Patent Publication Number: US-2011074130-A1

Title: Step board

Description:
TECHNICAL FIELD 
     The present invention relates to a step board, in particular, provided with a braking device to be stable and good in steering and propulsion performance. 
     BACKGROUND ART 
     The step board disclosed in the published Korea Registered Patent No. 800570 (title of the invention: A Step Board) does not have a braking device, so that it has some problems in safety. Also, a conventional step board has non-direction restoring casters which 360-degree rotate and can&#39;t go intended way when they are hit by an obstacle, e.g., cobbles or stones, or run on an unpaved road while a user is on his step board, so that he is thereby also out of balance, thus may fall off his step board or may not go straight on his step board in a desired direction. 
     Also, as such, since the directional caster aforementioned is not of direction restoring performance, it is not easy to use a step board provided with the conventional casters when a user stands on the footholds to generate the force of propulsion. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     The invention was devised to address the aforementioned prior art problems. It is an object of the present invention to provide a safe step board provided with an automatic braking device which operates when a user gets off his step board in order to catch the step board not to continue to run and thus to stop it, and which enables speed to be reduced by loading his weight. 
     It is another object of the invention to provide a step board equipped with direction restoring casters, so that, although the casters do staggered running because of external impact or obstacles, they quickly recover intended direction by means of the force of resilience thereof and which is structured so that a user can easily generate the force of propulsion while standing on the footholds. 
     Technical Solution 
     The step board of the invention in order to achieve the aforementioned object of the invention is characterized in that it comprises a first frame in which a directional caster is equipped at the front end and the back end of a main axis, respectively, a left foothold being extending left upward, and a right foothold extending right upward from the middle of the main axis in length, respectively, a second frame crossing the main axis and extending in the right and left direction, a directional caster being provided at each right and left end of the second frame which is hinge-coupled to the first frame, and a plurality of coil springs one end of which is coupled to the first frame and the other end of which is coupled to the left and right sides of the second frame, respectively. 
     Also, according to a preferred embodiment of the invention, a lug extending upward is formed in the main axis and a projection extends upward from the second frame, the projection and the lug being hinge-coupled. 
     Also, according to another preferred embodiment of the invention, the directional caster is a direction restoring caster equipped with a plural number of coil springs therein so that the wheels return their original state by means of the force of resilience. 
     Also, according to still another preferred embodiment of the invention, each of the direction restoring casters provided on the right and left ends of the second frame is equipped to be widened forward and narrowed backward gradually with respect to the central line of the main axis. 
     Also, according to still another preferred embodiment of the invention, the right and left footholds are formed to have a lower front side than the backside in an inclined way, and the inner side is formed to be lower than the outer side in an inclined way. 
     Also, according to still another preferred embodiment of the invention, the back end of the main axis is provided with a braking means extending toward the side facing away the directional caster equipped at the back end, and positioned toward the ground. 
     Also, according to still another preferred embodiment of the invention, the step board further comprises an automatic braking device which releases braking of the directional caster equipped at the back end of the main axis when a load is given on the right and left footholds and brakes the directional caster equipped at the back end of the main axis when the load is removed. 
     ADVANTAGEOUS EFFECTS 
     The step board of the invention is advantageous in that it is safe to use it in that it is possible to control the speed thereof by means of the braking means. 
     Also, since the step board of the invention is provided with an automatic braking device for automatically braking it when a user gets off the foothold, it is avoided that the step board does not stop and continues to run by means of inertia although the user gets off the footholds. Therefore, collision accidents can be prevented which occur by means of a step board which continues to run by means of inertia or is uncontrollable and the step board of the invention is advantageous in that it addresses the problem that a user has to run to catch the step board running without stopping at a place where he gets it off. 
     Also, the step board of the invention is advantageous in that the direction restoring caster is provided at an angle to be suitable for generating the force of propulsion when the user is on the footholds in order to enhance the force of propulsion. 
     Also, the step board of the invention can quickly recover orientation by means of resilience although the casters run in a staggering way because of external impact or an obstacle while running, so that safety accidents can be avoided which occur when the user loses his balance and may fall off the footholds to be injured. Furthermore, the step board is provided with a resilient object to recover the inclined footholds to the original state for a user to achieve easy stepping and thus to allow running for a long time and at a high speed as desired. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of the present invention will become apparent through the following description, illustrated in the appended drawings, in which like components are referred to by like reference numerals. The various features of the drawings may not be to scale. In the drawings: 
         FIG. 1  is a perspective view illustrating a step board according to the invention; 
         FIG. 2  is a side view of the step board shown in  FIG. 1 ; 
         FIG. 3  is a top view of the step board shown in  FIG. 1 ; 
         FIG. 4  is a perspective view illustrating the state that a foothold cover and a hinge cap are removed in the step board shown in  FIG. 1 ; 
         FIG. 5  is an exploded and perspective view of the step board shown in  FIG. 1 ; 
         FIG. 6  is a front view illustrating the direction in which a directional caster moves when a first frame is inclined toward the left side at the state shown in  FIG. 4 ; 
         FIG. 7  is a front view illustrating the direction in which a directional caster moves when a first frame is inclined toward the right side at the state shown in  FIG. 4 ; 
         FIG. 8  is an exploded and perspective view of a second direction restoring caster shown in  FIG. 1 ; 
         FIG. 9  shows a cross section illustrating the state that braking the automatic braking device of the second direction restoring caster shown in  FIG. 8  is released; and 
         FIG. 10  shows a cross section showing the state that the automatic braking device of the second direction restoring caster shown in  FIG. 8  achieves braking. 
     
