Abstract:
An accessory is provided that can be connected to a power drill or can be fastened at the power drill in a detachable fashion. The accessory may comprise detachable or fixed means for fastening at the power drill, e.g., clips, sleeves, clamps, screws. A measuring device is provided to determine measurements, including an incline of the power drill in reference to an operating surface and/or a distance of the power drill from the operating surface. A projector is provided to project the symbols according to the measurements determined to the operating surface.

Description:
RELATED APPLICATIONS 
       [0001]    The present application claims priority to German Patent Application DE 10 2010 064 118.9 filed Dec. 23, 2010 and entitled “Hilfseinrichtung einer Bohrmaschine and Steuerungsverfahren” (“Accessory for a Power Drill and Control Method”), the entire content of which is incorporated herein by reference. 
       FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    [Not Applicable] 
       MICROFICHE/COPYRIGHT REFERENCE 
       [0003]    [Not Applicable] 
       BACKGROUND OF THE INVENTION 
       [0004]    The present invention relates to an accessory for a power drill to indicate the measurements of the power drill. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    An accessory according to aspects of the present invention is connected to a power drill or can be fastened at a power drill in a detachable fashion. The accessory may be provided with detachable or permanent means for fastening at the power drill, e.g., clips, sleeves, clamps, screws. A measuring device is provided in order to determine measurements regarding the incline of the power drill in reference to an operating surface and/or a distance of the power drill from the operating surface. A projector is provided to appropriately project symbols of the measurements detected to the operating surface. One embodiment provides that the projector is arranged radiating in an operating direction of the power drill. 
         [0006]    A control method according to aspects of the invention for an accessory has the following steps: determining measurements of the power drill via a measuring device and projecting via a projector the measurements to a surface processed by the power drill. The operating surface becomes the display surface. The user can keep focusing on the operating surface and is not forced to look to a display arranged at the power drill. This way, a safe and pleasant operation is achieved. 
         [0007]    One embodiment provides that the projector comprises a display optic and an illuminated monitor with several electro-optic illuminants, which can be addressed individually. In this embodiment, the display of the monitor itself cannot be viewed by the user, however the image projected by the display optic can be seen. The monitor comprises a sufficient number of symbols or pixels, which can be individually addressed and can display different measurements. A first group of illuminants is switched lucent for first measurements and a second group of illuminants is switched lucent for second measurements, with the first group differing from the second group by at least one illuminant when the first measurements and the second measurements are different. 
         [0008]    One embodiment comprises a laser source, an intensity modulator, and a pivotal minor animated by an inciter, which deflects the laser beam in the direction towards the operating surface. The intensity modulator can be controlled according to the symbol to be displayed. The light beam is deflected by the moving mirror over the operating surface. The intensity modulator switches off the light beam when it would reach sections outside a symbol to be displayed, and switches the light beam back on as soon as it reaches an area inside the symbol to be displayed. 
         [0009]    One embodiment provides the following steps: projecting with the projector a first light spot and a second light spot; recording the first light spot and the second light spot in an image via a camera; determining a virtual first distance of the first light spot, recorded in the image, from a reference point; determining a virtual second distance of the second light spot, recorded in the image, from the reference point; determining the incline of the power drill in reference to the operating surface based on the first distance and the second distance; and displaying the incline via the projector. The projector already used for displaying measurements can also be used as a part of a measuring device. Being another part, the camera records the pattern projected by the projector onto the operating surface and the processing device determines therefrom an incline and/or distance. 
         [0010]    One embodiment provides that a first light beam is emitted in a first direction for creating the first light spot, a second light beam in a second direction for creating the second light spot, and a third light beam in a third direction for creating a third light spot, with an azimuth angle of the first light beam in reference to the optic axis of the camera and an azimuth angle of the second light beam in reference to the optic axis of the camera being different, and an amplitude of the first light beam in reference to the optic axis and an amplitude of the third light beam in reference to the optic axis being different. The three light beams allow conclusions concerning the incline and distance in absolute values. The determined values can be displayed to the user, for example, in the form of numbers. 
     
    
     
       BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
         [0011]    The following description explains the invention based on exemplary embodiments and figures. 
           [0012]      FIG. 1  illustrates a power drill with an accessory formed in accordance with an embodiment of the present invention. 
           [0013]      FIG. 2  illustrates an image recorded by an accessory formed in accordance with an embodiment of the present invention. 
           [0014]      FIG. 3  illustrates a detailed view of an optic measuring device of an accessory formed in accordance with an embodiment of the present invention. 
