GB2518786A

GB2518786A - Thermal controls for liquid heating elements

Info

Publication number: GB2518786A
Application number: GB1500440.1A
Authority: GB
Inventors: David Andrew Smith; Robert Henry Hadfield; Antonio Martin Gaeta; Ian Geoffrey White; Robin Keith Moore; Yuan An; Peter Hallam Wright; Jeremy Francis Siddons; Andrew Hunt; Paul Boundy; Simon M Whiteley; Richard Chee Cheung So; Mark Sherratt; Richard William Lindley
Original assignee: Otter Controls Ltd
Current assignee: Otter Controls Ltd
Priority date: 2010-10-14
Filing date: 2011-09-22
Publication date: 2015-04-01
Anticipated expiration: 2031-09-22
Also published as: GB201112936D0; CN202695826U; GB2483745A; GB2484571B; WO2012110825A3; GB2484571A; EP2675326A2; GB201116404D0; GB201104819D0; GB201114267D0; GB201500440D0; GB2518786B; CN202691026U; WO2012110825A2; GB2489288A; CN103561615B; CN103561615A; GB201107507D0; GB2489257A; JP2014505567A

Abstract

A thermal control for a liquid heating element, the control having at least one wire 512 integrated therein for connection to the heating element, wherein the at least one wire 512 is electrically connected to a contact (510), and said at least one wire 512 is an insulated wire. The thermal control may have a contact plate 501 to which the at least one wire is mechanically attached by welding, such as spot welding 513, soldering or brazing and / or by retention means provided on the contact plate. The at least one wire may be resilient so as to bias the distal end against a cold tail of a sheathed heating element or may be sufficiently malleable to be bent around the cold tail prior to welding thereto.

Description

Thermal Controls for Liquid Heating Elements

Field of the Invention

Foil The present invention relates to thermal contrcñs br liquid heating element, in particular to liquid heating elements for electrical appliances and components therefor.

Background of the Invention

[02] One method to reduce the manufacturing costs of an appliance is to simplify the internal wiring of the appliance and in particular the method in which an integrated control and corWess connector, for example the Otter Al series, as described in WO-A- 2004/062455, is connected to the cold tafis of a mechanical sheathed underbloor element.

[031 It is known in the prior art for integrated controls to be connected to the element cold tails via a wiring harness including a combination of sheathed wire tab terminals and receptacles. This method involves problems, such as the overheating of the crimps between the wires and the receptacles, and it is common for the these harnesses to be backed up by an additional welding, brazing or soldering process, if it is possible to gain access for the additional process.

[041 For higher power elements, it is known to provide so-called bus bars' which are electrical conductors stamped and folded out of strip material. The bus bars are provided as an integral part of the control and extend outside the control to be attached, usually by a welding process, onto the element cold tails. Figure Sla shows a typical prior art application in which strip material bus bars 519 make connections between an element cold tafi 40 and a control 60.

[05] The prior art bus bars 519 are effective in overcoming the overheating problem and also simplify the assembly of the appliance; however there are a number of disadvantages.

First, the stamping and folding process generates a large amount of waste material (e.g. as a function of press width versus pitch) and is therefore expensive. Furthermore, for economies of scale, it is necessary to make one size fits all' bus bars 519, which are made longer than is necessary for many applications and are preformed into an arc shape to suit different cold tail positions, both of which add further to the waste and increase the cost. Bus bars 519 are generally manufactured from plain material without insulation. and therefore need to be positioned away from other metal parts so that creepage and cleanmce distance can be met.

Finally the size and shape of the bus bars 519 add complexity to the packaging and generally reduce the number of controls 60 that can he packaged per box.

[061 It is known in the prior art to manufacture a stamped bus bar component incorporating a female connector to connect between control 60 and the element cold tails 40; however this is a complex additional component that relies on a mechanical connection between the bus bar 519 and the control 60 and may be susceptible to overheating if, for example. the connector becomes out of tolenmce.

