FORM 2
THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003
COMPLETE SPECIFICATION (See section 10, rule 13) 1. Title of the invention: HEATING ASSEMBLY
2. Applicant(s)
NAME NATIONALITY ADDRESS
BAJAJ ELECTRICALS LTD Indian 45/47, Veer Nariman Road, Mumbai,
Maharashtra 400 001, India
COUNCIL OF SCIENTIFIC Indian Anusandhan Bhawan, Rafi Marg,
& INDUSTRIAL New Delhi -110001, India
RESEARCH

TECHNICAL FIELD [001] The present subject matter relates in general to heating devices and in particular, to an electromagnetic induction electric iron.
BACKGROUND [002] An electromagnetic induction heating device works on the principle of generating heat due to eddy currents induced in the heating devices. In such heating devices, a metal plate of the heating device is placed in an electromagnetic field such that eddy currents are induced in the metal plate. The induced eddy currents generate heat in the metal plate. For example, an electromagnetic induction electric iron is an electrical appliance used for ironing of clothes. The electromagnetic induction electric iron uses magnetic flux for heating the metal sole plate through eddy current. The electromagnetic induction iron, when heated, is then moved over clothes for ironing purpose. The electromagnetic induction electric iron is referred to as induction iron, hereafter, for the sake of convenience in readability.
[003] For heating of the metal plate of the induction heating devices, such as a sole plate of the induction iron, the induction iron is placed over a heating platform which emits rapidly alternating electromagnetic waves. The electromagnetic waves penetrate the metal sole plate which induces eddy currents in the metal sole plate of the iron. The induced eddy current causes the heating of the metal sole plate of the induction iron. When the sole plate is heated to a desired temperature, a user lifts the induction iron from the heating platform and thereafter irons his clothes. It is to be noted that while the user is ironing the clothes, the metal sole plate is not being energized, i.e., it is not being heated (as it is removed from the heating platform which heats up the sole plate). Thus, during ironing of the clothes, the metal sole plate tends to lose heat rapidly. [004] Generally, induction irons do not include any mechanism to compensate for the heat loss, thus, the efficiency of such induction iron is low. Consequently, such

induction irons consume more electric power. Further, due to low heat retention capacity of the metal sole plate, the user has to frequently put the induction iron on the heating platform which causes further inconvenience to the user.
BRIEF DESCRIPTION OF DRAWINGS [005] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digits of a reference number identify the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference, like features and components.
[006] Figure 1a and 1b illustrate a heating assembly in accordance with an example of the present subject matter;
[007] Figure 2a illustrates an example of a holding element according to an example implementation of the present subject matter.
[008] Figure 2b shows a cross section of the heating assembly having a plurality of reservoirs 204 in accordance with an example of the present subject matter; [009] Figure 3a shows an induction iron according to an example implementation of the present subject matter.
[0010] Figure 3b shows an induction iron according to another example implementation of the present subject matter.
DETAILED DESCRIPTION [0011] The present subject matter provides a heating assembly which has improved heat retention capability and can be used in an electromagnetic heating device, such as an induction iron. The heating assembly of the present subject matter comprises a metal plate which is heated by electromagnetic induction. Further, according to the present subject matter, the heating assembly comprises holding elements to hold a heat retaining substance. The heat retaining substance retains the heat generated in the metal plate and thereby compensates for the rapid loss of the heat during usage of the heating

assembly, such as ironing of the clothes when the heating assembly is used in the induction iron.
[0012] Thus, the heat retaining substance compensates for the heat loss that occurs during use of an electrical appliance having the heating assembly of the present subject matter. This maintains the metal sole plate temperature much better than the conventional irons as well as enhances the user experience.
[0013] Although the subject matter has been explained in the context of figures that depict an (electromagnetic induction) induction iron, it will be understood that the subject matter may be extended to any electromagnetic induction heating device which works on the principle of electromagnetic heating.
[0014] Aspects of the present subject matter related to heating assembly for an electromagnetic induction iron will now be described in detail in conjunction with the following figures. It should be noted that the description and figures merely illustrate the principles of the present subject matter along with examples described herein and should not be construed as a limitation to the present subject matter. It is thus understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and specific examples thereof, are intended to encompass equivalents thereof.
[0015] Figure 1a shows a heating assembly 100. The heating assembly 100 comprises a metal plate 102. A side view of the heating assembly 100 is shown in figure 1b. The metal plate 102 is heated by electromagnetic radiations. The electromagnetic radiation may be generated by some other device (not shown) which may lie in vicinity of the of heating assembly 100. The heating assembly 100 comprises a plurality of holding elements 104 which holds heat retaining substance 106.
[0016] When the metal plate 102 is heated due to electromagnetic induction, the heat retaining substance 106 contained by the holding element 104 is also heated. The heat retaining substance 106 has a property of retaining the heat for a longer period of time

