ITMI20010082A1 - TENONATRICE - Google Patents

Description

DESCRIPTION

In its more general aspect, the subject of the present invention is a tenoning machine for processing the ends of pieces for furniture, such as for example strips, armrests, as well as elements of chairs, armchairs, fixtures and the like.

According to a particular aspect, the present invention relates to a work center for processing the ends of pieces for furniture and the like.

In accordance with a further aspect, the subject of the present invention is a head for machining the ends of pieces for furniture and the like.

A known type of tenoning machine for processing the ends of pieces for furniture substantially comprises a head equipped with a rotating tool. Said known head has a box-like structure comprising levers connected to an actuation device. Thanks to these levers it is possible to perform the working movements of the tool according to a predetermined path. For example, it is possible to move the tool according to a circular or ellipsoidal trajectory to make tenons from the ends of the pieces. It is evident that in order to carry out the seats or mortises for coupling the aforementioned tenons, as well as other processes necessary to complete the pieces for furniture, a multiplicity of machines having respectively heads for milling, drilling and polishing are currently required.

In the particular case of the aforementioned known tenoning machines, the levers which move the tool during machining are arranged around the tool and make the head particularly bulky. This bulky head can be affixed by means of large guides, which, due to their size, are complex, cluttered and not very precise. Furthermore, due to the different equipment fixed to the support and movement structure of the tool, such as the equipment for gripping the piece, the movements of the box-like structure of the head are very limited, resulting in an equally limited working volume of the current machines. In addition to what has been mentioned above, known tenoning machines require the replacement of the tool for each different type of subsequent machining, and therefore increase the production times of the finished product.

The problem of the present invention is that of proposing a tenoning machine, a work center as well as a head for machining the ends of pieces for furniture and the like, which have structural and functional characteristics such as to overcome the aforementioned drawbacks mentioned with reference to the known art.

This problem is solved by means of a tenoning machine comprising a head supported by controlled movement means according to at least three mutually perpendicular axes and equipped with a group of at least three spindles, supported by this so that said group can rotate around an axis and at least reach with each spindle of said group of spindles a positioning position, said head being further provided with angular positioning means connected to said group of at least three spindles and suitable for rotating the spindle arranged in said positioning position around a first and a second axis orthogonal to each other and passing through the end of a tool received by the spindle itself.

Similarly, the technical problem is solved by providing a work center comprising two of the aforementioned tenoning machines arranged opposite each other.

The technical problem is also solved by providing a head to be applied to one of the aforementioned tenoning machines comprising a group of at least three mandrels, supported by this so that said group can rotate around an axis and at least reach with each mandrel of said group of mandrels a staging position, in which the spindle can be positioned angularly around a first and a second axis, which are perpendicular to each other and pass through the end of a tool received by said spindle.

To better understand the invention, a non-limiting exemplary embodiment thereof is described below, illustrated in the attached drawings, in which:

Figure 1 illustrates a perspective view of a tenoning machine according to the invention;

Figure 2 illustrates a perspective view of a detail of the head of the tenoning machine of Figure 1;

Figure 3 is a partially sectioned perspective view of the detail of Figure 2 according to the arrow I I;

Figure 4 illustrates a perspective view of a piece-gripping equipment facing a head;

figure 5 illustrates a perspective view of a work center comprising two opposite machines;

Figure 6 is a partially sectioned perspective view of the head of the tenoning machine of Figure 1;

Figures 7 and 8 show, in a partially sectioned perspective view, further embodiments of a head for a tenoning machine according to the invention;

Figure 9 illustrates, in a partially sectioned perspective view, the head of Figure 6 rotated by 180 ° around the axis B;

Figure 10 illustrates a perspective view of a further embodiment of a head for a tenoning machine according to the invention;

Figure 11 shows a top sectional view of the head of Figure 10.

With reference to the aforementioned figures, the numeral 10 generally indicates a tenoning machine for processing the ends of pieces for furniture.

Said tenoner 10 comprises a base 12, or a frame, equipped with longitudinal longitudinal members 14 supporting first parallel sliding guides 16, defining a first movement axis (X-X).

