METHOD AND APPARATUS FOR COATING PIPES

Description

[0001] This invention is concerned with coating of pipes of the type used in subterranean or submerged pipelines for recovery of oil, gas, slurries or the like pipeable materials from a subterranean well. In particular it is concerned with pipes in which a steel pipe section is coated with an anti-corrosion coating and then a concrete aggregate antibuoyancy coating (hereinafter concrete coating). Such pipes normally include a mechanical shear transfer device in the form of wire windings or caging applied around the anti-corrosion coating prior to application of the concrete coating. This opposes the tendency of the concrete coating to slip or jump off the anti-corrosion coated pipe during laying operations which can impose considerable bending stresses upon the pipe.

[0002] Reference may be made to the following patents Us 3 955 600 and GB 1 504 051/2 which are representative of the known art.

[0003] Typically, each pipe section is caused to rotate about its longitudinal axis and passed longitudinally past a concrete coating station wherein concrete/aggregate is caused to impinge upon the rotating pipe thereby building up a thickness of concrete on the pipe to form a coating. Normally where a wire mesh (hereinafter referred to as wire) winding is used, it is necessary to lash an end of the wire to the front end of the pipe before it is rotated and advanced past the concrete coating station. As the pipe is so advanced, the wire is fed in a continuous manner at an appropriate angle to allow the rotation of the pipe to cause winding of wire throughout its length. Once that section has passed by that station, the wire must be cut and lashed at the tail end of the pipe section. This has several disadvantages which include a less than desirable rate of production because of the need to stop the pipe before and after the concrete coating station to secure the wire which would otherwise simply exhibit a "clock-spring effect" and release itself, during coating, to a loose non-uniform relaxed winding without the desired function. Further, the process cannot readily be automated due to the need to have personnel attending to fastening of the wire at both ends of the pipe. Additionally it is undesirable to have a free end of wire directly contacting the anti-corrosion coating on the steel pipe since it is liable to penetrate that coating through abrasive contact and cause corrosion attack points which could weaken and ultimately cause premature failure and the need for replacement of that section.

[0004] Therefore it is an object of this invention to obviate or mitigate the aforementioned disadvantages by providing a coating method and apparatus for carrying out the method offering several advantages over the known art including the capability of improving production rate, allowing the possibility of automating the coating station, reducing the personnel demands and minimising wire contact with the anti-corrosion coating.

[0005] Accordingly this invention provides in its broadest aspect a method of coating pipe sections which comprises conveying a series of pipe sections past a concrete coating station having means for advancing and rotating the sections longitudinally, characterised by providing at that station means for continuously feeding a line to the rotating sections, means for continually feeding a wire to the rotating sections in a manner such that the line fed to the sections brings the wire into position for winding around the section and overlies the wound wire throughout its length, and cutter means, cooperating with the wire-feed means, for automatically cutting the wire at predetermined time intervals whereby in carrying out the method, the line is first fed to the leading end of the rotating pipe and wound around same for sufficient turns to secure same, then wire is drawn in to begin the winding around the pipe during the application of concrete coating in the station, and the wire is subsequently cut as it is fed to prevent the winding extending beyond the concrete coated length of the pipe section whilst the line continues to be wound around the tail end of the pipe.

[0006] Thus the objects of the invention are achieved in that the line acts to secure the front and tail ends of the wire winding to avoid the need to manually lash the wire to the pipe, wire cutting is achieved automatically without the need to stop the advance of the pipe sections and the method readily lends itself to automation whereby the feed rate of wire together with the cutting intervals may be calculated and the station set to repeatedly wind wire within the concrete coating step. This has the advantage that the wire follows in the line during the initial stage of concrete coating whereby the wire itself never actually contacts the pipe section but becomes embedded within the concrete accumulating upon the pipe to form the weight coating.

