Hand-held power tool comprising light-emitting unit and light-emitting unit therefor

Abstract

The invention relates to a hand-held power tool (10) comprising a tool housing (12) and a lighting unit (100) releasably attachable to the tool housing (12) such that a working area (102) on which a working element (38) works is illuminated during intended use of the power tool (10). The light emitting unit (100) comprises: a light source (104); a switching element (108); an energy storage device (110); an outer housing (112) in which the light source (104), the switching element (108) and the energy storage device (110) are located; wherein the light-emitting unit (100), after being detached and removed from the tool housing (12), can be operated as a self-sufficiency unit in order to illuminate areas other than the working area (102) of the working element (38) and / or to illuminate the working area (102) from other incident directions and / or angles different from the viewing angle of a user of the power tool (10) during a predetermined use of the power tool (10).

Description

Technical Field

[0001] The invention relates to a handheld power tool, comprising a tool housing and a motor located therein, and a tool shaft having a rotation axis, which is driven by the motor during operation so that the tool shaft performs a rotational movement about its rotation axis. In addition, the power tool comprises a working element, which is attached to the distal end of the tool shaft and performs a working movement about the rotation axis of the tool shaft during operation of the motor, and a light unit, which is releasably attached to the tool housing so that a working area where the working element works is illuminated during the intended use of the power tool.

[0002] In addition, the present invention also relates to a lighting unit, which includes at least one light source suitable for emitting light; and a switch unit suitable for switching the lighting unit between an on state and an off state, in which the at least one light source emits light, and in which the at least one light source does not emit light; and an energy storage device suitable for storing electrical energy and suitable for supplying electrical energy to the at least one light source when the lighting unit is in the on state; and an external housing, in which the at least one light source is installed in a manner to emit light toward an area outside the external housing, and the switch unit is installed in a manner that a user can operate from the outside of the external housing. The lighting unit can be operated as a self-sufficient device. Background Art

[0003] Hand-held power tools of the above type are known, for example from US2008 / 122302 A1. This prior art discloses a pneumatic power tool comprising a power generation device for generating electrical energy from moving parts of the pneumatic power tool and supplying the electrical energy generated during the operation of the pneumatic power tool to an electric component of the power tool. The electric component may include a light-emitting unit that can be releasably connected to the tool housing so as to illuminate the working area where the working element works during the intended use of the power tool. The light-emitting unit includes one or more light sources, but has no energy storage device for electrical energy. The electrical energy required for the operation of the light source is directly provided by the generator of the power tool through the conductive tool housing. For this purpose, the detachably attachable light-emitting unit must not only be mechanically connected to the power tool, but also be electrically connected to the power tool. In addition, after the light-emitting unit is separated and removed from the power tool, the light-emitting unit no longer works because there is no longer any electrical energy supply.

[0004] The light-emitting unit known from US2008 / 122302A1 can only illuminate the working area from a direction and incident angle that roughly corresponds to the direction and angle of sight of the power tool user during the intended use of the power tool. This may be sufficient for pneumatic wrenches, but for other power tools and in other cases, it may be necessary to illuminate the working area from other directions and / or other angles. For example, when a polishing or grinding power tool is used to polish or grind a working area, if the direction and / or angle of light irradiating the working area is different from the direction and angle of sight of the user when using the power tool, the user can more easily and clearly see stains, scratches, bumps and irregularities on the surface to be polished or polished. If the direction in which light irradiates the working area is substantially opposite to the direction of sight of the user when using the power tool, the user can more easily and clearly see stains, scratches and bumps on the surface to be polished or polished.

[0005] Of course, this can also be achieved with the power tool known from US2008 / 122302A1 by lifting the power tool from the work area, while still keeping the pneumatic motor running so that electrical energy continues to be generated for the operation of the light-emitting unit, rotating the power tool about 180° around a substantially vertical axis, and facing the front of the power tool towards the user, at a distance from the user's body. In this way, the work area can be illuminated by the light-emitting unit of the power tool in a direction substantially opposite to the direction in which the user observes the work area. However, this is obviously very laborious and energy-consuming, not to mention the dangers to the user of the power tool continuing to operate in order to generate electrical energy to operate the light-emitting device.

[0006] On the other hand, self-sufficient lighting devices in the form of flashlights are also known in the art. These devices comprise an outer housing with one or more light sources, a battery located in the housing and a switch element for selectively switching the light sources on and off. These flashlights can be either hand-held by the user or fixed to a bicycle handlebar or the like by means of an elastic band or a belt. When connected to a bicycle handlebar or the like, the lighting unit is provided with a corresponding adapter element, which corresponds to the cylindrical shape of the handlebar portion and is located between the outer housing of the lighting unit and the handlebar.

[0007] These known bicycle flashlights or headlights have several disadvantages: Due to the bright light required when using the flashlight as a bicycle headlight, they are relatively large, heavy and bulky. This is not a problem if they are simply fixed to the handlebars of a bicycle. However, if such a flashlight is mounted on a power tool in order to illuminate the working area when the power tool is in use, this results in a more bulky and, in particular, unbalanced power tool, since most of its weight falls on the front of the power tool, and may also result in greater vibrations for the user of the power tool. Furthermore, the vibrations generated during use of power tools, in particular orbital polishing and grinding power tools, place particularly high demands on a possible connection of the light-emitting device to the tool housing, which are not met by the known belts or straps and adapter elements. Due to the strong vibrations generated during use of the power tool, it is necessary to connect the light-emitting element to the tool housing, which must be particularly strong and vibration-resistant.

[0008] Another disadvantage of the known light units is that, once they are connected in one way or another to the tool housing, they tend to become a foreign object on the tool housing, since the shape of the outer housing is usually not adapted to the outer shape of the tool housing. This is disadvantageous not only from an aesthetic point of view, but also from a practical point of view, since the light unit attached to the tool housing makes the power tool heavier and larger, which makes it more difficult to reach narrow and inclined areas to operate the working elements.

[0009] Finally, it should be emphasized that the lighting units used to illuminate the working area of ​​power tools, in particular polishing or grinding power tools, are very special devices. They are specially designed for this special application in terms of the size and manageability of the lighting units, the brightness and color of the light, and the shape of the light beam. These requirements cannot be met by known bicycle headlights, for example. Summary of the invention

[0010] Starting from the above-mentioned prior art, the object of the present invention is to improve the known power tool so that it has a lighting unit, which is configured to illuminate the working area of ​​the working element of the power tool when attached to the tool housing, and the lighting unit can be separated from the tool housing and can be used as a self-sufficient unit after being separated from the tool housing.

[0011] In order to solve this problem, a power tool is proposed which is composed of the features described in claim 1. In particular, starting from the handheld power tool defined above, it is suggested that the light emitting unit comprises:

[0012] at least one light source for emitting light toward a working area when the light emitting unit is attached to the tool housing,

[0013] a switch element for switching the light-emitting unit between an on state and an off state, wherein the at least one light source emits light in the on state and does not emit light in the off state, an energy storage device for storing electrical energy and supplying electrical energy to the at least one light source when the light-emitting unit is in the on state, and

[0014] an outer housing, the at least one light source being located in the outer housing in such a manner that it emits light toward a working area when the light emitting unit is attached to the tool housing, the switch unit being located in the outer housing in such a manner that a user can operate it from outside the outer housing when the light emitting unit is attached to the tool housing, and the energy storage device being located in the outer housing,

[0015] Wherein, the light unit, after being separated and removed from the tool housing, can be operated as a self-sufficient unit to illuminate areas outside the working area of ​​the working element during the intended use of the power tool and / or illuminate the working area from other directions and angles of incidence than the perspective of the power tool user. Preferably, the removed light unit is held and directed by the power tool user to illuminate the desired area in the desired direction and angle.

