Interface between a collet holder and a tool adapter

The invention relates to an interface between a collet holder and a tool adapter, said interface being simple in construction and in which the insertion of a tool adapter is possible in a simple manner even in confined spaces.

With the help of collets, rotating tools can be tensioned very precisely and compactly. However, since not all tools can be tensioned in a collet, there is a need to provide a collet holder in which both collets and tool adapters for driven or stationary tools can be accommodated.

From DE 102 19 600 C5, a tool carrier with a collet holder is known, in which tool adapters can be used as an alternative to the collets. The tool adapters have a flange plate. The tool adapter is attached via said flange plate to the collet holder by means of four screws arranged on the front side of this flange plate.

From DE 10 2009 060 678 B4 of the applicant, a tool carrier with a collet holder and a tool insert for use in such a tool carrier are known. The tool carrier has an outer thread onto which a tensioning nut with an inner thread is screwed in order to secure both collets and tool adapters in the tool carrier.

A similar solution is known from DE 20 2009 012 087 U1. Here too, both the collets and the tool adapters are secured in the collet holder using a tensioning nut.

A tool tensioning device is known from DE 10 2004 029 047 A1. In this interface, an annular shoulder and a circumferential groove are formed in a tool adapter in the axial direction in front of an outer cone. A tensioning pin of the associated spindle can be screwed into the circumferential groove and in this way the tool adapter can be axially tensioned with the spindle. This solution requires additional installation space or shortens an outer cone of the tool adapter. This has a negative impact on the concentricity of a tool tensioned in the tool adapter.

An interface between a tool carrier and a tool adapter is known from DE 10 2009 042 665 A1. No collets can be inserted into this interface. In this interface, a form-locking connection is first established in the manner of a bayonet connection between the tool adapter and tool mount.

Then the connection is fixed by a targeted elastic deformation. This interface requires very small manufacturing tolerances and is therefore sensitive to wear and soiling. It is also expensive to manufacture.

These solutions known from the prior art have proven themselves in many applications; however, they have disadvantages, which are particularly important when there is little space in the work space of the machine tool for changing a tool adapter.

In the solution known from DE 102 19 600 C5, four screws have to be inserted from the end face through the flange plate and screwed into the collet holder. This means that access from the front of the collet holder is required if a tool adapter is to be used. In addition, four screws must be screwed in, in order to secure a tool adapter.

From DE 299 13 650 U1, an interface between a tool adapter and a spindle insert is known. The spindle insert has two slanting tensioning screws. The tool adapter has two longitudinal grooves and a circumferential groove with a slanted groove edge. The interaction of the tensioning screws results in a bayonet-like quick release.

From the U.S. Pat. No. 3,762,731, a collet holder is known in which a tool adapter can be pressed into the collet holder by means of the tensioning nut of the collet. In the tool adapter, a radially aligned recess is provided, which picks up a clamping bolt. The collet holder has a radially aligned internal thread with a tensioning pin. By turning the tensioning pin, the tensioning bolt is pressed against the shank of a tool enclosed in the tool adapter and the tool is held in the tool adapter. U.S. Pat. No. 4,437,801 describes a very similar system. The main difference is that the tensioning pin presses directly onto the shank of a tool enclosed in the tool adapter.

In the solutions known from the prior art with a tensioning nut, the collet holder must be secured against rotation and a key for loosening or tightening the tensioning nut must be used in order to change a collet or a tool adapter. In situations with limited space, as is often the case with Swiss-type automatic lathes, there is not enough space for this.

The invention has for its object to provide a collet holder and an associated tool adapter, which allow a tool adapter to be inserted and fixed securely and with high repeatability into a collet holder in a simple manner, even in confined spaces.

This object is achieved in an interface between a collet holder and a tool adapter, the collet holder comprising an inner cone, a flat surface, and an outer thread for a tensioning nut, wherein the tool adapter comprises an outer cone which complements the inner cone, and the collet holder has securing means, which are independent of the outer thread and the tensioning nut, for the tool adapter, in that according to the invention the independent securing means comprise one or more radially or diagonally arranged inner threads and a tensioning pin in each inner thread, and that one or more recesses which interact with the tensioning pin(s) are provided in the tool adapter.

In the solution according to the invention, the tool adapter is not secured in the collet holder by means of the outer thread of the collet holder and a tensioning nut, but rather by means of independent securing means in the form of radially or diagonally arranged tensioning pins. The tensioning pins are screwed with their tips into complementary recesses in the tool adapter.