[0007] Preferably, the method includes the provision of wire shaping means to allow pre-shaping of the wire to introduce curvature enabling the wire to readily conform to the circumference of the pipe section. This facilitates winding and allows the use of inexpensive line since it requires less force to secure the wire on to the pipe so that it is possible to use a variety of synthetic fibre or relatively fine wire filaments for this purpose.

[0008] Advantageously, each pipe section is conveyed away from the coating station at an accelerated rate in comparison with the throughput rate at the coating station whereby the line is snapped between sections.

[0009] The apparatus to be included in a station for coating rotating pipe sections with concrete according to this invention comprises a first feed mechanism for delivering a line from an appropriate renewable supply of same sufficient to obtain a substantially continuous feed of wire to the pipes to be coated at that station; a second feed mechanism located in close proximity to the first and arranged to feed wire from an appropriate renewable supply of same sufficient to secure a continual feed of wire in a manner such that it comes into contact with the line whereby it is subsequently caused to contact and form a winding around the rotating pipe section as concrete is applied thereto; and a cutter assembly for limiting the length of wire to be wound around the pipe section.

[0010] The cutter assembly may be a guillotine arrangement.

[0011] Preferably the wire feed mechanism cooperates with wire shaping means which preforms the wire in a curved configuration sympathetic to the circumference of the pipe.

[0012] Preferably also, the first feed mechanism comprises a plurality of rollers mounted in series through which the line is passed in a serpentine manner and at least one of said rollers is movable relative to the others to increase or decrease tension applied to the line.

[0013] The second feed mechanism preferably comprises a pair of counter-rotating rollers mounted in parallel and mutually spaced apart so as to allow contiguous passage of wire therebetween, at least one of which is driven by a motor to provide a means of advancing wire through the feed mechanism; a further pair of cooperating counter-rotating rollers having cutting elements on the surfaces thereof enabling wire passing between the rollers to be cut between the cutting elements at predetermined intervals; and a plurality of rollers located such that there is provided at least one reaction surface below the advancing wire against which the wire may be formed into a curved shape by controlled pressure exerted from at least one further roller located on the other side of the wire.

[0014] At least one roller in each pair may be provided with means for adjusting mutual spacing of the paired rollers to accomodate different thicknesses of wire and alter the pressure applied by the rollers.

[0015] It is preferred that the rollers are driven through chain and sprocket transmission by electric motors. In the case of the cutter roller drive it is necessary to include a clutch to disengage these rollers during winding of wire over the length of the pipe section and limit cutting operations to shortly before complete winding of wire over the pipe section. Also, in the case of the cutter rollers at least, it is preferred that the drive to one roller is transmitted to the other through engagement of gears at the ends of the rollers in order to synchronise the operation of the cutting elements thereon. The cutting elements are preferably formed and arranged on the roller surfaces so as to provide a guillotine cutting action.

[0016] The invention will now be further described by way of example with reference to the accompanying drawings in which:-

Fig. 1 is a schematic side elevational view of the apparatus for winding wire on a pipe at a concrete coating station omitting drive transmission and support structure for ease of identification of major components of the feed mechanisms;

Fig. 2 is a plan view of the apparatus showing detail of drive mechanisms for the apparatus;

Fig. 3 is a schematic view of one end of a pipe coated in accordance with the method of the invention; and

Fig. 4 is a plan view of a section of the wire mesh which may be applied by the method of the invention.