[0016] The light emitting unit emits a substantially white light to illuminate the working area of ​​the working element or any other desired surface area near the working area. When attached to the tool housing, the lighting direction and angle of the light emitting unit to illuminate the working area substantially correspond to the direction and angle of sight of the power tool user during the intended use of the power tool. When attached to the tool housing, the energy storage device can be charged using current from the power tool directly through electrical contacts or contactless, for example, by inductive or capacitive charging or the like. When attached to the tool housing, the entire outer shell of the light emitting unit or at least one light source or an optical element in the light path between at least one light source and the illuminated working area can be adjusted so as to accurately guide the light beam emitted by the light emitting unit to the desired area within or near the working area. When attached to the tool housing, the cross-sectional shape of the emitted light beam can be adjusted to a desired shape. In addition, it is also conceivable that the light emitting unit can change the intensity and / or color of the emitted light.

[0017] The user of the power tool can easily separate and remove the light unit from the tool housing. In particular, the light unit can be easily separated even if the user is wearing gloves. For this purpose, it is recommended that the user grasp the outer shell of the light unit, thereby automatically releasing the releasable connection between the outer shell and the tool housing. In this way, the user can hold and guide the light unit in the hand to illuminate the working area or other desired areas near the working area in a direction and / or angle different from the direction and angle of the user's line of sight when using the power tool. In particular, the user can easily adjust the light unit to a position and direction so that it illuminates the working area in a direction substantially opposite to the direction of the user's line of sight during the intended use of the power tool. In particular, if the irradiation direction is substantially opposite to the direction of the user's line of sight when using the power tool, and the light illuminates the working area or any other desired area near the working area, the user can more easily and clearly see stains and scratches and uneven places on the surface to be polished or polished.

[0018] Since the energy storage device is located in the outer housing of the light emitting unit, the at least one light source can still emit light for a long time after being separated from the power tool. The user can calmly check the working area and consider possible measures to remedy the deficiencies of the working area or the surface to be polished or ground, respectively.

[0019] The light unit is relatively small and lightweight, so that the power tool can be used in confined and inclined spaces even after the light unit is mounted on the tool housing. Furthermore, this ensures that the user is not made more difficult to use the power tool by the added weight and local size of the light unit on the tool housing.

[0020] Preferably, in the case of a handheld or mobile polishing or grinding power tool, the working elements are divided into two main types. The first type of working element comprises an eccentric element and a backing pad. The backing pad has a bottom surface for releasably attaching the grinding or polishing component thereto. The upper surface of the backing pad comprises a cylindrical pin, which is retained in the eccentric element in a manner that allows free rotation around a second axis of rotation of the cylindrical pin, the second axis of rotation being substantially parallel to and at a distance from the axis of rotation of the tool shaft. Opposite the backing pad, the eccentric element comprises an attachment area, through which the eccentric element can be attached to the tool shaft, preferably in a torque-proof manner, i.e., torque around the axis of rotation can be transmitted from the tool shaft to the eccentric element. The attachment area can comprise a cylindrical pin for insertion into a hole on the distal end of the tool shaft, or a groove for receiving the distal end of the tool shaft.

[0021] The second type of working element comprises only a backing pad having a bottom surface configured for releasably attaching a grinding or polishing component. The upper surface of the backing pad comprises an attachment area by which the backing pad can be connected to the tool shaft, preferably in a torque-proof manner, i.e. torque about the axis of rotation can be transmitted from the tool shaft to the backing pad. The attachment area may comprise a cylindrical pin for insertion into a hole on the distal end of the tool shaft, or a groove for receiving the distal end of the tool shaft.

[0022] It is recommended that the at least one light source comprises a light emitting diode (LED) or any other type of semiconductor light source. The advantages of such light sources are long service life and low energy consumption. There are many types of light emitting diodes with different physical and optical properties. In particular, there are many types of LEDs with different operating voltages and currents, light intensities and light colors, and they are inexpensive. When one or more light emitting diodes are used as light sources, the lighting device also includes an operating device (ballast) or a driver.

[0023] In an LED, current can only flow in one direction (diode). When heat is generated, the current increases, and the power consumption of the light-emitting diode also increases, resulting in further heating. Therefore, effective cooling of the light-emitting element is recommended.

[0024] It is conceivable that, during the intended use, the light emitting unit generates a cooling airflow in the tool housing for cooling the components of the power tool. To this end, the air outlet in the tool housing can be arranged near or below the outer shell of the light emitting unit connected to the tool housing. The cooling airflow leaving the tool housing through the air outlet can sweep along the outer shell or enter the outer shell through corresponding air inlets on the outer shell. These air inlets can even be arranged on the side of the outer shell facing the tool housing when the light emitting unit is connected to the tool housing.

[0025] Furthermore, the energy storage device can also include batteries, preferably rechargeable batteries. One or more conventional batteries can be accommodated in a receiving container within the outer housing. The receiving container can be closed with a container cover. The batteries can be removed from the receiving container, possibly after opening the container cover, and then replaced with new batteries. If necessary, one or more rechargeable batteries can also be provided in such a receiving container and replaced with fully charged batteries. In addition, the outer housing can also be equipped with a socket element to which a charger can be connected in order to charge the batteries in the receiving container.

[0026] When the light unit is releasably attached to the tool housing, the battery can also be charged with the aid of electrical energy from the power tool. The battery can be charged by electrical contact or contactless means, for example by inductive or capacitive charging or the like. For this purpose, inductive or capacitive charging elements are provided in the tool housing and in the outer housing of the light unit, respectively.

[0027] Furthermore, it is also recommended that the outer housing of the light unit is made of a plastic material. Plastic materials are strong and durable enough to withstand the hard work of power tools, in particular polishers or grinders. In addition, plastic materials can also absorb shocks or impacts well, thus preventing the light unit and its outer housing, respectively, from being damaged. In addition, plastic materials are also resistant to moisture, acidic substances, etc.

[0028] Additionally or alternatively, the outer shell of the light emitting unit is conformed to a portion of the tool housing so that a detachable connection between the light emitting unit and the tool housing is achieved by a shape-fit connection between the outer shell of the light emitting unit and a portion of the tool housing. To this end, the outer shell of the light emitting unit can be clamped and locked into an aligned position on the tool housing by a specific semi-rigid structure of the outer shell or a portion thereof. The outer shell or a portion thereof can be formed into a cuff or sleeve. The cuff or sleeve can surround at least a portion of the tool housing and, due to the elasticity of the cuff or sleeve material, can be fixed to the tool housing by clinging or clamping the tool housing.

[0029] In particular, it is recommended to mount the light unit at the front of the tool housing. For example, in the case of an angle polisher or a grinder, the front is considered to be that part close to the housing where the axis of rotation of the tool shaft intersects the longitudinal axis of the motor shaft or an intermediate shaft located between the motor shaft and the tool shaft.

[0030] According to a preferred embodiment, when the light-emitting unit is connected to the tool housing, the contact surface of the outer shell of the light-emitting unit is in full contact with the outer surface of the tool housing. Preferably, this means that the entire contact surface of the outer shell is completely located on the correspondingly designed surface of the tool housing. This ensures a stable and firm connection between the light-emitting unit and the tool housing. The contact surface preferably has a three-dimensional extension. When the external contact surface of the light-emitting unit and the contact surface of the tool housing are in contact with each other, the position of the light-emitting unit relative to the tool housing is limited to at least two planes extending perpendicularly to each other, for example, in the xy plane and the xz plane of a Cartesian coordinate system. Preferably, the contact surface is designed so that when the contact surface of the outer shell of the light-emitting unit and the contact surface of the tool housing are in contact with each other, the position of the light-emitting unit relative to the tool housing is determined in all three planes extending perpendicularly to each other.

