Prosthesis part insert

Abstract

To provide a prosthesis part insert which makes optimal behaviours possible when standing up and walking and gives sufficient stability without sacrificing comfort during walking especially when walking.SOLUTION: A prosthesis part insert (10) includes: a. a proximal fitting device (20) for fixing a prosthesis part insert (10) to a proximal component (2) or a patient; b. a holder (30) which is arranged away from the fitting device (20) and is connected to the fitting device (20); and c. a main spring (40) which extends to a toe part area and is coupled to the holder (30). The holder (30) is supported by the main spring (40) tiltably on a sagittal plane, and a rear restriction element (92) restricting movement of the holder (30) in the direction away from the main spring (40) is disposed between the main spring (40) and the holder (30).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a prosthetic foot insert comprising a proximal attachment device for fixing the prosthetic foot insert to a proximal component or to a patient, a holder disposed distally of and connected to the attachment device, and a main spring extending into the toe region and coupled to the holder. [Background technology]

[0002] The prosthetic foot insert is part of a prosthetic prosthesis, for example in transtibial amputees. The prosthetic foot insert can be provided with a covering or prosthetic cosmetic element, which may be made of plastic, in order to obtain a look as natural as possible and to provide other functionalities. The prosthetic foot insert can be attached to the ankle joint or without a joint to the calf tube or calf socket. The attachment device is usually formed as a so-called pyramid adapter, via which the various adjustments and alignments of the prosthetic foot insert relative to the proximal component, i.e. the calf tube, the prosthetic socket or the ankle joint, can be adjusted and set. The attachment device is attached to a holder, on which a spring extending in the toe direction, for example a toe spring or a roof spring, can also be arranged. To cushion the heel strike, an elastic heel element is provided, which is attached to the holder, possibly via an intermediate object. Examples of prosthetic inserts are described in EP 2420212 A, EP 1976463 A, US 2005 / 0038525 A or EP 2688522 A.

[0003] Problems with the prior art prosthetic foot inserts are the required mounting space, the poor sinking behavior, the uneven rolling behavior, and the difficulty of compensating for unevenness. Furthermore, complex geometries are sometimes required, which increases the manufacturing costs and makes optimal material utilization difficult. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] European Patent Application Publication No. 2420212 [Patent Document 2] European Patent Application Publication No. 1976463 [Patent Document 3] US Patent Application Publication No. 2005 / 0038525 [Patent Document 4] European Patent No. 2688522 Summary of the Invention

[0005] The object of the present invention is therefore to provide a prosthetic foot insert which allows optimal behavior when standing and walking and which provides sufficient stability, especially when walking, without sacrificing walking comfort.

[0006] According to the invention, this problem is solved by a prosthetic foot insert having the features of the main claim. Advantageous embodiments and developments of the invention emerge from the dependent claims, the following description and the figures.

[0007] The prosthetic foot insert comprises a proximal attachment device for fixing the prosthetic foot insert to a proximal component of the prosthesis or to the patient himself, a holder arranged distal to and connected with the attachment device, and a main spring extending to the toe region and coupled with the holder, wherein the holder is supported on the main spring so as to be tiltable in the sagittal plane, and a rear limiting element is arranged between the main spring and the holder, which limits the movement of the holder away from the main spring. The prosthetic foot insert is formed as a separate part that can be fixed to a distal prosthetic component, e.g. a calf tube or calf socket, or as a prosthetic foot insert manufactured together with a corresponding attachment device for fixing to the patient or user of the prosthetic foot insert, e.g. a device for bone-direct fixation to the patient or as an integrated part of the calf socket.

[0008] The prosthetic foot insert may in particular be used as a base for other structures such as mechatronic joints, ML adapters, adapters for adjusting heel height, hydraulic joint units, or the like.

[0009] The rear limiting element prevents the holder from moving away from the main spring beyond a previously adjusted limit. The rear limiting element defines the maximum distance between the rear end of the holder and the main spring, in particular the rear end of the main spring, while still allowing the opposite movement. This does not prevent or only negligibly prevents the contraction of the prosthetic foot insert during heel loading or heel strike, while providing sufficient stability when the toe is loaded during rolling movements or forward bending during standing, thereby limiting the forward tilting about the tilting axis in the sagittal plane in addition to the elastic deflection that is basically possible during standing.

[0010] The main spring may be formed as a spring consisting of at least one distal spring and / or at least one proximal spring. In the case of, for example, two distal springs, the proximal spring forms the inner spring and the distal spring forms the base spring, or bottom spring, which preferably extends to the heel region of the prosthetic foot insert. The proximal spring is assigned to the holder or a guide element for the holder. All springs are formed in particular as leaf springs. The leaf springs may have a substantially rectangular cross section and may have a uniform thickness in the longitudinal extension or a thickness that varies, in particular decreases in the anterior direction. The springs may be formed with slits in the toe region to allow a medial-lateral tilting of the prosthetic foot or to form openings or cuts to accommodate, for example, a finger strap of a sandal or the like.

[0011] The distal and proximal springs of the main spring are preferably spaced apart and fixed to each other to allow for contraction of the prosthetic foot under load and to utilize the individual spring properties of the separate springs. The springs are in particular made of composite materials, in particular fiber-reinforced plastics. The springs can be made of glass fibers, carbon fibers, aramid fibers, Kevlar® fibers, Dyneema fibers, or other particularly high-strength fibers embedded in a matrix, or a combination of these.

[0012] In one development of the invention, the distal and proximal springs are biconvexly shaped and aligned with each other to form an enlarged space in the central area between these two springs. The space is formed approximately elliptical and allows for contraction over a relatively long spring displacement in the midfoot area or toe area. The proximal springs can be formed and aligned with each other in a biconvexly shaped manner as well. If the shape between the distal spring and the medial spring is biconvex, a space can be formed in the rear area between the distal spring or base spring and the medial spring that expands in the rear direction to allow for deep contraction of the holder in the direction of the base spring or bottom spring.

