Toolholder and cutting tool

A toolholder has a plurality of receptacles for at least one respective cutting insert. For each receptacle, the toolholder comprises a clamping element associated with the receptacle and a hydraulic channel associated with the corresponding clamping element. Each clamping element is hydraulically adjustable between a closed position and an opened position via the associated hydraulic channel. Furthermore, the toolholder is configured such that the clamping elements in the closed position clamp the associated cutting inserts into the corresponding receptacle for the cutting operation and thus fix them to the toolholder and release them in the opened position so that the cutting inserts can be detached from the toolholder, in particular in a tool-free manner. Furthermore, a cutting tool is provided having a toolholder according to any one of the preceding claims and at least one cutting insert.

RELATED APPLICATION DATA

The present application claims priority pursuant to 35 U.S.C. § 119(a) to German Patent Application Number 102022111974.2 filed May 12, 2022 which is incorporated herein by reference in its entirety.

FIELD

The invention relates to a toolholder having a plurality of receptacles for a respective cutting insert, wherein for each receptacle the toolholder comprises a clamping element associated with the receptacle. The invention further relates to a cutting tool having such a toolholder and at least one cutting insert.

BACKGROUND

Such toolholders as well as cutting tools having such a toolholder are known.

The toolholders comprise a plurality of receptacles in which cutting inserts can be mounted for the cutting operation. Thus, the cutting inserts can be individually replaced when worn. Typically, these cutting inserts are clamped in the receptacles by means of clamping elements, for example by means of tensioning screws, which push and thus fix the cutting inserts against the receptacle.

A disadvantage with these toolholders is the number of tensioning screws that need to be tightened or loosened in order to secure or replace the cutting inserts.

The problem addressed by the invention is to provide a toolholder as well as a cutting tool having such a toolholder, to which cutting inserts can be fastened and replaced with little effort.

SUMMARY

The problem is solved by a toolholder having a plurality of receptacles for at least one respective cutting insert. For each receptacle, the toolholder comprises a clamping element associated with the receptacle and a hydraulic channel associated with the corresponding clamping element. Each clamping element is hydraulically adjustable between a closed position and an opened position via the associated hydraulic channel. Furthermore, the toolholder is configured such that the clamping elements in the closed position clamp the associated cutting inserts into the corresponding receptacle for the cutting operation and thus fix them to the toolholder and release them in the opened position so that the cutting inserts can be detached from the toolholder, in particular in a tool-free manner.

According to the present invention, it has been found that, compared to tensioning screws that individually must be tightened or loosened with a wrench or screwdriver, hydraulically adjustable clamping elements are reliably adjustable between a closed position and an opened position with little effort. For this purpose, only the pressure in the corresponding hydraulic channel must be adjusted to a value that corresponds to the closed position or the opened position. By releasing the cutting inserts in the opened position, as a result of which they are no longer fastened, in particular no longer rigidly fastened, the cutting inserts can be removed from the receptacles with low force, for example by hand. In other words, the cutting inserts are loosely connected to the toolholder so that no tool is required in order to separate the cutting inserts from the toolholder. In particular, the cutting inserts are not connected to the toolholder in a wedged or self-inhibited manner in the opened position, so that they would have to be released from the toolholder with great force, for example by means of a hammer.

In one embodiment, the hydraulic channels are part of a hydraulic system and are fluidly connected to one another. In this way, all clamping elements can be adjusted simultaneously or in parallel by setting the pressure inside the hydraulic system to a corresponding value. Thus, all clamping elements are adjusted to the open or closed position together, thus clamping or releasing all cutting inserts together, thereby further reducing the cost of fastening or replacing the cutting inserts.

The toolholder can have a filling opening for filling the hydraulic system. The filling opening is arranged on a front face of the toolholder, which is provided so as to oppose a prime mover when the toolholder is mounted to the prime mover for the cutting operation. In the mounted position, the front face is thus at least partially obscured by the prime mover, and the filling opening is arranged in a location that is not accessible or difficult to access. In this way, it can be reliably prevented that the hydraulic fluid is supplied to or removed from the hydraulic system via the filling opening when the toolholder is fastened to the prime mover. Thus, the operational safety is increased.

In a further embodiment, the toolholder has an adjustment element by means of which the pressure of the hydraulic system can be adjusted. This design has the advantage that the pressure inside the hydraulic system can be effectively and precisely adjusted via the adjustment element.

Here, it can be provided that the adjustment element can be adjusted between a first position in which the clamping elements are in the opened position and a second position in which the clamping elements are in the closed position. Thus, the clamping elements can be adjusted together via the adjustment element with little effort between the opened position and the closed position.

Additionally, or alternatively, the adjustment element can be arranged on a side of the toolholder that is provided so as to not oppose a prime mover when the toolholder is mounted on the prime mover for the cutting operation. In the mounted position, the side with the adjustment element is thus not obscured by the prime mover and is therefore easily accessible. In this way, the cutting inserts can be clamped or released via the adjustment element without the need to disassemble the toolholder from the prime mover. Thus, it is possible to replace cutting inserts with little effort even when the toolholder is mounted on the prime mover for the cutting operation.

