Bridge element

Abstract: A bridge element for an army bridge comprising two parallel track lanes (10, 11), a framework structure carrying said track lanes, and coupling devices (15, 16, 70) for connecting a plurality of bridge elements sequentially to form a row. The framework construction includes a first section (12) with track lanes (10) a second section (13) with ramp track lanes (11); and a third section (14) which connects the first and the second sections together. A longitudinally extending space (42) formed beneath the track lanes and has the form of an inverse V with a truncated apex. The first section is identical with the second section. The characteristic feature of the invention is that said framework construction is a welded non-collapsible construction wherein each first and second sections comprises, a pair of parallel, longitudinally extending bottom beams (30, 31) spaced apart a short distance in a first plane; a triplet of top beams (33, 34, 35) with two outer beams (34, 35) and a central beam (33), arranged in a second plane located above the first plane, said top beams being parallel and spaced apart at a somewhat larger distance than the bottom beams; pairs of vertically mounted struts (37, 38) extending between the two bottom beams and the two outer beams of the beam triplet, to form a V-shape; and vertical diagonal struts (32) extending between the bottom beams (30, 31).

Description: The present invention relates to a bridge element for the construction of a multispan military or army bridge. Many different requirements can be placed on a military bridge. For instance, it must be possible to construct and lay the bridge quickly under field conditions with the use of the minimum number of workmen, and it must also be possible to transport the bridge construction kit easily to the site at which the bridge is to be layed. Among other things, these requirements have resulted in the construction of military bridges from readily transportable lightweight aluminium-beam frameworks which can be carried easily by personnel. Such aluminium frameworks, however, tend to become particularly complicated, due to the requirements placed on the load bearing capacity of the finished bridge. Consequently, a military or army bridge constructed from aluminium in this way is expensive to produce. German Patent Specifications 2 540 267 and 2 812 531 teach collapsible beam structures for use in the construction of military bridges. Each beam comprises plates which are mutually joined together by means of dovetail couplings formed in the plates. Two such beams are placed adjacent one another and connected together with the aid of cross-struts, to form a bridge element. A plurality of these bridge elements are joined together in a row, with the aid of bolts which extend between blocks mounted on the side-walls of each beam. The drawback with these known constructions is that it takes a very long time and the use of a large number of men to assemble the beams and then to join the beams together to form a bridge element and then to couple the bridge elements together in a row to form a bridge. The British Patent Specification 2 038 391 illustrates an example of a military bridge which consists of one single span and which is carried on a special-purpose vehicle. The drawback with the use of such special-purpose vehicles for transporting military bridges is that the vehicle can only be used for its intended purpose, i.e. to transport military bridges. One object of the present invention is to provide a bridge element of framework construction, made of steel, and having a high load bearing capacity such as to enable several bridge elements to be joined together in a row and therewith form a cantilever construction. This object is achieved with a bridge element of the kind defined in the following Claim 1. Yet another object of the invention is to provide a bridge element having coupling devices for connecting several bridge element together in a row. Other characteristic features of the invention are set forth in the depending Claims. The invention will now be described in more detail with reference to the accompanying drawings, in which Figure 1 is a perspective view of a bridge construction kit; Figure 2 is a perspective view of a bridge under construction; Figure 3 is a side view of an inventive bridge element; Figure 4 is a top view of the bridge element shown in Figure 3 and is taken on the line IV-IV in said Figure; Figure 5 is a longitudinal sectional view taken on the line V-V in Figure 3; Figure 6 is a cross-sectional view of the bridge element shown in Figure 4 taken on the line VI-VI in said Figure; Figure 7 is a sectional view similar to the view of Figure 4, and shows a first type of coupling device for coupling two bridge elements together; Figure 8 is a side view, in larger scale, of a first type of coupling lug; Figure 9 is a side view taken on the line IX-IX in Figure 7 and illustrates a second type of coupling lug, on a larger scale; Figure 10 is a side view, partially in section, of a second type of coupling device for coupling two bridge elements together; and Figure 11 is a front view, partly in section, of the coupling device illustrated in Figure 10. Figure 1 illustrates a bridge construction kit comprising a number of bridge elements 1, in accordance with the present invention. The kit also comprises two ramp sections 2 of a first kind, two ramp sections 3 of a second kind, a crane carriage 4 having a hydraulic lifting arm or jib 5, pairs of support legs 