Patent Description:
In the machine tool industry, particularly for cutting machine tools - for example, turning, blanking, milling and threading machine tools - it is widely known to use interchangeable tools that can be coupled to the same machine tool so as to provide flexibility of use and adaptability to different machining requirements of the machine tool.

In general, each such tool - also referred to as cartridges in the jargon - comprises a support body, a cutting element - also referred to as an insert in the jargon -, fastening elements - for example, screws and brackets - and any ancillary elements - for example, gaskets, underplates, etc..

A tool holder is provided for attaching the tool to the machine tool, which is attached to the machine tool and the tool, in order to ensure the correct positioning of the required tool and enable the desired machining of a workpiece.

The coupling between the tool and the tool holder is a critical aspect, as on the one hand it must be stable and reliable to ensure precise machining of workpieces, and on the other hand the assembly and disassembly of tools from the tool holder must be simple and quick to ensure effective replacement of tools or components thereof.

For this purpose, the Applicant presented a tool and tool holder pair provided with matching surfaces having complementary abutting elements. Such abutting elements allow the tool to be simply and accurately coupled to the tool holder and, in addition, allow a single screw to be used to obtain a stable and reliable attachment of the tool to the tool holder.

Despite the goodness of this solution, the Applicant has observed that the mechanical stresses to which the tool-holder unit is subjected can lead to accelerated wear of the tool components and the establishment of unwanted.

Document <CIT> describes a cutting tool according to the preamble of claim <NUM>.

It is an object of the present invention to overcome the drawbacks of the prior art.

In particular, it is an object of the present invention to provide a cutting tool that allows stable and reliable coupling to a corresponding tool holder. In particular, the tool is capable of withstanding mechanical stress for extended periods, remaining stable while machining a workpiece, and still allows for quick and easy replacement of the tool as needed.

It is a further object of the present invention to provide a cutting unit comprising one or more interchangeable tools and a universal tool holder, which can be easily and reliably coupled and uncoupled.

These and other objects of the present invention are achieved by means of a unit incorporating the features of the appended claims, which form an integral part of the present description.

According to a first aspect, the present invention is directed to a cutting tool, for example a turning, blanking, milling, and/or threading tool. The tool includes a cutting element configured to contact a body to be machined, and a support body configured to support the cutting element in a working position and to be coupled to a tool holder mounted on a processing machine.

In detail, the support body includes a first side surface configured to be coupled to a first surface of the tool holder, the first side surface comprising at least one abutting surface configured to be coupled to a complementary abutting surface of the first surface of the tool holder, and at least one fastening element configured to be coupled to a complementary fastening element included in the first surface of the tool holder to secure the tool to the tool holder.

Advantageously, the support body includes a second lateral surface configured to abut at least partially against a second surface of the tool holder. The second lateral surface is adjacent to the first lateral surface, and includes at least one portion inclined relative thereto.

The second side surface includes an abutting portion configured to abut against the second surface of the tool holder. The second lateral surface delimits an elastic element of the support body. In detail, the elastic element is configured to generate a resilient elastic force substantially orthogonal to the abutting portion when the abutting portion is abutting against the second surface of the tool holder.

With such a solution, it is possible to stabilize the tool against mechanical stresses due to workpiece machining operations. In other words, the second lateral surface allows the forces associated with machining vibrations to be unloaded onto the tool holder, thereby conferring greater stability to the tool and substantially reducing the stresses on the one or more fastening elements used to couple the tool to the tool holder. As a result, both an increase in tool life and improved machining accuracy of workpieces by the machine tool are achieved.

This structure also ensures optimal coupling between the second lateral surface of the tool body and the tool holder. In particular, the elasticity of the elastic element allows to compensate for machining tolerances that would limit the uniformity of the coupling of the second lateral surface of the tool body with a corresponding surface of the tool holder. In addition, the elastic element may be sized to exert a further cushioning function with respect to mechanical stresses to which the tool is subjected during operation of the machine tool.

Preferably, the abutting portion is consecutive to the inclined portion.

