EP0000629B1

EP0000629B1 - Carpet cleaning device

Info

Publication number: EP0000629B1
Application number: EP78300134A
Authority: EP
Inventors: Robert Saul Brown; Robert C. Fay
Original assignee: Milliken Research Corp
Current assignee: Milliken Research Corp
Priority date: 1977-08-02
Filing date: 1978-07-10
Publication date: 1981-11-11
Also published as: CA1121116A; JPS5441560A; AU3826678A; EP0000629A1; DE2861310D1; DK340278A; NO782579L; MX146011A; NZ188020A

Description

This invention relates to a carpet cleaning device according to the introductory part of claim 1.
Carpet cleaning devices with rotating and orbiting brushes are generally known (e.g. GB-PS 945 037).
Recently, a new approach to cleaning carpets has been developed which uses a powdered cleaning composition containing a mixture of extremly porous solid particles and a solvent. This new cleaning composition is described in U. S. Patent Specification 4,013,594 and has proved especially effective in removing dirt from carpets. Only a short interval is required between application and removal of the powdered cleaning composition. It has become possible to clean wall-to-wall carpets in offices and stores during working hours with little disruption of normal affairs.
When the devices which are known in the prior art are used with this powdered cleaning composition, it is found that some areas of the carpet are cleaned much better than other areas and that a streaked appearance results. It is thought that this streaked appearance is due to the fact that the powder, unlike a liquid, must be positively moved into intimate contact with the fibres to be cleaned; therefore, to obtain the full benefit of the powdered cleaning composition, it is thought to be desirable to provide a device which is capable of transmitting a great deal of energy to the carpet in order to bring the powdered cleaning composition into intimate contact with the fibres while distributing this energy uniformly over the area which is scrubbed. Further, it is desirable to provide a device which does not redistribute the powder which has been applied to the carpet as this is also thought to lead to streaking.
It has been proposed to incorporate pressing elements into the brush itself. GB-PS 773 818 suggests that such elements will force the cleaning powder deeply into the pile. US-PS 3 398 422 suggests that such elements create a flicking action which ejects particles from the pile. In contrast to these conflicting suggestions the object of the present invention is to ensure that the powder is effectively pressed into the carpet in such a way that the brush does not redistribute the powder and cause streaking.
The invention accordingly provides the features set forth in the characterising part of claim 1.
Since the presser bar presses the powder into the carpet before the powder is acted upon by the brush, the tendency of the brush to redistribute the powder is reduced.
It is known to use brushes of non-circular shape for various purposes such as better distribution of cleaning liquid (US-PS 2 999 258), intermeshing of brushes (GB-PS 734 834, FR-PS 1 332 090), improved scrubbing action (US-PS 3 290 713). In contrast to this, developments of the present invention are employed to enable the brush itself to assist in pressing the powder into the carpet, namely the developments characterised in claims 2 and 3.
Advantageous shapes of the brush in accordance with claim 3 are characterised in claims 4 to 10.
The invention will be described in more detail, by way of example, with reference to the accompanying drawings in which:-

Figure 1 is a side elevation of a carpet scrubbing machine,
Figure 2 is a schematic sectional view taken along section line 2-2 in Figure 1,
Figure 3 is a sectional view taken along line 3-3 in Figure 2,
Figure 4 is a partly cut-away top view of the carpet scrubbing machine,
Figure 5 is an enlarged schematic side elevation of the front of the machine, partly in section, showing the manner in which powder is dispensed, and pressed into the carpet by a press bar.
Figure 6 is a top schematic view of a rider brush attached the main scrubbing element for pressing powdered cleaning compositions into the carpet,
Figure 7 is a view taken along line 7-7 of Figure 6,
Figure 8 is a top schematic view of a flexible wiper attached to the main scrubbing element for pressing powdered cleaning composition into the carpet,
Figure 9 is a view taken along line 9-9 of Figure 8,
Figure 10 is a partial front elevation, partly cut-away, of the carpet scrubbing machine,
Figure 11 is a schematic bottom view of the preferred brush for use with the machine,
Figure 12 is a view taken along line 12-12 of Figure 11 showing the lie of the bristles, and
Figures 13 to 17 are schematic views of alternative forms of the brush.

