GB2109177A - Improvements in or relating to an electrical connector - Google Patents

Abstract

An electrical connector is provided for connecting a wire (23), such as a wire forming part of a winding of a motor, to a connector such as a spade terminal. The connector comprises a housing (3) defining an opened mouthed cavity and a contact element (2) dimensioned to be inserted in the cavity. As the contact element is inserted in the cavity it traps and contacts the wire. in one embodiment the contact element scrapes lacquer off the wire as the contact element is inserted into the cavity. The contact element is provided with a spring finger (21) to engage the connector element. <IMAGE>

Description

SPECIFICATION Improvements in or relating to an electrical connector This invention relates to an electrical connector.

In the manufacture of many items of electrical equipment, and also in utilising the electrical equipment, it is often necessary to establish a connection between two or more electrical conductors. As one example of this need, reference may be made to a field wound electric motor, where it is necessary to provide a connection between the windings of the coil of the motor and an electrical supply.

The present invention seeks to provide a connector which can be utilised to connect electrical conductors.

According to this invention there is provided an electrical connector for connecting a wire to a connector element, said connector comprising a housing defining an open-mouthed cavity, a contact element dimensioned to be inserted into the said cavity, said contact element having a contact portion adapted to trap said wire against a face within the cavity as the contact element is inserted into the cavity and thereby establish electrical connection between the wire and the said contact element, said contact element also being provided with means to establish a connection with said connector element.

Preferably said cavity is defined by four sidewalls and is substantially rectangular or square. Advantageously the said face within the cavity is a vertical sidewall face, or the like, and conveniently the inner face of the sidewall of the cavity opposite said portion of the contact element is provided with a groove to receive said wire. Preferably the inner face of the sidewall of said cavity adjacent said portion of the contact element is also provided with a groove to partially receive the wire. Conveniently notches are provided in the upper edges of said side walls which define said open mouth, and one said notch on the sidewall opposite said portion of the contact element may be provided with a slot at the lower edge thereof. In one embodiment at least said notch is aligned with a said groove, the groove extending downwardly from the nadir of the notch.Preferably each notch is aligned with a respective groove, the groove aligned with said notch having a slot at the lower edge thereof being deeper than the other said groove.

Advantageously said contact element comprises a base portion and two upstanding arms, one of said upstanding arms carrying said contact portion. Said one upstanding arm may be provided with a scraper portion located beneath the contact portion adapted to scrape insulating material from said wire when the contact element is inserted into the cavity. The scraper portion may be constituted by an outwardly deflected tang having a sharp edge to contact the wire, defined by two vertical slits and a transverse slit joining the tops of the two vertical slits. In an alternative embodiment the scraper portion comprises a sharp edge formed by an aperture provided in the contact element at the junction of said one upstanding arm and the base portion.Preferably said one upstanding arm portion has lesser width than the base portion so that the arm portion is resilient relative to the base portion, and said one arm is resiliently biassed against an adjacent face within the cavity when the contact element has been inserted into the cavity. It is preferred that said one arm is deflected away from a position in which it is perpendicular to the base before the contact element is inserted into the said cavity.

The contact element may be provided with means to retain the contact element in position within the housing, such as staking lugs protruding from the second upstanding arm. The second upstanding arm may carry a downwardly inclined finger which terminates adjacent the inner face of the first upstanding arm, and the finger may have lesser width than the second upstanding arm and the base.

This enables a special tool to be utilised to insert the contact element into the recess, the tool straddling the arm portion and contacting the base portion of the contact element.

The contact portion may be constituted by a protrusion formed on the said one arm, or by a substantially flat face on said one arm.

Preferably a spacer element is provided dimensioned to be inserted into the cavity before the contact element is inserted in the cavity. The spacer element may be metallic and may comprise or include a plate located between one wall of the cavity and said contact element, and may thus comprise a base and two upstanding arms constituting said plate, and the other being provided with an axially extending recess, defining a groove.

