Control unit, liquid heating appliance and heat diffusion plate

Abstract

The utility model discloses a control unit, a liquid heating appliance and a heat diffusion plate. A control unit (16) for a liquid heating appliance comprises a switch for controlling the supply of power to an electric heater, a bimetallic element (30a, 30b) for opening the switch at a predetermined temperature, and a mounting plate (32) mountable to a bottom side of a thermal diffusion plate of the electric heater. The mounting plate (32) comprises one or more screw-free fasteners (22a, 22b) arranged to cooperate with one or more corresponding fastener seats in the thermal diffusion plate to provide screw-free fastening between the control unit (16) and the thermal diffusion plate. Each of the screwless fasteners (22a, 22b) defines a "U"-shaped slot.

Description

Technical Field

[0001] The utility model relates to a control unit for a liquid heating appliance and the liquid heating appliance comprising the control unit. Background Art

[0002] Liquid heating appliances, such as kettles, typically comprise an electric heater comprising a heat diffuser plate arranged to transfer heat from an electric heating element to a volume of liquid to be heated. A control unit for the liquid heating appliance is typically mounted to the heat diffuser plate and is configured to control the supply of power to the heating element in dependence on the temperature of the heat diffuser plate.

[0003] It is generally desirable that the control unit be tightly and securely mounted to the heat diffuser plate to provide sufficient heat transfer between the heat diffuser plate and the control unit so that the control unit can reliably detect the temperature of the heat diffuser plate (and thus the temperature and even the presence of liquid within the instrument).

[0004] Typically, the control unit is mounted to the underside of the heat diffuser plate and then secured in place by a plurality of screws extending through apertures in the control unit into corresponding threaded holes in the heat diffuser plate.

[0005] The applicant has recognised that current methods for mounting and securing a control unit to a heat diffuser plate are cumbersome and time consuming. The present invention therefore seeks to provide an improved securing mechanism when mounting a control unit to a heat diffuser plate of a liquid heating appliance. Utility Model Content

[0006] When viewed from a first aspect, the utility model provides a control unit for mounting to the bottom side of a heat diffusion plate of an electric heater of a liquid heating appliance, wherein the control unit comprises:

[0007] a switch for controlling the supply of power to the electric heater;

[0008] a bimetallic element operable at a predetermined temperature to open a switch to interrupt the supply of power to the electric heater; and

[0009] A mounting plate including one or more screwless fasteners arranged to cooperate with one or more corresponding fastener seats in the heat diffuser plate to provide screwless fastening between the control unit and the heat diffuser plate when the mounting plate is mounted to the underside of the heat diffuser plate.

[0010] It will therefore be appreciated that the present invention provides a novel screwless fastening mechanism for fixing a control unit to a heat diffuser plate of a liquid heating appliance. Since the control unit includes its own screwless fastener as part of the mounting plate, the control unit can be installed and fastened in a standalone operation without requiring any separate fasteners. This can improve the ease with which the liquid heating appliance, in particular the control unit and / or the heat diffuser plate, can be assembled. Furthermore, reducing the total number of components required to fix the control unit to the heat diffuser plate helps to reduce the time spent assembling the heater / appliance as well as the material and labor costs.

[0011] The heat diffuser plate is preferably substantially flat. The heat diffuser plate may be aluminium. The liquid heating appliance preferably comprises a liquid heating vessel for containing liquid heated by the electric heater. Preferably, the heat diffuser plate is arranged to be mounted (e.g. brazed) to the underside of the base of the liquid heating vessel of the appliance. This provides thermal communication between the heat diffuser plate of the electric heater and the liquid heating vessel, thereby allowing the contents of the liquid heating vessel to be heated by the electric heater.

[0012] In some embodiments, the electric heater comprises an electric heating element, preferably a sheathed electric heating element. The electric heating element can be mounted on the bottom side of the heat diffusion plate. The electric heating element can be a conventional "horseshoe" structure with electrical terminals at both ends. In some embodiments, the heating element extends substantially around the periphery of the heat diffusion plate. When the control unit is mounted to the bottom side of the heat diffusion plate (e.g., in the center), the electric heating element can surround the control unit.

[0013] The control unit may include a cordless electrical adapter component and a corresponding base electrical connector component. The cordless electrical adapter component and the corresponding base electrical connector component may be of a type that can mate regardless of their relative angular orientation, or at least of a type that can mate over a wide angular range (e.g., at least 340°, preferably up to 360°). Suitable cordless connectors of this "360° type" are described in WO95 / 08024 and WO01 / 28294, and are available as P72 or P76 connector components from Strix.

[0014] The base electrical connector part may comprise tabs for electrical connection to a mains supply cable, or the mains supply cable may be integral with the connector part.Preferably, the base electrical connector part is mounted on a power supply base station for the liquid heating appliance.

[0015] The cordless power adapter component may include at least two mating conductors for connecting to a live pole and a neutral pole of a power circuit. There may also be an additional ground connection. In some embodiments, the cordless power adapter component is a 3-pole conductor component (e.g., for mating with a P72 connector of Strix). In other embodiments, the cordless power adapter component is a 5-pole conductor component (e.g., for mating with a P76 connector of Strix). This 5-pole connector provides an electronic signal connection as well as a power connection.

