Patent Publication Number: US-2005116539-A1

Title: Walking wheel for bicycle

Description:
BACKGROUND OF THE PRESENT INVENTION  
      1. Field of Invention  
      The present invention relates to a bicycle, and more particular to a walking wheel comprising a plurality of walking elements discretely arranged around a hub, wherein the walking elements are capable of rotating in a stepping-like manner.  
      2. Description of Related Arts  
      Bicycles are heavily relied on many people as means for transportation or exercising and entertaining equipment. A basic bicycle includes a bicycle frame, steering assembly, transmission assembly, brake assembly and two wheels. The bicycle frame is usually made in a diamond shape with a front fork and back fork for receiving a front and rear wheels, respectively. The steering assembly is usually a T-shaped handlebar extended from the front fork in a manner suitable for a rider to lay his/her hands on. The transmission assembly includes a front sprocket, rear sprocket, chain and a pair of paddles. The paddles are coaxially secured to the center of the front sprocket, which, through the chain, is connected to the rear sprocket that is coaxially affixed to the rear wheel. A rider may step on the paddles to rotate the front sprocket, and the rotation movement is transmitted through the chain to the rear sprocket to rotate the rear wheel and drive the bicycle moving forward. The brake assembly usually includes a pair of brake levers, brake cables and brake pads. The brake pads are secured adjacent to the front and rear wheels, respectively, and connected to the brake levers via the brake cables. A rider may squeeze the brake levers and the handlebars to pull the brake cable to press the brake pads against the wheels for braking.  
      Traditionally, a bicycle wheels is constituted of a hub, rim, inflatable tire and a plurality of spokes. The spokes radically extends from the hub to the inner side of the rim. The inflatable tire is disposed around the rim and a chamber is formed therebewteen, into which pressured air is pumped to keep the tire inflated. The bicycle wheel is disposed between the two branches of the fork and rotatably connected therebetween.  
      The inflated tire sustains the weight of the bicycle and provides a contact surface with the ground for generation of fiction. Because the contacting area between the tire and ground bears the weigh of the bicycle, the pressure in the contacting area is greater than any other areas of the tire. The pressure forms a contacting area between the tire and ground, where friction is thereby generated. As a rider steps on the paddles, the transmission assembly transforms the stepping movement into rotating movement for the wheel, wherein the contacting area works as a pivot point to pivotally move the hub forward via the spokes as the leverage. As the hub moves forward, the spokes in turn rotate the current contacting area departing from the ground and replace it with the adjacent surface of the tire. Although how the tire contacts with the ground may sound discrete, it actually works in a continuous way.  
      A drawback of the traditional bicycle tire is its inability of accommodating the difficult terrain, such as rough, rocky, sandy, muddy and bumpy roads. One reason for that is the rather limited contacting area between the tire and ground. When the tire is proper inflated, the weight of the bicycle plus average loading would deform the tire a little bit and generate a rather great pressure to the ground. Say, if a person rides the bicycle on a muddy road, the pressure between the tire and the round would make the wheel easily sink into the muddy road, and a lot of efforts of moving the bicycle forward would be wasted. The softness and liquidness of the muddy road provides insufficient reaction force to properly deform the tire for a contacting area with adequate fraction generated. A part of the energy spent for rotating the wheel would be wasted in deforming the muddy road under the tire instead of generation sufficient friction for the bicycle going forward.  
      One solution to the abovementioned drawback can by found in a United States patent Application Publication numbered as U.S. 2001/0007388. It discloses a bicycle designed for riding on all-terrain with unconventional wheels, each of which has a circular rim that is interconnected to a hub by spokes. A surface engaging support shoes assembly is attached on the rim to provide support of the bicycle on a surface, wherein each engaging support shoe of the assembly is discontinuous and capable of pivotal movement with respect to the rim so that the assembly keeps better contact with the ground than traditional tires when the bicycle is moving.  
      Some feature of the abovementioned bicycle limits its ability of accommodating very difficult terrain. First, only one pivotal joint is provided between the engaging support shoe and the rim. This prevents each engaging support shoe from further adjusting its contacting surface with the ground to optimize the contacting area for better generation of friction. Second, because the engaging support shoes assembly is pivotally attached around the rim, in order to avoid the rim contacting with the ground directly, the engaging support shoes must be arranged in a close manner. In other words, the wheel employing the engaging support shoes assembly rotates more like traditional wheels and therefore cannot overcome an obstacle by stepping on top of it like a human being does. Third, the wheel has no suspension mechanism on it, so that the shock would be transferred directly from the ground through the wheel to the bicycle frame.  
