GB2209633A

GB2209633A - Shuttered electrical connectors

Info

Publication number: GB2209633A
Application number: GB8721070A
Authority: GB
Inventors: Malcolm James Wootton; John Crawshaw Taylor
Original assignee: Strix Ltd
Current assignee: Strix Ltd
Priority date: 1987-09-08
Filing date: 1987-09-08
Publication date: 1989-05-17
Also published as: GB8721070D0

Abstract

A shutter 18, biassed to cover socket contacts 12 beneath openings 16 in the body 8 of a connector 7 is moved against the bias to uncover the openings 16, when a counterpart 1 is mated with the connector, by contact with a part of the counterpart 1 other than its contact pins 3. The shutter 18 includes pins (not shown) running in slots 21 in the connector body 8 and a toothed edge 19 corresponding to a toothed region 16 of the connector. <IMAGE>

Description

ELECTRICAL CONNECTORS This invention relates to electrical connectors.

Electrical connectors are well known which include a female socket connector adapted for engagement with a complementary male terminal pin connector, the pin connector often including a shroud which at least partly surrounds the pins and which defines a recess whose cross-section corresponds approximately to the cross-section of the socket connector.

The shroud serves the dual purpose of protecting the pins and providing guidance for the socket connector as it is engaged with and disengaged from the pins. Such connectors are commonly associated with electrical appliances such as electric kettles, hot water jugs, urns, coffee percolators, electric irons etc., in which case the male pin connector traditionally is mounted to the appliance with the shroud often being defined by an external part of the appliance, and the female socket connector is connected or connectable to the mains for the supply of electric power to the appliance when the socket connector is inter-engaged with the pin connector.

It is important for safety reasons that access may not be readily gained to live parts of a socket connector. In wall-mounted type socket connectors the electrical contacts of the connector are commonly mounted within an insulated housing behind a shutter mechanism adapted to be opened only upon engagement with the pins of a complementary male pin connector.

In a typical such arrangement the socket connector includes apertures at its front end for receiving the respective free ends of the male pins, with a shutter member or members of the shutter mechanism being recessed with respect to the apertures and being laterally movable against a spring restoring force in response to camming action thereon by the pins so as to provide access for the pins to engage respective electrical contacts mounted behind the shutter mechanism. Such an arrangement provides adequate safety in many applications.

There has recently been proposed a new breed of electrical appliances, namely "cordless" appliances wherein the appliance is supplied together with a corresponding free standing base unit defining a receiving area for a lower part of the appliance, the socket connector forming part of the base unit.

In such an arrangement the terminal pins of the male pin connector are arranged vertically on the underside of the appliance for engagement with the socket connector when the appliance is engaged with its base unit; it is therefore the base unit rather than the appliance which is seen to be electrically connected to the mains via an electric lead. The most common form of cordless electrical appliances are presently continental style hot water jugs, although the principle is applicable to other electrical appliances such as irons. Examples of cordless appliances are described in our copending UR patent application no. 8717626.

In addition to preventing access to the live parts it is also important that the arrangement of the female socket connector is such that water is prevented in normal use from impinging on the live parts with the consequent risk of arcing or short circuiting. This problem is of potentially greater significance in the case of a cordless electric jug of the type described above in which the socket connector is mounted to a base unit and is arranged for engagement with the pin connector by vertical movement of the latter. In known socket connectors apertures for receiving the respective pins are therefore upwardly facing in a cordless arrangement and define upwardly facing recesses; such recesses form water traps which tend to collect any water which is inadvertently spilled onto the base unit in the region of the socket connector.

Known forms of shutter mechanism normally associated with wall mounted connectors if mounted behind the pin receiving apertures might when closed initially prevent water so trapped from impinging an electrical parts of the connector, but as soon as the shutter mechanism is opened the water would be released into the internal parts of the connector. Moreover the cam surfaces normally associated with the shutter member or members and arranged for engagement with the ends of the terminal pins would themselves define further recesses constituting additional potential water traps.

