Cable assembly, connector apparatus and method

Abstract

A connector apparatus for connecting to a cable assembly that comprises coaxial cable and at least one wire and/or fluid conduit and/or further layer, wherein the connector apparatus comprises a housing that houses a connector and at least one further connector, wherein the connector is configured to electrically connect to the coaxial cable when the connector apparatus and the cable assembly are in an engaged state, the at least one further connector is configured to connect to the at least one wire and/or fluid conduit and/or further layer when the connector apparatus and the cable assembly are in the engaged state, the connector is configured to allow free rotation relative to the connector of the coaxial cable around an axis when the coaxial cable is electrically connected to the connector in the engaged state.

Claims

1. A connector apparatus for connecting to a cable assembly that comprises coaxial cable and at least one of wire, fluid conduit, or further layer, wherein the connector apparatus comprises: a housing for housing a connector and a further connector, wherein the connector is configured to electrically connect to the coaxial cable when the connector apparatus and the cable assembly are in an engaged state; the further connector is configured to connect to at least one of the wire, the fluid conduit, or the further layer when the connector apparatus and the cable assembly are in the engaged state; the connector apparatus is configured to allow free rotation of the coaxial cable around an axis when the coaxial cable is electrically connected to the connector in the engaged state.

2. The connector apparatus according to claim 1, wherein the further connector is for connecting to at least one of wire or fluid conduit, and is located at an off-axis position away from said axis.

3. The connector apparatus according to claim 1, wherein the further connector is for connecting to the further layer of the cable assembly.

4. The connector apparatus according to claim 1, further comprising a tension member connector for connecting to a tension member of the cable assembly when in the engaged state.

5. The connector apparatus according to claim 1, wherein the connector comprises means for applying compression force to a component of the coaxial cable in a direction substantially along said axis when in the engaged state.

6. The connector apparatus according to claim 5, wherein the means for applying compression force comprises a spring.

7. The connector apparatus according to claim 1, comprising a bushing and optionally the means for applying compression force is arranged to apply compression force to the bushing.

8. The connector apparatus according to claim 7, wherein the coaxial cable comprises an end connector and the means for applying compression force is arranged to apply force between a face of the bushing and a face of the end connector.

9. The connector apparatus according to claim 7, wherein the connector apparatus comprises at least one of: a channel for guiding the bushing into a retained position; a locking face for engaging with a face of the bushing thereby retaining the bushing in position; or a step feature for constraining the bushing against pulling forces when the bushing is in a retained position.

10. The connector apparatus according to claim 9, wherein the connector apparatus comprises a locking feature on a flexible tab that is configured to travel along the channel and ramp over and lock behind the locking face.

11. The connector apparatus according to claim 7, wherein the bushing comprises a tooth and socket arrangement.

12. The connector apparatus according to claim 1, wherein the cable assembly comprises a further conducting shield around the coaxial cable, and the further connector is for connecting to the further conducting shield.

13. The connector apparatus according to claim 12, wherein the connector comprises a first electrical connection configured to electrically connect to a conducting shield of the coaxial cable when in the engaged state, and the further connector comprises a second electrical connection for electrically connecting to the further conducting shield when in the engaged state, and the first electrical connection is electrically isolated from the second electrical connection thereby to enable the conducting shield and the further conducting shield to be held at different electrical potentials.

14. The connector apparatus according to claim 1, configured to connect to an electromagnetic source for applying microwave energy for medical applications, wherein the connector is configured to provide for application of microwave energy from the electromagnetic source to the coaxial cable during said rotation.

15. The connector apparatus according to claim 1, wherein the connector apparatus is configured to connect to a cable assembly comprising: a coaxial cable comprising an inner conductor, a conducting shield around the inner conductor, and an insulating layer separating the inner conductor and the conducting shield; and a further conducting shield around the coaxial cable, wherein the further conducting shield is configured to be connected, in operation, to an electrical potential different to the electrical potential of the conducting shield of the coaxial cable.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Embodiments of the invention are now described, by way of non-limiting example, and are illustrated in the following figures, in which:

(2) FIG. 1 is an electrical schematic illustration of a microwave energy delivery system according to some embodiments of the invention;

(3) FIG. 2(a) is an axial cross-sectional illustration of a cable assembly according to some embodiments of the invention;

(4) FIG. 2(b) is a longitudinal cross-sectional illustration of a microwave energy delivery system interconnect cable assembly according to some embodiments of the invention;

(5) FIG. 3 is a longitudinal cross-sectional illustration of a microwave energy delivery system interconnect cable assembly according to some embodiments of the invention;

(6) FIG. 4(a) is an illustration (end view) of a cable retention mechanism according to some embodiments of the invention;

(7) FIG. 4(b) is an illustration of a cable retention mechanism according to some embodiments of the invention.

