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Field of the invention

The present invention relates to a radial forging machine and to one or more forging tools.

Background art

The operating principle in the case of multiple tool radial forging is that of simultaneously processing the input metal product, by means of several tools, for example four, which act radially with respect to the longitudinal axis of introduction of the metal product to be forged.

Only manual solutions currently exist for loading and unloading the tools, that is for positioning and picking the tools onto/from the radial forging machine. Such manual solutions provide using a tool supporting equipment moved with manipulators normally employed in the forging process, i.e. by means of the aid of lifting devices.

In certain cases, such supporting equipment also allows centering the tools with respect to the machine references. Once the positioning of the support equipment is carried out in the loading procedure, the operators manually block the tools on the forging devices by using irreversible mechanical restraints. The supporting equipment is then removed.

The unloading procedure occurs in reverse by inserting the supporting equipment in the machine, manually releasing the tools from the forging devices and restraining the tools to said support equipment.

Normally, the mechanical restraint between forging device and tool is by manual blocking carried out by means of tie rods, which have to be tightened or loosened manually at each replacement. In document SU708590A1 for example, a tie rod creates a two-sided restraint between tool and head of the forging device or cylinder, or simply hammer, by means of the aid of two shaped plates working in opposition: this is the most common solution among manufacturers.

The manual procedure for replacing tools has a substantial drawback in terms of productivity of the radial forging machine: replacement times are rather significant (typically one work shift), at least one order of magnitude longer, when compared to the average duration of a forging cycle, for more recent machines.

One of the aspects most affecting the replacement time of the tools is the temperature of the tools to be manipulated in the unloading step, which is initially incompatible with the safety and health of the operators: this requires postponing the start of the unloading cycle, which cannot overlap other steps in the same cycle.

Likewise, the loading cycle requires the introduction of tools at ambient temperature. This involves the transitionary heating of the tools in the first processing, which negatively affects the homogeneity of the production lots.

Reducing machine tooling times is a key aspect for the competitiveness of a plant in situations in which productivity is a significant component, such as for radial forging machines.

A solution is disclosed in document DE102008023668A1 , in which the changing of the tools occurs by means of a radial expansion or retraction of grippers for which the tools themselves, stressed by the grippers, act in radial direction on the mechanical restraint means to allow the loading or unloading of the tools.

Thus, there is a need for obtaining an innovative radial forging machine which is capable of overcoming the aforesaid drawbacks.

Summary of the invention

It is the main object of the present invention to provide a radial forging machine, for example with two, three or four forging devices, provided with a loading/unloading system of the tools such as to avoid the use of operators on board the machine, being able of replacing the forging tools in completely automatic manner or possibly in semi-automatic manner.

It is a further object of the present invention to provide the possibility of changing tools without having to wait for the tools to cool down in the unloading step.

It is a further object of the present invention to provide a loading system which allows simple and fast tool setting, thus in the same way ensuring the possibility of preheating in a time masked by the production cycle, in order to ensure increased uniformity of the lots. Indeed, the transitionary heating of the tools is avoided in the first processings, which negatively affects the homogeneity of the production lots.

Thus, the present invention proposes to achieve the objects discussed above by making a radial forging machine which, in accordance with claim 1 , comprises:

- one or more forging devices arranged radially about a first longitudinal axis Z of feeding of the product to be forged, a respective tool being mountable on each of said forging devices,

- an automatic tool loading/unloading system for loading/unloading said tools onto/from said forging devices,

wherein said loading/unloading system comprises:

- two-sided restraining means for restraining each forging device to the respective tool,

- tool moving means adapted to translate along said first axis Z from a first position outside the forging devices to a second position at least partly inside a space delimited by the forging devices, and vice versa,

- actuation means, integrated on said tool moving means and adapted to act along the first axis Z on said two-sided restraining means, for releasing the tool from the respective forging device in an unloading step, and for blocking the tool to the respective forging device in a loading step.

