Patent Description:
A vacuum cleaner is an apparatus that uses a motor/fan unit to create a partial vacuum in order to obtain an air flow for sucking up dust and dirt from surfaces, such as floors, carpets, furniture, curtains, and the like. The motor/fan unit usually comprises a centrifugal fan and an electric motor configured to power, i.e. rotate, the centrifugal fan.

In general, some problems and requirements exist when designing vacuum cleaners. One example is cleaning efficiency. Users of vacuum cleaners expect a high cleaning efficiency to achieve a good cleaning result with little effort. The cleaning efficiency partly depends on the airflow rate, an in turn, the airflow rate depends on the magnitude of the partial vacuum created by the motor/fan unit. In many vacuum cleaners, the power of the motor/fan unit can be regulated. Thereby, a user can reduce the power when wanting to clean sensitive and soft surfaces, such as curtains and carpets, and can increase the power when wanting to clean harder surfaces, such as floor surfaces.

Another important requirement of vacuum cleaners is energy efficiency. In a vacuum cleaner, the energy efficiency can be defined as the ratio between the useful output in the form of airflow and the input of electrical energy. A problem associated with vacuum cleaners is that the energy efficiency of the vacuum cleaner drops significantly at higher power levels of the motor/fan unit. Likewise, the energy efficiency of the vacuum cleaner drops significantly at lower power levels of the motor/fan unit. That is, when the motor/fan unit of a vacuum cleaner is operated at higher power levels, as well as at lower power levels, the ratio between the useful output in the form of airflow and the input of electrical energy drops significantly. In other words, many motor/fan units have a narrow operational range in which the vacuum cleaner can be operating in an efficient manner.

Document <CIT> discloses a vacuum cleaner comprising a first vacuum cleaner unit and a second vacuum cleaner unit. The apparatus comprises a first motor/fan unit and a first dust separation unit arranged in the first vacuum cleaner unit. The first motor/fan unit is configured to generate an airflow through an airflow path of the first vacuum cleaner unit to the first dust separation unit.

Furthermore, the apparatus comprises a second motor/fan unit and a second dust separation unit arranged in the second vacuum cleaner unit and wherein the second motor/fan unit is configured to generate an airflow from a suction inlet of the second vacuum cleaner unit to the second dust separation unit.

Other important requirements of vacuum cleaners are flexibility and usability. Many vacuum cleaners can be bulky and can be difficult to use when cleaning confined spaces and objects at higher places, such as curtains, cabinets, and the like.

Furthermore, generally, on today's consumer market, it is an advantage if products, such as vacuum cleaners and associated components, systems, and arrangements, have conditions and/or characteristics suitable for being manufactured and assembled in a cost-efficient manner.

According to a first aspect of the invention, the object is achieved by a vacuum cleaner apparatus comprising a first vacuum cleaner unit and a second vacuum cleaner unit. The apparatus comprises a first motor/fan unit and a first dust separation unit arranged in the first vacuum cleaner unit. The first motor/fan unit is configured to generate an airflow through an airflow path of the first vacuum cleaner unit to the first dust separation unit. The apparatus comprises a second motor/fan unit and a second dust separation unit arranged in the second vacuum cleaner unit. The second motor/fan unit is configured to generate an airflow from a suction inlet of the second vacuum cleaner unit to the second dust separation unit. The apparatus comprises a connection interface configured to removably connect the suction inlet of the second vacuum cleaner unit to the airflow path of the first vacuum cleaner unit. The apparatus comprises a control arrangement capable of operating the apparatus in a cooperative cleaning mode in which the first and second motor/fan units are operated simultaneously.

Since the apparatus comprises the connection interface configured to removably connect the suction inlet of the second vacuum cleaner unit to the airflow path of the first vacuum cleaner unit and the control arrangement capable of operating the first and second motor/fan units simultaneously, a vacuum cleaner apparatus is provided having conditions for a significantly widened operational range in which the vacuum cleaner apparatus can be operated in an efficient manner. This is because the first and second motor/fan units can operate in a parallel manner when the apparatus is operating in the cooperative cleaning mode. That is, in the cooperative cleaning mode, the first and second motor/fan units can operate in a parallel manner in which the partial vacuum created by the respective first and second motor/fan units together causes an airflow at a suction inlet of the first vacuum cleaner in a cooperative manner. Moreover, dust entering the suction inlet of the first vacuum cleaner can be collected in the first dust separation unit as well as in the second dust separation unit which can increase the total dust accumulating capacity of the apparatus.

As a further result of these features, a vacuum cleaner apparatus is provided having conditions for generating high airflow rates at a suction inlet of the first vacuum cleaner unit in an energy efficient manner. In other words, a vacuum cleaner apparatus is provided having conditions for providing high cleaning efficiency while consuming a low amount of electrical energy.

In addition, a more versatile and flexible vacuum cleaner apparatus is provided having conditions for varying the power in a wider range so as to obtain a wanted airflow rate at minimum energy consumption. Furthermore, conditions are provided for utilizing smaller motor/fan units in the apparatus and still obtain a high airflow rate when operating the apparatus in the cooperative cleaning mode.

Accordingly, a vacuum cleaner apparatus is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

Optionally, the second vacuum cleaner unit is operable as a vacuum cleaner in isolation of the first vacuum cleaner unit. Thereby, a more versatile and flexible vacuum cleaner apparatus is provided in which the second vacuum cleaner unit can be removed from the first vacuum cleaner unit to be used as a vacuum cleaner in isolation of the first vacuum cleaner unit.

Optionally, the connection interface further comprises a holding arrangement configured to hold the second vacuum cleaner unit relative to the first vacuum cleaner unit when the suction inlet of the second vacuum cleaner unit is connected to the airflow path of the first vacuum cleaner unit. Thereby, a user-friendly vacuum cleaner apparatus is provided in which the second vacuum cleaner unit can be held relative to the first vacuum cleaner unit during use of the apparatus as well as during storage of the apparatus.

Optionally, the second vacuum cleaner unit comprises a battery unit configured to power the second motor/fan unit, at least when the suction inlet of the second vacuum cleaner unit is removed from the airflow path of the first vacuum cleaner unit. Thereby, a user-friendly vacuum cleaner apparatus is provided where the second vacuum cleaner unit can be operated in isolation of the first vacuum cleaner unit without using a cord connected to a socket.

Optionally, the connection interface comprises electrical connections configured to transfer electricity between the first and second vacuum cleaner units. Thereby, the vacuum cleaner apparatus provides conditions for a transfer of energy and/or signals between the first and second vacuum cleaner units.

Optionally, the battery unit of the second vacuum cleaner unit is rechargeable and is configured to be charged using electricity supplied via the electrical connections. Thereby, a user-friendly vacuum cleaner apparatus is provided where the battery unit of the second vacuum cleaner can be charged simply by connecting the second vacuum cleaner unit to the connection interface.

