FIELD OF INVENTION

[0001] This invention relates to a portable household appliance and in particular a cleaning appliance.

BACKGROUND OF INVENTION

[0002] A cleaning appliance is an apparatus that removes foreign matter from various surfaces in a room to clean the room. One example of a cleaning appliance is a vacuum cleaner, which suctions air using suction force of a blowing device, such as a suction motor, and separates foreign matter from the suctioned air using a filter to clean a room.

[0003] As shown in Fig. 1, a typical type of vacuum cleaner, the upright cleaner, includes an upright main body 20 and a suction body 24 integrally coupled to the lower part of the main body, so that foreign matter can be suctioned into the suction body 24 and be separated in the upright main body 20. There is also an extruding handle portion 22 for the user to grasp, so that the user can maneuver the upright cleaner over a work surface when the upright cleaner is used in an upright cleaning mode. The mechanical components such as the suction motor, the direct collection vessel, the filter, etc are all accommodated in the main body 20.

[0004] Cleaning appliances sometimes utilize a DC or AC motor like the suction motor described above to provide mechanical power for a cleaning application. In the upright cleaner for example there is sometimes more than one AC or DC motor in the apparatus, which is a brush motor arranged at the suction head. One common way of providing power to the cleaning appliance is to connect a power cord to an electricity socket in a house. In this case mains electricity can be used to energize AC motors or can be rectified to energize DC motors within the cleaning appliance

[0005] However, the use of AC a power cord on the cleaning appliances in some cases creates much inconvenience. For example the user cannot freely move the cleaning appliances around the house when the AC power cord is plugged into a fixed socket on the wall and is of insufficient length. Secondly, when the user wants to move the cleaning appliance to some areas where no AC socket is available, the cleaning appliance relying on AC power would not be able to operate. In addition, the fact that the power cord is laid on the floor and pulled to swing, causes the power cord to become dirty quickly as a lots of dust and dirt easily accumulates on the cord sheathing.

SUMMARY OF INVENTION

[0006] In the light of the foregoing background, it is an object of the present invention to provide an alternate cleaning appliance that is capable of working either by AC electricity or battery power from DC batteries.

[0007] The above object is met by the combination of features of the main claim; the sub-claims disclose further advantageous embodiments of the invention.

[0008] Another object of the invention is to provide a cleaning appliance with integrated charging circuit and battery packs so that no external charger for the cleaner battery is required.

[0009] One skilled in the art will derive from the following description other objects of the invention. Therefore, the foregoing statements of object are not exhaustive and serve merely to illustrate some of the many objects of the present invention.

[0010] Accordingly, the present invention, in one aspect, is a system for hybrid power supply of a cleaning appliance. The cleaning appliance contains a driving module for providing mechanical power for cleaning functions. The system includes an AC power inlet adapted to connect to an external power source to receive AC power therefrom, a DC power source, an on-board DC charging device connected to the DC power source, an AC/DC converter connected to the AC power inlet and configured to convert the AC power received by the AC power inlet to DC power; and a switching module connected to the DC power source and the AC/DC converter. The switching module is configured to switch between a DC power output of the AC/DC converter and a DC power output of the DC power source for providing a system output to the driving module.

[0011] In an exemplary embodiment of the present invention, the switching module is configured to automatically sense AC power incoming from the AC power inlet, and switch DC power output from the AC/DC converter to be provided to the driving module when the AC power is sensed. The switching module switches the DC power output from the DC power source to be provided to the driving module when the AC power is not sensed.

[0012] In a more preferred embodiment, the switching module contains a microcontroller and a switching device connected to the microcontroller. The microcontroller is configured to sense the AC power from the AC power inlet, and when the AC power is sensed the microcontroller controls the switching device to connect between the AC/DC converter and the driving module to provide the DC power output of the AC/DC converter to the driving module.

[0013] In one implementation the switching device is a relay coil connected and controlled by the microcontroller.

[0014] In another implementation, the AC/DC convertor is further connected to the on-board DC charging device such that the DC power output of the AC/DC convertor may also be used to charge the DC power source.

[0015] In another implementation, the on-board DC charging device is connected to a microcontroller, the microcontroller controlling operation of the on-board DC charging device according to at least one parameter of the DC power source received there from.

[0016] In a further exemplary embodiment of the present invention, the switching module contains a user-controllable switch coupled to the DC power source, the AC/DC converter and the driving module. The user-controllable switch is capable of being moved between at least a first position and a second position. When the user-controllable switch capable is in the first position, the DC power source is electrically isolated from the AC/DC converter and the driving module, and the DC power output from the AC/DC converter capable of being provided to the driving module. When the user-controllable switch capable is in the second position, the AC/DC converter is electrically isolated from the DC power source and the driving module. The DC power output from the DC power source is capable of being provided to the driving module.

