CLEANING HEAD AND HARD SURFACE CLEANING DEVICE WITH ONE CLEANING HEAD

Description

[0001] The invention relates to a cleaning head for a hard surface cleaning device, in particular a floor cleaning device, wherein the cleaning head has at least one cleaning roller rotatable about an axis of rotation, which is held non-rotatably on a drive shaft which can be driven by rotation.

[0002] Furthermore, the invention relates to a hard surface cleaning device, in particular a floor cleaning device, with such a cleaning head and with a drive motor for driving the drive shaft of the cleaning head.

[0003] Hard surface cleaning machines, especially floor cleaning machines, often have a cleaning head for cleaning the hard surface, particularly a floor. The cleaning head comprises one or more cleaning rollers that are rotatable around a pivot axis and are fixed to a rotating drive shaft. The drive shaft is driven by a drive motor of the hard surface cleaning machine, with a gearbox often arranged between the drive motor and the drive shaft for torque transmission and speed reduction. The cleaning roller can, for example, be designed as a brush roller with a multitude of cleaning bristles. Alternatively, the cleaning roller can also have a cleaning surface, such as a cleaning fleece or cleaning fabric.

[0004] The drive shaft is often subjected to considerable mechanical stress due to high torsional and bending moments. Therefore, it is common practice to manufacture the drive shaft from metal, particularly steel. However, this requires several manufacturing steps and results in high production costs for the cleaning head. Furthermore, adapting the drive shaft's external geometry to different applications is a complex and costly process.

[0005] From DE 20 2018 004 148 U1, a cleaning head for a hard surface cleaning device is known. The cleaning head has a percussive cleaning roller that is rotated about a rotational axis by a drive. The percussive cleaning roller has a roller body that is fixed to a rigid shaft. The rigid shaft is preferably made of metal, and the roller body is preferably injection-molded onto the rigid shaft and is made, for example, of plastic. Several impact elements are provided on the outer surface of the roller body.

[0006] There are also cleaning heads known to have a drive shaft made of plastic. However, this reduces the mechanical strength of the drive shaft and therefore also of the entire cleaning head.

[0007] The object of the present invention is therefore to further develop a cleaning head of the type mentioned at the outset in such a way that it has high mechanical strength and yet low manufacturing costs.

[0008] This problem is solved in a cleaning head of the generic type according to the invention by the fact that the drive shaft has at least one inner shaft part made of metal, which is surrounded by an outer shaft part made of a plastic material.

[0009] The cleaning head according to the invention is characterized by high mechanical strength and lower manufacturing costs, since the drive shaft can be manufactured cost-effectively and yet withstands high torsional and bending torques. For this purpose, the drive shaft has at least one inner shaft section made of metal, which is surrounded by an outer shaft section made of a plastic material. The at least one inner shaft section ensures high mechanical strength of the drive shaft, and the outer shaft section made of plastic material allows for cost-effective adaptation of the drive shaft's outer geometry to different applications.

[0010] It is advantageous if the outer shaft part is a molded plastic component that is integrally formed with at least one inner shaft part. This integral forming of the outer shaft part with at least one inner shaft part enables a considerable reduction in manufacturing costs.

[0011] It may be provided that the drive shaft has several inner shaft parts made of metal, which are aligned coaxially to the axis of rotation of the drive shaft and surrounded by the outer shaft part.

[0012] The internal shaft components can be connected to each other in pairs, in particular screwed together.

[0013] It may also be provided that the inner shaft parts are loosely arranged next to each other or spaced apart from each other.

[0014] In a particularly preferred embodiment of the invention, the drive shaft has a single inner shaft part made of metal, which is embedded in the outer shaft part made of plastic.

[0015] It is advantageous if the single inner shaft part is surrounded by the outer shaft part made of plastic both over its entire circumference and at its end faces.

[0016] The at least one inner shaft part is preferably cylindrical in design.

[0017] Alternatively, at least one inner part of the shaft can be designed as a polygon, in particular as a square or hexagon.

[0018] It may be provided that at least one inner shaft part is designed as a solid body or in the form of a tube.

