MACHINE TOOL, IN PARTICULAR CORDLESS DRILL OR CORDLESS SCREWDRIVER

Abstract

Handheld power tool having a housing with a machining axis along which a tool is or can be arranged, and having a lighting device that has at least one activatable lamp, the lighting device generating work light within a beam angle with an increased or maximum light intensity in a main emission direction in order to illuminate a work region, and having at least one light sensor for measuring the light intensity, characterized in that the light sensor detects the light intensity of the work light reflected on the work region during operation and generates control signals representing the light intensity, in that an adjustment unit is provided for setting and/or adjusting the work light generated by the lighting device, and in that a control unit is provided which controls the adjustment unit on the basis of the sensor signals during operation.

Claims

1. Handheld power tool comprising a housing comprising a machining axis along which a tool is or can be arranged, comprising a lighting device that has at least one activatable lamp, the lighting device generating work light within a beam angle with an increased or maximum light intensity in a main emission direction in order to illuminate a work region, and comprising at least one light sensor for measuring the light intensity, characterized in that the light sensor detects the light intensity of the work light reflected on the work region during operation and generates control signals representing the light intensity, in that an adjustment unit is provided for setting and/or adjusting the work light generated by the lighting device, and in that a control unit is provided which controls the adjustment unit on the basis of the sensor signals during operation.

2. Handheld power tool according to claim 1, characterized in that the adjustment unit and the lighting device are designed in such a way that the main emission direction, the beam shape and/or the beam angle can be set and/or adjusted by means of the adjustment unit.

3. Handheld power tool according to claim 1, characterized in that the adjustment unit and the lighting device are designed in such a way that the light intensity of the work light and/or the number of activated lamps can be set and/or adjusted by means of the adjustment unit.

4. Handheld power tool according to claim 1, characterized in that the control unit is designed such that it controls the adjustment unit during operation in such a way that the main emission direction is adjusted into the target region, in which the sensor axis of the light sensor and/or the machining axis intersects the work region.

5. Handheld power tool according to claim 1, characterized in that the control unit is designed such that it controls the adjustment unit during operation in such a way that the increased or maximum light intensity of the work light in the work region is constant or largely constant.

6. Handheld power tool according to claim 1, characterized in that the light sensor and/or at least one further light sensor detects the intensity of the ambient light and in that the control unit is designed such that it controls the adjustment unit on the basis of the ambient light during operation.

7. Handheld power tool according to claim 1, characterized in that the lighting device and/or the at least one lamp is arranged such that it can be pivoted at least about one pivot axis in order to adjust the main emission direction.

8. Handheld power tool according to claim 1, characterized in that optics are provided for influencing the work light.

9. Handheld power tool according to claim 1, characterized in that the at least one light sensor is arranged in or on the housing, and in that the sensor axis of the light sensor is located in or near the machining axis.

10. Handheld power tool according to claim 1, characterized in that a plurality of light sensors is arranged around the machining axis so that the machining axis lies in the detection regions thereof.

11. Handheld power tool according to claim 1, characterized in that the sensor axis of the at least one light sensor can be aligned manually with a target region in the work region.

12. Handheld power tool according to claim 1, characterized in that the lighting device is designed to project information onto the work region.

13. Handheld power tool according to, characterized in that the light sensor comprises at least one photodiode, a photoresistor and/or CCD sensors or is designed as a camera comprising CCD sensors.

14. Handheld power tool according to claim 1, characterized in that the housing has a handle portion and a base, the tool being provided on the side of the handle portion remote from the base, and the lighting device being arranged in or on the base.

15. Handheld power tool according to claim 14, characterized in that the handheld power tool is designed as a battery screwdriver or battery drill, it being possible to arrange the rechargeable battery in or on the base.

16. Method for operating a handheld power tool, in particular a handheld power tool according to claim 1, characterized in that the sensor axis of the light sensor is directed to a target region in the work area, and in that the lighting device illuminates the work region and is set or adjusted such that the main emission direction is directed to the target region.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In the drawings:

[0025] FIG. 1 shows a handheld power tool according to the invention in a first machining position;

[0026] FIG. 2 shows the handheld power tool according to FIG. 1 in a second work position;

[0027] FIG. 3 shows the handheld power tool according to FIG. 1 in a third work position; and

[0028] FIG. 4 schematically shows an enlarged section of the handheld power tool according to FIG. 1.

