GB2617410A

GB2617410A - Electrical connector

Info

Publication number: GB2617410A
Application number: GB2206939.7A
Authority: GB
Inventors: Turner Ross
Original assignee: Scolmore International Ltd
Current assignee: Scolmore International Ltd
Priority date: 2022-04-07
Filing date: 2022-05-12
Publication date: 2023-10-11
Also published as: GB202205080D0; GB202206939D0

Abstract

A two-pin socket (figure 1, 10) comprises two terminals 21 each suitable for receiving a respective pin of a two-pin plug (see figure 4). At least one of the said terminals 21 comprises a locking blade 30 inclined in a direction which facilitates deflection of the blade 30 as a pin is inserted, but which ensures that the blade 30 inherently tends to firmly engage with the pin when an attempt is made to withdraw the pin. The said locking blade 30 is formed from electrically non-conductive material. Each of the terminals 21 may comprise a locking blade 30. Each locking blade 30 may be formed from a ceramic material. The socket may comprise a release mechanism comprising two release components 17 31 each operable from a position external of a body (figure 1, 11) of the socket, and operable to engage with a locking blade 30 to allow separation of a plug from the socket.

Description

Electrical Connector This invention relates to an electrical connector such as may be employed for connecting between two items of electrical equipment or for connecting an item of electrical equipment to a power supply.

In this specification the term "socket" refers to an electrical connector comprising terminals into which the pins of another electrical connector may be inserted.

A problem which can arise in the use of electrical connectors is that typically they are prone to inadvertent disconnection. To address that there have been various proposals for reducing the ease with which the pins of a plug may be removed from a socket.

Some proposals for addressing the problem of unintended separation of a plug and socket require the use of screw fittings or clips but these commonly are found to be inconvenient in use, particularly for plug and socket combinations which need to be connected or separated from one another at relatively frequent intervals.

In respect of a socket for receiving a three-pin type plug having an earth pin it is described in EP 1459412 that the centrally positioned earth pin of the plug may be held captive by an inclined locking blade that engages with an inserted earth pin of a three-pin plug, in particular to engage with the smaller sized two faces of an earth pin of rectangular cross-section. Typically a release mechanism is provided and is operable to incline the blade in a direction away from the inserted pin.

The blade is inclined in a direction which facilitates deflection of the blade as a pin is inserted but which ensures that the blade inherently tends to firmly engage with the pin when an attempt is made to withdraw the pin unless a release mechanism has been operated to permit withdrawal.

Although a three-pin socket of the aforedescribed type functions very satisfactorily, it is not readily adaptable to provide sockets for receiving two-pin plugs and which are bereft of an earth pin. Notably, in consequence of the locking blade engaging with an earth pin instead of a pin at a high voltage, there are no potential problems that might otherwise occur such as arcing and radio frequency interference. Also any moisture ingress between the locking blade and a release mechanism does not pose the safety issue that potentially might arise if the locking blade engaged with a high voltage pin.

The present invention seeks to provide an electrical connector in the form of a two-pin socket comprising improved means for retaining in the socket the inserted pins of a two-pin plug.

In accordance with the present invention there is provided a two-pin socket comprising two terminals each for receiving a respective pin of a two-pin plug, at least one of said terminals comprising a locking blade inclined in a direction which facilitates deflection of the blade as a pin is inserted but which ensures that the blade inherently tends to firmly engage with the pin when an attempt is made to withdraw the pin, and wherein said locking blade is formed from electrically non-conductive material.

Two terminals may be provided with a locking blade of electrically nonconductive material whereby withdrawal of each pin is resisted by a locking blade.

The socket may comprise two individual locking blades each for engagement with a respective pin of an inserted two-pin plug or the socket may comprise a single locking blade for engaging each of the two pins of an inserted two-pin plug.

In a preferred embodiment the or each blade is formed from a ceramic material.

The ceramic material preferably has a hardness in the range HV700 to 1000, more preferably in the range HV800 to 900.

The or each locking blade preferably has a thickness of at least 0.5mm, more preferably at least lmm.