           [0015]      FIG. 4  illustrates a detailed view of an optic measuring device of an accessory formed in accordance with an embodiment of the present invention. 
           [0016]      FIG. 5  illustrates a monitor of a display device of an accessory formed in accordance with an embodiment of the present invention. 
           [0017]      FIG. 6  illustrates a projector of a display device of an accessory formed in accordance with an embodiment of the present invention. 
           [0018]      FIG. 7  illustrates a projector of a display device of an accessory formed in accordance with an embodiment of the present invention. 
       
    
    
       [0019]    In the figures, identical or functionally identical elements are identified by the same reference character, unless stipulated otherwise. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0020]      FIG. 1  shows an exemplary power drill  1 , formed in accordance with an embodiment of the present invention, which can rotationally drive a drill bit  2  about an operating axis  3 . The user presses the drill bit  2  in the operating direction  4  to an operating surface  5  of a work piece  6  to be processed. Here, the rotating drill bit  2  creates a bore hole  7  in the work piece  6 . The drill bit  2  comprises a cutting element made from hard metal, e.g., sintered tungsten carbide and/or diamond, which removes material from the work piece  6  by rotating about the axis. The shavings can be removed via the helical shaft or a hollow shaft of the drill. The cutting elements may also be arranged along a circular face of a cup-shaped drill. 
         [0021]    The drive may comprise a motor  8 , e.g., an electric motor, a transmission  9 , and a drive screw  10 . The drive screw  10  transfers the torque to a tool accept  11 , into which a drill bit  2  can be inserted. The user can hold and/or guide the power drill  1  via a handle  12 , which is arranged preferably at an end of the machine housing  13  distanced from the tool accept  11 . 
         [0022]    An accessory  20  renders it easier for the user to align the operating axis  3  of the power drill  1  to a desired angle, preferably perpendicularly, in reference to the processed operating surface  5  and to guide it in the aligned form. An optic measurement device  21  can detect the orientation of its optic axis  22  in reference to the work piece  6 . A display device  23  shows the present orientation to the user. Additionally, the accessory  20  can determine a present drilling depth and visualize it via the display device  23 . 
         [0023]    The optic measuring device  21  of the accessory  20  comprises a projector  24  and a camera  25 , which are shown in detail in  FIG. 3 . The projector  24  creates at least one first light spot  26  on the operating surface  5  and a second light spot  27 . The camera  25  is preferably arranged on the optic axis  22  and records the operating surface  5  and the light spots  26 ,  27  created thereon in an image  28  ( FIG. 2 ). Based on the image  28  and the light spots  26 ,  27  recorded, a processing device  29  determines an orientation of the optic axis  22  in reference to the operating surface  5 . 
         [0024]    An example of a projector  24  includes two laser light sources  30 , e.g., laser diodes, which create a first light beam  31  and a second light beam  32 . The first light beam  31  is emitted in a first direction and the second light beam  32  in a second direction, which is different from the first direction. 
         [0025]    The direction of the light beams  31 ,  32  is stated in the following in the form of angular coordinates in reference to the optic axis  22 . The amplitude describes the incline of the light beam in reference to the optic axis  22  in a level, which is stretched between the light beam and the optic axis  22 . An azimuth angle represents the orientation of the light beam in a rotational direction about the optical axis  22  and can be determined in a projection to a level perpendicular in reference to the optic axis  22  (cf.  FIG. 2 ). 
         [0026]    Preferably, a first azimuth angle  33  of the first light beam  31  differs from a second azimuth angle  34  of the second light beam  32 . The first azimuth angle  33  may differ by 180 degrees from the second azimuth angle  34 , i.e. the two light beams  31 ,  32  are located in a level with the optic axis  22 . A first amplitude  35  of the first light beam  31  and a second amplitude  36  of the second light beam  32  may be identical. The amplitudes  35 ,  36  are preferably at a range from about 10 degrees to about 60 degrees. The projector  24  can emit light beams  31 ,  32  intersecting the optic axis  22 . 
         [0027]    The first light beam  31  leads to the first light spot  26  on the operating surface  5  and the second light beam  32  to the second light spot  27 . The relative orientation of the optic axis  22  in reference to the work piece  6  can be determined from the relative position of the first and the second light spot in reference to the optic axis  22  and the distances. The light beams  31 ,  32  emitted by the projector  24  may show a circular cross section or a different shape. Light spots of small diameters are preferred due to their easily determined position, however differently shaped light spots (e.g., non-circular shapes, arrows, crosses) may be projected to the work piece  6  as well. 
