US20240285139A1

US20240285139A1 - Bagless vacuum cleaner

Info

Publication number: US20240285139A1
Application number: US18/569,801
Authority: US
Inventors: Nicholas Gerald Grey
Original assignee: Grey Technology Ltd
Current assignee: Grey Technology Ltd
Priority date: 2021-06-18
Filing date: 2022-06-17
Publication date: 2024-08-29
Also published as: GB202108714D0; JP2024521300A; CN117545410A; EP4355186A1; WO2022264108A1

Abstract

This invention relates to a bagless vacuum cleaner, and most preferably a battery-powered vacuum cleaner. The vacuum cleaner may be a cylinder vacuum cleaner, an upright vacuum cleaner or a hand-held vacuum cleaner. The bagless vacuum cleaner has a dirt-collection chamber with an inlet and an outlet and a filter at its outlet. According to the invention the vacuum cleaner has an agitator to agitate the filter and dislodge dirt and dust which has adhered to the filter, whereby to extend the period before the filter becomes blocked.

Description

FIELD OF THE INVENTION

This invention relates to a bagless vacuum cleaner.
Unless otherwise stated directional and orientational terms such as “top”, “vertical” etc. refer to the vacuum cleaner in its normal orientation of use with the suction head on a horizontal surface, as shown for example in FIG. 1 . The suction head can, however, be used in other orientations if desired.