6 and, when very long bridges are to be constructed, a bridge element shuttle. The various components of the construction kit are transported on conventional trucks 8 provided with trailers 9. Suitably, at least one truck is equipped with a hydraulic lifting crane, as illustrated with the vehicle shown at the bottom of Figure 1. The components can be lifted from the trucks by means of a conventional tractor fitted with lifting forks, as illustrated in Figure 2. It will be seen from Figure 1 that each bridge element 1 and each ramp section 2, 3 includes two mutually parallel track lanes 10, 11. The bridge elements 1 and the ramp sections 2, 3 are framework constructions and include a first section 12 which supports the one track lane 10, a second section 13 which supports the other track lane 11, and a third section 14 which connects the first and the second sections together. The bridge elements 1 and the ramp sections 2, 3 are provided with coupling devices which enable the bridge elements to be connected one to the other and also to the ramp sections. These coupling devices also enable a ramp section of the first kind to be connected to a ramp section of the second kind. The coupling devices are shown schematically at reference numerals 15 and 16 in Figure 1. The coupling devices are provided at each end of respective bridge elements 1 and ramp sections 2, whereas coupling devices are only provided at one end of respective ramp sections 3. Figure 2 illustrates the procedural steps taken when laying a multispan bridge. In the illustrated case, several bridge elements 1 have earlier been connected mutually to form a long line. The outermost bridge element is referenced 20 and the innermost 21. The crane carriage 4 has lifted a bridge element 22 over the track lanes 10, 11 and is in the process of transporting the raised bridge element 22 to the outermost bridge element 20. Meanwhile, the tractor or truck crane has lifted a further bridge element 23 onto the innermost bridge element 21. When the crane carriage 4 has reached the bridge element 20, it lowers the bridge element 22 onto this outermost bridge element and reverses slightly, so that the lifting arm 5 is freed and able to raise the bridge element 22 slightly. The crane carriage 4 is then driven forwards somewhat and the bridge element 22 is lowered so that its coupling devices can be connected to corresponding coupling devices on the bridge element 20. The coupling devices are then locked with the bridge element 22 supported in cantilever fashion. A plurality of bridge elements can be connected together in a cantilever fashion in this way, before needing to support the bridge with a leg support pair 6. The spacing between two such support leg pairs 6 is called a span. The length of a span depends, among other things, on the load acting on the bridge, and can vary. A bridge element 1 will now be described in more detail with reference to the accompanying Figure 3-5. The first section 12 is identical to the second section 13 and consequently only the first section 12 will be described in detail. The first section comprises a pair of mutually parallel longitudinally extending bottom beams 30, 31 which are mutually spaced at a short distance apart in a first plane. The mutually facing inner surfaces of the bottom beams are welded firmly to the bottom end of struts or braces 32 which extend vertically in the cross-section of the bridge element and, in the longitudinal section of said element, extend diagonally between the bottom beams and a central beam 33 located thereabove, this central beam being described in more detail herebelow. The central beam is thus supported by the struts 32. Located in a plane above the first plane is a triplet of top beams, comprising two outer beams 34, 35 and the aforesaid central beam 33. The top beams 33, 34, 35 of said beam triplet extend parallel to one another and the spacing between said beams is greater than the spacing between the mutually parallel bottom beams 30, 31. Mounted on the upper surface of respective top beams 33, 34, 35 is a track lane 10, which includes a bottom plate and an upstanding side verge 36. The outer beams 34, 35 are supported by pairs of outer struts 37, 38. The outer strut 37 extends from the bottom beam 30 to the outer beam 34, whereas the outer strut 38 extends from the bottom beam 31 to the outer beam 35. Seen in the cross-section of the bridge element and in those directions shown in Figure 6, the outer struts 37, 38 form a V-shape, and seen in the longitudinal section of the bridge element, the outer struts 37, 38 are vertically upstanding as illustrated in Figure 3. The third section 14 is located between the first and the second sections 12, 13 and includes a plurality of cross-beams 39 which are arranged at regular intervals along the length of the bridge element. These cross-beams 39 extend transversely to the longitudinal extension of the bridge, between the adjacent outer beams 35 of the first and the second sections 12, 13, and are welded thereto and also to bracing plates 40. Seen in top view and in the directions shown in Figure 4, the outer struts 37, 38 are in line with a cross-beam 39. A brace plate 40 extends between the upper part of the outer strut 38 and the cross-beam 39. As will be seen from Figures 6 and 4, additional brace plates 41 are disposed between the inner surface of the outer struts 37 and 38, in the upper part thereof. The upper parts of respective brace plates 41 are welded to the top beams 33, 34, 35, in the manner