Patent Publication Number: US-2019167461-A1

Title: Articulated rod of an orthopaedic device

Description:
TECHNICAL FIELD 
     The present disclosure refers to an articulated rod of an orthopedic device. 
     BACKGROUND 
     In the state of the art there are articulated rods of orthopedic devices with polycentric joints and removable inserts for constraining a flexion-extension rotation within a certain width. It is necessary to use inserts of different shapes and sizes to constrain different rotation widths. Disadvantageously, whenever the rotation width is to be changed, it is necessary to dismount the inserts from the joint and replace them with others making the adjustment operation complicated as it is connected with mounting and dismounting the inserts. 
     Inserts exist that are removable in an orthogonal direction to a rotation plane of arms that constrain the rotation within a slot, but disadvantageously they constrain the movement of both arms together, making it difficult and impractical to adjust the rotation width of the articulated rod. 
     BRIEF SUMMARY 
     The disclosure provides an articulated rod with an easily adjustable flexion-extension rotation, which is secure, compact and small. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The characteristics and advantages of an articulated rod with a polycentric joint that can be adjusted in extension-flexion according to the present disclosure will be more apparent from the following description, which is to be understood as exemplifying and not limiting, with reference to the schematic attached drawings, wherein: 
         FIG. 1  shows an exploded perspective view of the articulated rod with a polycentric joint, arms with through holes and slots, cams, toothed button, stop buttons and cover; 
         FIG. 2  shows a section of the articulated rod with the polycentric joint with arms hinged with the cams; 
         FIG. 3  shows a view of a cam from the outside; 
         FIG. 4  shows a view of the cam from the inside; 
         FIG. 5  shows a view of the toothed button from the outside; 
         FIG. 6  shows a view of the toothed button from the inside; 
         FIG. 7  shows a view of a stop button from the outside; 
         FIG. 8  shows a view of the stop button from the inside; 
         FIG. 9  shows a view of the cover from the outside; 
         FIG. 10  shows a view of the cover from the inside; 
         FIG. 11  shows a view from the outside of the articulated rod with the stop buttons disengaged from the cover and from the toothed button which is in turn disengaged from the cams that are free to rotate on rotation pins; 
         FIG. 12  shows a dismounted detail of the articulated rod with the stop buttons in the disengaged position; 
         FIG. 13  shows a perspective view of  FIG. 12 ; 
         FIG. 14  shows a dismounted detail of the articulated rod with the stop buttons in the engaged position with the cover, with the toothed button, which is in turn engaged with the cams, blocking the movement thereof; 
         FIG. 15  shows a perspective view of  FIG. 14 . 
     
    
    
     DETAILED DESCRIPTION 
     With particular reference to  FIGS. 1 and 2 , an articulated rod  10  of an orthopedic device is shown comprising a pair of arms  20 , two cover plates  30  and a polycentric joint  40  that is mounted with the two cover plates  30  and that articulates the pair of arms  20 . 
     The articulated rod  10  further comprises two cams  50 , a toothed button  60 , two stop buttons  70  and a cover  80 . 
     The two cover plates  30  are an outer cover plate  31  and an inner cover plate  32 , where the terms outer and inner refer to mounting directions with respect to the orthopedic device. 
     In general the polycentric joint  40  is defined overall by the means that allows the two arms  20  to mesh with the two plates  30 . The polycentric joint  40  allows a mutual rotation of the pair of arms  20 . The rotation comprises two rotation directions which are a direction of flexion rotation and a direction of extension rotation. The rotation takes place on a geometric plane of rotation. 
     Each arm  20  bears a first end  21  that can be associated with the orthopedic device and a toothed end  24  opposite the first end  21 . 
     The toothed ends  24  of the pair of arms  20  are meshed together for performing the rotation. Each toothed end  24  bears a central hole  25  in the axial position with respect to the extension of the toothed profile. 
     The two cover plates  30  are coupled to each other to form a shell and house the two toothed ends  24  and two rotation pins  42  of the articulated rod  10 . The two rotation pins  42  are arranged orthogonally with respect to said geometric plane of rotation and are engaged in respective central holes  25  of the toothed ends  24  and define an axial direction. 
     The inner cover plate  32  bears two through holes  34  in which each of the two rotation pins  42  is engaged respectively. 
     The outer cover plate  31  bears two through openings  35  in which the cams  50  are rotatably engaged. 
     Each cam  50  bears a through hole  55  in which the rotation pin  42  is engaged. 
     Each toothed end  24  bears a slot  29  that is engaged by an axial extension  59  of cam  50 . In the example shown in the figures and in particular in  FIG. 2 , the slot  29  is in communication with the through opening  35  of the outer cover plate  31 . The slot  29  of the arm  20  has a first end stop wall  27  and a second end stop wall  28 , that constrain the movement of the respective axial extension  59  of the cam  50 . 
