In-line connector stack with testing capability

0001The invention relates to a method for manufacturing an in-line connector according to the preamble of claim 1 and to a connector header assembly according to the preamble of claim 11.

0002<patcit id="pcit0001" dnum="US2009048638A1"><text>US 2009/048638 A1</text></patcit> discloses a connector assembly for use with implantable medical devices which connector assembly is generally formed by coupling a plurality of contact housings, sealing rings and leaf spring contact elements to form a connector having a common bore for receiving a medical lead cable Contact grooves for positioning the leaf spring contact elements are formed in part by assembling multiple components together

0003<patcit id="pcit0002" dnum="US2007202728A1"><text>US 2007/202728 A1</text></patcit> discloses a medical device connector assembly wherein the connector assembly includes a core element, a plurality of conductive members positioned along the core element and a plurality of sealing members positioned between the conductive members wherein the sealing members having an outer surface supported by the core element A single end cap which frictionally slides into engagement with the core element and a set screw block on the opposite end is provided.

0004Implantable medical devices for providing electrical stimulation to body tissues, for monitoring physiologic conditions, and for providing alternative treatments to drugs are well known in the art. Exemplary implantable medical devices include implantable cardio defibrillators, pacemakers, and programmable neurostimulator pulse generators, which are collectively herein referred to as "implantable medical devices" or IMDs. These IMDs typically incorporate a hermetically sealed device enclosing a power source and electronic circuitry. Connected to the sealed housing, also known as a "can," is a header assembly. The header assembly includes electrical contact elements that are electrically coupled to the electronic circuits or to the power source located inside the can via conductive terminals. The header assembly provides a means for electrically communicating, via an external medical lead cable, the electronic circuits or power source located inside the device with the actual stimulation point

0005Industry wide standards have been adopted for, among other things, the dimensions, size, pin spacing, diameter, etc for the receptacle and the medical lead cable Furthermore, good electrical contact must be maintained during the life of the implantable medical device and the medical lead cable for use with the IMD must not disconnect from the receptacle located in the header, yet be detachable for implanting and programming purposes and for replacing the IMD when necessary.

0006Although prior art connector contacts provide viable options for medical device manufacturers, the IMD discussed herein and the various headers provide many benefits to manufacturers and practitioners. Furthermore, in-line connectors, while discussed with specific implantable applications, may be used in other industries and applications, including consumer electronics, electrical connectors, and industrial electronics, such as aviation, automotive, oil and gas, etc.

0007The invention comprises the features in the characterising part of claims 1 and 11.

0008Broadly speaking, in-line connector stacks are disclosed Examples include in-line connector stacks placed inside an encapsulation layer so that the encapsulated stack may be tested for aligning and conductivity before it is installed or placed into a header of an IMD. Different in-line connector stacks comprising different seal and conductive elements may be used with the encapsulation layer concept of the present application. Furthermore, while the specification describes specific applications of the connector stacks in combination with a header of an IMD, the stacks may be used in other applications and industries requiring multiple conductive sources in an in-line configuration.

0009An exemplary method is directed to a method for manufacturing an in-line connector. In one specific example, the method comprising encapsulating an in-line connector stack comprising a common bore with an encapsulation layer to form an encapsulated stack comprising two end surfaces; wherein a plurality of seal elements and conductive contact elements are located between the two end surfaces; aligning a plurality of slots formed on the encapsulation layer with the plurality of conductive contact elements; placing two end caps at the two end surfaces of the encapsulation layer to retain the plurality of seal elements and conductive contact elements inside the encapsulation layer; and wherein the encapsulated stack comprises a common bore and two end openings.

0010An exemplary apparatus comprises a header assembly comprising a header comprising a bore, an in-line connector stack comprising a plurality alternating seal elements and conductive contact elements encapsulated by an encapsulation layer positioned inside the bore, and a snap fit end cap comprising a bore mechanically engaged to the header, which defines a seam therebetween, and wherein the header comprises a plurality of slots aligned with a plurality of slots formed on the encapsulation layer

