Abstract:
An ankle-foot orthotic which permits plantarflexion and dorsiflexion while restricting inversion and eversion of the ankle. The orthotic includes a lower leg shell attachable to the lower leg of the wearer inside of the wearers trousers, a foot shell held in place inside the wearer&#39;s shoe, by the shoe itself, and a pair of mechanical joints attaching the lower leg shell to the foot shell. The mechanical joints are pivotally attached to the foot shell allowing rotation on an axis through the ankle joint, but are rigid perpendicular to the axis of the ankle joint thereby restricting sideways bending movement of the ankle. The mechanical joints have internal springs which allow translational movement of the lower leg shell relative to the foot shell providing greater comfort to the wearer by reducing rubbing and chafing of the user&#39;s leg while creating extra cushioning and shock absorption.

Description:
BACKGROUND 
     The invention relates to orthotic braces and more particularly to pivotal leg and foot orthotics designed to permit plantarflexion and dorsiflexion while at the same time restricting inversion and eversion of the foot. 
     Due to the growth in popularity of sports participation there has been a subsequent growth in sports injuries, among them are ankle sprains and strains caused by excessive inversion or eversion of the foot. Those who suffer from such ankle injuries need an ankle brace which will allow them to rehabilitate the ankle by restricting the turning in and turning out, known as inversion and eversion, of the ankle but will allow free movement up and down of the ankle, known as dorsiflexion and plantarflexion. Such a brace needs to allow a user to continue walking or continue participating in athletic activity, if desired, and offer someone with weak ankles extra support. In short, a brace is needed which permits rotational movement through the axis of the ankle joint while restricting sideways bending movement perpendicular to the axis of the ankle joint. Such brace should also provide shock absorption and be comfortable, lightweight, unobtrusive, simple and inexpensive. 
     In the past such purposes have been achieved through the use of plastic or cloth foot and ankle members connected with a pivot joint, which allow rotational movement and restrict lateral movement but have little in the way of shock absorption and could allow rubbing and chafing of the lower leg if the leg is not properly wrapped. Such braces are often only wearable outside of the shoe and trousers, or cannot be worn with shoes or normal trousers at all, causing embarrassment and inconvenience to the wearer. 
     Additional braces allow for greater shock absorption and comfort, but in doing so, have complicated mechanisms joining foot and ankle members that are intricate, bulky and can be binding. Such braces are worn outside of the shoe and trousers or cannot be worn at all with shoes and trousers, again leading to embarrassment and inconvenience as the braces mentioned previously. Increased comfort has been achieved through greater flexibility laterally at the ankle joint, but this is not desirable when inversion and eversion are to be restricted. The joining mechanisms, being complicated, are more difficult to manufacture and therefore more expensive and more difficult to maintain. 
     Other braces attach directly to the wearer&#39;s shoe. These are not concealable, could damage the shoe they are affixed to and depend for strength, in part, on the shoe itself. The jointing mechanisms are also delicate, binding and pinching to material near the jointing mechanism. 
     Postoperative and post-injury braces are available which restrict inversion and eversion. These braces can have adjustments to allow some rotation of the ankle joint, but rotation is limited to a degree if not restricted altogether. Such braces are very bulky, heavy, unsightly and will allow only restricted plantarflexion and dorsiflexion of the foot. Such braces are not particularly designed for the purposes outlined above. 
     There is, thus a need for an ankle foot orthotic that is lightweight, strong, wearable inside of the shoe and trousers, simple to construct, use and maintain, comfortable and economical while at the same time permitting dorsiflexion and plantarflexion, restricting inversion and eversion of the foot and also providing a means of shock absorbency for the further comfort of an injured or healthy wearer participating in athletic activity, walking or rehabilitating. 
     SUMMARY 
     The present invention is directed to an ankle-foot orthotic that is lightweight, strong, wearable inside of the shoe and trousers, simple to construct, use and maintain, comfortable and economical while at the same time permitting dorsiflexion and plantarflexion, restricting inversion and eversion of the foot and also providing a means of shock absorbency for the further comfort of an injured or healthy wearer participating in athletic activity, walking or rehabilitating. 
     An ankle-foot orthotic having features of the present invention comprises a foot shell and a lower leg shell. The foot shell is pivotally attached to the lower leg shell employing a hinging means which permits rotational and translational movement of the foot shell relative to the lower leg shell. The hinging means also restricts sideways bending movement of the foot shell relative to the lower leg shell. The permitting of rotational movement allows desired dorsiflexion and plantarflexion of the foot to occur. Permitting translational movement allows up and down movement of the lower leg brace relative to the foot brace and provides shock absorbency to the orthotic and comfort for the wearer. The restriction of sideways movement prevents undesirable and injury causing excessive inversion and eversion of the foot. 
