NL2018666B1 - Outer coaxial isolator device - Google Patents

Abstract

An insulator device (16: 48: 70) for the outer coaxial shielding is provided, the insulator device (16: 48: 70) comprising ring capacitors (22) and ferrite blocks (20) in the form of apertured disks, and an elongated electrically conductive hollow tube (30) extending through and in electrical contact with the ring capacitors (22) and ferrite blocks (20), a plurality of electrically conductive lips (32, 50) being provided to make contact with at least a portion of each ring capacitor (22). The lips (32, 50) can be formed from the hollow tube (30) and / or from a housing (18).

Description

Outer coaxial isolator device

FIELD OF THE INVENTION

This invention relates to an outer coaxial insulator device, in particular a device that is used within double galvanic insulator assemblies to provide voltage protection to outer coaxial shielding.

BACKGROUND OF THE INVENTION

A shielded coaxial cable is used to provide power for devices within a cable television network. Dual galvanic isolator circuits are used to improve shielding characteristics of the coaxial cable, either by protecting the outer coaxial shield or by protecting the inner conductor of the coaxial cable. The double galvanic isolator circuits are located in or form part of a radio-frequency (“RF”) shielded housing. Problems arise at electrical interfaces between different components within the double galvanic isolator circuits.

Summary of the invention

According to the present invention, an insulator device for the outer coaxial shield is provided, the insulator device comprising at least one capacitive element and at least one inductive element, each element having the shape of an apertured disc, and an elongated electrically conductive element, or tube extending through and in electrical contact with the apertured disks, wherein at least one electrically conductive lip is provided to contact at least one portion of the capacitive element, thereby providing an additional area of electrical contact with the capacitive element, except for the elongate conductive element only. The electrically conductive lip is thus in physical contact with the capacitive element, and by being electrically conductive, the electrical contact between the capacitive element and components in electrical connection with the lip is improved.

As a rule, the apertured disks forming the capacitive element and the inductive element have a first surface, a second surface, and a central channel extending between the first and second surfaces, the elongated conductive element being in the channel of each apertured disk.

The at least one lip can extend substantially 90 with respect to the elongate conductive element in order to have contact with an outer surface of the capacitive element.

The elongated conductive element can be in the form of a hollow tube and more preferably a hollow flexible tube that can be molded to produce at least one lip which extends over at least one part of the capacitive element, and preferably extends over at least one extends two thirds of a contact surface of the capacitive element.

Where the tube is deformable, a plurality of radial slots are preferably provided in at least one position along the elongate conductive element, the slots extending through the wall, so that the wall is provided with openings in the region of the slot.

Preferably, each slot extends in the direction of elongation of the elongate conductive element. Because slots extend in part along the length of the tube, the tube can be formed so that lips are produced which extend over at least a part of the capacitive element, in particular over a plane of the capacitive element.

A set of slots formed from a plurality of radial slots may be repeated at fixed distances along the tube, the distance between each set of slots corresponding to the distance between which lips are required. For example, a first set of radial slots will provide a first set of lips for maintaining contact with a surface of a first capacitive element with the following set of slots providing a second set of lips for maintaining contact with a second capacitive element that is on fixed distance along the tube, and repeated sets of slots are provided that depend on the number of capacitive elements provided on the conductive element.

Preferably, the slots are equally spaced in circumferential direction, and 2, 3, 4, 5 or even more slots may be provided, with a particular preference for four slots.

The capacitive elements may preferably be ring capacitors, the inductive elements preferably being formed from ferrite material and as a rule each being in the form of an apertured ferrite block.

The insulator device may also comprise a housing, generally metal or other electrically conductive material, in which the at least one capacitive element, the at least one inductive element and the elongated conductive element are located, lips being formed from parts of the housing.

The housing may be formed with predetermined lip regions, the predetermined lip regions being easily deflectable away from the rest of the housing to engage the capacitive elements.

Where lips are formed from the housing, the lips may be in contact with both a capacitive element and an insulating element, this acting to hold the insulating element in place.

In a particularly preferred embodiment, both the conductive element and the housing can both be provided with lips, such that the lips that belong to the tube are in contact with one side of each capacitive element and lips that belong to the housing with the other side of each capacitive element.

The invention is described below, by way of example, and with reference to the accompanying drawings, in which:

Top form

Figure 1 shows a schematic electrical diagram of an outer coaxial insulator device;

Figure 2 shows a cut-out view of a first embodiment of the invention that accommodates an elongated conductive element;

Figures 3 (a) and (b) show the conductive elongate element in side view and end view, respectively;

Figures 4-6 show perspective views illustrating assembly of the first embodiment;

Figure 7 shows a cut-away view of the components in the first embodiment; Figure 8 shows a cut-out view of a second embodiment and progress of the invention;

Figures 9-11 show the assembly of the second embodiment;

Figure 12 shows a cut-away view of the components in the second embodiment;

Figure 13 shows a cut-out view of a third embodiment of the invention; and

Figure 14 shows a cut-away view of the components in the third embodiment.

