Patent Publication Number: US-2022218501-A1

Title: Sensor support for arranging on a prosthesis

Description:
The invention relates to a sensor support for arranging on a prosthesis according to the preamble of claim  1 . 
     Modern prostheses are often equipped with sensors. Sensors are typically arranged directly inside a prosthesis and are permanently fitted therein. For example, multiple pressure sensors are fitted inside the prosthetic sole of a prosthetic foot. The prosthesis often includes several stimulators as well. These stimulators are electrically connected to multiple pressure sensors. The stimulators are thus controlled and excited by the pressure sensors, and act on the patient&#39;s remaining extremity through the skin on. In this way, the stimulators enable the prosthesis user to perceive a pressure on the pressure sensors and thus “feel” the pressure on the prosthetic sole. Apparatuses of such kind are disclosed in WO 98/25552 A1 for example. 
     The disadvantage of this known solution is that not only are prosthesis systems of such kind very expensive, the adaptation phase and familiarisation phase in which the prosthesis user gets used to the prosthesis take a great deal of time. Furthermore, they also entail multiple appointments with a specialist doctor and/or orthopaedist. There, the positions of the stimulators and pressure sensors must be adjusted several times, which can be difficult if they are already fitted permanently. 
     It is the object of the present invention, to remedy one or more drawbacks of the related art. In particular, a sensor support is to be produced which can be attached to existing prostheses easily without changing them structurally. In the fitted state on prosthesis, the sensor support should function reliably, but on the other hand it should also be easy to remove and fitted again in another prosthesis, for example. 
     This object is solved by the features of the independent claim. Advantageous further developments are presented in the description, the figures, the description of the drawing, and in the dependent claims. 
     A sensor support according to the invention for arranging on a prosthesis comprises a main part for receiving sensors, wherein said main part has a sensor section with sensors, and the main part has a holding section for holding the main part on a prosthesis part. The main part includes a knitted fabric tube. The holding section has a first knitted structure, which allows a secure hold of the main part on the prosthesis part. The sensor section has a different knitted structure which allows a secure positioning of the sensors relative to the prosthesis part. 
     The present sensor support can be arranged on any prosthesis, which accordingly is not required to have any sensors itself and may therefore be of simpler construction. In this arrangement, not only are the sensors positioned fixedly in the main part, but the sensors are also fixed in a previously defined position on the prosthesis part with the aid of the different knitted structures on the sensor section and the holding section of the main part. The knitted structure on the adhesive section prevents creases from forming in the fabric tube. Creasing might result in incorrect positioning of the sensors on the prosthesis. The knitted structure on the sensor section knitted relatively more sturdily and thus minimises the mechanical load on the sensor when the prosthesis is in use, thereby prolonging its service life, and the prosthesis itself is exposed to less impact loading (damping). 
     The novel sensor support enables the prosthesis user to “feel” the prosthetic motion/rolling motion of the prosthetic foot, as with conventional prostheses with built-in sensors, but it also allows easy removability of the sensors together with the sensor support, simple cleaning of the prosthesis, thus improving daily interaction with the prosthesis. 
     Even difficult movements, such as moving/walking on steep terrain with an artificial foot, can be learned using the novel sensor support. Since this sensor support can be arranged on any prosthesis of any kind, the prosthesis user does not have to change the prosthesis if he/she wishes to use a “feeling” prosthesis. Since replacing a prosthesis is highly uncomfortable for prosthesis user, because the prosthesis shaft must be adapted to prosthesis user&#39;s remaining anatomy, the invention is extremely advantageous. 
     In particular, the sensor support is suitable for arrangement on an artificial hand or an artificial foot. These are widely used prosthesis types, which are thus able to be improved with the sensor support as described herein. 
     The holding section preferably includes a second knitted structure in addition to its first knitted structure. The knitted structures on the holding section enable a secure hold on the prosthesis part. They are arranged in various positions on the main part, so the main part cooperates with the prosthesis part with stable holding effect in more than one position. 
     The second knitted structure is preferably designed differently from the first knitted structure. Different knitted structures have different stretch characteristics, enabling the sensor support to be arranged reliably on the prosthesis part. 
