WO1988003579A1

WO1988003579A1 - Ironing apparatus

Info

Publication number: WO1988003579A1
Application number: PCT/GB1987/000029
Authority: WO
Inventors: Geoffrey Duff
Original assignee: Beldray Limited
Priority date: 1986-11-11
Filing date: 1987-01-19
Publication date: 1988-05-19
Also published as: GB8626883D0; AU6891587A

Abstract

Ironing apparatus inlcudes a cordless hand held flat iron (10) not provided with any integral heating means. A rest station (18) for the iron, e.g. incorporated in a conventional portable ironing board (15), includes energy emitting means, for example one or more tungsten halogen lamps (20) having substantially no thermal inertia, the lamp being activated by a proximity sensor (23) at the station and the heating of the iron sole plate (11) being regulated by thermostatic means including a heat sensing device (24) at the station. A screen (19) formed of glass or other material having high permeability to infra-red radiation may protect the heat source and the iron may rest on or immediately above this at the station. In an alternative construction the energy emitting means is an induction coil generating a magnetic field to cause heating of a metal body of the iron.

Description

IRONING APPARATUS

This invention relates to apparatus, particularly but not exclusively for domestic use, for ironing clothes or other fabrics and materials and more specifically to heating means for irons.

In the days before mains electricity became generally available irons were used which did not incorporate any integral heating means, the sole plate of the iron had to be re-heated from time to time during use from a substantially uncontrolled 10 heat source such as an open fire, solid fuelled stove hotplate or some kind of gas fuelled burner. The irons .used were cumbersome and inconvenient and the heat had to be judged by experience or guesswork. This was, perhaps, not so important 15 when fabrics were substantially composed of natural fibres but the ironing heat to be applied to many modern artificial fibre materials is critical and close and accurate control of the maximum heat is practically essential.

Irons most commonly used today incorporate integral heating means in the form of electric elements incorporated in the sole plate structure, usually thermostatically controlled and necessitating connection of the iron by a flexible wire cord to a power point. Because of the movement of the iron during use and coiling for storage the cord is subjected to substantial wear and tear,^" even to the extent that after a relatively short service life its insulation may be damaged and the iron may possibly become electrically unsafe without the user being aware of it. -Moreover, the cord is often inconvenient in use as it hampers the free movement of the iron and the manoeuvring of the articles being ironed. Resilient, spring-loaded or other cord supports or guides are available, for example for attachment to portable ironing boards, but these do not entirely solve the problem and are an additional piece of equipment to be provided and to be connected and disconnected when the iron and board are got out or put away.

The trailing cord is also a hazard in that if it is caught e.g. by -someone tripping over it or a child pulling the cord the hot iron may be pulled off the board or other surface to cause injury or possibly burns and/or to cause a fire hazard if it has been switched on and left -unattended.

Proposals for overcoming the above disadvantages by the provision of "cordless" irons have been made. British Patents 543214 and 705269 describe flat irons which have no heating elements but are replaced at a station incorporating a hot plate or other body heated electrically for heat to be transferred by contact to the iron sole plate. This is inefficient as energy is wasted in maintaining the heat of the body; even if a switch is incorporated so that electricity is only used when the iron is in place the heating and cooling of the body is wasteful. The arrangement is also undesirable from a safety view, contact with the body e.g. by children is possible.

Cordless electric irons have also been proposed in which provision for energy storage within the structure o the iron or the sole plate itself is provided either in the form of rechargeable electric batteries or in the form of having a large volume of metal in the sole plate to act in the manner of a storage heater in conjunction with heating elements in the iron which are connected to the power supply only when it is moved to the rest position. These proposals have not proved successful in practice as they add considerably to the bulk, weight, complication and cost of the iron itself. Moreover they depend on reliable and safe electrical contact being made with the power source at the rest station each time the iron is moved thereto, thus the contacts or other plug-in devices are subjected to substantial wear and tear and are not found to be reliable, moreover the iron has to be precisely positioned at the rest station each time to make the necessary contact. Precise positioning of the iron is not required using the arrangement of the invention.

The object of the invention is to provide ironing apparatus and/or heating means for irons which is particularly convenient and reliable in use, particularly safe in operation, and which is economical to provide, conveniently in combination with a portable ironing board.

According to the invention there is provided ironing apparatus comprising a hand held iron having sole plate structure which is applied when heated to material to be ironed in use and a station where the iron can be rested for reheating during ironing at times when it is not being so applied; characterised in that structure of said station includes energy transfer means comprising one or more substantially instantaneously acting energy emitters operable to radiate an energy field or fields which coact with said sole plate structure to cause heating thereof when at the station without causing any substantial heating of the structure of the station in use, means for automatically sensing the presence of the iron in or at the station and activating the energy transfer means in response thereto, and means for sensing the temperature of the sole plate and regulating the energy transfer means to heat the plate to a preselected temperature while at the station.

