b; 10c) has a cutting part (22b; 22c), which in the region of the at least one cutting edge (28b, 30b; 28c, 30c) with different layers is. Method for producing a cutting knife (10) for severing tough, elastic materials, in particular for severing adhesive beads on vehicle window panes, with a fastening part (20; 20b; 20c) which has a fastening receptacle (26, 26b; 26c) for fastening has an oscillation drive (12), and with a cutting part (22; 22a; 22b; 22c) with at least one cutting edge (28, 30; 28a, 30a; 28b, 30b; 28c, 30c), with the following steps: (a) producing a plurality of thin metallic layers (34, 36, 38; 34a, 36a, 38a, 42, 44; 34b, 36b, 38b), (b) hot bonding the metallic layers (34, 36, 38; 34a, 36a, 38a, 42, 44; 34b, 36b, 38b), preferably by forging, to produce a metallic blank (32) for the cutting knife (10), (c) heat treating the blank (32), preferably by hardening or tempering the blank (32), (d) reworking the blank (32) by grinding and / or polishing. The method of claim 15, wherein the mounting receptacle (26) after the heat treatment in step (c) is, preferably by electrical discharge machining or laser cutting. The method of claim 15, wherein the cutting knife (10b; 10c) from a blank from an elastic and / or soft material is made on the at least in the area of its at least one cutting edge (28b, 30b; 28c, 30c) applied a plurality of metallic layers becomes. The method of claim 17, wherein the blank from the elastic and / or soft material together with the mounting bracket (26b) is produced by stamping. The method of claim 15 or 16, wherein the blank (32) to produce a preferably U-shaped angled or bent cross section when hot becomes. Method according to one of claims 15 to 19, in which at least an additional wear-resistant layer (40; 40a) is applied to the cutting part. The method of claim 20, wherein the wear resistant Layer (40; 40a) made of tungsten carbide, silicon carbide, titanium carbide, Chromium oxide, silicon oxide, titanium oxide, aluminum oxide, Boron nitride, titanium nitride, molybdenum, or mixtures is made from it. 22. The method of claim 20 or 21, wherein the at least a wear-resistant layer (40; 40a) by thermal Spraying, preferably by plasma spraying or by CVD or PVD is applied. The method of claim 20 or 21, wherein the wear-resistant Layer (40; 40a) by thermal spraying of carbides is produced in a metallic Coating, preferably in nickel, cobalt or alloys of which are included. Method according to one of claims 20 to 23, wherein the wear-resistant layer (40; 40a) friction-reducing Additives, preferably inclusions made of molybdenum sulfide and / or graphite can be added. Method for producing a cutting knife (10) for severing tough, elastic materials, in particular for severing adhesive beads on vehicle window panes, with a fastening part (20; 20a) which has a fastening receptacle (26; 26b) for fastening to an oscillation drive (12 ), and with a cutting part (22; 22a) with at least one cutting edge (28, 30; 28a, 30a), with the following steps: (a) producing a blank (32) from a steel, (b) heat treating the blank (32), preferably by tempering the blank (32), (c) reworking the blank (32), preferably by grinding and / or polishing, (d) applying at least one wear-resistant layer (40; 40a) to the cutting part (22; 22a) by thermal spraying. The method of claim 25, wherein the wear-resistant Layer (40; 40a) made of molybdenum, a carbide, an oxide, a carbide metal, an oxide metal or mixtures of which is manufactured. The method of claim 26, wherein the wear-resistant Layer (40; 40a) by thermal spraying of carbides which is made in a metallic envelope, preferably in nickel, cobalt or alloys thereof are included. The method of claim 25, 26 or 27, wherein the blank (32) before thermal spraying by roughening is pretreated. Method according to one of claims 25 to 28, in which the spraying of the wear-resistant layer (40; 40a) Bonding agent layer is sprayed on. Method according to one of claims 25 to 29, wherein the Blank (32) with the mounting receptacle (26) by punching will be produced. A method according to any one of claims 25 to 30, wherein the Blank (26) for producing a preferably U-shaped angle or cranked cross-section before the heat treatment is bent according to step (b). Method according to one of claims 25 to 31, wherein the wear-resistant layer (40; 40a) friction-reducing Additives, preferably inclusions made of molybdenum sulfide and / or graphite can be added.

Images