[071 It is also known in the prior art to provide low cost bare wire conductors between thermostats and elements; however this is only possible where there is sufficient space and material on the electrical connectors of the control to gain access for the welding process.

[081 Typically the electrical connector of an integrated control 60 is either shrouded within, or mounted close to the control main moulding, so it is not practical to gain access for a weld head or other attachment process. It may be possible to extend the conductors to a position outside the control 60, as later described herein; however this would add additional material and may negate a proportion of the cost saving over a bus bar 519 made from strip material.

[09] Furthermore there are risks in allowing the appliance manufacturer to weld a wire 512 onto a conductor in close proximity to the control, particularly as it may be difficult to jig' the process correctly There may he excess heat from the weld (or other attachment method) during the attachment process, which may damage the control and alternatively or additionally a poorly made connection may cause overheating if the joint becomes resistive during use. Additionally it would be difficult to rework if for example the weld process became out of control which may result in the scrapping of an expensive control, or worse stilL damaging the safety critical control during the rework process.

Statements of the Invention

[10] According to a first aspect of the present invention, there is provided a thermal control as claimed in claim 1.

[11] According to a second aspect of the present invention, there is provided a thermal control as claimed in claim 3.

Brief Description of the Drawings

[12] There now follows, by way of example only, a detailed description of prefered embodiments of the present invention, with reference to the Figures identified hdow.

Figure 1 is a schematic cross-section of a cordless liquid heating appliance in an embodiment of the invention.

Figure 5 la is a perspective view of bus bar connections to element cold tails in the

prior art.

Figure SIb is a perspective view of a control in the prior art, showing the positions of contact plates.

Figure Sic is a perspective view of a contact plate in the prior art.

Figure 5 id is a perspective view of a spring connector attached to the contact plate

iii the prior art.

Figure 51e is a perspective view of a wire attached to a contact plate in a first embodiment.

Figure 51f is a perspective view of a wire attached to a contact p'ate in a second embodiment.

Figure 5 ig is a perspective view of a wire in a third embodiment.

Figure 51h is a perspective view of the wire of Figure 51g. attached to a contact plate.

Figure 51 i is a plan view of the attachment of Figure 5 lh.

Figure Sij is a cross-section of a first variant of the attachment of Figure 51g.

Figure 51k is a cross-section of a second variant of the attachment of Figure 51g.

Figure 511 is a perspective view of an end of a wire in a fourth embodiment.

Figure Slm is a perspective view of the wire of Figure 511, attached to a contact plate.

Figure 51 n is a perspective view of a variant of the fourth embodiment.

Figure Sb is a perspective view ola wire in a fifth embodiment.

Figure Sloa is a perspective view of a first embodiment of clamping means for the contact support plate of Figure 5 lo.

Figures Slob and Sloe are perspective views further embodiments of the clamping means for the contact support plate of Figure 5 lo.

Figure Slod is a cross section perspective view through A -A of the clamping means of Figure Sloc.

Figure Sloe is a perspective view of a first embodiment of retention means for the wire conductor of Figures lo and 51 oa to 51 od.

Figure Slof is a perspective view of a further embodiment of the retention means for the wire conductor of Figures Sb and Sloa to Slod Figure Slog is a perspective view of an embodiment of the wire conductor including a resilient contact means.

Figure 5ip is a perspective view of a control having wires attached to its contact plates by any of the embodiments of Figures Sic to 51o.

Detailed Description of the Embodiments

[13] ffi the following description, functionally similar parts carry the same reference numerals between different embodimenk. The drawings are intended to he schematic, and dimensions and angles may not be determined accurately from them unless otherwise stated.

[14] In (he foflowing emhodiments, a hare wire conductor can he incorporated into an integrated control 60 as part ci the control assembly procedure and in so doing provide a fully capable integrated control 520 complete with wire conductors 512 for connection onto the element cold tails 40.

