FEMALE CONNECTOR WITH WIPER DEVICE

Abstract: A female connector (2), for cooperative engagement with a male connector (3), is equipped with a flexible wiper device (20) of annular shape. The wiper device receives the male connector through its central opening, which is slightly smaller than the cross section of the male connector. When passing the male connector through the opening, contaminants present on the male connector is wiped away before the male connector enters into electrical contact with the female connector.

Description: Female connector with wiper device The present invention concerns a female connector for a guide wire. More specifically, the invention concerns a female electrical connector adapted to cooperate with a corresponding male connector to prevent contaminants on the male connector to enter into the female connector. Guide wires are generally known in the art. In use, a guide wire is typically introduced into the femoral artery and is then positioned at the desired area. With the guide wire positioned, a catheter may be introduced over the guide wire. To permit a change of catheter, it is desirable to provide a connector at the proximal end of the guide wire. An example of a guide wire assembly with connectors is shown in U.S. Patent No. 5, 178,159 to Christian. However, such a connector may be contaminated by bodily fluids at the time the catheter is changed, which may result in malfunction such as reduced electrical contact between male and female parts of the connector or short circuit between different conductive areas of the male connector. Considering the very small electrical potentials that are at hand it is easily understood that even minute amounts of contamination on the conductive areas have a noticeable impact on the measured values obtained, and may even give rise to erroneous diagnoses. For example, when utilizing a Wheatstone bridge for performing pressure measurements with a pressure sensor disposed on the distal end of the guide wire, the insulation between the conductors is of great importance to enable detection of small signal deviations. Typically, a sensor with a sensitivity of 5uV/V/mmHg and resistors of 1 kOhm each should require an insulation better than approximately 10 MOhm to detect a pressure increment of 1 mmHG. Therefore, the male contact has to be thoroughly cleaned from contaminants, such as bodily fluids, before it is inserted into the female connector. In the case of a male connector with an essentially smooth connecting surface, i.e. connecting surfaces without recesses, channels, abrupt diameter changes or similar, the cleaning could be made easily enough, for example with a cloth However, under stressed circumstances this could easily be forgotten, thereby leaving a substantial risk for improper connection between the male and the female connectors, as described above Therefore, it is an object of the present invention to provide a device for ensuring that contaminants present on a male connector for introduction into a corresponding female connector is automatically wiped off before the conductive sectιon(s) of the male connector is brought into contact with the corresponding conductive sectιon(s) disposed in an interior channel of the female connector According to the invention, this object is achieved by disposing a flexible wiper means in the interior channel of the female connector For the purpose of this patent application the term "wiper means" relates to a device having the capability to mechanically remove not permanently attached matter from a surface. The wiper means is of a generally toroid shape, and the central hole of the toroid has a diameter smaller than the diameter of the male connector. Examples on wiper means designs according to the present invention shall be described herein, with reference to the attached drawings, wherein: Fig. 1 shows a guide wire with a male connector used within a catheter, and a female connector connected to a monitor. Fig. 2 is an enlarged cross-sectional view of the tip of a typical male connector. Fig. 3 shows a female connector provided with a first embodiment of a wiper device according to the invention for cleaning the male connector of a guide wire. Fig. 4 is an enlarged cross-sectional view of a first embodiment of a wiper device according to the invention in a state before a male connector is inserted. Fig. 5 shows the wiper device according to fig. 4 in a state where the male connector is being inserted. Fig. 6 shows a female connector provided with a second embodiment of a wiper device for cleaning of the male connector of a guide wire. Fig. 7 is an enlarged cross-sectional view of a second embodiment of a wiper device according to the invention in a state before a male connector is inserted. Fig. 8 shows the wiper device according to fig. 7 in a state where the male connector is being inserted. Fig. 9 is an enlarged cross-sectional view of a third embodiment of a wiper device according to the invention in a state before a male connector is inserted. Fig. 10 shows the wiper device according to fig. 9 in a state where the male connector is being inserted. In the figures, like details are designated with same referral numbers. Fig. 1 schematically shows the components of a typical guide wire system including a guide wire 4 with a sensor 6 at its distal end and a male connector 3 on its proximal end. The guide wire is inserted within a balloon catheter 5. The male connector is adapted to be inserted into a female connector 2 which provides electrical connection to a monitor device 1. Fig. 2 is an enlarged cross sectional view of the tip of a typical male connector. Molded into an insulating