MACHINE TOOL WITH TWO INDEPENDENT CARRIAGES

Abstract

A machine tool has a substantially straight guide element extending along a first axis; two carriages, which are arranged at a fixed distance from one another along the guide element and are capable of sliding together along the guide element; a slide, which is interposed between the two carriages, is carried by the two carriages and can slide relative to them along a second axis perpendicular to the first axis; and a milling head, which is carried by the slide and is configured to carry a milling tool.

Claims

1. Machine tool comprising: a substantially straight guide element (2) extending along a first axis (A1); two carriages (3, 4) arranged at a fixed distance (D) with respect to each other along the guide element (2) and slidable together along the guide element (2); and a slide (5) interposed between the two carriages (3, 4), carried by the two carriages (3, 4) and slidable in relation to the two carriages (3, 4) along a second axis (A2) perpendicular to the first axis (A1); wherein said carriages (3, 4) are independent and mechanically linked together solely by said slide (5).

2. Machine tool as claimed in claim 1, comprising a machining head (6) carried by the slide (5) and configured to carry a machining tool.

3. Machine tool as claimed in claim 1, where the guide element (2) comprises at least one rail (7; 8) extending in a direction parallel to the first axis (A1), and each of the carriages (3, 4) comprises at least one runner (10) coupled to the rail (7, 8) slidably along the direction of the first axis (A1) and rigidly in a direction perpendicular to the first axis (A1).

4. Machine tool as claimed in claim 1, wherein the guide element (2) comprises a first rack (9) extending in a direction parallel to the first axis (A1); at least one of the two carriages (3, 4) comprising at least one motor (11; 12) fitted with a toothed wheel (13) which engages with the first rack (9).

5. Machine tool as claimed in claim 4, wherein one of the two carriages (3, 4) comprises a first motor (11) and the other of the two carriages (3, 4) comprises a second motor (12), the first and second motors (11, 12) being fitted with respective toothed wheels (13) which mesh with the first rack (9) and are configured to exert respective torques in opposite directions upon the respective toothed wheels (13).

6. Machine tool according to claim 5, wherein the first and the second motor (11, 12) are configured to control, in a coordinated manner, the torques exerted upon the respective toothed wheels (13) so as to modulate the stiffness of the connection between the carriages (3, 4) and the slide (5) in a direction substantially parallel to the first axis (A1).

7. Machine tool as claimed in claim 1, wherein the slide (5) comprises at least two rails (14, 15), each of which is facing the respective carriage (3; 4) and extends in a direction parallel to the second axis (A2); each carriage (3; 4) being fitted with at least one slider (16) coupled to the respective rail (14, 15) in a sliding way along the direction of the second axis (A2) and substantially rigid in a direction perpendicular to the second axis (A2).

8. Machine tool as claimed in claim 4, wherein the slide (5) comprises a second rack (17) extending in the direction parallel to the second axis (A2); at least one of the two carriages (3; 4) comprising at least one motor (18; 19) fitted with a toothed wheel (20) which engages with the second rack (17).

9. Machine tool as claimed in claim 8, wherein one of the two carriages (3; 4) comprises a third motor (18) and a fourth motor (19), which are fitted with their respective toothed wheels (20) which engage with the second rack (17) and are configured to exert their respective torques in opposite direction upon the respective toothed wheels (20).

10. Machine tool as claimed in claim 8, wherein one of the two carriages (3, 4) comprises a third motor (18) and the other of the two carriages (3, 4) comprises a fourth motor (19), said third and fourth motors (18, 19) being fitted with respective toothed wheels (20) which mesh with the second rack (17) and are designed to exert respective torques in opposite directions upon the respective toothed wheels (20).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Further features and advantages of the invention will be best understood upon perusal of the following description of a non-limiting embodiment thereof, with reference to the accompanying Figures, wherein:

[0035] FIG. 1 is a perspective, partial view of a machine tool according to the invention;

[0036] FIG. 2 is a front view of the machine tool of FIG. 1;

[0037] FIG. 3 is a side elevation view of the machine tool of FIG. 1;

[0038] FIG. 4 is a top view of the machine tool of FIG. 1;

[0039] FIG. 5 is a sectional view of the machine tool of FIG. 1 along section lines V-V;

[0040] FIG. 6 is a sectional view of the machine tool of FIG. 1 along section lines VI-VI; and

[0041] FIG. 7 is a partially sectional, plan view of a further variant of the machine tool of FIG. 1.