Viewed from one aspect the invention provides an electrical connector comprising a male terminal pin connector adapted for engagement with a female socket connector, the socket connector including a shutter member which is resiliently biased into a closed condition for shielding electrical contacts of the socket connector when disengaged from the pin connector, the shutter member being movable to an open condition when the pin and socket connectors are interengaged whereby the terminal pins have access for engagement with said electrical contacts, such shutter member movement being caused by cooperation of the shutter member with a part of or associated with the male pin connector which part is separate from the terminal pins of the connector.

In accordance with the invention a shutter member is therefore provided to prevent water impinging on the electrical contacts of the socket connector when disengaged from the pin connector without the need for the shutter to be opened by a camming action thereon by the terminal pins. This means that in practice apertures providing guidance for the respective pins in front of the shutter member may be avoided as may further recesses defined by cam surfaces in the region engaged by the pins formed on the shutter member itself. The shutter may thus present a substantially flat or slightly convex surface which confronts the male connector until such time as the shutter is opened by cooperation thereof with a part of the pin connector which is separate from the pins.The problem with the prior art connectors of water collecting in recesses associated with the upper face of the socket connector when orientated vertically on the base unit of a cordless appliance such as a cordless hot water jug may therefore be avoided.

A further advantage of a connector in accordance with the invention is that since the terminal pins are not required to apply a camming force to open the shutter, the thickness of the pins and thus the size of apertures provided, in a preferred embodiment, behind the shutter member, through which apertures the pins extend for engagement with the electrical contacts of the socket connector, may be reduced as compared with known connectors.

This reduces the possibility of e.g. a child gaining access to live parts of the control with an elongate member such as a screw-driver.

In a preferred embodiment the movable shutter member defines part of the front face of the socket connector i.e. the upper face when the connector is vertically orientated in the base unit of a cordless appliance. Preferably, the front face of the connector is substantially flat, or defines a generally curved or convex shape, when the shutter member is in its closed condition so that the possibility of any water collecting on the front face is avoided.

In a preferred embodiment, respective pin receiving apertures are located behind the shutter member which communicate with respective chambers of the socket connector housing electrical contacts arranged for engagement with respective terminal pins of the pin connector. It is preferred that such chambers are substantially sealed or shielded from one another, thus further reducing the possibility of short-circuits being formed between the contacts due to water collecting in the socket connector.

It will be appreciated that the provision of sealed contact chambers is made possible in the preferred embodiment by the fact that the shutter member is mounted in front of the apertures providing access into the chambers for the respective male connector pins. The arrangement of an internal shutter mechanism in accordance with most prior art connectors precludes the possibility of the contacts being located in respective sealed chambers.

Such an arrangement is advantageous in its own right, and accordingly viewed from a further aspect the invention provides'a female socket connector wherein electrical contacts of the connector are located in respective chambers substantially sealed or shielded from one another, apertures being provided in a front wall of said chambers through which respective terminal pins of an associated male pin connector can extend for engagement with the respective contacts, there being a shutter member mounted in front of said apertures for shielding said apertures when the socket and pin connectors are disengaged, the shutter member being movable to provide access to said apertures for the terminal pins of a male connector when engaged with the socket connector.

A preferred configuration for the shutter member is that it includes a generally saw-tooth shaped edge which engages with a complementary fixed saw-toothed member when the shutter is in its closed condition. In this case apertures providing access to the respective contact members as aforesaid are preferably provided between the teeth of the fixed saw-toothed member.

In a preferred such embodiment the complementary teeth of the shutter member and fixed member define angled engagement surfaces so that the opening and closing movement of the shutter member is in an oblique direction with respect to the planes in which the male terminal pins lie when a pin connector is engaged with the socket connector.

The travel of the shutter member may conveniently be provided by a travelling pin in slot connection between the shutter member and an underlying fixed part of the socket connector; advantageously pins projecting downwardly from the shutter member are slidingly engaged in slots formed in the underlying part of the socket connector.