BACKGROUND TO THE INVENTION

The owners or occupiers of many domestic and commercial premises utilise a vacuum cleaner to clean the floors and other areas of the premises. A vacuum cleaner operates by generating an air flow through a suction head which is placed upon or against the area to be cleaned. Dirt and debris become entrained in the air flow and are thereby carried into a dirt-collection chamber for subsequent disposal.
Most domestic vacuum cleaners fall into three broad classes. The first class is often referred to as cylinder vacuum cleaners. In cylinder vacuum cleaners the suction head is connected by way of a rigid tube to an operating handle by which the suction head is maneuvered during use. The operating handle is in turn connected to a flexible hose through which the dirt and debris pass on their way to the dirt-collection chamber. The dirt-collection chamber is located within a body which also contains a motor and an impeller to create the air flow, the body having wheels or slides by which it may be moved across the floor (e.g. pulled by way of the hose) during the cleaning operation.
For the avoidance of doubt, the term “impeller” as used in this specification embraces all devices for creating air flow within the vacuum cleaner. The term therefore also includes fans and turbines for example.
The second class is often referred to as upright vacuum cleaners. In upright vacuum cleaners the motor and the impeller are typically mounted in the suction head and the dirt-collection chamber is carried by, or in some cases is integral with, the operating handle, so that the body containing the dirt-collection chamber is typically above the suction head during the cleaning operation. There is usually a pivoting joint or a steering joint between the body and the suction head.
It is not possible to manoeuvre the suction head of an upright vacuum cleaner in the same way as that of a cylinder vacuum cleaner, and in order to enable the cleaning of areas such as stairs the manufacturers of upright vacuum cleaners provide an alternative solution. Specifically, the upright vacuum cleaner is typically fitted with a length of extendable flexible hose between the suction head and the dirt-collection chamber, the end of the hose adjacent to the suction head being releasable whereby the end of the released hose can be fitted with a cleaning tool and maneuvered to the desired location without the user having to move the remainder of the vacuum cleaner. The flexible hose is typically made extendable so that during normal use of the vacuum cleaner the contracted hose can be stored easily and conveniently upon the body of the vacuum cleaner. When released from its stored position the hose can be extended to reach the desired location.
Many cylinder vacuum cleaners, and many upright vacuum cleaners, are mains-powered. The suction head of a cylinder vacuum cleaner, and the released end of the extendable flexible hose of an upright vacuum cleaner, are maneuverable relative to the body of the vacuum cleaner within the limit set by the length of the extended hose. Also, the body of the vacuum cleaner is only maneuverable within the limit set by the length of the mains electrical cable (and the availability of mains electricity sockets). It may therefore not be possible to move the suction head or cleaning tool to all of the locations in which cleaning is desired.
A third class of vacuum cleaner is a hand-held vacuum cleaner. Hand-held vacuum cleaners are typically battery-operated and have a carrying handle which permits the whole vacuum cleaner to be carried during use (typically by one hand), the user being able to manoeuvre the nozzle of the vacuum cleaner to the location of use.
Hand-held vacuum cleaners were originally designed to supplement mains-powered vacuum cleaners and were suited for use in cleaning areas which were difficult to reach with the suction head or cleaning tool of a mains-powered vacuum cleaner, and for small-area or spot cleaning such as clearing up the spillage of a granular product.
Advances in battery technology and improvements in the design of hand-held vacuum cleaners have resulted in reductions in weight and an increase in the periods of use between recharging of the batteries, both of which make hand-held vacuum cleaners more suited to extended periods of use and therefore for the cleaning of larger areas. The utility of hand-held vacuum cleaners has therefore increased and some hand-held vacuum cleaners can nowadays be used as an alternative to a mains-powered vacuum cleaner to clean floors and the like. In particular, a hand-held vacuum cleaner can be adapted to clean floors by including a rigid tube between the suction head and the body of the vacuum cleaner, in a configuration often referred to as a “stick-vac”.
The suction head of all three classes of vacuum cleaner can be fitted with a rotating brush which is designed to engage and physically move dirt and debris into the suction head where it can be entrained in the air flow. Also, the suction head can incorporate a steering joint allowing it to be steered in a chosen direction during use.
WO2012/085567 discloses a modified upright vacuum cleaner which is battery powered. The vacuum cleaner is similar to other upright vacuum cleaners in having an operating handle connected to the suction head by a steering joint. However, in this vacuum cleaner the dirt-collection chamber is located in the suction head together with the motor and the impeller. The batteries are also located in the suction head.
Vacuum cleaners are also distinguished by their treatment of the collected dirt and debris. “Bagged” vacuum cleaners have a disposable bag located in the dirt-collection chamber, the impeller drawing air through the bag during use. The wall of the bag is of paper or fabric and is air-permeable to provide a first-stage filter allowing air to pass through whilst retaining most of the dirt and debris within the interior of the bag. When the bag is full it is removed from the dirt-collection chamber and disposed along with the contained dirt and debris.
“Bagless” vacuum cleaners on the other hand separate the dirt and debris from the air flow within the dirt collection chamber, perhaps by way of a cyclonic separator, by way of a physical filter, or a combination of both. The air passes out of the dirt-collection chamber and most of the dirt and debris is retained in the chamber. The dirt-collection chamber is typically removably mounted to the body and when full it can be removed and taken to a site of disposal, for example a waste bin, where it is opened to allow the contained dirt and debris to be emptied. The empty dirt-collection chamber is reinstalled into the body for re-use.
The vacuum cleaner of WO2012/085567 is bagless. The present invention describes an improvement upon the vacuum cleaner of WO2012/085567 and is suited to vacuum cleaners having a physical filter at the exit of the dirt-collection chamber. The invention can nevertheless be utilised on other bagless vacuum cleaners, whether or not they are battery powered, and whichever of the broad classes described above they fall into. For example, the invention can be used on bagless vacuum cleaners which have one or more cyclonic separators and also have a physical filter at the outlet of the dirt-collection chamber.
The vacuum cleaner of WO2012/085567 has an air flow duct between the rotating brush and the dirt-collection chamber which has a relatively large cross-sectional area. The air flow duct is also relatively short and free of constrictions and discontinuities. This results in a relatively slow-moving and relatively smooth air flow along the duct and into the dirt-collection chamber. In addition, the shaping of the dirt-collection chamber, and the location of the filter above the dirt-collection chamber, encourage the deposition of much of the dirt and debris at desired locations within the dirt-collection chamber, thereby helping to ensure the effective filling of the dirt-collection chamber and reducing the frequency of emptying. In particular, lighter components such as hair and fluff are trapped in the dirt-collection chamber and in turn act to trap much of the fine dirt and dust which also enters the dirt-collection chamber.
Inevitably, however, some of the fine dirt and dust passes through the dirt-collection chamber and into the filter, some of which adheres to the surface of the filter and some of which enters into the pores and passageways of the filter. Over time the filter becomes less porous as fewer of the pores and passageways through which the air can pass remain open; the air flow through the filter reduces and the performance of the vacuum cleaner reduces.
The vacuum cleaner performance will also diminish as the dirt-collection chamber fills with collected dirt and debris. Depending upon the dirt and debris which is collected the air will have to pass through a mass of previously-collected dirt and debris inside the dirt-collection chamber, and/or the clear air-flow path through the dirt-collection chamber will become constricted as the volume of dirt and debris in the dirt-collection chamber increases.
In response to a reduction in vacuum cleaner performance the user will typically empty the dirt-collection chamber. The user may be prompted to empty the dirt-collection chamber by way of a sensor indicating a full dirt-collection chamber. A common form of sensor is an air flow sensor which detects the air flow through a part of the vacuum cleaner, typically the air flow duct between the rotating brush and the dirt-collection chamber. Notwithstanding the provision of a sensor, however, the user will not always appreciate whether the reduction in performance is due to the dirt-collection chamber actually becoming full, to the filter becoming blocked, or to a combination of these causes.
It is routinely possible for a user to remove and clean the filter of a vacuum cleaner, and some filters are washable. Less diligent users will, however, typically avoid cleaning the filter and instead empty the dirt-collection chamber even if only partially filled in an attempt to maintain an effective vacuum cleaner performance.
A reduction in performance as the filter becomes blocked is typically more significant for battery-powered vacuum cleaners than for mains-powered vacuum cleaners. A mains powered vacuum cleaner will typically have a larger motor and a faster-spinning impeller which create a greater air flow than is typically possible with a battery powered vacuum cleaner. An air flow which is reduced because many of the pores and passageways in a filter are blocked might nevertheless be sufficient for continued operation in a mains powered vacuum cleaner whereas a correspondingly reduced air flow might be insufficient for effective and efficient operation of a battery powered vacuum cleaner.