     The hinging means comprises a lateral mechanical joint located at the outside of the wearer&#39;s ankle and a medial mechanical joint located at the inside of the wearer&#39;s ankle. Each mechanical joint comprises a housing, a slider, a cover, a spring means and a pivoting means. The housing is hollow with an open face and a partially open end. The slider is positioned freely inside of the hollow cavity of the housing and is shaped to project through the partially open end of the housing but shaped not to be removable through the partially open end. A cover is affixed over the open face of the housing that in one embodiment of the invention is secured to the housing with screws. With the cover in place, the slider is rigidly held inside of the housing, thereby allowing only restricted side to side movement of the hinging means perpendicular to the ankle joint. Spring means are positioned inside of the housing which provide cushioning during translational movement of the slider, and the ankle-foot orthotic as well, while also allowing the slider and ankle-foot orthotic to return to a neutral position when neither upward or downward forces are being applied to the wearer&#39;s foot or leg. A pivoting means is attached to the end of the slider projecting through the partially open end of the housing thereby providing rotational movement to the ankle-foot orthotic. 
     The foot shell of the present invention is made of a plastic material that is molded in a thin layer to a wearer&#39;s foot so that the foot, with foot shell attached, can easily fit within the wearer&#39;s shoe. The foot shell comprises a lower plate on which the sole of the foot rests, an upright lateral sidewall adjacent to the outside of the foot and extending upward to the axis of the ankle joint where it flares away from the ankle to accept the fitting of the pivoting means, an upright medial sidewall adjacent to the inside of the foot and also extending upward to the axis of the ankle joint where it flares away from the ankle to accept the fitting of the pivoting means, and a rounded posterior wall in which the heel of the wearer is enclosed. The lower leg shell is likewise made of a plastic that is molded in a thin layer to a wearer&#39;s lower leg from slightly above the ankle joint to below the knee so that the lower leg, with leg shell attached, can easily fit within the trouser leg of the wearer. The lower leg shell comprises a vertical lateral sidewall adjacent to the outside of the leg having a top and a bottom end, the bottom end being flared away from the leg to accept attachment of the hinging means, a vertical medial sidewall adjacent to the inside of the leg having a top and a bottom end, the bottom end being flared to accept attachment of the hinging means, a vertical rounded posterior wall having a top end and a bottom end adjacent to the rear of the leg and hooked fabric attachment material adhered to the top end of the lower leg shell to secure the lower leg shell to the wearer&#39;s leg. 
     The lateral mechanical joint is fixedly attached to the flared bottom end of the vertical lateral sidewall of the lower leg brace with screws and pivotally attached to the flared upright lateral sidewall of the foot shell. The medial mechanical joint is fixedly attached to the flared bottom end of the vertical medial sidewall of the lower leg brace with screws and pivotally attached to the flared upright medial sidewall of the foot shell. In this way, both rotational movement and translational movement are provided to the foot-ankle orthotic while sideways bending movement is restricted. 
     The pivoting means of the present invention is comprised of a bolt which passes through a hole defined through the end of the slider that projects out of the partially open side of the hinging means housing, and passes through the upright lateral or upright medial sidewall of the foot shell. A retaining nut, threaded onto the end of the bolt secures the slider to the foot shell and thereby allows rotational movement. 
     The spring means of the present invention is comprised of elastic rubber material that is placed above and below the end of slider that is positioned inside of the housing. When translational, upwards or downwards, movement of the slider occurs perpendicular to the axis of the ankle joint, depending on the force applied, then a return to a neutral position is facilitated by the elastic rubber material when the force causing the movement is removed. In this manner shock to the foot and ankle is absorbed by the foot-ankle orthotic. Wearer comfort is also aided, as rubbing of the leg by the orthotic is decreased, since the upper shell can move translationally with the leg instead of remaining stationary and scraping the lower leg. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description and accompanying drawings where: 
     FIG. 1 is a frontal perspective of the ankle-foot orthotic. 
     FIG. 2 is a frontal perspective of the lateral or medial mechanical joint. 
     FIG. 3 is a rear perspective of the lateral or medial mechanical joint. 