Description

Fig. 1 shows an electrical diagram of an outer coaxial filter element of a double galvanic isolator device or module 10 comprising a plurality of ferrite blocks 12 which are electrically connected in series and capacitors 14 connected in parallel and connected thereto. The number, size and values of the components 12, 14 vary depending on the desired performance. Problems arise with electrical interfaces between the components that influence efficiency and reliability.

To reduce electrical interfaces and thereby promote reliability and efficiency, modified double galvanic isolator devices are proposed as shown with reference to Figures 2-14.

A first embodiment is shown in relation to Figures 2-7. The double galvanic isolator module 16 is shown in vertical cross section such that the half module is shown and comprises an electrically conductive module body 18 within which ferrite blocks 20 are located and ring capacitors 22 in the form of apertured disks with circular outer sides of a central channel provided between the two faces. Ferrite insulators 24 with a central aperture or channel are disposed between adjacent blocks and ferrite ring capacitors to prevent electrical contact between ferrite blocks and ring capacitors. An electrically conductive disk ring 26 is disposed between each ring capacitor 22 and phenolic insulator 24 and is adapted to be physically and electrically in contact with conductive housing 18 to ensure an electrical connection between housing 18 and ring capacitor 22.

Hollow flexible elongated tube 30 is electrically conductive and extends through apertured elements 20, 22, 24, 26 and includes groups of lips 32 at longitudinally spaced positions corresponding to the location of ring capacitors 22 such that lips 32 are in direct and electrical contact with an adjacent ring capacitor 22. The electrically conductive lips 32 provide areas for electrical contact between the tube 30 and each capacitor, so as to reduce electrical boundaries between the inner tube 30 and the ring capacitor interfaces. Although the housing with two ferrite blocks 20 and two ring capacitors 22 is shown, pairs of a single ferrite block and a single capacitor can be repeated if necessary to achieve the desired properties of the module and the length of the module housing can increase according to requirements.

Tube 30 is shown in more detail with reference to Figures 3 (a) and 3 (b) and has three sets 34, 34 ', 34 "of radial slots 36 of equal length which are placed at equal distances along the length of tube 30, with four radial slots 36 in each set placed at equal distances around the tube circumference.Each slot is cut out or formed to extend through the wall.The number of slots in each set and the distance between the sets depends on the number and the spread of the ring capacitors 26, a set of slots being provided for each ring capacitor 22. Although Figure 3 shows three sets of four radial slots along tube 30. the number of slots per set can be two, three, four or more. deformable tube 30 can deform the slotted areas during assembly of the module to form tabs 32 as shown in Figure 2. This is seen with reference to Figures 4-7 where the construction of module 16 is shown.

To mount module 16, subassembly of retaining ring 40, end outer insulator 42, electrically conductive disc ring 26, ring capacitor 22 and pre-cut inner tube 30 is formed. Tube 30 is introduced into the channel or opening of capacitor 22 such that it touches retaining ring 40. Tube 30 is then forced inwards in the direction of capacitor 22, see Figure 5, whereby the tube walls extend outwardly near slots 34 to create hinged lips 32 with a double wall thickness, lips 32 having direct physical and electrical contact with the ring capacitor 22. Thus, the boundaries between the inner tube and the ring capacitor interfaces are pushed back by the folded lips contacting one face of each ring capacitor 22. The length of each slot is approximately twice the radial distance between the outer diameter of the tube 30 and the outer edge of ferrite block 20, with a clearance for the radius of curvature at the end of the lip to cause each lip 32 to extend about two-thirds of cover the exposed contact surface of capacitor 26.

Ferrite block 20 is added to this sub-assembly such that the tube 30 extends through the central opening or channel of ferrite block 20. Subsequently, ferrite insulator 24, electrically conductive disc ring 26 and ring capacitor 22 are then added to the assembly as shown and the lip forming process is repeated for the gaps associated with the set 34 ', see Figure 6.

This arrangement of parts and lip formation is required for as many capacitors as module 16, repeated, and finally end insulator 44 is applied, followed by electrically conductive module body or housing 18. Figure 7 shows all components in module 16 in a cut-away view. While tube 30 with protruding lips 32 is shown, the lips are only made after each ring capacitor 22 has been placed on tube 30. After all components are placed on tube 30, the components are compressed so that all fingers of electrically conductive rings 26 grip firmly on module body 18 and the overall assembly is held compressed by the fit between the module body 18 and the retaining ring 40, thereby becoming the finished module produced as shown in Figure 2.

