EP1661502B1

EP1661502B1 - Telescopic wand for vacuum cleaner

Info

Publication number: EP1661502B1
Application number: EP20050257082
Authority: EP
Inventors: Alexander Anthony Denny Bassett
Original assignee: Hoover Ltd
Current assignee: Hoover Ltd
Priority date: 2004-11-22
Filing date: 2005-11-17
Publication date: 2012-09-12
Anticipated expiration: 2025-11-17
Also published as: EP1661502A2; CN1781438B; CN1781438A; EP1661502A3; GB0425626D0

Description

This invention relates to a wand for a vacuum cleaner and to a method of using a vacuum cleaner provided with such a wand.
Vacuum cleaners of the so-called cylinder or canister type are well known. Such cleaners comprise a body incorporating a motor-and-fan unit and a filter bag or cyclone for the separation and collection of dirt. In use, dust laden air is drawn into the vacuum cleaner body by the motor/fan unit along a tubular wand which is connected to the vacuum cleaner body via a flexible hose. A floor-engaging cleaning tool is connected to the distal end of the wand remote from the flexible hose. The end of the wand remote from the cleaning tool is equipped with a handle which the user grips in order to repeatedly move the wand and its associated cleaning tool to and fro over the surface being cleaned.
In use, the wand should be inclined to the surface being cleaned at an angle of typically 30 to 45 degrees, so that the cleaning tool adopts the correct attitude on the floor. However, the angle at which the wand is held is dependant on the height and the preferred posture of the user. Many wands are of a fixed length or of a length which can only be adjusted by the addition or removal of elongate extension tubes. Accordingly, there is a risk that the wand may not be inclined to the surface being cleaned at the correct angle, or that users may tire trying to hold the wand at an angle which does not suit their height or preferred posture.
In order to overcome this problem, it has been proposed to provide a wand which includes a tube assembly comprising a pair of rigid tubes telescopically coupled to each other and provided with a locking mechanism which includes a catch on one of the tubes for selectively engaging any one of a series of transverse grooves formed longitudinally on the other tube, so that the tubes can be locked to each other at selected positions of longitudinal extension. One such assembly is disclosed in European Patent EP0293518 .
In use, the user can actuate the locking mechanism to set the most comfortable wand extension to suit his or her height or preferred posture. The extension of the wand can also be adjusted to assist in cleaning under tables and other items of furniture.
A problem of such telescopic wands is that the user may have to use both hands to adjust the length of the wand. In particular it is difficult for the user to adjust the overall length of the wand whilst cleaning. Furthermore, it is not possible to effect a precise adjustment of the length of the wand due to the minimum intervals of the locking grooves carried on one of the tubes.
A solution to this problem is provided by the telescopic wand disclosed in International Patent Application WO01/65992 , in which a longitudinally extending rack is disposed on the lower tube and a motorised worm gear on the upper tube. A switch is provided on the handle portion of the wand for actuating the motor to adjust the extension of the wand, without the need for the user to grasp the tubes. The extension can be set at any position between the fully extended and fully retracted positions. The extension can also be adjusted whilst cleaning, for example so that the wand can reach under furniture more easily.
A disadvantage of known wands is that the repeated to and fro cleaning movement is tiring, particularly for users of slight build, or during cleaning of surfaces of extensive area. In addition, difficulty can be experienced in moving the cleaning tool to some areas of the surface being cleaned.
In accordance with the present invention, there is provided a wand for a vacuum cleaner as defined in claim 1. Also in accordance with the present invention, there is provided a method of cleaning a surface as defined in claim 12.
In use, during forward and rearward movement, the cleaning tool is able to move a greater distance over the surface being cleaned than the distance through which the user's hand moves the wand. In this manner, the cleaning operation is less tiresome for the user.
