DE102004020368B4 - Artificial jointless foot - Google Patents

Abstract

Artificial jointless foot with an elastically deformable heel structure (9) extending in a height direction from a sole region to an ankle region and an elastically deformable forefoot structure (10) extending in the longitudinal direction from ankle region to a toe region, the heel structure (9) and / or the Forefoot structure (10) at least two elements (2, 5; 2, 11) which are arranged one behind the other in the height direction of the heel structure (9) or in the longitudinal direction of the forefoot structure (10) and which can be moved and form a variable space (3; 22, 23) and with an actuating mechanism which can be activated by the walking process, characterized by an element which can be controlled by the activated actuating mechanism and which engages in the variable intermediate space (3, 22, 23) in a manner influencing the distance between the limbs (2, 4; 2, 11) , and by a resetting mechanism acting depending on the walking process smus for the controllable element.

Description

The invention relates to an artificial jointless foot having an elastically deformable heel structure extending in a height direction from a sole region to an ankle region and an elastically deformable forefoot structure extending in a longitudinal direction from the ankle region to a toe region, the heel structure and / or the forefoot structure being at least two in Height direction of the heel structure or in the longitudinal direction of the forefoot structure arranged one behind the other, to each other movable and have a variable gap between them forming members, and with an activatable by the walking operation mechanism.

Such a foot is for example from the WO 02/034 173 A2 known.

It has long been known to form artificial feet in jointless form, so that the performance characteristics of the artificial foot are determined by the elastic deformability of the material used for the foot construction. There are numerous constructions known with which in particular the gait characteristics of the artificial foot to be improved. This is the case, for example US 4,652,266 A known to form the forefoot area in several parts and connect with each other by elastic joints.

It is also known to form the heel part and forefoot by leaf springs in combination with air-filled cushions, whereby the suspension of the aisle can be varied by the air pressure in the cushions. By EP 0 884 033 B1 It is also known to form the forefoot by two mutually parallel leaf springs, between which an air-filled pressure pad is arranged. By loading the heel part of the air pressure in the pressure pad is influenced, so that in a dynamic gait with a strong heel strike an increase in the spring hardness of the forefoot is made. Similarly, this is achieved with a spacer between the two leaf springs whose position is shifted in response to the heel strike. The principle of these solutions is thus the adjustment of the spring stiffness as a function of the gait dynamics.

A fundamental problem for the design of an artificial foot is to find a suitable compromise for the fitness of the foot for its main uses, namely walking and standing. For a secure standing on an artificial foot would be a hard, long forefoot suitable, which would convey a high sense of security. However, with such a hard and long forefoot no usable gait dynamics can be realized. For walking, so the rolling over the forefoot, it is advantageous to form a shortened and soft forefoot, with which, however, a secure feeling when standing is not feasible. The compromises that have been made so far, that allow both natural walking as well as safe standing, are satisfactory, but not optimal because of the need to compromise.

From the DE 3232373 A1 An artificial foot is described which has a deflectable toe part to enable conditions as in a natural gait.

The DE 303 735 A discloses an artificial foot with articulated lower leg, in which the movement of the lower leg is used to move foot parts relative to each other and thus imitate the natural gait.

Also from the DE 285 672 A An artificial foot is known, which has joint points, which bring themselves into the correct position and can be set or removed by a blocking means by the user.

From the EP 0 893 111 A1 For example, a prosthetic foot is known that has an energy storage means in a heel mechanism which stores energy as it emerges and releases it as it unwinds to more easily lift the foot off the ground.

From the US 2004/0 064 195 A1 For example, a prosthetic foot is known which has control means for controlling the stiffness and spring rate of spring elements used in the foot so that the mechanical behavior of healthy feet can be mimicked in different movements.

From the DE 326 131 A For example, an artificial foot is known that can properly unroll over its entire length because a plurality of elements are positioned in the foot which are connected by joints.

The present invention has for its object to improve an artificial foot of the type mentioned in its use properties.

To solve this problem according to the invention an artificial jointless foot of the type mentioned above is characterized by an activated by the activated actuating mechanism element which engages in the space in a distance between the members influencing manner, and by a function of walking acting return mechanism for the controllable element.