A carriage 18 is coupled by means of skids to said first sliding guides 16. The carriage 18 is operationally connected to first motor means 20 supported by the base 12. For example, a motor of the type known as brushless is keyed directly to a screw received in a ball screw nut fixed to the lower side of the carriage 18. Said motor means 20 are operatively connected to an actuation device 22 controlled in a controlled manner. For example, a position transducer with feedback with a numerically controlled device 23 operatively connected to said actuation device 22 is operatively connected to the motor means 20.

A column 24 rises vertically from the carriage 18 and has second parallel sliding guides 26 on one side, defining a second movement axis (Z-Z). The column 24 has a C-shaped cross section. The second guides 26 are fixed to the free end of the C arms. The compartment formed by the C arms houses the service members of the tenoning machine 10 and the motor means of the upper axes described below. .

A cross of slides 28 is provided operatively connected to said second sliding guides 26. Said cross of slides 28 supports a machining head, indicated as a whole with 30. The cross of slides 28 comprises crosspieces 32 equipped with pairs of shoes 34, mutually orthogonal, coupled to said second sliding guides 26 and respectively to third guides 36 of parallel sliding provided integral with a box-like or plate-like body 38 of the head 30 and defining a third movement axis (Y-Y) (Figure 3).

The cross of slides 28 is operatively connected to second and third motor means 40 and 42 supported by the column 24 and respectively by the box-shaped body 38 of the head 30. The motor means 40, 42 are for example motors of the type known as brushless keyed with accepted screws. in ball recirculating nut screws fixed to the internal side of the compartment of the C-shaped column and respectively to the lower side of the box-shaped body 38 of the head 30. Said motor means 40, 42 are operatively connected with the actuation device 22 controlled in a controlled manner. For example, the motor means 40, 42 are operatively connected to position transducers which are fed back with the numerical control device 23 operatively connected to said actuation device 22.

A weight compensation or counterweight device 44 is fixed to the column 24 and is operatively connected to the slide cross 28. For example, a pair of hydraulic or pneumatic cylinder and piston devices is fixed to the internal side of the column compartment 24 a C. Said cylinder and piston device is operatively connected to the slide cross 28 so as to counterbalance the action of the weight of the latter and of the head 30 operatively connected to it.

The head 30 comprises a fork 46 projecting from a shaft 48 received in the box-like or plate-like body 38. The shaft 48 is supported by bearings 50 on the wall of the box-like body 38 opposite the column 24, so as to rotate around a first positioning axis (B), for example coinciding with the axis of symmetry of the fork 46. Motor means 52 are operatively connected to the shaft 48 so as to adjust the angular position of the fork 46 about the axis (B). For example, a motor of the type known as brushless 54, by means of a transmission box 56 with screw and nut screw fixed to an internal wall of the box-shaped body 38 of the head 30, is connected to a pinion 58 which is connected by means of a toothed belt 60 to a pulley 62 keyed to the end of the shaft 48 received in the box-like body 38 of the head 30 (Figure 3). Said motor means 52 are operatively connected to the actuation device 22 and are fed back by means of a position transducer to the numerical control device 23. Served by the shaft 48 there is a brake unit 64 which blocks the rotation of the fork 46 once the desired angular position around the axis (B) has been reached.

The fork 46 has parallel grooves 68 internally and in proximity to the free end of the shoulders 66 suitable for slidingly accommodating cradle or sector guides 70. Said cradle guides 70 slide in the grooves 68 of the shoulders 66 so as to oscillate around a second positioning axis (A) orthogonal to the positioning axis (B) of the fork 46.

A group 72 of three spindles 72a, 72b, 72c is connected to the cradle guides 70 and is supported by these so that the group 72 can rotate around an axis (D) perpendicular to the rotation axes (C) of each spindle 72a , 72b, 72c (figure 6). In particular, it is envisaged that each spindle of the group can reach a so-called staging position, corresponding for example to the position of the spindle 72a of Figure 1 in which the rotation axis (C) of the spindle in question is oriented on the intersection point of said first (B) and said second (A) axis, defined as the center 74 of the positioning axes of the head 30.