Preferably the or each locking blade makes an angle of between 600 and 850 relative to the length of an inserted pin, and thus relative to the direction of insertion of a pin, more preferably in the range 65° to 80°.

Although for some applications there is a requirement for a socket permanently to retain an inserted plug, more commonly there is a requirement to permit intended separation of a plug from a socket. To address that requirement the present invention teaches that the socket may comprise a release mechanism.

The release mechanism may comprise a release component which is operable from a position external of the body of the socket to effect simultaneous movement of two locking blades to allow withdrawal of the two pins of a plug.

The release mechanism may comprise two release components each operable from a position external of the body of the socket and each operable to engage with the or each locking blade to allow withdrawal of the pins. The two release components may be movable in opposite directions relative to the body of the socket such that if located at opposite positions of the socket body they may readily be depressed simultaneously thereby to move towards each other and thereby, for example, facilitate simultaneous disengagement of the locking blade(s) from firm contact with each pin of an inserted plug.

Preferably the locking blade defines an aperture through which a pin may be inserted and wherein at least a part of the edge of the locking blade that defines said aperture is able to engage with an inserted pin to retain the pin from withdrawal from the terminal.

Preferably the dimensions of the aperture in the locking blade are substantially the same as those of a cross-section of a portion of the pin. Accordingly, if the blade is substantially perpendicular to the direction of insertion of the pin, the pin may be freely inserted but, when the blade is angled with respect to the direction of insertion of the pin, the blade seizes the pin if there is an attempt to withdraw the pin prior to operation of the release mechanism.

Preferably the locking blade is biased, preferably resiliently, towards an angled position at which it inherently tends to resist removal of the pin from the terminal.

Preferably at least a part of the edge of the aperture in the locking blade engages and retains an inserted pin by frictional forces. Preferably a front face of the locking blade has a first angular edge at one side of the aperture and a rear face of the blade has a second edge at a position of aperture opposite that of the first angular edge, the first and second edges being arranged to bite into the pin when the blade is angled.

It is not essential that the locking blade is provided with an aperture through which a pin may be inserted. Although advantageously the aperture may be dimensioned two positions of an inserted pin, alternatively an edge region of the periphery of the locking blade may be employed to engage with a single position of an inserted pin, The axis about which a locking blade changes in angle of inclination when moved to a release position may extend in a direction perpendicular to a plane containing two terminals that are positioned parallel with one another within the body of the connector.

Alternatively the axis about which a locking blade may change in angle of inclination when moved to a release position may be parallel with a plane containing two terminals that extend parallel with one another. In this alternative a single locking blade may be employed to engage with either one or two of the pins of an inserted two-pin plug or two locking blades may be provided each to engage with a respective one of the pins of an inserted two-pin plug.

The socket may be adapted for use in connecting with a two-pin plug that is in accordance with the NEMA standards. Accordingly each terminal may be adapted to receive a pin of rectangular cross section and comprising a pair of faces larger than the other two faces. If the plug comprises two pins of rectangular cross-section orientated such that a larger face of one pin confronts the larger face of the other pin, the locking blade may be arranged to engage with at least one of the smaller faces of an inserted pin. However preferably, in order to provide a more compact construction, the locking blade is arranged to engage with a larger face of an inserted pin.

Embodiments of the present invention will now be described by way of example only, with reference to the accompanying diagrammatic drawings in which:-Figure 1 is a perspective view of a socket type connector in accordance with one embodiment of the present invention; Figure 2a is a perspective view of the socket of Figure 1 with part of the connector housing removed, Figure 2b is a plan view of part of the connector of Figure 2a; Figure 2c is a perspective view of a locking place; Figure 3a corresponds to Figure 2a but shows the locking blade positioned to allow withdrawal of an inserted pin; Figure 3b is a plan view of part of the connector as shown in Figure 3a; Figure 4 is a longitudinal sectional view of an assembly of the socket of the aforementioned Figures and a two-pin plug, and Figure 5 is a view corresponding substantially to that of Figure 2 but illustrates a socket in accordance with a second embodiment and having a locking blade for engagement with only one of the pair of pins of a two-pin plug.