BRIEF DESCRIPTION OF THE DRAWINGS

0011The following drawings form part of the present specification and are included to further demonstrate certain aspects of the disclosed IMDs, connector stacks, and headers. The present embodiments may be better understood by one or more of these drawings in combination with the detailed description of examples presented herein. <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">FIGs. 1A, 2A, 3A</figref>, <figref idref="f0002">4A, 5A, 6A, and 7A</figref> show an in-line connector stack of alternating conductive and non-conductive elements, an encapsulation layer for receiving the in-line connector stack, a header for receiving the encapsulated stack, and a sealed electronic case for mating with the header.</li><li><figref idref="f0003">FIGs. 1B</figref>, <figref idref="f0004">2B</figref>, and <figref idref="f0005">3B</figref> show a header comprising two in-line connector stacks, which are positioned in respective encapsulation layers.</li><li><figref idref="f0006">FIGs 4B</figref>, <figref idref="f0007">5B</figref>, and <figref idref="f0008">6B</figref> show a header attached to an electronic case comprising an encapsulated in-line stack and an integrated snap fit end cap comprising a holding ring.</li><li><figref idref="f0009">FIG. 8</figref> is a cross-sectional side view of the header of <figref idref="f0002">FIG. 4A</figref>.</li><li><figref idref="f0010">FIG. 9</figref> is a semi-schematic perspective view of the header of <figref idref="f0006">FIG. 4B</figref> attached to a sealed electronic housing.</li><li><figref idref="f0011">FIG. 10</figref> is a semi-schematic partial cross-sectional side view of the device of <figref idref="f0010">FIG. 9</figref>.</li><li><figref idref="f0012">FIG. 11</figref> is a semi-schematic cross-sectional side view of an alternative encapsulated stack.</li></ul>

DETAILED DESCRIPTION

0012The detailed description set forth below in connection with the appended drawings is intended as a description of the presently preferred embodiments of apparatus and method for making and using IMDs, in-line connector stacks, and headers and is not intended to represent the only forms in which they may be constructed or utilized. The description sets forth the features and the steps for constructing and using the IMDs, in-line connector stacks, and headers of the present examples in connection with the illustrated embodiments. It is to be understood, however, that the same functions and structures may be accomplished by different embodiments that are also intended to be encompassed within the scope of the claims. As denoted elsewhere herein, like element numbers are intended to indicate like or similar elements or features.

0013<figref idref="f0001 f0002">FIG. 1A to FIG. 7A</figref> show a stackable connector in various stages of assembly and different views for clarity. The connector stack 10, which comprises a plurality of seal elements 50, conductive elements 52, and spring contact elements 54, is configured to fit inside an encapsulation layer 12 to form an encapsulated stack 14. The encapsulated stack 14 is configured to fit inside a molded header 16, which has slots 56 or openings for accessing to weld the leads 58 from the electronic case (See, e.g., <figref idref="f0002">FIG. 7A</figref> and <figref idref="f0007">5B</figref>) with the conductive elements 54. The openings 56 are then back filled with a curable implantable material, such as silicone and other medical grade elastomers or resins. Another opening 56.1 may be provided for inserting a holding ring 60 with a locking screw 60.1 for more permanently securing the lead cable 44 to the connector stack, as shown in <figref idref="f0002">FIG. 6A</figref>. In one embodiment, end caps 15 are incorporated, either at only one end of the stack 10 or at both ends, as shown in <figref idref="f0001">FIG. 1A</figref> in exploded view. The end caps 15 are positioned adjacent an end seal element 50.1 and provide engagement with the encapsulation layer 12. In one example, the end caps 15 provide added sealing by incorporating interior ribs or rings for sealing against the electrical lead cable 44. The end caps 15 may have the same or higher durometer as the seal element but may be lower to facilitate insertion at the inlet. The end seal element 50.1 may be similar to the middle seal elements but also includes sealing means, such as ribs and projections, for sealing against the end cap.

0014As shown, the encapsulation layer 12 comprises a generally cylindrical tube comprising one or more slots 64. In one example, the number of slots 64 corresponds to the number of conductive contact elements 52, which can vary depending on the desired applications and electrical contacts. The encapsulation layer 12 comprises a lip 74 at each end for engaging the end cap 15. As shown, the in-line stack 10 comprises three conductive elements. However, less than or more than three may be incorporated without deviating from the scope of the present invention. When installed into the header 16, the slots 64 on the insulation layer 12 align with the slots 56 on the header 16 so that leads 58 from the can 22 may be accessed and attached to the conductive elements 52.

0015Thus, a feature of the present assembly and method for making an IMD, in-line stack, and header is understood to include a plurality of alternating seal elements 50 and conductive elements 52 located inside an encapsulation layer 12 comprising a plurality of slots 64, and wherein the plurality of slots align with a corresponding number of conductive elements 52. According to the invention, a canted coil spring 54 is in electrical contact with each conductive element 52. As shown in <figref idref="f0001">FIG. 2A</figref>, the canted coil spring 54 is located within a groove 66 formed along the inside bore 68 of the in-line stack, which is common with the bore 62 of the header 16. In a particular embodiment, the groove 66 is formed utilizing a back wall and a side wall of a conductive contact element 52 along with a side wall of an adjacent seal element 50. However, the groove 66 may be formed using different features and walls utilizing different conductive rings and seals than as shown, such as that shown in <figref idref="f0012">FIG. 11</figref>, further discussed below. Signals or current passing from the leads 58 (<figref idref="f0001">FIG. 3A</figref>) of an electrical housing or case are configured to pass through corresponding conductive elements 52 which then pass through corresponding springs 54 and to corresponding electrode ring terminals 70 on the lead cable 44, which then pass through corresponding electrode leads 72 (<figref idref="f0002">FIG. 6A</figref>).