[0019] It is advantageous if the inner part of the shaft has knurling and / or indentations and / or steps, as this makes it easy to secure the inner part of the shaft against movement relative to the outer part.

[0020] In a preferred embodiment of the invention, the outer shaft part has at least one recess and / or at least one step on its outer surface. Preferably, the at least one recess is pocket-shaped.

[0021] It is advantageous if the volume of at least one inner shaft part is at least 5% to a maximum of 95% of the total volume of the drive shaft.

[0022] The cross-sectional area of ​​the at least one inner shaft part preferably amounts to at least 5% to a maximum of 95% of the cross-sectional area of ​​the drive shaft over its entire length.

[0023] In a preferred embodiment of the invention, the cleaning head has a gear unit for coupling the drive shaft to a drive motor, wherein the outer shaft section has a mounting section with increased material thickness for rotationally fixed attachment of a gear element of the gear unit. It is advantageous if the outer shaft section has its largest diameter in the area of ​​the mounting section.

[0024] The fastening section can, for example, form an end section of the outer shaft part or, for example, a middle section of the outer shaft part.

[0025] It is advantageous if the outer part of the shaft has at least one flat surface in the area of ​​the mounting section, as this facilitates the rotationally fixed attachment of the gear element to the mounting section.

[0026] Preferably, the gear element is positively connected to the mounting section of the outer shaft part.

[0027] The transmission device preferably comprises a transmission housing in which the drive shaft is rotatably mounted. The transmission housing accommodates at least the transmission element, which is non-rotatably connected to the outer part of the shaft, and allows the drive shaft to be rotatably mounted.

[0028] It is advantageous if the drive shaft passes through at least one through-opening of the gearbox housing, with the outer shaft section carrying a sleeve at the level of the through-opening. A sealing element, circumferentially surrounding the drive shaft, abuts the gearbox housing on the outer surface of this sleeve. The gearbox housing may be filled with oil. To prevent oil from escaping through the through-opening, the gearbox housing, in this embodiment of the invention, can be sealed by means of a sealing element that abuts the gearbox housing on one side and the outer surface of the sleeve surrounding the shaft section on the other. The outer surface of the sleeve forms a sealing surface. This ensures that the sealing element is not affected by the plastic material of the shaft section.For example, the outer part of the shaft may be made of a fiber-reinforced plastic material, with the use of the sleeve ensuring that the fibers of the plastic material do not damage the sealing element.

[0029] The sealing element arranged between the sleeve and the gearbox housing can, for example, be designed in the form of a shaft seal, in particular in the form of a radial shaft seal.

[0030] The sleeve is preferably pressed onto the outer part of the shaft.

[0031] The sleeve can be made of metal, for example.

[0032] It is advantageous if an additional sealing element, such as a sealing ring, is arranged between the sleeve and the outer shaft part. With such a design, the inside of the sleeve also forms a sealing surface.

[0033] In an advantageous embodiment of the invention, the cleaning head has two cleaning rollers rotatable about the axis of rotation, the gear unit being arranged between the cleaning rollers, and the drive shaft extending through the gear housing and carrying a cleaning roller on each of its longitudinal sections projecting from the gear housing. The aligned cleaning rollers can be driven to rotate about the common axis of rotation by means of the drive shaft, which can be coupled to a drive motor via the gear unit.

[0034] It is advantageous if the at least one cleaning roller has a roller body and a fixing device, wherein the roller body has a cleaning coating and / or a plurality of cleaning bristles on its outside and can be detachably fixed to the drive shaft by means of the fixing device.

[0035] The roller body can be designed as a single piece or in multiple parts. For example, it may be designed to be composed of several individual segments.

[0036] Preferably, the fixing device can be detachably connected to an axial extension of the drive shaft.

[0037] It is advantageous if the outer part of the shaft forms the axial extension.

[0038] For example, the roller body can be mounted axially onto a longitudinal section of the drive shaft projecting from the gearbox housing and detachably fixed to the drive shaft by means of the fixing device. The fixing device interacts with an axial extension of the drive shaft.

[0039] For example, it may be provided that the fixing device can be screwed to the extension of the drive shaft.

