FR2811001A1 - Layer of bars for making pre-stressed concrete slabs comprises flexible strips which are looped around each bar and sewn together - Google Patents

Abstract

The layer comprises bars (1-4) able to be coated with concrete, two flexible strips (5,6) and means (7) for joining the flexible strips with each bar. The joining is constituted by the fact that each flexible strip surrounds each bar to form loops (8-11) around the bars and by sewing (12) together the two ends (13,14) of each loop so that each loop completely surrounds its associated bar. An Independent claim is included for a machine making the layer of bars.

Description

l

  TABLECLOTH FOR USE, FOR EXAMPLE,

  OF A PRE-STRESSED CONCRETE SLAB OR THE LIKE, AND

  MACHINE FOR MAKING SUCH A TABLECLOTH

BARS

  The present invention relates to the plies of bars intended for the production, for example, prestressed slabs of concrete or the like. The present invention relates to

  also the machines for making these layers of bars.

  When you want to make a concrete slab by inserting reinforcing bars subject to stresses, for example to make entablatures of bridges, terraces, etc., you first form a formwork of the external form of the slab that must be obtained, we then tend on this formwork steel cables on which there is a welded mesh to take up the forces of the slab perpendicular to the cables, then, while keeping the steel cables under stress, we pour the fresh concrete in

  the formwork by flooding the cables and the trellis.

  The concrete is then left to crystallize or dry, always maintaining the stresses on the cables, until it takes its solid form. This technique well

  known in itself will not be described more fully here.

  To make this type of slab, so far, the wire mesh is brought on site, then the technicians, for example the formworkers, arrange them in the formwork

  next to each other by pinning them to the stretched cables.

  This technique gives good results, but it requires relatively long manual operations which undoubtedly contribute to the increase in

  cost of manufacturing such slabs.

  The object of the present invention is therefore to produce a strip of bars intended to largely overcome the drawbacks mentioned above of trellises.

  welded metal of the prior art.

  The present invention also aims to produce a machine for producing the plies of bars according to the invention. More specifically, the subject of the present invention is a sheet of bars intended for example for the production of a prestressed slab reinforcement in concrete or the like, characterized in that it comprises: - at least two bars capable of being coated with concrete, - at least two flexible bands, and - means for joining the two flexible bands with each bar so that the two bars can be substantially parallel to one another and at a distance

determined from each other.

  The present invention also relates to a machine for producing a sheet of bars as defined above, characterized in that it comprises - a support plate, - a presser foot, - means for moving the presser foot between two positions, a first position in which it is distant from the support plate to define a space between it and this support plate, said space having a thickness at least equal to the sum of the thickness of a bar and two thicknesses of a flexible strip and comprising an opening allowing access to the interior, and a second position in which the presser foot is capable of coming into contact with the support plate, - means for joining two portions of flexible strip together, - means to maintain a flexible strip without being subjected to a tensile force, in front of and near said opening of said space, and - first means for gripping a bar capable of taking e and maintain said bar, to bring it against the face of the flexible strip opposite to that which is opposite the opening of said space, and to introduce it into said space beyond the presser foot in

  entraining with it said flexible strip.

  Other characteristics and advantages of the invention will become apparent during the

  following description given with reference to the accompanying drawings by way of illustration but not at all

  limiting, in which: FIG. 1 represents a cross section of a sheet of bars according to the invention, FIG. 2 represents, in perspective view, part of the sheet of bars according to FIG. 1, FIG. 3 represents, under schematic form, an embodiment of the machine according to the invention making it possible to produce a ply of bars according to FIGS. 1 and 2, and FIG. 4 represents a detail of the machine according to FIG. 3, allowing

to explain how it works.

  It is specified that, on all four figures attached to this

  description, the same references designate the same elements, whatever the figure

  on which they appear and whatever the form of representation of these elements. Similarly, if elements are not specifically referenced in one of the figures, their references can be easily found by referring to another figure. It is also specified that, when, according to the definition of the invention, the object of the invention comprises at least one element having a given function, the mode of

  embodiment described may include several of these elements.

