Handheld portable cutting device

Abstract

Working unit, preferably mountable on a hand-operated cleaning and maintenance device, designed with a cutting device (1), in particular for cutting grass blades of a lawn, a drive shaft (2) arranged laterally behind the cutting device (1) parallel to a cutting axis of the cutting device (1) characterized in that the drive shaft (2) is connected to the cutting device via a gearbox, preferably a bevel gear gearbox (14), in particular a 90° bevel gear gearbox, such that a rotary movement of the drive shaft (2) is converted into an oscillating, in particular translational movement of the upper blade (18) and lower blade (19).

Description

[0001] The invention relates to a drive unit, which is preferably connectable to a hand-operated cleaning and maintenance device, wherein the drive unit comprises a cutting device and a hand-operated cleaning and maintenance device with a cutting device.

[0002] The cutting device is a cutting device such as those used for mowing grass. Cutting devices operating on the scissor principle, used as mowing devices, can be divided, according to the current state of the art, into sickle bar mowers and grass shears.

[0003] Sickle bar mowers have translationally oscillating blades. In contrast, the blades of grass shears oscillate around a pivot point.

[0004] A rotary oscillating system is shown, for example, in US 3,623,223 A. The system shown in US 3,623,223 A consists of a stationary lower blade and a rotary oscillating upper blade. The upper blade is driven by an eccentric disc, which is preferably directly connected to the electric motor via a shaft.

[0005] Sickle bar mowers are predominantly used in agriculture for larger cutting widths. The sickle bar mower known from EP 2853142 A1 has cutter bars guided on both sides. A hand-operated, portable sickle bar mower with a cutter bar guided on one side is shown in WO 1999 / 07202 A1. These cutter bars of sickle bar mowers have cutting widths from approximately 500 mm to several meters.

[0006] As an alternative to sickle bar mowers, grass shears can also be used for cutting grass. The advantage of grass shears is their simple design. However, a disadvantage is their limited cutting width, making them suitable only for narrow strips of grass that cannot be reached by standard lawnmowers and are therefore left uncut. Larger cutting widths with grass shears can only be achieved, as shown in EP 1886551 A1, by placing several shear blades, for example two, side by side.

[0007] US Patent 2,702,978 A discloses a drive unit mountable to a hand-operated cleaning and maintenance device. While the drive is located behind the cutting unit in the cutting direction, the motor-driven drive shaft is symmetrically mounted in the center of the cutting bar. According to US Patent 2,702,978 A, the motor is mounted in the handle area and the drive shaft is mounted in the handlebar. The feed force applied by the user, who moves the device in the cutting direction and thus in the direction of travel, distributes the force equally between the left and right wheels. If the drive were mounted off-center, this would cause the device to tend to move in a circular path in the direction of travel. Therefore, in US Patent 2,702,978 A, the drive shaft and the drive are positioned centrally. Furthermore, in US Patent 2,702,978 A, only the upper blade is set in motion by an oscillating lever, whereas the lower blade is stationary.In US Patent 2,702,978 A, an adjusting screw (48) in the front cutting area of ​​the upper blade (49) pre-tensions a spring to apply pre-tension, which then exerts a force on the oscillating upper blade. This arrangement has the disadvantage of being located in an area susceptible to dirt. Furthermore, a pre-tension is applied against the housing. This has the disadvantage that all housing components must be very rigidly connected to the lower blade in order to achieve the pre-tension against the lower blade.

[0008] German patent DE 38 212 35 A1 discloses a two-wheeled, motor-driven mowing device that the user pushes in front of them using wheelbarrow-like handles. To drive the two cutting blades, which oscillate in opposite directions, DE 38 212 35 A1 has a central drive shaft for each of the two cutting blades, just like US patent US 2,702,978 A.

[0009] DE 10 2005 049 665 A1 discloses a cutting device with an interchangeable knife arrangement, which comprises two oscillating knives that can be moved relative to each other.

[0010] The KR 20 2000 0004 4787 U shows a grass cutter with two blades that are driven together via a 90° bevel gear drive.

[0011] In recent years, robotic lawnmowers have become particularly popular in small gardens. These robotic mowers autonomously navigate a defined area to cut the grass, following random or specific patterns. However, along the edges, especially along walls or house fronts, a strip of grass at least 200 mm wide typically remains uncut. These strips are too wide for lawn edging shears to be used effectively. Therefore, cutting such an area with lawn shears requires several passes.

[0012] The object of the invention is therefore to avoid the disadvantages of the prior art and, in particular, to provide a system that is characterized by allowing the cutting of the edge area of ​​grass blades in front of walls or house fronts. Furthermore, a system is to be provided that includes a cutting device, wherein the cutting device can be easily exchanged for other inserts or tools and is driven by a universal motor with gearbox, in particular a hand-held cleaning and maintenance device.

[0013] A further object of the present invention is to provide a clean cut even of the blades of grass in a lawn. Generally, a meadow consists of grass blades that are to be cut. The grass blades of a meadow, in turn, comprise grass stalks and grass leaves. The prior art mowing devices with cutter bars are not suitable for cutting grass leaves in a lawn, but only for cutting grass stalks in a meadow, or for mowing a meadow. Both grass stalks and grass leaves can generally be referred to as grass blades.

[0014] One difference between a meadow and a lawn is that lawns require regular mowing. The height of a lawn is generally between 1 cm and 10 cm. Meadows, on the other hand, have a minimum height of 10 cm, with individual stems that can grow up to 80 cm tall. While lawns consist of leaves, meadows consist of stems or stalks. Stems or stalks are flowering shoots, tubular in structure, and possess high bending strength. Due to their tubular shape, stems are rigid in cross-section and do not break even in strong winds.

[0015] A lawn, on the other hand, consists only of leaves. Regular mowing at short intervals prevents the development of flowering shoots and therefore stems. A lawn leaf, much like a pair of hand scissors, must be cut with sharp, tensioned blades. If the blade is dull or the tension is insufficient, the blade will bend over instead of cutting the leaf.

[0016] In contrast, a fully grown stem, due to its high bending stiffness, is always sheared off and thus cut by knife blades.

[0017] However, if the tension is insufficient, the blades of grass in a meadow are not cut, but merely bent over and / or torn off.

[0018] The prior art, as described in DE 38 212 35 A1, is limited to a simple lawnmower that cuts grass stems or blades due to insufficient preload; a precise cut of grass with blades is not possible with such an arrangement. The struts described in DE 38 212 35 A1 are pressed against each other at the pivot point to ensure the blades lie flat. However, this does not constitute a preload on the blades according to the invention, as is the case with the invention itself.

