GB2580436A

GB2580436A - Electrical connector

Info

Publication number: GB2580436A
Application number: GB1901300.2A
Authority: GB
Inventors: Mottram Christopher
Original assignee: Scolmore International Ltd
Current assignee: Scolmore International Ltd
Priority date: 2019-01-08
Filing date: 2019-01-30
Publication date: 2020-07-22
Anticipated expiration: 2039-01-30
Also published as: GB2580436B; GB201900236D0; GB201901300D0

Abstract

An electrical connector suitable for multi-core cables comprises a casing 10 having an entry port 11 through which at least one of a plurality of conductors may extend in to the casing 10, an interface formation 14 supported by the casing 10 to enable connection to another connector, and a terminal formation 13 to provide electrical connection between said conductor and the interface formation 14. The terminal formation 13 comprises a resiliently biased retention limb (figure 5, 25) having a distal end (figure 5, 36) which bears against an inserted conductor to hold the conductor firmly against the terminal formation 13 and resist withdrawal of the conductor. The connector further comprises a deflector (figure 6, 40) which is operable externally of the casing 10 and which bears against the resiliently biased retention limb, where the distal end of the resiliently biased limb moves away from the confronting surface of the terminal formation through pressing of the deflector, allowing withdrawal or insertion of a conductor.

Description

Electrical Connector This invention relates to an electrical connector and in particular, but not exclusively, to an electrical connector for connection to the ends of a plurality of flexible conductors such as individual wires or the conductors of multi-core cables.

It relates in particular, though not exclusively, to an electrical connector suitable for use in domestic or commercial premises.

Commonly connectors for electrical installations in domestic and commercial premises employ a plurality of apertured brass terminal blocks provided with retention screws which extend into each aperture at right angles to the direction in which the end of a conductor is inserted into the aperture. Thus a conductor may be secured in position by tightening the retention screw such that the screw bears against the conductor to hold the conductor firmly against the wall of the aperture.

Although the known connectors function satisfactorily they have the disadvantage that it can be time consuming to secure each conductor to the connector. Furthermore there is the risk that inadvertently a retention screw is not properly tightened, resulting in a poor electrical connection and risk of over-heating.

Another disadvantage of many known connectors is that they require the provision of a removable cover, for example to again access to terminal blocks such as those described above. That adds undesirably to the cost of the connector and also to the time needed to connect conductors to the connector.

Other constructions have been proposed but either result in a permanent connection, such as may be achieved by soldering, or render it difficult to allow release of a conductor.

To address at least some of the aforedescribed disadvantages of known connectors it has been taught in GB2525482A that a connector may be provided with resiliently biased limbs that engage with and serve to retain inserted conductors. Release of conductors is effected by inserting a small tool to deflect in turn each limb to allow withdrawal of the conductors. Although that construction performs well and provides good retention of a conductor, as well as security against inadvertent removal, for some applications it is preferable to be able more readily to remove one or more conductors.

The present invention seeks to provide an improved electrical connector in which at least some of the disadvantages of known connectors are mitigated or overcome, and which facilitates an improved ease of use.

In accordance with the present invention there is provided an electrical connector comprising a casing which defines at least one entry port through which at least one of a plurality of conductors may extend to within the casing, an interface formation supported by the casing to enable the connector to be connected to another connector, and a terminal formation within the casing to engage with an end region of at least one said conductor and provide electrical connection between said conductor and the interface formation, wherein said terminal formation comprises a resiliently biased retention limb having a distal end which, in use, bears against an inserted conductor to exert a bias force to urge the conductor to bear firmly against a confronting surface of the terminal formation and resist withdrawal of the conductor, said connector comprising a movable limb deflector which is operable from a position external of the casing and which extends to within the casing to bear against the resiliently biased retention limb whereby, in use, the deflector may be moved to cause the distal end of the resiliently biased limb to move away from the confronting surface of the terminal formation and thereby allow withdrawal or insertion of a conductor.

The term "conductor" is used herein to refer to an electrically conductive member and also to the combination of an electrically conductive member and a surrounding sheath of electrically non-conductive material.

The electrical connector may comprise a plurality of terminal positions.

The deflector may be supported by the casing.