[0013] A development of the invention provides that the guide elements are attached to the front or rear region of the main spring, respectively extending in opposite directions, and that the holder is supported on the main spring via the guide elements, preferably pivotable about a pivot axis perpendicular to the sagittal plane. By supporting the holder on the main spring via the guide elements, different supports and movements can be adjusted and changed, so that the number of variants can be individually adapted or increased. In that case, the holder is not directly connected and fixed to the main spring, for example by screwing a leaf spring directly to the underside of the holder base, but can be pivoted about an axis transverse to the walking direction, for example via a guide element, hinge or other intermediate element that allows a relative movement of the main spring and the holder.

[0014] The guide element can be attached to the front or rear region of the main spring, in which case the rear region of the attachment device is located behind the attachment device or the pyramid adapter, in particular behind the force introduction point when standing. The front region is located in front of the attachment device, e.g. the pyramid adapter, or the position of the ground reaction force vector occurring when standing. The guide elements extend in opposite directions from the respective attachment region of the guide element, i.e. forward when attached to the rear region and backward when attached to the front region. The holder is supported on the main spring so that it can be tilted in the sagittal plane around the guide element, whereby the guide element allows a pivoting movement of the holder relative to the main spring and a vertical movement.

[0015] One development provides for a front limiting element to be arranged between the guide element and the holder or the main spring, which limits the movement of the front end of the holder or the main spring away from the guide element during heel loading. As in the case of the rear limiting element, the front limiting element prevents the holder from moving relative to the main spring during certain loading phases in order to influence the contraction and extension behavior of the prosthetic foot insert. By adjusting the length of the front and / or rear limiting element, the tension of the spring can be changed and an adaptation of the energy transfer behavior of the foot during different gait phases can be performed. Similarly, by changing the bias and / or length to limit the movement of the front and / or rear end of the holder, an adaptation to different usage habits, purposes of use of the respective user, or to different users or to different or changing physical characteristics of the respective users, etc. can be performed.

[0016] To ensure a precise adjustment of the possible movements and distances of the spring relative to the holder, limiting element or guide element, the respective limiting element can be made tensile-strong and flexible, for example as a belt, cable or string or also as a sleeve guide with a stop element for limiting the maximum distance respectively.

[0017] In particular, the bias of the limiting element or elements is adjustable in order to make the difference between walking with impact load and standing with static load perceptible. During walking, in particular during heel strike, but also during rolling movements, damping should occur with corresponding mutual movement of the components. When standing, the user should be provided with a sense of stability achieved by the bias of the holder against the spring-elastic element. The bias is preferably 5% to 60% of the user's body weight, in particular the bias is 5% to 40% of the user's body weight, particularly preferably 10% to 25% of the user's body weight. In the last mentioned case, the bias of the holder by the limiting element or elements against the spring action of the main spring or other spring-elastic element or component can be 10 kg to 25 kg for a user weight of 100 kg, which corresponds to a force of approximately 98.1 N to 245.25 N.

[0018] The main spring and the guide element are preferably formed as leaf springs, in particular as straight leaf springs, which has the advantage that the production of the spring components is particularly simple. In particular if the main spring or the individual spring components of the main spring are produced from fiber-reinforced plastic, the main spring as a whole can be formed relatively stiff, which increases its durability. A stiff spring design of the individual spring components allows for a high durability of the spring components, but this does not result in a particularly stiff prosthetic foot insert at heel strike, since a stiff spring design can be compensated for by a relatively large spring displacement and a long force transmission path. The guide element can likewise be formed as a leaf spring, in particular as a metal leaf spring in the form of a spring tongue. Alternatively, the holder can be supported on the main spring via a hinge or at least one spacer element, whereby the guide element is formed as a spring tongue, hinge or spacer element.

[0019] To further adjust the walking behavior and for improved adaptability of the rolling behavior and protection of the distal spring or the distal part of the main spring, a toe cushion and / or a heel cushion can be attached to the main spring, for example glued, screwed or fitted or, especially in the case of the heel cushion, held via a respective limiting element. The cushions are preferably arranged on the base spring or bottom spring.

[0020] A development of the invention provides that the force from the holder to the main spring is introduced via a front force introduction area and a rear force introduction area, the force introduction area extending in front or behind the attachment device, respectively. Thereby, it is possible for the holder to be supported on the main spring at two spaced apart points or areas in the longitudinal extension of the main spring, possibly via an intermediate element, intermediate plate or damping device, possibly also via the intermediate spring. Support in this force introduction area allows a reduction of point loads and a controlled introduction of forces in different load scenarios. The force introduction area is preferably located between two end supports, on which the main spring is supported in its distal area, for example between the spring cushion and the toe cushion. Thereby, when the patient is in the stance phase and the foot strikes the ground, at least one four-point bending is performed, whereby the introduction of forces is distributed over a relatively wide area, so that the maximum bending moment of the main spring is considerably reduced.

[0021] At least one of the force introduction areas can be movably or exchangeably supported on a holder or main spring, whereby the spring characteristics and the energy transfer characteristics of the prosthetic foot insert can be changed during use by adjusting the position of the respective force introduction area. The adjustment of the respective position of the force introduction area is preferably done only once in order to adapt the behavior of the prosthetic foot insert to the respective user and can be adjusted and adapted before each use. In principle, it is also possible to change the position of the force introduction area by means of a motor. The respective motor or drive can then be adjusted by the control and sensor assembly during walking in order to allow adaptation to different speeds, loads or walking situations.

[0022] At least one damping device can be arranged between the holder and the main spring to gently create a new contact between the holder and the main spring after the holder in the front or rear region is released from the main spring or to damp the pivoting movement. This avoids the generation of disruptive force peaks and impulses due to the contact between the holder and the main spring during walking, which can make the patient's rolling behavior uneven and uncomfortable. The pivoting behavior of the holder relative to the main spring can also be adjusted.