PREFERRED EMBODIMENT OF THE INVENTION

[0042] With reference to FIGS. 1 and 2, number 1 indicates, as a whole, a machine tool, in particular a milling machine, preferably a CNC milling machine. The milling machine 1 comprises a substantially straight guide element 2 extending along an axis A1, for example a horizontal one; two carriages 3 and 4, which are arranged at a fixed distance D from one another along the guide element 2 and are capable of sliding together along the guide element 2; a slide 5, which is interposed between the carriages 3 and 4, is carried by the carriages 3 and 4 and can slide relative to the carriages 3 and 4 along an axis A2 perpendicular to the axis A1, in particular a vertical one; and a milling head 6, which is carried by the slide 5 and is configured to carry a milling tool (which is not shown in the accompanying Figures).

[0043] The guide element 2 is supported by a fixed or movable support structure, which is not shown in the accompanying figures because it is not part of the invention. In particular, said support structure can assume different configurations. By way of example, the support structure comprises two vertical supports, each fixed to a respective end of the guide element 2, so as to define a gantry milling machine 1.

[0044] With reference to FIGS. 1-3, the guide element 2 comprises a rail 7 and a rail 8, each extending in a direction that is substantially parallel to the axis A1. In particular, the rails 7 and 8 have a section shaped like a dovetail.

[0045] According to a variant of the invention, which is not shown in the accompanying Figures, the guide element 2 can comprise only one rail extending in a direction parallel to the axis A1. The number of rails of the guide element 2 can change and is not limited by the invention.

[0046] With reference to FIGS. 3 and 5, the guide element 2 comprises a rack 9 extending in a direction that is parallel to the axis A1 and, hence, parallel to the rails 7 and 8.

[0047] With reference to FIGS. 3, 4 and 6, each one of the carriages 3 and 4 comprises four runners 10, two of them being configured to slide on the rail 7 and the other two being configured to slide on the rail 8. In particular, each runner 10 is shaped so as to be coupled to the dovetail-shaped section of the rails 7 and 8 in a sliding manner along the direction of the axis A1 and in a rigid manner in the directions orthogonal to the axis A1, so as to only allow the carriages 3 and 4 to slide along the rails 7 and 8 and avoid the relative movement of the carriages 3 and 4 relative to the guide element 2 in all other directions.

[0048] According to a variant of the invention, which is not shown in the accompanying Figures, each carriage 3 and 4 is provided with only two runners 10, one of them being configured to slide on the rail 7 and the other one being configured to slide on the rail 8. The number of runners 10 of the two carriages 3 and 4 can change and is not limited by the invention.

[0049] With reference to FIGS. 1-5, the carriage 3 comprises an electric motor 11 and the carriage 4 comprises an electric motor 12. Each electric motor 11, 12 is provided with a respective toothed wheel 13 (FIGS. 3 and 5), which meshes with the rack 9 (FIGS. 3 and 5).

[0050] In particular, the motors 11 and 12 are configured to exert respective torques in opposite directions upon the respective toothed wheels 13 (FIGS. 3 and 5) so as to limit the clearances of the coupling between the toothed wheels 13 (FIGS. 3 and 5) and the rack 9 (FIGS. 3 and 5).

[0051] With reference to FIGS. 1-7, the slide 5 is oblong in the direction A2, has a substantially rectangular section and comprises at least two rails 14 and 15, each facing the respective carriage 3, 4 and extending in a direction that is parallel to the axis A2. In particular, the rails 14 and 15 have a section shaped like a dovetail.

[0052] Each carriage 3, 4 comprises at least one slider 16, which is configured to slide along the respective rail 14, 15. In particular, each slider 16 is shaped so as to be coupled to the dovetail-shaped section of the rails 14 and 15 in a sliding manner along the direction of the axis A2 and in a rigid manner in the directions orthogonal to the axis A2, so as to only allow the slide 5 to slide along the axis A2 and avoid the relative movement of the slide 5 relative to the carriages 3 and 4 in all other directions.