SUMMARY OF THE INVENTION

One object of the present invention is to avoid or reduce the performance deficit caused by the partial blockage of a filter of a bagless vacuum cleaner. The invention can help to maintain the optimum performance of the vacuum cleaner for a longer period of time and reduce the frequency at which the filter needs to be cleaned. The performance of an air flow sensor in the vacuum cleaner can also be improved by avoiding or reducing the likelihood that the air flow diminishes significantly before the dirt-collection chamber is full.
According to the invention there is provided a bagless vacuum cleaner having a dirt-collection chamber with a filter at its outlet, the vacuum cleaner having an agitator configured and positioned to agitate the filter.
The inventors have found that agitating or rapidly moving the filter dislodges dirt (in particular the fine dirt and dust) which has adhered to the surface of the filter and/or become trapped in pores and passageways of the filter. The dislodged dirt and dust can return to the body of the dirt-collection chamber and be retained with the other collected dirt and debris where it no longer blocks the pores or passageways. The pores and passageways (or at least more of the pores and passageways) therefore remain available for the subsequent passage of air.
The vacuum cleaner preferably has an electric motor driving an impeller to create the air flow through the dirt-collection chamber, and an air duct between the filter and the impeller; the agitator is preferably located in the air duct. Desirably the agitator is at least partly sealed in a chamber connected to the air duct. The agitator can therefore be located to the “clean air” side of the filter where it is less likely to encounter dirt and debris. Locating the agitator in a chamber connected to the air duct further enhances this benefit.
Preferably, when the vacuum cleaner is located on a horizontal surface, the filter is oriented substantially horizontally and is located at the top of the dirt-collection chamber. In use, the air flows upwardly through the filter as it leaves the dirt-collection chamber. Fine dirt and dust which is dislodged by the agitator falls into the body of the dirt-collection chamber below the filter, perhaps into previously-collected dirt and debris held in the dirt-collection chamber. It will be understood that the dislodged fine dirt and dust falls under the influence of gravity and a horizontal orientation of the filter is the most efficient because the dislodged fine dirt and dust moves away from the filter substantially in a direction which is perpendicular to the surface of the filter. Alternative arrangements in which the filter is at an angle to the horizontal, including substantially vertical, are nevertheless not excluded, although they are likely to be less efficient.
The filter is preferably movably mounted in the vacuum cleaner, and is desirably movable in a vertical direction when the vacuum cleaner is located on a horizontal surface.
Desirably, the filter overlies the whole of the dirt-collection chamber. The area of the filter is therefore maximised for the size of the dirt-collection chamber. Increasing the area of the filter increases the area through which air can leave the dirt-collection chamber, which in turn reduces the velocity of the air flow through the dirt-collection chamber and increases the likelihood that entrained dirt and debris will be deposited in the dirt-collection chamber as desired.
Preferably, the agitator is actuated intermittently.
Desirably, the agitator is actuated only when the motor of the vacuum cleaner is switched off, and ideally at the end of a cleaning operation. Preferably, the agitator is actuated each time the motor is switched off, i.e. after every use of the vacuum cleaner. Ideally, the agitator is actuated at the end of a chosen delay after the motor has been switched off, the chosen delay being sufficient to allow the impeller to stop rotating (or at least to slow down significantly). Accordingly, the agitator is preferably not seeking to dislodge dirt and dust from the filter at the same time as air is flowing through the filter (which air flow will somewhat oppose the action of the agitator).
The inventors have found that after the dirt and dust has been dislodged from the filter at least some of it becomes trapped within the collected dirt and debris in the dirt-collection chamber; subsequent air flow (for example upon the next use of the vacuum cleaner) does not re-activate all of the dislodged dirt and dust. Accordingly, only a proportion, and often only a small proportion, of the dislodged dirt and dust re-engages the filter when the air flow is resumed so that there is an overall reduction in the amount of dirt and dust coating the surface of the filter and/or blocking the pores and passageways of the filter.
Less preferably the agitator is actuated when the motor is actuated, i.e. at the start of a cleaning operation. It is recognised that the impeller will take some time to build up the air flow through the dirt-collection chamber and filter to its maximum level, during which time the agitator can dislodge dirt and dust from the filter. In such an arrangement the agitator is preferably switched off before the air flow has reached its maximum level.
Whilst it is not precluded that the agitator could operate with the air flow at its maximum level (and could in theory operate all of the time the motor is actuated), it is expected that the agitator will be more effective at dislodging dirt from the filter when there is little or no (competing) air flow.
A single rapid movement of the filter may dislodge sufficient fine dirt and dust in some vacuum cleaners, whereby the agitator can be configured to deliver a single impact to the filter. However, that is not preferred as it is expected that more of the collected fine dirt and dust will be removed (and/or will be more reliably removed) by repeated rapid movements or shaking of the filter. Thus, in preferred embodiments the agitator causes repeated rapid cyclical movement of the filter.
Desirably, the agitator is actuated for a predetermined and uninterrupted period after the motor has been switched off. Preferably, the predetermined period is more than 3 seconds. Preferably also the predetermined period is less than 5 seconds, and more preferably less than 4 seconds.
The chosen delay after which the agitator is actuated (after the motor has been switched off) is preferably less than 3 seconds, ideally less than 2 seconds and most preferably less than 1 second.
As above stated, the agitator is preferably configured to move (impact) the filter repeatedly. Desirably, the impact frequency is less than 100 Hz. The optimum frequency will depend upon the structure of the agitator and the mounting of the filter and can for example with certain structures preferably be between 75 and 100 Hz, ideally between 85 and 90 Hz, and most preferably around 87 Hz.
Preferably, the agitator includes an impacter which is located adjacent to the dirt-collection chamber. Desirably, the impacter is a rotating eccentric element which impacts the filter during each rotation.
The impacter is preferably a circular disc which is eccentrically mounted to a rotatable drive shaft. Preferably also the impacter is mounted to be freely rotatable. The impacter will typically rotate when the filter is impacted. The benefit of a circular disc as the impacter is that its centre of mass does not change as it rotates.
Desirably a balancing element is also mounted to the drive shaft, the balancing element offsetting or counteracting the eccentric mounting of the impacter. The combination of the impacter and the balancing element can therefore be balanced relative to the drive shaft, and can remain balanced both as the impacter rotates when the filter is impacted and also as the impacter and balancing element rotate together with the drive shaft.
Preferably the impacter is mounted to the balancing element which is in turn mounted to the drive shaft; the impacter can therefore be eccentrically mounted to the drive shaft by way of the balancing element.
The drive shaft is preferably directly connected to an electric motor; according to the preferred features the electric motor does not have to accommodate an eccentrically rotating mass.
The impacter is preferably steel with a mass of between 15 g and 20 g, ideally approx. 17.5 g. The impacter is preferably approx. 25 mm in diameter. The impacter is preferably approx. 5 mm thick.
The filter is preferably mounted in a filter support or frame. Preferably, the agitator moves the filter support and thereby moves the filter by way of the filter support. Desirably, the filter-support is a two-part support, with a first part and a second part which can move relative to one another. In this way the filter can be securely (but removably) mounted to the suction head of the vacuum cleaner by way of the first part (which is a structural part which does not move relative to the remainder of the vacuum cleaner). The second part is mounted to move relatively freely relative to the first part (and therefore relative to the remainder of the vacuum cleaner), at least within a certain range. The filter is preferably mounted to the second part.
The second part of the filter support is ideally mounted to the first part of the filter support by a flexible sealing element such as a gaiter or the like which permits relative movement without permitting air flow between the first and second parts. The flexible sealing element is preferably resilient. The impacter can agitate the second part of the filter support and thereby move the second part and the supported filter. In this way the filter is protected from direct impacts from the impacter which might cause damage to the filter. In addition, the second part of the filter support can be made of a relatively rigid material which will not absorb any (or at least will not absorb a significant proportion) of the impact but instead will move rapidly when impacted and pass on that rapid movement to the filter (and ideally to substantially the whole of the filter).
It will be understood that the agitation of the filter preferably comprises multiple cycles of movement (to and fro), the movement being sufficiently rapid to dislodge fine dirt and dust from the filter. Preferably, the movement in one direction is caused directly by the agitator physically engaging the filter (or the filter support) and driving the filter to move in the one direction. The movement in the opposing direction is preferably caused by the resilience of the sealing element and/or gravity. It will be understood that the filter (or filter support) must return sufficiently rapidly to match the desired agitation frequency and additional resilient biasing means can be provided if the sealing element and gravity together cannot move the filter (or filter support) sufficiently rapidly.
Preferably, the first part of the filter support surrounds the second part of the filter support. The dirt-collection chamber preferably has an opening at its top which is substantially oblong in shape. The first or outer part of the filter support is shaped to removably fit to that opening, with a suitable seal to prevent the passage of air from the “dirty air” side of the filter (i.e. in the dirt-collection chamber) to the clean air side of the filter. The second or inner part of the filter support is preferably located inside the first or outer part, desirably with a flexible and continuous convoluted ring or gaiter between the outer and inner parts (which gaiter also prevents the passage of air from the dirty air side of the filter to the clean air side of the filter). The inner part is preferably also substantially oblong in shape and is configured to support a filter of corresponding size and shape.
Desirably, the second part of the filter support has a lower wall and an upper wall. In use the lower wall lies between the dirt-collection chamber and the filter and the upper wall lies between the filter and the air duct to the impeller. The lower and upper walls are perforated to allow air flow from the dirt-collection chamber to pass to the impeller. Ideally the perforations in the lower wall are relatively large so as to maximise the exposed area of the filter. The perforations in the upper wall can be smaller and more numerous to minimise the likelihood of distortion of the filter caused by the air flow in use.
The impacter can be positioned to engage directly the second or inner part of the filter support. Preferably, however, the impacter can strike an impact tab connected to the second or inner part. The impact tab is preferably mounted to the upper wall whereby the agitator is not exposed to the dirty air side of the filter.
There is preferably one agitator, but less preferably there are two or more agitators. If there are two agitators they are preferably located to each side of the vacuum cleaner (and to each side of the dirt-collection chamber). A single motor can actuate multiple agitators, the motor being connected to respective drive shafts communicating drive to the respective agitator.
Desirably, the or each agitator is located in a closed chamber so that it is isolated from the external environment, and also isolated from the dirty air side of the filter.
Desirably, the vacuum cleaner is battery powered. Whilst the invention is not limited to battery powered vacuum cleaners it is expected to have particular benefit for those vacuum cleaners. As above stated, the reduction in performance as the filter of a vacuum cleaner becomes full is likely to be more significant for a battery powered vacuum cleaner than a mains powered vacuum cleaner, and so the benefits of the present invention in diminishing the reduction in performance is particularly beneficial.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 shows a side section through the suction head of a vacuum cleaner according to a first embodiment of the present invention;