[15] Figure 1 shows schematically a jug kettle with an electronic control, as an example of an appliance to which embodiments of the invention may be applied. k this example, the kettle is a cordless kettle comprising a vessel hody I and a power base 2 having respective body and base cordless connectors 3 and 4, such as 3600 cordless connectors of the type described in patent publication WO-A-94/06285 and/or as sold by Otter Controls Ltd. under the CS4ICS7 (power base socket) and CP7 or CP8 (appliance plug) references. The power base is connectable by a power cord 13 to an electrical power outlet (not shown).

[161 The vessel body 1 comprises a reservoir 5 for containing liquid to be heated, and a base section 6 having a sub-base 19. which forms the bottom surface of (lie vessel hody I. The vessel body I is!èrmed as ajug kettle and therefore has a spout 7, a lid S and a handle 9. Liquid is heated by an clement plate 12 forming the base of the reservoir 5, and including a heating element on the underside (i.e. facing towards the base section 6), connected to receive electrical power from the body cordless connector 3. The element plate 12 may be fitted into tile vessel body using the Easifix (RTM) fitting as described in WO-A-99/17645.

The element may comprise a sheathed element and/or a thick ifim dement. Prefcraliy, the element plate is composed of stainless steel. Most preferably, the clement plate is substantially as described in WO-A-06/83 162. However, at least some embodiments of the present invention are applicahle to liquid heating vessds having an immersed heating element, rather than an element plate.

[171 Where reference is made herein to 3600 (cordless) connectors, it will be understood that the (cmi also covers substantially 360° (cordless) connectors, where connection is offly prevented over the full 360° of relative axial rotation by means designed to limit the relative positions of the connectors and/or by other features that obstruct relative rotation.

[181 Figures 51 a to 5 id illustrate the connection means of the prior art Al series control in which there are provided two fixed contact plates 501 in the position of the hatched circles 500.

[191 The fixed contact plate 501 includes a contact support plate 508 at on end which, S dependent upon the power rating of the appliance. may incorporate a discrete silver (or other low resistance material) contact 510 on the underside. The contact support plate 508 or contact 510 interfaces with a mating resilient spring terminal (not shown) within the control and the contact support plate 508 and resilient spring pair act as a switch to disconnect the power to the element cold tails 40 in response to the bimetal (not shown) and/or trip lever (not shown).

[20] The plate 501 incorporates a male tab terminal connector 507,including an aperture 504 which acts as a retention feature with a mating female receptacle (not shown) for connecting the control 60 to (lie dement cold tails 40 or other part of the appliance 1.

[21] The plate 501 also includes an addition male cleat 505 which allows the assembly of a resilient spring connector 506 for variants of the Al series intended for use with printed elements. The resilient springs 506 include a mating female clench feature 511 enabling a low resistance joint between (lie two parts. The spring 506 may he plated in a low resistance material, for example, sHyer and/or may include a low resistance contact 509.

[22] The plate 501 includes cleats 502 which are post formed 503 during assembly so that the cleats 503 act to secure the plate 501 permanently within the control housing.

[23] In its simplest form, an integrated control 60 with wire type conductors connectors 512 can he manufactured by mechanically attaching a wire 512 onto a standard part within the control 60. for example a contact plate 501.

[241 Figures 5 le to 5 im illustrate embodiments wherein conductive wire 512 is mechanica'ly attached to the contact p'ate 501 prior to assembly into the control 60 so that the assembled part may be installed without any modification to the plate 501 and the moulding of the control 60.

[25] The material for the wire conductor 512 may be drawn wire for malleability and also low resistance to avoid self heating; it would also he preferable to avoid dissimilar metals wherever possible. In the case of the Al series the contact plate 501 is made from brass typically in the range of CVZN 30 to CVZN37. The element cold tails 40 are typically made from plated mild steel or stainless steel. Therefore for this combination of materials the most suitable material for the wire conductor 512 would he brass in the range of CVZN 30 to CVZN37. a

[261 Other materials suitable for the wire conductor 512 may include, but are not limited to, brass outside the range of CVZN3O to CVZN37, phosphor bronze, stainless steel, copper, nickel plated mild steel and copper p'ated mild steel.