[0031] According to a further preferred embodiment, the releasable connection between the light emitting unit and the tool housing is achieved by a snap connection between the outer housing of the light emitting unit and the tool housing. Additionally or alternatively, the releasable connection between the light emitting unit and the tool housing may also be achieved by interacting magnetic elements provided in or on the outer housing of the light emitting unit and in or on the tool housing. The magnetic element may comprise one or more permanent magnets and / or one or more ferromagnetic elements.

[0032] According to a further preferred embodiment, it is suggested that the three-dimensional shape of the outer shell of the light unit is adapted to the outer shape of a part of the tool housing, and the light unit is releasably mounted on the part of the tool housing in such a way that the outer shell of the light unit is flush with the adjacent surface of the tool housing when the light unit is mounted on the tool housing. For example, the front of the tool housing may have a depression, an inward protrusion or a groove. At least a part of the outer shell of the light unit coincides with the depression, protrusion or groove. The wall of the outer shell is connected to the adjacent surface of the tool housing without a step and preferably without a kink.

[0033] It is further proposed that the light-emitting unit comprises an acceleration sensor configured to sense vibrations of the power tool when the light-emitting unit is connected to the tool housing, and to determine the operating state of the power tool based on the sensed vibration amplitude. In particular, the sensor is configured to detect the on state and / or off state of the power tool. Although attempts are made to reduce or even compensate for vibrations during the intended use of the power tool, the operation of the tool motor and the rotation of the working element around the axis of rotation of the tool shaft inevitably lead to some vibrations, which are also transmitted to the tool housing and can be sensed on the tool housing. Preferably, at least one vibration / acceleration threshold is defined, and if the vibration / acceleration exceeds the threshold, the power tool is considered to be in the on state, and if the vibration / acceleration is below the threshold, the power tool is considered to be in the off state. After the vibration / acceleration exceeds or falls below the threshold, the operating state can be determined with a time delay. In addition, the sensed vibration / acceleration can be filtered and the operating state can be determined based on the filtered value.

[0034] The determined operating state of the power tool can be used for many different tasks, including assessing the proper function of the power tool, installing the correct backing pad and / or polishing or grinding parts, etc. The light-emitting unit can be configured to automatically drive a switching element so as to switch the light-emitting unit between an on state and an off state depending on the sensed vibration amplitude. Thus, the sensed vibration / acceleration and / or the determined operating state of the power tool can be used to turn on or off the at least one light source of the light-emitting unit. The advantage of this is that the working area is automatically illuminated when the power tool is started and intended for use. Then, after the power tool is turned off, the lighting of the working area is also interrupted or stopped. After the vibration / acceleration exceeds or falls below a threshold value, the light source can be activated and / or turned off by a delay time.

[0035] Finally, it is proposed that the lighting unit comprises a radio communication device which transmits a radio signal representative of the operating status of the power tool. The radio signal may be received from an external or remote component, such as a dust suction device or a vacuum cleaner for sucking dust-laden air from the grinding power tool. Upon receiving a radio signal from the lighting unit indicating that the power tool is started, the dust suction device automatically turns on. The dust suction pipe of the dust suction device may be connected to the dust suction port of the grinding power tool so as to suck dust-laden air from the working area of ​​the grinding power tool. Likewise, when the power tool is turned off again, the dust suction device receives a corresponding radio signal and automatically turns off. The time of turning off the suction device is preferably delayed with the time of receiving a corresponding radio signal indicating that the power tool is turned off. The radio signal and the data contained therein may be any communication standard currently known or yet to be developed, including WiFi, BlueTooth, ZigBee or similar standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Further features and advantages of the invention will become apparent in the embodiments described below with reference to one or more of the accompanying drawings. It should be emphasized that each feature shown in the drawings and possibly described below with reference to an embodiment may be important to the invention in itself or in another embodiment, even if it is not explicitly shown in the drawings and / or not explicitly described in the subsequent description. The accompanying drawings show:

[0037] Figure 1 A side view of a power tool according to a preferred embodiment of the present invention;

[0038] Figure 2 for Figure 1 A top view of the power tool;

[0039] Figure 3 A vertical cross-sectional view of a tool head of a power tool according to another preferred embodiment of the present invention;

[0040] Figure 4 A three-dimensional side view of a tool head of a power tool according to another preferred embodiment of the present invention;

[0041] Figure 5 A perspective front view of a tool head of a power tool according to another preferred embodiment of the present invention;

[0042] Figure 6 It is a vertical sectional view of a tool head of a power tool according to another preferred embodiment of the present invention. DETAILED DESCRIPTION

[0043] Figure 1 and Figure 2A side view and a top view of a hand-held and / or hand-guided power tool 10 as a polishing device or polisher are shown respectively. In addition, according to the present invention, the power tool 10 can also be a sanding machine or a polishing machine, or even an electric drill or a cordless screwdriver.

[0044] The polishing machine 10 includes a housing 12, which is mainly composed of two parts, namely a rear portion 12a and a front portion 12b. In more detail, the housing 12 includes a rear portion 12a, a distal component 12c, a front portion 12b and a front housing 12d. The rear portion 12a is preferably made of a hard plastic material. Of course, the rear portion 12a of the housing 12 can also be made of different hard materials, such as metal or carbon fiber. In addition, the rear portion 12a of the housing 12 can also include some areas, which are made of elastic materials such as soft plastic or rubber to ensure that the user can safely and comfortably grasp, hold and guide the power tool 10. The rear portion 12a of the housing 12 is preferably divided into two half shells by a substantially vertical plane, and the two half shells are connected to each other along the vertical plane and fixed together by screws 14.

[0045] The rear portion 12a of the housing 12 includes an actuating lever 16 that cooperates with a switch (not shown), preferably located within the housing 12, for turning the polishing machine 10 on and off. The actuating lever 16 may include a blocking mechanism 18 for preventing inadvertent activation of the tool 10. The actuating lever 16 is rotatable about a rotation axis 20 extending perpendicular to the longitudinal direction of the housing 12. Figure 1 and Figure 2 In the illustrated embodiment, the actuating lever 16 is located on the top side of the housing 12. Of course, the lever 16 may also be mounted on the bottom surface of the housing 12. In addition, one or more buttons or rotary switches may be used instead of the lever 16 to turn the power tool 10 on and off.

[0046] In addition, Figure 1 and Figure 2 In the embodiment of the present invention, the rear portion 12a of the housing 12 is provided with a rotating wheel 22 for adjusting the speed of the tool motor 24. The rotating wheel 22 can be used in conjunction with a potentiometer (not shown), which is preferably located inside the housing 12. Of course, the actuating lever 16 or one or more buttons or rotary switches can also be combined with the functions of turning the motor 24 on and off and adjusting the speed of the motor 24. In this case, the rotating wheel 22 can be omitted. In addition, the rotating wheel 22 can be set on the side of the housing 12 instead of Figure 1 and Figure 2 Top shown.

[0047] The distal end 12c of the rear portion 12a can be removed from the rest of the housing 12 so that the battery 26 can be removed from the interior of the rear portion 12a of the housing 12. The battery 26 provides electrical energy for the operation of the polisher 10 and its electronic components. Of course, the polisher 10 can also be powered by mains electricity. In this case, the battery 26 is not required, and the receiving container of the battery 26 in the housing 12 can be used to accommodate a transformer and other circuits to convert the mains voltage (such as 100V or 250V AC, 50Hz or 60Hz) to the operating voltage (such as 12V, 18V or 24V DC) of the electronic components of the polisher 10.

