BACKGROUND OF THE INVENTION The metal cages used as reinforcement elements in reinforced concrete structures comprise a plurality of longitudinal rods with which stirrups are associated at longitudinal intervals.

Assembling the cages can be done manually or partly automatically, but in any case it is long and complex, particularly in reciprocally positioning and distributing the stirrups and longitudinal rods, since the assembly workers are obliged to carry out continuous measurements before attaching them, and there is a high probability of error.

Even when partly automatic machines are used, it is very problematic to correctly position the welding assemblies, to position the round pieces in the correct attachment positions, to insert the longitudinal rods inside the perimeter of the stirrups, to move the partly or entirely assembled cages, and other operations.

Moreover, the variety in the structure of such cages obliges the producer to make a personalized production, almost exclusively to order.

There has been a proposed solution wherein, in a first step, a substantially standardized pre-cage is made, by attaching two auxiliary round pieces outside the stirrups, and in a second step, and in a second zone, the cage is completed with the rods according to specifications.

However, this solution does not solve the problems of

positioning and centering the stirrups with respect to the welding assemblies at the desired heights, of feeding the auxiliary round pieces and of inserting, in the second step, the rods according to specifications inside the stirrups and of handling the pre-cage/completed cage.

The present Applicant has devised and embodied this invention to overcome these shortcomings and to obtain other advantages.

SUMMARY OF THE INVENTION The invention is set forth and characterized in the respective main claims, while the dependent claims describe other characteristics of the invention.

The purpose of the invention is to achieve reinforcement cages comprising at least two longitudinal round pieces attached to the stirrups so as to facilitate the positioning and centering of the stirrups in the assembly step, and also the vertical and transverse positioning of the round pieces to be attached to the stirrups at the correct heights according to the design specifications.

The device to make reinforcement cages according to the invention comprises at least: -step-wise feed means for the longitudinal round pieces to be attached to the stirrups, -means to position at least one stirrup at a time, -at least one work assembly for at least each one of said longitudinal round pieces, and -a supporting plane on which the cage or pre-cage is progressively formed.

In a first embodiment, the feed means consist of drawing means with rollers.

According to a first variant, the feed means consist of gripper means with alternate movement, while in another variant, the feed means consist of track means, or chains,

or other similar or identical systems.

In a first embodiment, the work assembly comprises, for each round piece, at least attachment means able to make the round piece solid with one or more stirrups simultaneously, which stirrups are located on each occasion in the positioning means.

The attachment means, in the preferential embodiment, consist of one or more welding assemblies.

According to a characteristic feature of the invention, the supporting plane and the work and feed assemblies cooperating with the round pieces have a reciprocal position which can be regulated at least vertically, in order to regulate the attachment height at which the round pieces fed by said work assemblies are attached to the relative stirrups resting on said supporting plane.

In a first embodiment, at least one work assembly located on one side with respect to the attachment position of the stirrup is vertically and laterally fixed, while the at least one work assembly located on the other side of the stirrup is movable both laterally and vertically with respect to the fixed supporting plane.

In the event that there are two or more work assemblies on one side of the stirrup, opposed to one or more work assemblies located on the other side, a preferential embodiment provides that at least one assembly located on one side is fixed vertically and laterally, while the assembly or assemblies located on the other side are movable vertically and laterally.

This allows to have a fixed reference at all times, on one side, with respect to which the stirrups can be positioned, and to regulate the position of the work assemblies afterwards, according to the shape and size of the stirrup to be used, moving only the assemblies arranged on the

opposite side to the fixed reference.

In the preferential embodiment, the two work assemblies located on the same side of the stirrup are mounted on a common structure suitable to move laterally according to the shape and size of the stirrup, and on which one of the two assemblies is able to move vertically.

In this way, with only two movements, a lateral one to move said common structure nearer to or farther from the fixed reference, and a vertical movement of one of the two assemblies located on the same side, it is possible tc pre- set the device substantially according to every shape and size of the stirrups to be used.

In another embodiment, the two assemblies located on the same side are movable vertically and move together; according to a variant, the two assemblies move separately and independently.