[0016] In some embodiments, the control unit further comprises a trip bar for allowing a user to manually operate the switch. The trip bar is preferably operable to close and / or open the switch to control the power supply to the electric heater. For conventional appliances that only use screws to fasten the control unit to the heat diffusion plate, the screwdriver used to tighten the screws may damage the trip bar. Some existing solutions to this problem include designing the trip bar to include a cutout that facilitates the insertion of a screwdriver.

[0017] However, the applicant has found that this is not the best solution to the problem, as it imposes unnecessary design constraints on the trip bar. The present invention overcomes this problem by providing a screwless fastening, which can eliminate the need for a screwdriver or similar tool to be used near the trip bar. Therefore, the risk of damaging the trip bar can be reduced.

[0018] Preferably, the switch is arranged to control the supply of power from the cordless electrical adapter part to the heater via the power supply circuit. The switch may comprise a (e.g. first) movable electrical contact mounted on a (e.g. first) movable member. Preferably, the switch comprises a (e.g. first) fixed electrical contact in the power supply circuit. Preferably, the movable electrical contact is arranged to cooperate with the fixed electrical contact so as to allow power to be supplied to the electric heater when the movable member is in the closed position.

[0019] Preferably, the bimetallic element is capable of operating at a predetermined temperature to move the (e.g., first) movable member from a closed position to an open position, in which the (e.g., first) movable electrical contact is separated from the (e.g., first) fixed electrical contact to open the switch, thereby interrupting the power supply to the electric heater.

[0020] The bimetallic element is preferably arranged to detect a temperature within the liquid heating appliance. The temperature may represent the temperature of the liquid within the liquid heating vessel. The temperature may be the temperature of the electric heater. The temperature may be the temperature of the heat diffusion plate.

[0021] The predetermined temperature may be variable (e.g., adjustable). The predetermined temperature may correspond to a desired temperature to which the liquid in the liquid heating vessel is to be heated. The predetermined temperature may correspond to a desired state of the liquid in the liquid heating vessel (e.g., boiling). In some embodiments, the predetermined temperature corresponds to a temperature within the appliance (e.g., the temperature of a heat diffuser plate) during an overheating (e.g., "dry boil") condition.

[0022] In some embodiments, the switch includes a second movable electrical contact mounted on the second movable member. The second movable electrical contact is arranged to cooperate with a second fixed electrical contact in the power circuit in the closed position of the second movable member. The control unit may include a second bimetallic element. Any or all features of the first movable electrical contact, the first movable member, the first fixed electrical contact and the (first) bimetallic element may (and preferably) be applied to the second movable electrical contact, the second movable member, the second fixed electrical contact and the second bimetallic element, respectively.

[0023] Preferably, the (e.g. first or second) bimetallic element is arranged on an upper surface of the control unit. Preferably, the bimetallic element is arranged so that when the control unit is mounted to the bottom side of the heat diffusion plate, the bimetallic element is in thermal conductive communication with the heat diffusion plate. Preferably, the bimetallic element is arranged to contact the bottom side of the heat diffusion plate when the control unit is mounted to the heat diffusion plate. This means that when the control unit is mounted to the bottom side of the heat diffusion plate, the bimetallic element can be arranged to be in good thermal conductive communication with the heat diffusion plate. As a result, the bimetallic element can more reliably detect the predetermined temperature, for example by accurately detecting the temperature of the heat diffusion plate (and therefore, for example, the temperature of the liquid in the appliance). This can allow the bimetallic element to operate more reliably at the predetermined temperature.

[0024] In some embodiments, the control unit includes a control body. The control body is preferably made of plastic or a plastic composite material. The control body can form a mounting component. However, in a preferred embodiment, the control body is separate from the mounting component. The mounting component can be mounted on the control body. The mounting component may include a mounting plate for mounting the control unit to the bottom side of the heat diffusion plate. The mounting plate is preferably metal. The mounting component is preferably substantially flat. The mounting plate preferably extends in a substantially horizontal plane. The bimetallic element is preferably mounted on the upper surface of the mounting component. Preferably, the bimetallic element is mounted on the mounting component so that when the control unit is mounted to the bottom side of the heat diffusion plate, the bimetallic element is arranged between the mounting component and the heat diffusion plate.

[0025] The bimetallic element is preferably a snap-acting bimetallic actuator. The snap-acting bimetallic actuator may be associated with a push rod, which is operated by the actuator to move the movable member to the disconnected position. The snap-acting bimetallic actuator may be arranged to be aligned with (e.g. above) the movable member. The push rod may extend downwardly from the snap-acting bimetallic actuator toward the movable member. The predetermined temperature may correspond to the temperature of the heat diffuser plate during an overheat (e.g. "dry boil") condition.

[0026] One or more screwless fasteners and one or more fastener seats can be arranged to cooperate so that one or more screwless fasteners are received in one or more corresponding fastener seats. In a preferred set of embodiments, one or more screwless fasteners are arranged on the upper surface of the control unit, for example on a mounting plate of the control unit. The one or more screwless fasteners are preferably lugs. Preferably, the lugs are mechanical lugs (rather than electrical lugs or contacts). Preferably, the lugs are solid, i.e. they do not define any apertures, in particular the lugs do not include apertures for receiving screws. This helps to provide a secure connection between the screwless fasteners and the corresponding fastener seats.

