Title of Invention

TOOL COUPLER FOR CONNECTING A REPLACEABLE TOOL HEAD TO A MACHINE TOOL .

Abstract

The invention relates to a tool coupling for connecting a removable tool head to a machine tool. Said tool coupling comprises an at least partly or fully conical or cylindrical hollow shaft (10) and an annular resting collar (12) which cooperate with a correspondingly configured receiving bore and an annular opposite surface of a basic holder located on a machine tool. The basic holder and the tool coupling can be locked by means of clamping elements which can be actuated via a clamping device such that the resting collar (12) of the tool coupling leans on the opposite surface of the basic holder. The invention tool coupling further comprises a circumferential gripping groove (13) for a gripping device during automatic tool replacement. According to the invention, two diametrically opposed blind hole bore (14, 15) having different bore hole contours are arranged inside the gripping groove (13).

Full Text

Tool Coupler The invention relates to a tool coupler for connecting a replaceable tool head to a machine tool comprising an at least partly or fully conical or cylindrical hollow shaft and a ring-shaped collar interacting with a correspondingly configured receiving bore hole and a ring-shaped opposite surface of a basic holder on a machine tool, where the basic holder and the tool coupler can be locked by means of clamping elements actuated via a clamping device in such a way that the collar of the tool coupler abuts on the opposite surface of the basic holder, and the tool coupler is provided with a continuous gripper groove for a gripping device used in automatic tool replacement. Couplers of this type are known, for example, from EP 0 343 190 B1 where the latter coupler works with balls as clamping elements, which are driven via a tension rod radially outward when the tool is mounted and radially inward when the tool is removed into existing openings. Another comparable tool coupler with wedge-shaped clamping elements is shown and described in DE 38 07 140 C2. The combination of a hollow cone shaft, which, compared to the respective receiving bore hole is slightly overdimensioned in the range of elastic deformation, with the mutual flat abutment achieves high axial rigidity under static and dynamic load forming a tool coupler for connecting a tool holder and a basic holder, possibly in the form of a machine tool spindle seat, which is useable in tool machines for turning, drilling and milling. As a result, the machine tool can be used as a machining center for many different cutting operations. In fully automated production, the so-called tool replacement systems are becoming increasingly important where, instead of manually replacing the tool, a gripper groove is provided on the tool head or on the tool coupler for replacing the tool head. However, in order to precisely adjust the tool head and tool coupler, which may also be separate intermediate piece for seating and mounting a tool head, in a machine tool spindle or a basic holder on the one hand and a tool magazine, such as a revolving disk, on the other hand, with regard to the angle of rotation, further positioning elements are required. According to prior art, catches or other switching areas and locating faces disposed on the outside surface of the tool coupler are used in connection with positioning elements, such as pins in the basic holder or a machine spindle. In order to orient the tool coupler in the magazine on the one hand and in the tool coupler seat on the other hand and for preventing 180° misalignments, such switching areas and locating faces are provided on diametrically opposite surface areas of the tool coupler. For the tool carrier according to EP 1 007 265 Bl, diametrically opposite recesses are used, which have to be configured with varying geometry for the above mentioned reasons. The unbalance resulting from said configuration manifests itself especially in tools rotating at high speed. In order to compensate said source of unbalance and other unbalances resulting from asymmetrical tool coupler configurations, it is proposed for the tool carrier according to EP 1 007 256 Bl to provide one or more bore holes on the inside of the tool carrier. However, the tool carrier of EP 1 007 256 B1 is disadvantageous in that it matches only one certain machine tool type. Further, reference may be made to DE 3916315 and EP 1339014. DE 3916315 is directed to a tool shank for milling cutters, end mills, boring tools, tool holders, etc. This is produced with a regular curviliear polygonal collar which engages positively with a matching bore in the spindle nose and permits high rotational speeds in the range 10,000 to 100,000 rpm without slipping. Alternatively, the drive may be transmitted by a collar having backwards pointing gear formed teeth which engage with corresponding teeth on the end face of the spindle nose. The groove has diametrically opposed holes which can be engaged by Hie gripper mechanism of an automatic tool changer. The small gap (a) between the flange and spindle nose is witness that the taper shank is properly seated. EP 1339014 relates to an information-holding unit which can minimize increase in cost and which can increase storage capacity as a whole without changing information transferring time. The information-holding unit comprises a plurality of RFID tags with desired specific information stored therein, and a tool holder as a mounting body for mounting these plural RFID tags. Yet further, reference may be made to XP 241534 and DE 3326615 relating to tool couplings comprising of a microchip arranged in the gripping groove and having a readable memory. However, a diametrically opposite hole is neither disclosed nor suggested in order to avoid unbalance. The objective of the present invention is to improve the tool coupler so as to provide an alternative that is universally useable for multiple types of machines and allowing maximum position accuracy for the angle of rotation with maximum weight compensation so as to prevent unbalanced when the tool is replaced automatically. According to this invention there is provided a tool coupler for connecting a replaceable tool head to a machine tool comprising an at least partly or fully conical or cylindrical hollow shaft and a ring-shaped collar interacting with a correspondingly configured receiving bore hole and a ring- shaped opposite surface of a basic holder on the machine tool, where the basic holder and the tool coupler can be locked by means of