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TEXT OF THE DESCRIPTION

The present invention relates to a plant for threading metal bars, in particular bars for reinforcing concrete. The plant considered herein comprises:

- a storage unit for storing a plurality of bars to be threaded, where said bars are arranged oriented in a longitudinal direction of said unit ;

- a pre-treatment station for carrying out a pre treatment machining operation on one end of said bars;

- a threading station for carrying out a threading operation on the pre-treated ends of said bars; and

- a second storage unit for storing the threaded bars.

Known plants of the type referred to require constant presence of multiple operators for transferring the bars from one point to another of the plant (from the storage unit to the various stations, and from these to the storage unit downstream), and for controlling the machine tools of the individual stations.

In this context, the present invention regards a plant of the type referred to above that presents a greater degree of automation, to make it possible to reduce or even rule out the presence of operators during operation of the plant.

In particular, the present invention regards a plant according to Claim 1.

The claims form an integral part of the technical teaching provided herein in relation to the invention.

Further characteristics and advantages of the invention will emerge clearly from the ensuing description with reference to the annexed drawings, which are provided purely by way of non-limiting example and in which:

- Figure 1 is a lateral view of the plant described herein according to a preferred embodiment;

- Figure 2 is a top plan view of the plant of Figure 1;

- Figure 3 illustrates a further embodiment of the plant described herein;

- Figure 4 illustrates yet a further embodiment of the plant described herein;

- Figure 5 illustrates a detail of the plant of Figure 1; and

- Figure 6 illustrates a further detail of the plant of Figure 1.

In the ensuing description various specific details are illustrated aimed at enabling an in-depth understanding of the embodiments. The embodiments may be provided without one or more of the specific details, or with other methods, components, or materials, etc. In other cases, known structures, materials, or operations are not illustrated or described in detail so that various aspects of the embodiment will not be obscured.

The references used herein are provided only for convenience and hence do not define the sphere of protection or the scope of the embodiments.

With reference to Figure 1, the plant described herein, designated as a whole by the reference number 10, comprises:

- a storage unit 2 for storing a plurality of bars to be threaded, where said bars are arranged oriented in a longitudinal direction of said unit L;

- a pre-treatment station 4 for carrying out a pre-treatment machining operation on one end of the bars; - a threading station 6 for carrying out a threading operation on the pre-treated ends of the bars; and

- a second storage unit 8 for storing the threaded bars.

The threading operation may consist of any of the machining operations known in the reference sector for threading ends of metal bars, in particular bars for reinforcing concrete. Among the machining operations used today there may be cited: roller threading, threading by removal of material (with or without forging), threading via friction stir welding, etc.

The pre-treatment station 4 carries out a machining operation designed to prepare the bars in a pre-set condition before carrying out the threading operation on them.

Generally, the aforesaid pre-treatment station carries out cutting of the bars either for trimming the bars or else for cutting them to size, for example, for cutting a bar twelve or more metres long and obtaining therefrom a plurality of bars of shorter length. In the latter case, the cutting station may comprise a second movement track (not illustrated) for receiving one portion of the cut bar, this second track being aligned to the track 44 and extending on the opposite side of the cutting machine 42. This portion of the cut bar will then be brought back onto the track 44 to proceed to the next stations, once the track 44 has been freed from the other portion of bar obtained from cutting.

In general, the cutting station 4 comprises a cutting machine 42 prearranged with a cutting member selectable, for example, from: shears, a band saw, or a rotating cutting disk.

The plant 10 may moreover comprise further stations according to the requirements of the specific applications. For instance, according to the threading operation envisaged, the plant may comprise a further pre-treatment station, upstream of the threading station.

In the example illustrated, the plant 10 comprises a forging station 12, set between the pre-treatment station 4 and the threading station 6, which carries out on the ends of the bars a cold machining operation with which their section is widened under an action of compression. In this way, in the threading station it is possible to obtain threaded ends that have an internal diameter that is the same as the original diameter of the bars - and not a smaller diameter.

The pre-treatment station 4 comprises, in general,

- a pre-treatment machine 42 designed to carry out the pre-treatment machining operation on one end of the bars; and

- a movement track 44 for moving the bar that has reached the pre-treatment station, according to a movement in the longitudinal direction of the bar, so as to deliver the end of the bar to the pre-treatment machine 42 and withdraw the bar from the pre-treatment machine after it has been pre-treated.

In a similar way, the threading station 6 comprises:

- a threading machine 62 designed to carry out a threading operation on one end of the bars; and

- a movement track 64 for moving the bar that has reached the threading station, according to a movement in the longitudinal direction of the bar, so as to deliver the end of the bar to the threading machine 62 and withdraw the bar from the threading machine after it has been threaded.

A similar configuration is envisaged also for the forging station 12, which comprises a forging machine 122 and a movement track 124.

With reference to Figure 2, the storage unit 2, the movement tracks 44, 64, 124 of the various stations, and the second storage unit 8 are arranged parallel to one another. The machines of the various stations are positioned at one end of the corresponding movement tracks, all on the same side (on the left as viewed in the example illustrated).

