Patent Application
20240335077
This disclosure relates generally to surface cleaning apparatus such as hand vacuum cleaners, upright vacuum cleaners, stick vacuum cleaners, canister vacuum cleaners, wet dry vacuum cleaner or extractors and, in particular, portable surface cleaning apparatus, such as hand vacuum cleaners.
The following is not an admission that anything discussed below is part of the prior art or part of the common general knowledge of a person skilled in the art.
Various types of surface cleaning apparatus are known, including upright surface cleaning apparatus, canister surface cleaning apparatus, stick surface cleaning apparatus, hand carriable surface cleaning apparatus such as hand vacuum cleaners, wet dry surface cleaning apparatus and extractors. Further, various designs for cyclonic surface cleaning apparatus, including battery operated cyclonic hand vacuum cleaners are known in the art.
The following introduction is provided to introduce the reader to the more detailed discussion to follow. The introduction is not intended to limit or define any claimed or as yet unclaimed invention. One or more inventions may reside in any combination or sub-combination of the elements or process steps disclosed in any part of this document including its claims and figures.
In accordance with an aspect of this disclosure, which may be used alone or in combination with any one or more other aspects, a method is provided for preventing overheating in a surface cleaning apparatus. The surface cleaning apparatus can include a suction motor usable to generate vacuum suction through the airflow path of the apparatus. The operating temperature of the suction motor can be monitored while the surface cleaning apparatus is operational. When the operating temperature reaches a predetermined level, an overheat prevention response can be automatically initiated in response to detecting the predetermined temperature level.
The overheat prevention response can be defined to help mitigate or prevent further overheating of the suction motor. The response can include outputting a visible and/or audible indicator advising that the surface cleaning apparatus should be cleaned or emptied. The response may alternately or in addition include opening a bleed valve to permit additional motor cooling air to enter the airflow path. This can allow the user to continue operating the surface cleaning apparatus for a longer period while also mitigating the risk of suction motor burn out. In some cases, the overheat prevention response can alternately or in addition include deactivating the suction motor. This may be included as part of a subsequent overheat response, e.g. where the initial overheat response was insufficient to prevent further overheating.
In accordance with this aspect, there is provided a method of preventing overheating in a handheld surface cleaning apparatus, the handheld surface cleaning apparatus comprising an air flow path from a dirty air inlet to a clean air outlet, an air treatment member provided in the air flow path, and a motor and fan assembly provided in the air flow path, the method comprising:
The overheat prevention response can include illuminating an overheat indicator light on an external body of the handheld surface cleaning apparatus.
The overheat prevention response can include opening a bleed valve in an external body of the handheld surface cleaning apparatus, where the bleed valve is fluidly coupled to a portion of the airflow path between the air treatment member and the motor and fan assembly.
The handheld surface cleaning apparatus can include a pre-motor filter positioned in the airflow path between the air treatment member and the motor and fan assembly, and the portion of the airflow path can be downstream of the pre-motor filter.
The overheat prevention response can include opening a bleed valve in an external body of the handheld surface cleaning apparatus, where the bleed valve is fluidly coupled to a portion of the airflow path between the air treatment member and the motor and fan assembly.
The overheat prevention response can include deactivating the motor and fan assembly.
The method can include subsequently determining that the operating temperature has reached a further overheat threshold temperature and triggering a subsequent overheat prevention response in response to determining that the operating temperature has reached the further overheat threshold temperature.
The subsequent overheat prevention response can include deactivating the motor and fan assembly.
The operating temperature of the motor and fan assembly can be monitored directly.
The operating temperature of the motor and fan assembly can be monitored by measuring an air temperature of air in the airflow path downstream of the motor and fan assembly.
In accordance with an aspect of this disclosure, which may be used alone or in combination with any one or more other aspects, there is provided a hand surface cleaning apparatus having a front end and a rear end, the hand surface cleaning apparatus comprising:
The hand surface cleaning apparatus can include an apparatus body enclosing the air flow path and an overheat indicator light on an external portion of the apparatus body, where the overheat prevention response includes illuminating the overheat indicator light.
The motor and fan assembly can be provided in the air flow path downstream of the air treatment member.