[0023] The holder can be supported on the main spring at an adjustable proximal-distal distance to allow for angular adjustment and variation in engagement behavior and time of engagement, and therefore energy transfer.

[0024] One development of the invention provides that in the unloaded state of the prosthetic foot insert, the main spring is elastically biased against the guide element by the limiting element and / or by multiple limiting elements, so that in the unloaded state the individual components of the prosthetic foot insert are held solely by the bias of the main spring relative to the guide element.

[0025] The limiting elements or one limiting element acts between the holder and the main spring. A guide element is arranged between the main spring and the holder, and the prosthetic foot insert is stable in the abutment state without a separate fixing device of the component, as long as only vertical forces occur, i.e. no horizontal displacement forces occur. The separate fixing device or mounting element serves only for fixing against the occurring lateral or shear forces. To be able to make an adaptation to different requirements or patients, the mounting device can be displaceably and / or articulatedly supported on the holder.

[0026] As long as the mounting device is fixed to the holder as a separate element, a damper can be arranged between the mounting device and the holder, which can allow a slight relative movement between the mounting device and the holder and reduces load peaks and allows a uniform rolling movement without impulses.

[0027] A development of the invention provides for exchangeable and / or displaceable contact elements to be arranged between the proximal and distal springs and / or between the distal springs, via which the respective force introduction points and the connection times and points between the distal and proximal springs or between the distal springs can be fixed, adjusted or adjusted. By means of exchangeable and / or displaceable contact elements, the contraction behavior and the force transmission behavior of the prosthetic foot insert can be easily changed and adapted.

[0028] The holder can be tiltably supported on the main spring in a positionally variable plane in the sagittal plane, so that the holder can roll on the main spring during loading and move relative to the main spring, whereby the holder does not have a fixed point of rotation relative to the main spring, but rather the point of rotation of the holder displaces during the rolling process.

[0029] The prosthetic foot insert is particularly suitable and intended to be adapted to different heel heights or desired inclination angles, so that the user can easily perform an individual adaptation. This can be done in particular by changing the length of one or more limiting elements. The respective limiting elements are exchanged or lengthened or shortened and then fixed at the desired length, for example tightened. The holder can be adjusted and fixed in the desired angular position relative to the floor or the main spring, for example by exchanging cushions, damping devices, intermediate pieces, inserts or spacer elements between the holder and the main spring, whereby an optimal alignment of the holder and the attachment device is achieved. An adaptation to the respective heel height can be achieved by alignment and fixing in the desired position based on a pivotable bearing in front of or behind the vertical line by the attachment device. The position of the bearing point or axis can be made adjustable in order to achieve the alignment and the adaptation of the heel height. If a hydraulic or pneumatic damper or an adjustment cylinder is present, the desired attitude and orientation of the holder can be adjusted by opening and closing the valve. The holder is supported on the main spring with an adjustable proximal-distal distance, which allows adaptation to different sole thicknesses of the shoe when the distance is changed uniformly. When different distances are changed at the front and rear sides of the mounting device, the inclination of the holder is adapted as desired. For this purpose, the front and rear distances can be adjusted individually as described above by adjusting the adjusting cylinder or damper device or by inserts or the like.

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 is a schematic cross-sectional view of a first embodiment of a prosthetic foot insert. [Diagram 2] FIG. 2 is a variation of FIG. 1 having a hinge. [Diagram 3] FIG. 2 is a view of a variant of FIG. 1 in which the guide elements are folded. [Figure 4]FIG. 13 shows a variant of the invention in which the holder projects backwards. [Figure 5a] FIG. 2 is a view of a variation of FIG. 1 in which the cushion is in a loaded state. [Figure 5b] FIG. 2 is a view of a variation of FIG. 1 in which the cushion is in a loaded state. [Figure 5c] FIG. 2 is a view of a variation of FIG. 1 in which the cushion is in a loaded state. [Figure 6] FIG. 13 shows a variant of the invention having a cushion between the guide element and the main spring. [Figure 7] FIG. 7 is a diagram of a variation of FIG. 6. [Figure 8] FIG. 1 shows a variation having one hinge and two springs. [Figure 9] FIG. 9 is a diagram of a variation of FIG. 8. [Figure 10] FIG. 13 shows a variant in which the holder has a height adjustment device. [Figure 11] FIG. 1 shows a variant having two springs guided substantially parallel and one base spring curved in opposite directions. [Figure 12] FIG. 13 shows a variation in which the contact between the holder and the main spring is movable. [Figure 13] FIG. 13 shows a variant having a cover. [Figure 14] FIG. 13 shows a variant of the invention having a delay element. [Figure 15] FIG. 15 is a diagram of the prosthetic foot insert according to FIG. 14 under load. [Figure 16] FIG. 15 is a view of the prosthetic foot insert according to FIG. 14 in a tilted position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] 1 shows a schematic cross-sectional view of a prosthetic foot insert 10 with a proximal attachment device 20 in the form of a pyramidal adapter, which is reversibly fixed to a proximal component 2 in the form of a lower tube. Instead of the attachment device 20 in the form of a pyramidal adapter, it is possible for the attachment device 20 to have a receiving portion for a transtibial stump or a bone-direct connection to the bone. The attachment device 20 can be formed integrally, for example within an additive manufacturing process, and at the same time form a stump receiving portion. It is also possible for the proximal component 2 to be formed integrally with the attachment device 20, for example also in an additive manufacturing process.

[0033] Disposed distally of the attachment device 20 is a holder 30, which may be formed integrally with the attachment device 20 or connected to a separately manufactured attachment device 20. The holder 30 has an adjustable receiving portion 31 which projects rearward beyond the holder 30 and is used to receive a rear limiting element 92. The length of the holder 31 can be adjusted and fixed by a nut 32 which can be tightened against the holder 30.

