This application is a national stage application under 35 USC 371 of International Application No. PCT/GB2005/003722, filed Sep. 28, 2005, which claims the priority of United Kingdom Application No. 0422907.6, filed Oct. 15, 2004, the contents of both of which prior applications are incorporated herein by reference.
This invention relates to a vacuum cleaning head which can be used with, or form part of, a vacuum cleaner.
Vacuum cleaners are generally supplied with a range of tools for dealing with specific types of cleaning. The tools include a floor tool for general on-the-floor cleaning. It is well-known to provide a floor tool in which a brush bar is rotatably mounted within a suction opening on the underside of the tool, with the brush bar being driven by an air turbine. The brush bar serves to agitate the floor surface beneath the tool so as to release dirt, dust, hair, fluff and other debris from the floor surface where it can then be carried by the flow of air to the vacuum cleaner itself. The turbine can be driven solely by ‘dirty’ air which enters the tool via the suction opening, it can be driven solely by ‘clean’ air which enters the tool via a dedicated inlet which is separate from the main suction opening, or it can be driven by a combination of dirty and clean air.
In a turbine driven tool which has a dedicated clean air inlet to drive the turbine which is separate from the main, floor engaging inlet, there can be a difficulty in driving the turbine at a sufficient speed. When viewed in terms of the amount of resistance experienced by the airflow, the path through the main inlet offers a lower resistance than the path through the turbine inlet. Thus, the airflow will tend to take the lower resistance path through the main inlet.
Accordingly, the invention provides a vacuum cleaning head comprising a housing having an agitator rotatably arranged in a chamber, the chamber having an air inlet and an air outlet, the housing further comprising an air turbine for driving the agitator and an air inlet in the housing for admitting air to drive the turbine, wherein a restrictor is arranged in the outlet of the chamber so as to restrict the outlet when the head is pressed against a surface to be cleaned.
The provision of a restrictor that restricts the chamber outlet when the tool is pressed against a surface permits a greater flow of air through the inlet associated with the turbine when the tool is being used in a cleaning operation. Thus the turbine, and hence the agitator, is driven at a higher rotational speed than was achievable hitherto, for efficient cleaning.
Advantageously, the restrictor moves against the force of resilient means so that, when the head is removed from the surface, the restrictor moves back to its previous position and restricts the outlet to a lesser extent, if at all. Thus, less air flows through the turbine so that it runs at a reduced speed. This helps prolong the life of the turbine, the agitator and the device that transmits torque between the turbine and the agitator, for example a pulley.
Preferably, the restrictor is associated with, and may be an integral part of, a sole plate, which may be pivotably mounted in the housing.
A catch may also be provided to release the sole plate and thus render accessible the chamber so that blockages may be removed by the user.
The agitator, which may be a brush bar, may itself be removable for replacement or repair.
In each aspect of the invention, the vacuum cleaning head can be a tool which attaches to the end of a wand or hose of a cylinder (canister, barrel) or upright vacuum cleaner, or it can form part of a vacuum cleaner itself, such as the cleaning head of an upright vacuum cleaner.
The invention will now be described, by way of example, with reference to the accompanying drawings, in which:—
a is a partly-sectional side view of the cleaner head of
b is a view from behind of the cleaner head of
a is a partly-sectional side view of the cleaner head of
b is a view from behind of the cleaner head of
Like reference numerals refer to like parts throughout the specification.
The tool 1 further comprises an air turbine 7, which is arranged to drive the brush bar 4. The air turbine 7 includes an impeller (indicated schematically by the numeral 8 in
A driving mechanism connects the turbine 7 and the brush bar 4 and serves to transmit torque from the turbine to the brush bar. The driving mechanism typically comprises a pulley arrangement (not shown), which is driven by the output shaft of the turbine 7. A casing 11 surrounds the pulley system in order to protect it.
In use, the suction force created by suction fan 16 draws air into the tool 1 via the main suction inlet 6 on the underside of the tool and through the turbine air inlet 9. Air flowing through inlet 9 is used to drive the turbine 7 before flowing towards the main body 15 of the vacuum cleaner 12. Dirty air which is drawn through the main suction inlet 6 does not pass through the turbine 7 at all. In this way, the turbine 7 does not become fouled with dirt and debris from the dirty airflow.
A suction release trigger 21 is provided on a handle of the wand 13. The suction release trigger 21 is a valve that can be operated by a user to admit air into the wand 13 and to reduce the level of suction at the tool 1. Normally, a user will operate this valve when the suction airflow draws an item, such as a lightweight rug, against the inlet 6, so that the item becomes stuck to the tool 1. Air is admitted into the airflow path via the suction release trigger 21, suction at the inlet 6 is reduced and the object which has been ‘stuck’ to the tool is released.
a is a partly sectional side view of the tool 1. The sole plate 5 is pivotably mounted in the chamber 3 and, in this position, extends below the lower surface of the housing 2 of the tool 1. In this drawing, the outlet 22 of the chamber is also visible. The outlet 22 of the chamber 3 communicates with the outlet 10 of the tool 1. The pivot 23 for the sole plate 5 is provided at the front of the tool, close to the front wall of the housing 2. The inner surface of the front wall is provided with resilient means in the form of a metal tab 24, which abuts the front upper surface of the sole plate 5, adjacent the pivot 23. Another pivot and metal tab may be provided on the other side of the tool 1. The tool 1 also includes a restrictor in the form of restricting member 25 arranged adjacent the outlet 22 of the chamber. In this embodiment, the restricting member 25 is an integral part of the pivotable sole plate 5.
