Cylindrical electrical connector and its manufacturing process

Abstract

An electrical connector has a body (3) of substantially cylindrical shape extending in a principal direction (F). It comprises a plurality of contact rings (1) distributed along the principal direction (F) on the surface of the body (3), and for each contact zone, a wire (4) passing through the body (3), the set of wires (4) forming a bundle oriented towards one end of the body (3). The body (3) is made of a tubular sheath (3) of an elastomeric material, each wire (4) extending in a central cavity (30) of the sheath (3) and passing through the wall to one of the contact rings (1) via an incision (31) through the wall of the sheath (3). Method of manufacturing the connector and its use for the transmission of electrophysiological signals. Figure for the abstract: Fig. 3

Description

Title of the invention: Cylindrical electrical connector and its manufacturing process. Technical field

[0001] The invention relates to a cylindrical electrical connector, particularly for connecting intracerebral electrodes. It also relates to the manufacturing process of the connector. Previous technique

[0002] Document FR 2 841 689 A1 shows a multi-contact connector suitable for use with medical electrodes. The connector comprises a male and a female part. The male part extends axially in an elongated shape with contacts distributed along this axial direction. The contacts are riveted metal strips, with conductors welded to the rivets. This arrangement has the disadvantage that the conductors are poorly protected.

[0003] US2021184414A1 shows a connector comprising an alignment of metal rings connected to wires extending inside the rings. The insulating portion is produced by injecting synthetic material into a mold in which the rings are placed. Although the conductors are better protected, their placement is delicate. Indeed, the entire assembly of rings and conductors is placed in the closed mold, and nothing allows for properly holding this assembly in place during the injection of molten material. Furthermore, it is necessary to manufacture a specific injection mold. Description of the invention

[0004] It is therefore an objective of the invention to provide a cylindrical electrical connector that can be constructed simply and reliably.

[0005] With these objectives in view, the invention relates to an electrical connector having a substantially cylindrical body extending in a main direction, the connector comprising a plurality of conductive contact rings distributed along the main direction on the surface of the body, and for each contact area a wire passing through the body, the set of wires forming a bundle oriented towards one end of the body, characterized in that the body is made with a tubular sheath of an elastomeric material, each wire extending in a central cavity of the sheath and passing through the wall towards one of the contact rings by means of an incision through the wall of the sheath.

[0006] Thanks to these arrangements, the connector can be manufactured without significant technical resources, in particular without a mold. The conductors are well protected inside. The sheath ensures that the distance between the wires and the surface is guaranteed by the sheath wall thickness. The connector remains flexible due to the sheath's flexibility, allowing for contact even if a female part has misalignment.

[0007] According to one embodiment, the wire has a winding of more than one turn around the outside of the sheath, the winding being underlying the corresponding contact ring to establish electrical contact between the wire and the ring. A simple means is provided for establishing contact between the ring and the conductor. The embodiments have shown that electrical continuity is obtained reliably and satisfactorily.

[0008] According to an improvement, the sheath is filled with a sealant that encapsulates the bundle. The conductors are thus protected against the insertion of moisture or foreign bodies. In addition, they are immobilized relative to each other by the sealant.

[0009] According to one provision, the sealant is a silicone elastomer. The flexibility of the connector is preserved.

[0010] According to one provision, the sheath is made of silicone elastomer.

[0011] According to one provision, the rings are made of stainless steel.

[0012] According to one arrangement, the conducting wires are made of platinum and iridium alloy.

[0013] According to one provision, the thickness of the rings is between 2 and 10% of the outer diameter of said rings.

[0014] The invention also relates to a method for manufacturing a connector as described above, in which an elastomer sheath is prepared, and for each wire, a through-cut is made through the wall of the sheath. A wire feeder is used to insert the wire so that it extends on both sides of the wall. Thus, one can start with a standard sheath and add the conductor wires by creating the cuts at the desired locations and passing the wires through them.

[0015] According to an improvement, the portion of the wire protruding outside the sheath is stripped, the stripped portion is wound around the sheath to form a coil, and the corresponding ring is slid in the main direction to cover the coil with the ring. Electrical continuity is thus established in a very simple manner.

