EP3128827A1

EP3128827A1 - Improved robotic working tool

Info

Publication number: EP3128827A1
Application number: EP14718036.8A
Authority: EP
Inventors: Jonathan BJÖRN; Gustav Landberg; Martin Elonsson
Original assignee: Husqvarna AB
Current assignee: Husqvarna AB
Priority date: 2014-04-11
Filing date: 2014-04-11
Publication date: 2017-02-15
Also published as: WO2015154822A1

Abstract

A robotic work tool system (200) comprising a robotic work tool (100), said robotic work tool (100) comprising a housing (140) comprising a chassis (140B) adapted to carry at least one component (110, 120, 180, 170, 165, 160, 150), and a body (140A), wherein said body (140A) is adapted to be fitted with an exchangeable cover (310), which exchangeable cover (310) is arranged to be attached to said body (140A) through releasable attachment means (410, 415, 420,425, 430, 435).

Description

IMPROVED ROBOTIC WORKING TOOL

TECHNICAL FIELD

This application relates to a robotic work tool system for improved update of a robotic work tool body and a cover to be used with a robotic work tool.

BACKGROUND

Many robotic work tools operate in outdoor environments where they are affected by wear and tear factors such as weather, but also collisions and scratching upon contact with other objects.

For example, a robotic work tool operating in a garden may have its upper part scratched as it drives in under low hanging trees or bushes. They may also be scratched by garden furniture or other structures commonly found in a garden.

As a body for a robotic work tool becomes scratched or otherwise damaged they should be replaced, both to provide a more aesthetic appearance, but also to protect the components being covered by the body. For example, should a body be cracked the collision and/or lift detection may be affected and in worst cases, water may leak through the crack and cause damage to various components for example through erosion.

To change a body or hull of a robotic work tool generally requires a lot of work, is complicated, requires tools and also requires precision.

Usually the body is connected to the components through various cables that need to be routed correctly when replacing a body. Also, should a body be fitted incorrectly a lift and/or collision detection system of the robotic work tool may not be able to operate correctly which will significantly impair the operation of the robotic work tool and may also increase the risk for causing damage by the robotic work tool.

Also, and of great importance, is that once the body is removed the cabling and possibly also some of the components are exposed which may lead to the user damaging the components or cabling or - in worst cases - the user being hurt by the components if they are handled incorrectly. For example, while the robotic work tool is being charged it is subjected to charging currents of up to 2-4 Amperes. Should a user attempt to change the cover during a charging session he may thus be subjected to such charging currents if handling the robotic work tool incorrectly.

In general, a technically unskilled user should be refrained from making adaptations or modifications to the general body of a robotic work tool as many functions depend on a correct assembly.

Commonly, a professional service technician is therefore hired to exchange a robotic work tool's body should it need to be replaced.

There is thus a need for a robotic work tool system where a body can be easily updated without requiring any special skills or tools and without risking impairing the functionality of the robotic work tool.

SUMMARY

It is an object of the teachings of this application to overcome the problems listed above by providing robotic work tool system comprising a robotic work tool comprising a housing comprising a chassis adapted to carry at least one component, and a body, wherein said body is arranged to cover said at least one component and wherein said body is adapted to be fitted with an exchangeable cover, which exchangeable cover is arranged to be attached to said body through releasable attachment means.

By realizing that by fitting a removable and user exchangeable cover over at least a part of the body, a fast and efficient manner that is safe is provided for a user to replace a damaged cover. As the cover would be on an outer side of the body, it would be the cover that primarily would be scratched when in contact with any external objects and thus, only the cover needs to be replaced.

In one embodiment the body is arranged to operate as part of a lift or collision detection.

In one embodiment the body is arranged to cover said at least one component. It is also an object of the teachings of this application to overcome the problems listed above by providing a cover adapted to be releasably attached to a body of a robotic work tool by use of releasable attachment means.

In one embodiment, the releasable attachment means comprises at least one hook and slot attachment means for simple attachment and removal of said cover by guiding a hook into a slot. It should be noted that, as an alternative to a hook-slot attachment means, a hook- loop attachment means may be used.

It is also an object of the teachings of this application to overcome the problems listed above by providing a robotic work tool comprising a body which is adapted to receive a cover according to above, said body comprising corresponding releasable attachment means.