Optionally, the second motor/fan unit is differently configured than the first motor/fan unit. According to these embodiments, the second motor/fan unit may be differently configured than the first motor/fan unit regarding structural aspects and/or regarding efficient working point, i.e. the operational point at which the motor/fan unit operates most efficiently. The structural aspects may include one or more of type of motor, size of motor, type of fan, and size of fan. Since according to these embodiments, the second motor/fan unit is differently configured than the first motor/fan unit, and due to the parallel arrangement of the motor/fan units, a vacuum cleaner apparatus is provided having conditions for a further widened operational range in which the vacuum cleaner apparatus can be operated in an efficient manner.

Optionally, the second motor/fan unit comprises a fan and a brushless motor configured to power the fan. Thereby, a vacuum cleaner apparatus can be provided having conditions for a further widened operational range in which the vacuum cleaner apparatus can be operated in an efficient manner. This is because a motor/fan unit comprising a brushless motor usually has a high ability to quickly generate high vacuum levels.

Optionally, the first motor/fan unit comprises a fan and a brushed motor configured to power the fan. According to these embodiments, the brushed motor may be a so called canister motor. By combining a brushed motor and a brushless motor, an even further widened operational range can be obtained in which the vacuum cleaner apparatus can be operated in an efficient manner. This is because the brushed motor usually has a higher ability to generate high airflow rates whereas the brushless motor usually has a higher ability to quickly generate high vacuum levels.

Optionally, the second vacuum cleaner unit is smaller in size than the first vacuum cleaner unit. Thereby, an even more versatile and flexible vacuum cleaner apparatus is provided, wherein the second vacuum cleaner for example can be used in isolation of the first vacuum cleaner unit when wanting to quickly clean an area, when wanting to clean confined spaces, and/or when wanting to clean objects at higher places, such as curtains, cabinets, and the like.

Optionally, the control arrangement comprises a first electronic control unit arranged in the second vacuum cleaner unit, and wherein the first electronic control unit is configured to control the power of the second motor/fan unit during operation of the second vacuum cleaner unit. Since the first electronic control unit is arranged in the second vacuum cleaner unit, a vacuum cleaner apparatus is provided in which the first electronic control unit can be utilized for controlling the second motor/fan unit when the second vacuum cleaner unit is used in isolation of the first vacuum cleaner unit.

Optionally, the first electronic control unit is configured to control the power of the first and second motor/fan units when the control arrangement is operating in the cooperative cleaning mode. Since the first electronic control unit is arranged in the second vacuum cleaner unit, a vacuum cleaner apparatus is provided in which the first electronic control unit can be utilized for controlling the second motor/fan unit when the second vacuum cleaner unit is used in isolation of the first vacuum cleaner unit and in which the first electronic control unit can be utilized for controlling the first and second motor/fan units when operating in the cooperative cleaning mode. In this manner, the need for an electronic control unit in the first vacuum cleaner unit is circumvented. As a further result thereof, a vacuum cleaner apparatus is provided having conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner.

Optionally, the control arrangement comprises a second electronic control unit arranged in the first vacuum cleaner unit, and wherein the second electronic control unit is configured to control the power of the first and second motor/fan units when the control arrangement is operating in the cooperative cleaning mode. Thereby, conditions are provided for a small sized and low weight second vacuum cleaner unit. This because the first electronic control unit in the second vacuum cleaner unit can be made less complex and smaller in size.

Optionally, the first vacuum cleaner unit is operable as a vacuum cleaner in isolation of the second vacuum cleaner unit, and wherein the second electronic control unit is configured to control the power of the first motor/fan unit when the second vacuum cleaner unit is removed from the first vacuum cleaner unit. Thereby, a still more versatile and flexible vacuum cleaner apparatus is provided in which the first vacuum cleaner unit can be used as a vacuum cleaner in isolation of the first vacuum cleaner unit.

Optionally, the connection interface comprises electrical connections configured operably connect the first and second electronic control units. Thereby, an apparatus is provided having conditions for operating in the cooperative cleaning mode in an efficient and reliable manner while conditions are provided for operating the first and second vacuum cleaner units in independent manners when the second vacuum cleaner unit is removed from the first vacuum cleaner unit.

Optionally, the connection interface comprises a closure member movably arranged between an open position, in which the closure member opens an aperture between the airflow path of the first vacuum cleaner unit and the suction inlet of the second vacuum cleaner unit, and a closed position in which the closure member closes the aperture. Thereby, the first vacuum cleaner unit has conditions for operating more efficiently in isolation of the second vacuum cleaner unit while allowing an airflow from the airflow path of the first vacuum cleaner unit to the suction inlet of the second vacuum cleaner unit during operation in the cooperative cleaning mode.

Optionally, the closure member is arranged on the first vacuum cleaner unit. Thereby, the first vacuum cleaner unit can operate more efficiently in isolation of the second vacuum cleaner unit while allowing an airflow from the airflow path of the first vacuum cleaner unit to the suction inlet of the second vacuum cleaner unit during operation in the cooperative cleaning mode.

Optionally, the closure member is configured to assume the closed position when the suction inlet is removed from the airflow path. Thereby, a more user-friendly vacuum cleaner apparatus is provided facilitating use of the first vacuum cleaner unit in isolation of the second vacuum cleaner.

Optionally, the control arrangement is capable of operating the apparatus in a non-cooperative cleaning mode in which only the first motor/fan unit is operated when the suction inlet is connected to the airflow path, and wherein the closure member is configured to assume the closed position when the apparatus is operating in the non-cooperative cleaning mode. Thereby, a reverse flow of air is avoided through the second vacuum cleaner unit when operating in the non-cooperative cleaning mode. Moreover, since the control arrangement is capable of operating the apparatus in the non-cooperative cleaning mode, an even more flexible and versatile vacuum cleaner apparatus is provided capable of operating in a still wider operational range.

Optionally, the connection interface comprises a sealing configured to seal an area around an aperture between the airflow path of the first vacuum cleaner unit and the suction inlet of the second vacuum cleaner unit when the suction inlet is connected to the airflow path. Thereby, leakage of ambient air is avoided into the suction inlet of the second vacuum cleaner unit when the suction inlet is connected to the airflow path. As a further result thereof, a high operational efficiency of the vacuum cleaner apparatus can be ensured.

Optionally, the second vacuum cleaner unit is a hand-held vacuum cleaner. Thereby, a versatile and flexible vacuum cleaner apparatus is provided, wherein the second vacuum cleaner for example may be used in isolation of the first vacuum cleaner unit when wanting to quickly clean an area, when wanting to clean confined spaces, and/or when wanting to clean objects at higher places, such as curtains, cabinets, and the like.

