WO2024088775A1

WO2024088775A1 - Surface-cleaning head

Info

Publication number: WO2024088775A1
Application number: PCT/EP2023/078331
Authority: WO
Inventors: Patrick Foltyn; Andreas FRIEDERICH; Tobias GELTZ
Original assignee: Alfred Kärcher SE & Co. KG
Priority date: 2022-10-27
Filing date: 2023-10-12
Publication date: 2024-05-02
Also published as: DE102022128567A1

Abstract

The invention relates to a surface-cleaning head for cleaning a surface (11), having a dome-shaped housing (12) which, in a horizontal position of use of the surface-cleaning head (10), is open at the bottom, and in which at least one spray arm (40, 42) having a cleaning nozzle (44, 46) is mounted rotatably about an axis of rotation (32), wherein pressurized cleaning liquid can be supplied to the cleaning nozzle (44, 46), and the cleaning nozzle (44, 46), together with the spray arm (40, 42), orbits around the axis of rotation (32) in order to apply a jet of liquid to the surface (11) that is to be cleaned. To develop the surface-cleaning head in such a way that it provides a higher cleaning performance, it is proposed that the surface-cleaning head has an oscillation device (50; 212; 246; 272; 282; 302) for generating temporal and/or spatial oscillations of the jet of liquid that is output from the cleaning nozzle.

Description

SURFACE CLEANING HEAD

The invention relates to a surface cleaning head for cleaning a surface, with a hood-shaped housing which is open downwards in a horizontal position of use of the surface cleaning head and in which at least one spray arm with a cleaning nozzle is mounted so as to be rotatable about an axis of rotation, wherein pressurized cleaning liquid can be supplied to the cleaning nozzle and the cleaning nozzle rotates together with the spray arm about the axis of rotation to apply a jet of liquid to the surface to be cleaned.

Such surface cleaning heads are known from DE 10 2007 029 245 A1. They are particularly suitable for cleaning hard surfaces, for example stone or wooden terraces, garage entrances and garage doors. To clean the surfaces, the pressure line of a high-pressure cleaning device can be connected to the surface cleaning head. Pressurized cleaning fluid, in particular water, can be supplied to the surface cleaning head via the pressure line. The surface cleaning head has at least one spray arm that is mounted so that it can rotate about an axis of rotation and that carries a cleaning nozzle. The pressurized cleaning fluid can be fed to the cleaning nozzle. The cleaning nozzle can be used to apply a jet of fluid to the surface to be cleaned, with the at least one spray arm rotating around the axis of rotation together with the cleaning nozzle attached to it. Usually, at least two or three spray arms are used, each of which carries a cleaning nozzle, with all of the cleaning nozzles being able to be supplied with pressurized cleaning fluid at the same time and the cleaning nozzles performing a circular movement around the axis of rotation.

Such surface cleaning heads have proven themselves. However, it is desirable to increase the cleaning performance of the surface cleaning heads. The object of the invention is therefore to further develop a surface cleaning head of the type mentioned at the beginning in such a way that it has a higher cleaning performance.

This object is achieved according to the invention in a surface cleaning head of the generic type in that the surface cleaning head has an oscillation device for generating temporal and/or spatial oscillations of the liquid jet.

The oscillation device can be used to generate a liquid jet that oscillates in time and/or space and can be directed at the surface to be cleaned. The oscillations of the liquid jet cause the liquid jet emerging from the cleaning nozzle to disintegrate, so that it at least partially breaks down into individual liquid droplets on the way from the cleaning nozzle to the surface to be cleaned, and individual droplets then hit the surface to be cleaned. This leads to a so-called water hammer effect, which leads to an increased impact force of the liquid, which significantly increases the cleaning performance. The effect of the high impact force of the droplets can remove even stubborn dirt from the surface to be cleaned without the need for subsequent treatment of the surface. The increased cleaning performance also has the advantage that the surface cleaning head can be moved along the surface to be cleaned at a higher speed and that cleaning liquid and energy can be saved when cleaning the surface.

The liquid jet emitted by the cleaning nozzle attached to a spray arm not only performs a circular movement around the rotation axis of the spray arm, but also exhibits temporal and/or spatial oscillations, under the effect of which the liquid jet emitted by the cleaning nozzle is at least partially broken down into individual drops. The individual liquid drops do not necessarily have to be completely separated from each other, it can also be provided that the drops are connected to each other via narrow liquid bridges (liquid ligaments) so that the liquid jet forms a modulated or pulsed liquid flow.

The temporal oscillations can be, for example, pressure fluctuations in the flow direction of the liquid jet. The spatial oscillations can be, for example, an additional pendulum movement of the liquid jet. The pendulum movement is preferably aligned transversely to the circular movement of the liquid jet around the axis of rotation.

In the case of spatial oscillation of the liquid jet, the oscillation frequency is preferably at least 10 Hz, in particular 10 Hz to 3,000 Hz.

In the case of a temporal oscillation of the liquid jet, the oscillation frequency is preferably 10 kHz to 30 kHz, in particular 20 kHz to 25 kHz.

The rotational speed of the at least one spray arm is preferably a maximum of 15,000 revolutions per minute, in particular 1,000 to 3,000 revolutions per minute, for example 1,500 to 2,000 revolutions per minute.

In a preferred embodiment of the invention, the oscillation frequency of the liquid jet is at least as high as the rotational speed of the at least one spray arm.