In a preferred embodiment the shutter member is resiliently biased into its closed condition by means of a spring. In one embodiment the spring constitutes a wire spring which during assembly of the socket connector is mounted after the shutter member has been located by virtue of a pin in slot connection as aforesaid, the spring also acting to maintain the shutter member in place.

Whilst it is envisaged that in accordance with the first aspect of the invention, a part of or associated with the male pin connector which cooperates with the shutter member to open the same may vary and for example might constitute a cam member specifically provided for that purpose, in a particularly preferred embodiment the male connector includes a shroud which at least partly surrounds the terminal pins and which defines a recess providing guidance for the socket connector, the shroud cooperating with the shutter member to open the shutter member when the socket and pin connectors are interengaged. The shroud may thus define a cam surface on one side thereof which cooperates with a cam following surface formed on the shutter member to move the shutter member against the resilient biasing force.It will be appreciated that the shroud provides guidance for the socket connector so that it is appropriately initially aligned with the terminal pins, which is important in the preferred embodiment discussed above in which the shutter member defines part of a flat front face of the socket connector so that there are no recesses to provide initial guidance for the pins.

As mentioned above, an electrical connector in accordance with the invention is particularly suitable for use in conjunction with a "cordless" electrical appliance, and viewed from a further aspect the invention provides such an appliance and base unit therefor incorporating an electrical connector as aforesaid, wherein the terminal pins of the male connector are arranged vertically in a lower part of the appliance and the socket connector is mounted to the base unit. In such an arrangement a shroud surrounding the terminal pins may form part of e.g. a cover member of the appliance itself or may constitute a separate member mountable to the appliance adjacent the pins.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein: Figure 1 is an exploded view in cross-section illustrating a male terminal pin connector and a female socket connector in accordance with the invention; Figure 2 is a vertical cross-section illustrating the male pin and socket connectors inter-engaged with one another; Figure 3 is a section along the line III III in Figure 2 illustrating the housing of the socket connector, with the male pin connector and the shutter member removed; Figure 4 is a generally schematic view illustrating the underside of the top wall of the housing and showing the spring mounting of the shutter member; Figure 5 is a section along line V-V of Figure 4;; Figures 6a and 6b are schematic top plan views illustrating the shutter member in its closed and open conditions; and Figures 7a to 7c are sectional views along line VII-VII of Figure 6a illustrating displacement of the shutter member by the male pin connector shroud.

Referring to Figure 1 the parts of an electrical connector in accordance with the invention are shown exploded for reasons of clarity. The connector includes a male terminal pin connector 1 comprising a shroud 2 of plastics material surrounding downwardly projecting terminal pins 3. The male connector may be mounted e.g. to the base of a so-called cordless jug by means of a fixing bolt 4. As described in our co-pending patent application No. 8717626 the terminal pins are provided with sleeves 5 for engagement over horizontally disposed terminal pins 6 forming part of a thermally-sensitive control unit of the jug whereby the pins 3 are electrically connected via switch means of the control unit to the heater of the jug.

A female socket connector 7 includes a housing 8 whose cross-section corresponds to the recess defined by the male pin connector shroud 2 whereby the shroud engages over the housing 8 and provides guidance for the inter-engagement between the male and female connectors. The housing 8 includes longitudinally extending dividing walls 9 (Figure 3) which define respective substantially sealed chambers 10 of the housing when it is mounted on an underlying base surface (not shown). Located in each of the chambers 10 is a leaf spring contact 11 provided at its free end with a contact member 12 for engagement with a respective pin 3 of the male pin connector 1, as will be described further below.The ends of the contacts 11 remote from the contact members 12 are provided with connectors 13 whereby the contacts 11 may be readily connected to a cable for the supply of mains power to the connector.

Apertures 15 provided in the top wall of the housing 8 communicate with respective ones of the chambers 10 and provide access for the terminal pins 3 of the male connector into the chambers for engagement with the contact members 12 when the connectors 1,7 are inter-engaged. As shown in Figures 1 and 6b the apertures 15 are located between the teeth 16 of a fixed saw tooth member which is formed integrally with the top wall of the housing 8.