  Similarly, if the embodiment of the object according to the invention as illustrated

  contains several elements of identical function and if, in the description, it is not

  specified that the object according to this invention must necessarily include a particular number of these elements, the object of the invention may be defined as comprising "at

minus "one of these.

  Figures 1 and 2 show a sheet of bars N according to the invention which, in an advantageous application, is intended for the production of a reinforcement, for example, of a prestressed concrete slab or the like in order to take up the forces perpendicular to the cables providing the prestress. The sheet N comprises at least two bars 1, 2, 3, 4, ..., at least two flexible strips 5, 6 of any flexible material, for example in a texture such as fabric of textile fibers, plastics, etc. , and means 7 for joining the two flexible strips with each bar so that the bars can be substantially parallel to one another and at a determined distance from each other. In an advantageous embodiment, the means 7 for joining the two flexible bands 5, 6 with each bar 1, 2, 3, 4, ... are constituted by the fact that each flexible band surrounds each bar to form loops 8 , 9, 10, 11, ... around these bars respectively, these loops being spaced a distance "L" equal to the

  determined inter-axis distance planned to separate the bars.

  These means 7 further comprise means 12 for securing together the two ends 13, 14 of each loop 8-11 so that each loop surrounds

  completely the bar with which it is associated.

  These securing means 12 can be formed in several ways, for example by means of a weld when the strip is made of a material capable of being welded, for example a wire mesh, plastic, etc. However, in an advantageous embodiment, these securing means 12

  are, as more particularly illustrated in FIG. 2, constituted by a seam 15.

  The advantages of a strip of bars as described above are manifold.

  First of all, such a sheet can be produced automatically, in the factory, then easily transported with a minimum of space since it can be

rolled up on itself.

  After receiving it at the installation site, the formworkers unroll the sheet N, easily cut the flexible strips to obtain a sheet having the desired number of bars, then extend it in the formwork, if necessary by joining the free ends of the flexible strips with the edges of the formwork to ensure that the sheet is well maintained

  during the pouring of the concrete and its drying.

  As mentioned above, the present invention also relates to a machine M making it possible to produce a sheet of bars N as described above, more particularly in the case where the means 12 for securing the two ends of the

  mouths 8-11 are constituted by a seam 15.

  FIG. 3 represents, in diagrammatic form, a preferred embodiment of a machine M making it possible to automatically produce such a ply N comprising at least two bars connected by at least two flexible bands, each band forming around each bar a loop of which the ends are sewn together. FIG. 4 represents a detail of the machine M. The machine M schematically represented in FIGS. 3 and 4 essentially comprises a support plate 20, a presser foot 21 and means 22 making it possible to move the presser foot 21 between at least two positions, a first position in which the presser foot is distant from the support plate 20 to define a space 23 whose thickness is at least equal to the sum of the thickness of a bar and two thicknesses of a flexible strip (FIG. 3 ), and a second position in which the presser foot 21

  is able to come into contact with the support plate 20 (Figure 4).

  In addition, when the presser foot 21 is in its first position, it delimits a

  opening 24 allowing access to the interior of space 23.

  The machine M also comprises, associated with the presser foot 21, means 25 capable of joining together two portions of flexible strip, for example the two ends 13, 14 of the loops 8-11 defined previously. These means can be of any type, for example welding means if the strip 5, 6 is a flexible metallic strip, for example a metallic braid, or even a strip made of a plastic material.

or the like.

  However, in a particularly advantageous embodiment, these means are constituted by means making it possible to sew two portions of the flexible strip 5, 6 one on the other when this strip is for example a textile strip or a

  braid of any other material, for example polyester.

  These means 25 making it possible to sew, such as those illustrated on the

  Figures 3 and 4 will not be described more fully here because they are well known in themselves.

  same and are comparable to the means for making a seam such as those which are known in sewing machines and which schematically comprise a needle, a needle clamp, a bobbin in its housing, a spool of sewing thread, etc. However, it is specified that these sewing means 25 are advantageously those whose needle moves in X and Y relative to the support plate 20 so as to carry out a sewing with stitches known for example under the term of "zigzag stitches" "or a

"button pose".

