EP0280626A1 - System for unfolding and placing a bridge from a vehicle such as a bridge-laying tank for passing an obstacle - Google Patents

Abstract

The present invention relates to a system for spreading and depositing a spanning beam from a vehicle wherein, in the transport position of the spanning beam on the vehicle, the outer extreme element of the spanning beam is pivotally supported and maintained at its free end by a mobile support device of the vehicle occupying a raised position while the inner extreme element of the spanning beam rests on the outer extreme element along same and wherein the spanning beam can be raised by winding of the working cable on a winch of the vehicle into a position where the inner extreme element is pivotally supported at its free end by the support device with concomitant release of the free end of the outer extreme element from the device.

Description

The present invention relates to a system for deploying and removing, from a vehicle such as an armored engineering vehicle, a span for crossing an obstacle formed for example by a breach which may possibly be located in an area contaminated NBC (Chemical Bacteriological Nuclear).

Deployment systems are known for such vertically pivoting spans and comprising at least two successive main elements, an internal extreme element and an external extreme element which can be folded down against the internal extreme element along the latter and hinged mounted. one relative to the other towards their adjacent ends by an articulation axis substantially perpendicular to the longitudinal axis of the span which is fixed at at least one point of one of the two internal and external extreme elements to at least one control cable winding for example on at least one winch placed on the vehicle.

However, these known systems comprise at least one control means constituted for example by a jack for ensuring the rotation of the outer extreme element relative to the inner extreme element around the axis of articulation. Such control means have the disadvantage of weighing down the span and above all consuming a lot of additional energy.

The present invention aims to eliminate the above drawbacks of the systems known in proposing a system for deploying and removing a span that does not require any additional control means or energy source.

For this, the deployment and removal system according to the invention is characterized in that in a position for transporting the span on the vehicle, the external extreme element is supported and pivotally held at its free end by a mobile support device for the vehicle occupying a raised position while the internal element rests along the external extreme element; in that the span is liftable by winding the operating cable on the winch in a position where the inner end element is pivotally supported at its free end by the support device with concomitant release of the free end of the external end element of the support device; in that the support device is then lowered to a support position on the ground to cause a separation of the outer extreme element from the inner extreme element and thus allow the deployment of the span; and in that the operating cable is unwound from the winch to lower and deposit the span above the breach.

According to a characteristic of the invention, the free end of the internal external end element is released from the support device by the vehicle moving back relative to the span.

According to another characteristic of the invention, the support device comprises at least one member for locking the free end of the end element external to said device and unlocked when the free end of the internal end element comes support on the support device in the raised position of the span.

Still according to another characteristic of the invention, the locking member comprises a part forming a hook retaining to the device for supporting an axis of the free end of the external extreme element, arranged transversely to the longitudinal axis of the span, and being able to pivot relative to the support device in the unlocking direction against the return force of an elastic member such as a tension spring and, integral with the hook part, a part forming pivot arm of the hook part actuated by an axis of the free end of the internal end element disposed transversely to the longitudinal axis of the span in the raised position of the span.

According to yet another characteristic of the invention, the support device further comprises at least two parallel plates perpendicular to the ground secured to a support element of the device and a support piece of the respective end axes of the two extreme elements internal and external, pivotally mounted between the two plates and able to cooperate alternately with two stops integral with the plates limiting the pivoting movement of the support piece at two extreme angular positions, one supporting the end axis of the extreme external element in the position for transporting the span and the end axis of the internal extreme element in the raised and deploying positions of the span, and the other for releasing the end axis of the internal extreme element when the vehicle is reversing.

According to yet another characteristic of the invention, the support piece comprises two recesses with rounded support bottom respectively of the two end axes of the internal and external end elements and the hook part of the locking member cooperates with the bearing recess of the end axis of the external end element and a front edge of each of the parallel plates to lock said axis in the position of transport of the span.

Still according to another characteristic of the invention, the locking member, produced in one piece with the pivot arm opposite the hook portion, is pivotally mounted in the support piece, which pivot arm projects in the support recess of the end axis of the internal end element in the position for transporting the span.

