BACKGROUND

The present invention relates to a cleaning head to be connected to a vacuum cleaning appliance, such as for example a vacuum cleaner, an electric broom, a can vacuum cleaner, a bagless cordless stick vacuum cleaner or a robot vacuum cleaner, to suck up dust and/or fluids and/or debris from a surface.

In particular, the present invention relates to a cleaning head which provides improved handling, while maintaining a high suction efficiency. Even more particularly, the present invention provides a solution to reduce the so-called pushing force, i.e. the force required to push the cleaning head forward or backward.

STATE OF THE ART

As is known, a vacuum cleaner, an electric broom or a similar vacuum cleaning appliance includes a cleaning head for sucking up dust, debris or fluids from a surface. In the field of household appliances, a cleaning head is generally defined with the term "brush". For the purpose of this description, therefore, the terms “cleaning head”, "suction head" and "brush" are considered equivalent. Still for the purpose of the present invention, the term "vacuum cleaner" will be used with a broad meaning to include all appliances, for professional or domestic use, for cleaning by suction. Therefore, the term "vacuum cleaner" will include a vacuum cleaner, a trailed vacuum cleaner, an electric broom, a so-called bin vacuum cleaner, a bagless cordless stick vacuum cleaner, a robot vacuum cleaner, a centralized suction system for domestic or industrial use and a combined suction and steam/detergent delivery device.

Basically, a known cleaning head comprises a base plate shaped in such a way as to present at least one base plate channel open towards a surface to be sucked, a suction duct (or even just "duct") which, in use, is integral with the base plate and in fluid communication with the base plate channel and possibly a cover body which can be coupled to the base plate - suction channel assembly. The other end of the suction duct communicates with a suction pipe, usually through a rotatable joint. Cleaning heads are also known in which the suction duct, in use, is integral with the cover body.

In this description and in the claims, the expression "suction efficiency" will substantially mean the ratio, in percentage, between the sucked material and the material to be sucked. The aspiration tests are carried out following the indications of the EN 60312-1 : 201 /standard.

Although various cleaning heads are available on the market which perform the function of sucking dust and/or fluids and/or debris from a surface in a sufficiently efficient way, the Applicant has felt the need to improve the performance of known cleaning heads. In particular, the Applicant has felt the need to increase handling, maintaining a high efficiency of suction of dust or debris from a surface.

In fact, to increase suction performance, manufacturers tend to design the base plate and the base plate channel so that there is high adhesion and that most of the suction air is not wasted. Basically, the manufacturers mainly aim to improve suction but, on the other hand, the brush is "sealed" to the surface to be vacuumed, and difficult to move forward or backward in normal use. The pushing force is therefore high and the effort on the part of the user is correspondingly high.

DE 10 2018 107424 A1 discloses a vacuum cleaner floor nozzle attachment for reducing the pushing force of a vacuum cleaner floor nozzle which has a suction opening on the underside, comprising an at least partially form-fitting receptacle for the vacuum cleaner floor nozzle with one associated with the suction opening.

SUMMARY OF THE INVENTION

The Applicant has studied the problem of reducing the pushing force in brushes for vacuum cleaners.

For the purposes of the present description and of the claims, the term "suction duct" or "duct" will mean a section of pipe comprised between the base plate channel and the joint.

The Applicant has thought that the most practical, efficient, and economical solution to reduce the pushing force is to provide one or more openings in the duct. According to the present invention, the opening (or openings) in the duct is (are) made in the duct molding phase and, preferably, is (are) of a dimension which is optimized for the intended use of the cleaning head and based on other technical characteristics, such as the performance of the vacuum cleaner.

According to a first aspect, the present invention provides a cleaning head for a vacuum cleaner or the like comprising:

- a base plate with a base plate channel open towards a surface to be sucked,

- a suction duct in fluid communication with the base plate channel,

- a joint at one end of the suction duct,

- a cover body,

- an opening in a surface, typically a lateral surface, of the suction duct to allow the passage of air.

According to embodiments, the surface of the suction duct where the opening is present faces at least partially the internal surface of the cover body.

According to embodiments, the surface of the suction duct is at a distance from the inner surface of the cover between about 1 mm and about 7 mm, for example between about 1 mm and about 3 mm.

According to embodiments, the cleaning head comprises a noise reduction element to reduce noise caused by air passage through the opening(s). This noise reduction element also acts to avoid that dust could exit from the opening(s). The noise reduction element may comprise a spongy material, for example a layer of elastic polyurethane foam.

The noise reduction element may comprise a net, a felt, a layer of nonwoven fabric or any layer of natural and/or synthetic fibers.

The opening may include at least one elongated opening.

The duct may comprise a removable closing piece.

The removable closing piece may comprise a curved portion and a female hemispherical portion configured to cooperate with a corresponding male hemispherical component.

The opening may be provided at the curved portion.

The removable closing piece may comprise through holes for fixing the closing piece by means of screws or other fixing systems to other components of the cleaning head.