[271 The wire conductor 512 may be resilient, so as to bias the distal end thereof against the cold tail 40, and thereby assist with the secunty of the welding process. In further embodiments the distal ends of the wire conductor 512 may act as the resilient part of a switching means between for example, the wire conductor 512, and the cold tail 40.

Alternatively, the wire conductor 512 may be sufficiently malleable to be wrapped or bent around the cold tail 40. thereby assisting with the security of the welding process.

[28] The wire conductor 512 may he hare, or may he provided with electrical insulation (not shown) such as a plastic sleeve for use in appliances in which there are particular creepage and clearance requirements. The insulated sleeving may be attached to the wire conductor 512 helore or alter the control assembly and may he added as part of the appliance assembly.

[29] The drawn wire conductor may he circular, square or rectangular or generally polygonal in cross section, but is preferably circular with a diameter of between 1 and 2 mm [30] The present embodiments do not preclude the use of strip material for the conductor 512; howevcr it is cxpcctcd that this will be less malleablc in the flat plane and more expensive than drawn wire.

[31] The present embodiments illustrate components from the Otter Al series hut do not preclude the use of similar arrangements in other contro' types.

[32] Figure Sle schematically illustrates a conductor 512 joined by a spot weld 513 along the wide edge of the tab terminal 507.

[33] For Ihis, and all other embodiments that rely upon a weld 513, only one weld is shown; however additional welds 513 can be used for extra security, and the length of contact of the conductor 512 with the plate 501 can he increased or decreased as required.

[34] Other methods of attachment may be used place of the weld 513, including but not limited to friction welding, brazing and soldering.

[35] The embodiment of Figure SIc is a variant of that of Figure SId in which the conductor wirc is attached to the contact support plate 508.

[36] lii this and other embodiments the wire 512 may be profiled so that it runs alongside the tab terminal 507 within the housing or shroud 521 of the control 520. This will help support the wire and protect the weld 513 if, for example, the wire conductor 512 is to be bent or formed as part of the assembly onto the cold tails 40.

[37] Figure SIg to 51i show a variant of the previous embodiments wherein the wire conductor 512 is preformed so that is can be threaded through the retention aperture 504 in the tab terminal pail 507 of the contact plate 508 prior to attachment 513. In this case, the retention aperture 504 acts as a jig to support the wire conductor prior to attachment to the contact plate 508 and will act to support the wire conductor 512 during use.

[38] Figure 5 lj and 51k illustrate cross sections of variants of the above embodiments where the wire conductor 512 is swaged or planished 514 after being threaded through the retention aperture 504 in order to provide additional mechanical strength to the connection.

In the ease of the embodiment illustrated in Figure 51j, both sides 514 of the wire conductor 512 may be planished. In the case of the embodiment illustrated in Figure 51k the end of the wire conductor 512 is cropped short and a rivet 515 is formed during the planishing process.

in both embodiments it may be possible to rely entirely on the planish 514 or rivet 515 to provide the electrical integrity hut a further attachment 513 may also he employed.

[39] Figures 511 and 5 im illustrate a further embodiment in which the end of the wire conductor 512 is flattened and a female clench feature 511 is formed so that the wire conductor can he attached to the male clench feature 505 in the same manner as the previously described resilient pror art resilient spring 506. The wire conductor may then be supported and/or attached along the top of, or side of, the contact plate 501.

[40] Figure SIn shows a further variant of the previous embodiment where an additional weld platform 516 is provided on the contact plate 501. It is preferred that the conductor wire 512 is attached to the plate 516 before assembly into the control 520, however alternatively the conductor wires 512 may be added during the assembly of the appliance 1.