To tension the tool adapter in the collet holder according to the invention, only a lateral or radial accessibility for a screwdriver is required. A torque support in the form of a second tool for counter-holding is not necessary in the interface according to the invention. This considerably simplifies the changing and tightening of a tool adapter according to the invention. It is also sufficient to loosen or tighten a single tensioning pin. This also saves a lot of time when changing the tool adapter compared to other known solutions.

A screwdriver is a very slim and inexpensive tool, which allows the tool adapter to be tensioned or loosened in a simple manner, even when space is limited in the machine's work area.

Because the recesses are frustoconical, but in any case are rotationally symmetrical with respect to a central axis, tensioning forces in the axial direction and torques can be transmitted via the tensioning pin and the recess. In addition, the recess can be made in the outer cone of the tool adapter; it therefore does not require any additional installation space.

The interface according to the invention is used especially when tools with small diameters and correspondingly high speeds are used. This means that the torques to be transmitted between the collet holder and tool adapter are comparatively low. Therefore, in many cases it is sufficient if the torque transmission between the collet holder and the tool adapter takes place via the tensioning pin(s).

A particularly advantageous embodiment of the invention provides that the collet holder has one or more (radial) grooves or depressions in the area of the flat surface, that the tool adapter also has one or more (radial) grooves or depressions in the area of the collar, and that a separate driver ring belongs to the interface, which has at least one form-locking element that can be inserted into the grooves or depressions in the area of the flat surface and in the area of the collar. In other words: Both the collar and the flat surfaces only have grooves or depressions. As a result, the collar and the flat surface are very simple to manufacture and can be manufactured with high precision and axial run-out.

The form-locking elements provided for precise or unambiguous positioning (and optionally also for positive torque transmission) are integrated in a driver ring designed as a separate component. If required, i.e. if a tool adapter is inserted into the collet holder, this driver ring is pushed over the outer thread of the collet holder and the tensioning pins that were previously screwed in, until the form-locking elements of the driver ring engage in the grooves of the collet holder. The tensioning pins are then positioned such that the tool adapter can be inserted into the collet holder in such a way that the grooves on the collar of the tool adapter accommodate the form-locking elements of the driver ring. This ensures precise positioning between the collet holder and the tool adapter. The tool adapter is then fixed with the help of one or more tensioning pins in the manner described above. In addition, this form-locking connection can also be used for torque transmission between the tool holder and tool adapter.

Additionally or alternatively, it is also possible that a positive torque transmission between the tool adapter and collet holder in the area of the flat surface and a collar of the tool adapter or in an area at the rear end of the inner cone of the collet holder (see claim13) or at another location between the front and rear end is done.

The optional collar of the tool adapter does not have to be in contact with the flat surface of the collet holder. The tool adapter is then positioned and centered exclusively via the inner cone of the collet holder and the outer cone of the tool adapter.

If the collar of the tool adapter is pulled against the flat surface of the collet holder, the axial runout of the tool adapter is improved even further.

To ensure that the tool adapter can only be inserted into the collet holder in such a way that the recesses on the tool adapter interact with the tensioning pins of the collet holder, it is possible and in many cases also advantageous if, for example, the width of the grooves on the flat surface is not the same. The same applies correspondingly to the width of the grooves on the collar of the tool adapter and to the width of the form-locking elements of the driver ring according to the invention. As a result, the position in which the tool adapter can be inserted into the collet holder is structurally predetermined. As an alternative to the width of the grooves, the position in which the tool adapter must be inserted into the collet holder can also be specified by means of the groove depth and the associated dimension of the form-locking element(s) on the driver ring or via the (uneven) arrangement of the grooves and form-locking elements over the circumference of the flat surface and the collar.

The structurally predetermined positioning of the tool mount and tool adapter relative to one another ensures that the tips of the tensioning pins engage in the complementarily arranged recesses in the tool adapter when the tensioning pin(s) are tightened. Incorrect assembly is therefore impossible.

This unequal dimensioning and/or arrangement of the grooves does not cause any significant imbalance if the collet holder, the tool adapter and the driver ring are made of the same material, e.g. made of steel. As already mentioned, the tensioning is done by tightening the tensioning pin(s).

In addition, the form-locking elements can be arranged on the ring in such a way that they have a certain elasticity in the axial direction and serve as ejectors for the tool adapter.

When tensioning the tool adapter, it is pulled with its collar against the flat force of the collet holder against the spring force exerted by the form-locking elements by tightening the tensioning pin(s).

If the tool adapter is to be removed from the collet holder at a later time and the tensioning pin(s) are loosened for this purpose, the axially preloaded form-locking elements actively support the ejection of the tool adapter.

