GB2388256A

GB2388256A - Improvements relating to cordless electrical appliances

Info

Publication number: GB2388256A
Application number: GB0209903A
Authority: GB
Inventors: Robert Andrew O'neill
Original assignee: Otter Controls Ltd
Current assignee: Otter Controls Ltd
Priority date: 2002-04-30
Filing date: 2002-04-30
Publication date: 2003-11-05
Anticipated expiration: 2022-04-30
Also published as: GB2388256B; EP1500171A1; WO2003094307A1; GB0209903D0; CN1650484A; AU2003222967A1

Abstract

Cordless electrical appliances, kettles and hot water jugs in particular, are known which have 360{ connector sets incorporating spring contacts which have to be carefully designed. To avoid this necessity, the invention proposes a 360{ connector set consisting of a plug part [12] having three triangularly arranged pin terminals [11] and a socket part [1] having three complementary coaxial terminals, [2,3,4] the plug and socket terminals all being fixed components. The socket part [1] is resiliently mounted in the base unit [14] of the cordless appliance so as to be able to adjust its position to accommodate tolerance variations and/or misalignments between the two parts of the connector set.

Description

IMPROVEMENTS RELATING TO CORDLESS

ELECTRICAL APPLIANCES

Field of the Invention:

5 This invention concerns improvements relating to cordless (as opposed to corded) appliances wherein electricity is provided to the appliance proper through a corded base unit (otherwise known as a power base) upon which the appliance proper may be removably seated so as to cause complementary electrical connectors that are provided in the appliance proper 10 and in the base unit to interengage for supplying electricity through the base unit to the appliance proper. In the following, the invention will be described by reference to cordless liquid heating appliances, particularly though not exclusively water heating appliances such as kettles and hot water jugs for example, but it is to be understood that the invention has wider application.

15 Background of the Invention:

Cordless electric kettles and hot water jugs are well known. Such appliances originally had their complementary electrical connectors so configured that the appliance proper could be set down onto its base only in a particular orientation, and more recently 360 complementary connector sets 20 have become commonplace, the 360 connector sets enabling the appliance proper to be set down onto its base in any relative orientation. An example of a connector set requiring predetermined orientation is our CS2 connector set which is described in GB-A-2 241 390 and examples of a 360 connector set

f ( are our CS4/CP7 connector set which is substantially as described in GB-C-2 285 716 and a similar system made and sold by Strix Ltd which is substantially as described in WO-A-9508204.

Cordless appliance connectors at present rely on resilient contacts to 5 take up the tolerances inherent in the mating of an appliance proper with its power base. In the case of Strix's P72 360 cordless, this resilience is in the form of three discrete spring mounted contacts in the power base which mate with three fixed ring contacts in the appliance. In the case of our CS2 (conventional cordless) and CS4 (360 ) systems the resilience is in the form 10 of spring mounted contacts which move.n a horizontal axis, and have a sliding action on the mating rigid contacts. On the CS2 the resilience is in the base component, and on the CS4 the resilience is in the appliance component.

These resiliently mounted contacts tend to be somewhat fragile, and may be damaged in use of the appliance, or during assembly of the product. This 15 arises from the need to keep the spring rate low to avoid excessive mating forces which could tend to push the appliance away from its base, or which may prevent the smooth undocking of the appliance, causing the power base to catch and lift with the appliance.

Objects and Summarv of the Invention: 20 It is the principal object of the present invention to overcome or at least substantially reduce the abovementioned problems.

According to one aspect of the present invention, a 360 connector set for a cordless electrical appliance comprises an appliance connector having

( three terminal pins extending fixedly therefrom in a triangular arrangement and a base connector comprising a central terminal and two concentric ring terminals fixedly positioned therein, one of the terminal pins of the appliance connector being adapted to contact the central terminal of the base connector 5 and the two other terminal pins of the appliance connector being adapted to contact respective ones of the ring terminals, the appliance and base connectors being adapted to be mated together and the base connector being adapted to be resiliently mounted in the base unit of a cordless appliance so as to be capable of accommodating a degree of misalignment between the 10 appliance and base connectors and/or their respective electrical parts.

The above and further aspects of the invention are set forth in the appended claims and will best be understood from consideration of the following detailed description of an exemplary embodiment which is

illustrated in the accompanying drawings.

15 Description of the Drawings:

Fig 1 shows an oblique view of the upper surface of the socket part of the embodiment; Fig 2 shows an oblique view of the underside of the socket part; Fig 3 is similar to Fig 1, with the contact cover and seal removed to 20 show the contacts; Fig 4 shows a cross section through the socket part; Fig 5 shows a cross section through the socket part mounted in the upper moulding of a power base;

( Fig 6 shows a view of the underside of the plug part of the embodiment; Fig 7 shows a section through the plug part; Fig 8 shows a sectional view of the plug part and power base before S engagement; and Fig 9 shows a sectional view of the plug part and power base in engagement. Detailed Description of the Embodiment:

The socket part of the embodiment consists of a main carrier moulding 10 (1) formed of plastics material and housing wo rigid ring contacts (2, 3) and a rigid central contact (4). The ring contacts are housed in slots (5), best seen in Fig 4, and have a cover (6) which provides the necessary electrical safety, limiting access to the contacts from above whilst allowing access to the narrow blades of the mating appliance plug part. Each contact is provided 15 with a tab terminal (I 1,i2,13) which projects below the carrier moulding. An optional seal (7) fommed of a simple rubber (or elastomer) washer provides additional protection against water spillage and the internal fomm of the contact carrier is very open to encourage any water which may enter to quickly drain to avoid electrical safety problems.