The invention also relates to an electrical connector as described above, in combination with a wire, the thickness of the wire being greater than the thickness of the slot and also the depth of the groove aligned with the slot being greater than the thickness of the wire. Preferably the depth of the groove opposite the slot is less than the thickness of the wire. Preferably the wire is lacquered insulated wire, and when the wire has been laid across said notches, a fixed end of the wire being on the slot-less notch, and a free end portion of the wire being in the said slot, the ciontact element may be inserted into said recess, moving the wire into said groove, the scraper element scraping insulation from the wire, and the contact element being brought into contact with the bared wire.

A connector as described above may be provided in combination with a wire wherein means have been used to clamp part of the wire against movement relative to the housing as the contact element has been introduced to the housing.

Preferably said means comprise means which clamp the wire against the housing.

Conveniently the clamping means comprise means to kink the wire about a corner of the housing.

Advantageously said means comprise a spring biassed sleeve mounted on the tool that inserts the contact element into the housing.

This invention also relates to a contact element for a connector as described above.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is an exploded view of the contact element and housing of a first embodiment of a connector in accordance with the invention; Figure 2 is a part-cut-away perspective view of the housing and contact element of the connector of Figure 1, during their assembly together; Figure 3 is a cross-sectional view of the connector of Figures 1 and 2 when assembled; Figure 4 is an exploded view of a contact element housing and spacer element of a second embodiment of the invention; Figure 5 is a part cut away perspective view of the connector of Figure 4 during its assembly;; Figure 6 is an enlarged underneath perspective view of part of the contact element of the connector of Figures 4 and 5; Figure 7 is a cross-sectional view of the connector of Figures 5 and 6, when assembled illustrating in phantom a tool used during assembly, part of the figure being shown again as an enlarged scale; and Figure 8 is a diagrammatic view of an electric motor provided with connectors in accordance with the invention.

Referring initially to Figures 1 to 3 of the accompanying drawings a first embodiment of a connector in accordance with the present invention comprises firstly a housing 1 which defines a cavity and secondly a metallic contact element 2 adapted to be inserted into the housing. The metallic contact element is initially provided in a condition which is illustrated most clearly in Figure 2 of the accompanying drawings, and when the metallic contact element is inserted into the housing, as will be described hereinafter, the metallic contact element then has the configuration illustrated most clearly in Figures 1 and Figure 3.

The housing 1 is preferably moulded of a plastics material such as 30% glass filled "Valox" 420 SEO, or a polyester moulding grade plastic based on poly(butyleneterephthalate) reinforced with 30% short glass fibres and sold under the Trade Mark "ARNITE" by Akzo Plastics of Arnhem, Holland.

These plastics materials are capable of withstanding a high temperature, but are relatively soft, and are electrically insulating materials. The housing 1 comprises four upstanding side walls 3 which are located in a substantially rectangular or square configuration, the side walls thus defining between them a substantially rectangular or square cavity 4 having an open mouth at the top. The bottom of the cavity may be closed. The tops of the side walls each have a planar horizontal outer portion 5 and a chamfered inner portion 6. The chamfered portions thus define the open mouth of the cavity and serve to guide the metallic contact element 2 when it is inserted into the cavity, as will be described hereinafter in greater detail.

One sidewall of the cavity is provided with a "V" shaped notch 7, (although the notch could be rectangular) formed in the upper edge of the wall and the opposite sidewall of the cavity is provided with a corresponding "V" shaped notch 8, this notch 8 terminating in a slot 9, which extends downwardly from the nadir of the notch 8. Formed on the inner faces of the two side walls of the cavity which carry the notches 7 and 8 are square or rectangular cross-sectioned grooves 10, 11, these grooves extending vertically downwardly from the nadir of the notch 7 and from the nadir of the slot 10 respectively.

The groove 10 is of lesser depth than the groove 11.