[0034] The holder 30 is attached to the front and rear regions 41, 42 of the main spring 40, which in the illustrated embodiment is assembled from three leaf springs 44, 45, 46. In the illustrated embodiment, the holder 30 is supported on the proximal spring 44 via a front force introduction region 410 and a rear force introduction region 420. Between the front force introduction region 410 and the holder 30, a front damping element 50 is arranged, which rests on a receptacle 910 for a front limiting element 91. Between the force introduction region 410 and the proximal spring 44, below the damper 51, which may be formed for example as an elastomer damper, a pivot axis 110 is formed, which extends substantially horizontally, substantially perpendicular to the plane of the drawing or orthogonally to the sagittal plane.

[0035] About this axis of rotation 110 the holder 30 can be tilted relative to the main spring 40, in particular the proximal spring 44. The front limiting element 91 and the rear limiting element 92 are guided around the distal or base spring 46 and have a bias caused by the deformation of the leaf springs 44, 45, 46 in the illustrated unloaded state of the prosthetic foot insert 10. All components of the prosthetic foot insert 10 are held together by this bias. In the region of the front limiting element 91, between the rear leaf spring 45 or the inner spring 45 and the distal spring 46, a contact element 48 is arranged, the position of which can be moved in the front-rear direction. The contact element 48 can be exchanged, for example, in order to determine the force introduction location between the inner spring 45 and the distal spring 46. The different force introduction points result in a different contraction behavior depending on the position in the front or rear direction. A contact element 47 is also disposed between the front end of the inner spring 45 and the front end of the distal spring 46 and is supported thereon in a displaceable or replaceable manner. By the material selection, size and position of the contact elements 47, 48 the spring characteristics of the prosthetic foot insert 10 can be adjusted.

[0036] In addition to this, a guide element 80 is arranged between the proximal spring 44 and the holder 30, which guide element is fixed, for example screwed, glued, welded, form-lockingly fixed or clamped, to the holder 30 in the rear region 42, i.e. the region located after the introduction of a force into the mounting device 20. The guide element 80 extends beyond the front force introduction region 410 to the front end region of the proximal spring 44 and is formed as a spring leaf in order to enable tilting of the holder 30 relative to the main spring and to enable rolling of the holder 30 on the upper surface of the proximal spring 44 in the region of the front force introduction region 410.

[0037] The limiting elements 91, 92 can in particular be formed as belts, ropes or cables, which can be formed as loops and can be guided around the upper surface of the holder or the underside of the base spring 47. It is also possible for the limiting elements 91, 92 to be telescopically stretchable sleeves or flexible, tensile-strong ropes, which are held taut between the receiving parts of the holder 30 and the base spring 47. The prosthetic foot insert 10 can be embedded in the foot cosmetic element 3 and can be replaceably attached thereto.

[0038] The limiting elements 91, 92 can be formed so that one or both of them can be adjusted, in particular so that they can be shortened or lengthened. Alternatively, the bias between one or both of the limiting elements 91, 92 and the holder 30 and / or the base spring 46 can be varied by inserts or spacer pieces. Alternatively, the bias can be varied by replacing the limiting elements 91, 92 with different lengths. In order to prevent the limiting elements 91, 92 from coming loose when the limiting elements 91, 92 are unloaded or unbiased, the limiting elements 91, 92 can be form-lockingly fixed in the respective receiving parts. For example, at the rear end of the base spring 46, a receiving part 93 is provided with a thread or device for fixing the limiting element 92. The receiving part 93 can simultaneously have a cushioning function.

[0039] In the event of a heel load exceeding that in the standing position, for example during heel strike, the three springs 44, 45, 46 of the base spring 40 contract, such that the holder 30 applies an axial force via the rear force introduction area 42 in the direction of the floor and compresses the main spring 44 in the rear area, thereby unloading the rear limiting element 92, whereas the front limiting element 91 remains in tension. In the further progression of the foot load, if a force is introduced substantially vertically into the attachment device 20 via the proximal component 2, a uniform compression in particular of the proximal spring 44 and the medial spring 45 takes place, whereby the two limiting elements 91, 92 are unstressed.

[0040] Then, when the proximal component is tilted forward, i.e. forward, within the range of walking forward, the rear end of the holder 30 lifts off the proximal spring 44, which creates a dissociation or gap between the rear force introduction area 420 and the proximal spring 44. The holder 30 is then fixed in the medial-lateral direction via the guide element 80 and is prevented from twisting relative to the main spring 40. By supporting the holder 30 in a tiltable or pivotable manner, rolling on the main spring 40 can be performed relatively easily without much resistance. As soon as the pivot angle increases and the distance between the rear end of the holder 30 and the rear end of the base spring 46 increases and the rear limiting element 92 becomes tense, the base spring 46 is additionally activated and provides an additional counterforce against further pivoting forward. The maximum pivoting distance of the holder 30 relative to the proximal spring 44 is thereby limited, so that it is possible to provide a switching activation of the individual springs 44, 45, 46 during the walking cycle. The limiting element 92 activates the limiting.

[0041] 2 shows a variation of the prosthetic foot insert 10 also having three springs 44, 45, 46, with the proximal spring 44 and the medial spring 45 arranged biconvexly relative to one another, thereby forming an elliptical or nearly elliptical space 400. A space 401 is also formed in the posterior region between the lower surface of the medial spring 46 and the upper surface of the distal spring 45 to allow for contraction during heel strike.