The cradle guides 70 are operationally connected to motor means 76 fixed to a shoulder 66 of the fork 46. For example, a self-braking motor of the type known as brushless 78, by means of a transmission box 80 with screw and nut screw fixed to the outer wall of the shoulder 66 , is connected, by means of a shaft received in a bearing keyed in a through hole provided in the shoulder 66, to a pinion 82. Said pinion 82 is arranged inside the fork 46 and is connected by meshing with a rack 84 formed on one side of a cradle 70 guide. Said motor means 76 are operatively connected to the actuation device 22 and are fed back by means of a position transducer to the numerically controlled device 23.

Each spindle 72a-72c accommodates a tool 86, for example a cutter 88 for making tenons or mortises, or a drill 90, as well as a polishing pad. With particular advantage, the electrospindle accommodates the tool 86 so that the tool point or zero point as well as the end of the tool coincides with the center 74 of the positioning axes (B, A) of the head 30 (Figure 2).

The rotation of the group 72 of mandrels around the axis (D) is obtained for example by connecting the group 72 to one of the cradle guides 70 by means of a planetary reducer 152 (Figure 9). Said planetary reducer 152 allows the rotation of the unit 72 around the axis (D) of the same reducer 152. The planetary reducer 152 is driven, by means of a pulley 154 integral with its shell, by a belt 156 wound on a pinion 158 integral with the shaft of a self-braking motor 160 supported laterally by the unit 72. The motor 160 is for example of the type known as brushless and is operatively connected to the actuation device 23 and fed back to the numerically controlled device 22 with a position transducer. By rotating the unit 72 by 120 ° around the axis (D) of the planetary reducer 152, it is possible to bring the second spindle 72b and therefore a second tool into the position of use (in the center 74 of the positioning axes).

Furthermore, according to what is illustrated in Figure 11, the head 30 comprises feeding means for each of the mandrels suitable for making each mandrel rotate about its respective axis. In particular, the aforesaid feeding means comprise contact tracks 162 in the form of rings integral with the unit 72 coaxially to the rotation axis (D) of the unit 72. Correspondingly, the feeding means comprise sliding contacts 164 placed in contact with said tracks and mounted on the head 30, more particularly on one of the shoulders 66 of the fork 46.

In order to apply the aforementioned feeding means more easily, the head 30 can advantageously comprise a further fork 166 integral with the cradle guide 70 according to what is illustrated in figure 10. This embodiment provides that the shaft 48 accommodated in the box-like body 38 of the head 30 supports, in an angularly affixable manner around the axis (B), a bracket 150. The bracket 150 has at its free end a fixed guide 168 having the shape of an arc of circumference. The cradle guide 70 having the form of a clamp integral with the further fork 166 is coupled to this fixed guide. In the aforementioned embodiment the cradle guide 70 has on one side the rack 84 on which the pinion 82 engages, substantially as described for the embodiment of figure 2.

Facing the head 30 there is a piece-gripping device, indicated as a whole with 92. Said piece-gripping device 92 is movable away from and approaching the support and movement structure of the head 30. For example, the equipment 92 of gripping the workpiece is supported by a portal structure 94. Said portal structure 94 is connected by means of skids to the sliding guides 16 provided on the bed 12. For example, motor means 96 are fixed inside the bed 12 and is operationally connected to the lower side of the portal structure 94. In particular, the means for moving the portal structure 94 comprise a self-braking motor 98 of the type known as brushless, fixed to the bed 12 and operatively connected to a screw 100 housed in a recirculating ball nut screw provided fixed to the lower side of a base. 102 of the portal structure 94. Said motor 98 is operatively connected to the actuation device 22 and fed back to the numerical control device 23 by means of a position transducer.

Cantilevered fixed to the portal structure 94, a support plate 104 is provided which is arranged transversely to the base 12. Said support plate 104 has a longitudinal slot 106 in which sliding guides 108 are housed.

