GB2029650A

GB2029650A - Electrical connectors

Info

Publication number: GB2029650A
Application number: GB7834896A
Authority: GB
Original assignee: Pressac Ltd
Current assignee: Pressac Ltd
Priority date: 1978-08-29
Filing date: 1978-08-29
Publication date: 1980-03-19

Abstract

An electrical connector of the kind wherein an electrical connection between a contact of the connector and an insulation-covered wire is achieved by providing the contact with a portion that can be caused to penetrate the insulation and be forced into electrical engagement with the wire itself, is formed in two parts, the first of which comprises a housing 7 accommodating at least one contact 1 fitted with a rigid pin 2, and the other part consists of a casing 13 adapted to receive immovably in a bore 14 thereof a doubled-back or angularly disposed portion 12a of one or more insulation covered wires 12. When the two parts of the connector are interengaged by sliding them together a contact pin 2 of the first part is very accurately axially aligned with a bent over end portion 12a of a wire 12 so that after the pin 2 penetrates the insulation of the wire at the bend during engagement of the two parts of the connector, the pin 2 passes axially and longitudinally into the end portion 12a of the wire so as to make considerable and intimate contact therewith. <IMAGE>

Description

SPECIFICATION Improvements in or relating to electrical connectors This invention relates to electrical connectors of the kind wherein electrical contact is made with the core of an insulation covered wire by penetration of the insulation thereof by prong members made of electrically conductive material. Such a connection can also be achieved by what is termed the "fork system" which literally cuts through the insulation of a wire but only achieves a very small area of electrical contact with the core of the wire. These known methods have a certain disadvantage in that should any tension such as tugging or snagging be applied to the conductor wire it is quite possible for the insulation to be stripped away and result in a faulty electrical connection.Also stranded cores are held in a roughly circular cross section by the insulation and can easily be distorted into an oval section thereby reducing the effectiveness of the electrical connection between the fork and conductors.

The object of the present invention is to provide a connector of this general kind wherein the above mentioned disadvantage is avoided.

According to the present invention there is provided an electrical connector wherein one part is fitted with one or more rigidly located contact pins and the second part is adapted to receive a doubledback or angularly disposed end portion of one or more insulation-covered wires so that the core of the or each wire is in axial alignment with an associated contact pin when the two parts of the connector are engaged one with the other whereby said contact pin is caused to penetrate the insulation where it is doubled back or angularly disposed and pass axially into and along said core so as to make intimate electrical contact therewith.

According to a preferred embodiment of the invention the doubled-back or angularly disposed end portion of each wire is located in a bore in the second part of the connector and the diameter of this bore is such to ensure that it will allow for expansion of the wire, due to insertion of a contact pin, without splitting or fracturing the insulation but at the same time ensure that this doubled back portion is a tight close fit in the bore.

To enable the invention to be clearly understood and readily carried into effect preferred embodi mentsthereofwill now be described by way of example with reference to the accompanying draw ings wherein: Figures 1 and2 are a side view and a plan view respectively of the pin-like contact of a first part of the connector.

Figure 3 is a part-sectional side view showing said pin-like contact fitted in its housing.

Figure 3A is a sectional view of a casing in which has been positioned a doubled-back end portion of an insulation-covered conductor wire.

Figure 4 is a perspective view of said housing and which is designed to receive a plurality of said pin-like contacts.

Figure 5 is a perspective view of a complementary casing adapted to be fitted with a plurality of conductor wires.

Figure 5A is a plan view illustrating a constructional detail.

Figures 6and 7 are part sectional side views illustrating modifications.

Figures 8 to 11 are views illustrating a further modification and Figures 12 and 13 are views illustrating a development of the modification illustrated by Figures 8 to 11.

Referring firstly to Figures 1 to 3A of said drawings the contact is a two-part contact comprising a main part 1 of electrically conductive material to which is secured a thin strong contact pin 2 also of electrically conductive material, said pin 2 being slid through a small tubular part 3 until its inner end abuts a stop 4 so as to position the pin accurately with respect to the part 1 and then being immovably fixed to said part 1 by crimping the tubular part 3 on to the pin 1 as indicated at 5 and also by welding or soldering the pin to the part 1 as indicated at 6.

A plurality of said pin-like contacts 2 are fitted in a housing 7 of insulating material and the main part 1 of each contact is formed with a latch 8 and/or side barbs 9 that co-act with preformed abutments or detents on or in the moulded housing 7 so as to prevent unintentional separation of the contact from the housing 7.

