Abstract:
Disclosed is an exercise pole ( 1 ) designed for athletes such as walkers, roller skaters, or on-road cross-country skiers. Said exercise pole ( 1 ) comprises an elongate pole body ( 2 ), at one end ( 12 ) of which two wheels ( 41, 42 ) are mounted that allow the exercise pole ( 1 ) to be moved in a directed rolling manner. The wheels ( 41, 42 ) are equipped with a return stop ( 8 ) that allows the wheel ( 41, 42 ) to be rotated in the direction of travel (L) while blocking the same counter to the direction of travel (L) such that pushing off in a forward direction is made possible. The fact that the inventive exercise pole ( 1 ) is in permanent contact with the ground allows the athlete to make smoother and more flowing movements while providing him or her with a greater sense of safety.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention lies in the field of gymnastic exercise apparatus, and relates to an exercise stick for athletes such as walkers, roller skaters or on-road cross-country skiers, according to the introductory part of the first patent claim.  
       BACKGROUND OF THE INVENTION  
       [0002]     The recent type of sport called “Nordic walking” was initially developed as a summer training method for top athletes in the field of marathon, biathlon and Nordic combination. Its popularity has increased greatly in the last years. Today, Nordic walking is performed by a broad public spectrum as an all-season fitness sport. Nordic walking is however not only suitable for fitness exercise, but also for rehabilitation after injuries, operations or disease.  
         [0003]     Nordic walking is a walking or running with the application of special sticks, which are held in each hand of the athlete. Accordingly, the technique of Nordic walking is equivalent to the execution of movement during cross-country skiing. Nordic walking encourages the physiological, diagonal course of movement on walking, by way of the conscious use of the sticks. One advantage compared to conventional walking or running lies in the fact that the muscle system of the arm and of the upper part of the body are also exercised. Furthermore, the body consumes more energy than with conventional walking or running at the same speed.  
         [0004]     The sticks which have been used for Nordic walking up to now are typically manufactured of carbon- and glass fibers (30% carbon composite pole) which ensures a low intrinsic weight, an extreme load capability and a long life duration. In contrast to sticks with a metal core, no disturbing and burdening vibrations are transmitted onto the wrist joints, elbow joints and shoulder joints with the application of such sticks. The optimal stick length is 70% of the body size. Specially designed hand loops at the upper stick end ensure a strain-free application of the sticks over longer periods of exercise. The lower end of the stick should permit a push-off. The lower end of the sticks may be selectively provided with a rubber cushion—for smooth ground such as roads, asphalt, stone—or with a metal tip—for wooded ground and fields, in order to take into account the varying nature of the ground.  
         [0005]     Despite the above-described equipping possibilities for the lower end of the stick, known Nordic walking sticks still have the disadvantage that they slip on the ground and render a push-off impossible. This is particularly the case with hard, smooth ground. The slipping of the sticks disturbs the walking rhythm.  
       SUMMARY OF THE INVENTION  
       [0006]     It is therefore the object of the invention to further develop the known Nordic walking sticks to the extent that they permit an efficient push-off, and a rhythmic, flowing walking or running on any ground.  
         [0007]     The object is achieved by the stick according to the invention, as is defined in patent claim  1 . Advantageous embodiments are specified in the dependent claims.  
         [0008]     The known Nordic walking sticks are finally always directed to the winter sport of cross country skiing, with which the stick is periodically carried over the snow and inserted into the snow. The invention departs from this traditional cross country stick in a radical way and manner. It is based on the idea of providing the lower stick end with one or more wheels. Thus the exercise stick according to the invention may remain in constant contact with the ground. It is no longer necessary to lift it and insert it into the ground with each step. The path of the lower end of the stick is practically a pure translation instead of an up and down hopping movement, as is typical for known sticks. In order to permit a push-off, at least one wheel on the exercise stick according to the invention is provided with a reverse movement block—or with a coupling connected to direction or with a freewheel, which permits a rotation of the wheel in the forwards direction, but blocks it in the reverse direction.  
         [0009]     Accordingly, the exercise stick according to the invention, for athletes, such as walkers, roller skaters or on-road cross country skiers, who travel in the running direction on the ground, comprises an elongate stick body. At least one wheel is attached at one end of the stick body, which permits a directed rolling travel of the exercise stick on the ground. At least one wheel is provided with a reverse movement block which permits a rotation of the wheel in the running direction, but blocks it in the opposite running direction.  
         [0010]     The term “wheel” in this document is to be understood as any means permitting a directed rolling travel. Any forms of disks, rolling parts or rollers are included in this term.  
