| Patent claims 1. A mobile emergency bridge comprising a bridge structure consisting of an expandable, stiffenable and collapsible bearer frame and actuators that move the latter, including the supplementary subassemblies, wherein the bearer frame comprises scissor-like paired rods (1) joined at the centre of their longitudinal axis allowing the swivel motion of rods, at least part of which have bore-holes (2) at each end for enmeshing hinge-pins forming part of pins bent at a definite angle (3) and hinges (4) constituting jointly interconnecting pieces (E) so that the paired rods are joined with the similarly assembled paired rods and the interconnecting pieces to form a lattice of at least three paired rods arranged in sequence , and the paired rods arranged in sequence are joined by means of interconnecting pieces to form a stiff frame under the angle of plane of the paired rods characterized in that the ends of at least a part of paired rods (1) are joined by hinges (4) the middle axis of which is unidirectional with the longimdinal axis of the frame structure, further actuator (5) responsible for expansion / contraction, actuator (6) responsible for tilting, both actuators used for power transmission, swivels (7) joining the two bottom corners of one end of the frame and the bearer base approaching each other at the expansion of the bridge in a direction perpendicular to the travel of the latter and moving away from each other at pull-in and the supplementary subassemblies of the bridge structure allow the controlled travel of the latter. 2. The structure of Claim 1 characterized in that the bridge comprises deck (8) comprising typically rectangular corrugated sheets joined by at least part of mterconnecting pieces (E) capable of moving together with the bridge structure. 3. The structure of Claim 1 and Claim 2 characterized in that the bridge structure and the bridge deck (8) typically fastened to the former is built typically onto the platform (10) of a truck designed for road transport (9) equipped with outriggers (11). 4. The structure of any of Claims 1 through Claim 3 characterized in that the paired rods (1) constitute a frame structure in the form of an isosceles triangle without hinge (4), provided the statics conditions allow it. 5. The structure of any of Claims 1 through Claim 4 characterized in that the structure comprises roller bed (12), bearer rail (13) and slide (14) fastened to the platform joining the bottom middle nodes of the rows of rod pairs assuring jointly as constraint paths the stability of travel of the emergency bridge. 6. The structure of any of Claims 1 through Claim 5 characterized in that the bridge structure comprises wire rope (15) for stiffening the characteristic slightly vaulted structure of the bridge and damping the sudden variations of speed at push-out and lowering, hoist (16) or other supplementary devices facilitating the actuation thereof. 7. The structure of any of Claims 1 through Claim 6 characterized in that the cross section and loading capacity of rods (1) placed closest to the driver's cabin of truck (9) is higher due to the varying load. |
The subject of the invention is a mobile emergency bridge structure designed especially for carrying by motor vehicles.
A solution similar to the subject of this invention is patent specification N° HU P 04 01242 entitled "Mount structure especially for mobile rapid deployment mount" registry M° 226 315; the inventor is the applicant of this invention.
The document referred to above describes a mount structure having sides assembled of scissor-type paired rods. According to the patent specification the three sides are united by band joints so that the three sides may be folded onto each other, thus making the structure transportable. For the variability of design the mount structure may consist of two to four side panels.
The invention entitled "Mobile emergency bridge" featuring an operational model and favourable presentation experience is the technically upgraded version of invention N° HU P 04 01242. The patent application for invention was submitted to the Hungarian Patent Office on 3 rd November 2009; the HPO recognized this date as a date of application. The report on the search for existing patent rights carried out by HPO and the additional written comments thereto cite the following documents: Dl : HU 226 315 Bl (see above); D2: US 4,628,560 Al; D3: GB 534,913 A; D4: CN 201187307 Y; D5: US 5,117,525 Al .
Document D2 (a foreign patent found by the search for existing patent rights to be the closest to the design proposed in the application) exhibits a pantograph bridge structure transported to the desired location on a vehicle (a trailer). The trailer is equipped with all the devices required for erection such as (telescopic) lift frame, wire ropes, hoist and hydraulic power cylinder. According to the specification of document D2 the erecting masts for the wire ropes are erected at both bridge-heads after the spragging of the carrier trailer, then the pantograph bridge structure is rigged up; then the scissor-type frame structure is expanded by means of the wire ropes and hoists. According to the specification the preferred embodiment is used for bridging distances from 15 to 30 m. The expanded bridge structure consists of an inverted triangular pantograph; the gangway is laid on the top side.
Document D3 describes a foldable scissor-type truss girder bridge structure. The bridge structure is of U-shaped section providing and integrated truss girder for the gangway. Instead of the bisecting points the scissor-type paired rods are joined in an asymmetric fashion creating the bridge structure shown in Figure 1 of D3.
