Patent Publication Number: US-8523211-B2

Title: Knee roller

Description:
TECHNICAL FIELD 
     The disclosure generally relates to the field of ambulatory assistive devices, particularly to a self-propelled knee roller. 
     BACKGROUND 
     Various devices may be utilized to provide walking assistance to a person with physical impairments. A knee roller (may also be referred to as a knee walker or knee scooter) is one of such devices that provides support for a knee, allowing the person to rest one leg on the knee roller and utilize the other leg to propel the knee roller. 
     Many of the existing devices include one or more front wheels, one or more rear wheels and a cushion positioned between the front and rear wheels for supporting the knee. The front wheels in such a device may be steerable (e.g., using a handlebar) and the rear wheels may follow, allowing the user to guide the device towards a particular direction. However, the turning abilities provided in such configurations are limited (e.g., having a turning radius of a few meters), making such devices difficult to navigate and/or turn in small areas. Therein lies a need for a knee roller that is easy to use and provides improved maneuverability. 
     SUMMARY 
     The present disclosure is directed to a knee roller that is easy to use and provides improved maneuverability. The knee roller may include a support frame for supporting a handlebar assembly, a knee support and a pair of coaxial wheels. The pair of coaxial wheels may be positioned below the knee support, where the pair of coaxial wheels rotates about a common rotation axis, and a vertical plane defined by the rotation axis intersects the knee support. The position of the pair of coaxial wheels with respect to the knee support substantially distributes a weight received at the knee support over the pair of coaxial wheels and allows the knee roller to turn about a vertical axis perpendicular to and intersects with the rotation axis. 
     Furthermore, the position of the pair of coaxial wheels with respect to the knee support positions the vertical plane defined by the rotation axis to generally coincide with a coronal plane of the user. The position of the pair of coaxial wheels with respect to the knee support also provides zero turning radius capabilities, allowing the user to turn about a vertical axis formed by an intersection of the coronal plane of the user and a sagittal plane of the user (i.e., turn/spin around). Maneuverability is therefore improved. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not necessarily restrictive of the present disclosure. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate subject matter of the disclosure. Together, the descriptions and the drawings serve to explain the principles of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The numerous advantages of the disclosure may be better understood by those skilled in the art by reference to the accompanying figures in which: 
         FIG. 1  is an isometric view of a knee roller in accordance with the present disclosure; 
         FIG. 2  is a top view of the knee roller; 
         FIG. 3  is an illustration depicting the knee roller being utilized; 
         FIG. 4  is a side elevation view of the knee roller; and 
         FIG. 5  is an illustration depicting maneuverability of the knee roller in accordance with the present disclosure in comparison with a conventional device. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the subject matter disclosed, which is illustrated in the accompanying drawings. 
     The present disclosure is directed to a knee roller that is easy to use and provides improved maneuverability. Certain anatomical terms are used in the present disclosure to describe locations and movements relevant to a human body. More specifically, a coronal plane (also known as the frontal plane) is an anatomical term referring to a vertical plane that divides the body into ventral and dorsal (belly and back) sections. In addition, a sagittal plane is an anatomical term referring to a vertical plane which passes from front to rear dividing the body into right and left sections. 
     Referring generally to  FIGS. 1 through 4 , a knee roller  100  in accordance with the present disclosure is shown. The knee roller  100  may include a support frame  102 , a handlebar assembly  104 , a knee support  106  and a pair of coaxial wheels  108  positioned below the knee support  106 . The position of the pair of coaxial wheels  108  with respect to the knee support  106  allows the rotation axis  110  of the wheels  108  to generally coincide with the coronal plane  112  of the user during operation, and also allows the weight received at the knee support  106  to be substantially distributed over the pair of wheels  108 . Such an arrangement allows the knee roller  100  to feel more natural to the user and allows the user to turn about a vertical axis formed by the intersection of the user&#39;s coronal plane  112  and sagittal plane  114 . 
