EP0791416A1

EP0791416A1 - Method for the production of metallic cages for reinforced concrete and relative device

Info

Publication number: EP0791416A1
Application number: EP97102126A
Authority: EP
Inventors: Giorgio Del Fabro; Marcello Del Fabro
Original assignee: MEP Macchine Elettroniche Piegatrici SpA
Current assignee: MEP Macchine Elettroniche Piegatrici SpA
Priority date: 1996-02-22
Filing date: 1997-02-11
Publication date: 1997-08-27
Also published as: JPH09287292A; IT1288852B1; ITUD960022A1; IL120212A0; ITUD960022A0

Abstract

Method for the production of trellises or metallic cages for reinforced concrete, the cages consisting of a plurality of longitudinal rods (11a, 11b, 11c) supported by transverse support elements (13) supported by vertically movable carriages (14a, 14b, 14c), there being included a control unit (30), the method including the following operative steps:

the conformation of the cage is pre-set in the control unit (30);
at least the upper carriages (14a) are positioned to define the maximum working height;
the intermediate (14b) and/or lower (14c) carriages are positioned in a position which is functionally correlated to the positioning of the upper carriages (14a);
the longitudinal rods (11a, 11b, 11c) are inserted at different heights on the relative transverse support elements (13);
the movable carriage (18) supporting at least the desired number of stirups (12) is positioned in cooperation with a position substantially at the leading end of the longitudinal rods (11a, 11b, 11c);
the movable carriage (18) advances to the position where the first stirrup (12) is placed;
the movable carriage (18) halts and the operator removes the first stirrup (12) from the movable carriage (18), positions it on the upper longitudinal rods (11a) and performs at least a welding or tying operation;
the movable carriage (18) starts again and reaches the second position where the second stirrup (12) is placed and the operator intervenes to fix the stirrup (12) to the upper longitudinal rods (11a), and so on for all the other stirrups (12),

the method also including the retraction of the transverse support elements (13) when there is a condition of interference with the advancing movable carriage (18).
Device to carry out the above method, which comprises:

a plurality of transverse supporting elements (13), which are associated with the relative carriages (14a, 14b, 14c) movable at least vertically, to support the longitudinal rods (11), the transverse support elements (13) being separated vertically and defining groups of transverse supporting elements (13) separated lengthwise, each of the transverse support elements (13) being axially movable,
a supporting and displacement structure (17) for a movable carriage (18), the structure (17) being located on an upper plane parallel to the planes of positioning of the longitudinal rods (11), the movable carriage (18) including at least one supporting arm (19) suitable to uphold in a suspended position a plurality of stirrups (12), the movable carriage (18) stopping around the longitudinal position where the stirrup (12) is placed on the longitudinal rods (11);
a control unit (30) which manages the movement of the movable carriage (18) in the positioning of the stirrups (12) on the longitudinal rods (11).