It is particularly advantageous if the oscillation frequency of the liquid jet is a multiple of the rotational speed of the at least one spray arm. In such a configuration, the liquid jet emitted by the cleaning nozzle performs a large number of oscillations during one rotation of the spray arm about the axis of rotation, which result in the liquid jet disintegrating by at least partially dissolving into individual liquid drops. In a preferred embodiment of the surface cleaning head according to the invention, the oscillation device is integrated into the cleaning nozzle arranged on the at least one spray arm. This enables a particularly compact design of the surface cleaning head.

It is advantageous if the cleaning nozzle has a through-channel and the oscillation device forms a flow chamber in the through-channel in which a flow guide element is arranged to generate a spatial oscillation of the liquid jet emitted by the cleaning nozzle. With the help of the flow guide element, the cleaning liquid flowing through the through-channel of the cleaning nozzle can be given a pendulum movement transverse to the longitudinal axis of the through-channel, so that the liquid jet emerging from the cleaning nozzle performs a pendulum movement in addition to its circular movement around the axis of rotation of the spray arm. This allows the liquid jet to be at least partially broken down into individual drops that hit the surface to be cleaned with high impact force.

In a preferred embodiment of the invention, the flow guide element divides the flow chamber of the cleaning nozzle into a central flow channel and two feedback channels lying opposite one another, the feedback channels connecting an output section of the central flow channel to an input section of the central flow channel. The pressurized cleaning liquid can flow through the central flow channel, with part of the cleaning liquid being returned from the output section of the central flow channel to its input section via the feedback channels. The mouth areas of the feedback channels in the input section of the central flow channel are preferably located opposite one another, so that the cleaning liquid flows returned via the feedback channels meet in the input section of the central flow channel and, due to flow instabilities, the cleaning liquid flowing through the central flow channel Cleaning fluid is stimulated to lateral deflections in successive and opposing directions. A resonance oscillation is thus induced in the central flow channel, which results in the liquid jet emerging from the cleaning nozzle performing a pendulum motion in addition to its circular motion around the axis of rotation of the spray arm, under the effect of which it at least partially disintegrates into individual drops.

Preferably, the central flow channel has an inlet section, which is successively followed by a first lens-shaped section and a second lens-shaped section, wherein the first lens-shaped section is longer than the second lens-shaped section and the second lens-shaped section forms the outlet section of the central flow channel.

Preferably, the length of the first lens-shaped portion is at least 1.3 times the length of the second lens-shaped portion.

A flow separation edge is preferably arranged between the first lens-shaped section and the second lens-shaped section.

In an advantageous embodiment of the surface cleaning head according to the invention, the oscillation device is designed as a pulsation device for generating temporal oscillations in the form of pressure fluctuations of the liquid jet that is emitted by the cleaning nozzle held on a spray arm. The pressure fluctuations lead to a partial or complete dissolution of the liquid jet into individual drops at a short distance from the cleaning nozzle, which impact the surface to be cleaned with high impact force under the effect of the water hammer effect.

It is advantageous if the cleaning fluid can be subjected to pressure pulses by means of the pulsation device. In an advantageous embodiment of the surface cleaning head according to the invention, the pulsation device has a resonator chamber which forms a pressure resonator for applying pressure pulses to the cleaning liquid. The resonator chamber can be designed, for example, in the form of a Helmholtz resonator. In particular, it can be provided that axially aligned pressure fluctuations can be achieved in the cleaning liquid with respect to its flow direction by means of the resonator chamber.

The resonator chamber can, for example, form a cylindrical cavity with an inlet opening and an outlet opening through which the cleaning fluid can flow. In such a design, the inlet opening of the cavity is followed by a step that is directed radially outwards in relation to the flow direction of the cleaning fluid, at which the flow of the cleaning fluid separates so that vortices are formed that move within the cylindrical cavity in the flow direction, with a resonance vibration forming in the cavity, which results in axially aligned pressure fluctuations in the cleaning fluid.

The resonator chamber can be integrated into the cleaning nozzle.

Alternatively, it can be provided that the cleaning fluid that can be fed to the cleaning nozzle can flow through the resonator chamber. In such an embodiment of the invention, the resonator chamber is arranged upstream of the cleaning nozzle.

For example, it can be provided that the resonator chamber is arranged in the at least one spray arm.

In particular, it can be provided that the resonator chamber is arranged directly upstream of the cleaning nozzle. In such an embodiment of the invention, the at least one spray arm has a region to which the cleaning nozzle is connected and in which the resonator chamber is located.

It can also be provided that the resonator chamber is arranged upstream of the at least one spray arm.

In an advantageous embodiment of the invention, the pulsation device has at least one piezoceramic part to which an alternating electrical voltage can be applied, wherein the cleaning liquid can be subjected to pressure pulses by the at least one piezoceramic part. The application of the alternating electrical voltage to the at least one piezoceramic part results in a periodic expansion and contraction of the at least one piezoceramic part, so that the cleaning liquid contacting the at least one piezoceramic part is subjected to pressure pulses that cause pressure fluctuations in the cleaning liquid. The pressure fluctuations lead to a disintegration of the liquid jet emerging from the cleaning nozzle.

It is advantageous if at least one piezoceramic part has a passage through which the cleaning fluid can flow. Due to the application of the alternating electrical voltage to the piezoceramic part, the flow cross-section of the passage changes periodically. By reducing and increasing the flow cross-section, pressure pulses are exerted on the cleaning fluid flowing through the passage, which result in pressure fluctuations spreading in the direction of flow of the cleaning fluid and cause disintegration of the cleaning fluid emerging from the cleaning nozzle.

