Hand-held bagless vacuum cleaner

Abstract

This invention relates to a vacuum cleaner, and in particular to a hand-held bagless vacuum cleaner which does not utilise cyclonic separation or filtration. The vacuum cleaner has a body containing a motor, an impeller, a dirt-collection chamber and a filter. The area of the filter is increased by substantially spanning the body between its first end and second ends and by substantially spanning the body between opposing parts of the side wall. The filter separates the body into two defined regions, a first region comprising a dirt-collection volume in the dirt-collection chamber and a second region containing the motor and the impeller. The vacuum cleaner also has an agitator configured to dislodge dirt from the filter.

Description

[0001] HAND-HELD BAGLESS VACUUM CLEANER

[0002] FIELD OF THE INVENTION

[0003] This invention relates to a vacuum cleaner, and in particular to a bagless vacuum cleaner which does not utilise cyclonic separation or filtration. The invention is expected to have its greatest utility in relation to a “stick-vac” hand-held bagless vacuum cleaner and the following description will relate primarily to such a vacuum cleaner. The invention is nevertheless applicable to other types of vacuum cleaner.

[0004] BACKGROUND TO THE INVENTION

[0005] 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.

[0006] 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 manoeuvred during use. The operating handle is in turn connected to a flexible hose through which the air and entrained 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 and / or slides by which it may be moved across the floor (e.g. pulled by way of the hose) during the cleaning operation. Fig.1 shows the body and part of the flexible hose of two representative cylinder vacuum cleaners.

[0007] For the avoidance of doubt, the term “impeller” as used in this specification embraces all devices for creating air flow in the vacuum cleaner. The term therefore also includes fans and turbines for example.

[0008] The second class is often referred to as upright vacuum cleaners. In upright vacuum cleaners 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. The motor and the impeller may be located in the suction head or in the body. Fig.2 shows two representative upright vacuum cleaners which both have the motor and impeller in the body. 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 many 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 manoeuvred 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 (as represented in Fig.2). When released from its stored position the hose can be extended to reach the desired location.

[0009] Many cylinder vacuum cleaners, and many upright vacuum cleaners, are mains- powered or “corded”. The suction head of a cylinder vacuum cleaner, and the released end of the extendable flexible hose of an upright vacuum cleaner, are manoeuvrable 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 manoeuvrable 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. All four of the vacuum cleaners represented in Figs.1 and 2 are mains powered.

[0010] A third class of vacuum cleaner is a hand-held vacuum cleaner. Hand-held vacuum cleaners are typically battery-operated or “cordless” 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. Fig.3 shows three representative hand-held (and battery-operated) vacuum cleaners.

[0011] 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.

[0012] 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 air flow which can be generated, 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 a suction head and the body of the vacuum cleaner, in a configuration often referred to as a “stick-vac”. Vacuum cleaners of the “stick-vac” type have become increasingly popular as a replacement for a mains- powered vacuum cleaner, and many householders have a stick-vac type as their sole vacuum cleaner.

[0013] 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. A stick-vac type of vacuum cleaner with a suction head having a steering joint is described in WO2018 / 060684 for example.

[0014] 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 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 of together with the contained dirt and debris. A regular supply of new bags is therefore required for use in the vacuum cleaner, and many users nowadays wish to avoid the additional waste generated by the bags themselves.

[0015] “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. In a mains-powered vacuum cleaner the dirt-collection chamber is often 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 dirtcollection chamber is reinstalled into the body for re-use. In a battery-powered vacuum cleaner, on the other hand, the dirt-collection chamber may not be removable since the user can readily carry the whole vacuum cleaner to a site of disposal, the dirt-collection chamber having an openable door to allow the collected dirt and debris to be emptied.

[0016] 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.

[0017] The filter of WO2012 / 085567 is in two parts which are located in the suction head at the top of the dirt-collection chamber. The filter is planar and located in a removable filter support. The filter support has perforated screens and the filter lies upon the perforated screens. The main function of the perforated screens is to support the filter and maintain the planar form of the filter. Nevertheless, the large number of small holes in the screens provide some coarse filtration upstream of the filter. The filter of WO2012 / 085567 spans most of the area of the dirt-collection chamber, i.e. the area of the filter is effectively maximised. Increasing the area of the filter is highly beneficial as it increases the number of pores through which the air can pass, and therefore increases the period of use before the filter becomes sufficiently blocked by captured dirt and dust for the vacuum cleaner performance to be impaired.

[0018] WO2014 / 195711 discloses a hand-held bagless vacuum cleaner which can be configured for use as a stick-vac. In common with many bagless vacuum cleaners, WO2014 / 195711 utilises cyclonic filtration. The body of the vacuum cleaner has a generally cylindrical dirt-collection chamber. Air and entrained dirt enters the dirtcollection chamber through an air inlet at the periphery of the cylinder and a baffle causes the air to flow circumferentially around the chamber. A generally cylindrical rigid shroud is located at the centre of the cylinder and the air circulates around the shroud before passing through holes in part of the shroud. Larger pieces of dirt and debris which cannot pass through the holes in the shroud, and also smaller pieces which do not remain entrained in the air flow, are captured in the dirt-collection chamber outside the shroud. The shroud therefore effectively provides some coarse filtration.