[0053] In the specific case described and shown herein, the slide 5 comprises two rails 14 and two rails 15. The carriage 3 comprises eight sliders 16, four of them being configured to slide on one of the two rails 14 and four of them being configured to slide on the other one of the two rails 14. The carriage 4 comprises eight sliders 16, four of them being configured to slide on one of the two rails 15 and four of them being configured to slide on the other one of the two rails 15. The number of rails 14 and 15 and of sliders 16 can change and is not limited by the invention.

[0054] With reference to FIG. 4, the slide 5 comprises two racks 17, each extending in a direction that is parallel to the axis A2 and, hence, parallel to the rails 14 and 15.

[0055] Furthermore, the carriage 3 comprises an electric motor 18 and the carriage 4 comprises an electric motor 19. Each electric motor 18, 19 is provided with a respective toothed wheel 20, which meshes with the respective rack 17.

[0056] In particular, the motors 18 and 19 are configured to exert respective torques in opposite directions upon the respective toothed wheels 20 so as to limit the clearances of the coupling between the toothed wheels 20 and the rack 17.

[0057] According to a variant of the invention, which is not shown in accompanying Figures, the sole carriage 3 comprises a motor.

[0058] With reference to FIGS. 1-3, the milling head 6 comprises two bodies 21 and 22, which are articulated to one another, and a milling tool, which is carried by the body 22 and is not shown in the accompanying Figures.

[0059] In particular, the body 21 is connected to the slide 5 so as to rotate relative to the slide 5 around the axis A2 and the body 22 is connected to the body 21 so as to slide relative to the body 21 around an axis A3 that is perpendicular to the axis A2.

[0060] Furthermore, the milling head 6 comprises motors and/or actuators, which are not shown in the accompanying Figures and are configured to move the bodies 21 and 22 and to start the rotation of the milling tool, which is not shown in the accompanying Figures.

[0061] In FIGS. 1-7, the axis A1 of the guide element 2 is horizontal and the axis A2 is vertical; according to a variant of the invention, which is not shown in the accompanying Figures, the axis A1 could be vertical and the axis A2 could be horizontal.

[0062] In use and with reference to FIGS. 1-4, the motors 11 and 12 start the sliding of the carriages 3 and 4 along the guide element 2. In particular, in order to start the sliding of the carriages 3 and 4 in a first direction, the power of one of the motors 11 and 12 is increased so as to increase the torque of one of the two motors 11 and 12 compared to the other one of the two motors 11 and 12. In order to start the sliding of the carriages 3 and 4 in a second direction, which is contrary to the first direction, the power of the other one of the two motors 11 and 12 is increased.

[0063] In particular, the motors 11 and 12 control, in a coordinated manner,

the torques exerted upon the respective toothed wheels 13 so as to modulate the stiffness of the connection between the carriages 3, 4 and the slide 5 depending on the forces involved.

[0064] Similarly, the motors 18 and 19 start the sliding of the slide 5 relative to the carriages 3 and 4 in the direction of the axis A2.

[0065] The bodies 21 and 22 are oriented so as to move the milling tool, which is not shown in the accompanying Figures, within a work volume based on the specific machining needs.

[0066] FIG. 7 shows a variant in which the slide 5 has a tapered section, instead of a substantially rectangular one; therefore, the two rails 14 and the two rails 15 on the opposite sides of the slide 5 are not coplanar to one another, but are staggered in a direction parallel to the axis A1. The carriages 3, 4 are shaped in a corresponding manner, on their side facing the slide 5, and the sliders 16 of each carriage 3, 4 are arranged on planes which, in turn, are staggered in order to cooperate with the corresponding rails 14 or 15.

[0067] Finally, the invention can evidently be subjected to further variants to the embodiments described herein, though without going beyond the scope of protection set forth in the appended claims.

[0068] For example, the motors controlling the movement of the carriages 3, 4 along the axis A1 and the sliding of the slide 5 along the axis A2 could be hydraulic or pneumatic motors.