as compared to a time period for which the metal plate 102 retains heat or any conventional metal plate retains heat. While the heating assembly 100 is being used, the heat is dissipated from the metal plate 102. As the heat retaining time of the heat retaining substance 106 is longer, the heat retaining substance 106 transfers the heat to the metal plate 102 through conduction while heat is dissipated from the metal plate 102. Thus, due to transfer of heat from the heat retaining substance 106 to the metal plate 102, the metal plate 102 remains heated (at a particular temperature) for a longer period of time compared to a period of time for which the metal plate 102 would have remain heated (at the particular temperature), had the heat retaining substance 106 not been present on the metal plate 102 or when compared to the conventional systems. [0017] Figure 2aillustrates a holding element according to an example implementation of the present subject matter. Figure 2a shows a heating assembly 200, similar to heating assembly 100, with a metal plate 202. A plurality of reservoirs 204 serves as holding elements for the heating assembly 200. The plurality of reservoirs 204 may have a depth in range of 2-4 millimeters (mm). Heat retaining substance 206 is contained in the plurality of reservoirs 204. In other words, the plurality of reservoirs 204 are filled with the heat retaining substance.
[0018] In an example, the reservoirs 204 may be inbuilt in the metal plate 202 and a retention plate may be placed over the metal plate 202 such that the retention plate covers the plurality of reservoirs 204. When the metal plate 202 is heated, the heat retaining substance 206 is also heated and attains the same temperature as that of the metal plate 202. When the heating assembly 200 is being used, the heat is dissipated from the metal plate 202 and the temperature of the metal plate 202 drops. As the heat retaining capacity of the heat retaining substance 206 is more, the temperature of the heat retaining substance 206 drops at a rate which slower than a rate of drop of temperature of the metal plate 202. Thus, a temperature difference exits between the metal plate 202 and the heat retaining substance 206 due to which heat transfer occurs between the heat retaining substance 206 and the metal plate 202 as shown by arrows

208. Due to the heat transfer from the heat retaining substance 206 to the metal plate 202, the metal plate 202 is maintained at a particular temperature for a longer period of time.
[0019] In an example, the heat retaining substance 206 may be aluminum oxide powder, magnesium oxide powder, cenosphere, silicon oxide powder. Further, in an example, the heat retaining substance 206 may be in powdered form, pellets form, granules form etc. Further, a circular shape of the plurality of reservoirs 204 is shown only for the representational purposes and various example implementations, the shape of the plurality of reservoirs 204 may be a rectangle, square, pentagonal and any other similar shape. Further, the metal may be any ferrous metal or an alloy of metal having ferrous characteristics, i.e., containing iron.
[0020] Figure 2b shows a cross section of the heating assembly 200. The heating assembly comprises a metal plate 202 which further comprises the plurality of reservoirs 204. The cross section is shown along the line AA'. In an example, a retaining plate 210 is kept over the plurality of reservoirs 206 to enable the heat retaining substance to be held firmly in the plurality of reservoirs 204. In the figure, two surfaces 202a and 202b of the metal plate 202 are shown. The retaining plate 210 lies on the surface 202b while the surface 202a comes in contact with the clothes while ironing.
[0021] In an example, a body of an electric appliance, such as an induction iron is coupled with the retention plate 210. Thus, the retention plate 210, in addition to holding the heat retaining substance 206 within the plurality of reservoirs 204 also provides a platform for coupling the body of an electric appliance to which the heating assembly 200 is to be fitted.
[0022] In an example, a depth 212 of the heating assembly may be in range of 3-6 mm and a thickness 214 of the metal plate may be in range of 8-10 mm. Further, in another example, the plurality of reservoirs 204 may be like through holes through the metal plate 202. In such cases, two retention plates may be used on both sides of the metal