[0019] Whilst cyclonic filtration avoids the drawbacks of disposable bags, it has its own disadvantages. One significant disadvantage is that the cyclonic action separates the larger pieces of dirt and debris from the smaller pieces of dirt and dust. The larger pieces, including in particular fibrous materials such as fluff and hair, are typically the first to be collected, in a first location of the dirt-collection chamber. Meanwhile, most or all of the smaller pieces of dirt and dust pass to a second (and perhaps further) region of the dirt-collection chamber. Collecting most or all of the fine dirt and dust together is a major disadvantage when the dirt-collection chamber is emptied because a significant proportion of what is a relatively large volume of fine particles of dust will often become airborne, perhaps as a visible cloud of dust. Airborne dust will resettle and require further cleaning, and can be damaging to health.

[0020] A further significant disadvantage of cyclonic vacuum cleaners is that their dirt-collection chambers typically contain relatively large structures such as shrouds and baffles as required to generate and utilise the cyclonic air flow. This is a particular disadvantage for hand-held cyclonic vacuum cleaners where the overall size of the vacuum cleaner and therefore the dirt-collection chamber is limited by the requirement for portability.

[0021] Another significant disadvantage is that much of the smaller pieces of dirt and dust is collected in a relatively small volume. That small volume has a relatively large surface area and a large proportion of the collected dirt and dust can readily stick to that surface. Dirt and dust which has become stuck to the surface does not fall out of the dirtcollection chamber during disposal and usually has to be removed manually. Also, the structures inside the dirt-collection chamber which generate and utilise the circulating air flow restrict the air flow path and can cause dirt and debris to become trapped, perhaps blocking the air flow path entirely. This is also a particular disadvantage for a hand-held vacuum cleaner in which the overall size of the dirtcollection chamber, and therefore the size of the air flow path, is limited by the requirement for portability.

[0022] Furthermore, the rapid rotation of the air in the dirt-collection chamber which is required for effective cyclonic separation of the dirt and debris increases the fluid friction; greater power is therefore required to maintain the required air flow for effective cleaning. An increased power requirement can be significant for a battery-powered vacuum cleaner.

[0023] Notwithstanding the cyclonic separation, cyclonic vacuum cleaners will often have a physical filter at the outlet of the dirt-collection chamber to capture the fine dirt and dust which is not separated from the air flow by the cyclonic action. In WO2014 / 195711 , for example, the filter is located inside the shroud. The filter is mounted to a flexible and resilient filter support, the filter support including a perforated central tube. Air passes through the filter and leaves the dirt-collection chamber by way of the central tube.

[0024] In WO2014 / 195711 the dirt-collection chamber can be removed from the body of the vacuum cleaner and opened to allow the disposal of the collected dirt and debris. The shroud and filter can be removed from the open dirt-collection chamber for cleaning.

[0025] In most hand-held bagless vacuum cleaners, including those utilising cyclonic separation, the filter is relatively small. This is a result of a common design compromise between seeking to maximise the available volume of the dirt-collection chamber in which dirt and debris can be collected and seeking to ensure that the hand-held vacuum cleaner is small and light enough to be portable for extended periods of use.

[0026] A consequence of using a relatively small filter is that it can become blocked by dust and dirt relatively quickly. The performance of the vacuum cleaner can deteriorate even when the filter is only partially blocked. Only the most diligent of users will typically clean the filter regularly, for example each time the dirt-collection chamber is emptied, as is required to maintain optimum performance. In practice therefore, the filters of many known hand-held bagless vacuum cleaners are too small for the vacuum cleaner to be used for every day cleaning and they are usually restricted to supplementing a mains-powered vacuum cleaner.

[0027] The reduction of performance caused by partially-blocked filters affects all types of vacuum cleaner but is usually more significant for battery-operated vacuum cleaners. Since most hand-held vacuum cleaners are battery-operated they are generally susceptible to these performance reductions. Battery-operated stick-vac type vacuum cleaners in particular require a relatively large air flow to operate effectively, for example around 15 litres per second. If the air flow drops much below around 12 litres per second the performance of the vacuum cleaner is significantly reduced. There is a compromise between a filter which can capture all or most of the fine dirt and dust and a filter which can enable the desired air flow for an acceptable length of time. The manufacturers of many battery-operated stick-vac type vacuum cleaners use filters which permit some fine dirt and dust to pass through to the exhaust rather than being captured. These airborne particulates will resettle so that further cleaning is required, and can in some circumstances be damaging to health. In addition, the users of many stick-vac type vacuum cleaners find that they have to empty the dirt-collection chamber before the dirtcollection chamber is full, and have to clean the filter(s) regularly, in order to maintain a desired level of performance.

[0028] As stated above, many cyclonic vacuum cleaners have a physical filter at the outlet of the dirt-collection chamber. The physical structures inside the dirt-collection chamber, and the use of a circulating air flow in the chamber, together effectively determine the required location for the filter. In addition, the overall size of a hand-held vacuum cleaner is limited by the requirement for portability, which in turn limits the overall size of the dirt-collection chamber. These factors all restrict the location for the filter and the size of the filter. Notwithstanding that the filter is important to the performance of the vacuum cleaner its size and location is therefore often compromised by the above factors.

[0029] SUMMARY OF THE INVENTION

[0030] Notwithstanding that the perforated screens of WO2012 / 085567 and the shroud of WO2014 / 195711 perform a coarse filtration, they are not referred to herein as “filters”. The word filter is reserved in this application for a material which is provided solely (or at least primarily) to capture dirt and dust from an air flow. The filter will typically be of foam, paper or cloth (or a combination of these) with a large number of small pores or pathways through which air can pass. Dirt and dust can be captured at the surface of the filter and within the material (e.g. the pores) of the filter. Filters are typically flexible and many are not self-supporting so that in most applications they need to be mounted in a filter support in order to maintain their desired shape. An electrostatically-charged wadding filter is one type of filter which is commonly used in vacuum cleaners. HEPA filters are also commonly used, this being an acronym for “high efficiency particulate air”, and which term is reserved for filters which achieve stringent performance targets.

