Abstract:
A composite profile comprising an extruded aluminum alloy carrier profile comprising a rail head having a longitudinal axis B, the rail head comprises a surface and two longitudinal edges extending parallel to the longitudinal axis B and a metal channel shaped profile strip comprising a base portion spanning the surface of the rail head and parallel side legs which lie on the longitudinal edges of the head rail, an insert rod is provided on the parallel side legs which lie on the longitudinal edges of the head rail and engage in lateral slots provided in the two longitudinal edges of the rail head, wherein the profile strip is attached to the carrier profile under mechanical pretension by way of a weld seam which contacts the rail head of the extruded aluminum alloy carrier profile.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is related to U.S. application Ser. No. 11/708,210 filed Feb. 20, 2007 and U.S. application Ser. No. 11/815,018 filed Jul. 30, 2007. 
     BACKGROUND OF THE INVENTION 
     The invention concerns a composite profile having a rail-like carrier profile extruded from light metal material as well as a profile strip made of a harder metal and resting on its top surface. The invention covers a method for manufacturing such a composite profile. 
     DE 24 32 541 A1 shows a method for manufacturing conductor rails from a carrier profile and at least one overlay which forms at least part of the surface of the carrier profile serving as the conductor and which consists of a profile strip of a different metal to the covering profile having high abrasion resistance. The free cross-sectional ends of the flat profile strip are formed by edge surfaces which are inclined towards each other and which in the fitted position fit snugly against correspondingly inclined edge strips of a depression in the carrier profile which receives the profile strip. During an extrusion operation the carrier profile is produced by forcing a block out through the shaping cross-section of an extrusion die, and at the same time the profile strip passes through the die opening or shaping cross-section parallel to the longitudinal axis of the die. During the extrusion operation an intimate metallic bond is formed between the two profile components. For instance, when the conductor rail is used to electrify rail-mounted vehicles, in cases of particularly high load the profile strip comes away from its light metal carrier profile in the long term in spite of the intimate metallic bond. 
     DE 198 40 720 A1, which describes a steel strip with flat bottom and steel strip arms integrally formed thereon at right angles, refers to the document described above. These arms are provided with recesses for receiving rivets, bolts, screws or caulked joints. Those steel strip arms are inserted in slots at right angles to the steel strip bottom or to the top surface of the carrier profile, and then fixed with the rivets or the like to the inner wall of the slot. 
     In DE 44 10 688 A1 can be found a composite profile having a carrier profile made of light metal and a profile strip connected thereto. The latter spans the surface of a rail head of the carrier profile, is shaped like a channel in cross-section and comprises in its side arms, projecting at a distance from each other from its inner surface on the side of the supporting body, shaped portions which are embedded in the supporting body. These shaped portions define undercut gaps which are filled by the metallic material of the supporting body in form-fit relationship. This form-fit connection is not subject to the faults described for the metallic bond. 
     A composite conductor rail element for supplying power to a rail vehicle with a coating made of a material of high mechanical strength which is rigidly fixed to a rod made of material which is a good conductor of electricity and which forms the sliding or contact surface for current collectors of the vehicle, is disclosed by DE 25 46 026 A1. The coating is fixed to the conductive rod which serves as the carrier by wedging or squeezing the edges of the coating into the conductive rod. In the coating is formed at least one indentation which runs in the longitudinal direction and which penetrates as far as the conductive rod. For wedging the edges of the coating, in the conductive rod is provided a groove which is divided by a lip. The latter leads to wedging of the coating on the conductive rod as soon as it has been at least partially wrapped round and pressed against the edge of the coating. 
     Conductor rails of which the wear components are attached to the live carrier profile by screws or additional inserts passing through them laterally, also proved to be disadvantageous. Other known manufacturing methods can disadvantageously lead to undulations on the surface of the covering profile, caused by caulking or stamping the carrier profile in stages. 
     Knowing this state of the art, the inventor set himself the aim of more extensively improving the connection between carrier profile and profile strip, while retaining the special capacity for economical manufacture. 