This further improves the handling of the interface according to the invention. This is particularly helpful if the inner cone and the outer cone have a slightly self-locking effect or if the inner cone and the outer cone are glued to one another by adhering cooling lubricant.

The driver ring also covers the outer thread of the collet holder and protects it from damage or dirt if no tensioning nut is screwed onto the outer thread.

In a further advantageous embodiment of the invention, the driver ring has at least one radial or diagonal through bore through which a screwdriver can be inserted in order to tighten or loosen a tensioning pin according to the invention.

The diameter of the at least one through bore in the driver ring can be so large that

a) the tensioning pin and the screwdriver fit or

b) only the screwdriver fits.

In case a), the tensioning pin can be screwed into the tool adapter and removed therefrom.

In case b), the tensioning pin cannot be removed as long as the driver ring is in place. Then the tensioning pin secures the driver ring against falling down and getting lost.

Because there is a clear spatial assignment between the grooves in the flat surface of the collet holder and the inner thread for the tensioning pins in the collet holder, it is also possible to easily design the driver ring such that the at least one through bore is positioned in the driver ring, in such way that the screwdriver, when inserted through the through bore of the driver ring, reaches the head of the tensioning pin. If there are several tensioning pins on the collet holder, the driver ring will of course have several through openings.

If, in a further embodiment according to the invention, the minimum diameter of the through bore is just large enough that a screwdriver for tightening and loosening the at least one tensioning pin can be inserted into the through bore, the driver ring also serves as a captive device for the tensioning pins. If the tensioning pin is unscrewed too far, it will hit the driver ring and cannot be unscrewed any further.

It is also advantageous if the through bore is designed as a stepped bore and the stepped bore on the inside of the driver ring has a larger diameter than on the outside of the driver ring and if the diameter of the stepped bore on the inside of the driver ring is slightly larger than the nominal diameter of the tensioning pin(s). Then the tensioning pin can be turned a bit into the stepped bore. Only when the diameter of the stepped bore is reduced, the tensioning pin hits the driver ring and cannot be unscrewed any further. In this position, the tensioning pin also serves as a captive device for the driver ring, such that a tool adapter can be replaced without the risk of the driver ring falling down from the collet holder and into the working area of the machine tool.

In addition, the driver ring according to the invention has other optional functions.

Ejecting the tool adapter can also be actively supported by loosening/unscrewing the tensioning pins. This can be achieved by a suitable design of the through bore(s) in the driver ring and/or a suitable positioning of the through bore(s) in the driver ring relative to the inner thread(s) in the collet holder. The result of both alternatives is that, by loosening the tensioning pin(s), an axial force is indirectly exerted by the tensioning pin(s) on the driver ring on the tool adapter, said axial force supporting the ejection.

If, for example, the through bore or a chamfer or rounding of the through bore in the driver ring is arranged offset in the axial direction to the tensioning pin, then the tensioning pin hits axially offset against an edge or a chamfer at the transition from the inner larger diameter to the smaller diameter of the through bore. This offset pressing of the tensioning pins causes the tool adapter to be ejected, or at serves as an aide therefor.

Alternatively, the inner section of the through bore can be formed with a larger diameter than the cone, which is slightly offset in the axial direction from the longitudinal axis of the inner thread.

Alternative configurations of form-locking connections provide that the collet holder has one or more projections in the area of the flat surface and the tool adapter in the area of the collar has one or more recesses or depressions complementary to the projections.

Alternatively, it is also possible for the tool adapter to have one or more projections in the region of the collar and for the collet holder to have recesses or depressions which are complementary to the projections in the region of the flat surface. These projections can also be inserted sliding blocks or inserted pins. In these alternatives, an driver ring is not necessary.

Alternative or additional configurations provide that the tool adapter and the collet holder can be connected in a form-locking manner to one another at an end of the inner cone opposite the flat surface. Such a form-locking connection can be, for example, a polygon connection between the tool adapter and the collet holder.

As an alternative or in addition, it is also possible for a plurality of axial grooves to be formed in the collet holder or in the tool adapter and for these axial grooves to interact with projections on the tool adapter or the collet holder in the sense of a positive torque transmission.

Another alternative provides for the torque to be transmitted by means of a claw coupling between the collet holder and the tool adapter.

The functions “positioning of tool mount and tool adapter” and “torque transmission from the tool mount to the tool adapter” can be realized by the form-locking connection in the area of the flat surface and the collar or by the form-locking connection at the opposite end of the tool mount.