illustrated in Figure 6. The whole of the framework construction is welded and comprises steel plate beams. According to one preferred embodiment of the invention, each bridge element has a length of about 8 m, a width of 4 m and a vertical extension or height of about 1.5 m. Each track lane has a width of about 1.8 m. As will be seen from Figure 6, and also to some extent from Figure 1, there is formed between the first, second and third sections a longitudinally extending space, indicated by the broken line 42 in Figure 6, which in cross-section has the shape of an inverse V with a truncated apex. When seen in the longitudinal direction of the bridge element, this space is free of all obstacles and will enable the crane carriage 4 or the shuttle to be driven in beneath the bridge element, in order to lift and transport said element. In the case of the bridge element illustrated in Figures 3-6, the top beams 33, 34, 35 lie in a plane which is parallel to the plane in which the bottom beams 30, 31 lie. In the ramp section 3 of said second kind, the plane in which the top beams lie is inclined relative to the plane of the bottom beams. In the ramp section 2 of said first kind, the top beams lie in a plane which is common to said top beams, whereas the bottom beams 30, 31 are angled in the illustrated fashion, so as to lie in two mutually different and mutually parallel planes, which are also parallel with the plane of the top beams. It will be seen that the ramp sections 2 and 3 will function as drive-on and drive-off ramps at both extremities of the bridge. Two bridge elements are connected together by means of coupling devices comprising a first coupling type 15 and a second coupling type 16. The coupling devices of the first type 15 are provided at respective end surfaces of the top beams 33, 34, 35, whereas the coupling devices of the second type 16 are arranged at the end surfaces of the bottom beams 30, 31. The first type of coupling device 15 is a male and female coupling, as is also the second type of coupling device 16. The female part of the coupling device 15, 16 is mounted on one and the same end of the bridge element, whereas the male part of the coupling devices 15, 16 is mounted on the opposite end of said bridge element. Thus, the bridge element will have a male coupling side and a female coupling side as illustrated in Figures 3 and 4 respectively. The first type of coupling device 15 includes an upstanding coupling lug, whereas the second type of coupling device 16 includes a coupling tongue. The coupling devices on the male side of a bridge element are intended to fit into the coupling devices on the female side of another bridge element. As will be seen from Figures 3, 4 and 8, each first type of coupling device on the male side of the bridge element has a coupling lug 50 which is on a level with one side surface of the outer beam 34 and another coupling lug 51 which is on a level with the opposing side surface of the same outer beam. Correspondingly, pairs of such lugs 50, 51 are mounted on the remaining central beam 33 and outer beam 35 of the beam triplet. A number of female coupling lugs 52, 53, 54, 55 are mounted on the female side of the bridge element. The coupling lugs 52, 53 form pairs of lugs which are intended to receive a male type coupling lug 50 therebetween, whereas the coupling lugs 54, 55 form another pair of lugs which are intended to receive the coupling lug 51 therebetween. Correspondingly, each of the remaining top beams of the beam triplet is provided with quartets of female-type coupling lugs 52-55. The coupling lugs 52, 53 are displaced in relation to the side surface of the outer beam 34, whereas the lugs 54, 55 are displaced relative to the opposite side surface of the same outer beam 34. All of the lugs 50-55 comprise metal plate pieces which are welded to the side surfaces of the top beams. The male-type coupling lugs 50, 51 have a through-passing opening 60 formed therein, as illustrated in Figure 8, and the female-type coupling lugs have a corresponding through-passing opening 60 and, in addition thereto, a through-passing opening 61 and an elongated third opening 62 passing through the plate and connecting the opening 60 and 61 together. The lugs 52, 54 on the female side are also provided with a guide annulus which surrounds the opening 60 and has an axially extending slot 64. As a preparatory step before connecting two bridge elements together, a locking rod 70, shown in Figure 7, is inserted through the opening 61 on the female-type coupling lugs. The locking rod has welded thereto a number of dogging elements 71, 72 which project radially from said rod at mutually the same angular position thereon, in other words the dogging elements 71, 72 are in line with one another. Mounted on the end of each dogging element 71, 72 is a locking pin or stud 73. The arrangement is such that the locking pin 73 projects into the guide annulus 63 and through the thickness of the coupling lug 52 and 54 respectively. Thus, the end surface of the locking pin 73 will lie on a level with an end wall surface 74 of the lug 52. The end surface of the locking pin 73 on the dogging element 72 is also on a level with a corresponding end wall surface 74 of the lug 54, at the same time as the spine part of the dogging element 72 lies within the opening 60, 61 and 62 on the lug 53. The dogging elements 71 comprise metal-plate pieces whose thicknesses correspond to the width of the elongated opening 62. In preparation to coupling to bridge elements together, the