0016According to the invention, a snap fit end cap 18 is incorporated for securing the encapsulated stack 14 inside the header bore 62 of the header 16, as shown in <figref idref="f0001 f0002">FIGs. 3A-5A</figref>. The snap fit end cap 18 has provisions for engaging the header 16 and for providing an axial force on the encapsulated stack 14 to at least slightly compress the stack inside the header. For example, the snap fit end cap 18 and the header 16 may incorporate interference detent arrangements that snap in place utilizing axial interference. A seam is defined between the end cap 18 and the header 16, which is sealed by the force or pressure of the snap fit arrangement. In another example, curable implantable material is applied to further seal the seam. As shown, one or more raised bumps or ribs 36.1 are incorporated in the bore of the end cap 18 for sealing against the exterior surface of a lead cable. The one or more raised bumps or ribs 36.1 would provide additional sealing from potential leakage into the bore of the in-line stack in addition the seal elements.

0017By stacking the connector stack 10 into an encapsulation layer 12 and encapsulating it as a stack unit 14, the stack is aligned and can optionally be tested before placing the stack 14 into the header. In other words, the encapsulated stack unit 14 may be viewed a free-standing axially compressed stack that is aligned and adapted to receive an electrical lead cable 44 (<figref idref="f0002">FIGs. 6A and 7A</figref>). Thus, a technician can better perform quality control on the stack 14 before placing it into a header 16 or into a connector housing and then molding it in place with resin. Previously, a technician can only test the stack after it has been assembled onto the electrical case 22 (<figref idref="f0002">FIG. 7A</figref>), which can only be done by installing the same into a header 16. For example, a technician can test the stack unit 14 as shown in <figref idref="f0001">FIG. 2A</figref> by inserting a lead cable into the stack bore 68 and applying signals or current through the slots 64 to electrically communicate with the aligned conductive elements 52. As such, the in-line connector stack 14 has utility independent of being placed into the header 16 and/or for use with an implantable device.

0018Refer again to <figref idref="f0001">FIG. 1A</figref>, the encapsulation layer 12 may be made from thermoplastic or TPE material and preferably non-conductive. In one example, the encapsulation layer is made from a thermoset plastic and comprises a generally cylindrical shape structure comprising slots 64 and end lips 74 for retaining or engaging the end caps 15.

0019In an alternative embodiment, a locking ring with a locking screw is incorporated in the snap fit end cap 18 (<figref idref="f0006">FIG. 4B</figref>) for securing the lead cable.

0020In an alternative embodiment, the end cap 18 is integrally formed with the header 16 and a rear opening (not shown) is instead incorporated on the header, near element 20 of <figref idref="f0002">FIG. 5A</figref>. In this alternative embodiment, the stack unit 14 would be installed through the rear opening, which is subsequently back filled with a curable resin.

0021In an alternative embodiment, the encapsulated stack 14 is over molded with a polymeric header casting resin instead of being inserted into the pre-formed header 16 as shown. The over molded header in this alternative embodiment, not including the pre-formed header 16, is then attached to an electronic case, i.e., sealed can, of an implantable medical device 22.

0022<figref idref="f0003 f0004 f0005">FIGs. 1B to 3B</figref> show yet another alternative header assembly 24 comprising a double bore arrangement 26a, 26b. Each bore is configured to store an encapsulated stack 14, similar to the embodiment of <figref idref="f0001 f0002">FIGs. 1A to 7A</figref>, and has a snap fit end cap 18 for retaining the stack 14 inside the bore. In one embodiment, a center rib 28 incorporates two detents in superjacent format. The two detents in superjacent format are configured for snap fit engagement with the end caps 18.

0023In an alternative embodiment, the header 24 is configured to receive the two connector stacks 14 in a side-by-side configuration instead of one on top of another as shown in <figref idref="f0004">FIG. 2B</figref>. In other embodiments, more than two connector stacks 14 may be incorporated into the header 24 in a side-by-side configuration, one on top of another configuration, or a pyramid type configuration.

0024Referring now to <figref idref="f0006 f0007 f0008">FIGs. 4B to 6B</figref>, a set screw block 30 having a set screw 32 is incorporated in the snap fit end cap 34. An opening 34.3 is thus provided on a side of the frustoconical cone section of the end cap 34 to provide access to the set screw 32. The opening 34.3 may be back-filled with an implantable material or resin after the set screw 32 is turned to tighten against the lead cable 44 (<figref idref="f0007">FIG. 5B</figref>). The sect screw block 30 may be made from a plastic material and co-molded with the snap fit end cap 34. In one embodiment, seal elements 36 having annular seal ribs are co-molded or over-molded with the end cap 34 for sealing against a lead cable. The seal elements 36 may be made from the same material as the seal elements 50, which may be an elastomer or a thermoplastic elastomer (TPE), and inserted into the end cap 34.