Advantageously, said tool moving means comprise a support frame provided with housings; the frame being adapted to receive simultaneously, in an unloading step of the tools from the forging devices, the tools in the respective housings in the transition from said first position to said second position, and to restrain them to the support frame itself; and the frame being adapted to bring simultaneously, during the loading step of the tools onto the forging devices, the tools to the respective forging devices in the transition from said first position to said second position,

whereby, in unloading step, once the tools are restrained to the support frame, the actuation means can release the tools from the respective forging device and the tool moving means can translate from said second position to said first position, thus moving the tools away from the respective forging devices,

and whereby, in loading step, once the tools are brought to the respective forging devices, the actuation means can block the tools to the respective forging device and the tool moving means can translate from said second position to said first position, thus releasing the tools from the support frame. A second aspect of the invention relates to a method for unloading the tools from the aforesaid radial forging machine which, according to claim 20, comprises the following steps:

- providing tools blocked to respective forging devices,

- translating the moving means along the first axis Z from a first position outside the forging devices to a second position at least partly inside a space delimited by said forging devices, so that the tools are received simultaneously in the respective housings of the moving means and are restrained to the support frame of said moving means,

- actuating the actuation means along the first axis Z to act on the two-sided restraining means so as to release the tool from the respective forging device,

- translating the moving means from said second position to said first position, thus moving the tools away from the respective forging devices.

A further aspect of the invention relates to a method for loading the tools onto the aforesaid radial forging machine which, according to claim 21 , comprises the following steps:

- providing the moving means in a first position outside the forging devices, with tools arranged in respective housings of the support frame of said moving means and restrained to said support frame,

- translating the moving means along the first axis Z from said first position to a second position at least partly inside a space delimited by said forging devices, so that the tools are at the respective forging devices,

- actuating the actuation means along the first axis Z to act on the two-sided restraining means so as to block the tool to the respective forging device,

- translating the moving means from said second position to said first position, thus releasing the tools from the support frame.

The two-sided restraining means between forging device and tool allow blocking and releasing the latter by means of actuation means of any type.

The two-sided restraining means comprise one-sided prismatic restraints, in shape of reaction plates, acting between the tool and the interface element of the forging device, that is the toolholder, and releasable by means of a motion of moving away the reaction plate in direction orthogonal to the direction of motion of the forging device. Such one-sided prismatic restraints are made two-sided by the application, between said interface element and the reaction plate making the prismatic restraint, of one or more tie rods kept tensioned by elastic return means of any type.

The two-sided restraint is released by means of the application of external reaction forces which oppose the return forces of the elastic means and allow the disengagement of the tool from the forging device: such external forces are directed in opposite direction to each other.

Advantageously, the actuation means can be actuated by a classic forging manipulator, and together with the tool moving means, they allow the loading and unloading operations in automatic or possibly semi-automatic manner.

The tool moving means provide to support and move the tools, in number equal to that required by the radial forging machine, and in a preferred variant also provide to actuate the blocking and releasing system of the tools from the forging devices, the aforesaid actuation means being integrated in the moving means.

The moving function is carried out by a movable support frame to which the tools are completely restrained: the radial and circumferential blocking of the tools is such as to be obtained by means of simple translating movements of the support frame relatively to the radial forging machine. Alternatively, in completely equivalent manner, such radial and circumferential blocking can be obtained by means of the translating movement of the forging devices with respect to said support frame.

The axial blocking of the tools to the support frame exploits the aforesaid relative logic of movement equally for the coupling and the uncoupling, and is obtained by a restraint, preferably a programmed yield restraint. Such a programmed yield is based on a preassigned value of the force of separation, which can be calibrated by means of preloading elastic reaction elements.

In a preferred variant, the radial and circumferential blocking of the tools to the moving means is obtained by means of shaped profiles applied to the support frame. The longitudinal development of these shaped profiles is orthogonal to the plane containing the axes of motion of the forging devices: this allows the application and the disengagement of such restraints by means of the relative movement of the support frame with respect to the radial forging machine in the direction of the longitudinal development of the profiles.

A further aspect of the present invention provides for the system controlling the release of the two-sided restraint to be such as to allow the application of the reaction forces by acting on a single side, i.e. according to only one of the two directions of the reaction forces, by using a motion reversal device.

Said motion reversal device can be positioned on board the equipment for moving the tools or on the end part of the toolholder.

In a preferred variant, the motion reversal device is an integral part of the moving means, being formed by mechanisms in which at least one pinon meshes simultaneously on two racks arranged so that the meshing arc of each rack can be positioned on the arc of the other rack by means of a rigid 180° rotation with respect to the axis of rotation of said pinon. There are provided two reaction frames, free to rotate about a same axis, with two racks rigidly restrained to each of said two reaction frames: the pinon rotates freely about a pin restrained to the support frame, which restrains the two reaction frames to each other in rotation. Said support frame is formed by two parts free to rotate with respect to one another and rigidly restrained to each other according to the axis of rotation Z, such an axis being coincident with the one of the two reaction frames.