Description

This invention concerns a method for the production of metallic cages for reinforced concrete, as set forth in the relative main claim.
The invention concerns also the device which carries out this method.
This invention is applied to the field of production of metallic cages for reinforcement purposes, the cages comprising a plurality of longitudinal rods, bars, shaped pieces or round pieces connected to each other by stirrups which are suitably separated lengthwise.
This invention makes possible the embodiment of metallic cages of any required section such as a square, rectangular, circular, T-shaped, triangular section, trellis, etc., either closed or open.
The invention is applied to make cages for reinforcement purposes with a length of at least 6/7 metres and widths of at least 0.5 metres.
The state of the art includes metallic cages, called also trellises, employed in building work to reinforce concrete in the production of pillars, beams or other structural elements having load-bearing functions.
These metallic cages consist of a plurality of longitudinal rods, such as bars, round pieces or shaped pieces, the number of which depends also on the calculation of the load-bearing capacity of the beam or pillar to which the cage is applied, the longitudinal rods being connected together by a plurality of transverse stirrups separated lengthwise.
The stirrup normally consists of a closed section, or a section which is open on one side, of a regular or irregular and generally polygonal or circular or other shape which defines the form of the metallic cage according to the requirements in question.
The longitudinal rods are located on the inside, or sometimes also on the outside, of the stirrups and are solidly secured thereto, normally but not necessarily at the corners of the same by welding or tying.
The production of these cages in the state of the art is mostly carried out with manual methods of a rather rudimentary type owing to the actual difficulty of automating even partly the performance of the working steps of the method.
The most common procedure is to rest the longitudinal rods on trestles suitably distanced from each other; the rods are separated from each other sideways by hand and approximately, and therefore without ensuring great precision, according to the size of the cage to be produced, and define the horizontal reference plane of the cage.
The stirrups are placed manually, one at a time, on the longitudinal rods at one or both ends thereof and are rested on the rods at the positions pre-arranged for their fixture.
The rods and stirrups are then welded or tied to each other, the partial cage thus produced is raised and further rods are inserted by hand which have to be positioned on a different horizontal plane; these rods are then connected, again by welding or tying, to the stirrups thus positioned.
It is clear that this procedure entails several disadvantages and working problems and often makes the task burdensome for the workers involved.
First of all the height of the supporting trestles determines the working height at which the workers have to operate and often compels them to perform the welding or tying at uncomfortable positions.
Moreover, the progressive placing of the stirrups at the right positions compels the workers to lift the rods whenever the stirrup arrives near the trestle on which the rods are supported, in order to allow the stirrups to pass.
Furthermore, the workers have to measure on each occasion the distance at which to place the stirrups which they are introducing, and this situation often entails inaccuracies and compels the workers to provide themselves with measuring equipment and to carry out an extra operation.
Besides, the operation of inserting the further rods after the first rods have been fixed to the stirrups entails great working difficulties since these rods may be of great lengths, greater then 10 metres.
The result of this is that the area where the cages are assembled must have a working space at least twice the longitudinal size of the cage which is being produced.
A further drawback consists of the fact that there is no precise reference point for positioning those further rods on the different horizontal planes of a cage, and this situation often leads to mistakes and inaccuracies in the production of the cage and also to great working difficulties and wastes of time.
Solutions have been disclosed which employ tables on which are secured supporting ferrules for the insertion of round rods all placed on the same plane; these ferrules however, have the simple task, like the trestles mentioned above, of positioning some bars and then the stirrups.
Another method provides again for the use of stationary tables on which are positioned spring catches to secure and position the stirrups correctly.
Italian patent BO94A000053 discloses a method of production of a metallic cage whereby a pre-cage is embodied first of all which consists of a plurality of stirrups arranged on suitably separated parallel planes; to the outside of the stirrups are connected at least two auxiliary longitudinal rods.