The deflector may be formed integrally with the casing or may be secured to the casing. The deflector and casing may be formed from plastics material, for example by moulding. The deflector may comprise a flexible or otherwise depressible arm section having a first end associated with the casing and a second, distal end which is deflectable from a rest position by applying a force to the arm section.

The deflector preferably is of a unitary construction comprising a depressible arm section external of the casing and a formation that extends through the casing from the arm section to contact the resiliently biased limb. Alternatively the deflector may comprise two or more separate components.

The deflector may be in permanent contact with the resiliently biased retention limb or may contact the limb only when moved from a rest position.

The casing may comprise a barrier formation whereby during insertion of a conductor the end of the conductor is unable to reach a position at which the deflector contacts the resiliently biased limb thereby to extend over a part of the distal end of the limb, which will secure the conductor firmly against the confronting surface of the terminal formation.

The deflector may contact a resiliently biased limb at a position between the ends of the limb and in that case the distal ends of the limb may comprise a contact surface which extends across the full width of the limb for securing a conductor against the confronting surface of the terminal formation.

Alternatively a resiliently biased limb may comprise a distal end region having at least one first section that is adapted to engage with an inserted conductor to hold the conductor against the confronting surface of the terminal formation and a second section that is not adapted to engage with an inserted conductor.

If a barrier formation is provided, said second region may be substantially aligned with the barrier formation as considered in the direction of insertion of the conductor.

The distal end of a limb may comprise two said first sections adapted to engage with an inserted conductor and which are spaced apart by a said second section that is not adapted to engage with an inserted conductor. Thus two conductors may readily be secured in position by the single limb, each at a respective one of the two said first sections.

Two said distal end first sections may be associated with one another in a manner in which they will always move in unison. In an alternative construction one first section may be sufficiently deflectable independently of the other end to enable the limb to secure in position two conductors of different cross-sectional dimensions, but with the two first limb sections being movable in unison under the action of the deflector for the purpose of enabling removal of one or each of the conductors.

In an electrical connector in accordance with the present invention the or each terminal position may comprise a plurality of said obliquely extending and resiliently biased retention limbs (or limb sections) with the limbs being independently deflectable such that insertion of a conductor over one limb does not adversely deflect or adversely affect the bias force exerted by another limb at the same or any other terminal position. Accordingly following insertion of a conductor beneath one limb at a terminal position a second conductor of a greater thickness than the first conductor may be inserted over a second resiliently biased limb at the same terminal position without any significant risk of the first limb ceasing to exert a bias force sufficient to hold in place the first conductor.

The resiliently biased limb has been described above as comprising a distal end region having at least one said first section. In addition to the further feature to a distal end comprising two said first sections and a said second section, it is to be understood that the distal end may comprise three or more said first sections. Preferably each of at least two said first sections is spaced by a said second section that is not adapted to engage with an inserted conductor.

Two resiliently biased and individual limbs may be positioned alongside one another within a terminal formation and the distal end of each of the limbs may comprise a said first section and a said second section. The said second sections of the two limbs may be positioned alongside one another and may be movable in unison with one another under the action of a single deflector.

The resiliently biased limb may be formed from a flexible material such as spring steel, brass or other material which permits the limb to flex. Alternatively or additionally, however, the limb may be substantially inflexible and be secured, for example by a resiliently biased means, which may be a pivot, for example a spring loaded pivot, relative to the casing within which the terminal formation is located.

A resiliently biased limb may be part of a limb unit which comprises two sections which depend from an interconnecting fold region as an integral construction. One section may be the obliquely extending deflectable, resiliently biased retention limb and the other section may be adapted for securing substantially immovably relative to the terminal formation.

Although generally it will be sufficient to employ only the distal end of the obliquely extending retention limb to contact the conductor to bring the conductor into electrical contact with the interface formation, optionally an additional, auxiliary contact may be provided.

An auxiliary contact may be in the form of a resiliently biased limb which comprises an obliquely extending portion which is shaped to define a conductor-engaging zone that is positioned between end regions of the auxiliary contact. Said obliquely extending portion may comprise a distal end and in that case said distal end may lie at a position which, in use, is remote from the conductor. Said conductor engaging zone may lie spaced from said distal end.

