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BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The innovation relates to a floor strip for bridging a join between two floor coverings that border on one another. 
   2. The Prior Art 
   A floor profile arrangement is shown in German Patent No. DE 201 17 167 U1, in which a base profile having two upright shanks accommodates a cover profile that engages over the two upright shanks with two crosspieces, so as to be adjustable in height. In order to bridge greater heights, the crosspieces are configured to be somewhat longer on the underside of the cover profile. In order to equalize excess lengths when pushing the floor profile and the cover profile together, depressions or perforations are provided in the side arms of the floor profile, which accommodate the excess lengths. Pivoting of the cover profile in the case of floor coverings having different thickness is not possible. 
   Another floor profile arrangement is shown in German Patent No. DE 203 20 273 U1, in which an articulation is provided on a base profile. An upright connecting part having a drive channel is held in the articulation in an articulated manner. A cover profile engages over the connecting part with two crosspieces molded onto its underside. The crosspieces form the guide, and the cover profile is fixed in place in the drive channel with screws that engage from above. In order to be able to pivot the cover profile even when the crosspieces have been pushed far over the floor profile, lateral recesses have been provided in the floor shank(s) of the floor profile, and, at the same time, the crosspieces have been shortened at the other locations, so that they offer the side guide only in partial regions. The crosspieces that are dually set onto the cover profile require broad joins between the adjacent floor coverings, particularly if two coverings having different thickness border on one another, and the cover profile has to be greatly inclined. Because of the low point of rotation and the crosspieces that stand far apart from one another, the cover profile is greatly displaced laterally when it is pivoted, and in many instances, the floor covering is not grasped sufficiently, so that the base profile has to be loosened and re-attached to the floor after it has been moved. 
   SUMMARY OF THE INVENTION 
   It is therefore an object of the invention to equalize great height differences in floor coverings having a different thickness, with a cover profile held in an articulated manner relative to the base profile, without any bump, and to hold the coverings together as tightly as possible. 
   This object is accomplished by a floor strip for bridging a join between two floor coverings that border on one another, comprising a base profile that can be fixed in place on the floor, two upwardly extending shanks molded on the base profile, and a cover profile having at least one cover wing that projects laterally. There is a downwardly directed crosspiece, which is connected with the base profile by way of an articulation. The articulation is formed by an articulation rail that is rounded on both sides and grasped between the shanks of the base profile. The shanks are upright but rounded on the inside. The articulation rail is formed by a solid material or by a sleeve, which has a longitudinal groove, into which the crosspiece and/or an attachment means that engages through the cover profile passes. In certain sections, the longitudinal groove passes completely through the articulation rail to form perforations, and the crosspiece of the cover profile has a greater depth in these regions. 
   Via the groove in the articulation rail, which passes all the way through, the crosspiece of the cover profile can be introduced further, specifically directly through the center of the articulation. As a result, the cover profile comes to rest lower on the floor covering, because the crosspiece does not get stuck in the articulation rail, but rather passes through all the way to the floor profile. During pivoting, the crosspiece that passes through the center of the articulation rail has the advantage that the join region between the adjacent coverings can be made narrow. Because of passing centrally through the articulation rail, the cover profile is hardly displaced laterally at all during pivoting, so that the floor coverings are sufficiently grasped in every slanted position, and the join is covered. 
   Even greater equalization of the height difference can be achieved if the base profile is provided with recesses that pass through it, under the section-wise perforations of the articulation rail. The depth region for inserting the crosspiece of the cover profile is increased even further with the recesses in the base profile below the continuous groove through the articulation rail. If one was previously able to utilize ¾ of the region of the diameter of the articulation rail as a holding or guiding part for the crosspiece to be inserted, and therefore several cover profiles having crosspieces of different lengths were required for floor coverings having different thickness, it has now become possible to equalize significantly greater difference ranges with one crosspiece length, and in particular, to do so by passing right through the center of the articulation all the way to the floor on which the base profile is fixed in place. The crosspiece cannot be inserted any deeper than that, unless one were to chisel out the floor underneath at these locations. 
