Electrolysis: processes – compositions used therein – and methods – Electrolytic erosion of a workpiece for shape or surface... – With programmed – cyclic – or time responsive control
Reexamination Certificate
1998-07-02
2001-10-09
Valentine, Donald R. (Department: 1741)
Electrolysis: processes, compositions used therein, and methods
Electrolytic erosion of a workpiece for shape or surface...
With programmed, cyclic, or time responsive control
C205S686000
Reexamination Certificate
active
06299755
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to methods of fabricating stents.
BACKGROUND OF THE INVENTION
Stents are known in the art. They are typically formed of a cylindrical metal mesh which can expand when pressure is internally applied. Alternatively, they can be formed of wire wrapped into a cylindrical shape.
As described in U.S. Pat. No. 4,776,337 to Palmaz, the cylindrical metal mesh shape is produced by laser cutting a thin walled metal tube. The laser cuts away all but the lines and curves of the mesh.
The method of U.S. '337 is applicable for relatively large mesh shapes and for meshes whose lines are relatively wide. However, for more delicate and/or intricate shapes, the spot size of the laser is too large.
SUMMARY OF THE PRESENT INVENTION
It is, therefore, an object of the present invention to provide a stent fabrication method which can produce stents with relatively intricate and/or delicate designs.
The method involves first creating a flat version of the desired stent pattern from a piece of thin sheet metal. The flat pattern can be produced through any suitable technique, such as etching the design into the sheet metal, or by cutting with a very fine laser, should one become commercially available or by any other technique.
Once the sheet metal has been cut, it is deformed so as to cause its edges to meet. To create a cylindrical stent from a flat, roughly rectangular metal pattern, the flat metal is rolled until the edges meet. The locations where edges meet are joined together, such as by spot welding. Afterwards, the stent is polished, either mechanically or electrochemically.
It is an object of this invention to provide an apparatus for fabricating a stent, comprising:
a) a platform adapted to receive a flat sheet of metal to be formed into the stent, the flat sheet of metal having a longitudinal axis, a first major surface, a second major surface, a first long side, and a second long side, the first and the second long sides substantially parallel to the longitudinal axis of the sheet;
b) a mandrel having a substantially cylindrical external surface and having a first end and a second end defining a longitudinal axis, the mandrel sized to have a cross-sectional diameter substantially equal to or less than the internal diameter of the stent to be fabricated;
c) means for securing the mandrel against a major surface of the flat sheet of metal; and
d) means for deforming the flat sheet of metal against the external surface of the mandrel so that the flat sheet of metal is deformed into a substantially tubular shape, the means for deforming adapted so that the first long side and the second long side remain substantially parallel to each other when the flat sheet of metal is deformed into the tubular shape.
It is another object of this invention to provide and apparatus for fabricating a stent, comprising:
a) a base having a platform adapted to receive a flat sheet of metal to be formed into the stent, the flat sheet of metal having a longitudinal axis, a first major surface, a second major surface, a first long side, and a second long side, the first and the second long sides substantially parallel to the longitudinal axis of the stent;
b) a mandrel having a substantially cylindrical external surface and having a first end and a second end defining a longitudinal axis, the mandrel sized to have a cross-sectional diameter substantially equal to or less than the internal diameter of the stent to be fabricated;
c) means for securing the mandrel against a major surface of the flat sheet of metal;
d) a plurality of deforming blades disposed around the periphery of the mandrel for deforming the flat sheet of metal against the external surface of the mandrel so that the flat sheet of metal is deformed into a substantially tubular shape, the blades disposed between the first end and the second end of the mandrel, each of the deforming blades adapted for independent and selective movement in a first direction toward the mandrel and a second direction away from the mandrel so as to selectively impinge upon the mandrel or upon a portion of the sheet disposed between the mandrel and each of the deforming blades, each of the deforming blades further adapted so that the first long side and the second long side of the sheet remain substantially parallel to each other when the stent is deformed into the tubular shape;
e) means for selectively moving each of the deforming blades in a first direction toward the mandrel and in a second direction away from the mandrel; and
f) means for securing the first long side of the sheet to the second long side of the sheet.
It is yet another object of this invention to provide an apparatus for fabricating a stent, comprising:
means for securing the first long side of the sheet to the second long side of the sheet.
It is still another object of this invention to provide an apparatus for fabricating a stent, comprising:
a) a base;
b) a sheet receiving area disposed on the base, the area adapted to receive a flat sheet of metal to be formed into the stent, the flat sheet of metal having a longitudinal axis, a first major surface, a second major surface, a first long side, and a second long side, the first and the second long sides substantially parallel to the longitudinal axis;
c) an arm having a first end and a second end, the first end of the arm adapted to selectively retain a mandrel having a substantially cylindrical external surface, the second end of the arm hingedly connected to the base and adapted for movement in a first direction toward the base and in a second direction away rom the base and further adapted to secure the mandrel against a major surface of the flat sheet of metal disposed on the stent receiving area disposed on the base, the mandrel sized to have a cross-sectional diameter substantially equal to or less than the internal cross-sectional diameter of the stent to be fabricated;
d) means for deforming the flat piece of metal against the external surface of the mandrel so that the flat sheet of metal is deformed into a substantially tubular shape substantially conforming to the external surface of the mandrel with the first long side and the second long side substantially parallel to each other.
It is yet another object of this invention to provide a stent aligning and welding jig comprising:
a) a base having a first end and a second end, a first wall having a first end and a second end and a first major surface and a second major surface; a second wall having a first end and a second end and a first major surface and a second major surface, the second major surface of the first wall and the first major surface of the second wall defining a longitudinal U-shaped channel having a longitudinal axis in the base, the first wall provided with a plurality of slots defining a plurality of first clamping portions having a top end and a bottom end and a first major surface and a second major surface, each of the first clamping portions provided with a first concave channel disposed at the top end of the second major surface of the first clamping portion and a second concave channel disposed at the bottom end of the second major surface of the first clamping portion, the first and the second concave channels substantially parallel to the longitudinal axis of the U-shaped channel; the first wall of each of the plurality of first clamping portions provided with a compensation slit disposed between the first concave channel and the second concave channel, the compensation slit substantially parallel to the longitudinal axis of the U-shaped channel;
b) a plurality of second clamping portions disposed in the U-shaped channel between the second major surface of the first wall and the first major surface of the second wall, each of the second clamping portions disposed in registry with one of the first clamping portions, each of the second clamping portions having a top end, a bottom end, a first major surface, a second major surface, a first minor surface disposed at the top end, a second minor surface
Kenyon & Kenyon
Medinol Ltd.
Valentine Donald R.
LandOfFree
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