EP3530425A1 - Ultrasonic vibration cutting device and cutting tool for an ultrasonic vibration cutting device - Google Patents

Abstract

The invention relates to a cutting tool (1) for an ultrasonic cutting device (10) and ultrasonic cutting device (10) with sonotrode (11) and cutting tool (1). The cutting tool (1) comprises a cutting end (2) and a fastening end (3) for insertion into a tool holder or a sonotrode (11). From the attachment end (3) of the cutting tool (1) extends at least one positive locking block (4) away. At least one complementary form-fitting recess (17) is provided on the sonotrode (10), so that the form-fitting block (4) with the form-fitting recess (17) forms a positive fit at least in a longitudinal direction (25) which surrounds the cutting end (2) and the attachment end (3 ), when the cutting tool (1) is mounted in the sonotrode (11).

Description

The invention relates to a cutting tool for an ultrasonic cutting device and ultrasonic cutting device according to the preambles of the independent claims.

Ultrasonic cutting devices for cutting textiles, films, rubber compounds, foods, etc. have long been known. For the cutting / separating effect, the high-frequency ultrasonic vibrations generated by the oscillating unit are used. In ultrasonic cutting, mechanical, high-frequency vibration energy is transmitted to a cutting tool, for example via a linearly excited vibration system.

For this purpose, an alternating voltage generated by a generator is transmitted at an ultrasonic frequency to a vibration system. The oscillating system may consist of a converter, a booster or amplitude transformation piece and a sonotrode. In the converter is usually converted by the use of piezoceramics electrical energy into mechanical energy. The vibration is passed on to the sonotrode. The sonotrode, also due to its geometric design, converts the output amplitude of the converter or amplitude transformation piece into a working amplitude.

The sonotrode is brought into contact with the material to be separated with a cutting tool, for example a blade or a knife. The cutting tool can be made in one piece with the sonotrode. The tool usually includes a cutting end which wears down. Preferably, therefore, the tool can be mounted as a separate part of the sonotrode, it can for Example be screwed on. The tool can then be replaced as a wear part.

For example, an axial screw connection can be provided, as used for example in EP 0277823 A1 is shown. There must be a thread on the cutting tool. For this usually a different material is necessary than for the actual blade or the actual knife. The cutting tool must be made of two different materials, and moreover usually the thread material is heavier than the actual tool material.

Another possibility for fastening is to attach a slot to the freely oscillating end of the sonotrode into which a fastening end of a cutting tool is inserted. The cutting tool is fixed with a screw, which is guided transversely to the direction of insertion of the tool through the sonotrode. So that the tool is well secured, the attachment end either has a hole through which the screw can pass or at least one recess with which it can be brought up to the screw. The attachment end of the tool and the slot in the sonotrode can thereby be shaped so that a large part of the tool rests against the inner surface of the slot, as shown for example in FIG JP2000326291 (A ) is disclosed. However, the attachment end must form a significant part of the tool, resulting in an increased weight.

The publication JP 2010167535 (A ) shows a cutting tool in which the head of the fastening screw is sunk in the sonotrode. Lateral vibrations and noise can be avoided.

The position of the cutting tool in the sonotrode is limited in the known ultrasonic cutting devices essentially by the abutment of the attachment end to the screw and by the contact of the attachment end with the walls of the slot. However, this does not determine the position of the tool yet clearly. In addition, the cutting tool can slip out of the sonotrode, for example, in case of vibrations or in case of non-uniform loads or execute a rotary movement around the screw.

The JP2011-125972 and JP2000326291 (A ) show sonotrodes in which the slot has a tool shaft adapted to the recess so that the mounting end is mounted in the mounted state from all sides. The tool can then no longer rotate around the screw but still slip out of the slot unless the screw passes through a hole in the mounting end.

However, compared to the sonotrode, the tool has a significantly smaller width. For a knife with a desired cutting edge, therefore, a correspondingly wider sonotrode must be made available, which can adversely affect the mass to be moved.