A carriage 110 equipped with a gripper 112 is operatively connected to the sliding guides 108. The carriage 110 is movable between a station 114 for loading the piece 116 and a station 118 for unloading the piece 116, passing through a work station, under the action of control means, indicated as a whole with 120. The carriage 110 is supported to the sliding guides 108 so as to arrange the gripper 112 partially above the upper surface 122 of the support plate 104 suitable to constitute the supporting and sliding surface of the piece 116. In particular, the gripper 112 comprises a first retractable shoulder jaw 124 hinged to the carriage 110 and a second clamping jaw 126, opposed to the first, selectively operated in opening and closing from and towards the shoulder jaw 124 by means of a pneumatically operated device. Said first jaw 124 comprises an abutment or tip element of synthetic material or rubber supported elastically to the body of the first jaw 124. A pop-up ejector 128 is provided near the end of the carriage 110 facing the station 118 for unloading the piece 116. At the work station, a seat is provided in the support plate 104 which partially interrupts the workpiece support and guide surface 122. The seat accommodates a retractable stop 127 urged to expel and return to the seat by a pneumatic device 129 which can be operated in a controlled manner.

Above the loading station 122 there is a vertical magazine 130 known per se. Said magazine 130 comprises a device for releasing the piece 116 synchronized with the to and fro movement of the gripper 112.

In correspondence with the work station arranged roughly in the middle of the support plate 104, above the support and sliding surface 122 of the workpiece 116 is provided a device for locking the workpiece fixed to an upper crosspiece 132 of the portal structure 94. For example, said locking device is constituted by a press 134 or press comprising pneumatic cylinder and piston devices, which can be operated in a controlled manner.

The means 120 for controlling the to and fro movement of the carriage 110 will be described in greater detail below. Said control means 120 comprise a connecting rod 136 and crank device 138 connected to a grooved bar 140 arranged longitudinally to the bed 12 and supported by it. freely rotating like a mechanical drive distributed along the pallet. In particular, the crank 138 is connected to a sleeve 142 with a grooved profile freely sliding along the grooved bar 140, so as to always be in contact with it, regardless of the position of the portal structure 94 with respect to the base 12. The grooved bar 140 is operated by means of an articulated quadrilateral device 144 connected to a gearmotor 146 housed inside the base 12. For example, the gearmotor comprises an asynchronous motor connected to a reduction box whose output shaft is provided with an engaged glyph crank with a connecting rod acting on a second crank operatively coupled to the splined bar. The ratio of the lengths of the levers of the articulated quadrilateral 144 is suitably chosen so as to have an oscillation of the splined bar 140 with different speeds according to the arc of angle traveled, in the manner described in greater detail below. The extreme angles of the oscillation of the slotted bar 140 correspond to the positions of the carriage 110 positioned in the loading and unloading station 114 of the workpiece 116. The asynchronous motor is driven by a drive, for example a device commonly known as an inverter, so to allow the carriage 110 to be stationed when it is arranged in correspondence with the work station for a time sufficient to complete the machining operations of the end of the piece 116.

In a particular embodiment of the invention, the articulated quadrilateral is moved thanks to a gearmotor operatively connected to a controlled drive.

In a further embodiment of the invention, two fixtures 92 for gripping the piece 116 are provided, sliding on the same bed 12 so as to be movable separately towards and away from the head 30 to support the piece 116 near its ends.

In an advantageous embodiment of the invention, two machines 10 are provided for processing the ends of pieces 116, arranged opposite each other so as to be active simultaneously on the two ends of the piece, constituting a machining center 148 (Fig. 5) . The two machines 10 are advantageously arranged sliding on the same frame or base 12. Interposed between the two machines 10 are provided two equipment 92 for gripping the piece.

The operation of the tenoning machine 10, of the machining center 148 and of the head 30 for processing the ends of pieces 116 for furniture is described below with reference to Figures 1, 4 and 5.

The piece 116 to be machined is released from the vertical magazine 130, arranging itself on the supporting and sliding surface 122 between the jaws 124, 126 of the gripper 112.

Preventively, the portal structure 94 supporting the fixture 92 for gripping the piece 116 is arranged along the bed 12 so as to align the support plate 104 with the end of the piece 16 to be machined.