In the artificial foot according to the invention is thus directly intervened by the movable member in the structure of the heel part and / or the forefoot part. The invention thus does not exhaust itself to adjust the spring stiffness of the forefoot, but provides for a reversible change in the construction of the heel part and / or forefoot part by means of the member movable by the actuating mechanism. In particular, according to the invention, an artificial foot can be created in which the movable member is designed and arranged such that it changes the effective length of the forefoot for the walking process and / or the height of the heel part by its movement. According to the invention it is therefore possible to use a different structure of the foot for standing than for the walking, so that the need to compromise between the properties of the foot when walking and standing, eliminated or at least mitigated, since due to the modification of the Construction is suitable for going a different structure of the foot than for standing.

The actuating mechanism which moves the member may in suitable embodiments be triggered by a deformation of the heel part or by a dorsal deformation of the forefoot part. The deformation of the heel part makes it possible to detect a firm appearance, which indicates that a walking cycle is being carried out. The provision can be activated in this case, for example, by a dorsal deformation of the forefoot part, so that the provision takes place during the swing phase. When standing, the heel part is regularly not so heavily loaded, so that in this case the actuating mechanism is not activated. The induced by the heel strike displacement of the limb must therefore be such that the effective length of the forefoot shortened to facilitate walking. If the heel part is not loaded, it remains at a greater effective length of the forefoot part.

It is also possible to trigger the actuating mechanism by a dorsal deformation of the forefoot part, which indicates that the prosthesis wearer is in a walking motion, so that the shortening of the forefoot part is performed for the next step. The provision can be effected by an example mechanical timer, which is by the actuating mechanism triggering action of the foot, so for example the Dorsalverformung the forefoot part, resettable, so that the return mechanism is only effective if the corresponding action is omitted until the expiration of the timer.

Activation of the actuation mechanism may also be from outside the foot, for example, by a moment sensor on a lower leg prosthesis.

The moving member by the actuating mechanism may be a rigid lever which is switchable between two positions and bridges in one of these positions an elastic connecting member between relatively less elastic parts of the forefoot part. If the actuating mechanism is triggered by a deformation of the heel part, the rigid lever is moved to the position in which it does not bridge the elastic connecting member, so that the elastic connecting member during walking shortens the effective length of the forefoot part. The provision can be made by the return mechanism, which is activated in this case by a dorsal deformation of the forefoot lever, so that the provision is made at the end of each rolling process while walking and re-triggered by the placement of the heel.

The member moved by the actuating mechanism may further be a rigid element, for example in the form of a wedge, which is movable into a wedge-shaped space. The wedge-shaped gap is deformable by the load in the direction of reduction of the wedge. This deformation is prevented by the movement of the rigid element into the wedge-shaped gap. The actuation mechanism for the element can be activated by both the heel strike and the dorsal deformation of the forefoot part. As a return mechanism is preferably a mechanical timer, which is reset by a movement of the foot. By moving the rigid element into the wedge-shaped intermediate space, the forefoot part can be made more rigid in the region of the intermediate space, so that the meaningful configuration for standing is realized and the wedge has to be moved out of the wedge-shaped intermediate space for a detected walking process. Alternatively, the rigid member may be pulled into the wedge-shaped space for the walking motion when the wedge-shaped gap is in the heel portion, for example, and the effective height of the heel portion is increased by the rigid member moving into the gap, thereby providing the effective length during walking of the forefoot part is reduced.

In another embodiment of the invention, the actuation mechanism may include a pumping arrangement for a fluid, and the element controllable by the actuation mechanism may be a fluid fillable pad disposed in the space. For such an embodiment, a return mechanism is in shape a timer particularly useful. As fluid preferably air or a liquid can be used.

The return mechanism can also be operated from outside the foot, for example by means of a guided out of the foot assembly Bowden cable, which can also be operated manually.

The invention will be explained in more detail below with reference to exemplary embodiments illustrated in the figures. Show it:

1 A schematic side view of the internal structure of an artificial foot in a first embodiment of the invention in three different phases

2 A schematic side view of the internal structure of an artificial foot in a second embodiment of the invention in three different phases

3 A schematic side view of the internal structure of an artificial foot in a third embodiment of the invention in three different phases

4 A schematic side view of the internal structure of an artificial foot in a fourth embodiment of the invention in two different phases

5 A schematic side view of the internal structure of an artificial foot in a fifth embodiment of the invention in two different phases.

