The present invention relates to a method and apparatus for cleaning fibrous material having a pile, and in particular for cleaning carpets.

Wet carpet cleaning techniques are known in which water, which may be hot water, together with a cleaning solution is injected into the carpet by means of a pump, and then almost immediately the dirt laden water is extracted by means of a vacuum. Typically the water injection and vacuum nozzles are incorporated in a cleaning head which is used by the operator. Although this method is effective for cleaning most types of soiling, when there is an encrustation caused by beer spillage etc., this must be broken up by means of a powered brush together with various emulsifying chemicals, before the hot water extraction can be effective. Because of the amount of soiling that needs to be carried by the water, a great deal of water is needed and the vacuum often is unable to extract the full amount of dirt laden water, therefore leaving the carpet wet. The known method of cleaning is time

consuming in terms of both the time to carry out the cleaning operation and the subsequent drying time. In addition, problems of shrinkage of the carpet may occur.

Known carpet sweepers and beaters are capable of removing a certain percentage of the loose material from a carpet but are not effective at removing non-loose material of the aforementioned type of dirt encrustation.

My British Patent 2090124 discloses a method of cleaning a cut pile fibrous material, comprising rotating at a speed of at least 1500 rpm, preferably about 3000 rpm, a hub carrying a plurality of individual flexible fingers defining circumferential spaced rows- in which the fingers are spaced apart axially and are relatively thin in relation to their length, the fingers being secured to the hub and extending outwardly therefrom at all times during its rotation, causing the rotating flexible fingers to contact the cut pile fibrous material so that the tips of the fingers impinge on the material and penetrate it to break up and dislodge any foreign matter attached to it. The dislodged matter is removed by suction. This method of cleaning has been found to be much more effective than conventional wet or dry carpet cleaning methods. For convenience the method will be referred to herein as high speed combing.

My British Patent Specification 2122883 concerns a high speed combing apparatus, designed particularly for removing trodden-in chewing gum and similar intractable contaminants, using higher rotation speeds of the cleaning comb, with or without suction to remove the loosened foreign matter.

The high speed combing methods and apparatus described in my prior British Patent Specifications are extremely effective as to removing soiling from carpet, and loft the carpet pile, but comprise a cleaning comb which is. subject to relatively high wear and tear, the fingers of the cleaning comb being subject to becoming dislodged. An object of the present invention is to alleviate the above difficulties by providing an improved from of cleaning comb construction.

According to the present invention there is provided a high speed combing apparatus for cleaning cut pile carpets comprising a cleaning comb having a hub, and a plurality of individual flexible fingers which are spaced apart axially, are relatively thin in relation to their length, and are secured to the hub and extend outwardly therefrom at all times during rotation of the hub, drive means for rotating the hub at a high speed of

at least 1500 rpm, the said hub being contained in a housing having an opening which, in use, adjacent a surface of a cut pile workpiece whereby on rotation of the hub the tips of the fingers flexibly impinge on the work surface and penetrate it to dislodge foreign material therefrom, characterised in that the fingers are arranged in pairs on the hub and each pair comprises a U-shaped length of material looped through a pair of axially adjacent holes in the hub.

The hub preferably comprises a plurality of rings assembled axially together, the rings each being provided with a circumferential array of the pairs of fingers.

According to the present invention there is also provided a high speed combing apparatus for cleaning cut pile carpets comprising a cleaning comb having a hub, a plurality of individual flexible fingers which are spaced apart axially, are relatively thin in relation to their length, and are secured to the hub and extend outwardly therefrom at all times during rotation of the hub, drive means for rotating the hub at a high speed of at least 1500 rpm, the said hub being contained in a housing having an opening which, in use, adjacent a surface of a cut pile workpiece whereby on rotation of

the hub the tips of the fingers flexibly impinge on the work surface and penetrate it to dislodge foreign material therefrom, characteried in that the hub comprises a plurality of rings assembled axially together and each provided with a circumferential array of said fingers.

In a preferred embodiment of the present invention, the fingers may be arcuate and may be of metal or nylon.

Preferably the hub is rotated at a speed of between 1500 rpm and 5000 rpm and more preferably at 3000 rpm.

Conveniently wheels or rollers are carried by the housing to support the apparatus at the correct distance from the work surface. Preferably the ride height is adjustable so as to permit accurate positioning of the flexible fingers relative to the work surface. A handle is provided to facilitate manoeuvring of the apparatus.