20 The carrier moulding assembly, with its contacts, is located on a helical compression spring (8) which holds the assembly upwards against the underside of the power base upper surface. The spring is carried by the power base lower cover which is not shown. The socket has a conical skirt (9)

which locates in a mating feature on the power base moulding, best seen in Fig 5, and has an anti rotation slot ( 10) which locates on a rib (not visible) on the power base moulding (14). The spring allows the carrier assembly to move vertically- typically by around 3nun-and also to rock by a small 5 amount so that the plane of its upper surface can rotate away from horizontal in any direction by about 3 degrees. This amount of rotation will normally be sufficient to accommodate most expected misalignments, but, as with resilience, if more is required then it can be provided.

The mating plug part of the embodiment may take one of two forms.

10 It may either be an X2 element protector control as described in GB-A 2 283 156, with its terminals, including the earth tab, pointing vertically downwards and twisted to lie on arcs whose centre is the axis of the earth tab.

Alternatively it may simply be a carrier moulding with three tabs arranged in the same configuration and providing terminals for connection to the 15 appliance internal wiring. Figures 6 to 9 show a separate plug of this latter form. Either of these configurations provides a set of three downwardly pointing blades (11) arranged so that their axes are not coplanar, their larger flat surfaces are perpendicular to a radius passing through its axis and the axis of the earth tab and their length (projection) is roughly equal. Figures 6 and 7 20 show the blade contacts (11) mounted in a housing (12) which incorporates guidance features to facilitate mating of the plug and socket parts of the connector set in a relatively loose and unbinding fashion.

( The three, non-coplanar, pins can align with the contacts in the socket and can accommodate constructional tolerances, the socket component floating to provide this alignment. In the case of this invention it is envisaged that the central contact should be the earthed contact. In practice the 5 connection of the contacts can be as desired but use of an X2 control as the basis of the plug part would limit the earth to being the central contact because of its geometry.

The configuration of the illustrated plug and socket has some similarity to the Strix P72 arrangement, inverted. The rings of the P72 are in 10 the appliance plug, and the sprin, contacts of the base socket have been replaced by the rigid blades. Although our arrangement is shown with the rings in the base, they could form the plug contacts, and the rigid blade contacts could be provided in the sprung mounted base socket. The illustrated arrangement is preferred as the components are cheaper.

15 The advantages of the invention provide a simple assembly of rigid parts, which are easier to manufacture, and are more robust in service. The float of the socket in the power base gives the necessary compliance to accommodate manufacturing tolerances, and can be made as great as necessary without compromising other features such as contact force and 20 product height.

Having described the invention in the foregoing by reference to an exemplary embodiment it is to be appreciated that modifications and

( variations thereto could be made without departure from the spirit and scope of the invention as set forth in the appended claims.

Claims

( Claims:

1. In or for a cordless electrical appliance a 360 connector set comprising plug and socket parts one of which comprises three concentric terminals and the other of which comprises pin terminals 5 arranged nonco-linearly for contacting respective ones of the concentric terminals when the plug and socket parts are engaged together, the arrangement furthermore being such that with one of said plug and socket parts fixedly secured in the appliance proper and the other resiliently mounted in the base of the cordless appliance a degree 10 of misalignment of the plug and socket parts can be accommodated.

2. In or for a cordless electrical appliance, a 360 connector set comprising an appliance connector having three terminal pins extending fixedly therefrom in a triangular arrangement and a base 15 connector comprising a central terminal and two concentric ring terminals fixedly positioned therein, one of the terminal pins of the appliance connector being adapted to contact the central terminal of the base connector and the other two terminal pins of the appliance connector being adapted to contact respective ones of the ring 20 terminals, the appliance and base connectors being adapted to be mated together and the base connector being adapted to be resiliently mounted in the base unit of a cordless appliance so as to be capable of

( accommodating a degree of misalignment between the appliance and base connectors and/or their respective electrical parts.

3. A 360 connector set as claimed in claim 1 or 2 wherein the connector 5 part on the appliance comprises an integrally formed heating element overtemperature protection control adapted to switch off the supply of electrical energy to the appliance in response to a sensed heating element overtemperature condition.

10

4. A 360 connector set as claimed in any of the preceding claims wherein the resilient mounting of the respective connector part is such as to provide a degree of rotation thereof in addition to a degree of tilting movement.

15

5. A cordless electrical appliance comprising an appliance proper and a base unit, the appliance proper having a connector with a triangular three-point, fixed contact set and the base having a complementary connector with a coaxial, fixed contact set, the base connector being resiliently mounted.

6. A two part electrical connector, one part comprising a triangular three point contact set and the other part comprising a complementary coaxial contact set and being resiliently mounted.

(

7. A 360 electrical connector set in or for a cordless electrical appliance, said electrical connector set being substantially as herein described with reference to the accompanying drawings.

s

8. A cordless electrical appliance comprising an appliance proper and a power base and complementary electrical connectors on the appliance proper and on the power base, the connector on the power base being resiliently mounted so as to be capable of accommodating tolerance 10 variations and minor misalignments in the two connectors.