[0027] Preferably, one or more screwless fasteners protrude from the mounting plate. One or more screwless fasteners may protrude vertically upward from the mounting plate. However, in a preferred embodiment, one or more screwless fasteners protrude laterally from the mounting plate, i.e. in a plane parallel to the horizontal plane of the mounting plate. For example, one or more screwless fasteners may protrude laterally from the periphery of the mounting plate. Preferably, one or more screwless fasteners protrude from the mounting plate so that when the control unit is mounted to the heat diffusion plate, one or more screwless fasteners protrude in a plane substantially parallel to the plane of the heat diffusion plate. In other words, preferably, one or more screwless fasteners are arranged so that when the control unit is mounted to the heat diffusion plate, the screwless fasteners and the heat diffusion plate are substantially parallel. Therefore, one or more screwless fasteners are arranged to hold the mounting plate so that its horizontal plane is parallel to the horizontal plane of the heat diffusion plate.

[0028] In some embodiments, one or more screwless fasteners protrude in the same plane as the mounting plate. However, in a preferred embodiment, one or more screwless fasteners protrude in a plane below the plane of the mounting plate. Just as (or instead of) one or more screwless fasteners protrude in a plane below the plane of the mounting plate, one or more screwless fasteners preferably protrude in a plane below the bimetallic element (which may be mounted on the upper surface of the mounting plate). Positioning the screwless fasteners in a lower plane than the bimetallic element can help ensure that when the control unit is mounted to the electric heater, the bimetallic element is sufficiently compressed (e.g., slightly flattened) against the bottom side of the heat diffuser plate, thereby providing the required thermal conductivity communication for reliable operation of the bimetallic element at a predetermined temperature.

[0029] It will be appreciated that terms such as "below", "lower" and "above" used herein are relative to the intended orientation of the liquid heating appliance when it contains liquid to be heated, and therefore relative to the direction in which gravity acts on the liquid.

[0030] In some embodiments, one or more screwless fasteners are "L" shaped, comprising a vertical portion and a horizontal portion, wherein the vertical portion extends vertically (downward) from the mounting plate, and the horizontal portion protrudes from the end (lower end) of the vertical portion. The horizontal portion is preferably parallel to the plane of the mounting plate.

[0031] One or more screwless fasteners may be substantially flat. However, in a preferred embodiment, the fastener is trough-shaped. For example, each of the one or more fasteners may define a 'U'-shaped trough, the U-shape being defined in a plane substantially perpendicular to the direction in which the fastener protrudes. The U-shape is preferably defined in a plane substantially perpendicular to the horizontal plane of the mounting plate. Preferably, each of the fasteners includes a flat base plate portion disposed between two side wall portions. The base plate portion and the side wall portion preferably define a 'U' shape together. This shape may impart greater rigidity to the fastener, thereby improving the firmness of the fastening between the control unit and the heat diffusion plate. The shape of the U-shaped trough may be designed to be received in a corresponding aperture of a corresponding fastener seat.

[0032] In some embodiments, a plurality of screwless fasteners are provided. In such embodiments, preferably, at least two of the screwless fasteners are parallel to each other. This can facilitate mounting the control unit to the heat diffuser plate, as the two or more fasteners can be engaged with corresponding fastener seats by moving the control unit in only one direction (e.g., the direction in which the fasteners are parallel).

[0033] One or more fastener seats may be arranged on the bottom side of the heating plate. The fastener seats may include loops. For example, each of the one or more loops may be shaped to receive a corresponding lug. The one or more fastener seats may be mounted to the heat diffusion plate. However, preferably, the one or more fastener seats are integral with the heat diffusion plate. The one or more fastener seats may include cutouts that are bent out of the plane of the heat diffusion plate. This may allow the heat diffusion plate to be manufactured more easily and at a lower cost. This may also reduce the number of steps required to mount the control unit to the heat diffusion plate, since both the fasteners and the fastener seats are already provided on the components to be mounted together.

[0034] In embodiments where one or more fastener seats include cutouts that are bent out of the plane of the heat diffuser plate, the cutouts may be flaps that are folded out of the plane of the heat diffuser plate. Preferably, the flaps have a first edge connected to the heat diffuser plate and a free edge. The flaps preferably include an aperture between the first edge and the free edge. The aperture may be shaped to receive a corresponding tab. Thus, the flaps including the apertures define a loop. The flaps are preferably substantially planar.

[0035] The baffle is preferably folded out of the plane of the heat diffuser plate around the first edge. In other words, the first edge can serve as a hinge for the baffle. One or more fastener seats are preferably folded out of the plane of the heat diffuser plate by about 90 degrees. Preferably, each baffle is connected to the heat diffuser plate only by the first edge.

[0036] Preferably, the aperture is formed by removing material from the heat diffuser plate (eg by removing material from the baffle). The aperture is preferably (eg entirely) formed within the baffle. The aperture is preferably (eg completely) surrounded by the periphery of the baffle.

[0037] Each of the one or more fastener seats preferably defines an aperture for receiving a corresponding fastener of the one or more fasteners. Preferably, the angle between the plane of the aperture and the plane of the heat diffuser plate is greater than zero (i.e., preferably, the aperture is not in the plane of the heat diffuser plate). This may improve the ease with which the control unit can be slid into place. The plane of the aperture may be substantially perpendicular to the plane of the heat diffuser plate.