In embodiments of the present invention, the hub may incorporate (or the fingers may be composed of) a cleaning agent, and/or the hub may be adapted to apply a cleaning agent to the carpet, as it rotates. Thus, a carpet can be subjected to chemical cleaning at the same time as foreign matter is removed by the high speed

combing, so that a single cleaning operation provides both removal of foreign matter and substantial improvement in appearance. The ability to apply both mechanical and chemical cleaning in a single operation, using a single machine with a single cleaning head, is a very substantial advantage over the application of separate mechanical and chemical cleaning treatments, especially in the domestic market and the equipment hire market.

in one embodiment of this invention, the cleaning agent, with a detergent or solvent action, is incorporated in the fingers of the comb, being released as these impinge on the carpet. The comb fingers are preferably made of nylon or other plastics material. The cleaning agent may be incorporated in the plastics composition of the fingers, or may be dispersed within the plastics material of the fingers for example by micro encapsulation, or the fingers may for example have enclosed or embedded in them longitudinal bodies or stripes of a solid cleaning agent.

A comb incorporating a cleaning agent has very substantial practical advantages, since the entire comb can be supplied as a single unit replacement item, so that the user only has to replace the comb when

necessary and does not have to replenish a supply of cleaning agent in the machine. Combs can be supplied with different types, amounts or concentrations of cleaning agent so that the user can select the comb most

5 appropriate to cleaning a particular carpet or removing a particular type of soiling. For example, combs with an alkaline cleaning chemical can be provided for cleaning carpets of artificial fibres, combs with an acid chemical for cleaning wool carpets; the amount of

10 cleaning chemical released can be varied, depending on the chemical structure of the nylon comb fingers, so that the rate of release of cleaning chemical can be adjusted by changing combs, for example to deal with carpets having a large amount of greasy or oily soiling,

15 a comb with a relatively rapid release of detergent or solvent can be used.

In another embodiment, a cleaning agent, in the form of a liquid or fine powder, is applied from the interior of the comb hub to the carpet, either through hollow

20 fingers, or through holes provided in the hub itself. The cleaning agent may be simply stored in the hub. or may be supplied thereto from a separate reservoir. In the former case, the hub may be refillable with cleaning agent. The cleaning agent is broadcast on to the

25 carpet pile by the centrifugal action arising from the

8 rotation of the hub (which will usually be in the form of a drum). In this embodiment also, pre-packed hub and comb units can be provided as single replacement parts for simplifying selection and replacement by the user, and may incorporate different cleaning agents and/or different rates of release of cleaning agent, to suit different carpet materials and degrees of soiling.

Suction means may be provided for removing the loosened foreign matter from the carpet, for example as described in United Kingdom Patent Specification No. 2090124.

Embodiments of the present invention may incorporate a rotatable cylinder with a sleeve of fibrous material, usually a white fibrous material, for surface cleaning the pile using a wet cleaning agent. This cleaning agent may for example be sprayed onto the carpet, or applied initially to the rotary cleaning sleeve, or may be fed intermittently or continuously to the cleaning sleeve and/or the carpet from a tank provided on the high speed combing machine.

The fibrous cleaning cylinder is mounted so as to be replaceable and is preferably reusable after it has been cleaned.

With such a machine, high speed combing is employed initially to remove the greater proportion of the soiling, and then the machine is used again on the same area with the high speed comb not operating and the wet cleaning cylinder in operation to remove residual oil, grease and general surface staining. A vacuum treatment may be applied simultaneously with or after the high speed combing, to remove the dirt loosened by the high speed combing.

The machine may be constructed so that the same electric motor can drive, selectively, the high speed comb or the wet cleaning cylinder.

The fibrous cleaning sleeve and its rotating supporting cylinder may be supplied as a single replacement unit instead of having a removable sleeve.

In alternative embodiments of the present invention, the apparatus may incorporate a hopper or tank for a cleaning agent in powder form, and means for supplying this cleaning agent to the carpet adjacent to. e.g. immediately in front of. the high speed comb. The vibration caused by rotation of the high speed comb can be used to agitate the powder in the hopper and assist or control the flow of powder on to the carpet.

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The cleaning apparatus described herein can be constructed as a self-contained carpet cleaner, of the upright or cylinder type. Alternatively, the apparatus described herein can be incorporated in a cleaning head designed to be attached to a conventional cylinder vacuum cleaner, in particular, for domestic use. In this case, the attachment head will normally be provided with its own electric power supply and motor to drive its high speed comb and surface wet cleaning cylinder if provided, the cylinder cleaner providing for suction removal of the dislodged soiling matter.

In the accompanying drawings. Figure 1 shows a cleaning comb according to an embodiment of the present invention, and Figures 2 to 5 illustrate high speed combing machines embodying the present invention.

Figure 1 is a cross-section of a cleaning comb according to an embodiment of the present invention, comprising a nylon or other plastics hub or drum 1 with gently curved tines or fingers 2 arranged in pairs, each pair formed by a length of nylon or other material looped through a pair of axially adjacent holes in the hub or drum 1. Preferably, the hub 1 consists of a plurality of separate rings each carrying a single

11 circum erential array of pairs of tines, forming a "spider". The spiders are slotted onto a revolving axle and keyed to rotate with it. As the hub 1 spins the curve in the tines becomes less pronounced but it has been found that the presence of a slight curve in the tine 2 enhances the cleaning effect. The tines can be made of or can incorporate a cleaning agent as described hereinaf er.