The hand surface cleaning apparatus can include an apparatus body enclosing the air flow path and a bleed valve through the apparatus body, where the bleed valve is fluidly coupled to a portion of the airflow path between the air treatment member and the motor and fan assembly and where the overheat prevention response includes opening the bleed valve.
The motor and fan assembly can be provided in the air flow path downstream of the air treatment member and a pre-motor filter can be positioned in the airflow path between the air treatment member and the motor and fan assembly, where the portion of the airflow path can be downstream of the pre-motor filter.
The hand surface cleaning apparatus can include an apparatus body enclosing the air flow path and a bleed valve through the apparatus body, where the bleed valve is fluidly coupled to a portion of the airflow path between the air treatment member and the motor and fan assembly and where the overheat prevention response can include opening the bleed valve.
The motor and fan assembly can be provided in the air flow path downstream of the air treatment member.
The overheat prevention response can include deactivating the motor and fan assembly.
The controller can be operable to subsequently determine that the operating temperature has reached a further overheat threshold temperature and trigger a subsequent overheat prevention response in response to determining that the operating temperature has reached the further overheat threshold temperature.
The subsequent overheat prevention response can include deactivating the motor and fan assembly.
The controller can be operable to directly monitor the operating temperature of the motor and fan assembly.
The controller can be operable to monitor the operating temperature of the motor and fan assembly by measuring an air temperature of air in the airflow path downstream of the motor and fan assembly.
It will be appreciated by a person skilled in the art that an apparatus or method disclosed herein may embody any one or more of the features contained herein and that the features may be used in any particular combination or sub-combination.
These and other aspects and features of various embodiments will be described in greater detail below.
For a better understanding of the described embodiments and to show more clearly how they may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:
The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the teaching of the present specification and are not intended to limit the scope of what is taught in any way.
Various apparatuses, methods and compositions are described below to provide an example of an embodiment of each claimed invention. No embodiment described below limits any claimed invention and any claimed invention may cover apparatuses and methods that differ from those described below. The claimed inventions are not limited to apparatuses, methods and compositions having all of the features of any one apparatus, method or composition described below or to features common to multiple or all of the apparatuses, methods or compositions described below. It is possible that an apparatus, method or composition described below is not an embodiment of any claimed invention. Any invention disclosed in an apparatus, method or composition described below that is not claimed in this document may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicant(s), inventor(s) and/or owner(s) do not intend to abandon, disclaim, or dedicate to the public any such invention by its disclosure in this document.
The terms “an embodiment,” “embodiment,” “embodiments,” “the embodiment,” “the embodiments,” “one or more embodiments,” “some embodiments,” and “one embodiment” mean “one or more (but not all) embodiments of the present invention(s),” unless expressly specified otherwise.
The terms “including,” “comprising” and variations thereof mean “including but not limited to,” unless expressly specified otherwise. A listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms “a,” “an” and “the” mean “one or more,” unless expressly specified otherwise.
As used herein and in the claims, two or more parts are said to be “coupled”, “connected”, “attached”, or “fastened” where the parts are joined or operate together either directly or indirectly (i.e., through one or more intermediate parts), so long as a link occurs. As used herein and in the claims, two or more parts are said to be “directly coupled”, “directly connected”, “directly attached”, or “directly fastened” where the parts are connected in physical contact with each other. None of the terms “coupled”, “connected”, “attached”, and “fastened” distinguish the manner in which two or more parts are joined together.
Furthermore, it will be appreciated that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the example embodiments described herein. However, it will be understood by those of ordinary skill in the art that the example embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the example embodiments described herein. Also, the description is not to be considered as limiting the scope of the example embodiments described herein.
Referring to
The surface cleaning apparatus 100 includes a main body 120. The main body 120 includes a main body housing 122 and a handle 124. As exemplified, the handle 124 may be a pistol grip handle with a hand grip portion 126 that extends generally vertically. It will be appreciated that the main body housing 122 and/or handle 124 may be in other configurations, shapes, and/or positions in other embodiments.
