GB2589712A

GB2589712A - Vacuum cleaner and method of operation

Info

Publication number: GB2589712A
Application number: GB2014424.2A
Authority: GB
Inventors: Gerald Grey Nicholas; Williams Tommy; Ghanizadeh Abry Morteza
Original assignee: Grey Technology Ltd
Current assignee: Grey Technology Ltd
Priority date: 2019-09-12
Filing date: 2020-09-14
Publication date: 2021-06-09
Also published as: GB201913134D0; GB202014424D0

Abstract

A vacuum cleaner comprises a dirt-collection chamber adapted to accommodate a disposable bag, the vacuum cleaner having an agitator 32 configured and positioned to agitate the disposable bag in the dirt collection chamber. The agitator may include an impacter 34 and is preferably actuated intermittently and is only actuated when the motor is switched off. The agitator may be actuated at the end of a delay after the motor has been switched off. The agitator preferably comprises one or more permanent magnets and a cooperating electrical coil. The vacuum cleaner is preferably battery operated. A method of operation of a vacuum cleaner having a dirt-collection chamber, a disposable bag in the dirt-collection chamber, and an agitator, the method of operation including actuating the agitator to agitate the disposable bag in the dirt collection chamber.

Description

VACUUM CLEANER AND METHOD OF OPERATION

FIELD OF THE INVENTION s

This invention relates to a vacuum cleaner and to a method of operation, and in particular to a vacuum cleaner in which dirt and debris is collected in a disposable bag.

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 which in turn is 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 pulled across the floor during the cleaning operation.

For the avoidance of doubt, the term "impeller" as used in this specification 30 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, impeller and dirt-collection chamber are carried by, or in some cases are integral with, the operating handle, so that the body containing the motor, impeller and the dirt-collection chamber typically lie 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 io 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 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. 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 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.

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.

to 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.

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, typically by way of a cyclonic separator. 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.

It is recognised that the bag and the cyclonic separator may not capture very fine dirt and dust and a second stage filter is often included, usually upstream of the impeller.

The wall of the disposable bags used in bagged vacuum cleaners is necessarily porous. It is a recognised disadvantage of bagged vacuum cleaners that the wall typically becomes less porous during use as more and more of the pores of the bag through which the air can pass become blocked by fine dust and dirt. As the pores become blocked the air flow through the wall of the bag reduces. In addition, as the bag is filled at least some of the air passes through the collected dirt and debris in the interior of the bag, further reducing the air flow.

The reduction in air flow will, however, depend to some extent upon the type of dirt and debris which is being collected. The reduction in air flow will differ between a bag which is filled mostly with hair and fluff, a bag which is filled mostly with fine dust or other small-scale material, and a bag which is filled mostly with paper or other large-scale material. Collected material which does not block the pores will have a significantly lesser effect upon the air flow than collected material which blocks the pores.

It is sometimes stated that bagless vacuum cleaners are more environmentally friendly than bagged vacuum cleaners since they do not suffer the reduction in performance as the dirt-collection chamber becomes filled and the pores become blocked. Nevertheless, many users prefer bagged vacuum cleaners as the disposal of the collected dirt is much easier and cleaner. Thus, when emptying the dirt-collection chamber of a bagless vacuum cleaner it is known for some of the dust and dirt (particularly fine dust) to become airborne as the dirt-collection 5 chamber is emptied into a waste container, and even the most diligent of users will find it difficult (if not impossible) to empty a bagless vacuum cleaner without at least some of the dust becoming airborne. Dust which becomes airborne will usually not enter the waste container and may be inhaled which can be damaging to health. Alternatively, the airborne dust will typically settle on other surfaces and io need to be re-collected, perhaps by re-use of the vacuum cleaner, which will diminish the perceived environmental benefits of the bagless vacuum cleaner.

It is common to provide the dirt-collection chamber of a bagless vacuum cleaner with a transparent wall so that the user can readily and directly see how full the dirt-collection chamber is becoming and can empty the dirt-collection chamber as and when required. A transparent wall for the dirt-collection chamber is of no benefit for a bagged vacuum cleaner, however, since the bag is opaque. The manufacturers of bagged vacuum cleaners therefore provide other means to alert the user to a full bag. One of the known means is to provide an air flow sensor to measure the rate of air flow through the bag. As above stated, the air flow will decrease as the bag fills so that the air flow can be utilised as an indicator of the amount of dirt and debris in the bag.