   In order to sufficiently pivot the cover profile in any desired position, so that the floor covering is sufficiently grasped, even if the floor coverings have only a low height and the crosspiece must penetrate deep through the groove, it is advantageous to configure the recesses in the base profile to be so wide that the crosspiece of the cover profile that engages through the articulation rail has a pivoting freedom of 20°. It has been shown that pivoting freedom of 10° toward each side is sufficient for grasping the coverings. Since the articulation rail with its groove is situated directly above the recess of the base profile, the cutout for a pivot of 20° is only slight, so that the base profile is not weakened by this recess. As experiments have shown, it is possible to place even larger cutouts, because they are always provided only in certain sections. Sufficient rigidity remains for the base rail, even if it consists of plastic and not of metal, because it is fixed in place on the floor by means of being glued or screwed down. 
   In order to equalize the greatest possible height difference with the cover rail, it is practical to make its crosspiece quite long. The correct length for the crosspiece is obtained when the crosspiece of the cover profile has a depth directed downward, in the section region of the recesses that pass through, that reaches all the way to the floor in the lowermost position of the cover profile, so that it sits on the upwardly standing shanks of the base profile. This length can easily be measured, and it guarantees that the crosspiece touches the direct floor in its lowest position, and is not held back by the base profile. 
   Because the recesses in the articulation rail and the base profile are provided only in certain sections, and therefore have specific lengths, the extended crosspieces must be adapted to these lengths. For safety reasons, it is advantageous if the extended crosspiece of the cover profile that engages through the recess is configured to be shorter in the longitudinal rail direction than each of the lengths of the perforations and recesses provided in certain sections, through the articulation rail and the base profile. The cover profile may shift slightly, in the longitudinal direction, relative to the base profile and/or the articulation rail. Even then, the crosspiece should be able to engage through the recesses, in order to lock the cover profile in place quite low above the floor and grasp the covering. 
   In order for the cover profile to find sufficient hold in the articulation rail despite its shifting seat, the crosspiece of the cover profile engages through the groove passing through the articulation rail with a slide fit. The cover profile can be pulled out of the articulation rail relatively far, because of the greater depths of the crosspieces, and the crosspiece ends still have sufficient hold in the slide rail because of the seat for slide fit, and do not bend or actually fold over. The crosspieces with the greater depths are only provided in certain sections. 
   It is advantageous if the articulation rail, when it is configured as a sleeve, has edge ends directed upward on its upper longitudinal groove. An acute-angle toothed rib directed inward, in each instance, is molded on these edge ends as an end piece. The beaded edge on the groove of the sleeve-like articulation rail possesses an extension for holding the crosspiece of the cover profile, because in this way, additional side walls are created, which can rest against the crosspiece on both sides. The toothed rib that is molded on as an end piece holds the inserted crosspiece tightly in place even if it engages between the edge ends only with a slight length. The toothed ribs engage the crosspiece with a firm hold from both sides, at the required height. This can be from the outer end to below the laterally projecting cover wings of the cover profile. Therefore great height equalization is possible with one part. 
   In order for the seat and the hold of the cover profile to be even better and firmer if the crosspiece is pushed somewhat further into the articulation rail, the articulation rail has an additional toothed rib directed at an inward and downward slant inward on the edge ends, which stand upright, below the end piece. With the second toothed rib that is directed at a slant inward and downward, the crosspiece is grasped twice and therefore has no possibility of coming loose. 
   It is advantageous if the slanted outer edge ends of the longitudinal groove of the articulation rail serve as a stop at the ends of the shanks of the base profile. The cover profile orients itself, in terms of its slanted position, essentially by supporting its wing edges on the floor covering. As long as the edges have not yet reached the floor covering, it is advantageous if the cover profile does not angle off too greatly, in order to remain in the pivot range when it is set down. Practice has also shown that pivoting of 20° is sufficient for adaptation to the floor coverings having different thickness. 
   In order for the cover profile to be able to hold itself in the articulation rail with its crosspiece, the crosspiece of the cover profile and the insides of the longitudinal groove in the solid material of the articulation rail are equipped with a surface structure that engage into one another. The surface structure can be a fine graining with which a hold is possible with almost step-free displacement. However, reciprocal furrowing or tooth-provision is also possible, in order to achieve an advantageous hold for the cover profile, which can also be adjusted if it has become loose over time and fixation in place only occurs by way of the surface structure. Since the sleeve-like articulation rail is already equipped with toothed ribs, these have a firm grip on the crosspiece of the cover profile if the crosspiece has a marked surface structure. 
   Finally, the firm seat for the cover profile is increased in every height position if the surface structure extends on both sides over the entire surface of the crosspiece. An attempt is made, with the innovation, to cover a greater height difference of floor coverings, without using additional parts or actually replacement parts. Consequently, it is advantageous if the crosspiece of the cover profile is as long as possible, thereby can be pulled far out of the groove of the articulation rail, and nevertheless finds sufficient hold in the articulation rail that it also holds the floor covering. On the other hand, it should be possible to push the crosspiece quite deeply through the articulation rail, all the way to the floor, in order to grasp coverings having a thin wall, and to still find sufficient hold in the articulation rail groove even then. This can be achieved if the surface structure extends on both sides over the entire surface of the crosspiece. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention. 