According to one embodiment, the clamping elements are plungers, each of which is slidably supported in a cylinder recess. This design has the advantage that the clamping elements are reliably and precisely hydraulically adjustable between the closed position and the opened position.

Further, for each clamping element, the toolholder can comprise a resetting element associated with the corresponding clamping element, which biases the associated clamping element into the opened position or the closed position, depending on which position is desired as the home position. Thus, it is ensured that the clamping element is pushed by the resetting element into the opened position or the closed position, respectively, when the hydraulic pressure is less than the spring force.

According to a further embodiment, the toolholder is manufactured by means of an additive manufacturing process, in particular by means of a 3D printing process. In this way, the toolholder can be manufactured with little effort. In particular, the internal hydraulic channels can be efficiently formed using this manufacturing process.

According to the invention, a cutting tool with a toolholder according to the invention having the aforementioned advantages and at least one cutting insert is also provided in order to solve the aforementioned problem.

DETAILED DESCRIPTION

InFIG.1, a cutting tool10is shown with a toolholder20and a plurality of cutting inserts22, each arranged in a receptacle24of the toolholder20.

The toolholder20is manufactured by means of an additive manufacturing process, for example by means of a 3D printing process.

In the illustrated embodiment, the cutting tool10is a turntable mill having six receptacles24(seeFIG.2) for six respective cutting inserts22and an axis of rotation R about which the turntable mill rotates in the cutting operation.

Generally, the cutting tool10can be any cutting tool, in particular any rotating cutting tool.

Additionally or alternatively, in an alternative embodiment, the cutting tool10can comprise any number of receptacles24, but at least two.

The cutting inserts22each have a cutting body26(seeFIG.5), which is configured for machining a workpiece, and a tensioning element28, by means of which the cutting body26is fastened to the toolholder20.

To fasten the cutting inserts22, the toolholder20has six clamping elements30, each associated with a respective receptacle24and configured so as to clamp the tensioning element28arranged in the corresponding receptacle24, as will be explained in further detail below.

In an alternative embodiment, more than one cutting insert22can be arranged in each receptacle24, which can be clamped together for fastening by the clamping element30associated with the receptacle24.

The cutting inserts26in the present embodiment are indexable inserts, and the tensioning elements28are tensioning bolts.

In principle, the cutting body26and the tensioning elements28can each be designed as desired.

In an alternative embodiment, the cutting inserts22do not have separate tensioning elements28. In this case, the clamping elements30are respectively configured so as to clamp the corresponding cutting body26directly or via an integral piece in the associated receptacle24with a clamping element28connected to the cutting body26.

The clamping elements30are each part of a clamping mechanism32that is associated with the corresponding receptacle24and hydraulically actuatable.

For this purpose, the toolholder20comprises a hydraulic system34having a preferably annular reservoir36(seeFIG.3), as well as six hydraulic channels38, each associated with a clamping mechanism32and fluidly connected to the reservoir36.

In operation, the hydraulic system34is filled with a hydraulic fluid that can be supplied to or removed from the hydraulic system34via a filling opening40(seeFIG.2).

The filling opening40is arranged on a front face42of the toolholder20, which opposes a prime mover (not shown) when the toolholder20is fastened to the prime mover for the cutting operation.

Furthermore, the hydraulic system34has an adjustment channel44(seeFIG.4) extending from the reservoir36to a circumferential side46of the toolholder20and in which an adjustment element48of the toolholder20is arranged.

In the present embodiment, the adjustment element48is a compression screw, which can be screwed into the adjustment channel44in an adjustment direction S, in order to increase the force with which the adjustment element48presses on the hydraulic fluid in the hydraulic system34, and thus to increase the pressure in the hydraulic system34, or which can be released counter to the adjustment direction S, in order to reduce the force with which the adjustment element48presses on the hydraulic fluid in the hydraulic system34, and thus to lower the pressure in hydraulic system34.

Unlike the front face42, the circumferential side46does not lie opposite the prime mover when the toolholder20is fastened to the prime mover for the cutting operation. Thus, the adjustment element48is also accessible on the prime mover in the assembled state of the toolholder20.

The clamping mechanisms32are designed so as to be substantially identical to one another. Thus, the construction and function of the clamping mechanisms32will be exemplified below using a clamping mechanism32and with reference toFIGS.5and6.

The clamping mechanism32has a cylinder recess50in which the clamping element30is axially slidably supported and opens into the receptacle24with one axial end.

At the opposite axial end, the cylinder recess50is closed by a plug52.

Between the plug52and the clamping element30, a biasing element54is arranged in the form of a spiral spring, which elastically biases the clamping element towards the receptacle24.

The hydraulic channel38associated with the clamping mechanism32opens into the cylinder recess50and is configured so as to hydraulically adjust the clamping element30in the axial direction.