The illustrated example surface cleaning apparatus is a hand vacuum cleaner, which may also be referred to as a “handvac” or “hand-held vacuum cleaner”. As used herein, a hand vacuum cleaner is a vacuum cleaner that can be operated to clean a surface generally one-handedly. That is, the entire weight of the vacuum may be held by the same one hand used to direct a dirty air inlet of the vacuum cleaner with respect to a surface to be cleaned. For example, the handle and a clean air inlet may be rigidly coupled to each other (directly or indirectly) so as to move as one while maintaining a constant orientation relative to each other. This is to be contrasted with canister and upright vacuum cleaners, whose weight is typically supported by a surface (e.g., a floor) during use.
It will be appreciated that any one or more of the features of the surface cleaning apparatus 100 set out herein may alternately be used in any type of surface cleaning apparatus, such as an upright surface cleaning apparatus, a stick vac, a canister surface cleaning apparatus, an extractor or the like. It will also be appreciated that a surface cleaning apparatus may use any configuration of the operating components and the airflow paths exemplified herein.
It will also be appreciated that the surface cleaning apparatus 100 may form a part of a larger surface cleaning apparatus (e.g., a stick vacuum cleaner). For example, the surface cleaning apparatus 100 may be mounted to an outlet end of an upright support member or rigid wand or external conduit (e.g., a wand of a stick vacuum).
As exemplified in
As exemplified in
As exemplified in
The exemplary air treatment member 202 includes an air treatment chamber 210. The air treatment chamber 210 has a chamber housing 212. The air treatment chamber 210 may be a cyclone chamber, as exemplified.
As exemplified, the air treatment chamber 210 may include a chamber first end wall 222 (e.g., front end wall) at the chamber first end 214 and a chamber second end wall 224 (e.g., rear end wall) at the chamber second end 216. The air treatment chamber 210 includes a chamber sidewall 220 extending between the chamber first end 214 and the chamber second end 216. The air treatment chamber sidewall 220 may be a generally cylindrical sidewall. A generally cylindrical sidewall encourages cyclonic air flow within the chamber. The air treatment chamber sidewall 220 may have a generally constant diameter. However, it will be appreciated that any suitable shape may be used for the air treatment chamber.
The air treatment inlet 230 includes a chamber inlet opening 234, and the air treatment outlet 232 includes a chamber outlet opening 236, with the air flow path extending through the chamber inlet opening 234 and the chamber outlet opening 236. However, it will be appreciated that the air treatment inlet 230 and/or the air treatment outlet 232 may include more than just an opening.
As exemplified, the air treatment outlet 232 may include a screen that may be a vortex finder 238 extending into the air treatment chamber, and the air treatment inlet 230 may include a projecting conduit 240 extending into the air treatment chamber 210.
The air treatment assembly 200 includes a dirt collection region 300. Optionally, the dirt collection region 300 may be external to the air treatment chamber 210. The dirt collection region may be located in a separate dirt collection chamber from the air treatment chamber 210. The separate dirt collection chamber may communicate with the air treatment chamber 210 via a dirt outlet (e.g., an opening in a wall of the air treatment chamber or a gap between walls of the air treatment chamber). Alternatively, as exemplified, the dirt collection region may be an area of the air treatment chamber 210 (i.e., is internal to the air treatment chamber 210). It will be appreciated that the air treatment assembly 200 may include any suitable number of discrete dirt collection regions.
It will also be appreciated that, while a single air treatment chamber is exemplified, the air treatment assembly may comprise two or more treatment stages. For example, the air treatment assembly may comprise two or more cyclonic cleaning stages, each of which may comprise one cyclone or a plurality of cyclones in parallel.
As exemplified in
The suction motor 322 is contained within a suction motor housing 324. The suction motor housing 324 may form part of the outer surface of the main body housing 122, or may be internal thereto. The suction motor housing 324 may be of any suitable construction, including those exemplified herein.
The suction motor 322 in the illustrated example is positioned downstream from the air treatment member 202, although it will be appreciated that the suction motor 322 may alternatively be positioned upstream of the air treatment member 202 (e.g., a dirty air motor).