FIG. 2 shows a perspective view of part of a second embodiment of bagless vacuum cleaner;

FIG. 3 shows a sectional view through the suction head of the vacuum cleaner of FIG. 2 ;

FIG. 4 shows a sectional plan view of the vacuum cleaner of FIG. 2 ;

FIG. 5 shows a perspective view of the agitator of the embodiment of FIG. 2 ;

FIG. 6 shows a side view of the agitator of FIG. 5 ;

FIG. 7 shows a first perspective view of the impacter and balancing element of the agitator of FIG. 5 ;

FIG. 8 shows a second perspective view of the impacter and balancing element of the agitator of FIG. 5 ;

FIG. 9 shows the impacter of the agitator of FIG. 5 ;

FIG. 10 shows the balancing element of the agitator of FIG. 5 ;

FIG. 11 shows an underside view of an alternative filter support of a vacuum cleaner according to the invention;

FIG. 12 shows a first sectional view through the filter support of FIG. 11 ;

FIG. 13 shows a second sectional view through the filter support of FIG. 11 ;

FIG. 14 shows a lateral section through the dirt-collection chamber of a third embodiment of vacuum cleaner according to the present invention;

FIG. 15 shows a perspective view of the agitator of the third embodiment of vacuum cleaner;

FIG. 16 shows an end view of the agitator of FIG. 15 ;

FIG. 17 shows the balancing element of the agitator of FIG. 15 ;

FIG. 18 shows a perspective view from above of another alternative filter support;

FIG. 19 shows a sectional view through the filter and filter support of FIG. 18 ; and

FIG. 20 shows an enlarged sectional view of an edge of the filter support of FIG. 18 .

