Textiles: ironing or smoothing – Smoothing implements – Stretchers
Patent
1994-01-14
1996-02-06
Willse, David H.
Textiles: ironing or smoothing
Smoothing implements
Stretchers
381024, 3810291, 623 2, 623901, D05B 9110, D05C 104, A61F 224
Patent
active
054887895
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a process for covering an annular support of a heart valve prosthesis with a textile covering, and to an apparatus for carrying out the process.
The known prostheses used in cardiac surgery contain a crown-shaped annular element of plastic, but generally of metal or of both materials. They consist in general of long, often wire-like elements which are predominantly not very elastic and are often joined by soldering or welding. This results in poor adaptability, especially since the joints then become brittle, but in some cases also relatively poor tolerance, not least because the textile covering generally applied to the annular element then requires several seams in order to hold securely on the wire skeleton of the annular element. This results in strength problems and also can make manufacture more difficult. Typical heart valve prostheses of this type are described in U.S. Pat. No. 3,570,014 or U.S. Pat. No. 3,755,823.
SUMMARY OF THE INVENTION
It is the object of the invention to design a heart valve prosthesis of the type described above in such a way that the adaptability and tolerance are improved, strength problems being avoided. This is achieved according to the invention by covering an annular support of a heart valve prosthesis with a textile covering that is elastic at least in one direction. The textile covering is pushed into the annular support and, at its two projecting axial ends, the textile covering is turned over the outer surface of the annular support. The two axial ends of the textile covering then are joined to one another by a seam, which extends around the annular support.
By means of the process according to the invention, the textile covering is mounted on the annular element with a minimum of seams. Thus, on the one hand, the tolerance improves since a plurality of thick seams is avoided but the strength is also improved as a result, since seams always entail a mechanical risk. It would of course also be possible to apply the process according to the invention to conventional annular elements, but it is precisely in combination with a particular, preferred support, disclosed herein, which provides results optimum results.
Although the process according to the invention could also be realised without an apparatus of a particular type, the apparatus according to the invention not only considerably helps and facilitates the implementation of the process and the production of a prosthesis according to the invention but also guarantees uniform quality through the clamping apparatus provided according to the invention. The preferred apparatus for performing this process includes two coaxial rings, which hold the annular support together with the textile covering during assembly. One of the rings includes a fastener for one end of the textile covering. The other ring includes a clamping apparatus for the other end of the textile covering.
BRIEF DESCRIPTION OF THE DRAWINGS
Further details of the invention are evident from the following description of embodiments shown schematically in the drawing.
FIG. 1 shows a heart valve prosthesis according to the invention before attachment of the biological heart valve material;
FIGS. 2 to 6 show the successive steps in carrying out the process according to the invention, starting from a rectangular piece of material according to FIG. 2; and
FIG. 7 shows an apparatus according to the invention for carrying out this process.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows an oblique view of a heart valve prosthesis 1 according to the invention with partly removed textile covering 3, which covers an annular support 1a together with a collar 2 attached thereto. As can be seen, the annular element 1a consists of flat material, in particular of a thermoplastic, so that it can be produced easily and economically, for example by injection moulding.
The support 1a possesses, in a manner known per se, three axially projecting support arms 4, the free ends of which are rounded. P
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Cichon Romuald
Kryzskow Marek
Religa Zbigniew
Stolarzewicz Bogdan
Stozek Jolanta
Nika Health Products Limited
Willse David H.
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