[0019] In DE 38 212 35 A1, the blades are held together in the cutting area by clamps. Sliding linings ensure that the blades lie flat against each other. This prevents any preload.

[0020] According to the invention, the problem of the invention is solved by a working unit according to claim 1.

[0021] Further developments of the invention are the subject of dependent claims.

[0022] The drive unit according to claim 1 is characterized in that it can be easily mounted on a hand-held cleaning and maintenance device and can be replaced, for example, by a roller.

[0023] In addition to the working unit, the invention also provides a cleaning and maintenance device with a drive unit and cutting device according to the invention.

[0024] The cutting device of the drive unit of the invention preferably comprises cutter bars that enable the cutting of grass blades in areas close to edges. According to the invention, the drive is preferably provided by two opposing eccentric discs, similar to hedge trimmers. In contrast to hedge trimmers, where the drive is always located in the axis of the blade, the drive of the cutting device according to the invention is provided parallel to the cutting axis by means of eccentric discs. In order to utilize the entire blade width, it is advantageously provided that the drive is arranged behind the cutter bar. In contrast to, for example, US 2,702,978 A, the drive located behind the cutting device comprises, for example, a motor positioned transversely in the direction of travel, which rotates the drive shaft parallel to the cutting axis. Such an arrangement allows for cutting close to edges on both sides of the cutter bar.Preferably, the motor is arranged centrally and parallel to the cutting axis. This ensures that, for improved handling of a hand-held cleaning and maintenance device equipped with an arrangement according to the invention, it includes a low-mounted motor, which facilitates better handling of the cleaning and maintenance device and the drive unit. Furthermore, the low-mounted motor does not obstruct the operator's view of the blades during the cutting process. To drive the cutting device with the drive located behind the cutting device, for example, the cutting blade, which comprises a transversely mounted motor, the drive shaft is connected to a vertical drive axis of the working unit via a bevel gear. Preferably, the working unit with cutting device according to the invention can be connected to a cleaning and maintenance device as known from DE 10 2014 010 692 A1.The user-friendly, tool-free assembly of the work unit with cutting device is particularly advantageous. In particular, the motor of the cleaning and maintenance equipment, for example, can be used to drive the work unit.

[0025] The cleaning and maintenance device can be used for various purposes thanks to the working unit with cutting device. For example, the roller brush of the cleaning and maintenance device shown in DE 10 2014 010 692 A2, which is driven by an electric motor, for example via a belt drive, can preferably be exchanged without tools for a drive unit of the invention with a cutting device. The drive unit according to the invention with cutting device is then driven by the same electric motor as the roller brush of the cleaning and maintenance device of DE 10 2014 010 692 A2. This provides a hand-operated cleaning and maintenance device that can be used for very different purposes, for example, by simply exchanging the roller for the drive unit with cutting device according to the invention, thus creating a cutting device.Preferably, for easy replacement, the drive shaft of the cutting device, which is parallel to a cutting axis of the cutting device, is connected to the drive shaft of the electric motor via a gearbox, preferably a bevel gear drive. This allows for easy replacement of a cutting device and, for example, a roller brush driven by an electric motor of a cleaning and maintenance unit. With the aid of the bevel gear drive, the horizontal rotational energy introduced via the drive shaft of the electric motor of the cleaning and maintenance unit can be converted into a vertical movement, which in turn acts, for example, on two circular discs arranged eccentrically and offset by 180°, resulting in a translational movement of an upper and a lower blade of a cutting device.The conversion of the horizontal movement into a vertical movement, which drives the cutting device, is thus achieved by the bevel gear drive.

[0026] In a particularly preferred embodiment of the invention, the cutting device has a cutting width in the range of 100 mm to 500 mm. A cutting width of 350 mm is especially preferred. Such a cutting width ensures that grass can be cut and removed safely in the edge areas of the lawn strips. Furthermore, small meadows or lawns with leaves can also be mowed with such cutting widths. Lawn mowers for small gardens or allotments generally start with a cutting diameter of 280 mm. To reduce vibrations caused by translational oscillating movements, it is particularly advantageous if the cutting device has two counter-rotating cutting blades. When using two counter-rotating cutting blades, the vibration amplitude is halved compared to one oscillating and one stationary blade, and thus the vibrations are also significantly reduced.

[0027] A cutting device with two counter-rotating cutting blades preferably comprises an upper blade and a lower blade. Both the upper and lower blades have pointed cutting edges. These pointed cutting edges can easily bend under load, thus impairing the cutting result.

[0028] The disadvantage of the high elasticity of both the upper and lower blades can be used to advantage by pre-tensioning the upper blade. Pre-tensioning the upper blade allows for a better cutting result than with an unstrained blade. Like scissors, the blades always cut at the contact point between the upper and lower blades. Pre-tensioning creates a gap between the blades that decreases towards the cutting edge. The contact point of the cutting edges of the upper and lower blades is then under tension. This pre-tension ensures that the cutting edges remain in contact during operation. If the pre-tension is insufficient or absent, material such as grass blades cannot be cut.In such a case, the material being cut, such as a blade of grass, bends because the contact surfaces between the upper and lower blades are insufficient. The device according to the invention, due to its design, provides precisely the necessary preload to ensure that even blades of grass in a lawn are cut cleanly.

[0029] To generate the preload, one embodiment preferably incorporates an insert between the upper and lower blades. This insert ensures a sufficient distance between the blades to apply enough preload, for example, to the upper blade for a clean cut, with the preload decreasing towards the blade edge. Despite the preload, the elasticity of the blades reduces friction and thus the required motor power. The distance between the upper and lower blades, or the additional distance created by the insert, is 1–2 mm, ideally between 1.3 mm and 1.5 mm. The parallel spacing of the drive lugs, which also create a distance between the upper and lower blades and are found, for example, in hedge trimmers, ensuring a centric force transmission between the opposing eccentric discs, is approximately 3 mm.Spaced-apart upper and lower blades are initially not under tension. Therefore, while such an arrangement allows for cutting a hedge, it is not suitable for cutting grass, such as lawn blades, as the blades would simply snap off. As the inventor discovered, cutting grass is only possible when the blades, i.e., the upper and lower blades, glide very closely against each other. This close contact is crucial, especially for cutting grass blades. Sufficient tension is required for this, which is achieved in one embodiment by the additional space between the blades. Surprisingly, this sufficient tension ensures that the cutting edges of the upper and lower blades always remain in contact at the cutting surface, thus guaranteeing a clean cut, particularly for lawn blades.If the parallel spacing of the tabs, required for low-friction operation of the upper and lower blades, is 3 mm, and the additional spacing required for preload is 1.5 mm, then the total height of the insert is 3 mm plus 1.5 mm, or 4.5 mm. The eccentric discs for driving the upper and lower blades engage with the blade tabs.