It is particularly advantageous if the pulsation device has a first and a second piezoceramic part, wherein the first piezoceramic part has a passage channel in which the second piezoceramic part is arranged to form an annular gap, wherein the annular gap is filled with cleaning fluid. liquid can flow through. With such a design, the cleaning liquid can be subjected to pressure pulses from both the first piezoceramic part and the second piezoceramic part. The cleaning liquid flows around the second piezoceramic part arranged in the passage channel of the first piezoceramic part, so that very strong pressure fluctuations develop in the cleaning liquid, which result in disintegration of the liquid jet emerging from the cleaning nozzle.

Alternatively or additionally, the pulsation device can have at least one piezoceramic part that is cuboid-shaped or cylindrical and has a pressure application surface on one end face for applying pressure pulses to the cleaning fluid. The cuboid-shaped or cylindrical piezoceramic part can form a type of piston that has a pressure application surface, wherein the pressure application surface is excited to mechanical vibrations due to the application of the alternating electrical voltage to the piezoceramic part. The cleaning fluid can flow along the pressure application surface and be subjected to pressure pulses by it.

The electrical alternating voltage can be provided by means of external control electronics, which can be connected to the surface cleaning head via an electrical connecting cable.

It is particularly advantageous if the surface cleaning head has a battery-operated alternating voltage generator for applying an electrical alternating voltage to the at least one piezoceramic part. With such a design of the surface cleaning head according to the invention, an electrical connection to external control electronics can be omitted.

In an advantageous embodiment, the surface cleaning head according to the invention has an inlet upstream of the at least one spray arm channel for the pressurized cleaning fluid, wherein the cleaning fluid in the region of the inlet channel can be subjected to pressure pulses by means of the pulsation device. In such an embodiment of the invention, the pressurized cleaning fluid provided to the surface cleaning head is subjected to pressure pulses upstream of the at least one spray arm.

For example, it can be provided that the inlet channel has at least one radial extension in which at least one piezoceramic part to which an alternating electrical voltage can be applied is arranged or which forms a resonator chamber, wherein the resonator chamber can be flowed through by the pressurized cleaning fluid.

The cleaning nozzle held on a spray arm experiences a recoil when the liquid jet is released. It can be provided that the spray arm is set in rotation about the axis of rotation under the effect of the recoil. In this case, it is advantageous if the orientation of the cleaning nozzle in the direction of the surface to be cleaned can be adjusted. This allows the inclination of the cleaning nozzle, which it assumes in a horizontal position of use of the surface cleaning head relative to the vertical, to be changed. The more the cleaning nozzle is inclined to the vertical, the greater the horizontal force component of the recoil that is exerted by the cleaning nozzle on the associated spray arm when the liquid jet is released. This in turn leads to a stronger acceleration of the spray arm, i.e. to a higher speed of the spray arm. The high cleaning performance that can be achieved by means of the surface cleaning head according to the invention allows the surface cleaning head to be moved along the surface to be cleaned at a relatively high speed. In this case, the at least one spray arm should have a relatively high speed. A high speed can be easily achieved by a relatively strong inclination of the cleaning nozzle held on the spray arm relative to the vertical. However, if the surface to be cleaned has very stubborn dirt If necessary, the inclination of the cleaning nozzle to the vertical can be reduced in order to also reduce the speed of at least one spray arm.

For example, it can be provided that the at least one spray arm has an inner and an outer spray arm section relative to the rotation axis, wherein the cleaning nozzle is held on the outer spray arm section and the outer spray arm section can be detachably connected to the inner spray arm section in different rotational positions relative to the longitudinal axis of the spray arm. Depending on the rotational position that the outer spray arm section has relative to the inner spray arm section, the cleaning nozzle held on the outer spray arm section has a different inclination to the vertical, so that the entire spray arm has a speed that depends on the rotational position of the outer spray arm section.

In order to increase the speed of the at least one spray arm, it can be provided that an additional nozzle for dispensing cleaning fluid is arranged on the at least one spray arm and is aligned tangentially with respect to the direction of rotation of the spray arm. The tangential alignment of the additional nozzle exerts a recoil on the spray arm, which leads to an acceleration of the spray arm so that it rotates around the axis of rotation at high speed. The additional nozzle can have a significantly smaller nozzle opening than the cleaning nozzle held on the spray arm, so that the flow rate of the cleaning fluid dispensed via the additional nozzle can be kept low and a considerable recoil can still be exerted on the spray arm.

The rotational drive of the at least one spray arm can also be carried out using a turbine wheel. For this purpose, in an advantageous embodiment, the surface cleaning head according to the invention has a turbine wheel that is connected in a rotationally fixed manner to the at least one spray arm and that can be acted upon by the cleaning liquid that can be fed to the cleaning nozzle. Under the effect of the pressurized cleaning liquid that the turbine wheel When the pressure is applied, the turbine wheel and with it at least one spray arm are set in rotation around the axis of rotation.

It can also be provided that the surface cleaning head has a motorized rotary drive, wherein the at least one spray arm can be set in rotation about the axis of rotation by means of the rotary drive.

It is advantageous if the surface cleaning head has a battery, in particular a rechargeable battery, to supply energy to the rotary drive.