A first part of the support frame forms the support structure of the tools, while a second part of the support frame rotates rigidly together with the two reaction frames.

In a preferred variant, the method for loading and unloading the tools onto the radial forging machine is completely automated and is executed by activating only the known manipulators of a forging machine. Such a method comprises the following steps:

a) inserting the tool moving means into the radial forging devices;

b) rotating the two reaction frames to position the respective radial arms at the opening controls (thrust plates) of the two-sided restraining means (reaction plates) on the toolholder;

c) opening the reaction plates;

d) retracting the forging devices, in the case of unloading tools, or nearing the forging devices, in the case of loading tools;

e) closing the reaction plates;

f) rotating the two reaction frames to position the respective radial arms at an extraction position of the moving means;

g) extracting the moving means from the radial forging machine.

Therefore, the automatic loading and unloading system of the tools for the radial forging machine, object of the present invention, in particular has the following advantages:

- allowing to change forging tools in completely automatic manner, thus avoiding the presence of operators on board the machine;

- allowing to significantly reduce the times for replacing the forging tools;

- allowing an improvement of the uniformity of the production lots by allowing the possibility of preheating the forging tools to be loaded, in a time masked by the production cycle.

The dependent claims describe preferred embodiments of the invention.

Brief description of the drawings

Further features and advantages of the invention will be more apparent in light of the detailed description of a preferred, but not exclusive, embodiment of a radial forging machine, shown by way of non-limiting example, with the aid of the accompanying drawings, in which:

Fig. 1 a depicts a sectional view of first components of the machine according to the invention, in a first operating position;

Fig. 1 b depicts a top view of the first components in said first operating position; Fig. 1 c depicts a sectional view of the first components in Fig. 1 a, in a second operating position;

Fig. 1 d depicts a top view of the first components in said second operating position;

Fig. 2 depicts a complete, partly sectional view, of second components of the machine according to the invention;

Fig. 2a depicts an axonometric view of some of the second components in Fig. 2; Fig. 3 depicts a view along an axis Z of one of said second components in Fig. 2; Fig. 3a depicts a side view of a tool of the machine according to the invention; Fig. 4a depicts a side view of a further component of the machine according to the invention;

Fig. 4b depicts a top, partly sectional view of said further component in Fig. 4a; Fig. 4c depicts a perspective view of a first step of blocking a tool by means of the further component in Fig. 4b;

Fig. 4d depicts a perspective view of a second step of blocking a tool by means of the further component in Fig. 4b;

Fig. 5 depicts a perspective view of the main components according to the present invention, in a first operating position;

Fig. 6a depicts a perspective view of the main components according to the present invention, in a second operating position;

Fig. 6b depicts a perspective view of the main components according to the present invention, in a third operating position.

The same reference numerals in the drawings identify the same elements or components.

Detailed description of at least one preferred embodiment of the invention

With reference to Figures from 1 to 6, it is depicted a preferred but non-limiting embodiment of parts of a radial forging machine with four forging hammers or cylinders, or more generally, with four forging devices, said parts advantageously defining a loading/unloading system of the tools which, according to the invention, is able of replacing the forging tools in completely automatic manner or possibly in semi-automatic manner.

The radial forging machine object of the present invention comprises:

- at least two forging devices arranged radially about a first longitudinal axis Z of feeding of the product to be forged,

- at least two tools 5, each mounted on a respective forging device, preferably on a toolholder 1 of the forging device,

- an automatic tool loading/unloading system for automatically loading/unloading the tools 5 onto/from said forging devices.

The example in Figures 5, 6a and 6b shows part of a radial forging machine with four tools 5 (one of which not visible), each mounted on a respective toolholder 1 . A toolholder or interface element 1 is arranged between each forging device and the respective tool 5, once mounted on the machine.

Advantageously, this loading/unloading system comprises:

- two-sided restraining means for restraining each forging device, preferably each toolholder 1 , to the respective tool 5,

- actuation means, adapted to act on the two-sided restraining means, for releasing tool 5 from the respective forging device in an unloading step, and for blocking tool 5 to the respective forging device in a loading step,

- tool moving means, adapted to translate along axis Z from a first position outside the forging devices to a second position at least partly inside a space delimited by the forging devices, and vice versa.