In document D4 a structure used as a canopy at the entrance of shopping malls or at constructions sites is described. The model relates to a drawing driving ring-shaped supporting frame type combined scissor expansion / contraction pushing mechanism, particularly to a ring-shaped supporting frame type combined scissor expansion / contraction pushing mechanism drawn and driven by a travel cable and a pulley. The ring-shaped frame type combined scissor expansion / contraction pushing mechanism comprises a plurality of ring-shaped supporting frames, wherein the roller wheels or the slippers at the bottom of the ring-shaped supporting frames are arranged in sequence on a ground rail or a smooth road; and a plurality of scissor arrays, wherein the scissor rod connecting point loops of the scissor arrays are arranged in sequence inside the scissor array mounting grooves on the lateral sides of the ring-shaped supporting frames and connected. The power unit pulls and draws the travel cables to produce the power, and the power is transferred by the pulleys to move scissor arrays, thereby changing the scissor included angles, driving the ring-shaped supporting frames to move along the ground rail or the smooth road, and achieving the expansion / contraction pushing effect, as shown in the figures of the document.
Document D5 describes a take-apart drive-over bridge structure of low silhouette transported by a special vehicle to the far bank. The bridge structure is assembled on the vehicle and then the cantilever of two halves slides over the obstacle to be bridged. The bridge structure consists of two preassembled pieces lifted into final position in a separate phase of erection.
It is to be noted that, among the patents reviewed in the course of search for existing rights, several include structures similar to the one used in another upgrade of the subject of document ½ HU 226 315 Bl referred to above, such as FR 2 577 584 Al, US 4,126,974 A1,JP 2002 351337 A); these comprise foldable, transportable truss structures designed for lifting upwards. These structures can be used in the oil industry, movie shootings, integrated hoists, geodesic and other photographing jobs, or perhaps, in a secondary mode of application, as components of light bridges.
The essence of structure forming the subject of this invention is not the so-called lazy tong system consisting of several paired rods arranged in sequence in fixity contracting in a scissor-like fashion, and neither do the claims highlight this as a novel special feature. The fundamental purpose of the mobile emergency bridge is to bridge, in the shortest possible time, a relatively large distance from the truck's platform or another suitable foundation designed to carry the full load of the expanded bridge structure.
Of the patents reviewed as part of the search for existing rights the approximately 1 : 16 ratio of the lifted height to the distance between the base and the apex of the usually regular triangle of the base figures only in the case of some vertically collapsible masts featuring a stable base. None of the examples referred to, however, features the same ratio and the same capability under entirely different conditions of statics in near-horizontal position, without bearer cable and on-site assembly. The bridge structure pushed out from the vehicle's platform can travel in the air without propping yet be kept under control. Though an abutment is required for use after the expansion of the structure the same as in the case of any other bridge, yet it is not indispensable during the operation of expansion, and the bridge structure may rest on any footing across the obstacle bridged such as built structures, provided such footing is above the level line.
None of the devices mentioned above proposes the special assembly quoted in the first claim as the characteristic feature of the invention, namely that both bottom endpoints of the bridge structure are hinged to the vehicle's platform in such a manner that the hinges can approach each other during expansion. (The method used in the model is that one hinge is fixed to the platform and the other may approach the former by sliding along skate fastened to the platform as shown in Figures 5 and 6. Obviously the mutual approaching of hinges can be assured by means of special rollers running along rails integrated in the platform, or by other means.
Another unique feature is the absence of a component corresponding to the tilting actuator of the transmission chain of the bridge structure for the lifting of erect collapsible masts and mounts, because no tilting takes place in the process of lifting. Lifting, or its horizontal counterpart, expansion, is carried out typically by the use of more complex structural components such as threaded rods rather than the actuator producing horizontal thrust at a sole point of application as specified in this invention. In Figure 5 of bridge structure specified in D2 the option of overturning applies to the alignment of the frame for expansion rather than the controlled tilting of the partly pushed out bridge structure.
The third special feature of this invention that transcends the known patents and discerns it from those is that for better use of space and higher strength it allows the use of a frame structure in the form of an isosceles triangle instead of a regular triangle using hinges aligned with the longitudinal axis of the structure. In the following the purpose and description of the mobile emergency bridge is summarised by the use of references.
There are bridge structures of varying loading and bridging capacity known in military and disaster recovery practice. The preliminary survey conducted by experts having extensive knowledge of the available choice of temporary bridges showed a gap in the choice of rapid deployment bridges of 20 to 40 m bridging capacity and relatively lower loadability, which would be an efficient solution based on the experience of the past years, particularly in the recovery after natural disasters.