[0042] The variant according to Fig. 2 has in the front and rear regions of the holder 30 receiving compartments 910 and 940 formed as grooves for receiving the respective limiting elements 91, 92. The base spring 46 is likewise formed with receiving compartments 920, 930, which serve to protect the base spring 46 and at the same time prevent the respective limiting elements 91, 92 from unintentional movement. The receiving compartment 930 at the rear end of the base spring 46 has a through hole which prevents the limiting element 92 from escaping even when the load is released. The receiving compartment 930 is formed in the heel cushion 100, while the toe cushion 120 is arranged at the front end of the base spring 46. Between the springs, respectively replaceable or displaceable contact elements can be arranged, which in the illustrated embodiment are only indicated with the reference number 49 between the rear end of the proximal spring 44 and the inner spring 45. Between the holder 30 and the proximal spring 44, a damper element 52 as an elastomer damper can be arranged.

[0043] The front end of the holder 30 is connected to the spring 44 via a hinge, so that the holder 30 can pivot relative to the proximal spring 44, but cannot deviate vertically therefrom. The bearing body of the hinge is form-lockingly connected to the proximal spring 44 for receiving torsional forces, so that torsion about a vertical axis is not possible. However, tilting about a substantially horizontal pivot axis 110 perpendicular to the gait or longitudinal extension of the prosthetic foot insert is possible. The hinge can be attached in the rear region 42 of the main spring 40, for example by means of a spring leaf or spring element, or in the front region 41 by clamping or other form-locking fixing.

[0044] In Fig. 3 another variant of the invention is shown, the spring construction of which corresponds substantially to Fig. 1 or 2, with a difference being the attachment of the holder 30 to the main spring 40 via a guide element 80. Whereas in Fig. 1 the guide element 80 extends from the front end region of the proximal spring 44 to the rear end region of the holder 30, the illustrated embodiment comprises a folded or multi-part guide element 80, which is first fixed in the front region 41 to the proximal spring 44, for example via an elastomer damper 51 or a mounting element. The guide element 80 extends from the front region 41 to the rear region 42 of the proximal spring 44 and from there forward again, under a front limiting element 91 just before the front damper, where it is held on the underside of the holder 30 via a mounting element 61. The folded form of the guide element 80, which can be formed, for example, as a spring plate, makes it possible to perform a forward tilting movement about the front pivot axis 110 in the region of the front force introduction area 410 and also to enable a rearward tilting movement in the rear area 42 about the rear pivot axis 111 above the rear damper 52 in the rear force introduction area 420, which acts, for example, in the case of a rearward movement in the presence of an axial load, until the front limiting element 91 is effectively switched over by a corresponding movement and detensioning of the spring. Instead of the integral folded embodiment of the guide element, it is also possible for the guide element to be formed from two parts and to be connected in the rear rear area.

[0045] In figure 4 another variant of the invention is shown, in which a guide element 80 extends from the rear region 42 to the front region 41 of the holder 30 on the main spring 40, which is held via an attachment element 62, for example in the form of a clip or clamp, and is held there in a clamped manner or fixed via a front attachment element 61. In order to gently form the contact between the holder 30 and the spring 44 during walking, dampers 51, 52 can be arranged between the attachment elements 61, 62 and the proximal spring 44 or the holder 30. The limiting elements 91, 92 are formed as loops, the front loops being guided medially-laterally around the prosthetic foot insert 10 and the rear limiting element 92 being guided medially and / or laterally, and furthermore several limiting elements 92 can be arranged medially and / or laterally on the holder 30 and the base spring 47.

[0046] In Figures 5a-5c different loading phases of another embodiment of the prosthetic foot insert 10 are shown. Figure 5a shows the prosthetic foot insert 10 in the foot cosmetic element 3 in an unloaded state or in a relaxed standing position, with the holder 30 supported at its front end by a distal spring 46 via a dual spring assembly having a proximal spring 44 and an inner spring 45, in a substantially horizontal orientation.

[0047] Below the distal spring 46 is arranged the bottom spring 43, on which the heel cushion 100 and the toe cushion 120 are arranged. The distal spring 46 and the bottom spring 43 are attached to each other at the front end of the distal spring 46, approximately in the region of the toe cushion 120. The distal spring 46 can extend to the toe end or to the front end of the bottom spring 43. Between the upwardly bent distal spring 46 and the base spring 43 a contact element 47 is arranged, via which the force introduction point can be adjusted, in particular during heel loading.

[0048] By the bias of the two limiting elements 91, 92 formed as belts, the stiffness of the prosthetic foot insert 10 against tilting in the anterior-posterior direction can be adjusted: the greater the bias of the limiting elements 91, 92, the stiffer or more stable the prosthetic foot insert is.

[0049] In Fig. 5b the arrangement and behavior of the prosthetic foot insert 10 during high heel loading is shown diagrammatically. A load is applied to the rear part of the holder 30, pressing the rear end of the distal spring 46 in the direction of the rear end of the base spring 43. As the front end of the distal spring 46 is fixed in the toe region of the base spring 43, the distal spring is bent in the midfoot region via the contact element 47, which results in a three-point bending. Furthermore, in front of the contact element 47, a force acting vertically downwards is applied via the double springs 44, 45, based on the bias of the limiting element 91. In Fig. 5b, the limiting element 92 is fully de-stressed, but behind the holder 30 there is still a guide arranged on the distal spring 46 and the holder 30, which prevents the rear limiting element 92 from being able to detach from the holder 30.

[0050] During toe loading, which occurs for example during rolling after a so-called rollover, the load is applied to the front, front area of ​​the holder 30, which is supported via the two springs 44, 45 on the distal spring 46 and via the distal spring 46 on the base spring 43.

[0051] The contact element 47 defines a force introduction point which is modified by the displacement along the longitudinal extension of the spring.

[0052] The proximal spring 44 and the inner spring 45 can be moved towards each other, thereby reducing or minimizing the space 400 between the two springs. The rear end of the holder 30 is moved upwards, based on the pivotable bearing in the proximal spring 44, until the rear end contacts the rear limiting element 92. In this state, the rear end of the holder 30 lifts off the distal spring 46.