[0030] The tabs can be positioned far from the center of the upper or lower blade. To ensure optimal preload, the distance from the center of the blade and / or clamping profile to the tab, which is specified in Fig. 5.2, shown and labeled a, is between 20 mm and 60 mm, ideally 48 mm in one embodiment. Ideally, the distance a' from the tip of the upper and lower blades to the center of the clamping profile, to which it is clamped with screws, corresponds approximately in a particular embodiment to the distance a from the center of the clamping profile to the insert or spacer. In this embodiment, the distance a' is, for example, 43 mm. Thus, the total distance a + a' from the tip of the upper and lower blades to the spacer used to apply the preload is in the range of 60 mm to 100 mm. The blades of the upper and lower blades have a thickness of 1–1.5 mm, ideally 1.15 mm. The tabs of the upper and lower blades are spaced 2–6 mm apart in the area of ​​the eccentrics, particularly 3 mm apart in the embodiment shown. Fig. 5.2, from each other, to ensure reliable force transmission from the eccentric discs to the tabs. The spacing of 2–6 mm between the tabs is achieved through design. A 3 mm spacing between the tabs prevents them from jumping onto the opposite eccentric. Generally, the tabs must be spaced apart to transmit force to the offset eccentrics.

[0031] To apply the necessary preload, the distance in the embodiment according to... Fig. 5.2 The height is increased again by approximately 1.5 mm by an additional gap, so that the total height of the insert placed between the blades is between 3.5 mm and 7.5 mm, preferably 4.5 mm, when the friction-reducing gap is 3 mm. If the tabs were not spaced apart by the 2 to 6 mm specified in the invention, but were, for example, directly on top of each other, there is a risk that the eccentric discs would jump out of the elongated guide slots of the blade tabs. To prevent the tabs from jumping out of the elongated guide slots, an intermediate disc made of hardened steel can also be provided, the outer diameter of which is large enough to largely cover both elongated slots.

[0032] If the blades were not pre-tensioned, they would lie so tightly against each other that very high friction would occur. With grass shears, unlike hedge shears, it is essential that the blade edges remain in contact. This is best achieved with a pre-tension that creates an additional gap of 1.5 mm on top of the 3 mm in the embodiment according to [reference to relevant figure]. Fig. 5.2 effect. In Fig. 5.3 is an alternative design for applying a preload relative to Fig. 5.2 shown. In the design according to Fig. 5.3 The knives rest on a stabilizing intermediate disc and are bent upwards due to the harder spring steel used, thus creating preload.

[0033] The pre-tensioning devices shown in the prior art, e.g., in DE 38 212 35 A1, are used with rotary oscillating blades, in contrast to the translational blades of the invention. The pre-tensioning of blade bars in the prior art is achieved by a plurality of clamping jaws that press the blades together in the front region. Applying pre-tensioning to the blade bars, as shown in the prior art, in the front region of the blades, e.g., in DE 38 212 35 A1, has the disadvantage of hindering grass removal. This impairs the cutting quality, and a clean cut of grass, e.g., blades of grass in a lawn, is not possible in the prior art; only the cutting of grass stalks, such as those found in a meadow, is possible. In contrast, the invention enables the cutting of grass blades from a lawn.The reason that, in prior art designs such as DE 38 212 35 A1, only grass stems can be cut and not grass leaves is that, with blades pre-tensioned in the front section, the material to be cut falls onto the upper blade behind the cutting edges and is then transported and deposited to the sides by the oscillating movement of the upper blade. Tensioning devices in the front section, as in the prior art, thus impede the lateral transport of the material to the sides. This is particularly evident in a prior art design according to US 2,702,978. In US 2,702,978, the grass is cut, pressed in the cutting direction by the upper blade (referred to as the "upper section" in US 2,702,978), and then falls forward into the grass to be cut. This significantly reduces the cutting quality.If, according to the invention, the preload is applied not in the front area of ​​the cutting blades, but in the rear area of ​​the upper and lower blades by means of a spacer element, e.g., at a distance of 60–100 mm from the blade tip, it is possible for the material to be cut not to fall forward, but to be discharged to the sides, in particular continuously, without impairing the cutting process and / or the cutting quality, thus enabling the cutting of grass, especially grass blades. Particularly good cutting results are achieved when the preloading device, in particular the inserts that provide the additional distance, is located 60 mm to 100 mm from the tips of the cutting blade.

[0034] If the preload is applied only in the area of ​​the tabs due to the additional spacing resulting from the increased use, the problem arises that, depending on the position of the tabs, the knives or blades would only lie close together in a partial area, i.e., only over a portion of the knife's length, while not lying close together over another portion. In a preferred embodiment of the invention, an additional tab is provided in another portion of the length, ensuring that this portion of the knife or blades also lie close together. The number of additional tabs is not limited but depends on the necessity. Thus, one, two, etc., additional tabs can be provided.

[0035] In order to keep the cutting device at a certain height relative to the grass to be cut, the working unit is designed to include height-adjustable wheels.

[0036] In order to capture grass even near edges, the drive unit according to the invention is equipped with a guiding device, for example in the form of sliding shoes and grass guides. The grass guide and the guiding device allow grass leaves and / or grass stems to be guided into the cutter bars and thus into the cutting area of ​​the cutting device.

[0037] Preferably, the vertical shaft acts on two eccentrically arranged circular discs offset by 180°, with the circular discs being encompassed by the vertical shaft in a preferred embodiment. This design allows the upper and lower blades to move in opposite directions. Compared to a single blade, the distances traveled by the blades are halved in such an embodiment for the same cutting width. Due to the shorter blades, the acceleration forces are significantly lower than with a very long single blade. Because the inertial forces of the blades are moving in opposite directions, they cancel each other out, resulting in vibration damping. This vibration damping, in turn, reduces the vibrations of the device to a minimum, thus significantly increasing user comfort.This is because a single blade generates vibrations that cause the entire device to vibrate laterally. However, when, as in the present case, two blades move in precisely opposite directions, the vibration amplitudes are approximately equal, with one amplitude being positive and the other negative, so that the forces cancel each other out and the vibration amplitudes are eliminated.