As also stated above, however, the reduction in air flow depends upon the type of dirt and debris which is collected so that air flow sensors are not always reliable in practice. In particular, if a bagged vacuum cleaner is used to collect dirt and debris of which a large proportion is fine dust, the airflow will decrease significantly and an air flow sensor can alert a user to empty a bag which is only partly full.

Reductions in performance as the vacuum cleaner is used are 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 larger air flow than is typically possible with a battery powered vacuum cleaner. An air flow which is reduced because many of the pores in a disposable bag 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.

There are bagged and bagless vacuum cleaners of all three of the broad classes mentioned above. The present invention is suitable for use with all types of to vacuum cleaner incorporating a disposable bag.

SUMMARY OF THE INVENTION

One object of the present invention is to avoid or diminish the performance reduction of a bagged vacuum cleaner as the bag is filled. An ancilliary object is to improve the performance of an air flow sensor in a bagged vacuum cleaner by avoiding or reducing the likelihood that the air flow diminishes significantly before the bag is full.

According to the invention there is provided a vacuum cleaner having a dirt-collection chamber adapted to accommodate a disposable bag, the vacuum cleaner having an agitator configured and positioned to agitate the disposable bag in the dirt-collection chamber.

The inventors have found that agitating the disposable bag dislodges dirt (in particular the fine dust) from the pores of the wall of the bag. The dislodged dirt and dust returns to the interior of the bag and is retained with the other collected dirt and debris where it no longer blocks the pores. The pores (or at least more of the pores) therefore remain available for the subsequent passage or air.

There is also provided a method of operation of a vacuum cleaner having a dirt-collection chamber, a disposable bag in the dirt-collection chamber, and an agitator, the method of operation including actuating the agitator to agitate the disposable bag in the dirt-collection chamber.

Preferably, the agitator is actuated intermittently.

Desirably, the agitator is actuated only when the motor of the vacuum cleaner is switched off, e.g. 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 io 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 from the pores at the same time as the air flow is pushing dirt into the pores.

The inventors have found that after the dirt and dust has been dislodged from the pores at least some of it becomes trapped within the collected dirt and debris in the interior of the bag; subsequent air flow (for example upon the next use of the vacuum cleaner) does not re-activate all of the dirt and dust to re-block the pores.

The agitator is alternatively 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 disposable bag to its maximum level, during which time the agitator can dislodge dirt from the pores of the bag wall. The agitator is preferably switched off before the air flow has reached its maximum level, or at least at the end of a chosen (brief) delay thereafter.

Thus, 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 30 from the pores of the wall of the bag when there is little or no (competing) air flow.

Desirably, the agitator is actuated for a predetermined duration after the motor has been switched off. Preferably the predetermined duration is between around seconds and around 20 seconds, ideally between around 7 seconds and around 15 seconds, and most preferably around 10 seconds.

The chosen delay after which the agitator is actuated (after the motor has been 5 switched off) is preferably less than 3 seconds, ideally less than 2 seconds and most preferably less than 1 second.

Preferably, the agitator oscillates and thereby repeatedly impacts and agitates the wall of the bag. Desirably the frequency of oscillation is between 30 and 100 Hz, to ideally between 50 and 65 Hz, and most preferably around 60 Hz.

Ideally, the agitator is based upon a loudspeaker and comprises one or more permanent magnets and a cooperating electrical coil; electrical current is caused to flow through the coil which causes the coil (and anything connected to the coil) to move relative to the magnetic field. Switching the electrical current on and off, or alternating the current, at a chosen frequency causes the coil to oscillate at that frequency.

Preferably the agitator includes an impacter which is located in the dirt-collection chamber; preferably the impacter is connected directly to an oscillating electrical coil. Desirably the impacter is caused to oscillate with an amplitude of between 1 mm and 3 mm, ideally around 2 mm. Such an amplitude can impart significant impacts to the wall of a disposable bag.