• Les figures 1A-1H représentent un véhicule équipé du système de l'invention à différentes positions pour le déploiement et la dépose d'une travure au-dessus d'une brèche ;
• La figure 2 est une vue agrandie de la partie cerclée en II en figure 1A ;
• La figure 3 est une vue agrandie de la partie cerclée indiquée en III de la figure 1G ;
• La figure 4 représente en détail le mécanisme de commande du dispositif de support de la travure et disposé à l'avant du véhicule ;
• La figure 5 est une vue agrandie du dispositif de support de la travure dans la partie cerclée indiquée en V par exemple à la figure 1B et représentant plusieurs positions des extrémités des deux éléments principaux formant la travure ;
• La figure 6 est une vue agrandie de la partie cerclée indiquée en VI en figure 1G ;
• La figure 7 représente le dispositif de support en position permettant le dégagement de la travure de celui-ci ;
• La figure 8 est une vue de dessus suivant la flèche VIII en figure 3 ; et
• La figure 9 est une vue suivant la flèche IX de la figure 7 avec coupe partielle.

The invention will be better understood and other objects, characteristics, details and advantages thereof will appear more clearly during the explanatory description which follows, made with reference to the appended schematic drawings given solely by way of example illustrating a mode of the invention and in which:

• FIGS. 1A-1H represent a vehicle equipped with the system of the invention at different positions for the deployment and the removal of a span above a breach;
• Figure 2 is an enlarged view of the part circled in II in Figure 1A;
• Figure 3 is an enlarged view of the circled portion indicated in III of Figure 1G;
• Figure 4 shows in detail the control mechanism of the device for supporting the span and disposed at the front of the vehicle;
• Figure 5 is an enlarged view of the device for supporting the span in the circled part indicated in V for example in Figure 1B and showing several positions of the ends of the two main elements forming the span;
• Figure 6 is an enlarged view of the circled portion indicated in VI in Figure 1G;
• Figure 7 shows the support device in position for the release of the span thereof;
• Figure 8 is a top view along arrow VIII in Figure 3; and
• Figure 9 is a view along arrow IX of Figure 7 with partial section.

Referring to FIGS. 1A to 1H, the reference 1 designates a vehicle, in particular an armored engineering vehicle comprising a support device 2 of a span 3 fixed at at least one point 4 to at least one operating cable 5 winding for example on at least one winch (not shown) placed on the vehicle 1. The operating cable 5 is connected to the winch via a pulley spreader 6 articulated to an arm 7 of the vehicle 1, which arm is held on the vehicle by guying 8.

The support device 2 comprises a support element proper 2a constituted in the present case by a part forming a hollow blade similar to that of a bulldozer. The support device 2 is mounted movable relative to the vehicle 1 between a raised position shown in dotted lines in FIG. 4 and a lowered position on the ground. For this, a main arm 1a is pivotally mounted at one of its ends on the vehicle 1 and is secured at its other end to the lower part of the support device 2. The main arm 1a is secured to a deflection arm 1b, the free end of which is connected to the free end of a rod of a control member constituted for example by a hydraulic cylinder 1c placed on the vehicle. A reinforcing arm 1d is disposed between the middle part of the main arm 1a and the upper part of the support device 2. Since such a mechanism for raising and lowering a blade is already known per se, it does not have to be described in more detail.

The span 3 comprises at least two successive main elements, an internal extreme element 3a and an external extreme element 3b, mounted articulated with respect to each other towards their adjacent ends by an articulation axis 3c substantially perpendicular to the axis. longitudinal X-Xʹ of the span (see Figure 8).

The operating principle of the system of the invention will be described with reference to Figures 1A to 1H.

The operating cable 5, attached in this case to the outer end element 3b of the span 3 in traveling on this element as will be described in more detail later and on the pulleys of the spreader 6 fixed on the arm 7 of the vehicle 1, maintains the span 3 on the support device 2 in the transport configuration of the span shown in FIG. 1A. In this position for transporting the span, the external extreme element 3b is supported and pivotally held at its free end by the support device 2 occupying the raised position while the internal extreme element 3a rests on the extreme element external 3b along the latter via a buffer device represented schematically by the reference 3d and secured for example to the element 3b. It should be noted that the free end of the element 3a in the transport position is completely released, that is to say that this element is not at all supported on the support device 2. In addition , a locking member, which will be described in more detail later, mounted on the support device 2, maintains the free end of the element 3b to the support device 2. The span 3 is thus transported by the vehicle 1 which is positions on the selected launching area represented in this case by a breach B.

