EP2148768B1 - Cutting tool with a supporting body - Google Patents

Abstract

The invention relates to a cutting tool with a supporting body and at least one receptacle (2), which is arranged in the supporting body (1), is openly formed to allow a cutting edge (3) of a cutting element (4) to pass through and in which the cutting element (4) is clamped in its seat by means of at least one clamping jaw (5). The object of the invention is to improve the cutting tool with respect to the cutting behaviour and cost-effectiveness. This object is achieved by the cutting jaw (5) being formed resiliently in the direction of the cutting element (4).

Description

The invention relates to a cutting tool with a support body according to the preamble of claim 1.

There are generic cutting elements are known in which in a support body in a trained recording a cutting element and a movable clamping jaws is arranged, wherein the clamping jaws clamps the cutting element in its seat via centrifugal forces. In such a cutting tool assembly and correct alignment of the cutting element and the disassembly is relatively expensive and there is a risk that the cutting element slips when the tool is stationary.

Furthermore, cutting tools are known in which by means of screwing a cutting element is mounted in a receptacle of a supporting body. It is important that the contact surfaces of the clamping jaws, cutting elements and the seat of the cutting elements are flat to ensure a uniform contact pressure. In such a cutting tool problems occur during regrinding, since reground cutting elements are inclined with respect to the seat, so that the contact pressure is reduced, especially in the region of the cutting edge of the cutting element.

The cutting edge then vibrates during the machining process, resulting in an unclean cut; In extreme cases, chips can penetrate between the seat and the cutting element. The same problem occurs when due to manufacturing tolerances no flat contact surfaces can be provided.

The generic EP 1 574 308 A1 relates to a milling tool which is held in a slot-like receptacle in a base body. A jaw clamps a cutting element in the body firmly. The jaw is clamped by a screw and has a contact surface which is inclined slightly in the direction of the cutting element. An angular range of approximately 1 ° is indicated.

The DE 11 95 934 B1 relates to a knife shaft for woodworking machines with wedge-shaped pressure bars. Clamping elements are movably mounted in a shaft body and press knife against the shaft body. The clamping elements are pressed by elastic means against the blades.

The DE 92 10 363 U1 describes a cutter head with a base body which is provided with at least two evenly distributed over its circumference arranged recesses, in which knife by means of a clamping device, which has at least one clamping element and at least one cooperating with this and the body clamping screw, are set interchangeable.

The BE 401 214 A1 relates to a knife shaft with a support body, in which recesses are arranged for receiving knives in the longitudinal extent of the blade shaft. In the cutting direction in front of the blades, a groove extending essentially parallel to the shaft axis is milled in the shaft body so that a part of the receptacle is formed only on a narrow web of the blade shaft. About a threaded rod, this surface is pressed against the cutting edge and clamped in the knife roller.

The EP 1 568 453 A1 describes a Ringzerspaner with knife elements, which are held by clamping retaining rails on the ring body.

The US 4,193,719 A describes a cutting tool with resharpenable cutting elements.

The object of the invention consists in an improvement of the cutting tool with respect to the Schnittverhaltans and the Wirtschaftlchkeit.

This object is achieved with a cutting tool having the features of claim 1.

Due to the resilient design of the clamping jaws in the direction of the cutting element, the cutting element in the region of the cutting edge is also firmly clamped in his seat when it comes due to a reworking of the cutting element or due to manufacturing tolerances to deviations in the flatness of the contact surfaces of the cutting element. It also compensates for inaccuracies that can occur when the cutting element is inserted obliquely or the support body already has deformations as a result of prolonged use. By the safe investment of the cutting element in the region of the cutting edge on the seat in the receptacle of the support body, the vibration behavior of the cutting element is positively influenced, so that a clean cut is made possible. Due to the possibility of re-sharpening of the cutting element, the tool costs are reduced, so that overall the efficiency of the cutting tool is increased,

The invention provides that the resilient configuration of the clamping jaw is achieved by a weakening of the clamping jaw on the side facing away from the cutting element. Likewise, the resilient configuration can also be adjusted by a suitable material selection or suitable component dimensioning.