[0017] Referring primarily to Figs. 1 and 2 of the drawings, a wire winding apparatus will now be described for use at a station for coating pipe sections (1) which have already received an anti-corrosion coating (such as an epoxy resin) with concrete, in which said sections are fed in series past a concrete throwing device (not shown) on a driven roller conveyor device illustrated schematically only by the rollers (2). Above the said throwing device there is located a wire mesh spool and a nylon line spool neither of which is illustrated since their precise location is not important. A line feed mechanism including a plurality of rollers (4) at least some of which are movable relative to each other to enable control of tension in a line (3) is situated above the intended path of the pipes and feeds line (3) to the side of the pipes opposite to the concrete throwing device. Adjacent to the line feed mechanism is a wire feed mechanism comprising a pair of rubber coated rollers (6) mounted in parallel and driven in a counter rotary fashion by an electric motor (26) through a transmission including drive chain (27) and gears (28). The rollers are provided with adjuster screw means (29) for moving the rollers together or apart to adjust the pressure exerted upon wire passing between them and to accomodate differing thicknesses of wire. The wire feed mechanism is intended to provide a continual delivery of sections of wire of a length appropriate to provide a winding around a pipe section which is wholly confined within the concrete coating applied to the pipe. To this end there is a roller cutter assembly in the wire feed mechanism directly in the path of the wire (5) as it exits from the driven rollers (6). This cutter assembly comprises a pair of rollers (7) each having a cutter blade (8) extending longitudinally across the roller surface. These rollers are mounted in parallel and driven by an electric motor (46) through a coupling (47) and gears (48) providing for counter-rotation of the rollers (7). The cutter drive incorporates a clutch (49) enabling the cutter assembly to be disengaged to allow free passage of a length of wire between the rollers (7).

[0018] This embodiment also includes in the wire feed mechanism a wire forming assembly comprising a plurality of rollers (9, 10, 11, 12), two of which (11, 12) are mounted as a pair in parallel and driven by electric motor (36) through chain (37) and gears (39) counter to each other to cause advancement of wire between them. The other two rollers (9, 12) are free running on bearings (54) so mounted as to provide independently adjustable means of bringing pressure onto the wire as it is fed through the rollers (10, 11) whereby it may be shaped into a curve which facilitates winding thereof around the pipe (1).

[0019] In use of the apparatus in carrying out the method of the invention, as a start up procedure, the line (3) is drawn in a serpentine path through the rollers (4) and passed around the leading end of the first pipe (1) in the series which, because it is revolving, causes the line (3) to be wound around that end for a number of turns which has been found sufficient to secure it to that end. Thereafter, the line (3) need not be touched and it will continue to be drawn through the feed mechanism in an uninterrupted continuous manner for as long as there remains line on the spool and will thus be continuously wound round all pipes conveyed in series past the coating station. At a predetermined time after feeding the line through the apparatus onto the pipe (1), the wire mesh feed is started, whereupon the wire advances into contact with the line and becomes directed thus onto the pipe section. At this time also the concrete throwing device is operated causing a concrete layer to begin to build up on the revolving pipe before the wire comes into contact with it. Thereafter, the line and wire are fed together so that the line overlies the wound wire until the concrete coating has been applied. At a predetermined instance prior to complete coating of the pipe, the cutter assembly is operated to cut the wire and the drive rollers (6) are momentarily stopped to provide a gap between the end of one wire winding and the start of the next. In this way the wire is wound wholly within the length of the concrete coating, and is embedded therein without coming into direct contact with the anti-corrosion coating on the pipe. Additionally because the line is not cut it is still wound for several turns on after the cut end of wire is wound onto the pipe to provide a means which has been found sufficient to counter any "clock spring" effect of the wire within the still hardening concrete coating. This line is easily severed by the action of the accelerated conveyance of the coated pipe away from the station in a manner known in the art.

Claims

1. A method of coating pipes with concrete which comprises conveying a series of pipe sections past a concrete coating station, rotating a pipe section (1) about its longitudinal axis at the station, winding wire about said section and applying concrete to the outside of the pipe section during rotation thereof characterised by feeding a line (3) to the rotating pipe prior to the application of concrete to form a secured winding of line around the leading end of the pipe, subsequently feeding a wire (5) together with the line continuously to the rotating pipe in order to form a winding of wire overlaid by a winding of line on the pipe during the application of concrete to the rotating pipe, and cutting the wire at a predetermined time prior to completion of, and during the application of, the concrete coating whilst the pipe is still rotating whereby the wire is embedded in the concrete coating, and continuing to feed the line to the rotating pipe after cutting of the wire to wind the line around the tail end of the pipe.