DETAILED DESCRIPTION

[0029] The handheld power tool 10 shown in FIGS. 1 to 3 in the form of a cordless battery screwdriver comprises a housing 12 with a tool holder 14 for receiving a tool along a machining axis 17, in this case for receiving a drill 16. Instead of the drill 16, other tools such as screw attachments, polishing attachments or the like can of course also be used. The tool holder 14 can be a plug-in holder, a drill chuck or any other tool holder.

[0030] The housing 12 has a handle portion 18 and a base 20 in which a rechargeable battery is housed. A motor (not shown) and a gear unit for driving the tool holder 14 or the drill 16 are provided within the housing 12. The motor can be controlled via a pressure switch 22.

[0031] As is clear from FIGS. 1 to 3, a lighting device 24 with lamps 26 is provided on the base 20, which can be seen in the section according to FIG. 4. The lighting device 24 with the lamps 26 is used to provide work light 28 within a work region 30. The work region 30 can be a largely flat surface such as the surface of a wall 32, for example.

[0032] In order to illuminate the work region 30, the lighting device 24 generates a light cone 34 which extends around a main emission direction 36. The light cone 34 encloses a beam angle 38. The work light 28 has an increased light intensity in the main emission direction 36, which should be made clear in FIGS. 1 to 3 by the maximum of the schematically indicated light distribution of the work light 28. In the view according to FIG. 1, the increased light intensity 40 is not in the region in which the tip of the drill 16 acts against the work region 30 (target region); rather, it is offset by the amount 42.

[0033] The handheld power tool 10 further comprises a light sensor 44 for measuring the light intensity in the work region 30. The light sensor 44 is preferably arranged such that its sensor axis 46 extends along the machining axis 17.

[0034] The light sensor 44 is also designed in such a way that it has a comparatively small detection region 48, extending along a sensor axis 46, for detecting the light intensity.

[0035] Even if only one light sensor 44 is provided in FIGS. 1 to 3, it is conceivable to arrange a plurality of light sensors, in particular around the machining axis 17 on the housing 12. The light sensors 44 are also used to detect the light intensity in the detection region 44.

[0036] During operation, the light sensor 44 is used, as already mentioned, to detect the work light 28 reflected on the work region 30. The light sensor 44 generates sensor signals which represent the light intensity and are fed to a control unit 50. The control unit 50 is used to control an adjustment unit 52, by means of which the lighting device 24 is controlled on the basis of the sensor signals generated by the light sensor 44. By means of the adjustment unit, the lighting unit 24 can be set or adjusted in such a way that the main emission direction 36, the beam angle 38, the light intensity of the work light 28 and/or the number of activatable lamps 26 can be set and/or adjusted.

[0037] The adjustment unit 52 can comprise a plurality of actuators. According to the schematic view in FIG. 4, the adjustment unit 52 comprises an adjustment drive 54 and adjustment optics 56, for example. By means of the adjusting drive 54, for example, the lighting device 24 can be pivoted about a pivot axis 58, the pivot axis 58 preferably being arranged so as to extend perpendicularly to the machining axis 17. By pivoting the lighting device 24, the main emission direction 36 can be adjusted with respect to the power tool 10 or with respect to the work region 30. According to the invention, it is also conceivable for the lighting device 24 to be arranged so as to be pivotable not only about one pivot axis 58, but rather about a plurality of pivot axes. For this purpose, it is conceivable that the lighting device 24 is mounted on a carrier 62 via a correspondingly suitable joint 60, for example a ball joint.

[0038] The adjustment optics 56 can in particular contain lenses, prisms and/or reflectors and can preferably be designed such that the beam angle 38 and the beam shape can be adjusted.

[0039] The adjustment unit 52 can also be designed such that the intensity of the work light 28 generated by the lamps 26 can be adjusted.