As can be seen in Figures 1 and 2 a housing 20 is pivotably mounted on a frame 22. A handle 52 is connected to the frame 22 for pushing the machine across the carpet to be scrubbed. A vacuum cleaner 54 is mounted on handle 52 and is connected to the housing 20 by a flexible hose 56. A powder dispenser of the type described in U.S. Patent Specification 4,019,662 is mounted on the frame 22 and includes a powder storage bin 36 supported by the frame 22 above the housing 20 near the front of the machine, a rotating, reticulated foam cylinder 38 rotatably mounted within the powder storage bin 36 which presses against a foraminous discharge area 40 and a motor 42 for rotating the cylinder 38. A door 44 is provided for closing the foraminous discharge area 40 and serves as a ramp (when it is open as in broken lines in Fig. 5) to aid depositing powder in front of the machine as it moves over the carpet.
Wheels 23 are rotatably mounted at the lower rear of the frame 22 and partially support the weight of the machine in operation. The axis about which both wheels 23 rotate is parallel to the axis about which the housing 20 is free to pivot. This arrangement prevents the housing from canting and ensures that both sides of the machine will be at the same height, thus promoting easier handling of the machine and uniform cleaning across the width of the path covered by the machine. However, since the weight of the device is supported by the wheels 23 and a scrubber brush 32 in the housing and since the housing 20 is free to pivot, carpets having piles of various lengths are automatically accommodated and the housing 20 is free to follow the contour of the carpet. Wheel brushes 62 are mounted on the frame 22 adjacent to the wheels 23 to prevent accumulation of powder on the wheels 23.
As shown in Figure 2, a motor 24 having an output shaft 26 is mounted vertically within the housing 22. An eccentric support plate 27 is keyed on the shaft 26 by a key 29 and also engages the inner race of a bearing 28. Advantageously, as shown in Figures 2 and 3, counterweights 25 may be mounted on the eccentric support plate 27 to compensate for the unbalanced weight of the scrubber brush 32. The outer race of bearing 28 is fixed to a scrubber support member 30 upon which the scrubber brush 32 is mounted. The scrubber brush 32 has tufts 31 of bristles 34 which engage the carpet to be scrubbed and which together with wheels 23 support the weight of the machine.
. An auxiliary motor 42 (Fig. 4) rotates the reticulated foam cylinder 38 within the powder storage bin 36 to cause powder to be dispensed through the foraminous discharge area 40. A bin cover 46 for the top of the storage bin and both the door 44 and the cover 46 provide moisture tight seals which retard the drying out of the powder.
On many carpets, there is a tendency for brushes to redistribute the powder on the carpet. This effect is especially pronounced on low level loop carpets. It is possible to reduce this redistribution by attaching pressing means to the scrubber brush 32 around its periphery. Such pressing means can include pressing members such as riders brushes 37a as shown in Figures 6 and 7 or flexible wipers 37b as shown in Figures 8 and 9.
In the more preferred embodiments, as shown in Figures 10 to 16, tufts 31 of bristles 34 located in protruding areas 33 at the outer periphery of the scrubber brush 32 will function to press the powdered cleaning composition into the pile of the carpet and to minimize redistribution of powdered cleaning composition by the scrubber brush 32.
As shown in Figure 11, the region of the lower face of the preferred brush 32 to which the bristles 34 are applied has several protruding areas 33 around its periphery. Following the periphery of the bristled area from each protrusion 33 in the direction of rotation indicated by the arrow, it can be seen that the distance from the centre of the brush to the outer edge of the bristled area increases steadily until the next protrusion 33 is encountered. As best shown in Figure 12, the bristles are slanted at an angle of about 25° from the vertical but as can be seen in Figure 2 are substantially perpendicular to the radial lines extending from the centre of the brush. The slanted bristles trail as the brush rotates. By applying bristles 34 to the lower face of brush 32 as described, it is possible to minimise the tendency of the brush to redistribute the powder which has previously been laid down on the carpet.
In operation, as the brush 32 orbits and rotates, the tufts 31 in protruding area 33 will encounter particles which have been laid down on the carpet. Since the velocity of the tufts 31 in each of protruding areas 33 which first encounter the particles of cleaning powder is approximately perpendicular to the edge of each bristled area, the tendency of the tufts 31 to ride up over the particles and to press them down into the pile of the carpet is enhanced. In contrast when a circular brush is used, the velocity of the tufts which first encounter the particles of cleaning powder is substantially parallel to the edge of the bristled area. It is thought that this increases the tendency of the bristles to redistribute the powder.
The bristles 34 are inclined for two reasons. First, they facilitate the rotation of the scrubber brush 32 and the proper inclination makes it easier for the protruding areas 33 to ride up over the powder and work them into the carpet. If the motor 24 drives the shaft 26 in the clockwise direction when viewed from the top, the bristles 34 should lean to the left when viewed from the front of the machine. However, if the opposite inclination is used, satisfactory results can be obtained but the device will be more difficult to control.
While the shape shown in Figure 11 is the preferred shape for the bristled area, other shapes such as those shown in Figures 13 to 17 are also quite suitable. Figure 13 shows the shape of the bristled region on a brush having a gear shaped bristled region. Figure 14 shows the shape of the bristled region on a brush having a cross shaped bristled region. Figure 15 shows the shape of the bristled region on a brush having a fan blade shaped bristled region, i.e. radiating whorls of bristles. Figure 16 shows the shape of the bristled region on a brush having a saw blade shaped bristled region. Figure 17 shows the shape of the bristled region on a brush having an oblong shaped bristled region. Figure 16 differs from Figure 11 1 principally in that there are five protrusions in Figure 11 and six protrusions in Figure 16. The shapes shown in Figures 11 and 16 are preferred because of the presence of a plurality of unobstructed tufts 35 located along a radial line at the edges of protrusions 33. Each unobstructed tuft is so located that an imaginary tangential line segment can be constructed which passes through the centre of the tuft and meets the following conditions: the line segment is perpendicular to a radial line drawn through the centre of the scrubber brush to the centre of the tuft; it extends in the direction of rotation of the scrubber brush; it lies within the face of the scrubber brush and it does not pass through any portion of any other tuft or between any two other tufts which are adjacent to each other. Since the brushes shown in Figures 11 and 16 have a plurality of unobstructed bristles lying on a radial line, they are the most preferred embodiment of the invention, but other embodiments in which there are a plurality of unobstructed bristles which do not lie on the same radial line are acceptable. It is thus possible to reduce the tendency of the brush to redistribute powder.
In order to further minimise redistribution of powder, a press bar 48 is pivotably mounted on frame 22 by means of rods 50. As best shown in Figures 4, 5 and 10, each rod 50 terminates in a flattened portion 51 and tabs 49 are attached to each end of press bar 48. Each flattened portion 51 is pivotably connected to the corresponding tab portion 49 and each rod 50 is pivotably connected to the frame 22 so that the press bar 48 is free to follow the contour of the carpet. The storage bin door 44 is of sufficient length to ensure that the powder will be deposited in front of the press bar 48. As the scrubber is advanced over the carpet, powder will be dispensed in front of press bar 48 which minimises redistribution of powder by pressing the powder into the pile of the carpet. The press bar 48 thus tends to immobilise the powder.
Upon energisation of the motor 24, shaft 26 is rotated. Since the shaft 26 is eccentric with respect to the bearing 28, the centre of the scrubber brush 32 is driven in a circle. Since the scrubber brush 32 is free to rotate about its centre, it does not rotate at the same speed as shaft 26 but rotates more slowly. For example, the motor 24 can drive the shaft 26 at 3400 rpm, whereas the scrubber brush 32 will rotate at between 50 and 100 rpm, depending upon the type of bristles used and on the type of carpet being scrubbed.
The particles of cleaning powder dropping from the door 44 are pushed into the pile of the rug by the press bar 48 as the machine is translated over the carpet. The tufts 31 in the protruding areas 33 of the scrubber brush 32 encounter the particles of cleaning powder before the other tufts on scrubber bar 32 and aid in pressing the powder down into the carpet. The remaining tufts 31 scrub the powder into the carpet. The vacuum cleaner 54 prevents excessive dust from escaping from under the housing 20.