In an advantageous embodiment of the surface cleaning head, the rotation axis of the at least one spray arm is inclined to the vertical in a horizontal position of use of the surface cleaning head. In such an embodiment, the at least one spray arm rotates in a rotation plane that is aligned at an angle to the horizontal. This means that the cleaning nozzle arranged on the spray arm changes its distance from the surface to be cleaned during a circular movement around the rotation axis, so that the disintegration of the liquid jet emitted by the cleaning nozzle takes place at different distances from the surface to be cleaned and thus the liquid jet at least partially dissolves into individual drops at different distances from the surface to be cleaned.

The following description of advantageous embodiments of the invention serves to explain in more detail in conjunction with the drawing. They show:

Figure 1: a vertical sectional view of a first embodiment of a surface cleaning head;

Figure 2: an enlarged view of detail X from Figure 1;

Figure 3: a bottom view of the surface cleaning head from Figure 1; Figure 4: a vertical sectional view of a second embodiment of a surface cleaning head;

Figure 5: a perspective view of the surface cleaning head from Figure 4, viewed obliquely from below;

Figure 6: a vertical sectional view of a third embodiment of a surface cleaning head;

Figure 7: a vertical sectional view of a fourth embodiment of a surface cleaning head;

Figure 8: a bottom view of the surface cleaning head from Figure 7;

Figure 9: a vertical sectional view of a fifth embodiment of a surface cleaning head;

Figure 10: a vertical sectional view of a sixth embodiment of a surface cleaning head;

Figure 11: a vertical sectional view of a seventh embodiment of a surface cleaning head;

Figure 12: a vertical sectional view of an eighth embodiment of a surface cleaning head;

Figure 13: a vertical sectional view of a ninth embodiment of a surface cleaning head;

Figure 14: a vertical sectional view of a tenth embodiment of a surface cleaning head; Figure 15: a vertical sectional view of an eleventh embodiment of a surface cleaning head.

Figures 1, 2 and 3 show a first advantageous embodiment of a surface cleaning head according to the invention schematically. The surface cleaning head is designated overall by the reference number 10 and has a hood-shaped housing 12 which, in the horizontal position of use shown, is open downwards in the direction of a surface 11 to be cleaned and has a top wall 14 from which a circular, self-contained side wall 16 projects downwards, which has a circumferential splash guard element 20 on its free edge 18. The splash guard element 20 can be designed, for example, in the form of a bristle strip.

The top wall 14 has a central opening 22 through which a connecting part 24 passes. The connecting part 24 forms an inlet channel 26, to the end 28 of which facing away from the housing 12 a pressure line of a high-pressure cleaning device can be connected, which is known per se and is not shown in the drawing for the sake of clarity. The pressure line can be used to provide the surface cleaning head 10 with cleaning fluid that has been pressurized by the high-pressure cleaning device.

In the connecting part 24, a tubular connecting part 30 is mounted so as to be rotatable about a rotation axis 32 which is vertically aligned in the illustrated horizontal position of use of the surface cleaning head 10. Bearing elements designed in the form of a first ball bearing ring 34 and a second ball bearing ring 36 are used to rotatably mount the connecting part in the connecting part 24.

The connecting part 30 has an end section 38 which projects downwards from the connecting part 24 in the direction away from the inlet channel 26 and on which two diametrically opposed spray arms 40, 42 are held in a rotationally fixed manner. At their free ends, the two spray arms 40, 42 each have a cleaning nozzle 44 or 46, which can be rotated together with the spray arms 40, 42 about the rotation axis 32.

By means of the cleaning nozzles 44, 46, a liquid jet can be directed onto a surface 11 to be cleaned in order to clean the surface 11. To clean the surface 11, the surface cleaning head 10 can be moved along the surface 11, wherein it can be supported on the surface 11 by means of the splash guard element 20.

The cleaning nozzles 44, 46 generate a liquid jet directed diagonally downwards. For this purpose, they are aligned diagonally to the vertical in the horizontal position of use of the surface cleaning head 10 shown. This is particularly clear from Figure 3. When exiting the cleaning nozzles 44, 46, the liquid jets directed diagonally downwards generate a recoil that exerts a torque on the spray arms 40, 42 and thereby causes them to rotate about the axis of rotation 32.

In order to increase the cleaning performance, an oscillation device 50 is integrated into each of the cleaning nozzles 44, 46 to generate spatial oscillations of the liquid jets emitted by the cleaning nozzles 44, 46 in the form of a pendulum movement, which is superimposed on the circular movement of the liquid jets about the axis of rotation 32 and is illustrated in Figures 1 and 2 by a dashed line 52. The spatial oscillations provoke a disintegration of the liquid jets emerging from the cleaning nozzles 44, 46, so that the liquid jets at least partially dissolve into individual liquid droplets at a short distance from the cleaning nozzles 44, 46. Due to the water hammer effect, the individual droplets hit the surface 11 to be cleaned with high impact force, so that the surface 11 to be cleaned can be cleaned with high cleaning performance. The high cleaning performance allows the surface cleaning head 10 to be guided at a relatively high speed along the surface 11 to be cleaned, whereby even stubborn dirt, such as lichen, can be removed from the surface to be cleaned without complex subsequent cleaning. 11 can be removed. The high cleaning performance also makes it possible to save cleaning fluid and energy while maintaining the same cleaning performance compared to conventional surface cleaning heads.