In order to ensure that hydraulic fluid remains in the hydraulic system34during operation and does not escape into receptacle24via the cylinder recess50, the clamping mechanism32can comprise a sealing device, such as a piston washer.

In this context, the clamping element30forms a plunger that can be adjusted between a closed position (seeFIG.5), in which an axial end56of the clamping element30projects into the receptacle24and clamps the cutting insert22in the receptacle24, and an opened position (seeFIG.6) in which the clamping element30releases the cutting insert22so that it can be removed from the receptacle24and thus separated from the toolholder20.

In the present embodiment, the closed position is defined by a low pressure level in the hydraulic system34, such that the spring force of the resetting element54is sufficient in order to press the clamping element30against the cutting insert22in the receptacle24counter to the hydraulic pressure.

The axial end56engages with a notch58in the tensioning element28and thus abuts the tensioning element28, whereby the cutting insert22is reliably clamped and fixed to the toolholder20.

The opened position is defined by a high pressure level in the hydraulic system34, which is large enough for the clamping element30to compress the resetting element54and thus be adjusted towards the plug52.

In order to prevent the cutting insert22from falling out of the receptacle24in the opened position due to its own weight, the toolholder20comprises a retaining device60associated with the receptacle24, which holds the cutting insert22in the receptacle24under a bias.

For this purpose, the retaining device60has a pressure piece62in the form of a ball and an elastic element64in the form of a spiral spring, which pushes the pressure piece62against the cutting insert22with low pressure.

The tensioning element28here has a position notch66, with which the pressure piece62can engage in order to keep the tensioning element28in a defined position.

The position notch66is preferably positioned such that the tensioning element28is arranged in the receptacle24when the pressure piece62engages with the position notch66, such that the cutting insert22is reliably fixed when the clamping element30is adjusted from the opened position into the closed position.

In order to fasten the cutting inserts22to the toolholder20, the clamping elements30are initially adjusted together into the opened position in that the hydraulic pressure is increased by setting the adjustment element48to the high pressure level.

The position which the adjustment element48occupies in the opened position of the clamping elements30defines a first position of the adjustment element48.

Subsequently, the cutting inserts22are inserted into the receptacles24in which they are held in position by means of the retaining devices60.

Finally, the clamping elements30are adjusted together into the closed position, in that the hydraulic pressure is reduced by setting the adjustment element48to the low pressure level.

The position which the adjustment element48occupies in the closed position of the clamping elements30defines a second position of the adjustment element48.

In this way, all cutting inserts22are effectively clamped in the receptacles24and thus securely fastened to the toolholder20for the cutting operation.

In this context, it is advantageous to have a display associated with the adjustment element48which marks the first and second positions, such that the adjustment element48can be reliably set to these positions.

Additionally, or alternatively, the toolholder20can comprise a pressure display indicating the hydraulic pressure in the hydraulic system34, in particular the high pressure level and the low pressure level to which the opened or closed position is associated.

In order to separate the cutting inserts22from the toolholder20again, the clamping elements30are adjusted together to the opened position in that the adjustment element48is reset to the first position.

As a result, the cutting inserts22are no longer clamped in the receptacles24, but are merely held in the receptacles24by the retaining devices60such that the cutting inserts22can be removed from the receptacles24with little force by hand and thus without tools.

A cutting tool according to a second embodiment will now be described based onFIGS.7and8. For the components known from the above embodiment, the same reference numerals are used, and reference is made in this respect to the foregoing explanations.

By contrast to the embodiment shown inFIGS.5and6, in which the clamping elements30are in the opened position when the hydraulic pressure is at the high pressure level, and in the closed position when the hydraulic pressure is at the low pressure level, the clamping mechanisms32of the toolholder20are designed according to the second embodiment such that the clamping elements30are in the closed position when the hydraulic pressure is at the high pressure level and in the opened position when the hydraulic pressure is at the low pressure level.

The hydraulic channels38here respectively open into the cylinder recess50between the associated clamping element30and the plug52, such that the clamping element30is pushed towards the receptacle24by the hydraulic pressure.

In this context, the resetting elements54are arranged so as to bias the clamping elements30into the opened position.

In the present embodiment, the resetting elements54are arranged in receptacle24between a front face68of the tensioning element28and an opposing wall70of the receptacle24when the cutting inserts22are inserted into the receptacle24.

Thus, the resetting elements54push the tensioning element28away from the wall70and the clamping element30away from the receptacle24, respectively.

Furthermore, according to the second embodiment, the toolholder20has no retaining devices60.

Of course, according to an alternative embodiment, the toolholder20can have corresponding retaining devices60.

In all embodiments, in this manner, a toolholder20as well as a cutting tool10with a toolholder20is provided, to which cutting inserts22can be fastened and replaced with little effort.

The hydraulic system34ensures that all clamping elements30are reliably adjustable between the closed and the opened positions together via a single adjustment element48.

The invention is not limited to the embodiments shown. Individual features of one embodiment can in particular be combined as desired with features of other embodiments, in particular independently of the other features of the corresponding embodiments.

LIST OF REFERENCE NUMERALS