WO1992004854A1

WO1992004854A1 - Apparatus for cleaning floors, carpets and the like

Info

Publication number: WO1992004854A1
Application number: PCT/GB1991/001643
Authority: WO
Inventors: Michael John Atkinson
Original assignee: Vax Appliances Limited
Priority date: 1990-09-25
Filing date: 1991-09-24
Publication date: 1992-04-02
Also published as: AU8617391A; GB9020850D0

Abstract

To control the flow of cleaning liquid through a liquid delivery pipe to a suction cleaning head, a valve unit (21) is releasably associated with an air flow regulator assembly forming part of the suction line (10). The air flow regulator assembly (11) regulates the flow of air into the suction line through a bleed hole (15) in the absence of the valve. When the valve unit is in place the bleed hole (15) is in communication with a pressure chamber within the valve unit, and a pivoted flap (29) is movable within the pressure chamber towards and away from the bleed opening (15). A piston (25) is coupled to the flat (29) and co-operates with a port (24) in the liquid supply line.

Description

Title: "Apparatus for cleaning floors, carpets and the like"

Description of Invention

This invention relates to apparatus for cleaning floors, carpets and the like by the application and simultaneous removal of an aqueous cleaning agent, and is applicable particularly, but not exclusively, to the type of apparatus described and claimed for example in British Patent No. 1601456 in which a cleaning solution is displaced from a reservoir and through a flexible pipe to a cleaning head in which the solution is delivered through a row of closely spaced fine outlets into a shielded zone inside an inner compartment of the head within a suction chamber whereby the solution is picked up from the carpet or other surface and returned through a suction hose for recovery in a collection vessel.

In such apparatus, the suction head is operative to pick up the solution simultaneously with the delivery thereof to provide a substantially "one-pass" cleaning operation.

Delivery of the cleaning solution to the cleaning head may be effected in various ways, for example, as in the above mentioned patent specification, it may be displaced from the reservoir by the application of slight positive air pressure, derived for example from the exhaust of the suction unit. Alternatively, it may be drawn from the reservoir by the establishment of a reduced pressure zone at the delivery end of the flexible pipe as described and claimed in European patent specification No. 316848. Alternatively, the solution may be delivered by means of a suitable pump.

In all such cases,control of the delivery of cleaning solution is normally achieved by means of a manually operable control usually in the form of a valve which performs a simple on/off function whereby delivery of the solution can be stopped when the apparatus is the solution can be stopped when the apparatus is temporarily out of use, for example while the user pauses to move furniture, or when the apparatus is required to achieve improved drying by the application of suction without simultaneous application of cleaning solution to a previously treated part of the surface being cleaned.

However, the user may overlook the requirement to stop the delivery of solution temporarily, particularly if the cleaning head is briefly left resting on the floor without properly engaging the carpet or other surface, or is temporarily held above the floor. This can give rise to local overwetting in the vicinity of the head. Since this may not be immediately obvious, particularly on a carpet, the user may not then take remedial action to dry up the excess solution, and this in turn may result in damage at the site of overwetting, particularly where the surface is carpeted.

It is accordingly an object of the invention to provide an improved means of controlling the flow of cleaning solution so as to reduce this risk.

According to the invention we provide apparatus for cleaning floors, carpets or the like by the simultaneous application and removal of an aqueous cleaning agent through a cleaning head which affords a liquid delivery outlet and a suction pick-up inlet, wherein a flow control valve is provided in a liquid delivery line leading to said outlet and is operatively coupled to a pressure responsive operating means which is arranged so as to respond to the pressure conditions existing in a suction line connected to said inlet, whereby the flow of liquid in said delivery line is co-ordinated with the establishment of pressure reduction within said suction line.

It will be appreciated that the pressure (usually negative with respect to atmosphere when the apparatus is in use) within the suction line depends on a number of factors including whether the suction unit is operative, or whether the suction head is connected to the suction unit, and if so whether the suction head is effectively engaged with a surface for picking up solution therefrom, and further on the nature of such surface and the extent to which it forms an effective seal with said inlet.