The housing 1 is to be utilised, in conjunction with the metallic contact element 2, to trap a metallic wire 12, so that the wire is retained in position, and so that electrical contact is established between the wire and the contact element 2. The metallic wire is, in the present embodiment of the invention, a very thin wire which is coated with laquer or enamel, which constitutes an insulating coating on the wire.

Such a wire may be, for example, a wire forming part of a coil of a motor. It is to be noted, at this stage, that the slot 9 has a width which is slightly less than the diameter of the wire. It is also to be noted that the groove 11 has a depth which is at least equal to the diameter of the wire, whereas the groove 10 has a depth which is less than the diameter of the wire.

The reason for these specific dimensions will become apparent during the following description of the invention.

The metallic contact element 2 is formed from a strip of metal such as phosphor-bronze, or beryllium copper, our a composite alloy of these materials, or some other suitable metal, such as brass. The contact element 2 has a substantially horizontal square or rectangular base portion 13. Upstanding from one side edge of the base portion 13 is a first planar arm 14, the arm 14 having a width which is slightly less than the width of the base portion 13.

Thus two shoulders 15 are defined between the arm portion and the base. In the initial condition of the contact element the arm 14 is not perpendicular to the base, but is inclined slightly away from the base.

Located towards the bottom of the upstanding arm portion 14 is a scraper element 16. This scraper element is formed by two vertical slits formed in the arm portion and a transverse slit interconnecting the uppermost ends of the two vertical slits, the slits defining a tang which is deflected outwardly from the vertical plane of the arm 14, the resultant curved tang thus protruding from the face of the arm that faces away from the base 13. Thus a horizontal sharp edge 17 protrudes outwardly from the plane of the arm 14. As will be described hereinafter this tang acts as a scraper.

Towards the uppermost edge of the arm 14, the arm is shaped to define a protruding contact portion 18, this protruding contact portion being of substantially arcuate form, when viewed in plan.

At the side edge of the base portion 13 remote from the upstanding arm 14 there is a second upstanding planar arm 19 having an overall width which is equal to the width of the base portion 13.

This arm 19 is perpendicular to the base 13. Two triangular protruding staking lugs 20 are provided adjacent the top of the arm 19, the lugs being in the plane of the arm, but protruding beyond the side edges of the arm. Extending from the top of the arm 19 is a relatively narrow finger 21. Thus the width of the finger 21 is significantly less than the width of the arm portion 19, and is thus significantly less than the width of the base 13, and is also less than the width of the first arm 14. The finger 21 initially protrudes upwardly and then curves so that the finger is directed downwardly towards the first upstanding arm 14. The finger 21 terminates, at its lower edge in a downwardly deflected lip 22.This lip 22 is spring biassed, by the nature of the curve of the finger 21, into contact with the first arm 14 when the contact element 2 has been inserted into the housing 1, as will be described hereinafter.

Having described the structure of one embodiment of the invention, the way in which the illustrated connector is connected to a wire will now be described.

The connector is to be connected to a wire 12 which is a laquer coated wire. In the described embodiment one end 23 of the wire is fixed in positon (for example by being wound to form the coil of a field wound motor) and the other end of the wire 24 is free. The wire is located in position so that a portion of the wire adjacent the fixed end of the wire passes through the "V" shaped notch 7, the wire then extending across the open mouth of the cavity 4 defined by the side walls of the housing, a portion adjacent the free end of the wire being inserted through the "V" shaped notch 8 and trapped within the slot 9. The slot 9 has a width which is less than the diameter of the wire and thus the slot 9 retains the wire relatively firmly, although the wire can be drawn through the slot, with the slot exerting a frictional force on the wire, and this force resists the movement of the wire.

As has been mentioned above, the metallic contact element 2 initially has the configuration illustrated in Figure 2. Thus the arm 14 is, in this configuration, not parallel with the arm 19, but is inclined outwardly. The metallic contact element, whilst in this condition, is urged into the cavity 4 defined by four side walls of the housing. The chamfered portion 6 at the top of each side wall serves to guide the metallic contact element into the desired position. The metallic contact element may be inserted into the required position with the aid of a tool which comprises a fork having two prongs which are spaced sufficiently far apart to be located straddling the downwardly inclined finger 21, the prongs engaging the base 13 of the metallic contact element.Thus when a force is applied to the tool the force is transmitted to the base of the contact element and the contact element is thus smoothly urged into the cavity with the housing.