In one form of the invention the energy transfer means comprises radiant heat emitters.

Preferably the radiant heat emitters are screened by material having high permeability to infra-red radiation to permit effective passage of radiant heat to the sole plate but which does not itself become substantially heated. Conveniently the heat emitters are one or more tungsten-halogen lamps, for example as supplied by Thorπ-Efll and used in electric cooking hobs, which have substantially no thermal inertia so that they heat almost instantaneously when switched on and cool almost instantaneously when switched off.

The screening material may be glass sheet, for example as supplied by Corning Glass, or sheet plastics material for example as supplied by General Electric Plastics, both said materials being substantially transparent to radiation at infra-red and adjacent wavelengths.

In another form of the invention the energy transfer means comprises electrically powered induction means for generating an alternating magnetic field which will cause heating of an electrically conductive body of the sole plate structure while the iron is in or at the station.

Conveniently said induction heating means will include one or more induction coils which may be disposed in surrounding relationship to the iron sole plate with the latter positioned at the station or may be positioned in co-acting relationship thereto, e.g. a "pancake" shaped coil in parallel relationship to the underface of the sole plate. A dielectric separator may be provided between the coil and sole plate.

The iron may be a "dry" iron or it may include provision for steaming and/or damp^'iπg the articles being ironed.

Examples of the invention are now more particularly described with reference to the accompanying drawings, wherein:-

Figure 1 is a perspective view of a first embodiment of the invention comprising an iron and portable ironing board;

Figure 2 is a sectional view of heating means thereof;

Figure 3 is a like view of an alternative form of heating means;

Figure 4 is a diagram of an electrical circuit thereof; _ Figure 5 is a perspective view of ironing apparatus being a second embodiment of the invention;

Figure 6 is a diagrammatic detail view of part of the apparatus of Figure 5 showing one form of induction coil; and

Figure 7 is a perspective view of an alternative form of induction coil.

Referring firstly to Figure 1 the apparatus comprises a flat iron 10 having a sole plate 11 and handle 12. The iron itself does not incorporate any heating means, thus it can be simple and light in construction, durable, and does not require any connecting flex cord. A portable ironing board 15 of generally conventional shape includes an ironing surface 16 supported in use by foldable tubular metal or other legs 17, an area at one end of the board forms a rest or station 18 on which the iron is placed by the user at times when an actual ironing operation is not being carried out.

Field tests have shown that the iron is taken off the ironing surface to rest during a surprisingly high proportion of the total ironing time e.g. while the garment or other material being ironed is re¬ arranged on the board or while one garment or article is being removed and folded and the next one substituted.

The upper surface of station 18 is constituted by a sheet or material forming a screen 19 (see also Figure 2) which is substantially transparent to radiation at and around infra-red wave lengths, i.e. radiant heat will pass readily through the screen without substantially heating the screen material itself. One example of such material is a plastics sheet manufactured by General Electric Plastics.

Below the screen 19 are located one or more heat sources in the form of electrically powered tungsten halogen heating lamps 20, for example those produced by Thorn-EMI for cooking hobs which have virtually no thermal inertia, i.e. they come up to full heat almost instantaneously on switch on and cool substantially instantaneously when the current is turned off.

Small ridges 21 or other surface projections are provided on the top of screen 19 so that, when iron 10 is rested thereon, the bottom surface of sole plate 11 is spaced slightly above the top surface of screen 19 to reduce back transmission of heat by conduction from the sole plate to the screen.

The heating means incorporated in the end portion of the board 15 is connected to an electric power source by a flexible cord 22 and it will be noted that this cord is anchored to the structure of the board 15 which will not normally be moved during use, i.e. there is no wear and tear on the cord apart from its connection and disconnection and storage with the ironing board.

Station 18 incorporates a proximity sensor 23, conveniently mounted in screen 19, which responds to the presence of iron 10 at rest on station 18 to switch on the electric circuit connected to lamps. 20.

A thermocouple or other heat sensing device 24 is conveniently located in a small aperture through screen 19 at its central region so that it responds to the temperature of the iron sole plate 11 when at rest to control thermostatically the operation of the heating lamps 20 by way of a relay 29 (Figure 4) and maintain the maximum temperature to which the sole plate is heated to a predetermined level. This temperature can be selectively adjusted by a suitable setting knob 25 on board 15 which may be calibrated for the heat settings appropriate to different types of fabric and materials.

