Title:
STEAM CLEANER AND STEAM IRON APPARATUS
Kind Code:
A1


Abstract:
A combination steam cleaner and steam iron includes a steam generator, a steam cleaner and a steam iron. The steam generator includes a control device connected to a boiler element for boiling water to produce steam. The steam iron includes an iron heating element and a thermostat. The steam generator receives a maximum amount of power except when the iron thermostat is closed and the iron heating element requires power; the amount of power delivered to the boiler element is then reduced. The control device includes a circuit configured to deliver electrical power to the boiler element with a preset duty cycle, so that the reduced amount of power is a fraction of the maximum power in accordance with the duty cycle.



Inventors:
Rosenzweig, Maximilian (Montreal, CA)
Mcgee, Brian R. (Auburn, AL, US)
Vrdoljak, Ognjen (Laval, CA)
Application Number:
11/463774
Publication Date:
02/14/2008
Filing Date:
08/10/2006
Primary Class:
International Classes:
D06F75/10
View Patent Images:



Primary Examiner:
PELHAM, JOSEPH MOORE
Attorney, Agent or Firm:
Michael I. Wolfson (New York, NY, US)
Claims:
We claim:

1. A steam iron, comprising: a steam generating unit including a first heating element, a first thermostat coupled to the first heating element, and a control device for controlling electrical power delivered to the first heating element; and a steam iron unit including a second heating element, and a second thermostat coupled to the second heating element, wherein the control device causes delivery to the first heating element of one of (1) a maximum amount of electrical power and (2) a reduced amount of electrical power less than the maximum amount, in accordance with a state of the second thermostat.

2. A steam iron according to claim 1, wherein the first thermostat is in one of (1) an open state in which the first heating element is not caused to generate heat and (2) a closed state in which the first heating element is caused to generate heat, the second thermostat is in one of (1) an open state in which the second heating element is not caused to generate heat and (2) a closed state in which the second heating element is caused to generate heat, the control device causes delivery of the maximum amount of electrical power to the first heating element in accordance with the first thermostat being in the closed state and the second thermostat being in the open state, and the control device causes delivery of the reduced amount of electrical power to the first heating element in accordance with the first thermostat being in the closed state and the second thermostat being in the closed state.

3. A steam iron according to claim 2, wherein the control device includes a half-wave rectifier for delivering electrical power to the first heating element with a 50% duty cycle, so that the reduced amount of electrical power is 50% of the maximum amount.

4. A steam iron according to claim 3, wherein the control device further includes a relay energized in accordance with the second thermostat being in the closed state, the relay thereby coupling the half-wave rectifier to the first heating element.

5. A steam iron according to claim 2, wherein the control device includes a circuit configured to deliver electrical power to the first heating element with a preset duty cycle, so that the reduced amount of power is a fraction of the maximum power in accordance with said duty cycle.

6. A steam iron according to claim 5, wherein the control device further includes a relay energized in accordance with the second thermostat being in the closed state, the relay thereby coupling said circuit to the first heating element.

7. A steam iron according to claim 5, wherein said circuit includes a gated conductor device.

8. A steam iron according to claim 7, wherein said circuit further includes a timer device, the gated conductor device is configured to conduct current in accordance with a signal at the gate thereof from the timer device, and the duty cycle is preset in accordance with values of resistances coupled to the timer device.

9. A steam iron according to claim 8, wherein said circuit further includes a DIP switch device for setting the values of the resistances.

10. A steam iron according to claim 8, wherein the resistances include a variable resistor.

11. A steam iron according to claim 1, wherein the steam generating unit has a single heating element.

12. A steam iron according to claim 1, wherein the maximum amount of electrical power is approximately 1800 watts.

13. A steam iron according to claim 1, further comprising a steam cleaner unit.

14. A combination steam cleaner and steam iron, comprising: a steam generating unit including a first heating element, a first thermostat coupled to the first heating element, and a control device for controlling electrical power delivered to the first heating element; a steam cleaner unit; and a steam iron unit including a second heating element, and a second thermostat coupled to the second heating element, wherein at most one of the steam cleaner unit and the steam iron unit is coupled to the steam generating unit, and upon coupling of the steam iron unit to the steam generating unit the control device causes delivery to the first heating element of one of (1) a maximum amount of electrical power and (2) a reduced amount of electrical power less than the maximum amount, in accordance with a state of the second thermostat.