Preferably the auxiliary contact is positioned closer to the interface formation than the obliquely extending, resiliently biased retention limb. Thus if there is a requirement to remove a conductor, that may be effected by depressing or otherwise deflecting the limb deflector.

The obliquely extending, resiliently biased limb and an auxiliary contact may be secured independently relative to the casing but more preferably are formed integrally with one another.

Preferably the auxiliary contact is formed from flexible material and is shaped to define at least two spaced apart bend regions. Two bend regions may have opposite directions of curvature.

A connector comprising an obliquely extending, resiliently biased limb and an auxiliary contact may comprise features described respectively in respect of first and second limbs in the specification of our patent specification GB 2525482A.

Preferably the auxiliary contact is substantially free to tend to deflect in a direction away from the conductor to bear less firmly against the conductor when a force is applied to withdraw the conductor. In contrast, due to the oblique orientation, the resiliently biased retention limb is inherently inhibited from tending to deflect in a direction away from the conductor when a force is applied to withdraw the conductor.

The obliquely extending resiliently biased limb may comprise a distal end which, in use, bears directly against and tends to indent into an inserted conductor. Thus any force applied to the conductor to tend to withdraw the conductor will tend to cause the limb to bear increasingly firmly against the conductor.

At least one of the resiliently biased limb and the confronting surface of the terminal formation may be of an electrically conductive material and in electrical contact with an interface formation. Preferably each of the resiliently biased limb and said confronting surface are electrically conductive and in electrical contact with the interface formation.

The interface formation may comprise at least one male formation such as an electrically conductive pin or at least one female formation such as an electrically conductive socket. The interface formation of a connector may comprise a combination of male and female formations.

The terminal formation may comprise a terminal housing which defines at least one cavity and the or each cavity may contain at least one resiliently biased limb and a terminal insert. The terminal insert may define that confronting surface of the terminal formation against which a conductor is urged to bear under the action of the bias force exerted by the resiliently biased limb.

The terminal insert may be substantially inflexible and have secured thereto at least one resiliently biased limb. The insert and limb may each be electrically conductive and in electrically conductive contact with one another. The limb may be in electrically conductive contact with an interface connection via the terminal insert.

In addition to comprising one or more terminal positions each associated with a respective interface formation, the electrical connector may comprise a terminal position which is not associated with an interface formation and which may be employed for example as a so-called loop connection terminal.

Preferably the entry port comprises at least one entry position comprising a resiliently biased cable or conductor grip of a type known per se. Thus a conductor may be secured relative to the connector casing and the end of the conductor may be secured to the terminal formation simply by an insertion action and without any requirement for operation of other retention means such as conventional terminal retention screws.

The entry port may engage with an electrically insulating sheath that directly surrounds a conductor, which may be a single or multi strand wire. Alternatively the entry port may engage with an outer sheath of a cable comprising at least one conductor within an insulating sheath.

To facilitate entry of a conductor into a terminal formation of the electrical connector the entry region of the terminal formation may comprise an aperture of a diameter which is substantially equal to that of the insulating sheath of a conductor with which the connector is intended to be used. The aperture may be a through bore of a length sufficient to tend to hold the conductor sheath aligned with the intended direction of insertion of the conductor. The bore preferable is a bore of a stepped diameter thereby to provide an abutment shoulder which prevents the sheath extending over the distal end of the obliquely extending, resiliently biased retention limb.

Optionally the entry region may comprise a guide formation, which may be a shelf like formation, at the entrance to the sheath-receiving bore thereby to further assist in alignment of the conductor with the longitudinal axis of the sheath-receiving bore. The guide formation may, for example, comprise a surface region of a semi cylindrical shape at the entrance to the bore. Thus correct positioning of the conductor within the terminal formation is further assisted.

