GB2209428A

GB2209428A - Shielding electrical leads

Info

Publication number: GB2209428A
Application number: GB8728791A
Authority: GB
Inventors: Brian Joynes
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1987-02-04
Filing date: 1987-12-09
Publication date: 1989-05-10
Also published as: GB8702499D0; GB2209428B; GB8728791D0

Abstract

A shielding tape (20, Fig 2) comprises plastics tape 22 provided with metallic coverings (24 and 26) and an adhesive layer (28). The longitudinal margins (30) of the tape (20) are formed with scallops (34) and are folded over towards each other. The scalloped form of the margins (30) inhibits the tape (20) from acting as a linear wave guide. The tape is used in a cable harness to shield a bundle (18) of insulated conductors (10) terminated to a shielded connector (2). The strands (44) of a grounding conductor (38) are wrapped about the conductors (10), the bundle twisted and the tape applied. The tape (20) connects with the shield (6) of the connector. <IMAGE>

Description

SHIELDING ELECTRICAL LEADS This invention relates to a method of shielding a bundle of insulated electrical leads terminated to electrical terminals of a shielded electrical connector, to a shielded electrical harness comprising a bundle of insulated electrical leads and to a length of shielding tape for shielding a bundle of electrical leads.

According to one aspect of the invention, in a method of shielding a bundle of insulated electrical leads which have been terminated to electrical terminals of an electrical connector encased in an electrically conductive shield, a tape of insulating material provided on at least one side thereof with a metallic covering is wrapped helically about the bundle of leads to enclose and thereby to shield them, with an adhesive surface of the tape thereagainst, and is electrically connected to the shield of the connector, and method a continuous series of indentations is formed in each longitudinal margin of the tape throughout its length and these margins are folded over towards each other to overlie that surface of the tape which is to engage the bundle of leads, before the tape is wrapped thereabout.

According to another aspect of the invention, a shielded electrical harness comprises a bundle of insulated electrical leads which have been terminated at each of their ends to the terminals of an electrical connector encased in an electrically conductive shield, the bundle of leads being enclosed by an insulating tape wrapped helically thereabout and at least one side of which is provided with a metallic covering which is electrically connected to the shield of the connector, the tape being secured about the bundle of leads by means of an adhesive, the or each metallic covering having been formed with a continuous series of indentations defining projections which extend normally of the length of the tape, the series of projections extending throughout the length of the tape and being adjacent to the bundle of leads.

The said indentations, which preferably define two opposed rows of scallops extending along the length of the tape, inhibit the tape from acting as a linear wave guide which would transmit unwanted electromagnetic energy along the bundle of leads.

Preferably, the tape is also wrapped about a multistranded grounding conductor, which is electrically connected to the connector shielding, and the strands of which are wrapped about the bundle of wires. The tape is also preferably wrapped about the connector shielding and about the connection between the grounding conductor and the shielding.

According to a further aspect of the invention, a length of synthetic plastics tape has on a side thereof a metallic shielding covering provided with an adhesive layer at least coextensive with the the longitudinal margins of the tape, said margins having been folded over towards oneanother so as to overlie the other side of the tape, each margin defining a row of projections, which row extends lengthwise of the tape and throughout its length, each projection extending from its margin towards the opposite margin.

For a better understanding of the invention, reference will now be made by way of example to the accompanying drawings in which: FIGURE 1 is an isometric view illustrating a method of shielding, by means of a specially prepared adhesive tape, a bundle of electrical leads each of which has been terminated to a terminal of a shielded electrical connector; and FIGURE 2 is a greatly enlarged fragmentary view of the tape prior to its preparation for use.

A shielded electrical connector 2 comprises an insulating housing 4 encased in a metal shield 6 and which contains electrical terminals 8 each of which has been electrically connected, for example, by means of a crimping operation, to one end of the electrically conductive core of an insulated electrical lead 10.

The housing 4 has a hood portion 12 for receiving a mating portion of a male electrical connector (not shown) and a rear portion 14 which is somewhat narrower than the hood portion 12.

The leads 10 extend to the terminals 8 from a helically wrapped bundle 18 of the leads 10, the other ends of the leads 10 being terminated to terminals of a second shielded connector (not shown) or to some other shielded connecting means.

A shielding tape 20 for shielding the bundle 18 of leads 10 comprises, as shown in Figure 2, a synthetic plastics tape 22 provided with metallic coverings 24 and 26, one on each side of the tape 20, the covering 26 having an impact adhesive layer 28.

In order to prepare the tape for use in shielding the bundle 18, its longitudinal margins 30 are, as shown in Figure 1, scalloped and folded over so as to overlie the metallic covering 24, so that the scalloped margins 30 cooperate to define a continuous series of regular indentations 32 extending throughout the length of the tape 20. The indentations 32 are defined between identical rounded projections 34, each projection 34 of one margin 30 being opposite to, and aiigned with, a projection 34 of the other margin 30. The margins 30 are covered by the adhesive layer 28, which can, if convenient, be applied to the metallic covering 26 only coextensively with the margins 30.

