Title of Invention

A MACHINE TOOL PARTICULARLY A MILLING-CUM-DRILLING MACHINE

Abstract

The invention relates to a machine tool, particularly a milling -cum-drilling machine, comprising a rigid base (1) on which an inclined support surface (8) pointing forwards and upwards is formed, at least one workpiece support (10) rotatable about the central axis (15) of the support surface (8) serving as support and comprising a support (12) supported on the support surface (8) so as to be rotatable about its central axis (15) and a workpiece table (14) disposed on a bent support element (13) of the support and movable into a horizontal and a vertical basic position by rotating the workpiece support (10) and at least one machining unit (6) shiftable along coordinate axes and having an exchangeable tool. The support surface (8) is laterally offset with respect to the vertical central plane (32) of the base (1) so that its central axis (15) forms an acute spatial angle θ, with a vertical longitudinal plane (32) of the base (1) and in that the workpiece table (14) assumes a forwardly tilted position in the intermediate positions within a rotational angle range.

Full Text

FIELD OF INVENTION The invention relates to a machine tool, particularly a milling and drilling machine comprising a rigid base on which an inclined support surface directed forwards/upwards is formed, at least one workpiece support rotatable about the central axis of said support surface and including a support supported on the support surface so as to be rotatable about its central axis and a workpiece table provided on a bent support portion of the base, the axis of said workpiece table forming an acute angle with the central axis of the support surface, and at least one machining unit shiftable along coordinate axes and including exchangeable tools. BACKGROUND OF INVENTION From the EP 0 721 819 B1 a milling and drilling machine for machining a workpiece in a plurality of axes in one clamping is known which comprises a machining unit shiftable along coordinate axes on a rigid machine column by means of a motor and including a vertical spindle head. On the front surface of the machine column a recess is provided the bottom of which, extending forwards and upwards by 45°, serves as a support surface for the support of a workpiece support. The support is rotatable about the central axis of the support surface which is inclined by 45°, and it comprises an, as viewed from above, circular foot as well as a support shoulder formed integrally therewith. A support surface formed on said support shoulder is inclined by 45° with respect to the rotational axis of the support and serves as a support surface for a workpiece table which may be formed as a round table rotatable about its central axis by means of a motor. The recess and its bottom extending forwards and upwards by 45° as well as the workpiece support rotatably supported thereon are disposed on the machine column in its vertical central plane. By rotating the workpiece support about its central axis on the support surface the workpiece table can be turned into a horizontal machining and clamping position, a vertical position as well as intermediate postures and fixed in each of said positions so that a clamped workpiece can be machined by means of the vertical spindle in a plurality of axes in one clamping. However, no back surface undercuts may be produced with this machine. Other machine tools comprising workpiece supports rotatably disposed on a surface inclined by 45° are, for example, known from the DE 3590 093 T and from the US 4644 635. On these machines the workpiece table can also be moved from a horizontal position into a vertical position by means of a motor so that a clamped workpiece can be machined vertically and horizontally. OBJECT OF INVENTION It is the object of the invention to provide a machine tool, particularly a milling and drilling machine having an extended machining area and in particular enabling back surface undercuts on a workpiece. SUMMARY OF INVENTION According to the invention said object is solved by disposing the support surface extending obliquely forwards and upwards and serving as a support for the workpiece support laterally offset with respect to the vertical central plane of the base so that its central axis forms an acute angle with the vertical central plane of the base and the workpiece table assumes a posture in which it is tilted forward in an intermediate position within a rotational angle range. In case of the machine tool designed in accordance with the invention the workpiece table can be moved into a vertical position as well as intermediate postures from a horizontal posture by a rotation of the workpiece support, i.e. the base including the workpiece table, about the central axis of the laterally offset, inclined support surface and accurately and stably fixed in each of said positions by suitable fixation means, for example in the form of clamping elements, centring studs and / or position controlled motors. In the horizontal and vertical basic positions work can be carried out in the way known from the cited EP 0721 819 B1. The advantages of this