Abstract:
A fitting including an electrode assembly mounted and sealed therein. The fitting configured to be positioned within an aperture in a wall of a socket of a prosthetic apparatus. The prosthetic apparatus may include an external socket that receives and is attached to the socket as an internal socket. The electrode assembly has one or more skin contacts for conduction of myoelectrical signals to a prosthetic system. The fitting includes a groove and a retention rim to secure and seal the fitting within the aperture in the socket wall, in order to prevent the passage of air and moisture from the interior of the socket when a stump of a limb is received therein. A unidirectional valve provides for the release of air from the interior of the socket.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This patent application claims priority from German Patent Application No. 20 2006 007 460.0, filed on May 9, 2006 and entitled “PROTHESENINNINSCHAFTSYSTEM”, the entire contents of which are hereby expressly incorporated by reference. 
   TECHNICAL FIELD 
   This invention relates to the field of artificial prostheses for human limbs. More particularly, the present invention relates to the field of prostheses having an internal socket received and secured within an external socket. 
   BACKGROUND 
   Prosthetic elements, such as prosthetic knee joints, artificial lower legs or artificial hands are attached to prosthesis sockets, which are situated on the relevant stump of the prosthetic user. According to the desired scope or function, there is a differentiation between purely cosmetic prostheses, mechanically activated prostheses and bioelectrically controlled prostheses. The relevant extremity to be replaced, or functional element to be provided, is typically located on the exterior socket, which is attached directly to the internal socket carried on the stump. 
   In myoelectrically powered prostheses, the conduction of an electrical action potential from the stump musculature is necessary. These potentials are emitted by the contraction of a muscle and are measurable on the skin surface of the prosthetic wearer. The potentials collected by an electrode are amplified and sent to the control unit, which activates or deactivates the actuators. The state of the art is to equip the internal socket with a recess or aperture in which the electrode can be inserted. Between the electrode and the recess in the internal socket there is a particular gap which can lead to a relative movement between the electrode and the internal socket. Through the gap between the internal socket and the electrode, perspiration can enter the space between the internal socket and the external socket, which can affect the electrical and electronic components. This can also make cleaning the internal socket difficult. 
   SUMMARY OF THE INVENTION 
   The present invention provides an improved internal socket fitting and system in which these disadvantages do not arise. The present invention includes an internal socket which is capable of being assembled within a prosthetic external socket with accommodation features for additional prosthetic components (not shown). The internal socket has at least one recess provided for the communication of myoelectrical signals to an electrode assembly located on the internal socket. The electrode assembly is attached to and retained by a fitting received in and providing a moisture seal for the recess. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a bottom plan view of an electrode assembly and fitting useful in the practice of the present invention. 
       FIG. 2  shows a side elevation view of the electrode assembly and fitting of  FIG. 1 . 
       FIG. 3  shows a first perspective view from the top of the electrode assembly and fitting of  FIG. 1 . 
       FIG. 4  shows a second perspective view from the bottom of the electrode assembly and fitting of  FIG. 3 . 
       FIG. 5  shows a perspective view from the top of the fitting without the electrode assembly. 
       FIG. 6  shows a perspective view from the bottom of the fitting of  FIG. 5  without the electrode assembly. 
       FIG. 7  shows a perspective view of an internal socket from a proximal end of the socket with the electrode assembly and fitting installed therein. 
       FIG. 8  shows a side view of an assembly of an external socket and internal socket with portions of each cut away to illustrate certain aspects of the present invention. 
   

   DETAILED DESCRIPTION 
   Referring to the Figures, the present invention includes a fitting  1  carrying an electrode assembly  2 , wherein the fitting is received in an internal socket  30  which is capable of being assembled within a prosthetic external socket  40  with accommodation features for additional prosthetic components (not shown). 
   The internal socket  30  has at least one recess or aperture  8  provided for the communication of myoelectrical signals through the electrode assembly  2  located on the internal socket  30 . The electrode assembly  2  is attached to and retained by the fitting  1  received in and providing a moisture seal for the aperture  8 . In one embodiment, it has been found desirable to construct the internal socket  30  as a suction socket, so that there is no gap between any of the internal socket  30 , the electrode assembly  2  and the fitting  1 . Air or perspiration is prevented from entering or exiting the intersocket space  9  between an external socket  40  and the internal socket  30 . Therefore any prosthesis components in the intersocket space are protected from perspiration entering from the interior of the internal socket  30 . During cleaning or when using a skin cream on the limb, material is prevented from entering the intersocket space  9  from the interior of the internal socket  30 . Through airtight assembly of the fitting with the electrode assembly  2  onto the internal socket  30 , at least a partial vacuum may be created, to improve contact between the stump and the electrode assembly  2  to improve the reliability of contact and therefore consistent sensing of myoelectrical signals by the electrode assembly  2 . 
   Creation and maintenance of at least partial vacuum in the interior of the internal socket  30  also aids in (removably) securing the internal socket  30  to the stump. 
   Manufacture of the internal socket  30  is made easier, because it can be formed as a laminated or deep drawn structure, into which the aperture  8  may be formed or cut in accordance with the stump model in the course of manufacture. 
   The fitting  1  is preferably formed of an elastic or resilient material, which may be a polymer such as a silicone or other skin friendly or cutaneous tolerant material. A support structure (such as that shown as a T-shaped element  20  in  FIGS. 4 and 5 ) for the electrode assembly  2  can be provided, as by inserting or injecting material into the fitting, for example within the framework of a two component injection method, or a support structure may be adhered, pressed or form-fit to the fitting  1 , or formed integrally therewith, to result in a sealed arrangement between the fitting  1  and the electrode assembly  2 . A groove  10  is preferably formed circumferentially around the fitting  1  and congruent to the aperture  8 , so that the fitting  1  completely covers the internal and external edges of the aperture  8  in the internal socket  30 . In this way, the aperture  8  in internal socket  30  is enclosed within two seal lips  18  and  19  which abut surfaces of the internal socket  30  when the fitting  1  is installed. 