[0038] To ensure that the two blades, also referred to as upper and lower blades, deliver a good cutting result, they are arranged between a base plate and a clamping profile in a further developed embodiment. The distance between the base plate and the clamping profile is preferably determined by spacers, the height of which, or the distance between the base plate and the clamping profile, is selected such that the cutting edges of the blades are in contact, but the friction between the blades is low. This is particularly advantageous in the embodiment according to... Fig. Shown in 5.2 and 5.3.

[0039] To absorb the forces that occur when the cutting blades suddenly jam, a preferred embodiment provides that the drive unit's gearbox, which drives the blades, comprises two housings: an inner and an outer housing. The inner housing, for example, absorbs lateral forces generated by the eccentric discs and bevel gears when the blades jam. To convey material being cut away from the blades and to ensure visibility of the blades, a further embodiment provides that the cutting device includes a cover.

[0040] The invention will be described in more detail below with reference to the drawings.

[0041] They show: Fig. 1: a drive unit according to the invention with a cutting device and wheels Fig. 2: a hand-held cleaning and maintenance device equipped with a drive unit according to the invention with a cutting device Fig. 3: the gearbox unit with the input shaft, which can be connected to a hand-operated cleaning or maintenance device Fig. 4.1: Top view of a first embodiment of a cutting device with two cutting blades in the form of upper and lower blades Fig. 4.2: Top view of a second embodiment of a cutting device with two cutting blades, wherein the upper blade is pre-tensioned. Fig. 4.3: Top view of a third embodiment of a cutting device with two cutting blades and an additional tab for applying the preload Fig. 5.1: Section along line AA in Fig. 4.1 of the first embodiment of a cutting device with two cutting blades Fig. 5.2: Section along line AA in Fig. 4.2 of the second embodiment of a cutting device or cutting apparatus, wherein the upper blade is pre-tensioned. Fig. 5.3: Section along line AA in Fig. 4.2 of the second embodiment of a cutting device, wherein the upper blade is pre-tensioned and both the upper and lower blades are made of harder spring steel than in Fig. 5.2 exist. Fig. 6: Side view of a drive unit according to the invention Fig. 7: Alternative arrangement of a cutting device with two cutting blades

[0042] Fig. Figure 1 shows a drive unit with a cutting device 1 having a lateral drive shaft 2 parallel to the cutting axis 3. In the assembled state, the cutting device 1 is driven by a drive in the form of an electric motor. The electric motor is preferably part of a hand-held cleaning and maintenance device 4, as shown in Figure 1. Fig. Figure 2 shows the drive unit with cutting device. It comprises a gearbox unit 5 with a gearbox housing and height-adjustable wheel 6, and on the opposite side, a support arm 7 with a similarly height-adjustable wheel 8. The gearbox unit 5 is driven by the electric motor of the hand-held cleaning and maintenance device. The gearbox unit 5 is designed as a bevel gear drive, so that the horizontally introduced rotational energy is converted vertically. The cutter bar 9 is held by the support arm 7 and the gearbox housing 5. The cutter ends are limited by guide elements 10 with a sliding shoe 11 and a grass guide 12. Grass near the edge, in particular grass leaves and / or blades of grass, is guided into the cutter bar by the grass guide 12 of the guide element 10 and cut. This preferably ensures that even grass, grass leaves, or blades of grass growing close to the wall or fence are cut.The rotational speed of the drive of the cleaning and maintenance device is adjustable in six steps from 600 to 1,600 revolutions per minute. The drive shaft 2 of the gear unit 5 is preferably driven by the motor of the hand-held cleaning and maintenance device. The height adjustment of the wheels 8, 6 is effected by means of levers 34, 35. Preferably, the drive unit with gearbox, in particular bevel gear drive, can be driven directly by the electric motor of the hand-held cleaning and maintenance device. In such a case, a simple, preferably tool-free, exchange of, for example, a roller, which is shown in the cleaning and maintenance device of DE 10 2014 010 692 A1, for the drive unit with cutting device according to the invention is possible. A cleaning and maintenance device with a cutting device 1, which is connected to the electric motor of the cleaning and maintenance device, preferably according to DE 10 2014 010 692 A1, is shown. Fig. 2. Reference numeral 4 designates the handle for guiding the hand-held cleaning and maintenance device. The cleaning and maintenance device is preferably a cleaning and maintenance device as shown in DE 10 2014 010 692 A1.

[0043] Fig. Figure 3 shows the gear unit 5 with an input shaft that is identical to the drive shaft 2. To convert the horizontally introduced rotational energy into a vertical one, a bevel gear stage 14, preferably with a 1:1 ratio, is used. The vertical shaft 15 connected to the bevel gear stage 14 has two eccentrically arranged circular disks 16 and 17, offset by 180°, in its lower region for driving the blades of the cutting device, preferably via lugs. Fig. Figure 3 also shows the upper blade 18 and the lower blade 19. The gearbox housing 5 comprises an inner gearbox housing 42 and an outer gearbox housing 43.

[0044] The conversion of the rotational energy of the electric motor into translational kinetic energy of the respective upper 18 and lower blades 19 is shown in a first embodiment of a cutting device with upper blade 18 and lower blade 19. Fig. 4.1. The translational movement of the upper knife 18 and lower knife 19 is preferably an oscillating movement.

[0045] In Fig. Figure 4.2 shows a top view of a second embodiment of a cutting device with an upper blade 18 and a lower blade 19. In the second embodiment of the cutting device, the upper blade is under preload. The preload is generated by a spacer element or insert 37, which keeps the tabs or blade tabs 20 on the upper blade 18 at a distance from the blade tabs 21 on the lower blade 19, as in the first embodiment shown in Figure 4.2. Fig. 5.2 shown, and additionally builds up a tension in the upper blade 18. Alternatively to the design according to Fig. 5.2 The preload can also be achieved by a design according to Fig. 5.3 is applied if a harder spring steel is used than in the embodiment according to. Fig. 5.2 is used.

[0046] While in the embodiment of Fig. 4.1, how Fig. Figure 5.1 shows that the upper and lower blades rest directly on each other without any space, which leads to high friction losses. The spacer element or insert ensures that these friction losses are avoided. The height of the spacer element or insert, used to reduce friction between the upper and lower blades, is preferably in the range of 2 to 6 mm, and particularly preferably 3 mm. If a preload is to be applied to the blade, the height of the spacer element is increased by 1.5 mm, so that the entire spacer element preferably has a height of 4.5 mm. This is shown in the embodiment in Figure 5.1. Fig. 5.2 shown. Fig. Figure 5.2 shows the distance a from the center of the knife or scan profile 32 to the knife tab on the upper knife and the distance a' from the scan profile to the knife tip. In the embodiment according to... Fig. 5.2 The spacer element 37 has two heights H1 and H2, which together form a distance H. In one embodiment, the height H1 is approximately 3 mm and provides a structural distance between the tabs that drive the upper and lower blades. The additional height H1 ensures that a preload is built up so that the upper and lower blades, and in particular the cutting edges, are in contact, thus providing a clean cut, especially of grass blades.