[0053] FIG. 6 shows another variant of the prosthetic foot insert 10 with a mounting element 80 in the form of a spring tongue fixed to the underside of the holder 30 by a screw 62 or another mounting element. The holder 30 is supported by the proximal spring 44 and the upper side of the guide element 80 via the cushion 53. When the toe is loaded, the holder tilts about an undefined pivot axis in the rest area of ​​the cushion 53 until the rear limiting element 92 prevents further pivoting relative to the proximal spring 44. The guide element 80 extends to the front end of the proximal spring 44, where it is held by a mounting element 61, e.g. a clasp, clip or belt. The distal spring 46 ends approximately at the same height as the proximal spring 44. The inner spring 45 extends further forward beyond the toe cushion 120. In the rear region, dampers 51, 52 are arranged between the holder 30 and the proximal spring 44 and between the proximal spring 44 and the inner spring 45 to damp the impulse when the spring or springs are lifted off the holder 51 upon contact. To allow the movement of the components away from each other, the dampers 51, 52 are preferably attached only on one side to the holder 30 or to one of the springs 44, 45. In case of highly elastic materials, the dampers 51, 52 can be glued to the components on both sides.

[0054] Figure 7 shows a variant of Figure 6 with a similar structure, but with a screw passing through all springs 44, 45, 46 instead of a clasp or clip as attachment element 61, which prevents the springs 44, 45, 46 from displacing along each other under load. Between the springs 44, 45, 46, cushions or dampers 54, 55, respectively, are arranged, and cushioning elements can also be arranged between the head of the screw 61 and the proximal spring 44, and between the nut and the distal spring 46. The clamping in the toe region superimposes a moment on the springs 44, 45, 46 during deformation, which shortens the free spring length. The clamping by the screw 61 prevents thrust movements and makes the prosthetic foot insert 10 overall stiffer than in the loose case, which allows the springs to displace along each other.

[0055] 8 shows another variant of the invention with a guide element 80 formed as a hinged housing for the holder 30, the front end of which can be pivoted about a pivot axis 110. The rear end of the holder 30 is limited by a rear limiting element 92 and by its maximum pivoting relative to the distal spring 46. The guide element 80 extends to the toe region and is arranged on the base spring 46 together with the distal spring via a mounting element 61. A damper 51 is arranged between the holder 30 and the guide element 80, which extends to the rear end of the holder 30, as well as another damper 52 between the guide element 80 and the rear end of the proximal spring 44.

[0056] Figure 9 shows a variant of figure 8, in which instead of a base spring a bottom guide element 88 is arranged to accommodate and guide the main spring 40. The guide element 80 and the bottom guide element 88 are connected to one another via a fastening element 61 in the region of the toe cushion 120, the guide element 80 having at its front end an extension tongue via which a resilient and spring-elastic bearing is realised for the bottom guide element 88.

[0057] Figure 10 shows an embodiment of the variant according to Figure 8 in which a damper 50 is arranged between the holder 30 and the mounting device 20, so that not only is the holder 30 pivotably supported relative to the proximal spring 44 about a pivot axis 110, but the mounting device 20 is also pivotable relative to the holder 30 about a pivot axis 110. The mounting device 20 is shown in three positions, the solid line indicates the basic position, the dotted line indicates a tilted forward position of the mounting device 20 and the dashed line indicates a lowered, tilted backward position of the mounting device 20.

[0058] Besides the form as a damper 50, an actuator can also be provided, which allows a motorized adjustment of the inclination and thus an adaptation, for example, to different heel heights. If the device is formed as a damper 50, a constant force or a constant moment can be provided for the downward or forward tilting to occur. A slow sinking or lifting allows the correct position, for example by closing a corresponding control valve and by locking the damper 50 formed as a hydraulic damper in the desired position.

[0059] Fig. 11 shows a variant of Fig. 6 with a holder having a shape on its underside that is approximately parallel to the shape of the upper surface of the proximal spring 44. The contact element 47 between the distal spring 46 and the inner spring 45 is arranged in the region of the front limiting element 91, the cushions 51, 52 in the rear region of the prosthetic foot insert are prevented from lateral displacement by the rear limiting element 92, and a guide at the rear end of the distal spring 46 prevents the cushions 51, 52 from displacing rearward. The guide element 80 extends from the rear end to the front end in the rear region 42 of the springs 44, 45, 46 and is fixed thereto by the screw 62. The springs 44, 45, 46 and the guide element 80 are clamped and held form-fittingly by the screw 62, so that a thrust moment is superimposed on the springs when they are deformed, which reduces the free spring length overall.

[0060] In the embodiment according to FIG. 11 as in all other embodiments, by attaching the limiting elements 91, 92, or at least one of the limiting elements 91, 92, to the holder 30 and to the distal spring 46 or to the heel cushion 100, respectively, it is possible to achieve stabilization against pronation and / or supination, since it is impossible for the limiting elements 91, 92 to be displaced relative to the holder 30 and / or the distal spring 46, and only compression is permitted upon corresponding axial load.

[0061] In the embodiment according to Fig. 11, the proximal spring 44 and the inner spring 45 are formed with a substantially parallel curve, which reduces the contraction space but allows a softer rolling movement overall. The distal spring 46 is curved away from the inner spring 45, which creates a gap and space between them that expands in the posterior direction, which almost reaches the front limiting element 91 or contact element 47.

[0062] FIG. 12 shows another variant similar to the embodiment of FIG. 6, but without the guide element and with a cushion 51 in the front region of the holder 30. In the lower region of the attachment device 20, a contact element 48 is arranged between the lower surface of the holder 30 and the upper surface of the proximal spring 44, the springs 44, 45, 46 being fixed to each other by a screw 42 and connected to the toe cushion 120. The positioning of the contact element 48 defines the position of the pressure point or the force introduction point. As long as there is a heel load and the toe is not on the ground, the rolling point of the heel determines the force introduction point. The rear limiting element 92 is released, the springs 44, 45, 46 in the heel region are compressed and moved relative to each other. The front limiting element 91 is tensioned and prevents the holder 30 from moving away from the proximal spring 44. As soon as the toe touches the ground, the front limiting element 91, e.g., belt, is released, allowing the distal spring 46 and the rear end of the holder 30 to move away from each other, tensioning the rear limiting element 92 to the adjusted maximum distance. The further forward the contact point between the holder 30 and the proximal spring 44, i.e., the further forward the positioning, the softer the axial flexibility needs to be adjusted.