The shielding of the bundle 18 of leads 10 by means of the tape 20 will now be described. A multistranded grounding conductor 36 is initially electrically connected to the connector shield 6 by means of a screw 38 which is passed through a ring tongue 40 crimped to the conductor 36 and is then screwed into a hole 42 in the housing 4 to secure the ring tongue 40 thereto.

The strands 44 of the conductor 36 are then wrapped around the bundle 18 of leads 10 after which the tape 20 is wrapped helically thereabout as shown in Figure 1 to enclose the bundle 18 and so as to be secured thereto by means of the adhesive layer 28 on the margins 30. The bundle 18 is preferably twisted prior to the wrapping operation to bring together the loose leads adjacent to the housing 4. The tape 20 is also wrapped about the portion 14 of the housing 4 so as to cover the connection between the grounding conductor 36 and the shield 6.

The scalloped configuration of the metalized margins 30 inhibits the tape 20 from acting as a linear wave guide for unwanted electromagnetic signals.

Although it is usual for the leads of the bundle of leads to be helically wrapped about one another, in some cases it may not be convenient so to wrap the leads, and the leads may, for example, extend rectilinearly, in such a case.

Claims

CLAIMS:

1. A method of shielding a bundle of insulated electrical leads which have been terminated to electrical terminals of an electrical connector encased in an electrically conductive shield, in which method a tape of insulating material provided on at least one side thereof with a metallic covering is wrapped helically about the bundle of leads to enclose and thereby to shield them, with an adhesive surface of the tape thereagainst, and is electrically connected to the shield of the connector, and in which method a continuous series of indentations is formed in each longitudinal margin of the tape throughout its length and these margins are folded over towards each other to overlie that surface of the tape which is to engage the bundle of leads, before the tape is wrapped thereabout.

2. A method as claimed in claim 1, in which the strands of a multistranded grounding conductor are electrically connected to the shield of the connector and are wrapped about the bundle of leads prior to the tape being wrapped about said bundle.

3. A method as claimed in claim 2, in which the tape is wrapped about the shield of the connector so as to cover the connection between the shield and the grounding conductor.

4. A method as claimed in claim 1, 2, or 3, in which both sides of the tape are provided with metallic coverings, one of which is provided with adhesive layers coextensive with said margins, for securing the tape to the bundle of leads.

5. A method as claimed in any one of the preceding claims, in which the indentations are so formed in the longitudinal margins of the tape, as to define, when said margins have been folded over, a series of opposed, identical, rounded projectings, each projection extending normally of the length of the tape.

6. A shielded electrical harness comprising a bundle of insulated electrical leads which have been terminated at each of their ends to the terminals of an electrical connector encased in an electrically conductive shield, the bundle of leads being enclosed by an insulating tape wrapped helically thereabout and at least one side of which is provided with a metallic covering which is electrically connected to the shield of the connector, the tape being secured about the bundle of leads by means of an adhesive, the or each metallic covering having been formed with a continuous series of indentations defining projections which extend normally of the length of the tape, the series of projections extending throughout the length of the tape and being adjacent to the bundle of leads.

7. A harness as claimed in claim 6, in which the indentations are formed in longitudinal margins of the tape which have been folded over towards one another so as to be contiguous with that surface of the tape which is adjacent to the bundle of leads, a layer of an impact adhesive being provided on said margins.

8. A harness as claimed in claim 6 or 7, wherein the projections are identical rounded projections providing scallops in said margins, each projection of one margin being opposite to and extending towards a projection of the other margin.

9. A harness as claimed in claim 6, 7 or 8, in which the tape encloses a multistranded grounding conductor, the strands of which extend about the leads of the bundle and are electrically connected to the connector shield, the tape extending about the shield and covering the electrical connections between the strands and the shields.

10. A length of synthetic plastic tape having on a side thereof a metallic shielding covering provided with an adhesive layer at least coextensive with the longitudinal margins of the tape, said margins having been folded over towards oneanother so as to overlie the other side of the tape, each margin defining a row of projections, which row extends lengthwise of the tape and throughout its length, each projection extending from its margin towards the opposite margin.

11. A length of tape as claimed in claim 10, in which the projections are identical and are rounded, and extend normally of the tape.

12. A method of shielding a bundle of insulated electrical leads, substantially as hereinbefore described with reference to the accompanying drawings.

13. A shielded electrical harness, substantially as hereinbefore described with reference to the accompanying drawings.

14. A length of tape for shielding a bundle of insulated electrical leads, substantially as hereinbefore described with reference to the accompanying drawings.