Field of application

The present invention refers to an automated apparatus for the differential advancement of metal rods and/or bars for the construction of rectilinear and/or curvilinear electro-welded elements, and associated production method, particularly adapted to the field of industrialised production of electro- welded flat metal nets and/or of three-dimensional curvilinear elements.

Such machine operates in line and on the same work surface in plants for forming metal nets and three-dimensional reticular structures, and its operation has been conceived as being completely automated i.e. managed with known automatic command and control systems, so that no manual intervention is required by operators within the continuous and automated production line.

The present invention consists in a machine composed of two similar automated assemblies facing each other, that operate in mutual coordination and in mutual cooperation, and which are mutually connected by an automated gripper crossbar with angular position controlled by suitable means. Such assemblies move in such a way as to individually implement differential programmed advancements, so determining programmed angular positions of the connecting crossbar and thus variously positioning the longitudinal rods to form nets or other electro-welded elements, so forming electro- welded reticular structures and/or simple flows of metal rods and/or bars that are rectilinear and/or curvilinear in shape, to the right and/or to the left.

State of the art

As of the current state of the art, in the field of automated plants for forming electro-welded metal nets and in the construction of three-dimensional reticular structures, such as for example reinforcements for concrete castings, movement of the products is achieved by means of sliding them on roller conveyors or transfer conveyors or with hanging means of movement from above in the same direction as the direction of flow of the production line: this is for making rectilinear products. If however it is necessary to produce curvilinear or curved elements, the plant and systems are manually altered, thus stopping the automated flow and bending the longitudinal wires or rods with suitable mechanical means.

Such technical solutions make reticular products or structures that are not perfect and which are much less constantly repeated over time: the curvatures lack precision because they are executed each time with tools and means that need to be manually adjusted, meaning that the experience of the specific personnel responsible has a bearing on the outcome.

DE 33 24 678 Al teaches an apparatus and a method for forming rectilinear and curvilinear products which has two vertically arranged cylinder actuators, each being hinged by means of a simple hinge to a transom. The latter known apparatus is rather complicated in view of its vertical arrangement of the cylinder actuator and is not suitable for working on large curvilinear grids, particularly in view of the limited flexibility of its two simple hinges. In addition, the apparatus of DE 33 24 678 Al can only form the curvilinear grids in one direction only, namely either left of right.

Therefore, the present automated apparatus comes to the rescue to compensate for the drawbacks found. Such apparatus ensures the operation of forming curvilinear with the required flexibility and, also rectilinear products with consistency and completely automatically without the manual intervention of operators on the plant production line. In this way the apparatus prevents: accidents, slowdowns in production, non-conforming products or products that do not come up to standard.

Aim of the invention

The aim of the present invention is therefore to devise an automated machine or apparatus for the differential advancement of metal rods and/or bars for the construction of rectilinear and/or curvilinear electro-welded reticular elements, that has the following and principal characteristics:

Be capable of being inserted in a production line for forming flat metal nets and/or three-dimensional structures, positioned upstream of the welding station that performs the automatic electro-welding between the longitudinal rods and the transversal rods;

Be capable of being used for forming both rectilinear and/or curvilinear products, both to the right and to the left;

Be a completely automated apparatus in which all operations involving movement of the wires or rods takes place without the direct intervention of operators inside the production line;

Be an apparatus that comprises two autonomous advancement assemblies, mutually connected by a gripper crossbar for gripping the longitudinal rods, the ends of which are hinged on such two lateral assemblies;

Have the lateral assemblies capable of advancing in a controlled fashion, with appropriate encoders of identical and/or different sizes, thus determining the angle of the gripper crossbar in its advancement and therefore achieving a greater travel on one side than that on the other side, in this way forming the curvature of the reticular product, be it flat or three-dimensional;

Description of the invention

The objectives of the invention are achieved according to the characteristics of the principal claim and/or of any other claim contained in this patent text, by means of devising an automated machine or apparatus for the differential advancement of metal rods and/or bars for the construction of rectilinear and/or curvilinear electro-welded elements and an associated production method, particularly adapted for use in automatic plants for forming flat and/or three-dimensional electro-welded metal nets, upstream of the electro-welding station.

The invention consists in a machine constituted, roughly speaking, by two horizontal lateral assemblies that are symmetrical with the central flow from which the longitudinal steel wires or rods that will form the electro-welded reticular product originate. Each assembly has the task of moving forward and backward independently and in a controlled fashion, and/or to operate in synchrony. Between such groups there is a crossbar, the ends of which are hinged on the moving parts of the two assemblies. In this way, varying the travel of the single lateral assemblies determines an angular position of the connecting crossbar, which is also fitted with special automatic grippers for gripping the metal wires or rods. Therefore the different travel or stroke of drawing the longitudinal wires determines their inclination in their proceeding forwards, and so welding the transversal wires with the longitudinal wires at constant intervals produces electro-welded curvilinear and/or rectilinear reticular elements.

Indeed, if the two lateral assemblies advance in synchrony with the same travel or stroke, the crossbar with the automatic grippers proceeds in the same direction in a position that is perpendicular to the flow of the longitudinal rods or wires, advancing longitudinal rods by the same length, and therefore obtaining a rectilinear finished product. But if a lateral assembly proceeds with one travel or stroke which is longer than the other, then the connecting crossbar, hinged, proceeds in its advancement in an inclined manner causing the longitudinal wires to also be drawn forward with different travel lengths, thus determining the angular inclination with respect to the normal advancement, to the right or to the left. In this case a curvilinear reticular product is obtained. To define a curvature to the right in the final product, the travel length of the right-hand advancement assembly needs to be adjusted by an amount that is less than that of the corresponding assembly positioned on the left, and vice- versa for a product with final curvature to the left.