[0016] In one step, a polymerizable sealant is injected into the central cavity to coat the bundle of wires. The sealant is put in place while malleable, then hardened, for example by polymerization.

[0017] The invention also relates to the use of a connector as defined above for the transmission of electrophysiological signals. It has been verified that this connector transmits this type of signal without loss of information. Brief description of the figures

[0018] The invention will be better understood and other features and advantages will become apparent upon reading the following description, the description referring to the accompanying drawings, among which: • [Fig.1] is a view of a sheath used for the manufacture of a connector according to an embodiment of the invention; • [Fig.2] is a view of an intermediate manufacturing phase of the connector; • [Fig.3] is a perspective view of the connector according to the first embodiment; • [Fig.4] is a cross-sectional view showing the passage of a conductor through the sheath; • [Fig.5] is a schematic view of a test setup to validate the quality of the connector. Detailed description

[0019] An electrical connector according to the invention is shown in Figures 1 to 4. The connector has a substantially cylindrical body 3 extending in a principal direction F. The connector comprises a plurality of rings 1 forming contact areas distributed along the principal direction F on the surface of the body 3, as shown in [Fig. 3]. The body is made with a tubular sheath 3 of an elastomeric material, such as a silicone elastomer. Its hardness is, for example, 80 Shore A.

[0020] The sheath 3 has for example a diameter of 1.5 mm and a wall thickness of 0.2 mm.

[0021] The rings 1 are made of conductive metal such as stainless steel, by example of type 304L or 316L. The wall thickness of ring 1 is for example 0.1 mm.

[0022] For each ring 1, a wire 4 has several turns 40 around the sheath 3 to form a winding, the turns 40 being in contact with the inner surface of the ring 1 to establish electrical contact between the wire 4 and the ring 1. The wire of the turns 40 is stripped while the rest of the wire 4 is protected by a layer of electrical insulation. The wire 4 passes through a through incision through the wall of the sheath 3, then extends inside a central cavity 30 of the sheath 3 until it exits the body 3. The set of wires 4 forms a bundle oriented towards one end of the body 3 of the central cavity 30 of the sheath 3 and passing through the wall towards one of the contact rings 1 by means of an incision 31 through the wall of the sheath 3. The conductive wires 4 are made of platinum and iridium alloy, for example with a proportion of 90-10%.

[0023] The cavity 30 of the sheath 3 is filled with a sealant encompassing the bundle of wires 4. The sealant is, for example, a silicone elastomer.

[0024] To manufacture a connector according to the invention, the following steps are carried out.

[0025] First, a sheath 3 of elastomer of the chosen diameter is supplied and a part of this sheath 3 is cut with a straight cut 32 on one side and a bevel cut 33 on the other. The bevel cut 33 is made at an angle of approximately 25° to the axis of the sheath 3. The rings 1 are then inserted through the bevel cut end 33 and the rings 1 are distributed at regular intervals. Next to each ring 1, an incision 31 is made through the wall of the sheath 3, then a thread guide is used to introduce the wire 4 so that it extends on both sides of the wall and exits at the straight cut end 32 of the sheath 3. The part of the wire 4 that protrudes outside the sheath 3 is stripped, and the stripped part is wound around said sheath 3 to form the winding of turns 40. The ring 1 corresponding to each wire 4 is slid in the main direction F to cover the turns 40 with the ring 1.Finally, a polymerizable sealant is injected into the central cavity 30 of the sheath 3 to encapsulate the wire bundle 4. The wire bundle 4 exiting the sheath 3 is then connected to another connector, in a manner not detailed here. The beveled end 33 is finally cut by a straight cut 34, at a predetermined distance from the first ring 1.

[0026] Experimentation

[0027] The present invention is intended to allow the transfer of electrophysiological signals between a recording electrode 5 and a preamplifier 6.

[0028] The electrophysiological characteristics to be transmitted may be of a different nature: • Local electric field potentials (LFP), with a frequency between 1 and 500 Hz and an amplitude of approximately 2,000 pV; • Single or Multi Unit Action potentials (S / MUA), with a frequency less than 0.3 kHz or greater than 3 kHz and an amplitude of approximately 200 pV.