During forward movement, the cleaning tool is able to extend into areas of the surface being cleaned which would otherwise be difficult to reach.
Preferably, the forward and rearward movement is successively repeated so as to progressively move the floor-engaging cleaning tool over the entire surface to be cleaned.
The telescopic wand disclosed in International Patent Application WO01/65992 is unsuitable for use in accordance with the method of the present invention because the pitch of the teeth on the rack needs to be small to give the required finite control and to prevent the motor from jamming. Accordingly, the time taken for the worm gear to travel along the length of a rack of suitable length for the present invention would far exceed the time taken for the user to urge the wand forwardly or rearwardly.
Another disadvantage is that the provision of a sufficiently powerful motor is expensive and cable is required to feed power to the motor on the wand. This cable can easily be damaged and hence needs to carry a low voltage to prevent harm to the user. A low voltage is only able to deliver a relatively low power without excessive current and hence the motor will not have adequate power to extend and retract the tubes in a quick and efficient manner. Furthermore, the use of a low voltage cable requires the provision of a power supply, which can be expensive.
In the wand of the present invention, preferably the drive means is arranged to apply a force to cause relative movement of the first and second tubes in one direction against a bias acting, upon cessation of the applied force, to cause relative movement of the first and second tubes in the opposite direction. Preferably the force applied by the drive means serves to cause the first and second tubes to retract against the bias, the bias then acting, upon cessation of the force, to extend the tubes. Alternatively, the force applied by the drive means may cause the tubes to extend against the bias, the bias then acting, upon cessation of the force, to retract the tubes. Instead the drive means may be arranged to apply a first force to cause relative retraction of the tubes and a second force to cause extension of the tubes.
Preferably an operator for the drive means is disposed on the handle and arranged to be gripped by the user so as to be displaced in one direction, relative to the handle, as the cleaning tool is urged forwardly, and in the opposite direction as the cleaning tool is urged rearwardly. Preferably the operator comprises a sleeve slidably mounted on the handle for displacement along a line which extends at 30 to 45° to the longitudinal axis of the tube assembly: in use, therefore, the operator is displaceable along a line generally parallel to the surface being cleaned.
Preferably the drive means comprises a pneumatic actuator arranged to be actuated by air pressure derived from the vacuum cleaner with which the wand is used. This air pressure may be derived from the upstream side and/or downstream side of the motor/fan unit of the vacuum cleaner. Conveniently, the pneumatic actuator may be arranged to be actuated by the negative air pressure present, in use, in the longitudinal airflow duct within the wand.
Also in accordance with the present invention, there is provided a wand for a vacuum cleaner, the wand comprising a handle and an elongate tube assembly extending from said handle, said tube assembly comprising first and second elongate tubes which are telescopically interconnected, and drive means connected between said tubes for varying the extension thereof, said drive means comprising a pneumatic actuator arranged to be actuated by air pressure derived from the vacuum cleaner.
An embodiment of this invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Figure 1 is a side view of a conventional canister vacuum cleaner;
Figure 2 is a schematic side view of a vacuum cleaner wand in accordance with the invention;
Figure 3 is a schematic sectional view through a control valve of the wand of Figure 2, the valve being shown in a configuration in which the wand is contracted; and
Figure 4 is a schematic sectional view through the control valve of Figure 3, the valve being shown in a configuration in which the wand is expanded.