In the simplest case, when the inlet of suction head is not in effective contact with a surface to be cleaned, the air flow through the inlet is not subject to any significant restriction so that there will be little or no pressure drop at the inlet and accordingly the pressure within the suction line will approximate to atmospheric.

However, when the inlet of the cleaning head is to a significant extent closed by application of the head to a surface to be cleaned, the air flow through the head is significantly reduced with the result that an appreciable pressure drop is established within the head and within the suction line.

The difference in pressure which exists between these two conditions is utilised in accordance with the invention at least partially to shut down the delivery of the cleaning solution when the pressure in the suction line approximates to atmospheric, and to allow the cleaning solution to flow through the delivery line at a predetermined rate when the pressure in the suction line is significantly lower than atmospheric.

In this way, removal of the cleaning head from correct face-to-face contact with the surface being cleaned will cause an immediate reduction in, or cessation of, the flow of cleaning solution in the liquid delivery line. Likewise, turning off the suction unit, or disconnecting the suction head from the suction unit, will have a similar effect.

In one arrangement, the flow control valve may have two states, in one of which the flow of liquid is effectively prevented and in the other of which it is permitted. In another arrangement the valve may additionally provide for one or more intermediate states in which relatively reduced flow rates are permitted. In another arrangement the valve may provide for a continuously variable reduction of the liquid flow rate between a predetermined maximum and a minimum, which is preferably zero.

The flow control valve may be formed as detachable unit which is releasably connectable to an air flow regulator provided in the suction line, the air flow regulator affording at least one bleed inlet whereby the pressure within the suction line may be varied by the user at least when the valve is not in place, the bleed inlet or inlets, when the valve is in place, providing communication between the interior of the suction line and a pressure chamber within the valve which houses a movable element forming part of the operating means.

The air flow regulator may comprise a manually movable control member which selectively uncovers a greater area of said bleed inlet or successive separate bleed inlets of greater area, and the control member may afford an abutment which limits movement of said movable element in at least the direction corresponding to increase of flow in said liquid delivery line.

These and other features of the invention will now be described by way of example with reference to the accompanying drawings wherein:-

FIGURE 1 is a diagrammatic cross-section through part of a suction line and a liquid delivery line incorporating a flow control valve in accordance with the invention; and

FIGURE 2 is a transverse section on the line II-II of Figure l. In the embodiment illustrated, the suction line is represented by a rigid tube 10 which also serves as an elongated handle and at its in-use lower end carries an appropriate cleaning head (not shown) which affords a suction chamber communicating with the interior of the tube, and a downwardly presented open mouth which is designed to be engaged in face-to-face relation with a carpet, floor or other surface to be cleaned. At its in- use upper end, the tube 10 will be connected to a flexible suction hose (not shown) which in turn leads to the main body of a suction cleaner which is equipped to separate liquid from the air flow drawn into the cleaner.

The liquid supply line is represented by a flexible pipe which extends alongside the tube 10 and comprising an outlet section 20b connected at its delivery end to a liquid input on the cleaning head (not shown) whereby the liquid is delivered to an inner compartment, for example in the manner illustrated in British Patent specification 1601456 or European patent specification No. 316848 mentioned above. The pipe further comprises an inlet section 20a connected to an appropriate source of cleaning solution for application to the surface to be cleaned.

In accordance with the invention a control valve assembly 21 is formed as a unit which is releasably assembled with a manually operable air flow regulator assembly 11 carried by the tube 10. The assembly 11 is of generally conventional form and comprises a rotatable collar 12 located at one end of a hand grip member 13 and provided with a protruding thumb piece 14 which may conveniently be moved by the operator whilst holding the handle 10 by means of the hand grip member 13.

At a position within the collar 12, the tube 10 is formed with an air bleed opening 15 which is closed by the collar 12 when the thumb piece is in position "0" indicated in Figure 2. Under these circumstances, full suction is applied at the cleaning head. However, where reduced suction is required (assuming that the valve 21 is not in position and the cleaner is in use for dry suction cleaning) the collar 12 may be set to the position illustrated in Figure 2 in which the thumb piece is in position "I". In this position, a first, narrow, opening 16 is in register with the air bleed inlet 15, the area of the opening 16 being less than the area of the inlet 15. In this way, a controlled bleed of air is allowed into the tube 10 so as to reduce the suction available at the cleaning head.