[0040] As mentioned at the outset, the invention also relates to a hard surface cleaning device, in particular a floor cleaning device. The hard surface cleaning device according to the invention comprises a cleaning head of the type mentioned above and a drive motor for driving the drive shaft of the cleaning head.

[0041] The hard surface cleaning device according to the invention is preferably designed as a hand-held hard surface cleaning device, in particular as a handle device.

[0042] Preferably, in addition to the cleaning head, the hard surface cleaning device has at least one spray nozzle through which a cleaning fluid can be applied to a hard surface to be cleaned, in particular a floor surface. The pressurized cleaning fluid can be supplied to the hard surface cleaning device, for example, by a water supply network or by a pump.

[0043] It is advantageous if the hard surface cleaning device has a rechargeable battery to power the drive motor.

[0044] The following description of an advantageous embodiment of the invention, in conjunction with the drawing, serves for further explanation. The drawing shows: Figure 1: a perspective view of a hard surface cleaning device having a cleaning head; Figure 2: a sectional view of the cleaning head along line 2-2 in Figure 1 Figure 3: a sectional view of the cleaning head along line 3-3 in Figure 2 , with two cleaning rollers of the cleaning head hidden; Figure 4: a sectional view of the cleaning head along line 4-4 in Figure 3 Figure 5: a perspective view of a drive shaft of the cleaning head; Figure 6: a partially cutaway view of the drive shaft made of Figure 5 .

[0045] In Figure 1An advantageous embodiment of a hard surface cleaning device according to the invention is shown schematically by way of example, which is designated overall by reference numeral 10. The hard surface cleaning device 10 is designed in the form of a hand-held floor cleaning device 12, which can be guided manually by the user along a floor surface to be cleaned.

[0046] The floor cleaning device 12 has an advantageous embodiment of a cleaning head 14 according to the invention, which is located in the Figures 2 to 6 is shown schematically.

[0047] The floor cleaning device 12 comprises a body 16, which has a housing 18 and is connected via a handle 20 to a control unit 22 of the floor cleaning device 12. The control unit 22 has a pistol-grip handle 24, which can be gripped by the user with one hand. A connection element 26 is arranged on the control unit 22, which is connected via a fluid line (not shown in the drawing) to two spray nozzles 30, 32 arranged on the body 16. The fluid line passes through the handle 20. A water hose (not shown in the drawing for clarity) can be connected to the connection element 26. Water can be supplied to the floor cleaning device 12 from a water supply network or a pump via the water hose and applied to the floor surface to be cleaned via the spray nozzles 30, 32.

[0048] The cleaning head 14 is held on the device body 16. It has a drive shaft 34 which is coupled via a gear unit 36 ​​to an electric drive motor 38 located in the housing 18 of the device body 16. The drive motor rotates the drive shaft 34 about a pivot axis 40. A rechargeable battery 42 is detachably mounted on the control unit 22 to supply the drive motor 38 with electrical energy. This battery is electrically connected to the drive motor 38 via an electrical cable (not shown in the drawing). The electrical cable passes through the handle 20. An electrical switch with a lever 39, which can be operated by the user, is located on the handle 24 of the control unit 22 to switch the drive motor 38 on and off.

[0049] Alternatively or additionally to the rechargeable battery 42, a supply cable can be provided via which the floor cleaning device 12 can be connected to a power supply network.

[0050] The drive shaft 34 has an inner shaft part 44 made of metal, preferably steel. The drive shaft 34 also has an outer shaft part 46 made of a plastic material, in particular a fiber-reinforced plastic material, which surrounds the inner shaft part 44. The outer shaft part 46 is a molded plastic part, in particular an injection-molded part, which is integrally formed with the inner shaft part 44.

[0051] As is particularly evident from Figure 6As is clearly evident, the inner shaft part 44 is cylindrical and has a constant diameter along its entire length. However, it is also possible for the inner shaft part 44 to have projections, recesses, and / or steps. Alternatively, the inner shaft part 44 can also be designed as a polygon.

[0052] The outer part of the shaft 46 forms a mantle 48 which surrounds the inner part of the shaft 44 in the circumferential direction and which has several depressions 49 as well as projections 50 and steps 51 on its outer side.

