Patent Publication Number: US-2023142491-A1

Title: Prosthesis cosmetic element and method for producing a molded part

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a national phase application of International Application No. PCT/EP2021/058471, filed 31 Mar. 2021, which claims the benefit of German Patent Application No. 10 2020 109 336.5, filed 3 Apr. 2020, the disclosures of which are incorporated herein, in their entireties, by this reference. 
    
    
     TECHNICAL FIELD 
     The invention relates to a prosthesis cosmetic with a base body made of a foam material and with a cavity formed in the base body for receiving a prosthesis component, the base body having an outer side facing away from the prosthesis component and an inner side delimiting the cavity. The invention also relates to a method for producing a molded part, in particular a prosthesis cosmetic, from a foam material with a cavity formed in the molded part for receiving a component, in particular a prosthesis component, in which method a tool core is introduced into a mold cavity of a molding tool and the mold cavity is filled with foam. 
     BACKGROUND 
     Prosthesis cosmetics are used to cover a prosthesis component, among other things with the aim of achieving the most natural appearance possible for the replaced limb, and for protecting the prosthesis component from any external influences. In addition, prosthesis cosmetics can protect the surroundings from direct contact with the prosthesis component, by making available a padding for the prosthesis component. 
     The direct manufacture of individual prosthesis cosmetics in a primary forming method is highly complex, since a mold first has to be produced which is adapted to the particular user. The usual procedure when producing a prosthesis cosmetic for a specific prosthesis component entails adapting a base body, which has a cavity for receiving the prosthesis component, to the particular patient by removal of material. As a rule, it is sought to produce the prosthesis component with a shape that corresponds to the intact side. The base body is generally made of a light, voluminous material, for example a foam material, which is processed by the relevant orthopedic technician. The shape of the outer contour is worked by grinding or by other cutting methods. 
     Processing the base body made of a foam material using grinding machines can lead to the foam catching in the grinding machine and tearing. This can lead to injuries to the person processing the base body and to destruction of the product. During the foaming process, a closed or almost closed surface, what is called the integral skin, is formed on the surface of the base body. A structural part or component arranged within the cavity generally executes a movement relative to the inner surface, which can lead to development of noise or to abrasion at the surface of the component that is received. 
     SUMMARY 
     The object of the present invention is to make available a prosthesis cosmetic and a method for producing a molded body from a foam material, with which the disadvantages of the prior art are avoided. 
     According to the invention, this object is achieved by a prosthesis cosmetic having the features of the main claim and by a method having the features of the additional independent claim. Advantageous embodiments and developments of the invention are disclosed in the subclaims, the description and the figures. 
     In the prosthesis cosmetic with a base body made of a foam material and with a cavity formed in the base body for receiving a prosthesis component, the base body having an outer side facing away from the prosthesis component and an inner side delimiting the cavity, provision is made that a textile is secured to the inner side of the base body. The dimensional stability of the entire prosthesis cosmetic is improved by the textile, in particular the foamed textile, secured to the inner side of the base body, which textile in one embodiment lines the cavity at least in regions. 
     In addition, the textile protects against unwanted removal of material during the processing of the base body, in particular if the base body has to be ground down to a small material thickness. The textile also improves work safety during the production of prosthesis cosmetics and ensures that there are fewer rejects. The textile also serves as a reinforcement, which greatly increases the durability of the prosthesis cosmetic. The finished molded body is more durable and no longer tears so easily when subjected to tensile loads. In addition, the arrangement of a textile on the inner side results in less noise being generated during the use of the prosthesis cosmetic, since the integral skin which is otherwise present at these points, and which is created on the inner surface or inner side of the base body on account of the temperature difference between the tool and the foam material introduced, is replaced. 
     The entire inner side of the cavity can be covered with a textile, as a result of which the dimensional stability of the prosthesis cosmetic is increased overall and the processability of the base body can be made easier when forming the desired outer contour. 