When still further reduction in suction is required the thumb piece 14 is moved to position "II" to bring a second, wide, opening 17 in register with the inlet 15, the opening 17 affording approximately the same area as the inlet 15 so that maximum air bleed is achieved, with consequent minimum suction at the cleaning head.

When the cleaner is to be used for wet process cleaning the valve assembly 21 is connected to the air flow regulator assembly 11. In the illustrated embodiment the hand grip member 13 is formed with an undercut recess 18 at its underside to receive the valve assembly 21 slidably adjacent to the collar 12.

The valve assembly 21 includes an inlet passageway 22 which receives the inlet section 20a of the pipe, and an outlet passageway 23 which receives the outlet section 20b of the pipe. The outlet passageway communicates with the inlet passageway 22 through port 24 and slidably receives a piston 25. A spring 26 biases the piston 25 into a position in which it is disposed between port 24 and the outlet so that flow of fluid through the valve is normally prevented.

The assembly 21 also defines a pressure chamber 28 one side of which is formed by the collar 12, which when the assembly 21 is in use will normally be set to position "I" or position "II" so that opening 16 or 17 provides communication between the interior of the tube 10 and the interior of the pressure chamber 28.

The piston 25 is carried by a piston rod 27 which projects into the pressure chamber 28 in which is disposed a pivotally mounted flap 29 to which the piston rod 27 is coupled.

As can be seen in Figure 1, under the influence of spring 26, the flap 29 is normally held clear of the collar 12 and the opening 16 or 17 therein.

If the pressure within the tube 12 is substantially equal to atmospheric, the flap 29 will remain in the illustrated position and no liquid can be delivered to the cleaning head. These conditions may arise if the suction unit is inoperative, or if the cleaning head is disconnected from the suction unit. They can also arise if the cleaning head is in free space whilst connected to the operating suction unit.

However, when the suction head is placed into face- to-face contact with a surface to be cleaned there is a resulting pressure drop within the cleaning head and within the tube 10. This is communicated to the pressure chamber 28 through the bleed inlet 15 and the opening 16 or 17 aligned therewith. As a result, the flap 29 is drawn towards the bleed inlet 15, thus drawing the piston 25 towards the pressure chamber 28 and thereby at least partially uncovering port 24 so as to allow liquid to flow along pipe sections 20a,20b to the cleaning head whilst it remains in contact with the carpet or other surface being cleaned. If the cleaning head is lifted away from such surface, or if the suction unit is de-energised, or the suction hose is disconnected, the valve will at once return to the condition shown in Figure 1 to cut off further supply of liquid The flap 29 carries an abutment 30 which is arranged to engage the collar 12 at a position spaced from one end of the opening 16 or 17 which is for the time being in register with the bleed inlet 15, and thereby limiting movement of the piston 25 in the flow-permitting direction.

Adjacent to the end of the wide opening 17 the collar may be formed with a recess (indicated at 19) to receive the abutment 30 so that the piston 25 is permitted to move further when the wide opening 17 is in register with the bleed inlet 15 than when the narrow opening 16 is in register therewith.

Thus, the arrangement is such that the port 24 is partially open when the thumb-piece 14 is in position "I" and the narrow opening 16 is in register with the bleed inlet 15, so as to allow a relatively restricted flow of fluid. By contrast, when the thumb-piece 14 is in position "II" and the wide opening 17 is in register with the bleed inlet 15, the piston moves to a position in which the port 24 is fully open, thereby allowing maximum flow of liquid through the assembly 21.

The air flow regulator assembly 11 thus serves its normal purpose of regulating the suction within the cleaning head when the valve assembly 21 is not in position, and serves the further purpose of enabling the user to regulate the maximum liquid flow rate when the valve assembly is attached; whilst the valve assembly itself operates to cut-off the flow when the cleaning head is lifted from the surface being cleaned or when the suction unit is inoperative. Further, by setting the thumb piece 14 in position "0", the user can shut off the liquid at any time.

