Abstract:
A multi-segment supportive belt assembly for reducing displacement of one or more orthotic devices on the lower extremities of a user. The supportive belt comprises a first group of segments including a plurality of linking segments linking the supportive belt assembly to the anatomical structure of the user, and a second group of segments including, for each lower extremity, at least one lateral segment connecting adjacent linking segments, the at least one lateral segment being longitudinally aligned with the user&#39;s hips, at least one of the lateral segments being adapted to be connected to the one or more orthotic devices.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefits of U.S. provisional patent application No. 61/454,632 filed on Mar. 21, 2011, which is herein incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    The present disclosure relates to a supportive belt assembly for lower extremity orthotic devices. 
       BACKGROUND 
       [0003]    One of the major functional issues with lower extremity orthotic devices is the physical stability of the device on the user&#39;s leg. During its use, a lower extremity orthotic device such as a knee brace tends to displace itself in various directions away from its main pivotal references, i.e. its respective natural axes of rotation. These displacements significantly reduce the efficiency of the orthotic device and even worse, a misalignment of the device with regard to its natural axes of rotation can lead to acute and chronic injuries. In fact, misalignments arising from the displacement of the device from its original position reduce its capability to adequately stabilize the respective joint-segment body structure and, in the case of a powered orthotic device, its ability to transfer additional biomechanical forces to the body. As a consequence, users often use homemade means to try to roughly secure the positioning of their brace with the goal of minimizing its displacement and optimizing its functionality. 
         [0004]    Manufacturers have tried to improve and upgrade the attachment systems of orthotic devices in order to properly secure their biomechanical positioning. The more recent attachment mechanisms are efficient for a certain period of time and for confined conditions of use. Unfortunately, they lose their efficiency when used for an extended duration and/or when the fitting conditions at the structural interface change for any reasons such as the onset of a certain amount of perspiration. Extreme mobility is also a major factor that provokes such displacements of orthotic devices. 
         [0005]    Accordingly, there is a need for a support mechanism for orthotic devices that eliminates undesired displacements. 
       SUMMARY 
       [0006]    The present disclosure provides a multi-segment supportive belt assembly for reducing displacement of one or more orthotic devices on the lower extremities of a user, comprising:
       a first group of segments, including:   a plurality of linking segments linking the supportive belt assembly to the anatomical structure of the user; and   a second group of segments, including, for each lower extremity:   at least one lateral segment connecting adjacent linking segments, the at least one lateral segment being longitudinally aligned with the user&#39;s hips, at least one of the lateral segments being adapted to be connected to the one or more orthotic devices;
 
wherein the multi-segment belt assembly reduces undesired longitudinal, rotational and shifting displacements of the one or more orthotic devices on the lower extremities of the user.
   The present disclosure also provides a multi-segment supportive belt assembly wherein the first group of segments includes:   a first linking segment located at the user&#39;s waist level transferring part of the load generated by the one or more orthotic devices to the user&#39;s pelvic bone;   a second linking segment located at the user&#39;s gluteal level transferring part of the load generated by the one or more orthotic devices to the user&#39;s gluteal muscles; and   a third linking segment located at the user&#39;s thighs proximal end level transferring part of the load generated by the one or more orthotic devices to the user&#39;s thighs proximal ends.       
 
         [0015]    The present disclosure further provides a multi-segment supportive belt assembly wherein the second group of segments, includes, for each lower extremity:
       a first lateral segment that flexibly connects the first linking segment and the second linking segment; and   a second lateral segment that rigidly connects the second linking segment and the third linking segment, the second lateral segment being adapted to be connected to the one or more orthotic devices.       
 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0018]    Embodiments of the disclosure will be described by way of examples only with reference to the accompanying drawings, in which: 
           [0019]      FIG. 1  is a side view of the supportive belt assembly in accordance with an illustrative embodiment of the present disclosure; 
           [0020]      FIG. 2  is a back view of the supportive belt assembly of  FIG. 1 ; 
           [0021]      FIG. 3  is a perspective view of an orthotic device; 
           [0022]      FIG. 4  is a perspective view of the upper thigh contact area; 
           [0023]      FIG. 5  is a cross-sectional view of a mechanical hip joint; and 
           [0024]      FIG. 6  is a perspective view of the mechanical hip joint. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]    Generally stated, the non-limitative illustrative embodiment of the present disclosure provides a supportive belt assembly for lower extremity orthotic devices that eliminates, or at least greatly reduces, undesired displacements of the orthotic devices. The supportive belt assembly is a multi-segment belt assembly worn by the user at the waist and hip level, to which are attached one or more orthotic devices. Thus attached, the longitudinal and the rotational mobility of the orthotic device is restricted by the capacity of the supportive belt assembly to limit, even eliminate, undesirable shifting. 