A recess designed as a groove is formed in the clamping jaw on the side facing away from the cutting element, for example by a separation method or by a appropriate design during the original molding process. Of course, multiple weakenings or recesses may be provided in the jaw. Due to the weakening of the clamping jaw on the side facing away from the cutting element, an "elastic joint" is created, whereby the clamping jaws resiliently bears against the cutting element and presses this into its seat in the receptacle of the supporting body. Depending on the design or requirement profile of the clamping jaws or it is provided that one or more weakenings are provided, to increase the spring effect, the weakenings or recesses extend over the entire axial width of the jaws or. If a plurality of weakenings or recesses are provided, these are advantageously arranged substantially parallel to one another, however, the recesses or weakenings can also be adapted differently from a parallel orientation to adapt to certain cutting edge geometries or applications that cause a certain wear behavior. So z. B. in a Profilfräswerkzeug, in which areas of the cutting element are exposed to different loads to be responded to the different loads with a corresponding arrangement and orientation of the recesses or weakening in the jaws to achieve an adjustment of the contact force as a function of the respective load ,

In order to increase the spring action or to achieve a targeted adjustment of the spring action, a spring element is arranged in the weakening or recess, which loads the clamping jaws so that a bias of the clamping jaw takes place in the direction of the cutting edge of the cutting element. The spring element is preferably made of an elastic material or a compression spring and causes an expansion of the weakening or the recess, so that an increase in the spring force in the upper and lower end region of the clamping jaw occurs.

An inexpensive and effective embodiment of the recess or the weakening is a groove or a plurality of grooves which are incorporated in the clamping jaws. This groove can be adapted in shape and size to the particular application and easily incorporated by grinding or milling in the jaws. A corresponding configuration of the groove facilitates the arrangement of the spring element in the form of an elastic plastic or a compression spring, as is ensured by a corresponding cross-sectional design a secure attachment of the spring element to the clamping jaws in the groove.

A further embodiment provides that the clamping jaws is designed bent in the direction of the cutting element and consists of a metal or plastic piece. This bending acts as a kind of bias and supports the resilient effect on the cutting element, whereby an increase in the contact pressure is effected in particular in the region of the cutting edge of the cutting element.

In order to securely clamp and fix the cutting element in his seat, a screw connection of the clamping jaw is provided with the support body. About the screw also adjustability of the contact pressure is made possible in which the tightening torque of the screw can be varied and adjusted. Furthermore, different jaws can be used depending on the purpose, which is easy to implement by a detachable connection by means of screwing.

A development provides that on the clamping jaw in the direction of the cutting element, a projection is arranged, which engages in a corresponding recess of the cutting element. Alternatively, the projection may also be arranged on the cutting element and engage in a recess of the clamping jaw. The projection and the recess are for axial and radial securing of the cutting element trained and support the definition of the cutting element in the seat of the support body. In addition or as an alternative to the projection or the recess, an axial securing element for the cutting element is provided on the supporting body in order to prevent a lateral displacement of the cutting element.

Advantageously, it is for purposes of maintenance and adaptation to the material or to the workpiece to be machined replaceable the cutting element attached to the support body, which is facilitated in particular by a screw connection of the clamping jaw.

In addition to a resilient design of the clamping jaw in the direction of the cutting element is provided that a resilient formation of the clamping jaw takes place in the direction of the cutting edge in order to obtain an optimal clamping of the cutting element and a precise guidance of the cutting edge.

A development of the invention provides that in the cutting element an indicator recess, in particular an indicator groove is ground, indicating the end of a Nachschärfzone. This makes it possible to equip the cutting tool with a resharpenable cutting element. The goal is to be able to transfer a high clamping force to the cutting element despite decreasing material thickness with repeated resharpening. When using an elastic clamping jaw, only a precisely defined variation of the material thickness of the cutting element is permitted, since a sufficiently secure clamping of the cutting element and a sufficient precision in the adjustment of the cutting tool must be ensured. The permissible tolerances for the material thickness of the cutting element and thus for the depth of the Indikatorausnehmung are extremely low, so that due to the low tolerances Grinding a grinding in a Indikatorausnehmung, in particular an indicator groove, is an advantage.

Advantageously, the cutting tool is designed as a knife shaft or a knife head of a woodworking machine, however, it is possible to use this cutting tool for metal, plastic or stone processing.