     In a further development of the invention, the textile is foamed into the base body and is thus an integral part of the base body. It is thereby possible to position the textile in conjunction with the formation of the cavity and to integrate it into the base body without a further work step during the foaming of the mold. The textile or the textile surface is directly back-molded or overmolded with the foam such that a textile inner coating is created in the three-dimensional cavity. The textile is applied to the tool and mechanically anchored in the foaming process. Subsequent gluing-in of a textile is therefore avoided, as also is the formation of the integral skin on the inner side. By virtue of the integral manufacture of the textile reinforcement together with the formation of the cavity, it is possible to arrange the textile over the entire surface area on the inner side, even with complex three-dimensional shapes of the cavity. The textile follows the outer contour of the tool core almost perfectly on account of the pressure that is exerted on the tool core by the foam material during the foaming, which is possible only with simple geometries when the textile is subsequently glued on. In addition, the manufacture of the base body is made easier, since the tool core can be molded directly from the component to be received, or from the prosthesis component to be received, without dimensional allowance. 
     The textile can be designed as a tube, wherein the tube can be designed in one piece with a closed cross section. In a variant, the tube is produced from a flat basic blank, for example by sewing side edges facing away from each other, after they have been placed on each other or over each other. Other connection techniques for forming a tube or a tubular molded body are also possible, for example gluing or welding. At one end, the tube can have an insertion opening for a tool core which forms the cavity in the base body. The tube is pulled onto the tool core before the mold is filled with foam, such that a textile reinforcement is created which at the same time provides a textile surface structure on the inner side of the base body that is different from an otherwise smooth integral skin surface. 
     The textile can be flexible, in particular elastic, in order to be able to adapt to the outer contour of a tool core and thus to the sometimes complex inner contour of the cavity. The textile is preferably tear-resistant in order to provide sufficient additional stability of the base body. 
     The foam material, at least in some regions, cannot penetrate the textile, such that no foam material forms the inner surface of the cavity. A textile inner surface is thus formed. 
     In the method for producing a molded part, in particular a prosthesis cosmetic, from a foam material with a cavity formed in the molded part for receiving a further component, for example a prosthesis component, in which method a tool core is introduced into a mold cavity of a molding tool and the mold cavity is filled with the foam material, provision is made that the tool core is at least partially covered on its outer side with a textile before the mold cavity is filled with the foam material. The textile can be placed on the tool core. It is likewise possible for the textile to be wrapped around the tool core. The tool core can be completely covered with the textile on its circumference. There is also the possibility of arranging several textiles on the tool core, for example also arranging several layers of a textile or of different textiles on top of one another in order to connect them to the foam material during foaming and to integrate them into the base body. If the tool core protrudes into the mold cavity, the tip protruding into the mold cavity can also be completely covered by the textile. If the tool core protrudes right through the mold cavity, the respective end faces of the tool core are advantageously not covered, and only the lateral surface of the tool core is covered. The textile can also be pulled onto the tool core if it has been manufactured from a tube in a previous work step or has been produced to form a tubular molded body. 
     A textile tube can be pulled onto the tool core, onto which textile tube the outer shape of the base body is then foamed. After the mold cavity has been filled with foam, the molded body is removed from the mold and the tool core is removed to form the hollow body. The outer contour of the molded body is then generated using at least one cutting method, in particular grinding. 
     The integral production of the cavity with the textile reinforcement facilitates the production of the base body and the further processing to the final product, or to an intermediate product which is then further processed. The work safety when processing the base body is improved. The durability of the products produced by the foaming is increased, and the usage behavior or operating behavior of the molded bodies is also improved. The foam material can be designed to be stable under pressure, and a certain flexibility and elasticity can also be provided by the foam material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An exemplary embodiment of the invention is explained in more detail below with reference to the accompanying figures, in which: 
         FIG.  1    shows a schematic flow chart of the production method; 
         FIG.  2    shows a sewn textile tube and a tool core; and 
         FIG.  3    shows a partial view of a produced prosthesis cosmetic with a textile reinforcement. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    shows a schematic flow chart for the production of a molded part  30 , in particular a prosthesis cosmetic. First, a tool core  10  is manufactured or made available, which tool core  10  is designed to receive a further component, for example a prosthesis component. The outer contour of the tool core  10  can correspond substantially to the outer contour of the component to be received, in particular the prosthesis cosmetic, optionally with additions or deductions and also with formations and projections for securing to the component or the prosthesis cosmetic. A textile  20  is applied to the outer side of the tool core  10 . The textile  20  in the exemplary embodiment shown is tubular and designed to be closed at the upper end. It is possible to insert the tool core  10  into the textile  20  through the lower insertion opening. The textile  20  can be formed in one piece, for example knitted or woven, or alternatively it can be made from a flat blank which is sewn or glued accordingly. It is likewise possible to obtain the desired covering from a tubular base body by closing an opening. The textile  20  surrounds the tool core  10  on the outer circumference and at the upper end; the lower end can be left free. 