The cleaning nozzles 44, 46 are identically designed and each have an oscillation device 50, which is shown enlarged in Figure 2 using the example of the cleaning nozzle 44. The cleaning nozzle 44 has a through-channel 54 that extends from a nozzle inlet 56 facing the spray arm 40 to a nozzle outlet 58 facing away from the spray arm 40. The oscillation device 50 forms a flow chamber 60 in the through-channel 54, in which a flow guide element 62 is arranged. The flow guide element 62 divides the flow chamber 60 into a central flow channel 64 and two opposing feedback channels 66, 68 that connect an output section 70 of the central flow channel 64 to an input section 72 of the central flow channel 64. The central flow channel 64 has, downstream of the inlet section 72, a first section 74 which is lens-shaped in a longitudinal section and a second section 76 which is lens-shaped in the longitudinal section and which is immediately adjacent to this, with a flow separation edge 78 being arranged between the first lens-shaped section 74 and the second lens-shaped section 76 and the second lens-shaped section 76 forming the outlet section 70 of the central flow channel 74 from which the feedback channels 66, 68 originate. The first lens-shaped section 74 is longer than the second lens-shaped section 76. In the exemplary embodiment shown, the length of the first lens-shaped section 74 is approximately 1.5 times the length of the second lens-shaped section 76.

The cleaning fluid entering the passage channel 54 of the cleaning nozzle 44 can flow through the central flow channel 64, with a portion of the cleaning fluid being returned from the outlet section 70 to the inlet section 72 via the feedback channels 66, 68. The mouth areas of the feedback channels 66, 68 are located directly opposite each other, so that the liquid flows returned via the feedback channels 66, 68 meet in the inlet section 72 and, due to flow instabilities, stimulate the cleaning liquid flowing through the central flow channel 64 to lateral deflections which are directed in succession and in opposite directions. This results in a self-excited resonance oscillation forming in the central flow channel 64, so that the liquid jet emerging from the cleaning nozzle 44, in addition to its circular movement about the axis of rotation 32, carries out the aforementioned pendulum movement 52, under the effect of which the liquid jet disintegrates into individual drops. The individual drops hit the surface 11 to be cleaned. This leads to a so-called water hammer effect, which leads to an increased impact force of the cleaning liquid, which significantly increases the cleaning performance. The drops can be completely separated from each other or can still be connected to each other via narrow liquid bridges (liquid ligaments), so that the liquid jet forms a modulated or pulsed liquid flow.

The oscillation frequency of the liquid jets emitted by the cleaning nozzles 44, 46 is preferably at least 10 Hz, in particular 10 Hz to 3,000 Hz.

The rotational speed of the spray arms 40, 42 is preferably a maximum of 15,000 revolutions per minute, in particular 1,000 to 3,000 revolutions per minute, for example 1,500 to 2,000 revolutions per minute.

In Figures 4 and 5, a second advantageous embodiment of a surface cleaning head according to the invention is shown schematically, which is designated overall by the reference numeral 80. The surface cleaning head 80, like the advantageous embodiments of surface cleaning heads according to the invention explained below with reference to Figures 6 to 15, is designed largely identically to the surface cleaning head 10 shown in Figures 1, 2 and 3 and explained above. In the In Figures 4 and 5 and also in Figures 6 to 15, identical components are therefore given the same reference numerals as in Figures 1, 2 and 3, and with regard to these components, reference is made to the preceding explanations in order to avoid repetition.

The surface cleaning head 80 shown schematically in Figures 4 and 5 differs from the surface cleaning head 10 shown schematically in Figures 1 and 2 in that the alignment of the cleaning nozzles 44, 46 is adjustable relative to the surface 11 to be cleaned. For this purpose, the surface cleaning head 80 has two diametrically opposed spray arms 82, 84, which each have an inner spray arm section 86 or 88 and an outer spray arm section 90 or 92 with respect to the rotation axis 32. The inner spray arm sections 86, 88 each have a first ring flange 94 or 96, and the outer spray arm sections 90, 92 each have a second ring flange 98, 100, wherein a second ring flange 98, 100 can be releasably screwed to a first ring flange 94 or 96 with the interposition of a sealing ring (not shown in the drawing for the sake of clarity). The first ring flanges 94, 96, like the second ring flanges 98, 100, have a plurality of through holes 106, 108 arranged at a uniform angular distance from one another with respect to the longitudinal axes 102, 104 of the two spray arms 82, 84. This allows the outer spray arm sections 90, 92 to be screwed to the inner spray arm sections 86, 88 in a desired rotational position, with a through hole 106 of the first ring flanges 94, 96 aligned with a through hole 108 of the second ring flange 98, 100, so that a connecting screw can be passed through the mutually aligned through holes 106, 108. In this way, the outer spray arm sections 90, 92 can assume a desired rotational position with respect to the longitudinal axes 102, 104, and as a result, the cleaning nozzles 44, 46 can assume a desired orientation with respect to the surface 11 to be cleaned. The cleaning nozzles 44, 46 can have a smaller or a larger inclination to the vertical in the illustrated position of use of the surface cleaning head 80. The greater the inclination to the Vertical, the greater the horizontal directional component of the recoil which acts on the cleaning nozzles 44, 46 when the cleaning liquid is dispensed and which drives the spray arms 82, 84 to rotate about the rotation axis 32. By changing the rotational position of the outer spray arm sections 90, 92, the speed of the spray arms 40, 42 can thus be changed.

Figure 6 schematically shows a third advantageous embodiment of a surface cleaning head according to the invention, which is designated overall by the reference numeral 120 and differs from the surface cleaning head 80 shown in Figures 4 and 5 by spray arms 122, 124, the axis of rotation 126 of which is inclined to the vertical in the horizontal position of use shown. This has the consequence that the distances that the cleaning nozzles 44, 46 assume from the surface 11 to be cleaned change continuously during a circular movement of the spray arms 122, 124 about the axis of rotation 126. This in turn has the consequence that the distances of the drops formed due to the disintegration of the liquid jets change continuously during a circular movement of the spray arms 122, 124. As a result, the drops striking the surface 11 to be cleaned can have a different size and/or a different impact force and, over a shorter distance, can be at least partially connected to one another via narrow liquid bridges (liquid ligaments). This supports a high cleaning performance, for example on uneven surfaces.