Following a command given by the numerical control device 23, the gripper 112 is clamped at the end of the workpiece 116 and, by means of an oscillation of the grooved bar 140, the carriage 110 is brought into the work station, below the locking. During the last steps of approaching the gripper 112 to the work station, with a command given by the control 23 to the pneumatic device 129, the retractable stop 127 is extracted from the seat of the support plate 104. The carriage 110, thanks to a suitable actuation law given by the inverter to the gearmotor 146, after carrying out the steps of approaching the work station at high speed, slows down so as to rest the piece 116 without impact on the retractable stop 127. The stroke of the carriage continues thereafter in order to preload the abutment element of the first shoulder jaw 124 and unload the second clamping jaw 126, to allow the opening of the gripper 112 following the clamping of the piece 116. 116 with the lowering of the tamper 134 the opening of the pincer 112 and the return of the carriage 110 are commanded. 114 of workpiece load 116.

At the end of the processing, while the carriage 110 brings a second piece 116 to the working position, the ejector 128 placed at the end of the carriage 110 pushes the piece 116 now processed and freed by the action of the tamper 134 towards the unloading station 118.

With the piece 116 locked in the working position, the tenoning machine 10 is moved by acting on the axis (X-X) so as to bring the head 30 in proximity to the working area. Thanks to the fact that the tool 86 is supported at the end of a fork 46 which extends frontally from the box-like body 38 of the head 30, when the tool 86 reaches the working point or the working area the support structure and movement of the head 30 and in particular the carriage 18 and the column 24 will be considerably set back with respect to the end of the piece 116, guaranteeing ample positioning movements for the tool 86.

The unit 72 is made to rotate around the axis (D) to bring the spindle 72a and the selected tool 86 into the nesting position. The positioning of the spindle and of the tool 86 takes place by adjusting the position of the unit 72 and of the corresponding spindle 72a by means of the rotation (or yaw) of the fork 46 around the first positioning axis (B) and the oscillation (or pitching) of the cradle guides 70 around the second positioning axis (A).

Arranged the tool 86 according to the predetermined direction, thanks to the controlled movement of the three orthogonal axes (X-X, Z-Z, Y-Y) it is possible to move the slide cross 28, the box-shaped body 38 and the carriage 18 in order to move the tool 86 according to the desired route.

The machining of both ends of the workpiece 116 can take place simultaneously thanks to the provision in the work center 148 of the two opposing machines 10 operating simultaneously.

From the above it can be appreciated that one of the main advantages of the invention is given by the fact that by mounting a group with at least three spindles on the tenoning machine, it is possible to perform various processes, such as for example milling, drilling, cutting or other. Furthermore, the presence of a group 72 of spindles makes it possible to perform more than one machining with a single placement of the piece, obtaining high machining precision, greater flexibility and production speed, as it is simply necessary to rotate the group 72 to bring the chosen tool.

To the above is added the fact that the tool, supported by one of the spindles of the group, is moved directly thanks to the provision of angular positioning means around two axes (B, A) orthogonal to each other and passing through the end of the 'tool. The movements of the yaw and pitching unit make it possible to orient the tool axis (C) in an extremely precise way, which is in the parking position, with respect to the end of the piece to be machined.

In a further embodiment of the invention, the motor 54 of the axis (B) of the shaft 48 supporting the fork 46 or of the bracket 150, the motor 78 of the axis (A) of oscillation of the cradle guides 70 and the motor 160 of the axis (D) of oscillation transversal to the group 72, are continuously controlled by the numerically controlled device 23, so that they can also be used as work axes for making ends of pieces with complex spatial surfaces.

A further considerable advantage is the fact that the work movements are performed by linear axes (X-X, Z-Z, Y-Y), which, even if of considerable size, are very precise. Furthermore, having arranged the electrospindle at the end of a fork projecting onto the working area or volume, allows the head support and movement structure (the carriage 18 and the column 24) and also the body itself to be moved back considerably. 38 box-shaped head, leaving extreme freedom of movement to the tool. Consequently, with the same working volume with respect to known machines, the tenoning machine object of the invention is of much smaller dimensions and, with the same dimensions or overall dimensions compared to known machines, vice versa, with the tenoning machine object of the invention, a volume of much wider work.

Additional benefits are outlined below.

The end of the tool is not moved during the movement of the positioning axes (A) and (B), simplifying, as well as making the setting up of the tenoner quicker and more precise and therefore allowing high productivity for both large and for small production batches.