As lamps 20 act substantially instantaneously and are only heated when the iron is in the rest position, and as screen 19 does not itself become substantially heated during operation the risk of accidental burning e.g. if a child should touch the station area 18 of the board is substantially reduced. The rest area of station 18 may be so shaped that the heating means is substantially covered by the iron sole plate when in position thereon to reduce any risk of accidental contact or burning.

It is believed that by allowing a slight clearance around the heat sensing device 24 it will not be substantially affected by any localised heating of screen 19 or otherwise below sole plate 11 so that it will give a true reading of the temperature of the latter, particularly if material having the appropriate properties is selected for forming the screen as referred to above. However, an alternative construction will now be described in which the sensing device still senses the temperature of the sole plate bottom surface directly, but this sensing is divorced from the action of the heating means.

An arrangement providing the latter facility is illustrated in Figure 3. Here a surface at station 18 on which the sole plate 11 of the iron 10 rests is formed from heat insulating material 30 which incorporates the thermocouple or other heat sensing device 24 as referring to above acting directly to sense the temperature of the sole plate bottom surface. In this arrangement the heating means comprising lamps 20A is positioned operatively above the sole plate 11 when the iron is at the station 18 in a casing 31 cantilevered above or bridging the rest station. A screen 19A of infra-red transparent material e.g. the plastics referred to above forms the floor of enclosure 31, the heat from lamps 20A being directed downwards onto sole plate 11. The operation of this arrangement is otherwise substantially as described above. This arrangement may have an advantage in that the heating means is less readily accessible and less likely to be accidentally touched, particularly when the iron is in position.

It is contemplated that temperature control of the heating means might be provided by other means, for example known electrical or electronic temperature - control devices such as that known as a "Simmerstat".

In a modified form of the example shown in Figures 1 and 2 instead of a continuous screen 19 the lamps 20 are shielded by a low mass wire or other mesh or grille across an opening into or above which the sole plate 11 of the iron seats or locates when at rest. 'The gauge of wire used is small so that it does not absorb or hold any substantial heat and will cool almost instantaneously when the iron is removed .

Referring now to Figures 5, 6 and 7 an embodiment using induction heating is shown. Iron 210 has a metal sole plate 211 and handle 212 similar to that already described and, in this example, is used with a similar portable ironing board 215, its ironing surface 216 supported by legs 217 and with a rest or station 218 at one end.

The upper surface of station 218 is constituted by a sheet of di-electric material 219.

Below the sheet 219 is located induction means, in this example consisting of a single high frequency induction coil 220 of "pancake" shape as best seen in Figure 6, preferably the windings of coil220 are arranged in a shallow conical helix about an axis normal to sheet 219 rather than a flat spiral coil for the most effective operation.

Small ridges or other surface projections may be provided on the top of sheet 219 so that, when iron 210 is rested thereon, the bottom surface of sole plate 211 is spaced slightly above the top surface of screen 219 to reduce back transmission of heat by conduction from the sole plate to the screen.

The induction means incorporated in the end portion of the board 215 is connected to an electric power source by way of control means (not shown) mounted in or below said end portion and a flexible cord 222 as in the case of the first embodiment.

Station 218 incorporates a proximity sensor 223, conveniently mounted in sheet 219, which responds to the presence of iron 210 at rest on station 218 to activate the control means connected to coil 220. The alternating magnetic field generated by coil 220 induces eddy currents in the metal sole plate 211 which heats the latter but it will be noted that the coil itself, the sheet 219 and other structure at or around station 218 is not heated to any substantial degree.

A thermocouple or other heat sensing device 224 is conveniently located in a small aperture through sheet 219 e.g.- at its central region so that it responds to the temperature of the iron sole plate 211 when at rest to control thermostatically the operation of the coil 220 by way of the control means and maintain the maximum temperature to which the sole plate is heated to a predetermined level selectively adjusted by a setting knob.225.

Coil 220 may operate at a frequency of 200 - 500 kHz to give reasonably deep heating within the body of sole plate 211, however, other frequencies may be used depending on the size, shape and composition of the plate or of a metal body incorporated in the plate structure. An alternative induction arrangement is illustrated in Figure 7. Here station 218 is provided with an induction coil 220a in the form of a flattened cylinder into which the sole plate 211 of the iron 210 is inserted when at rest. The turns of the coil are axially tapered to match the shape of the plate 211 for the most efficient heating effect. Appropriately arranged proximity and heat sensing devices control the operation of the coil as referred to above.

It is believed that much more accurate .and coπsistant control of the temperature of the iron may be achieved using the invention. Conventional irons heated by electrical resistance elements may have large variations in temperature at a given thermostat setting with consequent risk of damage to many modern fabrics, particularly those incorporating artificial fibres.