Referring to Figure 1 of the drawings, a conventional canister vacuum cleaner comprises a body 10 housing a motor/fan unit 11 and a dust separator 12. A wand 13 is connected to the body 10 by an elongate flexible hose 14. In use, the dust separator 12 serves to separate dirt and dust from an airstream which is drawn along the wand 13 and into the body 10 by the motor/fan unit 11.
The wand 13 comprises a tubular handle 15 of moulded plastics and an elongate metal tube 16 extending from the handle. The outer end of the tube 16 is connected to a floor cleaning head 18 via an extension tube 17, which can be removed to shorten the wand for compact storage. Alternatively, the tubes 16,17 may be telescopically interconnected and provided with latching means to permit the wand to be set to a length suitable for the cleaning task in hand.
In use, the handle 15 is grasped by the operator and used to propel the cleaning tool 18 over the surface to be cleaned, usually with a reciprocating to and fro movement.
Referring to Figure 2 of the drawings, there is shown a wand in accordance with this invention, in which like parts with the wand of Figure 1 are given like reference numerals. The lower tube 17 has its upper end sealingly and telescopically mounted inside the lower end of the upper tube 16 for movement between fully extended and fully retracted positions. A pneumatic actuator 19 is disposed on the exterior of the wand and comprises a cylinder 20 mounted at its upper end to the upper tube 16 and a ram or piston 21 slidingly mounted inside the cylinder 20 and fixed at its lower end to the lower tube 17. A compression spring 22 is also disposed on the exterior of the wand and is connected at its upper and lower ends respectively to the upper and lower tubes 16,17.
The interior of the cylinder 20 is connected by a flexible duct 24 to a valve assembly 23 disposed on a rearward portion 26 of the handle 15 which extends at 30 to 45 degrees to the longitudinal axis of the tubes 16,17 in a direction which, in use, extends substantially horizontal to the surface being cleaned, as shown.
Referring to Figures 3 and 4 of the drawings, the valve assembly 23 comprises a sleeve 25 which is slidably mounted on the portion 26 of the handle 15 for movement between a rearward position (Figure 3) and a forward position (Figure 4). The forward and rearward movements of the sleeve 25 are limited by respective annular stop elements 28,29 disposed at spaced apart positions on the portion 26 of the handle 15.
A passage 27 extends radially through the wall of the sleeve 25 adjacent its distal end. The outer end of the passage 27 is connected to the duct 24 which extends from the pneumatic actuator 19. The inner end of the passage 27 is arranged to register with an aperture 30 formed in the wall of the portion 26 of the handle 15 when the sleeve 25 is in its rearward position (Figure 3). An internal bore 31 extends axially through the wall of the sleeve 25 from its proximal end, the opposite end of the bore 31 connecting with the passage 27.
In use, with the wand initially fully extended as shown in Figure 2, the user holds the wand by grasping the sleeve 25 of the valve 23 and energises the vacuum cleaner to cause an airflow F through the wand. When the wand is urged rearwardly in direction A, the sleeve 25 slides rearwardly to the position of Figure 3, thereby causing the inner end of the passage 27 in the sleeve to register with the aperture 30 in the wall of the portion 26 of the handle 15 and connecting the sub-atmospheric pressure inside the wand to the interior of the pneumatic cylinder 20 via the duct 24. In its rearward position, the proximal end of sleeve 25 seals against the rear stop element 29 to close the duct 31 and to prevent any loss of suction in the passage 27.
The reduced pressure inside the cylinder 20 draws the ram 21 of the pneumatic actuator 19 inwardly against the bias of the spring 22 to pull the lower tube 17 into the upper tube 16, thereby shortening the wand.
When the user, still gripping the sleeve 25, urges the wand forwardly in direction B, the sleeve 25 slides forwardly to the position of Figure 4, thereby causing the inner end of the passage 27 in the sleeve 25 to move out of register with the aperture 30 in the wall of the portion 26 of the handle 15 and isolating the sub-atmospheric pressure inside the wand from the interior of the pneumatic cylinder 20. In its forward position, the proximal end of sleeve 25 is disposed away from the rear stop element 29 to open the duct 31, thus allowing the interior of the pneumatic cylinder 20 to vent to atmosphere and allowing the spring 22 to push the lower tube 17 out of the upper tube 16, thereby extending the wand.
The effect of the foregoing movements is that, during cleaning, the wand is extended as it is urged forwardly and retracted as it is urged rearwardly. Accordingly, the stroke length of the reciprocating movement of the floor-engaging cleaning head 18 is considerably greater than that resulting from the user's hand movements alone. In this manner, the user is able clean a greater area during each stroke, with the result that the cleaning operation is less tiresome.
It will be appreciated that in a practical implementation of the arrangement described in the foregoing, the pneumatic cylinder 20 and the compression spring 22 would preferably be integrated into the tubular wand construction rather than forming separate components mounted on the exterior of the telescopic suction tube. It is envisaged that the pneumatic cylinder 20 and the compression spring 22 could be mounted concentrically with the tubes 16, 17.
Preferably the wand includes means for locking the tubes 16, 17 in one or more selected positions between their fully extended and contracted positions: the user can then use the wand in conventional manner, with the wand locked in a desired extension.