The tool moving means comprise a movable support frame having a longitudinal axis coincident with axis Z, adapted to receive simultaneously, in an unloading step of the tools, the tools 5 in the respective housings 5' of said support frame in the transition from said first position to said second position, and to restrain them to the support frame. Therefore, in unloading step, once the tools 5 are restrained to the support frame, the actuation means can release the tools 5 from the respective forging device, or toolholder 1 , and the tool moving means can translate from said second position to said first position, thus moving the tools away from the respective forging devices.

Said support frame is instead adapted to bring simultaneously, during loading step of the tools onto the forging devices, the tools 5 to the respective forging devices in the transition from said first position to said second position. Therefore, once the tools 5 are brought to the respective forging devices, in loading step, the actuation means can block the tools 5 to the respective forging device, or toolholder 1 , and the tool moving means can translate from said second position to said first position, thus releasing the tools 5 from the support frame.

The two-sided restraining means comprise, for each tool 5, a pair of first plates or reaction plates 2, 2' arranged at opposite ends, along an axis Y parallel to axis Z, of a respective toolholder 1 of the forging device. The two reaction plates 2, 2' of each pair are moved in the opposite direction to each other along said axis Y and make a shape restraint (prismatic restraint) between tool 5 and toolholder 1 .

For each reaction plate 2, 2', there is provided at least one tie rod 3, 3' parallel to axis Y and crossing toolholder 1 , which is restrained at a first end thereof to the respective reaction plate 2, 2' (Figures 1 a, 1 b, 1 c, 1 d) while it is configured, at a second end thereof, to react on toolholder 1 by means of at least one elastic return element 4. Said at least one tie rod 3, 3' is provided, at said second end thereof, with a second plate or thrust plate 7, 7' for allowing the application of an external reaction force so as to release tool 5 by means of the aforesaid actuation means. Therefore, the at least one tie rod 3, 3' as described above passes through toolholder 1 , that is, crosses toolholder 1 by passing from one side to the other thereof. As shown in Figures 1 a and 1 c, the longitudinal extension of the tie rods 3, 3', which are parallel to axis Y, is indeed greater than the maximum longitudinal extension of toolholder 1 along said axis Y. Accordingly, both the first end and the second end of each tie rod 3, 3', and therefore both the reaction plate 2, 2' and the corresponding thrust plate 7, 7', are always outside toolholder 1 , at two opposite sides of the latter.

In a preferred variant shown in Figures from 1 a to 1 d, there is provided a pair of tie rods 3 for the reaction plate 2 and a pair of tie rods 3' for the reaction plate 2'; and at the second end of the tie rods, there are provided a single thrust plate 7 for the pair of tie rods 3 and a single thrust plate T for the pair of tie rods 3', to allow the application of an external reaction force on said thrust plates 7, T and releasing tool 5 by means of said actuation means.

Each pair of tie rods 3, 3' is rigidly restrained to the corresponding reaction plate 2, 2'. There are provided two pairs of elastic return elements 4; each elastic return element 4 being applied to a respective tie rod 3, 3' in order to make the prismatic restraint of the reaction plates 2, 2' two-sided.

Each reaction plate 2, 2' is free to move according to axis Y which is orthogonal to axis X along which the forging device, and therefore tool 5, moves, when mounted thereon. Each reaction plate 2, 2' is profiled so as to make a shape restraint between tool 5 and toolholder 1 . For example (Figures 1 a and 1 c), the reaction plates 2, 2' have a substantially parallelepiped shape with projections 30, 30' shaped such as to be inserted into corresponding recesses 31 , 31 ' of toolholder 1 and of tool 5, respectively. Such a restraint is applied by means of a nearing motion, along axis Y, of the reaction plates 2, 2' to axis X of the tool. The elastic return elements 4 associated with the tie rods 3, 3' are preferably, but not only, made by means of springs. In other variants, the elastic return elements 4 can comprise, for example, gas springs, elastomers, or hydraulic servo-systems as well.

Advantageously, an axial guide of the tie rods 3, 3' and of the reaction plate 2, 2' can be provided along axis Y, preferably arranged on toolholder 1 . In a preferred variant, this axial guide is made by means of the reference surfaces 8', which are the outer surfaces of the casings 8 of the elastic return elements 4. A first reaction plate 2 and the thrust plate 7' restrained to the tie rods 3', which act on the second reaction plate 2' opposite to the first reaction plate 2 (Figures 1 a-1 d), rest simultaneously on such reference surfaces 8', which do not necessarily have a circular section. Each reaction plate 2, 2' indeed has two holes in which there are inserted the casings 8 of the elastic return elements 4 of the tie rods 3, 3' which act on the opposite reaction plate. Such holes define the sliding surface of the reaction plate 2, 2' on the reference surfaces 8'.