(8) FIG. 5 is an isometric view of an alternative cable retention mechanism according to some embodiments of the invention;

(9) FIG. 6 is an isometric view of an alternative cable retention mechanism according to some embodiments of the invention detailing a bushing design;

(10) FIG. 7 is an isometric view of an alternative cable retention mechanism according to some embodiments of the invention detailing alignment features;

(11) FIG. 8 is an isometric view of an alternative cable retention mechanism according to some embodiments of the invention detailing locating features;

(12) FIG. 9 is an isometric view of an alternative cable retention mechanism according to some embodiments of the invention detailing locking and alignment features; and

(13) FIG. 10 is a longitudinal cross-sectional illustration of an alternative cable retention mechanism according to some embodiments of the invention detailing locking feature clearance.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(14) Reference will now be made in detail to compositions or embodiments and methods of the invention, which constitute the best modes of practicing the invention presently known to the inventors. However, it will be understood by those skilled in the art that the claimed subject matter may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as to not obscure the claimed subject matter.

(15) 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 embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments in accordance with the present invention is defined by the appended claims and their equivalents.

(16) A system for delivering microwave energy is illustrated in FIG. 1. In this system there is a mains supply 1, 2 isolated from the supply circuitry by a medical grade isolation transformer 3 which may be a transformer, power supply unit and/or may also include a dc/dc converter, to provide a voltage supply 4 and a system ground or 0V reference 5 to power a microwave generator system 6 enclosed within an earthed enclosure 7. In medical applications requiring floating connectors the chassis earth and system ground or 0V reference may be at different potentials due to the requirement to isolate the patient from earth to prevent the risk of electrical shock.

(17) The microwave generator system 6 includes an isolated output connected via a high voltage microwave capacitor 8 to supply the fundamental frequency. The microwave generator system is electrically isolated floated from the chassis ground and is powered by a type BF medical grade power supply (Craftec GNT400) to provide the required patient isolation negating the requirement for a coaxial microwave DC block. Connection to a microwave cable 9 is made via a standard slide-on microwave coaxial connector such as an SMP, BMA or SMA connector supplied by Amphenol or M/A-Com which connects the coaxial inner via connection 10-11 and the coaxial conducting shield (outer conductor) via connection 12-13 to the system ground or 0V. Data connections are made via 101-102 and may include a plurality of data lines.

(18) The microwave coaxial cable 9 and the data lines 102 form part of a cable assembly and are shielded by a further conducting shield in the form of conductive mechanism 16 which may, for example, be a conductive spring or braided covering. Advantageously this shield is connected to the chassis earth via a connection 14-15 to enhance the EMI performance of the cable assembly. The microwave cable can exit this shield, however it is insulated and spaced accordingly to prevent it electrically contacting the shield. To prevent the patient contacting the chassis earth an insulation barrier 17 provides electrical isolation around the entire cable assembly.

(19) The cable assembly is configured such that in operation, the conducting shield of the coaxial cable is maintained at a first electrical potential (in the embodiment of FIG. 1, the system ground) and the further conducting shield is maintained at a second, different electrical potential (in the embodiment of FIG. 1, the chassis earth).

(20) Referring to FIG. 2(a) a cable assembly is illustrated. In this diagram the insulating sheath 18 surrounds an armour layer in the form of an armour spring 19 which contains a shield such as a braided conductive sheath 20. The armour layer may, for example, comprise any suitable coiled spring, brading or tubing in alternative embodiments. The coaxial microwave cable 26 is located inside the centre of the shield and comprises a centre conductor 21 surrounded by a shielded dielectric 22a, which is in turn surrounded by an electrically conducting shield 22b encased in an insulated jacket 23. A number of insulated conductor wires 24 can also be contained within the assembly, likewise tubing 25 for gas or fluid or any other suitable type of fluid conduit may be contained within the assembly.

(21) Referring to the embodiment of FIG. 2(b) the microwave cable 26 is held within a connector apparatus in the form of a locating fixture 27 at each end of the cable assembly. This locating fixture 27 can also hold pins or sockets 28 to allow for electrical connections 24. The internal shield 20 is connected to ground 30 via this type of connection. The armour spring 19 is arranged to be spaced with an enhanced pitch 32 to provide increased strength. The insulating jacket 18 encloses the assembly to prevent patient contact to earth. A tension member 35 is attached to the locating fixture 27 to prevent stretching forces 36 acting on the microwave cable connectors 38. Advantageously the locating fixture 27 is designed to permit the free rotation of the microwave cable 26 within the cable assembly. This feature permits the torque to be removed from the cable assembly by allowing the outer cable assembly to twist and rotate without restriction from the inner microwave cable 26.

(22) The tension member 35 in the embodiment of FIG. 2 is a rope formed of Kevlar but any suitable material may be used. The tension member may have an elastic limit or breaking greater strain greater than other components of the cable 26. When the cable is held within the locating fixture, the tension member 35 may be arranged to be shorter than the coaxial cable and/or other cables 24 or conduits 25, to ensure that tension member rather than the coaxial cable 26 and/or other cables 24 bears the majority, or all, of any tensile load experienced by the cable.