[0038] Preferably, the width and / or height of the aperture of each fastener seat is substantially equal to the width and / or height of the corresponding screwless fastener arranged to cooperate with the fastener seat. This can provide a tighter engagement between the fastener and the corresponding fastener ring, thereby improving the firmness of the fastening between the control unit and the heat diffusion plate.

[0039] Preferably, one or more fastener seats are not mounting bosses for screws. Preferably, the aperture of each fastener seat does not have threads for screws. The aperture may be smooth. This may allow one or more fasteners to fit more easily within the corresponding fastener seat.

[0040] In some embodiments, one or more fastener seats define a channel for a corresponding fastener. The channel may extend in a direction substantially parallel to the plane of the heat diffusion plate. As described above, the channel may extend from an aperture defined by the fastener seat. The channel may define a hole, which may be a through hole or a blind hole.

[0041] In some embodiments, a plurality of fastener seats are provided. In such embodiments, preferably, at least two of the fastener seats are parallel to each other. As described above, this facilitates mounting the control unit to the heat diffuser plate. In such embodiments, preferably, at least two of the channels of the fastener seats are parallel to each other. Preferably, at least two of the apertures defined by the respective fastener seats are located in the same plane. This may further improve the ease with which the control unit can be mounted to the heat diffuser plate.

[0042] Each fastener seat may include a vertical section and a horizontal section. The vertical section is preferably arranged to prevent lateral movement of the corresponding fastener relative to the plane of the heat diffusion plate, except for the direction in which the fastener is manipulated to cooperate with the corresponding fastener seat. The horizontal section is preferably arranged to prevent vertical (e.g., downward) movement of the corresponding fastener away from the heat diffusion plate, i.e., relative to the plane of the heat diffusion plate. This can help prevent the weight of the control unit from causing one or more fasteners and one or more corresponding fastener seats to disengage from each other, such as to trip.

[0043] Preferably, the screwless fastener is arranged to be held by the horizontal segment between the horizontal segment and the heat diffuser when the control unit is mounted to the heat diffuser. The horizontal segment is preferably arranged in a plane parallel to but offset (e.g. vertically) from the plane of the heat diffuser. This may allow the horizontal segment to clamp the fastener between the horizontal segment and the heat diffuser while facilitating the fit between the fastener and the fastener seat.

[0044] The fastener seat may include a pair of vertical segments connected by a horizontal segment so that the fastener seat is generally in the shape of an "O" or "U." Providing a pair of vertical segments can prevent lateral movement of the fastener in two opposite directions when positioned between the vertical segments.

[0045] Each fastener seat may define a void shaped to correspond to the "U" shape of the fastener such that the fastener is snugly received within the void.

[0046] In some embodiments, one or more screwless fasteners are loops. In some embodiments that may overlap, one or more fastener seats are tabs. In other words, although one or more fasteners and one or more fastener seats can be matched by the fastener being received in a corresponding fastener seat, in some embodiments, one or more fastener seats are received in a corresponding fastener. It should be understood that both arrangements of fastener / fastener seat pairs provide screwless fastening between the control unit and the heat diffusion plate. Therefore, in some embodiments, the features of the fasteners described herein can and preferably are applied to the fastener seats, and vice versa.

[0047] In some embodiments, in addition to one or more screwless fasteners, the control unit also defines an aperture for receiving a screw. For example, the mounting component may include an aperture for receiving a screw. In some embodiments, in addition to one or more corresponding fastener seats, the heat diffusion plate may also include a threaded hole for receiving a screw. When the control unit is fastened to the bottom side of the heat diffusion plate by screwless fastening of one or more screwless fasteners and fastener seats, the aperture and threaded hole can be arranged to align. This can allow a screw to be inserted into the threaded hole through the aperture of the control unit, thereby providing an additional means of fixing the control unit to the heat diffusion plate.

[0048] It will be appreciated that due to the screwless fastening provided by the one or more screwless fasteners and the one or more fastener seats, the number of screws used to secure the control unit to the heat diffuser plate can be reduced. In some embodiments, screws may not be used at all. As described above, reducing the number of screws used to fasten the control unit to the heat diffuser plate can reduce the cost and complexity of manufacturing the appliance, particularly the control unit and / or the heat diffuser plate of the appliance.

[0049] The threaded hole may be defined by a boss arranged on the bottom side of the heat diffusion plate. The aperture may be defined by a mounting component of the control unit. The aperture may be provided on a side of the mounting component opposite to one or more fasteners (e.g., the opposite side of the bottom side of the heat diffusion plate, rather than the opposite surface of the heat diffusion plate). This may allow one side of the control unit to be held in a stationary position by a screw-removing fastening provided by one or more fasteners and corresponding fastener seats, and then the other side of the control unit to be fixed in place by inserting a screw through the aperture of the mounting component into the threaded hole. This helps to securely mount the control unit to the heat diffusion plate.

[0050] The applicant has determined that when the control unit is being mounted to the heat diffuser plate, the thermally sensitive actuator may strike the underside of the heat diffuser plate, which may result in damage to the heat diffuser plate and / or the thermally sensitive actuator.