According to embodiments, the area of the opening(s) is between 1 % and 5% of the mouth opening area, namely the area of the footprint of the base plate channel 3 on the floor to be vacuumed.

In embodiments, the area of the opening(s) is between 1.5% and 3% of the mouth opening area. In further embodiments, the area of the opening(s) is between about 1.8% and about 2.5% of mouth opening area.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become clearer from the following detailed description which follows, given purely by way of non-limiting example, to be read with reference to the attached figures, in which:

- Fig. 1.1 is an exploded view of a cleaning head according to the prior art;

- Fig. 1 .2 is an enlarged view of a part of the cleaning head of Fig. 1.1 ;

Fig. 1 .3 is an axonometric view of the base plate of the cleaning head of Fig. 1.1 ; - Fig. 2.1 is an exploded view of a cleaning head according to a first embodiment of the present invention;

- Fig. 2.2 is an enlarged view of a part of the cleaning head of Fig. 2.1 ;

- Fig. 2.3 is an axonometric view of the base plate of the cleaning head of Fig. 2.1 ;

- Fig. 3.1 is an exploded view of a cleaning head according to a second embodiment of the present invention;

Fig. 3.2 is a detailed view of a portion of the cleaning head of Fig. 3.1 ;

Fig. 3.3 is a further detailed view of a portion of the cleaning head of Fig. 3.1 ;

- Fig. 3.4 is an axonometric view of a part of cleaning head channel according to the present invention, as also shown in figures 3.1 , 3.2 and 3.3;

- Fig. 4.1 is an exploded view of a further cleaning head according to the prior art which can be modified to have a cleaning head according to the present invention;

- Fig. 4.2 is a detailed view of a portion of the cleaning head of Fig. 4.1 ;

- Fig. 5.1 is an exploded view of a still further cleaning head according to the prior art which can be modified to have a cleaning head according to the present invention;

- Fig. 5.2 is a detailed view of a portion of the cleaning head of Fig. 5.1.

DETAILED DESCRIPTION OF EMBODIMENTS

In the various figures, for the sake of clarity, some components considered non-essential for the present invention are not shown (or not disclosed in detailed manner).

The known cleaning head of Fig. 1.1 is indicated as a whole with the reference number 1. The cleaning head 1 is also shown in Figures 1.2 and 1 .3.

The cleaning head 1 comprises a base plate 2, a base plate channel 3, a duct 4, a joint 5 and a cover body 6, coupled to the base plate 2 and/or to the duct 4, typically in a removable way.

The base plate 2, during the use of the cleaning head 1 , faces the surface to be sucked. The base plate channel 3 is substantially shaped like an inverted U and is open towards the surface to be sucked. The duct 4 is connected to the channel 3 and ends at the joint 5. Also shown is an arrangement, comprising a crankshaft 7 supported by pylons projecting upwardly from the base plate, for moving a rubbered bar or brushes bar (parts to be used for hard floor cleaning) upwardly and downwardly.

According to the cleaning head of the prior art, the duct 4 has its lateral surface closed.

In Figures 2, similar reference numbers have been used, increased by ten.

Figures 2.1 , 2.2 and 2.3 show a cleaning head according to a first embodiment of the present invention.

Although the cleaning head 1 of the prior art has a duct 4 which has a closed lateral surface, the cleaning head 11 according to the present invention has a duct 14 which has one or more openings 18 at the lateral side.

According to the example embodiment of figures 2.1 , 2.2 and 2.3, the duct 14 has an elongate opening 18 and, possibly, at least a further opening.

When the cleaning head is finally assembled also with the cover part 16, the one or more openings 18 face the inner surface of the cover part 16.

Preferably, the openings 18 and the inner surface of the cover part 16 are at a short distance one from the other. Such a distance can be between 1 mm and 10 mm. The distance can be also in a smaller range, for instance between about 2 mm and about 9 mm or even smaller, for instance between about 2 mm and 3 mm.

According to embodiments, the space between the opening(s) 18 of the duct 14 and the inner surface of the cover 16 is substantially free of any further parts or components.

However, according to further embodiments, in the space between the opening(s) 18 of the duct 14 and the inner surface of the cover 16 there is provided a noise reduction element 19. The noise reduction element 19 can comprise a spongy material, for example a layer of elastic polyurethane foam, for example of the type derived from the polymerization of toluene diisocyanate. In other embodiments, the noise reduction element 19 comprises a net, a felt, a layer of non-woven fabric or any layer of natural and/or synthetic fibers.

As shown in figures 2, the openings 18 comprise two openings.

The area of the upper air opening of the embodiment shown in figures 2 is preferably between 50 mm ² and 90 mm ² , for example between 60 mm ² and 80 mm ² . In one embodiment is about 70 mm ² .

The area of the lower air opening of the embodiment shown in figures 2 is preferably between 10 mm ² and 25 mm ² , for example between 15 mm ² and 20 mm ² . In one embodiment is about 17 mm ² .

In one embodiment, the total area is about 87 mm ² .