However, it is also possible that the “positioning tool mount and tool adapter” function is realized by the form-locking connection in the area of the flat surface and the collar, and the “torque transmission from the tool mount to the tool adapter” function is implemented at the opposite end of the tool holder. The reverse assignment of functions is also possible.

This “division of tasks” is realized constructively by means of the rotational free play and the arrangement in the axial direction of both form-locking connections. The form-locking connection with the larger rotational free play is positioned in the axial direction such that it becomes active when the tool adapter is inserted and takes over the positioning; the other form-locking connection takes over the “torque transmission” function.

It has also been found to be particularly advantageous if a nominal diameter of the outer thread for the tensioning nut is at least 1.4 times larger, preferably 1.5 times to 1.8 times larger, than the largest diameter Dmaxof the inner cone.

With increasing wall thickness of the collet holder between the inner cone and the outer thread, the inner thread becomes longer, such that the resilience thereof increases. In addition, the tensioning pin(s) can have a longer design, which means that the tensioning pins can better absorb the lateral forces that occur when the tool adapter is tensioned. This also results in a very strong and stable collet holder.

The interface according to the invention can be integrated in a driven tool mount, in particular a driven tool mount for Swiss-type automatic lathes, or a stationary tool mount.

In a further development of the interface according to the invention, there are several grooves on the outer cone of the tool adapter. The grooves preferably run in the circumferential direction. These grooves can generally run anywhere on the outer cone; for example in the axial direction. However, circular or spiral designs are preferred for manufacturing reasons. These grooves provide a small storage volume when inserting and tensioning the tool adapter into the spindle, which hold the cooling lubricant present in the area of the inner cone of the spindle and the outer cone of the tool adapter. Assuming the same tensioning force, this significantly reduces the thickness of the film of cooling lubricant on the contact surface between the inner cone of the spindle and the outer cone. As a result, the concentricity of the tool adapter is further improved.

When arranging the grooves, it is important to make sure that they stop in good time at least before one of the two cone ends in order to create a sufficient sealing area without interruption. This sealing area is necessary such that cooling lubricant cannot accidentally escape from the interior of the tool holder through the spiral groove.

In a further advantageous embodiment of the invention, the tensioning pin(s) have a frustoconical tip. Additionally or alternatively, it is also possible for the tensioning pin(s) to have a tip arranged eccentrically to an outer thread of the tensioning pin. This tip can be frustoconical or cylindrical. Then the tensioning pin works as an eccentric tensioning pin.

Further advantages and advantageous embodiments of the invention can be found in the following drawings, the description thereof and the claims. All of the features described in the drawing, the description thereof and the claims can be essential to the invention both individually and in any combination with one another.

DESCRIPTION OF THE EMBODIMENTS

FIGS. 1a, 1b,2and3show an embodiment of a collet holder300according to the invention, which is integrated in a spindle100. The spindle100can, for example, be integrated in a driven tool mount according toFIGS. 10, 11, and 12. With driven tool mounts, the spindle is rotatably mounted in the tool mount and rotates during machining.

Alternatively, it is also possible for the spindle to be integrated in a fixed tool mount or to be designed as a fixed tool mount, as is illustrated with reference toFIGS. 17 and 18and will be explained in more detail below.

The actual collet holder300is located inFIGS. 1aand 1bat the left end of the spindle100. The collet holder300according to the invention comprises an inner cone310, a flat surface311and an outer thread230. The inner cone310can correspond to DIN ISO 15488, such that standardized collets400can be used in the collet holder300according to the invention.

A tensioning nut401is screwed onto the outer thread230of the spindle100in a manner known per se (seeFIG. 1b). When the tensioning nut401is tightened, it presses a collet400(seeFIG. 1b) into the inner cone310. As a result, a tool with its cylindrical shank (not shown inFIGS. 1 to 3) is tensioned in the collet400.

The inner cone310has a front end312and a rear end313. InFIGS. 1aand 1b, the front end312is arranged on the left. At the front end312, the inner cone310has its largest diameter Dmax.

At the rear end313, the inner cone has its smallest diameter Dmin. In this exemplary embodiment, the inner cone310merges into a cylindrical bore314at313. The optional cylindrical bore314makes it possible to push the shank of a tool tensioned in the collet400(not shown) through the collet400in the direction of the cylindrical bore314. As a result, the axial distance between the cutting edge(s) of the tool and the flat surface311can be set. The aim is to keep this distance as small as possible in order to achieve the most rigid possible tensioning of the tool. This improves the machining accuracy, the possible cutting performance and the service life of the tool. In the configuration shown inFIGS. 1 to 3, the axial distance between the cutting edge(s) of the tool and the flat surface311can only be set in the working space of the machine tool. This is undesirable because it leads to relatively long unproductive downtimes of the machine tool and the repeatability of the setting is low.

