GB2156170A

GB2156170A - Electrical connector

Info

Publication number: GB2156170A
Application number: GB08404273A
Authority: GB
Inventors: Keith Henry Jones; David Ralph Pinney
Original assignee: CANNON ELECTRIC
Current assignee: CANNON ELECTRIC
Priority date: 1984-02-17
Filing date: 1984-02-17
Publication date: 1985-10-02
Also published as: DE3504823A1; GB2156170B; GB8404273D0

Abstract

An electrical connector for making a connection to a screened co-axial electrical cable comprises a two-part enclosure (10, 11) provided with a pair of mutually insulated terminal probes (18, 22). When parts (10, 11) are closed onto a cable (23, 24, 25, 26) and mutually secured, probe (18) penetrates the cable insulation (23) to make contact one with the cable screen. Probe (22) is then displaceable in the enclosure by a rack and pinion (19, 20) to make contact with the inner conductor (26). <IMAGE>

Description

SPECIFICATION Electrical connector This invention relates to an electrical connector by means of which an electrical junction may be made to a screened coaxial cable without requiring parting drilling, or otherforms of preparation ofthe cable.

According to the invention there is provided an electrical connectorfor making a connection to a screened coaxial electrical cable, in which the connector comprises a two-part enclosure provided with a pair of mutually insulated terminal probes adapted, when the parts are closed on to a cable and mutually secured, to penetrate the cable insulation and make contact one with the screen and one with the inner conductor of the cable, the probe which makes contact with the inner conductor being displaceable in the enclosuretomakecontactwiththeinnerconductor afterthetwo parts have been mutually secured.

The probe which makes contactwith the inner conductor is preferably constructed as a forked probe having partially insulated legs which pierce the outer jacket screen, and dielectric and contact the centre conductor between the opposing faces ofthe inside of each leg, thereby making a secure electrical connection, unaffected by long term movement of the centre conductor, and preventing any short circuit between the centre conductor and the coaxial screen.

The probe which makes contact with the inner conductor may be displaceable by a tool, by hand or by a suitable mechanism (such as a rack and pinion).

Preferably a means is provided for preventing the movement ofthe centre probe until the two parts of the enclosure are mutually secured.

A stop may be provided for limiting the displacement ofthe probe beyond a position of engagement with the inner conductor. A latch may be provided for retaining the probe in its fully displaced position thereby to retain the probe in engagement with the inner conductor. Avisual indicator of displacement of the probe to the position of engagement with the inner conductor may be provided.

The probe for engagement with the screen of the cable may be arranged to penetrate the insulation and contact the screen as a result of closure ofthe enclosure parts onto the cable.

In a particularly advantageous form ofthe invention there is provided an additional screen probesimilarto and spaced from the first screen probe, the probe for engaging the inner conductor ofthe cable being disposed therebetween.

The probes may be coupledtoterminalsfor connection to an external circuit, which terminals extend in use radially of the cable, and an RFscreen may be provided in the enclosure which in use extends longitudinally of the cable.

In orderthatthe invention and its various other preferred features may be understood more easily, an embodiment thereof will now be described, by way of example only, with reference to the drawings, in which: Figure lisa pictorial view of a connector constructed in accordance with the invention mounted on a coaxial cable, Figure 2 is a schematic illustration to show the connectionofcontactprobestotheinnerconductor and screen ofthe coaxial cable, Figure3 is a sketch showing partoftheconnectorof Figure 1 to illustrate the operation of a rack and pinion for effecting connection to the inner conductor, Figure 4 is a schematic cross-sectional view taken longitudinallythroughthe rack, and Figure 5 is a partial cross-sectional view taken on the line Y-Y of Figure 4.

A connector housing shown in Figure 1 comprises an enclosure formed oftwo parts 10 and 11 which are secured together about a coaxial cable 12 by means of screws 13. The housing has a recess 14 inside which there is an innerterminal 15 disposed between two outerterminals 16. The outerterminals are coupled with the screen of the coaxial cable whilst the inner terminal is coupled with the inner conductor of the coaxial cable in a manner as will be hereinafter described. An aperture 17 is provided to permit access for operation of a pinion of a rack and pinion device for making connection to the inner cable. Each ofthe enclosure parts 10 and 11 have longitudinally extend- ing troughs of semi-circularform which align to form a channel of circular cross-section in which the coaxial cable is clamped.

Referring now to Figure 2, there is shown a schematic illustration of how engagement is effected to the screen and to the inner conductor ofthe coaxial cable. The enclosure part 11 in its cable receiving recess is provided with two, four pronged screen probes 18 which are coupled to the connection terminals 16. The probes 18 extend into the recess by a depth sufficient to penetrate the insulation of the coaxial cable and to engage the screen of the cable when it is clamped between the two enclosure parts 10,11 in the troughs. By placing the two halves of the connector around the unprepared cable, the action of clamping together the two parts clinches the screen probes and makes the required contact to the screen ofthe cable.