clamping elements actuated via a clamping device in such a way that the collar of the tool coupler abuts on the opposite surface of the basic holder, and the tool coupler is provided with a continuous gripper groove for a gripping device used in automatic tool replacement, characterized in that the gripper groove is provided with two diametrically opposite blind bore holes with varying bore hole contours, and additionally, two more diametrically opposite blind bore holes are provided wherein one of the additional blind bore holes is provided with a microchip comprising a readable memory with information for tool identification or coding. The problem is solved by means of the tool coupler, where, in accordance with the invention, the gripper groove is provided with two diametrically opposite blind bore holes with varying bore hole contours. In contrast with the solutions of the prior art, the diametrically opposite arrangement of the bore holes in the groove largely counteracts the unbalance. Additional bore holes for compensation of unbalance weakening the body of the coupler otherwise are not required, which advantageously simplifies the manufacture of such tool couplers. The advantageously conical configuration of the hollow shaft in connection with the flat abutment and the radially outward moving clamping elements for clamping the tool coupler, especially clamping balls, which are subjected to centrifugal forces when the tool rotates, achieves dynamic rigidity in addition to static rigidity and prevents unbalance up to high speeds. Furthermore, the varying contours of the diametrically opposite blind bore holes can be made such that, both statically and dynamically (under rotation), the "mass removed" via the recesses is fully or at least substantially compensated. The blind bore holes are further advantageous in that they, in connection with positioning pins, allow an accurate tool coupler adjustment, both axially and with regard to the angle of rotation, so that tool misalignments are virtually impossible. Refinements of the invention are described in the sub-claims. For example, the blind bore holes are advantageously disposed centrically relative to the gripper groove, and as a further advantage, their diameter is greater, at least in the top area, than the width of the groove. According to another embodiment of the invention, in cross section, the blind bore holes can have to top area, which is wider in diameter and an additional area with a smaller diameter joining the bore hole bottom, advantageously, the diameter in the upper area are identical. The bottom area of the step-like configured blind bore hole uniformly has a smaller, but possibly different diameter on opposite sides. Accordingly, one of the blind bore holes may have a smaller diameter in the bottom area and a greater depth, and vice versa, on the other side, it may have a comparatively greater diameter, but a lesser depth. The varying geometry can also be realized by means of a partly conical bore hole bottom or a flat bore hole bottom, thereby effectively preventing 180° errors in the angle of rotation for the tool coupler of the invention. Furthermore, for automated tool replacement, it is desirable that the respective tool or tool head can be automatically identified. According to prior art, readable microchips integrated on or in the tool coupler are available for tool identification. Maximum readability is ensured when the microchips are provided on the outside surface of the body of the respective carrier. If, according to a further embodiment of the invention, a tool coupler is used with two additional diametrically opposite blind bore holes disposed so as to be offset by 90° relative to the above described blind bore holes (with varying contours), the microchip can be mounted in one of said bore holes. The resulting radial inward move adequately protects the microchip against external mechanical effects. Such additional diametrically opposite bore holes have an identical or substantially identical contour. While one of the additional bore holes serves to receive the microchip, the opposite bore hole eliminates the static dynamic unbalance. Advantageously, said two bore holes are configured flat, which means they have a greater diameter than the measure of their depth. The diameter of the bore holes can be identical to the diameter of the top areas of the two blind bore holes with varying contours. If required, however, each of said additional bore holes can be used in the manner described above with respect to the blind bore holes, so that in principle, four bore holes, offset by 90° can be used for positioning or adjusting the tool head. According to another embodiment, the whole of the four existing blind bore holes in the form of two diametrically opposite bore hole pairs is configured such that the tool coupler is fully balanced. Depending on the intended use, the tool couplers can vary in size matching the size of the spindle or other adapters and intermediate pieces that are used. The standard system sizes range between 32 mm and 160 mm, preferably between 40 mm and 100 mm. The standard diameters are between 40 mm and 80 mm. Depending on the diameter of said tool couplers, a greater or smaller diameter is used for the blind bore holes. Advantageously, the diameters range between 10 mm and 20 mm, especially between 10 mm and 16 mm. According to another embodiment of the invention, based on a frontal view of the tool coupler, the blind bore holes with varying contours are disposed on a vertical plane relative to the connecting line of the openings in the hollow shaft for locking the clamping elements. Accordingly, the additional blind bore holes, one of which carries the microchip, are offset by 90°. An exemplary embodiment of the invention is illustrated in the drawings, as follows: Fig. 1 is a perspective view of a tool coupler of the invention; Figs. 2 and 3 are side views of said tool coupler, offset by 90°; Fig. 4 is a sectional view of said tool coupler in the area of the blind bore holes, and Figs. 5 to 7 are the cross-sections of the respective blind bore holes. The tool coupler illustrated in Fig. 1 has a hollow shaft 10 with a conical outside surface provided with opposite openings 11 by means of which the tool coupler can be mounted in a machine spindle in connection with ball-shaped clamping elements (not shown). Furthermore, the tool coupler has a ring-shaped collar interacting with a correspondingly configured ring-shaped opposite surface of a basic holder on the machine tool. Tool couplers