RO130150B1 - Dynamic ankle orthosis - Google Patents

Description

The invention relates to a dynamic ankle orthosis, intended for patients with a fallen foot, which will allow them to improve walking, approaching the normal one, and which will contribute to the rehabilitation of the lower limb.

Several ankle orthoses are known, in which the bracelet that is mounted on the calf and the part of the orthosis that attaches to the foot are connected by means of a structure, placed behind the calf and the foot, formed by two rotating couplings between which is a system dynamic mechanical or pneumatic type that includes a translation torque capable of changing, as needed, the distance between the said rotating couplings so that, during walking, the movements of the foot in relation to the leg occur naturally, in the patient's ankle and other joints from the foot, without these movements being influenced by the orthosis, as happens if the bracelet is tied to the rigid shoe or through a hinge.

From a functional point of view, the dynamic system acts, through the two rotating couplings, on the bracelet and the part of the orthosis that attaches to the foot with sufficient force to rotate the foot around the ankle until it reaches a state of equilibrium where it is approximately perpendicular to the calf, after which, whenever the respective balance is broken, the system reacts by correspondingly changing the value and possibly the sense of the force it develops, so that the balance is restored.

Known dynamic mechanical systems, with which the orthoses are equipped (FR 497992/1909, FR 2953127/2011, FR 2953128/2011, FR 2953129/2011) or other devices (US 5144943/1992) intended for patients with fallen legs, are formed in generally, from a helical spring located inside a cylindrical tube, closed to one of the ends, in which the spring is compressed by means of a second cylindrical tube or a rod, which enters the first, thus creating the force necessary to achieve the equilibrium state. of the leg in relation to the leg. Among the disadvantages specific to such dynamic systems can be mentioned:

- the forces developed by the arc cannot be too large, these being limited by the fact that, with the increase of the force, both the weight and the dimensions of the system that generate them increase;

- adjusting the value of the force developed by the arc to the needs of the patient is difficult to achieve in the absence of a means of fine tuning its compression, this disadvantage is not an easy one to eliminate, as there are examples (US 5144943/1992) which show that such means of adjustment it can complicate the dynamic system, increasing its weight and price.

Also known are other dynamic systems made with pneumatic or hydropneumatic cylinders (EP 1382317/2004, FR 2842412/2004), capable of developing large forces and whose values can be adapted to the patient's weight (EP 1382317/2004) with the help of a valve. pressure regulation (claim 3, EP 1382317/2004) so that the equilibrium state in which the foot is approximately perpendicular to the leg (claim 4, EP 1382317/2004) can be achieved.

The aforementioned dynamic systems, whether mechanical, pneumatic or hydropneumatic, have several common disadvantages, namely:

- the dynamic instability of the system which, in the absence of a damper, when returning to the equilibrium position oscillates on one side and the other;

- reduced efficiency in taking over the shock produced at the contact of the foot with the ground;

- the impossibility of ensuring a slow movement of the soles of the foot on the ground, caused, among other things, by the sudden variation of the reaction force when losing the balance of the foot relative to the leg.

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Also known are a series of orthotics provided with an engine servosystem called system pump, which is in the form of a pneumatic cylinder with several chambers (2 or 3) and other interior elements which increase its complexity [2]. The main disadvantages of these braces are the high price and the relatively low reliability [1], [3].

The part that attaches to the foot of this type of orthotics can be an ice bucket with a caliper (FR 497992/1909), or a shoe in which a special insole is inserted (EP 1382317/2004, FR). 2953127/2011, FR 2953128/2011, FR 2953129/2011), elements through which the dynamic system acts on the shoe and the foot to achieve the equilibrium state of the latter in relation to the leg.

The main disadvantage of the clamping foot with ice and caliper is that it does not allow to travel on rough terrain when, in contact with the ground, under the action of the patient's weight, the heel of the boot tends to lean left or right, thus requiring the dynamic system, which can rapidly deteriorate.