[0048] The distal end 12c of the housing 12 can be fixed to the rear portion 12a by a snap connection, and the snap connection includes two opposite side snap release buttons 28 for releasing the snap connection. In order to remove the rear end 12c from the rear portion 12a of the housing 12, the side snap release button 28 can be pressed to release the snap connection, so that the rear end 12c of the housing 12 is separated from the rear portion 12a, and the battery 26 is removed from the housing 12. The distal end 12c of the housing 12 can be fixedly connected to the battery 26, or it can be a separate cover for independently closing the accommodating cavity of the battery 26.

[0049] The rear portion 12a of the housing 12 may be provided with a plurality of cooling vents 30 of any shape and extent to direct airflow from the interior of the housing 12 to the environment and cool the electronic components located within the housing 12 during operation of the power tool 10 .

[0050] The front portion 12b of the housing 12 is substantially tubular and is adapted to receive and guide the drive shaft 32, for example, via one or more bearings 86 (see FIG. Figure 3 and Figure 6 ) so that it rotates around the rotation axis 34. The drive shaft 32 is driven by the motor 24. To this end, the drive shaft 32 can be integral with the motor shaft or connected to the motor shaft in a torque-proof manner. The tubular front part 12b is preferably made of metal (such as aluminum) or a hard plastic material. The front part 12b preferably has a circular cross-section. The front part 12b can be releasably connected to the rear part 12a of the housing 12 by means of threaded connection or screws. It is also possible to simply clamp the rear end of the front part 12b between the two half shells that constitute the rear part 12a of the housing 12. The two half shells are fixed together by means of screws 14, etc., and the front part 12b can be fixed to the rear end part 12a of the housing 12. Alternatively, the front part 12b is integral with the rear part 12a. In particular, it is conceivable that the front part 12b also includes two half shells, each of which can be integral with the respective half shells of the rear part 12a of the housing 12. In this case, the material of the front part 12b is the same as that of the rear part 12a of the housing 12.

[0051] The motor 24 is located in the rear portion 12a of the housing 12, and is preferably a brushless (BL) motor, particularly a brushless direct current (BLDC) motor. In addition, a first gear mechanism (not shown) may be provided between the motor shaft and the drive shaft 32, which may set a certain transmission ratio between the rotational speed of the motor shaft and the rotational speed of the drive shaft 32. Depending on the design of the gear mechanism, the transmission ratio may be 1, greater than 1, or less than 1. Typically, the transmission ratio is greater than 1 to reduce the rotational speed of the drive shaft 32 relative to the rotational speed of the motor shaft and to increase the torque that the drive shaft 32 can provide.

[0052] The power tool 10 may include a second gear mechanism 42 (see Figure 3 and Figure 6 ), for converting the rotational motion of the drive shaft 32 around the rotational axis 34 into the rotational motion of the tool shaft 36 of the power tool 10 around another rotational axis 40. The angle α at which the two rotational axes 34 and 40 intersect is approximately between 70° and 110°, in particular, about 90°. Figure 1 and Figure 2 In the embodiment of the present invention, the angle α between the two rotation axes 34 and 40 is approximately 98°. The tool shaft 36 drives a working element 38 of the power tool 10 .

[0053] The front end of the drive shaft 32, the second gear mechanism 42 and the tool shaft 36 are preferably located in a tool head 44, which is connected to the front end 12e of the front portion 12b of the tool housing 12. The tool head 44 preferably includes a tubular front housing 12d for receiving and guiding the tool shaft 36, for example, through one or more bearings 88 (see Figure 3 and Figure 6 ) so that it rotates around the rotation axis 40. The cross section of the front sleeve 12d can be circular. The diameter of the circular cross section of the front housing 12d is preferably substantially the same as the diameter of the circular cross section of the front part 12b. The tool head 44 or the front housing 12d is preferably a component of the front part 12b of the housing 12. It is preferably made of the same material as the tubular front part 12b. The protective cover 46 is connected to the bottom end of the tubular front housing 12d and surrounds at least a portion of the working element 38, such as the eccentric element 54 (see Figure 3 and Figure 6 ) or an extension rod (not shown) that connects the distal end of the tool shaft 36 to the back pad 48 of the working element 38.

[0054] from Figure 3 and Figure 6 As can be seen in the figure, the second gear mechanism 42 can include a bevel gear arrangement with two meshing bevel gears 50 and 52. One bevel gear 50 can be connected to the drive shaft 32 or formed integrally therewith. The other bevel gear 52 can be connected to the tool shaft 36 or formed integrally therewith. The transmission ratio of the bevel gear arrangement 42 can be greater than 1, less than 1, or equal to 1.

[0055] Different from the above, the first and second gear mechanisms can also be designed as a single gear mechanism, located in the front portion 12b between the motor shaft and the drive shaft 32, or located in the tool head 44 between the drive shaft 32 and the tool shaft 36. In this case, the transmission ratio of the single gear mechanism is preferably ≠ 1. In addition, according to the present invention, the power tool 10 may also not include a gear mechanism at all, in which case the tool shaft 36 will rotate around the same rotation axis as the motor shaft and the drive shaft 32 (if any).

[0056] In addition, a printed circuit board (PCB) may be mounted within the housing 12 and may include electrical and electronic circuits and components that together form at least a portion of the control unit. The control unit preferably includes a microcontroller and / or microprocessor for processing a computer program that is programmed to perform the desired motor control functions when the program is processed on the microprocessor.

[0057] Unlike the above, the power tool 10 may also be equipped with a pneumatic motor instead of the electric motor 24. In this case, pressurized air may be delivered to the power tool 10 through an air inlet and supplied to the pneumatic motor through appropriate pipes or ducts.

[0058] from Figure 3 and 6 As can be further seen in the figure, the first type of working element 38 can include an eccentric element 54 and a backing pad 48. The backing pad 48 has a bottom surface 56, and the grinding or polishing member 144 (see Figure 6 ) is detachably attached thereto, for example by means of Attachment. The sanding element may include a paper, fabric, or plastic film having abrasive particles embedded in its bottom surface and a corresponding adhesive layer on its top surface for releasable attachment to the bottom surface 56 of the backing pad 48. The polishing element may include a pad having a sponge or foam material on its bottom surface, natural or synthetic wool, microfiber, or the like, and a corresponding adhesive layer on its top surface for releasable attachment to the bottom surface 56 of the backing pad 48.

[0059] The top surface of the backing pad 48 comprises a cylindrical pin 58 which is held in the eccentric element 54 by means of a bearing 62 in a freely rotatable manner about an axis of rotation 60 of the cylindrical pin 58. The axis of rotation 60 is substantially parallel to the axis of rotation 40 of the tool shaft 36 and is spaced therefrom. Figure 3 and Figure 6 In the embodiment shown, the spindle 90 is held in the bearing 62 in a manner that allows it to rotate freely about the rotation axis 60. The cylindrical pin 58 is connected to the distal end of the spindle 90 by means of a threaded connection or the like. Figure 3 and Figure 6In the embodiment, the cylindrical pin 58 is indirectly held in the bearing 62 via the spindle 90. However, it is also conceivable that the cylindrical pin 58 forms an integral part of the spindle 90, in which case the backing pad 48 will be directly held in the bearing 62. The backing pad 48 is preferably made of a hard plastic material, metal or the like.