Optionally, the first vacuum cleaner unit is a stick-type vacuum cleaner. Thereby, a versatile and flexible vacuum cleaner apparatus is provided, wherein the first vacuum cleaner for example may be used in isolation of the second vacuum cleaner unit when wanting to clean larger areas, such as floor surfaces.

According to a second aspect of the invention, the object is achieved by a vacuum cleaner unit comprising a dust separation unit, an airflow path, and a motor/fan unit configured to generate an airflow through the airflow path to the first dust separation unit. The vacuum cleaner unit comprises a connection interface configured to removably connect a suction inlet of a second vacuum cleaner unit to the airflow path. The motor/fan unit is operably connected to the connection interface allowing for an operation in a cooperative cleaning mode in which the motor/fan unit of the vacuum cleaner unit and a motor/fan unit of the second vacuum cleaner unit are operated simultaneously.

Since the vacuum cleaner unit comprises the connection interface allowing for an operation in a cooperative cleaning mode in which the motor/fan unit of the vacuum cleaner unit and a motor/fan unit of the second vacuum cleaner unit are operated simultaneously, a vacuum cleaner unit is provided having conditions for a significantly widened operational range in which the vacuum cleaner apparatus can be operated in an efficient manner. This is because the first and second motor/fan units can operate in a parallel manner when operating in the cooperative cleaning mode. That is, in the cooperative cleaning mode, the first and second motor/fan units can operate in a parallel manner in which the partial vacuum created by the respective first and second motor/fan units together causes an airflow at a suction inlet of the first vacuum cleaner in a cooperative manner.

As a further result of these features, a vacuum cleaner unit is provided having conditions for generating high airflow rates at a suction inlet of the vacuum cleaner unit in an energy efficient manner. In other words, a vacuum cleaner unit is provided having conditions for providing high cleaning efficiency while consuming a low amount of electrical energy.

In addition, a more versatile and flexible vacuum cleaner unit is provided having conditions for varying the power in a wider range so as to obtain a wanted airflow rate at minimum energy consumption. Furthermore, conditions are provided for utilizing a smaller motor/fan unit in the vacuum cleaner unit and still obtain a high airflow rate when operating the apparatus in the cooperative cleaning mode.

Accordingly, a vacuum cleaner unit is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

According to a third aspect of the invention, the object is achieved by a method of operating a vacuum cleaner apparatus comprising a first vacuum cleaner unit and a second vacuum cleaner unit. The apparatus comprises a first motor/fan unit and a first dust separation unit arranged in the first vacuum cleaner unit, wherein the first motor/fan unit is configured to generate an airflow through an airflow path of the first vacuum cleaner unit to the first dust separation unit. The apparatus further comprises a second motor/fan unit and a second dust separation unit arranged in the second vacuum cleaner unit, wherein the second motor/fan unit is configured to generate an airflow from a suction inlet of the second vacuum cleaner unit to the second dust separation unit. The apparatus further comprises a connection interface configured to removably connect the suction inlet of the second vacuum cleaner unit to the airflow path of the first vacuum cleaner unit. The method comprises the step of:.

Since the method comprises the step of operating the motor/fan units of the first and second vacuum cleaner units simultaneously, the method provides conditions for significantly widening the operational range in which the vacuum cleaner apparatus can be operated in an efficient manner. This is because the first and second motor/fan units can operate in a parallel manner during the step of operating the motor/fan units of the first and second vacuum cleaner units simultaneously. That is, the first and second motor/fan units can operate in a parallel manner in which the partial vacuum created by the respective first and second motor/fan units together causes an airflow at a suction inlet of the first vacuum cleaner in a cooperative manner. Moreover, dust entering the suction inlet of the first vacuum cleaner can be collected in the first dust separation unit as well as in the second dust separation unit which can increase the total dust accumulating capacity of the apparatus.

As a further result of these features, a method is provided having conditions for generating high airflow rates at a suction inlet of the first vacuum cleaner unit in an energy efficient manner. In other words, a method is provided having conditions for providing high cleaning efficiency while consuming a low amount of electrical energy. Moreover, the method provides conditions for varying the power in a wider range so as to obtain a wanted airflow rate at minimum energy consumption. Furthermore, conditions are provided for utilizing smaller motor/fan units in the apparatus and still obtain a high airflow rate when operating the apparatus in the cooperative cleaning mode.

Accordingly, a method is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

Optionally, the step of operating the motor/fan units of the first and second vacuum cleaner units simultaneously comprises the step of:.

Thereby, the method provides conditions for further widening the operational range in which the vacuum cleaner apparatus can be operated in an efficient manner in order to provide high cleaning efficiency while consuming a low amount of electrical energy.

<FIG> schematically illustrates a vacuum cleaner apparatus <NUM> according to some embodiments. The vacuum cleaner apparatus <NUM> is in some places herein referred to as "the apparatus <NUM>" for reasons of brevity and clarity. The vacuum cleaner apparatus <NUM> comprises a first vacuum cleaner unit <NUM> and a second vacuum cleaner unit <NUM>. According to the illustrated embodiments, the second vacuum cleaner unit <NUM> is smaller in size than the first vacuum cleaner unit <NUM>. In more detail, according to the illustrated embodiments, the first vacuum cleaner unit <NUM> is a stick-type vacuum cleaner and the second vacuum cleaner unit <NUM> is a hand-held vacuum cleaner. According to further embodiments of the present disclosure, the first vacuum cleaner unit <NUM> may be another type of vacuum cleaner, such as a hand-held vacuum cleaner, a canister vacuum cleaner, a robotic vacuum cleaner, or a central vacuum cleaner. Likewise, according to further embodiments of the present disclosure, the second vacuum cleaner unit <NUM> may be another type of vacuum cleaner, such as a stick-type vacuum, a canister vacuum cleaner, a robotic vacuum cleaner, or a central vacuum cleaner. In embodiments the type of the first and second vacuum cleaner can be mixed. As understood from the herein described, the first vacuum cleaner unit <NUM> and the second vacuum cleaner unit <NUM> are together referred to as a vacuum cleaner apparatus <NUM>. This is because of the fact that the vacuum cleaner apparatus <NUM> can be used in a cooperative cleaning mode in which the first and second vacuum cleaner units <NUM>, <NUM> cooperates, as is further explained herein. The vacuum cleaner apparatus <NUM> may also be referred to as a vacuum cleaner system <NUM>.

Therefore, throughout this disclosure, the wording "vacuum cleaner apparatus <NUM>" may be replaced by the wording "vacuum cleaner system <NUM>".