A shutter member 18 including a complementary saw toothed edge 19 is mounted for sliding movement between a closed position shown in Figure 6a wherein the apertures 15 are covered, and an open condition shown in Figure 6b wherein the apertures 15 are exposed for engagement by the male pins 3.

The shutter member 18 is mounted by means of pins 20 projecting downwardly therefrom which engage in angled slots 21 formed in the top wall of the housing. The outer ones of the pins 20 include lateral flanges 22 which engage under the top wall of the housing so as to prevent the shutter member being lifted from the housing. During assembly such flanges are inserted through complementary slots 22 formed at the front ends of the respective slots 21, and after the shutter member has been thus engaged a spring 23 is engaged around the central pin 20 which is not provided with a flange 22. In this way it will be seen that the spring 23 serves the dual purpose of resiliently biasing the shutter member 18 into its closed condition and maintaining the shutter member in place.As shown in Figure 5 additional guidance for the shutter member may be provided by ridges 24 provided in the top wall of the housing 8 which engage in grooves 25 formed in the shutter member 18.

As shown in Figures 6a, 6b, 7a-7c, the housing 8 includes a recess 26 on one side thereof defining an overhanging part of the shutter member 18 in its closed condition having an angled cam following surface 27 formed on the edge thereof. The corresponding side wall 28 of the male pin connector shroud 2 is formed with a complementary cam surface 29 so that, as shown in Figures 7b and 7c, when the shroud is engaged over the housing 8 the shutter member 18 is moved to its open condition by engagement with the shroud, so that the apertures 15 are exposed for engagement by the pins 3. As shown in Figure 2 the shroud 2 extends somewhat below the ends of the pins 3 so that initial alignment of the male and female connectors is achieved and the shutter is opened before the pins engage the apertures 15.

The top surface of the socket connector defined by the shutter member 18 and fixed saw toothed member 17 in the closed condition of the shutter member is generally flat, or may in an alternative embodiment be slightly domed or convex shaped.

In this way water does not collect on the upper surface of the connector when the shutter member is closed. As shown in Figures 6a and 6b the direction of travel of the shutter member 18 is at an oblique angle (defined by the slots 21 and the angle edges of the saw teeth 16) with respect to the longitudinal planes in which the male pins 3 and slots 15 lie.

This arrangement is advantageous to the extent that the length of travel of the shutter member 18 is reduced as compared with movement of the shutter in a direction parallel to the longitudinal planes of the pins, whilst no gaps need be defined between the saw teeth of the fixed and shutter members 17,18 in the closed condition, as would need to be the case if the direction of travel of the shutter member was perpendicular to the longitudinal planes of the pins.

As mentioned above since the terminal pins 3 do not effect by caming action the movement of the shutter member 18 against the spring biasing force the thickness of the terminal pins and thus the size of the apertures 15 may be reduced as compared with electrical connectors provided with known shutter mechanisms. Thus, whilst it is possible for someone manually to move the shutter member 18 into its open condition without engaging a male connector therewith, the size of the exposed apertures 15 and the spacing thereof from the contact members 12 is such that access to the contact members is so limited that the preferred connector meets British Standard safety requirements.

As mentioned above the male pin connector may be mounted to the base of a so-called cordless jug, and in this case the socket connector 7 is mounted to the base unit of the jug so that the connectors are interengaged when the jug is placed on its base unit.

Claims

CLAIMS:

1. An electrical connector comprising a male terminal pin connector adapted for engagement with a female socket connector, the socket connector including a shutter member which is resiliently biased into a closed condition for shielding electrical contacts of the socket connector when disengaged from the pin connector, the shutter member being movable to an open condition when the pin and socket connectors are inter engaged whereby the terminal pins have access for engagement with said electrical contacts, such shutter member movement being caused by cooperation of the shutter member with a part of or associated with the male pin connector which part is separate from the terminal pins of the connector.

