Patent Description:
Vacuum cleaners are known in the art and used in many households. One generally distinguishes cylinder vacuum cleaners, stick vacuum cleaner, upright vacuum cleaners and vacuum cleaner robots. Except of vacuum cleaner robots, the other types generally have a suction tube with a distal end (the end that points away from the user). Usually, a replaceable nozzle is attached to the distal end during cleaning. Dirt, dust, and the like (jointly "dirt" herein) is sucked via the nozzle into the suction tube and conveyed by an airflow to a dirt reservoir.

<CIT> and <CIT> disclose a respective vacuum cleaner with a fragmentation unit arranged within a conduit of the vacuum cleaner, the fragmentation unit being movably supported by the conduit.

<CIT> discloses a mosquito killing device with a suction device and a pair of meshes for fragmenting insects sucked in by the suction device, the suction device and the meshes being arranged in a conduit of the mosquito killing de vice. The mosquito killing device may be used as part of a vacuum cleaner.

<CIT> discloses a mosquito killing device with a combined suction and fragmentation unit arranged within a conduit of the mosquito killing device.

The invention is based on the observation that vacuum cleaners are often used to remove insects from places where they are considered disturbing. Some people suffer from insect phobia in general, or kinds thereof, e.g., arachnophobia and some of these fear that insects sucked in by a vacuum cleaner are not killed by the removal process but might be able to escape from the dirt reservoir.

The problem to be solved by the invention is to provide a device that reliably kills insects, in particular spiders.

Solutions of the problem are described in the independent claims. The dependent claims relate to further improvements of the invention.

A solution is provided by a suction tube nozzle or a suction tube extension for a suction tube of a vacuum cleaner. The suction tube nozzle or suction tube extension is preferably configured to be connected to the distal end of a suction tube of a vacuum cleaner. Hereinafter, we will not distinguish between a suction tube nozzle or a suction tube extension, both terms are used interchangeably, i.e., suction tube nozzle shall be understood as suction tube nozzle and/or suction tube nozzle extension and vice versa.

The suction tube nozzle may comprise a conduit having a conduit wall with an inlet opening (hereinafter "inlet") and an outlet opening (hereinafter "outlet"). The conduit wall may enclose a conduit volume extending from the inlet to the outlet. The inlet and the outlet are thus in fluid communication via the conduit volume. The conduit wall has a first end that may define, e.g., by radially delimiting, the inlet and a second end that may define the outlet, e.g., by radially delimiting the outlet. This does not imply that the inlet and outlet are necessarily rotationally symmetric, but that the inlet and the outlet may be delimited by the conduit wall in a radial direction, i.e., in a direction that points radially away from a conduit axis, assuming the conduit is a straight conduit. If the conduit is not straight, the term conduit axis can be replaced by neutral axis. Herein, we will use the term longitudinal axis for conceptional simplicity. It is understood by a person of skill in the art that the term has to be replaced by a more suitable term if the conduit is not straight. The longitudinal axis may be understood as a line that extends from the center of the inlet to the center of the outlet, while being centered with respect to the contour of an inner surface of the conduit.

The second end is preferably configured to be connected to a distal end of a suction tube to thereby provide a fluid communication between the inlet and the suction tube.

If the conduit comprises at least a first rotary bearing with a first rotational axis, which bearing movably supports at least a first rotary blade or a first set of rotary blades in the conduit volume relative to the conduit wall, this (these) rotary blade(s) may be driven to rotate relative to the conduit wall and cut insects sucked in via the inlet into pieces to thereby ensure that only dead insects leave the outlet. The risk of sucking living insects in a dirt reservoir of a vacuum cleaner no longer exists. Insects that have been sucked in via the suction tube nozzle may hence not "escape" from the dirt reservoir and cannot frighten or otherwise harm persons. Herein, we use the term first rotary blade only for conceptual simplicity. The first rotary blade may be a set of first rotary blades, wherein each rotary blade of the set is configured to rotate with the same rotational speed as the other members of the set. For example, the members of the first set of rotary blades may be attached to a first hub.