         [0011]     A slipping-away of the exercise stick to the rear on pushing-off is to be avoided. For this purpose, it is particularly advantageous on the one hand to give the lower end of the stick a certain weight, and on the other hand to design the running surface of the wheels in a manner such that their static friction coefficient with respect to different conceivable ground is as high as possible. By way of this, an as large as possible static friction force is ensured between the wheel and the ground, which as is known, is a product of the normal force and the static friction coefficient.  
         [0012]     The invention revolutionizes Nordic walking by way of making it more effective and at the same time gentler. The course of the movement of the athlete is smoother and more flowing thanks to the exercise stick according to the invention. The exercise effect may be increased or dosed by way of attaching additional weights on the sticks and/or the arms. In contrast to conventional sticks, such additional weights, although resulting in a higher energy consumption, only lead to a small increase in the loading of the joints, since indeed the weight is partly carried by the wheels. The danger of injury for following walkers or runners, which exist with the conventional stick due to the tip of the stick, is eliminated with the stick according to the invention. The constant ground contact gives the athlete increased safety. All these advantages, but in particular the last mentioned one, are of particular value if the exercise stick according to the invention is used for rehabilitation.  
         [0013]     The invention in this document is discussed mainly on account of the application example of Nordic walking. But of course the exercise stick according to the invention may also be applied to other summer sports, such as for skating or on-road cross-country skiing. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     Preferred embodiment examples of the invention are described in a detailed manner by way of the drawings. Thereby, there are shown in:  
         [0015]      FIG. 1  ( a ) an upper part, and ( b ) a lower part of the exercise stick according to the invention, in perspective views,  
         [0016]      FIG. 2  various arrangements of wheels with the exercise stick according to the invention, in schematic perspective views,  
         [0017]      FIG. 3 a  cross section through a reverse movement block on the exercise stick according to the invention, (a) in the freewheel condition as well as (b) in the blocking condition, and  
         [0018]      FIG. 4 a  lower part of a further embodiment of the exercise stick according to the invention. 
     
    
     DETAILED DESCRIPTION  
       [0019]     One embodiment of the exercise stick  1  according to the invention is represented in perspective views in  FIG. 1 , wherein  FIG. 1  ( a ) shows an upper part and  FIG. 1  ( b ) a lower part of the exercise stick  1 . An actual stick body  2  is preferably composed of several, e.g. three segments  21  to  23  which in each case mutually engage in a telescopic manner, in order to permit a length adjustment. The mutual position of the segments  21  to  23  may be fixed in a stepless manner by way of locking rings  24 ,  25  provided with threads. Alternatively, the exercise stick  1  may also comprise other means for the length adjustment and for fixation, such as is known from the state of the art. The stick body  2  could e.g. be composed of two segments and be provided with a collapsing mechanism which permits the two segments to be folded and thus the reduction of the length of the exercise stick  1 . In the condition of use, the two segments are connected to one another in a rigid but releasable manner by way of suitable locking means.  
         [0020]     The stick body  2  may be manufactured from carbon- and glass fibers as is described for the state of the art. Other less expensive materials such as metal, wood, bamboo or plastic are however also possible. In contrast to the state of the art, the exercise stick  1  according to the invention is not restricted to a low intrinsic weight, and the load capability and absence of vibration are of secondary importance thanks to the invention, since the course of movement is smoother and more flowing with the exercise stick according to the invention.  
         [0021]     The upper stick end  11  is equipped with a hand grip  3  and with a hand loop  31 , as are known from the state of the art. Lesser demands with regard to ergonomy and quality are placed on the exercise stick  1  according to the invention, than with sticks according to the state of the art, since the exercise stick  1  according to the invention is merely pulled along the ground, and not lifted or inserted.  
         [0022]     The lower stick end  12  in the embodiment example of  FIG. 1  is provided with two wheels  41 ,  42  which on both sides of the stick body  2  are arranged on a common axle  5 . The axle  5  is rotatably mounted in a bearing  6 , and can be rotated in the running direction L Details with regard to this will be dealt with by way of FIGS.  3 ( a ) and  3 ( b ). The bearing  6  is rigidly connected to the stick body  2 , for example by way of an adapter element  7 . The adapter element  7  is preferably designed such that it may be mounted onto various types of already existing stick bodies  2  available on the market. Thus older sticks may be converted into sticks  1  according to the invention within the context of an add-on solution or retrofit solution, by way of separating the lower stick end ending at the tip, and attaching the adapter element  7  with the bearing  6  and wheels  41 ,  42  instead. Of course independent solutions are also possible, in which the bearing  6  is fastened on the stick body  2  or integrated into it, in a direct manner, without the aid of an adapter element. In an alternative embodiment, the axle  5  may be fastened rigidly in the adapter element  7 , whilst the two wheels  41 ,  42  are each unidirectionally rotatably mounted on the axle by way of a bearing.  