         [0026]    The supportive belt assembly enhances the stability of lower extremity orthotic devices on a user and, in the case where the orthotic devices are powered, (i.e. can generate biomechanical efforts at the joints), the quality of the force transfer from the lower extremity orthotic devices to the user&#39;s limbs. 
         [0027]    The design of the supportive belt assembly is based upon the concept of the waist as an anchoring central point. 
         [0028]    Referring to  FIGS. 1 and 2 , the supportive belt assembly  10  comprises six major components separated in two groups: a linking segments group and a lateral segments group. The linking segments group includes a waist belt  12 , a lower-back hips belt (LBHB)  14  and upper thigh contact areas  16 , while the lateral segments group includes, on each side of the body of the user, a flexible lateral segment  22  that links the waist belt  12  and the LBHB  14 , and a rigid lateral segment  24  that links the LBHB  14  and the upper thigh contact areas  16 . 
         [0029]    The components  12 ,  14 ,  16 ,  22  and  24  of the supportive belt assembly  10  are grouped with respect to their function into the assembly. The linking segments group ( 12 ,  14 ,  16 ) gathers together components characterized as supportive elements. Components of this first group are of high importance to deliver the assistive capacities of the orthotic devices to the user. The lateral segments group ( 22 ,  24 ) gathers components used to connect together the first group&#39;s supportive components. 
         [0030]    Each component of the linking segment group ( 12 ,  14 ,  16 ) is a direct connection to the human anatomical structure: the waist belt  12  to the waist level transferring part of the load generated by the orthotic devices to the user&#39;s pelvic bone; the LBHB  14  to the gluteal level transferring part of the load generated by the orthotic devices to the user&#39;s gluteal muscles; and the upper thigh contact areas  16  to the thighs proximal end level transferring part of the load generated by the orthotic devices to the user&#39;s thighs proximal ends (i.e. lower buttocks). As can be seen in  FIG. 1 , the waist belt  12  is worn at the waist level and closed by a frontal buckle  13 . Supportive elements have as primary function of creating a mechanical human-machine interface so as to connect to the mechanical bones and muscles structures as directly as possible. The efficiency of this mechanical human-machine interface to stabilize the orthotic devices  30  and/or to transfer forces to users has a direct impact on orthotic devices assistive capacities. 
         [0031]    Components of the lateral segments group ( 22 ,  24 ) are used to connect together the supportive elements, i.e.  12 ,  14  and  16 . Each flexible lateral segment  22  links the waist belt  12  with the LBHB  14 . The flexible lateral segment  22  is important to unconstrain hip movements of the user. The rigid lateral segments  24  links tips the LBHB  14 , via pivot  23 , to the upper thigh contact areas  16  and tip of the frame of the orthotic device  30 , via pivot  25 . 
         [0032]    The purpose of the supportive belt assembly  10  can be summarized in three points: provide vertical stability, provide torsional stability and force transfer. 
       Vertical Stability 
       [0033]    The conical shape of the human legs (i.e. lower extremities) allows the orthotic device  30  to easily slip downward on the leg under its weight. Referring to  FIG. 3 , the four attachment points  32  of the orthotic device  30  are not sufficient to keep the orthotic device  30  in place in a comfortable manner, neither in movement nor in static position. 
         [0034]    Accordingly, one objective of the supportive belt device  10  is to keep the orthotic device  30  in place, vertically, onto the leg of the user, in order to stabilize the orthotic device  30  and/or to transfer part of the load of the orthotic device  30  to the waist of the user. 
       Torsional Stability 
       [0035]    Muscular surfaces onto which the orthotic device  30  lies are more or less firm, depending on the user and on the type of activity carried out. For powered orthotic devices generating biomechanical efforts at their motorized joints, the efficiency of the forces transferred from the joint mechanisms and the body segments is reduced by the fact that a part of these additional forces are lost into muscular tissues before providing the expected level of assistance. Repeated displacements of the orthotic device  30  on the leg result in the rotation of the orthotic device  30  around the leg of the user, moving inwardly and causing potential skin lesions. 