[0047] In the alternative design according to Fig. 5.3 A height H1 is not necessary to provide a spacing between the tabs. Here, a preload is applied to the upper blade simply by inserting a single spacer 37. This also requires that the selected spring steel is harder. Fig. 5.3 The same reference numbers denote the same components as in Fig. 5.2, so upper and lower knives 18, 19 and the tabs 20, 21.

[0048] In the Fig. In the further embodiment of the invention shown in Figure 5.3, with a harder spring steel for the upper and lower blades 18, 19, only one spacer element with a single height H of 1.3 mm is shown for building up the preload. In the design of Fig. 5.3 has shown that reliable operation is possible even without the 3 mm spacing of the tabs. Without applying a preload by the spacer 37, the upper and lower blades would lie flush against each other, as in Fig. 5.1 shown. With the spacer 37 and a distance of H = 1.3 mm, sufficient pre-tension can be achieved so that the cutting edges of the knife blades touch under tension during the cutting process, thus enabling, for example, high-quality cutting of grass blades from lawns.

[0049] Fig. 5.1 is a sectional view along section AA in Fig. 4.1 of the first embodiment of the cutting device with upper and lower blade and Fig. 5.2 a side view along section AA in Fig. 4.2 of the second embodiment of the cutting device with upper and lower blades 17, 18 wherein at Fig. 5.2 how Fig. 5.3 an insert 37 in the form of a spacer or a distance element 37 is introduced between the upper and lower blades 18, 19, which causes the upper blade 18 and lower blade 19 to be positioned in the embodiment according to Fig. 5.2 can move without friction losses. Furthermore, both at Fig. 5.2 how Fig. 5.3 The upper blade 18 is under tension and rests against the lower blade under tension, so that an optimal cutting result is achieved, especially for grass blades. In Fig. 5.2 The height of the spacer element, which ensures low-friction translational movement of the upper and lower blades, is denoted by H1, and the additional height, which leads to preload, is denoted by H2. The total height of the spacer element is then H = H1 + H2. Fig. Section 5.3 specifies only one height H, which provides a preload. This height H is approximately 1.3 mm.

[0050] A further advantage of a cutting device with an upper and a lower blade 17, 18, which rotate in opposite directions, is that the vibration amplitude is halved, thus significantly reducing the vibration caused by the translational oscillating movement. Furthermore, this reduces the wear on eccentric discs 16 and 17. The blade tabs 20 and 21, which are located in the Fig. Figures 4.1 and 4.2 show that the translational oscillating movement is transmitted from the eccentric discs with their respective slotted guides 23 and 24 to the associated upper and lower blades 18, 19. The base plate 22 of the upper and lower blades 18, 19 has fixed teeth 26 in its front area, which in the illustrated embodiment are Fig. 4.2 The upper and lower knives 18 and 19 are positioned 2 mm in front of the movable knives 18 and 19 with the knife blades 30 and 31. This ensures increased cutting protection; for example, the bark is not damaged by the movable knives with knife blades 30 and 31 when they come into contact with trees. Furthermore, there is a gap between the fixed teeth 26 of the base plate 22 and the lower knife 19 to avoid unnecessary friction losses. To ensure that the upper and lower knives deliver a good cutting result, they move within the... Fig. In the embodiments shown in Figures 4.1 to 5.2, the clamping profile is positioned between the base plate 22 and the clamping profile 32. The clamping profile is held at a precise distance from the base plate by spacers 25 and tightened with screws 27. The clamping profile (32) generally has high bending and torsional stiffness. When used with trimmers on uneven turf, it ensures that the predetermined distance between the upper and lower blades remains constant thanks to the spacers 25 and the insert. The height of the spacers 25 is determined such that the cutting edges, i.e., the teeth 30, 31 of the upper and lower blades 18, 19, are in contact, but the friction between them is low. To increase the preload of the blades 30 and 31 on the cutting surface, spacers can be positioned between the clamping bars 28 and 29, which connect to the tabs 20, 21, in the rear region of the upper and lower blades.These are preferably made of steel or Teflon to minimize friction between the upper and lower blades. On the drive side, the preload can be increased by raising the spacer element or standoff 37 by 1.5 mm, as shown in [reference]. Fig. As shown in Figure 5.2, the spacer can be adjusted or enabled between the knife tabs 20 and 21. The increase in the spacer by H2 can be in a range of 1 mm to 3 mm, depending on the desired preload. Preferably, the insertion raises the tab or knife tab 20 upwards, thus creating the preload.

[0051] Alternatively to the one in the Fig. The first embodiment of a cutting device with an upper blade 18 and a lower blade 19 shown in Figures 4.1 and 5.1 shows the Fig. 4.2 and 5.2 show a second embodiment of a cutting device. As in the first embodiment, the second embodiment also shows an upper blade 18 and a lower blade 19 with pointed cutting edges. A disadvantage of the cutting edges of the upper and lower blades is that they bend easily under load, thus preventing a satisfactory cutting result. However, the elasticity of the cutting edges can also be used. Thus, according to the second embodiment, the Fig. In the embodiment shown in Figures 4.2 and 5.2, an insert 37 in the form of a spacer is inserted. Inserting the insert 37 firstly sets a distance between the upper and lower blades, thus minimizing friction, and secondly, it increases the distance by applying a preload to the upper blade 18. According to the invention, this preload, when applied to the rear of the blades as in the present case, ensures a clean cut of grass blades in a lawn. Preferably, the height H1 of the insert for reducing friction between the upper and lower blades is approximately 3 mm. The additional height H2 for building up the preload is preferably 1.5 mm, so that the total height of the insert is 4.2 to 4.5 mm. It is particularly preferred if H1 = 0 mm and H2 = 1.3 mm, i.e., the upper and lower blades are arranged as shown in Figures 4.2 and 5.2. Fig. Shown in section 5.3. Due to the preload according to... Fig. 5.2 and Fig. 5.3 The upper and lower blades 18, 19 are spaced apart, with the distance decreasing towards the blade edge. The contact point of the cutting edges of the upper and lower blades 18, 19 is then under preload. This preload ensures that the cutting edges remain in contact during operation. If the preload is insufficient or absent, material to be cut, such as blades of grass, cannot be cut. In such a case, the material, such as the blade of grass, will bend. A further advantage of the elasticity is that the elasticity of the blades reduces friction and thus the required motor power. The overall height set by the insert or spacer between the upper and lower blades is preferably 4–6 mm. The additional distance for applying the preload is preferably 1–2 mm, ideally 1.3–1.5 mm.Furthermore, the insert 37, in particular the spacer, is located a distance from the center of the upper or lower blade. The greater the distance of the insert or spacer 37 from the center of the blade, the less sensitive the spring preload is to spacing tolerances. A distance a of 20–60 mm, ideally 48 mm, is preferred to enable optimal preload force. The greater the distance of the insert 37 from the center of the clamping profile 32, the lower the preload force is for the same tab spacing. If the distance of the insert 37 from the center of the clamping profile 32 is smaller, the tab spacing could be reduced by shortening the insert 37 to achieve the same spring preload or preload. However, the preload on the cutting edges is very sensitive to manufacturing tolerances.Unfavorable manufacturing tolerances can lead to a loss of preload if the distance a is too small, thus negatively affecting the cutting quality.

