MANUFACTURING OF THREE-DIMENSIONAL, METALLIC AND RETICULAR CAGES SUPPLIED WITH TRANSVERSAL STIRRUPS EXTERNALLY FORMED AS REGARDS THE LONGITUDINAL BARS AND DIRECTLY ELECTRO- WELDED ON THE SAME

Field of application

The present invention relates to an automatic machine for the uninterrupted manufacturing of three-dimensional, metallic and reticular cages supplied with transversal stirrups externally formed as regards the longitudinal bars and directly electro-welded on the same. These products are used normally to reinforce concrete castings in the building sector in general.

The machine is characterized by a technical solution that is distinctly different from other similar ones already known in the field, highlighting especially: the reduction in the number of automatic bending chucks for the transverse bars, because it uses only two, an upper one and a lower one; the possibility to insert longitudinal longerons in addition to the ones at the corners of the transverse geometrical figure; the possibility to provide any geometrical figure having a regular or irregular transverse cross-section; the possibility to electro-weld all the longerons to the transversal stirrups; the very low maintenance and operating cost of the machine; the highly competitive production cost of the product for an equal production of finished product.

Background art

In the current background art, various automatic machines are known for the uninterrupted manufacturing of three-dimensional, metallic and reticular cages supplied with transversal stirrups using bars or straight metallic wires previously straightened by other machines.

Some of these machines use manual or automatic tying with metallic wire of the transversal stirrups on the longerons: however, they have drawbacks because the intervention of at least one operator directly on the cages is required, and therefore the production times are longer than a fully automatic machine such as the one according to the present patent, and in any case the quality of the mutual tying of the various elements involved is not constant indeed due to the intervention of more or less skilled and expert personnel.

The machine derived from Dutch patent no. 1030978, dated 23 January 2006 (Verschuren Gerardus Alexander) is known which uses expensive means that affect considerably the final cost of machine, such as robots for the electro-welding between the longerons and the transversal stirrups. Moreover, it has fixed standard templates for the longeron sliding guides, which affect the production costs and the tooling costs of the machine. Furthermore, it uses a pair of chucks or bending units that move on command on a circular path on a plane which is perpendicular to the cage forming direction: this is highly expensive due to the mechanism for the movement of said units. Ultimately, this is a high-technology machine which has however a very high commercial price, and therefore the invention is of limited commercial interest indeed due to the high production cost of the machine.

Another known machine is the one related to Austrian patent no. A

510/2009 dated 31 March 2009 (EVG Entwicklung Verwert Ges) (WO 2010/1 11723), which uses four chucks or corner bending units, each enabled to perform a single bending of the transversal wire around the longitudinal longerons.

However, this technical solution points out several drawbacks: the automatic management of all of four bending units of a complex type, also provided with an electric spot welder, a moving arm for transversal guiding of the wire, and an element for deforming the transversal wire during the second bending of the final hook. These complex units are highly vulnerable in their continuous and repeated functionality, with a consequent high rate of maintenance due to the wear of the parts, and furthermore they have safety problems as regards their electrical insulation.

It has been thought, therefore, to overcome the drawbacks cited above by providing a fully automatic and versatile machine that has adequate technology and is capable of providing products that have various transversal sectional geometric shapes, with a plurality of longitudinal longerons with transversal stirrups which are electro-welded to the longerons, be they corner ones or not: this at a manufacturing cost that is very modest in relation to the performance provided.

Summary of the invention

The aim of the invention is to provide an automatic machine that is specialized exclusively in the uninterrupted manufacturing of three- dimensional metallic reticular cages which are prism-shaped, with bars that constitute the longitudinal longerons and the transversal stirrups that wrap around said longerons, the latter being derived from straight bars or metallic wires which are bent and cut to size on the spot, and then immediately electro-welded to the longerons in a subsequent station, which have the following main technical characteristics:

- two chucks or bending units adapted to bend transversal metallic bars with respect to the longitudinal longerons, which are mutually opposite, one operating at a lower horizontal height and the other one operating at an upper horizontal height, capable of being moved and positioned correctly on automatic command along the respective horizontal guide for the transverse sliding with respect to the advancement of the longerons, thus forming the reticular cage;

- the lower horizontal guide for the sliding of the bending unit is fixed at the same entry height of the straight bar that constitutes the transversal stirrup for wrapping around the longerons;