  The machine M also comprises means 26 for holding a flexible strip, 6 without being subjected to a tensile force, in front of and near the opening

  24 of the space 23 defined above, and of the first gripping means 27 of a bar 1-

  4 able to take and hold a bar, to bring it against the face 28 of the strip 5, 6

  opposite to that facing the opening 24, and to introduce it into the space 23 above

beyond the presser foot 21.

  In an advantageous embodiment, these holding means 26 of the flexible strip consist of a supply reel 30 carrying a certain length of flexible strip wound on it and a receiving drum 31 which, as explained below during the

  description of the operation of the machine, is suitable for receiving the sheet of bars

  performed. The receiving drum 31 is rotated for example by a motor

  controllable 32 whose output shaft is connected to the axis of the drum.

  Preferably, these means 26 further comprise guides 33 which make it possible to maintain the flexible strip as defined above in front of the opening 24 of

space 23.

  They also advantageously comprise second controllable gripping means 34 capable of receiving the bar after the flexible strip has been sewn by forming a loop around it. By way of example, these second controllable gripping means 34 are constituted, as illustrated, by two jaws forming a clamp 36 mounted on a carriage 37, itself slidingly mounted on a slide 38 and controlled in translation by means 39 of the jack type or similar. The clamp 36, the carriage 37 and the slide 38 are positioned and arranged with respect to the support plate 20, the presser foot 21 and the receiving drum 31 so that, on the one hand, the clamp can move between substantially the opening 24 of space 23 and the receiving drum 31, and on the other hand that it can be stopped at a determined adjustable distance from the opening

  24, for example at a distance equal to the distance "L" defined above.

  The first gripping means 27 are advantageously constituted by an arm 40, one end 41 of which is terminated by gripper means 42 of the jaw type and the other end 43 of which is pivotally mounted about an axis 44. They further comprise means 45 for controlling the rotation of the arm 40 about the axis 44 between at least two positions, a first position like that illustrated in FIG. 3 in which the clamp means 42 are able to receive a bar, and a second position in which the bar is located in the space 23 beyond the presser foot 21 after it has been in contact with the face 28 of the flexible strip 5, 6 to drive it with it in the space 23, so that the bar surrounded by the flexible strip takes a position by

  relative to the presser foot and to the support plate 20 as illustrated in FIG. 4.

  The means 45 for controlling the rotation of the arm 40 are for example constituted by a jack 46 whose output rod 47 cooperates with a drum 48 of axis secured to the axis of rotation 44 of the arm, the rod 47 and the drum 48 being shaped as a rack. As for the two first and second positions of the arm 40, they are respectively defined by two advantageously adjustable stops 49, 50, the stop 49

  defining the first position, the stop 50 defining the second.

  Advantageously, the machine M has a reserve 51 of bars 1-4 located in the high position of the machine. This reserve comprises for example an inclined ramp 52 terminated by a chute 53 comprising in the lower part 54 a controllable door 55

  to deliver the bars one by one.

  Of course, to control all of the operations performed by the machine M as described below, the machine includes a control member 60 whose outputs AG are respectively connected to the control inputs A'-G 'respectively of the reserve of bars 51, of the jack 46 controlling the rotation of the arm 40, means 22 and 25 for moving the presser foot and for securing two parts of a flexible strip, namely the sewing means in the case of the embodiment according to the figures 3 and 4, means 39 for translational control of the carriage 37, of the motor 32

  rotating the receiving drum 31, gripper means 42 and gripper 36.

  Of course all the means described above constituting the machine according to the invention is mounted in cooperation, for example, with a frame 100 which can take

  multiple forms, in particular that illustrated in FIG. 3.

  The machine M described above operates in the following manner, it being specified that

  this operation will be described with reference to FIGS. 3 and 4.

  The machine is first of all in the configuration illustrated in FIG. 3. The flexible strip 5, 6 is unwound from the supply reel 30 until its winding o10 on the receiving drum 31 is primed, passing through the guides 33 and opposite the opening 24 of the space 23, the presser foot 21 being in its first position remote from the support plate 20, the arm 40 being in its first position, the

  clamp means 42 being in the open position facing the door 55.