As exemplified, the motor 322 may be rearward of the cyclone air treatment assembly 200. The suction motor 322 may be located at the apparatus rear end 104, and may be located at the apparatus upper end 106, as exemplified. Air may travel rearwardly from the air treatment assembly 200 to the suction motor 322, and air flow direction between the air treatment member 202 and the suction motor 322 may have a rearward component at each point along the way. It will be appreciated that the surface cleaning apparatus 100 may have a different configuration and the motor 322 may be located elsewhere with respect to the other components of the air flow path and the handle.
The surface cleaning apparatus 100 may include one or more filters, such as one or more pre-motor filters 330 in the air flow path 160 upstream of the suction motor 322 (e.g., upstream of the motor 322 and downstream of the air treatment assembly 200) and/or one or more post-motor filters 332 in the air flow path 160 downstream of the suction motor 322. The pre-motor filter 330 and the post-motor filter 332 may be formed from any suitable physical, porous filter media and may have any suitable shape, including the examples disclosed herein. For example, the pre-motor filter 330 and/or the post-motor filter 332 may be one or more of a foam filter, felt filter, HEPA filter, other physical filter media, electrostatic filter, and the like. Optionally, one or both of the pre-motor filter 330 and the post-motor filter 332 includes a series of screens or porous filter media (e.g., foam and/or felt), and, optionally, each downstream screen or porous filter media of the filter has finer openings or pores than the preceding upstream screen or porous filter media.
The pre-motor filter 330 may be provided in a pre-motor filter housing 334. The pre-motor filter housing 334 may form part of the outer surface of the main body housing 122. The pre-motor filter housing 334 may be of any suitable construction, including any of those exemplified herein. The pre-motor filter housing 334 may be openable or accessible to allow the pre-motor filter 330 to be cleaned and/or replaced. The pre-motor filter 330 may come in any suitable shape or location. The pre-motor filter may be a donut filter, with a cylindrical body of filtration material surrounding a central cavity, as illustrated. The donut filter may be arranged with the central cavity extending generally horizontally, with an upstream end closed by a filter end cap 338 and the downstream end open (e.g., into the suction motor housing 324, as exemplified). The donut filter may be cylindrical or frusto-conical in shape.
The post-motor filter 332 may be provided in a post-motor filter housing 340. The post-motor filter housing 340 may form part of the outer surface of the main body housing 122. The post-motor filter housing 340 may be of any suitable construction, including any of those exemplified herein.
The surface cleaning apparatus 100 can include a control system operable to monitor and, optionally, control the operation of the surface cleaning apparatus 100. The control system may include one or more onboard processors communicatively coupled to one or more on board data storage systems storing instructions. The instructions include routines or schedules for operating the surface cleaning apparatus 100, and may include routines or schedules for operating the surface cleaning apparatus 100 in response to input. The input may be user input (e.g., via the user interface 360 which may be a touch panel), such as turning the apparatus on or off or selecting an operational mode. The input may be from one or more components of the surface cleaning apparatus 100, such as from an on-board sensor monitoring an operating temperature of the suction motor 322 and/or an air stream which has been heated by the motor 322, such as an air stream passing over the motor 322 and/or at a location downstream of the motor 322.
The surface cleaning apparatus 100 can also include one or more sensors operable to measure operating conditions of the surface cleaning apparatus. It will be appreciated that any suitable sensor may be included, including any of the sensors described herein. The control system (e.g., the one or more processors) may be communicatively coupled to one or more sensors and/or actuators to receive input and/or provide operation commands thereto.
As exemplified, power may be supplied to the surface cleaning apparatus 100 (e.g., to components or elements such as the suction motor 322) from an on-board energy storage member 350 (e.g., one or more capacitors or batteries). For example, the on-board energy storage member 350 may be a battery or a plurality of batteries. It will be appreciated that in some examples, the surface cleaning apparatus 100 may alternatively or additionally include a power cord to supply power from household mains to the components of the surface cleaning apparatus 100 (e.g., the motor 322) directly, and/or to supply power to the on-board energy storage member 350 (e.g., a capacitor or battery) which in turn supplies power to powered components (e.g., the suction motor 322).
