PROSTHETIC FOOT
20180014949 · 2018-01-18
Inventors
- Stefan Grosskopf (Straubenhardt, DE)
- Felix Starker (Stuttgart, DE)
- Andreas Kramski (Pforzheim, DE)
- Andreas Adler (Kraichtal, DE)
- Urs Schneider (Stuttgart, DE)
- Jannis Breuninger (Großbettlingen, DE)
Cpc classification
A61F2002/6657
HUMAN NECESSITIES
International classification
Abstract
The invention relates to a prosthetic foot with a housing (12) on which a connector (15) for a below-knee prosthesis can be arranged, with a forefoot (21) and a heel (43), wherein the housing (12) and the forefoot (21) are connected by at least one forefoot spring element (28), wherein the forefoot (21) and the heel (43) are connected by at least one sole spring element (41), and wherein the heel (43) and the housing (12) are connected by at least one heel spring element (30), wherein the end portions belonging to the at least one forefoot spring element (28) and to the at least one sole spring element (41), and assigned to the forefoot (21), are positioned relative to each other with at least one holding mechanism (34) in such a way that the at least one forefoot spring element (28) and the at least one sole spring element (41) are guided movably relative to each other along their longitudinal axis during a rollover movement.
Claims
1. A prosthetic foot comprising a housing, on which a connector for a below-knee prosthesis is arrangeable, comprising a forefoot and a heel, in which the housing and the forefoot are connected by at least one forefoot spring element, in which the forefoot and the heel are connected by at least one sole spring element, and in which the heel and the housing are connected by at least one heel spring element, wherein the end portions of the at least one forefoot spring element and of the at least one sole spring element which are assigned to the forefoot are positioned in relation to one another, by means of at least one holding device, in such a way that the at least one forefoot spring element and the at least one sole spring element are guided displaceably relative to one another along their longitudinal axis during a roll-over movement.
2. The prosthetic foot according to claim 1, wherein the end portions of the at least one sole spring element and of the at least one heel spring element which are assigned to the heel are positioned firmly in relation to one another by means of at least one holding device, in the holding device.
3. The prosthetic foot according to claim 1, wherein the holding device of the forefoot and the holding device of the heel have at least one slit-like or U-shaped holding portion for receiving the respective end portions of the at least one forefoot spring element and sole spring element, and of the at least one sole spring element and heel spring element.
4. The prosthetic foot according to claim 1, wherein the end portions of the at least one forefoot spring element and of the at least one sole spring element which are assigned to the forefoot have a slot-like cutout or a U-shaped cutout, through which a fastening means of the holding device for positioning the forefoot spring element and sole spring element in the holding device extends.
5. The prosthetic foot according to claim 4, wherein the holding device of the forefoot comprises at least one holding portion and a clamping element, which form a receiving space for the end portions of the at least one forefoot spring element and the at least one sole spring element, and the holding portion and the clamping element are arrangeable at a predetermined distance from one another, and a sleeve is held clamped therebetween.
6. The prosthetic foot according to claim 1, wherein the end portions of the at least one forefoot spring element and of the sole spring element are fastened, in the forefoot, the end portions of the at least one sole spring element and of the heel spring element are fastened, in the heel, and the end portions of the at least one heel spring element and of the at least one forefoot spring element are fastened, at the housing.
7. The prosthetic foot according to claim 1, wherein the at least one forefoot spring element, the at least one sole spring element, and the at least one heel spring element form a fundamentally isosceles triangle which is formed by the at least one forefoot spring element and the at least one sole spring element, and the at least one heel spring element has a V-shaped extent, wherein the region of curvature of the V-shaped region points in the direction of the forefoot.
8. (canceled)
9. The prosthetic foot according to claim 1, wherein the at least one forefoot spring element, the at least one sole spring element, and/or the at least one heel spring element are/is formed as a strip-shaped spring element or forged leaf spring element.
10. (canceled)
11. The prosthetic foot according to claim 1, wherein the housing is formed as a foot upper part which has a connector portion, from which a foot upper side extends in a wedge-like manner in the direction of the forefoot and which comprises a bearing face arranged on the sole side, which bearing face extends from the distal end of the foot upper side to the heel region, which has a curvature, in a distal region, for forming a roll-over radius for the at least one forefoot spring element and runs in a rising manner to the heel region.