The dimensions of the tines are not critical however, in one practical embodiment each tine has a length of about 4 inches on a hub with a diameter of about 1 5/8 inches, and each tine is of circular cross section with a thickness of about 2 mm and a gentle curve in the trailing direction relative to the direction of rotation.

Figure 2 shows a high speed combing apparatus with a ■ housing which includes a downwardly open comb hood 3, carries an electric motor 5. and is mounted on front and rear wheels 23. 25. A hollow cylindrical rotor or hub 4 is mounted to rotate in the comb hood and is driven by the motor through a belt or chain, at a speed of approximately 3000 rpm. The rotor extends across the width of the apparatus, at right angles to the direction of movement defined by the front and rear wheels.

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The rotor carries circumferentially and axially spaced fingers or tines 15 made for example of nylon or other plastics material and stiffly flexible. The hollow interior of each finger communicates with the hollow interior of the hub or rotor 4.

The hub or rotor 1 is filled with a liquid or powder cleaning agent and may be refillable or a sealed unit.

A front vacuum pipe 26 is connected to a lateral vacuum bar 28 mounted at the front of the comb hood. A rear vacuum pipe 27 is connected to a suction opening 24 in the rear of the comb hood adjacent to a scoop 29 which extends downwards so that its leading edge is close to the surface of the carpet being cleaned. The vacuum pipes are connected to a separate vacuum unit for example a vacuum cylinder, or to a vacuum unit mounted on the high speed combing apparatus itself.

The handle is pivotable on the housing and is provided with a height adjusting strut 22 and with a control unit 21 for controlling the functions of the apparatus.

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The hub 1 and comb fingers 2 are designed so that the contained cleaning agent is expelled through the fingers on to the carpet being cleaned, only when the hub 1 is rotated at a high speed.

The individual fingers 2 are arranged in circum¬ ferential spaced rows in which the fingers are spaced apart axially, and the fingers are relatively thin in relation to their length. They extend outwards from the hub 1 or rotor at all times so that on rotation, the tips of the fingers impinge flexibly on the carpet surface and penetrate it to dislodge foreign material from it. The required depth of penetration can be set by means of the height adjustment on the apparatus to take account of variations in the pile thickness and wear of the fingers. The high speed impact of the finger tips on the carpet performs a vigorous combing action. At the same time, centrifugal effects expel the cleaning agent through the fingers into contact with the carpet in order to release stubbon soiling such as sticky or oily material. Material dislodged from the carpet pile is removed by suction through the vacuum pipes 26 and 27.

The described machine can provide, in a single operation, very effective removal of both particulate

14 material and surface contamination from a carpet, leaving the carpet clean, with its pile lofted and its surface appearance substantially improved.

As explained previously, the hollow rotor or hub may be supplied with liquid or powder cleaning agent from a reservoir mounted on the cleaning apparatus, instead of being filled with the cleaning agent.

Alternatively or in addition, a liquid or other cleaning agent can be applied to the carpet through a spray bar 31 connected to a tank 32 mounted on the apparatus as shown in Figure 4. In this case the rotor and comb tines may be designed to dispense a cleaning agent as described above, or may be designed simply to comb the carpet pile without dispensing a cleaning agent. Suitable positions for the spray bar 31 include: just inside the front of the comb hood; at the rear of the comb hood below the rear suction scoop or intake; adjoining the rear wheels.

Figure 3 shows a high speed combing machine generally as shown in Figure 2, but additionall provided with a surface cleaning roller 30 for surface cleaning the pile using a wet cleaning agent sprayed onto the carpet (for example by a spray bar as described

15 above), applied initially to the cleaning roller 30. or fed intermittently or continuously to the cleaning roller and/or the carpet from a tank provided on the high speed combing apparatus or separately. As explained above, such a machine is used first as a high speed combing machine, and then it is passed over the same area with the cleaning roller 30 operating to remove surface stains. The cleaning roller of course is rotated at a much lower speed than the high speed combing rotor.

Figure 3 shows alternative mounting positions for the cleaning roller 30 namely ahead of the comb hood, behind the comb hood, or at the rear of the machine.

Figure 5 shows a further embodiment of the high speed combing machine according to the invention. This machine is constructed generally as shown in Figure 2. but is additionally provided with a hopper 33 which in use contains a cleaning agent in powder form. This hopper is connected by a duct 34 to a distributor 35 which has one or more outlets just above the carpet, immediately in front of the high speed comb or rotor 4. Conventional control devices may be provided for controlling the flow of cleaning powder. The vibration of the machine in operation agitates the powder in the hopper and facilitates its flow through the duct and distributor.