Figur 1-

eine Schrägdraufsicht auf ein Schneidwerkzeug in Explosionsdarstellung;

Figur 2 -

eine Detailansicht der Figur 1 aus einem anderen Winkel;

Figur 3 -

eine Schnittdarstellung des Schneidwerkzeuges vor dem Zusammenbau;

Figur 4 -

eine Schnittdarstellung des montierten Schneidwerkzeuges,

Figuren 5A bis 10B -

verschiedene Ausführungen von Spannbacken in Schnittdarstellung und Schrägdraufsicht;

Figur 11 -

ein Schneidelement in Draufsicht;

Figuren 11a bis 11c -

ein Schneidelement gemäß Figur 11 in Seitenansicht; sowie

Figuren 12A bis 15B -

verschiedene Ausführungen von Spannbacken in Schnittdarstellung und Schrägdraufsicht.

Hereinafter, an embodiment of the invention will be described with reference to the accompanying drawings. Like reference numerals in different figures indicate like components. Show it:

Figure 1-

a sloping top view of a cutting tool in an exploded view;

FIG. 2 -

a detailed view of the FIG. 1 from another angle;

FIG. 3 -

a sectional view of the cutting tool prior to assembly;

FIG. 4 -

a sectional view of the mounted cutting tool,

FIGS. 5A to 10B

various versions of clamping jaws in sectional view and oblique top view;

FIG. 11

a cutting element in plan view;

FIGS. 11a to 11c

a cutting element according to FIG. 11 in side view; such as

FIGS. 12A to 15B

various versions of clamping jaws in sectional view and oblique top view.

The FIG. 1 shows a cutting tool with a support body 1 and a receptacle incorporated therein 2. The receptacle 2 may either be incorporated during the primary molding process of the support body 1 in the mold or subsequently by milling, grinding or another Machining methods are incorporated. The receptacle 2 serves as a seat for a cutting element 4, the cutting edge 3 extends radially outwardly from the support body 1 in the illustrated embodiment. In addition to a radially outwardly directed cutting edge 3, the cutting edge 3, z. B. at a vortex tool, extend radially inwards.

The cutting element 4 is inserted into its seat in the receptacle 2, wherein with respect to the seat, a clamping jaws 5 is arranged, which clamps the cutting element 4.

The clamping takes place by means of a screw 9 which engages through a through hole in the support body 1 in an incorporated into the clamping jaws 5 thread and clamps the cutting element 4 after application of a specified torque.

On the side facing away from the cutting element 4 side of the clamping jaw 5, a groove 6 is incorporated through which a weakening occurs due to the missing material, resulting in a joint effect in the region of the groove 6. In this groove 6, a compression spring 8 is inserted, which presses apart the parts of the clamping jaw 5 on both sides of the groove 6 and so causes a resilient contact of the clamping jaw 5 on the cutting element 4, in particular in the region of the cutting edge 3. The compression spring 8 is shown schematically in the embodiment and stands for all compression spring elements that can widen the groove 6. The clamping jaw 5 is biased and curved so that the radially outwardly or inwardly facing ends of the clamping jaw 5 are resiliently biased.

Also on the clamping jaw 5, a projection 10 is formed, which engages in a corresponding groove 11 in the cutting element 4 and in addition to the force applied by the screw 9 clamping force a positive locking against a radial displacement of the cutting element 4 due forms centrifugal forces. The arrangement and operation of an axial lock 12 will be explained with reference to the following figures.

In the FIG. 2 can be seen in an enlarged detail that the formed as a bolt axial securing element 12 is passed through a hole into the seat of the cutting element 4 in the receptacle 2. Next radially inward is the through hole for the screw 9, which engages in a thread of the clamping jaw 5 and the head forms a fuse for the axial securing element 12 after screwing. The clamping jaws 5 forms the other contact surface for the axial securing element 12, so that this is fixed in the assembled state. In the cutting element 4, a recess 16 is incorporated, which is formed corresponding to the axial securing element 12 and in the assembled state, the axial securing element 12 comprises. In this way, a displacement of the cutting element 4 in the axial direction is prevented.

Also in the FIG. 2 the formation of the groove 6 in the clamping jaws 5 and the pressure spring 8 arranged within the groove 6 becomes clear. The groove 6 extends over the entire axial width of the clamping jaw 5, so that over the entire width of the clamping jaw 5, a spring action in the direction of the cutting edge 3 of the cutting element 4 can be effected. The recess 11 within the cutting element 4 engages in the mounted state in the projection 10 of the clamping jaw 5 and prevents radial displacement of the cutting element 4 during operation of the cutting tool.