As the contact element is introduced into the cavity within the housing, so initially the wire 12 becomes tensioned, and subsequently the free end of the wire slips through the slot 9, although the slot 9 does resist this movement. Thus the portion of the wire within the recess 4 is kept under tension at all times. As the metallic contact element is inserted further into the housing, the wire becomes accom modated within the vertical channels 10 and 11.

Since the groove 11 is of greater depth than the diameter of the wire, the wire is free to move within that groove, and the wire within the groove does not engage the metallic contact element. However, since the groove 10 has a depth which is less than the diameter of the wire, a portion of the wire protrudes beyond that groove, and as the metallic contact element is inserted into the recess 4, so the sharp edge 17 of the scraper element 16 contacts the protruding portion of the wire, and serves to scrape the insulating laquer off the wire, thus baring the metal of the wire. This can be seen most clearly in Figure 3. As the contact element 2 is inserted into the cavity in the housing, so the first arm 14 is moved to a position in which it is perpendicular to the base.

Thus the arm is moved and is deformed, and thus there is a resilient bias which is biassing the arm back towards its initial inclined condition. This urges the scraper tang 16 and the contact portion 18 of the arm 14 into firm contact with the wire 12. Since the arm 14 is of less width than the base 13, it is the arm 14 that is deformed and not the base 13.

As the metallic contact element is finally being inserted into position within the housing the staking lugs 20 will bite into the plastics material forming the housing and will thus serve to secure the metallic contact element in position.

When the metallic contact element has been fuily inserted into the housing, as shown in Figure 3, it can be seen that the contact portion 18 of the upstanding arm 14 is in firm contact with the bared portion of the wire,and thus a good electrical contact exists between the wire 12 and the contact element 21.

When the metallic contact element has been positioned as described above further contact can be made with the metallic contact element by means, for example, of a spade terminal, or other flat terminal, which can be inserted between the free end 22 of the downwardly inclined finger 21 and the upstanding arm 14, the terminal being inserted in the direction of the arrow 25 as shown in Figure 3.

The finger 21 will deflect downwardly as the terminal is inserted in position, but the inherent resilience of the finger 21 will ensure that a firm contact is established. Of course, a further wire could be utilised instead of the spade or other flat terminal although, in other embodiments of the invention, various different devices could be provided instead of the resilient finger 21 to establish further contact with an appropriate contact member that is to brought into electrical contact with the wire 12.

Figures 4 to 7 illustrate a second embodiment of the invention which incorporates many features that are different from the corresponding features of the embodiments shown in Figures 1 to 3. It is to be appreciated that various features of the embodiment about to be described could be replaced by the corresponding features of the embodiment shown in Figures 1 to 3 and similarly features present in the embodiment shown in Figures 1 to 3 could be substituted by features present in the now-to-bedescribed embodiment.

Turning now to Figures 4 to 7 it is to be noted that the illustrated embodiment of the invention comprises a housing 26, a metallic contact element 27 and a spacer element 28.

The housing 26 is preferably moulded of a plastics material such as 30% glass filled "Valox" 420 SEO, or the material sold under the Trade Mark "ARNITE" as mentioned above. The housing 26 comprises 4 upstanding side walls 29 which are located in a substantially rectangular or square configuration, the side walls thus defining between them a substantially rectangular or square cavity 30 having an open mouth at the top. The bottom of the cavity may be closed. Two opposed side walls each carry a centrally located inwardly directed guide rib 31. The tops of the side walls each have a planar horizontal outer portion 32 and a chamfered inner portion 33.

