Abstract:
A knee brace is provided with push button actuatable stops, wherein the stops are biased outward into angular locking positions and inwardly directed pressure on the push buttons releases the stops and permits angular adjustment of the stops. A pair of catch plates with locking recesses facing inward, are provided, and outwardly biased locking pins engage the recesses in both catch plates. Each of the stop assemblies has an outwardly directed plate extending over the outer cover plate, and this plate is coupled to the physical stop member around the outer edge of the outer cover plate. The cover plate has angular indicia thereon, which may be viewed through windows in the outwardly extending plate portions of the stop assemblies.

Description:
FIELD OF THE INVENTION 
   This invention relates to ergonomic knee braces. 
   BACKGROUND OF THE INVENTION 
   In the field of adjustable knee braces or supports, it is desirable that the brace include arrangements for limiting the movement of the lower leg relative to the upper leg both as to bending the knee or flexion, and as to extension of the lower leg relative to the upper leg. Various knee brace arrangements have been proposed, and these have included upper struts for extending along the thigh, and lower struts for extending along the lower leg or calf. These are normally provided both on the inside or medial side of the leg and also on the outer or lateral side of the leg; and the medial and lateral struts are normally padded, and provided with straps to hold them in place. Pivoting arrangements are provided for coupling the upper and lower struts, and stops are provided for limiting both extension and flexion of the knee. 
   The prior art patents in the field of knee braces include U.S. Pat. No. 5,672,152 granted Sep. 30, 1997; U.S. Pat. No. 5,921,946, granted Jul. 13, 1999; U.S. Pat. No. 4,817,588, granted Apr. 14, 1989, U.S. Pat. No. 4,953,543 granted Sep. 4, 1990, and U.S. Pat. No. 4,620,532 granted Nov. 4, 1986. Although many of the foregoing provided useful results, these prior art knee braces had shortcomings, in that they were unduly bulky, or were not simple to adjust, or did not have as many stop increments as would be desired, or were otherwise not ergonomically configured. 
   INVENTION SUMMARY 
   Accordingly, objects of the invention include providing a knee brace which is compact, easy to use, which has many points of adjustment and is otherwise ergonomically configured. Preferably the adjustments should be simple and natural so that there is no need to resort to collateral written instructions. 
   Initially, relative to an illustrative preferred embodiment of the present knee brace, the knee brace stop construction operates at the periphery of the pivot arrangements so that the number of stop increments is maximized for the size of the pivot discs. Secondly, the stops may be operated by simple inward pressure on a push button associated with the flexion stop or the extension stop, to release the stop, followed by rotation of the stop to virtually any desired angle, and then followed by release of the push button to permit locking of the stop in the new angular position. With this simplified ergonomic construction, the stop adjustments may be easily made while the brace is mounted on the leg; and the mode of accomplishing stop adjustments is substantially self evident, with the shifting of the stops resulting in the natural or expected angular change in flexion or extension stops. 
   In order to achieve the foregoing results in one illustrative embodiment, the pivoting assembly interconnecting the upper and lower struts includes, for both extension and flexion, at least one generally circular or arcuate catch plate with stop recesses facing or opening inward toward the center of the assembly, and a movable stop member pivoted at the center of the assembly and having an outwardly biased locking member for selectively engaging one of the stop recesses, and with the locking member attached to a release button which extends radially outward to the periphery of the pivot assembly. 
   Viewed from a different aspect, the pivoting assembly may include an outer cover or closure plate and an inner cover or closure plate; an arcuately configured array of locking steps; a movable stop member pivoted at the center of the assembly and having an outwardly biased locking member for selectively engaging at least one of the locking steps; and with the locking member attached to a release button which is located radially outward at the periphery of the pivot assembly. 
   Additional features may include the provision of angular indicia on the outer surface of the outer one of said cover or closure plates and the implementation of the movable stop assembly by an outer, radially extending flat support member adjacent the indicia, preferably with a window through which the angular indicia may be seen. Further, the movable stop assembly may extend over the edge of one of said plates into the space between the two cover plates to cooperate with the locking steps. This construction contributes to the relatively thin overall configuration of the pivoting assembly, which may be only about one-half inch or about 1.3 cm thick. Also, to provide adequate strength and compactness, the brace and it components are preferably made of high strength material such as steel, titanium, zinc alloys, or other high strength metals or high strength plastic. 
   It is further noted that, in the preferred design, two catch plates are provided, and each of the stop assemblies includes a pin which seats in corresponding recesses in each of the two catch plates, to provide a balanced locking configuration for resisting forces applied between the struts to limit flexion or extension. The inner and outer cover plates may also have complementary recesses to more positively secure the stops at the selected angular position. 
   Referring back to the overall construction as mentioned above, one strut extends from the knee pivot assembly up the upper leg or thigh, and the other strut extends from the pivot assembly down the lower leg. The pivot stop assembly is mounted on the end of a first one of these struts, and the second strut has stop surfaces on its end adjacent the stop assembly which engage the flexion and extension stops. Further, the catch plates as described above are mounted on opposite sides of this second strut, with the locking member of the movable stop assembly engaging locking steps on both of the two catch plates, so that a balanced positive stopping force is transmitted to the second strut when the stop surfaces on the end of the second strut engage the flexion stop or the extension stop. 