One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:-Figure 1 is a perspective view of part of a connector in accordance with the present invention; Figure 2 is a plan view of the connector of Figure 1; Figure 3 is a plan view of the connector of Figure 1 together with an internal terminal cover; Figure 4 is a perspective view of a terminal part of the connector of Figures 1 to 3; Figure 5 is a perspective view of part of the terminal of Figure 4; Figure 6 is a perspective view of a terminal housing of the connector of Figure 1 to3; Figure 7 shows the housing of Figure 6 in a position to receive a conductor; Figure 8 is a perspective view of part of a terminal insert of the connector of Figure 1 to3; Figure 9 is a sectional side view of part of a terminal housing and inserted conductor, and Figure 10 is a perspective view of a retention spring for location at a loop terminal position.

An electrical connector (see Figures 1 to 3) comprises a casing in the form of a moulded plastics body 10 which is formed integrally with three entry ports 11, a terminal formation 12 comprising four terminals 13, 24 and three interface formation connections 14. Three 13 of the four terminals are each associated with a respective one of the interface formations and the fourth 24 is devoid of association with an interface formation.

The terminal formation additionally comprises a terminal housing 15 (see Figure 2) which for clarity is omitted from the view of Figure 1 but which is held in position in a click fit manner relative to the body 10 by means of deflectable abutments 16 as shown in Figure 1 and which engage with terminal formation abutments 16' (see Figure 6).

Each entry port 11 comprises a toothed reaction surface 20 and a toothed and resiliently biased arm 21 which deflects when a conductor is inserted between the reaction surface 20 and confronting surface 22 of the arm 21 in a manner in which the teeth bear against the conductor to resist outwards movement of the conductor from the connector.

The terminal housing 15 defines four cavities 17 each of which contains and supports a terminal 13, 24 comprising a terminal insert 18 (see Figure 4) and a resiliently biased retention member in the form of a spring 9 formed from spring steel.

The spring 9 (see Figures 4 and 5) of the terminals 13 comprises an integral formation of two arms, 25, 26 and a fold region 27 which lies between and interconnects the two arms. One arm 26 lies flat on a base section 28 of the terminal insert 18. The limb 26 is formed with an aperture 29 which locates with an upstanding formation 30 of the base 28 in order to locate the arm 26 relative to the insert 18 in the direction of the arrow X of Figure 4. The base 28 additionally comprises a pair of spaced apart and upstanding tabs 31 between which the arm 26 is located so as to prevent sideways movement in the direction of the arrow Y of Figure 4.

The other arm 25 functions as an obliquely extending, resiliently biased retention limb which extends obliquely relative to the arm 26 in a direction towards a confronting surface 33 of the terminal insert 18 and inherently tends to bear directly against that surface 33. The arm 25 is orientated to extend obliquely from the fold region 27 in a direction towards an end 34 of the insert 18, being the end at which an interface connection in the form of a socket 14 is secured to the insert 18.

The distal end 35 of the limb 25 comprises two spaced apart sections 36 (see Figure 5) of a square cut form and which in a rest position, in the absence of an interposed conductor, bear against the confronting surface 33 of the insert 18.

The two sections 36 are spaced apart by a section 37 that is turned downwards slightly from the plane of the main part of the limb 25 to extend in a direction towards the arm 26.

The section 37 serves as an abutment for contact by a deflector 40 (see Figures 6 to 9) operable from a position external of the casing body 10 to deflect the arm 25 towards the arm 26 and thus move the end sections 36 in a direction away from the terminal insert surface 33 such that a conductor present between one of the end sections 36 and the confronting surface 33 ceases to be held captive by the square cut end and may then be moved from the terminal. Similarly, that movement of the arm 25 allows deflection to a position at which a conductor may readily be inserted and, following release of a force applied by the deflector, then be held securely in position within the terminal housing.

The arm 25 is provided with a lengthwise extending slit 38 which extends between the distal end 35 and the fold region 27. In consequence the limb 25 comprises limb sections 25a and 25b (see Figure 4) which allow the two said end sections 36 respectively to firmly locate and retain conductors of different cross-sectional dimensions.

For the terminal 24 the spring 9 is of the modified kind shown in Figure 10 and which allows three conductors to be retained at a single terminal position. In this construction the limb 60 comprises two slits 61 whereby the limb is formed with three independently movable sections 60a, 60b, 60c for accommodating three conductors of different cross-sectional dimensions.