[0029] In order to test the electrical transfer qualities of the connector according to the invention, an experimental test bench was implemented, as shown in [Fig. 5], to evaluate the quality of the transmitted electrical signals, by comparison with a direct transfer of the signals directly to the preamplifier. A realistic electrophysiological signal simulator 7, generating either local electric field potentials or unit action potentials, was used. The signal provided by the simulator 7 was connected on one side to the preamplifier 6 and on the other side to a test tube 8 containing physiological medium. A recording electrode 5 was connected to a stimulation electrode 8 placed in a physiological medium, the electrode 5 being connected to a female connector 9. A male connector according to the invention was inserted into the female connector 9, its output being connected to the preamplifier 6, which sends the signals to a converter 60.

[0030] Simulator 7 was operated to generate signals simulating local electric field potentials for two minutes. The signals originating either directly from simulator 7 or from electrode 5 were compared. The electrical noise level was found to be comparable. Furthermore, an identical voltage level was observed with no time lag, i.e., no phase shift between the signals and no distortion between the signals.

[0031] Simulator 7 was also driven to generate signals simulating unitary action potentials for two minutes. These signals contain numerous peaks, both upward and downward. The signals originating directly from simulator 7 and from electrode 5 were compared. The number of peaks was determined by applying a high threshold and a low threshold. For both measurements, a substantially equivalent number of peaks was observed. Furthermore, a strong similarity was observed in the amplitude, duration, and morphology of the peaks. It was therefore concluded that the connector according to the invention was suitable for use in transmitting electrophysiological signals.

[0032] The invention is not limited to the embodiment described by way of example. Other materials may be used for the sheath 3, the wires 4, or the rings 1. For example, stainless steel, gold-plated copper, or tungsten may be used for the wire. Platinum, 304L steel, a platinum / iridium alloy, or gold-plated copper may be used for the rings. A thermoplastic such as polypropylene, polyethylene, or polyamide may be used for the sheath. The connection between the ring and the wire could be made by filler welding, by heat compression welding, or by bonding with a conductive adhesive.

Claims

Demands

1. Electrical connector having a body (3) of substantially cylindrical shape and extending in a principal direction (F), the connector comprising a plurality of conductive contact rings (1) distributed along the principal direction (F) on the surface of the body (3), and for each contact area a wire (4) passing through the body (3), the set of wires (4) forming a bundle oriented towards one end of the body (3), characterized in that the body (3) is made with a tubular sheath (3) of an elastomeric material, each wire (4) extending in a central cavity (30) of the sheath (3) and passing through the wall towards one of the contact rings (1) by means of an incision (31) through the wall of the sheath (3).

2. Connector according to claim 1, wherein the wire (4) has a winding of more than one turn around the outside of the sheath (3), the winding (40) being underlying the corresponding contact ring (1) to establish electrical contact between the wire (4) and the ring (1).

3. Connector according to any one of the preceding claims, wherein the sheath (3) is filled with a sealant enclosing the bundle.

4. Connector according to claim 3, wherein the sealant is a silicone elastomer.

5. Connector according to any one of the preceding claims, wherein the sheath (3) is made of silicone elastomer.

6. Connector according to any one of the preceding claims, wherein the rings (1) are made of stainless steel.

7. Connector according to any one of the preceding claims, wherein the conducting wires (4) are made of platinum and iridium alloy.

8. Connector according to any one of the preceding claims, wherein the thickness of the rings (1) is between 2 and 10% of the outside diameter of said rings (1).

9. A method for manufacturing a connector according to any one of the preceding claims, wherein a sheath (3) is prepared out of elastomer, and for each wire (4), a through incision (31) is made through the wall of the sheath (3), a wire feeder is used to introduce the wire (4) so ​​that it extends on both sides of the wall.

10. A method according to claim 9, wherein the part of the wire (4) which protrudes outside the sheath (3) is stripped, the stripped part is wound around said sheath (3) to form a winding, and the corresponding ring (1) is slid in the main direction (F) to cover the winding with the ring (1).

11. Method according to claim 9 or 10, wherein a polymerizable sealant is injected into the central cavity (30) to coat the bundle of wires (4).

12. Use of a connector according to any one of claims 1 to 8, for the transmission of electrophysiological signals.

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