[0063] Another variant of the invention is shown in FIG. 13, in which the spring structure substantially corresponds to that of FIG. 12. In addition to the limiting elements 91, 92, a functional cover 200 is arranged around the spring components and the holder. The functional cover 200 is formed like a sock and is used in addition to the foot cosmetic element 3. In the illustrated embodiment, the functional cover 200 does not surround the heel cushion 100 and the toe cushion 120, but it could also surround them. The functional cover 200 can be formed from a non-stretchable or high-strength material with a matching elastic modulus, and is used in particular to reduce friction and thus noise in the prosthetic foot. Additional belts or fastening elements 93, 94 can be used together with the functional cover 200, or the fastening elements 93, 94 can also be integrated into the functional cover 200, in order to adjust the elastic properties and the rolling and energy transfer properties of the prosthetic foot insert 10.

[0064] 14 shows a variant having a holder 30, at the front end of which a cylinder chamber 71 is formed or arranged for accommodating a movable piston 70. The piston 70 is supported by the proximal spring 44 via a piston rod 72. In addition to this, the holder 30 is connected at its rear end with the front end of the proximal spring 44 via a guide element 80.

[0065] In the front region, the guide element 80 is connected to the spring 44 via a fastening element 61. The inner spring 45 and the distal spring 46 are separately abutting and connected to one another via screws 62.

[0066] The holder 30 is supported on the proximal spring 44 via the contact element 49 so as to be pivotable about the pivot axis 110. During heel loading, e.g. heel strike, the piston 70 in the cylinder chamber 71 does not appear until the beginning of the stance phase when the prosthetic foot insert lands flat on the ground, so that no axial force is applied to the proximal spring 44 via the piston rod 72. As soon as the rolling movement progresses and the load on the toe increases, the piston 70 comes into contact with the upper boundary of the cylinder chamber and a compression force is applied to the spring via the piston rod 72. From a certain point in time, an axial force is thereby introduced into the main spring 40, preventing or making difficult any further movement in the forward direction or forward tilting, thereby providing the user with high stability from mid-stance onwards. The rolling and slight tilting around the zero position is made possible by the play that the piston 70 has in the chamber 71. A restoring force can be provided by the guide element 80.

[0067] 15 shows the position where, under high axial load, the piston 70 strikes the upper surface of the chamber 71, compressing the spring. The rear limiting element 92 is released, lifting the rear end of the guide element 80 off the top surface of the proximal spring 44.

[0068] FIG. 16 shows the prosthetic foot insert of FIGS. 14 and 15 with the holder 30 tilted against the walking direction, and the piston 70 contacts the underside of the cylinder chamber 71, preventing further pivoting against the clockwise direction and thus movement of the holder 30 or the front end of the holder 30 away from the proximal spring 44.

[0069] All embodiments of the present invention allow the prosthetic foot insert 10 to be made relatively flat, which basically makes it possible to use the prosthetic foot insert 10 together with additional prosthetic foot joints or to adapt it to patients with long transtibial stumps, e.g. amputation stumps. The small number of parts, which can be easily manufactured and do not require complex molding methods, facilitates on the one hand the manufacture and on the other hand a robust and reliable design, which can be adapted by an orthopaedic technician to the different needs and conditions of use of the respective user. The mechanical design of the prosthetic foot insert 10, which has parts that are not very mobile, requires no or only low maintenance costs, which allows it to be adapted to the individual and, in some cases, can be changed during the life of the use, nevertheless requiring only low service costs.

[0070] In most embodiments of the invention, three leaf springs are provided which can be divided into two functional pairs. The proximal and medial springs usually act as toe springs, whereas the medial and distal springs mainly act as heel springs. The distal spring is still connected at the end of the toe movement. In the unloaded state, the heel and toe are biased by the limiting element, as in normal standing loading. The holder is attached to the spring assembly via a guide element, usually the proximal spring. Through at least one contact element arranged between the holder and the proximal spring, the force introduction point and therefore the transition from heel loading to the stance phase and toe loading are adjusted. A second contact point in the area of ​​the physiological stability point in front of the attachment device has the function of defining the force introduction point during toe loading. By moving the contact points or contact elements between the respective springs, the spring stiffness of the entire system is changed without changing the mutual assignment of the individual springs and thus the overall structure of the prosthetic foot insert. When the prosthetic foot is subjected to normal load during standing, the axial forces are distributed evenly to both feet of the patient.

[0071] In that case, the spring bias is usually so large that the two limiting or posterior limiting elements are not yet released. In other words, the bias of the limiting or biasing elements is selected such that sufficient stability is provided via the prosthetic foot insert during standing to provide a sufficient sense of stability to the user.

[0072] During toe-loading, i.e., slight forward bending, the holder's ability to move about the pivot axis initiates a gentle rolling process, which in turn stores energy in the spring and allows for energy transfer from the heel spring to the toe-loading.

[0073] Additionally, the spring adaptation can provide a drop in mid-stance, thereby achieving uniform sinking and motion that matches natural gait motion. The energy stored in the spring during mid-stance is released during further gait progression, facilitating forward motion.