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 disposable bag 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 front view of a vacuum cleaner according to the present invention; Fig.2 shows a sectional view along the line C-C of Fig.1; Fig.3 shows an enlarged view of the part of the vacuum cleaner in the circle F of Fig.2.

DETAILED DESCRIPTION

The vacuum cleaner 10 is of the upright type and has the general structure common to many upright vacuum cleaners. In particular, the vacuum cleaner 10 has a body 12 containing a dirt-collection chamber 14, a motor 16 and an impeller 18. The body 12 is integral with an operating handle 20. A suction head 22 is connected to the body 12 (by way of a steering joint -not seen), the suction head having an opening in its bottom wall at which a rotating brush bar 24 is located. The suction head 22 is connected to the dirt-collection chamber 14 by a flexible hose 26 and an inlet duct 28.

In this embodiment the flexible hose 26 is not extendable but is flexible so as to accommodate the pivoting and rotating movements of the body 12 relative to the suction head 22. Other embodiments of the invention can incorporate an extendable flexible hose which can be released from the suction head to permit additional cleaning operations, in known fashion.

The vacuum cleaner 10 in this embodiment is battery-powered and the batteries 30 are located in the suction head 20. As above stated, the invention could alternatively be used in a mains powered vacuum cleaner. The invention could also alternatively be used in a cylinder vacuum cleaner and in a hand-held vacuum cleaner.

In known fashion, the dirt-collection chamber 14 is adapted to accommodate a disposable bag (not seen). In particular, the inlet duct 28 extends into the top of the dirt-collection chamber and provides a mounting for the mouth of the disposable bag, the mouth providing a substantially air-tight seal to the inlet duct in known fashion. The dirt-collection chamber 14 is of a chosen size and shape to accommodate a suitable disposable bag which (when full) largely fills the dirt-collection chamber 14.

In known fashion, the batteries 30 are connected to the motor 16 which drives the impeller 18 to rotate. This causes air (and entrained dirt and debris) to flow into the opening in the suction head 22, through the suction head, along the hose 26 and inlet duct 28 and into the disposable bag located in the dirt-collection chamber. The air flows through the porous wall of the disposable bag, past the impeller and out of the body 12. A further filter or filters (not seen) are located between the bag and the impeller, and perhaps also downstream of the impeller.

In accordance with the invention, the vacuum cleaner 10 has an agitator 32 which in this embodiment is located near to the top of the dirt-collection chamber 14. The agitator has an impacter 34 which lies inside the dirt-collection chamber, and in use can engage a part of the outer surface of the wall of disposable bag.

In this embodiment the agitator is constructed similarly to a loudspeaker, but with the impacter connected to the electrical coil 36 instead of a diaphragm. Also, the electrical coil and impacter are designed to oscillate at a single chosen frequency (in this embodiment 60 Hz) instead of across a range of frequencies. In common with many loudspeakers, the electrical coil lies close to a set of permanent magnets 40.

The detailed structure of the agitator 32 will not be described since the invention is not limited to any particular structure. Also, a skilled person will readily be able to adapt the relevant parts of a loudspeaker to provide an electrically-powered oscillator and impacter.

Whilst the disposable bag is not shown in Fig.3, it will be understood that the impacter 34 is located to engage the outer surface of the wall of a fitted disposable bag. It will be understood in particular that when air flows through the disposable bag the bag inflates substantially to fill the available volume of the dirt-io collection chamber. A part of the wall of the bag directly engages the impacter as the disposable bag inflates (whether or not dirt and debris fill the bag to the level of the impacter).

When the motor is switched off, for example at the end of a cleaning operation, the motor (and the impeller) gradually slows to a stop, during which time the air flow through the disposable bag decreases and stops. The disposable bag can deflate slightly as the air flow subsides. Nevertheless, it is arranged that the impacter 34 still engages the wall of disposable bag so that when the agitator 32 is actuated after the air flow has stopped (or at least reduced significantly) the impacter repeatedly strikes and shakes the wall of the bag at the chosen frequency to agitate the bag. Some or all of the fine dust and dirt which has become stuck to the inner surface of the wall of the bag, or which has entered into a pore in the wall of the bag, will be dislodged and fall to the bottom of the bag with the other collected dirt and debris.