[0051] In some embodiments, the thermal actuator comprises one or more protrusions. The protrusions may be present as a result of the method of manufacturing the thermal actuator. In some embodiments, there may be a risk that one or more protrusions may scratch the underside of the heat diffuser plate during mounting of the control unit to the heat diffuser plate.

[0052] Therefore, in some embodiments described herein, the bottom side of the heat diffusion plate defines one or more grooves arranged to receive corresponding parts of the thermal actuator. The corresponding parts of the thermal actuator may be protrusions. This may allow the control unit to be mounted on the heat diffusion plate without damaging the heat diffusion plate and / or the thermal actuator.

[0053] The recess may be arranged to receive a corresponding component of the thermal actuator during at least a portion of the time that the screwless fastener is mated with one or more corresponding fastener seats. For example, the recess may be arranged to receive a corresponding component of the thermal actuator when the one or more screwless fasteners are being inserted into the corresponding fastener seats at a certain angle. Preferably, the heat diffusion plate defines a pair of recesses for receiving a corresponding pair of protrusions on the thermal actuator.

[0054] In some embodiments, the control unit can be mounted to the underside of the heat diffusion plate by moving the control unit toward the heat diffusion plate at an oblique angle (e.g., less than 90°) relative to the plane of the heat diffusion plate to cause one or more screwless fasteners to mate with one or more corresponding fastener seats. The control unit can then be pivoted about the mating screwless fasteners and fastener seats to bring the thermal actuator into contact with the heat diffusion plate. Applicants have recognized that during installation of the control unit in this manner, one or more recesses in the heat diffusion plate discussed above can be particularly advantageous for reducing the risk of damage to the heat diffusion plate and / or the thermal actuator.

[0055] When viewed from another aspect, the utility model provides a liquid heating device, comprising:

[0056] Liquid heating containers;

[0057] an electric heater comprising a heat diffuser plate defining one or more fastener seats and arranged to heat a base of the liquid heating vessel; and

[0058] A control unit, as described herein, is mounted to the underside of a heat diffusion plate, wherein each of the one or more screwless fasteners of the control unit cooperates within a corresponding fastener seat of the one or more fastener seats of the heat diffusion plate to provide a screwless fastening between the control unit and the heat diffusion plate.

[0059] As described above, in some embodiments, the mounting plate includes apertures for receiving screws, and the heat diffusion plate includes threaded holes for receiving screws. In such embodiments, in addition to the screws that secure the control unit to the heat diffusion plate, the device may also include at least one (preferably at least two) screwless fastenings.

[0060] The liquid heating vessel may be of any suitable or desired shape, defining a volume for receiving a liquid to be heated. Preferably, the liquid heating vessel is capable of safely containing liquid, particularly water, when heated to boiling. The liquid heating vessel may be made of any suitable or desired material. Preferably, the liquid heating vessel is made of stainless steel, such as food safe grade stainless steel.

[0061] The electric heater preferably comprises an electric heating element. The electric heating element is preferably an electric heating element with a sheath. The heat diffusion plate is preferably arranged under the base of the liquid heating container. The electric heating element can be mounted to the bottom side of the heat diffusion plate.

[0062] As mentioned above, the liquid heating appliance may comprise a cordless electrical adapter part for mating with a corresponding base electrical connector part.Preferably, the control unit comprises a cordless electrical adapter part arranged to mating with a corresponding base electrical connector part.

[0063] When viewed from another side, the utility model provides a heat diffusion plate for being installed in thermal communication with a heating element of a liquid heating device, the heat diffusion plate comprising one or more fastener seats arranged to cooperate with one or more corresponding screwless fasteners of a control unit for mounting the control unit to the bottom side of the heat diffusion plate to provide a threadless fastening between the heat diffusion plate and the control unit; each of the one or more fastener seats comprises a cutout, wherein the cutout is a baffle folded out of the plane of the heat diffusion plate.

[0064] Those skilled in the art will appreciate that many variations and modifications may be made to the above-described embodiments within the scope of the various aspects and embodiments of the invention set forth herein. Any aspect of the invention described herein may (and preferably) include one or more (e.g., all) of the optional and preferred features outlined herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Certain preferred embodiments of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which:

[0066] Figure 1 shows a perspective view of a liquid heating appliance according to an embodiment of the present invention;

[0067] Figure 2 Shows Figure 1A perspective view of a heating device of an appliance, comprising a control unit according to an embodiment of the present invention;

[0068] Figure 3 Shows Figure 2 An exploded view of the heating device;

[0069] Figure 4 Shows Figure 2 a perspective view of a control unit; and

[0070] Figure 5 A perspective view of a control unit according to another embodiment of the present invention is shown. DETAILED DESCRIPTION

[0071] Figure 1 A perspective view of a liquid heating appliance 2 (hereinafter referred to as appliance 2) according to one embodiment of the present invention is shown. The appliance 2 comprises a liquid heating vessel 4, a vessel mouth 6 and a handle 8. The top of the appliance 2 is closed with a lid 10. The appliance 2 is arranged to rest on a power base 12 having a centrally arranged 360-degree base electrical connector part 14 for powering the appliance 2.

[0072] The apparatus 2 also includes an electric heater ( Figure 1 ), for heating a certain volume of liquid contained in a liquid heating container 4.