     FIG. 4 is an exploded view of the lateral or medial mechanical joint. 
     FIG. 5 is a cut away frontal view of the lateral or medial mechanical joint showing upward translational movement allowed by the lateral or medial mechanical joint when downward force, or tension, is applied to the ankle-foot orthotic. 
     FIG. 6 is a cut away frontal view of the lateral or medial mechanical joint showing the lateral or medial mechanical joint in its neutral position at equilibrium, when no forces are applied to the ankle-foot orthotic. 
     FIG. 7 is a cut away frontal view of the lateral or medial mechanical joint showing downward translational movement allowed by the lateral or medial mechanical joint when upward force, or compression is applied to the ankle-foot orthotic. 
    
    
     DESCRIPTION 
     Referring to FIG. 1, an ankle-foot orthotic  9  constructed in accordance with the invention comprises a foot shell  10 , a lower leg shell  12  and a hinging means  13  pivotally connecting the foot shell  10  to the lower leg shell  12 . 
     The foot shell  10 , which is molded to the shape of a specific wearer&#39;s foot, employing a moldable plastic material which creates a thin walled casing defining an internal surface  10   a  and an external surface  10   b , is comprised of a lower plate  20 , an upright lateral sidewall  22 , an upright medial sidewall  24  and rounded posterior wall  26 . The sole of the wearer&#39;s foot rests upon and is supported by the lower plate  20  while the heel of the foot is held by the rounded posterior wall  26  which extends upward from the lower plate  20  adjacent to and integral with both the upright lateral sidewall  22  and the upright medial sidewall  24 . The upright lateral sidewall  22  extends upward from the lower plate  20  on the outside of, and adjacent to the wearer&#39;s foot and ankle and terminates with a lateral flare  23  outward and away from the ankle, to allow clearance for the outside ankle bone and the slider  42  of the lateral mechanical joint  14 , at the axis of the ankle joint. The upright medial sidewall  24  extends upward from the lower plate  20  on the inside of, and adjacent to the wearer&#39;s foot and ankle and terminates with a medial flare  25  outward and away from the ankle, to allow clearance for the inside ankle bone and the slider  42  of the medial mechanical joint  16  at the axis of the ankle joint. The foot shell  10  thereby forms a casing to hold the foot and is designed to be worn snugly on a stockinged or bare foot inside of a shoe and be secured to the foot by the shoe itself. The foot shell  10  may also be trimmed or custom shaped for the comfort of the wearer. 
     The lower leg shell  12 , which is molded to the shape of a specific wearer&#39;s lower leg, employing a moldable plastic material which creates a thin walled casing defining an inner surface  12   a  and an outer surface  12   b , is comprised of a vertical lateral sidewall  30 , a vertical medial sidewall  32 , a vertical rounded posterior wall  34  and a means to secure  35  the lower leg shell  12  to the wearer&#39;s leg. The lower leg shell  12  is molded to the shape of the wearer&#39;s leg from just above the ankle to below the knee and has a gap  29 , opposite the vertical rounded posterior wall  34 , to allow insertion of the lower leg into the lower leg shell  12 . The vertical lateral sidewall  30  is adjacent to, and molded to the shape of the outside surface of the wearer&#39;s lower leg. The vertical lateral sidewall  30  has a lateral top end  30   a  and a lateral bottom end  30   b . The lateral bottom end  30   b  terminates with a lateral splay  31  outward and away from the outside of the leg, permitting clearance for the housing  40  of the lateral mechanical joint  14 . The vertical medial sidewall  32  is adjacent to, and molded to the shape of the inside surface of the wearer&#39;s lower leg. The vertical medial sidewall  32  has a medial top end  32   a  and a medial bottom end  32   b . The medial bottom end  32   b  terminates with a medial splay  33  outward and away from the inside of the leg, permitting clearance for the housing  40  of the medial mechanical joint  16 . The rounded posterior sidewall  34  is adjacent to, and molded to the shape of the rear surface of the wearer&#39;s lower leg. The rounded posterior sidewall  34  has a posterior top end  34   a  and a posterior bottom end  34   b  and is adjacent to and integral with the vertical lateral sidewall  30  and the vertical medial sidewall  32 . The lower leg shell  12  thereby forms a casing to hold the lower leg and is designed to be worn snugly on a stockinged or a bare lower leg inside the trousers of the wearer. A means to secure  35  the lower leg shell  12  to the leg is provided by a square of hooked fabric attachment material  38  adhered near the lateral top end  30   a  of the vertical lateral sidewall  30  and a strip of hooked fabric attachment material  36  fastened near the medial top end  32   a  of the vertical medial sidewall  32 . The strip of hooked fabric attachment material  36  is of sufficient length to reach across the gap  29  to the square of hooked fabric attachment material  38  and hook thereon, and subsequently secure the lower leg shell  12  to the leg. The lower leg shell  12 , as the foot shell  10 , may be trimmed or custom shaped for the comfort of the wearer. 
