Seal arrangement for residual limb prosthetic socket
View Patent ↗A prosthetic socket seal includes at least one radially projecting sealing lip which jointly with a base subtends an annular gap. This annular gap is vented on a proximal side by the external atmosphere, resulting in creation of a pressure gradient at the sealing lip that produces stronger compression of the sealing lip against the prosthetic socket with increasing partial vacuum on a distal side of the sealing lip.
1. A seal for sealing a distal portion of a residual limb within a cup-shaped air tight prosthetic socket comprising:
a base having proximal and distal ends adapted to be pulled onto a residual limb and to enclose at least a portion of a residual limb peripherally;
at least one sealing lip having a root and a flexibly compliant sealing edge that is spaced from the root and is arranged so as to hermetically rest against an inner wall area of a prosthetic socket and which is affixed by its root to the base;
said sealing lip open to ambient air between its connection with the base and its sealing edge;
said lip extending along a longitudinal direction of the base from the distal end towards the proximal end thereof and diagonally diverging therefrom at least in part in a direction towards the proximal end of the base;
wherein the base and sealing lip are annular.
2. The seal as claimed in claim 1 , wherein the base comprises at least a second sealing lip which comprises a second sealing edge that is spaced from the root and is configured to hermetically rest against a residual limb, and wherein the second lip extends peripherally and continuously to enable the second sealing lip to enclose a residual limb, and further wherein the second sealing lip is affixed by its root to said base.
3. The seal as claimed in claim 1 , wherein said sealing lip is elastically stretchable at least in a direction parallel to the sealing edge.
4. The seal as claimed in claim 3 , wherein when the seal is in an operational position on a residual limb, the sealing edge of the sealing lip extends toward a proximal end of a residual limb.
5. The seal as claimed in claim 1 , wherein the sealing lip is made of a material that may elastically closely conform to a contour.
6. The seal as claimed in claim 1 , wherein sealing lip contains magnetized ferromagnetic particles.
7. The seal as claimed in claim 1 , wherein the base comprises a prosthetic suction liner which is air tight at least in the vicinity of the root of the sealing lip.
8. The seal as claimed in claim 1 , wherein the base comprises a cuff which is adapted to engage a residual limb in an air tight manner at least in the region of the root.
9. The seal as claimed in claim 1 , including a venting device comprising a spacer located between the base and the sealing lip, said spacing maintaining the area between the base and the sealing lip open to ambient air.
10. The seal as claimed in claim 9 , wherein the spacer is resiliently compressible.
11. The seal as claimed in claim 9 , wherein the spacer is made of open-cell foam.
12. The seal as claimed in claim 9 , wherein the spacer runs peripherally along the sealing lip at least over nearly a full length of the seal.
13. The seal as claimed in claim 1 , wherein the sealing lip is configured in a manner to form a bend pointing away from the residual limb whereby, in its operational position, the sealing edge of the sealing lip subtends a cross-sectional surface which is larger than that subtended by the root of the sealing lip.
14. The seal as claimed in claim 1 , wherein the sealing lip has a length measured between the root and the sealing edge such that said lip may be outwardly folded over itself.
15. A prosthetic socket using a seal as defined in claim 1 .
16. The prosthetic socket as claimed in claim 15 , wherein the seal contains magnetized or unmagnetized ferromagnetic particles in its socket wall at least in the region which is opposite the sealing lip of the seal.