[0073] Figure 2 and Figure 3 They are shown separately Figure 1 1 and 2 show a perspective view and an exploded view of an electric heater 18, a control unit 16 and a base 23 of a liquid heating container 4 of an appliance 2. For the sake of clarity, other components of the appliance 2 have been removed. The control unit 16 and the heater 18 are both mounted below the base 23 of the liquid heating container 4.

[0074] The control unit 16 is arranged to receive the base electrical connector part 14 of the power base 12 and control the supply of power from the power base 12 to the electric heater 18. When electrical energy is supplied to the heater 18, the heater 18 transfers heat to the base 23 of the liquid heating container 4, thereby heating the contents of the liquid heating container 4.

[0075] like Figure 3 As shown in the exploded view of FIG. 1 , the heater 18 includes a sheathed electric heating element 18a and a circular heat diffusion plate 18b. The heating element 18a is a conventional "horseshoe" structure with electrical terminals 19 at both ends. The heating element 18a extends substantially around the circumference of the bottom side of the diffusion plate 18b. The control unit 16 is arranged to be mounted in the center of the bottom side of the diffusion plate 18b.

[0076] The diffuser plate 18b includes a first fastener seat 20a and a second fastener seat 20b, both of which extend vertically downward from the bottom side of the diffuser plate 18b. In this embodiment, the fastener seats 20a, 20b are flaps that are folded out of the plane of the diffuser plate 18b. Each of the flaps 20a, 20b includes an aperture and thus defines a loop. As will be described in more detail below, the loops 20a, 20b are shaped to receive corresponding fastener tabs ( Figure 2 and Figure 3 The respective apertures defined by the rings 20a, 20b are substantially located in the same plane as each other, and the rings 20a and 20b are symmetrically located on either side of the central axis of the circular diffuser plate 18b.

[0077] In this embodiment, the collars 20a, 20b are located on the side of the diffuser plate 18b opposite the electrical terminals 19 of the electrical heating element 18a.

[0078] The circular diffuser plate 18b also includes a threaded boss 24 for receiving a screw. The boss 24 extends vertically downward from the bottom side of the diffuser plate 18b.

[0079] The bottom side of the diffuser plate 18b defines a first pair of grooves 21a and a second pair of grooves 21b. The first pair of grooves 21a is arranged adjacent to the first circle 20a, while the second pair of grooves 21b is arranged adjacent to the second circle 20b.

[0080] Figure 4 Shows Figure 2 and Figure 3 A perspective view of the control unit 16 is shown.

[0081] The control unit 16 comprises a molded plastic control body 26, on the bottom side of which a cordless power adapter part 28 is formed. The cordless power adapter part 28 is a 3-pole adapter part including a ground pin, a live ring and a neutral ring (not shown). The base electrical connector part 14 comprises a central aperture for receiving the ground pin and a coaxial annular aperture for receiving the live ring and the neutral ring. The electrical contacts accommodated in the central aperture and the coaxial aperture contact the live ring and the neutral ring conductors, respectively, to connect the live pole and the neutral pole of the power circuit when the connector part 14 / adapter part 28 are connected together.

[0082] The control unit 16 also includes a fixed electrical tab 29 that is electrically connected to an electrical contact in the power circuit. As known in the art, flying leads or other electrical connections may be used for the fixed electrical tab 29 to connect the power circuit to the electrical terminals 19 of the heater 18.

[0083] The control unit 16 includes a mounting member in the form of a mounting plate 32, in this example a metal mounting plate 32 attached to the molded plastic control body 26. One suitable form of attachment is described in WO2017 / 158321, the contents of which are incorporated herein by reference.

[0084] The control unit 16 also includes a first thermally sensitive actuator 30a and a second thermally sensitive actuator 30b, supported by a metal mounting plate 32 on the top side of the control body 26. The thermally sensitive actuators 30a, 30b are snap-acting bimetallic actuators, each set to operate independently at an overheat temperature. The arrangement of the thermally sensitive actuators 30a, 30b causes a switch (not shown) within the control unit 16 to open, thereby interrupting the power supply to the heater 18. As is known in the art, this allows the heater 18 to be cut off in the event of a "dry boil" in which there is no liquid in the liquid heating vessel 4.

[0085] The actuators 30a, 30b are located on the top surface of the control unit 16 so that when the control unit 16 is mounted to the bottom side of the diffuser plate 18b, the actuators 30a, 30b are in thermal communication with the diffuser plate 18b. This means that the actuators 30a, 30b are arranged to detect the temperature of the diffuser plate 18b.

[0086] The metal mounting plate 32 of the control unit 16 defines a first fastener tab 22a and a second fastener tab 22b, both of which protrude from the edge of the mounting plate 32 in the same plane as the mounting plate 32 to provide a pair of fastener tabs 22a, 22b. Each of the tabs 22a, 22b is arranged to be received in a corresponding one of the fastener seats (rings) 20a, 20b provided on the bottom side of the diffuser plate 18b. The tabs 22a, 22b protrude from the mounting plate 32 so that they are substantially parallel to each other. The tabs 22a, 22b are slot-shaped and have a U-shaped cross-section in a plane perpendicular to the plane of the metal plate 32.