     In the drawings, wherein similar reference characters denote similar elements throughout the several views: 
       FIG. 1  shows a floor strip that can pivot, pulled apart; 
       FIG. 2  shows another floor strip, joined together; 
       FIG. 3  shows the floor strip, joined together, in a low arrangement; 
       FIG. 4  shows an articulation rail in sleeve form; 
       FIG. 5  shows a floor strip cut open from the side, broken down in an exploded view; 
       FIG. 6  shows another floor strip, and 
       FIG. 7  shows the previous floor strip, pulled apart in an exploded view and cut open from the side. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   As can be seen in  FIG. 1 , floor strip  1  consists of a base profile  2 , which has a lateral flange  3 , with which it is fixed in place on the floor. Furthermore, two shanks  4  that are molded on and are directed upward proceed from base profile  2 , which shanks are rounded on the inside and serve as articulation bearings  5 . In articulation bearing  5 , an articulation rail  7  is held by rounded inside surfaces  6  of shanks  4 , so as to rotate. Articulation rail  7  is laterally adapted to the rounded regions of inside surface  6  of shanks  4 , and has a groove  8  that is open toward the top, into which a crosspiece  9  of a cover profile  10  engages, which is molded onto the underside of cover profile  10 . Cover profile  10  has two lateral wings  11 , one of which could be angled away if cover profile  10  is used as an edge delimitation. With the two edges  12 , cover profile  10  grasps the floor coverings, not shown, which form a join at the abutment point, which join is bridged by cover profile  10 . Crosspiece  9  engages into the groove  8  of articulation rail  7 , in order to hold itself or at least to give cover profile  10  a good guide in the vertical direction, when the profile is pressed onto the floor covering. 
   In order to make it possible for cover profile  10  to be pressed more deeply onto base profile  2 , and for crosspiece  9  not to sit on the bottom of groove  8  in articulation rail  7 , articulation rail  7  is configured so that groove  8  passes completely through it, in certain sections. The sections that are completely open or cut out are indicated with  13 . Crosspiece  9  has extended depths  14  at these perforations  13 , which are present in certain sections, which depths are configured to be slightly shorter than section-wise perforations  13 , in the longitudinal direction of floor strip  1 . In this way, it is guaranteed that extended depths  14  will pass through perforations  13  even if they are slightly displaced in the longitudinal direction. Because of the greater depth  14 , crosspieces  9  can be drawn further out of groove  8  and hold thicker floor coverings. Crosspieces  9  nevertheless still find sufficient hold in groove  8 . 
   In order to be able to equalize an even greater height difference, an even greater depth  14  was given to crosspiece  9  in certain sections. For this purpose, base profile  2  was also provided with corresponding cutouts  16 , on bottom flange  15 , below articulation rail  7 , specifically directly below section-wise perforations  13 . These cutouts  16  in base profile  2  can be seen in  FIG. 2 . 
   In  FIG. 2 , the crosspiece  9  of cover profile  10  is inserted in the uppermost position, and is held by the last elevation of furrows  17  of groove  8 . Since groove  8  of articulation rail  7  is configured as a drive channel having a furrowed or ribbed surface structure  18 , a screw, not shown, that passes through cover profile  10  could be provided in addition to crosspiece  9 . Crosspiece  9  would have a recess at this point, so that the screw finds sufficient grip in the drive channel. It is important that crosspiece  9  engages centrally through the articulation rail  7  and articulation bearing  5 , and furthermore through base profile  2 , in order to make the deepest possible depth with crosspiece  9 , and remain in the tightest space. 
   In  FIG. 3 , the same floor strip  1  as in  FIG. 2  can be seen, but here cover profile  10  is completely pressed down, so that crosspiece  9 , with its extended length  14 , engages entirely through articulation rail  7  and through cutout  16  of base profile  2 , all the way to floor  19 . In this position, cover profile  10  sits on top of shanks  4  of base profile  2 , which project upward, or on top of top groove edges  20  of articulation rail  7 , if these project out of articulation bearing  5 . Crosspiece  9  is configured to be so wide that it sits in the groove with a slide fit, with its smooth wall, and can be displaced without resistance. With this configuration, cover profile  10  gets its hold in groove  8 , i.e. in the drive channel, from a screw that passes through. Cutout  16  is cut out so wide, in base profile  2 , that crosspiece  9 , which passes through articulation rail  7 , can pivot freely by at least 20° with its extended depth  14 , and thereby brings cover profile  10  into the desired slanted position so that it is set down on the floor coverings on both sides with edges  12  of wings  11 , and is able to hold them. Cover profile  10  is reinforced with a reinforcement rib  29  on each wing  11 , on its underside. This reinforcement rib  29  offers cover profile  10  greater rigidity, even if the wall thickness of wing  11  is only 1.5 mm. 