In a preferred example, the suction tube nozzle comprises a second rotary blade or a second set of rotary blades being as well rotatably supported relative to the housing wall by the first rotary bearing and/or a second rotary bearing. The second rotary blade may comprise the second rotary bearing, which second rotary bearing may have a second rotational axis. At least one of the first rotary bearing and the second rotary bearing may movably support the second rotary blade inside the conduit volume relative to the conduit wall. Like the term first rotary blade shall be understood to mean one first rotary blade or a first set of rotary blades, the term "second rotary blade" shall be understood to mean one "second rotary blade or second set of rotary blades". Again, a set of rotary blades is driven or interconnected to rotate with the same rotational speed.

Preferably, the at least one first rotary blade is a rotary turbine blade having a first direction of rotation based on an assumed gas flow from the inlet through the conduit volume towards the outlet. Thus, when attaching the suction tube nozzle to a suction tube of an operating vacuum cleaner, the airflow through the conduit volume drives the first rotary blade to rotate in the first direction. This keeps cost for the suction tube nozzle low, as no motors, gears or the like are required to operate the first rotary blade. Further, clutches or other means to avoid overstressing the drive train when an insect abruptly slows the rotating rotary blade down can be avoided as well.

The optional second rotary blade may be a rotary turbine blade having a second direction of rotation, based on an assumed gas flow from the inlet through the conduit volume towards the outlet. This second direction of rotation is preferably opposite to the first direction of rotation. Assuming the first rotary blade to be upstream of (i.e., closer to the inlet than) the second rotary blade, particles of an insect that are transported with the airflow have an angular moment pointing in the same direction as the angular momentum of the first rotary blade, because hitting an insect transfers a portion of the rotary blade's angular momentum onto the insect and/or its particles. The relative angular velocity of the second rotary blade to these insects/particles is hence increased and lower mass particles are cut into pieces with a higher probability. In short, the risk that an insect 'passes' the suction tube nozzle without being killed is reduced by the second rotary blade rotating opposite to the first rotary blade. Only to avoid misunderstandings, the same technical effect can be observed in case the second rotary blade is located upstream of the first rotary blade. However, it is of course preferred that the first and the second rotary blades are downstream or upstream of the respective other second or first rotary blade.

As already apparent, the first rotational axis and the second rotational axis are preferably at least essentially identical and/or at least essentially parallel. This measure reduces the pressure gradient between the inlet and the outlet and further contributes to the technical effect of reducing the risk that an insect passes the sequence of rotary blades.

According to the invention, the suction tube nozzle comprises at least one static blade with at least a first and/or a second static cutting edge. In a preferred example the first static cutting-edge faces towards a first rotary cutting edge of the first rotary blade and/or the second static cutting edge faces towards a second rotary cutting edge of the second rotary blade. Face towards each other shall herein be understood to the express that the first static cutting edge provides a (cutting) abutment for an insect being loaded by the first rotary cutting edge. The abutment does not need to prevent any movement, but instead the two cutting edges may form an angle relative to each other. In both cases, cutting insects transported by the airflow from the inlet to the outlet is enhanced. As already apparent, the optional static cutting edge(s) may complement the respective rotary cutting edge(s).

In a preferred example, at least one static blade axially supports the first rotary blade and/or the second rotary blade. This measure provides a reduction of the manufacturing cost and at the same reduces the pressure gradient between the inlet and the outlet and avoids that insects may get stuck at support structures extending in the conduit volume to support the rotary blade(s). In a particular preferred example, the static cutting edge of the at least one static blade provides an axial abutment supporting at least one rotary blade (of the above-mentioned rotary blades). Hence, in operation, the axially supported rotary blade may slide with its rotary cutting edge over the static cutting edge, thereby ensuring that any insect being in between of these cutting edges relatively moving towards each other is reliably cut by these cutting edges.