[0017] In one implementation, the user-controllable switch is adapted to be moved into a third position different the first position and the second position. When the user-controllable switch is in the third position, the driving module is electrically isolated from the DC power source and the AC/DC converter, and the AC/DC converter is connected to the on-board DC charging device so that the DC power output of the AC/DC converter provided to the on-board DC charging device for charging the DC power source.

[0018] According to another aspect of the present invention, there is disclosed a unique method of automatic switching of a hybrid power supply system on a cleaning appliance. The cleaning appliance contains a driving module for providing mechanical power for cleaning functions; the method comprising the steps of: sensing, at an AC power inlet of the cleaning appliance, the presence of AC power; switching the hybrid power supply to provide DC power output from an AC/DC converter connected to the AC power inlet to the driving module, when the AC power is sensed; and switching the hybrid power supply to provide DC power output from an DC power source to the driving module, when the AC power is not sensed.

[0019] In a variation of the above method, the switching steps are carried out by a switching module of the cleaning appliance, the switching module further comprises a microcontroller and a switching device connected to the microcontroller; the microcontroller configured to sense the AC power from the AC power inlet, and when the AC power is sensed the microcontroller controlling the switching device to connect between the AC/DC converter and the driving module to provide the DC power output of the AC/DC converter to the driving module.

[0020] In a further aspect of the present invention, a suction cleaner with a hybrid power supply system contains a DC motor for providing rotary power for cleaning functions. The hybrid power supply system includes a switching module connected to a DC power source and an AC/DC converter. The switching module is configured to switch between a DC power output of the AC/DC convertor and a DC power output of the DC power source for providing a system output to the DC motor. The suction cleaner further contains a current control device configured to control the current of the DC motor in order to automatically limit the current to be within a predefined range.

[0021] There are many advantages to the present invention, as the hybrid power supply system described is able to utilize either the AC power generally available from a home AC socket or DC power stored in rechargeable batteries. The user can thus flexibly choose the work mode he desires in view the specific environment. When the AC power cord is connected, the cleaning appliance may be used in a similar way to those traditional cleaning appliance. At the same time, however, the single AC power cord can also provide power to the charging circuit, thus recharging the batteries while working. On the other hand, the user may also choose to operate the cleaning appliance in a "cordless" mode, without limitation from the connected AC power cord. The DC and AC work modes can be switched to each other automatically without any user intervention. The performance of the cleaning appliance in the present invention does not differ significantly in such AC or DC work mode.

[0022] Another advantage of the present invention is that in some of the embodiments, all the important components relating to the DC work mode, such as the battery pack and the charging device, are all embedded in the main housing of the cleaning appliance. The user therefore does not have to handle and pay attention to these components, thus increasing the convenience of operating the cleaning appliance.

[0023] By adopting the hybrid power supply system in the cleaning appliance, the cleaning tasks can now be efficiently accomplished since the cleaning appliance according to the present invention is provided with a seamless, all-time power supply, which enables an uninterrupted cleaning work by the user. Also, because the hybrid power system is able to receive AC power from a power socket as it becomes available, the cleaning appliance comprising such a hybrid power system is able to be driven by a constant power source. The user therefore does not have to concern about battery life during the cleaning process as that in a typical battery-driven only cleaning appliance. BRIEF DESCRIPTION OF FIGURES

[0024] The foregoing and further features of the present invention will be apparent from the following description of preferred embodiments which are provided by way of example only in connection with the accompanying figures, of which:

[0025] Fig. 1 is a perspective view of a typical upright suction cleaner in the art.

[0026] Fig. 2 shows a schematic diagram of the hybrid power supply system according to a first embodiment of the present invention

[0027] Fig. 3 illustrates the work flow of the method of hybrid power supply in the system as shown in Fig. 2.

[0028] Fig. 4 shows a schematic diagram of the hybrid power supply system according to a second embodiment of the present invention.

[0029] Fig. 5 shows a schematic diagram of the hybrid power supply system according to a third embodiment of the present invention.

[0030] Fig. 6 shows a schematic diagram of the hybrid power supply system according to a fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

[0032] As used herein and in the claims, "couple" or "connect" refers to electrical coupling or connection either directly or indirectly via one or more electrical means unless otherwise stated. [0033] As used herein and in the claims, "DC" refers to direct current, i.e. there is no alternation of the magnitude of current with respect to time. "AC" refers to alternative current, i.e. the magnitude of the current changes with respect to time.