[0031] One object of the present invention is to provide a hand-held bagless vacuum cleaner which can provide a sustained rate of air flow suitable for prolonged operation in a stick- vac configuration.

[0032] Another object of the invention is to provide a hand-held vacuum cleaner in which most or all of the fine dirt and dust is captured by the filter(s) and little or no dirt and dust passes to the exhaust. Another object of the present invention is to provide a hand-held vacuum cleaner with a filter which is significantly larger than the filter of known hand-held vacuum cleaners.

[0033] Another object of the present invention is to provide a hand-held vacuum cleaner which does not utilise cyclonic filtration or separation and thereby avoids the above-stated disadvantages.

[0034] According to a first aspect of the invention there is provided a hand-held bagless vacuum cleaner having a body containing a motor, an impeller, a dirt-collection chamber and a filter, the body having a first end, a second end and a side wall between the first end and the second end, the dirt-collection chamber having an air inlet; the distance between the first end and the second end being substantially the largest dimension of the body and the filter substantially spanning the body between the first end and the second end; and the filter also substantially spanning the body between opposing parts of the side wall, the distance between the opposing parts of the side wall being substantially the largest dimension across the body; the filter separating the body into two regions, a first region comprising a dirt-collection volume in the dirt-collection chamber and a second region containing the motor and the impeller; the vacuum cleaner having an agitator configured to dislodge dirt from the filter, the filter being mounted so as to be substantially freely movable when agitated.

[0035] Alternatively stated, the filter is substantially as long as the body and substantially as wide as the body. Accordingly, the filter spans the largest cross-section of the body and the filter area is therefore maximised for the dimensions of the body. Also, the body is preferably configured substantially to maximise the area of the filter.

[0036] Preferably, the dirt-collection chamber is not removable from the body. The side wall of the dirt-collection chamber can therefore provide a part of the side wall of the body to further enable the area of the filter to be maximised for the dimensions of the body.

[0037] It will be understood that maximising the filter area is beneficial in maximising the air flow through the vacuum cleaner without compromising the filter performance, and is also beneficial in maximising the periods of use before it becomes necessary to clean the filter.

[0038] This arrangement is in direct contrast to the known hand-held vacuum cleaners, including hand-held cyclonic vacuum cleaners, which have filters which typically extend across and / or along only a relatively small proportion of the area of the body and are therefore of relatively small area in comparison to the body.

[0039] Preferably, the filter is substantially planar. According to a second aspect of the invention there is provided a hand-held vacuum cleaner having a body containing a motor, an impeller and a dirt-collection chamber, the dirt-collection chamber having a primary filter, a secondary filter and an air gap between the primary filter and the secondary filter.

[0040] The vacuum cleaner according to this aspect therefore has two (separated) filters, the secondary filter being downstream of the primary filter. Air therefore passes through the primary filter at which some of the dirt and dust is captured before passing through the secondary filter at which all (or at least most) of the remaining dirt and dust is captured.

[0041] It is known to provide multi-part filters, i.e. single filters with multiple layers of differing construction and therefore differing filtration properties. The multi-part filters are designed to capture increasingly fine dirt and dust as that is carried through the filter by the airflow. The provision of an air gap according to this aspect of the invention effectively separates the primary and secondary filters and enables dirt and dust which is captured at or close to the surface of the secondary filter to be more readily removed (that dirt and dust would be more deeply buried in a known multi-part filter and would therefore be significantly harder to remove).

[0042] The primary and secondary filters are preferably of different materials and filtration characteristics. Providing two filters of different materials enables the performance characteristics of the filters to be balanced so that together their performance can be optimised.

[0043] For the avoidance of doubt, the invention according to this second aspect provides two filters upstream of the impeller and motor. Some hand-held vacuum cleaners have two filters, specifically a primary filter upstream of the impeller and motor and a secondary (exhaust) filter downstream of the impeller and motor (which exhaust filter is primarily provided to capture dust generated by the carbon brushes of the motor).

[0044] Preferably, the secondary filter is a HEPA filter. The filtration performance of the present invention can therefore match the performance of many mains-powered vacuum cleaners and can significantly exceed the performance of many battery-powered (and / or hand-held) vacuum cleaners.

[0045] Preferably, the hand-held vacuum cleaner has an agitator for the primary filter and / or the secondary filter. The agitator may be similar to that described in WO2022 / 264108.

[0046] Preferably, at least the primary filter is located in a substantially rigid filter support. Alternatively stated, the filter support is self-supporting and can maintain its own structural shape and also maintain the structural shape of the primary filter. It will be appreciated that mounting the filter in a substantially rigid filter support can increase the effectiveness of an agitator as is described in that earlier patent application. The combination of separated primary and secondary filters and agitation to remove dirt from the filters is particularly beneficial. As above stated, with separated filters more of the dirt and dust can be captured at or close to the surface of the filters and less of the dirt and dust passes through the surface layers of filter material before being captured. Agitating the filters can dislodge dirt and dust from the surface layers whereas dirt and dust which has passed through the surface layers may not be dislodged and instead may remain within the material (or pores) of the filter and partially block the filter.