Claims

1. A carpet cleaning device which scrubs a cleaning powder into the pile of a carpet by a rotating and orbiting brush, as the device is pushed over the carpet on a wheeled frame, characterised by a powder container (36) arranged to drop cleaning powder on to an area of the carpet ahead of the brush (37), and a transverse presser bar (48) located between the said area and the brush for pressing the powder into the carpet before the powder is acted on by the brush, the presser bar (48) being free to move relative to the frame (22) so as to follow the contour of the carpet.

2. A carpet cleaning device according to claim 1, characterised in that a further pressing element (37a, 37b) is attached to the brush and projects radially from the brush so as further to press the powder into the carpet in advance of the brush, as the further pressing element (37a, 37b) sweeps across the carpet ahead of the brush.

3. A carpet cleaning device according to claim 1, characterised in that the brush (31) has a radially projecting part (33) which sweeps across the carpet in advance of the main part of the brush so as further to press the powder into the carpet.

4. A carpet cleaning device according to claim 3, characterised in that the projecting part (33) of the brush is demarcated on the leading side, with respect to the rotation of the brush, by a radial line.

5. A carpet cleaning device according to claim 3 or 4, characterised in that the outer periphery of the brush has a sawtooth form (Figs 11, 16).

6. A carpet cleaning device according to claim 3, characterised in that the outer periphery of the brush is gear-shaped (Fig 13).

7. A carpet cleaning device according to claim 3, characterised in that the outer periphery of the brush is cross-shaped (Fig 14).

8. A carpet cleaning device according to claim 3, characterised in that the outer periphery of the brush is formed by radiating whorls (Fig 15).

9. A carpet cleaning device according to claim 3, characterised in that the outer periphery of the brush is generally oblong (Fig 17).

10. A carpet cleaning device according to any preceding claim, characterised in that the brush (31) has bristles (34) inclined to trail as the brush rotates.