         [0036]    Accordingly, another objective of the supportive belt assembly  10  is to keep the orthotic device  30  in place in order to prevent it from rotating around the leg of the user. 
         [0037]    Force Transfer 
         [0038]    In addition to being uncomfortable, the compression of soft tissues at the upper thigh contact areas significantly decreases the efficiency of the assistance provided by the orthotic device  30 . Hysteresis introduced by the displacement of the orthotic device  30  on the surface of the leg of the user (i,e, the delay that the additional forces generated by the powered orthotic device take to be effectively transferred to the body segment) is not desirable because it lowers the efficacy of the mobility assistance to the user. 
         [0039]    Accordingly, a further objective of the supportive belt assembly  10  is to keep the orthotic device  30  in place to prevent the contact areas  32  of the orthotic device to be pushed into the soft tissues of the leg of the user. 
         [0040]    Each component of the linking segments group ( 12 ,  14 ,  16 ) and the lateral segments group ( 22 ,  24 ) will now be described further, describing their physical structure, their function as well as how each component contributes to reach the stability and force enhancement objectives described above. 
       Linking Segments Group 
     Waist Belt 
       [0041]    With reference to  FIGS. 1 and 2 , the waist belt  12  in the illustrative embodiment is about 5 cm in width and is closed by a frontal buckle  13  (see 
         [0042]      FIG. 1 ). The inward surface of the waist belt  12  is covered with VelcroTM loops compatible with potential Velcro™ hooks on the pants of the user to limit undesired movements of the waist belt  12 . Tips of the inward surface of the waist belt  12  have Velcro™ hooks which allow an easy adjustment to the waist measurement of the user. The waist belt  12  is made of two thick polypropylene straps sewed together, resulting in a high rigidity cross section, able to resist in vertical planes to torsion efforts applied by the weight of the orthotic device  30 . The waist belt  12  cross section rigidity is required to prevent local deformation of the belt causing considerable discomfort to the user. Each orthotic device  30  is linked to the waist belt  12  by the mean of a flexible lateral segment  22  that connects the waist belt  12  and the LBHB  14 . 
         [0043]    The pelvis bone offers a solid structure for a comfortable and even distribution of orthotic device  30  load. The waist belt  12  transfers part of the load from the orthotic devices  30 , approximate 1.5 kg each, to the waist of the user through its flexible lateral segment  22 . Thus, downward displacement of the orthotic devices  30  is prevented, and vertical stability objective is reached. 
         [0044]    Furthermore, assistance forces can be transferred to the waist of the user, offering an additional point of contact between the orthotic devices  30  and the user and improving the efficacy of force transfer. 
       Lower Back-Hips Belt (LBHB) 
       [0045]    With reference to  FIGS. 1 and 2 , the role of the LBHB  14  is to provide the rigid lateral segment  24  a fixed position where to be attached at the waist. Since free rotations in the sagittal plane are required for all hips&#39; movements, the LBHB  14  is connected to the frame of the orthotic device  30  via pivots  23  and  25  of the rigid lateral segment  24 . This mechanical parts assembly lets the hips&#39; joints free to move while providing a firm attachment to the user&#39;s waist. 
         [0046]    The LBHB  14  in the illustrative embodiment is made of a strong and thick polypropylene weaving of about  5  cm in width that can resist substantial torsion efforts. It has to be flexible to conform to the lower back shape during assisting phases so as to offer a surface of contact as large as possible; the largest the surface of contact the more evenly is the load distributed on the user&#39;s waist, resulting in a direct comfort improvement. Fitting holes are provided on each side, accommodating various waist sizes. For example, the LBHB  14  can be provided with eight fitting holes accommodating waist sizes from about 71 cm to 101 cm. Pivots  23  and  25  are attached to the LBHB  14  and the frame of the orthotic device  30  through these holes by mean of a mechanical bolt and nut pivot, or any other such attachment. 
         [0047]    The purpose of the LBHL  14  is to keep in place the upper ends of the orthotic devices  30  and to offer a force transfer contact area independent of the waist belt  12 . 
         [0048]    It can be observed that the LBHL  14  has no forward section. The purpose of the absence of a forward section is to eliminate antero-posterior constraints on pivot  23 . Pivot  23  is advantageously located above and a little behind the natural hip joint; in which case, a lever of force is created above the mechanical pivot point. For all forward legs movements (crouching, sitting, large forward strides, etc.), this lever of force may cause a frontal section to press into the lower abdomen, and thus be an important source of discomfort for the user. For that reason, the LBHB  14  only possesses a rear section. This also explains why the waist belt  12  is minimally connected to the LBHB  14 . The use of a flexible lateral segment  22  in-between the waist belt  12  and the LBHL  14  offers a force transfer contact area independent of the waist belt  12 , and guarantees that no over straining efforts are put on the lower abdomen. 