12. The prosthetic foot according to claim 11, wherein the housing has an end stop distally on the bearing face, which end stop delimits a curvature or bending of the forefoot spring element during a roll-over movement.
13. The prosthetic foot according to claim 1, wherein a dome directed towards the forefoot spring element is provided on the bearing face of the housing.
14-18. (canceled)
19. The prosthetic foot according to claim 11, wherein the at least one forefoot spring element extends freely to the forefoot starting from a fastening portion on the bearing face in the heel region, and the at least one forefoot spring element comes completely into abutment against the bearing face during a roll-over movement of the prosthetic foot.
20. The prosthetic foot according to claim 19, wherein a damping element forming the bearing face is provided between the fastening portion and a distal end of the bearing face.
21. The prosthetic foot according to claim 21, wherein the at least one forefoot spring element has the an imprint, which is directed in the direction of the damping element, at least in the region of the damping element forming the bearing face.
22. The prosthetic foot according to claim 1, wherein at least one sole spring element extends beyond the forefoot and forms a toe region and a strap acts on the front end of the toe region and extends along an underside of the sole spring element as far as the heel and through this or around this as far as the heel region of the housing, and is releasably fixed at the heel region.
23-24. (canceled)
25. The prosthetic foot according to claim 1, wherein the at least one forefoot spring element, sole spring element, and/or heel spring element are/is formed from high-grade steel, an aluminium alloy, a composite material, a steel alloy, or a soft metal.
26. The prosthetic foot according to claim 1, wherein the housing and/or the forefoot and/or the heel are/is produced from a plastic from a composite material or a fibre-reinforced plastic, or from a light metal.
27. The prosthetic foot according to claim 1, wherein the forefoot, transversely to the sole longitudinal direction, is wider than the housing and/or the heel and the forefoot has resiliently flexible supporting portions on one or both sides outside the holding portion for the end portions of the at least one forefoot spring element and sole element.
28-29. (canceled)
30. The prosthetic foot according to claim 1, wherein the housing has, at least on the foot upper side, a ribbed portion comprising a plurality of ribs, wherein the rigidity of the housing is adjusteable by the number and/or size and/or extent of the ribs.
31. A method for producing a prosthetic foot wherein: at least one forefoot spring element and heel spring element are connected to a housing, at least one heel spring element and sole spring element are connected to one another, and at least one forefoot spring element and at least one sole spring element are connected to one another, wherein the at least one heel sprig element and the at least one forefoot spring element, the at least one forefoot spring element and the at least one sole spring element, and the at least one sole spring element and the at least one heel spring element are connected to one another by means of a releasable connection and the at least one forefoot spring element, the at least one sole spring element, and the at least one heel spring element are encased by a protective film and then the assembly is provided at least approximately with the form of a natural foot by being covered in foam or vulcanised.
32-34. (canceled)
35. The prosthetic foot according to claim 25, wherein the at least one forefoot spring element, sole spring element, and/or heel spring element has a coating which is formed as a permanent coating or as a removable coating.
Description
[0041] The invention and further advantageous embodiments and developments thereof will be described and explained in greater detail hereinafter by means of the examples depicted in the drawings. The features to be inferred from the description and the drawings can be applied individually or together in any combination according to the invention. In the drawings:
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[0058] Various perspective views of a prosthetic foot 11 according to the invention are depicted in
[0059] The housing 12 forms a foot upper part and comprises a foot upper side 19, which extends in the direction of a forefoot 21. This foot upper part 19 is adapted to a natural profile of an instep of the foot. Opposite the foot upper part 19, there is formed a heel region 22, which is of a short height compared to the distal end of the foot upper side 12. A bearing face 24, which has a plurality of functional portions, extends on the sole side between the heel region 22 and a distal end of the foot upper side 19. In the heel region 22, the bearing face 24 comprises a fastening portion 26, at which at least one forefoot spring element 28 and at least one heel spring element 30 are fixed by a connection means 31. The connection means 31 is preferably provided as a screw connection. Alternatively, a clip, plug, detent or clamp connection or the like can be provided. The forefoot spring element 28 preferably bears against the bearing face 24 in the region of the fastening portion 26 thereof.
[0060] The fastening portion 26 of the bearing face 24 is adjoined in the distal direction by a damping element 33, in particular a damping cushion, against which the forefoot spring element 28 pointing towards the damping element 33 comes into bearing contact at least temporarily during a walking movement, as will be described hereinafter. The damping element 33 can advantageously extend as far as the distal end of the foot upper side 19. The flexibility of the damping element 33 advantageously can be adjusted.