DETAILED DESCRIPTION

The vacuum cleaner 102, part of which is shown in FIG. 1 , is battery powered. In known fashion a battery pack is located in the suction head 104 and is connected to a primary motor. The primary motor drives an impeller to rotate to create an air flow from an opening 106 in the bottom surface at the front end of the suction head 104. A rotatable brush 108 is mounted adjacent to the opening 106 and is driven to rotate (by the primary motor or by a separate motor) clockwise as seen in FIG. 1 . The brush 108 engages dirt and debris underneath the opening 106 and works with the air flow to move that dirt and debris into a dirt-collection chamber located in the suction head 104 (see for example the dirt-collection chamber 226 in FIG. 3 and the dirt-collection chamber 326 in FIG. 14 )). The collected dirt and debris is deposited in the dirt-collection chamber and clean air leaves the suction head through a vent adjacent to the motor. The battery, primary motor, impeller and vent are not shown in the drawings as they are incidental to the invention and can be entirely conventional—a suitable arrangement of these components will be readily apparent to the designers of battery-powered vacuum cleaners.
FIG. 1 shows a sectional side view of a first embodiment of the invention. In this embodiment the agitator is a hammer 110 which is pivotably mounted to the suction head 104 and which can strike a part of the filter support 112. The hammer 110 is biased upwardly as drawn into engagement with the part of the filter support by a spring 114. A drop-off cam 116 engages an end of the hammer 110. As the cam 116 rotates clockwise from the position shown it will move the hammer 110 downwards away from the filter support 112, which movement compresses the spring 114. When the cam 116 reaches the position shown in FIG. 1 the hammer 110 drops off the cam 116 and the spring 114 forces the hammer to move upwards and to impact the filter support 112.
The cam 116 is preferably rotated by a secondary motor (not shown), with suitable reduction gearing (also not shown) between the motor and the cam 116.
Details of the effects caused by impacts to the filter support are provided below in relation to the second and third embodiments.
FIG. 2 shows a perspective view of part of a second embodiment of vacuum cleaner 202 according to the present invention, including a part of the suction head 204 and a part of the operating handle 220. FIG. 3 shows a cross sectional view of the vacuum cleaner 202. FIG. 4 shows an approximately horizontal section through the suction head 204.
FIGS. 2-4 show more detail of the filter support 212 and the filter 224 which are mounted at the top of the dirt-collection chamber 226. The filter 224 can be any suitable material that stops fine particles passing to the clean air side, for example a multi-layer foam, a woven material or a pleated filter, as widely used in vacuum cleaners. In one particular embodiment the filter 224 consists of a layer of 90 ppi foam and a 1 mm thick layer comprising an electrostatic filter medium. The filter 224 is not self-supporting and so is mounted in the filter support 212 which provides the required structural rigidity for the filter and helps to ensure that the filter 224 occupies all of the air path between the dirt-collection chamber 226 (dirty air side) and the impeller (clean air side). In the suction head 202 shown in FIGS. 2 and 3 the dirty air side is below the filter 224 and the clean air side is above the filter.
The dirt-collection chamber 226 can be removed from the suction head 204 in known fashion. The dirt-collection chamber is removed with the filter 224, the filter support 212 and a top cover 230 which covers the filter support 212 during use of the vacuum cleaner 202. The top cover 230 has a handle part 228 by which some or all of the top cover together with the filter support 212 (and filter 224), can be separated from the dirt-collection chamber 226 to permit collected dirt and debris to be emptied. When the top cover and filter support have been removed the top of the dirt-collection chamber 226 is open and the dirt-collection chamber can be inverted to tip the collected dirt and debris into a suitable receptacle.
It will be understood that the dirt-collection chamber of the first embodiment of FIG. 1 (and also the third embodiment described below) could be removed and emptied in a similar way.
As above stated, the invention could alternatively be used in a mains powered vacuum cleaner, i.e. without a battery pack. The invention could also alternatively be used in a suitably-constructed cylinder vacuum cleaner, upright vacuum cleaner and/or hand-held vacuum cleaner incorporating a filter at the outlet of the dirt-collection chamber, as desired.
In the second embodiment shown in FIGS. 2-10 , the agitator 240 has an impacter 242 (see also FIGS. 5-9 ) which as seen in FIGS. 2-4 lies to the side of the dirt-collection chamber 226. As the impacter 242 rotates it engages an impact tab 232 carried by the filter support 212 as explained below. The impacter 242 is actuated by a secondary motor 244.
In this embodiment the impacter 242 is a circular steel disc which is 5 mm thick and 25 mm in diameter. The circular disc 242 weighs 17.5 g. The disc 242 has a hole 246 at its centre, which holes receives a bolt 248. The circular disc 242 is freely-rotatable about the bolt 248, so that when it impacts the impact tab 232 the disc can rotate in order to minimise the sideways force upon the impact tab.
The agitator 240 also has a balancing element 250. The balancing element 250 has a threaded hole 252 to receive the bolt 248 and a second hole 254 to receive the drive shaft of the motor 244. The second hole 254 is circular in this embodiment and is an interference fit onto the drive shaft, but in other embodiments can be non-circular. The balancing element 250 and the impacter 242 rotate with the drive shaft.
It will be understood that the impacter 242 is eccentrically mounted to the drive shaft; as the drive shaft rotates the impacter rotates eccentrically. The degree of eccentricity is determined by the distance d between the holes 252 and 254, and in this embodiment is approx. 5 mm.
The motor 244 is fixed in position in the suction head 204 and the rotational axis of the drive shaft is therefore also fixed relative to the suction head 204. Accordingly, as the disc 242 rotates around the drive shaft its periphery translates by a distance 2d during each rotation. It is arranged that the disc is sufficiently close to the impact tab 232 to strike the impact tab once in each rotation.
Notwithstanding the eccentricity of the impacter 242, because the impacter 242 is a circular disc which is mounted at its centre, the centre of mass of the impacter remains aligned with the hole 252 as the drive shaft rotates. The balancing element 250 is therefore configured with a size and shape to directly compensate for the consistent eccentricity of the impacter 242. Accordingly, as the impacter 242 and balancing element 250 rotate together about the drive shaft, their combined mass remains centred at the rotational axis of the drive shaft. The motor 244 therefore does not need to support a rotating eccentric mass.