[0047] Desirably, the filter support (and filter) are removably mounted in the body of the vacuum cleaner. The filter support and filter can thereby be removed for periodic cleaning and replacement as desired.

[0048] Desirably, the filter support has a first perforated wall and a second perforated wall, the filter being located between the first and second perforated walls. The perforations in the walls are preferably relatively very large. It is therefore not intended that the perforated walls of the filter support perform any appreciable filtration and instead act merely to maintain the structural shape of the filter in use. Increasing the size of the perforations, and conversely reducing the overall area of the wall segments between the perforations, increases the area of the filter through which air can flow.

[0049] Preferably, the secondary filter is formed of paper in pleated form (in common with many HEPA filters) and whilst such a filter is flexible its pleated form can provide sufficient structural rigidity to avoid the requirement for mechanical support at the upstream and downstream sides of the secondary filter.

[0050] Desirably, the secondary filter is removably mounted in the body of the vacuum cleaner. The secondary filter can thereby be removed for periodic cleaning and replacement as desired. Preferably, the secondary filter is mounted to a rigid collar which facilitates handling of the removed filter and also facilitates installation of the filter in the body of the vacuum cleaner.

[0051] The primary filter has an effective area through which air can flow and the secondary filter has an effective area through which air can flow. Desirably, the effective area of the secondary filter is substantially the same as the effective area of the primary filter. Providing substantially equal effective areas can better facilitate the balancing of the filter performance between the primary and secondary filters and can thereby help to maximise the overall filtration performance.

[0052] Preferably, the secondary filter is substantially parallel with the primary filter. There is therefore a substantially uniform air gap between the primary and secondary filters across the area of the filters. It will be understood that fibrous debris including in particular fluff and hair will be captured by the primary filter. Small pieces of dirt and dust which might otherwise be able to pass through the primary filter will be captured by the fibrous material which has itself been captured by the primary filter. As the volume of fibrous material upstream of the primary filter builds up more of the fine dirt and dust is captured.

[0053] Accordingly, and in direct contrast to vacuum cleaners utilising a cyclonic action, the present invention does not seek to separate the smaller pieces of dirt and dust from the larger pieces of dirt and debris. Instead, the invention allows the fine dirt and dust to collect with the larger pieces of dirt and debris, and in particular to become trapped amongst the fibres of the collected fibrous materials. In practice much of the fine dirt and dust will become trapped amongst the fibres and only a small proportion will pass through the primary filter, increasing the duration of use before the primary filter becomes blocked by collected dirt and dust. In addition, when the dirt-collection chamber is emptied, most of the fine dirt and dust will remain trapped amongst the fibres and will be less likely to become airborne; only that relatively small proportion of fine dirt and dust which has passed through the primary filter might become airborne upon disposal.

[0054] According to a third aspect of the invention there is provided a hand-held vacuum cleaner having a body containing a motor, an impeller, a dirt-collection chamber and at least one filter, the filter being substantially planar.

[0055] As stated above, the filter of WO2014 / 195711 is cylindrical and a cylindrical or tubular shape for the filter is typical for many hand-held vacuum cleaners. The provision of a planar filter has significant benefits in a hand-held vacuum cleaner. Firstly, a planar filter can readily be packaged in the body of the vacuum cleaner with little disruption to other components and minimal design compromise. Secondly, the orientation of a planar filter can readily be reversed in order to extend the operational life of the filter. Thirdly, a planar filter enables easy removal and replacement for periodic cleaning. Fourthly, a planar filter can effectively separate the body of the vacuum cleaner into two regions, a first region housing the electrical and mechanical components and a second region comprising a collection volume for dirt and debris.

[0056] In embodiments sharing the second and third aspects of the invention the secondary filter is preferably substantially planar which provides the same or similar benefits.

[0057] During use of the vacuum cleaner, particularly when configured as a stick-vac, it is preferably arranged that the filter is substantially horizontal and is located above the collection volume of the dirt-collection chamber. The vacuum cleaner can therefore share the benefits of the filter location and orientation which are stated for WO2012 / 085567. Preferably, the body has a nozzle at the first end. In known fashion the nozzle can be connected to cleaning tools such as a dust brush and a crevice tool. The nozzle can also be connected to a suction head by way of a rigid tube in a stick-vac configuration. Desirably, the nozzle is connected directly to the air inlet of the dirt-collection chamber and there are no structures or restrictions in the air flow path from the nozzle to the dirtcollection chamber. Preferably, there is an acute angle between the axis of the nozzle and the longitudinal axis of the body, desirably a shallow acute angle, ideally less than approximately 40°. A shallow acute angle between the axis of the nozzle and the axis of the body minimises the deviation of the air flow as it passes from the nozzle into the dirt-collection chamber. It can also be arranged that the rigid tube which is connected to the nozzle is linear and aligned with the nozzle whereby the air can flow from the suction head to the dirt-collection chamber with a minimum of deviation. It will be understood that reducing the restrictions and deviations of the air flow reduces the pumping losses and also reduces the likelihood that any of the entrained dirt and debris will escape the air flow upstream of the dirt-collection chamber.

[0058] Preferably, the air inlet is located at the first end. Preferably also, the means by which the collected dirt and dust can be emptied from the dirt-collection chamber is located at the second end. The means by which the collected dirt and dust is emptied is preferably an openable panel. Preferably therefore the air inlet and the openable panel are at opposing ends of the dirt-collection chamber. This has the significant benefit that the air flow (and entrained dirt) initially moves through the dirt-collection chamber from the air inlet towards the openable panel. In practice this air flow pushes collected dirt and debris towards (and against) the panel. The collected dirt and debris more readily falls out of the dirt-collection chamber when the panel is subsequently opened.