material 11 , such as epoxy, is a core wire 10 and two conductive members 12 A, 12B, whereby the upper conductive member 12A (when viewed in fig. 2) is connected to the core wire 10 and the lower conductive member 12B (when viewed in fig. 2) is connected to a conductor 13. The length of the guide wire is covered by a guide wire tube 14 that selectively may be electrically insulating or conductive. The diameter of the male connector is typically 0.36 mm (0.014"). A first embodiment of a female connector according to the invention will now be described with reference to fig. 3 through 5. In fig. 3 the male connector 3 of fig. 2 is shown in a position for insertion into a female connector 2. The female connector body is of a generally hollow tubular shape, i.e. an interior elongated channel 30 into which the male connector is inserted extends through the female connector. Conductive members 15 of the female connector, to be contacted by the corresponding conductive members 12A, 12 B and, optionally, the guide wire tube 14, are provided at the inner wall of the channel 30. Circumferentially disposed around the inner wall of the female connector channel 30, and adjacent to the orifice of said channel, is a flexible ring 20. The flexible ring, typically an O-ring, is kept in place by the side walls of a recess 16 that runs circumferentially within the orifice of the channel 30 and substantially perpendicular to the central axis of the channel, as is best seen in fig. 4 and 5. The inner diameter of the flexible ring 20 is selected to be slightly smaller than the diameter of the male connector 3, such that when the male connector is pressed through the central hole of the ring, the ring closes on the outer essentially cylindrical surface of the male connector. The material of the flexible ring is any suitable flexible material, including nitrile rubber, EPDM rubber and silicone rubber. Preferred hardness of the flexible material is 30 - 60 Shore A. Thus, when a male connector 3 is inserted into a female connector 2 with a wiper device of this first embodiment and, thus, is urged through the hole in the flexible ring 20 contaminants will be wiped off from the essentially cylindrical surface of the male connector, thereby preventing them from entering the female connector and consequently preventing the contaminants interference on the electrical measurements. However, the proper function of this first embodiment of wiper device is dependent on a uniform thickness of the male connector, i.e. the diameter of the male connector has to be substantially the same along that length of the male connector that is passed through the flexible ring As this is not always the case a second and presently preferred embodiment of wiper device shall now be described with reference to fig. 6 through 8. Fig. 6 is similar to fig. 3, except that the flexible ring near the orifice of the female connector channel 30' is replaced by a flexible membrane 21 provided with a central opening 22 As is best seen m fig 7 and 8, which figures are enlargements of the area marked with a circle in fig. 6, the flexible membrane 21 is formed as a cap that is fitted on the top end portion of a sleeve 23 inserted in the interior channel 30' of the connector. The sleeve outer diameter is typically 3 mm. As a means for holding the elastic walls of the membrane in place a circumferential groove 26 is formed m the top end portion of the sleeve 23. The diameter of the central opening 22 of the flexible membrane 21 is selected such that it, when it is inserted in the female connector 2, is slightly smaller than the minimum diameter of a corresponding male connector 3 Thus, when the male connector is pressed through the central opening 22, the edge of the opening closes on the outer longitudinal surface of the male connector. The portion of the membrane 21 surrounding the central opening 22 will yield elastically m the direction of insertion of the male connector 3 in proportion to the thickness of the male connector, but the edge of the central opening will remain m circumferential contact with the male connector. Consequently, when the male connector 3 passes through the opening 22 in the membrane 21 , the edge of the opening will wipe off contaminants from the outer longitudinal surface of the male connector, thereby preventing them from entering the female connector and consequently preventing the contaminants interference on the electrical measurements. The material of the flexible membrane 21 can be selected from any suitable flexible material, including latex rubber and silicone rubber. Typically, the membrane is made with a thickness within the range of 0.05 through 0.3 mm, preferably approximately 0.1 mm. This second embodiment of wiper device according to the invention has the advantage, as compared to the first embodiment, that the flexibility of the membrane allows it to wipe away contaminants from the outer longitudinal surface of male connector even in a case where the diameter of the male connector is not uniform, e.g. is tapered towards its end. It also imparts less friction on the male connector at the moment the tip of the connector penetrates the central opening, thereby reducing the risk of breaking the male connector. Furthermore, the membrane 21 is easy to produce. For example, the membrane could initially be made in the shape of a thin disk with a central hole. It is then deformed to the shape of a cap with a central opening 22, as shown in fig. 6 through 8, when it is forced into the female connector by the insertion of the sleeve 23. A preferred method for forming the membrane type wiper device is by dipping a core element of a