In one embodiment, the body is adapted to receive a cover according to above, said body comprising corresponding hook and slot releasable attachment means.

The inventors of the present invention have realized, after inventive and insightful reasoning, that a robotic work tool's body may be supplied with a user- exchangeable cover which would be easy to replace. As the body covers all the components no risk of causing damage to or from the components would be present as the body would not be removed, only the cover. Also, such a cover would not require to be fastened as securely as the robotic work tool would be operate satisfactorily even if the cover became loose or was ill-fitted.

It should be noted that the integrity of the body, including its arrangement, is of high importance for robotic work tools as they are detrimental to a proper collision detection and also a proper lift detection. Both functions have both operational aspects as well as safety aspects. Furthermore, the body provides a safety distance to a work tool, such as a cutting disc in the case of the robotic work tool being a robotic lawn mower. Furthermore, some of the cabling of the robotic work tool may be damaged should the body be removed or improperly arranged.

A proper fitting of the body is therefore of the highest importance and should not be performed or modified by a technically unskilled person.

With the robotic work tool according to the teachings herein, the electronics provided in the robotic work tool are always protected against access by the user when the housing is modified or updated. Therefore, if one cover is to be replaced by another in order to replace a broken or scratched cover (or to give the robotic work tool a new design), there is no risk of the electronics present in the housing being damaged when the covers are interchanged or of the user being subjected to danger by the electronics present inside the housing. In this respect, the cover could even be interchanged when the robotic work tool is charging and/or even during bad weather.

Furthermore, by making use of the flexibility of the cover structure resulting from the use of a (relatively) thin cover and the flat form of the cover in combination with the wide overall extension of the cover, the cover may easily be attached using hooks in both the front and the rear of the robotic work tool. The cover may then be secured with only a few releasable clips in the centre of the robotic work tool which allows for a simple and quick attachment as well as removal of the cover. Alternatively, the hooks and corresponding slots may be arranged on either side of the robotic work tool.

As the cover is easily replaced even by a user, it can be changed at will and also for only aesthetic purposes. A user or retailer may thus customize a robotic work tool by changing the colour or pattern of the cover, thereby changing the overall appearance of the robotic work tool.

With the robotic work tool according to the teachings herein, a user thus has the possibility of modifying the appearance or design of the housing in an extremely short time and without any difficulty by selecting and fitting on an appropriate cover. The user can thus more or less change the cover according to his/her wishes if external elements with different shapes and colours are available to him/her for this purpose.

In one embodiment the robotic work tool is a robotic lawnmower. In one embodiment the robotic work tool 100 is a farming equipment. In one embodiment the robotic work tool 100 is a golf ball collecting tool. The robotic work tool 100 may also be a vacuum cleaner, a floor cleaner, a street sweeper, a snow removal tool, a mine clearance robot or any other robotic work tool that is required to operate in a work area in a methodical and systematic or position oriented manner. Other features and advantages of the disclosed embodiments will appear from the following detailed disclosure, from the attached dependent claims as well as from the drawings.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [element, device, component, means, step, etc]" are to be interpreted openly as referring to at least one instance of the element, device, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

BRIEF DESCRIPTION OF DRAWINGS

The invention will be described in further detail under reference to the accompanying drawings in which:

Figure 1 A shows a schematic overview of a robotic work tool according to one embodiment of the teachings of this application in a top view;

Figure IB shows a schematic overview of a robotic work tool according to one embodiment of the teachings of this application in a side view;

Figure 2 shows a schematic view of a robotic working tool system according to one embodiment of the teachings of this application;

Figure 3 shows a side view of a body 140 A to be mounted on a robotic work tool according to one embodiment of the teachings of this application;

Figure 4A shows an upper view of a cover according to one embodiment of the teachings of this application;

Figure 4B shows a side view of a body according to one embodiment of the teachings of this application;

Figure 4C shows a corresponding under side view of a cover according to one embodiment of the teachings of this application;

Figure 5 shows a close-up view of hook-slot attachment means according to one embodiment of the teachings of this application; Figure 6 shows a close-up view of releasable attachment means according to one embodiment of the teachings of this application; and

Figure 7 shows an example of a friction-based attachment means according to one embodiment of the teachings of this application.

