Patent Application
20220023644
An implantable medical lead typically includes a tubular-shaped main lead having one or more conductors or coils to sense or provide stimulative biologic, electrical signals, and a lead connector coupled to one end of the main lead. In one embodiment, the lead connector is, in-turn, configured to electrically and mechanically plug into and couple to a header or connector bore of a pacemaker, implantable cardioverter defibrillator (“ICD”), or other type of pulse generator.
One type of implantable medical lead includes an IS4/DF4 lead connector, which is a standardized lead connector having an injection molded, reaction injection molded (RIM) or potted, cylindrical body (typically of a thermoplastic, or thermoset material). The connector body has a proximal end configured to connect into a header of an active implantable device of some type, and a distal end configured to connect to the conductors/coils within the main lead. Such lead connectors have multiple electrical contacts in the form of contact rings which are spaced along and are flush with a surface of the connector body. Lead connectors may also include a pin contact extending from the proximal end. A conductor typically extends through the lead body from each contact ring and projects from the distal end of the molded body so as to provide a connection point for the conductors of the main lead. Similarly, a main body pin may extend along a central axis of the lead connector from the pin contact at the proximal end and also project from the distal end of the molded body.
Conventional practices for the manufacture of lead connectors include an injection molding process, or a reaction injection molding process, or liquid silicone molding process, or a potting process wherein the ring connectors, conductive pins, and the central pin/pin contact (if being employed) are arranged within a mold cavity. A thermoplastic material, or other suitable material, is then injected into the mold cavity to over-mold the conductive pins, ring connectors, and main body pin to form the cylindrical body of the lead connector.
Tight tolerances are required for the safe and effective performance of lead connectors, including IS4/DF4 connectors. However, the injection molding process presents many challenges and shortcomings that make maintenance of such tight tolerance difficult to meet and which can result in high production costs and low manufacturing yields. For these and other reasons, there is a need for the present embodiments.
In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific examples in which the disclosure may be practiced. It is to be understood that other examples may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims. It is to be understood that features of the various examples described herein may be combined, in part or whole, with each other, unless specifically noted otherwise.
In one embodiment, lead connector 20 includes first-third ring contacts 38a, 38b, 38c, disposed in a spaced-apart fashion along a longitudinal dimension of body 30, and a central pin 40 axially extending from proximal end 32 having a pin contact 42. First-third ring contacts 38a-38c are imbedded in and have a same outer diameter as body 30 so as to provide cylindrical body 30 with a uniform circumferential surface. Body 30 may be formed of an electrically non-conductive polymer material (e.g. polyurethane, polyetheretherketone (PEEK), polysulfone, etc.), epoxy, liquid silicone rubber, or any other suitable type of electrically non-conductive material.
In one embodiment, first-third conductive pins 48a, 48b, and 48c axially extend through body 30 respectively from first-third ring contacts 38a, 38b and 38c, and project from distal end 34 of body 30. In one embodiment, first-third conductive pins 48a-48c are generally rigid wires that form first-third conductive pins 48a-48c. Similarly, central pin 40 extends axially through body 30 and projects from distal end 34, with central pin 40 defining a central lumen 44. In other embodiments, central pin 40 may extend axially through body 30, but project from distal end 34 on the outer periphery, such as with first-third conductive pins 48a-48c.
In one embodiment, lead connector 20 is configured to be coupled to a flexible implantable lead. For example, lead connector 20 can be coupled at its distal end 34 to a flexible implantable lead 50 (illustrated in dashed lines in
In one embodiment, lead connector 20 is configured at its proximal end 32 to be coupled to a device. For example, in one embodiment, lead connector 20 is configured to be inserted into a receptacle or bore of 56 of header of a pulse generator 58 (illustrated in dashed lines in
It is noted that while lead connector 20 has been described with an example primarily in the context of an IS4/DF4 lead connector, one skilled in the art understands that the use of an assembly frame described below, as well as manufacturing techniques described herein, are applicable to other types of lead connectors as well. Accordingly, the features of lead connector 20, including as assembly frame, and methods of manufacture described, herein should not be interpreted as being limited to only IS4/DF4 lead connectors.