     As shown in particular in  FIG. 2 , the two slots  29  have a central symmetry with respect to a geometric center arranged between the two arms  20  that lies on the geometric plane of rotation. This means that observing  FIG. 2 , the left arm  20  shows that the first end stop wall  27  is at the bottom with respect to  FIG. 2 , the second end stop wall  28  is at the top with respect to  FIG. 2 , while for central symmetry, the arm  20  on the right shows that the first end stop wall  27  is at the top with respect to  FIG. 2  and the second end stop wall  28  is at the bottom with respect to  FIG. 2 . 
     As shown in particular in  FIGS. 3 and 4  each of the two cams  50  is disc-shaped, where the perforated center of the disc is the through hole  55 . For each cam  50  two distinct perimeter geometric profiles can be identified, respectively an outer portion and an inner portion overlapping one another on the geometric plane of rotation and preferably realized as a single piece. 
     On the geometric plane of rotation it is envisaged that a perimeter segment of the outer portion of the cam  50 , extended at about an angular sector of 180°, has a plurality of radial extensions that are coupling teeth  56 . A second perimeter segment of the outer portion of the cam  50 , diametrically opposite the first perimeter segment, has a radial extension  53 . As shown in the embodiment of  FIGS. 1-2, 11-15 , it is envisaged that the radial extension  53  of the cam  50  is in two pieces that can be separately mounted with each other. The radial extension  53  of the cam  50  comprises an indication slider  54  that extends in the axial direction and a selector tooth  51  that extends from the wall of the radial extension  53  of the cam  50 . The indication slider  54  is a lever adapted to be managed by the orthopedist. 
     As shown in particular in  FIGS. 1-4 and 12-15 , the inner portion of the cam  50  has a hollow axial extension  52  that identifies the through hole  55  of the cam  50 , comprising a succession of discs that extend axially from the outer portion of the cam  50 . The succession of discs of the hollow axial extension  52  comprises an outer disc adapted to be rotatably engaged with the through opening  35  of the outer cover plate  31  and an inner disc adapted to be rotatably engaged with the through hole  25  of the arm  20 , inner and outer meaning the mounting directions of the articulated rod  10  with the orthopedic device. 
     The axial extension  59  engaged in the slot  29  is a single piece with the hollow axial extension  52  of the cam  50 . The axial extension  59  of the cam  50  comprises a first stop wall  57  adapted to go into abutment with the first end stop wall  27  of the slot  29  of the arm  20  and a second stop wall  58  adapted to go into abutment with the second stop wall  28  of the slot  29  of the arm  20 . In the example described in the figures the axial extension  59  of the cam  50  has a section in the rotation plane in the form of a circular crown for advantageously making the cam  50  and its connection to the slot  29  of the arm  20  more solid. 
     As shown in particular in  FIGS. 5-6 , the toothed button  60  comprises two side walls  63 ,  64  that each comprise a respective plurality of teeth  65  adapted to be engaged by at least one tooth  56  of the pair of cams  50 , as shown in  FIGS. 1 and 2 . The side wall  63 ,  64  and the teeth  65  of the toothed button  60  have a complementary shape with respect to the toothed perimeter segment of the cam  50  and the respective teeth  56  of the cam  50  for being engaged together. A first side wall  63  of the toothed button  60  is directed in the direction of the plurality of teeth  56  of a first cam  50  of the two cams  50 . A second side wall  64  of the toothed button  60  is directed in the direction of the plurality of teeth  56  of a second cam  50  of the two cams  50 . 
     The button  60  is mounted with the outer cover plate  31  by means of two elastic elements  90  of the articulated rod  10  so as to be able to pass from an engagement position to a disengagement position with the cams  50 . 
     In the embodiment shown in the figures, the elastic element  90  is a helical spring. The elastic element  90  passes from a work position where the helical spring  90  is compressed to a relaxed position where the helical spring  90  is elongated. The toothed button  60  has an outer face  61  and an inner face  62 . The inner face  62  bears two seats  69  each adapted to house a respective end of the elastic element  90 . The other end of the elastic element  90  is housed in a respective seat  39  of an outer face of the outer cover plate  32 . 
     The outer face  61  of the toothed button  60  has a raised part  68  that is adapted to pass through a through opening  86  of the cover  80 , as shown in  FIG. 11 . 
     The engagement position of the toothed button  60  envisages that the elastic element is in the work position, that at least one part of the plurality of teeth  65  of the first side wall  63  of the toothed button  60  is engaged with at least one part of the plurality of teeth  56  of the first cam  50  and that at least one part of the plurality of teeth  65  of the second side wall  64  of the toothed button  60  is engaged with at least one part of the plurality of teeth  56  of the second cam  50 . 