[0052] In the embodiment that is in Fig. As shown in Figure 4.2, the preload is applied by the spacer or insert 37 arranged in the area of ​​the tab. A problem with this embodiment is that the preload is only applied to the portion of the upper blade 18 opposite the tab. Areas of the upper blade that are farther from the tab, for example on the opposite side, then have no or only insufficient preload, so that a consistently good cutting result is not achieved across the entire width of the blade. In a further developed embodiment according to Fig. 4.3 The knife is provided with an additional tab, or additional knife tab 120, for the upper knife and an additional knife tab 121 for the lower knife. Like the tabs 20 and 21, the additional tab 120, 121 includes an insert 37.2 in the form of a spacer. This insert 37.2 serves solely to apply the preload, as with the tabs 20 and 21, which are driven by the eccentric discs. Therefore, the height of the insert 37.2 can be selected so that only the preload is applied, for example, 1.5 mm. Of course, larger heights, for example of 4.5 mm, would also be possible, as with the spacer in the area of ​​tabs 20, 21. This measure ensures that the upper and lower blades are in contact at the cutting edges across the entire width of the blade, so that a good cutting result for grass, especially for grass blades in a lawn, is achieved across the entire width.Wide knives can be fitted with a variety of additional tabs, e.g., two, three, etc. additional tabs. In particular, two pre-tensioning devices, i.e., two tabs, as shown in [reference], can be used. Fig. As shown in Figure 4.3, an even distribution of the pretension across the blades is achieved. The variant using two pretensioning devices results in a better cutting performance, since with only one pretensioning device or tab, the grass in the opposite area, as shown in Figure 4.3, is cut more evenly. Fig. 4.2 shows that the cut is inadequate. This is also in contrast to the cut shown in Fig. The arrangement shown in 4.1 could be compared with the arrangement with two tabs in Fig. 4.3 The best cutting results are achieved for dry and wet grass.

[0053] The preload devices shown in the prior art, e.g., in DE 38 212 35 A1 or US 2,702,978 A, are used for rotary-oscillating knives, in contrast to the translational knives of the invention. Applying a preload as shown is a previously unknown method for translationally oscillating knife bars.

[0054] In the prior art, preload on cutter bars is typically achieved by a multitude of clamping jaws that compress the blades at the front. Applying preload to the cutter bars at the front of the blades, as shown in the prior art (e.g., IUS 2,702,978 A), has the disadvantage of hindering grass removal. This impairs the cutting quality, and a clean cut of grass blades is not possible in the prior art; only the cutting of grass stalks, such as those found in a meadow, is possible. In contrast, the invention, with inserts arranged at the rear of the blade for applying preload, enables the cutting of grass blades from a lawn.The reason why cutting grass blades is not possible in prior art applications such as DE 38 212 35 A1 or US 2,702,978 A is that, with pre-tensioned blades in the front section, the material being cut is guided onto the upper blade behind the cutting edges and then transported to the sides and deposited by the oscillating movement of the upper blade. Tensioning devices in the front section, as in the prior art, thus impede the lateral transport of the material being cut. In particular, a prior art embodiment according to US 2,702,978 A is shown. In US 2,702,978 A, the grass is cut, pressed in the cutting direction by the upper blade (referred to as the "upper section" in US 2,702,978 A), and then falls forward into the grass being cut. This significantly reduces the cutting quality.If the preload according to the invention is not applied in the front area of ​​the cutting blades, but in the rear area of ​​the upper and lower blades by means of spacer elements or inserts as in . Fig. 5.2 and Fig. 5.3 If the tensioning device is applied, the cut material will not fall forward but will be directed to the sides, and in particular, continuously directed, without impairing the cutting process and / or the cutting quality, thus enabling the cutting of grass blades. Particularly good cutting results are achieved when the tensioning device, especially the inserts that provide the additional clearance, is positioned 60 mm to 100 mm from the tip of the cutting blade.

[0055] The thickness of the blades is preferably between 1 and 1.5 mm. It is preferred that the blades can bend elastically, particularly to build up preload. Thinner blades with a material thickness of less than 1 mm are subject to higher wear and cannot achieve the desired preload. Material thicknesses above 1.5 mm are not elastic enough, and the friction at the cutting edges would be too high. This would increase motor power consumption and blade wear. Surprisingly, a blade thickness between 1 mm and 1.5 mm avoids both of the aforementioned disadvantages.

[0056] To ensure reliable force transmission to the upper and lower blades, it has been found that the blade tabs 20, 21 of the upper and lower blades should have a distance of 2–6 mm, particularly 3 mm, in the area of ​​the eccentric to achieve reliable force transmission from the eccentric discs to the tabs. If both tabs lie directly against each other, the friction is too high, and there is a risk that the eccentric discs will jump out of the elongated guide slots 23 and 24 of the blade tabs. Jumping out of the blade tabs 20 and 21 in the area of ​​the elongated guide slots is prevented by using an intermediate disc 38 made of hardened steel. The outer diameter of the intermediate disc is large enough to largely cover both elongated holes of the blade tabs. In addition to maintaining the distance between the blade tabs as described above, the disc also prevents the blade tabs from jumping out onto the other eccentric.This is particularly true for the embodiment according to . Fig. 5.2 case.