15. A combination steam cleaner and steam iron according to claim 14, wherein the first thermostat is in one of (1) an open state in which the first heating element is not caused to generate heat and (2) a closed state in which the first heating element is caused to generate heat, the second thermostat is in one of (1) an open state in which the second heating element is not caused to generate heat and (2) a closed state in which the second heating element is caused to generate heat, the control device causes delivery of the maximum amount of electrical power to the first heating element in accordance with the first thermostat being in the closed state and the second thermostat being in the open state, and the control device causes delivery of the reduced amount of electrical power to the first heating element in accordance with the first thermostat being in the closed state and the second thermostat being in the closed state.

16. A combination steam cleaner and steam iron according to claim 14, wherein the steam generating unit has a single heating element.

17. A combination steam cleaner and steam iron according to claim 14, wherein the maximum amount of power is approximately 1800 watts.

18. A combination steam cleaner and steam iron according to claim 14, wherein the control device includes a circuit configured to deliver electrical power to the first heating element with a preset duty cycle, so that the reduced amount of power is a fraction of the maximum power in accordance with said duty cycle.

19. A combination steam cleaner and steam iron according to claim 14, wherein the control device includes a half-wave rectifier for delivering electrical power to the first heating element with a 50% duty cycle, so that the reduced amount of electrical power is 50% of the maximum amount.

20. A combination steam cleaner and steam iron according to claim 14, wherein the steam generating unit further includes a steam release valve, the steam cleaner unit includes a first steam release switch, and the steam iron unit includes a second steam release switch, so that upon coupling of the steam cleaner unit to the steam generating unit, closing of the first steam release switch causes release of steam via the steam release valve, and upon coupling of the steam iron unit to the steam generating unit, closing of the second steam release switch causes release of steam via the steam release valve.

Description:

FIELD OF THE INVENTION

The present invention relates to steam cleaners and steam irons and, more particularly, to an improved steam cleaner and steam iron apparatus.

BACKGROUND OF THE INVENTION

Steam cleaning appliances require a substantial amount of power to operate properly. Typically, steam cleaning appliances require around 1500 watts of power (1800 watts maximum) to sufficiently heat stored water to provide the necessary steam for the cleaning appliance.

Similarly, steam generating irons require a substantial amount of power to operate properly. Steam generating irons generally include two heating elements, one to heat the iron and the other to heat water to produce steam. In the United States, the combined amount of electrical power utilized by both heating elements, for practical purposes, exceed 1800 watts due to UL regulations limiting voltage levels to 120 volts, with a maximum draw of 15 amps at this voltage level. A combined steam cleaner and steam iron includes a base unit (having a boiler tank, heating element, power switch and safety devices) with both a detachable steam cleaner accessory and a steam iron accessory; only one of the accessories may be used at one time. The combined wattage of the base and the iron may not exceed 1800 watts.

Given these power constraints, a device that combines a steam cleaner with a steam iron would not be able to draw sufficient power to power the separate heating elements of the combined device. One attempt to overcome this problem is disclosed in European Patent No. EP 0 809 728 B1. The design shown therein is intended for use in Europe, which generally has line voltage of 220 volts and power standards suitably high that provide sufficient power to a device that includes both a steam cleaner and a steam iron.

A combined steam cleaner and steam iron apparatus which overcomes the problem of power constraint in the U.S. is described in commonly owned U.S. Pat. No. 6,711,840, incorporated by reference herein. However, the apparatus described in the '840 patent requires two separate heating elements for the boiler. There remains a need for a combined steam cleaner and steam iron with a reduced number of components necessary to perform the desired function (that is, a single boiler heating element), thus reducing the cost of the combined unit.