[0059] Preferably, the cross-sectional area of the collection volume of the dirt-collection chamber increases away from the air inlet (and towards the openable panel). It will be understood that increasing the cross-sectional area of the air flow path reduces the speed of the air flow which encourages dirt and debris to escape the air flow. Dirt and debris which is no longer entrained in the air flow can readily be collected upstream of the filter.

[0060] Preferably, the cross-sectional area of the (first) collection volume upstream of the primary filter preferably increases (and ideally substantially uniformly increases) along the length of the dirt-collection chamber from the first (air inlet) end to the second (openable panel) end. Such a gradually tapering collection volume facilitates emptying of collected dirt and dust when the openable panel is opened.

[0061] As above stated, the present invention does not rely upon cyclonic separation or filtration. The dirt-collection chamber upstream of the filter therefore does not need to contain any structures to generate or utilise a circulating air flow. Desirably, the dirtcollection chamber does not contain any baffles or other structures configured to deflect or re-direct the air flow. In a preferred configuration the vacuum cleaner has the following components and characteristics. A body which is generally cylindrical and with a first end, a second end and a surrounding side wall. A nozzle at the first end connected directly to an air inlet of a dirt-collection chamber and an openable panel for emptying the dirt-collection chamber. The dirt-collection chamber substantially spans the body from the first end to the second end. At least one filter substantially spans the body from the first end to the second end. The at least one filter also substantially spans the body between opposing parts of the side wall. The at least one filter effectively separates the body into two parts, one part (upstream of the filter) being mostly hollow and comprising a collection volume of the dirt-collection chamber, the other part (downstream of the filter) containing the electrical and mechanical components, namely the motor and the impeller (and the battery if present). The body preferably has a carrying handle which is located on the other part of the body, i.e. at the downstream side of the filter.

[0062] According to a fourth aspect of the invention there is provided a hand-held vacuum cleaner having a body containing a motor, an impeller, a dirt-collection chamber, a primary filter and a secondary filter, the dirt-collection chamber having a collection volume upstream of the primary filter and a further collection volume between the primary filter and the secondary filter, the dirt-collection chamber having an emptying means by which the dirt-collection chamber can be emptied, in which the emptying means opens both of the collection volumes.

[0063] According to the fourth aspect therefore, the emptying means allows dirt and dust which has been captured by the primary filter, and dirt and dust which has been captured by the secondary filter, to be emptied at the same time and it is not necessary to empty the two collection volumes separately. Accordingly, the single emptying means (for example an openable panel) can enable dirt to be emptied from the (first) collection volume upstream of the primary filter, and from the (second) collection volume between the primary filter and the secondary filter, together.

[0064] Preferably, the emptying means is an openable panel having a sealing element which in the closed condition separates the collection volumes. Accordingly, when the panel is closed air must pass through the filters to pass from one collection volume to the other.

[0065] Optional features which are described in relation to one aspect of the invention can be utilised with the other aspects of the invention for which they are compatible. Accordingly, not all of the optional features for each aspect are set out in order to avoid unnecessary repetition. BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0066] The invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which:

[0067] Fig.1 shows the body and part of the flexible hose of two representative corded cylinder vacuum cleaners;

[0068] Fig.2 shows two representative corded upright vacuum cleaners;

[0069] Fig.3 shows three representative cordless hand-held vacuum cleaners;

[0070] Fig.4 shows a side view of a hand-held vacuum cleaner according to the present invention;

[0071] Fig.5 shows a side sectional view of part of the vacuum cleaner of Fig.4;

[0072] Fig.6 shows a view similar to Fig.5 but with the openable panel opened;

[0073] Fig.7 shows a perspective view of the vacuum cleaner of Fig.4, with the openable panel opened;

[0074] Fig.8 shows a part of the vacuum cleaner of Fig.4 including the primary filter;

[0075] Fig.9 shows a part of the vacuum cleaner of Fig.4 including the secondary filter;

[0076] Fig .10 shows the primary filter and its filter support;

[0077] Fig .11 shows a sectional view of the primary filter and its filter support; and

[0078] Fig .12 shows a side sectional view of the primary and secondary filters and an agitator for the primary filter.

[0079] DETAILED DESCRIPTION

[0080] Figs. 1 -3 show representative examples of the three types of known vacuum cleaners described above. These examples are shown primarily to demonstrate the significant structural differences which the present invention provides over the known vacuum cleaners, in particular in the relative size and location of the filter, and which provide the identified significant technical benefits. As stated, cylinder vacuum cleaners A and B shown in Fig .1 , and the upright vacuum cleaners C and D shown in Fig.2 are mains powered or corded. The hand-held vacuum cleaners E, F and G shown in Fig.3 are battery powered or cordless.

[0081] The body of both of the cylinder vacuum cleaners A and B contains a disposable bag into which the dirt and debris is collected for disposal. The upright vacuum cleaner C also has a disposable bag whereas the upright vacuum cleaner D has a cyclonic separator.