[0057] In the event of a sudden blockage of the cutting blades 18 and 19 by the material being cut while the motor is running, the gearbox housing 5 has a two-part design. The two-part housing absorbs the resulting forces. The two-part gearbox housing consists of an inner housing 42 and an outer housing 43. The inner housing 42 absorbs the lateral forces generated during blade blockage by the eccentric discs 16 and 17 on the one hand and by the bevel gears 14 on the other. The two-part housing is in Fig. 3 shown.

[0058] Fig. Figure 6 is a side view of the drive unit according to the invention. Fig. Figure 6 shows the height adjustments 34 and 35 of the wheels, which allow for three cutting heights of 3, 4, and 5 mm. This range is generally recommended for lawns. To prevent the blades 18 and 19 from sinking too deeply into the ground due to tipping of the cleaning and maintenance device, gliding shoes 11 are attached to the guide rails 10 to the right and left of the blades. The cover 36 of the Fig. The device shown in Figure 1 serves to transport the material being cut to the rear area in order to ensure a view of the knife blades.

[0059] Fig.Figure 7 shows an alternative embodiment of the invention, wherein the drive arrangement of the cutting device is located in the center of the cutting device. The motor is then arranged vertically and is connected to the cutting device directly in a housing via a gear stage for speed reduction and an eccentric drive. This arrangement is particularly suitable for a device in which the motor shaft drives the blades vertically and directly via a gear stage and eccentric discs. Identical components as in the preceding figures are designated with the same reference numerals.

[0060] The invention provides an easily interchangeable drive unit with a cutting device for use in a hand-operated cleaning and maintenance device. The drive is powered by the same motor as, for example, the drive of a roller in the cleaning and maintenance device. The roller and cutting device of the cleaning and maintenance device can be easily exchanged for the drive unit with cutting device without tools. With the described cleaning and maintenance device, different functions for cleaning and maintenance in the house and garden can be provided by changing the working device. This is particularly possible because all working devices can be quickly exchanged without tools.

[0061] While the prior art according to US 2,702,978 A is also driven by an electric motor, and various attachments can be mounted to the bottom of the handle using a locking nut, the drive shaft is located within the handle. A disadvantage of this is that the drive train is very long, and all components must be designed to withstand the high stress that occurs when the blades lock during operation. As a result, the device according to US 2,702,978 A is heavy and requires considerable effort to move. US 2,702,978 A uses rollers instead of wheels to prevent, for example, wheels from penetrating the ground; however, these rollers have significantly higher rolling resistance than wheels, requiring the operator to exert considerable force. In contrast, the invention allows the use of wheels due to its lightweight design.In contrast, the mechanical stress on the drive shafts and transmission components of the drive train is low in the invention. The motor is positioned transversely above the blade, and the blade is supported by the two outer housing parts. Because the blade bar is structurally supported at its outer ends in the invention, the overall structure is mechanically rigid, and the components can be designed to be lighter. No vertical bending forces occur at the outer ends of the blade bars, as is the case in the prior art of US 2,702,978 A, KR 20 2000 0004 787 U, or DE 38 212 385 A1. Unlike devices according to the prior art, the cutting device according to the invention enables the clean cutting of grass blades in a lawn. This is primarily due to the fact that the mechanism for applying the preload force is located in the rear area of ​​the cutting blades.

[0062] Reference number list 1. Cutting device 2. Side drive shaft on the cutting device 3. Cutting axis 4. Cleaning and maintenance equipment 5. Gear unit 6. Right wheel 7. Support arm 8. Left wheel 9. Knife bar 10. Guidance device 11. Gliding shoe 12. Grass blade guidance 14th bevel gear stage 15. Vertical wave 16. Circular, eccentrically arranged, upper disc 17. Circular, eccentrically arranged, lower disc 18. Upper knife 19. Lower knife 20. Knife tab on the upper knife 21. Knife tab on the lower knife 22. Base plate 23. Slotted guide upper knife tab 24. Slotted guide lower knife tab 25. Spacers 26. Fixed teeth of the base plate 27. Connecting screws 28. Upper pre-tensioning tab 29. Lower tensioning tab 30th tooth of the upper blade 31st tooth of the lower knife 32. Tension profile 37, 37.1, 37.2 Insert or spacer 38. Intermediate disc 42. Inner gearbox housing 43. Outer gearbox housing 90. Knife tip 120th additional tab 121st additional tab

[0063] The invention includes aspects set out in the following sentences, which are part of the description but are not claims according to J15 / 88. Sentences

[0064] 1. Working unit, preferably mountable on a hand-operated cleaning and maintenance device, designed with a cutting device (1) a drive shaft (2) arranged laterally behind the cutting device (1) parallel to a cutting axis of the cutting device (1) characterized in that the drive shaft (2) via a gearbox, preferably a bevel gear gearbox (14), in particular a 90° bevel gear gearbox, with the cutting device is connected in such a way that preferably a rotary movement of the drive shaft (2) is converted into an oscillating, in particular translational, movement of the cutting device (1).

[0065] 2. Drive unit according to sentence 1, characterized by the fact that the drive shaft (2) is connected to a drive device, preferably an electric motor, in particular a hand-held cleaning and maintenance device.

[0066] 3. Work unit according to sentence 1 or 2, characterized by the fact that the cutting device (1) has a cutting width in the range of 100 mm to 500 mm.

[0067] 4. Drive unit according to one of sentences 1 to 3 characterized by the fact that the cutting device (1) preferably comprises two counter-rotating cutting blades (18,19), in particular an upper blade (18) and a lower blade (19).

[0068] 5. Drive unit according to sentence 4, characterized by the fact that An insert (37, 37.1, 37.2), in particular a spacer, is provided between the upper blade (18) and the lower blade (19) such that a preload is applied to the upper blade (18) by adjusting the distance between the upper and lower blades.

[0069] 6. Drive unit according to sentence 5, characterized by the fact that the distance between the upper and lower blades set by the insert (37, 37.1, 37.2), in particular spacers, is in the range of 1 to 6 mm and includes an additional distance of 1 to 2 mm, preferably 1.5 mm, for building up the preload.

[0070] 7. Drive unit according to one of sentences 4 to 6, characterized by the fact that the upper knife (18) and the lower knife (19) shall include at least one tab (20, 21).

[0071] 8. Drive unit according to sentences 4 to 6, characterized by the fact that the upper knife (18) and the lower knife (19) shall also include at least one additional tab (120, 121).

[0072] 9. Drive unit according to one of sentences 1 to 8, characterized by the fact that the insert, in particular the spacer, is arranged in the area of ​​the tab (20, 21) and / or the additional tab (120, 121).