It therefore is desirable to provide a simple, low cost, combined steam cleaner and steam iron apparatus designed to properly operate under restricted power requirements. In particular, it is desirable that the apparatus be able to regulate the power drawn by the boiler under various conditions, such as when heating the iron.

SUMMARY OF THE INVENTION

The present invention addresses the above-described need by providing a combination steam cleaner and steam iron that includes a steam generator, a steam cleaner and a steam iron. The steam generator includes a control device connected to a boiler element for boiling water to produce steam. The steam iron includes an iron heating element and a thermostat. The steam generator receives a maximum amount of power except when the iron thermostat is closed and the iron heating element requires power; the amount of power delivered to the boiler element is then reduced. The control device may include a circuit configured to deliver electrical power to the boiler element with a preset duty cycle, so that the reduced amount of power is a fraction of the maximum power in accordance with the duty cycle.

The control device may include a half-wave rectifier for delivering electrical power to the first heating element with a 50% duty cycle, so that the reduced amount of electrical power is 50% of the maximum amount. The control device may further include a relay energized in accordance with the iron thermostat being in the closed state, the relay thereby coupling the half-wave rectifier to the boiler heating element.

The control device may also include a gated conductor device and a timer device, where the gated conductor device is configured to conduct current in accordance with a signal at the gate from the timer device. The duty cycle is preset in accordance with values of resistances coupled to the timer device.

The boiler element is preferably a 1500 watt (up to 1800 Watt) heater and the iron heating element is preferably a 600 watt heater. About 1500 watts of power are drawn during use of the steam cleaner and about 1500 watts of power are drawn during use of the steam generator and the steam iron.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings in which like reference numbers indicate like features and wherein:

FIG. 1 illustrates a combined steam cleaner and steam iron apparatus in accordance with the present invention, shown with the steam iron attached.

FIG. 2 shows the combined steam cleaner and steam iron apparatus in accordance with the invention, shown having the steam cleaner attached.

FIG. 3 shows an embodiment of a heating element used within the combined steam cleaner and steam iron apparatus of FIG. 1 and FIG. 2.

FIG. 4 is a schematic illustration of an electrical circuit of the combined steam cleaner and steam iron apparatus of FIG. 1 and FIG. 2, according to an embodiment of the invention.

FIG. 5A is a schematic illustration of an electrical circuit for a combined steam cleaner and steam iron apparatus in which power to the boiler is regulated using a half-wave rectifier, so as to deliver power to the boiler with a 50% duty cycle, in accordance with another embodiment of the invention.

FIG. 5B is a schematic illustration of an alternative arrangement of an electrical circuit regulating power to the boiler using a half-wave rectifier, in accordance with another embodiment of the invention.

FIG. 6 is a schematic illustration of another alternative arrangement of an electrical circuit regulating power to the boiler using a half-wave rectifier, in accordance with a further embodiment of the invention.

FIG. 7 is a schematic illustration of another alternative arrangement of an electrical circuit regulating power to the boiler using a half-wave rectifier, in accordance with still another embodiment of the invention.

FIG. 8 is a schematic illustration of an electrical circuit regulating power to the boiler with a preset duty cycle other than 50%, in accordance with another embodiment of the invention.

FIG. 9A is a schematic illustration of an alternative electrical circuit regulating power to the boiler with a preset duty cycle other than 50%, in accordance with further embodiment of the invention.

FIG. 9B is a schematic illustration of an another alternative electrical circuit regulating power to the boiler with a preset duty cycle other than 50%, in accordance with still another embodiment of the invention.