In all drawing figures, a foot insert of an artificial foot is shown, which in a known manner by a cosmetic case 1 is surrounded.

The foot insert has a fixed adapter member 2 with an adapter facing an ankle area 2 ' on, to which a further (not shown) prosthesis part can be connected. The adapter member 2 is over a wedge-shaped gap 3 with an approximately horizontally extending plate-shaped approach 4 over a hinge piece 5 connected. In the wedge-shaped gap 3 is an elastic wedge 6 used. Under the plate-shaped approach 4 there is a paragraph piece 7 , which may be formed of a likewise elastic material, but whose hardness is substantially greater than that of the elastic wedge 6 , Between the paragraph piece 7 and the plate-shaped approach 4 there is a rear portion of a plate-shaped spring element 8th , The adapter member 2 , the elastic wedge 6 , the plate-shaped approach 4 , the rearward portion of the plate-shaped spring element 8th and the paragraph piece 7 form a heel construction 9 thus extending in a height direction from the heel area to the ankle area of the artificial foot.

The plate-shaped spring element 8th extends into a tough area of the artificial foot and has a forefoot structure 10 extending longitudinally of the foot from the adapter member 2 extends in the ankle area to the toe area of the artificial foot.

The forefoot construction 10 consists of longitudinally successively arranged rigid members 11 . 12 . 13 . 14 . 15 . 16 . 17 . 18 . 19 as well as two elastic pontics 20 . 21 , The rigid limbs 12 to 19 adjacent to each other and allow due to their shape only a slight tilt to each other. Between the adapter member 2 and the first rigid member 11 is a first elastic intermediate member 20 and between the first rigid link 11 and the second rigid member 12 a second elastic intermediate member 21 arranged. The elastic intermediate links 20 . 21 extend over the entire height of the forefoot body 10 and thus fill corresponding spaces 22 . 23 between the rigid limbs 2 . 11 on the one hand and 11 . 12 on the other hand.

The foot structure thus described thus consists of a heel structure 9 in the vertical direction and from a forefoot structure 10 in the longitudinal direction, both consisting of several members.

At the in 1 illustrated embodiment is at one of the first elastic member 20 directed edge of the adapter member 2 a rigid lever 24 rotatably mounted, the free end 25 in the in 1 phase shown a) on an L-shaped paragraph 26 of the first rigid member 11 supported. The lever 24 thus bridges the gap 22 between the adapter member 2 and the first rigid member 11 , so that the first elastic intermediate member 20 can not be compressed.

At the plate-shaped approach 4 of the adapter member 2 There is a downward-facing approach 28 that has a flexible band 27 with the free end 25 of the lever 24 connected is.

In a strong heel load, as occurs in the phase b), as occurs when walking, the elastic wedge 6 in heel construction 9 compressed, thereby increasing the approach 28 relative to the adapter member 2 turns back and so on with the flexible band 27 the free end 25 of the lever 24 from the L-shaped paragraph 26 of the first rigid member 11 pulls out. This is the first elastic intermediate member 20 no longer by the lever 24 bridged and can thus be pressed resiliently in an advantageous manner for walking, resulting in the effective forefoot length for walking is shortened by the amount Δl as shown in 1 is shown.

When rolling the artificial foot over the forefoot structure 10 becomes the plate-shaped spring element 8th bent dorsally (upwards). This bend is used in the first embodiment to form a return mechanism. This is due to the plate-shaped spring element 8th in the area of the forefoot near the toe area, ie for example in the ball area, another flexible band 29 attached, also with the free end 25 of the lever 24 connected is. Due to the dorsal bending of the plate-shaped spring element 8th becomes the other flexible band 29 cocked and pulls the lever 24 with his free end 25 in the L-shaped paragraph 26 back, whereby the phase according to a) is reached again. The phase a) with the extended effective Vorfußaufbau 10 is advantageous for a secure feeling of the prosthesis wearer. The advantageous for walking c) phase is automatically reset when walking continues, so again a strong heel load according to phase b) is made.