The suction head 204 has a single agitator 240 at one side of the dirt-collection chamber 226 and this has been found to provide suitable agitation of the filter 224. Alternative embodiments can have two or more agitators spaced around the filter 224 if desired.
It will be seen in FIG. 2 that the impact tab 232 is mounted to the upper wall of the filter support 212, and in particular is rigidly mounted to the top perforated wall 274 of the filter support 212. The impact tab 232 is of right-angle form and has a part which projects downwardly into a region at the side of the dirt-collection chamber 226 in which the agitator 240 is located. That region is entirely located to the clean air side of the filter 224 and no part of the agitator 240 is exposed to the dirt and debris in the dirt-collection chamber 226.
Locating the whole of the agitator 240 on the clean air side of the filter 224 avoids the requirement to provide any seals or the like to protect the agitator from dirt and debris at the dirty air side of the filter.
The detailed structure of the filter supports 112 and 212 are not shown in FIGS. 1-4 but FIGS. 11-13 show the detailed structure of another embodiment of filter support 12, the relevant features of which are shared with the earlier embodiments (and the later embodiment described below).
The filter support 12 has a first or outer part (or frame) 60 which is substantially rigid and is configured for mounting to the top of a particular dirt-collection chamber. A suitable seal (not seen) is provided which will be located between the outer frame 60 and the top wall of the dirt-collection chamber.
The filter support 12 has a second or inner part (or frame) 62 which can move within a limited range relative to the outer frame 60. A filter 24 is located in the inner frame 62 and substantially fills the inner frame. A flexible sealing element in the form of a ring or gaiter 64 is mounted between the outer frame 60 and the inner frame 62.
As best seen in FIGS. 12 and 13 , the gaiter 64 is convoluted and continuous. The material of the gaiter is flexible and impervious to air; the convoluted form and flexible material permit limited movement of the inner frame 62 relative to the outer frame 60 (and also relative to the remainder of the suction head to which it is mounted) without permitting any air flow between the inner and outer frames. Accordingly, all of the air flow from the dirt-collection chamber passes through the filter 24.
The gaiter 64 is also resilient and biases the inner frame 62 to a neutral position as shown. It will be understood that the filter support 12 is ideally oriented horizontally in the vacuum cleaner (i.e. as viewed in FIG. 13 ). Accordingly, in the neutral position the (downwards) force of gravity upon the inner frame 62 is exactly balanced by an (upwards) force provided by the gaiter 64. It will be understood that the agitator in all of the described embodiments moves the inner frame 62 and filter 24 in an upwards direction; the subsequent return or downwards movement is caused partly by the resilience of the gaiter 64 and partly by gravity. It is arranged that the gaiter and gravity can together return the inner frame 62 and filter 24 towards (or to) the neutral position sufficiently rapidly to match the impact frequency of the agitator. The agitation cycle is therefore repeated with the inner frame 62 being close to its neutral position each time it is impacted by the agitator. In other embodiments the resilience of the gaiter 64 can be supplemented (or replaced) by a separate resilient biasing means acting upon the inner frame 62.
The inner frame 62 is substantially rigid and provides the direct structural support for the filter 24. The rigidity of the inner frame 62 ensures that the movements of the inner frame which are caused by the agitator (for example the agitator 110 or 240) are transmitted to substantially the whole of the filter 24 with the minimum of loss or energy absorption.
FIGS. 11-13 show a filter support 12 without an impact tab. The filter support 12 is therefore designed for use in an embodiment such as that of FIG. 1 in which the agitator 110 directly impacts the inner frame 62. It can of course be arranged that the agitator 240 of the second embodiment directly impacts the inner frame if desired.
It will be seen from FIG. 13 that the inner frame 62 has a perforated lower wall 72 and a perforated upper wall 74. In this embodiment the configurations of the perforations differ, with the lower wall 72 having larger and fewer perforations. As regards the lower wall 72, a significant criterion is that the area of the filter 24 which is exposed to the air flow through the lower wall is maximised; accordingly, the ratio of open space to material is maximised for the lower wall 72. That criterion is less important for the upper wall 74, and a significant criterion for the upper wall 74 is that the filter should not be significantly distorted by the air flow; accordingly, the ratio of material to open space is greater in the upper wall 74.
It will be understood that an impact tab (such as the impact tab 232) could be fitted to the filter support 12, and the shape and dimensions of the filter support could be modified as necessary to match the particular dirt-collection chamber. It will be understood that the impact tab would ideally be connected to the upper wall 74 (at the clean air side) and would bridge the gaiter 64 and the outer frame 62. Impacts from the agitator are therefore communicated directly to the inner frame 62 (and to the filter 24) by way of the impact tab.
A third embodiment of the invention is shown in FIGS. 14-20 . Whilst the complete suction head of the third embodiment is not shown, it will be understood that the dirt-collection chamber 326 and agitator 340 of this embodiment could be used in a suction head similar to the suction head 104 of FIG. 1 or similar to the suction head 204 of FIGS. 2-4 , with only minor structural changes (and vice versa).
The third embodiment shares many features of the second embodiment described above. In particular, the dirt-collection chamber 326 has a filter support 312 providing its top wall, which filter support is shown in detail in FIGS. 18-20 . A filter 324 is mounted in the filter support 312. The filter support 312 has a substantially rigid outer frame 360 and a substantially rigid inner frame 362 which are connected together by a flexible gaiter 364. The suction head has an agitator 340 to agitate the inner frame 362 and dislodge dirt and debris from the filter 324.
In this embodiment, and as better seen in FIG. 15 , the agitator 340 has a lozenge-shaped impacter 342, which in this embodiment is of steel. An eccentric weight 350 has a first hole 352 therethrough, which hole receives a bolt 348 which also passes through a hole in one end of the impacter 342. Importantly, the impacter 342 can rotate around the bolt 348, and therefore relative to the eccentric weight 350. The eccentric weight 350 has a second hole 354 therethrough, which hole receives the drive shaft (not shown) of the motor 344. The eccentric weight 350 is rigidly secured to the drive shaft and rotates with the drive shaft.