(23) In the embodiment of FIG. 2, the armour spring is a 0.7 mm diameter stainless steel wire spring with pitch 1.5 mm and outside diameter of 5 mm. Any other suitable material may be used for the armour, for example carbon fibre or any suitable metal or composite material. The insulating jacket 23 of FIG. 2 is a platinum cured silicone jacket, but any other suitable material can be used in alternative embodiments, for example vinyl, nitrile or any other suitable flexible plastic or rubber material. The jacket may, in some embodiments, be coated on its internal surface with silver paint or lined with silver foil, or covered or coated with other thermally reflective material.

(24) An air gap may be provided inside the armour layer in some embodiments, to reduce thermal contact between the coaxial cable and outer layers of the cable assembly.

(25) Referring to FIG. 3 the embodiment describes detail of a connector apparatus in the form of the locating fixture 27. In this illustration a housing in the form of a main body 41 of insulating material contains locations to accommodate coaxial microwave cabling 45 including in a cable assembly, such that the coaxial microwave cabling is electrically connected to a connector when it is accommodated in the body and engaged. The housing also contains at least one further connector in the form of electric connecting pins or sockets 46. The electric connecting pins or sockets 46 are configured to connect to one or more wires, such as wires 24 or further cables that may be included in the cable assembly. In alternative embodiments the pins or sockets 46 may be supplemented or replaced by a connector configured to connect to a fluid conduit that may be included in a cable assembly.

(26) A bushing fixture 42 prevents the microwave connector 51 from being withdrawn. The microwave cable 45 enters the bushing 42 and is restrained within it. The bushing 42 connects to the main body 41 via a thread 44, optionally this may be a friction fit or other fitment such as locking ramps. A compression spring 43 pushes the microwave connector outward towards a tapered mating face 49 which ensures alignment concentricity. The main body 41 also features a ramped insertion port 50 to ensure that connections align properly prior to mating. The compression spring 43 mates with a parallel face 47 on the bushing to prevent the spring lodging between the bushing and the microwave connector. The compression spring 43 mates with another parallel face 48 on the microwave connector 51 to deliver the retention force and to permit the microwave connector to turn freely inside the assembly.

(27) Referring to FIG. 4 (a) the microwave cable 54 is inserted through a c-cut into the bushing 52 and retained by a collar feature 53 which maintains the axial alignment of the cable 54. The fit is such that the cable is permitted to rotate. In an alternative view illustrated in FIG. 4 (b) the microwave cable is held in alignment by the internal face 55. Advantageously the C shaped cut region 56 permits the bushing to be added to the cable after the cable has been manufactured. The moulded thread 57 also possesses the C shaped cut and the material (Visijet SLA acrylic as an example) can flex to accommodate the cable. The bushing may also be fabricated without a cut-out and may be incorporated with the cable prior to addition of the connectors. Alternatively the cut away portion may be also be added to the bushing to provide additional strength in the housing.

(28) In alternative embodiments the locating fixture 27 includes a tension member connector for connecting to a tension member of the cabling, for example tension member 35, when in an engaged state.

(29) Referring to FIG. 5 a bushing arrangement according to an alternative embodiment is illustrated. This embodiment permits the retention of a connector without the requirement for the connector to pass through small orifices during assembly.

(30) In this embodiment the bushing 58 retains a sprung connector such as a BMA connector 59 with spring loading 60 inside a standard Alden PL1200 connector core housing 61. Referring to FIG. 6, the bushing 58 has an internal cylindrical rib 62 which captures the spring 60.

(31) Referring to FIG. 7, the bushing 58 slides into position along channels 64 and is retained against a ramp and locking face 63 and constrained against pulling forces by a front step feature 64.

(32) Advantageously the bushing 58 features a tooth 65 and socket 66 arrangement as illustrated in FIG. 8 permitting the manufacture of identical mating parts.

(33) Referring to FIG. 9 the bushing 58 features ramped locking features 67 mounted on a flexing tab 68 which travels along the channels 64 and ramps over and locks behind the ramped locking face 63.

(34) Additional rib features 69 are included to guide the parts along the channels 64 and prevent misalignment and mechanical support. The assembly involves passing the BMA connector 59 through a PL1200 core 61 and placing a pair of bushings 58 over the BMA connector 59, capturing the spring 60 and then returning this assembly back into the core to be locked into position.

(35) Referring to FIG. 10 the flexing tab 68 is designed to have sufficient clearance between the inner face 70 and the BMA connector outer face 71. This clearance is designed to be more than the height of the locking ramp 67 to permit the assembly to pass over all the ramped locking faces 63 located along the channels 64 in the PL1200 core.

(36) It will be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.

(37) Each feature disclosed in the description, and (where appropriate) the claims and drawings may be provided independently or in any appropriate combination.