[0060] Opposite the backing pad 48, the eccentric element 54 comprises a further cylindrical pin 64, which has at least one radial groove 66 on its outer circumferential surface. The further cylindrical pin 64 can be designed to be separate from the eccentric element 54 and connected to the eccentric element 54 in a torque-proof manner, for example by a threaded connection, a crimped connection, welding or the like. In the present invention, "torque-proof" means that torque can be transmitted from the further cylindrical pin 64 to the eccentric element 54. However, it is also conceivable that the cylindrical pin 64 forms an integral part with the eccentric element 54. The further cylindrical pin 64 is preferably made of a ferromagnetic material, such as steel or any other suitable metal, or a hard plastic material. The eccentric element 54 can also be made of metal or a hard plastic material.

[0061] A second type of working element, not shown in the figures, may include only a backing pad 48 having a bottom surface 56 for releasably attaching a grinding or polishing component thereto. The top surface of the backing pad 48 includes a cylindrical pin 58 having at least one radial groove on its outer circumferential surface. The cylindrical pin 58 is preferably made of a ferromagnetic material, such as steel or any other suitable metal, or a plastic material. In this case, the eccentric element is omitted and the backing pad 48 is directly connected to the distal end of the tool shaft 36. The cylindrical pin 58 is preferably made of a ferromagnetic material ... Figure 3 and Figure 6 The pin 58 shown has a longer axial extension. The cylindrical pin 58 will form a kind of extension rod. Alternatively, a separate extension rod can be installed between the distal end of the tool shaft 36 and the cylindrical pin 58.

[0062] exist Figure 3 and Figure 6 In the embodiment shown, the tool shaft 36 has an axial bore 68 for receiving a further cylindrical pin 64 of a first type of working element 38 or a cylindrical pin 58 of a second type of working element 38. The bore 68 is radially delimited by a hollow cylindrical sleeve 78, which is an integral part of the tool shaft 36. At least one locking element 70 is fixed in the hollow cylindrical sleeve 78 in a radially movable manner. Figure 3 and Figure 6, only one locking element 70 located on the right side of the rotation axis 40 is shown, while the other locking element on the left side is omitted, in order to facilitate the understanding of the design and function of the axial fixing device 80. In particular, on the left side of the rotation axis 40, where the other locking element 70 is located, the retaining receiving portion 72 of the other locking element 70 can be seen. The retaining receiving portion 72 has a radial extension so that the locking element 70 moves in the radial direction. In addition, the retaining receiving portion 72 can also be designed so that the locking element 70 does not fall off when the cylindrical pin 58 or the further cylindrical pin 64 of the working element 38 is removed from the hole 68.

[0063] In other embodiments, the cylindrical pin 58 or the additional cylindrical pin 64 of the working element 38 may have an axial hole, into which the tool shaft 36 may be inserted in the axial direction.

[0064] Generally speaking, Figure 3 and Figure 6 The power tool 10 shown has an axial retaining device 80, which is configured to retain the working element 38 relative to the tool shaft 36 when the working element 38 is releasably connected to the tool shaft 36 from the outside of the tool housing 12 in an axial extension direction parallel to the rotation axis 40 of the tool shaft 36. However, other types of connecting and retaining the working element 38 at the distal end of the tool shaft 36 are also conceivable, whether they are currently known or not.

[0065] On the one hand, at least one locking element 70 or, on the other hand, the cylindrical pin 58 or the other cylindrical pin 64 in and / or around the at least one radial groove 66 is made of a magnetic material. At least one locking element 70 or the other of the cylindrical pins 58, 64 in and / or around the at least one radial groove 66 is made of a magnetic material or a ferromagnetic material. This results in a magnetic interaction between the at least one locking element 70 and the at least one radial groove 66. When the working element 38 is connected to the tool shaft 36, the at least one locking element 70 is automatically held in the locked position and in the at least one radial groove 66 under the action of the magnetic force, thereby mechanically engaging with the at least one radial groove 66 and thereby holding the working element 38 relative to the tool shaft 36 in the axial direction.

[0066] The axial retaining device 80 may include a discrete radial groove 66 for each locking element 70, each radial groove 66 being configured to receive a respective locking element 70 when in the locked position. Alternatively, the axial retaining device 80 may include a single annular radial groove 66 that is configured to receive all of the locking elements 70 when the locking elements 70 are in the locked position.

[0067] The locking element 70 may be spherical. However, other shapes, such as a cube, may also be used. The radial cross-sectional shape of at least one radial groove corresponds to the shape of the locking element 70.

[0068] In order to evenly distribute the clamping force acting between the tool shaft 36 and the working element 38, it is recommended that the axial retaining device 80 includes at least two, preferably at least three, and in particular at least four locking elements 70, and when the working element 38 is connected to the tool shaft 38, the locking elements 70 are equidistantly positioned in the circumferential direction of the rotation axis 40 of the tool shaft 36.

[0069] Unlike what is shown in the figures, instead of moving and holding the locking element 70 in its locking position and in at least one groove 66 by a radially acting magnetic force, the locking element 70 can also be moved and held in its locking position and in at least one groove 66 by a radially acting mechanical force, for example by one or more spring elements and / or a mechanical force applied by an outer ring element that can be moved axially between at least two positions, similar to the description in US2011 / 036604A1. In a first position of the outer ring element, if the working element 38 is axially connected to the tool shaft 36, the locking element 70 is forced to remain in its locking position and in at least one radial groove 66. In this position of the outer ring element, the working element 38 is held in the axial direction relative to the tool shaft 36. In a second position of the outer ring element, the locking element 70 can move freely radially and leave its locking position and at least one radial groove 66. In this position of the outer ring element, the working element 38 is no longer held in the axial direction relative to the tool shaft 36 and can be freely removed from the tool shaft 36 and the power tool 10.

[0070] Depending on the design of the working element 38 and the connection method with the distal end of the tool shaft 36, the working element 38 can perform different working motions, including rotation, random orbit (see Figure 3 ), gear drive or orbital working motion. If the working element 38 only includes a backing pad 48 directly connected to the tool shaft 36, it will perform a rotational motion. Figure 3 The free rotation of the backing pad 48 relative to the eccentric element 54 is limited or even prevented, and the backing pad 48 will perform an orbital working motion. If the working element 38 includes a gear arrangement, such as a planetary gear arrangement, between the distal end of the tool shaft 36 and the backing pad 48, a gear-driven working motion can be achieved. In the gear-driven motion, the number of rotations of the backing pad 48 about its rotation axis 60 depends on the number of rotations of the tool shaft about its rotation axis 40 and is in a fixed proportion to the number of rotations of the tool shaft about its rotation axis 40.

[0071] According to the present invention, the handheld power tool 10 includes a lighting unit 100 releasably connected to the tool housing 12 to illuminate a working area 102 where the working element 38 operates during the intended use of the power tool 10 .

[0072] In particular, it is proposed that the light emitting unit 100 comprises:

[0073] at least one light source 104 for emitting light in a direction 106 toward the work area 102 when the light unit 100 is attached to the tool housing 12,

[0074] The switch element 108 is used to switch the light emitting unit 100 between an on state and an off state. In the on state, the at least one light source 104 emits light, and in the off state, the at least one light source 104 does not emit light.

[0075] an energy storage device 110 for storing electrical energy and providing electrical energy to the at least one light source 104 when the light emitting unit 100 is in an on state, and

[0076] An external shell 112, the at least one light source 104 is located in the external shell 112 in a manner that emits light toward a working area when the light emitting unit 100 is attached to the tool housing 12, the switch unit 108 is located in the external shell 112 in a manner that a user can operate it from the outside of the external shell 112 when the light emitting unit 100 is attached to the tool housing 12, and the energy storage device 110 is located in the external shell 112.

[0077] After being separated and removed from the tool housing 12, the light unit 100 can be operated as a self-sufficient unit to illuminate surface areas outside the working area 102 of the working element 38 when the light unit 100 is held and guided by a user of the power tool 10, and / or to illuminate the working area 102 from other incident directions and angles from the perspective of the power tool user.