DETAILED DESCRIPTION

The disclosed embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein;

rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

Figure 1 A shows a schematic overview of a robotic work tool 100 having a housing 140 and a plurality of wheels 130. In the exemplary embodiment of figure 1 the robotic work tool 100 has 4 wheels 130, two front wheels 130' and the rear wheels 130". At least some of the wheels 130 are drivably connected to at least one electric motor 150. It should be noted that even if the description herein is focussed on electric motors, combustion engines may alternatively be used possibly in combination with an electric motor.

In the example of figure 1, the rear wheels 130" are connected to each an electric motor 150. This allows for driving the rear wheels 130" independently of one another which, for example, enables steep turning.

The robotic work tool 100 also comprises a controller 110 which is configured to read instructions from a memory 120 and execute these instructions to control the operation of the robotic work tool 100.

The robotic work tool 100 further has at least one sensor 170 arranged to detect a magnetic field (not shown). The sensors are connected to the controller 110 and the controller 110 is configured to process any signals received from the sensors 170. The sensor signals may be caused by the magnetic field caused by a control signal being transmitted through a boundary wire (for more details on charging stations, control signals and boundary wires, see the description below with reference to figure 2). This enables the controller 110 to determine whether the robotic work tool 100 is inside or outside an area enclosed by a boundary wire.

The controller 110 is connected to the motors 150 for controlling the propulsion of the robotic work tool 100 which enables the robotic work tool 100 to service an enclosed area without leaving the area.

The robotic work tool 100 also comprises a work tool 160, which may be a grass cutting device, such as a rotating blade 160 driven by a cutter motor 165. The robotic work tool 100 is, in one embodiment, a robotic lawnmower.

The robotic work tool 100 may also have (at least) one battery 180 for providing power to the motors 150 and the cutter motor 165. Connected to the battery 180 are two charging connectors for receiving a charging current from a charger (referenced 220 in figure 2) of the charging station (referenced 210 in figure 2). Alternatively, the batteries may be solar charged.

Figure IB shows a schematic overview of the robotic work tool 100 wherein the housing comprises a body 140A and a chassis 140B. The chassis is adapted to carry most or all of the components of the robotic work tool 100, such as a controller/memory board 110/120 and the battery 180 to give a few examples. Other components are the sensor(s) 170 (not shown in figure IB), the motor(s) 150 (not shown in figure IB), the cutting tool 160 (not shown in figure IB) and the cutting motor (not shown in figure IB). The body 140A is arranged to cover the components to protect them from external influences.

The body 140 A may be arranged with magnetic or spring based sensors 190 for example, adapted to detect if the body 140A is moved in relation to the chassis 140B.

Corresponding sensor or sensor elements 195 are arranged on the chassis 140B. For the example of using magnetic sensors, a magnetic element 190 may be arranged on the body 140A and a corresponding magnetic sensor 195 (such as a Hall sensor) may be arranged on the chassis 140B. Should the magnetic element 190 move away from the magnetic sensor 195 (or a spring-based sensor be extended or compressed) a collision or lift has been detected. A movement upwards of the body 140 A is indicative of a lift, and a movement in a substantially horizontal direction is indicative of a collision. The body 140A is thus arranged to operate as a part of a collision and/or a detection function.

The body 140 may comprise holes or openings adapted and placed to receive a connector, a key or key panel, and/or a display or display panel. In one embodiment the body 140A is all-encompassing when arranged on the chassis 140B, possibly in combination with any connector, key or keypad, and/or display or display panel arranged on the chassis 140B. In one embodiment the body 140 A is all-encompassing when arranged at least from any user accessible surface when the robotic work tool is placed on the ground or arranged as during normal operation.

Figure 2 shows a schematic view of a robotic working tool system 200 comprising a charging station 210 and a boundary wire 250 arranged to enclose a working area 205, the working area 205 not necessarily being a part of the robot system 200.

The robotic work tool 100 of figure 2 is a robotic work tool 100 such as disclosed with reference to figure 1. A charging station 210 has a charger 220 coupled to, in this embodiment, two charging connectors 230. The charging connectors 230 are arranged to co-operate with corresponding charging connectors 185 of the robotic work tool 100 for charging the battery 180 of the robotic work tool 100.