The chamfered portions thus define the open mouth of the cavity and serve to guide the spacer element 28 and the metallic contact element 29 when they are respectively inserted into the cavity.

The two opposed side walls of the cavity do not carry the inwardly directed guide ribs 31 and are each provided with a centrally disposed "V" shaped notch 34,35 in the upper edge of the side-wall. The notches 34, 35 are aligned.

The metallic spacer element 28 has a substantially square or rectangular base 36 with two notches or recesses 37 formed in two opposed side edges thereof. Each of the remaining edges of the base 36 is provided with an upstanding arm 38. Each arm 38 has two outwardly directed substantially triangular staking lugs 39 provided adjacent the top edge thereof, and the top edge 40 of each arm is chamfered. A rectangular recess 41 is provided in the centre of one upstanding arm and again the portion of the arm 42 defining the lowermost edge of the recess 41 is chamfered. A larger recess 41a is provided in the centre of the other upstanding arm, and extending over the whole height of the arm and partly across the base 36.

The spacer element is dimensioned to be a snug fit within the cavity 30, and it will be appreciated that when the spacer element is insulated into the cavity the recesses 37 in the base of the spacer element are co-aligned with the guide ribs 31 provided in the cavity and the spacer element is then inserted downwardly into the cavity. During this insertion process the staking lugs 39 will bite into the plastics material constituting the housing 26 and thus the metallic spacer element will be retained securely in position.

In an alternative embodiment (not shown) the spacer element may comprise merely a flat plate having the same configuration as the left-hand arm 38 shown in Figure 4.

The metallic contact element 27 is formed from a strip of metal such as phosphor-bronze or beryllium copper or a composite alloy of these materials, or brass. The contact element 27 has a substantially horizontal square or rectangular base portion 43.

Recesses 44 are provided in two opposed side edges of the base 43. The other two side edges support respective upstanding arms. Afirst upstanding arm 45 has a width which is slightly less than the width of the base portion 43 and thus shoulders 46 are defined between the arm portion and the base. The arm 45 is substantially planar.

The second upstanding arm 47 which extends upwardly from the side of the base 43 that is opposite to the arm 45, is constituted by a planar portion that is substantially perpendicular to the base 43. Two triangular protruding staking lugs 48 are provided adjacent the top of the arm 47, the lugs being in the plane of the arm but protruding beyond the side edges of the arm. Extending from the top of the arm 47 is a relatively narrow finger 49. Thus the width of the finger 49 is significantly less than the width of the arm portion 19 and is also less than the width of the base 43 and is also less than the width of the base 45. The finger 49 terminates, at its lower end, in a portion 50 that has substantially the same width as the arm 45. The finger 49 initially protrudes upwardly and then curves so that the finger is directed downwardly towards the first upstanding arm 45.Thus the terminal portion 50 is located immediately adjacent the inner face of the arm 45.

The terminal portion 50 is curved inwardly, and this curved portion is resiliently biassed against the inner face of the first arm 45 by the natural resilience of the finger 49.

An aperture 51 is formed in the metallic contact element 27, and in the assembled contact element the aperture 51 (which is shown most clearly in Figure 6) is located at the junction between the base 43 and the first arm 45. The aperture 51 may be cut or stamped into the strip from which the contact element 27 is formed before the arm 45 is bent to be perpendicular to the base 43. In any event it is to be understood that the aperture 51 effectively defines two sharp edges 52, 53 and when the contact element 27 is inserted into the housing (as will be described hereinafter) a wire 54 will be drawn past the sharp edges 52, 53 and any laquer coating present on the wire will be scraped off.

When the connector illustrated in Figures 4 to 7 is to be assembled initially the spacer element is inserted in position in the cavity defined within the housing 26. Any appropriate tool may be utilised, and the spacer element will be held in the desired position firstly by the cooperation of the recesses 37 in the base 36 of the spacer element with the protruding lips 31 provided on the said two opposed side walls of the cavity, and also by the staking lugs 39 biting into the material of the housing 26.