The kinematic chains for moving the axes (X-X, Z-Z and Y-Y) are of simple and precise construction (motors controlled in a controlled way and directly connected, without the interposition of any gearbox, to ball screws), allowing machining tolerances and extremely high accelerations and speeds of moving parts.

The provision of an electrospindle allows to use high revolutions of the tool, allowing very accurate finishing of the piece.

The support and movement structure of the head 30, comprising the carriage 18, the column 24 and the cross of slides 28, has a high stiffness and sturdiness, thus resulting in very precise and rapid movements, thanks also to the fact that all axes are provided. (X-X, Z-Z, Y-Y) checked.

Thanks to the structure of the support and movement means of the head and to the structure of the head itself, the tenoning machine object of the invention is extremely flexible, allowing all the machining of the ends of pieces for furniture to be carried out with a considerable variety in the shapes that can be obtained, for example milling and in particular tenoning and mortising of any shape or shape, grooves, as well as drilling and polishing.

Machining precision and flexibility are further increased thanks to the provision of the piece-gripping equipment independent of the head support and movement structure. In particular, the stresses induced by the sudden accelerations of the linear axes (X-X, Z-Z, Y-Y) are not transmitted directly to the piece gripping equipment.

The piece gripping equipment can be arranged along the bed in the most suitable position for gripping pieces of complex spatial shapes.

The provision of a gripper movement device comprising a rotating rather than an alternative actuation device, as is instead suggested by the state of the art, allows to have a considerable loading and unloading speed of the piece.

Furthermore, the provision of an articulated quadrilateral for the operation of the grooved bar allows, without interrupting the rotation of the motor, to accelerate and slow down the grippers for positioning the workpiece from the loading station to the working position and from the working position to the unloading station;

The provision of a portal structure allows the locking means of the piece to be arranged in such a way as not to hinder the machining head, increasing the working volume.

It is clear that variations and / or additions to what has been described and illustrated above may be provided.

Some possible variants of embodiment of the head 30 and in particular of the group 72 of spindles are illustrated in Figures 7 and 8. In addition to the head of Figure 2, in which the respective axes of rotation of the three spindles 72a-72c intersect at a defining point the center of the group 72 and are arranged at 120 ° from each other, further embodiments are possible in which the arrangement and / or number of the mandrels varies. For example, Figure 7 illustrates a group 72 of four spindles 72a-72d whose respective rotation axes are arranged at 90 ° from each other.

Furthermore, as illustrated in Figure 8, the unit 72 can comprise three spindles 72a-72c, in which the rotation axes of two spindles 72a 72b intersect at a point defining the center of the unit while the rotation axis of the remaining spindle 72c it is disposed tangentially to a circumference having the center of said group as its center.

Particularly the last embodiment allows to obtain considerable advantages, such as an easier approach to the piece to be machined and a more rapid positioning, especially in the machining perpendicular to the longitudinal axis of the piece. This solution allows for example to solve the problem of making grooves at the end of the piece, in particular in the case of legs intended to be coupled to the tubular support structure of chairs or other, in which it is necessary that said grooves extend over the entire width. of the piece and have a longitudinal axis perpendicular to the longitudinal axis of the piece itself. In fact, this situation is practically impracticable with machining heads as illustrated in Figures 2 and 7, because during machining the head would overlap the piece gripping equipment.

It is also possible to provide for the movement of the arc guides 70 a worm screw, connected to a motor, rotatably fixed to a shoulder 66 of the fork 46 and connected by tangential meshing with a helical toothed rack formed on one side of a guide. 70 to cradle. In this way it is possible to avoid jamming of the motor means caused by the deposit of dirt or shavings on the rack.

Furthermore, in the case of machining of pieces having significant transversal dimensions, the retractable stop, constituting the abutment of the work station, is housed in a seat provided in a shelf extending from the upper crosspiece 132 of the portal structure 94 towards the plate 104 of support.