Figures 1 a and 1 b show a toolholder 1 and a tool 5 connected to one another by means of the reaction plates 2, 2'. Figures 1 c and 1 d show instead the reaction plates 2, 2' in the release position of tool 5 from toolholder 1 .

Starting from the configuration in Fig. 1 a corresponding to the two-sided restrained position between tool 5 and toolholder 1 for a single forging device, acting on the two thrust plates 7, 7', preferably simultaneously, with a force oriented according to axis Y and directed toward axis X of the tool, causes the release of the tool itself (Fig. 1 c). Releasing such a force involves restoring the configuration in Fig. 1 a due to the action of the elastic return elements 4.

In a preferred variant, the simultaneous application of said force for each of the tools 5 of the radial forging machine occurs by means of auxiliary elements advantageously positioned on the tool moving means, and which can be actuated by the manipulator (not shown) of the radial forging machine. In other variants, the means for applying said force can be positioned on board the machine or on toolholder 1 .

The application of the release force can occur by means of at least one manipulator (not shown) of the radial forging machine, as in the preferred variant of the invention, or by means of any mechanical, hydraulic or electromechanical actuation system.

In a preferred variant, the support frame of the tool moving means comprises a first part 9, which can rotate about axis Z, provided with a plurality of radial arms 9' arranged radially with respect to axis Z. Each housing 5' for a respective tool 5 is defined by the space between two consecutive radial arms 9'.

Advantageously, there are provided blocking devices 10 fixed on said first part 9 of the support frame, for restraining the tools 5, in the respective housings 5', to said first part 9. Preferably, but not necessarily, the blocking devices 10 are provided at the free ends of the radial arms 9'. The number of blocking devices 10 corresponds to the tools 5.

The accompanying figures consider, by way of example, a radial forging machine with four forging devices, and therefore four tools 5, whereby the first part 9 of the support frame has four housings 5', four radial arms 9' and four blocking devices 10 (Fig. 3), each blocking device 10 acting on two tools 5 in respective two adjacent housings 5'.

In a preferred variant (Figures 4a-4d), each blocking device 10 comprises a base body 19, defining a longitudinal axis Z' parallel to axis Z, in which there are provided shaped profiles 18 on two opposite sides facing toward respective housings 5'. Such shaped profiles 18 have a longitudinal development along axis Z' and are preferably symmetrical with respect to a plane containing axis Z' and axis Z. The shape of said shaped profiles 18 is such as to be at least partly insertable in respective first cavities 26 (Fig. 3a) provided on two adjacent tools 5, in the transition of the moving means from said first position to said second position.

Each blocking device 10 further comprises an axial restraint mechanism, preferably arranged on the base body 19. However, it is not excluded for such a mechanism to be in a different position on the first part 9 of the support frame, in relation to the manner in which it is used.

In a first variant, such an axial restraint mechanism comprises two cams 20, which are preferably symmetrical with respect to a plane containing axis Z' and axis Z, and having a lever arm 20' shaped such as to be at least partly insertable in respective second cavities 25 provided on two adjacent tools 5, in the transition of the moving means from said first position to said second position. Thereby, the actuation is carried out of the axial restraint of the tools 5 at the first part 9 of the support frame. In practice, the lever arms 20' of two cams 20, facing the same housing 5' of tool 5 and belonging to two separate blocking devices 10, are engaged in the two second cavities 25 of the same tool.

Conveniently profiled first cavities 26 and second cavities 25 are provided on tool 5 or on an interface element applied thereto.

The two cams 20 rotate about a respective pin 21 and the angular stroke thereof is limited at a first end by the base body 19 and at a second end by a mutual contact of the cams at an abutment surface 20" thereof. The pins 21 have respective axes, both contained in a plane orthogonal to axis Z'.

Advantageously, there is provided a slider 22, adapted to move along axis Z' by means of a thrust of preloading elastic means 23, and resting by means of an end 22' thereof, in the shape for example of a plate, on a surface of the two cams 20. This configuration determines a programmed yield of the aforesaid axial restraint mechanism.