It has been found that the agitator 32 can agitate all (or a large part) of the bag and dislodge dirt and dust from a large proportion of the wall, notwithstanding that the impacter only engages a part of the wall. Thus, dirt and dust are dislodged from parts of the wall which are not directly engaged by the impacter 34.

At least some of the dirt and dust which is dislodged and which falls to the bottom of the bag will enter into and be retained within the mass of collected dirt and debris within the interior of the bag. When the air flow re-commences (upon the next use of the vacuum cleaner) the retained dirt and dust will not be re-mobilised to re-enter the pores. The agitator can therefore reduce the mass of dirt and dust which is available to block the pores and can thereby reduce the number of pores which are blocked and maintain a greater air flow through the wall of the bag until the bag is full.

It will be understood that maintaining a greater air flow through the wall of the bag until the bag is full has a particular benefit in a vacuum cleaner with an air flow sensor for determining when the bag is full. Minimising the reduction in the air io flow which is caused by the pores of the bag becoming blocked will increase the effectiveness and reliability of the air flow sensor in determining when the bag is actually full.

Claims

CLAIMS1. A vacuum cleaner having a dirt-collection chamber adapted to accommodate a disposable bag, the vacuum cleaner having an agitator configured and positioned to agitate the disposable bag in the dirt-collection chamber.
2. A vacuum cleaner according to claim 1 in which the agitator is actuated intermittently.
3. A vacuum cleaner according to claim 1 or claim 2 in which the vacuum cleaner has a motor and in which agitator is actuated only when the motor of is switched off.
4. A vacuum cleaner according to claim 3 in which the agitator is actuated each time the motor is switched off.
5. A vacuum cleaner according to claim 3 or claim 4 in which the agitator is actuated at the end of a delay after the motor has been switched off.
6. A vacuum cleaner according to claim 5 in which the delay is less than 3 seconds.
7. A vacuum cleaner according to claim 5 in which the delay is less than 2 seconds.
8. A vacuum cleaner according to claim 5 in which the delay is less than 1 second.
9. A vacuum cleaner according to any one of claims 1-9 in which the agitator is actuated for a predetermined duration.
10. A vacuum cleaner according to claim 9 in which the predetermined duration is between around 5 seconds and around 20 seconds.
11. A vacuum cleaner according to claim 9 in which the predetermined duration is between around 7 seconds and around 15 seconds.
12. A vacuum cleaner according to claim 9 in which the predetermined duration is around 10 seconds.
13. A vacuum cleaner according to any one of claims 1-12 in which the agitator oscillates and repeatedly impacts and agitates the wall of the bag.
14 A vacuum cleaner according to claim 13 in which the agitator has a frequency of oscillation between 30 Hz and 100 Hz.
15. A vacuum cleaner according to claim 13 in which the agitator has a frequency of oscillation between 50 Hz and 65 Hz.
16. A vacuum cleaner according to claim 13 in which the agitator has a frequency of oscillation around 60 Hz.
17. A vacuum cleaner according to any one of claims 1-16 in which the agitator comprises one or more permanent magnets and a cooperating electrical coil.
18. A vacuum cleaner according to any one of claims 1-17 in which the agitator includes an impacter which is located in the dirt-collection chamber.
19. A vacuum cleaner according to any one of claims 1-18 in which the agitator has a range of movement of between 1 mm and 3 mm.
20. A vacuum cleaner according to claim 19 in which the agitator has a range of movement of around 2 mm.
21. A vacuum cleaner according to any one of claims 1-20 which is battery powered. 23. 25.A method of operation of a vacuum cleaner having a dirt-collection chamber, a disposable bag in the dirt-collection chamber, and an agitator, the method of operation including actuating the agitator to agitate the disposable bag in the dirt-collection chamber.A method of operation of a vacuum cleaner according to claim 22, the vacuum cleaner having a motor, in which the agitator is actuated each time the motor of is switched off.A method of operation of a vacuum cleaner according to claim 23 in which the agitator is actuated at the end of a delay after the motor has been switched off.A method of operation of a vacuum cleaner according to any one of claims 22-24 in which the agitator has a frequency of oscillation around 60 Hz.