[0061] The forefoot 21 is freely movable in relation to the housing 12, wherein the direction of movement and the scope of movement are determined at least by the at least one forefoot spring element 28. An end portion of the at least one forefoot spring element 28 opposite the heel region 22 is received and fixed in a U-shaped or slit-like holding portion 35 of a holding device 34 on the forefoot 21. The holding device 34 by way of example can be formed in two parts, wherein said holding device comprises supporting portions 36 adjacently to the holding portion 35 and also a clamping element 39, which engages between the supporting portions 36 so as to form the holding portion 35 and receive the end portions of the at least one forefoot spring element 28 and sole spring element 41. The supporting portions 36 can comprise longitudinal ribs, which extend along a foot axis, such that a transverse stability or increase of the standing strength of the prosthetic foot 11 is attained.
[0062] The holding device 34 fixes both the at least one forefoot spring element 28 and the at least one sole spring element 41.
[0063] Opposite the forefoot 21, there is a heel 43 provided, which receives an end portion of the sole spring element 41 opposite the forefoot 21 and also an end portion of the heel spring element 30 in a holding device 45. For this purpose, the holding device 45 comprises a holding portion 35, similarly to that of the holding device 34, in which holding portion 35 the end portions of the at least one sole spring element 41 and of the at least one heel spring element 30 are received.
[0064] The end portions of the at least one forefoot spring element 28 and of the at least one sole spring element 41 arranged in the holding portion 35 of the holding device 34 preferably have slot-like cutouts 38, through which fastening means, in particular releasable fastening means 17, such as screws, are engaged so as to fix the end portions of the at least one forefoot and sole spring element 28, 41 in the receiving space 44, however receive these displaceably relative to one another. By way of example, the at least one forefoot and at least one sole spring element 28, 41 each have a slot-like cutout 38, such that the forefoot and sole spring elements 28, 41 are held by the holding portion 35 in a manner lying one on top of the other, but are displaceable relative to one another along their longitudinal axes in the holding portion 35. By way of example, a bore can also be provided in one of the two spring elements 28, 41, and a slot-like cutout can be provided in the other of the two spring elements 28, 41, such that, on the one hand, the holding device 34 is fixed to one of the two spring elements 28, 41 and the other of the two spring elements 28, 41 is displaceable relative thereto in order to attain improved roll-over properties. Alternatively to the slotlike cutouts, a U-shaped cutout can also be formed, which is open at an end side pointing into the holding portion 35. The receiving space 44 is formed by a holding portion 35 and a clamping element 39. This receiving space is open at least on one side. The clamping element 39 and the holding portion 35 are positioned relative to one another by a releasable connection 40. The releasable connection 40 is preferably formed as a screw connection, such that by way of example a threaded bolt extends through the slot-like cutouts 38 of the at least one forefoot and sole spring element 28, 41.
[0065] A sleeve 42 is fastened between the holding portion 35 and the clamping element 39 of the holding device 34, in particular is pressed or held clamped between the holding portion 35 and the clamping element 39, such that the receiving space 44 has a defined height and the forefoot and sole spring elements 28, 41 can lie loosely one on top of the other and remain displaceable relative to one another. The sleeve 42 is inserted into the slot-like cutouts 38 of the forefoot and spring sole element 28, 41. If a smaller number than the maximum number of forefoot and sole spring elements 28, 41 that can be fastened to the holding portion 35 is used, a compensation adapter can be used instead of the un-used spring element 28, 41. The space left by the absent spring element 28, 41 can thus be bridged. A compensation adapter of this type can be formed as a round disc or an insert element for fixing to the sleeve 42.
[0066] A preferred embodiment of this type is depicted schematically in an enlarged manner in
[0067] The above embodiments and alternatives can apply similarly for the heel 43 and the at least one sole spring element 41 and heel spring element 30 arranged therein. However, the holding device 45 of the heel 43 preferably has a holding portion 35 and a clamping element 37, by means of which a receiving space 44 is formed, in which the end portions of the at least one sole spring element 41 and of the at least one heel spring element 30 are received and fixed firmly in relation to each other.
[0068] A damping element 48, in particular a damping rubber, is provided between the heel 43 and the heel region 22 of the housing 12 and can also be fixed to the heel region 22 by the connection means 31. This damping element is fixed opposite the heel 43 for example by clamping, or is merely supported thereon. The degree of damping can be adjusted by the selection, for example, of the Shore hardness.