[0078] In order to mount the light emitting unit 100 on the tool housing 12, the tool housing 12 may provide a groove (not shown) for receiving at least a portion of the outer shell 112 of the light emitting unit 100. Viewed along the direction in which the light emitting unit 100 is inserted into the groove, the shape of the groove may be the same as the shape of the portion of the outer shell 112 received by the groove. In particular, the shape of the groove and / or the portion of the outer shell 112 received by the groove is dome-shaped, rectangular or square, with inclined or vertical side walls. The light emitting unit 100 may be retained in the groove by snap-fitting, friction or other means. To this end, it is recommended that the outer shell 112 or at least the portion of the tool housing 12 including the groove is made of an elastic material, such as an elastic plastic material, rubber or the like.

[0079] The light unit 100 emits substantially white light to illuminate a working area 102 of the working element 38 or any other desired surface area proximate to the working area 102. When connected to the tool housing 12, the light unit 100 illuminates the working area 38 in a lighting direction 106 and angle that substantially corresponds to the direction and angle of vision of a user of the power tool 10 during intended use of the power tool 10.

[0080] When connected to the tool housing 12, the energy storage device 110 can be charged from the power tool 10 directly through electrical contacts or contactlessly (e.g., by inductive or capacitive charging or the like). When connected to the tool housing 12, the entire outer housing 112 of the light unit 100, or at least one light source 104, or an optical element 114 located in the light path between the at least one light source 104 and the illuminated work area 102 can be adjusted so as to accurately direct the light beam emitted by the light unit 100 to a desired area within or near the working area 102. When connected to the tool housing 12, the cross-sectional shape of the emitted light beam can be adjusted to a desired shape. In addition, it is also conceivable that the light unit 100 can change the intensity and / or color of the emitted light.

[0081] The at least one light source 104 may include a light emitting diode (LED) or any other type of semiconductor light source. The advantages of such light sources 104 are long service life, low energy consumption, and compact design. When one or more LEDs are used as light sources 104, the lighting unit 100 preferably also includes an operating device (ballast) or a driver. The driver may include various electrical and / or electronic components and may also include a microprocessor or microcontroller. These components 128 are placed on a printed circuit board (PCB) 126 (see Figure 6 ). Components 128 may be mounted on PCB 126. A plurality of conductive tracks may be formed on printed circuit board 126 to connect components 128 to each other. At least one light source 104 is preferably in contact with the conductive tracks on printed circuit board 126 and other components 128 connected thereto. Energy storage device 110 may be electrically connected to other components 128 and at least one light source 104 via the conductive tracks. To this end, energy storage device 110 may be mounted (fixedly connected and electrically contacted) on PCB 126.

[0082] The energy storage device 110 may include batteries, preferably rechargeable batteries. One or more conventional batteries may be mounted in a receiving container within the outer housing 112. The receiving container may be closed with a container cover. The batteries may be removed from the battery compartment or removed after opening the battery compartment cover and then replaced with new batteries. If necessary, one or more rechargeable batteries may also be provided in such a receiving container and replaced with fully charged batteries. In addition, the outer housing 112 may also be equipped with a socket element for connecting a charger to charge the internal batteries.

[0083] When the light unit 100 is releasably connected to the tool housing 12, the battery can also be charged by the electrical energy of the power tool 10. The battery charging can be achieved by electrical contact or contactless means, for example, by inductive or capacitive charging or the like. For this purpose, respective inductive or capacitive charging components are provided in the tool housing 12 and in the outer housing 112 of the light unit 100, in particular in the relative position when the light unit 100 is connected to the tool housing 12.

[0084] The outer housing 112 of the light emitting unit 100 is preferably made of a plastic material, in particular an opaque plastic material. The outer housing 112 may include a light exit window, through which the light of the at least one light source 104 passes on the way to the illuminated surface area 102. The light exit window may be closed by a transparent or translucent lens cover 114. The lens cover 114 may be equipped with optical elements, such as prisms, cylindrical lenses, etc., to deflect the light passing through the lens cover 114. The optical element can focus the light passing through and guide it to the surface area 102 to be illuminated. Therefore, the lens cover 114 can constitute an optical element 114 in the light path. In addition, the lens cover 114 may also be without any optical elements. In the light path, for example, between the at least one light source 104 and the lens cover 114, more optical elements may be arranged. For example, at least one light source 104 may be associated with an optical lens, which can focus the light emitted by the LED into a 180° half space and guide it to the light exit window.

[0085] The light emitting unit 100 is mounted on a surface of the tool housing 12, preferably the top surface of the front housing 12d, and its extension direction is substantially parallel to the longitudinal extension direction of the front part 12b and the rotation axis of the motor shaft and the drive shaft 32. Relative to the extension of the top surface, the light emission direction 106 extends at a relatively large angle β, greater than 45° (see Figure 3 ), preferably greater than 60°, especially greater than 75°.

[0086] The lighting unit 100 is releasably connected to the tool housing 12 via a releasable connection 116 between the outer housing 112 and the tool housing 12. Figure 3 In an embodiment, the releasable connection 116 comprises a snap-fit ​​or latch connection between the outer housing 112 of the light unit 100 and the tool housing 12. To this end, the outer housing 112 may comprise a spring tongue 118 with a latch element 120 facing the tool housing 12, which may engage with a hole or groove on the tool housing 12, in particular the front housing 12d of the tool housing 12, when the light unit 100 is placed on the tool housing 12. Alternatively, the hole or groove may also be provided on the front end 12e of the tool housing 12. In addition, in Figure 6In the embodiment of the present invention, the releasable connection 116 includes a magnetic connection between the outer shell 112 of the light emitting unit 100 and the tool housing 12. To this end, when the light emitting unit 100 is placed on the tool housing 12, the first magnetic element 122 can be associated with the outer shell 112, and the second magnetic element 124 can be associated with the tool housing 12, in particular, with the front shell 12d of the tool housing 12. Alternatively, the second magnetic element 124 can also be associated with the front end 12e of the tool housing 12. The releasable attachment 116 can include one or more permanent magnets, which are located in or on the outer shell 112 and the tool housing 12. Alternatively, the releasable attachment 116 can include one or more permanent magnets in or on the outer shell 112 or in or on the tool housing 12, and one or more ferromagnetic elements in or on the other of the outer shell 112 and the tool housing 12.

[0087] In addition, other possible ways can be used to achieve the detachable connection between the light emitting unit 100 and the tool housing 12. For example, the outer shell 112 of the light emitting unit 100 can be shaped corresponding to a portion of the tool housing 12, so that the light emitting unit 100 can be releasably connected to that portion of the tool housing 12 through a shape-fitting connection between the outer shell 112 and the portion of the tool housing 12. To this end, the outer shell 112 can be clamped and locked to an aligned position on the tool housing 12 in a matching manner through a specific semi-rigid structure of the outer shell 112 or a portion thereof. The outer shell 112 or a portion thereof can be formed into a cuff or sleeve type. The cuff or sleeve can surround at least a portion of the tool housing 12, and due to the elasticity of the cuff or sleeve material, it can be held on the tool housing 12 by clinging to or clamping the tool housing 12.

[0088] After being removed from the tool housing 12, the user can hold and direct the light unit 100 by hand to illuminate the working area 102 or other desired areas near the working area 102 in a direction 106 and / or angle different from the direction and angle of the user's line of sight during the intended use of the power tool 10. In particular, the user can easily adjust the light unit 100 to a position and orientation so that it illuminates the working area 102 in a direction 106 substantially opposite to the direction of the user's line of sight during the intended use of the power tool 10. If the illumination direction 106 is substantially opposite to the direction of the user's line of sight during the intended use of the power tool 10, and the light is illuminated to the working area 102 or any other desired areas near the working area 102, the user can more easily and clearly see stains and scratches, as well as bumps and irregularities on the surface 102 to be polished or sanded.