[0082] The hand-held vacuum cleaner E is designed primarily to supplement a mains-powered vacuum cleaner and is suitable for spot cleaning and the like. The vacuum cleaner E has a filter in the form of a small reusable bag located immediately adjacent to the nozzle into which dirt and debris is collected. The hand-held vacuum cleaners F and G are both suited to longer-term operation and a rigid tube and suction head can be connected to the nozzle of each of these vacuum cleaners for use in a stick-vac configuration. The hand-held vacuum cleaner F has a bag into which dirt and debris is collected whereas the hand-held vacuum cleaner G has a cyclonic separator.

[0083] The vacuum cleaner 10 according to the present invention is shown in Fig.4. The vacuum cleaner 10 has a body 12 with a nozzle 14 and a carrying handle 16. It will be understood that the vacuum cleaner 10 can be used in the configuration as shown, with the user manipulating the vacuum cleaner by way of the handle 16 so that the nozzle 14 is manoeuvred adjacent to the dirt and debris to be collected.

[0084] In common with many vacuum cleaners, attachments (such as a dust brush and a crevice tool for example) can be fitted to the nozzle 14 to enhance the cleaning in particular circumstances. In addition, one end of a rigid tube (not shown) can be fitted to the nozzle 14, the other end of which tube is connected to a suction head (perhaps by way of a steering joint) so that the vacuum cleaner can be operated as a stick-vac type of vacuum cleaner. The detailed structure of the attachments which may be fitted to the vacuum cleaner 10 are not relevant to the present invention and will not be described further.

[0085] The nozzle 14 is located at a first end 20 of the body 12. The body 12 also has a second end 22, a side wall 24 and a longitudinal axis A-A. In this embodiment the side wall 24 is curved so that the body 12 is of generally cylindrical form, albeit not of circular or consistent cross-section. The first end 20, second end 22 and side wall 24 provide the outer wall of the body 12 and contain the components of the vacuum cleaner which are shown in the sectional views and described below.

[0086] In known fashion, and as seen in the sectional view of Fig.5, the body 12 contains a battery pack 26, a motor 28 and an impeller 30. The battery pack is rechargeable and in use powers the motor which rotates the impeller and creates an air flow from the nozzle 14, through the vacuum cleaner and to an exhaust (not shown). Again, the detailed structure of the battery pack, motor and impeller are not relevant to the invention and will not be described further.

[0087] The nozzle 14 is connected to an air inlet 32 of a dirt-collection chamber 34. As is seen in Figs.5 and 6, the nozzle 14 is effectively a continuation of a first collection volume 36 of the dirt-collection chamber 34 and there are no structures or restrictions to impair the air flow from the nozzle 14 through the air inlet 32 and into the first collection volume 36 (the lines shown in the collection volume 36 in Fig.5 are mould lines or junctions between surfaces - as is more apparent from Fig.6 the nozzle 14, air inlet 32 and collection volume 36 are hollow without any internal restrictions or structures).

[0088] As is also seen in Fig.5, the nozzle 14 is at a shallow acute angle a to the longitudinal axis A-A. In this embodiment the angle a is slightly less than 40°. It will be understood that in use in a stick-vac configuration the vacuum cleaner 10 would be oriented approximately 90° anti-clockwise from the orientation of Figs. 4 and 5 and a floorengaging suction head (not shown) would be connected to the nozzle 14 by way of a rigid tube (also not shown); the rigid tube can be linear and aligned with the nozzle 14 whereby the only deviation of the air flow between the suction head and the dirtcollection chamber 34 is the bend around the shallow angle a of the nozzle 14 as shown.

[0089] The dirt-collection chamber 34 is not removable from the body 12 and can be integrated into the structure of the body. In particular, a part of the side wall 24 of the body 12 is also the side wall of the dirt-collection chamber 34. In addition, the dirt-collection chamber 34 extends almost the full length of the body 12 from the first end 20 to the second end 22.

[0090] The dirt-collection chamber 34 has a primary filter 42 and a secondary filter 44. There is an air gap 46 between the primary filter 42 and the secondary filter 44, and a further air gap 48 between the secondary filter and the impeller. The areas of the air gaps 46 and 48 are at least as large as the primary filter 42 and secondary filter 44 whereby air can flow through the full area of both filters, for example in a linear direction from the left-hand side to the right-hand side of the sheet as drawn in Fig.5.

[0091] In this embodiment the primary filter 42 is a foam filter and the secondary filter 44 is a pleated paper HEPA filter. Different embodiments can have different types of filter(s) but this arrangement is preferred.

[0092] In use, air and entrained dirt and debris is drawn into the body 12 through the nozzle 14 and pass into the first collection volume 36 of the dirt-collection chamber 34. The absence of any structures or restrictions in the collection volume 36 results in the air flow (at least initially) being substantially linear along the length of the first collection volume 36 substantially aligned with the longitudinal axis A-A. The cross-sectional area at the air inlet 32 is slightly larger than the cross-sectional area of the nozzle 14. In addition, the cross-sectional area of the first collection volume 36 increases (gradually and generally smoothly) from the air inlet 32 at the first end 20 to the second end 22. This results in the air slowing down as it moves into and along the first collection volume 36. The larger and heavier pieces of dirt and debris which can no longer be entrained by the slowing air flow fall to the bottom of the first collection volume 36.

[0093] In addition, hair, fluff and the like which cannot pass through the primary filter 42 remain in the first collection volume 36. The continued air flow entering through the air inlet 32 pushes the collected hair and fluff (and other dirt and debris) towards the second end 22. In addition, as air passes through the collected hair and fluff much of the dirt and dust entrained in that air collects amongst the fibrous material and is retained in the first collection volume 36. The proportion of the air flow which passes through the collected fibrous materials, and consequently the proportion of the entrained dirt and dust which is captured by the fibrous materials, increases as more fibrous materials are collected in the first collection volume 36 upstream of the primary filter 42.