The end positions between which the two cams 20 can oscillate are of static balance for the axial restraint mechanism. An outer force capable of overcoming the thrust of the preloading elastic means 23, applied simultaneously to each of the lever arms 20', allows the transition from the position corresponding to the operating situation of the free tool (Fig. 4c) to the balance position corresponding to the operating situation of the blocked tool (Fig. 4d).

In a preferred variant, the relative nearing motion between the tools 5, which are positioned on the radial forging machine, and the support frame 9, 1 1 , along the longitudinal axis Z of feeding of the product to be processed, first allows inserting the two shaped profiles 18 of each blocking device 10 into the respective cavities 26 of two adjacent tools 5 and then the successive actuation of the axial blocking restraint by means of the lever arms 20' of the cams 20 which are inserted into the respective cavities 25 of the tools. Therefore, in this variant each tool 5 is blocked by means of two lever arms 20', each lever arm 20' belonging to a respective cam 20, each cam 20 being provided on a separate blocking device 10. In the same manner, a relative distancing motion between the support frame 9, 1 1 and the tools 5 allows the disengagement of the axial blocking restraint.

In a second alternative variant (not shown), the axial restraint mechanism of each blocking device 10 comprises a single cam, in place of only the two symmetrical cams 20. The single cam rotates about a pin and the angular stroke thereof is limited at a first end by the base body 19 and at second end by an abutment on the base body 19. The pin has the axis thereof contained in a plane orthogonal to axis Z'.

In this case, slider 22 moves along axis Z', by means of a thrust of preloading elastic means 23, and resting by means of an end 22' thereof, in the shape for example of a plate, on a surface of the single cam. This configuration determines a programmed yield of the aforesaid axial restraint mechanism.

The end positions between which the single cam can oscillate are of static balance for the axial restraint mechanism. An outer force capable of overcoming the thrust of the preloading elastic means 23, applied simultaneously to the lever arm of the single cam of each blocking device 10, allows the transition from the position corresponding to the operating situation of the free tools to the balance position corresponding to the operating situation of the blocked tools.

The relative nearing motion between the tools 5, which are positioned on the radial forging machine, and the support frame 9, 1 1 along the longitudinal axis Z of feeding of the product to be processed, first allows inserting the two shaped profiles 18 of each blocking device 10 into the respective cavities 26 of two adjacent tools 5 and then the successive actuation of the axial blocking restraint by means of the lever arm of the single cams which is inserted into a respective cavity of a respective single tool. Therefore, in this variant each tool is blocked by the lever arm of a single cam. In the same manner, a relative distancing motion between the support frame 9, 1 1 and the tools 5 allows the disengagement of the axial blocking restraint.

With regard to the actuation means which act on the thrust plates 7, T of the two- sided restraining means, in an advantageous variant where the loading/unloading system of the tools is completely automatic, said actuation means are configured to simultaneously apply the external reaction force on both the thrust plates 7, T of each toolholder 1 or forging device so as to move the respective reaction plates 2, 2' and release together all tools 5 of the forging machine.

The actuation means are adapted to act exclusively along axis Z on both sides of said two-sided restraining means.

In a preferred embodiment, the actuation means are integrated on the tool moving means. In particular, said actuation means comprise two reaction frames 12, 13 arranged along axis Z, restrained to each other in rotation about said axis Z and adapted to move axially with respect to each other, simultaneously in opposite direction from one another.

The reaction frame 13 is arranged along axis Z at least partly at a first side of the support frame; while the reaction frame 12 is arranged along axis Z at a second side of the support frame, opposite to the first side.

Therefore, the reaction frame 13 and the reaction frame 12 can simultaneously apply the external reaction force on both sides of said two-sided restraining means, that is on both the second plates 7, 7' of each toolholder 1 , arranged along an axis Y parallel to axis Z, once the moving means, and therefore the support frame, are in the position at least partly inside the space delimited by the forging devices.

Advantageously, the support frame of the moving means comprises also a second part 1 1 , adjacent and restrained axially to the first part 9 but free to rotate with respect to the first part 9, about axis Z, integrally to both the reaction frames 12, 13. This second part 1 1 supports the two reaction frames 12, 13 which, as said above, can move simultaneously along axis Z in opposite direction from one another. In a preferred variant of the invention, the second part 1 1 of the support frame is provided with an appendage 1 1 ' for moving it, for example by means of grasp of grippers of a manipulator (not shown) of the forging machine or by means of other suitable actuation mean.