The outer thread230has a nominal diameter Dnennwhich is significantly larger than the diameter Dmaxat the front end312of the inner cone310. In practice, it has proved advantageous if the nominal diameter Dnominalof the outer thread230is at least greater by a factor of 1.4 than the maximum diameter Dmaxof the inner cone310. Then the wall thickness between the outer thread230and the inner cone310is sufficient to provide a radially or diagonally running inner thread315into which a screw plug402or a tensioning pin210can be screwed. The inner thread has a frustoconical countersink (without reference numeral) at its radial outer end.

As an alternative to the radial course shown, the inner thread315can also run obliquely (not shown), such that the longitudinal axes of the inner cone310and the inner thread315enclose an angle α greater than 90°, preferably 105° or 120°.

A locking screw402is screwed into the inner thread315when a collet400and a tensioning nut401are used for tensioning a tool.

The locking screw402has a frustoconical upper end which, together with the conical countersinking of the inner thread315, seals the inner thread315. This prevents cooling lubricant, which is supplied to a tool tensioned in the collet400, from getting into the environment in an uncontrolled manner through the inner thread315. In addition, the inner thread315is protected against damage or contamination by the screw plug402.

InFIGS. 2 and 3, the spindle is shown in different views. The screw plug402can be clearly seen inFIG. 2. The outer thread230is not illustrated inFIG. 2. Instead, only a cylindrical surface is provided with the reference symbol230. The collet holder300according to the invention of the spindle100works in the configuration shown inFIGS. 1bto3, like a conventional collet holder according to DIN ISO 15488 with a tensioning nut.

A second configuration is shown in different views inFIGS. 4 to 9. In this configuration, instead of a collet400and a tensioning nut401, a tool adapter500according to the invention is inserted into the inner cone310of the collet holder300.

FIG. 9shows this configuration in an exploded view. A tensioning pin210is inserted into the inner thread315of the collet holder300. In the illustrated embodiment, the inner thread315is arranged radially. This means that the longitudinal axis of the inner thread315runs radially and orthogonally to the longitudinal axis of the spindle100. It is also possible that an angle α between the longitudinal axis of the inner thread315and the longitudinal axis of the spindle100is different from 90°. For example, the angle could not be 90°, as shown inFIG. 9, but rather 105° or 120°.

The tensioning pin210has a truncated cone316at one end in this exemplary embodiment. A driver for a screwdriver is formed at the opposite end of the tensioning pin210. At the left end of the spindle100inFIG. 9, the flat surface311is clearly visible. The flat surface311interacts with a collar321of a tool adapter500.

Grooves221and223are formed both in the flat surface311and in the collar321, which can also be referred to as recesses. In this exemplary embodiment, the grooves221and223run radially and are arranged such that the grooves221and223are opposite one another when the tool adapter500is inserted into the spindle100.

Because there are no projections on both the flat surface311and the collar321, the collar321and the flat surface311can be produced very simply and precisely. For example, both surfaces can be produced by grinding in order to be exactly flat and at right angles to the longitudinal axis of the spindle100or the tool adapter500. It is also possible to provide the flat surface311and/or the contact surface of the collar321interacting therewith with a hollow grinding. As a result, the contact area between collar321and flat surface311is reduced to an annular area and there is a certain elasticity between the spindle100and the tool adapter500in the axial direction, such that the tool adapter500is drawn into the inner cone310in the axial direction by tightening the tensioning pin210against the preload resulting from the slight elastic deformation.

If the tensioning pin210is released to release the connection between the tool adapter and the collet holder300, the tool adapter500springs back again and the connection is released. This axial deformation is usually less than 0.03 mm.

An driver ring220according to the invention is provided between the spindle100and the adapter500. The driver ring220comprises two form-locking elements222, which are compatible with the grooves221in the flat surface311and the grooves223in the collar321. Compatible in this context means that the form-locking elements222immerse both in the grooves221and in the grooves223when the driver ring220is placed on the spindle100and the tool adapter500is inserted into the tool holder or the spindle100.