The tool 1 is shown from behind in
One of the problems with a turbine-driven tool which has a dedicated inlet for air to drive the turbine is that too great a proportion of the incoming air can flow into the tool via the main suction inlet 6 rather than through the turbine 7. When viewed in terms of the amount of resistance experienced by the airflow, the path through the main inlet 6 offers a lower resistance than the path through the turbine inlet 9.
In accordance with the invention, the tool 1 is arranged so that, when it is pressed against a surface to be cleaned, the sole plate 5 pivots towards the housing 2 and the restricting member 25 extends further into the outlet 22 of the chamber 3, thereby restricting the outlet by reducing its effective cross-sectional area. The restricting member 25 serves to restrict the flow of air from the brush bar chamber 3. The restricting member 25 is designed to distribute incoming air between the main inlet 6 and the turbine inlet 9 in a satisfactory ratio. Thus, a higher proportion of the suction airflow through the tool travels via the turbine 7, causing the impeller 8 to spin faster. Consequently, the brush bar is driven at a higher rotational speed, sufficient for effective cleaning.
The tool 1 is shown in
When the sole plate 5 pivots upwardly into the housing 2, the front upper edge of the sole plate is urged against the or each resilient metal tab 24, thereby deforming it. When the user has finished cleaning a surface with the tool 1, the user lifts the tool from the surface and the resilient metal tabs 24 urge the sole plate 5 back into the position shown in
The tool 1 also includes a catch 26 arranged to engage a protruding portion 27 extending from the sole plate 5 remote from the pivot 23 in the housing 2. The catch 26 is slidably releasable in order to release the protruding portion 27 of the sole plate 5. Thus, the sole plate 5 may be pivotably moved outwardly, away from the chamber 3, in order to make the chamber accessible. This may be to allow the user to clear blockages in the chamber, to remove fibers entangled in the bristles of the brush bar 4, or to allow the user to replace the brush bar 4. The brush bar 4 may be pivotably releasable through the suction opening, such as is described in our co-pending patent application GB0410699.3. Visual indicia, in the form of an arrow 28 for example, may be provided on the catch 26, in order to assist the user in releasing the catch correctly. When the user wishes to replace the sole plate 5, the user simply pivots the sole plate back towards the housing 2. The protruding portion 27 of the sole plate 5 is urged against a bevelled edge 29 on the catch 26, thereby causing the catch to slide away from the protruding portion of the sole plate. Resilient means (not shown) in the catch 26 serve to return the catch to its normal position once it has re-engaged the sole plate 5.
The invention provides a turbine-driven tool in which the agitator is driven at increased speed when the tool is employed and yet is able to power-down when not being actively used. Thus, the agitator is able to increase the effectiveness of a cleaning operation. Wear and tear to the component parts is reduced by causing them to rotate at reduced speed when not in active use.
An alternative tool is shown in
In this embodiment, the restrictor is in the form of a wedge 30, the thin end portion of which is pivotably mounted in the lower surface 31 of the floor tool. The wedge 30 occupies a rear portion of the tool and, in the position shown in solid lines in
Another alternative restricting member is illustrated in
A further alternative embodiment is shown in
Further variations will be apparent to the person skilled in the art. For example, with reference to the first embodiment of the invention, although it is convenient to form the restricting member and the sole plate as one piece, they may be formed separately. The restricting member and the sole plate may be urged against respective resilient means.
The restricting member need not extend across the full width of the outlet to the chamber. Alternatively, or additionally, the restricting member may be profiled so as to present an optimum restriction in the cross-section of the outlet, or differing restrictions to the outlet in dependence on the extent to which the tool is pushed against a surface to be cleaned.
The resilient means need not comprise deformable metal tabs. Helical springs, foam wedges or other suitable resilient mechanisms may be employed.
The invention has been described with reference to a tool having a brush bar but is equally suitable in connection with other forms of agitator, such as a beater. The agitator need not be driven by a pulley system; a system of gears, for example, may be employed to transmit torque from the turbine to the agitator.
Number | Date | Country | Kind |
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0422907.6 | Oct 2004 | GB | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/GB2005/003722 | 9/28/2005 | WO | 00 | 3/30/2007 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2006/040509 | 4/20/2006 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
5416948 | Worwag | May 1995 | A |
5950275 | Wörwag | Sep 1999 | A |
20020108210 | Kaffenberger | Aug 2002 | A1 |
Number | Date | Country |
---|---|---|
3308294 | Sep 1984 | DE |
42 29 030 | Mar 1994 | DE |
0 564 222 | Oct 1993 | EP |
0963 731 | Dec 1999 | EP |
2 393 383 | Mar 2004 | GB |
11009523 | Jan 1999 | JP |
WO-2004028330 | Apr 2004 | WO |
Number | Date | Country | |
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20070256273 A1 | Nov 2007 | US |