The transmission of energy by induction does involve some energy loss but this is balanced by the rapidity of the heating effect (which is only called for intermittently) and the absence of residual heating of the station structure, i.e. there is no waste heat to be dispersed.

There are very substantial safety advantages, only a metal body can be heated by induction thus there is no risk of flammable materials becoming even in the unlikely event of the proximity sensor beiπg_ actuated or tempered with. A small metal body such as a metal garment button will not operate the proximity sensor.

Suitable shielding may be provided to prevent radio or T.U. interference.

While the above examples embody a portable folding ironing table or board it is also contemplated that the invention may be applied to non-portable or other forms of ironing table and/or to apparatus in the form of a clip-on or other dis ountable or portable accessory or attachment e.g. for use with a folding or other table or board.

The iron 10 or 210 may incorporate a reservoir for a supply of water or other damping fluid with provision for selective emission of a spray of fluid and/or of steam,^" e.g. from apertures in the bottom surface of the sole plate 11 or 211, the fluid being vaporised by the heated sole plate structure in the manner of a steam iron of conventional construction.

Claims

1. Ironing apparatus comprising a hand held iron having sole plate structure which is applied when heated to material to be ironed in use and a station where the iron can be rested for reheating during ironing at times when it is not being so applied; characterised in that structure of said station (18,218) includes energy transfer means comprising one or more substantially instantaneously acting energy emitters (20, 220) operable to radiate an energy field or fields which coact with said sole plate structure (11,211) to cause heating thereof when at the station without causing any substantial heating of the structure of the station in use, means (23,223) for automatically sensing the presence of the iron in or at the station and activating the energy transfer means in response thereto, and means (24, 224) for sensing the temperature of the sole plate and regulating the energy transfer means to heat the plate to a preselected temperature while at the station.

2. Apparatus as in Claim 1 characterised in that the or each energy emitter is a radiant heat emitter.

3. Apparatus as in Claim 2 characterised in that each said heat emitter is a tungsten-halogen lamp

(20).

4. Apparatus as in Claim 2 or 3 characterised in that the heat emitters (20) are shielded by a material having high permeability to infra-red radiation to permit effective passage of radiant heat to the sole plate but which does not itself become substantially heated.

5. Apparatus as in Claim 4 characterised in that said material is a glass sheet forming a screen (19).

6. Apparatus as in Claim 4 characterised in that the material is a sheet plastics material forming a screen (19).

7.- Apparatus as in Claim 5 or 6 characterised in that the sole plate rests on or immediately above the screen (19) when at the station, the top of the screen structure being provided with ridges or other projections (21) spacing the bottom of the sole plate slightly away .from said upper surface.

8. Apparatus as in Claim 4 characterised in that the material is a low mass wire or other mesh or grille.

9. Apparatus as in any one of Claims 2 to 7 characterised in that said station includes a surface (30) formed from a heat insulating material on which said sole plate rests, the radiant heat emitter or emitters being disposed above the sole plate when the iron is at the station.

10. Apparatus as in Claim 9 characterised in that the surface on which said sole plate rests incorporates the temperature sensing means (24) acting directly to sense the temperature of the sole plate bottom surface.

11. Apparatus as in Claim 7 characterised in that the temperature sensing means (24) is located in an aperture at a central region of the screen (19).

12. Apparatus as in Claim 7 or 11 characterised in that said means for sensing the presence of the iron is a proximity sensor (23) mounted in the screen (19).

13. Apparatus as in Claim 1 characterised in that the sole plate structure includes a body (211)^' of electrically conductive material and the energy transfer means includes electrically powered induction means (220,220a) for generating an alternating magnetic field coacting with said body to cause the heating of the sole plate structure.

1 . Apparatus as in Claim 13 characterised in that the induction means includes one or more inductive coils (220,220a).

15. Apparatus as in Claim 14 characterised in that said coil or coils (220a) are disposed in surrounding relationship to the sole plate structure (211) when the iron is at the station.

16. Apparatus as in Claim_14 characterised in that said coil or coils (22) are positioned in a parallel face to face relationship to an underface of the sole plate structure (211).

17. Apparatus as in Claim 16 characterised in that the station includes a separator (219) of a di¬ electric material between the induction means (220) and the sole plate structure (211).

18. Apparatus as in any one of Claims 13 to 17 characterised in that the induction means (220,220a) operates at a frequency of 200 to 500kHz.

19. Apparatus as in any preceding claim characterised in that the iron (10,210) includes provision for the emission of steam or a spray of liquid while ironing.

20. Apparatus as in any preceding claim characterised in that the station (18,218) forms part of a portable ironing board (115,215).