FIG. 10 is a logic diagram applicable to several embodiments of the invention, illustrating the state of regulated power drawn by the boiler in accordance with the state of the steam iron thermostat.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

FIGS. 1 and 2 collectively illustrate a combined steam cleaner and steam iron apparatus, in accordance with an embodiment of the invention. The combined steam cleaner and steam iron apparatus includes a steam generator (boiler) unit 10, a steam iron unit 20 and a steam cleaner unit 30. Boiler unit 10 has a single heating element. FIG. 1 shows a boiler unit 10 in the base of the apparatus, with a steam iron 20 resting on top of and physically attached to the base via a steam iron hose 22. FIG. 2 shows a steam cleaner 30 resting on top of and physically attached to the base via a steam cleaner hose 32.

The steam generator includes a pressostat, a thermostat, and/or a thermofuse serially coupled to the boiler heating element. The steam generator also includes a top surface designed for use as a resting surface on which either the steam cleaner or the steam iron may be mounted. The top surface is designed to support a heated steam iron.

Boiler unit 10 receives electrical power via a power cable 16 that is connected to a suitable power receptacle during operation of the apparatus of the invention. Boiler unit 10 includes within its housing 14 a main on/off switch (with on/off light) 15 and also includes a heating element 18 with electrical connections thereto, shown in FIG. 3. As further discussed below, heating element 18 is located in the boiler unit and provides steam for use by both the steam iron and the steam cleaner of the invention. As best shown in FIG. 2, the base of the apparatus includes a top surface 19 designed for use as a resting surface for either the steam iron 20 or the steam cleaner 30.

Referring back to FIG. 1, steam iron hose 22 extends from the steam iron 20 and a steam iron plug 24 (also called connector) extends from the other end of the steam iron hose 22. Steam iron plug 24 is insertable into (i.e., can mate with) a socket 12 disposed within the housing 14 of the steam generating unit 10. As shown in the exemplary design of FIG. 1, steam iron 20 includes a handle 26, an on/off switch 28 and an on/off light 29. During use of the steam iron 20 of the invention, the steam iron plug 24 is inserted into socket 12.

Referring to FIG. 2, steam cleaner hose 32 extends from the steam cleaner 30 and a steam cleaner plug 34 extends from the other end of the steam cleaner hose 32. Like the steam iron plug 24, the steam cleaner plug 34 also can be inserted into socket 12 of the steam generator's housing 14. The steam cleaner 30 includes an on/off switch 36 and a nozzle 38 through which steam is supplied, as further discussed below. The steam cleaner 30 may also include a hand grip 39 for comfort.

In order to conform to the wattage constraints discussed above, the electrical current delivered to (and hence the power drawn by) heating element 18 is regulated according to the state of the thermostats (that is, on/off or heat/no heat) of the boiler unit and the steam iron unit. Various circuits and arrangements for regulating the power drawn by the boiler are described in more detail below.

Three-Pole Iron Unit Thermostat with Limiting Circuit

FIG. 4 is a schematic illustration of an electrical circuit of a combined steam cleaner and steam iron apparatus, in accordance with an embodiment of the invention. When the apparatus is in use, power cable 16 is coupled to an appropriate 120 volt power source (line connection L, typically rated at 15 Amps) with a return line and a ground connection. The power source is supplied to both the main on/off switch 15 disposed within the steam generating unit's housing 14, as well as to a steam release valve or solenoid 50 disposed within the boiler unit 10. The output (also called switched power herein) of the main on/off switch 15 is supplied to control device 70, wherein the control device 70 includes a limiting circuit (not shown) that regulates the maximum power that boiler heating element 18 can generate by a factor that can be predetermined by a manufacturer. Boiler heating element 18 is a 1500 watt (up to 1800 watt) heater device and operates to boil water within the steam generating unit 10 during use of either the steam cleaner 30 or the steam iron 20. Boiler element's 18 supply line is connected in series with two safety devices: a thermostat 54 and a thermofuse or cutoff 56. The respective operations of these various safety devices are well known in the art and thus further description is not provided herein. A neutral terminal N is connected to steam release valve 50 and connected to boiler element 18.