[0069] At least one sole spring element 41 extends preferably through the forefoot 21 and forms a toe region 51. At the front end of the toe region 51, a rounded portion 52 is preferably provided. This toe region 51 is flexible and yielding in relation to the forefoot 21, such that this toe region 51 also constitutes a roll-over region. Alternatively, a separate toe region 51 can also be integrally formed on, or fastened to the forefoot 21.
[0070] A strap 54 extends from the toe region 51, in particular starting from an upper region of the toe region 51, over the rounded portion 52 and along an underside of the sole spring element 41 as far as the heel 43 and through this to the heel region 22 of the housing 12. This strap 54 is fixed by way of example to the toe region 51 and at the opposite end is also fixed, preferably releasably, to the fastening means 31. This strap 54 can also be fastened non-releasably in the heel region 22. This strap 54 can be fixed in such a way that a pre-tension and tensile stress acts between the two clamping points of the strap 54 in order to adjust the harmony or dynamics of the roll-over process.
[0071] In the depicted exemplary embodiment, the forefoot spring element 28, the sole spring element 41, and the heel spring element 30 are each formed as a strip-like spring element, in particular a leaf spring element, which for example has the same strip width. Alternatively, the spring elements can all differ from one another in terms of the strip width. The same is true for the material and/or the wall thickness and/or coating thereof. In order to adjust a spring characteristic curve or in order to adapt the prosthetic foot 11 to the individual wearing it or to the individual using it, one or more forefoot spring elements 28, sole spring elements 41 and/or heel spring elements 30 can be provided. By way of example, both the spring characteristic curve and the roll-over behaviour can be adjusted by the number of respective spring elements 28, 41, 30. Furthermore, the snap-action effect can be adjusted for example with regard to the number of forefoot spring elements 28 and/or the imprint formed therein, such that for example forefoot spring elements 28 with or without imprint 46 are combined with one another or forefoot spring elements 28 with different imprints are also combined with one another. By way of example, the snap-action effect during a walking movement can thus be made noticeable for the individual wearing the prosthetic foot, such that a traceable dynamic can thus be attained. Furthermore, when selecting a plurality of forefoot spring elements 28, sole spring elements 41 and/or heel spring elements 30, different strip-shaped spring elements can also be selected, which deviate from one another in terms of the material and/or the wall thickness and/or the characteristic curve.
[0072] The at least one forefoot spring element 28, the at least one sole spring element 41, and/or the at least one heel spring element 30 can be easily exchanged by the releasable connections provided at the forefoot 21 and the heel 43 and at the housing 12, so as to enable a quick and individual adaptation of the prosthetic foot to the individual wearing it. In particular, an adaptation both to the weight and to the walking habits of the individual wearing the prosthetic foot is possible. In addition, a quicker exchange is provided at the time of maintenance.
[0073] In the present exemplary embodiment, the heel spring elements 30 are U-shaped or V-shaped, wherein the region of curvature thereof points in the direction of the forefoot 21. Alternatively, they can also be V-shaped in the region of curvature. By way of example, three heel spring elements 30 are provided, which are each clamped at one end to the heel 43 and at the other end between the damping element 48 and the heel region 22. The sole spring elements 41 are advantageously formed as flat, strip-shaped spring elements, which extend in a straight line. These constitute the connection between the forefoot 21 and the heel 43. At the same time, they form a supporting face for the heel spring elements 30.
[0074] The forefoot spring elements 28 constitute a connection between the heel region 22 of the housing 12 and the forefoot 21 and can decisively determine the roll-over behaviour or the roll-over shape.
[0075] To this end, the forefoot spring elements 28 preferably have an imprint 56 in the region of the damping element 33, by means of which the spring characteristic curve of the respective forefoot spring elements 28 is determined. By providing the imprint 56, a non-linear characteristic curve is attained for the forefoot spring characteristic curve, wherein this is set in such a way that, as the individual wearing the prosthetic foot walks, a dynamic rolling of the prosthetic foot from heel to toe is made possible, wherein in particular, just before push-off via the toe region 51, a sort of catch-spring effect occurs on account of the imprint and a recovery of energy and an improved lifting of the prosthetic foot from the floor are thus obtained. The roll-over behaviour can be determined by the length of the bearing face 24 and the curvature thereof and also the selection and number of the one or more forefoot spring elements 28 and the imprint 56.