The apparatus <NUM> comprises a first motor/fan unit <NUM> and a first dust separation unit <NUM>. Each of the first motor/fan unit <NUM> and the first dust separation unit <NUM> is arranged in the first vacuum cleaner unit <NUM>. The first motor/fan unit <NUM> is configured to generate an airflow from a suction inlet <NUM> of the first vacuum cleaner unit <NUM> through an airflow path <NUM> of the first vacuum cleaner unit <NUM> to the first dust separation unit <NUM>. The first dust separation unit <NUM> is configured to separate dust from air flowing through the first dust separation unit <NUM>. According to the illustrated embodiments, the first dust separation unit <NUM> comprises a cyclone separator. According further embodiments, the first dust separation unit <NUM> may comprise another type of component for separating dust, such as a filter, a dust bag, or the like.

The apparatus <NUM> comprises a second motor/fan unit <NUM>' and a second dust separation unit <NUM>'. Each of the second motor/fan unit <NUM>' and the second dust separation unit <NUM>' is arranged in the second vacuum cleaner unit <NUM>. The first and second motor/fan units <NUM>, <NUM>' each comprises a fan <NUM>, <NUM>' and an electric motor <NUM>, <NUM>' configured to power/rotate the fan <NUM>, <NUM>'. Each of the fans <NUM>, <NUM>' may comprise a centrifugal fan. The second motor/fan unit <NUM>' is configured to generate an airflow from a suction inlet <NUM>' of the second vacuum cleaner unit <NUM> to the second dust separation unit <NUM>' via an airflow path <NUM>' of the second vacuum cleaner unit <NUM>. According to the illustrated embodiments, the second dust separation unit <NUM>' comprises a filter. According further embodiments, the second dust separation unit <NUM>' may comprise another type of component for separating dust, such as a cyclone separator, a dust bag, or the like.

As understood from the above, the suction inlet <NUM>, the first motor/fan unit <NUM>, the first dust separation unit <NUM>, and the airflow path <NUM> is comprised in the first vacuum cleaner unit <NUM>. The suction inlet <NUM> and the airflow path <NUM> of the first vacuum cleaner unit <NUM> may also be referred to as a first suction inlet <NUM> and a first airflow path <NUM> of the vacuum cleaner apparatus <NUM>. Likewise, the suction inlet <NUM>', the second motor/fan unit <NUM>', the second dust separation unit <NUM>', and the airflow path <NUM>' is comprised in the second vacuum cleaner unit <NUM>. The suction inlet <NUM>' and the airflow path <NUM>' of the second vacuum cleaner unit <NUM> may also be referred to as a second suction inlet <NUM>' and a second airflow path <NUM>' of the vacuum cleaner apparatus <NUM>.

The apparatus <NUM> comprises a connection interface <NUM>. The connection interface <NUM> is configured to removably connect the suction inlet <NUM>' of the second vacuum cleaner unit <NUM> to the airflow path <NUM> of the first vacuum cleaner unit <NUM>. In <FIG>, the vacuum cleaner apparatus <NUM> is illustrated in a connected state in which the suction inlet <NUM>' of the second vacuum cleaner unit <NUM> is connected to the airflow path <NUM> of the first vacuum cleaner unit <NUM>. Moreover, as is further explained herein, the apparatus <NUM> comprises a control arrangement <NUM> capable of operating the apparatus <NUM> in a cooperative cleaning mode in which the first and second motor/fan units <NUM>, <NUM>' are operated simultaneously. The connection interface <NUM> thus allows for an operation in the cooperative cleaning mode in which the motor/fan unit <NUM> of the vacuum cleaner unit <NUM> and the motor/fan unit <NUM>' of the second vacuum cleaner unit <NUM> are operated simultaneously. Thereby, a versatile and flexible vacuum cleaner apparatus <NUM> is provided having conditions for generating high airflow rates at the suction inlet <NUM> of the first vacuum cleaner unit <NUM> in an energy efficient manner, as is further explained herein.

According to the illustrated embodiments, the connection interface <NUM> comprises a closure member <NUM> and an aperture <NUM>. According to the illustrated embodiments, the closure member <NUM> and the aperture <NUM> are arranged on the first vacuum cleaner unit <NUM>. The aperture <NUM> is in fluid communication with the airflow path <NUM> of the first vacuum cleaner unit <NUM>. The closure member <NUM> is movably arranged between an open position, in which the closure member <NUM> opens the aperture <NUM>, and a closed position in which the closure member <NUM> closes the aperture <NUM>. In <FIG>, the closure member <NUM> is illustrated in the open position. The suction inlet <NUM>' of the second vacuum cleaner unit <NUM> is connected to the airflow path <NUM> of the first vacuum cleaner unit <NUM> via the aperture <NUM> when the apparatus <NUM> is in the connected state as is illustrated in <FIG>. According to some embodiments, the closure member <NUM> is configured to assume the open position when the apparatus <NUM> is in the connected state, i.e. when the suction inlet <NUM>' of the second vacuum cleaner unit <NUM> is connected to the airflow path <NUM> of the first vacuum cleaner unit <NUM> via the aperture <NUM>.

According to some embodiments, the closure member <NUM> is configured such that the position of the closure member <NUM> is controlled by the difference in air pressure on either side of the closure member <NUM>. As can be seen in <FIG>, and as is understood from the above described, the closure member <NUM> is arranged between the airflow path <NUM> of the first vacuum cleaner unit <NUM> and the airflow path <NUM>' of the second vacuum cleaner unit <NUM> when the apparatus <NUM> is in the connected state. In more detail, according to these embodiments, the closure member <NUM> may be configured to assume the open position when the air pressure in the airflow path <NUM>' of the second vacuum cleaner unit <NUM> is lower than the air pressure in the airflow path <NUM> of the first vacuum cleaner unit <NUM>. According to these embodiments, the closure member <NUM> may be spring biased in a direction towards the airflow path <NUM> of the first vacuum cleaner unit <NUM>. In this manner, the closure member <NUM> can be displaced to the open position in an automatic manner when operation of the second motor/fan unit <NUM>' causes the air pressure at the airflow path <NUM>' of the second vacuum cleaner unit <NUM> to become lower than the air pressure at the airflow path <NUM> of the first vacuum cleaner unit <NUM>.

According to some embodiments, the control arrangement <NUM> is capable of operating the apparatus <NUM> in a non-cooperative cleaning mode in which only the first motor/fan unit <NUM> is operated when the suction inlet <NUM>' is connected to the airflow path <NUM>. Thus, in the above described embodiments, the closure member <NUM> will assume the closed position when the apparatus <NUM> is operating in the non-cooperative cleaning mode. This because the operation of the first motor/fan unit <NUM> in the non-cooperative cleaning mode will cause the air pressure at the airflow path <NUM> of the first vacuum cleaner unit <NUM> to become lower than the air pressure at the airflow path <NUM>' of the second vacuum cleaner unit <NUM>. Thereby, a reverse flow of air is avoided through the second vacuum cleaner unit <NUM> into the airflow path <NUM> of the first vacuum cleaner unit <NUM> during operation in the non-cooperative cleaning mode.

