METHOD FOR MAKING A SUPPORTING CROSSBAR CONSTRUCTION AND A CROSSBAR CONSTRUCTION MADE ACCORDING TO THE METHOD

Abstract: An elongated plate is fed in an automatic product line from a plate reel (1a) to a punching station (1b) where elongated plate parts are punched out in at least one central field. The plate parts have a non-broken connection with the adjacent side fields via a plate lap in both ends of each plate part. The edges of the plate parts are then bent so that the plate parts are getting a substantially C-formed profile, making the plate parts rigid. Then, the punched and bent plate is fed further into a circular path (24) and then to a roll-forming station (21, 22) and to a finishing station (23). The final product consists of a crossbar construction (A), where the elongated plate parts are forming the diagonal bars and the side fields the upper and lower frames.

Description: METHOD FOR MAKING A SUPPORTING CROSSBAR CONSTRUCTION AND A CROSSBAR CONSTRUCTION MADE ACCORDING TO THE METHOD The present invention relates to a method for making a supporting crossbar construction and to a crossbar construction made according to the method. More specifically the invention relates to a method for making a supporting crossbar construction of thin plate. US patent 3 034 197 discloses a method for making crossbar constructions from a thin plate reel by cutting elongated slits in the longitudinal direction of the plate and then expanding the plate in the transverse direction. US patent 3 298 081 discloses a similar method for making crossbar constructions as US 3 034 197, however in this case the cutted platebars are bent outwards from the plane of the plate before expanding in the transverse direction. A drawback for the methods according to both these patents is that the bearing strength is low when these constructions are used as crossbar beams. Todays technology for supporting constructions of thin plate, e.g. Dobels light beam and TRP-plate, have the disadvantage that a substantial part of the plate material is not used for the supporting function. Attempts to punch out a light beam to a crossbar with a good supporting capacity means big material losses- and high costs. All crossbar constructions of steel are today made by welding or with bolts. Welding destroys the galvanization and requires a costly subsequent treatment. The present invention is defined in the attached claims. In accordance with the invention the supporting crossbar construction is made from thin plate on a reel, in a contiuously running line with punching and roll-forming machines. Crossbar beams provide a favorable distribution of the material mass into an upper and lower frame, and makes a maximum use of the strength of the material. An advantage of the present invention is that the hight of the new crossbar construction easily can be changed. Bigger beam hight means better bearing strength without increasing the material consumption for the construction. This is an improvement as compared for instance to the previously known light beam. Another advantage of the present invention is that the construction requires neither welding joints nor bolt joints. Still another advantage of the present invention is that the fabrication requires no subsequent treatment. This is especially true when anti-corrosive treated thin plate, such as Aluzinc, is used. Another advantage of the present invention is that very little wastage will be produced and material saving is high as compared to todays technology. Material costs are decisive for the economy in thin plate manufacturing, and in the manufacturing method according ' to the present invention relatively thin plate can be used due to a stiffening bending technic. Due to an automated manufacturing method and low material usage according to the present invention, a highly competitive price for the product can be reached. In the subsequent description three different embodiments of the present invention will be described, whereby three different products are produced, as follows: - a crossbar beam A for light constructions, - a trapezoidal crossbar construction W suitable for joists or roof constructions, and - a crossbar beam B for larger bearing distances. The raw material used is preferably 0,8-2,5 mm steel plate, e.g. Dobels Aluzinc 350 YP, supplyed on reels. The invention will now be described in detail with reference to the accompanying drawings. Fig.l discloses a production line for manufacturing of a crossbar beam for light constructions and a trapezoidal crossbar construction. Fig.2 discloses a punching station in the production line according to fig.l. Fig.3 discloses a station in the production line of fig.l for bending the plate into a circular arc. Fig.4 discloses