  The opening of the door 55 is controlled from the control input A 'by means of the control member 60. The bar 1-4 in the lower part of the inclined ramp 52 falls by gravity into the clamp means 42 which close to hold it firmly following an order signal issued at the output F of the control member 60 and applied to their control input F. An order issued at the output B of the control member 60 and applied to the control input B ′ of the jack 46 controls the rotation of the arm 40 so as to pass it from its first position to its second position by following the path indicated by the arrow 70. In this movement of rotation of the arm 40, the bar held by the clamp means 42 is

  present opposite the opening 24 in front of which the flexible strip 5, 6 is already located.

  By entering the space 23 to beyond the presser foot 21, the bar causes the

  flexible strip which thus forms a loop around it as illustrated in FIG. 4.

  The control member then issues a control command at its output C which, applied to the input C ′, controls on the one hand the passage of the presser foot from its first position (FIG. 3) to its second position (FIG. 4 ) by pinching the two ends 13, 14 of the loop, and on the other hand, possibly after a slight time constant, the sewing means 25 for sewing 15 (FIG. 2) of these two ends of the

loop over each other.

  When this operation is finished, the control member 60 delivers to its outputs D, E, F and G, command signals which are respectively applied to the control inputs D ', E', F 'and G' so that the machine performs the following operations: the jack 39 brings the clamp 36 into its open position around the bar 1-4 then the clamp 36 is tightened on the bar, the arm 40 is brought back to its first position to take another bar, the gripper means 42 are open and the presser foot 21 returns to its first position. Under the thrust exerted by the jack 39 on the carriage 37, the bar surrounded by the flexible band loop leaves the space 23, and the clamp 36 with the bar is brought to a distance from the opening 24 in the space 23 substantially equal to the distance "L", the clamp still firmly holding the bar surrounded by the flexible band loop. The receiving drum 31 is driven simultaneously in rotation by the motor 32 and winds the web. The arm 40 is brought into its second position as described above with a new bar, and another flexible band loop is sewn around this new bar.

  All of these operations can be repeated as many times as necessary.

  The machine M described above makes it possible to connect a plurality of bars 14 with a flexible strip 5, 6. However, since the sheet must include at least two flexible strips, and even advantageously more than two, the device making it possible to produce a sheet of bars with "n" flexible bands will consist of "n" identical M machines positioned one beside the other, the inclined ramps 52 being parallel and located without a single plane so that each bar in reserve can be grasped simultaneously by all the clamp means 42 and that the operations described above can be

  performed simultaneously by the "n" machines.

  To this end, the operation of the "n" machines M will be synchronized thanks to their control members, the synchronization inputs 61 of which will be connected to each other.

known way.

  In this case, each machine has its own receiving drum, or only one

  drum receiver is common to all machines.

  It is furthermore clearly specified that the loops surround the bars relatively freely while keeping them parallel and at a determined distance from one another, so as to allow these bars to slide when they are stressed. Indeed, if the stopper 49 allows the arm 40 to be positioned correctly so that the clamp means 42 can firmly grip the bars, the stopper 50 allows

  to adjust the second position of this arm and therefore the length of the loops.

Claims (16)