When the spacer element has been located in position a wire 54 to which connection is to be made is stretched across the open mouth of the cavity 30 formed within the housing, the wire merely resting loosely in the "V" notches 34,35. It is to be noted that the recesses 41 formed in the upstanding arms 38 of the spacer element are effectively aligned with the "V" notches 34,35.

The metallic contact element 27 is then introduced into the cavity with a two-pronged fork as described above. The two-pronged fork is illustrated in phantom in Figure 7, one prong being indicated by the reference numeral 55. A spring-loaded sleeve 56 is mounted around the two-pronged fork 55, this sleeve being adapted to be resiliently biassed into contact with the top edge of the housing 26 whilst the prongs 55 are driving the contact element 27 into the housing. As can be seen most clearly in the portion of Figure 7 that has been enlarged the sleeve 56 has, on one side thereof a downwardly protruding lip 57, this lip 57 being positioned to be brought substantially into abutment with the exterior of the housing 26 adjacent the "V" groove 34.When a wire 54 has been placed across the "V" grooves 34, 35 and a metallic contact element 27 is to be inserted into the housing the sleeve 56 is brought into resilient engagement with the upper edge of the housing 26 and thus the lip 57 present on the sleeve 56 kinks the wire 54 in the region of the "V" groove 34, thus preventing movement of the wire in that region. The opposed side of the sleeve 56 has a triangular protrusion that is resiliently inserted into the "V" groove 35, and thus a frictional force is applied to the wire 54 in the region of that "V" groove 35.

As the metallic contact element is inserted into the housing by continued movement of the twopronged fork 55, the wire 54 is effectively drawn past the two sharp edges 52, 53 of the aperture 51. The wire is retained under tension and thus any laquer present on the wire is scraped from the wire. As the contact element moves downwardly the scraped wire is trapped between the first arm 45 and the adjacent arm 38 of the spacer element 28. It is to be appreciated that the first arm portion 45 may be slightly outwardly resiliently biassed to ensure that a good electrical contact is maintained.

The recesses 41 and 41a are provided in the arms 38 of the spacer element 36 to ensure that there is a good feed-in and feed-out for the wire 54 with regard to the cavity, and it is to be appreciated that the wire can move freely in the groove defined by the recess 41a in the spacer member 28.

It is to be understood that a plurality of wires may be trapped simultaneously by a connector as described with reference to Figures 4to 7. In such a case a plurality of wires will be located across the open mouth of the cavity 30 after the spacer element 28 has been inserted into position, and then the contact element 27 will be inserted in position as described above. The plurality of wires will be trapped by the lip 57 present on the sleeve 56 and all the wires will be scraped by the sharp edges defined by the aperture 51. Also each of the wires will be trapped in position.

A flat or spade terminal may be inserted between the end portion 50 of the resilient finger 49 and the inner face of the outstanding arm 45 of the contact element. The illustrated design of the end portion 50 facilitates the easy withdrawal and subsequent reinsertion of such a spade terminal.

The connectors described above must be carefully dimensioned to ensure that the connectors operate satisfactorily with wire of the required thickness. It is to be appreciated that if a very thick wire is to be utilised the various illustrated components may have very different dimensions as compared with when a very thin wire is to be utilised.

A connector as described with reference to Figures 4 to 7 may be devised to accommodate wires of different diameter. It is envisaged that any particular connector will be able to accommodate wires of varying diameter, by virtue of the design of the connector, in that the wires are all held firmiy against the sharp edges of the aperture 51 thus ensuring satisfactory scraping of the laquer. Thus a single connector may operate satisfactorily with wires in a diameter range of, say, 0.17 millimetres to 2.2 millimetres. However, it is to be appreciated that utilising a single tool for moulding the housing and a single tool for forming the metallic contact element 27 a plurality of spacer elements 28 of different thicknesses could be prepared.Thus the thickest spacer element would be utilised when wires of very small diameter are to be trapped and a spacer element of least thickness would be utilised when wires of greatest diameter have to be trapped. Thus, with a single moulding tool and a single contact element making tool, a range of connectors can be readily manufactured but can accommodate wires having a thickness within a very wide range. The range may be, at least, 0.18 millimetres to 0.335 millimetres diameter, and it is believed that thicker wires may be utilised satisfactorily.