Socket 12 has five electrical contacts, A-D and ground, and a steam hose connection E. The switched output from main on/off switch 15 is supplied to contact B of the steam generator unit's socket 12, and contact A of socket 12 is connected to the neutral terminal of power cable 16. Contact C connects between control device 70 and boiler element 18. The supply line to boiler element 18 is connected to safety devices 54 and 56 mentioned above. As further discussed below, power supplied to contact B is routed back through contact C and then to boiler element 18 when the steam cleaner 30 is in use. When the steam iron is in use, power supplied to contact B is supplied to an iron element heater 25 disposed within the steam iron 20, wherein iron heating element's 25 supply line is connected in series through a safety device (thermal cutoff 21) and three-contact thermostat 23 to be explained in detail hereinafter. The operation of a thermal cutoff is well known in the art and thus further description is not provided herein.

Neutral terminal N is connected to steam release valve 50, as previously mentioned, and the valve's supply line is coupled to contact D of socket 12. Contact A of socket 12 is coupled to the neutral line. Both steam iron 20 and steam cleaner 30 include respective on/off switches 28 and 36. When either the steam iron or the steam cleaner is connected to boiler unit 10 (via their respective plugs 24 and 34), switching the steam on/off switch 28 or 36 of the attached device (steam iron 20 or steam cleaner 30) to the “on” position completes the circuit through steam release valve 50, thus causing steam to be released from boiler unit 10 via hose connection E (also called the steam output port) within socket 12 through the particular hose attached (22 or 32), and then to the particular device in use (steam iron 20 or steam cleaner 30). As can be seen in FIG. 4, the on/off switch (either 28 or 36) of the attached device (the steam iron or the steam cleaner) controls steam release valve 50 while power is being supplied to the boiler heater.

The steam iron 20 contains an electrical circuit as shown in FIG. 4. Plug 24 includes electrical contacts A′, B′, C′, D′ and ground, which mate with contacts A, B, C, D and ground, respectively, of the steam generator's socket 12 when plug 24 and socket 12 are attached to one another. Contact B′ is connected to a thermal cutoff 21 which connects to a three contact iron thermostat 23. Iron heating element 25 connects to the normally closed contact of iron thermostat 23 to supply power to the iron through the iron element's return attached to contact A′. Contacts B′ and D′ are attached through steam on/off switch 28 of the steam iron. The steam iron hose 22 terminates at steam hose connector E′ (also called steam input port) within the steam iron's plug 24. When the steam iron is attached to the steam generator, steam iron hose 22 receives the output of steam release valve/solenoid 50 through the hose connector E (within socket 12) and hose connector E′ (within plug 24).

The steam cleaner 30 also contains an electrical circuit as shown in FIG. 4. Plug 34 includes four electrical contacts A″, B″, C″ and D″ that mate with contacts A, B, C and D, respectively, of the steam generator's socket 12 when plug 34 and socket 12 are attached to one another. Contacts B″ and C″ are electrically connected, while contact A″ is left open. Contacts B″ and D″ are attached through steam on/off switch 36 of the steam cleaner. The steam cleaner hose 32 terminates at steam hose connector E″ (also called the steam input port) within the steam cleaner's plug 34. Similar to the steam iron, when the steam cleaner is attached to the steam generator, steam cleaner hose 32 receives the output of steam release valve 50 via hose connector E (within socket 12) and hose connector E″ (within plug 34).