In one embodiment, the first lateral surface comprises two or more positioning elements configured to correspond to respective two or more complementary positioning elements formed on the first surface of the tool holder. Preferably, at least three of the coupling elements are arranged to delimit a triangular region of the first lateral surface. Even more preferably, at least part of the surface of the positioning elements defines the abutting surface of the lateral surface.

This ensures precise positioning of the tool with respect to the tool holder and thus to the machine tool and, at same time, a particularly stable coupling between the tool and the tool holder. This results in a particularly precise workpiece processing.

In one embodiment, the inclined portion of the second lateral surface and the first lateral surface define an angle α of less than <NUM>°, preferably less than <NUM>°, with respect to a plane orthogonal to both the first lateral surface and the second lateral surface.

Due to such a structure, it is always possible to ensure contact between the second lateral surface of the tool and the second lateral surface of the tool holder.

In one embodiment, the abutting portion may comprise a dampening element, for example, a deformable element - such as an O-ring - configured to abut against the tool holder.

In this way, adhesion between the tool and the tool holder can be improved.

In one embodiment, the second lateral surface is delimited by a free edge of the support body.

In addition, the elastic element of the support body is further delimited by a slot, referred to as slot, which develops:.

This conformation of the tool body allows the elastic element to be defined and, at same time, allows the tool to be highly robust. In addition, when the elastic element is subjected to a deformation force greater than a limiting value, the walls delimiting the slot come into contact with each other, with the effect of making the elastic element substantially integral with the rest of the tool support body thus ensuring the robustness and stability of the tool.

In one embodiment, the second lateral surface is conformed such that a free end thereof - being distal from the first lateral surface - is at a distance from the first lateral surface of between <NUM> and <NUM> times, preferably between <NUM> and <NUM> times, a length of the first lateral surface, both calculated in the plane orthogonal to both abutting surfaces.

This ratio allows to obtain a particularly robust and reliable structure.

In one embodiment, the slot has a length along a direction parallel to or inclined with respect to the inclined portion of the second lateral surface of between <NUM> and <NUM>, preferably <NUM> times the length of the second lateral surface calculated in the plane orthogonal to both the first lateral surface and the second lateral surface. Further, the slot preferably has a distance from the second lateral surface such that a thickness of the elastic element - calculated with respect to the orthogonal plane - is substantially constant or within an acceptable range of values throughout the extension of the slot within the body. Preferably, said range is between <NUM> and <NUM> times the length of the slot, even more preferably between <NUM> and <NUM> times the length of the slot, calculated in the plane orthogonal to both abutting surfaces.

In an alternative embodiment, said elastic element is a protruding appendage of the support body, said protruding appendage, projecting from the support body in a direction orthogonal or inclined to the first support surface, preferably, such that a free end of the appendage - being distal from the first lateral surface of the body - is at a distance from the first lateral surface of between <NUM> and <NUM> times, preferably between <NUM> and <NUM> times, a length of the first lateral surface where both the distance and the length are calculated in a plane orthogonal to both abutting surfaces.

Even more preferably, the appendage has a width of between <NUM> and <NUM> times, preferably between <NUM> and <NUM> times the distance between the free end of the appendage and the first lateral surface of the body calculated in the plane orthogonal to both abutting surfaces.

These conformations of the elastic element allow the tool to be stabilized in a manner similar to that described above. In addition, this conformation allows a mass of the tool support body to be reduced.

In one embodiment, the inclined portion of the second lateral surface is proximal to the first lateral surface. Further, the abutting portion is substantially orthogonal to the first lateral surface.

Due to this solution, it is possible to control and ensure a sufficient tool abutting surface, which can effectively distribute and transmit the mechanical stresses to which the tool is subjected.

In one embodiment, the second lateral surface includes a connecting portion adjacent to the first lateral surface and the inclined portion of the second lateral surface, said connecting portion being concave. Preferably, the connecting portion defines a circumferential arc profile with respect to a plane orthogonal to the first lateral surface and the second lateral surface.

In this way, it is possible to ensure an adequate coupling of the matching surfaces of the tool to the corresponding surfaces of the tool holder, in particular, which is not hindered by an edge between said surfaces of the tool holder. In addition, such a structure ensures effective deformation of the elastic element of the tool.