The shoe insole variant has a number of drawbacks caused by the fact that it has to meet several conditions, difficult to achieve simultaneously, namely: to be customized, in the sense of having anatomical shapes and dimensions adapted to each patient's foot, to be thin enough to be fitted into the shoe without major changes, made of lightweight materials with superior mechanical properties, not to greatly increase the weight of the orthotic and to withstand the demands it is subjected to, not to be expensive, the tip of his shoe not to embarrass while walking, etc.

The technical problem solved by the present invention is the realization of a dynamic ankle orthosis which, while walking, when the lower limb of the patient is lifted off the ground, keeps the foot in a balanced position. When the lower limb is placed on the floor, the orthosis supports the foot, so that its contact with the ground is achieved through the heel, and the lowering of the sole is made smoothly and without risk of producing sprains, even if the ground has bumps, and, subsequently, when the lower limb is removed from the floor, it helps to first raise the heel and then the tip of the foot, through the forces that the respective orthosis develops to return to the aforementioned position of balance.

Dynamic ankle orthosis, according to the invention, composed of a leg bracelet, from which is articulated a dorsal structure consisting of a pneumatic cylinder having a body and a piston extended outwardly with a rod, the dorsal structure being in connection with a shoe subassembly, the connection between the cuff bracelet and the shoe subassembly being made by a set of straps made of a pair of side straps, solves the technical problem and removes the aforementioned disadvantages by having the piston divide the cylinder body into two communicating chambers between them by several longitudinal bores processed in the piston, the air being introduced into the body of the cylinder at an initial pressure through bores provided in a pneumatic cylinder stopper, opening the air circuit or sealing to maintain a certain pressure in the cylinder being realized with one screw with axial displacement and the rod from The extension of the piston is provided at the free end with a body that forms a spherical joint with a spherical axis welded by a plate on which steel plates are assembled for connection with the shoe subassembly.

The invention has the following advantages:

- has high reliability, being conferred both by the mechanically fixed outer support of the heel and the back of the shoe, which is capable of transmitting great forces to the foot, as well as from the pneumatic cylinder whose operation does not require a very good seal of the camera the piston of the piston by means of the gasket on the piston, since the two chambers of the piston communicate in any case by means of bores provided in the piston, which makes the risk of deterioration or improper operation thereof being minimal;

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- involves reduced manufacturing costs, due both to the pneumatic cylinder which, given its operation in the absence of a very good seal made by the gasket on the piston, can be one of poorer quality and consequently cheaper, as well as the materials from which they are made the other elements of the orthosis, which, being not some special ones, are relatively inexpensive, but the economies that result from the elimination of the special insole, encountered in many orthoses of this type, and from some constructive simplifications, which are presented below, are not to be neglected;

- it can develop large forces by correspondingly increasing the pressure, without the need for the orthosis to have the special adjustment means, because the desired value of the force is obtained by properly adjusting the filling pressure value of the pneumatic cylinder, made by a pneumatic pump, or provided by an air bottle;

- it has vibration stability, this being conferred by the frictional force between the oring rubber gasket of the piston and the surface of the cylinder cavity, the force of which can be modified by the corresponding dimensioning of the piston channel into which the respective gasket is inserted;

- ensures a slow placement of the foot on the ground, by creating an additional resistive force, which opposes the ankle movement limiting its speed, as happens with the contact of the heel with the ground when, under the action of the patient's weight, the rod and piston tend to be pushed. rapidly inside the cylinder, however, when the speed of this movement exceeds a certain threshold, corresponding to the maximum air flow that can pass through the piston holes, an increase in pressure in the piston chamber occurs, accompanied by a decrease in the piston chamber, which determines the occurrence of the aforementioned additional force, which is opposed to the movement of the rod and the piston that created it, and whose value is determined by both the piston section and the pressure difference between the two chambers of the pneumatic cylinder;