In the cooperative cleaning mode, each of the first and second motor/fan units <NUM>, <NUM>' generates a partial vacuum. The partial vacuum generated by the first motor/fan unit <NUM> is transferred to the suction inlet <NUM> of the first vacuum cleaner unit <NUM> via the first dust separation unit <NUM> and the airflow path <NUM> of the first vacuum cleaner unit <NUM>. The partial vacuum generated by the second motor/fan unit <NUM>' is transferred to the suction inlet <NUM> of the first vacuum cleaner unit <NUM> via the second dust separation unit <NUM>', the airflow path <NUM>' of the second vacuum cleaner unit <NUM>, the aperture <NUM>, and the airflow path <NUM> of the first vacuum cleaner unit <NUM>. Accordingly, dust entering the suction inlet <NUM> of the first vacuum cleaner unit <NUM> is separated by the first dust separation unit <NUM> as well as by the second dust separation unit <NUM>'. In this manner, the total dust accumulating capability of the apparatus <NUM> is enlarged.

According to the illustrated embodiments, the connection interface <NUM> comprises a sealing <NUM>. The sealing <NUM> is configured to seal an area around the aperture <NUM> between the airflow path <NUM> of the first vacuum cleaner unit <NUM> and the suction inlet <NUM>' of the second vacuum cleaner unit <NUM> when the suction inlet <NUM>' is connected to the airflow path <NUM>. The sealing <NUM> may comprise a lip seal or another type of soft sealing.

According to the illustrated embodiments, the connection interface <NUM> comprises a holding arrangement <NUM>. The holding arrangement <NUM> is configured to hold the second vacuum cleaner unit <NUM> relative to the first vacuum cleaner unit <NUM> when the suction inlet <NUM>' of the second vacuum cleaner unit <NUM> is connected to the airflow path <NUM> of the first vacuum cleaner unit <NUM>. The holding arrangement <NUM> may comprise a mechanical holding arrangement <NUM>, such as a slide-fit arrangement, a snap-fit arrangement, or the like. As an alternative, or in addition, the holding arrangement <NUM> may comprise a magnetic holding arrangement. Moreover, according to some embodiments, the sealing <NUM> and/or the aperture <NUM> may form part of the holding arrangement <NUM>.

According to the illustrated embodiments, the second vacuum cleaner unit <NUM> is operable as a vacuum cleaner in isolation of the first vacuum cleaner unit <NUM>. Likewise, the first vacuum cleaner unit <NUM> is operable as a vacuum cleaner in isolation of the second vacuum cleaner unit <NUM>. Therefore, the first vacuum cleaner unit <NUM> may also be referred to as a first vacuum cleaner <NUM> and the second vacuum cleaner unit <NUM> may also be referred to as a second vacuum cleaner <NUM>. According to further embodiments, only the second vacuum cleaner unit <NUM> is operable as a vacuum cleaner in isolation of the first vacuum cleaner unit <NUM>, as is further explained herein.

<FIG> illustrates the vacuum cleaner apparatus <NUM> according to the embodiments illustrated in <FIG> in a disconnected state, i.e. in a state in which the suction inlet <NUM>' of the second vacuum cleaner unit <NUM> is removed from the airflow path <NUM> of the first vacuum cleaner unit <NUM>. In <FIG>, the closure member <NUM> is illustrated in the closed state. As a result, the aperture <NUM> is closed. According to some embodiments, the closure member <NUM> is configured to assume the closed position when the suction inlet <NUM>' of the second vacuum cleaner unit <NUM> is removed from the airflow path <NUM> of the first vacuum cleaner unit <NUM>. This may be achieved by the closure member <NUM> being spring biased in a direction towards the airflow path <NUM> of the first vacuum cleaner unit <NUM>. As an alternative, or in addition, the closure member <NUM> may be manually operated allowing a user to manually move the closure member <NUM> between the open and closed positions.

According to the embodiments illustrated in <FIG> and <FIG>, the second vacuum cleaner unit <NUM> comprises a battery unit <NUM>'. The battery unit <NUM>' is configured to power the second motor/fan unit <NUM>', at least when the suction inlet <NUM>' of the second vacuum cleaner unit <NUM> is removed from the airflow path <NUM> of the first vacuum cleaner unit <NUM>, as is illustrated in <FIG>.

According to the illustrated embodiments, the control arrangement <NUM> of the vacuum cleaner apparatus <NUM> comprises a first electronic control unit <NUM>' arranged in the second vacuum cleaner unit <NUM>. The first electronic control unit <NUM>' is configured to control the power of the second motor/fan unit <NUM>' during operation of the second vacuum cleaner unit <NUM>. The second vacuum cleaner unit <NUM> further comprises an actuator <NUM>' operably connected to the first electronic control unit <NUM>'. The actuator <NUM>' allows a user to activate and deactivate the second motor/fan unit <NUM>'. The actuator <NUM>' may comprise a button, a lever, a switch, or the like. Thus, according to the illustrated embodiments, a user may operate the second vacuum cleaner unit <NUM> as a vacuum cleaner in isolation of the first vacuum cleaner unit <NUM> and may activate the second vacuum cleaner unit <NUM> using the actuator <NUM>'. The second vacuum cleaner unit <NUM> can thus be utilized for sucking up dust via the suction inlet <NUM>' of the second vacuum cleaner unit <NUM>.

According to the embodiments illustrated in <FIG> and <FIG>, the first vacuum cleaner unit <NUM> comprises a battery unit <NUM>. The battery unit <NUM> is configured to power the second motor/fan unit <NUM>, at least when the suction inlet <NUM>' of the second vacuum cleaner unit <NUM> is removed from the airflow path <NUM> of the first vacuum cleaner unit <NUM>, as is illustrated in <FIG>. According to further embodiments of the herein described, the first vacuum cleaner unit <NUM> may comprise a power cord configured to be inserted into a socket so as to power the second motor/fan unit <NUM>.

According to the illustrated embodiments, the control arrangement <NUM> comprises a second electronic control unit <NUM> arranged in the first vacuum cleaner unit <NUM>. According to the illustrated embodiments, the second electronic control unit <NUM> is configured to control the power of the first motor/fan unit <NUM> during operation of the first vacuum cleaner unit <NUM> when the second vacuum cleaner unit <NUM> is removed from the first vacuum cleaner unit <NUM>. The second electronic control unit <NUM> may also be referred to as a first electronic control unit <NUM> since it is arranged in the first vacuum cleaner unit <NUM>. Likewise, the first electronic control unit <NUM>' may also be referred to as a second electronic control unit <NUM>' since it is arranged in the second vacuum cleaner unit <NUM>. However, since the electronic control unit <NUM>' of the second vacuum cleaner unit <NUM> is mentioned first in the claims of the present disclosure, and due to the fact that the apparatus <NUM> only comprises the electronic control unit <NUM>' of the second vacuum cleaner unit <NUM> according to some embodiments of the present disclosure, the electronic control unit <NUM>' of the second vacuum cleaner unit <NUM> is herein referred to as "the first electronic control unit <NUM>‴ and the electronic control unit <NUM> of the first vacuum cleaner unit <NUM> is herein referred to as "the second electronic control unit <NUM>".