[0089] Since the energy storage device 110 is located in the outer housing 112 of the light unit 100, the at least one light source 104 will emit light for a long time even after being separated from the power tool 10. The user can calmly check the working area 102 and consider possible measures to remedy deficiencies in the working area 102 or the surface to be polished or sanded, respectively.

[0090] In an LED, current can only flow in one direction (diode). As the operating temperature of the LED increases, the current and power consumption in the LED will also increase, resulting in further heating. Therefore, it is recommended to effectively cool the light emitting unit 100, especially the components within the outer housing 112.

[0091] During intended use, the light unit 100 can use a cooling airflow 130 generated inside the tool housing 12 for cooling components of the power tool 10. The airflow 130 can be directed into the interior of the outer housing 112 and used as a cooling airflow 132 for components 128 of the light unit 100 (including at least one light source 104 and an energy storage device 110). To this end, when connected to the tool housing 12, one or more air outlet openings 134 can be provided in the tool housing 12 near or below the outer housing 112 of the light unit 100. The cooling airflow 130 that leaves the tool housing 12 through the air outlet openings 134 can sweep along the outer surface of the outer housing 112 and / or enter the outer housing 112 through various air inlets on the outer housing 112. Figure 6 In the embodiment of the present invention, since the outer housing 112 has no wall facing the front end 12e of the tool housing 12, an air inlet can be provided. Alternatively, if the outer housing 112 has a wall facing the front end 12e, an air inlet corresponding to the air outlet opening 134 of the tool housing 12 can be provided on the wall. When the light emitting unit 100 is connected to the tool housing 12, the air inlet is provided on the side of the outer housing 112 facing the tool housing 12.

[0092] The light unit 100 is preferably mounted on the front part or the tool head 44 of the tool housing 12, respectively. For example, in the case of an angle grinder or a sanding machine, as shown in the power tool 10 in the figure, the front part is considered to be the part close to the tool housing 12, in which the rotation axis 40 of the tool shaft 36 intersects with the longitudinal axis 34 of the motor shaft or intermediate shaft (such as the drive shaft 32) located between the motor shaft and the tool shaft 36.

[0093] When the light emitting unit 100 is attached to the tool housing 12, it is preferred that the contact surface of the outer shell 112 of the light emitting unit 100 is in full contact with the corresponding outer surface of the tool housing 12, that is, the entire contact surface of the outer shell 112 is completely located on the corresponding shape surface of the tool housing 12. The contact surface of the outer shell 112 preferably has a three-dimensional extension. When the contact surface of the outer shell 12 of the light emitting unit 100 and the contact surface of the tool housing 12 are in contact with each other, the position of the light emitting unit 100 relative to the tool housing 12 is at least limited to two planes extending perpendicular to each other, for example, on the xy plane and the xz plane of the Cartesian coordinate system (see Figure 4 ). Preferably, the contact surface is designed so that when the contact surface of the outer shell 112 of the light emitting unit 100 contacts the contact surface of the tool housing 12, the position of the light emitting unit 100 relative to the tool housing 12 is limited to all three planes xy, xz and yz extending perpendicularly to each other.

[0094] It is recommended that the three-dimensional shape of the outer shell 112 of the light unit 100 is adapted to the outer shape of the portion of the tool housing 12 on which the light unit 100 is releasably mounted, so that when the light unit 100 is mounted on the tool housing 12, the outer shell 112 is flush with the adjacent surface of the tool housing 12. Alternatively, it is recommended that the three-dimensional shape of at least one side of the outer shell 112 of the light unit 100 continues the direction and / or extension of the adjacent surface of the tool housing 12, preferably without steps and / or kinks. For example, the front of the tool housing 12 may have a depression, an inward protrusion or a groove (see Figure 6 ). At least a portion of the outer housing 112 of the light unit 100 matches the depression, protrusion or groove. At position 136, the top sidewall of the outer housing 112 is neatly integrated with at least one adjacent surface of the tool housing 12 without steps and kinks.

[0095] The light emitting unit 100 may include an acceleration sensor 138 (see Figure 6 ), when the light emitting unit 100 is connected to the tool housing 12, the sensor is configured to sense the vibration of the power tool 10 and determine the operating state of the power tool 10 based on the sensed vibration amplitude. The sensor can be configured to detect the on state and / or the off state of the power tool 10. The operation of the tool motor 24 and the rotation of the working element 38 around the rotation axis 40 of the tool shaft 36 will cause vibrations, which will be transmitted to other parts of the power tool 10, including the tool housing 12. At least one threshold value can be defined for the vibration / acceleration. If the vibration / acceleration exceeds the threshold value, the power tool 10 is considered to be in the on state; if the vibration / acceleration is below the threshold value, the power tool 10 is considered to be in the off state. The sensed vibration / acceleration can be filtered and the operating state is determined based on the filtered value.

[0096] The determined operating state of the power tool can be used for many different tasks, including evaluating the proper function of the power tool 10 and / or the motor 24, installing the correct working element 38, the backing pad 48 and / or the polishing or grinding parts, etc. The light unit 100 can be configured to automatically drive the switching element 108 so as to switch the light unit 100 between the on state and the off state according to the sensed vibration amplitude. Therefore, the sensed vibration / acceleration and / or the determined operating state of the power tool 10 can be used to turn on or off at least one light source 104 of the light unit 100. The advantage of this is that the working area 102 is automatically illuminated when the power tool 10 is started and intended for use. Then, after the power tool 10 is turned off, the lighting of the working area 102 is also turned off. The activation and / or deactivation of the light source 104 can be achieved with a time delay after the vibration / acceleration exceeds or falls below a threshold value and / or a specific operating state of the power tool 10 is detected.

[0097] Finally, it is proposed that the lighting unit 100 comprises a radio communication device 140 (see Figure 6 ), which is configured to transmit a radio signal 142 representing the operating status of the power tool 10. The radio signal 142 can be received by an external or remote component, such as a dust suction device or vacuum cleaner (not shown) for sucking away dust-laden air from the grinding power tool 10. The radio signal 142 can be used to activate and deactivate the dust suction device or vacuum cleaner, and / or to increase or decrease the motor speed of the vacuum generating unit of the dust suction device or vacuum cleaner.

[0098] For example, after receiving the radio signal 142 indicating the start of the power tool 10 from the light unit 100, the dust suction device automatically turns on. The suction hose of the dust suction device can be connected to the suction port of the grinding power tool 10 so as to suck the dust-laden air in the working area 102 of the power tool 102. Similarly, when the power tool 10 is turned off again, the dust suction device receives the corresponding radio signal 142 and automatically turns off. The time of turning off the suction device is preferably delayed with the time of receiving the radio signal 142 indicating the power tool 10 is turned off. In addition or alternatively, the radio signal 142 indicating the power tool 10 is turned off can also be sent with a time delay related to the power tool 10 being turned off. The radio signal 142 and the data contained therein can adopt any communication standard known today or to be developed, including WiFi, BlueTooth, ZigBee or similar standards. The dust suction device or vacuum cleaner is equipped with a corresponding radio communication device, which is configured to receive the radio signal 142 from the radio communication device 140 of the light device 100.

[0099] The radio communication link between the radio communication device 140 of the lighting unit 100 and the corresponding radio communication device of the dust collecting device or vacuum cleaner is preferably strictly unidirectional, at least during the intended use and transmission of useful data. However, it is conceivable that during the setting and configuration of the radio communication link, the configuration data are transmitted bidirectionally via the radio communication link.