- the inside of the orthosis shoe, as well as that of the pair of the orthosis, remain unchanged, which makes, from this point of view, the same working conditions for both legs of the patient are ensured, and the possible discomfort caused by the presence inside is eliminated. the shoe of some elements of the special insole type orthosis, as well as the disadvantages mentioned above in connection with the use of the respective insoles;

- does not present a risk of producing sprains under the action of the important lateral forces, which may occur when walking on uneven ground, due to the high capacity to take over these forces, conferred by both the constructive features of the side belts and the particularly robust mechanical grips their bracelets and shoe holster;

- If necessary, the positioning of the sole can be improved when it is placed on the floor, by using one or two front straps.

An example of embodiment of the invention is given below, in connection with FIG. 1 ... 10, which represents:

FIG. 1, perspective view of an orthosis according to the invention, mounted on the calf and foot;

FIG. 2, axial section according to the direction A-A of fig. 1;

FIG. 3, axial section according to the direction B-B of fig. 1;

FIG. 4, axial section according to the C-C direction of fig. 1;

FIG. 5, axial section according to the direction D-D of fig. 1;

FIG. 6, axial section according to the E-E direction of fig. 1;

FIG. 7, axial view and section following the F-F direction through a side strap;

FIG. 8, axial section according to the direction G-G of fig. 1;

FIG. 9, partial axial section according to the direction G-G of fig. 1;

FIG. 10, a view from the direction H of fig. 8.

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Fig. 1 shows a dynamic ankle orthosis according to the invention, the main components of which are: a bracelet A, a shoe assembly B, a set of straps C and a dorsal structure D. The orthosis is mounted on the lower member of patient 1, of which, in FIG. 1, leg 1a, leg 1b and ankle 1c are presented.

The bracelet A contains a dorsal support 2, which can be made of a thermoset plastic material, inside which it is glued with an adhesive, or sews, a lining 3, made of sponges or a soft fabric, as well as some belts. 4 and 5, and a buckle 6, with which the bracelet is attached to the patient's leg 1a, the belt 4 being velcro. Both straps, 4 and 5, are fastened by the dorsal support 2 with some rivets 7 and washers 7a, which does not embarrass the patient, since, upon riveting, the linings from the lining 3 are buried in it, deforming or perforating it, so as can be seen in section AA of fig. 2.

For attaching the set of straps C, of the bracelet A, on the outer side of the calf (section BB in fig. 3), a special screw 8 is used, which has a shoulder a and a cylindrical section b, so dimensioned as to allow the rotation of the ends of the belts around the axis of said screw, which is inserted by threading into a special nut 8a, fixed by the dorsal support 2, together with a washer 8c, by the plastic deformation of its thinner end, more precisely of an extension c, a to the respective nut. Since mounting the orthosis on the lower limb of the patient does not involve the repeated removal of the special screw 8, it can be secured against the screwing of the special nut 8a, by applying a suitable adhesive or varnish on the threads of the two.

Similarly, the strap set C of the bracelet A is realized, on the inner side of the calf (section CC in fig. 4), for this a special screw 9 is required, which is inserted by threading into a special nut 9a , fixed by the back support 2, together with a washer 9c. Because, for removing or mounting the orthosis on the lower limb of the patient, it is necessary that the special screw 9, together with the straps on it, be removed from the bracelet A, by screwing, and then mounted on it by screwing, the respective screw is provided a striped surface d, which allows the respective handles to be executed manually, without the need for various tools, and a thread 9c was inserted on its thread, which prevents the straps from coming out on the cylindrical section b, for this, the respective washer must be sized. so that it can only enter the thread by twisting, like a nut, and can only be removed by the same movement, executed in the opposite direction.