A second embodiment 48 is shown in Figure 8 where lips 50 are formed in module housing 18 to physically and electrically connect ring capacitors 22 to the electrically conductive housing 18. Electrically conductive tube 52, which is formed without slots, extends through the central openings of the disc components. By piercing and folding lips of body 18 during assembly, module body 18 is brought into direct contact with one surface of the ring capacitor 22, so that electrical boundaries between module body 18 and the ring capacitor interfaces are pushed back.

Figures 9-12 illustrate the assembly of the second embodiment. First, end insulator 42 and electrically conductive inner tube 52 are inserted into empty module body 18, see Figure 9. Multiple circumferentially spaced lips 50 are then created by piercing or punching them into the side of module body 18 and bent down around end insulator 42 to secure in place against end wing 54, see Figure 10, and thus provide an electrical and physical contact point for the next component, ring capacitor 22. Ring capacitor 22 is then passed through the tube 52 and placed on end insulator 42, one of openings provided electrically conductive inner cup ring 60 is supplied to the tube 52 until both inner cup ring 60 and lips 50 of module body 18 are in good electrical contact with ring capacitor 22. Ferrite block 20 and ferrite insulator 24 are both passed through tube 52 in turn, and another set of lips 50 'is drilled into module body 18 and bent inward to secure the components in place, see Figure 11. Making contact lips 50 in module body 18 reduces the electrical boundaries between module body 18 and the ring capacitor interfaces.

Figure 12 shows components of the assembly of module 48, each group of components being repeated between successive sets of longitudinally placed lips as often as needed to obtain the desired electrical properties for module 48. Thus, although shown with two ferrite blocks 20, 20 ', any number of ferrite blocks and associated components can be included in module 18.

To complete the assembly of module 48 for the components shown in Figure 12, another set of tabs in module body 18 is pierced and bent downward over first ferrite insulator 24. The process of adding capacitor 22 ", inner cup ring 60", ferrite block 20 "and ferrite insulator 24", followed by piercing and bending the lips 50 in module body 18, is repeated until the desired number of capacitors 22 is mounted. The last insulator 24 "is attached with the last set of lips and finally end capacitor 22", end ring 60 "and end insulator 44 are added and holding ring 62 is pressed into module body 18 to complete assembly.

The third embodiment 70, shown in Figures 13 and 14, combines the use of external lips which are thinned inwards from housing 18, such as in embodiment two, wherein lips are formed from the slotted flexible electrically conductive tube of the first embodiment to provide a minimal electrical limit configuration. Inner cup rings 60, 60 ", 60" are not required in this embodiment since tube 30 provides lips 32 for making physical and electrical contact with one face of the ring capacitors 22 and lips 50 with the other face of ring capacitors 22.

The present invention reduces electrical interfaces in an outer coaxial insulator device by reducing the number of internal components, for example by replacing rings with lips integrally formed as part of the required components. This provides modules that contain the required elements required for an outer coaxial filter in a sub-assembly that, compared to the prior art, reduces the electrical interfaces between components for improved unit efficiency and reliability.

Claims (13)

An insulator device for the outer coaxial shield, the insulator device comprising at least one capacitive element and at least one inductive element, each element being in the form of an apertured plate and an elongated electrically conductive element in the form of a flexible hollow tube extending through and in electrical contact with the apertured disks, wherein at least one electrically conductive lip is provided to contact at least one portion of the capacitive element, the tube being deformable about at least one produce a lip extending over at least a portion of the capacitive element. Insulator device according to claim 1, wherein the at least one lip extends substantially 90 ° with respect to the elongate conductive element. An insulator device as claimed in claim 1 or claim 2, wherein the apertured disks forming the capacitive element and the inductive element have a first surface, a second surface and a central channel extending between the first and second surfaces, the elongated conductive element is disposed within the channel of each apertured disc. An insulator device according to any one of the preceding claims, wherein the elongate conductive element is a hollow tube. An insulator device according to any one of the preceding claims, wherein a plurality of radial slots are arranged in at least one position along the elongate conductive element. An insulator device according to claim 5, wherein each slot extends in the direction of elongation of the elongate conductive element. An insulator device as claimed in claim 5 or claim 6, wherein the slots are uniformly spaced in circumferential direction. An insulator device as claimed in any one of claims 5-7, wherein a set formed from a plurality of radial slots is repeated along the tube at spaced intervals. An isolator device according to any one of the preceding claims, further comprising a housing in which there are at least one capacitive element, at least one inductive element and the elongated conductive element, lips being formed from parts of the housing. An isolator device according to claim 9, wherein the lips make contact with both a capacitive element and an insulating element, thus holding the insulating element in place. An isolator device according to claim 9 or claim 10, wherein the housing is formed with predefined lip regions. An isolator device according to any one of the preceding claims, wherein the capacitive elements are ring capacitors. An isolator device according to any one of the preceding claims, wherein the inductive elements are formed from ferrite material.