According to another variant, all the work assemblies move together at least vertically with respect to the fixed supporting plane. In a further embodiment, the supporting plane is movable at least vertically with respect to the fixed work assemblies.

In still another embodiment, both the supporting plane and at least some of the work assemblies are movable at least vertically.

The movements of the work assemblies and/or the supporting plane are advantageously managed by a control unit able to memorize the positions which said assemblies and/or said plane assume according to the width and/or height of the stirrup, so that the whole device can be regulated automatically after the stirrup size data has been inserted.

According to another feature of the invention, the work assembly comprises means able to achieve, on each round piece and in a manner correlated to the feed step, one or

more loops in relation to the position of the stirrup or stirrups and distanced lengthwise. Each loop has a depth substantially mating with the diameter of the rod of the specific stirrup to be connected and is arranged, with respect to the previous and subsequent loop, at an interaxis substantially equivalent to the specification interaxis of the cage. The loops are aligned lengthwise on at least one round piece of the cage and have a convex shape facing outwards; they define the seatings in which the stirrups cooperate with and are then attached to said round pieces.

According to a variant, on the supporting plane on which the cage is progressively formed, the specification rods which have to be inserted inside the stirrups in order to complete the cage are deposited.

In a preferential embodiment, the supporting plane has or cooperates with means to keep said rods at least temporarily raised, in order to allow the lower side of the stirrups to pass. These lifting means are able to allow the free advance of the stirrups without interfering with them, allowing the rods to be progressively inserted inside the stirrups as the cage is gradually formed and as a growing number of stirrups advance on the supporting plane.

According to another feature, the device comprises means to make the stirrups in a manner which is functionally and temporally correlated to the formation of the cage on the supporting plane by said work assemblies. The means to make the stirrups, in a further embodiment, are associated with automatic loading means able to pick up on the prepared stirrups one by one and to put it between the round pieces advancing step-wise, in the seating defined between the loops made thereon.

BRIEF DESCRIPTION OF THE DRAWINGS These and other characteristics of the invention will

become clear from the following description of some preferential embodiments, given as a non-restrictive example, with reference to the attached drawings wherein: Figs. la-ld show schematically, with a view from above, a device to produce reinforcement cages according to the invention in the various steps of the work cycle; Fig. 2 is a prospective view of a cage made with the device shown in Fig. 1; Figs. 3a-3c show schematic side views of a detail of the device shown in Fig. 1; Fig. 4 shows a preferential embodiment of the invention; Figs. 5a-5b show another embodiment of the invention, with a variant of Fig. 4; Fig. 6 shows another variant of the invention; Figs. 7a and 7b show another variant of the invention, in two positions.

DETAILED DESCRIPTION OF SOME PREFERRED FORMS OF EMBODIMENT In the attached Figures, the number 10 indicates in its entirety a device to produce reinforcement cages or pre- cages 11 consisting, in this case, of three longitudinal round pieces 13 and at least some of the stirrups 12 which will constitute the finished cage. The round pieces 13 are attached outside the relative stirrups 12 and may be auxiliary rods, or specification rods, that is to say, having a structural function as well as connecting the stirrups 12, particularly in smaller cages 11.

The invention is applied also to cages or pre-cages 11 comprising two, four or more outer round pieces 13, which can cooperate with the upper or lower sides or with the corners of the stirrups 12.

The device 10 comprises, for each of said longitudinal round pieces 13, feed means 16 and straightening means 21.

The feed means 16 comprise, in this case, a drawing

assembly with rollers 116 able to unwind a longitudinal round piece 13 from a relative roll (not shown here) and to draw it through the respective straightening means 21. The straightening means 21 comprise, in this case, two assemblies of rollers, respectively 121a and 121b arranged and acting on two planes orthogonal to each other.

According to a variant not shown here, there is a single drawing assembly with rollers 116 for all three longitudinal round pieces 13. According to another variant which is not shown, the feed means comprise alternate motion grippers, chains, tracks or other identical or similar means.