Once the vehicle is positioned, the span 3 is raised by winding the operating cable 5 on the winch of the vehicle to the position shown in FIG. 1B, close to the vertical position, and at which the internal extreme element 3a is supported pivotally at its free end by the support device 2 with concomitant release of the free end of the external end element 3b of the support device. In the raised position of FIG. 1B, the support device 2 always occupies the raised position of FIG. 1A. It is understood that the lifting of the span makes it possible to pass from a portage of the external extreme element 3b to the internal extreme element 3a, the change of fulcrum of the span on the support 2 allowing the lower part to be released of the external end element 3b by actuating the locking member of the free end of this element as will be described later. In the raised position of FIG. 1B, the center of gravity of the span is practically centered at the bearing end of the internal extreme element on the device so that the external extreme element is folded back against the extreme element internal.

The support device 2 is then lowered as indicated by the arrow A so as to lower the fulcrum of the internal extreme element 3a on the device 2 and separate the external extreme element 3b from the internal extreme element 3a and thus allow the deployment of the span as shown in Figure 1E. During the lowering of the support device 2, the operating cable 5 runs on a lateral extension 3b1 of the element 3b so that it acts as a lever arm around the articulation axis 3c to facilitate the spacing of the outer end member 3b from the inner end member 3a. It should be noted that from the raised position of the span shown in FIG. 1B to the deployed position of the latter shown in FIG. 1E, the length of the operating cable 5 remains constant so that only the lowering of the support device 2 , taking into account the routing of the cable on the extension 3b1 and its point of attachment 4, ensures the deployment of the span 3.

From the deployment position of the span shown in FIG. 1E and at which the support device 2 rests on the ground, the operating cable 5 is unwound from the winch to lower and deposit the span 3 above the breach B as shown in Figure 1F.

Once the span deposited above the breach, the operating cable 5 is unwound further from the winch to give it slack and automatically release it from its point of attachment to the external extreme element 3b in the manner which will be described later (see Figure 1G).

The vehicle 1 is then moved backwards with respect to the span 3 as indicated by the arrow R in FIG. 1H to release the end of the internal end element 3a from the span of the device 2 and release the operating cable 5 from that -this.

After using the span, the span is folded as follows.

The vehicle 1 approaches the span with the support device 2 in the lowered position so that the latter lifts the end of the internal extreme element 3a and positions it at its point of support on the device 2. The cable 5 is then fixed to an anchor or attachment point of the internal end element 3a located near its end opposite to its point of support on the device 2. The cable 5 is then wound on the winch so as to raise the span to the approximately vertical position shown in Figure 1B. During this lifting phase of the span, the external extreme element 3b flap towards and against the inner end element along the latter and the support device 2 passes from the lowered position to the raised position. In the raised position of FIG. 1B, the center of gravity of the span is centered practically at the bearing end of the internal extreme element on the device 2 so that the external extreme element 3b is well folded against the inner extreme element. The operating cable 5 is then unwound from the winch to bring the span to an angular position corresponding to that shown in FIG. 1A (for example around 30 ° relative to the ground). Of course, at this position, the external end element 3b is locked and held on the support device 2 and the other element 3a rests on the element 3b. A trailer (not shown) is then brought closer to the span in its longitudinal axis. The operating cable 5 is again unwound to bring the end of the span opposite its end in abutment on the device 2 on the trailer in a configuration such as the fulcrum of the internal end element on the device 2 either at a height somewhat higher than that of the opposite end of the span. The support device 2 is then lowered so as to place the span completely on the trailer and the unlocking member is actuated manually to release the free end of the internal end element 3b of the device 2.