     Referring still to FIG.  1  and also to FIG. 2, FIG.  3  and FIG. 4, the hinging means  13  is comprised of a lateral mechanical joint  14  and a medial mechanical joint  16 . The lateral mechanical joint  14  and the medial mechanical joint  16  are identical in design and in function and act together to pivotally attach the foot shell  10  to the lower leg shell  12 , providing rotational and translational movement while restricting sideways bending movement of the ankle. The lateral mechanical joint  14  and the medial mechanical joint  16  are each comprised of a housing  40 , a slider  42 , a spring means  64  a cover  41  and a pivoting means  69 . 
     The hinging means  13  pivotally connects the foot shell  10  to the lower leg shell  12  by being fixedly connected to the upper leg shell  12  and rotationally connected to the foot shell  10 . The solid face  54  of the lateral mechanical joint  14  is secured to the inner surface  12   a  of the lower leg shell  12  at the lateral splay  31 , above the ankle joint, using screws  62  threaded into holes  67  of the housing  40  in a manner whereby the slider  42  is vertically in line with the wearer&#39;s lower leg. At the same time, the solid face  54  of the medial mechanical joint  16  is secured to the inner surface  12   a  of the lower leg shell  12  at the medial splay  33 , above the ankle joint, using screws  62  threaded into holes  67  of the housing  40  in a manner whereby the slider  42  is vertically in line with the wearer&#39;s lower leg. The lateral mechanical joint  14  and the medial mechanical joint  16  are also rotationally connected to the foot shell  10  each by said pivoting means  69 , which comprises a bolt  70  and a retaining nut  71 , on the internal surface  10   a  at the lateral flare  23  and at the medial flare  25 , respectively. Bolt  70  is threaded and inserted through hole  48  of the slider  42  of the lateral mechanical joint  14  and the lateral flare  23  while a second bolt  70  is threaded and inserted through hole  48  of the slider  42  of the medial mechanical joint  16  and the medial flare  25 , in each case the bolt  70  being secured in place by the retaining nut  71  threaded onto the bolt  70 , each mechanical joint at a position at, and in line with, the axis of the ankle joint, thereby permitting rotation at the ankle joint. 
     Referring to FIG. 1, FIG. 2, FIG.  3  and FIG. 4, the housing  40  is made of a lightweight and strong material, such as aluminum, and comprises a hollow interior  50 , an open face  52  that is open to the hollow interior  50 , a solid face  54  that is 180° opposite to the open face  52  and a partially open end  56  that is at 90° to the open face  52  open to the hollow interior  50 . The open face  52  has a threaded hole  58  defined at each corner sized to accept a screw  46 . The solid face  54  has a threaded hole  67  defined near each corner to accept a screw  62 . 
     The slider  42  is likewise made of lightweight strong material, such as aluminum, and comprises an upper end  43  and a lower end  44 . The upper end  43  is positioned freely inside of the hollow interior  50  of the housing  40  while the lower end  44  projects out through an opening  100  of the partially open end  56 . The slider  42  is rigidly constructed and is the same thickness as the depth of the hollow interior  50 . The upper end  43  is round in shape and fits tightly inside of the hollow interior  50  of the housing  40 . The upper end  43  is larger than the opening  100  of the partially open end  56  preventing the slider  42  from being removed through the partially open end  56 . The lower end  44  is configured to fit with very little clearance though the partially open end  56 . The combination of the shape of the slider  42  and the shape of the hollow interior  50  and the partially open end  56  of the housing  40  allows the slider  42  to move in only one direction inside of the housing  40 , which is in line vertically with the lower leg when the hinging means  13  connects the foot brace  10  to the lower leg brace  12 . The tight fit of the slider  42  in the hollow interior  50  and the partially open end  56  acts to keep the slider  42  from moving perpendicular to the lower leg in an axis forward and backward in line with the foot, while a cover  41 , that is attached over the open face  52  of the housing  40 , and flush to the slider  42 , by means of screws  46  through countersunk holes  60  in the cover  41  and into holes  58  in the open face . 52 , prevent the slider  42  from moving in an axis perpendicular, side to side, against the ankle joint. The slider  42  also has a hole  48  defined through its lower end  44  to receive the pivoting means  69 . Translational movement of the slider  42  in the housing  40  is thereby permitted while sideways bending movement is restricted. 