Figure 8 illustrates, purely by way of example, an electric motor provided with a plurality of connectors 58 of either of the two types described above, and it can be seen that the housings of these connectors are formed on an integral base 59. A switch element 60 is provided, which has a control switch 61,this element including a plurality of spade terminals some of which, 62 are illustrated. As the switch element 60 is inserted into position, the spade terminals 62 become inserted into the appropriate housings, thus establishing contact with the wires of the motor.

It is to be appreciated that whilst two embodiments of the invention has been described many modifications may be made without departing from the invention.

Whilst the housing has been described as being made of a plastics material it is to be appreciated that the housing may, if desired, be made wholly of a conductive material, such as an appropriate metal, or the housing may be a composite structure, having an inner conductive material layer and an outer insulating material layer. The function of the housing is to provide a receptacle for the metallic contact element and to define means to hold the wire whilst it is scraped, and whilst the contact portion of the contact element is brought into contact with it.

Whilst, in each case, the metallic contact element has been shown as being retained in position within the housing by means of staking lugs which bite or cut into the material of the housing, any other appropriate device may be utilised to retain the metallic element in position within the housing.

Thus the inner faces of one or more walls of the housing may be provided with protrusions to engage corresponding recesses formed in the contact element, when the contact element is fully inserted into the cavity in the housing.

It is to be appreciated that whilst the present invention has been described with specific reference to the use of laquered wire, connectors in accordance with the invention may be utilised in connection with wires which are not laquered, and in such cases the scraper element may be omitted.

It is to be noted that in the described embodiments of the invention the lowermost free edge of the downwardly inclined finger is curved to form the lip.

This facilitates the retraction of spade terminal once the spade terminal has been inserted in position with the connector. It is to be appreciated that this is not essential, and the downwardly inclined finger could terminate with a sharp edge which would serve securely to trap and retain a wire or terminal inserted in position in the connector. This may prove to be desirable in certain circumstances.

Claims (36)

1. An electrical connector for connecting a wire to a connector element, said connector comprising a housing defining an open-mouthed cavity, a contact element dimensioned to be inserted into the said cavity, said contact element having a contact portion adapted to trap said wire against a face within the cavity as the contact element is inserted into the cavity and thereby establish electrical connection between the wire and the said contact element, said contact element also being provided with means to establish a connection with said connector element.

2. An electrical connector according to claim 1, wherein said cavity is defined by four sidewalls and is substantially rectangular or square.

3. An electrical connector according to claim 2, wherein the said face within the cavity is a vertical sidewall face, or the like, and the inner face of the sidewall of the cavity opposite said portion of the contact element is provided with a groove to receive said wire.

4. An electrical connector according to any one of the preceding claims wherein the inner face of the sidewall of said cavity adjacent said portion of the contact element is provided with a groove to partially receive the wire.

5. An electrical connector according to any one of claims 2 to 4, wherein notches are provided in the upper edges of said side walls which define said open mouth.

6. An electrical connector according to claim 5, wherein one said notch on the sidewall opposite said portion of the contact element is provided with a slot at the lower edge thereof.

7. An electrical connector according to claim 6 as dependent upon claim 3 or 4, wherein at least said notch is aligned with a said groove, the groove extending downwardly from the nadir of the notch.

8. An electrical connector according to claim 7 wherein each notch is aligned with a respective groove, the groove aligned with said notch having a slot at the lower edge thereof being deeper than the other said groove.

9. An electrical connector according to any one of claims 1 to 8, wherein said contact element comprises a base portion and two upstanding arms, one of said upstanding arms carrying said contact portion.

