Valve system for prosthetics
View Patent ↗A valve system regulates the air pressure in the space(s) between a residual limb, or liner-covered limb, and a hard socket of an external prosthesis, and may include a manually-controlled air outlet and inlet valve on a distal region of a hard socket, and/or an automatic one-way outlet valve. The manually-controlled valve is opened and closed by partial rotation/twisting of a handle portion, which creates slight separation of the handle and base portions through which may pass air. The handle and base are prevented from becoming entirely separated during normal use by a snap-fit of the base onto the handle that retains the ability of the handle and base to rotate relative to each other by means of a ramp system, and a stop(s) that limit(s) the amount of relative rotation of the handle and base portions of the valve.
1. A pressure-control system for a prosthetic hard socket, the pressure-control system comprising:
a prosthetic socket comprising a wall having an outer surface and an interior surface defining a well for receiving a residual limb, and said wall having a hole extending from said outer surface to said interior surface; and
a valve system comprising:
a base connected to said outer surface and having a base bore positioned over said hole in the wall;
a handle connected to said base by a rear portion of the handle snapping into the base and having a handle bore generally coaxially aligned with said base bore and in fluid communication with said hole in the socket wall;
a valve casing connected to said handle and having a casing bore generally coaxial, and in fluid communication, with said handle bore and said base bore;
a valve stem slidably received in said casing bore and slidable into a first, sealed position wherein a portion of said valve stem seals against a sealing surface of the valve casing and into a second, unsealed position away from the valve casing sealing surface; and
a spring biasing the valve stem into the first, sealed position until said air pressure inside the prosthetic socket well is at a differential pressure in the range of 1-3 psi greater than ambient pressure outside the socket, at which time the valve stem is pushed by said differential pressure into said second, unsealed position so that air leaves the socket well by flowing through the hole, the base bore, the handle bore, and the casing bore;
wherein the handle is rotatable in a first direction a portion of a full rotation in the range of only 30-90 degrees relative to the base to an open position forming a radial gap between said base and said handle, so that air from the socket well passes axially through the hole and the base bore, and radially through said radial gap, wherein rotation of said handle 30-90 degress relative to the base forms said radial gap by means of two handle ramps provided on an outer surface of the rear portion of the handle sliding relative to two cooperating base ramps provided on an inner surface of the base, said two handle ramps being spaced 180 degrees apart on said outer surface of the rear portion of the handle, and said two handle ramps and said two base ramps being slanted so that the handle rotating said 30-90 degree portion of a full rotation moves the handle axially out from the base to form said radial gap; and
wherein said valve system comprises a limit mechanism at each end of each of said two handle ramps and a tab at an end of each of said two base ramps, wherein the limit mechanism and the tabs prevent said handle from rotating in said first direction more than said 30-90 degree portion of a full rotation.
2. A pressure-control system as in claim 1 , wherein said valve stem is non-cylindrical.
3. A pressure-control system as in claim 1 , wherein said valve stem is non-circular in radial cross-section.
4. A pressure-control system as in claim 2 , wherein said valve stem is polygonal.
5. A pressure-control system as in claim 1 , wherein said base is adhesively attached to the socket and no part of the valve system extends through the socket into the well of the socket.
6. A pressure-control system as in claim 1 , wherein said handle has a polygonal exterior surface.
7. A pressure-control system as in claim 1 , wherein said portion of a full rotation is in the range of 30-90 degrees.
8. A pressure-control system as in claim 1 , wherein: said valve stem has a valve stem circumference and said valve casing has a casing bore circumference, and wherein said valve stem circumference is not the same shape as the casing bore circumference, and one of said casing bore circumference or said valve stem circumference is non-circular, so that, when the valve stem is in the second, unsealed position, air flows around the valve stem through axial gaps between the valve stem and the valve casing.
9. A pressure-control system as in claim 8 , wherein said valve stem is polygonal and the casing bore is cylindrical.
10. A pressure-control system as in claim 8 , wherein no part of the valve system extends through said socket wall into the socket well.
11. A pressure-control system as in claim 8 , wherein said base is adhesively attached to the socket and no part of the valve system extends through the socket into the well of the socket.
12. A pressure-control system as in claim 8 , wherein said casing housing has a polygonal exterior surface.
13. A pressure-control system as in claim 8 , wherein said valve stem has a hollow end that receives a portion of said spring.