Whilst, in the embodiment described above, two separate openings 16 and 17 of different dimensions are formed in the collar 12, it would alternatively be possible to form a single opening in the form of a circumferentially extending slot which increases in width from one end to the other so as to provide a continuously variable control, and particularly in that case the collar 12 may carry a circumferentially extending cam face to engage the abutment 30 so as to provide a steplessly variable control of maximum fluid flow rate.

In a simpler embodiment, of course, the collar 12 may be provided with only a single opening corresponding to either opening 16 or opening 17.

Where the invention is to be used with a cleaner having a pumped supply of liquid, the valve assembly 21 may also incorporate a microswitch arranged in such a position as to be operated by the flap 29 in order to shut off, or possibly reverse, the pump when delivery of liquid is not called for.

The assembly of air flow regulator and control valve as illustrated in the accompanying drawings is particularly suitable for use with a dual purpose cleaner of the kind described in British patent specification No. 1601456 which can operate either in a dry suction cleaning mode or in a wet process cleaning mode. However, the invention can also be applied to a cleaner which is designed to operate only in a wet process mode. In that case, the valve assembly need not be detachably associated with the rotatable collar, which would not then function as an air flow regulator controlling the suction within the suction line; instead, the rotatable collar 12 would merely serve to provide for control of the maximum liquid delivery rate or total shut off thereof at the option of the user. However, in a simplified embodiment the rotatable collar 12 could be omitted entirely, so that the valve assembly is at all times operated solely in accordance with the pressure existing within the suction line.

Claims

CLAIMS:-

1. Apparatus for cleaning floors, carpets or the like by the simultaneous application and removal of an aqueous cleaning agent through a cleaning head which affords a liquid delivery outlet and a suction pick-up inlet, wherein a flow control valve is provided in a liquid delivery line leading to said outlet and is operatively coupled to a pressure responsive operating means which is arranged so as to respond to the pressure conditions existing in a suction line connected to said inlet, whereby the flow of liquid in said delivery line is co-ordinated with the establishment of pressure reduction within said suction line.

2. Apparatus according to Claim l wherein the flow control valve has two states, in one of which flow of the liquid is effectively prevented and in the other of which it is permitted.

3. Apparatus according to Claim 2 wherein the flow control valve additionally provides for one or more intermediate states in which relative reduced flow rates are permitted.

4. Apparatus according to Claim 1 wherein a flow control valve provides for a continuously variable reduction of the liquid flow rate between a predetermined maximum and a minimum.

5. Apparatus according to Claim 1 wherein the flow control valve is formed as a detachable unit which is releasably connectable to an air flow regulator provided in. the suction line, the air flow regulator affording at least one bleed inlet whereby the pressure within the suction line may be varied by the user when the flow control valve is not in place, the bleed inlet or inlets, when the valve is in place, providing communication between the interior of the suction line and a pressure chamber within the valve which houses a movable element forming part of the operating means.

6. Apparatus according to Claim 5 wherein the air flow regulator comprises a manually operable control member which selectively uncovers a greater area of said bleed inlet or successive separate bleed inlets of greater area.

7. Apparatus according to Claim 6 wherein the control member affords an abutment which limits movement of said movable element in the direction corresponding to increase of flow in said liquid delivery line.

8. Apparatus according to Claim 7 wherein the manually movable control member is formed with two openings of different cross-sectional area which are selectively registrable with said bleed inlet and adjacent to one of said inlets the_. control member is formed with a recess, a protrusion on the movable element being adapted to engage the control member at a position adjacent to said openings and enter into said recess, thereby establishing two different liquid flow rates.

9. Apparatus according to Claim 8 wherein the movable element comprises a pivotally mounted flap disposed within a pressure chamber which is arranged in communication with said bleed inlet.

10 Apparatus according to Claim 9 wherein the valve comprises a piston which is coupled to said flap and is movable thereby so as to move relative to a port in the liquid delivery line.