[0053] With its end sections, the outer shaft part 46 forms a first extension 52 and a second extension 54, which are axially aligned. The extensions 52 and 54 are integrally connected to the shell 48 and cover the end faces 56, 58 of the inner shaft part 44. The first extension 52 forms a first external thread 60 and the second extension 54 forms a second external thread 62.

[0054] The outer shaft section 46 has a fastening section 64 with increased material thickness located longitudinally in the center. This fastening section forms two opposing flats 66, 68. The outer shaft section 46 has its largest diameter in the area of ​​the fastening section 64, which decreases in steps towards the extensions 52, 54.

[0055] The transmission device 36 has a transmission housing 70 through which the drive shaft 34 passes. For this purpose, the transmission housing 70 has a first through-opening 72 and a second through-opening 74. At the level of the through-openings 72 and 74, the drive shaft 34 carries a sleeve 76 and 78, respectively, the sleeves 76 and 78 being pressed onto the outer shaft part 46 and thus rotationally fixed to the outer shaft part. Preferably, the sleeves 76 and 78 are made of metal. A sealing ring 80 and 82, respectively, is arranged between the sleeves 76 and 78 and the outer shaft part 46 to seal the respective sleeve 76 and 78 against the outer shaft part 46. Between the sleeves 76, 78 and the gearbox housing 70, a sealing element in the form of a radial shaft seal 84 or 86 is arranged to seal the drive shaft 34 against the gearbox housing 70.The sleeves 76 and 78 each form a sealing surface with their outer surfaces, against which the radial shaft seals 84 and 86 bear in sealing contact even when the drive shaft 34 is rotating. The sleeves 76 and 78 ensure that the radial shaft seals 84 and 86 are not affected by the fiber-reinforced plastic material of the shaft outer part 46, even when the drive shaft 34 is rotating.

[0056] The drive shaft 34 is rotatably mounted on the gearbox housing 70 by means of a first bearing 88 and a second bearing 90.

[0057] The transmission assembly 36 forms a worm gear 92, via which the drive shaft 34 is coupled to a motor shaft 94 of the drive motor 38. The worm gear 92 has a worm wheel 96, which is held non-rotatably on the mounting section 64 between the first bearing 88 and the second bearing 90, with the worm wheel 96 being pressed onto the flats 66, 68.

[0058] The worm gear 96 is operatively connected to a worm shaft 98, which is rotationally fixed to the motor shaft 94. This is derived from Figure 4 clearly.

[0059] The drive shaft 34 has a first longitudinal section 100 and a second longitudinal section 102, which are opposite each other and each protrude from the gearbox housing 70. A first cleaning roller 104 is fixedly mounted on the first longitudinal section 100 and a second cleaning roller 106 is fixedly mounted on the second longitudinal section 102.

[0060] The first cleaning roller 104 has a first roller body 108 which has on its outside a first bristle covering 110 with a plurality of cleaning bristles 112. Similarly, the second cleaning roller 106 comprises a second roller body 114 which has on its outside a second bristle covering 116 with a plurality of cleaning bristles 118.

[0061] The roller bodies 108, 114 can be designed as one piece or as multiple pieces. In particular, the roller bodies 108, 114 can be composed of several individual segments.

[0062] For axial fixation of the first cleaning roller 104 to the drive shaft 34, the first cleaning roller 104 has a first fixing device 120. The first fixing device 120 comprises a first fixing element 122, which can be inserted axially into a recess 124 of the first roller body 108 and screwed to the first extension 52 of the shaft outer part 26, which projects into the recess 124. At its end facing away from the first extension 52, the first fixing element 122 carries a first fixing flange 126 projecting from the recess 124, which bears against the end face 128 of the first roller body 108 facing away from the gearbox housing 70.

[0063] For axial fixation of the second cleaning roller 106 to the drive shaft 34, the second cleaning roller 106 has a second fixing device 130. The second fixing device 130 comprises a second fixing body 132, which can be inserted axially into a recess 134 of the second roller body 114 and screwed to the second extension 54 of the shaft outer part 46, which projects into the recess 134. At its end facing away from the second extension 54, the second fixing body 132 carries a second fixing flange 136, which bears against the end face 138 of the second roller body 114 facing away from the gearbox housing 70.