[0040] The control unit 50 is designed such that, during operation, it controls the adjustment unit 52 in particular such that the main emission direction 36 is adjusted into the detection area 48 surrounding the sensor axis 46 of the light sensor 44, as shown in FIG. 2. The distance 42 between the increased light intensity 40 of the work light 28 and the sensor axis 46, and thus the machining axis 17, is minimized and is preferably zero.

[0041] During operation of the handheld power tool 10, this can be achieved as follows. As shown in FIG. 1, the handheld power tool 10 is placed with the tip of the drill 16 onto the work region 30. The light sensor 44 is directed to the detection region 48, which represents a target region in which an increased light intensity is to be provided in the work region 30. In a next step, the lamp 26 illuminates the conceivable work region 30, for example by pivoting the lighting device 24 about the pivot axis 58 from one pivot end position to another pivot end position. The area of increased light intensity 40 is thus moved over the entire conceivable work region. While the work light 28 is moving over the entire work region 30, the light sensor 44 detects the light intensity in the detection region 48. During this calibration process, the setting of the lighting device 24, in which the light sensor 44 detects the maximum light intensity 40, can thus be determined. In this setting, there are thus optimal lighting conditions in the target region of the work region 30, i.e. in the region in which the main emission direction 36 is directed to the detection region 48, or in the region in which the main emission direction 36 intersects the sensor axis 46. As is clear from FIG. 2, the maximum light intensity 40 then lies in the machining axis 17 or in the sensor axis 46.

[0042] As a result, it can be ensured that the optimal light distribution, i.e. the region of increased light intensity 40, is adjusted into the target region in which the drill 16 acts against the work region 30. The adjustment takes place automatically without the involvement of the person guiding the handheld power tool 10.

[0043] During the machining process, the drill 12 penetrates into the work region 30 or into the wall 32, which is shown in FIG. 3. This changes the distance between the handheld power tool 10 and the work region 30. The control unit 50 is now designed such that it controls the adjustment unit 52 during the machining process in such a way that the work light 28, and in particular the main emission direction 38, remains in the detection region 48 in the work region. Consequently, the closer the handheld power tool 10 comes to the work region, the greater the angle 64 between the sensor axis 46 and the main emission direction 36. The light emitted by the lighting device 24 is consequently tracked so that optimal lighting conditions prevail in the detection region 48 or in the region in which the sensor axis 46 intersects the work region 30.

[0044] Due to the handheld power tool 10 approaching the work region 30 during the machining process, the light intensity of the work light 28 in the work region 30 also increases. The closer the lighting device 24 comes to the work region 30, the brighter the work light reflected there becomes. The dashed line 66 in FIG. 3 shows the increased light intensity which would result if the handheld power tool 10 is brought closer to the work region 30, without the light intensity of the light emitted by the lamps 26 being adjusted. In order to counteract this, the lamps 26 are controlled by the control unit 50 in such a way that the closer the handheld power tool 10 comes to the work region 30, the less the intensity of the emitted light. As a result, an overall constant light intensity is achieved during the entire machining process, as indicated in FIG. 3 with the solid line.

[0045] A further light sensor, which is used to detect the ambient light, can also be provided on the handheld power tool 10. Depending on the brightness of the ambient light, the control unit 50 can thus control the lamps 26 in such a way that optimal illumination can be provided on the basis of the ambient light. In this way, glare affecting the person operating the handheld power tool can be avoided in particular.

[0046] The light sensor 44 is arranged so as to be adjustable. The sensor axis of the light sensor 44 or the detection area 48 of the light sensor 44 can thus be moved to another point in the work region 30. This has the consequence that this target region, or the detection region 48 of the light sensor, is optimally illuminated during machining, since the main emission direction 36 is then aligned with this target region during the machining process.

[0047] The lighting device 24 can also be designed as a digital projector in order to display information on the work region 30. The information can be a safety notice or operating instructions for the handheld power tool, for example. It is also conceivable to display the machine states, the charge state of the rechargeable battery, the machine temperature and the like.

[0048] The at least one light sensor can be designed, for example, as a photodiode, photoresistor or as CCD sensors.