   A further aspect of the present invention provides that the internal socket  30  is attached to the external socket  40  with a tube or passageway  50  onto which additional prosthesis parts may be attached. Such a passageway is preferred for insertion of the stump into the internal socket  30 . A unidirectional valve  17  may be attached to the passageway  50  fluidly connected with the internal socket  30  to permit expulsion of air out of the volume between the stump and the internal socket  30  upon movement of the stump into or within the internal socket  30 . The valve  17  can be located within the connection tube  50  between the internal and external sockets  30  and  40  and is operable to close the fluid passageway  50  from the internal socket  30  to the external ambient atmosphere. The design and adjustment of the valve  17  and the arrangement of the attachment tube  50  with respect to the internal socket  30  may be chosen to restrict or prevent the entrance of soft tissue into the tube  50 . 
   It is preferred that the fitting  1  be resilient or pliable, in order to be conformable to irregularities in the stump, so that good electrical contact is provided and maintained between the electrode assembly  2  and the skin. 
   The top side of the fitting  1  is to be understood as the side facing toward the stump. The top side is preferably convex, and may be characterized as a flattened spherical cap. It has been found desirable that the shape of the fitting  1  with the electrode assembly  2  installed has no, or only slight, pressure points on the stump, achieved by having a low profile, i.e., only a slight projection away from the interior surface of the internal socket  30 . 
   Fitting  1  may be inserted into the aperture  8  of the internal socket  30  by pressing or snapping into place. A curable sealant such as a curable polymer, possibly formed of silicone, may be used in the groove  10  or in the contact area between the internal socket  30  and the fitting  1  to provide a better seal. 
   In  FIG. 1 , fitting  1  is shown with electrode assembly  2  inserted. An electrical connector  3  has skin contacts  4 ,  5 , and  6  for conduction of the action potentials of the abutting muscle groups. In the side view of  FIG. 2 , one form of convex construction of the top (or stump side surface)  13  of the fitting  1 , along with the groove  10  and the retention rim  11  may be seen. The edge of the aperture  8  of the internal socket  30  is received in the groove  10 . In one embodiment, the electrode assembly  2  may be inserted into a recess or opening  12  in the fitting  1  from the bottom side of the fitting  1  (i.e., the side of the fitting intended to face the intersocket space  9 ). The dimensions of the electrode assembly  2  may be greater than the corresponding dimensions of the opening  12  such that the fitting  1  is caused to extend outward, conforming the periphery of the groove  10  to the shape of the aperture  8  in the internal socket  30 . Consequently, the internal and external edges of aperture  8  are urged into intimate and continuous contact within the groove  10 . As a result, the region adjacent the aperture  8  in the internal socket  30  is covered by the internal side of the fitting  1 , which may be configured as a flange or other structure, and the retention rim  11 , and an air and watertight seal is created between the fitting  1  and the internal socket  30 . 
   A rotary switch  7  on the back (or bottom) side of the electrode assembly  2  enables adjustment of the electrode assembly  2 . 
   The electrode assembly  2  can be injected, adhered, pressed or form-fit into the fitting  1 . In the perspective views of  FIGS. 3 &amp; 4 , one can see the finished mounted electrode assembly  2  in fitting  1 . 
   With a design having the electrode assembly  2  initially separate from the fitting  1 , the fitting  1 , as shown in  FIGS. 5 and 6  in various views, may be made as a molded part or injection molded part of a skin tolerable material, such as a polymer, for example, silicone. The fitting  1  may be equipped with opening  12  for the insertion of the electrode assembly  2 . 
   In  FIG. 7 , the internal socket  30  is represented diagonally from the back or proximal end, i.e., from the insertion direction of the stump, an arm stump for example. The internal socket  30  may be constructed as a suction socket. In this view, the electrode assembly  2  may be seen inside the internal socket  30 . The contour of the fitting  1  on the internal side of socket  30  is preferably only slightly convex, in order to provide the most comfortable feeling for the wearer without pressure points. This also provides a secure connection between the skin contacts  4 ,  5 ,  6  and the stump, so that there is a reliable electro-myographic signal path established and maintained. As described above, the fitting  1  is equipped with groove  10 , which is sealed to the internal socket  30 , to prevent entry of air or moisture from the internal side of socket  30  into the intersocket space  9 . 
   In  FIG. 8 , a prosthesis apparatus may be seen with an internal socket  30 , and an external socket  40 , with each of the internal and external sockets  30 ,  40  shown in a partially cutaway representation. The internal socket  30  may be secured via screws  34  to the exterior socket  40 . In addition, an access hole  32  may be provided in the external socket  40 , through which the electrode assembly  2  (attached to internal socket  30 ), can be adjusted by manipulation of rotational switch  7 . The periphery of access hole  32  may be sealed against the entry of moisture and other contaminants from the external ambient environment, if desired. 
   In the partial cutaway representation of  FIG. 8 , the internal socket  30  is attached to the external socket  40  or exterior of the external socket  40  via a connection tube or passageway  50 . The connection tube  50  enables escape of the air in the internal socket  30  to an appropriate location in the external socket  40  or to the external ambient environment. In order to prevent back flow of air, a unidirectional valve  17  is located in the connection tube  50 . Through use of a lever  15 , an O-ring  16  is activated within the connection tube  50  and thereby seals off the internal socket  30 . Air can then only escape through he unidirectional valve  17 . 
   The invention is not to be taken as limited to all of the details thereof as modifications and variations thereof may be made without departing from the spirit or scope of the invention.