Claims

A wand for a vacuum cleaner, the wand (13) comprising a handle (15) and an elongate tube assembly (16) extending from said handle and arranged for a cleaning tool (18) to be disposed on its distal end, said tube assembly comprising first and second elongate tubes (20,21) which are telescopically interconnected, and drive means (19) connected between said tubes for varying the extension thereof, characterised by said drive means being activated to increase the extension of said tubes in response to said cleaning tool being urged during use forwardly over a surface to be cleaned, and to decrease the extension of said tubes in response to said cleaning tool being urged during use rearwardly over said surface to be cleaned.
A wand as claimed in claim 1, in which said drive means is arranged to apply a force to cause relative movement of said first and second tubes in one direction against a bias, said bias acting, upon cessation of said force, to cause relative movement of said first and second tubes in the opposite direction.
A wand is claimed in claim 2, in which said drive means is arranged to apply said force to cause said tubes to retract against said bias, said bias acting, upon cessation of said force, to extend said tubes.
A wand is claimed in claim 2, in which said drive means is arranged to apply said force to cause said tubes to extend against said bias, said bias acting, upon cessation of said force, to retract said tubes.
A wand is claimed in claim 1, in which said drive is arranged to apply a first force to cause relative movement of said tubes in one direction and a second force to cause relative movement of said tubes in the opposite direction.
A wand as claimed in any preceding claim, in which an operator for said drive means is disposed on said handle and arranged to be gripped by the user so as to be displaced in one direction, relative to said handle, as said cleaning tool is urged forwardly, and in the opposite direction as said cleaning tool is urged rearwardly.
A wand as claimed in claim 6, in which said operator is slidably mounted on said handle.
A wand as claimed in claim 7, in which said operator is slidably mounted on a said handle for displacement along a line which extends at 30 to 45° to the longitudinal axis of said tube assembly.
A wand as claimed in any preceding claim, in which said drive means comprises a pneumatic actuator arranged to be actuated by air pressure derived from the vacuum cleaner.
A wand as claimed in claim 9, in which said pneumatic actuator is arranged to be actuated by air pressure desired from the upstream side and/or downstream side of the motor/fan unit of the vacuum cleaner.
A wand as claimed in claim 10, in which said pneumatic actuator is arranged to be actuated by negative air pressure derived from the longitudinalairflow duct within said wand.
A method of cleaning a surface, the method comprising the steps of:
providing a vacuum cleaner which comprises a wand having a handle, en elongate tube assembly extending from said handle and a cleaning tool disposed on the distal end of the said tube assembly, said tube assembly comprising first and second elongate tubes which are telescopically interconnected, and drive means connected between said tubes for varying the extension thereof;

engaging said cleaning tool with the surface to be cleaned and urging said cleaning tool forwardly over the surface to be cleaned thereby causing said drive means to increase the extension of said tubes; and

urging said cleaning tool rearwardly over the surface to be cleaned thereby causing said drive means to decrease the extension of said tubes.
A method as claimed in claim 12, in which the forward and rearward movements of the cleaning tool are successively repeated.
A method as claimed in claim 12 or 13, in which the user grips said handle via an operator for said drive means, said operator being mounted on said handle for displacement in one direction relative thereto as the user urges the cleaning head forwardly, and for displacement in the opposite direction as the user urges the cleaning head rearwardly.