Hollow conductive medical tubing
AssigneeBerkley, Inc.
InventorsRobert L. McMickle, James T. Rumbaugh, Robert L. Netsch
Life of this patent
Estimating the term…
Abstract
A body implantable intravascular lead with a first layer of plastic defining a tube having a precision lumen therein and at least one electrical conductor wrapped helically along the length of one or more plastic layers. The conductors are substantially parallel along the axis at each end for ease of connection to electrodes and the helical wrap of the conductors may vary throughout the length to form a first length having a first flexibility and a second length having a greater flexibility incapable of sustaining the same axial mechanical loading. The conductive wires are overlaid with one or more layers of plastic separately insulating the wires from each other.
Claims8
A continuous process of forming a plurality of conductive body implantable leads each having a lumen of tight inside dimensional tolerances, comprising the steps of:
- providing a continuous core material;
- extruding a first layer of body-compatible non-conductive plastic material onto the core;
- winding a plurality of electrical conductors on the coated core such that each conductor forms a helix physically separated from each other conductor, the positioning and orientation of the conductors prior to being wound onto the coated core being evenly distributed about the circumference of the wire thereby to balance the tension forces applied to the structure as the conductors are wound;
- extruding a coating over the electrical conductors and said coating with a second coating of body-compatible non-conductive plastic material, said second coating being compatible with said first coating and electrically insulating the individual conductors of such helix from each other;
- cutting the coated and conductive core material into lengths;
- and
- removing the core material from the first layer of plastic material.
The process of forming conductive body implantable leads with a lumen of tight inside dimensional tolerances comprising the steps of:
- extruding a continuous core wire of predetermined cross-sectional shape with a body-compatible non-conductive plastic material by means of a crosshead extruder;
- quenching or curing the plastic as required;
- winding a plurality of electrical conductors on the coated core wire such that each conductor forms a helix about the coated core wire physically separated from each other and extending along the length thereof;
- varying the pitch of the helices formed by the electrical conductors at predetermined locations along the length of the coated core wire such that the conductors are substantially parallel at the ends of each length so as to be at a maximum physical separation from each other, and winding the conductors relatively tighter at one end of the length than the other end forming a length with greater flexibility at the tight end than the other end;
- extruding an additional layer of a body-compatible non-conductive plastic material onto the conductive coated core wire by means of a crosshead extruder and curing or quenching as required;
- cutting said coated core wire into discrete lengths;
- and
- removing said core wire from said plastic coating to provide hollow body implantable leads.
A method for manufacturing lengths of tubing having multifilar longitudinally extending helices surrounding a dimensionally controlled inner lumen therein, the method comprising the steps of:
- supplying a continuous strand of base wire from a wire dispenser;
- extruding a first layer of a plastic material over the base wire to form a coated tube;
- supplying a plurality of continuous filaments from a plurality of filament dispensers positioned at equally spaced intervals around a rotor table;
- connecting each of the filaments to the coated tube;
- transporting the coated tube at a first rate along a transport path through the center of rotation of the rotor table while rotating the rotor table about the transport path at a first rate to wrap the plurality of filaments into a plurality of helices, each of which is in spaced relation to the adjacent helices;
- extruding a second layer of a plastic material over the first layer and the filaments;
- cutting the material into lengths of tubing;
- and
- removing the base wire from each of the lengths of tubing to form the inner lumen.
Dependencies are inferred from the claim text.