NC machines with improved worktable

A numerical control machine includes a bearing structure-frame suited to support various other parts, at least one lower surface, at least one table suited to hold a workpiece and mounted on the lower surface, and at least one head with an electric tool-holding spindle, wherein the lower surface is inclined.

The present invention concerns NC machines for machining pieces, and in particular it concerns NC machines provided with a table that is rotated and translated on an inclined plane.

NC machining centres are known which comprise a support or table where the piece to be machined is blocked, a head with an electric spindle on which the machining tool is mounted, head translation and rotation systems intended to allow the tool to work on all sides and all angles on the piece blocked on the worktable.

Suitable programmable electronic circuits control all the movements of the machining centres, like for example the rotation speed of the tool, the translation and/or rotation of the table on which the piece to be machined is blocked, the translation and/or rotation of the spindle.

The machining centres made up as described above are commonly called CNC machining centres, that is computerized numerical control machining centres.

The CNC machining centres used at present comprise a lower plane and the table, on which the piece to be machined is blocked, is mounted thereon.

At present said lower plane is horizontal and fixed, while the supporting table can rotate the piece for the execution of processing cycles with axial symmetry on the piece itself.

The head with tool-holding spindle can perform a plurality of movements in such a way as to machine the piece on horizontal planes, in all the radial directions, and on generically inclined and vertical planes but machining the piece from top to bottom.

On the contrary, to machine the piece from bottom to top, for example to make holes or undercuts from the bottom, the head should be lowered towards the supporting plane and the spindle and also the tool should be oriented in the direction defined by the type of machining to be performed.

Said operation cannot be carried out if the lower part of the piece must be machined, as the head cannot be lowered under a given height due to the presence of the lower supporting surface.

In this case it is necessary to remove the piece from the table and place it in a different position in order to carry out the desired type of machining.

This operation obviously requires the interruption of the processing cycle with a consequent increase of production times.

In order to overcome the drawbacks described above, a new type of NC machine has been designed and constructed, which is provided with a worktable that is rotated and translated on an inclined plane.

The main object of the present invention is to provide a NC machine that allows the workpiece to be machined in any direction, with no need to re-position the workpiece on the table.

It is another object of the present invention to provide a NC machine in which the position of the workpiece can be changed through the controlled and automatic movement of the worktable.

These and other direct and complementary objects are achieved by the new type of NC machine whose worktable is rotated and translated on an inclined plane, comprising in its main parts a bearing structure-frame that supports the various other parts, a lower surface that is inclined with respect to the horizontal plane, a slide travelling on guides mounted on said inclined lower surface, a piece-holding table mounted on said slide and a head provided with a tool-holding spindle.

Said guides on which said slide travels are substantially oriented in the direction of inclination of the lower surface, so that said slide, when travelling, varies its height, thus positioning both the piece-holding table and the piece to be machined at the desired height.

In this way, the head with the tool-holding spindle can be positioned at a lower height with respect to the workpiece, in order to allow the workpiece to be machined from bottom to top, with no need to re-position the workpiece manually as is the case with the NC machines of the known type.

Said piece-holding table, furthermore, is suited to handle the piece and in particular it is at least suited to rotate the piece on a generically vertical axis.

Said electric spindle is constituted by a spindle with jaws or couplings suited to hold and rotate a machining tool, typically a milling bit.

Said electric spindle is constrained to a head that in turn is formed by a system of moving arms suited to support said electric spindle on said structure-frame as well as to translate and rotate said electric spindle on the main axes.

The invention includes a tool crib suited to contain the tools and supply the electric spindle with the tool that is necessary from time to time, depending on the type of machining to be performed.

All of the moving members are controlled by a programmable electronic circuit, typically a computer, suited to detect the position of each member as well as to control the movement and/or rotation of each member.

The new machine comprises a bearing structure (1) comprising a chamber (2) in which the workpiece (3), schematically shown in the FIGURE, is machined.

The new machine comprises a lower surface (4), inclined with respect to the horizontal plane generically indicated as plane (X), and a head (8) provided with a tool-holding spindle (81).

On said inclined lower surface (4) there is at least one guide (5) suited to allow the sliding movement of at least one slide (6), wherein said guide (5) is oriented in the direction of inclination of the lower surface (4), preferably in the direction of maximum inclination.

A support or table (7) holding said workpiece (3) is mounted on said slide (6).

Said table (7) is translated together with said slide (6) with respect to the inclined lower surface (4) and can thus be positioned at different heights, even higher than the position of said head (8).

Said head (8) can thus orient the spindle (81) even in an inclined direction (X1) in order to machine the workpiece (3) from the bottom.

Said support or table (7) holding said workpiece (3) is at least suited to rotate the workpiece (3) around a vertical axis (Y).

These are the schematic outlines that are sufficient to the expert to implement the invention; consequently, when the invention is actually implemented variants can be produced that do not alter the substance of the innovative concept.

Therefore, with reference to the above description and the attached drawing, the following claims are expressed.