     In particular, the second knitted structure is of dimensionally stable design in order to enclose a prosthesis part. A dimensionally stable knitted structure creates an improved hold on the prosthesis part, as the knitted structure is connected to the prosthesis part in force-fitting manner. For example, the dimensionally stable knitted structure is arranged on the area of the sensor support which cooperates with the heel of an artificial foot. The affords the prosthesis user the improved “feel” of a sequence of movements, when walking or running, for example, thereby increasing the prosthesis user&#39;s confidence in the prosthesis and consequently their stability when walking. 
     More preferably, besides its first knitted structure the holding section also includes a third knitted structure, which is designed differently from both the first knitted structure and the second knitted structure. This serves to further improve the holding properties of the sensor support on the prosthesis by preventing the formation of creases in the knitted fabric tube. 
     In particular, the third knitted structure is of elastic construction. The knitted fabric tube may be pre-tensioned and may be stretched over the prosthesis part easily with the aid of the elastic third knitted structure. 
     Preferably, the first knitted structure of the holding section has a first denier, and the second knitted structure of the holding section has a second denier auf. The different knitted structures described here have different functionalities, which can be adjusted on the one hand through the knitted structure itself, but also using the different deniers. The different functionalities of the knitted structure are advantageous in various sections of the prosthesis. The holding properties of identical knitted structures may be improved with the different deniers. For example, a diamond-shaped knitted structure is advantageous, because such structures have favourable stretch characteristics. In particular, the denier of the first knitted structure is in a range between 0.1 mm and 0.6 mm, and is advantageously equal to 0.3 mm. In particular, the denier of the second knitted structure is in a range between 0.5 mm and 1.5 mm, and is advantageously equal to 1 mm. 
     The third knitted structure of the holding section preferably has a third denier. A third knitted structure with a third denier increases the flexibility of the range of applications for the sensor support. 
     In particular, the denier of the third knitted structure is in a range between 0.3 mm and 0.9 mm, and is advantageously equal to 0.6 mm. 
     More preferably, the knitted structure of the sensor section has denier which is different from the first denier of the holding section. In this way, the properties of the knitted structure that are specific to the sensor section are improved. For example, the denier of the knitted structure of the sensor section is thicker than the denier on the holding section, and so the sensors in the sensor section are protected from undesirable mechanical loads. In particular, the denier of the knitted structure of the sensor section is in a range between 0.6 mm and 1.5 mm, and is advantageously equal to 0.8 mm. 
     Preferably, at least one of the knitted structures is made from a resistant synthetic fibre. Synthetic fibres are durable and robust materials which can be worked in a knitting procedure. For example, a synthetic fibre made from nylon or polyester or materials with comparable properties is used. These serve to prevent the knitted fabric tube from becoming stretched or worn in selected areas. Particularly in the area of a prosthetic sole of an artificial foot, it is particularly important to prevent stretching and compression, in order to protect the sensors from damage by tensile forces. 
     More preferably, the sensor section has a multilayer construction and has one sensor layer in which the sensors are embedded. The sensor layer enables the sensors to be arranged in the sensor support in structured manner, which also allows provision to be made for the prosthesis user&#39;s individual needs. The multilayer structure of the sensor section results in improved protection of the sensor and at the same time contributes to the damping effect between the prosthesis and its surroundings (e.g., the ground or an inner shoe). 
     As is generally known, the sensors preferably comprise at least one pressure sensor. The at least one pressure sensor is designed for the purpose of recording pressures that normally act directly on the prosthesis and converting them into an electrical signal. 
     The electrical signal is then forwarded. The at least one pressure sensor functions piezoelectrically, for example. 
     Alternatively or additionally, the sensors comprise at least one force sensor. The force sensor is designed for the purpose of recording forces that normally act directly on the prosthesis and converting them into an electrical signal, which is then forwarded. A strain gauge is used as a force sensor, for example, because it is lightweight and can be arranged in the sensor layer without taking up much space. Besides compressive forces, force sensors are also designed to measure shearing forces. 
     An outer protective layer which is farthest from a prosthesis part when in use is preferably provided on the sensor section in addition to the knitted structure. The outer protective layer protects the sensor layer from unwanted mechanical loads, which can lead to the formation of creases in the sensor layer, for example. Consequently, not only can the sensor support be arranged directly on the prosthesis, it can also be used with the prosthesis inside an item of clothing, such as a shoe or glove, which might lead to the formation of creases on the sensor layer without this improved arrangement. In addition, this outer protective layer prolongs the service life of the sensor layer if the user walks on the ground or a floor without additional protective arrangements, for example. 