- the upper horizontal guide, which is parallel to the preceding one, for the horizontal sliding of the respective bending unit. Said guide can also move on command in a vertical direction and can slide in turn on two shoulders or vertical guides: this is done so as to move the respective upper bending unit to any height with respect to the lower one in order to provide any vertical dimension of the transversal stirrup and therefore also of the reticular cage being formed;

- each bending unit is formed by a circular sector of a toothed wheel which is pivoted at its center and the ends of which form the bending points for bending in a clockwise and counterclockwise direction;

- the machine is furthermore provided downstream with an automatic unit for the longitudinal movement of the cage being formed, which is mounted on an adapted carriage that moves in the same direction in which the cage is formed, and is provided with multiple automatic clamps which grip the ends of the longerons in order to produce the advancement of the cage by the desired spacing;

- the machine is provided, proximate to the horizontal guides of the bending units and in the vertical shoulders, with adapted adjustable guiding templates for the sliding in the correct position of the longerons that are not in corners but in the perimeter that is internal to the transversal stirrups, in order to comply with the calculation plans of the reticular reinforcement frames where reinforcement longerons are provided;

- finally, an automatic electro-welding assembly that is capable of performing spot welding, i.e., the joining between the longitudinal longeron and the transversal stirrup that has just been bent. This automatic electro- welding assembly is provided with automatic positioning of the electrode supporting device which is continuous, proximate to the corner longerons and/or in any intermediate position.

Essence of the invention

The aim and objects of the invention are achieved according to the characteristics of the main claim and/or of any other claim presented in this patent text. The main aim of the present invention is to provide an automatic machine for the uninterrupted manufacturing of three-dimensional metallic and reticular pages, or reinforcement frames for concrete castings, complete with transversal stirrups formed externally as regards the longitudinal bars and directly electro-welded to said bars. The cage manufacturing machine is automatic and is programmable and controllable in its operations by means of computer systems that are known to persons skilled in the art. It is capable of manufacturing cages of any transverse sectional shape and is capable of using a plurality of longitudinal longerons, be they in a corner position or in any intermediate position, thus meeting the requirements of design and of structural calculation. The bars that constitute the longerons of the cages can have any cross-sectional dimension and be guided by adapted special guides for the corner ones, which are movable and can be positioned automatically on a vertical plane and are of a simple type for the longerons in an intermediate position, manually adjustable at the time of machine tooling.

The cage manufacturing machine, again automatically, manufactured the transversal stirrups for joining to the longitudinal longerons, bending them at the corners so as to wrap externally around said longerons and at the same time electro-welding the points of contact between said longerons and the stirrup being formed.

The transversal stirrups are formed one at a time with desired spacings which are constant or not.

Another characteristic of the present invention resides in that the machine has a fixed lower horizontal cross member, which is perpendicular to the cage forming direction and is supported by two lateral vertical shoulders. This cross member forms the guide for the controlled sliding of a lower bilateral bending unit which works on a vertical plane. It is capable of arranging itself automatically proximate to the corner where the bending of the transverse straight bar is to be performed, thus forming the stirrup. Once bending has been performed, connection between the longeron and the stirrup is possible by means of an electro-welding unit of the continuous- wire type or other equivalent type, capable of arranging itself and operating automatically in the desired point.

Likewise, another upper horizontal cross member is provided for the sliding of another upper bilateral bending unit which works on the same vertical plane, in opposition to the lower one. This last cross member is movable on a vertical plane, since its ends slide on two vertical guides which are parallel to said lateral shoulders: in this manner it is possible to provide transversal stirrups of any size.

Since the established technique in the forming of transversal stirrups for binding or wrapping longitudinal longerons requires the closing of the stirrup with the provision of an end hook on a longeron, there are no problems for the first end: the bending unit performs a bend with a larger angle, while for the execution of the final hook it is necessary to divert it during its execution in order to avoid overlap on the first one, arranging it to the side. In this manner, the second hook also has part of its lateral surface in contact with the longeron, thus allowing its electro-welding to said longeron.

Indeed due to the alternation between corner bends of the transversal stirrup and the preceding electro-welding between the longeron and the bent stirrup, and/or the electro-welding of the intermediate reinforcement longerons optionally provided to said stirrup, with the execution of the electro-welding of the second hook to the stirrup^ said stirrup is finished and locked to the longerons and therefore the cage being formed can advance by the desired spacing for a new cycle of bending a new stirrup.