   In  FIG. 4 , floor strip  1  is pulled apart, in an exploded view, and additionally cut longitudinally. As a result, it is very easy to see recesses  16  in base profile  2 , which are cut out of floor flange  15  in certain sections. Furthermore, one can see the rounded inside surface  6  of articulation bearing  5 , which is part of the one shank  4 , in which articulation rail  7 , shown above it, is mounted. Groove  8  provided in articulation rail  7  has a surface structure  18  of furrows that run longitudinally, in connection with which crosspiece  9  of cover profile  10  slides by when it is inserted into the groove  8 . Above recesses  16  of base profile  2 , passage perforations  13  of groove  8  are provided in articulation rail  7 , through which extended depths  14  engage, which are also provided in certain sections, like perforations  13  and recesses  16 . As can be seen, extended depths  14  extend over a shorter section in the longitudinal direction than perforations  13  and recesses  16  that are provided in certain sections, which are essentially disposed one on top of the other. Extended depths  14  are provided to be so long and at sufficient intervals that in the case of the uppermost position according to  FIG. 2 , cover profile  10 , with its crosspiece  9 , i.e. its depth  14 , still finds sufficient hold in the groove  8  of articulation rail  7 . 
   As is evident from  FIG. 5 , crosspiece  9  and its extended depth  14  of cover profile  10  are completely covered with a tooth pattern in the longitudinal direction as surface structure  18 . Articulation rail  7  is also configured accordingly; this will be discussed in greater detail in connection with the next figure. In  FIG. 5  shows depths  14  that have been molded onto crosspiece  9  in certain sections, and perforations  13  and cutout or recesses  16  that are provided in certain sections of articulation rail  7  disposed below, and base profile  2 , shown again below that. Perforations  13  and recesses  16  are provided so that crosspieces  9  can engage completely through the articulation, all the way to floor  19 , with their depths  14 , in order to thereby lose height if crosspiece  9  nevertheless has a great depth. Depths  14  have a shorter length  20 , in the longitudinal direction of the strip, than perforations  13  with their length  21  in articulation rail  7 , and recesses  16  with their length  22  in the base profile  2 , whereby lengths  21  and  22  are the same. 
   In  FIG. 6 , articulation rail  7  is shown as a sleeve, which is preferably produced from plastic having a Shore hardness of approximately 80 to 90. This sleeve shape has the required rounded surfaces  23  on the side, with which it is held in the articulation bearing  5 , by inside surfaces  6  of base profile shanks  4 , so as to rotate. Toward the top, sleeve-like articulation rail  7  is provided with a slot or a groove  8  for accommodating crosspiece  9  of cover profile  10 , edge ends  24  of which are drawn upward. Edge ends  24  have a toothed rib  25 , directed into groove  8  as the end piece, which assures sufficient fixation of crosspiece  9 . In order to further increase the attachment of crosspiece  9  in articulation rail  7 , another toothed rib  26 , directed inward, is molded on below toothed rib  25 , at a slight distance, like a saw tooth. Lower base  27  of sleeve-like articulation rail  7  is provided with perforations  13 , in certain sections, so that depths  14  of crosspiece  9  can pass through without resistance when penetrating deeper, and cover profile  10  loses height. 
   In  FIG. 7 , the assembly of a floor strip  1  having a sleeve-like articulation rail  7  can be seen. Base profile  2  is attached to the floor with its side flange  3 . Sleeve-like articulation rail  7  is mounted between upright shanks  4  of base profile  2 , so as to rotate, and the rail is held in inside surfaces  6  of articulation bearing  5  with its rounded side surfaces. In base profile  2 , section-wise cutout  16  in the floor flange  15  is configured to be wider for the pivot range of crosspiece  9 . Above cutout  16 , perforation  13  for passage of crosspiece  9  or its extended depth  14  is provided in sleeve-like articulation rail  7 . Cover profile  10 , with its crosspiece  9  formed on the underside, and with depth  14  that is extended in certain sections, is inserted into groove  8  of articulation rail  7 . Toothed rib  25  molded onto high-drawn edge end  24  engages into ribbed surface structure  18  of depth  14 , and already provides a firm hold. In this position, the greatest hold of cover profile  10  is assured. Cover profile  10  can be pressed down completely, until it sits on the floor coverings, not shown, with its edges  12  of cover wings  11 . With floor coverings having different heights, cover profile  10  will pivot with articulation rail  7 , until both edges  12  have contact with the floor covering. If the floor covering is very low, crosspiece  9  will penetrate very far into groove  8  of articulation rail  7 , and in the bottommost position, depths  14  pass through perforations  13  and cutouts  16  all the way to floor  19 , whereby then, the wings come to lie on the upper end  28  of shanks  4 . When edge ends  24  of articulation rail groove  8  look out of upright shanks  4  of the base profile, cover profile  10 , in its lowermost position, already sits on these edge ends  24 , and section-wise depths  14  touch floor  19 . In the angled position, the outermost edge end  24  of the longitudinal groove  8  of the articulation rail  7  lays itself against the upper end  18  of the shank  4  of the base profile  2 , and utilizes it as a stop. 
   The innovation is not restricted to the exemplary embodiments disclosed above. Instead, a plurality of variants, modifications, and combinations of individual details described in different embodiments is possible, which also make use of the idea of the invention, and therefore fall within the scope of protection. 
   LIST OF REFERENCE NUMERALS 
   