The driver ring220comprises a tubular section224, which connects the form-locking elements222to one another and also serves as a cover for the outer thread230. A through bore225is formed in the tubular portion224. The through bore225is positioned such that it lies over the inner thread315or the tensioning pin210when the form-locking elements222of the driver ring220are inserted into the grooves221of the spindle100or the collet holder300. If the spindle100only has an inner thread315and only one tensioning pin210, then it is particularly advantageous if the grooves221.1and221.2differ, for example, in width or depth. In a corresponding manner, the form-locking elements222.1and222.2are then of different widths or depths (see alsoFIG. 23and the description thereof). This ensures that the driver ring220can only be installed in one position, and in such a way that the through bore225is located above the inner thread315or the tensioning pin210.

The same applies to the form-locking elements222.1and222.2and the grooves223.1,223.2in the collar321. Only one groove223.1is visible inFIG. 9. The groove223.2arranged opposite is covered by the collar321.

FIGS. 4 and 5show the exemplary embodiment as shown inFIG. 9in the assembled state. It is clear fromFIG. 4that the driver ring220covers the outer thread230of the spindle100or the collet holder300. The through bore225releases the tensioning pin210to such an extent that a screwdriver (not shown) can be inserted into the driver element of the tensioning pin210and the tensioning pin210can be rotated.

FIG. 5shows a side view of the configuration according toFIG. 4.

FIG. 6shows a section along the line G-G through the spindle100, the tool adapter500according to the invention, and the driver ring220. In this illustration, the form-locking between the spindle100and the tool adapter500can be clearly seen with the aid of the form-locking elements222.

In this exemplary embodiment, the tool adapter500carries a small collet holder with an outer thread and a tensioning nut. This makes it possible to tension tools with small shank diameters in a collet. In addition, the axial distance between a cutting edge of the tensioned tool and the flat surface311of the collet holder300outside the machine tool can be set exactly.

FIG. 7shows the situation in which the tensioning pin210is screwed into a recess317in the outer cone320of the tool adapter500.

The recess317is frustoconical, as can be seen fromFIGS. 7 and 8. The cone angle of the recess317and the cone angle of the truncated cone316on the tensioning pin210are the same. As can be seen fromFIG. 7andFIG. 8, a central axis of the tensioning pin210or the inner thread225is somewhat offset from a central axis of the recess317(see the dash-dotted center lines of the tensioning pin210and the recesses317that are somewhat offset in the axial direction). The offset is selected such that the outer cone320of the tool adapter500is pulled into the inner cone310by screwing the tensioning pin210into the recess317. As a result, the collar321of the tool adapter500is pulled against the flat surface311. As a result, the tool adapter500is aligned with very small tolerances and great repeatability in the spindle100or the inner cone310and the flat surface311. In other words: Concentricity and runout of a tool tensioned in the tool adapter500are very good.

However, designs are also possible in which the collar321of the tool adapter500has no contact with the flat surface311of the spindle100. Then the tool adapters are positioned and centered over the cones.

Because the recesses317are frustoconical, but in any case are rotationally symmetrical with respect to a central axis, not only tensioning forces in the axial direction (i.e. in the direction of an axis of rotation of the spindle10) can be transmitted by means of the tensioning pin210and the recess317, but also torques, i.e. forces are transmitted in the circumferential direction. In addition, the recess317can be made in the outer cone320of the tool adapter; it therefore does not require any additional installation space.

FIG. 8shows the situation that the tensioning pin210is unscrewed from the recess317, such that the tool adapter500can be removed from the inner cone310.

It can also be clearly seen inFIG. 8that the driver ring220serves as a captive device for the roll pin210. Because the tensioning pin210abuts the driver ring220, the tensioning pin210cannot be completely unscrewed from the inner thread.

If the bore225in the driver ring220is designed as a stepped bore, as illustrated inFIG. 8, the tensioning pin210cannot be completely unscrewed and at the same time the driver ring220can no longer be removed from the spindle100or tool holder300, since the driver ring is prevented therefrom by the tensioning pin210. Then the tensioning pin210serves as a captive device for the driver ring.

The tensioning pin210can in any case be turned so far that the truncated cone316no longer dips into the recess317of the tool adapter500.

The interface according to the invention offers considerable advantages when it comes to accommodating tool adapters500to504in a collet holder300in a form-locking manner with high repeatability and very low radial runout deviations and axial runout deviations.

In addition, the tool adapter according to the invention can be used and replaced easily and quickly even in confined spaces.

It is possible to design the interface according to the invention without the driver ring and without the grooves221and223in the flat surface311or the collar321. The positive torque transmission then takes place by means of the at least one tensioning pin210.

Alternatively, it is also possible to implement the positive torque transmission between the tool adapter500and spindle100at the rear end313of the inner cone310or the collet holder300. For this purpose, exemplary embodiments are described further below in connection withFIGS. 19, 20, and 21.