According to another characteristic of the present invention, the perforated guides, which are mutually parallel, are adapted for the sliding of the longerons arranged at the corner. They can be positioned on a vertical plane that is transversal to the production flow and are supported upstream on the same horizontal cross member for the guiding of the bilateral bending units, have the function of keeping in position the respective longeron and at the same time contrasting the bending force during the step of perpendicular bending of the stirrup around said longeron, which acts as a fulcrum point.

According to with another characteristic of the invention, the machine has downstream, and able to slide on adapted guides, a transverse carriage for the automatic forward traction of the cage being formed. It is provided with a series of automatic grip clamps (for example four in the case of four longerons), which have the task of gripping the end of the longerons in order to be able to produce the advancement of the cage once it has been finished and once the transversal stirrup has been finished and welded.

Ultimately, the present machine fully achieves the intended aim and objects, i.e., to provide a fully automatic machine that is capable of manufacturing uninterruptedly prism-shaped tubular metallic reticular cages having rectilinear parallel longerons which are wrapped, with programmed spacings, by transversal stirrups which are bent correctly directly on the corner longerons and are locked in position directly after their bending by means of adapted electro-welding means of the continuous-wire type or of an equivalent type, also of the automatic type. The resulting product is provided fully automatically by the machine, without manual interventions inside it, fully avoiding the danger of accidents or injury, but only for its computerized programming and its functional control. The automatic cage manufacturing machine therefore ensures the constancy and repeatability of the product.

Description of drawings

These and other characteristics of the present invention will become apparent from the following description, by way of preferential example of production, which in any case is nonlimiting, in the nineteen accompanying drawings, wherein: Figure 1 is a perspective view of the apparatus for forming metallic reticular cages which includes the automatic cage manufacturing machine of the present invention;

Figure 2 is a perspective view of a reticular cage having a rectangular cross-section with longerons at the corners and in intermediate positions, with transversal stirrups with different spacings;

Figure 3 is a perspective view of a reticular cage with a square cross- section with transversal stirrups with different spacings;

Figure 4 is a front view of the automatic cage manufacturing machine, highlighting the parts that are essential for operation with an example of a cage having a rectangular cross-section;

Figure 5 is a side view of the machine of the preceding figure, highlighting the automatic carriage for traction of the longerons of the cage being formed;

Figure 6 is a partial perspective view of the central region of the cage manufacturing machine, highlighting the guides for the sliding of the corner longerons of a cage having a square cross-section, and the two opposite bilateral bending units, an upper one and a lower one;

Figure 7 is a front view of the cage forming machine in the first step of insertion of the transverse rectilinear bar, which will be bent and will form the stirrup for wrapping around the longerons;

Figure 8 is a front view of the second step, i.e., the 90° right lower corner bending;

Figure 9 is a front view of the third step, i.e., the electro-welding between the curve of the stirrup and the respective corner longeron;

Figure 10 is a front view of the fourth step of the forming of the stirrup, i.e., the right upper corner bending with the upper unit and the repositioning of the lower one;

Figure 1 1 is a front view of the fifth step, i.e., the electro-welding of the bend that has just been formed with the respective right upper longeron; Figure 12 is a front view of the sixth step, i.e., the bending of the first end hook in the upper left upper point, and the simultaneous repositioning of the lower bending unit;

Figure 13 is a front view of the eighth step, i.e., the electro-welding of the bend that has just been provided with the respective left upper longeron;

Figure 14 is a front view of the ninth step of the forming of the stirrup with the execution of the cutting to size of the bar and the repositioning of the upper bending unit;

Figure 15 is a front view of the tenth step, i.e., the left lower corner bending of the stirrup;

Figure 16 is a front view of the eleventh step of electro-welding between the bend that has just been formed and the respective left lower longeron;

Figure 17 is a front view of the twelfth step of repositioning the lower bending unit, ready for a new cycle;

Figure 18 is a front view of the thirteenth step of final bending of the second end hook to the side of the first hook, in the left upper corner;

Figure 19 is a front view of the fourteenth step that provides for the electro-welding of the second end hook with the left upper longeron;

Figure 20 is a front view of the fifteenth step, i.e., the repositioning of the two bending units and the insertion of a new transversal bar to begin a new stirrup forming cycle. The cage, in the meantime, has been made to advance by the desired spacing with the carriage downstream, in order to allow to provide a new stirrup around the corner longerons.