When this pre-cage has been produced, the longitudinal rods required to complete the cage according to the specific requirements are inserted at a later stage.
This solution, while making possible a relative saving of the labour force and time employed inasmuch as, on the one hand, it enables a partial automation of some steps of the method to be obtained and, on the other hand, makes possible a saving of the ties since the stirrups are already fixed and separated by the welding with the auxiliary rods, entails just the same a plurality of drawbacks.
First of all, the auxiliary rods are not taken into account by the designers during their calculations either as welds at that critical point or as an additional weight, and this fact entails an increase of costs in the production of the cage and also a reduction of the distance between the rod and the external concrete, this reduction not being taken into account by the designers.
Moreover, the pre-cage, when embodied, has to be displaced from the machine and conveyed to a distance so as not to interrupt production.
Furthermore, when the pre-cage has been embodied, there remain the known difficulties of insertion of the longitudinal rods and of the relative ties/welds which are carried out with the traditional methods.
In addition to this, the insertion of these further rods is very complicated, particularly when the stirrups are very close to each other inasmuch as the workers normally have to put their hand in the space between two adjacent stirrups so as to pull the rod, and this fact may entail further difficulties.
Document WO-A-87/05544 describes a machine for the formation of metallic cages for reinforcement purposes which includes a stationary work station for the assembly of the stirrups.
This stationary work station comprises a position to stock the stirrups and a pre-stocking position which are alternated by rotating around a pin.
The longitudinal rods are progressively made to advance inside the stirrups and welded in a fixed position arranged immediately downstream of the stationary work station where the stirrups are stored.
This solution however does not solve the problem of the space occupied by the machine for forming the cages, which must in any case be double the size of the cage which is to be obtained.
Moreover, this solution involves considerable operating difficulties which derive from the fact that it is necessary to move the cage lengthwise as it is being formed, and, as the stirrups are gradually attached, the cage increases in weight.
Document DE-A-3324678 shows a solution which is substantially the same as that of WO'544 as described above; there is a work station where the stirrups are loaded and a welding station, both of which are substantially stationary.
The longitudinal rods are inserted between the stirrups and, as the stirrups are welded or tied to them, the partial cage thus achieved is made to move lengthwise.
This document DE'678 includes all the disadvantages mentioned above, and in particular the working space occupied by the machine and also the difficulties in moving lengthwise the cage which is gradually forming.
The present applicants have designed, tested and embodied this invention to overcome these shortcomings, which have been a subject of complaints by businessmen in this field for some time now.
This invention is set forth and characterised in the respective main claims, while the dependent claims describe variants of the idea of the main embodiment.
The purpose of the invention is to obtain a method and the relative device for the production of metallic cages for reinforced concrete, whereby the operations are facilitated and considerable savings are made possible in terms of operating costs of the labour force and wastes of time.
A further purpose of the invention is to automate the steps of positioning of the stirrups and of the longitudinal rods so as, on the one hand, to obtain greater accuracy of embodiment of the final product and, on the other hand, to relieve the workers from the operations of repetitive measurements entailing losses of time and, in the long run, leading to unavoidable mistakes.
Another purpose of the invention is to obtain a device to form the metallic cages for reinforcement purposes which will drastically reduce the spaces and bulk occupied in the plant, and which will require only the same working space as the size of the cage to be formed.
A further purpose of the invention is to obtain a method where the longitudinal rods, once they have been positioned, are not displaced throughout the whole process of forming the cage.
The invention arranges to position beforehand, by means of an automated procedure, all the longitudinal rods which will comprise the cage, correctly distanced transversely, already in correspondence with the specific horizontal planes in which those rods are substantially positioned according to the type of cage to be made.