     The disengagement position of the toothed button  60  envisages that the elastic element  90  is in the elongated position, that not even one tooth  65  of the two side walls  63 ,  64  of the toothed button  60  is engaged with some of the teeth  56  of the two cams  50 . 
     The plurality of teeth  56  of the cams  50  and the plurality of teeth  65  of the toothed button  60  advantageously allows the position of each cam  50  to be individually adjusted in the slot  29  of the arm  20 , further allowing an end adjustment of the flexion-extension rotation width of the articulated rod  10  through a plurality of discrete angular positions. 
     The toothed button  60  also envisages two side walls  66  facing in the orthogonal direction with respect to the direction in which the two side walls  63  and  64  are facing. Each side wall  66  comprises two fins  67  that extend in a parallel plane to the rotation plane. Each fin  67  is adapted to be engaged by a stop element  76  of the stop button  70 . 
     In the disengagement position the toothed button  60  has the fins  67  in abutment against an inner face of the cover  80  and the raised part  68  entering into the through opening  86  of the cover  80 . 
     Advantageously the raised part  68  of the toothed button  60  engaged with the through opening  86  of the cover  80  allows the movement of the toothed button  60  to be guided more safely, at the same time facilitating the locking, unlocking and adjustment operations of the constraints to the flexion-extension rotation width of the articulated rod  10 . 
     As shown in particular in  FIGS. 7-8 , the two stop buttons  70  are engaged with the cover  80  and are adapted to pass from a locking position to an unlocking position with the toothed button  60 . 
     Each stop button  70  comprises a bridge  73  from which two extensions  71  project in the direction of the fins  67  of the toothed button  60 . Each extension  71  envisages a seat  76  adapted to come into engagement with the respective fin  67  of the toothed button  60  for locking the toothed button  60  in the engagement position. 
     The seat  76  of the stop button  70  for the fin  67  of the toothed button  60  is provided on an inner face of the stop button  70 . 
     The extension  71  comprises an end stop engagement  78  that is adapted to engage with a stroke end stop  87  of the cover  80  when the stop button  70  is in the unlocking position. 
     The outer face of the extension  71  bears the end stop engagement  78 . 
     The extension  71  is sufficiently long to provide for the sliding of the stop button  70  from the locking position to the unlocking position. 
     The stop button  70  also envisages two elastic fastening elements  72  adapted to be engaged with respective seats  82  of the cover  80 , so that in the locking position the two elastic fastening elements  72  are engaged in the seats  82  of the cover  80 . 
     The stop button  70  further comprises a gripping raised part  74  that extends towards the outside. 
     As shown in  FIGS. 14-15 , the locking position of the stop button  70  envisages that the two fastening elements  72  of the stop button  70  are engaged in the respective seats  82  of the cover  80 , stop elements  76  of the stop button  70  are engaged above respective fins  67  of the toothed button  60  so that the toothed button  60  remains in the engagement position. 
     As shown in  FIGS. 11-13 , the unlocking position of the stop button  70  envisages that the fastening elements  72  of the stop button  70  are disengaged from the respective seats  82  of the cover  80 , stop elements  76  of the stop button  70  are not engaged with the fins  67  of the toothed button  60  so that the toothed button  60  remains in the disengagement position. 
     As shown in  FIGS. 9-10 , the cover  80  comprises four seats  82  for the respective four elastic fastening elements  72  of the stop button  70 , two semi-circular slots  85  adapted to allow the passage of the indication slider  54  of the cam  50 , the through opening  86  adapted to allow the passage of the raised part  68  of the toothed button  60 , two through holes  88  adapted to engage two closing pins  48  that engage the cover  80  with the cover plate  30  by means of respective through holes  38  of the cover plate  30 . 
     Each slot  85  of the cover  80  carries a plurality of seats  81  adapted to allow the engagement of the selecting tooth  51  of the cam  50 . 
     The cover  80  bears a graduated scale, which is not shown in the figures, adapted to allow each position of the selecting tooth  51  in a seat  81  of the plurality of seats  81  of the cover  80  to match with a defined rotation width. 
     An inner face of the cover  80  comprises raised parts that are stroke end stops  87  adapted to stop the sliding of the extension  71  of the stop button  70  during the passage from the locking position to the unlocking position engaging the respective end stop engagements  78  of the stop button  70 . 
     The cover  80  also envisages guide elements  89  adapted to allow the guided sliding of the extensions  71  of the stop button  70  while it passes from the locking position to the unlocking position. 