    
    
     REFERENCE NUMERALS IN THE FIGURES 
       
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 100: automatic braking device 
                 120: lever 
               
               
                   
                 130: bracket 
                 140: braking axis 
               
               
                   
                 150: coil spring 
                 160: back wheel 
               
               
                   
                 162F: front wheel 
                 162L: left wheel 
               
               
                   
                 162R: right wheel 
                 171: protrusion 
               
               
                   
                 175: caster bolt  
                 200: step board 
               
               
                   
                 210: first frame 
                 211: main axis 
               
               
                   
                 213L, 213R: foothold 
                 220: second frame 
               
               
                   
                 221: projection 
                 223: hinge 
               
               
                   
                 230: compression coil spring 
               
               
                   
                   
               
            
           
         
       
     
     MODE FOR THE INVENTION 
     Hereinafter, preferred embodiments of the step board according to the present invention will be described in detail with reference to the accompanying drawings. 
     In the drawings,  FIG. 1  is a perspective view illustrating a step board according to the invention, and  FIG. 2  is a side view of the step board shown in  FIG. 1 .  FIG. 3  is a top view of the step board shown in  FIG. 1  and  FIG. 4  is a perspective view illustrating the state that the foothold cover and the hinge cap are removed in the step board shown in  FIG. 1 .  FIG. 5  is an exploded and perspective view of the step board shown in  FIG. 1 .  FIG. 6  is a front view illustrating the direction in which a directional caster moves when the first frame is inclined toward the left side at the state shown in  FIG. 4 .  FIG. 7  is a front view illustrating the direction in which a directional caster moves when the first frame is inclined toward the right side at the state shown in  FIG. 4 . Furthermore,  FIG. 8  is an exploded and perspective view of a second direction restoring caster shown in  FIG. 1 .  FIG. 9  shows a cross section illustrating the state that braking of the automatic braking device of the second direction restoring caster shown in  FIG. 8  is released.  FIG. 10  shows a cross section illustrating the state that braking of the automatic braking device of the second direction restoring caster shown in  FIG. 8  is performed. 
     As shown in  FIGS. 1 to 3 , the step board  200  comprises a first frame  210 , a second frame  220 , and compression coil springs  230  for connecting the first and second frames  210  and  220 . 
     The first frame  210  comprises a main frame  211  equipped with a first direction restoring caser  162 F (hereinafter, referred to ‘a front wheel’) at its front end and with a second direction restoring caster  160  (hereinafter, referred to ‘a back wheel  160 ’) at its back end, a left foothold  213 L extending left upward from the middle of the main axis  211  in length, a right foothold  213 R extending right upward from the middle of the main axis  211  in length, and a pair of lugs  215  extending upward from the main axis  211  to allow the second frame  220  to be hinge-coupled between the right and left footholds  213 R and  213 L and the back wheel  160 . 
     The second frame  220  crosses the main axis  211  to extend in the right and left directions and is equipped with a first direction restoring caster (hereinafter, referred to ‘a left wheel  162 L’) at its left end and a first direction restoring caster (hereinafter, referred to ‘a right wheel  162 R’) at its right end. In the middle of the second frame  220  in length, a projection  221  extending upward is hinge-coupled  223  to the lug 215. 
     Two compression coil springs  230  couple the first frame  210  to the second frame  220 , one end of which is fixed to the main axis  211  and the other end of which is connected to the left side and the right side of the second frame  220 , respectively. 