The charging station 210 also has, or may be coupled to, a signal generator 240 for providing a control signal 255 to be transmitted through the boundary wire 250. As is known in the art, the current pulses 255 will generate a magnetic field around the boundary wire 250 which the sensors 170 of the robotic work tool 100 will detect. As the robotic work tool 100 (or more accurately, the sensor 170) crosses the boundary wire 250 the direction of the magnetic field will change. The robotic work tool 100 will thus be able to determine that the boundary wire has been crossed.

Figure 3 shows a side view of a body 140 A to be mounted on a robotic work tool such as the robotic work tool 100 of figures 1A, IB and 2. In this example embodiment, the body 140A comprises two openings 360 for receiving a key panel and a display panel.

Attached to the body is a cover 310. The cover 310 is exchangeable and can thus easily be replaced in case it gets scratched or otherwise damaged. By arranging the robotic work tool with an exchangeable or removable cover 310 several benefits are achieved.

One benefit lies in that the robotic work tool can easily be updated by removing and replacing the exchangeable cover without having to remove or open the body, which covers the components of the robotic work tool. An update can thus be performed without risking to damage the components or any risk of being damaged by a component. This is a major benefit as it concerns safety of operation, personal safety and also safety for a person's possessions.

Another benefit lies in that the cover can be used to hide design and manufacturing details for the body, which greatly simplifies the design and manufacture of the body 140A. Examples of such details are injection points, gating points, which can now be placed under the cover, and support structures which can also be arranged under the cover. Such support structures can thereby also be reinforced without affecting the overall appearance of the robotic work tool. By arranging the gating or injection points under the cover, the design of the body 140 A is greatly simplified as the gating points can now be placed at many more positions and can also be placed in positions that would otherwise be visible and affect the overall appearance or finish of the robotic work tool. The gating points can thus be placed at position increasing the flow of plastic (or other material) when moulding the body 140 A

Releases, such as screws or other means for removing the body 140A from the chassis 140B may also be arranged under the cover and thus hidden from every day access. An example of such a detail is shown with reference to figure 4B and is referenced 450. In the example of figure 4B the detail is a support structure.

Also, certain tools and accessories, such as wheel brushes, may be arranged under the cover so that they are easily accessible, as the cover itself is easily removable, without being visible and thereby affecting the overall appearance of the robotic work tool. Accessories, such as a screw driver or other tool for affixing the releases for the body may also be stored under the cover 310 so that they are easy to reach when servicing the robotic work tool. Another benefit lies in that the removal and replacement of the cover 310 will not affect the operation of the robotic work tool. Should the cover 310 be incorrectly fitted or attached to the body 140A, it will not affect the operation as it is not (directly) coupled to any operative components. For example, any lift or collision detection would not be affected by an ill fitted or removed/missing top cover 310.

Another benefit lies in that the cover 310 may be arranged to hide access points for removable or replaceable parts. Previously, a user would often have to turn the robotic work tool upside down to replace such parts.

In one embodiment, as shown in figures 3, 4A and 4C, the cover 310 has a substantially flat planar overall extension. This makes it easier to provide a lacquer to the cover 310 and several colours would be available for customizing the robotic work tool through the cover 310. Also, such a cover 310 may also be provided with a film more easily than a substantially shell shaped body 140 A, making it possible to provide patterns, for example a camouflage pattern, for customizing the robotic work tool in a simplified and cheaper manner.

In one embodiment the cover 310 is made of styrene plastics. In one such embodiment the cover 310 is made of an Acrylonitrile Styrene Acrylate (ASA) plastic. In another such embodiment the cover 310 is made of an Acrylonitrile butadiene styrene (ABS) plastic. In one embodiment the cover is made of Polypropylene. The cover may have a thickness of 1 to 5 mm, preferably about 2 mm, which due to the shape of the cover, having a substantially flat planar overall extension, makes the cover 310 flexible.

To enable a quick removal and also replacement of the cover 310, the inventors have realized that by taking advantage of the relative flexibility of the cover 310 and by arranging hook and slot attachment means at substantially opposite ends of the cover 310, the cover 310 may be easily attached and/or removed. To attach the cover 310 a user simply slides in the slots into corresponding hooks (or vice versa) at one end of the cover 310, flexes the cover 310 and slides in the slots into corresponding hooks (or vice versa) at the substantially opposite end of the cover 310. The hook and slots arranged at substantially opposite ends may be referred to as opposing hooks and slot attachment means. As the user presses don on the middle of the cover 310 - or simply lets the cover 310 straighten out by its own accord, the hook and slot attachment means slide into place. It should be noted that, as an alternative to a hook-slot attachment means, a hook-loop attachment means may be used.