The invention proposes a rapid deployment solution for an emergency bridge of 30 m to 40 m bridging capacity for the passage of persons, two-wheeled vehicles, light equipment and domestic animals designed for carrying without special road permits by truck.
The structure of the emergency bridge consists of scissor-like paired rods 1 connected in the middle by spindle - a solution well-known from the everyday practice. The special feature of the solution is that the scissor-like paired rods are arranged in a triangle shape so that the joining of ends of three scissor-like paired rods with interconnecting pieces E through boreholes 2 constitutes a triangle-shaped element wherein the sides of paired rods 1 open in a scissor-like fashion. By joining the triangle-shaped elements a structure expanding and contracting in a direction orthogonal to the section of the triangle of 15 to 30 ratio of expanded to contracted height (depending on dimensioning) is created. (It means that the contracted length of the light bridge structure of e.g. 20 m bridging capability can be as little as 1.2 m).
It follows from the specific system of scissor-like paired rods that the orthographic angle between the paired rods does not change during opening and closing, and its value always remains 60 degrees, provided the length of paired rods is identical on all three sides. This feature allows the creation of stiff corner joints of interconnecting pieces E comprising two fixed spindles 3 axle enclosing a 120 degree angle. The ends of connected rods rotate around the two spindles.
If, for reasons of stability or for practical considerations, a structure in the shape of an isosceles rather than regular triangle is created, then the scissor-like paired rods ends need to be joined with each other by hinges 4 the spindle of which is unidirectional with the longitudinal axis of the structure. This is necessary because the orthoscopic angles defined in the plane orthogonal to the longitudinal axis of the structure become distorted during the opening and closing of the structure, so the structure would become stuck if stiff connection joints were used.
In expanded (open) condition the resistance of the structure against bending and torsion stress is rather significant.
In order to commission the bridge structure it needs to be delivered on site, expanded and buttressed. Since the contracted bridge structure fits on properly modified platform 10 of truck 9 so that the dimensions of the truck do not exceed the travelling space on public roads, the emergency bridge can be delivered on site by truck.
The two bottom corners of one end of the triangular bridge structure are connected to the modified platform of the truck by means of joints 7. The characteristic feature of the structure is that during the expansion of the bridge these joints approach each other. Accordingly, either one or both bottom joints on the platform of the truck must be allowed to travel axially, in a direction perpendicular to the expansion travel of the bridge structure. On the completed model one of joints 7 travels along slider 14 in axial direction.
The first step in the installation and operation of the bridge is that the carrier truck is orientated for correct incidence angle and direction; then the truck is anchored using outriggers 11 well known from practice. The incidence angle interpreted here as the angle enclosed with the horizontal plane is important, because the bridge structure can be tilted upwards by approximately 30 degrees and downwards by 12 degrees relative to the plane defined by the base points of wheels of the truck. This means that if the bridge needs to be positioned just about horizontally and, considering the natural sag of the long bridge structure, the incidence angle of the truck may be in the 0 to 15 degrees range relative to the horizontal plane. The direction of the truck is important because it determines the direction of the longitudinal axis of the bridge structure.
The second step in the installation of the bridge is to lift the structure by means of actuator 6 designed to tilt the bridge structure through power transmission. It is important to note that the actuator is fitted with bearings allowing rotation relative to the truck's platform so during the expansion of the bridge structure the transversal travel of one corner of the structure mentioned earlier causing the rotation of actuator connected in the centre-line of the structure does not bring about the seizing of the structure. The third step in the installation of the bridge is to push out the free end of the structure above the chosen bridgehead by the use of actuator 5 designed for expansion / contraction. Roller bed 12 facilitating the movement of components of the expanded bridge structure is designed to prevent the wear of stainless steel rail 13 fitting into the lower part of the platform exposed to frictional stress caused eventually by the natural sag of the bridge structure between the protruding part of the actuator and the bottom surface of the lower rods.
In order to keep the travelling of actuator 5 designed for expansion and contraction always along the centre-line of the bridge, one end of the actuator can be connected to the middle spindle of the front bottom scissor-like paired rods falling towards truck 9, and the other end of the actuator to the middle spindle of the second or third bottom scissor-like paired rods falling towards the truck.
The fourth step in the installation of the bridge is to lower the end of the structure onto the chosen bridgehead. In this manner the bridge rests on the platform of truck standing on outriggers 11 and the chosen bridgehead. An interesting option is that the eventual loading capacity of the structure introduces less risk during installation and mainly in the use of the bridge on the one hand, and on the other hand the bridge keeps its vaulted (or arched) shape following from the natural sag affecting favourably the load capacity of the bridge.