FIG. 10shows an application example of an interface according to the invention. It is a driven angled tool mount600with three spindles. Such tool mounts600are used, for example, in Swiss-type automatic lathes. Workpieces with a relatively small turning diameter are machined there. There is little space in the work area to change a tool adapter or a tool tensioned in a collet.

A collet400having a tensioning nut401corresponding to the exemplary embodiment inFIGS. 1 to 3is inserted into the first spindle. It is easy to imagine that the insertion of a tool and the precise setting of the axial distance between the cutting edges of the tool and the collet holder300is difficult and time-consuming in these confined spaces.

Tool adapters500according toFIGS. 4 to 9are inserted into the other two spindles. The driver rings220with the through bores225and the tensioning pins210lying behind are clearly visible.

FIG. 10also clearly shows that the attachment elements of the tensioning pins210are easily accessible with a screwdriver through the through bore225of the driver ring220.

Because the tensioning pins210can be easily reached from the side with a screwdriver, the tool adapters500according to the invention can easily be exchanged even in these confined installation conditions. A second tool and a second hand of the machine operator to hold it up are not required.

FIGS. 11 and 12show a second exemplary embodiment of a tool mount600according to the invention. In this embodiment there is only one spindle. InFIG. 11, a tool adapter500having a driver ring220is arranged on the spindle.

InFIG. 12, a collet with a tensioning nut401corresponding toFIGS. 1 to 3is used in the same tool mount.

Various exemplary embodiments of tool adapters500to504are shown as examples inFIGS. 13 to 16.FIG. 13shows the tool adapter having the collet according toFIGS. 4 to 9again.

In the exemplary embodiment according toFIG. 14, a cutting tool (shown here as a drill) and a tool adapter502are formed in one piece. This can be done, for example, by soldering a hard metal drill into the actual tool adapter502.

FIG. 15shows a tool adapter503which has the function of a sealing plug. This tool adapter503is always used when a spindle is not required in order to prevent the inner cone311of this spindle from becoming dirty and/or the cooling lubricant escaping in an uncontrolled manner through said inner cone into the machine room.

FIG. 16shows a tool adapter504in which the tool adapter carries a turning tool. This turning tool can be enclosed in a fixed tool mount700(seeFIGS. 17 and 18). The turning tool can also be inserted into a driven tool mount. Then it has the function of a cutter with which internal bores can be drilled out.

A non-driven tool mount700is shown schematically inFIG. 17. The non-driven tool mount700here has a square shank and an interface according to the invention at one end. For example, a tool adapter501can be inserted into this interface according to the invention. The tool adapter501can be connected to the tool mount700with the aid of the tensioning pin210. Then this fixed tool adapter700can be used as a turning tool. Depending on the requirements, other tool adapters such as, for example,504(seeFIG. 16) can be used.

FIG. 18shows two fixed tool mounts700(here with cylindrical shank and tensioning surface) arranged side by side. The aforementioned turning tool504is tensioned in a tool mount700. A drill505is tensioned in the other tool mount with the aid of a tool adapter500having a collet.

The tool mounts700are in turn tensioned in a guide, which are part of the Swiss-type automatic lathe or another machine tool.

FIGS. 19 and 20show two examples of how the positive torque transmission at the rear end of the inner cone310or at the rear end of the outer cone320of a tool adapter500according to the invention can be realized.

In the exemplary embodiment shown inFIG. 19, a polygon322is formed at the rear end of the outer cone320. A complementary polygon is formed in the associated collet holder300(not shown). As a result, a torque can be transmitted from the collet holder300to a tool adapter500-504.

In the exemplary embodiment shown inFIGS. 20 and 21, a plurality of radial projections323distributed over the circumference are formed at the rear end of the outer cone320. The complementary axial grooves325are visible in the associated collet holder300(seeFIG. 21). Torque can be transmitted from the collet holder300to a tool adapter500-504by means of the projections323and the axial grooves325.

FIG. 22shows a longitudinal section of a tool adapter500according to the invention with collet holder340for tensioning a tool505(here a twist drill) and a spindle100with a collet holder300according to the invention. It is clear from this illustration that the axial position of the tool505can be adjusted relative to the tool adapter500by the tool505with its cylindrical shaft being pushed more or less far into the collet holder. This adjustment process takes place outside the machine tool with great accuracy and without the machine tool being at a standstill.

If such a tool adapter500according to the invention with a preset tool is to be inserted into the collet holder300of a tool mount, which is located in the working space of a machine tool, this only requires loosening a tensioning pin210, inserting the preset tool adapter500and tightening the tensioning pin210. This is very quick and can also be carried out without errors by machine operators with little qualifications.