To further secure the cover 310 in place one or more releasable attachments means, such as clips or push to enclose fastening means may be arranged at a mid section of the cover 310.

Also, to further maintain the cover 310 in a stable position when attached - i.e. to prevent it from moving sideways, friction-based attachment means may also be arranged. Such attachment means have the benefit in that they provide securing or anchoring points for the cover 310 while still being simple and easy to release.

As has been discussed in the above, any desired attachment means can be used to attach the cover to the housing of the robotic work tool, but attachment means based on hook-slot arrangements may preferably be used. Attachment means with a press-on/catch closure may be combined with the hook-slot attachment means for locking the cover in place. Such attachment means ensure a secure connection between the cover and the housing and, moreover, they can be easily used without a special tool being required for them.

Further details on the attachment means that may be used to attach or fit the cover 310 to the body 140A will now be disclosed with simultaneous reference to figures 4 A, 4B and 4C. Figure 4 A shows an upper view of a cover 310 and figure 4C shows a corresponding under side view of the cover 310. Figure 4B shows a side view of the body 140 A.

The cover 310 has been removed from the body 140 A in figures 4 A and figure 4B. As can be seen in figure 4B, the body 140 A is arranged with corresponding fastening means at various points. In this example there are four slots 415A and 415B arranged at a front end of the body 140A (front being in the usual direction of propulsion under normal operation of the robotic work tool) and two slots 415C arranged at an opposing rear end of the body 140A.

The cover (see figure 4C) is arranged with corresponding hooks 410, four 410A and 410B at a front end and two more hooks at a rear end 410C. Naturally, the hooks 410 and slots 415 may also be arranged at either side of the cover 310/body 140A, however, as the cover 310 usually has an extension being longer in the front-end direction, it is more flexible with regards to this direction and thus easier to remove/replace. Figure 5 shows a close-up view of such hook-slot attachment means. Portions of the body 140A are indicated with dashed lines and portions of the cover 310 are indicated with full lines. A hook is arranged on the cover 310 and a corresponding slot 415 is arranged on the body 140 A for engaging the hook 410 when attaching the cover 310 to the body 140 A.

It should be noted that even though the examples herein are focussed on having the hooks 410 arranged on the cover 310 and the slots arranged on the body 140 A it is possible to arrange the slots 415 on the cover 310 and the hooks 415 on the body 140A.

However, having the hooks arranged on the cover 310 simplifies the fitting of the cover 310 as it becomes easier to fit the cover by guiding a hook 410 into a slot 415, than vice versa.

In general for this application, herein the attachment means arranged on the cover 310 have corresponding attachment means arranged on the body 140A.

To secure the cover 310 to the body, clip-based or push to enclose releasable attachment means 420 are provided at a midsection of the cover, with corresponding protrusions or rims 425 on the body 140A. Figure 6 shows a close-up view of such releasable attachment means 420. Portions of the body 140A are indicated with dashed lines and portions of the cover 310 are indicated with full lines. In this example, the releasable attachment means is a clip-based attachment means 420 arranged on the cover 310 and a protruding edge 425 arranged on the body 140 A.

The clip 420 is arranged to be inserted through a hole or opening 426 in the body 140 A. To facilitate the attachment of the cover 310 to the body 140 A, the attachment means 420 may be arranged with guides 427 for correctly guiding the clip 420 through the opening 426 in the body 140 A.

To provide increased stability and also a more secure attachment one or more friction-based attachment means 430 may be arranged on the cover 310 for cooperating with a corresponding surface 435 arranged on the body 140. Figure 7 shows an example of such a friction-based attachment means 430 wherein a tongue 430 protrudes from the cover 310 for engaging a lip 435. The tongue 430 is arranged to be inserted through a hole or opening 436 in the body 140A. Portions of the body 140 A are indicated with dashed lines and portions of the cover 310 are indicated with full lines.

Returning to figure 4B, the body 140 may also be arranged with a rim 440 which extends at least partially around the circumference of the cover 310 when mounted. Such a rim 440 has a benefit in that it provides for a guide when attaching the cover 310 to the body 140 A and also in that it provides for a smooth surface transition between the body 140 A and the cover 310 when the cover is mounted. This both improves the aesthetic appearance of the robotic work tool and also further prevents dirt to come in under the cover 310 as it provides for a snug fit between the cover 310 and the body 140 A.