     In one embodiment, the handlebar assembly  104  may be adjustably attached to the support frame  102 , allowing the height of the handlebar to be adjustable for different users. For instance, the handlebar assembly  104  may include a support rod with predefined apertures, and a pin may be utilized to engage one of the apertures in order to lock the handlebar assembly  104  at a desired height. Similarly, the knee support  106  may also be adjustably attached to the support frame  102 , allowing the height of the knee support to be adjustable for different users. It is contemplated that various other types of mechanisms may be utilized to provide height adjustments for the handlebar assembly  104  and/or the knee support  106  without departing from the spirit and scope of the present disclosure. 
     As illustrated in the figures, the pair of coaxial wheels  108  is attached to the support frame  102  at a position below the knee support  106 . In addition, the wheels  108  are configured to rotate about a common rotation axis  110 , and a vertical plane defined by the rotation axis  110  intersects with the knee support  106 . That is, in accordance with the present disclosure, the wheels  108  are positioned underneath (with respect to the orientation indicated in  FIG. 1 ) the knee support  106 . In a preferred embodiment, the vertical plane defined by the rotation axis  110  may intersect with the knee support  106  within a few (e.g., within 4) inches from the center of the knee support  106  (indicated as d 1  in  FIG. 4 ). Furthermore, the lateral distance (with respect to the orientation indicated in  FIG. 4 ) between the handlebar assembly  104  and the center of the knee support  106  (indicated as d 2  in  FIG. 4 ) may be configured to be less than or about the length of the user&#39;s forearm (or about 7 to 15 inches), allowing the user to comfortably rest the arms on the handlebar when using the knee roller  100 . 
     The position of the wheels  108  with respect to the knee support  106  allows the vertical plane defined by the rotation axis  110  to generally coincide with the coronal plane of the user when the user places a knee on the knee support  106  (as shown in  FIGS. 3 and 4 ). This arrangement makes the knee roller  100  feel more natural to the user as the knee support  106  and the wheels  108  together provide an extension from the user&#39;s thigh, allowing the weight received at the knee support  106  to be substantially distributed along this extension. 
     This arrangement also provides improved maneuverability for the user when using the knee roller  100 . As illustrated in  FIG. 5 , instead of utilizing front wheels  202  to guide the path as in a conventional roller  200 , the knee roller  100  in accordance with the present disclosure does not utilizes such front wheels, and the handlebar assembly  104  is configured to be non-pivotal relative to the support frame  102 . The knee roller  100  in accordance with the present disclosure is configured to respond to the propulsion provided by the user and is able to turn about a vertical axis perpendicular to and intersects with the rotation axis  110 . Therefore, zero turning radius is achieved, which may be appreciated in various situations. 
     For instance, in situations where available space may be limited, the knee roller  100  in accordance with the present disclosure may allow the user to navigate around tight corners or the like. In another example, the user utilizing the knee roller  100  is able to turn around without having to circle around as the case with a conventional device. That is, the knee roller  100  allows the user to turn about a vertical axis formed by the intersection of the user&#39;s coronal and sagittal planes (i.e., turn/spin around). Furthermore, the knee roller  100  in accordance with the present disclosure does not require any upper body movement in order to properly operate the roller. The rotation axis  110  of the wheels  108  stays generally parallel with the user&#39;s shoulders during operation and the user may keep the upper body position unchanged even when turning. 
     It is contemplated that one or more auxiliary wheels may be utilized to provide additional support if needed. In one embodiment, two auxiliary wheels,  116  and  118 , are positioned towards the front and the rear of the support frame  102 , respectively. As illustrated in  FIG. 4 , the auxiliary wheels  116  and  118  are configured to conditionally engage the ground  120 . More specifically, when the knee roller  100  is held straight up, the auxiliary wheels  116  and  118  may be suspended above the bottom of the coaxial wheels  108  where the coaxial wheels  108  engage the ground  120 , and the weight received at the knee support  106  may be distributed entirely over the coaxial wheels  108 . 
     However, the user may lean slightly forward (e.g., when propelling the knee roller  100  forward), in which case the knee roller  100  may also lean slightly forward, allowing the auxiliary wheel  116  to engage with the ground  120  and to swivel based on the direction of travel of the knee roller  100 . Utilizing the auxiliary wheel  116  may help preventing the knee roller  100  from inadvertently tipping forward. Similarly, the user may lean slightly backwards, in which case the knee roller  100  may also lean slightly backwards, allowing the auxiliary wheel  118  to engage with the ground  120  and to swivel based on the direction of travel of the knee roller  100 . Utilizing the auxiliary wheel  118  may help preventing the knee roller  100  from inadvertently tipping backward. 