These longitudinal rods are supported by suitably separated transverse supports, the number and distance apart of which depend on the length of the longitudinal rods involved and thus of the cage to be formed.
These supports may consist of a transverse rod, of a shelf or of analogous means performing the same function.
These supports can be displaced in relation to the vertical plane for the correct positioning of the longitudinal rods at the various heights according to the cage to be formed, and can be moved axially.
A structure is included above these supports for the longitudinal rods and bears a movable carriage, the movement of which the structure permits.
The stirrups which are to be progressively fixed to the longitudinal rods so as to form the cage are arranged on the carriage.
This movable carriage includes a supporting arm, which has the task of upholding at a suspended position, on their upper side or arc, the stirrups which have to be placed at suitable positions, separated lengthwise, for embodiment of the metallic cage.
As we said above, these stirrups can have any shape to suit the requirements.
In the method according to the invention, after the longitudinal rods have been positioned at the various heights defined by the position of the relative transverse supports, the movable carriage which upholds the stirrups begins to move on a plane which is substantially parallel to the horizontal plane of the longitudinal rods and causes the progressive positioning of the stirrups on the longitudinal rods, which remain fixed in their position.
As soon as the movable carriage reaches the position corresponding to the positioning of the first stirrup, which position can be determined according to the invention by a control program which manages the activation of the movable carriage, the carriage halts and thus enables the worker to remove the first stirrup from the supporting arm, to place that stirrup on the upper longitudinal rods and possibly to carry out the first welding or tying.
The movable carriage then moves again to the position corresponding to the position of the second stirrup and halts there, and the procedure of fixture of the stirrup to the rods is repeated.
This procedure is repeated for all the stirrups needed to complete the cage, normally the same number as the number of stirrups on the movable carriage.
It should be borne in mind that in this step the longitudinal rods of the upper level are arranged in the correct reference position, which can be adjusted at the start-up according to the subjective choice of the machine operator but which then remains constant at least for all the operations of welding the upper rods to the stirrups.
Instead, the rods of the lower levels are arranged in a position raised above their positioning on the stirrup; this enables the stirrups to be moved along the rods without contact and/or without problems of obstructions.
The stirrups are fed forwards at a position raised slightly above the upper longitudinal rods so as to make possible their passage without problems and so as not to create, at the same time, problems for the machine operators in the operations of moving and positioning of the stirrups themselves on those upper rods.
As the movable carriage carrying the stirrups gradually approaches a longitudinal position where the supports for the longitudinal rods are present, the supports are retracted and thus the movable carriage is able to pass.
When at least some of the welds or ties of the stirrups to the upper rods have been carried out, the supports which uphold the intermediate and/or lower rods are lowered so as to lay those intermediate and/or lower rods on the stirrup.
These rods, therefore, are already in the welding and/or tying position and are suitably separated from each other, and the worker involved needs to do nothing other than perform the welding and/or tying to the stirrup.
In this step, all the carriages which uphold the transverse supports and therefore the longitudinal rods, are advantageously raised, possibly in separate steps, to arrange those rods at the most suitable heights and to assist the operations of welding and/or tying according to the choice of the machine operator.
All the movements and positionings, both of the movable carriage which supports the stirrups and the carriages associated with the transverse rods which support the longitudinal rods, are managed by the device's control unit.
In this way, it is possible to program the movements and positionings according to the type of stirrup which is to be made, and it is possible to memorize and reproduce these movements and positionings of the stirrups and longitudinal rods every time a stirrup of the same type has to be made.
In this way, the manual work of the workers is substantially reduced to the unloading of the stirrups from the carriage and to the tying or welding of the longitudinal rods.
The attached figures are given as a non-restrictive example and show a preferred embodiment of the invention as follows:-