     Preferably, an inner protective layer is provided which is closest to a prosthesis part. The inner protective layer is designed for purpose of protecting the sensor layer mechanically from the inside, for example when the sensor support is stretched over the prosthesis. The stretching of the sensor support over the prosthesis may engender stretching forces which are absorbed by the inner protective layer and thus prevented from acting on the sensor layer. 
     More preferably, the outer protective layer is designed to suppress slipping at least in one direction. This prevents the outer protective layer from slipping on the ground or against an inner shoe, which in turn also prevents the sensor layer from slipping out of position in the sensor support. Synthetic leathers such as Alcantara may be used as the outer protective layer. The surface of the outer protective layer is designed to suppress slipping, for example. 
     In particular, at least a section of the outer protective layer, or the entire layer, is manufactured from an anti-slip material. An anti-slip material prevents the sensor support from slipping when the prosthesis is moved while it is located together with the sensor support in an item of clothing such as a shoe. In this situation, the anti-slip material interacts frictionally with the material of the item of clothing. 
     However, the anti-slip material may also be applied as a coating on a support material. In this case, the support material may be dimensionally stable and only the coating may be designed to suppress slipping. For example, a synthetic leather may be used as support material, covered with a coating of silicone or similar materials. Silicone can be applied easily and over large expanses of a support material and has strong adhesive stability, thereby preventing the coating from being worn off too quickly. 
     Alternatively or additionally, at least a section of the outer protective layer is made from a slip-favouring material. A slip-favouring material enables the outer protective layer to slip readily at least in one direction, thereby making it easier to arranged the sensor support inside an item of clothing, for example. In this arrangement, the slip-favouring material interacts with the item of clothing in a way that favours slipping (at least in one direction). 
     In particular, the outer protective layer is designed to favour slipping at least in one direction. This simplifies the task of arranging the sensor support inside an item of clothing and prevents the formation of creases on the sensor support. The slip-favouring material may also be applied to support material as a coating. In this case, the support material may be dimensionally stable and only the coating may be designed to favour slipping. For example, a synthetic leather may be used as support material, covered with a coating of vinyl, such as a vinyl film, or similar materials. A vinyl film can be applied easily and over large expanses of a support material and has strong adhesive stability, thereby preventing the coating from being worn off too quickly. 
     The outer protective layer preferably has a profile structure in order to enhance its anti-slip or slip-favouring property. A profile structure such as is described herein is understood to be a structured arrangement of materials having different properties which are arranged at a structured distance from each other and interact with each other to improve the anti-slip properties in one direction or the slip-favouring property in another direction of the sensor support. This may be a smooth, fur-like structure, for example. 
     Alternatively or additionally, the inner protective layer is designed to inhibit slipping at least in one direction. This prevents the inner protective layer from slipping out of position and therewith also prevents the sensor layer from slipping in the sensor support. The anti-slip material may be applied to a support material as a coating. In this arrangement, the support material may be dimensionally stable and the coating may be anti-slip. As described previously, for example, a support material made of synthetic leather coated with silicone may be used. 
     The inner protective layer is preferably designed to be anti-slip at least in one direction. This serves to prevent the inner protective layer from slipping on the prosthesis and thus also stops the sensor layer from slipping out of position in the sensor support. 
     In particular, at least a section of the inner protective layer is made from an anti-slip material. An anti-slip material prevents the sensor support from slipping out of position while the prosthesis is in use. The anti-slip material interacts frictionally with the material of the prosthesis. 
     Alternatively or additionally, at least a section of the inner protective layer is made from a slip-favouring material. A slip-favouring material enables the sensor support to be pulled over the prosthesis more easily. In such a structure, the slip-favouring material interacts with the prosthesis in sliding manner at least in one direction. 
     In particular, the inner protective layer is designed to favour slipping at least in one direction. This makes it easier to pull the sensor support over the prosthesis and prevents the formation of creases in the sensor support. The slip-favouring material may be applied to support material as a coating. In this arrangement, the support material may be dimensionally stable and the coating may be designed to favour slipping. As described previously, for example, a synthetic leather coated with vinyl may be used as the support material. 
     The inner protective layer preferably has a profile structure for enhancing its anti-slip or slip-favouring property. In this arrangement, the profile structure of the inner protective layer interacts with the prosthesis to promote sliding in one direction and interacts with the prosthesis frictionally in another direction. 