The device 10 also comprises, for each round piece 13, a work assembly 14 equipped with at least attachment means 18 to attach the round piece 13 and the relative stirrup 12, and a supporting plane 20 arranged downstream of the work assemblies 14 and on which the cage or pre-cage 11 is progressively formed.

Between the drawing assembly 116 and the relative attachment means 18 there may be a guide tube for a relative longitudinal round piece 13.

The supporting plane 20 extends at least as far as a position below the attachment means 18 so as to constitute a lower supporting element for the stirrups 12 as they are positioned one after the other in the welding or tying position.

The attachment means 18 for each round piece 13 comprise at least a welding element 118 able to move from an inactive position, wherein it is distant from the relative round piece 13, to an active position wherein it approaches the round piece 13 to attach it to the stirrup 12.

In this case, each welding element 118 cooperates with a pressure element 15 which intervenes in the welding step, holding the stirrup in a very close position to the relative

round piece 13 and facilitating an efficient and long- lasting weld. Each welding element 118 is also associated with at least a guide and centering element 34 able to cooperate with a relative stirrup 12 when it is inserted between the round pieces 13 and welded thereto.

In this case, the work assembly 14a located on one side of the stirrup 12, represented by the welding element 118 and the relative guide and positioning element 34, is vertically and laterally fixed, so as to constitute a reference element for the first positioning of the stirrups 12; on the contrary, at least one of the assemblies 14b and 14c located on the other side of the stirrup 12 is movable both laterally and vertically in the direction 35.

In a first embodiment, shown in Fig. 5, the assemblies 14b and 14c are mounted on a common structure 38 able to move laterally in the direction 36, towards and away from the work assembly 14a located on the opposite side, so as to regulate their position according to the width of the stirrup 12 used; one of the two assemblies, in this case 14b, is movable vertically along the common structure 38 so as to be able to regulate its own position according to the height of the stirrup 12. In this way, two regulation movements only, one lateral and one vertical, allow to adapt the position of all the work assemblies 14a, 14b, and 14c substantially to every shape and size of the stirrups 12.

According to a variant, the work assemblies 14b, 14c are both movable vertically together by means of vertically moving the common structure 38, whereas, in the embodiment shown in Figs. 5a, 5b, said assemblies 14b and 14c are movable independently from each other.

According to this last embodiment, the two assemblies 14b and 14c are associated with respective threads 38a and 38b, with opposing direction screw, of a threaded shaft 40

cooperating with a drive motor 39; when the motor 39 is activated, it causes said assemblies 14b and 14c to be displaced in opposite directions to be positioned at the attachment heights of the respective round pieces 13 according to the height of the stirrups 12.

In another variant, shown in Fig. 6, the assemblies 14a, 14b and 14c are movable vertically all together, as substantially the entire feed and attachment device is movable vertically with respect to the fixed supporting plane 20.

According to a further variant shown in Figs. 7a, 7b, which show two working positions, the supporting plane 20 is movable vertically in the direction 37 with respect to the fixed work assemblies 14 in order to vary the attachment height of the round pieces 13 in relation to the height of the stirrups 12.

In the embodiment shown here, upstream of the attachment means 18, the work assembly 14 comprises punching means 17 able to make a relative loop 22 on each round piece 13, in a fashion correlated geometrically and temporally to the positioning of the stirrups 12 with respect to the round pieces 13. The loop 22 has a convex shape facing outwards and a depth substantially mating with the diameter of the rod of the specific stirrup 12 to be connected.

The loops 22 made on the round pieces 13 define a seating into which a stirrup 12 is inserted and held in a substantially erect position, orthogonal to the longitudinal round pieces 13.

In the embodiment shown here, in a position cooperating with the work assemblies 14 and with the supporting plane 20 there is an assembly 25 able to make stirrups 12, starting from metal bar or wire, according to a cycle correlated to the cycle to form the pre-cage 11.

The assembly 25 comprises at least bending means 26, means 27 to feed the bar, and shearing means 28. The assembly 25 also comprises means 29, in this case of the gripper type, able to pick up each individual formed stirrup 12 one after the other and to transfer it automatically to the position where it is attached to the round pieces 13.