In Figures 7 and 8, a fourth advantageous embodiment of a surface cleaning head according to the invention is shown schematically, which is designated overall by the reference numeral 140. The surface cleaning head 140 differs from the surface cleaning head 80 explained above by spray arms 142, 144, each of which has an additional nozzle 146, 148, which are arranged upstream of the cleaning nozzles 44, 46 and are aligned tangentially with respect to the direction of rotation of the spray arms 142, 144. A tangentially aligned A jet of liquid can be emitted which exerts a recoil on the respective spray arm 142, 144 in order to increase the speed of the spray arms 142, 144. The nozzle openings of the additional nozzles 146, 148 can be considerably smaller than the nozzle openings of the cleaning nozzles 44, 46 in order to keep the flow rate of the cleaning liquid emitted via the additional nozzles 146, 148 low.

The use of the additional nozzles 146, 148 makes it possible, in a structurally simple manner, to increase the speed of the spray arms 142, 144 rotating around the rotation axis 32. This in turn makes it possible to guide the surface cleaning head 140 at a relatively high speed along the surface 11 to be cleaned. Due to the high cleaning performance that can be achieved by means of the oscillation devices 50, the relatively high speed of the surface cleaning head 140 does not impair the cleaning result.

Figure 9 schematically shows a fifth advantageous embodiment of a surface cleaning head according to the invention, which is designated overall by the reference numeral 160. The surface cleaning head 160 has diametrically opposed spray arms 162, 164, which can be set in rotation about the axis of rotation 32 by means of an electric motor rotary drive 166. The rotary drive 166 comprises an electric motor 168, which is coupled to the connecting part 30 via a gear 170 and which is supplied with electrical energy by a rechargeable battery 172 and controlled by a control device 174. The battery 172 can be connected to an external charger via a charging socket 176.

Figure 10 schematically shows a sixth advantageous embodiment of a surface cleaning head according to the invention, which is designated overall by the reference numeral 190. The surface cleaning head 190 has two diametrically opposed spray arms 192, 194, which are connected in a rotationally fixed manner to a turbine wheel 196. The turbine wheel 196 can be supplied with the cleaning liquid that can be fed to the cleaning nozzles 44, 46. and is set in rotation by the cleaning liquid about the rotation axis 32 of the spray arms 192, 194. With such a design, it is not necessary for the cleaning nozzles 44, 46 to be inclined obliquely to the vertical in a horizontal position of use of the surface cleaning head 190 in order to ensure a rotational movement of the spray arms. The liquid jets emitted by the cleaning nozzles 44, 46 can thus be directed perpendicularly to the surface 48 to be cleaned.

Figure 11 schematically shows a seventh advantageous embodiment of a surface cleaning head according to the invention, which is designated overall by the reference numeral 200. The surface cleaning head 200 differs from the surface cleaning heads explained above by cleaning nozzles 202, 204, which are designed in a known manner, for example in the form of flat jet nozzles or point jet nozzles, and by spray arms 206, 208, which each have an oscillation device 212 at their free ends facing away from the axis of rotation 32, which is designed as a pulsation device 214 in the form of a resonator chamber 216. The resonator chambers 216 are each arranged immediately upstream of a cleaning nozzle 202, 204. The resonator chambers 216 each form a cylindrical cavity with an inlet opening 218 and an outlet opening 220. When the surface cleaning head 200 is in operation, the pressurized cleaning fluid flows through the resonator chamber 216. The inlet opening 218 is followed by a radially outward-facing step 222, at which the flow of the cleaning fluid separates, so that vortices are formed that move in the direction of flow within the resonator chamber 216, with a resonance oscillation forming in the resonator chamber 216 in the form of axially aligned pressure fluctuations of the cleaning fluid. The cleaning fluid emerging from the resonator chamber 216 thus exhibits temporal oscillations in the form of pressure fluctuations. This means that the liquid jets emitted by the cleaning nozzles 202, 204 at least partially break up into individual drops that impact with high impact force on the surface 11 to be cleaned. in order to clean them effectively, as already explained above.

As an alternative to arranging the resonator chambers 216 upstream of the cleaning nozzles 202, 204, the resonator chambers 216 can also be integrated into the cleaning nozzles 202, 204.

Figure 12 schematically shows an eighth advantageous embodiment of a surface cleaning head according to the invention, which is designated overall by the reference numeral 240. The surface cleaning head 240 has spray arms 242, 244, which, unlike the spray arms 206, 208 of the surface cleaning head 200 explained above, do not have any oscillation devices. Instead, the surface cleaning head 240 uses an oscillation device 246 in the form of a pulsation device 248, which is arranged upstream of the spray arms 242, 244 in the inlet channel 26 of the surface cleaning head 240. The pulsation device 248 has a piezoceramic part 250 which is arranged in a radial extension 252 of the inlet channel 26 in the form of an annular body and has a central passage channel 254 through which the cleaning liquid supplied to the surface cleaning head 240 can flow.