The shoe subassembly B is composed of an ordinary shoe 10, in which the leg of the patient 1b enters, and an outer support made of steel strips 11, 12 and 13, assembled with rivets 14, together with a plate 15, to which a spindle is drawn. spherical 16, said support being mechanically fixed to the heel (sections DD and EE in Figs. 5 and 6), with inner threaded tubes 17 and 18, provided at the ends with screws 19 and 20, and at the rear of the shoe, with a screw 21, the screws 19 being provided with sections e and f, which have the same role as the sections a and b from the screws 8 and 9.

The strap set C, contains some side straps 22, preferably in number two, which are fastened by the bracelet A and the shoe assembly B, with the screws 8, 9 and 19, but it may be possible to add another two straps. by the ends of the threaded rod 18, and the same screws 8 and 9, these side belts having several functions, namely: not to allow the A bracket to be raised on the calf under the action of the forces developed by the dorsal system D, to avoid the production of sprains when moving on rugged terrain, and to contribute with the aforementioned dorsal system D, both in achieving the balance position of the foot in relation to the leg, as well as in its correct positioning on the ground. The side straps 22 are composed of strips 22a,

RO 130150 Β1 provided at the ends with some metal staples 22b, assembled by breaking their tubular portion over some washers 22c (fig. 7). The internal diameter of the metal staples 22b must be slightly larger than that of the sections of the screws 8, 9 and 19 on which they are mounted, so that the straps can be easily rotated relative to the axes of the respective screws.

Optionally, the belt set C may also contain some front straps composed of laces 23, which are tightened with clips 24, so that their length has the value corresponding to the correct orientation of the sole of the foot, both in relation to the leg and to the leg. with the soil to be laid. All these belts can be made of leather or other materials that allow them to be flexible, without significantly stretching in case of tensile stresses that may occur during walking.

The dorsal structure D contains a pneumatic cylinder, consisting, inter alia, of a body 25, provided at one end with a stopper 26, which is attached, by means of a bolt 27, to a bearing 28, fixed in its turn by the support dorsal 2, with rivets 29 and washers 29a (figs. 1 and 10), as well as a rod 30 which protrudes through the other end of said body, the thread of which is inserted by screwing a body 31, which, together with the spindle 16, forms a spherical joint, and which is secured against the unscrewing with a nut 32, thus linking said dorsal structure D to the shoe subassembly B.

The rod 30 is fixed by deformation of its non-threaded end, until a protrusion g, a piston 33, framed by a washers 34, which divides the cavity of the body of the pneumatic cylinder 25 in a chamber of the piston h, and a rod chamber are formed. i, said piston being provided with both one or more longitudinal bores j, through which the two aforementioned chambers communicate with each other, and with a gasket 35, which acts as a vibration damper, this rubbing on the inner surface of the body of the cylinder. pneumatically, when between it and the piston there are relative displacements (fig. 8). For sealing the two chambers h and i of the pneumatic cylinder with respect to the outside, between its body 25, and the rod 30, a gasket 36 is provided and the fixing of the stopper 26, in the body 25 is made by means of a previously painted threaded assembly, thus so that, after drying the paint, both the sealing of the joint and its securing against the unscrewing are realized.

The desired value of the pressure in the h and i chambers of the pneumatic cylinder is achieved by introducing or removing the pressurized air in / out of them, through a circuit formed by bores k, I and m, made in plug 26, which communicates between they, said circuit can be closed or opened, by rotating in a proper direction a screw 37, with the help of a screwdriver, introduced through the bore n of the bearing 28, which drives the said screw through a notch o, moving it axially, together with a rubber stopper 38, located in the front bore thereof. The horizontal bore I is formed by a threaded section, on which the corresponding threaded end of the screw 37 enters, followed by a cylindrical section, on which the gasket 39 is sealed, located in a channel p, practiced on the respective screw, which section continue with a truncated transition surface q, towards the final cylindrical section, with the smallest diameter.