Based on the fact that the area of the mouth opening is about 4982 mm ² , the area of the opening(s) 18 is about 1.75 % of the area of the mouth opening.

The Applicant has conducted several tests on suction nozzles mounted on vacuum cleaners of different types, from different manufacturers and with different powers.

Based on the tests which were conducted, the Applicant has concluded that it is preferable to have the area of the openings 18 in a certain relation with the area of the footprint of the base plate channel 3 (also known as “mouth opening area”) on the floor to be vacuumed.

In particular, the Applicant has obtained good results in terms of reduction of pushing force when the area of the opening(s) is between 1 % and 5% of the mouth opening area. In embodiments, the area of the opening(s) is between 1 .5% and 3% of the mouth opening area. In further embodiments, the area of the opening(s) is between about 1.8% and about 2.5% of mouth opening area.

When the opening(s) area is in the above relation with the mouth opening area, the pushing force drops down for about 35% till 40%, even up to 45%. The Applicant experienced values of pushing force drop from 62N to 41 N, and even more drop to about 37N-38N.

However, even with that low pushing force, proper dust pickup was achieved. The loss of dust pickup was about 3%-5%, more precisely around 4%.

In Figures 3, similar reference numbers have been used, increased by thirty.

Fig. 3.1 shows a cleaning head 31 according to the present invention.

Cleaning head 31 comprises a base plate 32 with a base plate channel, a duct 34 and a joint 35. In the cleaning head of the present invention, the duct 34 has a lateral surface provided with one or more openings 38. According to the embodiment which is shown, the duct 34 comprises a removable closing piece 341 , shown also in Figures 3.2, 3.3 and 3.4.

The closing piece 341 comprises a curved portion 345 and a female hemispherical portion 346 configured to cooperate with a corresponding male hemispherical component.

The closing piece 341 comprises through holes 343 for fixing the closing piece, for example by means of screws 342, to other components of the cleaning head 31 .

The cleaning head of figures 3, thanks to the opening(s) 38, improves handling by properly reducing the pushing force.

According to embodiments, a noise reduction element 39 can be provided between the closing piece and the cover body 36. The noise reduction element 39 can comprise a spongy material, for example a layer of elastic polyurethane foam, for example of the type derived from the polymerization of toluene diisocyanate. In other embodiments, the noise reduction element 39 comprises a net, a felt, a layer of non-woven fabric or any layer of natural and/or synthetic fibers.

According to the embodiment of Figure 3.4, the one or more openings 38 are provided at the curved portion 345. For instance, the openings 38 can comprise an upper opening and a lower opening.

The openings 38 can be elongated.

The openings 38 can have a substantially parallel axis.

According to other embodiments, the space between the opening(s) 38 of the duct 34 and the inner surface of the cover body 36 is substantially free of any further parts or components.

Preferably, the openings 38 and the inner surface of the cover part 36 are at a short distance one from the other. Such a distance can be between 1 mm and 10 mm. The distance can be also in a smaller range, for instance between about 2 mm and about 9 mm or even smaller, for instance about 2 mm and 3 mm.

As shown in figures 3, the openings 38 comprise two openings.

The area of the upper air opening of the embodiment shown in figures 3 is preferably between 35 mm ² and 65 mm ² , for example between 45 mm ² and 55 mm ² . In one embodiment is about 50 mm ² .

The area of the lower air opening of the embodiment shown in figures 3 is preferably between 60 mm ² and 90 mm ² , for example between 65 mm ² and 85 mm ² . In one embodiment is about 75 mm ² .

In one embodiment, the total area is about 126 mm ² . Based on the fact that the area of the mouth opening is about 5227 mm ² , the area of the opening(s) 38 is about 2.41 % of the area of the mouth opening.

The considerations given above in connection with the embodiment of figure 2 are still valid for the embodiment of figure 3.

It is now clear that the invention provides one or more openings in the duct.

Openings in the duct can be provided also in cleaning heads shaped differently from those shown in the figures disclosed above.

In figures 4, similar reference numbers have been used, increased by forty.

For instance, with reference to figures 4.1 and 4.2, the opening(s) 48 can be provided at any position of the duct 44 as shown in the figures.

The number, the position and the area of the opening(s) can be decided by the manufacturer during the design process according to specific evaluations, including the power of the motor of the vacuum cleaner.

In figures 5, similar reference numbers have been used, increased by fifty.

With reference to figures 5.1 and 5.2, the opening(s) 58 can be provided at any position of the duct 54 as shown in the figures.

The number, the position and the area of the opening(s) 58 can be decided by the cleaning head manufacturer during the design process according to specific evaluations, including the airflow of the vacuum cleaner and/or further parameters.

The present invention provides several advantages over the known solutions. In particular, it should be remarked that the openings in the duct are obtained by modifying only a mold. It is clear that working only on one mold, allows (having interchangeable inserts) to optimize the nozzle performance based on different customers’ cleaner airflow rate at the design stage. Therefore, the final user does not need to work on manual nozzle setting during the cleaning operations.