known milling and drilling machine over conventional machine types, such as the convenient accessibility of the work space, the stable support of the workpiece support on the base due to the large bearing surface of the base on the support surface, are also given in the machine tool according to the invention. According to the invention the new machine additionally provides the possibility to move the workpiece table, within a predetermined rotational angle range, into a forward tilted posture in which the back surface of clamped workpieces can be machined by means of a simple vertical spindle-without a pivotable head- and, for example, undercuts can be produced in the workpiece. According to an efficient embodiment of the invention the angle between the central axis of the support surface forming the rotational axis of the workpiece support and the axis of the workpiece table in the vertical plane extending through said central axis is greater than 45° in a predetermined range, a certain maximum degree of overhang of the workpiece table being obtained by determining this angle. The degree of the lateral offset of the workpiece support and the inclined spatial orientation of its central axis are determined in accordance with this angle. To increase the productivity a further development of the invention is characterized in that two workpiece supports are provided on two inclined support surfaces disposed on both sides of the vertical central plane of a base. In this way a workpiece may be clamped to the second workpiece table while another one is machined. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS. An embodiment of the invention will be described in detail below with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a milling and drilling machine; Figs 2a to 2c, show the base of a milling and drilling machine as well as a workpiece support in various operating positions; Fig. 3 is a schematic top view of the base of a milling and drilling machine and the workpiece support; Fig. 4 is a schematic side view of the workpiece support. DETAIL DESCRIPTION OF THE INVENTION The universal milling and drilling machine shown in Fig. 1 comprises a rigid base 1 resting on the floor or foundation via feet 2. On the front side of said base 1 a pan 6 for collecting chips and machining liquids and defined by side walls 3,4 and an inclined rear wall 5 is provided. According to Fig. 1 the pan 6 is defined by an inclined, forwards and upwards pointing support surface 8 at its right side which forms a support for a workpiece support. The support surface 8 is formed laterally offset with respect to the vertical central plane 32 of the base 1 on a lateral portion of the base 1 and oriented so that its spatially obliquely extending central axis 15 forms an acute spatial angle 0 with a vertical longitudinal plane, in this case the vertical central plane 32. The workpiece support 10 comprises a support 11 including a circular foot 12 and a bent support member 13 integrally formed thereon, a workpiece table 14 being mounted on the upper side of said support member 13. The workpiece table 14 may be formed as a rotationally driven round table. The circular foot 12 of the support 11 is extensively supported on the support surface 8 of the base 1 and rotatable about the central axis 15 of the support surface 8 and the support foot 12 extending in the acute spatial angle 8 by means of a motor so that the workpiece support 10 can be rotated about its axis 15 in both senses of rotation. The support 11 can be fixed in any ro- tational position with respect to the support surface 8 by means of fixation means (not shown), e.g. latches, clamping elements or posi- tion controlled electric motors. Further a rounded front recess 16 enabling a collision-free rotation of the workpiece support 10 about the central axis 15 is formed on the face of the base 1 on the, accord- ing to Fig. 1, left side of the inclined support surface 8. According to the milling and drilling machine shown in Fig. 1 a support 20 having, in this case, a U-shaped cross section is mounted on the base 1, a guide rail 21, 22 being mounted on each of the two upper legs of said support 20, respectively. On the guide rails 21, 22 a slide 23 comprising two guide rails provided in a distance to each other on the upper side and serving as supports for a housing 25 shiftable in the direction of the Y-axis, is supported so as to be mov- able along the X-coordinate axis. On the vertical face of the housing 25 a machining unit 26 comprising a driven work spindle 29 having a vertical spindle axis 30 as well as a spindle drive is shiftable in verti- cal guides 27, 28. Instead of the vertical spindle head 26 horizontal spindles and so called pivotable heads comprising a pivotable work spindle may be used. Figs. 2a, b and c show the base 1 including the column 20 and the workpiece support 10 in various perspective views, the workpiece table 14 being respectively located in different positions. According to Fig. 2a the workpiece table 14 is disposed in a horizontal basic posi- tion also shown in Fig. 1 in which workpieces are machined by means of the vertical spindle 29. Of the