     In relation to the adjustment of the articulated rod  10 , with particular reference to  FIGS. 11-15  and starting from the unlocking position of the stop buttons  70 , the orthopedist constrains the flexion-extension rotation width by handling the two indication sliders  54  of the cams  50  that exit from the two slots  85  of the cover  80 . In the unlocking position of the stop buttons  70  it is possible to independently adjust each cam  50  making it rotate by moving the indication slider  54  inside the slot  85  of the cover. 
     The cam  50  can rotate and is constrained by the abutment of the stop walls  57 ,  58  of the axial extension  59  of the cam  50  against the respective stop walls  27 ,  28  of the through slot  29  of the arm  20 . 
     Once the position of the cams  50  has been chosen, the toothed button  60  is pressed from the outside towards the inside so that at least a part of the teeth  65  of the toothed button  60  are engaged with a respective plurality of teeth  56  of the cam  50 , making the toothed button pass from the disengagement position to the engagement position. 
     After this step the stop buttons  70  are made to slide by the orthopedist inside the cover  80  handling the gripping raised parts  74  of the stop button  70  and making the stop buttons  70  pass from the unlocking position to the locking position in which the stop elements  76  of the stop buttons  70  are positioned above the fins  67  of the toothed button  60  so as to lock the toothed button  60  in the engagement position, preventing the elastic elements  90  from passing to the elongated position. The elastic fastening elements  72  of the stop button  70  are engaged in the respective seats  82  of the cover  80  preventing the stop buttons  70  from passing to the unlocking position by mistake. 
     In relation to the operation of the articulated rod  10  after the orthopedist has adjusted the position of the cams  50 , the toothed button  60  is engaged with the two cams  50  and the stop button  70  is in the locking position, according to the preferred embodiment as shown in particular in  FIG. 2 , each of the two cams  50  blocks the flexion and the other one the extension, respectively. 
     In relation to the extension rotation width, this is blocked by the stop wall  27  of the slot  29  that only abuts against the stop wall  57  of the first cam  50  and the two toothed ends  24  of the arms  20  are in abutment with each other. 
     In relation to the flexion rotation width, this is blocked by the stop wall  27  of the slot  29  that only abuts against the stop wall  57  of the second cam  50  and the two toothed ends  24  of the arms  20  are in abutment with each other. First cam  50  means the one shown on the left in  FIG. 2 , whereas second cam  50  means the one shown on the right in  FIG. 2 . 
     Advantageously, the articulated rod  10  of the present disclosure can be easily adjusted in flexion-extension, allowing each cam  50  to be adjusted independently, which is compact and small and is a lot safer. 
     Advantageously only one cam  50  and the block between the two toothed ends  24  constrains the flexion or extension rotation width. Advantageously there are no removable parts, hence making the adjustment of the articulated rod  10  safer and easier. 
     Alternatively, the slot  29  is separate from the through opening  35  and the cam  50  envisages the hollow axial extension  52  not being a single piece with the axial extension  59  adapted to be engaged in the slot  29  of the arm  20 . 
     Also alternatively it is possible to envisage that the first stop wall  57  and the second stop wall  58  are not a single piece, i.e. that each cam  50  comprises two axial extensions  59 , a first axial extension comprising the first stop wall  57  adapted to abut with the first end stop wall  27  of the slot  29  of the arm  20  and a second axial extension comprising the second stop wall  58  adapted to abut with the second stop wall  28  of the slot  29  of the arm  20 . 
     A further alternative envisages that the radial extension  53  of the cam  50  is realized in a single piece with the cam  50 . 
     Another alternative envisages that the toothed button  60  engages directly with engagement elements of the cover  80  without the need for stop buttons  70 . 
     An alternative envisages that the stop buttons comprise engagement teeth with respective teeth  56  of the cams  50  so as to lock the position of the cams  50  in the locking position of the stop buttons. 
     More generally it is envisaged as an alternative that at least one locking element  60 ,  70  comprises a plurality of teeth that engage with the plurality of teeth  56  of the pair of cams  50  for constraining the rotation width of the articulated rod  10 . 
     Also alternatively it is envisaged that the two slots  29  of the two arms  20  may not be arranged according to the central symmetry with respect to the geometric center lying on the geometric plane of rotation. In said yet another alternative it is envisaged that different walls  57 ,  58  of the axial extension  59  can abut with the respective end stop walls  27 ,  28  of the slots  29 . 
     Alternatively the indication slider  54  may be any other indication element adapted to determine the rotation position of the cam  50  with respect to the slot  29 . 
     The articulated rod  10  according to the disclosure can be applied indifferently to orthopedic devices for the upper or lower limbs. 
     The articulated rod thus conceived is susceptible to many modifications and variations, all falling within the disclosure; furthermore, all the details are replaceable by technically equivalent elements. In practice, the materials used, as well as the dimensions, can be any according to the technical requirements.