In the FIG. 3 the arrangement of the cutting element 4, the clamping jaw 5 and the support body 1 is clear, as well as the effect of arranged in the groove 6 compression spring 8. The compression spring 8 causes a widening of the groove 6 at the cutting element 4 facing away from the edges, as shown by the arrows D is shown. By this pressure are radially seen the outer and inner ends of the clamping jaw 5 bent or biased in the direction of the cutting element 4, as indicated by the arrows B. This bias can also be introduced in the course of the manufacturing process. While the radially inwardly directed end of the clamping jaw 5 is fixed by the screw 9 and a corresponding cutout within the support body 1, due to the resulting by the groove 6 joint-like weakening of the cutting edge 3 facing the end of the clamping jaw 5 in the direction of the cutting element 4, so that it comes to a resilient bias and a loading of the cutting element 4 in the region of the cutting edge 3 with an increased contact pressure. This makes it possible to rework or resharpen the replaceable shaped cutting element 4, without any resulting unevenness in the system on the seat within the support body 1 having a negative effect on the cutting behavior. Due to the resilient design and the increased contact pressure in the area of the cutting edge 3, unevenness, decreasing material thicknesses, material defects or an oblique seat within the receptacle 2 are compensated, whereby the necessary clamping force and desired cutting quality can be maintained over a long period of time.

Based on FIG. 4 In an assembled representation it is clear that the projection 10 of the clamping jaw 5 protects the cutting element 4 in the installed state against a radial displacement, while the axial securing element 12 prevents a displacement out of the plane of the drawing or into the plane of the drawing.

The receptacle 2 is formed at the radially inner end in such a way that a correspondingly shaped end of the clamping jaw 5 is easily pivoted, so that a rotation about this inner point is effected by the radially further outwardly disposed screw 9 and by means of the screw 9 applied tensile force , This way is a safe Clamping of the cutting element 4 ensured by the clamping jaws 5. The compression spring 8 presses the outer end of the clamping jaw 5 upwards and causes a rotation or bending of the upper portion of the clamping jaw 5 to the region of material weakening through the groove. 6

The FIGS. 5A to 10B show various representations of clamping jaws 5, wherein the marked by the reference numeral A in each case a sectional view and the figures designated by the reference numeral 8 are a sloping plan view. In the FIG. 5 is shown with a radially outwardly enlarged bevel 15 of the clamping jaw 5, with the corresponding after the installation of the clamping jaw 5 in the cutting tool a corresponding contact force on the cutting element 4 in the region of the cutting edge 3 is applied. The spring action of the clamping jaw 5 is effected by the reduction of the material in the radially outer end of the clamping jaw 5, so that a whip or leaf spring effect arises, through which an increase in the contact pressure force is achieved. Alternatively or additionally, the clamping jaw 5 can also be curved, in order in particular to increase the contact pressure on the inner and outer regions of the cutting element 4. The object of the FIG. 5 is not an embodiment of the invention.

In the FIGS. 6 and 7 grooves 6 or a groove 6 are milled into the clamping jaw 5 over its entire axial width, in which an elastic spring element, for example an elastic plastic 7 is incorporated in order to achieve a corresponding spring effect. In the FIG. 6 is the parallel arrangement of the grooves 6 to see, depending on the external conditions and the intended use, a correspondingly different orientation of the grooves 6 can be provided.

The FIGS. 8 and 9 show a clamping jaws 5 with grooves 6 and a groove 6, wherein in the groove 6 in the grooves 6 no spring element is inserted. The joint effect or the spring action and a corresponding bias of the clamping jaw 5 can be reinforced, for example, via a corresponding surface treatment and voltage conditions generated thereby within the clamping jaw 5.

The FIG. 10 shows in detail a jaw 5 according to the FIGS. 1 to 4 with a arranged within the groove 6, shown schematically compression spring 8, whose operation in the FIGS. 1 to 4 is explained.

In the FIG. 11 In plan view, a foot part of a cutting element 4 is shown with a recess 16 for receiving the axial securing element 12 without the cutting edge 3. In the cutting element 4 a Indikatorausnehmung 13 is ground in the form of a groove over the entire width of the cutting element 4 to indicate how far the cutting element 4 can be reground before the minimum material thickness is reached. Reprecipitation too often reduces the material thickness of the cutting element 4, which leads to a diminishing strength and problems with an exact and firm clamping in the cutting tool or support body 1 and impairs secure clamping by the clamping jaw 5.