     Alternatively or additionally, the inner protective layer is designed to inhibit slipping at least in one direction. This prevents the inner protective layer from slipping out of position which in turn stops the sensor layer in the sensor support from slipping out of position. 
     In particular, as described herein the profile structure is embossed, which has the effect of further amplifying the properties of slip stability in the sensor section without making it more difficult to arrange the sensor support on an item of clothing. 
     The sensor layer is preferably embedded between the outer protective layer and the inner protective layer, so that any formation of creases in the sensor layer due to mechanical load is prevented. 
     In particular, the sensor layer is embedded separably between the outer protective layer and the inner protective layer in such manner that is can be replaced. This makes it possible to clean the sensor support without involving the sensors themselves in the cleaning operation. 
     More preferably, the sensor layer is arranged in the sensor section with material bonding. In this arrangement, a first side of the sensor layer is bonded to the sensor section adhesively, for example, so that potential shearing forces can be neutralised through the outer protective layer or the inner protective layer and are not transferred to the sensor layer. 
     Preferably, a control apparatus is provided and is connected electrically to the sensors. The control device receives the electrical signals generated by the sensors and is able to process them further. The sensors are connected to the control apparatus via electrical wires. The electrical wires may either be separate wires or they may be electrically conductive threads which have been worked into one of the knitted structures. 
     More preferably, the control apparatus is connected separably to the sensors of the sensor layer. For this purpose, the control apparatus may include a connection section on which the electrical wires are arranged so as to be detachable or separable. The control apparatus may optionally include various control programs, which may be adapted to reflect the structural arrangement of the sensors in the sensor layer, for example. Additionally, a sensor layer may be operated with different control apparatuses. The use of a sensor layer according to the invention in or on a sensor support according to the invention may be conceivable for various control apparatuses, and accordingly the sensor layer and/or the sensor support can be combined as a module with a range of modular control apparatuses. 
     The control apparatus may preferably be attachable to the prosthesis part. In this way, the control apparatus may be arranged on the prosthesis part or the prosthesis separately from the sensor support. The prosthesis part is the prosthesis shaft, for example, with which a firm attachment of the control apparatus can be created. This embodiment and those described hereinafter are also inventive and have industrial applicability independently of the other features of the sensor support. 
     The control apparatus is preferably attachable to the prosthesis part in such manner that it can be separated again. In this way, the control apparatus is held securely and the replacement of the control apparatus is made simpler for the prosthesis user. 
     The control apparatus is preferably attachable to the prosthesis part by means of a magnetic holder. The separable attachment of the control apparatus is further improved thereby. 
     Further advantages, features and details of the invention may be discerned from the following description, in which the invention is described with reference to the drawing and exemplary embodiments. Enumerations such as first, second, third or similar serve solely to identify the components. 
     The list of reference numerals is an integral part of the disclosure, as are the technical content of the claims and figures. 
     The descriptions of the figures are interrelated and unified. The same reference numerals denote identical components, reference numerals with different indices indicate functionally equivalent or similar components. 
     Document US 2016/206242 A1 discloses a sensor apparatus in a flexible and stretchable item of clothing, in which the sensors arranged therein capture physiological parameters of the skin or fabric covered by the item of clothing. The sensors arranged in the item of clothing may also capture parameters such as force or pressure exerted on or against a fabric or an area of skin below it. The sensor apparatus is equipped with pressure sensors and wires which are made from conductive fabric material and are worked directly into the item of clothing. 
     The object of US 2016/206242 A1 may appear to be a comparable sensor support, which is the reason for which the abovementioned document is cited here. However, there is no link between this known document and the statement of the problem, or the solution to the problem, that would motivate the person skilled in the art to make use of the teaching of this document, because the object of said document is entirely unrelated to the field of prosthetics. 
    
    
     
       IN THE DRAWING 
         FIG. 1  is a perspective view of a sensor support according to the invention, 
         FIG. 2  is a top view of a sensor layer of the sensor support of  FIG. 1 , 
         FIG. 3  shows the sensor layer of  FIG. 2  in the sensor section of the sensor support of  FIG. 1  along cross sectional line III, 
         FIG. 4  is a top view of an inner protective layer of the sensor section in the sensor support of  FIG. 1 , 
         FIG. 5  is a top view of an outer protective layer of the sensor section in the sensor support of  FIG. 1 , 
         FIG. 6  is a side view of the sensor support of  FIG. 1  with a control apparatus, and 
         FIG. 7  is a perspective view of the sensor support of  FIG. 1  with a control apparatus on a prosthesis. 