The recovery of the span of the trailer on the support device 2 is accomplished by approaching the trailer of the device so that the free end of the external end element 3b is brought opposite the locking member of the device and locked manually in this one. The cable maneuver 5 partially wound on the extension 3b1 is fixed to the fixing point 4 is then wound on the winch so as to raise the span around its point of articulation on the device 2 and bring it to the transport position shown in figure 1A. The span is then ready for a new deployment process on another breach.

Referring to Figures 2, 3 and 8 there will be described in detail the structure and operation of the point of attachment of the end of the cable 5 to the outer end member 3b allowing automatic release of the cable in the deployed position of the span. The fixing point 4 consists of a support plate 4a of a piece forming a hook 4b and which can cooperate alternately with two stops 9 and 10 integral with the extension 3b1 of the external end element to limit the pivoting movement of the plate 4a around an axis 4a1 integral with the extension 3b1 at two extreme angular positions respectively for hooking the operating cable 5 as shown in FIG. 2 and for unhooking the cable as shown in FIG. 3. An elastic return member such as for example a tension spring 11 is connected at one of its ends to the support plate 4a and at its other end to the extension 3b1. This spring tends to bring the support plate 4a against the stop 10. The hook piece 4b is pivotally mounted about an axis 4b1 secured to the support plate 4a and has a tab 4b2 projecting to which the end is connected an elastic return member 12 also constituted for example by a spring, the other end of which is connected to the common point of attachment of the end of the spring 11 on the plate 4a. The spring 12 tends to recall the hook piece 4b clockwise from plate 4a. The extension forming the lateral lever arm 3b1 of the external extreme element 3b is laterally integral with the latter, in the vicinity of its axis of articulation with the element 3a as is clearly shown in FIG. 8, and extends substantially parallel to the longitudinal axis of the element 3b beyond the axis 3c. The assembly constituted by the support plate 4a and the hook-forming part 4b is housed in the arm 3b1 in the vicinity of the end of the external extreme element 3b close to the axis 3c. The arm 3b1 has at its free end, of rounded shape, a guide path for the operating cable 5. The latter is connected to the hook of the part 4b by means of a yoke 13.

The internal end element 3a also comprises, laterally integral with the latter, and in the vicinity of the axis 3c, an extension forming a lateral lever arm 3a1 identical to the arm 3b1 and which extension 3a1 comprises a fixing point 4 of a structure and operation identical to the attachment point 4 described in Figure 2. The arm 3a1 extends substantially parallel to the longitudinal axis of said element beyond the axis 3c.

In the position for transporting the span shown in FIG. 2, the cable 5 runs over the extreme periphery of the arm 3b1 and exerts traction on the hook piece 4b by means of the yoke 13. The hook piece 4b, against the return action of the spring 12 comes to bear against a corresponding part of the support plate 4a, which is in forced support against the stop 9 against the return action of the spring 11. The position of the point fixing 4 by relative to the extension 3b1 shown in Figure 2 is maintained during the lifting and deployment phases of the span. When the span is placed on the breach B as shown in FIG. 1G, the winch is actuated so as to give slack to the cable 5. In this condition, as shown in FIG. 3, the spring 11 recalls the support plate 4a against the stop 10 and spring 12 recalls the hook piece 4b clockwise relative to the plate 4a to a position where the yoke 13 of the cable 5 is released by gravity from the hook of the piece 4b. The pivoting movement of the part 4b relative to the plate 4a is limited by a foot 4b3 coming to bear on a corresponding part of the plate 4a.

FIG. 8 also represents a damping device 14 constituted for example by a jack mounted along the axis X-Xʹ and the body 14a of which is integral with the external end element 3b and the rod 14b, passing over the axis 3c, is integral at its free end with the internal end element 3a. The damping device 14 has the effect of delaying the effect of acceleration of the opening movement of the span 3 created before the complete deployment of the span.

The support device 2 will now be described in detail with reference to FIGS. 5-7 and 9.

This device comprises at least two parallel plates 2b, integral with the blade 2a and situated respectively in a plane transverse to the blade 2a and therefore perpendicular to the ground. Each plate 2b has an arcuate part conjugated to the hollow part of the blade 2a to come to bear on the latter and has at its upper end a curved part 2b1 enclosing the upper part of the blade 2a. A fixing member, such as for example a screw symbolized by a dashed line, can be provided at the upper part of the blade 2a to perfect the fixing of the plate 2b to the blade 2a. The plates 2b further comprise respectively two front edges 2b2 connected at the level of the lower part of the plates to a part forming a nose 2b3 to form a guide path for the end of the internal end element 3b of the span as will be explained further.