A different aspect of the present invention relates to a cutting unit, configured to be coupled to a machine tool. Said cutting unit comprises:.

In particular, the tool holder comprises:.

This cutting unit allows to obtain the above-mentioned advantages with reference to the cutting tool according to the present invention. Further, a plurality of tools having a support body with the above-mentioned features can be provided, with a cutting element suitable for performing different machining or cutting operations all of which are suitable for being coupled to the same tool holder.

Further characteristics and objects of the present invention will be more apparent from the following description.

The invention will be described below with reference to a few examples, provided for explanatory and non-limiting purposes and illustrated in the accompanying drawings. These drawings illustrate different aspects and embodiments of the present invention and, where appropriate, similar reference numerals illustrating similar structures, components, materials and/or elements in different figures are indicated by similar reference numerals.

While the invention is susceptible to various modifications and alternative constructions, certain preferred embodiments are shown in the drawings and will be described in detail below. It should be understood, however, that there is no intention to limit the invention to the specific embodiment described herein, but, in contrast, the invention is intended to cover all modifications, alternative constructions, and equivalents that fall within the scope of the invention as defined in the claims.

The use of "e.g.," "etc.," "or" means non-exclusive alternatives without limitation unless otherwise indicated. The use of "includes" means "includes, but not limited to" unless otherwise indicated.

Referring to <FIG>, there is described a tool <NUM>, also referred to as a 'cartridge', in accordance with one embodiment of the present invention.

In detail, the tool <NUM> includes a support body <NUM> on which a cutting element <NUM> is mounted also referred to by the term 'insert' in the jargon. In the example considered, the body <NUM> includes a housing <NUM> in which the cutting element <NUM> is inserted, preferably together with a spacer element <NUM>, also referred to as a 'subplate' in the jargon. Preferably, the cutting element <NUM> and the spacer element <NUM> are locked in position by a screw (not visible in the Figures) and, even more preferably, by a bracket <NUM>, which is in turn screwed to the body <NUM> by means of a screw <NUM>.

Advantageously, the housing is formed at one end of the body <NUM> and is conformed such that at least one portion of the cutting element <NUM> projects outwardly.

Preferably, the body <NUM> and the bracket <NUM> include one or more nozzles (four of which are visible in <FIG>) configured to emit a lubrication/cleaning fluid - for example, a jet of water - to the cutting element <NUM> so as to remove machining swarf and maintain a reduced temperature of the cutting element <NUM> that would otherwise become frictionally hot during machining.

The body <NUM> further includes a through-hole <NUM> configured to receive a fastening screw <NUM> - visible in <FIG> - for attachment to a tool holder - for example, the tool holder <NUM> illustrated in <FIG> and described below.

In detail, in order to allow coupling between tool <NUM> and tool holder <NUM>, the tool <NUM> is provided with a first lateral surface <NUM>, which is configured to be associated with a first lateral surface <NUM> of the tool holder <NUM> - as visible in <FIG>. The first lateral surface <NUM> is, preferably, exposed on the body in a direction substantially opposite to the direction towards which the cutting element <NUM> is exposed.

The body <NUM> comprises a plurality of positioning elements, three recesses <NUM> - substantially hemispherical in the example of the Figures -, each of which is suitable for receiving a complementary positioning element <NUM> of the tool holder <NUM> as appreciable in <FIG>. Preferably, the recesses <NUM> are arranged on the first lateral surface <NUM> so as to delimit a triangular region. In the example considered, the three recesses <NUM> are arranged at the vertices of said triangular region. Even more preferably, the recesses <NUM> are arranged at <NUM>° to each other with respect to the through-hole <NUM>.

In addition, although not necessarily, the body <NUM> comprised an inlet port <NUM> exposed on the first lateral surface <NUM>, which is configured to hydraulically match tightly with a corresponding outlet port <NUM> of the tool holder <NUM> - as visible in <FIG> - in order to receive the aforementioned lubrication/cleaning fluid.

In the embodiments of the present invention, the body <NUM> also comprises a second lateral surface <NUM>, which is configured to abut at least partially against a corresponding second lateral surface <NUM> of the tool holder <NUM> - as appreciable in <FIG>.