plate 202 to allow the heat retaining substance 206 to be retained within the metal plate 202.
[0023] Figure 3a shows an induction iron 300 according to an example implementation of the present subject matter. According to the present subject matter, the induction iron 300 of the present subject matter comprises a housing unit 302 to which a heating assembly 304 is coupled. The heating assembly 304 comprises a metal plate 306. The metal plate 306 is ferrous in nature and receives electromagnetic radiations which heats up the metal plate 306. For example, the induction iron 300 may be kept in an electromagnetic field (explained in figure 3b) such that the metal plate 306 lies under the influence of the electromagnetic field.
[0024] The induction iron 300 further comprises a plurality of holding elements 308 on the metal plate 306 to hold heat retaining substance 310. In the figure, the plurality of holding elements 308 are shown with dotted lines as the plurality of holding elements lies on inner side of the metal plate 306. In an example, the holding element 308 may be a reservoir, a groove, an irregularity in the metal plate 306 which may hold the heat retaining substance 310. When the metal plate 306 is heated, the heat retaining substance 310 also heats up due to heat transfer between the metal plate 306 and the heat retaining substance 310. The heat retaining substance 310 retains heat for more time as compared to the time for which the metal plate 306 retains heat. Thus, while using the induction iron 300, the heat retaining substance 310 compensates for the amount of heat lost by the metal plate 306 and maintains the metal plate 306 at a particular temperature for a longer period of time. In an example, the holding element 302 comprise a handle 312 which may be used by a user to hold the induction iron 300. [0025] In an example, the plurality of holding elements 308 may be plurality of reservoirs 308-1similar to the reservoirs as shown in the figure 2a and figure 2b. In other words, the heating assembly 200, having a plurality of reservoirs 204, may be coupled with the induction iron 300. The plurality of reservoirs 204 may contain heat retaining substance which retains the heat for a longer period of time and transfers the

heat to the metal plate 306 to maintain the temperature of the metal plate for a longer period of time. Similarly, in an example, the heating assembly 300 may also be used with the induction iron 300. In such cases, the metal plate 306 may contain irregularity which hold the heat retaining substance. For example, the metal plate 306 may comprise irregularity or uneven surfaces such that the heat retaining substance may be coated over the metal plate.
[0026] In an example, the housing unit 302 may be made up of non-conductive material, such as plastic, fiber, fiberglass, rubber etc. Further, in an example, the metal plate 306 may be made up of ferrous metal, ferrous alloys. The housing unit 302 may be attached to a retaining plate (not shown) kept over the metal plate 306 (as described with respect to figure 2b). The retaining plate may also hold the heat retaining substance (310) within the plurality of holding elements (308). The heat retaining substance 310 may be metal oxides, silicon oxide powder, cenosphere etc. [0027] Figure 3b shows an induction iron having 300 in another example of the present subject matter. Figure 3b further shows a device 314 which generates electromagnetic radiation for heating of the metal plate 306 of the induction iron 300. The device 314 may have a platform 316 and an enclosure 318. The induction iron 300 may be kept on the platform 316, such that the metal plate 306 is in contact with the platform 316. A stopper 320 may stop the induction iron 300 from sliding down the platform 316. [0028] The enclosure 318 may have an electronic assembly, such as solenoidal coils for generating electromagnetic fields. When a user intends to use the induction iron 300, the user inserts in a plug 322 into a socket and puts the induction iron on the platform 316 with the metal plate 306 lying on the platform 316. As soon as the user inserts the plug 322 into the socket, an electric current excites the electric assembly of the device 314 and an electromagnetic field is established around the device 314. As the induction iron 300 lies on the platform 316, the metal plate 306 of the induction iron also comes into effect of the generated electromagnetic field.