The piezoceramic part 250 is connected to an alternating voltage generator 258 via an electrical connecting line 256 and can be supplied with an alternating electrical voltage by the generator. The application of the alternating voltage results in the piezoceramic part 250 carrying out mechanical oscillations radially aligned with respect to the axis of rotation 32, so that the pressurized cleaning liquid provided to the surface cleaning head 240 is subjected to pressure pulses. The pressure pulses spread in the flow direction of the cleaning liquid and result in the liquid jets emitted by the cleaning nozzles 202, 204 disintegrating by forming individual drops, as already explained above. To supply energy to the AC generator 258, the surface cleaning head 240 has a rechargeable battery 260. The rechargeable battery 260 can be connected to an external charger via a charging socket 262.

Figure 13 schematically shows a ninth advantageous embodiment of a surface cleaning head according to the invention, which is designated overall by reference numeral 270. The surface cleaning head 270 differs from the surface cleaning head 120 explained above with reference to Figure 12 in that it has an oscillation device 272 in the form of a pulsation device 273 with a first piezoceramic part 274 and a second piezoceramic part 276. The first piezoceramic part 274 has a passage channel in which the second piezoceramic part 276 is arranged to form an annular gap 278. Pressurized cleaning fluid can flow through the annular gap 278 and is fed to the cleaning nozzles 202, 204. Both piezoceramic parts 274, 276 can be supplied with an alternating electrical voltage by the alternating voltage generator 258, under the effect of which the two piezoceramic parts 274, 276 carry out mechanical oscillations so that the cleaning liquid flowing through the annular gap 278 is subjected to pressure pulses. As already explained above, the pressure pulses cause a disintegration of the liquid jets emitted by the cleaning nozzles 202, 204 by forming drops that hit the surface 11 to be cleaned with high impact force, so that the cleaning performance is significantly increased.

Figure 14 shows a tenth advantageous embodiment of a surface cleaning head according to the invention, which is designated overall by the reference numeral 280. The surface cleaning head 280 has an oscillation device 282 in the form of a pulsation device 284, which has a cuboid-shaped or cylindrical piezoceramic part 286, which can be supplied with electrical alternating voltage by the alternating voltage generator 258 and is thereby excited to mechanical vibrations. The Piezoceramic part 286 has a pressure application surface 290 on a front side 288, via which the cleaning liquid that can be fed to the cleaning nozzles 202, 204 can be subjected to pressure pulses. For this purpose, the cleaning liquid is guided along the pressure application surface 290, with the piezoceramic part 286 being arranged in a one-sided radial extension 292 of the inlet channel 26.

Figure 15 schematically shows an eleventh advantageous embodiment of a surface cleaning head according to the invention, which is covered in its entirety with the reference gauge 300. The surface cleaning head 300 has an oscillation device 302 in the form of a pulsation device 304, which has a resonator chamber 306. The resonator chamber 306 forms a radial extension of the inlet channel 26, whereby the cleaning liquid that can be fed to the cleaning nozzles 202, 204 can flow through the resonator chamber 306. As already explained above using the example of the surface cleaning head 200 shown schematically in Figure 11, a resonant oscillation of the cleaning liquid forms in the resonator chamber 306, which applies pressure pulses to the cleaning liquid. Such resonator chambers are also referred to as Helmholtz resonators. The effect of applying pressure pulses to the cleaning fluid is that the liquid jets emitted by the cleaning nozzles 202, 204 disintegrate at a short distance from the cleaning nozzles 202, 204, whereby drops are formed which hit the surface 11 to be cleaned with high impact force and thereby significantly increase the cleaning performance, as already explained above.