In the example considered, the second lateral surface <NUM> is adjacent to the first lateral surface <NUM> and comprises, as it moves away from the first lateral surface <NUM>, a connecting portion <NUM>, an inclined portion <NUM>, and an abutting portion <NUM>.

In detail, the connecting portion <NUM> follows one end of the first lateral surface <NUM> and the inclined portion <NUM> of the second lateral surface <NUM> and defines a circumferential arc profile with respect to a plane Π (illustrated in <FIG>) orthogonal to both the first lateral surface <NUM> and the second lateral surface <NUM>.

The inclined portion <NUM> is configured to define an angle α with the first lateral surface <NUM> with respect to the plane Π - as illustrated in <FIG> - that is less than an angle β defined between the first lateral surface <NUM> and the second lateral surface <NUM> of the tool holder <NUM>. In the example considered, the inclined portion <NUM> of the second lateral surface <NUM> and the first lateral surface <NUM> define an angle α that is acute, i.e., less than <NUM>° (α < <NUM>°), preferably between <NUM>° and <NUM>°, such as <NUM>°.

The abutting portion <NUM> is configured to abut against the second lateral surface <NUM> of the tool holder <NUM>, and, preferably, follows the inclined portion <NUM>. Even more preferably, the abutting portion <NUM> is substantially orthogonal to the first lateral surface <NUM> with respect to the plane Π.

Preferably, the second lateral surface <NUM> is conformed such that a free end thereof - distal from the first lateral surface <NUM> - included in the abutting portion <NUM> in the example considered is at a distance w from the first lateral surface <NUM> of between <NUM> and <NUM> times, preferably between <NUM> and <NUM> times a length l of the first lateral surface, both calculated in the plane Π.

The second lateral surface <NUM> delimits an elastic element <NUM> of the support body <NUM>. Advantageously, the elastic member <NUM> is configured to generate an elastic resisting force which has an orientation substantially orthogonal - and, preferably, substantially parallel to the plane Π - to said abutting portion <NUM> of the second support surface when the abutting portion <NUM> is abutting against the second lateral surface <NUM> of the tool holder <NUM>. In other words, the elastic element <NUM> is configured to elastically deform along a direction substantially parallel to the first lateral surface <NUM> when the tool body <NUM> of the tool <NUM> contacts and/or is constrained to the tool holder <NUM>.

In the embodiment considered, the elastic element <NUM> is a portion of the body <NUM> delimited by the second lateral surface <NUM>, a slot <NUM> extending into the body <NUM> and a free edge of the support body <NUM> between the first two.

Preferably, the slot <NUM> extends proximate to said free edge inwardly of the support body <NUM> and has an orientation parallel to or inclined with respect to the inclined portion <NUM> of the second lateral surface <NUM>. Further, the slot <NUM> extends transversely, preferably orthogonally, with respect to the plane Π. Advantageously, the orientation of the slot <NUM> with respect to the inclined portion <NUM> is selected to ensure that a thickness of the elastic element <NUM> - calculated with respect to the plane Π - is substantially constant or within an acceptable range of values throughout the extent of the slot <NUM> within the body <NUM>.

In the example considered, the slot <NUM> has a length along a direction parallel to or inclined with respect to the inclined portion of the second lateral surface between <NUM> and <NUM>, preferably between <NUM> and <NUM> times the length of the second lateral surface calculated in the plane Π. Further, the slot <NUM> has a distance from the second lateral surface between <NUM> and <NUM> times the length of the slot <NUM>, preferably between <NUM> and <NUM> times the length of the slot <NUM> calculated in the plane Π.

As mentioned above, the tool <NUM> couples to the tool holder <NUM> to form a cutting unit <NUM> according to one embodiment of the present invention. In detail, the tool holder <NUM> configured to couple to a machine tool (not shown) to the tool <NUM>.

The tool holder <NUM> comprises a machine connecting portion <NUM> configured to couple to the machine tool and a tool connecting portion <NUM> configured to couple to the tool <NUM>.

In the example considered, the machine connecting portion <NUM> comprises a plurality of through-holes <NUM> each adapted to receive a corresponding fastening screw <NUM> - as visible in <FIG> - and, optionally a hydraulic inlet port (not visible in the figures) to receive lubrication/cleaning fluid from the machine tool.