[41] Figures Sb to Sloe illustrate a preferred low cost implementation of a wire conductor 512. In these embodiments, the combined plate 508 and conductor wire 512 are replaced by one wire conductor 512 in which the control end 518 is planished so that a contact 508 may be welded or otherwise fixed on either the lower or upper surface. An additional member 591 may he provided in or around the control 520 to support the wire conductor 512 and further members 517 maybe provided to secure the wire conductor 512 in a fixed position within the control 520.

[42] lii this way. the wire conductor 520 of this embodiment may perform a similar function to the previously described contact plate 508 and may interface with the previously described resilient spring 137 and act to disconnect the power to the appliance in response to a bimetal or other switch actuator (not shown).

[43] Figure SIn illustrates a first embodiment of the combined wire conductor and contact plate in which a contact portion 544 is provided on the underside of the planished portion 518 and at least one member 5 17a and/or 5 17b provided either end of the planished portion for support.

[441 The contact portion 544 may be flat or may be profiled to form a raised contact portion arid may be plated; or as previously described may include a discrete silver or other low resistance contact 510. As illustrated in Figure Sb, the planished portion 518 is elongate, however in lurther embodiments an alteniatively sized and/or shaped panished portion may be sufficient to provide a platform for a discrete contact. Alternatively the wire may not be planished and the outer surface of the wire may foirn the contact portion 544.

[45] At least one of the members 517a includes some lorm of damping means 517a so that the wire conductor 512 is held firmly against the upward force that may be applied by the resihent spring (not shown). The wire conductor 512 maybe proffled and at least one of the clamping means 517 profiled in a colTesponding manner so that the wire conductor 512 maybe prevented from rotating.

[46] Figure SIoa illustrates a further embodiment in which a member 591 may he provided in or around the control 520 to support the wire conductor 512 and slotted clamping means 5 17c and 517(1 may be provided to secure the planished portion 518 in a fixed position.

[47] As illustrated. the slot in clamp 517c may he provided with a recess 570 so that a discrete contact 510 may be applied to the planished portion 518 prior to assembly and the planished portion 518 and contact portion 544 may then be assembled through the clamp 517c. The corresponding resilient spring portion 137 (illustrated in dotted lines) is shown above the planished portion in a closed position.

[48] In this and further embodiments, the direction of the actuation and the contact positions may be reversed. In which case the contact portion 544 may be provided on the underside of the planished portion 518 and an aperture may he formed in the support plate 591 so that the resihent spring 137 may act from below.

[491 The embodiment illustrated in Figure 5lob is a variant of the first embodiment of Figure 5 ba, in which the support member 591 is provided with pairs of individual clamping means 517e and 517f. Advantageously the members 517 may provide a click fit arrangement so that the planished portion 518 may he assembled from above. The planar portion 518 may include indents (not shown) in the region of the clamps so that the lateral movement is prevented.

[50] In further for example as illustrated in Figures Sloe and Sled, the planished portion 518 may be provided with a part shear 572 or other feature so that the planished portion 518 may be easily inserted into the clamp 517 but may be held firmly in the lateral position once inserted. The clump 517 may be provided with a corresponding recess 571 that may help in the retention of the planished portion 518.

[51] lii further embodiments, a second operation. for example a fold or stamp. may take place to secure the planished portion 518 within the clamping means 517.

[52] In the case that any part shear 572 substantially reduces the cross sectiona' area oi the wire conductor 512 then it is preferred the part shear is positioned between the contact area 544 and the end of the planished portion 518 so that the current carrying capability of the wire conductor is not compromised.

[53] Figures Sloe and Slof illustrate further embodiments in which there are provided retention means S 17h and SI 7i for the wire conductors 512.

[54] Figure Slog illustrates an alternative embodiment in which the planished portion 518 acts as a resilient spring of tile switching means and interlace with a fixed contact (not shown) of the control 520. The planar portion in this alternative embodiment has an elongate form and is secured by the previously descnbed clamping means and may be acted upon by a push rod or other actuator as indicated by the arrow.