         [0023]     The lower stick end  12 , including the wheels  41 ,  42 , axle  5 , bearing  6  and adapter element  7 , is preferably provided with a larger intrinsic weight than the lower stick ends of conventional sticks. This increases the normal force F N  which the exercise stick  1  exerts on the ground, and contributes to a good ground adherence of the wheels  41 ,  42 . The intrinsic weight of the lower stick end  12  may for example lie in the range between 5 N and 100 N, and preferably between 7 N and 50 N.  
         [0024]     The running surfaces of the wheels  41 ,  42  are preferably manufactured of a material which has an as high as possible static friction coefficient μ o  with respect to the conceivable ground, such as asphalt, stone, gravel, earth, grass, sand etc. This in turn increases the ground adherence and permits a slip-free push-off of the exercise stick  1 . The static friction coefficient μ o  with regard to dry asphalt should be larger than 0.4 and preferably larger than 0.5, for a dry earth path should be larger than 0.3 and preferably larger than 0.4. An ideal material for the running surface appears to be rubber. The wheels  41 ,  42  may for example be designed as solid rubber wheels. The running surface may have a profile or be without any profile.  
         [0025]     The static friction coefficient F R , as is known, is given by 
 
 F   R =μ 0   ·F   N . 
 
         [0026]     On dry asphalt, with the values for the normal force F N  and static friction coefficient μ o  specified above, static friction forces F R  which lie between 3.5 N and 25 N or greater result merely on account of the intrinsic weight of the lower stick end  12 . Added to this is always a perpendicular component of the compressive force F D  (cf.  FIG. 3 ( b )) with which the athlete pushes away on the exercise stick  1  and which increases the normal force F N  and thus also the static friction force F R . The static friction force F R  may be increased yet even more significantly with heavy lower stick ends  12  and additional weights (cf.  FIG. 4 ). The ground adherence may also be improved by way of providing the running surfaces of the wheels  41 ,  42  with suitable profiles, as is known for example for motor car technology.  
         [0027]     The wheel diameter d, the track width w and the number of wheels  41 ,  42  may be very different. It is possible to adapt these parameters to the envisaged type of application with exercise sticks  1  according to the invention. For main use on an asphalted road, one would then select smaller wheels  41 ,  42  with a narrower track width w, whereas somewhat larger wheels  41 ,  42  with a broader track width w are suitable for uneven, wooded ground. The wheel diameters d may e.g. lie in the range between 4 cm and 20 cm, and preferably between 6 cm and 10 cm. Exemplary track widths w may be selected in the region between 3 cm and 30 cm, and preferably between 5 cm and 15 cm.  
         [0028]     The number and arrangement of the wheels with the exercise stick  1  according to the invention is discussed by way of the embodiment which is schematically illustrated in  FIG. 2 . The exercise stick  1  may be equipped with a single wheel or with several, for example up to eight wheels. An exercise stick  1  with a single wheel  41  such as is shown in  FIG. 2 ( a ) has the advantage of a great simplicity and low cost, whereas it provides no lateral stability. Two wheels  41 ,  42  arranged laterally next to one another, as is shown in  FIG. 2 ( b ) or also in  FIG. 1 , stabilize the exercise stick against lateral tilting. In the embodiment example of  FIG. 2 ( c ), four wheels  41  to  44  are arranged behind one another in the running direction L, as it is known from the newer roller skates known as inline skates. FIGS.  2 ( d ) and  2 ( e ) show combinations of wheels  41  to  43  and  41  to  44  which are arranged next to one another and behind one another, respectively. Of course the exercise stick  1  according to the invention may also have more than four wheels, e.g. up to eight wheels.  
         [0029]     The stick body  2  should be pivotable in the plane which is perpendicular to the ground and contains the running direction L. The pivotability is inherently present in the embodiment examples of FIGS.  2 ( a ) and ( b ). A particular mounting  51  for the stick body  2  should be provided on a wheel mounting frame  50  in the embodiment examples of FIGS.  2 ( c ) to  2 ( e ), which permits this pivotability. The man skilled in the art is capable of designing suitable mountings  51  with the knowledge of the invention.  
         [0030]     A reverse movement block  8  which is important to the exercise stick  1  according to the invention is explained with the aid of  FIG. 3 . In the embodiment example of  FIG. 1 , the reverse movement block  8  is installed in the bearing  6 , and acts on the common axle  5  of the two wheels  41 ,  42  rigidly connected to the axle  5 . Alternatively, the axle  5  may also be rigid and the reverse movement block  8  may be attached between the axle  5  and the wheel  41  or  42 . The embodiment example which has been chosen here is a grip roller freewheel which is known per se. The axle  5  is rigidly connected to an inner race  81 , whilst a bearing case  61  is rigidly connected to a roller guide ring  83 . The clamping rollers  82  are located between the inner race  81  and the bearing case  61 , embedded in corresponding recesses in the roller guide ring  83 .  