Passage across the bridge structure is assured by deck 8 consisting of preferably corrugated uniform sheets joining the hook fastened to the rod of bridge structure 5 farthest from the actuator. The corrugated sheets joined by wire cable or similar bonding unit overlapping fully in contracted condition and slightly after expansion cover the bottom paired rods arranged in sequence along the entire length of the expanded bridge. Wire ropes 15 provide stiffening of the bridge, facilitate the rapid forward movement and braking of components of the vaulted structure.
The engine of truck 9 placed in front serves as a counterweight that helps balancing the extended and not yet buttressed bridge. If the counterweight constituted of engine is insufficient, additional counterweights must be fixed to the front of the truck.
In extended condition of the bridge structure the angle enclosed between the rods of the scissor-like paired rods is usually between 120 and 60 degrees, where the former belongs to the shorter expansion span and the latter - to the longer expansion span of the bridge. Obviously these angles may be higher than 120 degrees at shorter expansion span, but in this condition the capacity utilization of the structure is low. At longer spans of expansion the angle enclosed between the rods of scissor-like pairs can be less than 60 degrees at the cost of a considerable decrease in the stability of the bridge.
During the expansion of the bridge the structure takes a load similar to a clamped beam so the loading of rods nearer to the truck is higher; for this reason the design of a structure of uniform strength wherein the cross-section of rods nearer to the truck is bigger is preferable. In this manner the dead weight of the structure can be minimized. Rods of higher load capacity are required at the connecting points of tilting actuators 6 and pushing actuators 5, because along with the dead weight the structure is under higher pinpoint load at these locations. The tilting and pusher actuators are preferably hydraulic cylinders, but they can also be screw-spindle units.
The invention is discussed in detail below based on functional examples and drawings.
Figure N° 1: Perspective view of the expanded and lifted mobile emergency bridge. Note that the frame structure of the bridge is constituted of a row of rods consisting of paired rods 1. The frame supported by open actuator 5 responsible for expansion / contraction is held together by couplers E. Note also that the frame structure slightly vaults onto the far bank across the vehicle.
Figure N° 2: Side view of the collapsed mobile emergency bridge, with the bridge structure tilted. Note the key components moving and keeping aligned the structure.
Figure N° 3: Front view of the carrier vehicle
Figure Na 4: Top view of the mobile emergency bridge, including wire cable and hoists.
Figure Ns 5: Rear view of the bridge structure on the platform with the hinges and skate; the vehicle is spragged.
Figure N2 6: : Rear view of the bridge structure on the platform showing the frame structure in the form of an isosceles triangle, the hinge and the ladder.
Figure JV° 7: View of the bridge structure showing the expansion / contraction actuator, roller bed and stainless steel rail
Figure N° 8: Side view of the expanded mobile emergency bridge showing the deck components all along the structure Figure N° 9: Corrugated sheet components of the gangway in a possible embodiment of the bridge structure.
The application options of the mobile emergency bridge offer a number of advantages. The frame structure alone would be sufficient for bridging over to the far bank, yet the equipment complete with the deck moving smoothly along and allowing anchoring on the far bank offers means for facilitating practical disaster recovery and rescue operations e.g. by joining the second floor or balcony of a building affected by fire, flooding, mud, etc. The stiffening of the entire structure is feasible using wire ropes drawn by hoists below or above the bridge deck; inside the frame special containers or trolleys can be moved back and forth by the alternating motion of two wire ropes. Not unlike any other type of special bodywork trucks the combined bridge structure can be redirected to other sites of emergency operations upon the completion of the job. By reversing in the yard of buildings accessible via flooded or otherwise dangerous roads the carrier truck can lower, literally in a matter of minutes, the fully assembled bridge onto various points of the affected building.
Obviously the fields of application of the invention are not limited to the design versions and examples demonstrated in the drawings. For optimum use a number of changes may be introduced in the course of the development process that still fit into the frame of the invention yet satisfy the needs of other areas, such as building and construction industry, military applications, communication, water economy, etc. The advantages mentioned above allow the user to save on the excess cost of special equipment, such as truck crane and other special technical vehicles.
The scissor-like rods of the mobile emergency bridge structure can be made of steel or light metal alloy, or reinforced polymer such as synthetic materials and resins reinforced with carbon-, glass- or kevlar fibre. Legend for mobile emergency bridge
1. Paired rods
2. Bore-hole
3. Bent shaft
4. Hinge
5. Actuator for expansion and contraction
6. Actuator for tilting
7. Swivels
8. Bridge deck
9. Truck
10. Platform
11. Outriggers
12. Roller bed
13. Rail
14. Slide
15. Wire rope
16. Hoist
E Fastening unit
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