[55] In controls in which additional switching means are required, for exampk to switch an additional heating means, it is envisaged that the wire conductors 512 may include more than one contact area 544.

[56] ffi appliances where additional electrical components such as a steam control may be connected in series between the contr& 520 and the element cold tails 40 it may he possible to weld or connect additional conductors to a standard wire conductor 512 or in alternative enihodinients the end of the wire conductor 512 may be stamped to form for example a standard male tab terminal or may be provided with a female connector or other connector type attached to the wire conductor 512.

[57] In appliances that require additional electrical components to operate in parallel with the heating elemcnt 12, for example intemal lighting, then additional conductors may be connected, by for example welding onto ihe wire conductor 512 between the control 520 and the cold tails 40.

[581 Figure Sip illustrates a control 520 complete with wire conductors 512 attached to the control at at least one point within (he shroud 521. The wire conductors 512 may be in an arc form in readiness for attaching to the cold tails 40. For ease of packaging the wire conductors may be supplied folded, bent or formed around the control 520, so as to take up less space in the package or box.

[59] The embodiments illustrated in Figures 510 and 5 ba to Slog advantageously provide a very cost effective complete conductor assembly with little or no waste material.

so that the overall cost of an integrated control, for example control 520, is optimised.

Alternative Embodiments [601 The embodiments described above are illustrative of rather than limiting to the present invention. Alternative embodiments apparent on reading the above description may nevertheless fall within the scope of the invention.