      How to absorb the shock from the ground to the wheel is an important issue to the technical field of wheels. Such shock-absorbing wheel, albeit not necessarily used in bicycles, may be found in a United States patent numbered as U.S. Pat. No. 4,420,192, wherein a wheel having two staggered rows of surface-gripping, radially-yielding feet. When the wheel encounters an obstacle, a spring compresses, thereby permitting the feet to deflect and absorb shock that would have otherwise been impacted to the vehicle.  
      The abovementioned wheel may have many “feet” members, but it does not function like the stepping movement a human being does, which is known as one of the most ingenious natural mechanism in terms of overcoming obstacles. The stepping movement requires a pivotal joint connecting the leg to the heel and another pivotal joint connecting the heel to the toe. When a person is walking, the heel lands on the ground first and the leg moves forward to place the body weight on the toe, and the heel leaves the ground by using the toe as a pivotal point to move the leg further forward. However, the abovementioned “foot” of the wheel does not have joints like a real foot of human being. The contact surface of the “foot” is a piece of solid rubber without any mechanism like the interaction of toe and heel of a human foot. Thus, it may not functions as good as a human foot in terms of overcoming obstacles.  
     SUMMARY OF THE PRESENT INVENTION  
      A main objective of the present invention is to provide a walking wheel comprising a plurality of walking elements discretely and coaxially disposed around a hub to form a wheel-like discontinuous arrangement of walking surfaces that are capable of adjusting their contacting areas with the ground so that the gripping of the walking wheel with respect to the ground is therefore enhanced.  
      Another objective of the present invention is to provide a walking wheel comprising a plurality of walking elements discretely disposed around a hub via corresponding supporting members, wherein the walking element currently contacting with the ground provides friction for moving the hub forward to rotate the next walking element to step on the ground and lift the current walking element so that the walking wheel is capable of imitating stepping movement of human beings that is particularly suitable to ill-conditioned terrain over the conventional tires.  
      Another objective of the present invention is to provide a walking wheel comprising a walking element substantially constituted of a toe portion and heel potion capable of pivotal movement with respect to each other, wherein the heel portion is predominately in contact with the ground as the walking element is arriving the ground and the toe portion is predominately in contact with the ground as the walking element is departing the ground, so that the walking element is able to move on the ground in a stepping-like manner, which always keep the walking element in good contact with the ground in a balanced way.  
      Another objective of the present invention is to provide a walking wheel comprising a walking element with a suspension device to absorb impact generated when the walking element is arriving and departing the ground so as to keep the walking wheel moving stable on difficult terrain.  
      Another objective of the present invention is to provide a walking wheel comprising walking elements with aesthetic dressing for appearance of entertainment, fashion and uniqueness.  
      Another objective of the present invention is to provide a bicycle adopting the abovementioned walking wheels so as to enable the bicycle to move on difficult terrain and convey the appearance of entertainment, fashion and uniqueness.  
      One embodiment of the present invention discloses a walking wheel for a bicycle riding on a ground surface, comprising: a hub for rotatably mounting to said bicycle; a plurality of supporting members outwardly extended from said hub; a plurality of walking elements connected to said supporting members respectively, wherein each of said walking elements has a stepping surface defining a toe portion and a heel portion flexibly extended therefrom, wherein said stepping surfaces of said walking elements are coaxially aligned to said hub in a toe-to-heel manner to form a discrete driving surface in such a manner that when said hub is driven to rotate, one of said walking elements is arranged for stepping on said ground surface in a human toe-heel walking manner that said heel portion of said stepping surface of said following walking element steps on said ground surface when said heel portion of said stepping surface of said preceding walking element lifts up from said ground surface.  