     Therefore, as shown in  FIGS. 4 and 5 , when the first frame  210  is inclined to the left or right side on the basis of the hinge  223  connected to the second frame  220 , the left foothold  213 L and the right foothold  213 R of the first frame  210  inclined are provided with the force of resilience in order to be horizontally placed, while the compression coil spring in the direction in which the first frame  210  is inclined extends and the compression coil spring on the opposite side shrinks. 
     The running principle of the step board  200  configured as described above is the same as that of a step board disclosed in the published Korea Patent Registration No. 800570 (title of the invention: A Step Board), as shown in  FIGS. 6 and 7 . Therefore, detailed description of the running principle of the step board will not be given herein. 
     The step board configured as described above will be described in more detail hereinafter. 
     The lower side of the front end of the first frame  210  and each of the lower sides of the right and left ends of the second frame  220  are equipped with a front wheel  162 F, a left wheel  162 L and a right wheel  162 R, respectively. Covers  164  are provided to hide the bolts and nuts for fixing the front wheel  162 F, the left wheel  162 L and the right wheel  162 R. Foothold covers  217  are provided on top of the left foothold  213 L and the right foothold  213 R so that a user does not slip off while feeling the ground pressure or the cushion effect when he is on the right and left footholds  213 L and  213 R. 
     In addition, the left wheel  162 L and the right wheel  162 R are equipped to be kept at an angle of 10 to 20 degrees by widening forward and narrowing backward gradually with respect to the direction of running, that is, the center line of the main axis  211 . This is because the step board structured as such is superior to a conventional step board in which its left and right wheels are equipped to be in parallel to the main axis, in terms of propulsion performance. 
     Also, the right and left footholds are formed so that the front side thereof is inclined to be about 3 degrees lower than the back side, and the inner side is lower than the outer side to be inclined. This is an ergonomic structure to allow a user easily to incline the first frame  210  in the right and left directions while he is on the right and left footholds  213 R and  213 L and then slightly bends his body. 
     The lug  215  for hinge  223 -coupling the first frame  210  to the second frame  220  is covered with a hinge cover  225 . The hinge  223 -coupling point is where the first and second frames  210  and  220  rotate and it is preferred to cover the point with the hinge cover  225  in order to prevent safety accidents. 
     Furthermore, a braking means  219  made of rubber is formed at the back end of the main axis  211  facing away the back wheel  160  and toward the ground. Therefore, when the user standing on the right and left footholds  213 R and  213 L inclines slightly backward, the braking means  219  contacts the ground while the main axis  211  inclines backward with respect to the right and left wheels  162 R and  162 L. The reason that the braking means  219  contacts the ground when the user inclines backward as described above is because the front wheel  162 F and the right and left wheels  162 R and  162 L form an equilateral triangle. Accordingly, friction occurs while the braking means  219  contacts the ground, so that the running step board  200  decelerates. 
     Hereinafter, characteristics of the automatic braking device  100  and the first and second direction restoring casters will be described in more detail. 
     As shown in  FIGS. 8 to 10 , the automatic braking device  100  comprises a bracket  130  of which the front end is hinge-coupled to the main axis  211  of the step board  200  and which is equipped with the back wheel  160  on its lower side, a lever  120  of which the intermediate portion in length is hinge-coupled to the upper side of the bracket  130  to contact the main axis thus to allow its front end to pivot upward when the lower end goes down, a braking axis  140  positioned to pass through the main axis  211  and the bracket  130  and toward the back wheel  160 , contacting or leaving the back wheel  160  while being across the front end of the lever  120  and simultaneously traveling according to pivoting of the lever  120 , and a coil spring  150  for providing the force of resilience in the direction of pushing the braking axis  140  with the back wheel  160 . 