[0094] The smallest pieces of dirt and dust which pass through the primary filter 42 remain entrained in the air flow as it crosses the air gap 46. The air flows through the secondary filter 44 and most if not all of the remaining dirt and dust is captured at, or close to, the surface of the secondary filter 44. The air gap 46 therefore provides a second collection volume of the dirt-collection chamber 34.

[0095] The dirt and dust which is not captured at the surface of the secondary filter 44 is captured in the material of that filter so that little if any dirt and dust passes to the air gap 48 (in common with the action of other HEPA filters).

[0096] An openable panel 52 is hingedly mounted at the second end 22 of the body 12 and closes the second end of the dirt-collection chamber 34. Fig. 5 shows the panel 52 in its closed position whereas Figs. 6 and 7 show the panel 52 in its open position. The panel 52 is held closed by a spring latch 50 in known fashion. The spring latch can be released by way of a slide panel 54 when it is desired to empty the collected dirt and debris.

[0097] As shown in Figs. 6 and 7, the panel 52 opens to the first collection volume 36 and also to the second collection volume 46. Accordingly, when the panel 52 is opened dirt and debris which has been collected in both of these collection volumes can be emptied together.

[0098] As shown most clearly in Fig.5, the first collection volume 36 is tapered and its cross- sectional area increases towards the panel 52, which increases the likelihood of all of the collected dirt and debris falling out of the collection volume 36 when the panel 52 is opened.

[0099] Notwithstanding that the second collection volume 46 will contain dirt and dust with little or no fibrous material, the danger from that dirt and dust becoming airborne is significantly reduced over the known hand-held vacuum cleaners. A significant proportion of the dirt and dust which is collected by the vacuum cleaner 10 will be held amongst the fibrous material in the first collection volume 36; that fibrous material, dirt and dust will be pushed against the panel 52 by the air flow and can often be removed as a single partially-compressed mass. The quantity of dirt and dust which might become airborne when the panel 52 is opened is therefore significantly reduced.

[0100] In addition, the increased likelihood that the collected dirt and debris will fall out of the dirt-collection chamber 34, and in particular will fall out of first collection volume 36, rather than having to be grasped and pulled out by the user, further reduces the likelihood that some of the dirt and dust will become airborne.

[0101] Figs. 8 and 9 show respective parts of the body 12 of the vacuum cleaner 10 to highlight the configuration and location of the primary and secondary filters 42 and 44. It will be seen from Fig.8 that the primary filter 42 is substantially planar and spans most of the distance between the first end 20 and the second end 22 of the body 12. The primary filter 42 also spans most of the distance between opposing parts of the side wall 24. Accordingly, the primary filter 42 is located at (or at least close to) the part of the body 12 having the largest cross-sectional area, allowing the area of the primary filter 42 to be effectively maximised for the dimensions of the body 12.

[0102] It will be understood from Figs. 6 and 9 that the secondary filter 42 is substantially planar and extends close to the first end 20 of the body 12. Whilst some of the secondary filter is hidden from view in Fig.9 it will be understood from Figs.5 and 6 that the air gap 48 and secondary filter 44 also extend close to the second end 22. The secondary filter 44 also spans most of the distance between opposing parts of the side wall 24. The secondary filter 44 is also located at (or at least close to) the part of the body 12 having the largest cross-sectional area and accordingly the area of the secondary filter 44 is effectively maximised for the dimensions of the body 12.

[0103] It is also arranged that the area of the secondary filter 44 is substantially the same as the area of the primary filter 42.

[0104] The filters 42, 44 effectively separate the body 12 into two regions. The first region (to the right of the secondary filter 44 as drawn in Fig.5) contains all of the mechanical and electrical components, which components can if desired be assembled and installed as a compact and neat sub-assembly. The second region (to the left of the primary filter 42 as drawn in Fig.5) comprises most of the dirt-collection chamber and contains only those components necessary for the separation and storage of dirt.

[0105] As shown in the drawings the primary filter 42 and the secondary filter 44 are substantially parallel, i.e. the width of the air gap 46 between the filters is substantially consistent across the areas of the filters. Providing a uniform air gap 46, and furthermore providing a small air gap 46, enables both of the primary and secondary filters to be located close to the part of the body having the largest cross-section.

[0106] It will be understood that the drawings do not show the vacuum cleaner in its normal orientation of use (although it can be used in any orientation). As explained above, in a normal orientation of use, especially when in a stick-vac configuration, the longitudinal axis A-A would be approximately horizontal and the nozzle 14 (and the connected rigid tube which is not shown) angled downwardly towards the floor. In such an orientation the primary filter 42 is substantially horizontal and is located above the first collection volume 36. Similarly, the secondary filter 44 is substantially horizontal and is located above the second collection volume 46. Accordingly, gravity helps to dislodge dirt, debris and dust which have been captured at the surfaces of the respective filters, in particular when the air flow is turned off.

[0107] Whilst it would be possible to increase the area of the primary and / or secondary filter by making the filters curved, that would require an increase in the size of the body 12. Alternatively, if the body is not increased in size at least one of the collection volumes would need to be reduced in size. Increasing the area of the filters would therefore require a compromise in another part of the vacuum cleaner. The use of substantially planar filters is therefore preferred as it maximises the filter area with the smallest impact on other components of the vacuum cleaner.