     SUMMARY OF THE INVENTION 
     The object is achieved by a composite profile having a rail-like carrier profile extruded from light metal material as well as a profile strip made of a harder metal and resting on its top surface, of which the cross-section has associated with it at either end a recess in the carrier profile, the carrier profile and profile strip being joined together in force-fit and/or form-fit relationship, characterised in that joined to the profile strip or covering profile which rests on the top or upper surface of the carrier profile at each of its longitudinal sides is an insert rod which is parallel to its longitudinal axis (B) and formed from the material of the profile strip or covering profile and which on the other hand engages in a lateral slot in the carrier profile and is connected to the profile strip by a weld seam, the channel-like profile strip being fixed by its anchor or insert rod to the carrier profile under mechanical prestressing. 
     According to the invention, joined to the profile strip or covering profile which rests on the top or upper surface of the carrier profile—preferably made of special steel—at each of its longitudinal sides is an insert rod which is parallel to its longitudinal axis and formed from the material of the profile strip or covering profile and which on the other hand engages in a lateral slot in the carrier profile and is connected to the profile strip by a weld seam; the channel-like profile strip is fixed by its anchor or insert rod to the carrier profile under mechanical prestressing. 
     According to a further characteristic of the invention, a channel-like insert rod of approximately V-shaped cross-section is used, which with the longitudinal edge of an outer channel arm is associated with the end face of a side arm of the profile strip and rigidly connected by the weld seam. In this case the other channel arm which is directed towards the longitudinal axis of the profile strip is to form with the outer channel arm an apex angle of less than 90° and be mounted in a slot inclined at a corresponding angle to the cross-sectional longitudinal axis of the carrier profile; this apex angle of the channel cross-section measures about 60° to 70°, preferably 65°. 
     Advantageously, the longitudinal edge of the outer channel arm runs at a short axial parallel distance from the free end of the other channel arm, i.e. the two arm ends almost define a common plane. 
     It is of particular importance that in the fitted position the end face of the side arm of the profile strip is to be approximately aligned with the longitudinal edge of the outer channel arm. The channel arm therefore does not abut against the inner surface of that profile strip apex, or abuts against it only slightly. Also a V-shaped cross-section of the slot is to be provided in the rail head of the carrier profile; one of the slot arms is a longitudinal recess in the lateral or longitudinal surface of the rail head, which ends at a radial cross-sectional step aligned with the end face of the side arm of the profile strip. 
     It is within the scope of the invention that the weld seam has an approximately triangular cross-section with two sides at right angles to each other, of which one is formed integrally with the end face of the profile strip and of which the other side is formed integrally with the outer surface of the associated channel arm of the insert rod. In a preferred embodiment the two sides of the approximately isosceles cross-section of the weld seam are connected by a hypotenuse as a sloping surface. 
     It proved to be favourable to let the weld seam with its sloping surface attach to the outer edge of the end face of the profile strip; the cross-sectional width of the weld seam here corresponds roughly to the thickness of the insert rod. 
     In another application the weld seam attaches to the end face of the profile strip at a distance from its outer edge, and the cross-sectional width of the weld seam is smaller than the thickness of the insert rod. 
     Of particular importance is a counter-bead of the weld seam which is made of its material which during the welding operation passes through between the adjoining regions of profile strip and insert rod at their inner surface and is bonded thereto. The weld seam and counter-bead run parallel to each other and in the fitted position form a unit. 
     In this connection it should be pointed out that the insert rods formed from steel are modified in such a way that lateral welding penetrates through to the light metal of the carrier profile. Due to welding through to the aluminium, the following advantages amongst others arise:
         the contact resistance is uniformly good over the whole length, that is, regardless of tolerances;   current can be collected uniformly over the whole steel surface;   the possibility of the steel or profile strip  40  sliding on the carrier profile due to thermal stresses is excluded.       