2. A method according to claim 1 wherein the wire is formed into a curve prior to winding upon the pipe.

3. A method according to claim 1 wherein the line is made of a synthetic fibre material or a wire filament.

4. Apparatus for coating pipes with concrete comprising means for conveying a series of pipe sections (1) past a concrete coating station, means (2) for rotating a pipe section (1) about its longitudinal axis at the station, means (6) for feeding wire (5) to said section and means for applying concrete to the outside of the pipe section during rotation thereof characterised in that a line feed mechanism (4) for continuously feeding a line (3) to the rotating pipe is provided adjacent to a wire feed mechanism for continually feeding a length of wire to the rotating pipe section during coating with concrete, said wire feed mechanism including a cutter assembly (7, 8) for limiting the length of wire to be wound around the pipe section during coating of the rotating pipe section.

5. Apparatus according to claim 4 wherein the wire feed mechanism further comprises a wire shaping assembly (9, 10, 11, 12) for preforming the wire in a curved shape to facilitate winding thereof about a pipe section.

6. Apparatus according to claim 5 wherein the wire shaping assembly comprises a plurality of rollers (9, 10, 11, 12) at least one (11) of which provides a reaction surface over which wire is passed and against which wire may be shaped by the application of pressure from at least one other roller (9, 12) beneath which the wire is passed.

7. Apparatus according to claim 4 wherein the cutter assembly comprises a pair of rollers (7) each having a cutter blade (8) extending longitudinally across the roller surface and being mounted in parallel and driven by an electric motor (46) through a transmission system (47, 48, 49) providing for counter-rotation of the rollers and interruption of the cutting action to allow passage of wire therebetween.

8. Apparatus according to claim 4 wherein the line feed mechanism comprises a plurality of rollers (4) mounted in series through which line is fed in a serpentine fashion, at least one of which rollers is movable relative to the others to provide for alteration of tension applied to the line.

9. Apparatus according to claim 4 wherein the wire feed mechanism comprises a pair of rubber coated rollers (6) mounted in parallel and driven in a counter rotary fashion by an electric motor (26) through a mechanical transmission (27, 28) to advance wire through the mechanism, said rollers having screw adjuster means (29) for moving the rollers together or apart; a roller cutter assembly directly in the path of the wire as it exits from the driven rubber rollers, and having a pair of rollers (7) each having a cutter blade (8) extending longitudinally across the cutter roller surface, said cutter rollers being mounted in parallel and driven by an electric motor (46) through a mechanical transmission (47, 48) providing for counter-rotation of the cutter rollers, which transmission incorporates a clutch (49) enabling the cutter assembly to be disengaged to allow free passage of a length of wire between the cutter rollers; a wire shaping assembly comprising a plurality of rollers, (9, 10, 11, 12) including a pair mounted in (11, 12) parallel and driven by an electric motor (36) through a mechanical transmission system (37, 39) counter to each other to cause advancement of wire between them and other rollers so mounted as to provide independently adjustable means of bringing pressure onto the wire as it is fed through said pair of rollers whereby it may be shaped into a curve which facilitates winding thereof around a pipe section.