locking rod 70 is inserted through the opening 61 in the female-type coupling lugs, wherewith the dogging elements 71, 72 and the locking pin 73 pass through the opening 62 and 60 respectively. The position of the locking rod 70 is then adjusted to the position shown in Figure 7. When the male coupling lugs 50, 51 of another bridge element have been inserted between the female coupling lugs and have been adjusted so that the openings 60 on the lugs 50, 51 register with the opening 60 on the lugs 52-55, the bridge elements can be locked together. This is effected by pushing the rod 70 in the direction of the arrow 75 in Figure 7, wherewith the locking pins pass completely through the opening 60 in the lugs 50, 51 and also project slightly into the wall of the lugs 53 and 55 respectively. This results in stable connection of the bridge elements. When two bridge elements have been mutually connected in this way, the outermost bridge element can be swung around the centre line 76 of the locking pins 73 to a position in which the second kind of coupling devices 16 on the male side of the outermost bridge element are swung into the second type of coupling devices 16 on the female side of the stationary bridge element. The coupling devices 16 of said second kind have a conical configuration reminiscent of a conventinal paper hole punch. The male side (Figure 3) consists of a coupling tongue 80 in which a number of through-passing openings 81 are formed, in the illustrated embodiment four openings 81 (Figure 5). The coupling tongue 80 is welded to the bottom beams 30, 31 with the aid of mounting plates 82, 83 welded respectively to the top and bottom surfaces of the bottom beams. Similarly, two coupling tongues 84, 85 (Figure 3) are mounted one above the other on the female side of the bridge element. These tongues 84, 85 also have a row of openings 81 formed therein (Figure 5), in the illustrated case four such openings, which are located vertically one above the other in the two coupling tongues 84, 85. These tongues 84, 85 also consist of metal-plate elements which are welded respectively to the top and bottom sides of the bottom beams 30, 31. The vertical extension of the space between the tongues 84, 85 corresponds to the vertical extension of the tongue 80. The upper tongue 84 has mounted thereon a number of locking pins or studs 87 (Figures 10 and 11) and a holder 88 for holding the locking pins in a vertical position. The holder 88 is in the form of a housing which comprises a top wall 89, end walls, side walls and an elongated guide plate 90 provided with guide openings 91 disposed vertically above the openings 81. Each locking pin 87 coacts with an activating means 92 mounted on the top wall 89. The activating means 92 is preferably a hydraulic piston-cylinder unit, the piston rod 93 of which is fastened to the locking pin 87. The locking pins 87 can be moved between an upper, open position, shown in full lines in Figure 11, and a lower, locked position in which the pins extend through the openings 81 on the male coupling tongue 80 and also through the openings 81 on the lower coupling tongue 85. Provided in the region where the locking pin 87 is connected to the piston rod 93 is a rod 94 which passes through the top wall 89 and which accompanies movement of the locking pin. This rod serves as a visual indication that the pin has truly taken its lower locked position. One such rod 94 is provided for each locking pin 87. It will be understood that the aforedescribed embodiment of the invention can be modified and varied in many ways within the scope of the following Claims.

Claims: A bridge element (1, 2, 3) comprising two mutually parallel track lanes (10, 11), a framework structure carrying said track lanes, and coupling devices (15, 16, 70, 87) for connecting a plurality of bridge elements sequentially to form a row, wherein said framework construction includes: i) a first section (12) which carries one of said track lanes (10); ii) a second section (13) which extends parallel to the first section and carries the other of said track lanes (11); and iii) a third section (14) which connects the first and the second sections together; said third section comprising a plurality of cross-beams (39) which extend transversely between the first and second sections (12, 13) such as to form a longitudinally extending space (42) which is located beneath the track lanes and which, in section, has the form of an inverse V with a truncated apex; said first section being identical with the second section, characterized in that said framework construction is a welded non-collapsible construction wherein each first and second section comprises: a pair of mutually parallel, longitudinally extending bottom beams (30, 31) which are spaced a short distance apart in a first plane; a triplet of top beams (33, 34, 35) which consist of two outer beams (34, 35) and a central beam (33), arranged in a second plane located above the first plane, said top beams being mutually parallel and spaced apart at a somewhat larger distance than the bottom beams; pairs of vertically mounted struts (37, 38) which extend between the two bottom beams and the two outer beams of the beam triplet, to form a V-shape; and vertical diagonal struts (32) which extend between the bottom beams (30, 31) and connect these bottom beams together and to the central beam (33) of the beam triplet. A bridge element according to claim 1, characterized in that the plane in which the top beams (33-35) lie is parallel with the plane