[0087] The first tab 22a is arranged adjacent to the first thermal actuator 30a, while the second tab 22b is arranged adjacent to the second thermal actuator 30b. This helps to ensure that when the control unit 16 is mounted to the diffuser plate 18b, the thermal actuators 30a, 30b are pressed to the bottom side of the diffuser plate 18b with a force sufficient to ensure that thermal energy is adequately transferred from the diffuser plate 18b to the thermal actuators 30a, 30b, thereby improving the reliability of the actuators 30a, 30b operating at the desired overheat temperature.

[0088] The metal mounting plate 32 also defines apertures 34 for receiving screws (not shown). The apertures 34 are positioned so that when the control unit 16 is mounted on the diffuser plate 18b, the apertures 34 are aligned with the threaded bosses 24. This allows the control unit 16 to be screwed to the underside of the diffuser plate 18b once the control unit 16 is positioned using the hoops 20a, 20b and fastener tabs 22a, 22b, as will be described in more detail below.

[0089] The control unit 16 can be mounted to the underside of the diffuser plate 18b by moving the control unit 16 relative to the diffuser plate 18b in a direction substantially parallel to the plane of the diffuser plate 18b until the fastener tabs 22a, 22b are received in the respective loops 20a, 20b. The engagement between the fastener tabs 22a, 22b and the loops 20a, 20b provides a stop for the control unit 16 for fixing its position and orientation relative to the diffuser plate 18b. The unit 16 can then be secured in place by inserting a screw (not shown) through the aperture 34 in the control unit 16 and into the threaded boss 24 of the diffuser plate 18b.

[0090] Applicants have recognized that when the control unit 16 is being mounted to the diffuser plate 18b, the thermal actuators 30a, 30b may hit the bottom side of the diffuser plate 18b. In particular, the thermal actuators 30a, 30b each include a pair of protrusions 31a, 31b, which are formed as a result of the manufacturing process, which may scratch the bottom side of the diffuser plate 18b. This may cause damage to the diffuser plate 18b and / or the thermal actuators 30a, 30b.

[0091] Thus, as described above, the bottom side of the diffuser plate 18b defines a first pair of recesses 21a and a second pair of recesses 21b that are shaped to receive a corresponding pair of protrusions 31a, 31b in the first and second thermal actuators 30a, 30b. This allows the control unit 16 to be mounted to the diffuser plate 18b without causing damage to the diffuser plate 18b and / or the thermal actuators 30a, 30b.

[0092] Figure 5 A perspective view of a control unit 116 according to another embodiment of the present invention is shown.

[0093] The control unit 116 and Figure 2 The control unit 16 of FIG. 1 is substantially the same except that the control unit 116 further includes a trip bar 136 that is manually operable to open and close electrical contacts in the power circuit. Figure 5 The control unit 116 in Figures 2 to 4The control unit 16 shown in FIG. 1 is mounted to the heat diffuser plate in a similar manner to that shown in FIG. 1 , i.e., by engaging fastener tabs 122a, 122b with corresponding fastener seats (e.g., rings) in a heat diffuser plate (not shown) and inserting screws through apertures 134 to engage threaded holes in the heat diffuser plate.

[0094] However, in embodiments where the control unit 116 includes a trip bar 136, a fastener seat (e.g., a ring) of the diffuser plate can be arranged on the other side of the thermal diffuser plate (i.e., closer to the electrical terminals of the heating element) to leave room for the trip bar 136 when the control unit 116 is in place on the bottom side of the diffuser plate.

[0095] The trip bar 136 extends from under the mounting plate 132 of the control unit 116 in the same direction from the same side of the control unit 116 as the fastener tabs 122a, 122b. The aperture 134 for receiving the screw is arranged on the side of the control unit 116 opposite the trip bar 136. Therefore, due to the arrangement and positioning of the fastener tabs 122a, 122b, it is not necessary to use a screwdriver near the trip bar 136 in order to mount the control unit 116 to the heat diffusion plate. Instead, the screwdriver only needs to be operated on the other side of the control unit 116. This can reduce the risk of the trip bar 136 being damaged by the screwdriver during assembly of the appliance, and can allow the trip bar 136 to be designed without being restricted by a cutout for providing access for the screwdriver.

Claims

1. A control unit for mounting to the bottom side of a heat diffusion plate of an electric heater of a liquid heating appliance, characterized in that The control unit comprises: a switch for controlling the supply of power to the electric heater; a bimetallic element operable at a predetermined temperature to open the switch to interrupt the supply of power to the electric heater; and a mounting plate extending in a substantially horizontal plane, the mounting plate including one or more screwless fasteners arranged to cooperate with one or more corresponding fastener seats in the heat diffuser plate to provide a screwless fastening between the control unit and the heat diffuser plate when the mounting plate is mounted to an underside of the heat diffuser plate; Wherein, each of the one or more screwless fasteners defines a "U" shaped slot, the "U" shaped slot comprising a "U" shape defined in a plane substantially perpendicular to a horizontal plane of the mounting plate.

2. The control unit according to claim 1, wherein: The one or more screwless fasteners and the one or more fastener seats are arranged to cooperate such that the one or more screwless fasteners are received within the one or more corresponding fastener seats.

3. The control unit according to claim 1 or 2, wherein: The one or more screwless fasteners are disposed on an upper surface of the control unit.