a first roll-forming station in the production line of fig.l for making a crossbar beam. Fig.5 discloses a further product machining step in the production line of fig.l for making a crossbar beam. Fig.6 discloses a first roll-forming station in the production line of fig.l for making a trapezoidal crossbar construction. Fig.7 discloses assembling of several elements of fig.6 for making a trapezoidal crossbar construction. Fig.8 discloses a production line for making a crossbar beam for larger bearing distances. Fig.9 discloses a punching station in the production line of fig.8. Fig.10 discloses a first roll-forming station in the production line of fig.8. Fig.11 discloses a station in the production line of fig.8 for bending the plate into a circular arc. Fig.12 discloses a second roll-forming station in the production line of fig.8. Fig.13 discloses a turning station in the production line of fig.8. Fig.14 discloses still another roll-forming station in the production line of fig.8. Fig.15 discloses a further product machining step in the product line of fig.8 for producing a crossbar beam for larger bearing distances. Fig.l discloses an overview over a production line for making a crossbar beam A according to a first embodiment of the present invention and for making a trapezoidal crossbar construction W according to a second embodiment of the invention. In a first part 20 of the production line the supply plate is fed directly from a coiling reel la through a punching station or a punching machine lb, where the plate is punched and bent according to a given pattern. From the punching station lb the machined plate is fed to a path 24 forming a circular arc. From the path 24 the plate is fed to a station 21 preferably comprising a roll-forming machine and further to a finishing station 23 to produce a crossbar beam A, as a final product. The manufacturing of the trapezoidal crossbar construction W is started similarily as for the crossbar beam A, by feeding and machinig the plate in the first part 20 of the production line. Then the plate is fed to a roll-forming station 22 and is thereafter worked into a finished product, to be described later. Fig.2 discloses the punching station lb of fig.l, or more specifically the result of punching or cutting and bending the plate in the station. The apparatus for performing the punching and bending is, however not shown. This apparatus may be conventional and does not constitute a specific part of the present invention. In accordance with fig.2 a punching machine or a similar machine has punched or cut out five longitudinal plate fields 2a-2e. In the final product substantially the first and the fifth field 2a, 2e will form the upper frame, the third field 2c the lower frame and the second and fourth field 2b, 2d intermediate diagonal bars. Fig.2 discloses three cutted bars 30-32 in the second field 2b and three bars 33-35 in the fourth field 2d. A bar 30 is made by the punching machine punching or cutting two substantially parallel, longitudinal, line formed apertures or slits 41 and 42 and two inclined transversal slits 43 «_nd 44. This is made such that the bar 30 has an unbroken plate connection via a lap 2f, at the upper slit 43, with the first field 2a, and via a similar lap 2f, at the lower slit 44, with the third field 2c. Then the bar edges 45-48 are bent into a substantially C-profile or similar shape in order to make the diagonal bars rigid. The ends of the longitudinal slits 41 and 42 are so shaped that the laps 2f get a suitable form. Preferably a line drawn between the the upper end point of the slit 44 and the lower end point of the slit 42 will form an angle of 60 degrees with the longitudinal direction of the slit 42. Further, the lower transversal slit 44 of the diagonal bar 30 constitutes the upper transversal slit of the subsequent bar 31. Fig.3 discloses in detail the circular path 24. As shown the plane plate fields 2a, 2e and 2c respectively for the upper and lower frames are curved in a circular arc of 180°. The diagonal bars 30-35, which are rigid due to their C-shaped profile, continue however in their horizontal state, and the joining plate laps 2f are therefore bowed 180° in a line with an angle of 60° towards the upper and lower frame. Section B-B 1:5 in the middle of fig.3 discloses the section B-B in the right half of the figure and the same section in fig.l. Fig.4 discloses the further passing of the plate material through the roll-forming station or machine 21. The two upper frame halfs 2a, 2e and the parallel diagonal bars 2b, 2d are passed in an arc of 90° + 90° to the same plane, however with an opposite inclination for the diagonal bars 2b and 2d respectively. Simultaneously the upper frame plates 2a and 