         [0028]    The camera  25  records the operating surface  5  with the light spots  26 ,  27  on the work piece  6 . The camera  25  may include a display optic  37 , which displays the operating surface  5  on a spatially resolving photo sensor  38 . The photo sensor  38  converts the incoming light into an image  28 , which, spatially resolved in an image level  39 , displays an intensity of light. The light spots  26 ,  27  are beneficially of such brightness that they show the highest intensity displayed in the image  28 . A color filter  40  adjusted to the color of the light spots  26 ,  27  may be arranged to amplify the contrast in front of the photo sensor  38 . 
         [0029]    The display optic  37  may comprise an objective  41  comprising one or more lenses  42 . The lenses  42  are preferably arranged centrally and perpendicularly in reference to the optic axis  22 . Instead or in addition to the objective  41  an aperture may also be provided. The projector  24  and the camera  25  are arranged distanced from each other such that the first light spot  26  is detected by the camera  25  at a direction different from the first direction and the second light spot  27  at a direction different from the second direction. 
         [0030]    A processing device  29  reads the image  28  from the camera  25 , particularly the spatially resolving photo sensor  38 . The brightest spots of the image are interpreted as the virtually displayed light spots  26 ,  27 . The position of the displayed light spots  26 ,  27  in reference to a reference point  43  in the image  28  or in the image level  39  is determined by the processing device  29 . In the image  28  a first distance  44  of the first light spot  26  is measured from the reference point  43 , and a second distance  45  of the second light spot  26  from the reference point  43  is also measured. The distances measured are virtual. The measuring may include a determination of the coordinates of the light spots  26 ,  27  in the image. In order to determine the distances  44 ,  45 , distances allocated to the coordinates are stored in the reference table in a storage element  46 , e.g., RAM, flash-RAM of the processing device  29 . The reference point  43  may be set arbitrarily. Preferably, the reference point  43  represents the interface of the image level  39  with the optic axis  22  or the center of the image  28 . 
         [0031]    An operating mode of the accessory  20  supports the user in the perpendicular alignment of the power drill  1  in reference to the work piece  6 . The accessory  20  is fastened at the power drill  1  such that the optic axis  22  is parallel to the operating axis  3 . The processing device  29  transmits a control signal, which indicates that the optic axis  22  in reference to the work piece  6  is at an incline when the first distance  44  is different from the second distance  45 . The control signal indicates in which direction the distances  44 ,  45  are greater. The display device  23  visualizes the control signal to the user. For example, the display device  23  shows an arrow indicating the direction. The user will pivot the handle  12  in the direction about the bore hole based on the indication until the distances  44 ,  45  are of equal size and the optic axis  22  is perpendicular in reference to the work piece  6 . 
         [0032]    The optic measuring device  21  may be arranged at a platform  47  pivotal in reference to the operating axis  3 . In particular, an amplitude may be adjusted between the optic axis  22  and the operating axis  3 . The platform may for example be fastened via a ball joint  48  or pivotal joints at the housing of the power drill  1 . A user adjusts a desired, e.g., not parallel, orientation of the optic axis  22  in reference to the operating axis  3 . The processing device  29  and the display device  23  indicate to the user to guide the power drill  1  with the optical axis  22  perpendicularly in reference to the work piece  6 . A drilled bore hole then has an incline in reference to the operating surface  5 , which is equivalent to the adjusted orientation of the operating axis  3  in reference to the optic axis  22 . 
         [0033]    In another operating mode the accessory  20  can determine the absolute angle of the optic axis  22  in reference to the operating surface  5 . The projector  24  creates a third light beam  49 , which is preferably parallel in reference to the optic axis  22  and off-set in reference to the optic axis  22 . Instead of being parallel, the third light beam  49  may also show a slight amplitude, compared to the first light beam  31 , in reference to the optic axis  22 , e.g., ranging from about 0 degrees to about 5 degrees. A resulting third light spot  50  is detected by the camera  25 . A virtual third distance  51  of the displayed light spot  50  from the reference point  43  in the image  28  is determined. Based on the third distance  51  the distance  52  of the camera  25  from the work piece  6  is determined. The third distance  51  increases in the image  28  with the distance  52  reducing. Based on the distance  52 , the first distance  44 , and the second distance  45  and the amplitude  35  of the first light beam  31  and the amplitude  36  of the second light beam  32  the incline  53  of the optic axis  22  can be absolutely and quantifiably determined in reference to the operating surface  5 . Preferably, amplitudes  35  are stored in the storage element  46  equivalent to first, and second distances allocated to various distances  52 . The display device  23  preferably displays the absolute angle in the form of a number. 