     It is contemplated that the two auxiliary wheels depicted in the figures are merely exemplary. Fewer or additional auxiliary wheels may be utilized. It is also understood that the particular type of auxiliary wheels depicted in the figures is merely exemplary. Various types of swivel wheels may be utilized without departing from the spirit and scope of the present disclosure. Furthermore, the ground  120  referenced in the description above generally refers to a plane that the coaxial wheels  108  and the auxiliary wheels  116  and  118  may engage. It is understood that different surface conditions may provide slightly different riding conditions. For instance, if the knee roller  100  is utilized on a soft surface (e.g., carpet or the like), the auxiliary wheels  116  and  118  may contact the surface even when the knee roller  100  is held straight up. 
     It is further contemplated that one or more tilt prevention arms may be utilized to help preventing the knee roller  100  from inadvertently tipping sideways. In one embodiment, two tilt prevention arms,  122  and  124 , are positioned at the front and the rear of the support frame  102 , respectively. As illustrated in  FIG. 4 , the tilt prevention arms  122  and  124  are not configured to engage the ground plane  120  when both of the coaxial wheels  108  are on the ground (including the situations when the knee roller  100  leans slightly forward/backward as described above). However, if one of the coaxial wheels  108  is lifted off the ground while the other remains on the ground, the knee roller  100  may be at a tilted position which may not be desirable. The tilt prevention arms  122  and  124  may be configured to establish contact with the ground if the knee roller  100  is tilted sideways beyond an allowed limit, providing support for the knee roller  100  and helping to prevent falling. 
     It is contemplated that protective sleeves may be utilized to cover and protect at least a portion of the tilt prevention arms  122  and  124 . In addition, a replaceable tip (made of plastic, rubber, metal or the like) may be utilized to protect the end of each tilt prevention arm where it may potentially engage with the ground. It is understood that such replaceable tips may be secured to the tilt prevention arms utilizing screws, snap fit mechanisms, friction fit mechanisms or the like. 
     Furthermore, as illustrated in  FIG. 2 , the tilt prevention arm  124  positioned at the rear of the support frame  102  may be configured to accommodate for movements of the user&#39;s ground engaging leg (i.e., the leg that is not placed on the knee support  106 ). For instance, the tilt prevention arm  124  may include a short arm  124 A and a long arm  124 B. The short arm  124 A may be mounted to the side of the support frame  102  where the user&#39;s ground engaging leg is to be located, thus providing more freedom of movements for that leg. The long arm  124 B may be mounted to the support frame  102  on the opposite side. It is contemplated that the short arm  124 A and the long arm  124 B may be configured to be adjustable/interchangeable parts, providing freedom of movements for the user whether the ground engaging leg is the user&#39;s right leg or left leg. 
     It is contemplated that the support frame  102  may be structured in various ways. The support frame  102  in a particular embodiment may include a first (lower) support bar  126  configured for receiving the pair of coaxial wheels  108 . The first support bar  126  may also define a receptacle  130  for receiving the knee support  106  and a receptacle  132  for receiving the handlebar assembly  104 . The auxiliary wheels  116  and  118  may also be mounted to the first support bar  126 . The support frame  102  may also include a second (upper) support bar  128  positioned above and generally parallel to the first support bar  126 . The upper support bar  128  may provide additional structural support for the knee support receptacle  130  and the handlebar assembly receptacle  132 . However, it is understood that such a structural implementation of the support frame  102  is merely exemplary; various other structural implementations may be utilized to form the support frame  102  without departing from the spirit and scope of the present disclosure. 
     It is understood that the present disclosure is not limited to any underlying implementing technology. The present disclosure may be implemented using a variety of technologies without departing from the scope and spirit of the disclosure or without sacrificing all of its material advantages. 
     It is believed that the present disclosure and many of its attendant advantages will be understood by the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of the components thereof without departing from the scope and spirit of the disclosure or without sacrificing all of its material advantages. The form herein before described being merely an explanatory embodiment thereof, it is the intention of the following claims to encompass and include such changes.