[0034] Referring now to Fig. 2, the first embodiment of the present invention is a hybrid power supply system for a cleaning appliance such as suction cleaner. The suction cleaner contains a driving module for providing mechanical power for cleaning purposes. As shown in Fig. 2, such a driving module contains two DC motors 52, where one of them is a suction motor and the other one is a brush motor. The hybrid power supply system includes an AC power inlet 44 adapted to connect to an external power source 40 to receive AC power therefrom, an DC power source 60, an on-board DC charging device 50 connected to the DC power source 60, an AC/DC converter 48 connected to the AC power inlet 44 and configured to convert the AC power received by the AC power inlet 44 to DC power; and a switching device 57 connected to the DC power source 60 and the AC/DC converter 48. Both the DC power source 60 and the on-board DC charging device 50, as their names suggest, are embedded in the main body of the cleaning apparatus. The switching device 57 is configured to switch between a DC power output of the AC/DC converter 48 and a DC power output of the DC power source 60 for providing a system output to the driving module. In addition, there is a microcontroller 54 connected to the DC motors 52, the switching device 57, the DC power source 60, and the on-board DC charging device 50. The microcontroller 54 in combination with the switching device 57 is called a switching module herein. The microcontroller 54 connects to the on-board DC charging device 50 via a signal wire 63 and a temperature input line 61. The function of the microcontroller 54 as it relates to other components above in the hybrid power supply system will be described later.

[0035] External to the main body of the cleaning appliance, there is a power cord 45 adapted to connect the AC power inlet 44 to external power source 40, which in one embodiment is a home AC socket that provides mains voltage electricity. The power cord 45 has on its two ends two power plugs, namely the first plug 42 and the second plug 43. The first plug 42 is configured to engage with the AC power inlet 44 on the cleaning appliance. The second plug 43 is configured to engage with the home AC socket 40. Note that the form factors of the first plug 42 and the second plug 43 may be identical, but in some embodiments may not be identical, since the AC power inlet 44 may be designed with a dimension different from an ordinary AC wall socket.

[0036] Optionally, between the switching device 57 and the DC power source 60 there is arranged a first switch 51 for controlling open / close of the connection therebetween, so that when the first switch 51 is open, there is no DC power transmitted from the DC power source 60 to the switching device 57. Likewise, there can optionally be a second switch 53 arranged between the AC/DC converter 48 and the AC power inlet 44 so that when the second switch 53 is open, there is no AC electricity received by the AC/DC converter 48 from the AC power inlet 44. In one implementation the first switch 51 and the second switch 53 can be conveniently integrated into one single mechanical switch 46 for the user's actuation, as shown in Fig. 2. Such a mechanical switch 46 is also called a main switch. Alternatively, in other embodiments, the first switch 51 and the second switch 53 may be configured as two physically separated switches.

[0037] In the embodiment shown in Fig. 2, the on-board DC power source 60 is a rechargeable battery, which is consisted of two identical battery cells connected in series. The term "rechargeable battery" is used interchangeably with "DC power source" herein. Preferably, the rechargeable battery 60 is a lithium ion battery.

[0038] The switching device 57 as shown in Fig. 2 is consisted of a change-over relay 56 and a relay coil 58. The relay 56 is connected to the DC motors 52, the AC/DC converter 48 and the mechanical switch 46. The relay coil 58 is connected to the microcontroller 54 and is controlled by the micro-controller 54, and in turn the relay coil 58 drives the relay 56 to realize open / close of the circuit.

[0039] Now turning to the operation of the device described above, Figure 3 shows how the switching module of the hybrid power supply system according to the present invention may be automatically switched to use either the DC power from the on-board DC power source 60, or AC power from the AC power inlet 44. The hybrid power supply method of the cleaning appliance starts at step 80. When the cleaning appliance is powered on, for example by closing the mechanical switch 46 in Fig. 2, the microcontroller 54 senses presence of AC power at the AC power inlet 44. This may be implemented by connecting an input pin of the microcontroller 54 to an output of the on-board DC charging device 50 as shown in Fig. 2. When the AC power is present the AC/DC converter 48 will be able to generate a DC output, which can be detected by the microcontroller 54 through the on-board DC charging device 50 in step 82 as an indication that the cleaning appliances is now connected to a AC power source. Otherwise, the microcontroller 54 determines that AC power is not present at the AC power inlet 44.

[0040] In alternative embodiments, the microcontroller 54 may also has its input pin mentioned above directly connected to the AC/DC converter 48, without the on-board DC charging device 50 connected therebetween.