  1. Tablecloth of bars intended for example for the production of a prestressed slab reinforcement in concrete or the like, characterized in that it comprises: - at least two bars (1-4) capable of being coated with concrete, at at least two flexible bands (5, 6), and - means (7) for joining the two flexible bands with each bar so that the two bars can be substantially parallel to one another at a distance determined from each other.   2. Bar sheet according to Claim 1, characterized in that the   means (7) for joining the two flexible strips (5, 6) with each bar (14) consist of the fact that each flexible strip surrounds each bar to form loops (8-11) around these bars respectively and by means (12) for securing together the two ends (13, 14) of each loop (8-11) so that   each loop completely surrounds the bar with which it is associated.   3. Bar sheet according to Claim 2, characterized in that the   securing means (12) consist of at least one seam (15).   4. Bar sheet according to one of Claims 1 to 3, characterized by   the fact that said flexible strips consist of at least one of the textures   following: fabric of textile fibers, plastics, metallic braid, plastic.   5. Machine for producing a sheet of bars according to one of the   Claims 2 to 4, characterized in that it comprises   - a support plate (20), - a presser foot (21), - means (22) for moving the presser foot (21) between two positions, a first position in which it is distant from the support plate (20) to define a space (23) between it and the support plate, said space having a thickness at least equal to the sum of the thickness of a bar (1-4) and two thicknesses of a flexible strip (5, 6) and comprising an opening (24) allowing access to the interior, and a second position in which the presser foot (21) is able to come into contact with the support plate (20)   -means (25) for securing together two portions of flexible strip, - means (26) for holding a flexible strip (5, 6) without it being subjected to a tensile force, in front of and near said opening (24) of said space (23), and - first gripping means (27) of a bar (1-4) able to take and hold said bar, to bring it against the face (28) of the strip flexible (5, 6) opposite to that which is opposite the opening (24) of said space (23), and to introduce it into said   space beyond the presser foot (21) by driving said flexible strip with it.   6. Machine according to Claim 5, characterized in that the holding means (26) of the flexible strip comprise a supply reel (30) carrying a certain length of flexible strip wound on it and a receiving drum (31) capable of   receive the sheet of bars once made.   7. Machine according to Claim 6, characterized in that said receiving drum (31) is rotated by a controllable motor (32) of which   the output shaft is connected to the axis of the drum.   8. Machine according to one of Claims 6 and 7, characterized in that   that said holding means (26) further comprise guides (33) making it possible to   hold the flexible strip in front of the opening (24) of the space (23).   9. Machine according to one of Claims 6 to 8, characterized in that   that said holding means (26) further comprises second controllable gripping means (34) capable of receiving the bar (1-4) after the flexible strip   (5, 6) has been sewn by forming a loop around said bar.   10. Machine according to Claim 9, characterized in that said second controllable gripping means (34) are constituted by two jaws forming a clamp (36) mounted on a carriage (37) mounted to slide on a slide (38) and controlled by translation by jack means (39), the clamp (36), the carriage (37) and the slide (38) being positioned and arranged with respect to said support plate (20), to the presser foot (21) and to the receiving drum (31) so that the clamp moves between   substantially the opening (24) of the space (23) and the receiving drum (31).   11. Machine according to one of Claims 6 to 10, characterized in that   that said first gripping means (27) consist of an arm (40) one end of which (41) is terminated by clamp means (42) and the other end of which (43) is pivotally mounted about an axis (44), means (45) for controlling the rotation of said arm (40) about said axis of rotation (44) between at least two positions, a first position in which the clamp means (42) are capable of receiving a   bar (1-4), and a second position in which the bar is located in the space (23) above   beyond the presser foot (21) after being brought against the face (28) of the flexible strip   (5, 6) opposite to that which is opposite the opening (24) of said space (23).   12. Machine according to Claim 11, characterized in that the means (45) for controlling the rotation of the arm (40) consist of a jack (46) whose output rod (47) cooperates with a drum (48) axis secured to the axis of rotation (44) of said arm (40), the rod (47) and the drum (48) being shaped rack.   13. Machine according to one of Claims 11 and 12, characterized in that   that it includes stop means defining the first and second positions of the arm (40).   14. Machine according to one of Claims 5 to 13, characterized in that   that it comprises a reserve (51) of bars (1-4), said reserve being located in the high position and comprising an inclined ramp (52) terminated by a chute (53) comprising in the lower part (54) a controllable door ( 55) for delivering said bars (1-4) one by one, said first gripping means (27) being able to receive each bar   delivered in the lower part (54) of said chute (53).   15. Machine according to one of Claims 5 to 14, characterized in that   that said means (25) capable of joining two flexible strip portions together consist of means making it possible to sew the two strip portions flexible one over the other.   16. Machine according to Claims 5 to 14, characterized in that it   comprises a control member (60) whose outputs (A-G) are respectively connected   at the control inputs (A'-G ') respectively bars reserve means (51-   A '), actuator means (46-B') for controlling the rotation of the arm (40), means (22) for moving the presser foot and securing means (25-C '), actuator means (39-D '), of the motor for controlling the rotation of the receiving drum (32-E'), means for gripping the first gripping means (42-F ') and means for gripping the   second gripping means (36-G ').