The first vacuum cleaner unit <NUM> further comprises an actuator <NUM> operably connected to the second electronic control unit <NUM>. The actuator <NUM> allows a user to activate and deactivate the first motor/fan unit <NUM>. The actuator <NUM> may comprise a button, a lever, a switch, or the like. Thus, according to the illustrated embodiments, a user may operate the first vacuum cleaner unit <NUM> as a vacuum cleaner in isolation of the second vacuum cleaner unit <NUM> and may activate the first vacuum cleaner unit <NUM> using the actuator <NUM>. The first vacuum cleaner unit <NUM> can thus be utilized for sucking up dust via the suction inlet <NUM> of the first vacuum cleaner unit <NUM>.

According to the illustrated embodiments, the connection interface <NUM> comprises electrical connections <NUM>, <NUM>' configured operably connect the first and second electronic control units <NUM>, <NUM>' when the apparatus <NUM> is in the connected state, i.e. when the suction inlet <NUM>' of the second vacuum cleaner unit <NUM> is connected to the airflow path <NUM> of the first vacuum cleaner unit <NUM>, as is illustrated in <FIG>. In the following, simultaneous reference is made to <FIG> and <FIG>.

According to some embodiments, the second electronic control unit <NUM> is configured to control the power of the first and second motor/fan units <NUM>, <NUM>' when the control arrangement <NUM> is operating in the cooperative cleaning mode. According to these embodiments, the second electronic control unit <NUM> may communicate with the first electronic control unit <NUM>' via the electrical connections <NUM> when the apparatus <NUM> is in the connected state as is illustrated in <FIG>. The second electronic control unit <NUM> may further cause the first electronic control unit <NUM>' to activate the second motor/fan unit <NUM>' upon actuation of the actuator <NUM> of the first vacuum cleaner unit <NUM>. As an alternative, the second electronic control unit <NUM> may activate the second motor/fan unit <NUM>' upon actuation of the actuator <NUM> of the first vacuum cleaner unit <NUM> without communicating with the first electronic control unit <NUM>'.

According to further embodiments of the present disclosure, the first electronic control unit <NUM>' is configured to control the power of the first and second motor/fan units <NUM>, <NUM>' when the control arrangement <NUM> is operating in the cooperative cleaning mode. According to these embodiments, the first electronic control unit <NUM>' may communicate with the second electronic control unit <NUM> via the electrical connections <NUM> when the apparatus <NUM> is in the connected state as is illustrated in <FIG>. The first electronic control unit <NUM>' may further cause the second electronic control unit <NUM> to activate the first motor/fan unit <NUM>' upon actuation of the actuator <NUM> of the first vacuum cleaner unit <NUM>.

According to still further embodiments of the present disclosure, the apparatus <NUM> comprises no second electronic control unit <NUM> arranged in the first vacuum cleaner unit <NUM>. According to these embodiments, the first electronic control unit <NUM>' arranged in the second vacuum cleaner unit <NUM> may be configured to control the power of the first motor/fan unit <NUM> when the vacuum cleaner apparatus <NUM> is in the connected state and when the control arrangement <NUM> is operating in the cooperative cleaning mode. Moreover, the first electronic control unit <NUM>' arranged in the second vacuum cleaner unit <NUM> may be configured to control the power of the first motor/fan unit <NUM> when the control arrangement <NUM> is operating in the non-cooperative cleaning mode described herein. Also in these embodiments, the actuator <NUM> of the first vacuum cleaner unit <NUM> may be operably connected to the first electronic control unit <NUM>' via the electrical connections <NUM> allowing the first electronic control unit <NUM>' to control the first and second motor/fan units <NUM>, <NUM>' based on input from the actuator <NUM> of the first vacuum cleaner unit <NUM>.

Moreover, according to the illustrated embodiments, the electrical connections <NUM> are configured to transfer electricity between the first and second vacuum cleaner units <NUM>, <NUM>. In more detail, the battery unit <NUM>' of the second vacuum cleaner unit <NUM> is rechargeable and is configured to be charged using electricity supplied via the electrical connections <NUM>. The battery unit <NUM>' of the second vacuum cleaner unit <NUM> may be charged using electricity from the battery unit <NUM> of the first vacuum cleaner unit <NUM>. As an alternative, or in addition, the battery unit <NUM>' of the second vacuum cleaner unit <NUM> may be charged using electricity supplied via a power cord of the first vacuum cleaner unit <NUM>.

According to the illustrated embodiments, the second motor/fan unit <NUM>' is differently configured than the first motor/fan unit <NUM>. The second motor/fan unit <NUM>' may be differently configured than the first motor/fan unit <NUM> regarding type and/or size of the electric motor <NUM>' and/or regarding type and/or size of the fan <NUM>'. As an alternative, or in addition, the second motor/fan unit <NUM>' may be differently configured than the first motor/fan unit <NUM> regarding working point. The working points of the first and second first motor/fan unit <NUM>, <NUM>' may be defined as the airflow rate generated at the highest ratio between suction power and inputted electrical energy. The suction power may be defined as the flowrate times pressure difference generated.

According to the illustrated embodiments, the second motor/fan unit <NUM>' comprises a brushless motor <NUM>' configured to power the fan <NUM>'. Moreover, the first motor/fan unit <NUM> comprises a brushed motor <NUM>, such as a canister motor, configured to power the fan <NUM>. By combining a brushed motor <NUM> and a brushless motor <NUM>', a still wider operational range of the apparatus can be provided, as is further explained herein.

According to the embodiments illustrated in <FIG> and <FIG>, the apparatus <NUM> comprises a brush roll <NUM> arranged at the suction inlet <NUM> of the first vacuum cleaner unit <NUM>. The apparatus <NUM> may comprise an electric motor configured to rotate the brush roll <NUM>. According to such embodiments, one or both of the first and second electronic control units <NUM>, <NUM>' may control operation of the brush roll <NUM>. According to further embodiments, the apparatus <NUM> may comprise a vacuum motor configured to rotate the brush roll <NUM> for example using the airflow in the airflow path <NUM> of the first vacuum cleaner unit <NUM> to rotate the brush roll <NUM>.