The offset mounting of the impacter 342 relative to the rotation axis of the drive shaft, and the ability of the impacter to rotate about its mounting, results in an impacter 342 in the form of a flail. As the drive shaft of the motor 344 rotates the inertia of the impacter 342 causes it to adopt the position shown in FIGS. 15 and 16 , in which position its centre of mass is farthest from the rotation axis. It is arranged that the combined rotating mass of the eccentric weight 350 and the impacter 342 are substantially balanced around the rotation axis in this position so as to reduce the likelihood of damage to the motor.
The third embodiment has a single agitator 340 at one side of the dirt-collection chamber 326 and this has been found to provide suitable agitation of the filter 324. Alternative embodiments can have two or more agitators spaced around the filter 324 if desired.
As better seen in FIG. 18 , an impact tab 332 is rigidly mounted to the filter support 312, and in particular is rigidly mounted to the top perforated wall 374 of the filter support. The impact tab 332 projects downwardly into a chamber 382 at the side of the dirt-collection chamber 326 in which the impacter 342 and balancing element 350 are located. The chamber 382 is entirely located to the clean air side of the filter 324 and no part of the agitator 340 is exposed to the dirt and debris in the dirt-collection chamber 326.
As with the first and second embodiments, the dirt-collection chamber 326 can be removed from the suction head for emptying. The dirt-collection chamber 326 is removed together with the top cover 330, the filter support 312 and the filter 324; the agitator 340 and secondary motor 344 are not removed.
As with the earlier embodiments, the flexible gaiter 364 permits the inner part or frame 362 to move relative to the outer part of frame 360. The flexible gaiter 364 surrounds the inner frame 362 and prevents air flow between the inner and outer frames. The gaiter 364 is shown in more detail in FIG. 20 , and is a flexible convolute seal which in this embodiment is clamped between respective parts of the outer and inner frames. In another embodiment the gaiter is over moulded. The gaiter of the earlier embodiment can be of identical construction.
The inner frame 362 is substantially rigid and provides direct structural support for the filter 324.
The path P which is swept by the outer end of the impacter 342 as it rotates is represented in FIG. 16 and has a radius R (centred on the hole 354 at the axis of rotation of the drive shaft of the motor 344). It is arranged that the bottom end of the impact tab 332 is located inside the circle P. Accordingly, as the impacter 342 rotates it repeatedly strikes the bottom end of the impact tab 332.
The ability of the impacter 342 to rotate around the bolt 348, and its eccentric mounting, mean that the impacter 342 can move from the position (relative to the eccentric weight 350) which is shown in FIG. 16 , and can specifically move to a position in which its outer end is closer to the rotation axis than the radius R. It is arranged that the movement towards the rotation axis is sufficient to allow the impacter 342 to pass the impact tab 332 so that the motor output shaft can continue to rotate. After passing the impact tab 332 the impacter 342 returns to the fully extended position of FIG. 16 and again strikes the impact tab 332 on its next rotation. The continued rotation of the motor is therefore not prevented by the repeated impacts upon the impact tab 332.
It will be seen from FIG. 18 that the inner frame 362 has a perforated upper wall 374. The lower wall 372 is also perforated. The structure and relative size of the perforations can be different from or similar to those of the earlier embodiments of filter support, as suitable for the particular vacuum cleaner.
Whilst the agitator could operate continuously, it is preferable that it operates periodically, and ideally when there is little or no competing air flow. In preferred embodiments the impacters are actuated each time the vacuum cleaner primary motor is switched off. A short delay is provided between the primary motor switching off and actuation of the secondary agitator motor in order to permit the impeller to slow down or stop so that the air flow through the filter is stopped or at least reduced significantly.
Tests have shown that with a rate of rotation of the impacter 242, 342 of around 87 rpm, a burst of impacts lasting for a little over three seconds can dislodge a significant proportion of the fine dirt and dust which adheres to the surface of the filter 226, 326 or occupies the pores and passageways of the filter.
With the embodiment of FIG. 1 , on the other hand, between around 15 and 18 impacts from the hammer 110 (and ideally 17 impacts) has been found to be effective, with fewer impacts being significantly less effective and more impacts having a negligible benefit. The rate of rotation of the cam 116 determines the impact frequency, and an impact frequency of around 17 Hz has been found to be effective for that embodiment. Such an arrangement requires the cam motor to be actuated for only around one second after each use of the vacuum cleaner.
In one configuration of the third embodiment the maximum radius R of the path P swept by the outer end of the impacter 342 (measured from the rotation axis of the motor output shaft) is approx. 16.5 mm. The mass of the impacter 342 is between approx. 15 g and approx. 20 g. Tests with such an impacter have indicated that the optimum rotation rate for the impacter 342 (and therefore for the output shaft of the motor 244) is approximately 5,200 rpm which gives an impact rate of approximately 87 per second. Rotation rates of between approx. 4,500 rpm and approx. 6,000 rpm have also been found to be effective (with respective impact rates of approx. 75 to 100 per second). Reducing the rotation rate to approx. 3,500 rpm has been found to reduce the cleaning effectiveness and increasing the rotation rate to approx. 6,600 rpm has been found to provide no additional benefit. The same path radius, mass and range of rotation rates have also been found to be effective for the agitator 240 of FIGS. 2-10 .
It has been found that the substantially rigid inner frame 262, 362 communicates the impacts from the agitators 240, 340 to substantially all of the filter 224, 324 respectively notwithstanding that the impacters 242, 342 impact a localised region of the inner frame 262, 362.
At least some of the dirt and dust which is dislodged from the filter 224, 324 falls back into the body of the dirt- collection chamber 226, 326 and is retained within the mass of collected dirt and debris within the dirt-collection chamber. When the air flow re-commences the retained dirt and dust will not all be re-mobilized to re-engage the filter. The impacters 110, 242, 342 can therefore reduce the mass of dirt and dust which is available to coat the surface of the filter 224, 324 or to block the pores and passageways of the filter and can thereby maintain a greater air flow through the filter for a longer period of time.