The means 29, in this case, are able to insert and release the stirrup 12 from above, between the loops 22 present on the round pieces 13 in correspondence with the position where it is attached to the round pieces 13. Instead of the gripper-type means 29, the assembly 25 may provide automatic arms, movable planes, translators or other means suitable for the purpose.

When the assembly 25 is not present, or only comprises means to make the stirrups 12, the action of the means 29 can be carried out by an operator who inserts the stirrups one at a time from above between the loops 22 made on the round pieces 13 and rests them on the plane 20.

The cycle to form the cage 11 provides that the round pieces 13 are fed forwards, by the relative feed means 16, after the work assemblies 14 and/or the supporting plane 20 have been correctly positioned in height, until they are in correspondence with the punching means 17; then the feed is stopped and the loops 22 are made on the round pieces 13 by the relative means 17.

In parallel, the assembly 25 forms a stirrup 12 which is handled by the means 29.

Then the round pieces 13 advance until the loops 22 are positioned in correspondence with the attachment means 18 and in this position at least one stirrup 12 prepared by the assembly 25 is picked up by the means 29 and located between said loops 22. The stirrup 12, welded to the round pieces 13, is made to advance on the supporting plane 20 for a step

mating with the specification interaxis, and the means 17 are again made to act on the round pieces 13 to form new loops 22.

Then the cycle of feeding, positioning and attaching a stirrup 12 is repeated for a second stirrup 12 and then for a third, and so on; the forming cage 11 advances on the supporting plane 20 due to the thrust action of the drawing assembly 116.

Every work assembly 14 also comprises shears means 19 which in this case are arranged downstream of the relative welding element 18.

The shears means 19 are able to cut the relative round pieces 13 when the cage, or pre-cage, 11 is complete, or when there is a blockage or other problems which require the work cycle to be interrupted.

In the embodiment shown here, the cycle to make the pre- cage 11 provides to position definitive longitudinal rods 30 according to the design specifications already inside the perimeter of the stirrups 12 as the pre-cage 11 gradually forms on the supporting plane 20. To obtain this, the invention provides to position the rods 30 keeping them slightly raised with respect to the plane 20 so as to allow the stirrups 12, and particularly the lower side of the stirrups 12, to pass freely below the rods 30.

In the embodiment shown in Figs. 3a-3c, along the work plane 20 there are two rollers 31 of the type with rigid radial blades 32, arranged with their axis substantially orthogonal to the direction of feed of the stirrups 12 on the plane 20. The rollers 31 are arranged partly below the surface of the supporting plane 20 so that the radial blades 32, in this case six of them, protrude from the plane 20 and keep the rods 30 raised with respect thereto.

The first stirrup 12 advancing on the supporting plane 20

can thus pass with its lower side below the rods 30 (Fig.

3a) and, when it meets the first blade 32 (Fig. 3b), it makes it rotate, with the relative roller 31, and can thus continue its advance without interference (Fig. 3c).

A11 the stirrups 12 in the pre-cage 11 can advance in this way so that, when the pre-cage 11 is complete, the rods 30 as laid down by the specifications are already inside the perimeter of the stirrups 12. In this way, in a second stage and in a second finishing zone of the cage, it is not necessary to make the complicated operation of inserting the longitudinal rods, which can even reach twelve metres in length, inside the stirrups 12 after the pre-cage 11 has been completed.

The pre-cage 11 thus made, with the definitive rods 30 already inside, can be translated to an adjacent zone for finishing where the rods 30 can be attached, either manually or partly automatically.

Modifications and variants may be made to the invention, but these shall remain within the field and scope thereof.

In an alternative embodiment, it is the punches 17, which in this case are movable lengthwise according to pre-determined travels, which feed the round pieces 13.

The round pieces 13 can also be attached to the relative stirrups 12 also in correspondence with the lower or upper side, or in correspondence with the corners. Moreover, supplementary means may be provided able to support the stirrups 12 during the operation to attach them to the longitudinal rods 13. In the event that longitudinal rods 13 are used in the form of bars sheared to size, the shears 19 may be omitted.