It is an object to provide a cutting tool and an ultrasonic cutting device, which overcome the disadvantages of the known, and in particular ensure that there is no loosening and overheating of the cutting tool.

The object is achieved by a cutting tool for an ultrasonic cutting device. The cutting tool includes a cutting end and a mounting end for insertion into a Tool holder or a sonotrode. The cutting end is brought into contact with the workpiece to be cut in use. It may have a sharpened tip and / or one or more sharpened edges.

The cutting end and the attachment end may be made of different materials. Preferably, the cutting tool is in one piece and / or made of a material, such as hardened tool steel, tungsten carbide or tungsten.

The attachment end, in particular the entire cutting tool, is essentially designed as a blade. That is, the attachment end has a body having a smaller extent in one direction than in the directions perpendicular thereto. In a longitudinal direction connecting the cutting end and the attachment end, and in a width direction perpendicular thereto, the attachment end has a larger extent than in a thickness direction perpendicular to these directions. The length and width are thus greater than the thickness of the cutting tool.

In use, the cutting tool preferably performs linear oscillation in the longitudinal direction.

According to the invention, at least one positive-fit block facing away from at least one blade surface of the attachment end is arranged at the attachment end of the cutting tool. The positive locking block points in particular in the direction of the smallest extension of the attachment ends. Preferably, at least one interlocking block is provided on both sides. The form-fitting blocks extend in particular from the opposite leaf surfaces.

Preferably, exactly one interlocking block is provided on a sheet surface. However, it can also be arranged a number of form-fitting blocks on a sheet surface.

The interlocking block can interact with a complementary positive connection opening. While usually the cutting tool is fastened only by means of a clamp or screw connection, the interlocking block provides an additional safeguard, which can prevent, for example, the cutting tool from churning and slipping out of the socket on a tool holder or a sonotrode and / or rotating with respect to the socket ,

The form-fitting block has in particular a shock surface, with a directional component in the longitudinal direction.

The interlocking block is located at the attachment end, in an area where typically clamping forces act on the cutting tool anyway. The vibration of the cutting tool is therefore not disturbed.

In an advantageous embodiment, the at least one positive locking block extends over the entire width of the blade surface. In interaction with a complementary form-fit opening so twisting the Schneidzeugzeugs can be prevented. If the interlocking block has a substantially constant cross section across the width, then the mass of the interlocking block is also distributed uniformly over the width of the cutting tool.

Advantageously, the at least one positive locking block extends in a direction perpendicular to the longitudinal direction, which connects the cutting end and the attachment end. The Positive locking block can then prevent slipping and turning the cutting tool. The cutting tool can also be pushed laterally in a direction perpendicular to the longitudinal direction in a corresponding receptacle on a tool holder or in a sonotrode.

When inserting the cutting tool takes a clear position, so there is a self-centering.

Once a position has been selected, it is maintained under stress, leaving only a minimal risk of fatigue failure. Likewise, the tight fit prevents unwanted overheating, which could lead to premature wear of the cutting tool and could have a negative thermal impact on the clippings.

The tight fit also allows cutting with higher amplitudes.

Obtaining the tight fit with a positive locking block is an easy to implement measure and typically does not require higher production costs, since the formation of the positive locking block can be achieved depending on the profile without much effort.

The at least one interlocking block may have a bevel at the edge, which facilitates insertion of the cutting tool into a receptacle.

Forming blocks can be arranged mirror-symmetrically to each other. In particular, two positively locking blocks arranged on opposite leaf surfaces can be mirror-symmetrical to each other. In particular, the entire cutting tool is formed with mirror symmetry except for the cutting end.

The mirror symmetry exists with respect to at least one plane that is parallel to the longitudinal direction, that is, the direction connecting the cutting end and the attachment end.