Each slit aligns with two halves 62 of a respective one of a pair of abutment surfaces 63 for movement simultaneously under the action of a deflector. Thus three conductors of different cross sectional dimensions may readily be inserted at the terminal position 24 or removed therefrom.

The deflector 40 (see Figure 6) comprises deflectable arm 41 which is moulded integrally with the terminal housing 15. The arm 41 comprises a depressible tab 42 from which an actuator leg 43 extends through an aperture 44 (see Figure 4) in the terminal insert 18. The deflector is inherently biased to reside in the position shown in Figure 6 but the tab 42 may be depressed manually to move the obliquely extending retention arm 25 downwards to a position shown in Figure 7 in order to facilitate ease of insertion of the conductor 50. Following release of the tab the conductor 50 is securely held in contact with the surface 33 of the insert 18 by the action of one of the square cut ends 36 of the retention limb 25.

In addition to supporting the deflector 40 the terminal formation 12 additionally defines two conductor insert positions 46 (see Figure 7) per terminal 13 and three conductor insert positions for the fourth, loop connector terminal 24.

Each terminal insert position 46 (see Figures 8 and 9) is in the form of a through bore of stepped diameter. A large diameter part of the bore is dimensioned to closely surround the insulation sheath 52 of the conductor 55 and the smaller diameter part is dimensioned to closely surround the electrically conductive core 50 of the conductor.

The shoulder 51 defined by the step in diameter of the bore acts as an abutment to inhibit entry of the conductor sheath 52 into the terminal to a position at which it might be engaged by the retention arm 25. The close fit of the sheath and conductor within the respective sections of the length of the through bore facilitate correct alignment of the conductor to a position at which it occupies the space between the arm 25 when depressed by the deflector 40 and the confronting surface 33 of the terminal insert. Additional support and guidance for the sheathed conductor is provided by the shelf like formation 49 comprising semi cylindrical supporting regions 55 providing one at each bore entry position 47.

Three of the terminal inserts 18 connect with a respective one of the three interface connectors 14 which are each contained within and supported by tubular extension formations 19 of the terminal housing. Each of the interface connectors 14 is shaped and positioned to engage with a complementary shaped interface formation of another connector (not shown).

In this embodiment of the invention as illustrated in Figures 1 to 3 each of the electrically conductive interface connectors 14 is in the form of a socket. Accordingly the complementary shaped interface formation of another connector for assembly with the illustrated connector typically is to comprise interface connectors in the form of electrically conductive pins which are a close sliding fit within the sockets 14.

A fourth terminal cavity contains a spring 9 and a terminal insert 18 which are devoid of any connection to an interface connector and may be utilized in known manner, such as a so-called loop terminal, to interconnect conductively two or more conductors.

An internal cover 38 extends over the terminals 12 and terminal housing 15 to assist in retaining the springs 9 within the respective terminal inserts 18.

In use, subsequent to positioning conductors to extend through the entry ports 11 and securing bared ends in the terminal springs 9, an outer cover (not shown) is click fitted to the connector body 10.

Although the invention has been described above in the context of an electrical connector comprising three entry ports, four terminals and three interface formations, it is to be understood that features of the invention as described above may be employed also, as appropriate, in the context of an electrical connector having two or four or more entry ports, two or four or more interface formations and fewer or more than four terminals. The number of terminals may equal the number of interface formations or may be greater so as to provide one or more auxiliary terminals such as a loop terminal. A terminal associated with an interface formation may comprise two conductor insert positions as described above or may comprise either a single or three or more conductor insert positions.