      Another embodiment of the present invention discloses a bicycle for riding on a ground surface comprises: a bicycle frame for structural sustention; a steering assembly for steering said bicycle frame to a certain direction; two walking wheels comprising: a hub for rotatably mounting to said bicycle frame; a plurality of supporting members outwardly extended from said hub; a plurality of walking elements connected to said supporting members respectively, wherein each of said walking elements has a stepping surface defining a toe portion and a heel portion flexibly extended therefrom, wherein said stepping surfaces of said walking elements are coaxially aligned to said hub in a toe-to-heel manner to form a discrete driving surface; and a transmission system for receiving and transferring input energy to drive at least one of said walking wheels in such a manner that when said hub is driven to rotate, one of said walking elements is arranged for stepping on said ground surface in a human toe-heel walking manner that said heel portion of said stepping surface of said following walking element steps on said ground surface when said heel portion of said stepping surface of said preceding walking element lifts up from said ground surface.  
      These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a bicycle employing walking wheels according to one preferred embodiment of the invention.  
       FIG. 2  is a front view of the waking wheel according to the preferred embodiment of the invention.  
       FIG. 3  is a front view of the hub of waking wheel according to the preferred embodiment of the invention.  
       FIG. 4  is a top view of the hub of walking wheel according to the preferred embodiment of the invention.  
       FIG. 5  is a cross-sectional view of the walking element connected with the supporting member of the walking wheel according to the preferred embodiment of the invention.  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Referring to  FIG. 1 , a perspective view of a bicycle  10  that employs the walking wheels  20  according to a preferred embodiment of invention is illustrated. The bicycle  10  comprises a bicycle frame  30 , steering assembly  40 , transmission assembly  50 , brake assembly  60  and walking wheels  20 . A front walking wheel  21  is secured at a front portion of the bicycle frame  30  in a rotating manner and a back walking wheel  22  is secured at a rear portion of the bicycle frame  30  in a rotating manner. The steering assembly  40  is mechanically connected to the front walking wheel  21  for steering the bicycle  10 . The transmission assembly  50  is mechanically connected to the rear walking wheel  22  for transmitting input kinetic energy to drive the rear walking wheel  22  for rotation. The brake assembly  60  is provided for stopping the movement of the bicycle.  
      The bicycle frame  30  comprises a front fork  31 , rear fork  32 , main frame  33  and seat  34 . The main frame  33 , which is made in a diamond shape, comprises a first elongated bar  331  and second elongated bar  332  connected with each other, substantially defining the operating space for a bicycle rider. The front fork  31 , constituted of a first front branch  311  and second front branch  312 , downwardly extends from a far end of first elongated bar  331  with respect to the seat  34 . Likewise, the rear fork  32 , constituted of a first rear branch  321  and second rear branch  322 , downwardly extends from a top end of the second elongated bar  332 .  
      The front walking wheel  21  is rotatably secured between the first front branch  311  and second front branch  312  along its axis, and the rear walking wheel  22  is rotatably secured between the first rear branch  321  and second rear branch  322  along its axis. The seat  34  is securely mounted on top of the second elongated bar  332  for sitting the rider thereon. In addition, the second elongated bar  332  is a hollow cylinder into which a seat bar  341  protruded from the seat  34  is inserted, so that the height of the seat  34  is adjustable by moving the seat bar  341  along within the second elongated bar  322  and secure them together for a desirable height for the seat  34 . It is noted that another structure may be provided for the bicycle frame without departing the spirit of the invention.  
      The steering assembly comprises a T-shaped steering handlebar  41  and two handle surfaces  42  are provided on the two ends of the horizontal part of the T-shaped steering handlebar  41  for ease of gripping by the rider. The T-shaped steering handle bar  41  is fixedly connected to the front fork  31  in such a manner that the front fork  31  and front walking wheel  21  may be turned clockwise or counter-clockwise by virtue of maneuvering the handlebar  41 . The handle surfaces  42  are two flexible tubes fitted at the two ends of the horizontal part of the T-shaped steering handlebar  41 . A certain pattern is provided on the handle surfaces  42  for increasing the friction between the rider&#39;s hand and the handle surfaces  42 .  
      The transmission assembly  50  comprises a front sprocket  51 , rear sprocket  52 , chain  53 , a pair of paddles  54  and a pair of leverages  55 . The front sprocket  51  is rotatably mounted at the junction of the first elongated bar  331  and second elongated bar  332 . The pair of paddles  54  is connected to the front sprocket  51  via the leverages  55  in such as manner that the stepping movement of the paddles  54  can be transferred into rotating movement of the front sprocket  51 . The front sprocket  51  is connected to the rear sprocket  52  via the chain  53 , and the teeth of the front sprocket  51  drive the chain  53  to move in a loop manner that in turn drives the rear sprocket  52  to rotate by virtue of the engagement of teeth therebetween. The rear sprocket  52  is coaxially secured to the rear walking wheel  52 , so that the rotation movement of the rear sprocket  52  drives the rear walking wheel  52  to rotate. It is noted that the front sprocket  51  and rear sprocket  52  may be made as sets of sprockets to provide various gears.  