FIG. 23shows how it can be ensured in a simple manner that the tool adapter500-504can only be inserted into the collet holder300in such a way that the recesses on the tool adapter500-504interact with the tensioning pins210of the collet holder300. As can be seen from the views inFIG. 23, the widths X, Y of the grooves221.1and221.2in the collet holder300can be different. The same applies correspondingly to the width of the grooves223.1and223.2on the collar321of the tool adapter500(not shown inFIG. 23) and to the width of the form-locking elements222.1and222.2of the driver ring220according to the invention (not shown inFIG. 23).

The same effect can be achieved if the depths V, W of the grooves221.1and221.2are different. The same applies correspondingly to the depth of the grooves223.1and223.2on the collar321of the tool adapter500(not shown inFIG. 23) and to the height of the form-locking elements222.1and222.2of the driver ring220according to the invention (not shown inFIG. 23). As a result, the position in which the tool adapter can be inserted into the collet holder is structurally predetermined.

The interface according to the invention is very easy to control in terms of production technology. Another advantage of the interface according to the invention can be seen in the fact that it is possible to use the interface in a first step like a normal collet. Then is closed in the inner thread315with a screw402.

If at a later time the need arises to equip the interface according to the invention with tool adapters500,501,502,503or504, then the necessary tool adapters500,501,502,503or504can be obtained and used at this time. The interface according to the invention thus offers minimal investment costs if initially only collets are to be used. At the same time, the “upward compatibility” of the solution according to the invention ensures that tool adapters according to the invention can be procured and used at a later point in time and without having to convert the driven tool mount. No interface known from the prior art offers these advantages.

FIGS. 24 and 25show an embodiment of the driver ring220in which the tensioning pin210also serves to press off the tool adapter500-504. This is achieved in that a chamfered or frustoconical countersink318is provided on the inside of the through bore225of the driver ring220.

A center of this countersink318is preferably arranged somewhat offset to the longitudinal axis of the inner thread315or the tensioning pin210. InFIGS. 24 and 25, the center of the countersink318is offset to the right with respect to the longitudinal axis of the inner thread315or the tensioning pin210. This offset is identified by “V” inFIGS. 24 and 25.

If a tool adapter500-504tensioned in the inner cone310is to be removed from the inner cone310, then the tensioning pin210is also rotated out of the recess317in this exemplary embodiment. If the tensioning pin210is rotated further out of the recess317after it has reached the frustoconical countersink318that is arranged offset (seeFIG. 25), a force acts in the axial direction on the driver ring220(to the left inFIG. 25). This axial force is transmitted via the form-locking elements222to the collar321of the tool adapter500-504and presses it out of the inner cone310.

In order to reduce the surface pressure between the frustoconical countersink318and the tensioning pin210, a chamfer319or a rounding can be attached to the tensioning pin210.

It is also possible that the through bore225of the driver ring220is designed as a stepped bore (seeFIGS. 7 and 8) and that the transition between the two bore diameters is designed as a frustoconical countersink318. This variant is not shown in the figures. Their mode of operation corresponds to that of the exemplary embodiment according toFIGS. 24 and 25.

The “V” function depends on the offset “V” between the longitudinal axis of the inner thread315or the tensioning pin210and the countersink318.

It is possible to arrange the through bore225coaxially with the longitudinal axis of the inner thread315or coaxially with the countersink3318. In the first case, there is a somewhat “nicer” look because the tensioning pin210is centered in the through bore225for the user. In the second case, the production is a little easier.

LIST OF REFERENCE NUMERALS

100spindle101straight driven tool102angled driven tool103square shank for turning with tool holder104round shank or spindle with tool holder200tool holder in the tool mount210tensioning pin220driver ring with form-locking element(s)221groove in the tool mount222form-locking element223groove in the tool adapter224cylindrical section225through bore230outer thread300collet holder310inner cone of the collet holder311flat surface/flat system on the collet holder312front end313rear end314cylindrical bore315inner thread316truncated cone317recess318frustoconical countersink319chamfer on tensioning pin210320outer cone on the tool adapter321collar/flat surface on the tool adapter322polygon323projection325axial groove326groove330clear bore340tool holder on the tool adapter400collet401tensioning nut402screw plug500tool adapters with cutting tool holder501tool adapter as turning tool502tool adapter with integrated cutting tool503tool adapter as sealing plug504tool adapter as drill rod tool505twist drill600driven tool mounts700fixed tool mount