     More specifically, the front end of the bracket  130  is hinge-coupled to the back end of the main axis  211  so that the back end of the bracket  130  can pivot upward and downward with respect to the main axis  211 . The back wheel  160  is equipped under the lower side of the bracket  130 . Therefore, when the user gets on the right and left footholds  213 R and  213 L, the load is transferred to the back wheel  160  through the main axis  211  while the hinge-coupled bracket  130  pivots toward the main axis  211  by means of the load to release braking. On the contrary, when the user gets off the right and left footholds  213 R and  213 L, the bracket  130  pivots in the direction facing away the main axis  211  by means of the force of resilience of the coil spring  150  while braking is achieved, as will be described hereinbelow in more detail. 
     Furthermore, the lever  120  is equipped on the upper side of the bracket  130 . The intermediate portion of the bracket  130  in length is hinge-coupled to the intermediate portion of the lever  120  in length. The back end of the lever  120  is positioned to contact the lower side of the back end of the main axis  211 . Therefore, when load is transferred to the main axis  211 , the back end of the lever  120  is pressed by means of the main axis  211  and the front end of the lever  120  relatively pivots upward, while the bracket  130  pivots toward the main axis  211 . 
     An aperture  121  is formed at the front end of the lever  120  in the longitudinal direction of the lever  120 . The braking axis  140  is inserted in the aperture  121 . In this case, on the basis of the lever  120 , a first nut  141  is coupled on the upper end of the braking axis  140 . When the front end of the lever  120  pivots upward, the first nut  141  interferes with the front end of the lever  120  to move the braking axis  140  upward. In other words, when load is given to the main axis  211 , the back end of the lever  120  goes down relatively and the front end thereof goes up. While the front end of the lever  120  goes up, the braking axis  140  goes up to face away the back wheel  160 . 
     In addition, the lower side of the bracket  130  is equipped with an upper case  161  of the back wheel  160 . In the upper case  161 , two bearings  163  are stacked. Around the bearings  163 , two semicircular coil springs  165  are placed in a circular shape. The bearings  163  enable the lower case  167  to be able to rotate with respect to the upper case  161  thereof. 
     The lower case  167  of the back wheel  160  is inserted in the upper case  161  in a matching manner. Thereafter, a caster bolt  175  passes through the lower case  167  and the upper case  161  and is then screwed up with a second nut  131  on the upper side of the bracket  130 . 
     As described above, the caster bolt  175  is screwed up with the second nut  131  after passing through the lower case  167  and the upper case  161 , thereby leading to an assembly made of the lower case  167  and the upper case  161 . As shown in  FIGS. 9 and 10 , the back end of the upper case  161  is fixed to the bracket  130 , so that the back wheel  160  is equipped underneath the bracket  130 . 
     In addition, a protrusion  171  is formed on the lower case  167  to be inserted between the two coil springs  165 . The lower case  167  is provided with a pair of flat iron pieces  169  positioned on both sides of the back wheel  160  in parallel. The back wheel  160  is rotatably equipped between the pair of the flat iron pieces  169 . 
     When the direction of the lower case  167  is changed together with the back wheel  160 , the protrusion formed on the lower case  167  presses either of the two coil springs  165  depending on the changed direction. In this case, the force of resilience of the coil springs  165  acts in a restoring manner in the direction in which the back wheel  160  goes straight. Furthermore, while the coil springs  165  shrink at its maximum, the lower case  167  can not rotate any more. Here, the angle at which the lower case  167  can rotate is up to 150 degrees. 
     In addition, the caster bolt  175  is formed with a hollow through which the braking axis  140  passes. The braking axis  140  also passes through the aperture  121  of the lever  120 . The first nut  141  is coupled on the upper end of the braking axis  140  so that the braking axis  140  is caught by the lever  120  without leaving the aperture  121  of the lever  120 . 