work spindle only the spindle axis 30 is indicated by a bold broken line here. As can be seen from Figs. 1 and 2a the clamping grooves in the workpiece table 14 do not - as usually - extend parallel to the X- or Y-coordinate axis but in an acute angle. When a rotationally driven round table 14 is used the conventional table position with the clamping grooves extending par- allel to the X-coordinate axis as well as any other position of the workpiece table can be obtained by a rotation about the table axis 34. In the second basic position shown in Fig. 2b the workpiece support 10 is rotated about its axis 15 by a predetermined angle on the inclined support surface 8 so that the workpiece table 14 is dis- posed in a vertical position. In the position shown the workpiece table 14 rotatable about its axis 34 is rotated so that its clamping grooves are oriented in the direction of the X-coordinate axis. By rotating the workpiece table 14 all sides of a clamped workpiece can be machined in the conventional way with a tool inserted in the vertical work spin- dle. When the workpiece support 10 is rotated about its rotational axis 15, i.e. the central axis 15 of the support surface 8, by 180° to- gether with the horizontal workpiece table 14 from the basic position shown in Fig. 2a into the position shown in Fig. 2c the workpiece ta- ble 14 and the clamped workpiece (not shown) are moved in a tilted position. A tool clamped in the vertical work spindle indicated by its axis 30 can produce back surface undercuts in this table position. The undercuts can be produced on each side of the workpiece by ro- tating the workpiece table 14 about its central axis 34. This effect is achieved by an interaction of the lateral offset of the workpiece sup- port 10 and the special inclined orientation of its rotational axis 15. In the schematic views shown in Figs. 3 and 4 the angles for the embodiment of the invention shown in detail in Fig. 1 are indicated, the workpiece table 14 being shown in its horizontal basic position. As can be seen in Fig. 3 the angle a between the vertical central plane 32 and the rotational axis 15 of the workpiece support 10 determin- ing the lateral offset of the workpiece support 10 is about 45,6° in the plane of the drawing. Fig. 4 is a schematic side view of the workpiece support 10 in a direction parallel to the oblique surface 8 of the base 1, i.e. in the di- rection of the arrow 33 in Fig. 1, the workpiece table 14 being shown in the horizontal basic position shown in Fig. 1. The workpiece sup- port 10 is formed so that the angle (3 between its rotational axis 15 and the rotational axis 34 of the workpiece table 14 is 55° in the il- lustrated embodiment. The selection and interrelated adjustment of the two angles a and (3 determine the tilting degree of the workpiece table 1.4. A particular advantage of the invention is the relatively large workspace also existing in the intermediate position of the workpiece table 14 shown in Fig. 2c and resulting from the laterally offset posi- tion of the support surface 8 with respect to the central plane 32 in functional connection with the inclined orientation of the workpiece support 10 according to the invention. Further it is advantageous that the milling head 26 moves only along one axis during the ma- chining of the workpiece in the positions of the workpiece support 10 shown e.g. in Fig. 2c. The invention is not limited to the illustrated embodiment. The inclined table arrangement according to the invention may also be used for so-called bed machines in which at least one workpiece sup- port is provided on a machine bed which can be regarded as a part of the machine base. The inclined support surface forming the support for the rotatable workpiece support and having a central axis serving as the rotational axis for the workpiece support and forming an acute spatial angle with a vertical longitudinal plane of the machine bed may be arranged on the machine bed or a column so as to be laterally offset with respect to the vertical central plane of the machine with a correspondingly adjusted oblique orientation of its central axis. Such a column may also be shiftable on the machine bed in corresponding guides. Further two of the workpiece supports described in detail above may be formed on a base, preferably on both sides of the verti- cal central plane. Further the technical concept of the invention may also be ap- plied to machining units of a milling and drilling machine comprising a milling or spindle head. In this case a spatially inclined support surface corresponding the inclined support surface 8 of the machine described above is formed on a vertical or horizontal slide or head- stock guided on the machine column so as to be shiftable along at least one coordinate axis. On said inclined support surface a support is supported so as to be rotatable about its central axis. The central axis of the support surface extends in a spatial angle 9 with respect to a vertical plane. On a bent front or side portion of the support pro- vided opposite of the inclined support surface a spindle head includ- ing a rotationally driven work spindle is provided. The