In one embodiment, each of first-third conductive pins 48a, 48b, and 48c respectively have proximal ends 46a, 46b, and 46c and distal ends 47a, 47b, and 47b. In one embodiment, the proximal ends 46a, 46b, and 46c are respectively fixed to ring contacts 38a, 38b, 38c, while the distal ends 47a, 47b, and 47b each extend back toward the distal end 34 of lead connector 20.
In one embodiment, first-third ring-pin subassemblies 38a/48a, 38b/48b, 38c/48c are configured for “nesting”, such that first conductive pin 48a extends from its proximal end 46a at first ring 38a back through second and third rings 38b and 38c toward the distal end 34 of lead connector 20. Similarly, second conductive pin 48b extends from its proximal end 46b at second ring 38b back through third ring 38c toward the distal end 34 of lead connector 20. Third conductive pin 48c extends from its proximal end 46c at third ring 38c back toward the distal end 34 of lead connector 20. In one embodiment, central pin 40 is also arranged so as to extend through all three ring contacts 38a-38c from proximal end 32 to distal end 34.
In one embodiment, it is important that conductive pins extending through rings to which they are not coupled do not inadvertently make contact with these rings. For example, while first conductive pin 48a is coupled to first ring 38a, it cannot make contact with second and third rings 38b and 38c as it extends toward the distal end 34 of lead connector 20. Touching another ring can cause an electrical short. Even getting too near a ring can leave the device susceptibility to electrical arcing.
In some designs, an insulative coating is added to each conductive pin or wire and it extends through adjacent rings in order to avoid inadvertant electrical contact with rings. Similarly, an insulating sleeve can be added to each wire or pin. Both processes, however, add complexity and cost to the manufacturing of a lead connector. For example, a coated wire must be ablated on each of the proximal and distal ends to provide electrical conductivity where it is needed (at connection points). Furthermore, adding individual insulating tubing to each wire is time consuming and adds multiple parts. All of this adds to manufacturing time and cost.
In one embodiment, during the assembly of lead connector 20, each first-third ring-pin subassemblies 38a/48a, 38b/48b, 38c/48c are individually assembled onto assembly frame 60 to form a ring-pin assembly 70.
In one embodiment, third ring-pin subassembly 38c/48c is placed over assembly frame 60 by sliding third conductive pin 48c into third opening 68c (not visible in
In one embodiment, assembly frame 60 is configured with first-third steps 62a, 62b and 62c being spaced along its longitudinal dimension such that when a respective ring 38a-48c is placed adjacent the step, the ring will be situated in a desired longitudinal location relative to the final lead connector 20. The longitudinal spaces between steps can be adjusted and tailored to any particular application or standard to ensure proper spacing between rings. Similarly, first-fourth openings 68a, 68b, 68c, and 68d are configured to ensure that respective conductive pins 48a, 48b, 48c, and 48d are located properly to ensure conductive contact with appropriate rings and avoid inadvertent contact with the other rings and other conductors.
In one embodiment, first-third openings 68a, 68b, 68c, and thus, first-third conductive pins 48a, 48b, 48c, are arranged generally on the outer perimeter of assembly frame 60, such as viewed from the end illustrated in
In one embodiment, once first-third ring-pin subassemblies 38a/48a, 38b/48b, 38c/48c are individually placed on to assembly frame 60, the combined ring-pin assembly 70, illustrated in
In one embodiment, assembly frame 60 obviates the need for an assembly operator to carefully load each ring-pin subassembly into the mold cavity 82 and to carefully position them to ensure proper spacing and alignment. Traditional manufacturing process requires that each ring-pin subassembly must be nested and inserted individually into the mold tool, such that each ring and each conductor is precisely located to ensure proper spacing, thereby requiring skill and extra time during the assembly process.