[0074] Especially during the foot strike phase after the swing phase, i.e. heel strike, the prosthetic foot insert provides a lot of spring deflection at the heel. Furthermore, the spring bias can be applied via a limiting element in the heel region. During toe loading at end stance, all three springs or all springs act together. The transfer of energy during rolling from heel strike to toe at end stance moves the user in the walking direction, since there is no upward vertical movement due to sinking during rollover. Thus, technically short prosthetic foot inserts are possible, where the user does not have the feeling of falling into a hole at end stance due to the unnatural early rolling and lowering of the body's center of gravity that occurs with a mechanically short foot. With the prosthetic foot insert, a uniform spring bias that causes a lift at end stance when the springs are released at the toe brings about a drop at mid stance.

[0075] Besides the position of the contact elements, the shape and dimensions of the contact elements are also crucial for the walking behavior and energy transfer: the narrower the contact elements and therefore the force introduction area, the more precise and accurate the behavior, the wider the contact elements or force introduction areas, the softer the walking sensation.

[0076] It is preferred that the spring is oriented perpendicular or nearly perpendicular to the load, so that in the case of a leaf spring the longitudinal extension is substantially perpendicular to the load direction, so that the material properties of the leaf spring are optimally utilized. The spring bias is advantageously selected so that no or only minimal deformation occurs during normal standing, so that the force introduction point is in a stable state and a quiet standing position is possible without excessively high stiffness. [Explanation of symbols]

[0077] 2. Proximal Component 3. Foot cosmetic elements 10 Prosthetic Foot Insert 20 Mounting device 30 Holder 40 Main spring 41 Anterior area 42 Posterior area 43 Base spring 44 Proximal Spring 45 Inner spring 46 Distal Spring 47 Contact Elements 48 Contact Elements 49 Contact Elements 50 Damper 51 Damper 52 Damper 53 Cushion 54 Cushion 55 Cushion 60 Plain bearing 61 Mounting elements 62 Screw 70 Piston 71 Cylinder 72 Piston rod 80 Guide Elements 88 Bottom Guide Element 91 Limiting factors 92 Limiting factors 100 heel cushion 110 Swivel Axis 111 Swivel axis 120 Toe cushion 200 Cover 400 space 401 Space 410 Force introduction area 420 Force introduction area 910 Storage unit 920 Storage unit 930 Storage unit 940 Storage unit

Claims

1. a. a proximal attachment device (20) for securing the prosthetic foot insert (10) to the proximal component (2) or to a patient; b. a holder (30) disposed distally of and connected to the mounting device (20); c. a main spring (40) extending into the toe region (11) and coupled to said holder (30), The holder (30) is supported on the main spring (40) so as to be tiltable in the sagittal plane, and a rear limiting element (92) for limiting the movement of the holder (30) in a direction away from the main spring (40) is disposed between the main spring (40) and the holder (30). A prosthetic foot insert comprising:

2. 2. The prosthetic foot insert according to claim 1, characterized in that the main spring (40) is formed as a spring consisting of at least one proximal spring (44) and at least one distal spring (45, 46).

3. 3. The prosthetic foot insert according to claim 2, characterized in that the proximal spring (44) and the distal spring (45, 46) are fixed to each other so as to form spaces (400, 401) spaced apart from each other.

4. 4. The prosthetic foot insert according to claim 2 or 3, characterized in that the proximal spring (44) and one or both of the distal springs (45, 46) are biconvexly shaped and oriented relative to one another.

5. 5. The prosthetic foot insert according to claim 1, wherein a guide element (80) is attached to the front region (41) or the rear region (42) of the main spring (40) and extends in opposite directions, and the holder (30) is tiltably supported via the guide element (80).

6. 6. The prosthetic foot insert according to claim 5, characterized in that a front limiting element (91) is arranged between the guide element (80) and the holder (30) or the main spring (40), the front limiting element limiting the movement of the front end of the holder (30) or the main spring (40) away from the guide element (80) during heel loading.

7. 7. Prosthetic foot insert according to claim 5 or 6, characterized in that the main spring (40) and the guide element (80) are formed as leaf springs.

8. 8. Prosthetic foot insert according to claim 1, wherein the restricting elements (91, 92) are designed to be tensile strong and flexible.

9. The prosthetic foot insert according to any one of the preceding claims, characterized in that a toe cushion (120) and / or a heel cushion (100) are attached to the main spring (40).

10. The prosthetic foot insert according to any one of claims 1 to 9, characterized in that the holder (30) is supported on the main spring (40) via a spring tongue, a hinge or at least one spacer element.

11. The prosthetic foot insert according to any one of claims 1 to 10, characterized in that the holder (30) introduces forces into the main spring (40) via a front force introduction area (410) in front of the attachment device (20) and via a rear force introduction area (420) behind the attachment device (20).

12. 12. The prosthetic foot insert according to claim 11, characterized in that at least one of the front and rear force introduction areas (410, 420) is movably or exchangeably supported on the holder (30) or on the main spring (40).

13. 13. Prosthetic foot insert according to any one of the preceding claims, characterized in that at least one damping device (51, 52) is arranged between the holder (30) and the main spring (40).

14. The prosthetic foot insert according to any one of the preceding claims, characterized in that the holder (30) is supported on the main spring (40) at an adjustable proximal-distal distance.

15. 15. The prosthetic foot insert according to any one of the preceding claims, characterized in that in the unloaded state, the main spring (40) is elastically biased against the guide element (80) by a limiting element (91, 92).

16. 16. The prosthetic foot insert according to claim 1, wherein the mounting device (20) is displaceably and / or articulatedly supported in the holder (30).

17. 16. Prosthetic foot insert according to claim 15, characterized in that a damper (50) is arranged between the mounting device (20) and the holder (30).

18. 18. Prosthetic foot insert according to any one of claims 2 to 17, characterized in that exchangeable and / or displaceable supported contact elements (47, 48, 49) are arranged between the proximal spring (44) and the inner spring (45) and / or between the inner spring (45) and the distal spring (46).

19. The prosthetic foot insert according to any one of claims 1 to 18, characterized in that the holder (30) is supported by the main spring (40) so as to be tiltable on a surface whose position can be changed in the sagittal plane.

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