Claims

1. A bagless vacuum cleaner having a dirt-collection chamber with an inlet and an outlet and a filter at its outlet, the vacuum cleaner having an agitator to agitate the filtered, the filter being mounted in a two-part filter support with a first part and a second part which can move relative to one another, the second part being mounted to move relative freely relative to the first part, the filter being mounted to the second part of the filter support.

2. A bagless vacuum cleaner according to claim 1 having an electric motor which drives an impeller to create air flow from the inlet to the outlet, the vacuum cleaner having an air duct between the filter and the impeller, in which the agitator is located in the air duct.

3. A bagless vacuum cleaner according to claim 2 in which the agitator is partly sealed in a chamber connected to the air duct.

4. (canceled)

5. A bagless vacuum cleaner according to claim 1 in which the filter is movable substantially vertically when the vacuum cleaner is located on a horizontal surface.

6. (canceled)

7. A bagless vacuum cleaner according to claim 1 in which the agitator agitates the filter support to move the filter by way of the filter support.

8. (canceled)

9. A bagless vacuum cleaner according to claim 1 in which the first part surrounds the second part.

10. A bagless vacuum cleaner according to claim 1 in which the second part is mounted to the first part by a flexible sealing element.

11. A bagless vacuum cleaner according to claim 10 in which the sealing element is resilient.

12. A bagless vacuum cleaner according to claim 1 in which the second part has a perforated first wall and a perforated second wall, with the filter located between the first and second walls.

13. A bagless vacuum cleaner according to claim 1 in which the filter support has an impact tab, and in which the agitator can engage the impact tab.

14. A bagless vacuum cleaner according to claim 13 in which the impact tab is rigid and is rigidly mounted to the filter support.

15. A bagless vacuum cleaner according to claim 14 in which the impact tab is rigidly mounted to the second part of the filter support.

16. A bagless vacuum cleaner according to claim 1 in which the dirt-collection chamber is removable, and in which the agitator remains in the vacuum cleaner when the dirt-collection chamber is removed.

17. A bagless vacuum cleaner according to claim 1 in which the agitator is electrically actuated.

18. A bagless vacuum cleaner according to claim 1 in which the agitator is actuated intermittently.

19. A bagless vacuum cleaner according to claim having an electric motor which drives an impeller to create air flow from the inlet to the outlet, in which the agitator is actuated only when the motor is switched off.

20. A bagless vacuum cleaner according to claim 19 in which the agitator is actuated each time the motor is switched off.

21. A bagless vacuum cleaner according to claim 19 in which the agitator is actuated at the end of a predetermined period after the motor has been switched off.

22. A bagless vacuum cleaner according to claim 1 in which the agitator is actuated for a predetermined period of more than three seconds.

23. A bagless vacuum cleaner according to claim 1 in which the filter is agitated at a frequency of less than 100 Hz.

24. A bagless vacuum cleaner according to claim 1 in which the agitator includes an impacter which is located adjacent to the dirt-collection chamber.

25. A bagless vacuum cleaner according to claim 24 in which the impacter is a rotating eccentric element.

26. A bagless vacuum cleaner according to claim 25 in which the impacter is eccentrically mounted relative to a rotatable drive shaft.

27. A bagless vacuum cleaner according to claim 24 in which the agitator includes a balancing element to balance the eccentricity of the impacter.

28. A bagless vacuum cleaner according to claim 27 in which the impacter is mounted to the balancing element.

29. A bagless vacuum cleaner according to claim 1 in which the agitator is located in a closed chamber of the vacuum cleaner.