Such connecting crossbar, hinged at its ends on the two controlled-movement side assemblies, is fitted with several automatic grippers, adapted for any diameter of the rods, which are correctly positioned along the crossbar with automatic or manual adjustments at the same intervals as those of the longitudinal rods.

Ultimately the present machine or apparatus enables the automated construction, obviously with the assistance of suitable means of automatic management and control known to technicians skilled in the art, of particular flat (planar) and/or three-dimensional reticular structures, such as for example electro-welded metal nets or three-dimensional curved and/or rectilinear elements without the direct manual intervention of operators on the plant itself.

An advantageous characteristic of the present invention is the way in which the crossbar connecting the two lateral advancement assemblies and fitted with automatic grippers is hinged. Indeed, to allow a complete range of angular positions of the crossbar with respect to the two side assemblies which are fixed but movable only longitudinally, the crossbar is hinged simply at one end while at the other end the crossbar is double- hinged, i.e. on a lever which is also hinged on the other controlled-advancement lateral assembly. The side and type of hinging is irrelevant: what is important is that the crossbar is at least hinged in a simple manner at one end, while at the other end it is necessary to have hinging that is indirect, articulated and defined on a free lever or on an arm.

The method for producing a curvilinear and/or rectilinear reticular product is very simple: all that is required is to establish, from the design data, the direction of the curve and the radius of curvature of the final product, to automatically intervene on the respective travels or strokes of the two lateral advancement assemblies, thus also determining the final angular position of the connection crossbar. After this the crossbar requires intervention by exactly positioning the automatic grippers for gripping and releasing, at established intervals for the longitudinal wires. Once the machine has been pre-adjusted, it is ready to operate continuously and automatically. It positions the crossbar with the automatic grippers in position upstream, inclined (with respect to a line perpendicular to the flow of the production line) if a curved product is to be made: the grippers grip the wires or longitudinal rods, after which the two lateral groups advance along their pre-set travels or stokes until they reach the perpendicular line of the crossbar. In this position the automatic electro-welding station performs the welding of the transversal rod to the longitudinal rods. Lastly, the automatic grippers release the longitudinal rods and the two lateral advancement assemblies return to the starting position, bringing back such crossbar for a new advancement cycle. The transversal wires or rods are, each time, electro-welded downstream to the longitudinal wires or rods, in order to form a rigid product, before performing the advancement of such longitudinal wires with the crossbar.

According to another characteristic of the present invention, the distance between the two lateral advancement assemblies determines the width of the finished product: the same can also be said for the associated connecting crossbar which can be fitted with any number of automatic grippers and positioned automatically or manually in the setting-up phase.

The invention fully fulfills the set aims, i.e. those of: provide a completely automatic machine for the production of electro-welded flat and/or three-dimensional reticular elements, with curvilinear and/or rectilinear shape; the machine is capable of supplying curvilinear products both to the left and to the right; operator intervention consists only of the initial adjustment of the machine, then the processing is carried out completely automatically; devise a machine that is safe, conceived to prevent any accident on the part of the operator or operators of the plant; devise a machine that is automatic and reliable, in that being automatic it ensures the correctness and conformance of the finished product that is always the same, something that is not ensured by manual interventions.

Description of the drawings

A solution according to the present invention is shown for the purposes of preferred but non-limiting example, in the accompanying four drawings, wherein:

- Figure 1 shows, in a plan view, the apparatus for the differential advancement of the longitudinal rods or wires that constitute an electro-welded rectilinear metal net;

- Figure 2 shows, in a plan view, the machine in the previous figure, showing the formation of a net curved to the left, with the right-hand advancement assembly travelling a longer path or stroke than that of the left-hand assembly;

- Figure 3 shows, in a plan view, the machine in the previous figures, showing the formation of a net curved to the right, in which the right-hand advancement assembly travels a shorter path or stroke than that of the left-hand assembly;

- Figure 4 shows, in a plan view, the machine in the previous figure but enlarged so as to better show how the machine operates.

As can be seen from the various different figures, the automated machine or apparatus for the differential advancement of metal rods and/or bars for the construction of rectilinear (1) and/or curvilinear (1.1), (1.2) electro-welded elements, is constituted by two lateral advancement assemblies, to the left (14) and to the right (10), similar and facing each other, mutually connected by a crossbar (2) fitted with automatic grippers (7) that act on the rods (8). The ends of the crossbar are hinged respectively to the left at (3) and to the right at (4)(5)(6).

Each lateral advancement assembly involves the use at a minimum of a reduction gear (16) or (12) which is stepper controlled, with an output driven gear that acts on a rectilinear toothed rack (15) or (11), disposed in parallel with the longitudinal direction of flow of the bars (8). These toothed racks are integrally joined to the protruding hinging arm (1.3) or (9) and to the respective advancement assembly (14) or (10). In this way, the forward and backward actuation of the reduction gears (16) and (12) determines the advancement or retreat of the respective assemblies (14) and (10), according to the longitudinal direction.

The crossbar (2) at its left hand end, for example, is hinged simply at (3), while the other side is hinged in an articulated manner on a lever (5) at (4) and (6). Such technical solution is necessary to allow the crossbar to have a variable length of hinging, since it can be set to different inclinations with respect to the transversal direction and to the fixed and parallel distance of the two lateral advancement assemblies (14) and (10).

The machine is extremely advantageous in that it is fitted with computerised adjustment, control and management both of the individual paths of the two lateral advancement assemblies (14) and (10) and of the positioning of the automatic grippers

(7) along the crossbeam (2). This latter adjustment can also be manual, and will obviously be performed with the machine stopped. Obviously, the invention is not limited to the embodiment of the machine described above, starting from which other forms and other methods of implementation can be specified, and the details of execution may in any case change without departing from the description of the invention as stated and as claimed below.