Preferably, the mirror symmetry with respect to two mutually perpendicular planes, wherein one of the mirror planes is parallel to the longitudinal direction and the width direction and one of the mirror planes is parallel to the longitudinal direction and the thickness direction.

This results in a favorable mass distribution for longitudinal vibrations and the risk of transversal vibrations is minimized.

Preferably, the at least one positive locking block has a trapezoidal cross section.

The cross-section preferably results in a plane along the longitudinal direction, which connects the free end and the attachment end, and preferably perpendicular to the width direction, ie in a plane parallel to the thickness direction, in which the attachment end preferably has the smallest extent.

In particular, the longer baseline abuts the leaf surface and the shorter baseline points away from the leaf surface.

The cross section preferably has the shape of an isosceles trapezium.

In particular, the legs of the trapezium with the leaf surface form an angle of 90 ° or 45 °.

The cutting tool can then be made without much effort.

In an advantageous embodiment of the cutting tool, a recess is provided at the end of the attachment end, which has in particular in the longitudinal direction. This allows the cutting tool to be brought close to a fastening screw in a sonotrode or in a tool holder. The recess has, for example, a round contour in order to adapt to the round diameter of the screw. Both sides of the recess remain clamping surfaces.

The length of the cutting tool is for example between 20 and 30 mm.

The width of the cutting tool is for example 7-12 mm.

The thickness of the cutting tool is for example 0.05-3mm.

The at least one positive locking block extends, for example, 1-3 mm away from the blade surface.

In an advantageous embodiment, the width and / or the thickness of the cutting tool tapers at the transition from the attachment end to the cutting end, preferably the width by 0.5-1 mm and / or the thickness by 0.25-0.45 mm.

The object is also achieved by an ultrasonic cutting device with a sonotrode and a cutting tool, in particular as described above.

The cutting tool includes a cutting end and a mounting end.

The sonotrode has at least one screw hole which serves to receive a screw for fixing the cutting tool to the sonotrode.

From the attachment end of the cutting tool, at least one interlocking block extends away and at the sonotrode at least one complementary form-fitting recess is provided. The interlocking block forms a positive connection with the form-fitting recess when the cutting tool is mounted in the sonotrode. The positive connection acts at least in a longitudinal direction which connects the cutting end and the attachment end.

The positive locking block has, in particular, a stop surface with a direction component in the longitudinal direction, and the positive connection opening has, in particular, a stop surface complementary thereto.

While the screw causes a hold or jamming, the interlocking connection clearly defines the position of the cutting tool in the sonotrode, at least with respect to the longitudinal direction. Preferably, the interlocking block and the form-fitting recess are formed so that a relative angular alignment between the sonotrode and cutting tool with respect to the screw axis is set. For this purpose, positive locking block and the form-fitting recess extend, for example, in a direction perpendicular to the longitudinal direction.

The sonotrode may have a contact surface on which the cutting tool is applied and fixed with a screw.

In a preferred embodiment of the invention, the sonotrode has at one end two legs which form a slot into which the attachment end of the cutting tool can be inserted.

In the legs screw holes are arranged for receiving a screw which provides a clamping force of the legs.

On the inner sides of the legs of the sonotrode the at least one complementary form-fitting recess is provided.

In this embodiment, sonotrode and cutting tools form a symmetrical arrangement. The attachment end of the cutting tool is bordered by the legs of the sonotrode.

In an advantageous embodiment, the attachment end, in particular the entire cutting tool, is designed essentially as a blade. Forming blocks preferably extend from the sheet surfaces on both sides, which further preferably have a trapezoidal cross section, as described above. On the inner sides of the legs are complementary positive openings.

The slot in the sonotrode is then formed as symmetrical as the attachment end of the cutting tool, which has a favorable effect on the stability of the linear oscillations.

Advantageously, the slot at the fixed end of the legs on a widening. The length and width of the expansion determines the flexibility of the legs. These are on the one hand allow easy insertion of the cutting tool, on the other hand allow a reliable clamping force can be applied by the screw. The expansion preferably has a rounded inner contour to prevent notches.