In the FIG. 11a the cutting element 4 is shown with its original material thickness, in the FIG. 11b in an already maximum reground state, which can be seen at the different depth of the recess 11. The depth of the indicator groove 13 is the measure for the regrinding zone 14, within which regrinding can be carried out without danger. In the presentation of the FIG. 11b the end of the regrinding zone has been reached. The safe use of the knives is guaranteed as long as a difference in thickness of the knives in the area of the clamping surface and the indicator groove 13 can be seen. In the FIG. 11c the maximum re-sharpening zone is no longer detectable. These knives or cutting elements 4 could for the Clamping system have too small a knife thickness and may therefore no longer be used. The grinding in of the indicator groove 13 has the great advantage that an extraordinarily precise introduction of the recess or the groove 13 can take place. Alternatively to a configuration as a groove 13, the recess may also have a different shape. If similarly precise methods can be provided, the indicator groove 13 can also be introduced into the cutting element 4 in a different manner.

In the FIG. 12 a clamping jaws 5 is shown with a running over the entire width of the clamping jaws 5 groove 6, wherein the clamping jaws 5 at the same time has a chamfer 15, which leads to an increased elasticity and spring action. The groove 6 is formed with a rounded cross section, which opens in the direction of the clamping jaw surface and thus has a parabolic shape.

The FIG. 13 shows a similar construction of the jaw 5 as the FIG. 12 , but with a different contour of the groove 6, which is formed as a pitch circle, with a circumference of more than 180 °. As a result, an undercut is formed within the groove 6.

In the FIG. 14 is a variant of FIG. 9 shown, in which the radially outer region of the clamping jaw 5 is provided with a weakening by a part of the material of the clamping jaw 5 has been removed. Also, the contour of the recess or groove 6 differs from that of the FIG. 9 , The groove shape 6 corresponds to the groove shape of FIG. 12 ,

In the FIG. 15 is a jaw 5 without a spring element 8 according to the FIG. 10 shown. The recess 6 is not rounded, but executed at an angle. Instead of a rounded or formed by two bevels groove 6, this may also be polygonal. All jaws 5 point a threaded bore for receiving the bolt or the screw 9.

Claims (11)

1. A cutting tool with a supporting body (1) and at least one receptacle (2) which is arranged in the supporting body (1) and is designed to be open to allow a cutting edge (3) of a cutting element (4) to pass through and in which the cutting element (4) is clamped in its seat via at least one clamping jaw (5), whereby the clamping jaw (5) is designed to be elastic in the direction of the cutting element (4), the clamping jaw (5) is coupled to the supporting body (1) via a screwed connection (9) and clamps the cutting element (4), characterized in that the clamping jaw (5) has at least one weakened location or recess designed as a groove (6) on the side facing away from the cutting element (4).
2. The cutting tool as claimed in claim 1, characterized in that a plurality of weakened locations or recesses (6) are arranged substantially parallel to one another.
3. The cutting tool as claimed in claim 1 or 2, characterized in that the weakening location or recess (6) extends over the entire axial width of the clamping jaw (5).
4. The cutting tool as claimed in claim 1 or 3, characterized in that a spring element (7; 8) is arranged in the weakened location or recess (6).
5. The cutting tool as claimed in one of the preceding claims, characterized in that the clamping jaw (5) consists of a metal or plastic piece bent in the direction of the cutting element (4).
6. The cutting tool as claimed in one of the preceding claims, characterized in that at least one projection (10) is arranged on the clamping jaw (5) on the cutting-element side, said projection (10) engaging in a corresponding recess (11) in the cutting element (4) or that at least one projection is arranged on the cutting element (4) on the clamping-jaw side, said projection engaging in a corresponding recess in the clamping jaw (5).
7. The cutting tool as claimed in claim 6, characterized that the projection (10) and the recess (11) are designed for axially and/or radially locking the cutting element (4).
8. The cutting tool as claimed in one of the preceding claims, characterized by an axial locking element (12) arranged on the supporting body (1) for the cutting element (4).
9. The cutting tool as claimed in one of the preceding claims, characterized in that the clamping jaw (5) is designed to be elastic in the direction of the cutting edge (3).
10. The cutting tool as claimed in one of the preceding claims, characterized in that an indicating recess (13) which indicates the end of a regrinding zone (14) is ground in the cutting element (14).
11. The cutting tool as claimed in one of the preceding claims, designed as a cutter block or a cutter head of a woodworking machine.

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