2e are bent into L-profiles 4c and 4b, and the lower frame plate 2c into a T-profile. The sections B-B to E-E correspond to the same sections in fig.l. Fig.5 discloses details made in the finishing station 23. The L-profiles 4b and 4c are folded together into a T- profile 5a. The laps 5b are bent over adjacent plate flanges which are locked in this position. At the ends of the crossbar beam A the lower frame 5d is turned up towards the upper frame 5a. This turning angle defines the desired beam length. The surface of the turning point is reinforced with a plate 5e, which is screwed or bolted to the upper and lower frame. The result will be a statically stable crossbar A. The beginning of the production line for making the trapezoidal crossbar construction W, in accordance with a second embodiment of the invention, comprises the same part 20 of the production line as for the crossbar beam A in the first embodiment shown in figures 1-3. From the circular path 24 the plate material is fed to a roll-forming station 22 according to fig.l, whereby fig.6 discloses the input section H-H and output section I-I for the plate material. In this roll-forming station the lower frame 6a and the two upper frame halfs 6b, 6c are bent into U-profiles 6f, 6g, 6h with the diagonal bars 6d, 6e having an inclination of abt. 60°. Hereby a trapezoidal cross section is formed in which the inclination for the diagonal bars 6d and 6e are opposite in view of the frames 6f, 6h, 6g. A plurality of such elements can be assembled by bolting or screwing together the upper frames as shown in fig.7, forming a stable crossbar construction . The forces in the cross direction of the construction are transferred to steady fastening points or are stabilized by a crossbar or disk material 7a, fastened to the upper frames. Fig.8 discloses an overview over a production line for making a crossbar beam B for larger bearing distances, in accordance with a third embodiment of the invention. Directly from a coiling reel la the plate is fed through a combined punching and bending station lb to a roll-forming station 61, further to a station 62 for bowing the plate into a circular arc and then to another roll-forming station 63. From this station the plate is fed to a turning station 64, then to a further roll-forming station 65 and thereafter to a station for further machining in order to produce the final product B. Fig.9 discloses in detail the result of the punching and bending operations performed in the punching station lb in fig.8. The punching machine has punched or cut longitudinal slits 75 and 76 which devide the plate into three longitudinal plate fields 9a, 9b, 9c. The fields 9a and 9b will form the upper and lower frames whereas the field 9c will form the diagonal bars, of which a first bar 71 and a second bar 72 is shown in the figure. A substantially transverse slit 77 separates bars 71 and 72 from each other. Each bar has an unbroken plate connection to the adjacent plate fields via an upper and a lower lap 9k, equal to the laps 2f in fig.2. The short bar side flanges 9d and a number of auxiliary laps 9e-9i are bent into a suitable angle, as shown in fig. 9-11 and fig.15. Fig.10 discloses the result of the plate material passing the roll-forming machine 61. The diagonal bars are bent into a square C-profile 10a simultaneously with the turnover of the plate fields 9a and 9b abt. 90° into two parallel planes. Fig.11 discloses the feeding of the plate in the substantially circular path 62, see fig.8, so that the angle between the incident line and the outgoing line is abt. 60°. The diagonal bars 71, 72, which are rigid due to their tube formed cross section, follow the original direction of the line. The connecting plate lap 9k is bent 60°. The end laps 9i are bent over the lap 11a to lock the diagonal bars in this position. Fig.12 discloses the plate material path in the new direction through the second roll-forming station 63. The upper and the lower frames are bent into L-profiles 12a, 12b in the various stages, sections L-L, M-M, N-N and 0-0. When the first half of the beam has left the roll-forming station, it is turned 180° in the turning station 64, fig.13, and the diagonal bars are then getting an inclination in the opposite direction. Simultaneously the second beam half is rolling in from the the roll-forming station and is joined with the first half, section P-P. By means of roll-forming in the roll-forming station 65, fig.14 and fig.15, the two halves are folded together into tube profiles with T-flanges, section S-S, T-T and U-U. Finishing of the ends is made in the end station 66 in a same way as for the crossbar beam A, whereby a crossbar beam B for larger bearing distances is produced as an end product.