The remaining part of the contact that extends in the opposite direction to that pointed to by the pin 2 may be constructed in any required manner to suit the way in which the contact is to be electrically connected to a lead. In the particular embodiment illustrated this remaining part of the contact is formed with a flexible looped portion 10 that is compressed from its free position as illustrated in Figure 1 to a position as shown in Figure 3 when it is inserted into the housing 7 and thereby caused to press against the roof of the housing so as to yield and be urged tightly against a blade terminal (not shown) of a lead and that is inserted through an opening 11 in the housing 7 and sandwiched between said looped portion 10 and the roof of the housing to result in a good electrical connection.It is to be clearly understood that this particular arrangement is illustrated purely by way of example and may be replaced by any other appropriate connection for a lead.

Conductor wires 12 with the cores of which the contact pins 2 are to be engaged axially are housed in a casing 13 (Figures 3A and 5) formed with blind bores 14 in which doubed-back end portions 12a of the wires 12 are inserted. The diameter of each of these bores 14 is critical and is pre-determined so that each bore is sufficiently large to accommodate the doubled-back portion 1 2a of an insulated wire when an axially aligned contact pin 2 is inserted therein in a clean and efficient manner and slightly expanded thereby so that the insulation is a tight close fit and is supported and pressed around its complete circumference by the wall of the bore 14.

This virtually eliminates any risk of the insultion splitting when a pin 2 is inserted into a conductor wire so as to make electrical contact along the length of the wire core. In the unlikely event of the insulation splitting, the pressure applied thereto keeps it in position. On the other hand the size of the bore 14 must not be too small and make pininsertion difficult.

If necessary splines 14a (Figures 5 and 5A) may be provided that extend axially along the wall of each bore 14to facilitate centralisation of an insulated wire within the bore but in order also to avoid restriction of the necessary expansion which must take place when the pin of the contact is inserted.

The casing 13 is a sliding fit in the housing 7 and an integrally hinged lid 15 thereof is formed with holes 16 through which the contact pins 2 are guided and pierce and penetrate the insulation of the portion 1 2a of the conductor wire 12 and engage the core of the wire along the centre line thereof, said core, the hole 16 and the associated pin 2 all being aligned accurately axially. Guide lips 7a are provided on the housing 7 that co-act with the casing 13 when the two parts are slid together.

To ensure still further that each contact pin 2 is rigidly located and the axial centre line thereof maintained, the housing 7, as shown in Figure 4, has walls 17 between which the contacts are located formed with ribs 18 that provide grooves 19 between themselves and an outer wall of the housing in which can engage as a sliding-fit flanges 20 and 21 (Figure 2) provided at each side of the contact. The ends of the flanges 21 are chamferred at 22 to provide a lead to assist insertion of the contact into the housing 7. The grooves 19 extend into the housing 7 sufficiently to locate the contact correctly in the housing 7, the ends of the grooves 19 being shaped to act against the ends of the flanges 22 to provide a positive stop thus preventing possible damage to the contact during the wire piercing operation.

When conductor wires 12 are fitted to the casing 13 by first inserting the end 1 2a of each wire into a blind bore 14 the wire is then folded in the opposite direction in open channels 23 (Figure 5) in which position the wires are held immovable by integrally moulded gripping ribs 24.

It will be apparent that this method of loading the conductor wires 12 into the casing 13 provides means whereby the wires are not only held securely in position in the casing by the gripping ribs 24 but also when the unit is in use any snagging of a wire will not result in dislodging the wire completely from the bore 14. When the wires 12 have been fitted the pin guide plate 15 is then folded back in the direction of the arrow A (Figure 5) and the casing is advanced in the direction of the arrow B (Figures 3 and 3A) the pins 2 passing through the guide holes 16 and piercing the portions 12a of the insulation and being located snugly in the centre of the stranded wire conductor.Retaining latches 25 provided on the casing 13 engage in complementary apertures 26 provided on the housing 7 thus preventing uninten tional separation cf f the two parts of the connector.

The preferred material from which the housing 7 and casing 13 are produced is nylon or a similar flexible synthetic plastics material. The material shou!d be flexible so that when it is desired to disconnect the casing 13 it is only necessary to flex the side portions 27 of the housing 7 outwardly and withdraw the casing 13 from said housing.

The foregoing embodiment has been described by way of example and it is to be appreciated that modifications and variations thereof are possible within the scope of the invention. For instance as shown in Figure 6 in which the same reference numerals are used to indicate the similar parts the conductor wire 12 is bent downwardly from the casing 13 instead of back upon itself as illustrated in Figure 3A. With this modification the floor of the housing 7 can be slotted to take over the wire 12 when the housing 7 and the casing 13 are interengaged. The axial piercing of the part 12a of the wire 12 by the pin 2 is exactly the same as before.

Another slight modification is illustrated by Figure 7 according to which the pin 2 is directed at right angles to the main part 1 of the contact and the conductor wire is led away in a downward direction.

Also instead of making the lid 15 having the guide holes 16 for the pins 2 as hinged integral part of the casing 13, this lid may comprise a separate plate and provision made on the sides of the casing 13 for this plate to be retained by a suitable form of snap fastener.