The operation of the invention when the steam iron is attached to the steam generating unit will now be described. The steam iron's plug 24 is attached to the steam generator's socket 12, so that the output of steam release valve 50 is supplied to steam iron hose 22, the switched power output from main on/off switch 15 is supplied to iron heating element 25 within the steam iron 20, and steam release valve/solenoid 50 is controlled by steam on/off switch 28 within the steam iron 20. The boiler unit 10 is filled with water in a manner well known in the art, and the main on/off switch 15 is manually set to “ON” to power both boiler element 18 within the boiler 10 and to power iron element heater 25 within the steam iron 20. When the temperature of the iron is beneath the predetermined temperature threshold of the iron, the switch of iron thermostat 23 is initially in the normally closed “NC” contact position. As a result, contact C′ is effectively left open. Since contact C′ is left open, control device 70 is connected in series with boiler element 18. The amount of power that boiler element 18 is enabled to provide is the maximum power (1500 watts up to 1800 watts), regulated by the limiting circuit of the control device 70. The factor by which the boiler power is regulated is dependent upon the design of the limiting circuit (not shown). With the given constraint of 1800 watts, this factor must be less than or equal to approximately 70% in order for the iron to be supplied with 600 watts while the boiler is simultaneously supplied 1100 watts. The boiler 10 and the steam iron 20 then collectively draw less than 15 amps of current (at 120 volts). During this time, steam on/off switch 28 on the steam iron is kept in the “off” position. Boiler element 18 causes the water in the boiler tank to boil to produce steam, and iron heating element 25 heats the bottom surface of the steam iron 20. Upon sufficient heating of steam iron 20 by iron element heater 21, ironing is carried out in a manner well known in the art. Likewise, steam produced within boiler 10 is supplied through the steam iron upon switching steam on/off switch 28 to its “on” position (or depression of a button or other suitable on/off device). As previously mentioned, during use of steam iron 20, the steam iron may be conveniently placed on the top surface 19 of the steam generator. Upon completion of steam ironing, both main on/off switch 15 and steam on/off switch 28 are set to the “off” position and plug 24 is removed from the steam generator's socket 12.

Iron heating element's 25 supply line is connected in series through a safety device (thermofuse or thermal cutoff) 21. Iron thermostat 23 includes three contacts: common “COM”, normally closed “NC”, and normally open “NO”. Initially, when the iron is below a predetermined temperature designated for a threshold of the thermostat 23, the state of the thermostat is such that common contact “COM” is connected to the normally closed contact “NC”. After the iron reaches the predetermined temperature of the thermostat, the thermostat state shifts so that the contact “COM” is connected to the normally open contact “NO”. At this point, voltage is supplied to contact C′. As a result, the iron heating element 25 does not receive the previously supplied voltage which was applied to the normally closed contact “NC” before the threshold temperature was reached. Thus, the iron 20 does not heat. In the alternative, power supplied from contact B′ is supplied directly to contact C′ and C; thereby, delivering the full amount of power supplied by the line terminal of power cable 16 to the boiler element 18.

To utilize the steam cleaner 30, the steam cleaner's plug 34 is attached to socket 12 of the steam generator. As previously mentioned, such connection provides the switched power (output from main on/off switch 15) to boiler element 18 alone, where the control device 70 is bypassed since contacts B″ and C″ are electrically connected. The effect of bypassing the control device 70 is that boiler element 18 draws the maximum power of 1500-1800 watts for boiling the water to generate steam. The output of steam release valve 50 is supplied to steam cleaner hose 32, and steam release valve 50 is controlled by steam on/off switch 36 within the steam cleaner 30. The tank in boiler 10 is filled with water and the main on/off switch 15 is set to its “on” position, to power boiler element 18 at the maximum power of 1500 to 1800 watts. Boiler element 18 thus draws less than 15 amps of current (at 120 volts). Steam on/off switch 36 on the steam cleaner is initially kept off. Steam cleaning then is performed by turning steam on/off switch 36 to its “on” position, to supply the steam through the steam cleaner hose 32 and out through nozzle 38. Upon completion of steam cleaning, both switches 15 and 36 are turned off and the connectors are detached.

As can be appreciated from the foregoing discussion and designs shown in FIG. 4 of the invention, the herein-described combination steam cleaner and steam iron properly functions within the constraint of a 1800 watt (120 volts; 15 amps) source of power. The inventive design further advantageously minimizes the size and number of contacts required for the various plugs and sockets of the combination's components. It is also noted that the voltage supply can be an amount of voltage other than the line 120 volt power supply which is shown in FIG. 4.