The metal bars are received in the storage unit 2 according to an orientation whereby their longitudinal axis is parallel to the longitudinal direction L of the unit 2 itself and maintain this orientation in all the stations of the plant, as likewise within the second storage unit 8, and also during their transfer from one point to another of the plant 10.

The plant 10 comprises a conveying device 14 for moving the bars from the pre-treatment station 4 to the forging station 12 according to a movement in a direction T transverse to the direction L and to the longitudinal axes of the bars themselves. Further conveying devices 16, 18 move the bars in the same way, respectively, from the forging station 12 to the threading station 6 and from the threading station 6 to the second storage unit 8.

In preferred embodiments, as in the one illustrated, each of the conveying devices mentioned may comprise an inclined surface 102 to enable rolling of the bars by gravity from the unit or station upstream to the station or unit downstream, and a series of oscillating arms 104, which are arranged underneath the movement track of the station upstream, and may be operated for being raised above the track so as to discharge the bar present on the track onto the inclined surface 102. In preferred embodiments, as in the one illustrated, the plane 102 is defined by a plurality of beams 102', inclined downwards and oriented parallel to one another and to the direction T. The arms 104 are mounted oscillating on respective surfaces parallel to one another and orthogonal to the direction L. Preferably, the arms 104 are rotatably mounted about one and the same axis I parallel to the direction L. Figure 1 illustrates the arms 104 in the position raised above the respective movement tracks for discharge of the bars onto the respective surfaces 102 immediately adjacent thereto.

With reference to Figure 1, the storage unit 2 comprises a supporting surface P on which the bars contained in the unit 2 lie, which extends in the direction T as far as in the proximity of the movement track 44 of the pre-treatment station 4. The surface P terminates on an inclined surface P', which sets in connection the supporting surface P with the movement track 44.

Transfer of the bars from the surface P to the track 44 may be carried out manually by an operator, exploiting the surface P' to get the bars to roll, by gravity, along the track 44. In addition, means may operatively be associated to the surface P, such as vibrating members, designed to favour disentangling of the bars and advance thereof towards the inclined surface P'.

In alternative embodiments, the plant 10 may comprise a lifting device (for example, a pincer lifting device or a magnet lifting device) for transporting the bars, individually, from the storage unit 2 to the track 44 of the pre-treatment station 4.

During operation, the bar that reaches the track 44 is fed thereby to the pre-treatment machine 42 for execution of the pre-treatment machining operation, and is subsequently brought back, by the track itself, into a position once again set at a distance from the machine 42, for subsequent movement of the bar towards the forging station 12.

As mentioned above, movement from the track 44 to the track 124 is governed via actuation of the arms 104 associated to the track 44, which lift the bar above the track 44 itself, thus getting it to roll along the inclined surface 102.

This sequence is repeated at all the stations of the plant, in a totally automated way, without any need for an operator to intervene for starting any step of the process described.

Finally, from the threading station 6 the bars are moved directly to the storage unit 8.

The plant 10 comprises a series of sensors that are positioned at various points of the plant to detect the presence and/or passage of the bars. Moreover, the plant 10 comprises a control unit configured to govern the various devices and apparatuses of the plant on the basis of the signals received from the aforesaid sensors in order to guarantee the sequence of movements and machining operations described above. The aforesaid control unit may be constituted by a plurality of separate control modules, each configured to implement respective steps or operations of the process described herein. This control unit may moreover be divided according to a hierarchical order so that one or more main control units govern one or more secondary control units.

In any case, it is possible to envisage embodiments of the plant in which one or more operations are implemented under supervision of the operator, for example providing a push-button for enabling operation.

By way of example, with reference to the threading station 6, the plant envisages a first sensor (not illustrated) designed to detect approach to the threading machine 62 by the bar that is moved by the track 64. Once a confirmation signal is received by the aforesaid sensor, the control unit activates the threading machine 62 to set it in a pre-set condition for receiving the bar. A further sensor (not illustrated) sends an acknowledgement signal to the control unit of reception of the bar by the threading machine 62. At this point, the control unit governs the machine 62 for execution of the threading operation.

The control unit may be configured to govern the movement track 64 according to at least two distinct speeds of movement, a higher one, for fast displacement of the bar towards the threading machine or away from the latter, and substantially lower one, for final positioning of the bar inside the threading machine 62. In this connection, the movement track may be either of aid to means of the threading machine that carry out final positioning of the bar, or else the track itself may by itself carry out positioning. In some embodiments, it may be advantageous to envisage two or more distinct speeds for displacement of the bar towards the threading machine or away from the latter, which are, for example, progressively decreasing, or increasing, as the bar approaches or moves away from the machine.