It is possible that in some instances, the airflow path 160 through the surface cleaning apparatus 100 may become fully or partially clogged. For example, the vortex finder 238 and/or pre-motor filter 176 may become partially or fully clogged with particulate matter. For example, over time, the upstream surface of the pre-motor filter 176 or the screen 238 can become clogged upon collecting a threshold amount of dirt from the airflow passing through the surface cleaning apparatus 100. When the upstream surface is clogged, the collected dirt may create substantial impedance to airflow entering the vortex finder 238 and/or pre-motor filter 176. As another example, a large object, such as a ball of hair or popcorn, may become lodged anywhere in the airflow path 160. As a result, backpressure through the airflow path 160 can increase. This can increase the load on the suction motor 322 and may cause the suction motor 322 to increase in temperature. In addition, airflow to the suction motor 322 may be reduced, reducing or preventing the suction motor 322 from being cooled by airflow through the airflow path 160. If this occurs, the suction motor 322 may overheat and may burn out.
The control system can be configured to perform various operations to mitigate or prevent overheating and possible burn out of the suction motor 322. For example, the control system can be configured to perform a process of preventing overheating in the surface cleaning apparatus 200.
At 610, the control system can monitor an operating temperature of the motor and fan assembly 322. The operating temperature can be monitored in order to detect when the temperature of the motor and fan assembly 322 is approaching or reaches a temperature that may damage the motor 322. The operating temperature can be monitored on an ongoing basis while the surface cleaning apparatus is operational and, optionally, after the motor 322 has been deenergized.
The surface cleaning apparatus 100 can include one or more temperature sensors operable to measure an operating temperature of the suction motor 322. Optionally, a temperature sensor can be positioned to monitor the operating temperature of the suction motor 322 directly (e.g., a sensor such as a thermocouple placed on a portion of the motor 322). A temperature sensor can be positioned to measure the temperature of the suction motor 322 while the surface cleaning apparatus 100 is operational. This can ensure that the measured temperature accurately reflects the operating temperature of the suction motor 322.
Alternatively or in addition, a temperature sensor can be arranged to measure an air temperature of air in the airflow path 160 downstream of the suction motor 322. The air temperature downstream of the suction motor 322 can indicate the current temperature of the suction motor 322. This can provide greater flexibility in positioning the temperature sensor within the surface cleaning apparatus 100.
At 620, the control system can determine that the operating temperature (from 610) has reached an overheat threshold temperature. The overheat threshold temperature can indicate that further operation of the surface cleaning apparatus 100 may lead to burn out of the suction motor 322.
The overheat threshold temperature can vary depending on the operational parameters of the suction motor 322. The overheat threshold temperature can be defined as a temperature that is approaching, but has not yet reached, the temperature at which damage to the suction motor 322 would be expected. Optionally, the overheat threshold temperature may be an initial overheat threshold temperature that is defined at an operating temperature at which the suction motor 322 can continue operating (at least for a time, e.g., 2 minutes, 5 minutes or more). Optionally, the temperature may be selected such that, when an overheat prevention response that provides bleed air or additional bleed air is initiated, the cooling provided by the bleed air or additional bleed air prevents the motor 322 from overheating, provided that the air flow that passes through the pre-motor filter is not further reduced. This may allow an initial overheating prevention response to be triggered while enabling the user to continue operating the surface cleaning apparatus 100.
At 630, the control system can trigger an overheat prevention response in response to determining at 620 that the operating temperature has reached an overheat threshold temperature. The overheat preventing response can be defined to mitigate and/or prevent overheating of the suction motor 322 and/or prompt a user to take action to mitigate and/or prevent overheating.
Optionally, the overheat prevention response can include one or more user prompts. The user prompts can be defined to prompt a user to take some action in order to prevent overheating the suction motor 322.
For example, the overheat prevention response can include outputting a overheat indicator. The overheat indicator can include a visible and/or audible output emitted by the surface cleaning apparatus 100. For example, the overheat indicator can include illuminating an overheat indicator light on an external body of the handheld surface cleaning apparatus. The overheat indicator light may be identified as an overheat warning light.