   Additional aspects of the knee brace may include the following: 
   (1) catch plates which have separate sets of notches for the flexion and extension stops, and a mechanical coupling between these two sets of notches; 
   (2) Color coded flexion and extension actuation buttons, with the degree indicia set forth in matching different colors; 
   (3) Apertures or holes in the actuation buttons to permit locking of the buttons against change. 
   Other objects, features and advantages of the invention will become apparent from a consideration of the drawings and from the detailed description. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a knee brace assembly illustrating the principles of the invention; 
       FIG. 2  is a plan view of one of the two knee braces included in the knee brace assembly of  FIG. 1 ; 
       FIG. 3  is a side view of the knee brace of  FIG. 2 ; 
       FIG. 4  is an enlarged plan view of a knee brace pivot and motion limiting assembly, illustrating the principles of the invention; 
       FIG. 5  is an enlarged perspective view of the pivot assembly; 
       FIG. 6  is an exploded view of the knee brace assembly illustrating the principles of the invention; 
       FIG. 7  is an enlarged view of the central pivot and stop assembly of the knee brace of  FIGS. 1-6 , with the front cover removed; 
       FIG. 8  is an exploded view of the two movable stops and their associated adjustment buttons, and indication support members; and 
       FIG. 9 through 12  show various stop adjustment configurations for the knee brace. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   While the specification describes particular embodiments of the present invention, those of ordinary skill can devise variations of the present invention without departing from the inventive concept. 
   Referring more particularly to the drawings,  FIG. 1  shows a leg brace  12  for the knee, including two struts extending up and down the leg from a central pivot assembly  14 . Extending along the upper leg is a strut  16 , and extending down the lower leg from the pivot assembly  14  is a lower strut  18 . These struts are sometimes referenced as femoral struts (as extending along the femur or upper leg bone) and tibial struts (extending along the tibia, or the principal lower leg bone). A pivot assembly on the other side of the knee is also provided with struts extending up and down the leg, but these are not visible in FIG.  1 . 
   To hold the struts in place on the leg are a series of straps  22  on the upper leg, and straps  24  on the lower leg. Suitable padding  26  is provided on the upper leg and the struts are normally secured to the padding  26  by appropriate Velcro® or hook and loop type material. Similar padding  28  underlies the strut  18  and straps  24 . The straps  22  extend through the loops  38  to hold the entire assembly together under active usage conditions. 
   The present invention is directed primarily to the pivot stop assemblies which interconnect the struts. For a post-operative patient, it is desirable to be able to limit the bending of the knee both in the extension direction when the patient is straightening his or her leg, and in the flexion direction where the patient is bending the leg at the knee as far as practical under the circumstances. 
   The showing of  FIG. 1  is of the outside of the left leg. On the inside of the left leg is a similar assembly, to that shown in  FIG. 1 , with two struts and a central pivot assembly. The two units are similar and both are held to the leg by the straps  22  and  24 . Most of the parts are common to the inner and outer assemblies, but with the struts and the cover plates being mirror images of one another. 
   To better understand the operation of the entire assembly, it is useful to refer briefly to the exploded view of FIG.  6 . In operation, the two struts  16  and  18  are pivoted relative to one another about center rivet  56 ; and strut  18  has two stop surfaces  32  and  34 . Adjustable stops are mounted to the hinge pivot assembly  14  on strut  16  and the adjustable stops engage stop surfaces  32  and  34  to limit pivoting of the knee in both the extension and the flexion directions. 
     FIG. 2  of the drawings shows the assembly  12  and the pivot assembly  14  with the straps  22  and  24 , and the padding  26  and  28  removed. Visible in  FIG. 2  are the strap coupling members  36  which are secured to the struts, and the strap receiving openings  38 .  FIG. 3  is a side view of the assembly of FIG.  2 . The central stop mechanism  14  will be described in greater detail hereinbelow. 
   Referring now to  FIGS. 4 and 5  of the drawings, these are plan and perspective views, respectively of the central stop mechanism  14  which interconnects the struts  16  and  18 . 
   Now, considering  FIG. 4  in detail, it includes the extension stop assembly  42  and the flexion stop assembly  44 . Visible on the cover plate  46  are degree indicia which may be read through the openings  48  and  50  on the stop assemblies  42  and  44 , respectively. To change the limits of motion, the push buttons  52  and  54  are depressed and the stop assemblies are rotated to the desired angular settings. Incidentally, the outermost surfaces of push buttons  52  and  54  are preferably knurled, ribbed or textured for non-slip engagement. Alternatively the stops may be coated with a frictional coating. 