     
    
    
       FIG. 1  shows the sensor support  10  for arrangement on a prosthesis or a prosthesis part, wherein the prosthesis is for example an artificial foot. The sensor support  10  comprises a main part  20 , consisting of a knitted fabric tube  21  which is closed at one end (the front) of the tube and has a fabric tube opening  22  at an end of the tube opposite the closed end (the rear). The main part  20  is equipped with a sensor section  25  having sensors  15  (only shown symbolically here) and a holding section  30  with a first knitted structure  32 , which allows a secure hold of the main part  20  on the prosthesis part. The sensor section  25  has a knitted structure  27  which is different from the first knitted structure  32 , and which allows a secure positioning of the sensors  15  relative to the prosthesis part. A sensor layer  28  in which the sensors  15  are disposed in a structured and systematic way is arranged in the sensor section  25 . The knitted structure  27  is made from a durable synthetic fibre, whose denier is designed to ensure long-term protection of the sensors  15 . The first knitted structure  32  of the holding section has a denier which is different from the denier of the knitted structure  27  of the sensor section. 
       FIG. 2  shows the sensor layer  28  arranged in the sensor section  25  of the sensor support  10 . In this exemplary embodiment, the sensor layer  28  has the form of the sole of a foot. In this arrangement, the sensors  15  are disposed in different positions of the sensor layer  28 . Four sensors  15  are represented, wherein one sensor  15   a  is arranged in the heel area, two sensors  15   b  and  15   c  are arranged in the area of the ball of the foot, and one sensor  15   d  is arranged on the foot sole in the area of the toes. The sensors  15  are held in the sensor section with the aid of the knitted structure  27 . The denier of the knitted structure  27  has a value of about 0.8 mm. The sensors  15  are pressure sensors and/or force sensors which generate an electrical signal proportional to a pressure force when the pressure force is applied. The sensors  15  are connected to an electrical wire (see  FIG. 6 ) with which the electrical signal can be transported of the sensor layer  28 . 
       FIG. 3  shows the sensor section  25 , which has a multilayer structure. The sensor layer  28  with the sensors  15  embedded therein has an inner protective layer  26  on one side and an outer protective layer  29  on the opposite side. The two protective layers  26  and  29  protect the sensor layer  28  which is positioned between them, so that formation of creases in the sensor layer  28  may be prevented. At least the periphery of the sensor layer  28  is bonded adhesively to the outer protective layer  29 . 
       FIG. 4  shows the inner protective layer  26  of the sensor section  25 . In the use case, this inner protective layer  26  faces towards a leg prosthesis and is therefore in contact with the prosthesis part. A portion of the inner protective layer  26  is made from an anti-slip material  36 , which prevents the inner layer  26  from slipping out of position in a first direction  37 . In the case of a foot sole, this anti-slip Material  36  is arranged in the heel area, for example. A portion of the inner protective layer  26  is made from a slip-favouring material  38 , which improves slipping of the inner protective layer  26  in a second direction  39 . In such an arrangement, the first direction  37  may ideally extend in the opposite direction to the second direction  39 . In the case of a foot sole, this slip-favouring material  38  is arranged in the region of the ball of the foot, for example. The slip-favouring material  38  is constructed as a multipart profile structure  40 , wherein the parts thereof are at a structured, functional distance from each other. For example, the anti-slip material and the slip-favouring material are made from the same material which exhibits the same property in different directions. 
       FIG. 5  shows the outer protective layer  29  of the sensor section  25 . In the use case, this outer protective layer  29  faces away from the prosthesis and is therefore in contact with the ground on which the prosthesis is supported in the use case. A portion of the outer protective layer  29  is made from an anti-slip material  42 , which prevents the outer layer  29  from slipping on the ground in a first direction  43 . In the case of a foot sole, this anti-slip Material  42  is arranged in the region of the ball of the foot, for example. A portion of the outer protective layer  29  is made from a slip-favouring material  44 , which improves slipping of the outer protective layer  29  in a second direction  45 . In such an arrangement, the first direction  43  may ideally extend in the opposite direction to the second direction  45 . In the case of a foot sole, this slip-favouring material  44  is arranged in the heel region, for example. The anti-slip material  42  is constructed as a multipart profile structure  46 , wherein the parts thereof are at a structured, functional distance from each other. 