Alternatively or in addition, the overheat indicator may be associated with specific actions to be performed by the user, such as “clean filter/screen” and/or “empty dirt collection region”. The actions may be indicated through text or audio outputs from the surface cleaning apparatus 100.
As exemplified in
The user interface 360 may be communicatively coupled to the control system of the surface cleaning apparatus 100. The user interface 360 can provide information about the operating condition of the suction motor. The user interface may include an information display 364, such as a touchscreen, a display screen, or an illuminable icon. Optionally, the information display 364 can display an overheat indicator triggered by the control system as part of the overheat prevention response. For example, it may display “clean filter/screen”, “empty dirt collection region”, or indicate an amount of run time until the motor 322 will overheat and be shut off.
Alternatively or in addition, the user interface may include an audio output such as a speaker for example. Optionally, the audio output can emit an audible overheat indication triggered by the control system as part of the overheat prevention response.
It will be appreciated that the user interface 360 may be provided at any suitable location on the surface cleaning apparatus 100, and may be any suitable user interface. Optionally, the user interface 360 is provided on the handle and/or an upper surface and/or a rear surface of the surface cleaning apparatus 100 for ease of access or visibility.
Alternately or in addition, the overheat prevention response can include an active cooling response. An active cooling response generally refers to an automatic change to the operating condition of the surface cleaning apparatus that is triggered by the control system and intended to assist in cooling (or preventing/minimizing further heating) of the suction motor 322. For example, the active cooling response can include opening or further opening a bleed valve in an external body of the handheld surface cleaning apparatus.
The bleed valve can be provided to deliver exterior air to the air flow path 160 through the vacuum cleaner. The exterior air can provide additional motor cooling air to the suction motor 322. This can allow a user to continue operating the surface cleaning apparatus 100 in the same manner while helping to prevent further heating of the suction motor 322.
In general, the bleed valve includes a bleed valve air inlet and a bleed valve air outlet and includes a valve member. An airflow passageway extends between a location exterior to the airflow path 160 (e.g., the ambient exterior to apparatus 100) and the interior of the airflow path 160 and includes the bleed valve. This air flow path may consist of the bleed valve or comprise the bleed valve and an additional conduit upstream and/or downstream from the bleed valve.
The bleed valve can be fluidly coupled to a portion of the airflow path 160 upstream of the suction motor 322 so as to introduce bleed air when the bleed air valve is opened. The portion of the airflow path 160 to which the bleed valve is coupled may be any part of the airflow passageway between the dirty air inlet 162 and the clean air outlet 164 upstream of the suction motor 322.
The bleed air may be introduced at various locations. Optionally, the bleed valve can be fluidly coupled to a portion of the airflow path 160 between the air treatment member 202 and the motor and fan assembly 322. This can ensure that cooling air can be provided to the suction motor 322 despite a clog being present in the air treatment member 202 (e.g. in the screen of vortex finder 238) or upstream thereof.
If a pre-motor filter is provided, then bleed valve is optionally fluidly coupled to a portion of the airflow path 160 downstream of the pre-motor filter and upstream of the suction motor. For example, the bleed valve may be provided in the suction motor housing 324 or optionally the pre-motor filter housing 334 provided that the bleed air is introduced downstream of the pre-motor filter. This can ensure that cooling air can still be provided to the suction motor 322 even in cases where the pre-motor filter is clogged.
Alternatively, the bleed valve may be coupled to a portion of the airflow path that is upstream of the pre-motor filter. For example, this may allow the bleed valve to be provided in the pre-motor filter housing 334.
The bleed valve may be opened and closed in any suitable manner. For example, the bleed valve can include an actuator coupled to the control system. The control system can be configured to operate the actuator to open the bleed valve as part of an overheat prevention response.
The actuator may be a power actuator such as e.g., a solenoid or another electromechanical actuator such as a linear actuator or a motor. Optionally a powered actuator may be independent from the control system, such as a powered actuator that is controlled by a simple circuit. A simple circuit may not include a processor or a data storage device, such as a circuit with a toggle (e.g., a switch, slider, or button) that closes the circuit when activated (e.g. in response to an overheat temperature signal) and breaks the circuit when deactivated.