   Concerning the angular settings, when the extension stop  42  is at zero degrees (0°), the patient is free to fully extend his lower leg. When the extension stop  42  is set to 90°, the lower leg is restrained from movement beyond 90° relative to the upper leg, so the lower leg cannot be straightened out. 
   Regarding the flexion stop  44 , when it is set to 120° the lower leg may be fully bent toward the upper leg. When the flexion stop is set to “lock”, then the lower leg is fully extended, and is blocked from any bending. If both stops  42  and  44  are set to 60° for example, the knee is held at 60° from fully open, and is restrained from movement in either direction. 
   Incidentally, the support members for the stops are both pivoted about the center  56  of the pivot assembly  14 , with the reference number  56  representing the head of a rivet extending through the assembly. 
   Consideration will now be given to the detailed construction of the pivotal stop mechanism, by reference to the exploded view of FIG.  6 . As mentioned above, one of the two struts  18  has the two stop surfaces  32  and  34  on its end, and is pivoted, with opening  62  receiving rivet  56  which extends through the entire assembly. The flat parts  64  and  66  are spacers and also serve the function of washers in facilitating rotation of the overlying parts. They may be formed of plastic such as nylon. The catch plates  68  and  70  have a series of inwardly opening recesses which receive outwardly biased locking pins as described below. 
   The inner cover plate  72  and the outer cover plate  74  may also be provided with inwardly directed recesses, matching those in the catch plates  68  and  70 . This provides supplemental restraint for the locking pins shown in detail in later figures of the drawings. 
     FIG. 7  is an enlarged view of the central mechanism with one of the cover plates removed. The stop assembly  44  has a locking pin  82  which moves inward with the push button  54  to change settings, but is spring biased outward to engage one of the recesses  84 . Similarly, the locking pin  86  associated with push button  52 , locks the stop  42  by engagement with a selected one of the catch plate recesses  84 . 
     FIG. 8  is an enlarged showing of the physical stop members  92  and  94  which engage the stop surfaces  32  and  34  as shown in FIG.  6 . Two small pairs of coil springs  96  and  98  serve to bias the push buttons  52  and  54 , and the associated locking pins  86  and  82  outward, into engagement with the catch plate  68  (see  FIG. 7 ) and the other catch plate  70  (see FIG.  6 ). 
   Incidentally, the physical stops  92  and  94  may be formed of a high strength zinc alloy referenced as ZA-28, or other high strength material. 
     FIGS. 9 through 12  shows various adjustments of the stops, and the resultant permitted positions of the struts  16  and  18 . More specifically,  FIG. 9  shows the extension stop  42  and the flexion stop  44  in their positions for full range of motion, with the extension stop  42  at 0° and the extension stop  44  at 120° (see FIG.  4 ). In  FIG. 9  the struts (and the leg) are fully extended; while in  FIG. 10 , the struts and the leg are bent to their extreme flexed position, with the two stops in the same positions for both FIG.  9  and FIG.  10 . 
     FIG. 11  is a similar pair of drawings with the extension stop at about 45° and the flexion stop at about 75° in both figures. In  FIG. 11  the struts are extended as far as possible with this setting of stops  42  and  44 ; and in  FIG. 12  the struts (and leg) are bent as far as permitted with this setting of the stops  42  and  44 . 
   An alternative embodiment of the stop mechanism may include a physical stop having a radially extending slot for receiving a locking pin associated with a push button; and a wire spring biasing the push button and locking pin radially outward relative to the stop support members. 
   Concerning another matter, with reference to  FIG. 4  of the drawings, the push buttons  52  and their associated assemblies are preferably color coded to match colored angle indicia. Thus, push button  52  may be colored blue, with the associated degree indicia from “0” to “90” degrees being the same blue color; and push button  54  and associated indicia may be colored green. 
   It may be noted that the push buttons are provided with holes near the outer ends thereof. This permits the physician or technical assistant to thread wire or plastic ties through the openings to discourage re-setting or tampering with the angular settings, as shown at reference numerals  101  and  103  in  FIGS. 11 and 12  of the drawings. Other elements for preventing or restricting actuation of the push buttons, including locking ties, may be employed; and these elements may be separate from or integral with and movable with respect to, the knee brace assembly. 
   It is to be understood that the foregoing detailed description discloses one preferred illustrative embodiment of the invention. Various changes and modifications may be made without departing from the spirit and scope of the invention. Thus, by way of example and not of limitation, instead of having catch plates with locking recesses, a series of outwardly extending rods or protrusions may be provided, with the stop buttons having an outwardly biased fork member for engaging the rods and thereby positioning the stop body or stop plate in the desired angular position. In addition, while the disclosed configuration of the stop supports  44  and  48  is preferred, the stop assemblies may be pivotally mounted within the cover plates as well as, or instead of, extending over the outer surface of the outer cover plate. With regard to another matter, the release push button may be integral with the physical stops. Also, the various parts may be replaced by their mechanical equivalents, such as rivets being replaced by threaded fasteners, or the like. Accordingly, the present invention is not limited to the precise embodiments described in detail hereinabove, and shown in the accompanied drawings.