0025In an alternative embodiment, the end cap 34 is integrally molded with the header 24 and the header is provided with a rear opening, near element 20 (<figref idref="f0007">FIG. 5B</figref>). The encapsulated stack 14 may be placed into the bore of the header through the rear opening. The opening may then be back filled with an implantable material. A snap fit cap or flange (not shown) may also be used to close the rear opening instead of simply back filling the rear opening with a resin. The snap fit cap or flange may be use by itself to seal the rear opening or in combination with curable resin.

0026Also shown in the perspective transparent view <figref idref="f0006">FIG. 4B</figref> are three windows or slots 56 for accessing the leads 58 from the electrical case (not shown), such as a sealed can of an IMD. The windows are understood to be backfilled with an implantable material or resin after the leads are secured to the conductive ring contact elements.

0027Also shown in the perspective view of <figref idref="f0006">FIG. 4B</figref> is a set screw opening on the snap fit end cap 34. As such, an opening on the header for a separate holding ring with set screw may be eliminated.

0028Also shown in the cut-away perspective view of <figref idref="f0007">FIG. 5B</figref> is an assembled implantable medical device 22 with a lead cable 44 inserted into the common bore of the encapsulated stack 14. The implantable medical device 80 may be any number of devices, such as an implantable cardio defibrillator, pacemaker, and programmable neuro-stimulator pulse generator, to name a few.

0029Also shown in the cut-away perspective view of <figref idref="f0008">FIG. 6B</figref> are a set screw block 30 and two seal inserts 36. In one example, the snap fit end cap 34 is made from a plastic material and is molded with at least one groove 82 for receiving the relatively softer sealing ring 36 comprising raised bumps or ribs 36.1, such as made from silicone or a TPE material, which is separately formed and installed into the groove 82. In another embodiment, the components are co-molded.

0030<figref idref="f0009">FIG. 8</figref> is an enlarged cross-sectional side view of an exemplary header assembly, which is similar to that shown in <figref idref="f0001">FIGs. 1A</figref> and <figref idref="f0004">2B</figref>. The snap fit end cap 18 is provided with an annular lip seal 40 near the mating end and near the inlet or entrance to the bore of the end cap.

0031<figref idref="f0010">FIG. 9</figref> is a perspective semi-transparent view of the assembly of <figref idref="f0006">FIG. 4B</figref> attached to an electronic case 80.

0032<figref idref="f0011">FIG. 10</figref> is a cross-sectional side view of the assembly of <figref idref="f0010">FIG. 9</figref>.

0033<figref idref="f0012">FIG. 11</figref> is a cross-sectional side view of an encapsulated stack 90 provided in accordance with alternative embodiments, which comprises an in-line stack 92 positioned inside an encapsulation layer 94. Also shown are conductive energizers 96, which separately sit in grooves 98 formed by a conductive element 100 and two adjacent seal elements 102. Note that the conductive elements 100 do not include side walls. As such, the grooves 98 are each formed by a conductive element 100 and two adjacent seal elements 102. The seal elements are each shown with a single projection or lip 104 for sealing against a lead cable. In other embodiments, two or more lips 104 may be incorporated. In the various examples disclosed herein, an encapsulated stack comprising an in-line stack positioned in side an encapsulation layer is provided, which have slots or openings formed on the side thereof for aligning with respective conductive elements. The encapsulated stack, which may be sized to fit any number of contacts as required for a particular application, is configured to facilitate assembly and testing before the encapsulated stack is completed inside a header, connector, or other in-line assembly.

0034Although limited preferred embodiments and methods for making and using connector assemblies provided in accordance with aspects of the present invention have been specifically described and illustrated, many modifications and variations will be apparent to those skilled in the art. For example, various material changes may be used, incorporating different mechanical engagement means to attach the various components to one another, making use of two or more different materials or composites, making a sealing ring from multiple pieces rather than a singularly molded piece, etc. Still alternatively, the connector assembly may be used for any device that requires an in-line connection in which multiple conductive sources are to be relayed between a source generator and a source receiver, whether that device is configured for implanting or otherwise. Still furthermore, although thermoset and thermoplastic polymers are described for encapsulating a stack, other means may be used, such as a mechanical clamp. Also, aspects and features discussed for one embodiment may be used with other embodiments provided the combined embodiment is compatible. Accordingly, it is to be understood that the connector assemblies constructed according to principles of this invention may be embodied in other than as specifically described herein. The invention is also defined in the following claims.