The apparatus considered herein is well known in the technical field of the processing of tubes or other products of the iron and steel industry such as bars, rods and the like, as will become clearer from the continuation of this description; apparatus of this type is used for introducing the semi-finished products into machines in which they are acted on by working rollers which impart to them a combined movement: that is, a forward movement along a working line or axis, and a rotary movement about this axis.

Examples of machines of this type are so-called tube-straighteners or helical rolling machines, also known as cross- or oblique-rolling machines.

Essentially, in tube-straightening machines or, more briefly, tube-straighteners, the final dimensional tolerances are conferred on a semi- finished tube by the action thereon of working rollers which, for this purpose, have a particular oblique or inclined arrangement to the working axis; in fact, by virtue of this particular arrangement, the tube is rotated and translated relative to its own longitudinal axis and is simultaneously deformed by rollers with which it gradually comes into contact so as to adopt its final shape; for further information on the subject of processing machines such as tube-straighteners or oblique-rolling machines, etc., in which tubes or rod-shaped bodies in general are processed in the particular conditions described only briefly herein, reference should be made to the manuals and technical literature relating to the subject.

In the light of what has been stated so far, in the description and in the following claims, in which, for brevity, reference will be made solely to tubes and/or to machines for straightening them, the arguments set out are nevertheless intended also to apply to rod-shaped or elongate bodies in general and to machines for processing them.

An important technological aspect relating to these machines is connected with the introduction of the tubes or bodies into the machines; in fact, owing to the particular combined translational and rotational movement imparted by the working rollers, the conditions in which introduction takes place assume considerable importance for preventing heavy stresses on the products to be processed or impacts thereof against the surfaces of the rollers disposed at the input of the machine.

Currently, in order to prevent the problems set out above, it is known to use input stations disposed upstream of tube-straightening machines and constituted essentially by a pair of rollers disposed on opposite sides of the line of advance of the tubes and having axes arranged obliquely like those of the tube straightener itself; these stations therefore initiate the rotational/ translational movement of a tube to be processed which, when it reaches the input of the straightening machine, is already in a condition such as to favour the movement which will be imparted to it by the working rollers. These stations are also known to experts in the art by the term "pinch rolls" . A considerable disadvantage of pinch rolls is that it is not usually possible to adjust the angle of inclination of the rollers to the line of advance of the tubes; the adverse effects connected with this detail will be understood better from the following.

In short, it can be considered that the only effective adjustment of which these input stations are capable consists of an ability to vary the speed of the rollers which are driven by electric or hydraulic motors of known type.

As an alternative to this solution, normal tracks with driven rollers having axes inclined to the line of advance of the tubes are also used for introducing tubes into straightening machines. In this case also, the only possible adjustment is that of the speed of rotation of the rollers, the angle of inclination of which to the line of advance of the tubes is not adjustable, and the variation of the rotational/translational movement imparted by the rollers to a tube to be introduced is not always effective since the tube is not "gripped" well as it is by the opposed rollers of the pinch rolls but is advanced simply bearing on the roller track.

In other words, it can be said that, in the prior art, apparatus for introducing tubes or rod- shaped bodies in general are not flexible from a functional point of view and cannot satisfactorily adapt the two components of the speed which they have to transmit, that is, the translational component and the rotational component of the rotational/translational movement imparted to the tubes or bodies for the processing thereof, in dependence on the various conditions required by production.

The object of the present invention is therefore to remedy this situation by providing apparatus for introducing the aforementioned tubes or other bodies which has structural and functional characteristics such as to overcome the limitations encountered in the prior art examined above.

This object is achieved by apparatus the characteristics of which are set out in the claims appended to this description.

For a better understanding of the invention as a whole with its characteristics and the advantages resulting therefrom, a preferred but not exclusive embodiment thereof is described below and illustrated in the appended drawings, in which: Figure 1 is a perspective view of apparatus for introducing tubes according to the present invention, associated with a tube-straightening machine, Figure 2 is a plan view of the apparatus of Figure 1, Figures 3 and 4 are respective transverse sections of the apparatus of Figure 1.

In the drawings, apparatus for introducing tubes according to the invention is generally indicated 1, and is situated upstream of a tube- straightening machine shown only partially in Figures 1 and 2; the apparatus 1 is composed of two portions arranged in series on a reference axis L along which the tubes to be introduced are advanced; the first portion consists of a tube-guide channel 2 from which the second portion, that is, a tube- feed device 3, extends.

In the drawings, the axis L coincides with the axis of a tube T loaded on the apparatus; it is appropriate to point out, however, that the level of the axes of the tubes relative to the fixed parts of the apparatus may vary according to the various diameters of tubes to be introduced at any particular time; this does not, however, have any bearing with regard to an understanding of the description of the invention given herein.

The guide channel 2 consists of a series of sections 2a which are aligned a short distance apart along an axis of advance L of the tubes and between which pivoting rockers 4 are interposed; the rockers are substantially "C"-shaped and are intended to load the tubes into the channel 2, as will be explained further below. Beside the guide channel 2 there is also an inclined plane 7 along which the tubes are rolled when they are loaded.