         [0049]    The attachment point between the LBHB  14  and the upper end of the orthotic device  30  via pivot  25  is located as near as possible to the natural hip joint in the vertical axis. In the horizontal plane, this point is specifically located at the front or a little behind the natural hip joint. It is essential for stability purposes that the point of attachment does not overpass the natural hip joint. During the assisting phases, the LBHB  14  is pressed on the lower back of the user and the position of the attachment point prevents the upper end of the orthotic device  30  from moving forward. Preventing forward displacement as well as displacement around the leg result in a direct stability increase (i.e. torsional stability). 
         [0050]    Also, since the LBHB  14  is being pressed onto the firm lower back and pelvis bone structures, less hysteresis is observed during the first few moments of assisting phases. The quality of force transfer is thus significantly improved. 
       Upper Thigh Contact Areas 
       [0051]    With reference to  FIGS. 1 ,  2  and  4 , the upper thigh contact areas  16  allow the transfer of forces from the orthotic device  30  to the proximal end of the user&#39;s thighs. In the illustrative embodiment, the upper thigh contact areas  16  are made of urethane reinforced with a carbon fiber mattress and have rounded shape in order to provide a high level of comfort to the user. A polypropylene VelcroTM restraining strap  42  surrounds the leg. The doubled sided VelcroTM is used as closing system  44  to lock the upper thigh contact areas  16  onto each leg. The tips  66  of the upper thigh contact areas  16  each include a groove in order to attach the restraining strap. Neoprene cushions  68  are implemented onto the straps to improve user comfort. The “stickiness” characteristic of neoprene material strengthens the resistance to torsion forces in the transversal plane. 
         [0052]    In order to provide a better fit for different user morphologies, each upper thigh contact area  16  is fully adjustable in the sagittal plane: two degree of freedom in translation which can be locked into place, and one degree in rotation, kept free at all time. The vertical translation is possible by means of multiple holes made in the upper brace segment; allowing adjustments for different user heights. The antero-posterior translation allows fitting to the user&#39;s segment diameter by means of a groove made in the backward tip of the upper thigh contact areas  16 . The rotation in the sagittal plane is left free to leave user&#39;s leg free to move while improving the user&#39;s comfort. 
         [0053]    The upper thigh contact areas  16  are specifically located at the buttocks and hamstring muscles junction. This anatomical area is quite close to the pelvic bone structure and consequently reduces compression of soft tissues and undesired orthotic device  30  displacement. The efficacy of force transfer by orthotic devices  30  is then improved, as well as the general user comfort. 
         [0054]    The positioning of the upper thigh contact areas  16  also serves as an anchoring point for the other components of the supportive belt assembly  10 , improving the fit onto the user&#39;s waist and enhancing the general stability of the orthotic devices  30 . 
       Lateral Segments Group 
     Flexible Lateral Segment 
       [0055]    With reference to  FIGS. 1 and 2 , the flexible lateral segment  22  in the illustrative embodiment takes the form of a polypropylene band of a width of about 2.5 cm, linking the waist belt  12  to the LBHB  14  above pivot  23 . 
         [0056]    The main objective of the flexible lateral segment  22  is to transfer the load from the orthotic device  30  to the waist belt  12 ; the flexible lateral segment  22  is actually used to accomplish the load transfer function from the orthotic device  30  when it is put under tension. 
         [0057]    Torso lateral movements have to be comfortable and free of constraints above the human hip joint. Accordingly, the flexibility characteristic of the flexible lateral segment  22  avoids the undesired situation of having a rigid lateral segment above the human hip joint pushed into torso flesh during transversal plane torso rotations. 
       Rigid Lateral Segment 
       [0058]    With reference to  FIGS. 1 and 2 , the rigid lateral segment  24  in the illustrative embodiment takes the form of a 6061-T6 aluminum strip of a width of about 3.8 cm. The rigid lateral segment  24  links pivot  23  to the proximal upper end of the frame of the orthotic device  30  by means of bolts or other such attachment. The function of the rigid lateral segment  24  is to link pivots  23  and  25  of the upper thigh contact areas  16 . Both supportive elements, the LBHB  14  (positioned through pivot  23 ) and the upper thigh contact areas  16  (positioned through pivot  25 ) serve as anchoring elements for the orthotic device  30  in order to transfer assisting force to the user. The positioning of pivot  23  on the transversal plane prevents the orthotic device  30  from moving around the user&#39;s limbs during assisting phases. 