Otherwise, the tool connecting portion <NUM> comprises a first lateral surface <NUM> and a second lateral surface <NUM> adjacent to each other.

The tool holder <NUM> comprises a threaded hole <NUM> exposed on the first lateral surface <NUM> and configured to receive the screw <NUM> passing through the through-hole <NUM> of the tool <NUM> such that the tool <NUM> can be attached to the tool holder <NUM> by screwing said screw.

As mentioned above, the tool holder <NUM> comprises a plurality of complementary positioning elements, three hemispheres <NUM> in the example of the Figures, each of which is adapted to be received by a corresponding abutting element <NUM> of the tool <NUM> as appreciable in <FIG>. In other words, the hemispheres <NUM> are arranged to define a triangular region on the first lateral surface <NUM> of the tool holder <NUM> corresponding to the triangular region defined by the recesses <NUM> on the first abutting region <NUM> of the tool. In the example considered, the hemispheres <NUM> are arranged at <NUM>° to each other with respect to the threaded hole <NUM> in a manner corresponding to the arrangement of the abutting elements <NUM> - as best appreciated in the detail of <FIG>.

In addition, although not necessarily, the tool holder <NUM> comprises an outlet port <NUM> exposed on the first lateral surface <NUM>, which is configured to be sealingly coupled hydraulically with the corresponding tool inlet port <NUM> in order to transmit the aforementioned lubrication/cleaning fluid.

Advantageously, the tool holder <NUM> also comprises a sealing/ dampening element <NUM>, for example an O-ring, projecting from the first lateral surface <NUM>, preferably, so as to surround the threaded hole <NUM>.

In the example considered, the second lateral surface <NUM> of the tool holder is substantially a flat surface orthogonal to the first lateral surface <NUM> and preferably, orthogonal to the plane Π to which the first lateral surface <NUM> is also orthogonal.

In use, the tool holder <NUM> is mounted to the machine tool and then the tool <NUM> is attached to the tool holder <NUM> with the screws <NUM> being secured to the machine tool, which screws are passing through the holes <NUM>. In particular, the first lateral surface <NUM> of the tool <NUM> is juxtaposed to the first lateral surface <NUM> of the tool holder <NUM> so that the through-hole <NUM> and the threaded hole <NUM> are coaxial to each other and each of the recesses <NUM> receives a corresponding hemisphere <NUM> by mechanically coupling to the same.

In particular, the surfaces <NUM>' of the recesses <NUM> shown in <FIG> define an abutting surface of the first lateral surface <NUM> of the body <NUM>, which surface, when the tool <NUM> is coupled to the tool holder <NUM>, contacts a complementary abutting surface <NUM>' of the first lateral surface <NUM> of the tool holder <NUM>, which surface is defined by the surfaces <NUM>' of the hemispheres <NUM>.

Preferably, the first lateral surface <NUM> of the tool <NUM> remains spaced apart from the first lateral surface <NUM> of the tool holder <NUM> when the hemispheres <NUM> are coupled to the recesses <NUM> and the sealing/ dampening element <NUM> on the first lateral surface <NUM> of the tool holder <NUM> abuts against the first lateral surface <NUM> of the body <NUM>.

At same time, the second lateral surface <NUM> of the tool <NUM> couples to the second lateral surface <NUM> of the tool holder <NUM>, in particular, the abutting portion <NUM> of the second lateral surface <NUM> of the tool <NUM> abuts against the second lateral surface <NUM> of the tool holder <NUM>.

The screw <NUM> is then threaded through the through-hole <NUM> of the tool <NUM> and through the threaded hole <NUM>, thereby securing the tool <NUM> to the tool holder <NUM>. In other words, the through-hole <NUM>, the threaded hole <NUM>, and the screw <NUM> are fastening elements that form a fastening unit for securing the tool <NUM> to the tool holder <NUM>.

Eventually, the elastic element <NUM> deforms - at the limit to the point of contact of the body walls <NUM> delimiting the slot <NUM> - thereby compensating for manufacturing tolerances of the tool <NUM> and/or the tool holder <NUM>.