     The spring means  64  is located above and below the upper end  43  of the slider  42  inside of the housing  40 . The spring means is comprised of a flexible and elastic rubber material freely positioned inside of the housing  40 . An upper piece of rubber spring  66  is placed above the upper end  43  of the slider  42 . A lower piece of rubber spring  65  is placed beneath the upper end  43  of the slider  42  adjacent to each side of the lower end  44  of the slider  42  and above and next to the partially open end  56  of the housing  40 . The cover  41  will act to retain the spring means  64  inside of the housing  40 . 
     Referring to FIG. 6, the mechanical joint is in a state of equilibrium. No forces in tension or compression are being applied to the mechanical joint and thereby no forces are being applied to the spring means  64  which displays no deformity. 
     FIG. 5 shows tension being applied to the mechanical joint and the resulting deformity to the spring means  64 . The lower pieces of rubber spring  65  are being compressed by the slider  42  during this tension but act to absorb the shock of the tension and will return the slider  42  and the mechanical joint to a state of equilibrium when the tension is removed from the system. 
     In FIG. 7, the mechanical joint is being subjected to compressive forces. As a result the upper piece of rubber spring  66  is being compressed by the slider  42 . The upper piece of rubber spring  66  will act to cushion the shock of the compressive forces on the mechanical joint and will return the slider and the mechanical joint to a state of equilibrium when the compressive forces are removed from the system. 
     As shown in FIG. 1, FIG. 5, FIG.  6  and FIG. 7, the spring means  64  cushions and absorbs shock to the foot and ankle in up and down movement relative to the lower leg. The spring means also will return the ankle-foot orthotic  9  to a neutral position when forces in tension and compression are removed. Wearer comfort is improved by this cushioning but also further augmented since the hinging means  13  allows up and down movement along the axis of the lower leg of the foot shell  10  relative to the lower leg shell  12 , meaning the foot and foot shell  10  can move up and down but the lower leg shell  12  can stay in position around the lower leg. This will decrease rubbing of the lower leg shell  12  on the lower leg of the wearer, thereby increasing comfort. 
     Working together, the lateral mechanical joint  14  and the medial mechanical joint  16  provide full rotational movement for the ankle-foot orthotic  9  and consequently plantarflexion and dorsiflexion to the wearer&#39;s foot and ankle in an axis through the ankle. Sideways bending movement of the foot shell  10  and lower leg shell  12  relative to each other is restricted by the lateral mechanical joint  14  and the medial mechanical joint  16  working together, thereby restricting inversion and eversion of the foot. The translational, up and down movement, permitted by the hinging means  13  allows some sideways bending movement of the lower leg shell  12  relative to the foot shell  10  but such movement is limited and can be limited further by shortening the travel of the slider  42  in the housing  40  or by shortening the lower end  44  of the slider  42  itself. 
     It will be apparent from the above that the ankle-foot orthotic of the present invention provides a simple, strong, versatile, lightweight and inexpensive ankle-foot orthotic that can easily be worn on the inside of the shoe and trousers of the wearer, with all the inherent advantages of an inside orthotic described above. Moreover, this simple and inexpensive brace readily permits normal rotational and translational movement of the foot an ankle, while at the same time carefully restricting and controlling excessive turning movement, inversion and eversion, of the foot. The wearer thereby will be able to participate in athletic activities or merely walk or recuperate from an ankle sprain in comfort and confidence that a new or further ankle sprain will not occur. The wearer will not only have support and comfort, but also will not suffer from the embarrassment or self-consciousness of a bulky outside ankle brace. The present invention can be custom fitted to any wearer for either foot and adjusted to the comfort and physical needs of said wearer. 
     It should be readily understood by persons skillful in the art that the present invention is susceptible to a broad utility and application. While we have described the preferred embodiment of the invention, other embodiments and modifications could be implemented without departing from the spirit of the invention and from the scope of the appended claims. The foregoing disclosure is thus not intended to limit the present invention or otherwise to exclude any other such equivalent embodiments, adaptations, variations or modifications, the present invention being limited only by the claims appended hereto and the equivalents thereof.