     The invention also covers a method for manufacturing a composite profile of the embodiment described above, in which a carrier profile having a top surface and insertion slots accompanying the latter on both sides is extruded from light metal material, also in each insertion slot an insert rod is introduced, and a profile strip covering the top surface is applied to a section of the insert rod protruding from the insertion slot in such a way that the covering profile is subject to prestressing relative to the carrier profile. 
     The insert rod is rolled or pressed tight against the carrier profile with prestressing and welded to this profile strip throughout. Here it proved to be particularly advantageous to make a counter-bead connected parallel to the weld seam from its material in such a way that the latter is fixed to adjacent inner surfaces of the carrier profile and insert rod. 
     First, therefore, the anchoring strips, anchor rods or insert rods are laid or pressed or rolled into the light metal profile, in particular a basic aluminium profile, or rolled or pressed tight before welding or subsequently by permanent deformation of the carrier profile. Care must be taken here that the prestressing is built up between the partners. There is then provision for pressing the special steel covering profile onto the light metal carrier profile by means of a contact pressure roller of large diameter, and, under this prestressing, welding the anchoring strips or insert rods to the covering profile on the left and right simultaneously. 
     Moreover the so-called covering profile is preferably a special steel strip cut from a rolled coil, which by roll forming is given the desired shape or used directly as a cut strip. The insert rod is a special steel strip—preferably the same alloy as the covering profile—which has been advantageously cut from the rolled coil and given the desired shape by roll forming/bevelling/turning edges up or over. 
     To eliminate the above-mentioned faults, a continuously unwinding composite profile—like extrusion for the carrier profile and roll forming—over the whole profile length of covering profile and insert rods or anchoring profiles is proposed. The connection is made by continuous welding over the profile length. 
     The requirement is a maximum possible width of the sliding surface with the possibility of spreading from the side and mechanical anchoring which, even with completely worn wear profiles, ensures anchoring of the remaining sliding surfaces of which there are then two. Also, a reduction of the fitted height tolerances compared with known composite profiles is desired. The possibility of local manufacture worldwide is desirable too, without having to upgrade a large light metal extruder. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages, characteristics and details of the invention are apparent from the description below of preferred embodiments and with reference to the drawings, which show 
         FIG. 1 : an oblique view of a section of a rail-like composite profile consisting of two composite partners in the form of a rail profile with covering profile and two components connecting them in the form of channel-like insert rods; 
         FIG. 2 : the enlarged end view of the composite profile of  FIG. 1 , from which an insert rod is taken out on its right profile side; 
         FIG. 3 : the insert rod taken out in  FIG. 2  in an end view; 
         FIG. 4 : the end view of the covering profile used as a composite partner in  FIG. 1 ; 
         FIG. 5 : an enlarged detail from  FIG. 2  with the insert rod in the connecting position not shown there; 
         FIG. 6 : a representation, corresponding to  FIG. 5 , of another embodiment of the detail shown in  FIG. 5 ; 
         FIG. 7 : an end view of another embodiment of the composite profile roughly corresponding to  FIG. 2  and on a larger scale than the latter; 
         FIGS. 8 to 10 : drawings of manufacturing steps for the conductor rail; 
         FIG. 11 : a drawing of a production frame for the conductor rail; 
         FIG. 12 : an enlarged detail of the conductor rail in the production frame in the end view of  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION 
     A composite profile  10  with a height h of 105 mm here and a maximum width b of 92 mm according to  FIG. 1  comprises a rail-like carrier profile  12  having a rail foot  14  and a continuous rail head  22  formed integrally on the latter by means of a rail web  20 . Two longitudinal edges  17  with a height c of 10 mm defining the foot surface  16  of the rail foot  14  run parallel to each other at a distance b 1  of 80 mm here. 
     From these longitudinal edges  17 , the two ridge surfaces  18  of the rail foot  14 , which are somewhat inclined towards them, are inclined slightly upwards to the cross-sectional centre axis Q crossing the longitudinal axis A of the composite profile  10 , and merge with that axial rail web  20  with a height h 1  of approximately 30 mm and a thickness e of approximately 18 mm. Adjoining the upper end of the rail web  20  are the lower surface  26  which extends to the longitudinal edges  24  of the rail head  22  and of which the width b 2  measures approximately 78 mm and of which the outside height n of approximately 28 mm defines the position of the rail head surface  28 . 