         [0034]    Another embodiment provides that the first light beam  31  and the second light beam  32  show a different amplitude  35 ,  36  from the optic axis  22 . The two light beams  31 ,  32  may extend in a level, which for example includes the optic axis  22 . Preferably the first light beam  31  is parallel to the optic axis  22 , and the second light beam inclined in reference to the optic axis  22 . Using the optic axis  22  as the reference point  43 , the absolute incline  53  of the optic axis  22  in reference to the operating surface  5  can be directly determined from the first distance  44  and the second distance  45 . 
         [0035]    The photo sensor  38  may comprise a plurality of photosensitive cells, which are arranged on a grid. Coordinates of a light spot represent the cell and perhaps the column of the cell respectively illuminated by the light spot  26 ,  27 . One cell may be determined as the reference point  43 . The photo sensor  38  may include for example a CCD chip or an APS sensor. 
         [0036]    The camera  25  may record the bore hole  7  in the operating surface  5  and the drill bit  2  in the image  28 . The processing device  29  includes an image detection  54 , which identifies the bore hole  7  and determines its coordinates in the image  28 . The image detection  54  may, for example, first identify the drill bit  2 , e.g., using its oblong shape and/or based on a known orientation of the drill bit  2  in the image  28 , which due to a fixed or known arrangement of the camera  25  results in reference to the drill bit  2 . The coordinates of one end  55  of the visible part of the drill bit  2  are equivalent to the coordinates of the bore hole  7 . In the image  28  a distance  56  of the bore hole  7  from the reference point  43  is determined. The distance  56  is a measure for the distance  52  of the camera  25  from the bore hole  7  and thus the operating surface  5 . The processing device  29  can determine a distance of the power drill  1  based on the measurement and transmit it to the display device  23  for visualization. The distance  52  may also be used to determine the absolute angle  53 . 
         [0037]    The above-described embodiments can determine an incline deviating from the perpendicular or an absolute angle  53  of the optic axis  22  in reference to the work piece  6  in a first level. A further development provides additional light beams, which show azimuth angles differing by 90 degrees from the first and the second light beam  31 ,  32 . The processing of the light spots  57  of the other light beams may occur similar to the one of the first and second light beam  31 ,  32 . This way, the incline of a second level is determined in reference to the first perpendicular level. In order to determine the absolute angle  53 , additionally the third light beam  49  may be used, which shows a different amplitude to the other light beams  31 ,  32  in reference to the optic axis  22 . In one embodiment three light beams show different orientations, with two of them differing at least in their azimuth angles, and two at least in the amplitude. In addition to or instead of the third light beam  49  the measuring of the distance  56  of the bore hole  7  from the optic axis  22  can be used in the image  28  to determine the distance. 
         [0038]    The projector  24  may be composed from several individual, independent laser sources  30 . The laser diodes  30  may be arranged in a housing  58  according to the predetermined directions of the laser beams. The projector  24  may also comprise a beam splitter  59 , in order to split a light beam into two light beams  31 ,  49 . The beam splitter  59  may for example comprise a glass plate or a bundle of fiberglass. 
         [0039]    In one embodiment the projector  24  alternatively or additionally comprises an illuminating monitor  60  and a display optic  61  ( FIG. 4 ). The monitor  60  may represent, for example, a background-lit liquid crystal display, a matrix of light diodes, etc. The monitor  60  can display symbols composed from several light spots  62 . The display optic  61  displays the image shown on the monitor  60  on the operating surface  5 . The display optic  61  may include one or more lenses arranged along an optic axis  63  of the display optic  61 . The optic axis  63  extends through the monitor  60 , preferably through the center of the monitor  60 . Image spots near the optic axis  63  lead to largely parallel light beams in reference to the optic axis  22 , while image spots near the monitor edge are projected to the operating surface  5  by light beams  31 ,  32  inclined in reference to the optic axis  63 . The incline of the light beams can be adjusted by the focal length of the display optic  61 . 