complementary shape into fluid latex rubber which is then vulcanized with heat, after which the core element is removed. The central opening may be provided by a pin on the core element or by punching the membrane after is has been cured. A third embodiment of a wiper device according to the invention is shown in fig. 9 and 10, which figures are enlargements of an area corresponding to the area marked with a circle in fig. 6. In this third embodiment, an end stop 28 having a central hole of a diameter large enough to let the male connector through is disposed in the interior channel 30" of the female connector body 29. It should be noted that although the end stop is shown as formed integral with the female connector body, it could also be formed as a separate detail attached to the inner wall of the connector. A sleeve 23', similar to the sleeve of the second embodiment above and as shown in fig 6, is inserted in the channel 30". Between the sleeve 23' and the end stop 28 is clamped a flexible absorbing member 24 shaped as a generally hollow cylinder. The absorbing property of the flexible absorbing member 24 is due to the sponge-like structure of the material from which it is formed. Examples of such material are OASIS Fibre Superabsorbent (cross-linked acrylate copylomer) available from Technical Absorbent Ltd, and Drikette® Desiccant Paper available from Multisorb. The toroid inner diameter of the flexible absorbing member 20 is selected to be slightly smaller than the diameter of the male connector 3. The flexible absorbing member 24 has the same function as the flexible ring 20 described with the first embodiment above, but in addition it absorbs contaminants in a liquid form, e.g. blood plasma, into the member. Furthermore, due to the sponge-like properties of the material the wiper device of this third embodiment is useful also for male connectors having a non-cylindrical shape. The wiper device of this third embodiment also exhibits the advantage that very thin liquid films, that otherwise could remain on the male connector, are prevented from entering the female connector due to the absorbing action of the sponge-like material.

Claims: CLAIMS 1. A female electrical connector (2) for cooperative engagement with a male connector (3) of a guide wire (4), comprising a flexible wiper device (20, 21, 24) disposed in a male connector receiving channel (30, 30', 30") extending into the female connector, for preventing loosely adhered contaminants on the male connector to enter into said female connector during insertion of the male connector in said female connector. 2. The female connector (2) according to claim 1 , wherein said wiper device (20, 21 , 24) is of a generally toroid shape with its central opening adapted to receive the male connector (3), and wherein the inner diameter of said central opening is smaller than the diameter of the male connector (3). 3. The female connector (2) according to claim 2, having at least one conductive member (15) disposed within the male connector receiving channel (30), a recess (16) formed circumferentially around the wall of the channel (30) substantially perpendicularly to the axis of the channel, and a flexible ring (20) with an essentially circular cross-section constituting said wiper device disposed within said recess (16). 4. The female connector according to claim 2, wherein said wiper device (21) is shaped as a flexible membrane, said membrane having a central hole (22) for receiving the male connector and said central hole having a diameter smaller than the smallest diameter of the male connector to be passed therethrough. 5. The female connector (2) according to claim 2, having at least one conductive member (15) disposed within the male connector receiving channel (30'), a substantially cylindrical sleeve (23) inserted into the central hole and said wiper device shaped as a flexible membrane (21) attached to the top of said sleeve (23), said membrane (21) having a central hole (22) for receiving the male connector and said central hole (22) having a diameter smaller than the smallest diameter of the male connector to be passed therethrough, and a portion of said membrane adjacent to its central hole being oriented substantially perpendicularly to the axis of the channel (30'). 6. The female connector (2) according to any of the previous claims, wherein said wiper device (20, 21) is formed from a material selected from the group consisting of nitrile rubber, EPDM rubber and silicone rubber. 7. The female connector according to claim 2, wherein said wiper device (24) is formed as a generally cylindrical, hollow member, said wiper device being formed of a liquid absorbing material. 8. The female connector (2) according to claim 7, wherein said wiper device (24) is disposed between an end stop (28) attached in the channel (30") and a substantially cylindrical sleeve (23') inserted into the channel (30"). 9. A system for electrical measurement in the femoral artery, including a guide wire (4) for introduction into the femoral artery, the guide wire having a sensor (6) on its distal end, and a male connector (3) on the proximal guide wire end; a signal monitor (l)for receiving signals from the sensor; a female electrical connector (2) according to any of the previous claims, for receiving said male connector of the guide wire, and coupled to said signal monitor.

Inventors: AAKERFELDT DAN, JENSEN PETER, AAKERFELDT, DAN, JENSEN, PETER
Applicants: AAKERFELDT DAN, JENSEN PETER, RADI MEDICAL SYSTEMS, AAKERFELDT, DAN, JENSEN, PETER, RADI MEDICAL SYSTEMS AB
Application year: 1998
Main classification: H01R13
IPC codes: A61B5, A61B8, A61B18, A61M25, H01R13, H01R24