<FIG> illustrates a graph showing the correlation between the airflow rate Af and the energy efficiency E of the apparatus <NUM> according to some embodiments explained with reference to <FIG> and <FIG> when in the connected state. Below, simultaneous reference is made to <FIG>. The x-axis of the graph in <FIG> shows the airflow rate Af in litres per second at the suction inlet <NUM> of the first vacuum cleaner unit <NUM>. The y-axis of the graph in <FIG> shows the energy efficiency E of the apparatus <NUM> in percentage. The energy efficiency E of the apparatus <NUM> is herein defined as the ratio between the useful output in the form of airflow at the suction inlet <NUM> of the first vacuum cleaner unit <NUM> and the input of electrical energy.

The dotted line provided with the reference sign s1 indicates the airflow rate Af and energy efficiency E when the apparatus <NUM> is operating in the non-cooperative mode, i.e. when only the first motor/fan unit <NUM> is operated and the apparatus <NUM> is in the connected state. The dotted line provided with the reference sign s1 corresponds to an airflow rate Af and energy efficiency E of a prior art vacuum cleaner comprising one motor/fan unit only.

As can be seen in <FIG>, the apparatus <NUM> has a relative high energy efficiency in a lower operational range r1 at approximately <NUM> and <NUM> litres per second when operating in the non-cooperative mode. However, the apparatus <NUM> has a relative narrow operational range r1 regarding the possible airflow rate Af.

The full line provided with the reference sign s2 indicates the airflow rate Af and energy efficiency E of an apparatus <NUM> explained with reference to <FIG> and <FIG> operating in the cooperative mode, wherein the apparatus <NUM> comprises a first and second motor/fan unit <NUM>, <NUM>' of identical design.

The dashed line provided with the reference sign s3 indicates the airflow rate Af and energy efficiency E an apparatus <NUM> explained with reference to <FIG> and <FIG> operating in the cooperative mode, wherein the apparatus <NUM> comprises a first and second motor/fan unit <NUM>, <NUM>' having different working points. The different working points of the first and second motor/fan units <NUM>, <NUM>' may be obtained by providing the first and second motor/fan units <NUM>, <NUM>' with different types of motors <NUM>, <NUM>', and or by providing the first and second motor/fan units <NUM>, <NUM>' with different types of fans <NUM>, <NUM>', such as different sizes, different number of blades, different blade angles, and the like.

As can be seen from the full line s2, the apparatus <NUM> comprising a first and second motor/fan unit <NUM>, <NUM>' of identical design has a significantly higher output capacity and a wider operational range r2 regarding airflow rate Af when operating in the cooperative cleaning mode than a prior art vacuum cleaner comprising one motor/fan unit only. Moreover, the apparatus <NUM> has a significantly greater energy efficiency E at higher output levels than prior art vacuum cleaner comprising one motor/fan unit only.

Likewise, as can be seen from the dashed line s3, the apparatus <NUM> comprising a first and second motor/fan unit <NUM>, <NUM>' having different working points has a significantly higher output capacity and a wider operational range r3 regarding airflow rate Af when operating in the cooperative cleaning mode than the apparatus <NUM> comprising a first and second motor/fan unit <NUM>, <NUM>' of identical design (the full line). Moreover, the apparatus <NUM> comprising a first and second motor/fan unit <NUM>, <NUM>' having different working points has a greater energy efficiency E at higher output levels than prior art vacuum cleaner comprising one motor/fan unit only. In addition, the apparatus <NUM> comprising a first and second motor/fan unit <NUM>, <NUM>' having different working points has a significantly greater energy efficiency E at higher output levels, i.e. above approximately <NUM> litres per second in the illustrated example, than the apparatus <NUM> comprising a first and second motor/fan unit <NUM>, <NUM>' of identical design (the full line).

According to embodiments herein, the control arrangement <NUM> may be configured to operate the apparatus <NUM> in the non-cooperative cleaning mode at lower output ranges and may switch to the cooperative cleaning mode when a wanted output reaches a threshold Th. In this manner, the energy efficiency E of the apparatus <NUM> can be maximized. In the illustrated example, the threshold Th is set to approximately <NUM> litres per second. This is because in the illustrated example, the apparatus <NUM> has a greater energy efficiency E at airflow rates below <NUM> litres per second when operating in the non-cooperative cleaning mode whereas the apparatus <NUM> has a greater energy efficiency E at airflow rates above <NUM> litres per second when operating in the cooperative cleaning mode. Thus, by switching between the non-cooperative cleaning mode and the cooperative cleaning mode based on a wanted output level, the energy efficiency E of the apparatus <NUM> can be maximized. As understood from the persons skilled in the art, the threshold Th may be set to another value depending on the design of the apparatus <NUM>.

<FIG> illustrates a method <NUM> of operating a vacuum cleaner apparatus <NUM> according to some embodiments. The vacuum cleaner apparatus <NUM> may be a vacuum cleaner apparatus <NUM> according to the embodiments illustrated in <FIG> and <FIG>, or a vacuum cleaner apparatus <NUM> according to the embodiments illustrated in <FIG> and <FIG>, which are further explained below. Therefore, in the following, simultaneous reference is made to <FIG>, <FIG>, and <FIG>. The vacuum cleaner apparatus <NUM> comprises a first vacuum cleaner unit <NUM> and a second vacuum cleaner unit <NUM>. The apparatus <NUM> comprises a first motor/fan unit <NUM> and a first dust separation unit <NUM> arranged in the first vacuum cleaner unit <NUM>. The first motor/fan unit <NUM> is configured to generate an airflow through an airflow path <NUM> of the first vacuum cleaner unit <NUM> to the first dust separation unit <NUM>. The apparatus <NUM> comprises a second motor/fan unit <NUM>' and a second dust separation unit <NUM>' arranged in the second vacuum cleaner unit <NUM>. The second motor/fan unit <NUM>' is configured to generate an airflow from a suction inlet <NUM>', <NUM>" of the second vacuum cleaner unit <NUM> to the second dust separation unit <NUM>'. The apparatus <NUM> comprises a connection interface <NUM> configured to removably connect the suction inlet <NUM>', <NUM>" of the second vacuum cleaner unit <NUM> to the airflow path <NUM> of the first vacuum cleaner unit <NUM>. As illustrated in <FIG>, the method <NUM> comprises the step of:.

Moreover, as is illustrated in <FIG>, the step <NUM> of operating the motor/fan units <NUM>, <NUM>' of the first and second vacuum cleaner units <NUM>, <NUM> simultaneously may comprise the step of:.

Thereby, the method <NUM> provides conditions for significantly widening the operational range in which the vacuum cleaner apparatus <NUM> can be operated in an efficient manner.

<FIG> schematically illustrates a vacuum cleaner apparatus <NUM> according to some further embodiments. The vacuum cleaner apparatus <NUM> illustrated in <FIG> comprises the same features, functions, and advantages, as the vacuum cleaner apparatus <NUM> explained with reference to <FIG>, with some minor differences explained below.