Two-Pole Iron Thermostat with 50% Boiler Duty Cycle

FIG. 5A illustrates another embodiment of the invention, in which power drawn by the boiler heating element 18 is regulated using a half-wave rectifier. Socket connector 12 in boiler unit 10 has five electrical connectors which mate with the connectors in plug 24 or plug 34 in the iron unit 20 or steam cleaner unit 30 respectively. When the steam iron unit 20 is plugged into the boiler unit 10, the path from line connection L to neutral connection N has iron thermal fuse 21, iron thermostat 27 and iron heating element 25 connected in series through connectors 4 (line connection) and 2 (neutral connection). Boiler unit 10 includes a relay 58 connected to the neutral terminal and to the iron unit through connector 3. Relay 58 has two relay contacts 58-1 and 58-2; contact 58-1 (normally closed) is connected to line terminal L, while contact 58-2 is connected to line terminal L through diode 57 which serves as a half-wave rectifier for the line current. Thermostat 54 and heating element 18 of the boiler are connected in series with relay 58.

When the iron thermostat 27 is open (that is, the iron is at the required temperature and is not calling for heat), no current is present in either heating element 25 or in the coil of relay 58. Contact 58-1 then remains closed, and full power may be drawn by the boiler whenever thermostat 54 is closed. However, when iron thermostat 27 is closed, heating element 25 is connected to the line terminal and relay 58 is energized. This causes relay contact 58-1 to open and contact 58-2 to close, which in turn causes half-rectified current to be delivered to boiler thermostat 54 and boiler heating element 18. Accordingly, when the iron unit calls for heat, full power is delivered to iron heating element 25, while power delivery to boiler heating element 18 (when boiler thermostat 54 is closed) is reduced to a 50% duty cycle.

This arrangement allows for the iron unit to have priority in receiving heating current while permitting the boiler to receive maximum heating current when not required by the iron. This in turn provides improved system performance within the constraint of overall maximum power dissipation.

The solenoid of steam release valve 50 is connected to the line terminal and to steam release switch 28 of the iron unit (or steam release switch 34 of the steam cleaner unit 30) through connector 1. As in the previously described embodiment, steam is released from the steam iron via steam release valve 50 when steam release switch 28 is closed (thereby energizing the solenoid of steam release valve 50). Similarly, when steam cleaner 30 is connected to the boiler unit, steam is released when switch 36 is closed.

FIG. 5B illustrates an embodiment similar to that of FIG. 5A, except that the unswitched terminal of steam release valve 50 is connected to neutral terminal N instead of line terminal L. Accordingly, the solenoid of valve 50 is connected to line voltage only when switch 28 or 34 (depending on whether iron unit 20 or steam cleaner unit 30 is connected to boiler 10) is closed.

FIG. 6 illustrates another embodiment similar to that of FIG. 5A, with the addition of a double-pole illuminated power switch 15P provided for boiler unit 10. A resistor and lamp (preferably green), in parallel with boiler thermostat 54, serves as a ‘steam ready’ indicator 55. When the boiler has reached its required temperature, thermostat 54 opens so that indicator 55 conducts current and the lamp illuminates. This arrangement also permits release of pressure from the boiler unit using solenoid 50 regardless of the on/off state of switch 15P. This allows the user to refill the unit more quickly and safely.

FIG. 7 illustrates an alternative embodiment, similar to that of FIG. 5B but without relay 58. In the embodiment shown in FIG. 7, thermal fuse 56, thermostat 54, heating element 18 and half-wave rectifying diode 57 are all connected in series between line terminal L and neutral terminal N. Accordingly, when iron unit 20 is connected to boiler unit 10, boiler unit 10 receives power at a 50% duty cycle at all times, independent of the state of iron thermostat 27. However, when steam cleaner 30 is connected, diode 57 is bypassed and boiler unit 10 receives full power. Compared to previously described embodiments, this embodiment provides a lower power, more slowly heating boiler with a simpler and less costly regulating circuit. As in the embodiment of FIG. 6, this arrangement also permits release of pressure from the boiler unit using solenoid 50 regardless of the on/off state of switch 15P, which allows the user to refill the unit more quickly and safely.

