Technical Field The patent is applied preferably, but not necessarily exclusively, to the working of panels such as cupboard doors, frames etc., with axial, head- mounted milling tools in order to cut (mill) a surface according to a set path, following the thickness of the panel by means of a sensing device.

Background Art According to the current state of the art, the technique of the working of panels, as above, by means of a machine tool with a multitude of rotating vertical milling tools and with a sensor which, when in use, is regulated either manually or by a motorised drive according to the milling tool to be used, is well known.

Drawbacks The drawback of this type of operation is the extreme difficulty in aligning the sensing devices.

As a result, there is the problem that one of the tools may start cutting the piece before one of the others which leads to irregularities, not only with the start and finish points, but also with the depth of the cut.

Whatever the irregularity, the quality of the work will be compromised.

Since the cutting tools vary in sharpness, wear or positioning errors in the various conical tool-holders, the sensing devices are lowered or raised in order to adjust the error. This does not solve the problem in a rational manner, however, because if the position of the sensing devices is regulated, the position of the cutting tools and, consequently, of the tool-holders will be regulated badly.

As a result, the time required for calibration will be even more penalised.

There are also machine tools in which the tool-holders are regulated with respect to the sensing device, but in which the sensing device is mounted laterally and is not very functional, thus unreliable from a quality point of view.

Object of the Invention The object of this invention is to overcome the aforementioned limitations.

Description of the Invention The problem is solved as claimed by means of the characteristics described in the main claim.

The advantage is that it is very simple and quick to guarantee the level of all of the sensors being used, and their respective cutting tools.

According to the characteristics described in the secondary claims, the system, the mechanism and the machine tool are optimised, are more efficient, more compact and more reliable.

Description of an Application of the Invention These and other advantages, with the aid of the attached drawings, will be outlined in the following description of a typical application of the system, the particulars of which are to be considered an example and not a limitation.

Figs. 1 and 1A are schematic side views of the head assembly (GO).

Figs. 2 and 3 are schematic front views of two head assemblies (GO), in position for the set-up phase above the work bed for the respective pair of panels (P) to be worked and in operation on the panels.

Figs. 4 and 4A are two schematic front views of the aforementioned head assembly (GO).

Fig. 5 is a view of the assembly from the opposite side with respect to that shown in fig. 1A.

As claimed, the invention regards a machine tool used to work panels of wood and wood substitutes (P) by means of rotating chip-removal tools on an axis which is orthogonal to the surface of the panel to be worked (P), which has: - a series of heads (GO) with a vertical cutting tool, with each head having a support and drive means (2) connected to a tool-holder head (1) in order to rotate the cutting tool which is used to work the panel (P), together with a means for tracing the surface to be worked (3); - means for synchronised, parallel movement of the said cutting heads (GO) with respect to the panel (P) to be worked; - means for axial movement of the said tool-holder heads (1) and tracing means (3), orthogonal with respect to the panels to be worked (P); - the said tool-holder head (1) and respective support means (2-6) which may be adjusted axially with respect to the tracing means (5,7,30,3), in order to position all of them perfectly level (Z) by means of independent adjustment (4,41) during the set-up phase before starting the work cycle (Z) and also during or after the work cycle, by varying their position with respect to each other (1, 3).

Each of the said heads (GO) includes two sub-units which are positioned axially on a plate-type support and vertical guide (9), an upper tracer-holder

unit (5-7-3-30) and a lower (6,2) tool-holder unit (1) which, by means of a worm screw (4-41), means that they may be moved closer or further apart from each other with micrometric precision.

The advantages are: - the said upper sub-unit (5) may be moved vertically by means of vertical movement means (8,82,83); - the said upper sub-unit holds the said drive means with the micrometric axial worm-screw regulator (4,41) of the said lower sub-unit (6,2) to move it closer together or further away, and holds guide rods (7) which pass through the said lower sub-unit (2) and fit in to the support (30) for the said tracing means (3), located below the said lower sub-unit (2); - the said tool-holder and tool head (1) is guided and passes through the said support for the lower sensor means (3) so that: - when the said vertical movement means (8,82,83) is operated, the entire unit with the said tool-holder and tool head (1) and the said sensors (3) is moved for the work cycle.

Going further into detail, the operative unit is mounted on plate 9 with the two sub-units 5 and 6-2 on carriages 84 and 21-22 respectively.

The support for the vertical movement includes the alternative control means 8,81,82,83 which act upon the lower sub-unit 5 and on support 51 which, in turn, supports motor 4 for the micrometric regulator screw (41), all of which are guided by guide rods 7 which support plate 30 for the sensors 3 at their lower end.

The mandrill is indicated by 23, and is regulated by being raised and lowered within the guides 7.

The operating system is very simple. The first step is to use the regulation system to line up the various cutting tools and sensors of the units GO according to a reference plane (Z) indicated in fig. 2. The work cycle may

then be carried out by all the units (fig. 3).

The details of the work cycle may vary.

A further advantage, as shown in the illustrations, is that the sensor is annular and axial with respect to the said tool-holder unit.

This leads to increased precision and more efficient operations.