Ansprüche

1. Verfahren zum Beschichten von Rohren mit Beton, bei dem eine Folge von Rohrabschnitten durch eine Betonbeschichtungsstation transportiert wird und bei dem in der Station jeweils ein Rohrabschnitt (1) um seine Längsachse gedreht, Draht um den Abschnitt gewickelt und, während sich derselbe dreht, Beton auf die Außenseite des Rohrabschnittes aufgebracht wird, dadurch gekennzeichnet, daß dem sich drehenden Rohr vor dem Aufbringen von Beton ein Seil (3) zugeführt wird, um eine festliegende Bewicklung an dem Vorderende des Rohres auszubilden, daß darauffolgend gemeinsam mit dem Seil ein Draht (5) kontinuierlich dem sich drehenden Rohr zugeführt wird, um während des Aufbringens von Beton auf das sich drehende Rohr eine Drahtbewicklung zu erzeugen, über die eine Seilbewicklung gelegt ist, daß der Draht eine vorbestimmte Zeit vor dem Beenden und während des Aufbringens der Betonschicht auf das sich drehende Rohr abgeschnitten wird, während sich das Rohr noch immer dreht, wobei der Draht in die Betonschicht eingebettet wird, und daß, um das Seil um das hintere Ende des Rohres zu wickeln, das Seil nach dem Abschneiden des Drahtes dem sich drehenden Rohr weiter zugeführt wird.

2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der Draht vor dem Aufwickeln auf das Rohr kurvenförmig gekrümmt wird.

3. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß das Seil aus einem synthetischen Fasermaterial oder einem Drahtfilament hergestellt ist.

4. Vorrichtung zum Beschichten von Rohren mit Beton, mit Mitteln zum Fördern einer Folge von Rohrabschnitten (1) durch eine Betonbeschichtungsstation, mit Mitteln (2) zum Drehen eines Rohrabschnittes (1) in der Station um dessen Längsachse, mit Mitteln (6) zum Zuführen von Draht (5) zu dem Abschnitt sowie mit Mitteln zum Aufbringen von Beton auf die Außenseite des Rohrabschnittes während sich derselbe dreht, dadurch gekennzeichnet, daß angrenzend an eine Drahtzuführungseinrichtung zum kontinuierlichen Zuführen eines Drahtabschnittes zu dem sich drehenden Rohrabschnitt während der Beschichtung mit Beton eine Seilzuführungseinrichtung (4) zum kontinuierlichen Zuführen eines Seiles (3) auf das sich drehende Rohr vorgesehen ist, wobei die Drahtzuführungseinrichtung eine Schneidvorrichtung (7, 8) zum Begrenzen der Länge des Drahtes aufweist, die während der Beschichtung des sich drehenden Rohrabschnittes um den Rohrabschnitt zu wickeln ist.

5. Vorrichtung nach Anspruch 4, dadurch gekennzeichnet, daß die Drahtzuführungseinrichtung außerdem eine Drahtformungseinrichtung (9, 10, 11, 12) zum Vorformen des Drahtes in eine gekrümmte Form aufweist, um das Aufwickeln desselben auf den Rohrabschnitt zu erleichtern.

6. Vorrichtung nach Anspruch 5, dadurch gekennzeichnet, daß die Drahtformungseinrichtung eine Anzahl Rollen (9, 10, 11, 12) aufweist, von denen wenigstens eine (11) eine Abstützfläche aufweist, über die der Draht geführt ist und gegen die der Draht durch die Anwendung von Druck von wenigstens einer weiteren Rolle (9,12), unter der der Draht durchgeführt ist, geformt werden kann.

7. Vorrichtung nach Anspruch 4, dadurch gekennzeichnet, daß die Schneidvorrichtung ein Paar Rollen (7) aufweist, von denen jede eine sich in Längsrichtung über die Mantelfläche erstreckende Schneidklinge (8) aufweist, und die parallel zueinander angeordnet sowie durch einen Elektromotor (46) über eine Kraftübertragungseinrichtung (47, 48, 49) angetrieben sind, die zur Erzeugung einer gegensinnigen Drehung der Rollen sowie einer Unterbrechung des Schneidvorganges eingerichtet ist, um Draht zwischen diesen durchgehen zu lassen.

8. Vorrichtung nach Anspruch 4, dadurch gekennzeichnet, daß die Seilzuführungseinrichtung eine Anzahl von Rollen (4) aufweist, die in einer Reihe angeordnet sind, durch die das Seil schlangenförmig durchgeführt ist, wobei wenigstens eine der Rollen in Bezug auf die anderen beweglich angeordnet ist, um dadurch die auf das Seil übertragene Spannung ändern zu können.