The support device 2 further comprises a support piece 2c of the respective ends of the end elements 3a and 3b, pivotally mounted between the two plates 2b around an axis 2c1 arranged transversely between the two plates 2b and capable of cooperating alternately with two abutments 15 and 16 integral with the plates limiting the pivoting travel of the support piece to two extreme angular positions, one supporting the end of the external extreme element 3b in the position for transporting the span shown in I in FIG. 5 and of the end of the internal extreme element 3a in the raised positions (shown in II in FIG. 5) and of deployment of the span, and the other of release of the end of the element internal end 3a when the vehicle 1 recedes as shown in FIG. 7.

The support piece 2c comprises two recesses 2c2 and 2c3 with rounded support bases respectively of two axes 3a2 and 3b2 of respective ends of the inner and outer end elements 3a and 3b. The axes 3a2 and 3b2 are arranged transversely to the longitudinal axis of the span respectively at the ends of the internal extreme element and the external extreme element. The support piece 2c further comprises two axes 2c4 and 2c5 projecting transversely on either side of the support piece and at the respective end of each of which is fixed the end of a tension spring 17 now the support piece 2c at one or the other of its extreme angular positions. As best represented in FIG. 9, the axes 2c4 and 2c5 each pass through an oblong bean-shaped hole 2b4 produced through each of the plates 2b. During the movement of the support piece 2c at the two extreme angular positions mentioned above, the axes 2c4 and 2c5 move in their corresponding oblong hole.

The support device 2 also comprises a locking member 2d of the end axis of the external end element 3b to said device and mounted to pivot inside the support piece 2 around an axis 2d1 mounted transversely in the support piece 2c. The locking member 2d, produced in one piece, comprises a part forming a retaining hook 2d2 of the axis 3b2 in the position for transporting the span as well as in the position of the latter on the trailer shown diagrammatically in III in FIG. 5 and projecting at these positions from the recess 2c3 to maintain the axis 3b2 in a retaining space defined in part by the recess 2c3 and the front edges of the plates 2b. The locking member 2d further comprises a part forming a pivot arm 2d3 of the hook-forming part, opposite the latter and projecting from the recess 2c2 of the support piece 2c in the position for transporting the span. An elastic member, such as for example a tension spring 18, connected at its free ends respectively to an attachment point secured to the locking member and to a fixing axis 2c6 secured to the part support 2c, recalls the locking member 2d in its locking direction.

Preferably, two pairs of parallel plates 2b each comprising the support piece 2c-locking member 2d assembly are mounted on the blade 2a symmetrically to the longitudinal axis of the vehicle 1 which coincides with the axis X-Xʹ of the span mounted on the vehicle.

The operation of the support device 2, which already follows in part from the foregoing explanations, will now be described in more detail below.

When the support device 2 is in the raised position for transporting the span, the axis 3b2 of the end of the element 3b is held on and to the device 2 by the hook part 2d2 of the locking member 2d . When raising the span to the approximately vertical position, the end axis 3a2 of the element 3a by contacting the arm 2d3 pivots the hook part in the unlocking direction shown in dotted lines in FIG. 5, thus releasing the end axis 3a2 of element 3b. Of course, the end axis 3d2 of the element 3a is supported in the recess 2c2 of the support piece 2c to ensure the pivoting of the span during deployment. Figure 6 shows the end part of the internal element 2a supported by its end axis 3a2 in the recess 2c2 when the span is deployed and deposited as shown in Figure 1G. From this position, the vehicle 1 is moved back in the direction of the arrow R as shown in FIG. 7 so as to move the support device 2 in the same direction and bring the end of the element internal 3a to move by gravity first along a branch 2c7 of the part 2c defined between the two recesses 2c2 and 2c3 to trigger the pivoting of the part 2c against the stop 16. Then, the edges 2b2 of the plates 2b and the nose 2b3 form the guide path of the end axis 3a2 of the element 3a in the downward direction as indicated by the arrows D so as to deposit the end of the element 3a and therefore the span on the launch pad. After using the span, the recovery of the element 3a is carried out by advancing the nose portion of the plates 2b towards the end axis 3a2 to resume it on the nose and the edges 2b2 forming the guide path and the bring in its support recess 2c2 as indicated by the arrows A in FIG. 7. Before being housed in the recess 2c2, the end axis 3a2 exerts a pivoting action on the support piece 2c towards the position extreme angular defined by the stop 15. The device is then found in the position shown in Figure 6. The span is then raised as already described above to then be placed on the trailer. The unlocking of the end axis 3b2 of the element 3b before complete installation of the span on the trailer is ensured by manually exerting pressure on the pivot arm 2d3 of the hook part 2d2.