of this kind have been described in detail in EP 0 343 190 B1, for example. In addition, the tool coupler is provided with a substantially V-shaped continuous gripper groove 13 in which a gripping device (not shown) engages when the tool is replaced. On the side opposite the hollow shaft 10, the actual tool head is mounted for carrying the tool (not shown). According to the invention, the tool coupler is provided with two first diametrically opposite blind bore holes 14 and 15 whose varying cross-sections are illustrated in Figs. 5 and 6. Said bore holes or their connecting line is vertical relative to the connecting line of the two above described openings 11 in the hollow shaft 10. Flat bore holes 16 with the same contours are offset by 90° and diametrically opposite. Their connecting line is disposed parallel to the connecting line of the two openings 11. The bore hole 16 shown in Fig. 1 serves as a compensating bore hole for eliminating the unbalance which would be generated if the opposite bore hole 16, in which the microchip is disposed, were the only one. Said microchip comprises a data memory containing the identification codes for the respective tool. The bore holes 14, 15 and 16 are disposed centrically relative to the gripper groove, as illustrated by Figs. 2 and 3. In this case, the bore hole 16 has a substantially uniform diameter a of 10 mm with a lesser bore hole depth b of 5.4 mm. As shown in Fig. 7, however, the bore hole may deviate slightly from a cylindrical form and taper conically toward the open side. 'A microchip is disposed in one of the bore holes 16 and comprises a memory with readable information for tool identification. Said microchip arrangement in the bore hole 16 protects the microchip against external mechanical damage. The bore holes 14 and 15, on the other hand, have varying contours. According to a special exemplary embodiment, the top area 17 of said bore holes 14 and 15 has the same contour as bore hole 16. It is joined by a bottom area 18 or 19. The bore hole 14 shown in Fig. 5 has a bottom area 18 with a cylindrical area joined by a conically configured bore hole bottom 20. Said bore hole 14 is used for the controlled positioning of the tool coupler in the seat provided in the machine (spindle or basic holder), where it can be determined, for example by means of spring-loaded pins with a conical end in the basic holder, when the tool coupler and thus the tool head have reached the position with the desired angle of rotation. The opposite bore hole 15 instead has a cylindrical bottom area 19 with a smaller diameter than the top area 17, but the bore hole is considerably flatter, i.e. it has a lesser depth. The bore hole 15, in connection with respective positioning pins, serves to orient the tool coupler in a magazine. WE CLAIM; 1. Tool coupler for connecting a replaceable tool head to a machine tool comprising an at least partly or fully conical or cylindrical hollow shaft (10) and a ring-shaped collar (12) interacting with a correspondingly configured receiving bore hole and a ring-shaped opposite surface of a basic holder on the machine tool, where the basic holder and the tool coupler can be locked by means of clamping elements actuated via a clamping device in such a way that the collar (12) of the tool coupler abuts on the opposite surface of the basic holder, and the tool coupler is provided with a continuous gripper groove (13) for a gripping device used in automatic tool replacement, characterised in that the gripper groove (13) is provided with two diametrically opposite blind bore holes (14, 15) with varying bore hole contours, and additionally, two more diametrically opposite blind bore holes (16) are provided wherein one of the additional blind bore holes is provided with a microchip comprising a readable memory with information for tool identification or coding. 2. Tool coupler as defined in claim, characterized in that the blind bore holes (14, 15) are disposed centrically relative to the gripper groove (13) and/or have a maximum diameter that is greater than the width of the groove. 3. Tool coupler as defined in claims 1 or 2, characterized in that in cross- section the blind bore holes have a top area (17) wider in diameter and a bottom area (18, 19) with a smaller diameter joining the bore hole bottom. 4. Tool coupler as defined in claim 3, characterized in that the bore hole bottom of one of the blind bore holes is flat and that of the other blind bore hole configured at least partly conically. 5. Tool coupler as defined in any of the claims 1 to 4, characterized in that additionally, two more diametrically opposite blind bore holes (16) are provided disposed so as to be offset by 90° from the blind bore holes (14, 15) with varying bore hole contours. 6. Tool coupler defined in claim 5, characterized in that the additional blind bore holes (16) are greater in diameter (a) than in depth (b). 7. Tool coupler as defined in any of the claims 1 to 6, characterized in that the blind bore holes (14, 15 and 16) are made such that the tool coupler is statically any dynamically balanced. 8. Tool coupler as defined in any of the claims 1 to 7, characterized in that, at least in the top area, the diameter of the blind bore holes (14, 15) and/or of the additional blind bore holes (16) is between 10 mm to 20 mm, advantageously between 10 mm to 16 mm. 9. Tool coupler as defined in any of the claims 1 to 8, characterized in that based on a frontal view, the blind bore holes (14, 15) with varying bore holes contours are provided on a vertical plane relative to the connecting line of the openings (11) in the hollow shaft (10) for locking the clamping elements. The invention relates to a tool coupling for connecting a removable tool head to a machine tool. Said tool coupling comprises an at least partly or fully conical or cylindrical hollow shaft (10) and an annular resting collar (12) which cooperate with a correspondingly configured receiving bore and an annular opposite surface of a basic holder located on a machine tool. The basic holder and the tool coupling can be locked by means of clamping elements which can be actuated via a clamping device such that the resting collar (12) of the tool coupling leans on the opposite surface of the basic holder. The invention tool coupling further comprises a circumferential gripping groove (13) for a gripping device during automatic tool replacement. According to the invention, two diametrically opposed blind hole bore (14, 15) having different bore hole contours are arranged inside the gripping groove (13).