The enclosure portion 11 is provided with a rack 19 which is driven by a pinion 20 (Figure 3). The pinion has an hexagonal socket for receiving an Allen key 21 through the aperture 17. The rack 19 is provided with a fork-shaped probe 22 which has an insulating coating except at its tip. The probe can be driven, by rotation of the pinion with the Allen key, through the insulation 23, the screen 24 and the insulation 25 to straddle and contact the conductor 26. To facilitate penetration of the cable the forked ends ofthe probe 22 are sharpened.

Referring nowto Figures 3, 4 and 5, the rack is provided with a recess 28 which is engaged buy a peg 29 mounted in a recess in the enclosure portion 11 which peg is biased by a spring 30 towards the rack and has a sideways probjection 29a which comes into engagement in the recess. This peg secures the rack and its probe in the withdrawn position. The enclosure The drawing(s) originally filed was (were) informal and the print here reproduced is taken from a later filed formal copy.

portion 10 has a knock-down pin 31 which is arranged to depressthe peg 29 as a result of securement of the enclosure portions together thereby unlatching the rack and permitting its displacement by the pinion. A second peg 32, which is spring biased similarly to the peg 29, is arranged to engage a recess in the rack when it reaches a position where the probe 22 engages the innerconductor 26. This effects a latching action which prevents withdrawal ofthe probe and thereby maintains the electrical contact. The rack is prevented from moving beyond the engagement position by virtue ofthe projecting length of the probe 22. As can be seen from Figure 4, the end of the rack from which the probe projects is concave and of arcuate dimension conforming to the diameter of the outer insulation 23 of the coaxial cable.When the arcuate end ofthe rack engages the cable insulation, the probe 22 is fully engaged. The rack and pinion mechanism is enclosed within a cover plate 33.

In orderto provide a visual indication offull engagement of the mechanism, the rack is provided with an extension 34 which projects through a cut-out 35 in the cover plate 33. Full engagement of the rack and pinion mechanism is indicated by alignment of the end face 36 of the extension 34 with a face 37 on the enclosure portion 10. It will be appreciated that alternative visual indications could be provided for example a line marking on the rackvisiblethrough an aperture inthecover plate.

In order to screen the coaxial cable at the point at which piercing has been effected, an RF shield 38 is moulded into the two enclosure portions 10 and 11.

This can be seen in Figure 4. The shields 38 extend for the full depth and length ofthe enclosure portions and are made offor example expanded or perforated metalicsheet prestamped to the required profile.

The coaxial connector described has been designed to meet the need for a single action, reliable, pierce-connection for coaxial cable systems for exam ple, but not exclusively, the ethernet local area network system. Mounted to an ethernet transceiver the connector makes reliable and repeatable connections to the standard 50 ohms ethernetcable connecting directly on the printed circuit board by means of 0.6 mm square posts which can be seen in Figure 1 to mate with printed circuit board sockets.

Claims

1. An electrical connectorfor making a connection to a screened electrical cable, in which the connector comprises a two-part enclosure provided with a pair of mutually insulated terminal probes adapted, when the parts are closed onto a cable and mutually secured, to penetrate the cable insulation and make contact one with the screen and one with the inner conductor of the cable, the probe which makes contact with the inner conductor being displaceable in the enclosure to make contact with the inner conductor afterthe two parts have been mutually secured.

2. An electrical connector as claimed in claim 1, in which the centre probe is in the form of a partially insulated fork such that contact areas on the inside of each leg make electrical contact only with the centre conductor.

3. An electrical connector as claimed in claim 1, wherein the probe which makes contact with the inner conductor is displaceable by an actuating mechanism.

4. An electrical connector as claimed in claim 1,2 or3, wherein the actuating mechanism is a rack and pinion device.

5. An electrical connector as claimed in any one of the preceding claims, wherein latch means is provided for preventing displacement of the probe which makes contact with the inner conductor until the two parts of the enclosure are mutually secured.

6. An electrical connector as claimed in any one of the preceding claims, including stop means for limiting displacement ofthe probe beyond a position ofengagementwith the inner conductor.

7. An electrical connector as claimed in any one of the preceding claims, including a latch for retaining the probe in its fully displaced position thereby to retain the probe in engagement with the inner conductor.

8. An electrical connector as claimed in any one of the preceding claims, including a visual indicator of displacement of the probe to the position of engagementwith the inner conductor.

9. An electrical connector as claimed in any one of the preceding claims, wherein the probe for engage ment with the screen of the cable is arranged to penetratetheinsulation and contactthescreen asa result of closure of the enclosure parts onto the cable.

10. An electrical connector as claimed in any one ofthe preceding claims wherein there is provided an additional screen probesimilarto and spaced from the first screen probe,the probe for engaging the inner conductor of the cable being disposed therebetween.

11. An electrical connector as claimed in any one ofthe preceding claims, wherein the probes are coupled to terminals for connection to an external circuitwhich terminals extend in use radiallyofthe cable and an RF screen is provided in the enclosure which in use extends longitudinally of the cable.

12. An electrical connector substantially as described herein with reference to the drawings.