As can be seen from the accompanying figures, the automatic machine 10 is designed for the continuous manufacturing of three- dimensional metallic reticular cages having any sectional geometrical configuration (for example square, rectangular, etc.) having transverse wrapping stirrups 18 and 18.1 with constant or non-constant spacings, so as to wrap externally around the longitudinal corner longerons 17 and the intermediate ones 17.1.

The cage manufacturing machine 10 is inserted in the production line of reticular cages for the building sector in a transversal manner: upstream, a series of supporting arms 16 is provided for the rectilinear bars that constitute the corner longerons 17 and the intermediate longerons 17.1 , while the bar of the stirrup is obtained from a vertical coil supporting assembly 12, which unwinds it and is straightened by an adapted straightening unit 13, and by the perpendicular guiding unit 19 before it is inserted in the cage manufacturing machine 10. Downstream of the cage manufacturing machine there is the path 14 for the sliding of the cage being formed and the evacuation path 15. Also downstream there is an automatic traction carriage 11 for the ends of the longerons in order to cause the advancement of the cage by a programmed spacing whenever a transversal stirrup is finished.

The cage manufacturing machine is constituted by two lateral vertical shoulders and by three parallel horizontal cross members, an upper one for the connection and consolidation of the shoulders, a fixed lower one 20 arranged at the height of the working plane and of the bar entry plane, which is rectilinear and transverse 32 for forming the square stirrup 18 or rectangular stirrup 18.1, and an upper one 21, which can move on command vertically and can slide on command on the vertical guides 22. A movable bending unit, 23 and 24 respectively, slides in each one of the two cross members 20 and 21 and can be positioned automatically in any point of the corresponding beam. The bending units are mutually opposite and comprise a particular bilateral bending lever 25, which is constituted externally by a toothed wheel which is shaped like a circular sector, so as to highlight two lever points on the right and on the left in order to act directly on the bar 32 of the stirrup to be bent. There is an automatic advancement unit assembly 19, which is lateral and transverse with respect to the central assembly of the machine, for the bar 32, so as to correctly direct it and cut it to size in the stirrup completion step.

The machine shown in Figure 4 represents the manufacture of a cage having a rectangular transversal cross-section 18.1 , with horizontal longer sides and vertical shorter sides, and is provided upstream with guiding elements for the longerons 17.1 that are not corner longerons, 26 in the vertical portions and 27 in the horizontal portions. These elements are intended to guide and keep in position the non-corner longerons in the forming of the reticular cage, while for the corner longerons 17 there are particular tubular guides 28 for their advancement and a profiled terminal with a connector where the bending of the rod of the stirrup around the respective longeron will occur.

Downstream of the main part of the cage manufacturing machine 10 there is a particular carriage 1 1 with a lower trolley 29, which can move on command in the cage forming direction, by gliding on the bench 14. It is provided with automatic clamps 30 (for example four, one for each corner longeron 17), which are adapted to grip the ends of the longerons by means of their positioning device 31 and pull them forward on command, pulling the entire cage being formed, if the last transverse stirrup for wrapping around said longerons is completed.

Figures 7 to 20 are views of the various steps of the automatic work of the machine in order to form the stirrup 18 for wrapping externally as regards the longitudinal longerons 17, having a square cross-section with four corner longerons. The numerals 1 , 2, 3 and 4 designate the corner guides 28 for the longerons 17 on which first the bendings with the bilateral automatic bending units 25 of the transverse straight bar 32 for forming the stirrup 18 are performed and subsequently with the intervention of the various units 33 for the automatic electro- welding with continuous wire or another suitable means for the purpose. Electro-welding occurs between the longitudinal longeron 17 and the curved part of the transversal stirrup so as to mutually stiffen the parts. The ends of the transversal stirrups are curved so as to form an initial hook 34 and a final hook 35 on the same longeron and again electro-welded.

Once the stirrup 18 has been completed, the carriage 1 1 with the trolley 29 comes into action, moving by the desired spacing downstream so as to prepare said longerons 17 adapted to receive a new stirrup for a new cycle.

When the three-dimensional metallic reticular cage is completed, it is evacuated from the forming plane 14 in order to leave room for a new production, and the sliding carriage 1 1 with the automatic clamps 30 returns to the initial position in order to grip the ends of the longitudinal longerons and thus cooperate in coordination with the central part of the cage manufacturing machine.

The invention of course is not limited to the example of embodiment described above, starting from which it is possible to provide other embodiments and way of carrying it out, and the details of execution may in any case vary without thereby abandoning the essence of the invention as stated and claimed hereafter.