[0108] It will be understood that a filter of foam is flexible and is not self-supporting. The primary filter 42 is therefore mounted in a filter support 56 as shown in Figs. 10 and 1 1 . The filter support 56 has a perforated first wall 58 and a perforated second wall 60, the perforations being separated by respective wall segments. The walls 58 and 60 in this embodiment are identical but that is not necessarily the case. The size of the perforations is maximised (and the thickness of the wall segments is minimised) so as to maximise the proportion of open space in the walls 58 and 60 and thereby minimise the disruption to air flow through the primary filter 42 which is located between the walls. The walls are nevertheless sufficiently rigid to maintain their planar form, and importantly to maintain the planar form of the primary filter 42.

[0109] The walls 58 and 60 are connected at their outer edges and together provide a substantially rigid filter support 56. The filter support 56 is connected to a surrounding collar 62 by way of a flexible gaiter 64. The gaiter 64 is impermeable to air but is flexible and enables the filter support 56, and importantly the primary filter 42, to be agitated by an agitator or impacter 66 (Fig.12). As is described in patent application WO 2022 / 264108, the agitator 66 can repeatedly agitate or shake the filter support 56 to dislodge collected dirt and dust from the primary filter 42.

[0110] Similarly to the agitator described in WO 2022 / 264108, the agitator 66 can remove dirt and dust from the surface and from the material of the primary filter 42 without removal of the filter from the body 12. Nevertheless, in this embodiment it is possible to remove the filter support 56 and surrounding collar 62 for periodic cleaning or replacement of the primary filter 42 when required. Fig.7 in particular shows a release button 68 which can be pressed to release the collar 62 and allow the filter support 56 to be slid out of the body 12 by way of the opening at the second end 22.

[0111] It will be understood that a planar filter and filter support are easier to remove from the body 12 than would be the case for a curved filter and filter support. Also, it can be arranged that the filter support 56 and primary filter 42 are reversible, i.e. they can be inserted into the body 12 in two opposing orientations, which can extend the working life of the filter.

[0112] It will be understood that when the primary filter 42 and filter support 56 have been removed from the body 12, access can be obtained to the secondary filter 44. The secondary filter 44 is of pleated paper and is sufficiently self-supporting not to require a (perforated) filter support similar to that of the primary filter. The secondary filter 44 is nevertheless mounted to a rigid collar 70 as seen in Figs.9 and 12. It is arranged that the collar 70 and secondary filter 44 can be removed together from the body 12 for periodic cleaning and / or replacement when required.

Claims

CLAIMS1 . A hand-held bagless vacuum cleaner having a body containing a motor, an impeller, a dirt-collection chamber and a filter, the body having a first end, a second end and a side wall between the first end and the second end, the dirt-collection chamber having an air inlet; the distance between the first end and the second end being substantially the largest dimension of the body and the filter substantially spanning the body between the first end and the second end; the filter also substantially spanning the body between opposing parts of the side wall, the distance between the opposing parts of the side wall being substantially the largest dimension across the body; the filter separating the body into two defined regions, a first region comprising a dirt-collection volume in the dirt-collection chamber and a second region containing the motor and the impeller; the vacuum cleaner having an agitator configured to dislodge dirt from the filter, the filter being mounted so as to be substantially freely movable when agitated.

2. The hand-held bagless vacuum cleaner according to claim 1 in which the body is configured substantially to maximise the area of the filter.

3. The hand-held bagless vacuum cleaner according to claim 1 or claim 2 in which the dirt-collection chamber is not removable from the body.

4. The hand-held bagless vacuum cleaner according to claim 3 in which part of the side wall of the body provides a part of a side wall of the dirt-collection chamber.

5. The hand-held bagless vacuum cleaner according to any one of claims 1 -4 in which the filter is substantially planar.

6. The hand-held bagless vacuum cleaner according to any one of claims 1 -5 in which the filter is located in a substantially rigid filter support which filter support is substantially freely movable relative to the body, and in which the agitator is configured to agitate the filter support.

7. The hand-held bagless vacuum cleaner according to any one of claims 1 -6 in which the filter is a primary filter and in which the vacuum cleaner has a secondary filter, with an air gap between the primary filter and the secondary filter.

8. The hand-held bagless vacuum cleaner according to claim 7 in which the primary and secondary filters are of different materials and different filtration characteristics.

9. The hand-held bagless vacuum cleaner according to claim 7 or claim 8 in which the secondary filter is a HEPA filter.

10. The hand-held bagless vacuum cleaner according to any one of claims 7-9 in which the primary filter and the secondary filter are removably mounted in the body.

11. The hand-held bagless vacuum cleaner according to any one of claims 7-10 in which the primary filter has an effective area through which air can flow and the secondary filter has an effective area through which air can flow, and in which the effective area of the secondary filter is substantially the same as the effective area of the primary filter.

12. The hand-held bagless vacuum cleaner according to any one of claims 7-12 in which the secondary filter is substantially planar.

13. The hand-held bagless vacuum cleaner according to any one of claims 7-12 in which the dirt-collection chamber has a dirt-collection volume upstream of the primary filter and a further dirt-collection volume between the primary filter and the secondary filter, and in which dirt collected in both dirt-collection volumes can be emptied by way of the openable panel.

14. The hand-held bagless vacuum cleaner according to any one of claims 1 -13 in which the air inlet is located at the first end of the body, and in which the cross- sectional area of the dirt-collection chamber increases in the direction from the first end to the second end.

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