In figure 4B design details or features, such as support structures 450 are also visible. Such features or details will be covered from a visible inspection when the cover 310 is attached. The body 140A also comprises one or more, in this example, two openings 360 for receiving a connector, key or key panel, and/or display or display panel.

The arrangement as disclosed herein thus provides for a manner of updating a robotic work tool without removing the entire body which would expose components and/or cabling to the user and the outer environment which could lead to damages being incurred.

Furthermore, should a user not be able to attach the cover correctly, this will most likely not affect the operation of the robotic work tool, and the manner taught herein can thus be used by a private user for updating his/her robotic work tool - be it to replace a broken and/or scratched cover or to customize his/her robotic work tool - without having to contact a service technician or have mechanical experiences himself.

The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims.

Claims

1. A robotic work tool system (200) comprising a robotic work tool (100), said robotic work tool (100) comprising a housing (140) comprising a chassis (140B) adapted to carry at least one component (110, 120, 180, 170, 165, 160, 150), and a body (140A), wherein said body (140A) is adapted to be fitted with an exchangeable cover (310), which exchangeable cover (310) is arranged to be attached to said body (140 A) through releasable attachment means (410, 415, 420, 425, 430, 435).

2. The robotic work tool system (200) according to claim 1, wherein said body (140A) is arranged to operate as part of a lift or collision detection.

3. The robotic work tool system (200) according to claim 1 or 2, wherein said body (140A) is arranged to cover said at least one component (110, 120, 180, 170, 165, 160, 150).

4. The robotic work tool system (200) according to any of claims 1 to 3, wherein said releasable attachment means (410, 415, 420, 425, 430, 435) comprises at least one hook and slot attachment means (410, 415) for simple attachment and removal of said cover (310) by guiding a hook (410) into a slot (415).

5. The robotic work tool system (200) according to claim 4, wherein said hook and slot attachment means (410, 415) are arranged in opposing pairs, one hook and slot attachment means (410, 415) arranged at a first end and a second hook and slot attachment means (410, 415) arranged at a second, opposing end of the cover (310) and the body (140 A) respectively.

6. The robotic work tool system (200) according to any of claims 1 to 6, wherein said releasable attachment means (410, 415, 420, 425, 430, 435) comprises at least one clip or cover-to-enclose attachment means (420, 425) arranged at a mid- section of the cover (310) and the body (140A) respectively for securing said cover (310) to said body (140A).

7. The robotic work tool system (200) according to any of claims 1 to 6, wherein said releasable attachment means (410, 415, 420, 425, 430, 435) comprises at least one friction-based attachment means (430, 435).

8. The robotic work tool system (200) according to any of claims 1 to 7, wherein said releasable attachment means (410, 415, 420, 425, 430, 435) are arranged with a releasable attachment means (410, 415, 420, 425, 430, 435) arranged on the cover (310) and a corresponding releasable attachment means (410, 415, 420, 425, 430, 435) arranged on the body (140A).

9. The robotic work tool system (200) according to any of claims 1 to 8, wherein said body (140A) is all-encompassing when arranged on the chassis (140B), possibly in combination with any connector, key or keypad, and/or display or display panel arranged on the chassis (140B).

10. The robotic work tool system (200) according to any of claims 1 to 9, wherein said robotic work tool is a robotic lawnmower.

11. A cover adapted to be releasably attached to a body (140A) of a robotic work tool (100) by use of releasable attachment means (410, 415, 420, 425, 430, 435).

12. The cover (310) according to claim 11, wherein said releasable attachment means (410, 415, 420, 425, 430, 435) comprises at least one hook and slot attachment means (410, 415) for simple attachment and removal of said cover (310) by guiding a hook (410) into a slot (415).

13. A robotic work tool (100) comprising a body (140 A) which is adapted to receive a cover (310) according to claim 11 or 12, said body (140A) comprising corresponding releasable attachment means (415, 425, 435).

14. The robotic work tool (100) according to claim 13, wherein the body (140A) is adapted to receive a cover (310) according to claim 12, said body (140A) comprising corresponding hook and slot releasable attachment means (410, 415).