Alternatively, the actuator may be an unpowered actuator such as an aneroid capsule or piston or a bimetallic strip. It will be appreciated that an actuator as described herein may be powered or unpowered, unless otherwise specified. An actuator may include a mechanical coupling to a moveable member which the actuator is provided to move. An actuator may be a linear actuator. An actuator may be a dedicated actuator provided to move only one movable member, or may be a common actuator operable to move more than one movable member (e.g., at the same time, or separately as directed by the control system). If the actuator is a bimetallic strip, then the bimetallic strip changing configuration upon being heated may itself open the bleed air flow path.
Alternatively or in addition, the active cooling response can include deactivating the motor and fan assembly. This can prevent further overheating of the suction motor 322 by preventing further use of the surface cleaning apparatus when the operating temperature has reached the overheat threshold temperature. In such a case, a signal may also be provided to the user, such as by illuminating an overheat light or text on a display screen.
Optionally, at 640 the controller may subsequently determine that the operating temperature has reached a further overheat threshold temperature. For example, the overheat threshold temperature at which the overheat prevention response 630 is initiated can be defined to allow a user to continue operating the surface cleaning apparatus 100 after the overheat threshold temperature has been reached, at least for a short period thereafter, (e.g., the overheat threshold temperature may be a temperature that approaches but is below a temperature at which the motor may be damaged). This may allow a user to finish a cleaning task before stopping to maintain the surface cleaning apparatus 100 (e.g. emptying the dirt collection region, cleaning the screen etc.) to prevent further heating. In such cases, the operating temperature of the suction motor 322 can continue to be monitored while the surface cleaning apparatus 100 is operational.
The further overheat threshold temperature can again depend on the operating parameters of the suction motor 322. The further overheat threshold temperature may be defined as a temperature at which damage to the suction motor 322 (e.g. burnout) would be expected with continued use. Accordingly, the further overheat threshold temperature may be higher than the initial overheat threshold temperature.
Alternatively, the overheat threshold temperature may be the same or similar to the initial threshold temperature sensor but detected for an extended period of time. That is, the further overheat threshold temperature may be the same as the initial overheat threshold temperature but the continued detection of the overheat threshold temperature may indicate that the initial overheat prevention response has been unsuccessful in cooling the suction motor 322. As a result, continued operation of the surface cleaning apparatus 100 may increase the risk of damage or burn-out.
Optionally, at 650 a subsequent overheat prevention response can be triggered in response to determining that the operating temperature has reached the further overheat threshold temperature. This may allow a user to continue operating the surface cleaning apparatus 100 after the initial overheat temperature is detected while still preventing damage to the suction motor.
The subsequent overheat prevention response can be defined as an escalating response from the initial overheat prevention response at 630. For example, the subsequent overheat prevention response can include deactivating the motor and fan assembly. Optionally, the suction motor 322 may be prevented from being reactivated until the measured temperature decreases below the further overheat threshold temperature (or even below a different, lower threshold temperature such as the initial overheat threshold temperature or another reset threshold temperature).
Alternatively or in addition, the subsequent overheat prevention response can include an escalation of the user prompt output (e.g. an increase in volume, brightness, or frequency of an output indicator) or optionally opening a second bleed valve or further opening a single bleed valve that has already been partially opened. The escalated user prompt output can be defined to annoy or disturb the user in order to prompt them into taking corrective actions.
As used herein, the wording “and/or” is intended to represent an inclusive—or. That is, “X and/or Y” is intended to mean X or Y or both, for example. As a further example, “X, Y, and/or Z” is intended to mean X or Y or Z or any combination thereof.
While the above description describes features of example embodiments, it will be appreciated that some features and/or functions of the described embodiments are susceptible to modification without departing from the spirit and principles of operation of the described embodiments. For example, the various characteristics which are described by means of the represented embodiments or examples may be selectively combined with each other. Accordingly, what has been described above is intended to be illustrative of the claimed concept and non-limiting. It will be understood by persons skilled in the art that other variants and modifications may be made without departing from the scope of the invention as defined in the claims appended hereto. The scope of the claims should not be limited by the preferred embodiments and examples, but should be given the broadest interpretation consistent with the description as a whole.