         [0040]    The display device  23  comprises a monitor  64  fastened to a carrier  65  of the accessory  20 . The monitor  64  faces the user with its readable area  66 , i.e. oriented against the operating direction  4 . The user can read the information on the monitor  64  when guiding the power drill  1  in the operating direction  4 . Several electro-optic segments  67  can be switched independently of each other between the light and the dark status ( FIG. 5 ). The segments  67  may be illuminating, e.g., a cell or a matrix of light diodes, or covering a background illumination, e.g., several liquid crystal cells. The segments  67  may be embodied in the form of arrows, which are arranged rotated in 90-degree steps. In an incline of the optic axis  22  in reference to the operating surface  5  one of the segments  67  each is activated according to the control signal of the processing device  29 . The segments  67  may also be embodied as a plurality of image spots on a grid, which activated together show arrows, numbers, letters, etc. The example of  FIG. 5  shows a group of segments  67  switched dark, which indicate an incline to the right and thus prompt the user to pivot the power drill  1  to the left. The segments  67  are arranged on a surface of the accessory  20  facing away from the tool  2 . The user can directly read the directions shown on the accessory  20 . 
         [0041]    For example, the display device  22  comprises a projector  68 , which projects information to be displayed by the display device  22  to the operating surface  5  ( FIG. 6 ). The projector  68  points in the operating direction  4 . The projector  68  may also show a self-illuminating monitor  69  and a display optic  70 . 
         [0042]    The monitor  69  is composed of several individually addressed, electro-optic light elements  71 . Each of the electro-optic elements  71  can emit light in a switched state and in another switched state can emit no light. The electro-optic elements  71  may for example comprise background-illuminated liquid crystal displays, punctual or other geometrically designed light diodes, a field of micro-reflectors illuminated by a lamp, etc. As an example, the monitor  69  is shown with several electro-optic elements  71 , which are arranged on a grid. The image spots may be lit individually or in groups in order to display one or more desired symbols. The symbols are arrows, numbers, letters, etc. The measuring device  21  controls the projector  68 . Here, depending on data transmitted by the measurement device  21 , different groups of electro-optic elements  71  are switched lucent. The groups differ in pairs at least in one element  71 , which is switched for one group illuminating and the other group non-illuminating. 
         [0043]    The display optic  70  displays the symbols shown on the monitor  69  on the operating surface  5 . The display optic  70  comprises an objective  72  made from one or more lenses. The focal length and a focal point of the objective  72  may be adjustable. For example, the objective  72  may be mobile along its optical axis  73  by a sled  74 . Alternatively, the objective  72  may comprise a liquid lens, with its focal length being adjustable by applying an electric field. 
         [0044]    Another embodiment of the projector  68  has a light source  75  to create a light beam  76 , preferably a laser, and a deflection device  77  ( FIG. 7 ). The deflection device  77  has a minor  78 , for example, which is suspended rotationally or pivotally about two axes  79 . The mirror  78  may also be animated by an exciter  80 , e.g., piezo-electrically, magnetically, or electrostatically, to pivot about the two axes  79 . The mirror  78  may also be rotational about one or both axes  79 . Two pivotal or rotating minors may also be provided for the defection of the light beam  76  in two directions. The light beam  76  is deflected along a grid, e.g., of a Lissajous-figure over the operating surface  5 . 
         [0045]    A control device  81  switches an intensity of the light beam  76  depending on the position of the deflection device  77  in order to project symbols to the operating surface  5 . A switching pattern may be stored in a storage component of the control device  81  for various symbols required, e.g., arrows, numbers. The switching patterns determine the intensity in reference to the angular position of the minor  78 . The intensity of the light beam  76  is reduced as soon as the light beam  76  is outside the areas of the symbols. The switching of the intensity may occur by switching a power supply for the light source  75  via the control device  81 . Furthermore, the switching can occur by an intensity modulator  82 , which comprises e.g., a combination of a Pockels cell  83  to change polarization and a subsequent polarization filter  84  and/or a combination of an acoustic-optic modulator  85  to change the direction of distribution of the light beam and a subsequent blind  86 . 
         [0046]    One embodiment provides to also use the projector  68  of the display device  23  for the display of measurements for the generation of light spots  26 ,  27  on the operating surface  5  to measure via the measuring device  21 . An additional projector  24  of the measuring device  21  can be omitted. 
         [0047]    The accessory  20  may comprise a tensile tape  90 , which can be wrapped around a neck  91  or a handle of the power drill  1 . The tensile mechanism  91  clamps the tensile tape to the power drill  1 . Instead of a tensile tape, clips may also be clamped to the power drill  1  by the tensile mechanism  91 .