It is particularly preferred if the at least one static blade radially supports the rotary bearing and/or defines a bearing surface of the rotary bearing. This measure further contributes to reducing manufacturing costs and the flow resistance of the suction tube nozzle.

An axle and/or a shaft may extend in the conduit volume. The axle is preferably radially and/or axially supported by at least one strut extending from the inner wall surface towards the rotational axis of the first rotational bearing and/or the second rotational. The at least one strut can be configured as one of the optional static blades explained above. In other words, at least one strut may be a static blade and/or at least one static blade may be a strut. Accordingly, at least one static blade may extend from the inner wall towards the longitudinal axis and support the axle and/or the shaft radially and/or axially.

The axle may rotatably support the first rotary blade and optionally the second rotary blade, e.g., by the respective rotary bearing. This is a very cost efficient and reliable measure to rotatably support one or more rotary blades in the conduit volume, independently from each other.

Alternatively, a shaft may be rotatably supported in the conduit volume by the first and/or the second rotational bearing and the first rotary blade and/or the second rotary blade may be mounted to the shaft.

The first rotary bearing and/or the second rotary bearing may be a first fluid bearing and/or a second fluid bearing, respectively. Such fluid bearings reduce wear and allow for very high rotational speeds of the correspondingly supported rotary blades.

Preferably, the first fluid bearing and/or the second fluid bearing may comprise a first gas inlet and/or a second gas inlet and a first gas outlet and/or a second gas outlet, respectively. The first gas inlet and/or the second gas inlet may preferably face towards the inlet of the conduit and the first gas outlet and/or the second gas outlet, respectively, may preferably face towards outlet of the conduit. In operation, the pressure gradient between the first gas inlet and/or the second gas inlet and the first gas outlet and/or the second gas outlet, respectively, provides for a gas flow through the respective fluid bearing. Hence, no additional gas source is required to provide the fluid flow being required to operate the fluid bearings.

It is preferred, if at least one of the first rotary blade and/or the second rotary blade and/or the static blade and/or a strut are/is located in between of the first gas inlet and the first gas outlet of the first fluid bearing and/or in between of the second gas inlet and the second gas outlet of the second fluid bearing. "in between" references to the respective axial position assuming the conduit to have a longitudinal axis. The blade(s) and/or the strut(s) provide for an increased pressure gradient between the respective gas inlet and gas outlet. Thereby, the gas flow through the fluid bearings is enhanced.

In another example, at least one of the rotational bearings is a plain bearing. A first bearing surface may be attached and/or integrally formed by the first rotary blade and/or the second rotary blade. The complementary other bearing surface may be provided by the peripheral surface of the axle and/or the conduit's wall inner surface, i.e., the surface of the conduit wall that faces towards the longitudinal axis.

Herein, the term "connection" and the corresponding verb "to connect" shall be understood not only as a mechanical connection, but as well as function enhancing connection. For example, two conduits are connected with each other if the mechanical connection provides for a fluid communication between the two pipes. In the example of a suction pipe and a suction pipe nozzle, a connection of these two elements would allow to suck a fluid via the nozzle inlet into the suction pipe.

Further, as will become apparent below, an expression like b E A, A = {c, d, e, f} or simply b ∈ {c, d, e, f} indicates that be b can be selected as appropriate to take any value comprised in the set A.

In the following. the invention will be described by way of example, without limitation of the general inventive concept, on examples of embodiment with reference to the drawings.

<FIG> shows a sketch of longitudinal section along plane B-B as indicated in <FIG> of an example suction tube nozzle <NUM>. The suction tube nozzle <NUM> may comprise a conduit <NUM> with a longitudinal axis <NUM>. The preferred flow direction is indicated by an arrow <NUM>. The conduit <NUM> has a conduit wall <NUM> with an inner wall surface <NUM>, a first end <NUM> and a second end <NUM>. The first end <NUM> may radially delimit the inlet opening <NUM> ("inlet <NUM>") and the second end <NUM> may radially delimit the outlet opening <NUM> ("outlet <NUM>"). The terms Inlet <NUM> and outlet <NUM> reference to the preferred flow direction <NUM>.