         [0031]     If the athlete exerts a tensile force F Z  with a non-zero component in the running direction L onto the stick body  2  or the adapter element  7 , as shown in  FIG. 3 ( a ), then the clamping rollers  82  are located in a position which permits an unhindered rotation of the axle  5  with respect to the bearing case  61 . The wheels  41 ,  42 , pulled by the athlete, run forwards on the ground  9  in the running direction L.  
         [0032]     If however the athlete pushes away the exercise stick  1  and thus exerts a compression force F D  with a non-zero component opposite to the running direction L, onto the stick body  2  or the adapter element  7 , as represented in  FIG. 3 ( b ), then the clamping rollers  82  are pressed into wedge-like pockets. In this position, a rotation of the axle  5  with respect to the bearing case  61  is prevented on account of the frictional contact. Thus a reverse rotation of the wheels  41 ,  42  is impossible and the athlete may push off to the front in the running direction L.  
         [0033]     Other reverse movement blocks  8  are also possible, which are known per se, and when required may be adapted to the exercise stick  1  according to the invention by the man skilled in the art. Here a ratchet-type freewheel (with pawl and ratchet), grip freewheel, sprag freewheel, friction freewheel or the tooth freewheel are to be mentioned as further examples of suitable reverse movement blocks.  
         [0034]     The embodiment of  FIG. 4  permits a reversible fastening of additional weights  71 . 1  to  71 . 4  on the lower stick end  12 . The additional weights  71 . 1  to  71 . 4  may e.g. be designed as metal disks, but other forms such as rings or balls are also possible. Each metal disk  71 . 1  to  71 . 4  is provided with a through-opening whose inner shape corresponds to the outer shape of the adapter element  7 , so that they may be attached onto the adapter element  7 . The through-bore may, but need not necessarily be located in the middle of the respective metal disk  71 . 1  to  71 . 4 . In the embodiment example of  FIG. 4 , the through-opening is attached acentrically in an edge region of the metal disk  71 . 1  to  71 . 4 . This has the advantage that in the running position—in which the stick body  2  is not perpendicular to the ground, but is inclined to the front (in the running direction L or in the direction of the static friction force F R )—the center of gravity of the additional weights  71 . 1  to  71 . 4  and thus also of the lower stick end  12  lies as low as possible. Thus the wheels  41 ,  42  acquire optimal ground contact as quickly as possible again given unevenness of the ground. A rail  72  or other guide- and fixation means may be provided at the lower stick end  12  or on the adapter element  7 , for the improved guidance on assembly and for the improved fixation of the additional weights  71 . 1  to  71 . 4 . Furthermore fastening means (not shown) for the reversible fastening of the additional weights  71 . 1  to  71 . 4  may be present at the lower stick end  12  or on the adapter element  7 .  
         [0035]     An additional weight  71 . 1  to  71 . 4  may weigh e.g. between 5 N and 20 N or 10 N. The number of additional weights  71 . 1  to  71 . 4  or their total weight may be selected according to the requirement and the performance of the athlete. A total weight of the lower stick end  12  of up to 200 N is indeed realistic. On the one hand the normal force F N  is increased, and thus the static friction force F R  is further increased with such additional weights  71 . 1 - 71 . 4 . On the other hand, the additional weights  71 . 1  to  71 . 4  permit the exercise effect to be increased or to be dosed in an individual manner. This permits new exercise possibilities which are excluded with conventional sticks. Conventional sticks are constructed in an as lightweight as possible manner in order not to overload the wrist joints of the athlete.  
       LIST OF REFERENCE NUMERALS  
       [0000]    
       
           1  exercise stick  
           11  upper end of the exercise stick  
           12  lower end of the exercise stick  
           2  stick body  
           21 - 23  segments of the stick body  
           24 ,  25  locking rings 
         3  hand grip      
           31  carrier loop  
           41 ,  42 ,  43 ,  44  wheels  
           5  axle  
           50  wheel mounting frame  
           51  mounting for stick body  
           6  bearing  
           61  bearing case  
           7  adapter element  
           71 . 1 ,  71 . 2 ,  71 . 3 ,  71 . 4  additional weights  
           72  rail  
           8  reverse movement block  
           81  inner race  
           82  clamping rollers  
           83  roller guide ring  
           9  ground  
          d wheel diameter  
          F D  compressive force  
          F N  normal force  
          F R  static friction force  
          F Z  tensile force  
          L running direction  
          w track width  
          μ o  static friction coefficient