Claims

1. A handheld power tool (10) comprising a tool housing (12) and a motor (24) located therein, and a tool shaft (36), the tool shaft (36) having a rotation axis (40) which is driven by the motor (24) in operation so that the tool shaft (36) performs a rotational movement about its rotation axis (40), and further comprising a working element (38) connected to the distal end of the tool shaft (36) and performing a working movement about the rotation axis (40) of the tool shaft (36) during operation of the motor (24), and a light unit (100) releasably attached to the tool housing (12) so that a working area (102) where the working element (38) operates is illuminated during the intended use of the power tool (10), It is characterized in that The light emitting unit (100) comprises: at least one light source (104) for emitting light toward a working area (102) when the light emitting device (100) is mounted on the tool housing (12); a switch element (108) for switching the light-emitting unit (100) between an on state and an off state, wherein in the on state, the at least one light source (104) emits light, and in the off state, the at least one light source (104) does not emit light; An energy storage device (110) for storing electrical energy and supplying electrical energy to the at least one light source (104) when the light-emitting unit (100) is in an on state; an outer housing (112), the at least one light source (104) being located in the outer housing (112) in such a way that it emits light in a direction (106) toward a working area (102) when the light unit (100) is attached to the tool housing (12), a switch element (108) being located in the outer housing (112) in such a way that a user of the power tool (10) can operate it from outside the outer housing (112) when the light unit (100) is attached to the tool housing (12), and an energy storage device (110) being located in the outer housing (112), The light unit (100) is capable of operating as a self-sufficient unit after being separated and removed from the tool housing (12) so as to illuminate areas outside the working area (102) of the working element (38) during the intended use of the power tool (10), and / or to illuminate the working area (102) from other incident directions or angles that are different from the perspective of the user of the power tool (10).

2. The power tool (10) according to claim 1, characterized in that: The at least one light source (104) comprises a light emitting diode, and / or the energy storage device (110) comprises a battery, preferably a rechargeable battery.

3. The power tool (10) according to claim 1 or 2, characterized in that: The outer shell (112) of the light emitting unit (100) is made of plastic material, and / or the shape of the outer shell (112) of the light emitting unit (100) corresponds to a part of the tool housing (12), so that the light emitting unit (100) and the tool housing (12) can be releasably attached (116) by means of a form-fitting connection between the outer shell (112) of the light emitting unit (100) and the corresponding shape parts of the tool housing (12).

4. The power tool (10) according to claim 3, characterized in that: The shape of the outer shell (112) of the light emitting unit (100) corresponds to the front part (44) of the tool housing (12), and the releasable attachment (116) of the light emitting unit (100) to the tool housing (12) is achieved by a form-fitting connection between the outer shell (112) of the light emitting unit (100) and the front part (44) of the tool housing (12).

5. The power tool (10) according to one of the preceding claims, characterized in that When the light emitting unit (100) is connected to the tool housing (12), the contact surface of the outer shell (112) of the light emitting unit (100) is in full contact with the corresponding outer surface of the tool housing (12).

6. The power tool (10) according to claim 5, characterized in that: The contact surface has a three-dimensional extension.

7. The power tool (10) according to one of the preceding claims, characterized in that The releasable attachment (116) between the light unit (100) and the tool housing (12) is achieved by a snap connection (118, 120) between the outer housing (112) of the light unit (100) and the tool housing (12).

8. The power tool (10) according to one of the preceding claims, characterized in that Releasable attachment (116) of a light unit (100) to a tool housing (12) is achieved by means of interacting magnetic elements (122, 124) provided within or on an outer housing (112) of the light unit (100) and within or on the tool housing (12).

9. The power tool (10) according to claim 8, characterized in that: The magnetic element (122, 124) includes one or more permanent magnets (122, 124) and / or one or more ferromagnetic elements.

10. The power tool (10) according to one of the preceding claims, characterized in that The three-dimensional shape of the outer shell (112) of the light emitting unit (100) is adapted to the outer shape of a portion of the tool housing (12), and the light emitting unit (100) can be releasably attached to the portion of the tool housing (12). When the light emitting unit (100) is attached to the tool housing (12), the outer shell (112) of the light emitting unit (100) is flush with at least some adjacent surfaces of the tool housing (12).

11. The power tool (10) according to one of the preceding claims, characterized in that The light emitting unit (100) includes an acceleration sensor (138) which is configured to sense the vibration of the power tool (10) when the light emitting unit (100) is connected to the tool housing (12), and to determine the operating state of the power tool (10) based on the sensed vibration amplitude, and is preferably configured to automatically drive the switch element (108) based on the sensed vibration amplitude so as to switch the light emitting unit (100) between an on state and an off state.

12. The power tool (10) according to claim 11, characterized in that: The lighting unit (100) includes a radio communication device (140) configured to transmit a radio signal (142) representative of a determined operating state of the power tool (10).

13. A light emitting unit (100), comprising: at least one light source (104) for emitting light; a switch element (108) for switching the light-emitting unit (100) between an on state and an off state, wherein in the on state, the at least one light source (104) emits light, and in the off state, the at least one light source (104) does not emit light; An energy storage device (110) for storing electrical energy and supplying electrical energy to the at least one light source (104) when the light-emitting unit (100) is in an on state; An external housing (112), wherein the at least one light source (104) is located in the external housing (112) in a manner to emit light toward an area outside the external housing (112), the switch element (108) is located in the external housing (112) in a manner that a user can operate it from the outside of the external housing (112), and the energy storage device (110) is located in the external housing (112); wherein the lighting unit (100) is capable of operating as a self-sufficient unit; It is characterized in that The light unit (100) is configured to be releasably attached to a tool housing (12) of a power tool (10) according to one of the preceding claims; The at least one light source (104) is adapted to emit light in a direction (106) toward a working area (102) where a working element (38) of the power tool (10) operates when the light unit (100) is attached to the tool housing (12) during intended use of the power tool (10); The at least one light source (104) is located in the outer housing (112) in such a way that it emits light in a direction (106) toward the working area (102) when the light unit (100) is attached to the tool housing (12), and The switch element (108) is located in the outer housing in such a manner that it can be operated by a user of the power tool (10) from outside the outer housing (112) when the light unit (100) is attached to the tool housing (12); The light unit (100) is capable of operating as a self-sufficient unit after being separated and removed from the tool housing (12) so as to illuminate areas outside the working area (102) of the working element (38) during the intended use of the power tool (10), and / or to illuminate the working area (102) from other incident directions and / or angles that are different from the perspective of the user of the power tool (10).

14. The light emitting unit (100) according to claim 13, characterized in that: The three-dimensional shape of the outer shell (112) of the light emitting unit (100) is adapted to the outer shape of a portion of the tool housing (12), in particular the front portion (44) of the tool housing (12), and the light emitting unit (100) can be releasably attached to the portion of the tool housing (12). When the light emitting unit (100) is attached to the tool housing (12), the outer shell (112) of the light emitting unit (100) is flush with at least some adjacent surfaces of the tool housing (12).

15. The light emitting unit (100) according to claim 13 or 14, characterized in that: The light emitting unit (100) includes a magnetic element (122) or a snap-on connection component (118, 120) to achieve releasable attachment (116) of the light emitting unit (100) to the tool housing (12), and / or the light emitting unit (100) includes an acceleration sensor (138) configured to sense vibration of the power tool (10) when the light emitting unit (100) is connected to the tool housing (12) and determine the operating state of the power tool (10) based on the magnitude of the sensed vibration, and / or the light emitting unit (100) includes a radio communication device (140) configured to transmit a radio signal (142) representing the determined operating state of the power tool (10).

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