In order to have a certain pressure in the pneumatic cylinder, in the threaded bore k a screw 40 is provided, provided with a gasket 41, through which it is supplied with a pressure air hose, coming from a pump or from an air cylinder, which, if screw 37, is in the retracted position, as in FIG. 9, enters the piston chamber h, and subsequently in the rod chamber i, increasing the pressure to the desired value, and if the respective value is exceeded, the surplus of air will travel in the opposite direction, outwardly, as indicated by the arrow r. In order to maintain the regulated value of the pressure in the cylinder, it is isolated from the outside by actuating the screw 37, so that it presses the rubber stopper 38 on the truncated surface q, sufficiently strong to achieve a tight seal.

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The dorsal structure D can rotate, in relation to the bracelet A, around the axis of the bolt 27, which assembles the stopper 26, with the bearing 28 and which is secured against the opening with an elastic washer 42, inserted in a channel s of the respective bolt (fig. 10), and the shoe assembly B can rotate, in turn, with respect to the said dorsal structure, around the spherical joint, composed of the spherical axis 16 and the housing 31, so that the forces transmitted through this joint give components after three directions in space, which means that, at any given moment, there is at least one component of the aforementioned force that contributes to achieving the equilibrium position of the foot in relation to the leg and to the movements of the ankle after its axis of rotation.

Bibliography [1]. Pneumaflex Foot Relief Brochure - Scribd - page 3 / comments http://www.youscribe.com/catalogue/tous/art-nuisique-et-cinema/autres/medical brochure- pneumaflex-reliever-foot- 364 280.

[2] . PNEUMAFLEX3® foot lifting orthese. Why an anatomical involvement? http://www.youtube.com/watch?v=nF7d80Dilpl.

[3] . Pneumaflex france or switzerland http://forum.pneumaflex.com/discussion-general-f2/pneumaflex-france-ou-suisse-t168.html.

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Claims (4)

1. Dynamic ankle orthosis composed of a bracelet (A) for the leg, from which a dorsal structure (D) consisting of a pneumatic cylinder having a body (25) and a piston (33) extended outwardly with a rod (30), the dorsal structure (D) being connected to a shoe assembly (B), the connection between the bracelet (A) for the calf and the shoe assembly (B) being made by a set of straps (C) made of - a pair of side belts (22), characterized in that the piston (33) divides the body of the cylinder (25) into two chambers (h, i), which communicate with each other through several longitudinal bores (j) processed in the piston (33) ), the air being introduced into the body of the cylinder (25) at an initial pressure through bores (m, I, k) provided in a plug (26) of the pneumatic cylinder, opening the air circuit or sealing to maintain a certain pressure in the cylinder. by means of a screw (37) with displacement axial, and the rod (30) of the extension of the piston (33) is provided at the free end with a body (31) which forms a spherical joint with a spherical axis (16) welded by a plate (15) on which are assembled flat plates from steel (11,12, 13) for connection with the shoe assembly (B). 2. Dynamic ankle orthosis according to claim 1, characterized in that the dorsal structure (D) is fixed by the bracelet (A) by a dorsal support (2) of thermoset plastic material, provided internally with a lining (3), by by means of a bolt (27) caught in a bearing (28), which allows the rotation around the flexion axis - extension of the foot, the bracelet (A) by fastening the calf with some belts (4, 5) and a buckle (6) ). 3. Dynamic ankle orthosis according to claim 1, characterized in that the steel plates (11, 12, 13) take the request and transmit it to the shoe subassembly (B) by a fastening system on the heel and on the back of the shoe sole, made of inner threaded tubes (17,18), provided at the ends with screws (19, 20) that take over the forces and tensions generated by the dorsal system (D) and allow the belts (22) to rotate from the set of belts (C) . 4. Dynamic ankle orthosis according to claim 1, characterized in that the respective straps (22) of the belt set (C) are provided at the ends with some staples (22b) mounted on screws (8, 9,19) for fastening of the bracelet (A), respectively of the shoe assembly (B), so that the straps (22) can be rotated relative to the axes of the screws, in order to take over the stresses that appear when walking on rough terrain.