     After the tool core  10  has been inserted into the textile  20  or after the tool core  10  has been enveloped with the textile  20  in another way, for example by wrapping, the tool core  10  is inserted into a molding tool  60  that has a mold cavity  65 . One end of the tool core  10  with the textile  20  forms a closure with a wall of the molding tool  60 ; alternatively, one end of the tool core  10  protrudes from the molding tool  60 . Alternatively, it is possible that the tool core  10  also extends right through the molding tool  60 . 
     The mold cavity  65  of the molding tool  60  is then filled with a foam material  40 , such that a base body  30  is formed from a foam material  40 , with a corresponding cavity in its interior after the base body  30  has been removed from the molding tool  60  and the tool core  10  has been removed. The outer contour of the base body  30  corresponds to the inner contour of the molding tool  40  and can be cylindrical, for example. Alternative outer contours are likewise possible, for example conical or roughly approximating to an outer contour of the desired insert shape. The molded body can be used, for example, as a prosthesis cosmetic and can cover a lower leg component of a prosthetic fitting of a lower extremity. A contour of the base body  30 , designed approximating to an outer contour of a lower leg, then facilitates the individualization and adaptation to the respective user. 
     After the removal of the base body  30  and of the tool core  10 , the outer contour of the base body  30  is machined, which can be seen in the illustration on the right in  FIG.  1   . The base body  30  is given the desired contour on the outer side  32  by suitable machining methods, for example by grinding or another cutting method. For this purpose, the foam material  40  is either fastened to a carrier or held by a person. Within the foam material  40 , which can also have a certain elasticity, a cavity  50  has been created by the removal of the tool core  10 , such that an inner side  31  with an inner surface is present within the base body  30 . After the tool core  10  has been removed, the textile  20  is still arranged on the inner side  31  and is permanently connected to the base body  30  and thus to the foam material by the foaming. The textile  20  is foamed into the base body  30  and increases the stability, in particular when the foam material  40  is removed with a corresponding tool, for example with a grinding wheel or a milling head, until very close to the cavity  50 . The textile  20  can be designed to be flexible, in particular elastic. The process control during foaming can be chosen in such a way that the foam material  40  does not penetrate through the textile  20 , or at least in some regions does not penetrate through the textile  20 . This ensures that the inner side  31  of the base body  30  and thus the cavity  50  are covered with the textile  20 , at least in those regions where the foam material  40  has not penetrated the textile  20 . Even if the foam material  40  penetrates the textile  20 , the textile  20  increases the stability within the base body  30  and reduces the tendency of the foam material  40  to tear at low material thicknesses and thereby render the molded body or the prosthesis cosmetic unusable. 
     An exemplary embodiment of a tool core  10  and of a textile  20  is shown in  FIG.  2   . In its left-hand region, the tool core  10  has a thickening with an outer contour which corresponds to a lower part of a prosthetic knee joint. Damper devices, actuators, control devices and the like can be arranged on this lower part. The tool core  10  only reproduces the outer contour of the prosthesis component together with a lower-leg tube connected thereto. The tool core  10  can be made of a plastic or a metal. 
     The textile  20  that is to be pulled over the tool core  10  is shown below the tool core  10 . The textile  20  is produced from a basic blank which is folded along an axis of symmetry and sewn along an outer edge, which is arranged at the top in the exemplary embodiment shown, to form a tubular cover. The textile  20  of  FIG.  2    is designed to be open at both ends, and the right-hand end is first pulled over the left-hand end of the tool core  10  until it envelops the outer side of the tool core  10  except for the end faces. The textile  20  is advantageously designed to be flexible, such that it lies tightly against the tool core  10  when inserted into the molding tool  60 . 
       FIG.  3    shows a detailed view of a finished prosthesis cosmetic  100 . The outer contour of the prosthesis cosmetic  100  is designed to approximate to the contour of a calf or of a lower leg. The foam material is ground on the outer side  32 , and the inner side  31  is lined with the textile  20 , such that the cavity  50  is completely provided with a textile  20  on the inner side  31 . The initially closed base body has been opened in the region of the calf, opposite the shinbone, i.e. on the rear side, such that the prosthesis cosmetic  100  can be bent open along the separating edge or cutting line and laid around the prosthesis component, which is not shown.