9. Vorrichtung nach Anspruch 4, dadurch gekennzeichnet, daß die Drahtzuführungseinrichtung aufweist: ein Paar gummiummantelter Rollen (6), die parallel zueinander angeordnet und durch einen Elektromotor über eine Kraftübertragungseinrichtung (27, 28) gegensinnig angetrieben sind, um den Draht durch die Einrichtung zu befördern, wobei die Rollen mit Stellspindeln (29) zur Bewegung der Rollen aufeinander zu und voneinander weg versehen sind; eine auf dem von den angetriebenen Gummirollen ausgehenden Weg des Drahtes angeordnete Rollenschneidvorrichtung, die ein Paar Rollen (7) aufweist, von denen jede eine Schneidklinge (8) aufweist, die sich jeweils in Längsrichtung entlang der Mantelfläche der Schneidrolle erstreckt, wobei die Schneidrollen parallel zueinander angeordnet und von einem Elektromotor (46) über eine zur Erzeugung einer gegensinnigen Drehung der Schneidrollen vorgesehene Kraftübertragungseinrichtung (47, 48) angetrieben sind, wobei die Kraftübertragungseinrichtung eine das Ausrücken der Schneidvorrichtung erlaubende Kupplung (49) enthält, um den freien Durchgang einer Länge Drahtes zwischen den Schneidrollen zu ermöglichen; sowie eine Drahtformungseinrichtung, die eine Anzahl von Rollen (9, 10, 11, 12,) aufweist, von denen ein Paar (11, 12) parallel zueinander angeordnet und von einem Elektromotor (36) über ein Kraftübertragungssystem (37, 39) gegensinnig zueinander angetrieben sind, um das Durchfördern des Drahtes zwischen ihnen und anderen Rollen zu bewirken, die so angeordnet sind, daß sie voneinander unabhängig einstellbare Mittel zum Ausüben einer Druckkraft auf den das Rollenpaar durchlaufenden Draht bilden, wobei dieser in eine gekrümmte Form gebracht werden kann, um dadurch das Aufwickeln desselben um den Rohrabschnitt zu erleichtern.

Revendications

1. Procédé d'enduction de conduite avec du béton qui comprend le convoyage d'une série de tronçons de conduite devant un poste d'enduction de béton, la mise en rotation d'un tronçon de conduite (1) autour de son axe longitudinal au poste d'enduction, l'enroulement d'un grillage autour dudit tronçon et l'application de béton sur l'extérieur du tronçon de conduite pendant sa rotation caratérisé par l'avance d'une ligne (3) vers la conduite en rotation avant l'application de béton pour former un enroulement fixé de la ligne autour de l'extrémité avant de la conduite, application ultérieure d'un grillage (5) en même temps que la ligne en continu sur la conduite en rotation afin de former un enroulement de grillage recouvert par un enroulement de ligne sur la conduite pendant l'application de béton sur la conduite en rotation, et la coupe du grillage à un instant prédéterminé avant l'achèvement, et pendant l'application de l'enduit de béton tandis que la conduite est encore en rotation afin que le grillage soit enrobé dans l'enduit de béton, et en faisant avancer en continu la ligne vers la conduite en rotation après la coupe du grillage pour enrouler la ligne autour de l'extrémité arrière de la conduite.

2. Procédé selon la revendication 1 dans lequel le grillage est mis en forme cintrée avant d'être enroulé sur la conduite.

3. Procédé selon la revendication 1 dans lequel la ligne est fabriquée en matière fibreuse synthétique ou en filament métallique.