Fig.1: gives a perspective, diagrammatic view of the device which forms a metallic cage according to the invention;
Fig.2: is a partial side view of the device of Fig.1;
Fig.3: shows a partial frontal section of the device of Fig.2 along the line A-A.

A device 10 shown in Figs.1 to 3 has the purpose of producing metallic cages for reinforced concrete, the cages consisting of a plurality of longitudinal rods or round bars 11 connected by transverse stirrups 12 separated lengthwise.
In this case, the description refers to a closed metallic cage of a T-shaped type having three heights of positioning of the longitudinal rods 11 substantially in the corners within the transverse stirrups 12.
In this embodiment it is possible to define upper longitudinal rods 11a, intermediate longitudinal rods 11b and lower longitudinal rods 11c.
The device 10 can be used in the same way to produce cages having any desired shape such as polygonal, circular, trellis-shaped, etc.
All the longitudinal rods 11a, 11b and 11c required for production of the cage are positioned at the start of the cycle on supporting elements consisting in this case of transverse rods 13 and remain fixed in this position for the whole duration of the cage being formed.
The transverse rods 13 are arranged in groups which are separated lengthwise, each of the groups comprising a number of superimposed transverse rods 13, in this case three, corresponding to the number of horizontal planes, or levels, on which the longitudinal rods 11a, 11b and 11c are positioned.
These groups of tranverse rods 13 can easily be excluded from the device if it is required to obtain shorter cages or cages of a different shape.
In this example, the transverse rods 13 are arranged at supporting poles 20 spaced apart at a distance depending on the length, weight and section of the longitudinal rods 11a, 11b and 11c.
The distance between the supporting poles 20 is such as to ensure a balanced and secure support for the longitudinal rods 11a, 11b and 11c, even when a group of transverse rods 13 is retracted and the rods 11a, 11b and 11c are supported only by the groups of transverse rods 13 which are arranged respectively upstream and downstream of the said retracted group.
These transverse rods 13 are associated, for each supporting pole 20, with carriages 14, respectively 14a, 14b and 14c, providing vertical displacement; these vertically movable carriages 14 make it possible to position, at the required heights, the transverse rods 13 upwards (15a) or downwards (15b), according to the type of cage which is to be formed and the type of stirrup used.
The positioning of the carriages 14, in this case, is automated and governed by a control unit 30 in order to define automatically the position of the longitudinal rods 11a, 11b, and 11c according to the type of cage which is to be made.
Moreover, the transverse rods 13 can be retracted in the direction 16 so that they can be brought beyond the inner longitudinal rod 11 nearest to the supporting pole 20 at the position 13a.
To be more exact, in this case, on each carriage 14a, 14b and 14c there are means 31, associated with the relative transverse rod 13, which cause it to be axially displaced, possibly following instructions from the control unit 30.
The device 10 also comprises above the upper longitudinal rods 11a a supporting and displacement structure 17 for the movable carriage 18.
The supporting and displacement structure 17 may comprise rails, guides, supports or anything else necessary according to the type, conformation and size of the movable carriage 18.
In this case, the movable carriage 18 is mounted projecting over the supporting and displacement structure 17.
The movable carriage 18 is suitable to move on a plane substantially parallel to, and above, the plane of positioning of the upper longitudinal rods 11a.
In this case, the movable carriage 18 includes a supporting arm 19, on which are loaded in a suspended position with their upper side rested on the supporting arm 19 at least most of the stirrups 12 required for production of the metallic cage.
The supporting arm 19 is positioned at a height slightly higher than the horizontal plane defined by the upper longitudinal rods 11a.
At the start of the cycle, the machine operator pre-sets the type of cage or trellis to be made in the control unit 30.
According to this setting, the control unit 30 determines the correct position which must be assumed by the carriages 14, particularly the carriages 14a associated with the upper longitudinal rods 11a, according to the type of cage to be made and/or any particular requirements of the specific machine operator, in order to ensure the most suitable working conditions for the worker who will have to perform the welding and tying.
Carriages 14b and 14c assume a position which is coordinated with that of the carriages 14a according to the conformation of the cage to be produced.
At this point, the movable carriage 18 is taken to a position at the head of the device 10 and all the longitudinal rods 11 are positioned on the relative transverse rods 13.
Then the movable carriage 18 advances and thus causes the progressive positioning of the stirrups 12 between the longitudinal rods 11.
When the movable carriage 18 reaches the pre-determined position corresponding to the placement of the first stirrup 12, the control unit 30 causes it to stop.
The stirrup 12 is removed by the movable arm 19 and rested on the upper longitudinal rods 11a; at this step the machine operator may perform the tying or welding of the stirrup 12.
The movable carriage 18 is then made to start again until it reaches the next position for the placement of the stirrup 12.
As the movable carriage 18 meets the transverse rods 13, the latter 13 are retracted to the position 13a to avoid contact with the stirrups 12.
This procedure is repeated until all the stirrups 12 have been placed in the pre-determined position with respect to the longitudinal rods 11.
According to a variant of the invention shown in Fig. 2, transverse rods 113 providing at least momentary support are included and are solidly fixed to the movable carriage 18 advantageously at a front position in the direction of advance of the carriage 18 and below the carriage 18.
These transverse rods 113 have the purpose of supporting the upper longitudinal rods 11a when the transverse rods 13 are retracted to allow the movable carriage 18 with the stirrups 12 to pass.
In fact, in this situation of retraction of the transverse rods 13 the distance between the supporting poles 20 may be such that an effective support of the longitudinal rods 11 may be lacking when those rods 11 are further burdened by the presence of the stirrups 12 already discharged at a time when the intermediate support is lacking.
The inclusion of these transverse rods 113 which advance together with the movable carriage 18 enables the interspace between two supporting poles 20 not to be reduced, for such a reduction would entail complications in the cycle and the slowing and reduction of the output of the device.
The upper longitudinal rods 11a are positioned at a height which substantially corresponds to the correct reference height of the metallic cage, whereas the intermediate rods 11b and lower rods 11c are kept slightly raised above the corresponding sides of the stirrups 12 so as not to cause interference with the forward movement of the stirrups 12.
According to a variant, when at least most of the stirrups 12 have been unloaded onto the upper longitudinal rods 11a and have been solidly secured thereto, the control unit 30 causes lowering of the carriages 14b and/or 14c associated with the transverse rods 13 supporting the intermediate longitudinal rods 11b and lower longitudinal rods 11c.
In this way, those rods 11b, 11c are rested on the inner sides of the stirrups 12 already positioned.
Then, all the carriages 14a, 14b, 14c are advantageously raised, possibly in separate steps, so as to bring the intermediate rods 11b and lower rods 11c to an easier position for performing all the necessary steps of welding or tying to complete the production of the cage.