     
       
             
             
           
         
             
                 
             
           
           
             
               1 
               floor strip 
             
             
               2 
               base profile 
             
             
               3 
               side flange 
             
             
               4 
               shank 
             
             
               5 
               articulation bearing 
             
             
               6 
               inside surfaces 
             
             
               7 
               articulation rail 
             
             
               8 
               groove 
             
             
               9 
               crosspiece 
             
             
               10 
               cover profile 
             
             
               11 
               wing 
             
             
               12 
               edge 
             
             
               13 
               perforation 
             
             
               14 
               extended depth 
             
             
               15 
               floor flange 
             
             
               16 
               cutout, recess 
             
             
               17 
               furrows 
             
             
               18 
               surface structure 
             
             
               19 
               floor 
             
             
               20 
               length of the depth 14 
             
             
               21 
               length of the perforation 13 
             
             
               22 
               length of the recess 16 
             
             
               23 
               rounded surface 
             
             
               24 
               edge ends of the groove 
             
             
               25 
               toothed rib 
             
             
               26 
               toothed rib (saw tooth) 
             
             
               27 
               lower base of the articulation rail 
             
             
               28 
               shank end 
             
             
               29 
               reinforcement rib

Summary:
A floor strip for bridging a join between two floor coverings that border on one another comprises a base profile that can be fixed in place on the floor, two upwardly extending shanks molded on the base profile, and a cover profile having at least one cover wing that projects laterally. There is a downwardly directed crosspiece, which is connected with the base profile by way of an articulation. The articulation is formed by an articulation rail that is rounded on both sides and grasped between the shanks of the base profile. The shanks are upright but rounded on the inside. The articulation rail is formed by a solid material or by a sleeve, which has a longitudinal groove, into which the crosspiece and/or an attachment means that engages through the cover profile passes. In certain sections, the longitudinal groove passes completely through the articulation rail, and the crosspiece of the cover profile has a greater depth in these regions.