Of course, instead of resuming and raising the span when the vehicle 1 is in the position indicated in FIG. 1H, it is also possible to resume it when the vehicle is on the other side of the breach, the external extreme element then becoming the internal extreme element while the internal extreme element becomes the external extreme element. In addition, the deployment of the span can operate from vehicle 1 located opposite the breccia B where the vehicle is located as shown in Figure 1A. In this case, it is the hook assembly 4 in the arm 3a1 which will fulfill the function accomplished by the hook assembly 4 of the arm 3b1 It should also be noted that the fixing point allowing the cable to be secured maneuver 5 to raise the span may be the hook assembly 4 of the internal end element.

Furthermore, the mechanism shown in FIG. 4 has been given by way of example, it being understood that other mechanisms ensuring functions identical to the described mechanism can be used. Finally, if the present invention has been described with reference to an armored engineering vehicle, it nevertheless also applies to other vehicles having the same functions.

Claims (17)

1. Deployment and removal system from a vehicle such as an armored engineering vehicle, a span for crossing an obstacle formed for example by a breach, vertically pivoting and occupying a transport position on the vehicle and having at least two successive main elements, an internal extreme element and an external extreme element which can be folded down against the internal extreme element along the latter, mounted articulated with respect to each other towards their ends adjacent by an articulation axis substantially perpendicular to the longitudinal axis of the span which is fixed at at least one point of one of the two internal and external extreme elements to at least one operating cable winding for example on at minus a winch placed on the armored vehicle; characterized in that in the span transport position (3), the external end element (3b) is supported and pivotally held at its free end by a mobile support device (2) for the vehicle (1) occupying a raised position while the inner end member (3a) rests on the outer end member (3b) along the latter, in that the span (3) is liftable by winding the operating cable (5) on the winch in a position where the internal end element (3a) is pivotally supported at its free end by the support device (2) with concomitant release of the free end of the external end element (3b) from the support device (2), in that the support device (2) is then lowered to a support position on the ground to cause a separation of the external end element (3b) from the internal end element (3a ) and thus allow the deployment of the span (3) and in that the operating cable (5) is unwound from the winch to lower and deposit the span (3) above the breach (B). 2. System according to claim 1, characterized in that the free end of the internal end element (3a) is released from the support device (2) by retraction of the vehicle (1) relative to the span (3). 3. System according to claim 1, characterized in that the aforementioned support device (2) comprises at least one locking member (2d) of the free end of the external extreme element (3d) to said device and unlocked when the the free end of the internal end element (3a) comes to bear on the support device (2) in the raised position of the span (3). 4. System according to claim 1, characterized in that the aforementioned locking member (2d) comprises a portion forming a retaining hook (2d2) to the support device (2) of an axis (3b2) of the free end of the external end element (3b) disposed transversely to the longitudinal axis (X-Xʹ) of the span, and which can pivot relative to the support device (2) in the unlocking direction against the force of return of a spring (18) and, integral with the hook part (2d2), a pivot arm part (2d3) of the hook part actuated by an axis (3a2) of the free end of the element internal end (3a), arranged transversely to the longitudinal axis (X-Xʹ) of the span (3) in the raised position of the span. 5. System according to claim 1, characterized in that the support device (2) further comprises at at least two parallel plates (2b) integral with a support element (2a) of said device and a support piece (2c) of the respective end axes of the two internal and external extreme elements (3a; 3b), pivotally mounted between the two plates (2b) and which can cooperate alternately with two stops (15, 16) integral with the plates (2b) limiting the pivoting movement of the support piece (2c) to two extreme angular positions, one of the end axis (3b2) of the external end element (3b) in the position for transporting the span (3) and the end axis (3a2) of the internal end element (3a) at the raised and deployment positions of the span, and the other of the release of the end axis (3a2) of the internal extreme element (3a) when the vehicle is reversing (1). 