Claims

Method for the production of trellises or metallic cages for reinforced concrete, the cages consisting of a plurality of longitudinal rods (11a, 11b, 11c) connected to transverse stirrups (12) suitably separated lengthwise, whereby the longitudinal rods (11a, 11b, 11c) are positioned in the cage at at least two different heights and are supported by transverse support elements (13) supported by carriages (14a, 14b, 14c) at least movable vertically, the stirrups (12) being able to have any shape such as a polygonal, circular, T-shaped or other shape, there being included a control unit (30), the method being characterised in that it includes the following operational steps:
- the conformation of the cage is pre-set by the control unit (30);

- at least the upper carriages (14a), to define the maximum working level according to the conformation of the cage, are positioned;

- the intermediate carriages (14b) and/or the lower carriages (14c) are positioned, this positioning being functionally correlated to the positioning of the upper carriages (14a);

- the longitudinal rods (11a, 11b, 11c) are positioned at the different heights on transverse supporting elements (13) associated with the carriages (14a, 14b, 14c);

- a movable carriage (18) is positioned which supports at least the desired number of stirrups (12) in cooperation with a position substantially at the leading end of the longitudinal rods (11a, 11b, 11c);

- the movable carriage (18) advances to the position where the first stirrup (12) is placed;

- the movable carriage (18) halts and the first stirrup (12) is removed by the operator from the movable carriage (18), positioned on the upper longitudinal rods (11a) and at least welding or tying is performed;

- the movable carriage (18) restarts and reaches the placement position of the second stirrup (12), the operator fixes the stirrup (12) to the upper longitudinal rods (11a), and so on for the other stirrups (12),
this method including moreover the retraction of the transverse support elements (13) when there is a condition of interference with the advance of the movable carriage (18).
Method as in Claim 1, in which in the initial prearrangement step the carriages (14b, 14c) associated with the transverse elements (13) which support the intermediate (11b) and lower (11c) longitudinal rods are located vertically in a position at least slightly raised above the horizontal planes defined by the inner sides of the stirrups (12).
Method as in Claim 1 or 2, in which, when at least part of the stirrups (12) have been tied or welded to the relative upper longitudinal rods (11a), the intermediate (14b) and/or lower (14c) carriages are lowered to rest the relative intermediate (11b) and/or lower (11c) rods on the inner sides of the stirrup (12).
Device to produce trellises or metallic cages for reinforced concrete, the cages consisting of a plurality of longitudinal rods (11a, 11b, 11c) connected to transverse stirrups (12) suitably separated lengthwise, the longitudinal rods (11a, 11b, 11c) being arranged in the cage at at least two different heights, the stirrups (12) being able to have any desired shape such as a polygonal, circular, T-shaped or other shape, the device being characterised in that it comprises:
- a plurality of transverse supporting elements (13), which are associated with the relative carriages (14a, 14b, 14c) movable at least vertically, to support the longitudinal rods (11), the transverse supporting elements (13) being vertically separated and defining groups of transverse support elements (13) spaced lengthwise, each of these transverse support elements (13) being axially movable,

- a supporting and displacement structure (17) for a movable carriage (18), the structure (17) being located on a plane parallel and above the plane of positioning of the longitudinal rods (11), the movable carriage (18) including at least one supporting arm (19) suitable to uphold in a suspended position a plurality of stirrups (12), the movable carriage (18) being suitable to be displaced on the parallel plane above the upper plane of positioning of the longitudinal rods (11) and to stop around the longitudinal position where the stirrup (12) is placed on the longitudinal rods (11);

- a control unit (30) which manages at least the movement of the movable carriage (18) during the step when the stirrups (12) are positioned on the longitudinal rods (11).
Device as in Claim 4, in which the control unit (30) manages at least also the vertical positioning of the carriages (14a, 14b, 14c) during the initial pre-arrangement step.
Device as in Claim 4 or 5, in which the control unit (30) manages at least also the retraction of the transverse elements (13) when there is a condition of interference with the advance of the movable carriage (18).
Device as in any Claim from 4 to 6 inclusive, in which the transverse supporting elements (13) have an extended supporting position (13) and a retracted position (13a) which is functionally connected to the passage of the movable carriage (18).
Device as in Claim 7, which includes means (31) to axially displace the transverse support elements (13), these means (31) being associated with the relative carriage (14a, 14b, 14c) to vertically position the transverse support elements (13).
Device as in any of Claims 4 to 8 inclusive, in which the movable carriage (18) includes transverse supporting means (113) for the temporal support of the upper longitudinal rods (11a), the means (113) being solidly fixed to the carriage (18) and cooperating at the lower part with the plane of positioning of the upper longitudinal rods (11a).