Claims

CLAIMS1. An electrical connector comprising a casing which defines at least one entry port through which at least one of a plurality of conductors may extend to within the casing, an interface formation supported by the casing to enable the connector to be connected to another connector, and a terminal formation within the casing to engage with an end region of at least one said conductor and provide electrical connection between said conductor and the interface formation, wherein said terminal formation comprises a resiliently biased retention limb having a distal end which, in use, bears against an inserted conductor to exert a bias force to urge the conductor to bear firmly against a confronting surface of the terminal formation and resist withdrawal of the conductor, said connector comprising a movable limb deflector which is operable from a position external of the casing and which extends to within the casing to bear against the resiliently biased retention limb whereby, in use, the deflector may be moved to cause the distal end of the resiliently biased limb to move away from the confronting surface of the terminal formation and thereby allow withdrawal or insertion of a conductor.
2. A connector according to claim 1 wherein the deflector is supported by the casing.
3. A connector according to claim 2 wherein the deflector is formed integrally with the casing.
4. A connector according to claim 2 or claim 3 and comprising a depressible arm section having a first end associated with the casing and a second, distal end which is deflectable from a rest position by applying a force to the arm section.
5. A connector according to any one of the preceding claims wherein the deflector is of a unitary construction comprising a depressible arm section external of the casing and a formation that extends through the casing to contact the resiliently biased limb.
6. A connector according to any one of the preceding claims wherein the deflector is in permanent contact with the resiliently biased retention limb.
7. A connector according to any one of the preceding claims 1 to 5 wherein the deflector contacts the resiliently biased retention limb only when moved from a rest position.
8. A connector according to any one of the preceding claims wherein the casing comprises a barrier formation positioned such that during insertion of a conductor the barrier formation ensures that the end of the conductor does not contact the resiliently biased limb at a position at which the deflector contacts the resiliently biased limb.
9 A connector according to any one of the preceding claims wherein the deflector contacts the resiliently biased limb at a position between the ends of the limb.
10. A connector according to any one of claims 1 to 8 wherein the resiliently biased limb comprises a distal end region having at least one first section adapted to engage with an inserted conductor to hold the conductor against the confronting surface of the terminal formation and a second section that is not adapted to engage with an inserted conductor.
11. A connector according to claim 10 wherein the deflector contacts the resiliently biased limb at said second section of the distal end region.
12. A connector according to claim 11 wherein the casing comprises a barrier formation positioned to guide a conductor away from a position at which the deflector contacts the resiliently biased limb and wherein the barrier formation is substantially aligned with said second section.
13. A connector according to any one of claims 10 to 12 wherein the distal end of a limb comprises two said first sections each adapted to engage with a respective inserted conductor and wherein said first sections are spaced apart by a said second section that is not adapted to engage with an inserted conductor.
14. A connector according to claim 13 wherein two said distal end first sections are associated with one another whereby they always move in unison.
15. A connector according to any one of claims 1 to 13 wherein the resiliently biased limb comprises two limb sections which are deflectable independently of one another to enable the limb to secure in position two conductors of different cross-sectional dimensions.
16. A connector according to claim 15 wherein the two limb sections are moveable in unison under the action of the deflector for the purpose of enabling the removal of one or each of the conductors.
17. A connector according to any one of the preceding claims wherein a terminal position comprises two resiliently biased and individual limbs movable in unison with one another under the action of a single deflector.
18. A connector according to any one of the preceding claims wherein a resiliently biased limb is part of a limb unit which comprises two sections which depend from an inter connecting fold region whereby the limb unit is of an integral construction.
19 A connector according to claim 18 wherein one said limb unit section is an obliquely extending deflectable resiliently biased retention limb and the other section is secured substantially immovably relative to the terminal formation.
20. A connector according to any one of the preceding claims wherein a terminal formation comprises said resiliently biased retention limb for contacting and retaining the conductor and an additional, auxiliary contact for contacting the conductor.
21. A connector according to claim 20 wherein said auxiliary contact comprises a resiliently biased limb comprising an obliquely extending portion which is shaped to define a conductor engaging zone positioned between end regions of the auxiliary contact.
22. A connector according to claim 21 wherein the obliquely extending, resiliently biased limb and auxiliary contact are formed integrally with one another.
23. A connector according to any one of the preceding claims wherein the terminal formation comprises a terminal housing which defines at least one cavity and said cavity contains at least one resiliently biased limb and a terminal insert.
24. A connector according to any one of the preceding claims wherein the terminal formation comprises an entry region and wherein said entry region defines an aperture of a diameter which is substantially equal to that of the insulating sheath of a conductor with which the connector is intended to be used.
25. A connector according to any one of the preceding claims wherein the terminal formation comprises an entry region which defines a through bore to receive a sheathed conductor and wherein a guide formation is provided at the entrance to the sheath receiving bore to assist alignment of the conductor with the longitudinal axis of the through bore..