According to the embodiments illustrated in <FIG>, the second vacuum cleaner unit <NUM> of the vacuum cleaner apparatus <NUM> comprises an auxiliary suction inlet <NUM>" in addition to a main suction inlet <NUM>'. According to these embodiments, the connection interface <NUM> is configured to removably connect the auxiliary suction inlet <NUM>" of the second vacuum cleaner unit <NUM> to the airflow path <NUM> of the first vacuum cleaner unit <NUM>. In <FIG>, the vacuum cleaner apparatus <NUM> is illustrated in a connected state in which the auxiliary suction inlet <NUM>" of the second vacuum cleaner unit <NUM> is connected to the airflow path <NUM> of the first vacuum cleaner unit <NUM>. According to the illustrated embodiments, the connection interface <NUM> is configured to block the main suction inlet <NUM>' when the apparatus <NUM> is in the connected state. According to further embodiments, the apparatus <NUM> may comprise another type of arrangement for blocking the main suction inlet <NUM>' when the apparatus <NUM> is in the connected state.

<FIG> illustrates the vacuum cleaner apparatus <NUM> according to the embodiments illustrated in <FIG> in a in a disconnected state, i.e. in a state in which the auxiliary suction inlet <NUM>" of the second vacuum cleaner unit <NUM> is removed from the airflow path <NUM> of the first vacuum cleaner unit <NUM>. As can be seen in <FIG>, the second vacuum cleaner unit <NUM> can be used to suck up dust via the main suction inlet <NUM>' of the second vacuum cleaner unit <NUM>. Moreover, as indicated in <FIG>, the second vacuum cleaner unit <NUM> comprises a closure member <NUM>'. The closure member <NUM>' of the second vacuum cleaner unit <NUM> may also be referred to as a second closure member <NUM>'. The closure member <NUM>' is movably arranged between an open position, in which the closure member <NUM>' opens the auxiliary suction inlet <NUM>", and a closed position, in which closure member <NUM>' closes the auxiliary suction inlet <NUM>". In <FIG>, the closure member <NUM>' is illustrated in the open position and in <FIG> the closure member <NUM>' is illustrated in the closed position. According to some embodiments, the closure member <NUM>' is configured to assume the closed position when the second vacuum cleaner unit <NUM> is removed from the first vacuum cleaner unit <NUM>. Moreover, the closure member <NUM>' may be configured to assume the open position when the second vacuum cleaner unit <NUM> is connected to the first vacuum cleaner unit <NUM>. As an alternative, or in addition, the closure member <NUM>' may be manually operated allowing a user to manually move the closure member <NUM>' between the open and closed positions.

The following is explained with simultaneous reference to <FIG>. One skilled in the art will appreciate that the method <NUM> of operating a vacuum cleaner apparatus <NUM> may be implemented by programmed instructions. These programmed instructions are typically constituted by a computer program, which, when it is executed in the control arrangement <NUM>, ensures that the control arrangement <NUM> carries out the desired control, such as the method steps <NUM> and <NUM> described herein. The computer program is usually part of a computer program product which comprises a suitable digital storage medium on which the computer program is stored.

One or more of the control arrangement <NUM>, the first electronic control unit <NUM>' and the second electronic control unit <NUM> may comprise a calculation unit which may take the form of substantially any suitable type of processor circuit or microcomputer, e.g. a circuit for digital signal processing (digital signal processor, DSP), a Central Processing Unit (CPU), a processing unit, a processing circuit, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions. The herein utilised expression "calculation unit" may represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above.

One or more of the control arrangement <NUM>, the first electronic control unit <NUM>' and the second electronic control unit <NUM> may further comprise a memory unit, wherein the calculation unit may be connected to the memory unit, which may provide the calculation unit with, for example, stored program code and/or stored data which the calculation unit may need to enable it to do calculations. The calculation unit may also be adapted to store partial or final results of calculations in the memory unit. The memory unit may comprise a physical device utilised to store data or programs, i.e., sequences of instructions, on a temporary or permanent basis. According to some embodiments, the memory unit may comprise integrated circuits comprising silicon-based transistors. The memory unit may comprise e.g. a memory card, a flash memory, a USB memory, a hard disc, or another similar volatile or non-volatile storage unit for storing data such as e.g. ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), etc. in different embodiments.

One or more of the control arrangement <NUM>, the first electronic control unit <NUM>' and the second electronic control unit <NUM> may be connected to components of the vacuum cleaner apparatus <NUM> for receiving and/or sending input and output signals. These input and output signals may comprise waveforms, pulses, or other attributes which the input signal receiving devices can detect as information and which can be converted to signals processable by the control arrangement <NUM>, the first electronic control unit <NUM>' and/or the second electronic control unit <NUM>. These signals may then be supplied to a calculation unit of the vacuum cleaner apparatus <NUM>. Each of the connections to the respective components of the vacuum cleaner apparatus <NUM> for receiving and sending input and output signals may take the form of a cable.

In the embodiments illustrated, the control arrangement <NUM> of the vacuum cleaner apparatus <NUM> comprises two electronic control units <NUM>, <NUM>' but might alternatively be implemented wholly or partly in three or more control units, or in one control unit as is explained herein.

It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the present invention, as defined by the appended claims.

Claim 1:
A vacuum cleaner apparatus (<NUM>) comprising a first vacuum cleaner unit (<NUM>) and a second vacuum cleaner unit (<NUM>), the apparatus (<NUM>) comprising a first motor/fan unit (<NUM>) and a first dust separation unit (<NUM>) arranged in the first vacuum cleaner unit (<NUM>), wherein the first motor/fan unit (<NUM>) is configured to generate an airflow through an airflow path (<NUM>) of the first vacuum cleaner unit (<NUM>) to the first dust separation unit (<NUM>),
and wherein the apparatus (<NUM>) comprises a second motor/fan unit (<NUM>') and a second dust separation unit (<NUM>') arranged in the second vacuum cleaner unit (<NUM>), and wherein the second motor/fan unit (<NUM>') is configured to generate an airflow from a suction inlet (<NUM>', <NUM>") of the second vacuum cleaner unit (<NUM>) to the second dust separation unit (<NUM>'),
characterised in that the apparatus (<NUM>) comprises a connection interface (<NUM>) configured to removably connect the suction inlet (<NUM>', <NUM>") of the second vacuum cleaner unit (<NUM>) to the airflow path (<NUM>) of the first vacuum cleaner unit (<NUM>),
and wherein the apparatus (<NUM>) comprises a control arrangement (<NUM>) capable of operating the apparatus (<NUM>) in a cooperative cleaning mode in which the first and second motor/fan units (<NUM>, <NUM>') are operated simultaneously.