Claims: CLAIMS 1. Method for making a supporting crossbar construction of thin plate, comprising feeding the thin plate from a reel (la) to a punching station (lb) which punches or cuts bar formed slits into the plate so that a number of parallel plate fields (2a-2e) are formed in the length and moving direction of the plate, said plate fields being then further worked on to form a crossbar construction having an upper and lower frame and intermediate diagonal bars, characterized in that a second plate field (2b) is formed by punching or cutting so that it comprises a number of successive, in the length and moving direction of the plate oriented elongated plate parts (30-32), that each elongated plate part is so punched out from the adjacent first (2a) and third (2c) plate fields respectively, that it is fastened to the first plate field (2a) with a lap (2f) in one end of the plate part and to the third plate field (2c) with a similar lap (2f) in the other end of the plate part, that the edges (45,46) of said plate parts are bent to provide a substantially C-formed or similar profile to the plate parts, that the punched and machined plate is fed further in a path (24) forming a circular arc, where the elongated plate parts, which are rigid due to the C-profile, are not bent similarily as the first and third plate fields, and that a further machining is performed so that the first (2a) and third (2c) plate fields are forming at least parts of the upper and lower frame respectively and the elongated plate parts (30-32) are forming intermediately located diagonal bars of the crossbar construction. 2. A method according to claim 1, characterized in that five parallel plate fields are formed at the punching station (lb), of which said third plate field (2c) is located in the middle with said second plate field (2b) on one side and a fourth plate field (2d) on the other side and with said first plate field (2a) and a fift plate field (2e) as outer fields, that the fourth plate field is formed simultaneously and similarily as the second plate field, whereby further elongated plate parts (33-35) are punched out, said further plate parts being fastened with similar laps and similarily to the third and fifth plate field respectively, as the laps (2f) in the second plate field are fastened to the first and third plate fields respectively, whereby additional diagonal bars (33-35) are formed between the third plate field and the fifth plate field. 3. Method according to claim 1 or 2, characterized in that the fed plate, after having passed the circular path (24), is folded into a substantially V-form (C-C, D-D, fig.4), with the first and second plate fields (2a,2b) in one arm, with the third plate field (2c) substantially in the apex of the V-form and the fourth and fifth plate fields (2d,2e) in the other arm. 4. Method according to claims 1-3, characterized in that said two arms are further folded to a substantially I-form (E-E, fig.4), whereby a crossbar beam (A, fig.l) is formed with diagonal bars, the diagonal bars having a first orientation comprising the bent elongated plate parts ( 30- 32 ) of the second plate field (2b) and the diagonal bars having another orientation comprising the bent elongated further plate parts (33-35) of the fourth plate field ( 2d), with an upper frame made by folding together the first plate field ( 2a,4c) with the fifth plate field ( 2e, 4b ) into a T- profile, and with a lower frame made by bending the third plate field (2c,4a) into a T-profile. 5. Method according to claims 1-3, characterized in that the end areas -of the arms in the V-form, i.e. the first ( 2a,6b,6f ) , the third (2c,6a,6g) and the fifth ( 2e,6c,6h ) plate fields are bent into an U-form such that a trapezoidal cross section will be created, that the fed plate is cut and that a plurality of cut plate units are assembled into a supporting, trapezoidal crossbar construction (W, fig.7). 6. Method according to claim 1, characterized in that the first (9a, fig.9) and third (9b) plate fields are turned substantially 90° (fig.10) before feeding to the circular path (62, fig.8), and that the further work is made such, that it also comprises turning 180° a first length part (fig.13) of the machined plate length outputted from the circular path and comprising applying and fastening said first length part on a susequent substantially equally long second length part, in order to provide a crossbar beam (B, fig.15) where the diagonal bars (71,72) of the first length part have a first inclination and the diagonal bars of the second length part have a second inclination. 7. Method according to clams 1 and 6, characterized in that the crossbar beam is produced in an automatic production line (fig.8) comprising a plate reel (la), a punching and bending station (lb), a first roll-forming station (61), a circular path (62), a second roll-forming station (63), a turning station (64), a further roll-forming station (65) and a finishing station (66). 8. Method according to claims 1, 6 and 7, characterized in that the inclination of the diagonal bars in the crossbar beam are determined by the angle " (60°, fig.11) between the direction of the feeding path before and af er the circular path. 9. Crossbar construction made according to any of the claims 1-8, comprising an upper and a lower frame having intermediate diagonal bars, whereby each bar is fastened to the upper and lower frame, each with a jointless lap (2f,9k) respectively, characterized in that both laps have a twisted shape, which shape has been formed during the manufacturing process of the crossbar construction when a bar (30- 35,71,72), which has been punched out from a longitudinal plate, but which bar in both of its ends .is fastened to an adjacent plate field with said two laps and which bar has been bent into a substantially C-formed or similar profile, is fed further in a path (24,62) forming a circular arc, and that at least parts of the upper and lower frames consists of said adjacent plate fields.

Inventors: STEFFENSEN TAGE, STEFFENSEN, TAGE
Applicants: STEFFENSEN TAGE, STEFFENSEN, TAGE
Application year: 1992
Main classification: E04C3
IPC codes: B21D47, E04C3