Advantageously, to ensure this movement of the two reaction frames in opposite direction from one another along axis Z, the second part 1 1 of the support frame is provided with a motion reversal device.

A preferred variant of said motion reversal device is shown in the sectional part in Fig. 2. Such a motion reversal device comprises one or more pairs of pinions 15, housed on said second part 1 1 of the support frame and having the axes of rotation parallel to each other and orthogonal to a plane passing through axis Z. Each pair of pinions 15 meshes on two racks 16, 17 which are integral to the reaction frame 12 and to the reaction frame 13, respectively.

The reaction frames 12, 13 are guided axially and supported radially by means of low friction supports housed on the first part 9 and on the second part 1 1 of the support frame of the tools 5.

Prismatic restraints of any type make the two reaction frames 12, 13 and the second part 1 1 itself of the support frame integral to the rotation. For example, the end of the reaction frame 13, proximal to the second part 1 1 of the support frame, is provided with at least two projections 14 inserted into corresponding slots 14' of the second part 1 1 , or vice versa. Preferably (Figure 2a), there are provided two projections 14 which are diametrically opposite to each other, each projection 14 being provided between the two racks 17, they also being diametrically opposite to each other. Accordingly, the two slots 14' are diametrically opposite and are each provided between the two pairs of pinions 15, which are also diametrically opposite to each other.

Similarly, the end of the second part 1 1 , opposite to the end comprising appendage 1 1 ', is provided with at least two projections 24 inserted into corresponding recesses 24' provided on the inner surface of the reaction frame 12, or vice versa. In the example in Figure 2a, there are provided four projections 24 and four corresponding recesses 24'.

By applying a force directed according to axis Z to one only of the two reaction frames, an equal movement of the other reaction frame is obtained by means of the aforesaid motion reversal device, in opposite direction to the one of the reaction frame moved.

For example, by applying a force directed along axis Z on the reaction frame 12, the motion is transmitted by means of an appendage 12", from the racks 16, which are integral to the reaction frame 12, to the pinions 15, and from the pinions 15 to the racks 17, which are integral to the reaction frame 13. Therefore, an equal movement is obtained of the reaction frame 13 in direction opposite to the one of the reaction frame 12. An advantageous configuration, shown in Figures 2, 2a, 5, 6a e 6b, provides for both the reaction frames 12, 13 to be provided with respective radial arms 32, 33, in number equal to the number of tools 5, configured to push with an end thereof on both sides of the two-sided restraining means, that is on the respective second plates 7, 7'.

The radial arms 32 are arranged and move mirroring the radial arms 33. At the ends of the radial arms 32, 33, appendages 12' 13' are preferably provided facing toward the first part 9 of the support frame, which when the reaction frames are neared to each other, act directly on the thrust plates 7, 7' to release the tools 5 in unloading step, or to keep the reaction plates 2, 2' open before the loading of the tools 5 (Fig. 1 c) in the loading step.

As shown in Fig. 5, the two reaction frames 12, 13 are initially arranged, both in loading step and in unloading step, with the radial arms 32, 33 aligned at the corresponding passage compartments between the toolholders 1 of the forging devices (in loading step), or between the tools 5 fixed to the toolholders 1 (in unloading step). Starting from this configuration, it is possible for the support frame to transition from the first position outside the forging devices (Fig. 5) to a second position inside the space delimited by the forging devices (Fig. 6a), and vice versa. In said second position, the radial arms 32, 33 are outside the sides, along axis Z, of a zone occupied by the forging devices (only the toolholders 1 are shown in Figures 5 and 6a). At this point, once the reaction frames 12, 13 are rotated by such an angle that the radial arms 32, 33 are in position corresponding to the thrust plates 7, 7', a force is applied directed along axis Z, on the reaction frame 12, by means of appendage 12" thereof, and an equal movement is obtained of the reaction frame 13 in direction opposite to the one of the reaction frame 12. Thereby, all the thrust plates 7, 7' are actuated (Fig. 6b).

Therefore, it is possible to replace the tools in automatic or semi-automatic manner with the forging machine of the present invention.