Two-Pole Iron Thermostat with Variable Boiler Duty Cycle

FIG. 8 illustrates an electrical circuit regulating power to the boiler with a preset duty cycle other than 50%, in accordance with another embodiment of the invention. This embodiment is similar to that shown in FIG. 6, except that the half-wave rectifying diode is replaced by a control circuit 80 for delivering power to the boiler heating element at a preset duty cycle. Circuit 80, preferably realized using a printed circuit board, includes a gated conductor (e.g. a triac) 81, an optocoupler 82, resistors 83-1 and 83-2, and a timer 84. Timer 84 is connected as an astable multivibrator, producing an output with a duty cycle related to the values of resistors 83-1 and 83-2. The output of timer 84 is connected to optocoupler 82, which in turn is connected to the gate of triac 81. When triac 81 becomes conducting, line voltage appears at contact 58-2 of relay 58. As discussed above, when iron thermostat 27 is closed the solenoid of relay 58 is energized, causing relay contact 58-2 to close and thus provide regulated power to boiler heating element 18. Accordingly, power to boiler heating element 18 is regulated in accordance with a preset duty cycle determined by the values of resistors 83-1 and 83-2. This duty cycle will typically be different from the 50% duty cycle available in the previous embodiments.

As in the embodiment of FIG. 6, this arrangement also permits release of pressure from the boiler unit using solenoid 50 regardless of the on/off state of switch 15P, which allows the user to refill the unit more quickly and safely.

FIG. 9A shows an additional embodiment of the invention wherein the resistors 83-1 and 83-2 of control circuit 80 are replaced by an array of resistors 83-N. These resistors are connected to a DIP switch unit 85. Setting the switches on the DIP switch unit determines the resistance paths in array 83-N, thereby setting the duty cycle of the output of timer 84. Various duty cycles for heating the boiler may therefore be chosen by choosing different DIP switch settings.

FIG. 9B illustrates another embodiment of the invention, in which resistors 83-1 and 83-2 of control circuit 80 are replaced by variable resistors 83-11 and 83-12, respectively. The duty cycle of the output of timer 84 may be adjusted by changing the resistances in resistors 83-11 and 83-12. Accordingly, in this embodiment, still more flexibility is available in the choice of duty cycle for regulating power to the boiler.

FIG. 10 is a logic diagram applicable to several embodiments of the invention, illustrating the state of regulated power drawn by the boiler in accordance with the state of the steam iron thermostat. In particular, regulation of power to the boiler depends on which attachment is used, and on the state of the iron thermostat if the iron is used. A control device, which may be configured according to various embodiments as discussed above, controls the power drawn by the boiler heating element. If the steam cleaner attachment 30 is used (logic branch 130), then the control device for the boiler heater element permits maximum power to be drawn by the boiler heating element. If the steam iron attachment 20 is used (logic branch 120), then regulation of power to the boiler depends on the state of the iron thermostat. If the iron thermostat 23 is in the “NO” position (alternatively, the iron thermostat 27 is open), then the iron is not calling for heat (logic branch 121). The boiler may then receive maximum power, as in the case of attaching steam cleaner 30. If the iron thermostat 23 is in the “NC” position (or if thermostat 27 is closed), then the iron is calling for heat (logic branch 122), and it is generally necessary to provide regulated power 123 to the boiler to meet overall power constraints. The control device is then activated, using any of the above-described arrangements, so that power to the boiler is reduced while power is supplied to the steam iron unit.

When a 120 V source of power is supplied to the steam generator, the steam generator will draw less than 15 amps of current during use of the steam cleaner, and the steam generator and the steam iron collectively will draw less than 15 amps of current while both are in use.

It will be appreciated that a boiler, steam iron and steam cleaner as described in the above embodiments offer the advantages of high performance and efficiency with a simple and cost effective design.

All the features disclosed in this specification may be replaced by alternative features serving the same, equivalent or similar purpose, as will be understood by those skilled in the art. The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.