After ring-pin assembly 70 is loaded into mold cavity 82, mold material is injected into mold cavity 82 to over-mold those portions of ring-pin assembly 70 within mold cavity 82 and form connector body 30. After removal from the mold cavity, assembly frame 60 is integral with body 30 and forms a portion of the finished lead connector 20. The resulting finished lead connector 20 (as illustrated by
In one embodiment, assembly frame 60 is made of a material that is the same as the mold material injected into mold cavity 82. Since the mold material flows in hot, some or all portions of assembly frame 60 may melt and mix with the injected mold material. In other embodiments, assembly frame 60 is made of a material that is the different than the mold material injected into mold cavity 82. For example the materials may have different durometers and/or meting points, such that in some circumstances, the material of assembly frame 60 will remain relatively intact, but fully surrounded by the molding material in the final lead connector 20.
In one embodiment, the rigid structure of assembly frame 60, combined with a secure fit of first-third conductive pins 48a, 48b, 48c with first-third openings 68a, 68b, 68c, prevents the forces of mold material injected into the mold cavity 82 from moving and misaligning conductive pins 48a, 48b, 48c and rings 38a, 38b, 38c. In traditional manufacturing process, the ring-pin subassemblies are free-standing during molding. High injection pressure used in the injection molding process can cause the conductive pins and central pin to move within the mold cavity, thereby causing the electrical characteristics to potentially vary between lead connectors, and even causing shorting issues should the conductive pins be moved into contact with one another or other conductive elements within the lead connector. Forces created inside the mold cavity subject the pins to potential movement and bowing (forcing curvature) during the molding process. For example, during traditional manufacturing process, there are opportunities for electrical shorts or arcing between conductor paths. During the nesting process and the molding process it is imperative that the pin from one ring does not touch or come too near another ring or pin. Assembly frame 60 ensures such faults are avoided.
At 106, the ring-pin sub-assemblies are arranged onto the assembly frame to form a ring-pin assembly. For example, according to one embodiment as illustrated by
At 108, the ring-pin assembly, such as ring-pin assembly 70, is loaded into a mold cavity of an injection molding system, such as mold cavity 82 of molding system 80 (see
At 112, the finished lead connector, such as lead connector 20, is removed from the mold. At 114, if required, post mold secondary processing is performed, such as annealing, plasma treatment, machining, trimming or cleaning. For example, some thermoplastics require annealing in order to meet dimensional specification. Machining can be done to add a feature on an inner diameter or outer diameter of the lead connector that cannot be effectively formed via injection molding.
Also, whereas assembly frame 60 illustrated in previous embodiments had 3 openings around its perimeter and 3 steps spaced along its length, assembly frame 160 has 6 openings around its perimeter and 6 steps spaced along its length. In this way, assembly frame 160 can accommodate 6 ring-pin subassemblies, ensuring proper spacing between each ring and between each conductor in the ring-pin assemblies. Like assembly frame 60, assembly frame 160 can also be provided with a center opening to accommodate a center pin or other center conductor or the like. As is evident to one skilled in the art, an assembly frame can have any number of steps and openings to accommodate any number of ring-pin subassemblies.
In one embodiment, central pin 40 is inserted through seventh opening 268g so that it extends out of assembly frame 360 at both its ends. Once fully assembled, the ring-pin assembly is placed in a mold cavity and overmolded into a lead connector as previously described.
In the illustrated assembly frame 460, first-fourth openings 468a, 468b, 468c, and 468d are configure as slots, with a longitudinally extending narrow slot-opening along the length of each opening. Configuring first-fourth openings 468a, 468b, 468c, and 468d as slots can be useful in assembling the pins and may have advantages in tooling in some embodiments. Once assembly frame 460 has respective conductive pins assembled into openings 468a, 468b, 468c, and 468d and rings assembled adjacent first-fourth steps 462a, 462b, 462c and 462d, it can be overmolded as described above for the other ring-pin assemblies, such that molded material will flow over and into the slots, completely surrounding the conductive pins.
Although specific examples have been illustrated and described herein, a variety of alternate and/or equivalent implementations may be substituted for the specific examples shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific examples discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.
This Non-Provisional Patent application claims the benefit of the filing date of U.S. Provisional Patent Application Ser. No. 63/057,033, filed Jul. 27, 2020, ENTITLED “LEAD CONNECTOR WITH ASSEMBLY FRAME AND METHOD OF MANUFACTURE,” which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63057033 | Jul 2020 | US |