A connector in the form of a two-pin socket 10 (see Figure 1) comprises a body in the form of a housing 11 of electrically non-conductive material such as a plastics material.

The housing 11 comprises an upper housing portion 12 and a lower housing portion 13.

The lower housing portion comprises a grooved periphery 14 (see Figure 2) which receives a lip portion (not shown) of a confronting surface of the upper housing portion 12 thereby to enable the two housing portions to be located relative to one another. The two housing portions may be secured together in a known manner such as by means of screws or may be permanently secured together for example by means of a click flit, by means of adhesives or heat welding.

The housing 11 provides support for a flexible cable entry sleeve 16 and also a release handle 17 which is slidably secured about the outside of the housing for movement in a direction parallel with the length of the housing.

The housing portions 12, 13 define a front face 18 comprising two openings 19, 20 each for receiving a respective pin of a two-pin plug. In this embodiment the openings are orientated to receive two pins of rectangular cross-section orientated such that a larger face of one pin confronts the larger face of the other pin.

The socket is intended for use in connecting with a two-pin plug that is in accordance with the NEMA standards and accordingly each of the openings 19, 20 is of a rectangular shape.

Located within the housing are two elongate terminals 21 (see Figures 2a, 2b and 4) each comprising a pair of flexible electrically conductive arms 22, 23 each open at a flared end 24 aligned with the openings 19, 20 in the front face. The arms 22, 23 are inter-connected at the other end 25 of the terminal and said other end 25 is provided with connection means known per se, for example a crimpable formation 26 to locate with a conductor (not shown) that extends into the body through the flexible cable entry sleeve 16.

The housing also provides location for a pair of locking blades 30 and parts of the release mechanism. Each blade is formed with a rectangular aperture 29 which comprises two longer edges 28 that, as described below, in use each engage with the larger side faces of an inserted pin of rectangular cross-section.

The release mechanism comprises a resiliently biased actuator 31 of electrically non-conductive material.

One end of the actuator is formed with a pair of notches 32 for receiving and locating an edge 38 of a locking blade 30. A compression spring 33 is secured at one end to the housing and the other end resiliently biases the actuator 31 towards the front face 18 of the housing.

The actuator is formed integrally with a protrusion 34 that extends through a slot (not shown) in the upper housing portion. The protrusion 34 locates in a slot 35 defined by the slidable handle 17 such that movement of the handle in a direction away from the housing front face 18 results in movement of the actuator and the associated locking blade edges 38 in a direction away from the front face.

The locking blade (see Figures 2b and 2c) is of a rectangular shape and an edge of the blade opposite the edge 38 is located in a fixed notch 39 defined by the upper and lower housing portions.

Accordingly under the biasing action of the spring 33 the locking blades are initially inclined relative to the front face in the manner shown in Figure 2b and thus also inclined relative to the length direction of each terminal. However as the external handle 17 is slid away from the front face 18 the actuator similarly moves away from the front face thereby to result in tilting of the locking blade to lie in a plane aligned with the front face of the housing as best seen in Figures 3a and 3b. That is, the locking blades are tilted about axes that extend in a direction perpendicular to the plane of that edge of the lower housing portion that engages with the confronting edge surface of the upper housing portion.

In use the biasing action provided by the spring ensures that the locking blades inherently tend to reside in the inclined position as shown in Figure 2a and 2b. In that position the blades present an initial resistance to insertion of the pins of a two-pin plug but subsequently the locking blades deflect against the biased force exerted by the compression spring until the locking blades present an opening to the front of each locking pin sufficient to allow entry of the locking pins into the terminals.

Following insertion of the pins into the terminals the biasing force provided by the compression spring results in the opposite edges of the locking blade opening engaging with the pins as shown in Figure 4 and there results an inherent tendency for those edges to frictionally engage with and bite into each pin in the event of any attempt at unintended separation of the plug and socket.