The embodiments of the invention described above are susceptible to numerous modifications and variations all within the scope of the present invention.

For example, in embodiments (not illustrated) of the present invention, the connecting portion of the second side surface of the tool is omitted. In this case, the inclined portion of the second lateral surface is adjacent to the first side surface of the tool.

Additionally, or alternatively, in alternative embodiments (not shown) of the present invention, the abutting portion has a minimum size, in particular, the abutting portion may correspond to a substantially linear portion - for example, an edge of the body. In this case, the direction of the elastic force is to be considered orthogonal to the abutting portion when orthogonal or inclined to the second lateral surface of the tool holder.

In any case, the abutting portion may be provided with a sealing/dampening element (not shown) - such as an O-ring - so as to ensure greater stability of the coupling between the secondary surfaces of the tool and the tool holder.

Again, nothing prevents providing an embodiment (not illustrated) in which the first lateral surface of the tool body and the first lateral surface of the tool holder are configured to contact each other once the tool is secured to the tool holder.

In other embodiments (not illustrated), the connecting portion has a concave shape other than a circumferential arc - for example, a sequence of broken lines - preferably, suitable for receiving an edge defined by the first lateral surface and the second lateral surface of the tool holder.

In a different embodiment (not illustrated), the elastic element is a protruding appendage of the support body. In this case, the appendage protrudes from the body in a direction orthogonal or inclined to the first support surface, preferably, such that a free end of the appendage - distal from the first lateral surface of the body - is at a distance from the first lateral surface of between <NUM> and <NUM> times, preferably between <NUM> and <NUM> times, a length of the first lateral surface, where both the distance and the length are calculated in a plane orthogonal to both abutting surfaces.

Even more preferably, the appendage has a width of between <NUM> and <NUM> times, preferably between <NUM> and <NUM> times a distance between the free end of the appendage and the first lateral surface of the body calculated in a plane orthogonal to both abutting surfaces.

In an alternative embodiment (not illustrated), the tool and the tool holder are devoid of any abutting elements - such as the recesses and hemispheres considered above - in which case the tool abutting surface corresponds substantially to the first lateral surface of the tool body and, similarly, the complementary abutting surface corresponds to the first major surface of the tool holder.

It is to be understood that all details can be replaced by other technically equivalent elements.

For example, the screws may be replaced by other fastening elements of the known type, wherein there may be provided complementary fastening units formed and/or coupable to the first lateral surface of the tool and the first lateral surface of the tool holder, for example fastening units comprising one or more snap-on or bayonet fastening elements.

Claim 1:
Cutting tool (<NUM>) comprising:
- a cutting element (<NUM>) configured to come into contact with a body to be machined, and
- a support body (<NUM>) configured to support the cutting element (<NUM>) in a working position and to be coupled to a tool holder (<NUM>) mounted on a processing machine, wherein the support body (<NUM>) comprises a first lateral surface (<NUM>) configured to be brought alongside to a first surface (<NUM>) of the tool holder (<NUM>), the first lateral surface (<NUM>) comprising:
- a matching surface (<NUM>') configured to match a complementary matching surface (<NUM>) of the first surface (<NUM>) of the tool holder (<NUM>), and
- at least one fastening element (<NUM>) configured to match a corresponding fastening element (<NUM>) comprised in the first surface (<NUM>) of the tool holder (<NUM>) for fastening the tool to the tool holder (<NUM>),
wherein the support body (<NUM>) comprises a second lateral surface (<NUM>) configured to abut at least partially against a second surface (<NUM>) of the tool holder (<NUM>), said second lateral surface (<NUM>) being adjacent to the first lateral surface (<NUM>), and comprising at least an inclined portion (<NUM>) with respect thereto and an abutment portion (<NUM>) configured to abut against the second surface (<NUM>) of the tool holder (<NUM>),
characterized in that the second lateral surface (<NUM>) delimits an elastic element (<NUM>) of the support body (<NUM>), said elastic element (<NUM>) being configured to generate a resistant elastic force substantially orthogonal to said abutment portion (<NUM>), when the abutment portion (<NUM>) is in contact with the second surface (<NUM>) of the tool holder (<NUM>).