[0073] 10. Work unit according to one of sentences 1 to 9, characterized by the fact that the cutting device (1) comprises a gear unit (5), preferably with height-adjustable running wheel (6) and opposite the gear unit a support arm, preferably with height-adjustable running wheel (8).

[0074] 11. Work unit according to at least one of sentences 1 to 10, characterized by the fact that the cutting device (1) comprises a guide device (10), preferably with sliding shoes and grass blade guide.

[0075] 12. Work unit according to at least one of sentences 1 to 11, characterized by the fact that the vertical drive shaft comprises at least one, preferably two, eccentrically arranged, in particular offset by 180°, circular disks (16, 17).

[0076] 13. Drive unit according to at least one of sentences 1 to 12, characterized by the fact that the vertical drive shaft engages with at least one, preferably two eccentrically arranged, in particular offset by 180°, circular disks (16, 17) in an opening, in particular an elongated hole of the tab (20, 21).

[0077] 14. Drive unit according to at least one of sentences 1 to 13, characterized by the fact that the insert, in particular the spacer, is arranged on the tab (20, 21) and / or the additional tab (120, 121).

[0078] 15. Work unit according to at least one of sentences 1 to 14, characterized by the fact that the cutting device (1) comprises a base plate (22) and a clamping profile (32), wherein the cutting blade(s) are arranged between the base plate (22) and the clamping profile (32).

[0079] 16. Working unit according to one of claims 1 to 15, characterized in that The base plate (22) and the clamping profile (32) are spaced apart by spacer sleeves.

[0080] 17. Work unit according to one of sentences 1 to 16, characterized by the fact that the height of the spacer sleeves (25), preferably made of Teflon and / or steel, is selected such that the cutting edges of the cutting blades (18,19) are in contact with only slight friction.

[0081] 18. Work unit according to one of sentences 1 to 17, characterized by the fact that the gear unit (5) comprises an inner (32) and an outer housing (33).

[0082] 19. Work unit according to one of sentences 1 to 18, characterized by the fact that the cutting device (1) includes a cover. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 3,623,223 A

[0004] EP 2853142 A1

[0005] WO 1999 / 07202 A1

[0005] EP 1886551 A1

[0006] US 2,702,978 [0007, 0008, 0024, 0033, 0053, 0054, 0061] DE 38 212 35 A1 [0008, 0018, 0019, 0033, 0053, 0054] DE 10 2005 049 665 A1

[0009] KR 20 2000 0004 4787 U

[0010] OF 10 2014 010 692 A1 [0024, 0042] DE 10 2014 010 692 A2

[0025] KR 20 2000 0004 787 U

[0061] DE 38 212 385 A1

[0061]

Claims

[1] Working unit, preferably mountable on a hand-operated cleaning and maintenance device, designed with a cutting device (1), in particular for cutting grass blades of a lawn, a drive shaft (2) arranged laterally behind the cutting device (1) parallel to a cutting axis of the cutting device (1) characterized by , that the drive shaft (2) is connected to the cutting device via a gearbox, preferably a bevel gear gearbox (14), in particular a 90° bevel gear gearbox, such that a rotary movement of the drive shaft (2) is converted into an oscillating, in particular translational movement of the upper blade (18) and lower blade (19). [2] Drive unit according to claim 1, characterized by, that the drive unit comprises at least one motor, in particular an electric motor, which is preferably arranged centrally and parallel to the cutting axis (3) and which is connected to the drive shaft in such a way that the drive shaft can be rotated parallel to the cutting axis. [3] Drive unit according to claim 1 or 2, characterized by , that the drive shaft (2) is connected to the drive device, in particular of a hand-held cleaning and maintenance device. [4] Working unit according to one of claims 1 to 3, characterized by , that the cutting device (1) has a cutting width in the range of 100 mm to 500 mm and / or the cutting device (1) preferably comprises two counter-rotating cutting blades (18,19), in particular an upper blade (18) and a lower blade (19). [5] Drive unit according to claim 4, characterized by , that an insert (37, 37.1, 37.2), in particular a spacer, is provided between the upper blade (18) and the lower blade (19) such that a preload is applied to the upper blade (18) by adjusting the distance between the upper and lower blades, in particular the distance between the upper and lower blades set by the insert (37, 37.1, 37.2), in particular spacers, is in the range of 0 to 6 mm and includes an additional distance of 1 to 2 mm, preferably 1.5 mm, for building up the preload and / or the inserts are in the range of 60 to 100 mm away from the blade tips (90). [6] Drive unit according to any one of claims 4 to 6, characterized by , that the upper blade (18) and the lower blade (19) comprise at least one tab (20, 21) and / or the upper knife (18) and the lower knife (19) shall further comprise at least one additional tab (120, 121). [7] Drive unit according to claim 6, characterized by , that the insert, in particular the spacer, is arranged in the area of ​​the tab (20, 21) and / or the additional tab (120, 121). [8] Working unit according to at least one of claims 1 to 7, characterized by , that the cutting device (1) comprises a guide device (10), preferably with sliding shoes and grass blade guide. [9] Working unit according to at least one of claims 1 to 8, characterized by , that the drive shaft (2) comprises at least one, preferably two eccentrically arranged, in particular offset by 180°, circular disks (16, 17). [10] Drive unit according to at least one of claims 1 to 9, characterized by , that the vertical drive shaft engages with at least one, preferably two eccentrically arranged, in particular offset by 180°, circular disks (16, 17) in an opening, in particular an elongated hole of the tab (20, 21) and / or the insert, in particular the spacer, is arranged on the tab (20, 21) and / or the additional tab (120, 121). [11] Working unit according to at least one of claims 1 to 10, characterized by , that the cutting device (1) comprises a base plate (22) and a clamping profile (32), wherein the cutting blade(s) are arranged between the base plate (22) and the clamping profile (32), and in particular the base plate (22) and the clamping profile (32) are spaced apart by spacer sleeves. [12] Working unit according to any one of claims 1 to 11, characterized by , that the height of the spacer sleeves (25), preferably made of Teflon and / or steel, is selected such that the cutting edges of the cutting blades (18,19) are in contact with only slight friction. [13] Working unit according to any one of claims 1 to 12, characterized by , that the gear unit (5) comprises an inner (42) and an outer housing (43). [14] Working unit according to any one of claims 1 to 13, characterized by , that the cutting device (1) includes a cover. [15] Handheld cleaning and maintenance device with a drive unit, in particular a motor, preferably an electric motor, characterized by , that the hand-held cleaning and maintenance device comprises a working unit according to one of claims 1 to 14, which is preferably connected to the drive shaft of the working unit.

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