Documents:

129-KOLNP-2006-(07-08-2012)-CORRESPONDENCE.pdf

129-KOLNP-2006-(07-08-2012)-PA.pdf

129-KOLNP-2006-(27-02-2012)-CORRESPONDENCE.pdf

129-KOLNP-2006-(27-02-2012)-FORM-13.pdf

129-KOLNP-2006-(27-02-2012)-FORM-27.pdf

129-KOLNP-2006-(27-02-2012)-PA-CERTIFIED COPIES.pdf

129-KOLNP-2006-CORRESPONDENCE.pdf

129-KOLNP-2006-FORM 27.pdf

129-kolnp-2006-granted-abstract.pdf

129-kolnp-2006-granted-claims.pdf

129-kolnp-2006-granted-correspondence.pdf

129-kolnp-2006-granted-description (complete).pdf

129-kolnp-2006-granted-drawings.pdf

129-kolnp-2006-granted-examination report.pdf

129-kolnp-2006-granted-form 1.pdf

129-kolnp-2006-granted-form 18.pdf

129-kolnp-2006-granted-form 2.pdf

129-kolnp-2006-granted-form 26.pdf

129-kolnp-2006-granted-form 3.pdf

129-kolnp-2006-granted-form 5.pdf

129-kolnp-2006-granted-pa.pdf

129-kolnp-2006-granted-reply to examination report.pdf

129-kolnp-2006-granted-specification.pdf

129-kolnp-2006-granted-translated copy of priority document.pdf