GB2147747A - Electrical connector - Google Patents

Abstract

The connector is preferably of the type which has temperature control means (9), including a temperature sensing probe (34), for controlling the temperature of a self-contained cooking vessel. The connector comprises two separable parts held together by a magnetic coupling (25, 30). Each part has at least two terminals, the terminals of the one part making electrical contact respectively with the terminals of the other part when the parts are held together by the magnetic coupling. <IMAGE>

Description

SPECIFICATION Electrical connector This invention relates to an electrical connector and particularly but not exclusively to such a connector of the type which has temperature control means, including a temperature sensing probe, for controlling the temperature of a self-contained cooking vessel.

Electrical connectors of the aforementioned type are known but because of the requirement that the connector has to be a good fit in a recess or socket provided in the cooking vessel in order to acquire intimate heat conduction from the cooking vessel there is a danger that should the electrical supply lead to the connector be caught by a human or animal the cooking vessel will be pulled off its supporting surface or tipped over with the consequent risk of harming, e.g. burning, the human or animal or starting a fire.

The invention provides in one aspect an electrical connector comprising first and second separable parts held together by a magnetic coupling, each part having at least two electrical terminals, the two terminals of the first part making electrical contact respectively with the two terminals of the second part when the parts are held together by the magnetic coupling.

Preferred and/or optional features of the one aspect of the invention are set forth in claims 2-8.

The invention provides in another aspect an electrical appliance provided with a connector according to the one aspect of the invention.

The invention will now be more particularly described with reference to the accompanying drawings, in which: Figure 1 is a vertical section through one embodiment of an electrical connector according to the invention, and Figure 2 is a horizontal section through the electrical connector of Figure 1.

Referring to the drawings, the connector shown therein comprises two parts 10 and 11 and is particularly but not exclusively designed for use with a self-contained electrically heated temperature controlled cooking vessel which is completely immersible in liquid for cleaning purposes, such vessels now being well known.

The part 10 comprises a plastics housing 12 provided with an opening 13 in which is fitted a nozzle 14 through which a flexible electrical supply lead 15 enters the housing. The lead 15 conventionally includes three conductors 16, 17 and 18, two of which 16 and 17 are connected to sprung terminal blades 19 and 20 housed in sockets 21 and 22 respectively in the housing 12 and the third of which 18 is connected to a contact 23. The housing 12 is in fact in two parts 12a and 12b fixed together by a screw fastener 24 and the housing 12 accommodates a permanent magnet 25.

The part 11 also comprises a plastics housing 26 which is in two parts 26a and 26b fixed together by screw fasteners one of which is shown at 27. At one end the housing 26 has two terminals 28 and 29 which project beyond the housing 26 and which make electrical contact with the terminal blades 19 and 20 respectively when the parts 10 and 11 are held together. The housing 26 also has a ferromagnetic plate 30 at said one end. The plate 30 serves two purposes. Firstly, on conjunction with the magnet 25 it holds the two parts 10 and 11 together. Secondly, when the two parts 10 and 11 are held together it makes contact with contact 23 and is connected to a conductor 31 which is a marginal earth conductor.At its other end, the housing 26 accommodates two socket terminals 32 and 33 and an elongate temperature sensing element in the form of a probe which forms part of temperature control means 9 and which extends well beyond the housing 26.

The probe 34 comprises a stainless steel sleeve 35 having a high coefficient of expansion surrounding a rod 36 which has a low coefficient of expansion and which is welded to the sleeve at the tip of the probe, i.e. at the end of the probe remote from the housing 26. An arm 37 is welded to the sleeve 35 and carries at its free end a ceramic break contact 38. The rod 36 is also welded to the arm 37 intermediate the ends thereof. Terminal 18 is connected by a conductor 39 directly to socket terminal 32, whereas terminal 2 is connected to socket terminal 33 via a conductor 40 and terminal 41, break contact set 42 and terminal 43 of the temperature control means 9, and a temperature safety device 44.A control knob 45 is also provided to adjust the degree to which the arm 37 has to be deflected by the bimetal effect of the probe 34 in order to separate contacts 42a and 42b of break contact set 42 so as to interrupt the electrical connection between terminal 29 and socket terminal 33.

A neon lamp 46 is connected between socket terminals 32 and 33 to indicate whether the current circuit is interrupted.

When the connector is connected to the cooking vessel and the heating element of the cooking vessel is energised, the probe will be heated and, at a temperature dependent on the position of the control knob 45, the ceramic break contact 38 will move with arm 37 to separate the contacts 42a and 42b. The heating element and probe 34 will then cool down to allow the contacts 42a and 42b to make contact again. This process will be repeated so that the temperature of the probe 34 and hence that in the appliance is maintained within specified limits. Should a human or an animal catch or trip over the supply lead 15, the two parts 10 and 11 will readily separate to prevent an accident from occurring as the coupling between the two parts 10 and 11 is almost entirely due only to the magnetic attraction between the magnet 25 and the plate 30, the terminals 28 and 29 being a loose fit in sockets 21 and 22 housing the terminal blades 19 and 20.

The safety device 44 is provided to permanently disconnect the current supply in case the temperature control means fails and the temperature rises to an excessive level.

The above described connector need not necessarily be used with cooking vessels but could be used with other appropriate appliances and indeed it need not necessarily include temperature control means but could be, for example, a two part connector for connection to an electric kettle or coffee percolator.

Claims (12)

1. An electrical connector comprising first and second separable parts held together by a magnetic coupling, each part having at least two electrical terminals, the two terminals of the first part making electrical contact respectively with the two terminals of the second part when the parts are held together by the magnetic coupling.

2. The connector of claim 1, wherein the first part is connected to a flexible electrical supply lead and the second part is connected to or is connectible to an electrical appliance and has temperature control means, which includes a temperature sensing element, for interrupting the electrical supply to the appliance when the sensing element senses a temperature above a predetermined value.

3. The connector of claim 2, wherein the temperature sensing element comprises an elongate probe.

4. The connector of claim 2 or claim 3, wherein the temperature control means is adjustable for varying the aforesaid predetermined value at which the supply to the appliance is interrupted.

5. The connector of any one of claims 2-4, wherein the second part further comprises a temperature safety device for interrupting the supply to the appliance should the temperature control means fail and the temperature rises to an excessive level.

6. The connector of any one of claims 2-5, wherein a neon lamp is provided for indicating whether the supply to the appliance is interrupted or not.

7. The connector of any one of the preceding claims, wherein the magnetic coupling comprises a permanent magnet in one of the first and second parts and a ferromagnetic part in the other of the first and second parts.

8. The connector of claim 7, wherein the permanent magnet is in the first part and the ferromagnetic part is in the second part.

9. An electrical appliance provided with an electrical connector as claimed in any one of the preceding claims.

10. The appliance of claim 9, wherein the connector is removable as a whole from the appliance.

11. The appliance of claim 9 or claim 10, wherein the appliance is a self-contained cooking vessel.

12. An electrical connector substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.