     In the hollow of the caster bolt  175 , a straight elastic coil spring  150  is located. While the braking axis  140  passes through the coil spring  150 , the upper end of the coil spring  150  is caught by a stop formed on the inner side of the hollow of the caster bolt  175  and the lower end of the coil spring  150  is caught by a stop  143  formed on the lower side of the braking axis  140 . 
     Hereinafter, the braking mechanism of the automatic brake configured as described above will be described. 
     A user gets on the right and left footholds  213 R and  213 L of the step board  200 . The load is then transferred to the main axis  211 . While the back wheel  160  contacting the ground receives the load, the bracket  130  pivots upward. When the bracket  130  pivots upward, the lower end of the lever  120  equipped on the upper side of the bracket  130  contacts the main axis  211 , relatively causing the front end of the lever  120  to move upward. 
     In this case, the first nut  141  screwed to the upper end of the braking axis  140  interferes with the front end of the lever  120 , so that the lever  120  pushes the braking axis  140  upward to release braking. When the braking axis  140  moves upward, the coil spring  150  encompassing the braking axis  140  is compressed while the force of resilience is generated to push the braking axis  140  toward the back wheel  160 . 
     While braking is released as described above, the user runs on his step board. When he gets in danger in running on his step board and gets off the footholds, the braking axis  140  moves toward the back wheel  160  by means of the force of resilience of the coil spring  150  then to contact the back wheel  160 . In this case, the first nut  141  interferes with the front end of the lever  120  which in turn pivots downward. On the contrary, the back end of the lever  120  pivots upward while pushing the main axis  211  upward to lead to the bracket  130  to pivot downward. 
     As such, while the braking axis  140  contacts the back wheel  160  by means of the force of resilience of the coil spring  150 , friction which contributes to braking occurs between the braking axis  140  and the back wheel  160 . 
     In addition, the front wheel  162 F and the right and left wheels  162 R and  162 L are first direction restoring casters. As compared to the configuration of the back wheel  160 , a second direction restoring caster, the upper case  161  of the front wheel  162 F and the right and left wheels  162 R and  162 L is fixed onto the main axis  211  and the lower side of the right and left footholds  213 R and  213 L, respectively. In the upper case  161 , two bearings  163  are stacked. While the lower case  167  and the upper case  161  are assembled by means of the caster bolt  175 , the protrusion formed on the lower case  167  is inserted between the two semi-circular coil springs  165  positioned around the bearings  163 . 
     Therefore, as the front wheel  162 F and the right and left wheel  162 R and  162 L rotate up to 150 degrees as the back wheel  160  does, the protrusion  171  presses either of coil springs, so that the wheels  162 F,  162 R and  162 L receive the force to be restored by means of the force of resilience of the compressed coil spring. 
     As such, since the front wheel  162 F, the right and left wheel  162 R and  162 L and the back wheel  160  are 150 degrees rotatable direction restoring casters, quick rotation of 360 degrees is quickly achieved when a user intends to rotate his step board with a center at any one of the right and left wheels  162 R and  162 R. 
     Meanwhile, a difference between the front wheel  162 F, the right and left wheels  162 R and  162 L is that the upper case  161  is fixed while being twisted by 10 to 20 degrees with respect to the lower side of the right and left footholds  213 R and  213 L in order to enhance the force of propulsion of the right and left wheels  162 R and  162 L, as described above. 
     The present invention has been described in detail. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     In the claims, any reference numerals placed between parentheses in the claims shall not be construed as limiting the claims. Use of the verb “comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. 
     The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.