However to effect separation of the plug and socket the handle is moved in a rearwards direction away from the front face of the housing thereby to reduce the angle of inclination of each locking blade such that the plug pins may then by freely withdrawn.

It is not essential that two locking blades are provided. In a further embodiment of the invention (see Figure 5) only a single locking blade 50 is provided. That will not provide the balanced resistance to separation as provided in the case of two locking blades or resistance to forced separation but may be sufficient in some applications.

Claims

Claims 1. A two-pin socket comprising two terminals each for receiving a respective pin of a two-pin plug, at least one of said terminals comprises a locking blade inclined in a direction which facilitates deflection of the blade as a pin is inserted but which ensures that the blade inherently tends to firmly engage with the pin when an attempt is made to withdraw the pin, and wherein said locking blade is formed from electrically non-conductive material.
2. A socket according to claim 1 wherein each of the two terminals comprises a locking blade.
3. A socket according to claim 1 or claim 2 comprising two locking blades each for engagement with a respective pin of an inserted two pin plug.
4. A socket according to claim 1 and comprising a single locking blade for engaging with each of the two pins of an inserted two pin plug.
5. A socket according to any one of the preceding claims wherein the or each blade is formed from a ceramic material.
6. A socket according to claim 5 wherein the ceramic material has a hardness in the range HV700 to 1000.
7. A socket according to claim 5 wherein the ceramic material has a hardness in the range HV800 to 900.
8. A socket according to any one of the preceding claims wherein the locking blade has a thickness of at least 0.5mm.
9. A socket according to claim 8 wherein the locking blade has a thickness of at least 1.0mm.
10. A socket according to any one of the preceding claims wherein the or each locking blade makes an angle of between 600 and 850 relative to the length of an inserted pin.
11. A socket according to any one of the preceding claims and comprising a release mechanism operable to permit separation of a plug from the socket.
12. A socket according to claim 11 and comprising a release component which is operable from a position externally from a body of the socket to effect simultaneous movement of two locking blades to allow separation of a plug from the socket.
13. A socket according to any one of claim 1 to 11 wherein the socket comprises a release mechanism comprising two release components each operable from a position external of a body of the socket and operable to engage with a locking blade to allow separation of a plug from the socket.
14. A socket according to claim 13 wherein the two release components are movable in opposite directions relative to a body of the socket whereby they may be depressed simultaneously towards each other to permit withdrawal of a plug from the socket.
15. A socket according to any one of the preceding claims wherein the locking blade is biased towards an angled position at which it inherently resists removal of the pin of a plug from the terminal.
16. A socket according to claim 15 wherein the locking blade is resiliently biased towards said angled position.
17. A socket according to any one of the preceding claims wherein the or each locking blade defines an aperture through which a pin may be inserted and wherein, in use, at least a part of the edge of the locking blade that defines said aperture is able to engage with an inserted pin to retain the pin from withdrawal from the terminal
18. A socket according to claim 17 wherein at least a part of the edge of the aperture in the or each locking blade engages and retains an inserted pin by frictional force.
19. A socket according to any one of the preceding claims wherein the axis about which a locking blade changes in angle of inclination when moved to a release position extends in a direction perpendicular to a plane containing two terminals that are positioned parallel with one another within the body of the connector.
20. A socket according to any one of claims 1 to 18 wherein the axis about which a locking blade changes in angle of inclination when moved to a release position is parallel with a plane containing two terminals that extend parallel with one another within the body of the connector.
21. A socket according to any one of the preceding claims where each terminal is adapted to receive a pin of rectangular cross-section.
22. A socket according to claim 21 and wherein the terminals are adapted to receive two pins of rectangular cross section orientated such that a larger face of one pin confronts the larger face of the other pin and a locking blade is arranged to engage with least one of the smaller faces of an inserted pin.
23. A socket according to any one of claims 1 to 21 wherein the terminals are adapted to receive two pins of rectangular cross section orientated such that a larger face of one pin confronts the larger face of the other pin and a locking blade is arranged to engage with least one of the larger faces of an inserted pin.