A first set of static blades <NUM> extends from the conduit wall <NUM> towards the longitudinal axis <NUM>. In the example (see <FIG>), four first static blades <NUM> are shown, but other integer numbers n<NUM> (n<NUM> ∈ {<NUM>,<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>,. }) are possible as well. A second optional set of n<NUM> second static blades <NUM>, i.e., a second set of static blades <NUM> extends downstream of the first set of static blades <NUM> towards the longitudinal axis <NUM> ((n<NUM> ∈ {<NUM>,<NUM>, <NUM>, <NUM>,<NUM>, <NUM>, <NUM>, <NUM>,.

At least some of the static blades <NUM>, <NUM>, preferably all of them, support an axle <NUM>. The axle <NUM> is preferably at least essentially aligned with preferred flow direction <NUM> and/or the longitudinal axis <NUM>. "At least essentially aligned" shall indicate that a perfect alignment is preferred but that deviations from perfect alignment within an angle of ±αdev can be accepted (αdev ∈ {<NUM>°, <NUM>°, <NUM>°,<NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°}, wherein smaller values of αdev are preferred).

The axle <NUM> may rotatably support a first set of rotary blades <NUM> and/or a second set of rotary blades <NUM> by corresponding rotary bearings. As shown the two sets of rotary blades <NUM>, <NUM> may be sets of turbine blades. The two sets of rotary blades <NUM>, <NUM> may have opposite directions of rotation (see arrows135, <NUM>).

The bearings may be plain bearings, i.e., the peripheral surface of the axle <NUM> may form a first bearing surface and a recess in the respective set of rotary blades <NUM>, <NUM> may provide as second plain bearing surface. Of course, the recess may as well be sleeved and in this case the sleeve may provide the respective bearing surface. However, it is preferred, if the bearings are fluid bearings with a gas inlet <NUM>, <NUM> and a gas outlet <NUM>, <NUM>. Preferably, the gas inlet <NUM>, <NUM> faces towards the inlet <NUM> of the conduit <NUM> and preferably the gas outlet <NUM>, <NUM> faces in the opposite direction, wherein the gas inlet <NUM>, <NUM> is preferably in fluid communication with the corresponding gas outlet <NUM>, <NUM> via a moving gap between the respective rotary blade <NUM>, <NUM> and the axle <NUM>.

Claim 1:
A suction tube nozzle (<NUM>) comprising at least a conduit (<NUM>) with an inlet (<NUM>), an outlet (<NUM>) and a conduit wall (<NUM>) enclosing a conduit volume (<NUM>), wherein:
(i) the conduit wall (<NUM>) has a first end (<NUM>) and a second end (<NUM>) and an inner wall surface (<NUM>),
(ii) the first end (<NUM>) defines the inlet (<NUM>), and the second end (<NUM>) defines the outlet (<NUM>), and
(iii) the second end (<NUM>) is configured to be connected to a distal end of a suction tube to thereby provide a fluid communication between the inlet (<NUM>) and the suction tube,
(iv) a first rotary bearing with a first rotational axis (<NUM>) movably supports at least one first rotary blade (<NUM>) inside the conduit volume (<NUM>) relative to the conduit wall (<NUM>),
characterized in that
the suction tube nozzle (<NUM>) further comprises a static blade (<NUM>, <NUM>) with at least a first and/or a second static cutting edge (<NUM>), wherein the first static cutting edge (<NUM>) faces towards a first rotary cutting edge (<NUM>) of the first rotary blade (<NUM>) and/or the second rotary cutting edge (<NUM>) faces towards a static cutting edge of the second static blade (<NUM>).