Figures 8 to 11 illustrate a modified construction of the casing 13 to adapt it to receive the folded back ends of a plurality of wires 12 held together by a web 28 and known as a ribbon wire. To enable this to be achieved the casing is formed with a cavity shaped as illustrated to suit the cross section of ribbon wires, the bores 14 communicating with one another by intermediate spaces 1 4b in which the intermediate web portion 28 of the wires can engage. By this means a plurality of parallel side-by-side wires may be simultaneously loaded into the casing 13 that can then be engaged within the housing 7 as previously explained.

Figures 12 and 13 illustrate an arrangement similar to Figure 8 but wherein the casing 13 is formed with small wedge shape retaining projections 13a that press into the insulation of the wires so as to assist still further in securing the wires in position after assembly and when the casing 13 has been engaged with the housing 7. Similar projections 13a may also be formed on the housing 7 of the embodiment described with reference to Figures 1 to 7.

Claims

1. A two-part electrical connector wherein one part is fitted with one or more rigidly located contact pins and the second part is adapted to receive a doubled-back or angularly disposed end portion of one or more insulation covered wires so that the core of the or each wire is in axial alignment with an associated contact pin when the two parts of the connector are engaged one with the other whereby said contact pin is caused to penetrate the insulation where it is doubled back or angularly disposed and pass axially into and along said core so as to make intimate electrical contact therewith.

2. A connector as claimed in Claim 1, wherein the doubled-back or angularly disposed end portion of each wire is located in a bore in the second part of the connector and the diameter of this bore is such to ensure that it will allow for expansion of the wire, due to insertion of a contact pin, without splitting or fracturing the insulation but at the same time ensure that this doubled back portion is a tight close fit in the bore.

3. A connector as claimed in any of the preceding claims, whereinn adjacent bores of the second part communicate to form a cavity to suit the crosssection of ribbon wires consisting of a plurality of parallel side-by-side multi-stranded conductor wires.

Appendantclaims re-numbered.

3. A connector as claimed in Claim 1 or 2, wherein a wall or lid of the second part is formed with holes through which (when the parts are slid together) the contact pins of the first part are guided and each caused to penetrate the insulation of a bent back or angularly disposed end portion of a wire and engage the core of the wire along the centre line thereof, the arrangement being such that said core and the associated hole and contact pin are all caused to be axially aligned.

4. A connector as claimed in any of the preceding ciaims, wherein adjacent bores of the second part communicate to form a cavity to suit the crosssection of ribbon wires consisting of a plurality of parallel side-by-side conductor wires.

5. A connector as claimed in any of the preceding claims, wherein splines are provided that extend axially along the wall of each bore to facilitate centralisation of an insulated wire within the bore in order to avoid restriction of the necessary expansion which must take place when the pin of the contact is inserted.

6. A connector as claimed in any of the preceding claims, wherein said casing is formed with projections that press into the insulation of the wires when the casing is engaged in said housing so as to retain and securestill further the wires in position.

7. A connector as claimed in any of the preceding claims, wherein each contact is adapted to co-act with its housing to be correctly positioned and interlocked therewith and be held against relative movement and separation therefrom.

8. A connector as claimed in any of the preceding claims, wherein the two parts are adapted to be slid together and one ofthe parts provided with guide lips for locating the two parts accurately one relatively to the other.

9. A connector as claimed in any of the preceding claims wherein said parts are adapted to interlock when engaged to prevent unintentional separation thereof.

10. Atwo-part electrical connector constructed substantially as hereinbefore described with referpence to and as illustrated by Figures 1 to 5A, 6,7,8 and 9, or 12 and 13 of the accompanying drawings.

New claims or amendments to claims filed on 31.7.79 Superseded claims 1, 2,3 and 4 New or amended claims:

1. Atwo-part electrical connector wherein one part is fitted with one or more rigidly located contact pins and the second part is formed with a bore for receiving a doubled-back or angularly disposed end portion of one or more insulation-covered multistranded conductor wires so that the core of each said end portion of the or each wire is in axial alignment with an associated contact pin when the two parts of the connector are engaged one with the other whereby said contact pin is caused to penetrate the insulation of the doubled back or angularly disposed portion and pass axially into and along said portion of the core so as to make intimate electrical contact therewith the diameter of the bore in the second part of the connector for receiving the doubled-back or angularly disposed end portion of each wire being such to ensure that it will allow for expansion of the wire, due to insertion of a contact pin, without splitting or fracturing the insulation but at the same time ensure that this doubled back portion becomes a tight close fit in the bore.

2. A connector as claimed in Claim 1, wherein a wall or lid of the second part is formed with holes through which (when the parts are slid together) the contact pins of the first part are guided and each caused to penetrate the insulation of a bent back or angularly disposed end portion of a wire and engage the core of the wire along the centre line thereof, the arrangement being such that said core and the associated hole and contact pin are all caused to be axially aligned.