Abstract:
A link member for tire chains has a link member body having at least one connecting opening for receiving additional chain members. The link member body has a tire contact part and a wear part, wherein the wear part has lateral studs and at least one central stud. The lateral studs are positioned on opposed sides of the at least one central stud. The at least one central stud projects past the lateral studs in a first and a second transverse directions extending transversely to a longitudinal center plane of the link member body such that the wear part, when viewed in a plan view, is approximately cruciform.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The invention relates to a link member for tire chains, in particular tire protection chains, comprising a link member body that has at least one connecting opening for additional chain members and comprises a tire contact part and a wear part having lateral studs and at least one central stud.  
         [0002]     Link members are known in which the wear part comprises several essentially identically configured studs between which recesses are provided. The lateral surfaces and the end faces of the link member body extend essentially parallel to one another.  
       SUMMARY OF THE INVENTION  
       [0003]     It is an object of the present invention to configure a link member of the aforementioned kind such that, while a constructively simple configuration is provided, a high wear volume as well as excellent traction are ensured even after an extended service life.  
         [0004]     In accordance with the present invention, this is achieved in that the central stud projects laterally past the lateral studs such that the wear part is approximately cross-shaped (cruciform) in a plan view.  
         [0005]     As a result of the configuration according to the invention, the link member is supported on the ground on four locations that are positioned relative to one another in a cross shape (cruciform); excellent grip and traction are ensured in this way. Moreover, the link member according to the invention has a high wear volume. Advantageously, by means of a substantially rectangular configuration of the connecting openings it is ensured that the linked connecting members can move properly within the link member so that canting is reliably prevented. By providing lateral depressions in the area of the wear part, it is achieved that, after a certain wear has taken place, new profiled edges are formed in the area of the depressions that improve the traction and wear volume again. By arranging additional projections in the area of the wear part, the wear volume can be further increased and traction can be improved. 
     
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0006]      FIG. 1  shows the link member according to the invention in a perspective illustration.  
         [0007]      FIG. 2  shows the link member according to  FIG. 1  in a side view.  
         [0008]      FIG. 3  is a plan view onto the link member according to  FIG. 1  in the direction of arrow III of  FIG. 1 .  
         [0009]      FIG. 4  is a bottom view of the link member according to  FIG. 1  in the direction of arrow IV of  FIG. 1 .  
         [0010]      FIG. 5  shows the link member according to  FIG. 1  in a side view in the direction of arrow V of  FIG. 1 .  
         [0011]      FIG. 6  is a section view along section line VI-VI of  FIG. 2 .  
         [0012]      FIG. 7  is a section view along section line VII-VI of  FIG. 3 .  
         [0013]      FIG. 8  is a section view along section line VIII-VIII of  FIG. 2 .  
         [0014]      FIG. 9  is a section view along section line IX-IX of  FIG. 2 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]     The link member  1  according to  FIGS. 1 through 9  is designed for tire protection chains which are comprised of link members and ring members (not illustrated). The link member  1  has a flat link member body  2  with two connecting openings  3 ,  4  for the ring members of the tire protection chain. The openings  3 ,  4  are positioned sequentially in the longitudinal direction of the link member  1  at a spacing to one another.  
         [0016]     The connecting openings  3 ,  4  have preferably a substantially rectangular contour. This configuration has the advantage that no additional tensile forces are generated when the link member tilts. The edges of the connecting openings are advantageously rounded in order to prevent hooking or catching of the connecting members or ring members on one another.  
         [0017]     The link member  1  has a tire contact part  5  for contacting the tire; the tire contact part  5  delimits the connecting openings  3 ,  4  in the downward direction ( FIG. 2 ). The tire contact part  5  has a somewhat crowned tire contact surface  6  ( FIG. 6 ) with which the link members during use of the tire chain stand on the corresponding tire. The tire contact surface  6  passes across the rounded longitudinal edges  7 ,  8  into lateral walls  9 ,  10  of the link member body  2 , i.e., its tire contact part  5 . This configuration of the tire contact part  5  ensures that the link member can easily roll on the tire without damaging the tire. The lateral walls  9 ,  10  diverge from the tire contact surface  6  in a direction toward the wear part  15 . The tire contact surface  6  passes across part-circular rounded corners  11 ,  12  into the end faces  13 ,  14  of the link member body  2 . As shown in  FIG. 2 , the end faces  13 ,  14  converge in the direction toward the wear part  15 .  
         [0018]     The section of the link member body  2  above the connecting openings  3 ,  4  forms the wear part  15  of the link member  1 . In the illustrated embodiment, the wear part  15  has three studs  16  to  18  that are positioned at a spacing from one another in the longitudinal direction of the link member. Between the lateral studs  16 ,  17  and the central stud  18  there is a recess  19 ,  20 , respectively. The recesses  19 ,  20  each have a rounded bottom  21 ,  22  when viewed in a side view according to  FIG. 2 . In the transverse direction of the link member body  2 , the bottom  21 ,  22  has a pitched roof shape as illustrated in  FIG. 8  for bottom  22 . The bottom sections rise starting at the lateral walls  9 ,  10 , respectively, and pass into one another at half the thickness of the link member body  2  at an obtuse angle. The facing sidewalls  23  and  24 ;  25  and  26  of the neighboring studs  17 ,  18  and  18 ,  16  are also pitched roof shaped (see  FIG. 3 ). The pitched roof shaped sidewalls that laterally delimit the recesses  19 ,  20  thus project in the direction toward the neighboring stud  16  to  18 , respectively. The sidewall sections pass at an obtuse angle into one another at half the thickness of the link member body  2 . The link member body  2  is mirror symmetrical to its longitudinal center plane and its transverse center plane.  