Claims

PATENT CLAIMS Surface cleaning head for cleaning a surface (11), with a hood-shaped housing (12) which is open downwards in a horizontal position of use of the surface cleaning head (10; 80; 120; 140; 160; 190; 200; 240; 270; 280; 300), in which at least one spray arm (40, 42; 82, 84; 122, 124; 142, 144; 162, 164; 192, 194; 206, 208; 242, 244) with a cleaning nozzle (44, 46; 202, 204) is mounted so as to be rotatable about a rotation axis (32; 126), wherein the cleaning nozzle (44, 46; 202, 204) is pressurized standing cleaning liquid can be supplied and the cleaning nozzle (44, 46; 202, 204) together with the spray arm (40, 42; 82, 84; 122, 124; 142, 144; 162, 164; 192, 194; 206, 208; 242, 244) rotates about the axis of rotation (32; 126) to apply a liquid jet to the surface to be cleaned (11), characterized in that the surface cleaning head (10; 80; 120; 140; 160; 190; 200; 240; 270; 280; 300) has an oscillation device (50; 212; 246; 272; 282; 302) for generating temporal and/or spatial oscillations of the liquid jet emitted by the cleaning nozzle (44, 46; 202, 204). Surface cleaning head according to claim 1, characterized in that the oscillation frequency for a spatial oscillation of the liquid jet is at least 10 Hz. Surface cleaning head according to claim 1, characterized in that the oscillation frequency for a temporal oscillation of the liquid jet is 10 kHz to 30 kHz. Surface cleaning head according to claim 1, 2 or 3, characterized in that the rotational speed of the at least one spray arm (40, 42; 82, 84; 122, 124; 142, 144; 162, 164; 192, 194; 206, 208; 242, 244) is a maximum of 15,000 revolutions per minute. Surface cleaning head according to claim 1, characterized in that the oscillation frequency of the liquid jet is at least as high as the rotational speed of the at least one spray arm (40, 42; 82, 84; 122, 124; 142, 144; 162, 164; 192, 194; 206, 208; 242, 244). Surface cleaning head according to claim 5, characterized in that the oscillation frequency of the liquid jet is a multiple of the speed of the at least one spray arm (40, 42; 82, 84; 122, 124; 142, 144; 162, 164; 192, 194; 206, 208; 242, 244). Surface cleaning head according to one of the preceding claims, characterized in that the oscillation device (50) is integrated into the cleaning nozzle (44, 46). Surface cleaning head according to claim 7, characterized in that the cleaning nozzle (44, 46) has a through-channel (54) and the oscillation device (50) forms a flow chamber (60) in the through-channel (54), in which a flow guide element (62) is arranged for generating a spatial oscillation of the liquid jet emitted by the cleaning nozzle (44, 46). Surface cleaning head according to claim 8, characterized in that the flow guide element (62) divides the flow chamber (60) into a central flow channel (64) and two mutually opposite feedback channels (66, 68), the feedback channels (66, 68) connecting an output section (70) of the central flow channel (64) to an input section (72) of the central flow channel (64). Surface cleaning head according to one of claims 1 to 7, characterized in that the oscillation device (212; 246; 272; 282; 302) is designed as a pulsation device (214; 248; 273; 284; 304) for generating temporal oscillations in the form of pressure fluctuations of the liquid jet emitted by the at least one cleaning nozzle (202, 204). Surface cleaning head according to claim 10, characterized in that the cleaning liquid can be subjected to pressure pulses by means of the pulsation device (214; 248; 273; 284; 304). Surface cleaning head according to claim 11, characterized in that the pulsation device (214; 306) has a resonator chamber (216; 306) which forms a pressure resonator for subjecting the cleaning liquid to pressure pulses. Surface cleaning head according to claim 12, characterized in that the resonator chamber is integrated into the cleaning nozzle. Surface cleaning head according to claim 12, characterized in that the resonator chamber (216; 306) can be flowed through by the cleaning liquid that can be fed to the cleaning nozzle (202, 204). Surface cleaning head according to claim 12, characterized in that the resonator chamber (216) is arranged in the at least one spray arm (206, 208). Surface cleaning head according to claim 15, characterized in that the resonator chamber (216) is arranged immediately upstream of the cleaning nozzle (202, 204). Surface cleaning head according to claim 12, characterized in that the resonator chamber (306) is arranged upstream of the at least one spray arm (242, 244). Surface cleaning head according to claim 10 or 11, characterized in that the pulsation device (248; 273; 284) has at least one piezoceramic part (250; 274, 276; 286) which can be subjected to an alternating electrical voltage, wherein the cleaning liquid can be subjected to pressure pulses by the at least one piezoceramic part (250; 274, 276; 286). Surface cleaning head according to claim 18, characterized in that at least one piezoceramic part (250) has a passage channel (254) through which the cleaning liquid can flow. Surface cleaning head according to claim 18, characterized in that the pulsation device (273) has a first and a second piezoceramic part (274, 276), the first piezoceramic part (274) having a passage channel in which the second piezoceramic part (276) is arranged to form an annular gap (278) through which the cleaning liquid can flow. Surface cleaning head according to claim 18, characterized in that at least one piezoceramic part (286) is cuboid-shaped or cylindrical and has a pressure application surface (290) on one end face (288) for applying pressure pulses to the cleaning liquid. Surface cleaning head according to one of claims 18 to 21, characterized in that the surface cleaning head (240; 270; 280) has a battery-operated alternating voltage generator (258) for applying an electrical alternating voltage to the at least one piezoceramic part (250; 274, 276; 286). Surface cleaning head according to one of claims 10 to 12 or 18 to 22, characterized in that the surface cleaning head (240; 270; 280; 300) has an inlet channel (26) for the pressurized cleaning liquid upstream of the at least one spray arm (242, 244), wherein the cleaning liquid can be subjected to pressure pulses in the region of the inlet channel (26) by means of the pulsation device (248; 273; 284; 304). Surface cleaning head according to one of the preceding claims, characterized in that the orientation of the at least one cleaning nozzle (44, 46) in the direction of the surface (11) to be cleaned is adjustable. Surface cleaning head according to claim 24, characterized in that the at least one spray arm (82, 84) has an inner and an outer spray arm section (86, 88; 90, 92) with respect to the rotation axis (32), wherein a cleaning nozzle (44, 46) is held on the outer spray arm section (90, 92) and the outer spray arm section (90, 92) can be detachably connected to the inner spray arm section (86, 88) in different rotational positions with respect to the longitudinal axis (102, 104) of the spray arm (82, 84). Surface cleaning head according to one of the preceding claims, characterized in that an additional nozzle (146, 148) for dispensing cleaning fluid is arranged on the at least one spray arm (142, 144), which is tangentially aligned with respect to the direction of rotation of the at least one spray arm (142, 144). Surface cleaning head according to one of the preceding claims, characterized in that the surface cleaning head (190) has a rotationally fixedly connected to the at least one spray arm (192, 194) Turbine wheel (196) which can be acted upon by the cleaning liquid that can be fed to the cleaning nozzle (44, 46). Surface cleaning head according to one of claims 1 to 26, characterized in that the surface cleaning head (160) has a motorized rotary drive (166), wherein the at least one spray arm (162, 164) can be set in rotation about the axis of rotation (32) by means of the rotary drive (166). Surface cleaning head according to one of the preceding claims, characterized in that the axis of rotation (126) of the at least one spray arm (122, 124) is inclined to the vertical in a horizontal position of use of the surface cleaning head (120).