4. Appareil pour enduire des conduits avec du béton comprenant un moyen pour acheminer une série de tronçons de conduite (1) devant un poste d'enduction par du béton, un moyen (2) pour faire tourner un tronçon de conduite (1) autour de son axe longitudinal audit poste d'enduction, un moyen (6) pour faire avancer un grillage (5) vers ledit tronçon et un moyen pour appliquer du béton à l'extérieur du tronçon de conduite pendant la rotation de ce tronçon, caractérisé en ce qu'un mécanisme d'avance de ligne (4) pour faire avancer une ligne en continu vers la conduite en rotation est installé à côté d'un mécanisme d'avance du grillage pour faire avancer en continu une longueur de grillage vers le tronçon de conduite en rotation pendant son enduction par du béton, ledit mécanisme d'avance du grillage comprenant un ensemble de coupe (7, 8) pour limiter la longueur de treillage à enrouler autour du tronçon de conduite pendant l'enduction du tronçon de conduite en rotation.

5. Appareil selon la revendication 4 dans lequel le mécanisme d'avance du grillage comprend en outre un ensemble de mise en forme du grillage (9, 10, 11, 12) pour préformer le grillage en lui donnant une forme cintrée afin de faciliter son enroulement autour d'un tronçon de tuyau.

6. Appareil selon la revendication 5 dans lequel l'ensemble de mise en forme du grillage comprend plusieurs rouleaux (9, 10, 11, 12) dont un au moins constitue une surface de réaction sur laquelle passe le grillage et contre laquelle le grillage peut êre mis en force par application de la pression d'un au moins des autres rouleaux (9, 12) sous lequel passe le grillage.

7. Appareil selon la revendication 4 dans lequel l'ensemble de coupe comprend une paire de rouleaux (7) portant chacun une lame tranchante (8) orientée longitudinalement en travers de la surface du rouleau et étant montée en parallèle et entraînée par un moteur électrique (46) par l'intermédiaire d'un système de transmission (47, 48, 49) assurant la rotation en sens inverse des rouleaux et l'interruption de l'action de coupe pour laisser passer le grillage entre eux.

8. Appareil selon la revendication 4 dans lequel le mécanisme d'avance de la ligne comprend plusieurs rouleaux (4) montés en série entre lesquels la ligne avance en serpentin, un au moins de ces rouleaux étant mobile par rapport aux autres pour modifier la tension appliquée à la ligne.

9. Appareil selon la revendication 4 dans lequel le mécanisme d'avance du grillage comprend deux rouleaux (6) recouverts de caoutchouc montés en parallèle et entraînés en rotation en sens inverse par un moteur électrique (26) par l'intermédiaire d'une transmission mécanique (27, 28) pour faire passer le grillage à travers le mécanisme, lesdits rouleaux ayant des moyens de réglage à vis (29) pour déplacer les rouleaux ensemble ou les écarter ; un ensemble de rouleaux de coupe placés directement sur le passage du grillage quand il sort des rouleaux d'entraînement recouverts de caoutchouc et comprenant une paire de rouleaux (7) et portant chacun une lame tranchante (8) orientée longitudinalement à travers la surface du rouleau de coupe, lesdits rouleaux de coupe étant montés en parallèle et entraînés par un moteur électrique (46) par l'intermédiaire d'une transmission mécanique (47, 48) assurant la rotation en sens inverse des rouleaux de coupe, laquelle transmission comporte un embrayage (49) permettant de débrayer l'ensemble de coupe de façon à laisser passer librement une longueur de grillage entre les rouleaux de coupe, un ensemble de mise en forme de grillage comportant plusieurs rouleaux (9, 10, 11, 12) parmi lesquels une paire de rouleaux (11, 12) montés en parallèle et entraînés par un moteur électrique (36) par l'intermédiaire d'un système de transmission mécanique (37, 39) en sens inverse l'un de l'autre afin de créer l'avance du grillage entre eux et d'autres rouleaux qui sont montés de façon à constituer un moyen de réglage indépendant d'application d'une pression sur le grillage au moment où il avance entre les deux rouleaux et de façon à lui donner une forme cintrée qui facilite son enroulement autour d'un tronçon de conduite.

Drawing