6. System according to claim 5, characterized in that the abovementioned support piece (2c) comprises two recesses (2c2, 2c3) with rounded support bottom respectively of the two end axes (3a2, 3b2) of the extreme elements internal and external (3a, 3b), and in that the hook part (2d2) of the locking member (2d) cooperates with the support recess (2c3) of the end axis (3b2) of the outer extreme element (3b) and a front edge (2b2) of each of the plates (2b) to lock said axis in the position of transport of the span (3). 7. System according to claim 6, characterized in that the locking member (2d), made in one piece with the pivoting arm (2d3) opposite the hook part (2d2), is pivotally mounted in the room support (2c) and in that the pivoting arm (2d3) of the locking member (2d) projects into the support recess (2c2) of the axis end (3d2) of the internal external element (3a) to the position of transport of the span (3). 8. System according to claim 6, characterized in that the aforementioned front edges of the aforementioned plates (2b) form with an inner part forming a nose (2b3) a guide path for the end axis (3a2) of the end of the internal end element (3a) when disengaging said axis and resuming it towards the locking position. 9. System according to one of the preceding claims, characterized in that the support piece (2c) comprises at least one axis (2c4; 2c5) projecting laterally from said piece and being able to move in an oblong hole in the form of bean (2b3) produced in at least one of the parallel plates (2b) during the movement of the support piece (2c) at the two abovementioned extreme angular positions. 10. System according to claim 9, characterized in that an elastic member, such as a tension spring (17), is fixed at its free ends respectively to the aforementioned axis of the support piece (2c) and to another axis integral with the plate (2b). 11. System according to claim 4, characterized in that the return spring (18) of the locking member (2d) is connected at its free ends respectively to an attachment point integral with said member and to another attachment point secured to the support piece (2c). 12. System according to claim 1, characterized in that it further comprises a damping device (14), preferably a jack, connected between the two internal and external extreme elements (3a, 3b) above the articulation axis (3c) of the two elements. 13. System according to claim 1, characterized in that, for the deployment of the span (3), the fixing point (4) is integral with the external end element (3b) and is constituted by a hook assembly ( 4a, 4b) pivotally mounted laterally on the outer extreme element (3b) and capable of cooperating alternately with two stops (9, 10) integral with said element, limiting the pivoting travel of the hook assembly to two extreme angular positions respectively hooking of the operating cable (5) during transport, lifting and deployment of the span (3) and disengagement of the cable end (5) by gravity of the hook (4b) once the span is removed, said end piece being constituted for example by a yoke (13). 14. System according to one of the preceding claims, characterized in that at least one or each end element (3a; 3b) comprises in the vicinity of its axis of articulation (3c) with the other end element an arm lateral (3a1; 3b1) integral with said end element and extending substantially parallel to the longitudinal axis of said end element beyond the common axis of articulation (3c) between the two end elements. 15. System according to claim 14, characterized in that in each lateral arm (3a; 3b) is housed a hook assembly (4a, 4b) mentioned above and in that each arm comprises an end portion for guiding the operating cable ( 5) during transport, lifting and deployment of the span (3), the lateral arm cooperating with the cable (5) during deployment to form a lever arm around the articulation axis (3c) of the two extreme elements (3a1, 3b). 16. System according to claim 5, characterized in that the aforementioned support element (2a) of the two parallel plates (2b) is formed by a hollow blade similar to that of a bulldozer. 17. System according to one of the preceding claims, characterized in that it comprises two pairs of parallel plates (2b) each comprising a support piece (2c) - locking member (2d) and integral with the element support symmetrically to the longitudinal axis of the vehicle (1).

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