The rockers 4 are operated simultaneously by means of a shaft 5 arranged parallel to the channel 2 in order to pivot between a first operative position in which they extend towards the top of the channel so as to be able to receive a tube T sideways relative to the apparatus 1 (see the broken outline in Figure 3) and a second operative position in which the rockers face the bottom of the aforesaid channel 2.

The feed device 3, which is disposed downstream of the guide channel 2 and upstream of the straightening machine along the axis L in the direction of advance of the tubes indicated by the arrow in the drawings, has a set of three rollers 10, 11 and 12 offset along the axis L already mentioned and having respective axes of rotation parallel thereto; essentially, the rollers 10, 11 and 12 are mounted so that their attitude is variable, as will be explained in greater detail below, on a slide 13 slidable to and fro along the axis L.

In particular, the attitude of the roller 12 is varied as a result of the pivoting of an arm 14 articulated to the slide 13 and operated by a hydraulic actuator 15 of known type; the arm 14 can pivot from a first operative position removed from the line of advance of a tube T to be introduced and from the rollers 10 and 11 to a second operative position in which the roller 12 comes into contact with the aforesaid tube T.

The rollers 10 and 11, on the other hand, are mounted for rotating on a movable support 16 constituted essentially by a platform which can be raised and lowered by a hydraulic arm 17 with a vertical axis; the hydraulic arm and the movable support are fitted on the slide 13. Like the above- mentioned arm 14, the support 16 is also movable between a first operative position removed from the line L of advance of a tube and a second operative position closer to this line.

The roller 12 is driven by an electric or hydraulic motor, not shown in the drawings, in an adjustable and known manner which allows it to be rotated at a continuously variable speed, whilst the rollers 10 and 11 are idle. The speed of translation of the slide 13 is also adjustable in accordance with an operating characteristic variable continuously with time, for the reasons which will be explained further below; in this connection, it is necessary only to add that, in the embodiment considered herein, the slide 13 is controlled by a hydraulic thrust element 18 visible in Figure 1.

The apparatus described operates as follows.

The tube T to be processed is loaded by being rolled along the inclined plane 7 onto the rockers 4 when they are facing towards the top of the channel 2 in their first operative condition described above; the rockers are then pivoted to bring them to the second operative position as a result of which they deposit the tube T loaded on them in the guide channel 2 and are positioned so as not to interfere therewith, as shown in Figure 3.

At this stage of the operation of the apparatus, the pivoting arm 14 of the feed device 3 is in the position removed from the rollers 10 and 11 thus allowing the tube to be loaded by the rockers 4 with the head end of the tube bearing on the rollers 10 and 11 (see Figure 1); for this purpose, the movable support 16 is disposed in its position closer to the line of advance of the tube; that is, it is raised by the hydraulic arm 17 to a position such as to bring the upper portions of the rollers 10 and 11 to substantially the same level as the bottom of the guide channel 2, as shown in Figure 4.

After the tube had been loaded, the arm 14 pivots to its second operative position thus bringing the roller 12 into contact with the tube T which has just been loaded and, at the same time, the roller 12 is rotated by its motor.

It should be noted that, at this stage of the loading of the tube, the slide 13 is in the vicinity of the output end of the guide channel 2, that is, it is spaced from the tube-straightening machine, adjacent the apparatus of the invention.

From the operating condition just described, the slide 13 and the tube extending between the rollers 10, 11 and 12 translate together towards the input of-the tube-straightening machine so that the tube T which, in these circumstances, is supported by the guide channel 2 and by the feed device 3, adopts a rotational and translation movement resulting from the forward movement of the rollers 10, 11 and 12 together with the slide 13, in combination with the rotation imparted to it by the driven roller 12.

The tube can thus be introduced into the straightening machine in an optimal manner; it is necessary only to indicate that, at this stage, as soon as the rollers of the tube-straightener have gripped the tube introduced into it, the rollers 10, 11 and 12 of the device 3 are simultaneously moved away from the tube which, at this stage, is therefore supported solely by the guide channel 12.

The apparatus of the invention in fact achieves optimal synchronism between the rotational/ translational movement of a tube loaded thereon and the conditions of movement with which the tube is subsequently processed in the straightening machine; relative movements between the tube to be introduced and the working rollers of the tube-straightening machine are thus eliminated at the input stage, achieving considerable advantages amongst which are: the elimination or reduction of damage to the end portions of the tubes to be introduced, a reduction of wear of the working rollers of tube-straightening machines where the first contacts with the tubes introduced normally take place, and a reduction in the probability of stoppage or slippage of a tube during its introduction into the processing machine.

It can easily be understood that, to achieve these considerable advantages, it suffices to adjust the speed of rotation of the roller 12 as well as the speed of advance of the slide 13, thus varying at will the rotational/translational components of the movement imparted to the tube loaded on the apparatus of the invention and synchronizing this movement with any operative condition of the tube- straightening machine into which the tube T is to be introduced.