[0041] In Step 82 of Fig. 3, when the microcontroller 54 determines that there is no AC power available from the AC power inlet 44, the cleaning apparatus will have to work under the DC power mode and is switched to use DC power from the on-board DC power source 60 in Step 88. In particular, the microcontroller 54 sends out a control signal to the relay coil 58 in the switching device 57, and the relay coil 58 drives the relay 56 to connect poles that are connected to the DC motors 52 and the DC power source 60 respectively. The detailed operation principle of a change-over relay is well known in the art, and will not be discussed here. The DC power stored in the DC power source 60 like rechargeable batteries will be provided to DC motors 52. The DC power source 60 is designed such that its capacity and rated output current would be sufficient for the suction cleaner to work with a similar performance as that under AC work mode.

[0042] In the above DC power mode, the user does not have to connect the above-mentioned power cord 45 to the cleaning appliance since there is presumably no AC power available for supplying to the cleaning appliance. Without the limitation of the AC power cord on mobility of the cleaning appliance, the user is able to freely maneuver the cleaning appliance over the entire area of work. Also, the detachable power cord design allows the cleaning appliance to be used without the weight, hindrance or time associated with managing the power cord.

[0043] Returning back to Step 82 of Fig. 3, when the microcontroller 54 determines that there is indeed AC power available from the AC power inlet 44, the cleaning apparatus will work under the AC power mode and is switched to use AC power from the AC power inlet 44 in Step 86. In particular, the microcontroller 54 sends out a control signal to the relay coil 58 in the switching device 57, and the relay coil 58 drives the relay 56 to connect poles that are connected to the DC motors 52 and the output of AC/DC converter 48 respectively. Therefore, the DC power outputted by the AC/DC converter 48 after conversion will be provided to DC motors 52. Note that in the present invention since the AC/DC converter 48 is placed directly the AC power inlet 44 in circuit, and thus any AC power received from the AC power inlet 44 will be instantly converted to DC power. This configuration allows a consistent cleaning performance rendered by the cleaning appliance no matter whether it is working under the DC work mode or AC work mode. Further, as the AC/DC converter 48 is able to output DC power once the AC power plug is inserted into an AC socket, the microcontroller 54 may be configured to be powered by the output DC power from the AC/DC converter 48. In other implementations the microcontroller 54 may also be powered by the on-board DC power source 60 when AC power is not available, or always powered by the DC power source 60.

[0044] On the other hand, since the on-board DC charging device is directly connected to the AC/DC converter 48, the rechargeable battery 60 is automatically charged by the on-board DC charging device 50 whenever there is AC power received from AC power inlet 44. There is no user intervention required for the charging process to take place. Further, the microcontroller 54 and the DC power source 60 are configured with protective means. For example, the DC power source 60 contains an internal temperature sensor (not shown), which monitors the temperature of battery cells in the DC power source 60. Such temperature value after measurement would be transmitted to the microcontroller 54. When the temperature of the battery cells exceeding a predetermined value is detected by the microcontroller 54 via the above mentioned temperature input line 61, the microcontroller 54 controlling the on-board DC charging device 50 to deactivate, thereby stop further charging the DC power source 60. In addition, the DC power source 60 is able to measure the instantaneous value of the battery cell current and voltage. If the current or voltage exceeding a predetermined value is detected by the microcontroller 54 via the above mentioned signal wire 63, the microcontroller 54 again controls the on-board DC charging device 50 to deactivate in order to protect the battery cells.

[0045] In the above embodiment the rechargeable battery 60 is permanently encased in the main body of the cleaning appliance, in particular within its housing. Such a configuration provides many advantages, for example it saves the need of multiple enclosure materials for the battery, which reduces cost of manufacturing and also the weight of the whole cleaning appliance. Embedded battery also prevents unintended access to the battery by the user. As a consequence, the user does not have to manage or even consider about the existence of the battery when it is an embedded component and fully automatic operation is provided. For a similar reason, the embedded on-board DC charging device 50 also allows a convenient use of the cleaning appliance as the user does not have to take care of a separate battery charger which is a separate piece external to the cleaning appliance. Also the embedded DC charger allows the charging process to happen automatically if the cleaning appliance is connected to AC power source as described above. A single power cord would be sufficient for both running the cleaning appliance in work mode, and also for charging the embedded battery.

[0046] In one embodiment, the microcontroller 54 is also able to monitor the working status of either one or both DC motors 52. In particular, microcontroller 54 measures real-time value of current through the DC motors 52. When the current measured for one motor exceeds a predetermined value for a given time (e.g. in a likely situation of motor stall due to external disturbance), the microcontroller 54 would determine an abnormal condition of the motor, and thus takes protective measures such as stop providing DC power to the motor from the AC/DC converter or the on-board power source.