As can be seen from Figures 6-9, the tool can be angularly affixed along a further third axis (D). The shaft received in the box-shaped body 38 of the head 30 supports the bracket 150 in an angular way around the axis (B). cradle served by actuation means 76. As previously described, the mandrel assembly 72 is connected to the cradle guide 70 by means of a planetary reducer 152 (Figure 9). Said planetary reducer 152 allows the rotation of the electrospindle 72 around the axis (D) of the same reducer 152. The planetary reducer 152 is driven, by means of a pulley 154 integral with its shell, by a belt 156 wound on an integral pinion 158 to the shaft of a self-braking motor 160 supported laterally by the spindle 72. The motor 160 is for example of the type known as brushless and is operatively connected to the actuation device 23 and fed back to the numerically controlled device 22 with a position transducer. By rotating the unit 72 around the axis (D) of the planetary reducer 152, it is possible to bring the respective spindles into the parking and use position (in the center 74 of the parking axes). In this way it is possible to perform more than one machining with a single placement of the piece, obtaining high machining precision, greater flexibility and production speed.

In a further embodiment of the invention, the motor 54 of the axis (B) of the shaft 48 supporting the fork 46 or of the bracket 150, the motor 78 of the axis (A) of oscillation of the cradle guides 70 and the motor 160 of the axis (D) of oscillation transversal to the group 72, are controlled by the numerically controlled device 23 in a continuous way, so as to be able to be used as work axes to make ends of pieces with complex spatial surfaces. For the axis (D) it is for example the case illustrated in Figure 6 in which the axis (C) of rotation of the spindle 7a being machined does not pass through the center 74 where the head 30 is located.

Claims (36)