This is because, in the apparatus according to the invention, the speed of rotation of the roller 12 of the device 3 serves to control that of the tube to be introduced, whilst the speed of translation of the slide 13 imparts a similar axial movement to the aforesaid tube.

In other words, in the apparatus of the invention, the rotational/translational movement imparted to a tube to be introduced is not achieved by the inclination of the axes of rotation of the rollers to the axis of advance of a tube, but by their combined rotational and translational movement Since the speed of rotation of the driven roller 12, like the speed of translation of the slide 13 on which the rollers 10, 11 and 12, are mounted can be adjusted continuously, for example, with the use of electric or hydraulic motors with speed characteristics variable linearly with time and/or with the use of suitable mechanisms for the reduction and conversion of the drive, it is clear from the foregoing that the apparatus according to the present invention achieves the object set at the beginning.

That is, by virtue of the pivoting arm 14 and the hydraulic arm 17, the apparatus of the invention can be adapted very quickly and easily to various working diameters; it should, however, be pointed out, in particular, that the rotational/ translational movement of a tube to be introduced into a downstream processing machine is controlled entirely by virtue of the fact that the speed components imparted thereto, that is, the rotational and translational components, can be varied independently of one another. In this connection, it should be noted that, in the apparatus of the prior art, since the angulation of the axes of rotation of the rollers could not be adjusted relative to the direction of advance of a tube, the only adjustment which could be carried out was that relating to the variation of the speed of rotation of the rollers; this meant that, in the known apparatus, the pitch of the helical path followed by any point of a tube during its rotational/ translational movement could not be varied since it was not possible to adjust the aforesaid angulation of the rollers on which the size of the pitch depends.

In the apparatus of the invention, on the other hand, since the methods of transmitting the rotation and the translation to a tube to be processed are separate (because they do not depend on the inclinations of the rollers), it is possible to have complete control over the pitch of the aforementioned helical path, thus enabling the tube to be introduced into the downstream processing machine in accordance with any operative condition thereof.

It should also be pointed out that, in the apparatus of the invention, a tube is "gripped" by the rollers 10, 11, and 12, that is, they exert a gripping action on the tube which further favours the control of its movement, as mentioned above with regard to pinch rollers and in contrast with roller tracks.

It should also be stressed that all of the technical objects set out above are achieved by apparatus which can be produced in a structurally and functionally simple manner and thus at low cost.

The feed device 3 in fact presents no particular difficulties of design and mechanical construction since it can be produced with conventional components (motors, hydraulic cylinders, speed variators, etc.).

Naturally, variants of the invention with respect to the embodiment described above should not be excluded.

By way of indication, it is pointed out that the offset arrangement of the rollers 10, 11 and 12, as well as the positioning of the rollers 10 and 11 with a distance less than their diameters between their axes of rotation (see Figure 4), are in fact particularly suitable for tubes or rod-shaped bodies having small diameters; naturally, however, the aforesaid rollers could be mounted side by side and/or with an interaxial spacing greater than their diameters. It is then only necessary to explain that the feed device 3 may have more, or even possibly less, than three rollers (the possibility of using only two rollers in some cases should in fact not be excluded); it is also clear that it is not strictly necessary for all of the rollers to be mounted on a pivoting arm or on a movable support so as to be movable away from or towards the others but, more generally, there are various possible configurations in which one or more rollers are provided with this capability for variation of their attitude between a position in the vicinity of a reference axis or line and a removed position, whereas the others, on the other hand, are fixed.

It need hardly be pointed out that many different means and not only the type constituted by a pivoting or hydraulic arm as described in the foregoing example may be used for achieving this variable attitude.

Moreover, it is quite clear that the number of driven rollers is a question of design selection; it may therefore differ from one embodiment to another according to application.

Similarly, it is not difficult to imagine the possibility of replacing the guide channel 2 with equivalent means, that is, means which can support the tubes to be introduced into the processing machine situated downstream of the apparatus according to the invention, or at least a longitudinal portion of the tubes. Furthermore, the production of apparatus according to the invention in which the aforementioned guide channel is completely missing should not be excluded; in fact, a situation can be imagined in which the rollers of the feed-device are of a length such that they can support a tube to be introduced into the downstream machine without the need for the support provided by the guide channel of the embodiment described above; the usefulness of this would presumably be limited to the processing of short tubes or bodies.

As a further variant, when a channel or other guide means is present, a position of the tube-feed device different from that of the preceding embodiment could be provided for; that is, the possibility of apparatus according to the invention having the tube-feed device disposed upstream of the guide channel or means rather than downstream as considered above should not be excluded. Although a variant of this type appears less preferable than the embodiment described herein since problems could arise in the introduction of the head end of a tube into the downstream processing machine, it should nevertheless not be considered impracticable.

These and any further variants in any case fall within the scope defined by the following claims.