10. An electrical connector according to claim 9, wherein said one upstanding arm is provided with a scraper portion located beneath the contact portion adapted to scrape insulating material from said wire when the contact element is inserted into the cavity.

11. An electrical connector according to claim 10, wherein the scraper portion is constituted by an outwardly deflected tang having a sharp edge to contact the wire, defined by two vertical slits and a transverse slit joining the tops ofthetwovertical slits.

12. An electrical connector according to claim 10, wherein the scraper portion comprises a sharp edge formed by an aperture provided in the contact element at the junction of said one upstanding arm and the base portion.

13. An electrical connector according to any one of claims 9 to 12, wherein said one upstanding arm portion has lesser width than the base portion so that the arm portion is resilient relative to the base portion.

14. An electrical connector according to any one of claims 9 to 13, wherein said one arm is resiliently biassed against an adjacent face within the cavity when the contact element has been inserted into the cavity.

15. An electrical connector according to claim 14, wherein said one arm is deflected away from a position in which it is perpendicular to the base before the contact element is inserted into the said cavity.

16. An electrical connector according to any one of claims 9 to 15, wherein the contact element is provided with means to retain the contact element in position within the housing.

17. An electrical connector according to claim 16, wherein said retaining means comprise staking lugs protruding from the second upstanding arm.

18. An electrical connector according to any one of claims 9 to 17, wherein the second upstanding arm carries a downwardly inclined finger which terminates adjacent the inner face of the first upstanding arm.

19. An electrical connector according to claim 18, wherein the finger has lesser width than the second upstanding arm and the base.

20. An electrical connector according to any one of claims 9 to 19, wherein the contact portion is constituted by a protrusion formed on the said one arm.

21. An electrical connector according to any one of claims 9 to 19, wherein the contact portion is constituted by a substantially flat face of said one arm.

22. An electrical connector according to any one of the preceding claims wherein a spacer element is provided dimensioned to be inserted into the cavity before the contact element is inserted in the cavity.

23. An electrical connector according to claim 22 wherein said spacer element is metallic.

24. An electrical connector element according to claim 22 or 23 wherein said element comprises or includes a plate located between one wall of the cavity and said contact element.

25. An electrical connector according to claim 24, wherein the spacer element comprises a base and two upstanding arms, one of said arms constituting said plate, and the other being provided with an axially extending recess, defining a groove.

26. An electrical connector according to any one of claims 14 to 24 as dependent upon claim 6, in combination with a wire, the thickness of the wire being greater than the thickness of the slot and also the depth of the groove aligned with the slot being greater than the thickness of the wire, the depth of the groove opposite the slot is less than the thickness of the wire.

27. An electrical connector according to claim 25, as dependent upon claim 8 wherein the depth of the groove opposite the slot is less than the thickness of the wire.

28. An electrical connector according to claim 26 or 27, wherein the wire is a laquered insulated wire, and wherein the wire has been laid across said notches, a fixed end of the wire being on the slot-less notch, and a free end portion of the wire being in the said slot, and wherein the contact element has been inserted into said recess, moving the wire into said groove, the scraper element scraping insulation from the wire, and the contact element then being brought into contact with the bared wire.

29. An electrical connector according to any one of the preceding claims in combination with a wire wherein means have been used to clamp part of the wire against movement relative to the housing as the contact element has been introduced to the housing.

30. An electrical connector according to claim 29, wherein said means comprise means which clamp the wire against the housing.

31. An electrical connector according to claim 30, wherein the clamping means comprise means to kink the wire about a corner of the housing.

32. An electrical connector according to claim 29, 30 or 31, wherein said means comprise a spring biassed sleeve mounted on the tool that inserts the contact element into the housing.

33. An electrical connector substantially as described with reference to and as shown in Figures 1 to 3 of the accompanying drawings.

34. An electrical connector substantially as described with reference to and as shown in Figures 4 to 7 of the accompanying drawings.

35. A contact element for a connector according to any one of the preceding claims.

36. Any novel feature or combination of features described herein.