         [0019]     The connecting openings  3 ,  4  are separated from one another by a central stay  31  ( FIGS. 1, 6 , and  8 ) that connects the tire contact part  5  and the wear part  15  at the level of the central stud  18 . The sidewalls  27 ,  28  ( FIG. 6 ) of the central stay  31  have a rounded transition into the sidewalls  30 ,  30  of the connecting openings  3 ,  4  ( FIGS. 1, 2  and  8 ).  
         [0020]     In this way, it is ensured to that the connected chain members can move properly within the connecting openings  3 ,  4  in order to prevent canting of the link member  1  within the ground.  
         [0021]     The end faces  13 ,  14  of the link member body  2  pass across rounded areas  32 ,  33  ( FIG. 2 ) into the wear side of the link member  1  provided at the topside of the studs  16  to  18 . The wear side passes across rounded transition sections  34  through  37  of the studs  16  to  18  into the sidewalls  23  to  26  of the studs  16  to  18  within the recesses  19 ,  20  ( FIGS. 2 and 3 ).  
         [0022]     In a plan view according to  FIG. 3 , the wear part  15  has an elliptical contour. The central stud  18  projects laterally (transversely to the longitudinal center plane of the link member body  2 ) past the two identically configured studs  16 ,  17  so that the wear part  15  is approximately cruciform. In this way, a relatively great division of the link member  1  results so that the corresponding mesh of the tire chain of this four-point configuration becomes larger and a high gripping action and traction are achieved. The central stud  18  has in a plan view approximately a trapezoidal shape ( FIG. 3 ) and tapers in a transverse direction away from the longitudinal center plane of the link member body  2  to both sides. The two lateral studs  16 ,  17  also have approximately a trapezoidal shape but their sidewalls that extend at an acute angle relative to one another have a rounded transition into one another through the end faces  13  and  14  of the link member body  2 . The lateral studs  16 ,  17  widen continuously, starting at the end faces  13 ,  14 , toward the pitched roof shaped sidewalls  23  and  26  that face one another.  
         [0023]     In order to ensure a high grip of the link member  1  even as wear increases, on the lateral surfaces  38  to  41  of the lateral studs  16  and  17  and on the lateral surfaces  42 ,  43  ( FIG. 6 ) of the central stud  18  depressions  44 ,  45 ,  47 ,  48 ,  55 ,  56  are provided, respectively. The depth of these depressions corresponds advantageously approximately to the maximum wear volume of the studs  16  to  18  so that they can be used to a maximum extent. In this way, the link member  1 , despite having the depressions  44 ,  45 ,  47 ,  48 ,  55 ,  56 , has a relatively large wear volume. The lateral depressions  44 ,  45 ,  47 ,  48 ,  55 ,  56  are employed when the studs  16  to  18  are worn to the level of the depressions. As soon as the depressions become effective, new corners and edges are formed in the area of the depressions, and this lead to a great increase of grip.  
         [0024]     While the depressions  44 ,  45 ,  55 ,  56  provided on the lateral studs  16 ,  17  have a closed circumferential contour, the depressions  47 ,  48  provided on the central stud  18  are open in a direction facing the tire contact side  6 . These depressions  47 ,  48  have in a plan view a substantially U-shaped contour.  
         [0025]     In order to further increase traction of the link member  1  with increasing wear, in the area between the depressions  44 ,  45 ,  47 ,  48 ,  55 ,  56  underneath the recesses  19 ,  20  projections  49 ,  50  and  51 ,  52  are provided, respectively, which project past the lateral walls  9 ,  10  of the link member body  2  and extend essentially across the entire height between the connecting openings  3 ,  4  and the recesses  19 ,  20 . The projections  49  to  52  project approximately into the plane of the lateral surfaces  53 ,  54  of the central stud  18 . In this way, the projections  49  to  52  provide upon wear of the studs additional corners and edges that further increase the wear volume and the grip of the link member.  
         [0026]     In order for the engaging edges of the link member  1  to be relatively sharp even upon tilting, the lateral walls  9 , 10  of the link member body  2  extend from the end faces  13  or  14  in the direction toward the center of the link member at an acute angle ( FIG. 3 ), preferably at an angle of approximately 45 degrees.  
         [0027]     The link member  1  described in connection with  FIGS. 1 through 9  has a relatively high wear volume that is achieved by a relatively tall and wide wear part  15  provided with the studs  16  to  18 . The design and the rounded shape of the corners of the link member body  2  ensure proper rolling and prevent canting of the link member. The shape of the connecting openings  3 ,  4  ensures proper movability of the connecting members without causing additional tensile forces to act on them. When the studs  16  to  18  wear down and the grip decreases accordingly, the depressions  44  to  48 ,  55 ,  56  and the projections  49  to  52  become effective. When the studs  16  to  18  are worn down to the area of the depressions and projections, new corners and edges are formed so that grip and also traction of the tire chain is greatly increased. The design of the lateral walls  9 ,  10  of the link member body  2  provides additional grip of the link member  1 . As a result of its high wear volume and its great grip, the link member  1  can therefore ensure even at relatively high wear the required gripping action and traction. Accordingly, the link member  1  is suitable for a plurality of different tire chains that are provided for different applications.  
         [0028]     While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.