2. A connector according to claim 1 wherein the movable shutter member defines part of the front face of the socket connector.

3. A connector according to claim 2 wherein the front face of the socket connector is substantially flat when in its closed condition.

4. A connector according to claim 2 wherein the front face of the socket connector is generally domed or convex when in its closed condition.

5. A connector according to any preceding claim wherein respective pin receiving apertures are located behind the shutter member which communicate with respective chambers of the socket connector housing electrical contacts arranged for engagement with respective terminal pins of-the pin connector.

6. A connector according to claim 5 wherein said chambers are substantially sealed or shielded from one another.

7. A connector according to any preceding claim wherein the shutter member includes a generally saw-tooth shaped edge which engages with a complementary fixed saw-toothed member when the shutter is in its closed condition.

8. A connector according to claim 7 wherein the complementary teeth of the shutter member and fixed member define angled engagement surfaces so that the opening and closing movement of the shutter member is in an oblique direction with respect to the planes in which the male terminal pins lie when a pin connector is engaged with the socket connector.

9. A connector according to any preceding claim wherein the travel of the shutter member is provided by a travelling pin in slot connection between the shutter member and an underlying fixed part of the socket connector.

10. A connector according to claim 9 wherein pins projecting downwardly from the shutter member are slidingly engaged in slots formed in the underlying part of the socket connector.

11. A connector according to any preceding claim wherein the shutter member is resiliently biased into its closed condition by means of a spring.

12. A connector according to claim 11 wherein the spring comprises a wire spring.

13. A connector according to any preceding claim wherein the male connector includes a shroud which at least partly surrounds the terminal pins and which defines a recess providing guidance for the socket connector, the shroud cooperating with the shutter member to open the shutter member when the socket and pin connectors are interengaged.

14. A female socket connector wherein electrical contacts of the connector are located in respective chambers substantially sealed or shielded from one another, apertures being provided in a front wall of said chambers through which respective terminal pins of an associated male pin connector can extend for engagement with the respective contacts, there being a shutter member mounted in front of said apertures for shielding said apertures when the socket and pin connectors are disengaged, the shutter member being movable to provide access to said apertures for the terminal pins of a male connector when engaged with the socket connector.

15. A connector according to claim 14 wherein the movable shutter member defines part of the front face of the socket connector.

16. A connector according to claim 15 wherein the front face of the socket connector is substantially flat when in its closed condition.

17. A connector according to claim 15 wherein the front face of the socket connector is generally domed or convex when in its closed condition.

18. A connector according to any of claims 14 to 17 wherein the shutter member includes a generally saw-tooth shaped edge which engages with a complementary fixed saw-toothed member when the shutter is in its closed condition.

19. A connector according to claim 18 wherein the complementary teeth of the shutter member and fixed member define angled engagement surfaces so that the opening and closing movement of the shutter member is in an oblique direction with respect to the planes in which the male terminal pins lie when a pin connector is engaged with the socket connector.

20. A connector according any of claims 14 to 19 wherein the travel of the shutter member is provided by a travelling pin in slot connection between the shutter member and an underlying fixed part of the socket connector.

21. A connector according to claim 20 wherein pins projecting downwardly from the shutter member are slidingly engaged in slots formed in the underlying part of the socket connector.

22. A connector according to any of claims 14 to 21 wherein the shutter member is resiliently biased into its closed condition by means of a spring.

23. A connector according to claim 22 wherein the spring is a wire spring.

24. A connector according to any of claims 14 to 23 wherein the male connector includes a shroud which at least partly surrounds the terminal pins and which defines a recess providing guidance for the socket connector, the shroud cooperating with the shutter member to open the shutter member when the socket and pin connectors are interengaged.

25. An electrical connector substantially as hereinbefore described with reference to the accompanying drawings.

26. An electrical appliance and a base unit therefor incorporating a connector according to any preceding claim.

27. An appliance according to claim 26 wherein the terminal pins of the male connector are arranged vertically in a lower part of the appliance and the socket connector is mounted to the base unit.