     For example, the anti-slip material and the slip-favouring material are made from the same material which exhibits the same property in different directions. 
       FIG. 6  shows the sensor support  10 , which in this case is additionally connected electrically to a control apparatus  50 . The main part  20  comprises the fabric tube  21  with a fabric tube opening  22 . The main part  20  has a holding section  30  which has a second knitted structure  33  besides it first knitted structure  32 , wherein the two are constructed differently. The denier of the first knitted structure  32  has a value of about 0.3 mm. The second knitted structure  33  is dimensionally stable and comprises the heel part of an artificial foot arranged in the fabric tube  21  in the use case. The denier of the second knitted structure  33  has a value of about 1 mm. The holding section further has a third knitted structure  34 , which is of elastic construction and has denier value about 0.6 mm. The knitted structures  33 ,  33 ,  34  are knitted with synthetic fibre strands. The sensor section  25  comprises the sensors  15 , which are connected electrically to the control apparatus  50 . For this purpose, each sensor  15  is connected to an electrical wire  16 , so that each sensor  15  is connected to the control apparatus  50  to enable the exchange of electrical signals. The electrical signals are generated when an external pressure force is detected at the respective sensor  15 , and are then forwarded by said sensor  15  to the control apparatus  50 , where they are processed further. The electrical wires  16  initially run inside the sensor layer  26 , they then exit the sensor layer  26  and run along the fabric tubes  21  towards the fabric tube opening  22 . The fabric tube  21  includes a connecting section  23  (interface) in the area of the fabric tube opening  22 . An interface  48  is arranged on the connecting section  23 , at which interface the electrical wires  16  are connected separably to the control apparatus  50 . The control apparatus  50  is arranged on a conductive strip  49  (ribbon conductor) which contains electrical wires. The electrical wires of the conductive strip  49  connect the control apparatus  50  to the interface  48  so that the electrical signals from the sensors  15  can be exchanged with the control apparatus  50 . The conductive strip  49  is separable from the interface  48 , which means the control apparatus  50  is connected separably to the sensors  15 . 
       FIG. 7  shows the sensor support  10  on an artificial foot  61  of a prosthesis  60 . The artificial foot  61  is connected mechanically to a prosthesis shaft—in a manner known per se—by a connecting element  62 . When the artificial foot  61  is arranged in the sensor support  10 , it is inserted in the fabric tube  21  and held in place in a force-fit by the knitted structures  32 ,  33 ,  34  of the holding section  30 . The sole of the artificial foot  61  lies flush against the sole section  25  of the sensor support  10 . Accordingly, when in use the sole of the artificial foot  61  rests indirectly on the sensors  15  of the sensor support. The control apparatus  50  is attached separably to the connecting element  63  of the prosthesis  60  by means of a magnetic holder  55 . 
     The magnetic holder  55  enables the control apparatus  50  to become detached from the connecting element  63  relatively easily and non-destructively, if a user trips inadvertently somewhere, for example. 
     The control apparatus  50  is connected electrically to stimulators  65 , which are or can be arranged on a prosthesis shaft  62  of the prosthesis  60 . In this way, it is guaranteed that the electrical signals from the sensors  15  are processed in the control apparatus  50  and can be used to excited the respective stimulators  65 . 
     LIST OF REFERENCE NUMERALS s 
     
         
           10  Sensor support 
           15  Sensors 
           16  Electrical wires for  15   
           20  Main part 
           21  Fabric tube 
           22  Fabric tube opening 
           23  Connecting section 
           25  Sensor section 
           26  Inner protective layer 
           27  Knitted structure from  25   
           28  Sensor layer 
           29  Outer protective layer 
           30  Holding section 
           32  First knitted structure from  30   
           33  Second knitted structure from  30   
           34  Third knitted structure from  30   
           36  Anti-slip Material 
           37  First direction 
           38  Slip-favouring material 
           39  Second direction 
           40  Profile structure from  26   
           42  Anti-slip Material 
           43  First direction 
           44  Slip-favouring material 
           45  Second direction 
           46  Profile structure from  29   
           48  Interface 
           49  Conductive strip 
           50  Control apparatus 
           55 Magnetic holder 
           60  Prosthesis 
           61  Artificial foot 
           62  Prosthesis shaft 
           63  Connecting element 
           65  Stimulators