      The brake assembly  60  comprises a hand brake lever  61 , cable  62 , brake pad  63  and disc  64 . The brake lever  61  is connected to the brake pad  63  through the cable  62 . The brake pad  63  is disposed adjacent to the surface of disc  64 , which is coaxially secured to the rear walking wheel  52 . A rider may squeeze the brake lever  61  with respect to the T-shaped steering handlebar  41  to pull up the cable  62  to press the brake pad  63  against the disc  64 , and the friction between the brake pad  63  and disc  64  may gradually stop the rotation movement of the rear walking wheel  22  for braking. It is noted that the brake assembly  60  can be provided for both the front walking wheel  21  and rear walking wheel  22  for better braking effect.  
      Referring to  FIG. 1  and  FIG. 2 , a side view of the walking wheel  20  according to the preferred embodiment of the invention is illustrated. The walking wheel  20  comprises a hub  24 , a plurality of supporting members  25  outwardly extended from the hub  24 , and a plurality of walking elements  26 . The hub  24  has an axial slot  27  passing through its center for receiving a bolt to rotatably mount the walking wheel  20  to the bicycle frame  30 . When the transmission assembly  50  drives the rear walking wheel  22  to rotate, the contacting area between the walking element  26  and ground provides a friction as a pivot point for moving its corresponding supporting member  24  forward, such that the rotation movement of the walking wheel  22  is transferred into the linear movement of the bicycle  10 .  
      Referring to  FIG. 3  and  FIG. 4 , the hub  24  comprises a body  241 , in which a plurality of radial slots  242  is formed, and a protruded portion  243  is illustrated. The body  241  is made in a cylinder shape, around the outer circumferential surface of which a plurality of the radial slots  242  are spacedly provided for receiving the supporting members  25  (see  FIG. 2 ). Each of the radial slots  242  has an elongated portion  244  that has a diameter slightly greater than that of the supporting member  25 , and a funnel-like receiving portion  245  outwardly extending from the elongated portion  244  for ease of inserting the supporting member  25  into the elongated portion  244 . The supporting member  25  is affixed within the radial slot  242  by means of wielding. It is noted that the supporting members  25  and hub  24  may be formed integrally, or connected by means, like bolt-and-nuts, screws, rivets and adhesive.  
      The front surface  246  of protruded portion  243  has a thickness T from the front surface  247  of body  241  for avoiding substantial interference between the front surface  247  and front fork  31  or rear fork  32 , when the waking wheel  20  is rotatably secured therebetween. In this preferred embodiment, the protruded portion  243  is integrally formed on the front side of the body  241  of hub  24 . It is noted that the protruded portion may be a foreign part coaxially attached to the axial slot  27  on the font surface  247  of body  241  by virtue of welding or adhesive.  
      Referring to  FIG. 2  and  FIG. 5 , a cross-sectional view of the walking element  26  connected with the supporting member  25  of walking wheel  20  according to the preferred embodiment of the invention is illustrated.  
      Each of the walking elements  26  has a stepping surface  266  with non-slipping treatment thereon to better gripping between the stepping surface  266  and the ground surface. The stepping surface  266  of the walking element  26  has a predetermined curvature to from an arc of the discrete driving surface of walking wheel  20 . The stepping surfacing  266  defines a toe portion  267  and a heel portion  268  flexibly extended therefrom. The stepping surfaces  266  of the walking elements  26  are coaxially aligned to the hub  24  in a toe-to-heel manner to form a discrete driving surface with respect to the hub  24 .  
      Therefore, when the hub  24  is driven to rotate, one of the walking elements  26  is arranged for stepping on the ground surface in a human toe-heel walking manner that the heel portion  268  of stepping surface  266  of the following walking element  26  steps on the ground surface when the heel portion  268  of stepping surface  266  of preceding walking element  26  lifts up from said ground surface.  