4. The control unit according to claim 1 or 2, wherein: The one or more screwless fasteners are mechanical tabs.

5. The control unit according to claim 4, wherein: The tabs do not include apertures for receiving screws.

6. The control unit according to claim 1 or 2, wherein: The one or more screwless fasteners project laterally from the mounting plate.

7. The control unit according to claim 1 or 2, wherein: The one or more screwless fasteners are arranged such that when the control unit is mounted to the heat diffuser plate, the screwless fasteners and the heat diffuser plate are substantially parallel.

8. The control unit according to claim 1 or 2, wherein: The one or more screwless fasteners project from the mounting plate in a plane that is below the horizontal plane of the mounting plate.

9. The control unit according to claim 1 or 2, wherein: The control unit includes a plurality of screwless fasteners, wherein at least two of the plurality of screwless fasteners are parallel to each other.

10. The control unit according to claim 1 or 2, wherein: The mounting plate also includes apertures for receiving screws.

11. The control unit according to claim 10, wherein: The aperture is disposed on a side of the mounting plate opposite the one or more screwless fasteners.

12. The control unit according to claim 1 or 2, wherein: The control unit further comprises a cordless electrical adapter part arranged to mate with a corresponding base electrical connector part.

13. A liquid heating device, characterized in that: The liquid heating device comprises: Liquid heating containers; an electric heater comprising a heat diffuser plate and arranged to heat a base of the liquid heating vessel, wherein the heat diffuser plate defines one or more fastener seats; and The control unit according to claim 1 or 2, wherein the control unit is mounted to the bottom side of the heat diffusion plate; Each of the one or more screwless fasteners of the control unit cooperates within a corresponding fastener seat of the one or more fastener seats of the heat diffuser plate to provide a screwless fastening between the control unit and the heat diffuser plate.

14. The liquid heating device according to claim 13, wherein: The mounting plate of the control unit further includes apertures for receiving screws, and the heat diffusion plate includes threaded holes for receiving screws, wherein the apertures and threaded holes are aligned and the screws pass through the apertures and threaded holes to additionally secure the control unit to the heat diffusion plate.

15. The liquid heating device according to claim 13, wherein: The bottom side of the heat diffuser plate defines one or more recesses arranged to receive corresponding protrusions of the bimetallic element during at least a portion of the time when the screwless fastener is mated with the one or more corresponding fastener seats.

16. A heat diffusion plate, used for an electric heater of a liquid heating device, characterized in that: The heat diffuser plate comprises one or more fastener seats arranged to cooperate with one or more corresponding screwless fasteners of a control unit for mounting the control unit to an underside of the heat diffuser plate to provide a screwless fastening between the control unit and the heat diffuser plate; Wherein, each of the one or more fastener mounts includes a cutout, wherein the cutout is a flap folded out of the plane of the heat diffuser plate.

17. The heat diffusion plate according to claim 16, wherein: The baffle has a first edge connected to the heat diffusion plate and a free edge, the baffle including an aperture between the first edge and the free edge.

18. The heat diffusion plate according to claim 16 or 17, wherein: The one or more fastener seats define an aperture for receiving a corresponding one of the one or more screwless fasteners, and wherein an angle between a plane of the aperture and a plane of the heat diffuser plate is greater than zero.

19. The heat diffusion plate according to claim 18, wherein: The aperture of each fastener seat has a width substantially equal to a width of a corresponding screwless fastener arranged to mate with the fastener seat.

20. The heat diffuser plate according to claim 18, wherein The aperture of each fastener seat has a height substantially equal to the height of a corresponding screwless fastener arranged to mate with the fastener seat.

21. The heat diffusion plate according to claim 16 or 17, wherein: Each fastener holder includes: a vertical segment arranged to prevent lateral movement of the corresponding screwless fastener relative to the plane of the heat diffuser plate, except for the orientation of the screwless fastener to mate with the corresponding fastener seat; and A horizontal segment is arranged to prevent vertical movement of the corresponding screwless fastener away from the heat diffuser plate.

22. A liquid heating device, characterized in that: The liquid heating device comprises: Liquid heating containers; an electric heater comprising a heat diffuser plate as claimed in claim 16 or 17, wherein the electric heater is arranged to heat a base of the liquid heating vessel; and a control unit mounted to the bottom side of the heat diffusion plate, wherein the control unit comprises: a switch for controlling the supply of power to the electric heater; a bimetallic element operable at a predetermined temperature to open the switch to interrupt the supply of power to the electric heater; and A mounting plate includes one or more screwless fasteners arranged to cooperate with corresponding ones of the one or more fastener seats of the heat diffuser plate to provide screwless fastening between the control unit and the heat diffuser plate.

23. The liquid heating device according to claim 22, wherein: The mounting plate of the control unit further includes apertures for receiving screws, and the heat diffusion plate includes threaded holes for receiving screws, wherein the apertures and threaded holes are aligned and the screws pass through the apertures and threaded holes to additionally secure the control unit to the heat diffusion plate.

24. The liquid heating device according to claim 22, wherein: The bottom side of the heat diffuser plate defines one or more recesses arranged to receive corresponding protrusions of the bimetallic element during at least a portion of the time when the screwless fastener is mated with the one or more corresponding fastener seats.

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