in which the bottom beams (30, 31) lie. A bridge element according to claim 1, characterized in that the bottom beams (30, 31) are angled so as to lie in two mutually parallel planes which are located on different levels and which are parallel with the plane of the top beams, therewith to form a ramp section (2) of a first kind. A bridge element according to claim 1, characterized in that the plane in which the top beams lie is inclined to the plane in which the bottom beams lie, therewith to form a ramp section (3) of a second kind intended to form a drive-on and drive-off ramp. A bridge element according to claim 1, characterized in that said coupling devices include: a first array of coupling lugs (50, 51) mounted on those end surfaces of the top beams (33-35) of said beam triplet which are located at one end surface of the bridge element, such as to form a male side on said element; a second array of coupling lugs (52, 53, 54, 55) mounted on those end surfaces of the top beams of the beam triplet which are located at the opposite end surface of the bridge element, such as to form a female side on said element; wherein a coupling lug (50) on the male side of a bridge element is intended to fit between two coupling lugs (52, 53) on the female side of another bridge element, and a locking rod (70) provided with a plurality of locking pins (73) for locking the first array of coupling lugs (50, 51) of a first bridge element to the second array of coupling lugs (52, 53, 54, 55) of a second bridge element by pushing said locking rod. A bridge element according to claim 5, characterized in that each coupling lug (50-55) includes an endwall plate which is vertically upstanding from the end surface of each top beam and which is provided with a through-passing first opening (60). A bridge element according to claim 6, characterized in that the coupling lugs (52-55) on the female side are mutually parallel and spaced apart at a distance corresponding to the thickness of a coupling lug (50, 51) on the male side and at a position in which they can receive a coupling lug on the male side of another bridge element. A bridge element according to one or more of claims 5-7, characterized in that said locking pins (73) are mounted on a respective dogging element (71); in that each dogging element has a first and second end; in that the first ends of the dogging elements are welded to the locking rod such that the dogging elements will extend perpendicularly to said rod and such that all of said dogging elements lie axially in line with one another, in that the locking pins (73) are anchored to the second end of the dogging elements and have an outer contour which corresponds to the contour of the through-passing openings (60) in the coupling lugs (50-55). A bridge element according to claim 8, characterized in that the coupling lugs (52-55) on the female side of the beams of the beam triplet are provided with a through-passing second opening (61) having a diameter which is slightly larger than the diameter of the locking rod (70), and a through-passing, elongated third opening (62) which extends between the first and the second openings, said third opening (62) having a width which is slightly larger than the thickness of the dogging elements (72) so as to accommodate said dogging elements when the locking rod is inserted through the coupling lugs on the female side. A bridge element according to claim 9, characterized in that in each pair (52, 53 and 54, 55) of coupling lugs on the female side, the one coupling lug (52 and 54) is provided with a guide annulus (63) which is placed around the first opening (60) such as to receive and guide a corresponding locking pin on the locking rod, said guide annulus having an axially extending slot (64) through which the dogging elements (71) can pass and are received. A bridge element according to claim 1, characterized in that said coupling devices (16) include: a first coupling tongue (80) mounted on both bottom beams (30, 31) of each section and projecting from said beams on the male side of the bridge element; two second coupling tongues (84, 85) mounted in spaced relationship above one another on both bottom beams (30, 31) of each section (12, 13) and projecting from said beams on the female side of the bridge element; wherein the coupling tongues (80) on the male side are intended to fit between respective coupling tongues on the female side, and hydraulically operated locking means (87, 92). A bridge element according to claim 11, characterized in that the coupling tongues (80, 84, 85) are each provided with a respective row of through-passing (81) openings, in that the upper (84) of the coupling tongues on the female side is provided with said locking means (87); in that said locking means includes a plurality of locking pins (87), a locking-pin holder (88, 90) which holds said locking pins in a vertical position, and a hydraulically operated unit (92) intended for moving the locking pins between an open and locked position, wherein the locking pins in said open position extend partially through solely the openings (81) of the upper coupling tongues (84) and in the locked position extend through said openings (81) in the coupling tongue (80) on the male side of another, connected bridge element and also through the openings (81) in both the upper (84) and the lower (85) coupling tongue.

Inventors: HASSELKVIST ROLF, HASSELKVIST, ROLF
Applicants: KARLSKRONAVARVET AB
Application year: 1991
Main classification: E01D15
IPC codes: E01D15, E01D19