[0076] The length of the foot upper side 19 or the extent of the bearing face 24 in the direction of the forefoot 21 determines a delimitation of an acting overload and can also be adapted accordingly to the weight of the user.
[0077] The at least one forefoot spring element 28, the at least one heel spring element 30, and the at least one sole spring element 41 are directly connected to one another in the region of the fastening points thereof, i.e. in the fastening portion 26 at the heel region 22 and in the holding portions 35 of the forefoot and of the heel 43, and form a closed triangle, such that they cooperate with one another and influence one another. Here, the at least one forefoot spring element 28 and the at least one sole spring element 41 fundamentally determine the rollover behaviour, whereas the at least one heel spring element 30 fundamentally determines the cushioning as the prosthetic foot 11 touches down.
[0078]
[0079] The pre-tensioning device 61 according to
[0080] By means of this pre-tensioning device 61, a pre-tension can be applied to the damping element 48 in the heel region 22 and can be permanently maintained. This pretension is adapted individually to the individual using the prosthesis and the body weight of said individual.
[0081] The above-presented and described prosthetic foot 11 can be used directly in this embodiment. However, it is preferably provided that the presented prosthetic foot 11 is encapsulated in foam and provided with a protective film, or that a foam encapsulation is provided after the prosthetic foot is surrounded by a protective or shrink film, or a rubber mixture is vulcanised onto the protective or shrink film, such that the form of a natural foot is mimicked. The foam material can serve here as an additional damping element.
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[0083] In accordance with a first embodiment, the inside of the shoe 74 is lined with a film 75, which protrudes from the shoe 74 at the area at which a foot is inserted into the shoe. The prosthetic foot 11 is then inserted into the shoe 74. The interior of the shoe 74 is then filled with foam or injected, whereby the film 75 is pressed closely against the inner walls of the shoe 74 and the prosthetic foot 11 is encased by the foam material 76 or injected material. Before the prosthetic foot 11 is encapsulated in foam, it can be directly surrounded by a protective film 77 or shrink film, such that the foam material 76 or the injection-moulding material extends externally around the prosthetic foot 11 and encases this, with the protective film 77 or shrink film being embedded. The foam material 76 thus does not infiltrate the gaps between the spring elements 28, 30, 41, such that the individual functionalities of the prosthetic foot 11 are maintained.
[0084] Once the foam material 76 or injected material has cured, the prosthetic foot 11 is removed from the shoe 74, and the film 75 is removed. The prosthetic foot 11 is thus adapted to the specific shoe size and/or a specific shoe form of the individual using the prosthetic foot.
[0085] If, when filling the shoe 74 with foam when using a prosthetic foot 11, an integral foam is used, it is sufficient as a preparatory measure that the inner walls or the interior of the shoe 74 are/is sprayed with a release agent. Here, it is not necessary to slide out the prosthetic foot with a film 75.
[0086] In
[0087]
[0088] This embodiment according to
[0089] Furthermore, this embodiment differs from the above-described embodiment in
[0090]
[0091] In this embodiment, the bearing face 24 extends along the width of the forefoot spring element 28 and is delimited on either side by a lateral shoulder 82. These shoulders enable the at least one forefoot spring element 28 to be guided relative to the bearing face 24 as the prosthetic foot rolls from heel to toe, since the right and left shoulders 82 are each guided, respectively, along a right and left longitudinal edge of the forefoot spring element 28 during said rolling of the prosthetic foot from heel to toe.
[0092] Alternatively, at least one forefoot spring element 28 can be used with an imprint 56 in combination with a damping element 33 formed as a layer.
[0093] In this preferred embodiment, it is provided that the foot upper side 19 of the housing 12 is formed by a ribbed portion 95. This ribbed portion 95 comprises a plurality of ribs 96. Here, both longitudinal ribs and transverse ribs or a combination of longitudinal ribs and transverse ribs can be provided. The rigidity of the housing 12 can be influenced by the width, size and/or number of the ribs 96 and also the orientation thereof, that is to say the housing can have a greater or lesser resilience.
[0094] In this embodiment depicted in
[0095] The foot orthosis depicted in
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[0098] The further alternative embodiments of the above-describe prosthetic feet 11 can also be provided in the case of this prosthetic foot 11.
[0099] It can also be seen from the plan view according to
[0100] It can also be seen from