With reference to the advantageous configuration shown in Figures 2, 2a, 5, 6a and 6b, the unloading of the tools occurs by means of the following steps:

1 ) providing a manipulator of the forging machine, or other suitable actuation means, grasping the appendage 1 1 ' of the second part 1 1 of the support frame; providing the moving means positioned outside the forging devices, which are in their change tool configuration, with the radial arms 32, 33 of the reaction frames 12, 13 aligned at the passage compartments between the tools 5 (Fig. 5);

2) advancing the moving means, by means of the aforesaid manipulator, in a first direction along axis Z up to the inside of the space delimited by the forging devices (Fig. 6a). This advancement ends with the insertion of the shaped profiles 18 into the respective cavities 26 of the tools 5 (Fig. 4c) and the successive actuation of the axial blocking restraint, by means of the insertion of the lever arms 20' of the cams 20 into the cavities 25 of the tools 5 (Fig. 4d);

3) moving the manipulator into a grasping position on appendage 12" of the reaction frame 12 and rotating, in a first direction about axis Z, the movable equipment, consisting of the reaction frames 12, 13 and of the second part 1 1 of the support frame so as to position the radial arms 32, 33 at the thrust plates 7, 7';

4) pushing appendage 12", by means of the manipulator, in said first direction along axis Z so as to move the reaction frames 12, 13 one toward the other, and to release the tools 5 by means of moving the reaction plates 2, 2' away from the toolholders, due to the force exerted by the radial arms 32, 33 on the thrust plates 7, 7'. The blocking devices 10 on part 9 of the support frame act as reaction restraint for the second part 1 1 of the frame on which the pinions 15 are housed of the motion reversal device, consisting of said pinions and of the racks 16, 17 which are integral with respect to the reaction frames 12, 13;

5) retracting radially, with respect to axis Z, the forging devices or cylinders along axis X, preferably up to the upper dead point thereof, to allow the disengagement of the moving means on which the tools 5 are already restrained;

6) retracting the manipulator, grasping appendage 12", in a second direction along axis Z, opposite to the first direction, to restore the resting configuration of the two- sided restraining means, that is to close the reaction plates 2, 2' on the toolholders 1 ;

7) rotating, in a second direction about axis Z, opposite to the first direction, the aforesaid movable equipment so as to position the radial arms 32, 33 aligned again to the passage compartments between the forging devices;

8) positioning the manipulator grasping the moving means, at appendage 1 1 ', and retracting the moving means, by means of the manipulator, in a second direction along axis Z, opposite to the first direction, to extract the tools 5 from the space delimited by the forging devices.

Vice versa, the loading of the tools occurs by means of the following steps:

1 ) providing the manipulator grasping appendage 1 1 ', the moving means being provided with the tools 5 to be loaded, which are arranged in the housings 5', and are positioned outside the forging devices, which are in their change tool configuration, with the radial arms 32, 33 of the reaction frames 12, 13 aligned at the passage compartments between the forging devices;

2) advancing the moving means, by means of the aforesaid manipulator, in a first direction along axis Z up to the inside of the space delimited by the forging devices;

3) moving the manipulator into a grasping position on appendage 12" of the reaction frame 12 and rotating, in a first direction about axis Z, the movable equipment, consisting of the reaction frames 12, 13 and of the second part 1 1 of the support frame so as to position the radial arms 32, 33 at the thrust plates 7, 7';

4) pushing appendage 12", by means of the manipulator, in said first direction along axis Z so as to move the reaction frames 12, 13 one toward the other and to move the reaction plates 2, 2' away from the toolholders 1 , due to the force exerted by the radial arms 32, 33 on the thrust plates 7, 7';

5) advancing the forging devices or cylinders radially, with respect to axis Z, along axis X in change tool position, up to a contact between the toolholders 1 and the respective tools 5 to be loaded;

6) retracting the manipulator, grasping appendage 12", in a second direction along axis Z, opposite to the first direction, to block the tools 5 on the respective toolholders 1 , by closing the reaction plates 2, 2' on the toolholders 1 ;

7) rotating, in a second direction about axis Z, opposite to the first direction, the aforesaid movable equipment so as to position the radial arms 32, 33 aligned again at the passage compartments between the tools blocked at the forging devices;

8) positioning the manipulator grasping the moving means, at appendage 1 1 ', and retracting the moving means, by means of the manipulator, in a second direction along axis Z, opposite to the first direction, thus extracting them from the space delimited by the forging devices. During this retraction, there is an axial disengagement of the blocking restraints by means of the exit of the lever arms 20' of the cams 20 from the cavities 25 of the tools 5 and the successive disengagement of the shaped profiles 18 from the respective cavities 26 of the tools 5.