[0029] The electromagnetic field induces eddy currents in the metal plate 306 which heats up the metal plate 306. The induction iron is kept on the platform 316 till a desired temperature of induction iron 300 is achieved. In an example, the induction iron 300 may have a temperature sensor which may measure the temperature of the metal plate 306 and the same may be indicated to the user. In an example, types of clothes that could be ironed at the corresponding temperature may also be indicated. When the metal plate 306 of the induction iron 300 is heated to a desired temperature, the user may remove the induction iron 300 from the platform 316 and may iron his clothes. When the temperature of the metal plate 306 of the induction iron 300 falls below a threshold temperature, the user may again put the induction iron 300 on the platform 316 for metal plate 306 to get heated.
[0030] Further, in another example, there may be automatic cut-off system with the device 314 which may prevent the induction iron 300 from heating beyond a desired temperature corresponding to a type of cloth that the user desires to iron. For example, a user may rotate a knob 324 to indicate a type of clothing he desires to iron. A temperature measuring sensor may also be coupled with the platform 316 which may be in contact with the metal plate 306 when the induction iron 300 is placed on the platform 316. The temperature measuring sensor may measure the temperature of the metal plate 306 and may indicate the same to the metal plate 306. According to the type of clothes selected by the user, by rotating the knob 324, the device may cut-off the supply when a desired temperature for that the selected clothing is received provided that the user has not removed the iron 300.The device 314 may switch ON the supply when the temperature of the metal plate 306 falls below a particular threshold temperature. For example, in the figure 3b, the knob is pointed at the 'silk'. Silk should be ironed at 148 °C/300 °F. Thus, when temperature of the metal plate 306 reaches 148 °C/300 °F, the device 314 may cut-off the supply and when the temperature of the metal plate 306 falls below a threshold temperature, say 125 °C/257 °F, the device 314 may switch ON the power supply. Further, in an example, the device 314 may cut-off

the supply when the iron 300 is not on the platform 316. This helps in saving electric
power.
[0031] Although implementations for an electromagnetic induction iron are described,
it is to be understood that the present subject matter is not necessarily limited to the
specific features of the systems described herein. Rather, the specific features are
disclosed as implementations for the electromagnetic induction iron.

I/We Claim:
1. A heating assembly (100) comprising:
a metal plate (102), wherein the metal plate (102) is to be heated by electromagnetic induction, the metal plate (102) comprising:
holding elements (104) provided on the metal plate (102) to hold a heat retaining substance (106) which retains heat for a longer period of time as compared to a period of time for which the metal plate (102) retains heat., wherein the holding elements (104) are a plurality of reservoirs (204) in the metal plate (102), and wherein the heat retaining substance (106) is contained in the plurality of reservoirs (204).
2. The heating assembly (100) as claimed in claim 1, wherein the heat retaining substance (106) is contained in the plurality of reservoirs (204) in the form of at least one of pallets, powder, granules.
3. The heating assembly (100) as claimed in claim 1, wherein the plurality of reservoirs (204) have a depth in range of 2-4 millimeters (mm).
4. The heating assembly (100) as claimed in claim 1, wherein the thickness of the metal plate (102) is in range of 8-10 mm.
5. The heating assembly (100) as claimed in claim 1, wherein the heat retaining substance is one of an aluminum oxide powder, magnesium oxide powder, cenosphere, and silicon oxide powder or a mixture of at least two of them.

6. An induction iron (300) comprising:
a housing unit (302);
a heating assembly (304) coupled to the housing unit (302), the heating assembly (304) comprising:
a metal plate (306), wherein the metal plate (306) receives electromagnetic radiation to heat up the metal plate (306);
plurality of holding elements (308) on the metal plate (306) to hold a heat retaining substance (310), wherein the holding elements (308) are a plurality of reservoirs (308-1), and wherein the heat retaining substance (310) is contained in the plurality of reservoirs (308-1).
7. The induction iron (300) as claimed in claim 6, wherein the heating retaining substance (310) is contained in the plurality of reservoirs (308-1) in the form of at least one of pellets, powder, granules.
8. The induction iron (300) as claimed in claimed 6, wherein the heat retaining substance (310) is one of an aluminum oxide power, magnesium oxide powder, cenosphere, silicon oxide powder.
9. The induction iron (300) as claimed in claim 6, wherein a retention plate is used to hold the heat retaining substance (310) in the plurality of holding elements (308).