In preferred embodiments, as in the one illustrated (Figure 6), the movement track 64 is provided, at its end adjacent to the threading station 6, with a lead-in block 61, preferably with a conical surface or with wedges of various types, for centring the ends of the bars in a reference direction of the threading machine 62, while the bars are moved by the track itself towards the threading machine. The aforesaid lead-in block may be provided, for carrying out a similar function, also on the movement track 124 for the pre-treatment station 12. As anticipated above, after the threading operation is terminated, the threaded bar is brought back by the track 64 into a position set at a distance from the threading machine 62, and is subsequently moved towards the storage unit 8 by means of the conveying device 18. The control unit considers, at the same time, the signal for activating the oscillating arms 104 associated to the movement track of the threading station as signal for enabling activation of the oscillating arms 104 associated to the movement track of the forging station 12 upstream.

In general, it should in fact be noted that the control unit of the plant is preferably configured to provide a process control in which control of a given station or conveying device is based upon operation of the station or of the device downstream. This means, for example, that the forging station will not discharge the bar until the threading station has done likewise.

In various preferred embodiments, the movement track 64 is a track with motor-driven rollers.

Preferably, the rollers each have an outer surface provided with a concave profile for centring - in top plan view - on the track the bar received therein (see the roller 64A - in the front view - of the track 64 represented in Figure 5). Moreover, once again preferably, the aforementioned roller track may include a set of rollers positioned in the proximity of the threading machine, which can be adjusted in the vertical position.

Furthermore, once again in preferred embodiments, the movement track comprises, for each roller, a set of clutch units designed to release the roller from the driving motor to obtain an idle condition of the roller. This condition may be brought about when the bar is taken up by the threading machine in order to prevent sliding between the bar and the rollers - when the bar is manoeuvred by the threading machine - which could cause damage or fast wear of the rollers themselves.

In alternative embodiments, the movement track may comprise a simple sliding surface and a pusher or puller member designed to push or pull the bar along this surface.

It should now be noted that the characteristics described above may be reproduced identically for each of the machining stations of the plant 10.

In preferred embodiments, as in the one illustrated, the inclined surface 102 of the conveying device 18, which connects the threading station 6 to the storage unit 8, has an inclination considerably gentler than the surfaces 102 of the other devices. In particular, the inclined surface 102 of the conveying device 18 preferably has an absolutely gentle inclination in such a way that the individual bar that rolls thereon can be easily stopped by an operator in order to carry out testing thereon, such as screwing of a threaded body on the threaded end of the bar.

With reference now to the embodiment of Figure 3, the plant 10 may comprise a conveying device 22 that is set between the storage unit 2 and the pre-treatment station 4 and is designed to constitute a unit for accumulating bars. In a way in itself known, the device 22 has a ring member that identifies a top operating branch and a bottom return branch, and on which a plurality of compartments 22A are identified.

During operation, the compartments 22A that are located on the top branch can all be filled with a bar so as to saturate the entire device. Incidentally, it will be noted that the aforesaid loading operation is in itself very fast, even though it is carried out manually and may be performed, for example, during the cutting operation that the station 4 carries out on a bar previously fed therein.

Once the station 4 has terminated its operations and the machined bar has been fed to the station downstream, the device 22 is able to supply immediately to the station 4 a new bar to be treated. In this way, the cycle times regarding picking-up of the bars from the storage unit 2 are masked. In addition, the operator is thus free to move away from the storage unit and can dedicate himself, for example, to carry out testing on the bars that have already been threaded.

A conveying device similar to the one that has just been described may moreover be set between the pre-treatment station 4 and the forging station 12, between the forging station 12 and the threading station 6, as likewise between the threading station 6 and the storage unit 8.

In some applications, there may be the need to position the bar on the machine tool with a pre-set orientation with respect to the longitudinal axis of the bar, for example when the bars have particular sections or projections. For these applications, one or more of the conveying devices comprise, instead of the arms 104 and the inclined surface 102 described above, members that are mobile in the direction T, for example slides, configured to displace the bars, without changing orientation thereof about their own longitudinal axis. In preferred embodiments, the conveying devices prearranged for keeping the bars in one and the same orientation may be provided with walking-beam systems.

Finally, Figure 4 illustrates an embodiment in which the plant 10 comprises two threading lines 100A, 100B, which each have the same stations and the same devices as those described above with reference to Figures 1 and 2 and which are set symmetrically on the opposite sides of a common storage unit 2 designed to feed the bars to both of the two threading lines. In alternative embodiments, the two threading lines 100A and 100B may instead be set along opposite end regions of the storage unit 2. In this case, the storage unit 2 itself may envisage a roller track for feeding the bars to one and the other of the two threading lines. Alternatively, the storage unit may present appropriate prolongations for discharging the bars laterally onto the two threading lines. In yet further embodiments, the plant may envisage just one second threading station and a further storage unit in which the threaded bars coming from the second threading station are gathered.

In further embodiments, the plant described herein may be prearranged for carrying out the machining operations described above on both ends of one and the same bar. Preferably, for this purpose, each station of the plant may be provided with a second machine tool positioned at the opposite end of the corresponding roller track, with respect to the one in which the first machine tool is located (see Figure 1).

Of course, without prejudice to the principle of the invention, the details of construction and the embodiments may vary, even significantly, with respect to what has been illustrated herein purely by way of non-limiting example, without thereby departing from the scope of the invention, as defined by the annexed claims.