      Each of the supporting members  25  comprises an elongated supporting leg having an inner end  252  radially extended from the hub  24  and an outer end  253  pivotally connected to the respective walking element  26 . The supporting member  25  further comprises an ankle joint  254  coupling the supporting leg  251  with the respective walking element  26 .  
      Accordingly, the ankle joint  254  comprises two resilient elements, toe spring element  255  and heel spring element  256 , coupling the supporting leg with the toe portion  267  and the heel portion  268  respectively for applying an urging pressure against walking element  26  to regularly maintain the stepping surface  266  in a curved-shape. Either toe spring element  255  or heel spring element  256  comprises a first extension rod  257 , second extension  258  and spring  259 . The first extension rod  257  is connected to the supporting leg  251  with its one end and to the spring  259  with another end. Likewise, the second extension rod  258  is connected to the walking frame  262  with its one end and the spring  255  with another end. The spring  259  is flexible along its longitudinal direction and rigid enough to resist deformation at its transverse direction.  
      Each of the walking elements  26  comprises a walking frame  262 , having an arc-shape, pivotally connected to the respective supporting member  25 , and a shoe  265  having a bottom non-slipping surface  261  as the stepping surface  266 , wherein the shoe  265  is replaceably worn at the walking frame  262  to reinforce the curvature of the stepping surface  266  of the shoe  265 , as shown in  FIG. 5 . In other words, the driver is able to replace his or her shoe  265  to form the walking wheel of the present invention while the arc-shaped walking frame  262  is adapted to reinforce the bottom surface  261  of the shoe  265  to be bent at the curvature of the stepping surface  266  of the walking element  26 .  
      As shown in  FIG. 2 , the walking wheel further comprises a plurality of guiding elements  28  connecting the walking elements  26  respectively, wherein each of the guiding elements  28  has two ends respectively connecting the toe portion  267  of the preceding walking element  26  to the heel portion  268  of the following walking element  26  so as to alignedly guide the walking elements  26  in a toe-to-heel manner. Accordingly, each of the guiding elements  28  is embodied as a short metal chain. It is noted that the guiding element  28  could also be a rope or string to connect between each two walking elements  26 .  
      How the walking element  26  works is explained as the following. When the walking element  26  is arriving the ground, the heel potion  268  lands the ground first. At this moment, a contacting area is formed between the heel portion  268  of walking element  26  and the ground. The friction between the heel portion  268  and the ground works as a pivot point for the hub  24  with the supporting member  25  as the leverage so as to move the hub  24  forward. As the hub  24  is moving forward, the weight of the walking wheel  20  and bicycle  10  shifts along with the forward movement, so as to push the toe portion  267  contacting with the ground. When the walking element  26  is departing the ground, the friction between the toe portion  267  and the ground provides as a pivot point for the hub  24  with the supporting member  25  as the leverage, so as to lift the heel potion  268  from the ground. At this point, resilient elements  255  and  256  absorb the shock from the ground. Then, the hub  24  keeps moving forward until the toe portion  267  departs from the ground, so as to complete a stepping movement for a walking element  26 .  
      It is noted that there is only one circular row of walking elements are provided for a walking wheel, two or more rows of walking elements  26  that are arranged either staggeredly or alignedly can be employed without departing the spirit of the invention.  
      The disclosed walking element provides the following advantages. First, because the walking elements  26  discretely disposed around the hub  24  to form a wheel-like discontinuous arrangement of steeping surfaces  266  that are capable of adjusting their contacting areas with the ground for arriving and departing stages, the gripping of the walking wheel  20  with respect to the ground is therefore enhanced in response to the shift of the carried weight of the walking wheel. Second, the walking wheel  20  is capable of imitating stepping movement of human beings that is particularly suitable to ill-conditioned terrain over the conventional tires. Third, the walking element  26  is able to move on the ground in a stepping-like manner, which always keeps the walking element  26  in good contact with the ground in a balance way, especially when it is used in difficult terrain, like muddy or rocky road. Fourth, the resilient elements  255  and  256  are capable of absorbing impact generated when the walking element  20  is arriving and departing the ground so as to keep the walking wheel moving stable on difficult terrain. Fifth, the shoe replace  265  conveys the appearance of entertainment, fashion and uniqueness.  
      One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting.  
      It will thus be seen that the objects of the present invention have been fully and effectively accomplished. It embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.