At the free ends of the legs have on the inside abutment surfaces on which the blade surface of the cutting tool can rest.

One of the legs may have less mass than the other leg. In particular, the lighter leg on the outside of a flattening, so that the contact surface and the contact between the cutting tool and sonotrode is not affected.

The mass difference preferably contributes to the compensation of the weight of the screw head, so that the longitudinal vibration is not disturbed by the asymmetry of a fastening screw which has a thread and a generally thickened head.

A leg may have a screw hole with a screw head countersink. The screw head depression contributes to the mass reduction and also compensates for at least a part of the weight of the screw head.

In particular, the screw hole is provided with screw head depression on a lighter leg. The screw head can then be partially sunk, so that even a remainder of the head protrudes with an outer attack surface for a tool from the sonotrode.

Preferably, at least one screw hole has an internal thread. There is thus no nut necessary for fastening the screw. Preferably, there is only one thread in the screw hole on a heavier leg. A screw hole on a heavy one Leg serves to hold the screw, a screw hole on a lighter leg for applying and / or sinking the screw head.

In an advantageous embodiment of the ultrasonic cutting device, the positive locking block and the form-locking recess extend in a direction perpendicular to the longitudinal direction, so that the cutting tool can be inserted laterally into the sonotrode.

Preferably, the ultrasonic cutting device comprises a screw for insertion into the screw holes and for generating a clamping force between the legs. The screw has in particular a head, which preferably has a recess.

Advantageously, the head is tapered, in particular conical executed. The screw can then take a firm seat in the screw hole, whereby friction and thus heat development is largely prevented.

The screw also preferably has a cylindrical portion which serves for optimum positioning.

The invention will be explained below with reference to examples shown in FIGS.

Fig. 1

ein Schneidwerkzeug in perspektivischer Ansicht;

Fig. 2

das Schneidwerkzeug in einer ersten Draufsicht;

Fig. 3

das Schneidwerkzeug in einer zweiten Draufsicht;

Fig. 4

ein Befestigungsende in einer Schnittansicht;

Fig. 5

eine Ultraschallschneidvorrichtung in perspektivischer Ansicht;

Fig. 6

ein freies Ende einer Sonotrode in einer ersten Draufsicht;

Fig. 7

das freie Ende der Sonotrode in einer Schnittansicht;

Fig. 8

eine Befestigungsschraube in Schnittansicht.

Show it:

Fig. 1

a cutting tool in perspective view;

Fig. 2

the cutting tool in a first plan view;

Fig. 3

the cutting tool in a second plan view;

Fig. 4

an attachment end in a sectional view;

Fig. 5

an ultrasonic cutting device in a perspective view;

Fig. 6

a free end of a sonotrode in a first plan view;

Fig. 7

the free end of the sonotrode in a sectional view;

Fig. 8

a fastening screw in sectional view.

FIG. 1 shows a cutting tool 1 for an ultrasonic cutting device 10 (see FIG. 5 ) in perspective view.

The cutting tool 1 comprises a cutting end 2 and a fixing end 3 for insertion into a tool holder or a sonotrode 11 (see FIG FIG. 5 ).

The cutting tool 1 is designed essentially as a blade, wherein the dimensions in the longitudinal direction 25 which connects the cutting end 2 and a fastening end 3 and the width direction 26 perpendicular thereto are greater than the thickness 29 in a thickness direction 27 perpendicular to both directions 25, 26 ,

At the attachment end 3 of the cutting tool 1 8 groundbreaking form-locking blocks 4 are arranged by the opposite blade surfaces.

At the end of the fastening end 3 facing away from the cutting end 2, a recess 7 is provided, so that the cutting tool is close to a fastening screw 15 (see FIG FIG. 5 ) can be pushed.