     From each of the longitudinal edges  24  of the rail head  22  in  FIGS. 1 ,  2  extends an insertion slot  30  which is inclined upwards at an angle w of approximately 60° to the cross-sectional longitudinal axis Q and which has a width a of 3 mm here and a depth t of 18 mm and of which the lower wall surface in  FIG. 2  merges with a kind of longitudinal rib  34  of the rail head  22 ; the outer side of the longitudinal rib  34  is formed by that lower surface  26 . In the longitudinal edge  24  is made a longitudinal recess  32 , forming a cross-sectional step  33 , as a three-dimensional extension of the cross-sectionally V-shaped slot  30  which also provides its width a. 
     This rail or carrier profile  12  of the composite profile  10  is formed from a light metal material, in particular an aluminium alloy, in an extruder not shown in the drawings for reasons of clarity. 
     The flat top or upper surface  28  of the rail profile  12  or its rail head  22  is in the final state spanned by a profile strip  40  with a thickness f of 6 mm which is made from a ferrous or non-ferrous heavy metal. This profile strip  40  is cross-sectionally channel-shaped, and its side arms  46  with a height c 1  of 18 mm, which extend from a base plate  42  and are parallel to each other and to the longitudinal axis B of the profile strip  40 , abut against the longitudinal edges  24  of the rail head  22 . In this position the flat outer surface  44  of width q of the profile strip  40  forms the surface of the composite profile  10 . 
     Associated with parallel axis with each side arm  46  of the profile strip  40  resting on the surface  28  of the rail head  22  is, on the inside, a channel-like insert rod  50  with an approximately V-shaped cross-section of an apex angle w 1  of approximately 60°, of which the cross-sectionally linear channel arms  49 ,  49   i  provide a thickness a 1  which with slight play corresponds to the width a of the insertion slot  30  and here measures 2.8 mm, for example. The right channel arm  49  in  FIG. 3  of the insert rod  30 , which is also referred to as an anchor rod, is aligned in the fitted position with its outer surface—running parallel to the cross-sectional longitudinal axis Q—with the inner surface of the side arm  46  of the profile strip  40 . The distance c 2  from the end edge  47  of the profile strip side arm  46 —and hence also the longitudinal edge  48  of a channel arm  49  of the insert rod or profile  50 , to the inner lower surface  45  of the profile strip  40  is 11.9 mm here; the longitudinal edge  48  of the channel arm  49  which according to  FIG. 3  runs at only a short axial parallel distance i from the free end of the other channel arm  49   i  is aligned in the fitted position approximately with the end face  47  of the profile strip side arm  46 . 
     The end face  47  of the profile side arm  46  is sealingly welded to that longitudinal edge  48  of the channel arm  49  by a weld seam shown at  52 . The latter runs on that end face  47  of the profile strip side arm  46  and on the outer surface of the outer channel arm  49  in such a way that its outer surface  51 —forming a sloping surface—is inclined at an angle y of approximately 40° cross-sectionally to the insert rod  50 . Preferred is a cross-section of the weld seam  52  after the fashion of a right-angled and isosceles triangle of which the two arms defining the right angle are therefore of approximately the same length; the sloping surface  51  is then a hypotenuse. 
     Each side arm  46  of the profile strip  40  forms a fixed unit, owing to the position of the weld seam  52  described, with the latter and the insert rod  50 . In  FIG. 5  the weld seam  52  and its sloping surface  51  extend from the outer edge of the end face  47 . Here the cross-sectional width z of the weld seam  52  measures approximately 3 mm, and so corresponds approximately to the thickness a 1  of the wall of the insert rod  50 . In  FIG. 6  the cross-sectional width z of the weld seam  52   e  is smaller, because here the sloping surface  51  attaches to the end face  47  at a distance from its outer edge  43 . A maximum of 1/10 mm to 2/10 mm is left free at the end face  47  so that the welding material can take up the aluminium. The other channel arm  49   i  is inserted in the adjacent slot  30  of the rail head  22 . The angle γ here measures approximately 45°. 
     In  FIG. 6  is shown as a further embodiment at  54  a counter-bead of the weld seam  52   e  which is formed continuously on the inside of the closed gap between the side arm  46  and the insert profile  50  owing to a through-gap existing between the two parts  46 ,  50 . This counter-bead  54  can be formed both on this weld seam  52   e  and on the weld seam  52  of  FIG. 5 . 
     A permanent and tight bond of the two composite partners  12 ,  40  of the composite profile  10  which is under mechanical prestressing is formed. This prestressing between the composite partners determines their capacity for use; for this prestressing is vital for the contact resistances, the corrosion behaviour and hence for the life of current transmission. 
     In  FIG. 7  can be seen the head region of the carrier profile  12 , on a larger scale than  FIG. 2 , with a top casing  60  which spans its top surface  28 —as stated, preferably made of steel—and of which the cross-section is formed from the covering profile  40 , the two insert rods  50  and the weld seams  52  connecting the latter into a unit. With the arrows at D, uniform delivery of current from the topic casing  60  to the rail head  22  is symbolised. 
     By way of examples, cross-sectional values of the materials used, aluminium (number I) and steel (number II), are compiled below: 
     