vertical and horizontal orientation of the work spindle as well as, in addition, a plurality of spatially inclined spindle positions, for example for the production of back surface undercuts, are obtained by a suitable se- lection and interrelated adjustment of the spatial angle. The advan- tage compared to known fork heads is the substantially higher overall rigidity due to the extensive support of the pivotable head on the in- clined support surface enabling a high machining performance and accuracy. WE CLAIM: 1. A machine tool, particularly a milling -cum-drilling machine, comprising - a rigid base (1) on which an inclined support surface (8) pointing forwards and upwards is formed, - at least one workpiece support (10) rotatable about the central axis (15) of the support surface (8) serving as support and comprising a support (12) supported on the support surface (8) so as to be rotatable about its central axis (15) and a workpiece table (14) disposed on a bent support element (13) of the support and movable into a horizontal and a vertical basic position by rotating the workpiece support (10) and - at least one machining unit (6) shiftable along coordinate axes and having an exchangeable tool, characterized in that - the support surface (8) is laterally offset with respect to the vertical central plane (32) of the base (1) so that its central axis (15) forms an acute spatial angle 0, with a vertical longitudinal plane (32) of the base (1) and in that the workpiece table (14) assumes a forwardly tilted position in the intermediate positions within a rotational angle range. 2. The machine tool as claimed in claim 1, wherein the workpiece support (10) is designed so that the angle (p) between the central axis (15) of the support surface (8) forming its rotational axis and the central axis (34) of the workpiece table (14) is greater than 45°. 3. The machine tool as claimed in claim 2, wherein the angle (ß) is adjusted together with an angle (a) between the vertical plane (32) and the central axis (15) of the support surface (8) projected into the horizontal plane also determining the lateral offset of the support surface (8) to obtain a desired degree of tilting. 4. The machine tool as claimed in one of the preceding claims, wherein the workpiece table (14) is rotationally driven. 5. The machine tool as claimed in one of the preceding claims, wherein the base is a machine column (1) comprising a recess (16) provided on its front surface and disposed laterally with respect to the vertical central plane (32) of the base (1), the bottom of said recess (16) forming at least part of the support surface (8) of the rotatable workpiece support (10). 6. The machine tool as claimed in claim 5, wherein the machine column (1) comprises a slide arrangement (23,25) shiftable along the horizontal coordinate axes (X,Y), the machining unit (6) comprising a milling head and a vertical work spindle (29) being mounted on said slide arrangement (23,25) so as to be shiftable along the vertical coordinate axis (Z). 7. The machine tool as claimed in one of the claims 1 to 4, wherein the base is a machine bed on which at least one workpiece support (10) is fixedly or shiftably provided. 8. The machine tool as claimed in one of the preceding claims, wherein two workpiece supports (10) are provided on a base (1) on two inclined support surfaces respectively disposed on both sides of the central plane (32). The invention relates to a machine tool, particularly a milling -cum-drilling machine, comprising a rigid base (1) on which an inclined support surface (8) pointing forwards and upwards is formed, at least one workpiece support (10) rotatable about the central axis (15) of the support surface (8) serving as support and comprising a support (12) supported on the support surface (8) so as to be rotatable about its central axis (15) and a workpiece table (14) disposed on a bent support element (13) of the support and movable into a horizontal and a vertical basic position by rotating the workpiece support (10) and at least one machining unit (6) shiftable along coordinate axes and having an exchangeable tool. The support surface (8) is laterally offset with respect to the vertical central plane (32) of the base (1) so that its central axis (15) forms an acute spatial angle θ, with a vertical longitudinal plane (32) of the base (1) and in that the workpiece table (14) assumes a forwardly tilted position in the intermediate positions within a rotational angle range.

Documents:

907-KOL-2005-(18-10-2012)-FORM-27.pdf

907-kol-2005-granted-abstract.pdf

907-kol-2005-granted-claims.pdf

907-kol-2005-granted-correspondence.pdf

907-kol-2005-granted-description (complete).pdf

907-kol-2005-granted-drawings.pdf

907-kol-2005-granted-examination report.pdf

907-kol-2005-granted-form 1.pdf

907-kol-2005-granted-form 18.pdf

907-kol-2005-granted-form 2.pdf

907-kol-2005-granted-form 3.pdf

907-kol-2005-granted-form 5.pdf

907-kol-2005-granted-pa.pdf

907-kol-2005-granted-priority document.pdf

907-kol-2005-granted-reply to examination report.pdf

907-kol-2005-granted-specification.pdf

907-kol-2005-granted-translated copy of priority document.pdf