FIG. 2 shows the cutting tool 1 in a first plan view perpendicular to the width direction 26 (see FIG. 1 ).

The positive locking blocks 4 are arranged mirror-symmetrically to each other. Except for the cutting end 2, the entire cutting tool 1 is mirror-symmetrical with respect to a plane 5 which is parallel to the direction 25 which connects the cutting end 2 and the attachment end 3.

The thickness 29 of the cutting tool 1 tapers at a transition 31 from the attachment end 3 to the cutting end 2.

The length 35 of the cutting tool 1 is for example 20 to 30 mm.

The maximum thickness 29 of the cutting tool 1 is for example 0.05 to 3 mm.

FIG. 3 shows the cutting tool 1 in a second plan view. The interlocking blocks 4 extend over the entire width 30 of the sheet surface 8. At the edges are bevels 33, which are the insertion of the positive locking blocks 4 in the Formschlussausnehmungen 17 (see FIG. 5 ) facilitate.

The width of the cutting tool 1 tapers at the transition 31 from the attachment end 3 to the cutting end 2.

The maximum width 30 of the cutting tool (1) is 7 to 12 mm.

FIG. 4 shows a mounting end 3 in a sectional view. The symmetrically arranged positive locking blocks 4 each have a cross section 6 in the form of a trapezoid. One side edge 9 defines the direction of an impact surface 28 (see FIG. 3 ) with a component which points in the longitudinal direction 25. In cooperation with a complementary surface not shown in the figure creates a positive connection, which prevents slipping and twisting of the cutting tool.

FIG. 5 shows an ultrasonic cutting device 10 in a perspective view. The ultrasonic cutting apparatus 10 includes a cutting tool 1 as shown in FIGS Figures 1-4 is shown and a sonotrode 11.

For fixing the cutting tool 1, a screw 15 is provided.

The form-fitting blocks 4 of the cutting tool form a positive connection with complementary form-fitting recesses 17 on the sonotrode 11.

The sonotrode 11 has at one end two legs 12a, 12b, which form a slot 13, in which the attachment end 3 of the cutting tool 1 in a insertion direction 34, which corresponds to the width direction 26 (see FIG. 1 ), is insertable.

FIG. 6 shows a free end of a sonotrode 11 in a first plan view.

The positive engagement recesses 17 are provided on the inner sides 16 of the legs 12a, 12b.

The slot 13 has at the fixed ends of the legs 12a, 12b an expansion 18, which has a rounded inner contour 19.

One of the legs 12a has on the outer side a flattening 20, and thus has less mass than the other leg 12b. With a screw inserted 15 (siege FIG. 5 ) so the weight of the screw head 23 (see FIG. 8 ) compensated.

FIG. 7 shows the free end of the sonotrode 11 in a sectional view.

In the legs 12a, 12b screw holes 14a, 14b are arranged for receiving a screw 15 (see FIG. 5 ), which provides a clamping force of the legs 12a, 12b.

In the leg 12a, which has less mass due to the flattening 20, a conical screw head countersink 21 is additionally provided, which merges into a cylindrically shaped recess 36. The shape of the screw hole 14a allows accurate centering and positioning of the screw.

The screw hole 14b on the heavier leg 12b has an internal thread 22.

FIG. 8 shows a fastening screw 15 in a sectional view. The screw 15 has a head 23 in which a recess 24 is provided. At the end of the fastening screw 15, which is opposite the head 23, an external thread 31 is provided. The screw 15 has a conically shaped portion 37, which merges into a cylindrical portion 38. The screw 15 can thus be well centered and positioned.