In this way, an automatic adjustment of the effective forefoot length of the artificial foot for standing on the one hand and walking on the other hand succeeds.

This in 2 illustrated embodiment has a principle consistent with the first embodiment heel structure 9 and forefoot construction 10 on. In the wedge-shaped gap 3 Here, however, is a rigid wedge 6 ' in addition, in the interspace 3 Slidably mounted in the longitudinal direction. The sliding movement of the wedge 6 ' is with a handlebar 30 controlled, rotatably on an arm of a two-armed lever 31 is articulated. The two-armed lever 31 is on the adapter member 2 rotatably arranged. To the other arm of the two-armed lever 31 is another handlebar 32 hinged, firmly with a rigid member 14 of the forefoot construction 10 connected is.

In the in 2 represented phase a) is the wedge 6 ' to the rear partly from the wedge-shaped gap 3 shifted out so that by the burden of the patient's weight of the gap 3 according to the still effective part of the wedge shape 6 ' is small. The artificial foot in this phase a) thus has a low heel height. The low heel height corresponds to a large effective forefoot length and thus creates a secure feeling when standing.

According to the phase b) in 2 the forefoot construction 10 by rolling extensively deformed and the heel structure 9 relieved, as is the case when walking, the handlebar acts 32 as a drawbar and twisted the two-armed lever 31 counterclockwise. As a result, it works with the wedge 6 ' connected handlebars 30 as a pull rod and pulls the wedge 6 ' in the wedge-shaped gap 3 into what, because of the relief of the heel structure 9 is possible. As a result, on the one hand, the heel height is increased and the effective forefoot length is reduced, so that a comfortable walking is possible.

The provision in the favorable for standing phase a) can be done with a (not shown) return mechanism, for example, manually via a Bowden cable.

At the in 3 illustrated embodiment is again an elastic wedge in the heel structure 6 used. The first gap 22 between the adapter member 2 and the first rigid member 11 is wedge-shaped and in the phase a) of 3 through a rigid wedge 20 ' filled. Because of the gap 22 now has a maximum size, a maximum effective forefoot length is set in this phase, which is favorable for standing.

The wedge 20 ' is with a side boom 33 provided in the phase a) of the 3 on the plate-shaped approach 4 rests. The boom 33 is in turn with a in the adapter member 2 in a cylinder arrangement 34 guided piston 35 rigidly connected. In the cylinder 34 there is a return spring 36 that the piston 35 biased in the heel direction. At the bottom of the cylinder 34 there is a throttle valve 37 with which by the return spring 36 caused return movement of the piston 35 through the throttle valve 37 slowly escaping air is delayed.

If the patient leaves the standing phase shown in phase a) and begins to walk, he applies his weight to the heel in phase b) and presses the elastic wedge 6 together. This will cause the side boom 33 pushed up, leaving the wedge 20 ' is moved upwards. This will create the gap 22 between the adapter member 2 and the first rigid member 11 reduced, the effective forefoot length thus shortened. This makes walking easier. The setting of the throttle valve 37 is chosen so that at a normal walking pace while walking still no provision of the wedge 20 ' he follows. Only if for a certain time no heel action with the compression of the elastic wedge 6 takes place, worried the return spring 36 ' the provision of the wedge 20 ' over the boom 33 in the position according to phase a).

At the in 4 illustrated embodiment, the first space 22 between the adapter member 2 and the first rigid member 11 designed so that in him a pillow 38 is storable. In the wedge-shaped gap 3 of the heel construction 9 is a pumping arrangement 39 housed with a fluid from the pillow 38 in a pantry 40 via a check valve 41 is pumpable. This will drain the pillow 38 , which eliminates the gap 22 reduced and the effective forefoot length according to phase b) is shortened for walking. If the heel action disappears because the prosthesis wearer is standing, the pillow fills up 38 from the pantry 40 via a throttle valve 42 and a check valve 43 slowly, which increases the effective forefoot length according to phase a) and supports standing.

At the in 5 illustrated fifth embodiment is also a cushion 44 used this in the wedge-shaped interspace 3 is used, but of course in a gap 22 . 23 of forefoot construction could be.