Claims

Claims 1. A thermal control for a liquid heating elcment, the control having at least onc wire integrated therein for connection to the heating element, wherein the thermal control has a contact to which the at least one wire is connected, and said at least one wire is an insulated wire.
2. The theirnal control of claim 1. wherein the contact comprises a contact plate and the at least one wire is attached to the contact plate by welding, soldering or brazing and/or by retention means provided on the contact plate.
3. A (hernial control br a liquid heating element. the control having at least one wire integrated therein, for connection to the heating element, wherein the thermal control has a contact plate to which at the least one wire is mechanically attached by welding, soldering or brazing and/or by retention means provided on the contact plate, and said at least one wire is an insulated wire.
4. The thenmil control of claim 2 or 3. wherein the wire is welded, soldered or brazed to a platform provided on the contact plate.
5. The thermal control of claim 2 or 3, wherein the retention means act as a jig to support the wire prior to being attached thereto and to support the wire during use.
6. The thenmil control of any one of claims 2 to 5, wherein the contact plate carries and/or incorporates at least one switch contact. for the control.
7. The thermal control of any one of claims I to 6, wherein the wire is connected to the control within a shroud or housing of the control.
8. The thermal control of any one of claims I to 7, having a plurality of said wires integrated therein.
9. The thermal control of any one of claims 1 to 8. wherein the distal end of said at least one wire is arranged for welding directly to a contact portion of the liquid heating element.
10. The thermal control of claim 9. wherein the contact portion is a cold tail of a sheathed heating clement.
11. The thermal control of claim 10, wherein the wire is sufficiently malleable to be bent around the cold tail of the sheathed heating clement prior to welding thereto.
12. The thermal control of any of claims 1 to 10, wherein the wire is resilient so as to bias the distal end thereof against a cold tail of a sheathed heating element.
13. The thermal control of any one of claims 2 to 6, or any one of claims 7 to 12 when dependent thereon, wherein the wire passes through an aperture in the contact plate.
14. The thermal control of claim 13. wherein the wire is swaged or planished against the contact plate.
15. The thermal control of claim 13 or 14, wherein the wire forms a rivet through the aperture.
16. The thermal control of any of claims I to 15. wherein the proximal end of the wire is flattened.
17. The thermal control of claim 16, wherein the flattened end of the wire is clenched to a contact portion of the control.
18. The thermal control of any one of claims I to 17, wherein the wire is substantially round in cross-section.
19. The thermal control of any of claims I to 18, wherein the wire forms or carries at least onc switch contact for the control.
20. The thermal control of any of claims I to 18, wherein the proximal end of the wire forms a resilient spring terminal.
21. The thermal control of any of claims 1 to 20, wherein the distal end of the wire is flattened to form a terminal connector.
22. The thermal control of claim 21, wherein the flattened distal end of the wire includes an aperture therein for securing a complementary connector.
23. The thermal control of any of claims 1 to 22, wherein the wire is formed or comprises a contact portion and wherein there is provided means to secure and support the wire within the control.
24. The thermal control of claim 23. wherein the securing means is provided to secure and support the proximal end of the wire against a Ièrce applied hy a resilient spring of the switching means of the control.
25. The thermal control of claim 23 or 24, wherein the securing means is provided to secure and support the contact portion of the wire in a horizontal direction.
26. The thermal control of claim 23 or 24, wherein the securing means is provided to secure and support the contact portion of the wire in a vertical direction.
27. The thermal control of claim 23 or 24, wherein the securing means is provided to secure and support the distal end of the wire in a rotational direction.
28. The thermal control of claim 23, wherein the wire is profiled for mutual engagement with securing means to secure and support the wire in a rotational direction.
29. The thermal control of any one of claims 23 to 28, wherein the securing means comprises at least one clamp with a slot for allowing the proximal end of the wire to be secured thereto.
30. The thennal control of claim 29, wherein the proximal end of the wire comprises a raised contact and the at least one clamp is provided with a recess for allowing the raised contact to pass through during assembly.
31. The thermal control of claim 29, wherein a planish portion of the wire is provided with a shear portion for engaging said clamp.
32. The thermal control of claim 31. whercin thc plathsh portion of the wirc is inscrted into the securing means.
33. The thermal control of claim 31 or 32, wherein the shear portion is positioned between the contact portion and the proximal end of the wire so that the carrying capacity of the wire is not compromised.
34. The thermal control of claim 29, wherein the proximal end of the wire comprises a resilient or click lit portion for engaging said clamp.
35. The thermal control of any one of claims 23 to 28, wherein the securing means comprises a snap or click fit arrangement to allow the proximal end of the wire to be secured thereto from above.
36. The thermal contr& ol any one ol claims 23 to 35, wherein the at east one contact is provided on the underside of the wire for contacting the resilient spring of the switching means of the control via an aperture provided in the control so the resilient spring contacts the at least one contact from above.
37. The thermal control of any one of claims I to 36, wherein additional conductors are welded to the at least one wire to provide power to additional electrical components such as lighting.
38. A liquid heating appliance comprising the thermal control of any of claims 1 to 37, wherein at least one said wire is welded to the heating element.
39. A liquid heating appliance comprising the thermal control of any one of claims 1 to 37.wherein the wire is provided with horizontal and/or vertical resilience so that. the wire resiles against at least one corresponding contact portion of the liquid heating element and/or liquid temperature sensor to control the position of the weld, braze or other attachment means.
40. The liquid heating appliance of claim 38 or 39, wherein the distal end of the wire forms a ptut of at least one switching means for the appliance.
41. The liquid heating appliance of claim 40, wherein the distal end of the wire is resilient.
42. The liquid heating appliance of any one of claims 38 to 41, further comprising a liquid temperature sensor, wherein at least one said wire is welded to a connector of the liquid temperature sensor.
43. The liquid heating appliance of claim 42, wherein the liquid temperature sensor comprises a steam sensor.
44. A method of securing the wire of any one of claims I to 43, wherein the wire is secured in horizontal and vertical dircctions to provide horizontal and vertical resilience.
45. The method of securing the wire of claim 44, wherein the horizontal and vertical resilience of the wire provides a position for the cold tail to he secured thereto.