Claims (16)

Cutting tool (1) for an ultrasonic cutting device (10), wherein the cutting tool (1) comprises a cutting end (2) and a fixing end (3) for insertion into a tool holder or sonotrode (11),
characterized in that
the attachment end (3), in particular the entire cutting tool, is designed essentially as a blade and at least one positive-locking block (4) pointing away from at least one blade surface (8) of the attachment end (3) is arranged on the attachment end (3) of the cutting tool (1); preferably on both sides each a positive locking block (4). Cutting tool according to claim 1, wherein the at least one positive locking block (4) extends over the entire width (30) of the blade surface (8). A cutting tool according to claim 1 or 2, wherein the at least one positive locking block (4) extends in a direction perpendicular to the longitudinal direction (25) connecting the cutting end (2) and the attachment end (3). Cutting tool according to claim 1, 2 or 3, wherein positive locking blocks (4) are arranged mirror-symmetrically to each other, in particular the cutting tool (1) is formed mirror-symmetrical except for the cutting end (2). Cutting tool according to one of the preceding claims, wherein the positive locking blocks (4) have a trapezoidal cross-section (6). Cutting tool according to one of the preceding claims, wherein a recess (7) is provided at the end of the attachment end (3) facing away from the cutting end (2). Cutting tool according to one of the preceding claims, wherein the width (30) and / or the thickness (29) of the cutting tool (1) at a transition (31) from the mounting end (3) to the cutting end (2) tapers. Ultrasonic cutting device comprising a sonotrode (11) and a cutting tool (1), in particular according to one of claims 1-7, wherein the cutting tool (1) comprises a cutting end (2) and a fixing end (3), wherein the sonotrode (11) at least one Screw hole (14a, 14b) for receiving a screw (15) for fixing the cutting tool to the sonotrode (11),
characterized in that at least one positive locking block (4) extends away from the attachment end (3) of the cutting tool (1) and at least one complementary positive engagement recess (17) is provided on the sonotrode (10) so that the positive locking block (4) engages with the positive engagement recess (16). 17) forms a positive locking at least in a longitudinal direction (12) connecting the cutting end (2) and the attachment end (3) when the cutting tool (1) is mounted in the sonotrode (11). Ultrasonic cutting device according to claim 8, wherein the sonotrode (11) has at one end two legs (12a, 12b) forming a slot (13) into which the attachment end (3) of the cutting tool (1) can be inserted, and wherein Legs (14a, 14b) are arranged for receiving a screw (15), which provides a clamping force of the legs (12a, 12b), and wherein the at least one complementary form-fitting recess (17) is provided on the inner sides (16) of the legs (12a, 12b) of the sonotrode (10). Ultrasonic cutting device according to claim 8 or 9, wherein the attachment end, in particular the entire cutting tool, is designed substantially as a sheet and preferably on both sides of the sheet surfaces form-fitting blocks (4) wegerstrecken. Ultrasonic cutting device according to claim 9 or 10, wherein the slot (13) at the fixed ends of the legs (12a, 12b) has a widening (18), preferably with a rounded inner contour (19). Ultrasonic cutting device according to one of claims 9 to 11, wherein one of the legs (12a) has less mass than the other leg, in particular on the outside a flattening (20), Ultrasonic cutting device according to one of claims 9 to 12, wherein the screw hole (14a) on one leg has a, in particular conical, screw head countersink (21) and / or a cylindrical recess (36), in particular the screw hole (14a) on a lighter leg (12a ). Ultrasonic cutting device according to one of claims 9 to 14, wherein at least one screw hole (14b) has an internal thread (22), preferably the screw hole (14b) on a heavier leg (12b). Ultrasonic cutting device according to one of claims 9 to 15, wherein the positive locking block (4) and the form-fitting recess (17) extend in a direction (26) perpendicular to the longitudinal direction (25), so that the cutting tool (1) laterally into the sonotrode (11) can be inserted. Ultrasonic cutting device according to one of claims 9 to 16, wherein the ultrasonic cutting device (10) comprises a screw (15) for insertion into the screw holes (14a, 14b) and for generating a clamping force between the legs (12a, 12b), in particular a screw (15). 15) with head (23), which preferably has a recess (24), wherein the screw in particular has a conical region (37) which merges into a cylindrical region (38).

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