         [0059]    The rigid lateral segment  24  is provided with holes allowing for length adjustments, which as a result positions pivots  23  and  25  of the upper thigh contact areas  16 . The closer pivot  23  is to the actual human hip joint, the more efficient and comfortable will be the supportive belt assembly  10 . 
         [0060]    Deficiencies in stability and force transfer are noticeably reduced using the supportive belt assembly  10 , and the biomechanical benefits directly result in a gain in comfort for the user. Components making up the supportive belt assembly  10  thus provide orthotic devices  30  with a firm and solid anchoring point, allowing the user to get the most out of each orthotic device&#39;s  30  assisting capabilities. 
       Mechanical Hip Joint (MHJ) 
       [0061]    With reference to  FIGS. 5 and 6 , there is shown an illustrative embodiment of a mechanical hip joint (MHJ)  23 ′ that may be used in replacement of pivot  23  (see  FIGS. 1 and 2 ) in an alternative embodiment of the supportive belt assembly  10  or used with other orthotic or robotic devices. The MHJ  23 ′ consist in a ball joint like mechanism having as a primary function the unconstraining of the pelvis and hips movements. The ball joint like mechanism is composed of five main components: an anodized aluminum sphere  52  with and elongated member portion  55 , a two piece ( 54   a  and  54   b ) capsule  54 , a reduced cross section ball bearing  56 , an optional angular position sensor  58  and a housing  59 . The housing  59  is attached to the LBHB  14 , the capsule 54  being rotatably connected to the housing  59  via the reduced cross section ball bearing  56 . The sphere  52  is positioned inside the capsule  54  and its elongated member portion  55  forms the rigid lateral segment  24 , protruding from the capsule  54  through groove  53 . 
         [0062]    The human hip can execute movements with respect to the three rotational axes. Leaving the user&#39;s movements unconstrained requires the MHJ  23 ′ to mimic the three decoupled natural hip rotations. Referring to  FIG. 6 , the vertical rotation (Z-transverse plane) is allowed by the sphere  52 , rotating vertically inside its capsule  54 . The frontal rotation (Y-transverse plane) is made possible through a groove  53  made perpendicularly with respect to the sagittal plane. The MHJ  23 ′ allows the user to move its legs sideward, i.e. sagittal rotation (X-transverse plane), from an angle of about  90  degrees in abduction to an angle of about  10  degrees in adduction. It is the groove  53  that decouples the frontal rotation axis (Y-transverse plane) from the sagittal rotation axis (X-transverse plane). The groove  53  prevents the sphere  52  from rotating inside its capsule  54  during sagittal axis rotations. It is then the capsule  54  itself that rotates, through the action of the ball bearing  56 , with respect to the housing  59 . This third rotation can be monitored with an optional sensor, for example a magnetic angular position sensor, for artificial intelligence purposes. 
         [0063]    All degrees of adjustment and degrees of freedom are addressed: circumferential localization of MHJ  23 ′ on the waist is possible; abduction and adduction movements are not restrained; and the three natural rotations are let free and decoupled. The MHJ  23 ′ is then used as a link between the LBHB  14  and the upper end of orthotic devices  30  to leave unconstrained natural pelvis&#39; and hips&#39; movements. The unconstraining action of this mechanism allows the LBHB  14  and orthotic devices  30  to stay fixed onto user&#39;s waist and legs, resulting in a major stability improvement. 
         [0064]    The MHJ  23 ′ also links the orthotic device  30  to the waist belt  12 , allowing the load to be properly distributed to the waist belt  12  without over constraining pelvis&#39; and hips&#39; movements. 
         [0065]    It is to be understood that the various components of the supportive belt assembly  10  have been described in accordance with illustrative embodiments of the present disclosure and that the material used, as well as their dimensions, may vary depending, for example, on the application and/or the size of the user. 
         [0066]    Although the present disclosure has been described by way of particular non-limiting illustrative embodiments and examples thereof, it should be noted that it will be apparent to persons skilled in the art that modifications may be applied to the present particular embodiment without departing from the scope of the present disclosure.