CLAIMS 1. Tenoning machine (10) comprising a head (30) supported by controlled movement means along at least three axes (X-X, Z-Z, Y-Y) orthogonal to each other and equipped with a group (72) of at least three mandrels (72a-72c), supported by this so that said group can rotate around an axis (D) and at least reach with each mandrel (72a-72c) of said group (72) of mandrels a staging position, said head being also provided with staging means angular connected to said group (72) of at least three spindles and adapted to rotate the spindle (72a) arranged in said staging position around a first and second axis (A, B) orthogonal to each other and passing through the end (74) of a tool received by the spindle itself. 2. Tenoning machine according to claim 1, wherein the respective axes of rotation (C) of the at least three mandrels (72a-72b) of said group (72) intersect at a point defining the center of said group. 3. Tenoning machine according to claim 2, in which the respective axes of rotation (C) of the mandrels (72a-72c) of said group (72) are arranged at 120 ° from each other. 4. Tenoning machine according to claim 1, wherein the rotation axes (C) of two mandrels (72a, 72b) of said group (72) intersect at a point defining the center of said group and the rotation axis (C ) of the remaining mandrel (72c) of said group (72) is disposed tangentially to a circumference having as its center the center of said group. 5. Tenoning machine according to claim 2, wherein said assembly (72) comprises four mandrels (72a-72d) whose respective rotation axes (C) are arranged at 90 ° from each other. 6. Tenoning machine (10) according to claim 1, wherein said group (72) of at least three mandrels (72a-72c) is supported by controlled movement means. 7. Tenoning machine (10) according to one of the preceding claims, wherein the head (30) comprises a fork (46) projecting from a shaft (48) received, in an angularly affixable manner around said first axis (B), in a box-like body (38) of the head (30). 8. Tenoning machine (10) according to claim 7, in which in the box-like body (38) of the head (30) there is a gearmotor (52) connected by means of a belt (60) to a pulley (62) keyed on the shaft (48) ) of fork rotation. Tenoning machine (10) according to claim 7, wherein the fork comprises cradle guides (70) for angular positioning of said group (72) of at least three mandrels (72a-72c) around said second axis (A). Tenoning machine (10) according to claim 9, wherein the fork (46) supports a gearmotor (76) which has a pinion (82) in meshing with a rack (84) provided in one of said cradle guides (70) . 11. Tenoning machine according to one of claims 7 to 10, wherein the head (30) comprises a further fork (166) integral with said cradle guide (70) and supporting said group (72) of at least three mandrels (72a 72c). Tenoning machine (10) according to one of the preceding claims, wherein said group (72) of at least three mandrels (72a-72c) is connected to the head (30) by means of a planetary reducer (152) driven by a gearmotor and defining said axis (D). 13. Tenoning machine according to one of the preceding claims, wherein the head (30) comprises feeding means for each of said mandrels (72a-72c) adapted to rotate the mandrel around the respective axis (C). 14. Tenoning machine according to claim 13, wherein said feeding means comprise contact tracks (162) integral with said group (72) of at least three mandrels and sliding contacts (164) mounted on said head (30) and placed in contact with said tracks (162). Tenoning machine (10), according to any one of the preceding claims, characterized in that means for carrying out the machining movements of the piece (116) are placed between a frame (12) and the head (30). Tenoning machine (10) according to claim 1, in which said controlled movement means are supported by a frame (12). 17. Tenoning machine (10) according to claim 16, in which the frame (12) supports a carriage (18) sliding along longitudinal guides (16) defining said first axis (X-X) of the three orthogonal axes of controlled movement of the head (30 ). 18. Tenoning machine (10) according to claim 17, in which a column (24) is raised from the carriage (18) having vertical guides (26) defining said second axis (Z-Z) of the three orthogonal axes of controlled movement of the head (30) . 19. Tenoning machine (10), according to claim 18, in which a cross (28) of slides supporting the head (30) is movable along the column (24). 20. Tenoning machine (10), according to any one of the preceding claims, in which an equipment (92) for gripping the piece (116) facing the head (30) and moving away from and approaching from a support and handling structure is provided of the head (30). 21. Tenoning machine (10), according to claim 20, wherein the equipment (92) for gripping the workpiece (116) comprises a carriage (110) equipped with a gripper (112) and that the carriage (110) is movable in a slot (106) formed in a support plate (104) between a workpiece loading station (114) and a workpiece unloading station (118), passing through a work station, under the action of means ( 120) of command. 22. Tenoning machine (10), according to claim 21, wherein a retractable shoulder jaw (124) is hinged to the carriage (110) opposed to a clamping jaw (126) selectively controlled in opening and closing from and towards the shoulder jaw (124), constituting said gripper (112). 23. Tenoning machine (10), according to claim 21, in which a pop-up ejector (128) is provided near the end of the carriage (110) facing the workpiece unloading station (118). 24. Tenoning machine (10), according to claim 21, wherein said control means (120) comprise a connecting rod (136) and crank (138) device connected to a grooved bar (140). 25. Tenoning machine (10), according to claim 24, characterized in that it comprises an articulated quadrilateral device (144) for operating the grooved bar (140). 26. Tenoning machine (10), according to claim 21, in which a vertical magazine (130) for the pieces (116) to be machined is provided above the loading station (114) of the carriage (110) equipped with the gripper (112). 27. Tenoning machine (10), according to any one of claims 20 to 26, wherein the fixture (92) for gripping the workpiece (116) is supported by a portal structure (94). 28. Tenoning machine (10), according to claim 27, in which the portal structure (94) has a device for locking the piece (116) in process. 29. Tenoning machine (10), according to claim 28, in which a presser (134) is provided above the supporting plate (104). 30. Tenoning machine (10), according to claim 21, in which a retractable stop (127) is provided in the support plate (104) at the work station. 31. Tenoning machine (10), according to claim 1, in which the controlled movement means comprise motors (20, 40, 42) controlled in a controlled manner and connected to ball screws adapted to move the parts of the support structure and movement of the head (30). 32. Tenoning machine (10) comprising two fixtures (92) for gripping the piece (116) as per claim 20, movable separately towards and away from the head (30) to support the piece (116) at the ends. 33. Machining center (148) comprising two tenoning machines (10), as claimed in any one of the preceding claims, arranged opposite each other. 34. Machining center (148), according to claim 33, in which the two opposite machines (10) are simultaneously active on the two ends of the piece (116). 35. Machining center (148), according to claim 33, in which the two opposite machines (10) are supported by the same frame (12). 36. Head (30) for a tenoning machine according to one of claims 1 to 32, comprising a group of at least three mandrels, supported by this so that said group can rotate around an axis (D) and at least reach with each mandrel said group of spindles a positioning position, in which the spindle can be positioned angularly around a first (B) and a second (A) axis, mutually perpendicular and passing through the end (74) of a tool (86) received from said spindle.