The pillow 44 is by means of an air pumping arrangement 45 inflatable, which is like the pumping arrangement 39 in 4 in the wedge-shaped gap 3 is used, but here directly the pillow 44 inflates.

For the return of the inflated cushion 44 this may be connected to a blow-off port via a throttle valve (not shown). If no heel action takes place (when walking), the pillow is emptied 44 to the state shown in phase a). The reduction in the height of the heel body 9 causes a larger effective forefoot length and thus supports standing.

By pumping up the pillow 44 becomes the height of the heel body 9 increases and thus shortens the effective forefoot length, thereby assisting walking in phase b).

The illustrated embodiments show that a change in the effective forefoot length triggered by a foot action itself is achieved by either the actual length of the forefoot structure 10 is increased or the height of the heel structure 9 is reduced. The actuation of the corresponding controllable members may be triggered by a heel action or by a bend of the foot to dorsal. Similarly, a return mechanism can be controlled by a foot action. Also possible are manual or temporally controlled provisions.

Claims (14)

Artificial jointless foot having an elastically deformable heel structure extending from a sole region to an ankle region in a height direction ( 9 ) and an elastically deformable forefoot structure extending in the longitudinal direction from the ankle area to a toe area (US Pat. 10 ), wherein the heel structure ( 9 ) and / or the forefoot structure ( 10 ) at least two in the height direction of the heel structure ( 9 ) or in the longitudinal direction of the forefoot structure ( 10 ) arranged one behind the other, movable relative to each other and a variable gap ( 3 ; 22 . 23 ) between forming members ( 2 . 5 ; 2 . 11 ), and with an activatable by the walking operation mechanism characterized by an activated by the actuation mechanism actuatable element which in the variable space ( 3 . 22 . 23 ) in one the distance between the links ( 2 . 4 ; 2 . 11 ) engaging manner, and by acting as a function of walking return mechanism for the controllable element. Artificial foot according to claim 1, characterized in that the actuating mechanism by a deformation of the heel structure ( 9 ) is triggered. Artificial foot according to claim 1, characterized in that the actuating mechanism by a deformation of the forefoot structure ( 10 ) can be triggered dorsally. Artificial foot according to one of claims 1 to 3, characterized in that the element controllable by the actuating mechanism is a rigid lever ( 24 ), in one position the variable gap ( 22 ) bridged. Artificial foot according to one of claims 1 to 3, characterized in that the variable gap ( 3 . 22 ) a wedge-shaped gap ( 3 . 22 ) and the element controllable by the actuating mechanism is a rigid element ( 6 ' . 20 ' ), which is in the wedge-shaped space ( 3 . 22 ) is movable into it. Artificial foot according to claim 5, characterized in that the wedge-shaped intermediate space ( 22 ) in the forefoot structure ( 10 ) is located. Artificial foot according to claim 5, characterized in that the wedge-shaped intermediate space ( 3 ) in the heel construction ( 9 ), so that the inserted element ( 6 ' ) an increase in the height of the loaded heel structure ( 9 ) causes. Artificial foot according to one of claims 1 to 3, characterized in that the actuating mechanism is a pump arrangement ( 39 . 45 ) and that the element controllable by the actuating mechanism is in the variable space (FIG. 3 . 22 ), fillable with the fluid cushion ( 38 . 44 ). Artificial foot according to one of claims 1 to 8, characterized in that the return mechanism by a deformation of the forefoot structure ( 10 ) is dorsally activated. Artificial foot according to one of claims 1 to 8, characterized in that the return mechanism comprises a timer, which triggers the provision and by the actuating mechanism triggering action of the foot is reset. Artificial foot according to one of claims 1 to 10, characterized in that the forefoot structure ( 10 ) of a plurality of links ( 11 to 19 ) which are relatively movable relative to each other. Artificial foot according to one of claims 1 to 11, characterized in that the actuating mechanism can be activated by a sensor arrangement arranged outside the foot. Artificial foot according to one of claims 1 to 12, characterized in that the return mechanism can be activated from outside the foot. Artificial foot according to claim 13, characterized in that for the activation of the return mechanism, a Bowden cable is led out of the foot assembly.

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