[0047] Turning now to Fig. 4, in another embodiment of the present invention a cleaning appliance in general similar to that of Fig. 2 is illustrated. The only difference here is that the AC power cord 145 in this embodiment of Fig. 4 is permanently mounted on the cleaning appliance to the AC power inlet 144, so that the power cord 145 is not detachable. For example, the power cord may reside in a cord rewind in the cleaning appliance, or one end of the power may be permanently fixed to the main body of the cleaning appliance. Such configurations provide the benefits that there is no chance of the power cord being mislaid by the user. Also, there is no requirement for a separate storage device or area for the power cord when it is detached and separated from the main body of the cleaning appliance.

[0048] Turning now to Fig. 5, in another embodiment of the present invention a cleaning appliance in general similar to that of Fig. 2 is illustrated. The only difference here is that the DC power source 260 now becomes detachable from the main body of the cleaning appliance. The DC power source 260 in this embodiment is a separate battery pack which is equipped with a plug or socket 264. On the other side, the main body of the cleaning appliance is also equipped with a corresponding socket or plug 262 which match the plug or socket 264 on the DC power source 260. The main body of the cleaning appliance may also be formed to include a recess or support for receiving the DC power source 260. Once the DC power source 260 is attached to the main body of the cleaning appliance, and when the socket or plug 262 on the main body is engaged with the plug or socket 264 on the DC power source 260, DC power stored in the DC power source 260 is supplied to the cleaning appliance for operation. This configuration of detachable battery provides convenience when it is needed to conduct a battery replacement or service maintenance to the battery.

[0049] Turning now to Fig. 6, where the hybrid power supply system shown herein differs from that in Fig. 2 in the way that the automatic switching module (e.g. change-over relay) is replaced by a manually switchable module 366 in Fig. 6. The manually switchable module 366, also called a user-controllable switch, is coupled to the main switch 346, which in turn connects to the DC power source 360. The user-controllable switch 366 also connects to the AC/DC converter 348 and the driving module containing two DC motors 352. The user-controllable switch 366 is capable of being moved between at least a first position and a second position (not shown). When the user-controllable switch 366 is moved to the first position, the DC motors 352 are electrically isolated from the DC power source 360, and the DC power output from the AC/DC converter 348 is capable of being provided to DC motors 352. When the user-controllable switch capable 366 is in the second position, the AC/DC converter 348 is electrically isolated from the DC motors 352, and the DC power output from the DC power source 360 is capable of being provided to the DC motors 352. The first position described above corresponds to the AC work mode of the cleaning appliance, and the second position corresponds to the DC work mode of the cleaning appliance.

[0050] In a more preferred embodiment, the user-controllable switch 366 is adapted to be moved into a third position different from the first position and the second position mentioned above. When the user-controllable switch 366 is in the third position, the DC motors 352 are electrically isolated from both the DC power source 360 and the AC/DC converter 348. In other word the DC motors 352 in this mode is not powered, and the cleaning appliance enters a stand-by or sleeping mode. In the same time, the AC/DC converter 348 is connected to the on-board DC charging device so if AC power is received by the AC/DC converter 348, the DC power output of the AC/DC converter 348 is provided to the on-board DC charging device 350 for charging the DC power source 360.

[0051] While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only exemplary embodiments have been shown and described and do not limit the scope of the invention in any manner. It can be appreciated that any of the features described herein may be used with any embodiment. The illustrative embodiments are not exclusive of each other or of other embodiments not recited herein. Accordingly, the invention also provides embodiments that comprise combinations of one or more of the illustrative embodiments described above. Modifications and variations of the invention as herein set forth can be made without departing from the spirit and scope thereof, and, therefore, only such limitations should be imposed as are indicated by the appended claims.

[0052] For example, although in the specific embodiments described above the cleaning appliance is an upright suction cleaner, a skilled person would appreciate the same hybrid power supply system / method may be equally applied to other types of cleaning appliances, for example canister cleaner, stick vacuums, steam cleaners, hard floor cleaners, etc.

[0053] In the embodiments described above, the rechargeable battery used in the hybrid power supply system is a lithium battery. However, those skilled in the art would no doubt appreciate that other types of batteries may also serve the same purpose as long as they can provide desired output characteristics. Such batteries include but not limit to lead-acid battery, nickel-cadmium battery and nickel metal hydride battery.

[0054] Also, in the embodiments described above the suction cleaner contains two DC motors, one for vacuum generation and the other one for brush movement. However, one skilled in the art would realize that in other types of cleaning appliances such as those containing only one DC motor, or one DC motor with one universal or AC motor, the present invention as described may equally be applied, without departing from the spirit and scope thereof.