       
         
               
               
             
               
               
               
               
               
               
             
           
               
                   
               
               
                 I 
                 II 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Cross-sectional area: 
                 4517.28 
                 mm 2   
                 Cross-sectional area: 
                 778.34 
                 mm 2   
               
               
                 Density: 
                 2.7 
                 kg/dm 3   
                 Density: 
                 7.8 
                 kg/dm 3   
               
               
                 Weight per linear meter: 
                 12,197 
                 kg/m 
                 Weight per linear meter: 
                 6,071 
                 kg/m 
               
               
                 Centre-of-gravity system 
                   
                   
                 Centre-of-gravity system 
               
               
                 Moment of inertia I x : 
                 164.61 
                 cm 4   
                 Moment of inertia I x : 
                 72.49 
                 cm 4   
               
               
                 Moment of inertia I y : 
                 527.13 
                 cm 4   
                 Moment of inertia I y : 
                 4.66 
                 cm 4   
               
               
                 Moment of deviation I xy : 
                 0 
                 cm 4   
                 Moment of deviation I xy : 
                 0 
                 cm 4   
               
               
                 Principal item system 
                   
                   
                 Principal item system 
               
               
                 Principal moment of inertia I 1 : 
                 164.61 
                 cm 4   
                 Principal moment of inertia I 1 : 
                 4.66 
                 cm 4   
               
               
                 Principal moment of inertia I 2 : 
                 527.13 
                 cm 4   
                 Principal moment of inertia I 2 : 
                 72.49 
                 cm 4   
               
               
                 Length outer contour: 
                 485.34 
                 mm 
                 Length outer contour: 
                 328.31 
                 mm 
               
               
                 Length inner contour: 
                 0 
                 mm 
                 Length inner contour: 
                 0 
                 mm 
               
               
                   
               
             
          
         
       
     
       FIGS. 8 to 12  illustrate the manufacturing method according to the invention. First the two insert rods  50  made of special steel are delivered to the extruded rail profile  12  as in  FIG. 8  and their inner channel arms  49   i  are inserted in the respective insertion slots  30 . Then all the special steel profiles, that is, the insert rods  50  and the covering profile  40 , are pressed on, the latter against the top surface  28  of the rail or carrier profile  12  ( FIG. 9 ). Then these parts are welded under pressure P; welding jets used are marked  70 . 
     As already mentioned, the insert rods  50  formed from steel are modified in such a way that lateral welding through to the aluminium of the carrier profile  12  takes place. Welding through to the aluminium leads above all to the contact resistance being uniformly good over the whole length—that is, regardless of tolerances—and current collection can take place uniformly over the whole steel surface. Also the possibility of the steel or profile strip  40  sliding on the carrier profile  12  due to thermal stresses is excluded. 
     Resting on a lower contact pressure roller  72   t  in  FIG. 11  is the unit consisting of covering profile  40  and rail profile  12  with which—not visibly—the two insert rods  50  are associated. An upper contact pressure roller  72  is associated with the foot surface  16  of the rail foot  14 . These special rollers  72 ,  72   t  which are mounted on parallel shafts  74  and adapted exert the necessary vertical pressure, while lateral pressure plates  80  which are rotatable on bearing arms  76  of a ridge frame  78  inclined on axles  79  of holding plates  77  exert pressure on the insert rods  50 . This is a modified roller straightening machine for light metal profiles. In order to achieve optimum prestressing here, welding is carried out between the contact pressure rollers  72 ,  72   t  made of non-magnetic material—and in fact the two sides are worked simultaneously. 
       FIG. 12  shows an essential detail of the conductor rail  10  according to the invention which provides the required prestressing. A corner region of the rail head  22  with insertion slot  30  can be seen and, lying stationarily in the latter, an insert rod  50  which on the other side is joined to the side arm  46  of the profile strip or covering profile  40  and is pressed during the welding operation by those pressure plates  80 , which are held at an angle of inclination w 2  of approximately 35°.