[0064] The two cleaning rollers 104, 106 are detachably held on the drive shaft 34. To detach the first cleaning roller 104 from the drive shaft 34, the first fixing element 122 can be unscrewed from the first extension 52, so that the first roller body 108 can then be pulled off the first longitudinal section 100 of the drive shaft 34. Similarly, the second fixing element 132 can be unscrewed from the second extension 54, so that the second roller body 114 can then be pulled off the second longitudinal section 102 of the drive shaft 34.

Claims

1. Cleaning head for a hard surface cleaning appliance, wherein the cleaning head (14) comprises at least one cleaning roller (104, 106), which is rotatable about a rotational axis (40) and is held on a rotationally drivable drive shaft (34) in a rotationally-fixed manner, wherein the drive shaft (34) comprises at least one shaft inner part (44) consisting of metal, characterized in that the shaft inner part (44) is surrounded by a shaft outer part (46) consisting of a plastic material.

2. Cleaning head in accordance with Claim 1, characterized in that the shaft outer part (46) forms a plastic molded part, which is molded onto the at least one shaft inner part (44).

3. Cleaning head in accordance with Claim 1 or 2, characterized in that the drive shaft (34) comprises one single shaft inner part (44), which is embedded into the shaft outer part (46).

4. Cleaning head in accordance with Claim 1, 2, or 3, characterized in that the at least one shaft inner part (44) is of cylindrical configuration or is configured as a polygon.

5. Cleaning head in accordance with any one of the preceding Claims, characterized in that the shaft outer part (46) comprises recesses (49) and / or projections (50) and / or steps (51) on its outer side.

6. Cleaning head in accordance with any one of the preceding Claims, characterized in that the cleaning head (14) comprises a transmission device (36) for coupling the drive shaft (34) to a drive motor (38), wherein the shaft outer part (46) comprises a fastening portion (64) with an increased material thickness for fastening a transmission element (96) of the transmission device (36) in a rotationally-fixed manner.

7. Cleaning head in accordance with Claim 6, characterized in that the transmission device (36) comprises a transmission housing (70), on which the drive shaft (34) is rotatably mounted.

8. Cleaning head in accordance with Claim 7, characterized in that the drive shaft (34) passes through at least one through-opening (72, 74) of the transmission housing (70), wherein the shaft outer part (46) bears at the level of the through-opening (72, 74) a sleeve (76, 78), against the outer side of which a sealing element (84, 86) surrounding the drive shaft (34) in the circumferential direction sealingly abuts for sealing the transmission housing (70).

9. Cleaning head in accordance with Claim 8, characterized in that a sealing ring (80, 82) is arranged between the sleeve (76, 78) and the shaft outer part (46).

10. Cleaning head in accordance with any one of Claims 6 to 9, characterized in that the cleaning head (14) comprises two cleaning rollers (104, 106), which are rotatable about the rotational axis (40), wherein the transmission device (36) is arranged between the cleaning rollers (104, 106), and wherein the drive shaft (34) passes through the transmission housing (70) and bears a respective cleaning roller (104, 106) on each of its longitudinal portions (100, 102) projecting out of the transmission housing (70).

11. Cleaning head in accordance with any one of the preceding Claims, characterized in that the at least one cleaning roller (104, 106) comprises a roller body (108, 114) and a fixing device (120, 130), wherein the roller body (108, 114) bears on its outer side a cleaning covering and / or a multitude of cleaning bristles (112, 118) and is releasably fixable to the drive shaft (34) by means of the fixing device (120, 130).

12. Cleaning head in accordance with Claim 11, characterized in that the fixing device (120, 130) is releasably connectable to an axial extension (52, 54) of the drive shaft (34).

13. Cleaning head in accordance with Claim 12, characterized in that the shaft outer part (46) forms the axial extension (52, 54).

14. Hard surface cleaning appliance comprising a cleaning head (14) in accordance with any one of the preceding Claims and comprising a drive motor (38) for driving the drive shaft (34) of the cleaning head (14).