Abstract:
A positioning aid is disclosed for a core drilling machine, having a core drill for creating a hollow-cylindrical drill hole. The positioning aid includes a light source for creating a centring pattern on a workpiece. The positioning aid is fastened in a releasable and centred manner to the core drilling machine. The positioning aid may include a laser pointer, which is releasably fastened to a centring pin.

Description:
CROSSREFERENCES TO RELATED APPLICATIONS 
       [0001]    This claims priority from German patent application 102014117587.5, filed on Dec. 1, 2014. The entire content of this priority application is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The invention relates to a positioning aid for a core drilling machine. 
         [0003]    By a core drilling machine is understood, within the scope of this application, a drilling machine which in core drilling operation drills out only a hollow cylinder, whilst within the hollow cylinder the material is not cut, so that a core remains. Once the workpiece is fully drilled through, this core can be ejected or must be separated off in some other way. As a rule, core drilling machines are transportable. They are placed on the workpiece and fastened on the workpiece by means of a magnet in the drill stand or other suitable means (for example vacuum suction plate, fastening screws, etc.). Magnetic core drilling machines are also used for drilling with cylindrical solid drill bits, for counter-sinking and for reaming. 
       RELATED PRIOR ART 
       [0004]    In order to position a core drilling machine on the position to be drilled, centring pins are commonly used. The respective centring pin can be releasably inserted into the chuck of the core drilling machine. In order now to arrive at an accurate drilling position, on the one hand the drill must be displaced on the surface of the workpiece, while on the other hand the height of the centring pin must be altered with the cross feed in order that, during the displacement along the material surface, it does not touch this. As a result, several positioning operations are generally necessary to position the core drill exactly over the drilling site. This is a complex process. 
         [0005]    From US 2007/0068020 A1 a positioning aid for a drilling machine is known which includes a light source which is configured for releasable attachment to a drill chuck of the drilling machine. 
       SUMMARY OF THE INVENTION 
       [0006]    In view of this it is an object of the invention is to disclose an improved positioning aid for a core drilling machine. 
         [0007]    It is a further object of the invention to disclose a positioning aid for a core drilling machine that allows for a highly precise positioning of the core drilling machine. 
         [0008]    It is a further object of the invention to disclose a core drilling machine comprising a positioning aid allowing for an easy handling when positioning the core drilling machine. 
         [0009]    It is a further object of the invention to disclose a core drilling machine comprising a positioning aid allowing for an improved positioning of the core drilling machine on a workpiece. 
         [0010]    According to one aspect of the invention a positioning aid for a core drilling machine with a core drill is disclosed for creating a hollow-cylindrical drill hole, comprising a light source for creating a centring pattern on a workpiece, said light source being configured for releasable, centred fastening to said core drill. 
         [0011]    Through the use of a light source for creating a centring pattern on the workpiece, an accurate positioning is enabled without the need to alter for this purpose the distance of the drill chuck relative to the workpiece. The centring operation is made considerably easier. 
         [0012]    According to a further aspect of the invention, the light source comprises a laser pointer for creating the centring pattern. 
         [0013]    Since laser pointers are available at reasonable cost in great variety and in all possible versions, a highly precise, cost-effective centring option is herewith created. 
         [0014]    According to a further aspect of the invention, the positioning aid is configured for fastening to a centring pin. 
         [0015]    In this way, the centred receiving fixture of the centring pin, which receiving fixture is in any case provided on the core drill, is used to centre the positioning aid. 
         [0016]    The positioning aid can here be permanently connected to the centring pin, so that the latter is directly insertable by the end of the centring pin into the core drill. 
         [0017]    Alternatively, a releasable fastening of the positioning aid to the centring pin can also be provided. 
         [0018]    Since commercially available centring pins generally have a standard diameter amounting, for example, to 6.35 mm, a commercially available laser pointer, which is releasably mountable onto the centring pin, can equally be used as the centring aid. Further common dimensions for centring pins are 11.11 mm ( 7/16 inch diameter) and 8.0 mm. For these too, there are commercially available laser pointers. 
         [0019]    According to a further aspect of the invention, the positioning aid is configured to be automatically switched on when mounted onto the centring pin. 
         [0020]    A simplified handling is hereby obtained. 
         [0021]    According to a further aspect of the invention, the positioning aid has at one end a receiving fixture for fastening to a clamping chuck of the core drill. 
         [0022]    The positioning aid can thus be clamped directly into the clamping chuck of the core drill, whereby increased precision is achieved. A certain drawback lies in the fact that the complexity is somewhat increased, since, after the correct positioning, the positioning aid must first be unclamped again, after which the tool must be clamped in place. 
         [0023]    In a further aspect of the invention, the positioning aid has a light field for the lighting of a working area and a centring pattern for the centring. 
         [0024]    The ease of use is hereby further increased. 
         [0025]    Preferably the centring pattern here has a brighter illumination than the light field for the lighting. Thus the light field can firstly be used to acquire a rough positioning even under adverse lighting conditions, after which, once the work site is in the region of the light field, the centring pattern can be used for the exact positioning. 
         [0026]    Preferably, the positioning aid has its own power source, for instance in the form of a battery or an accumulator. 
         [0027]    As a result, a facilitated handling is obtained. 
         [0028]    According to a further embodiment of the invention, the positioning aid has a fastening device, for instance in the form of a magnet, for securement to the core drilling machine when in use. 
         [0029]    In this way, the positioning aid can be stowed on the core drilling machine as long as this is not being used. The positioning aid is thus ready to hand at all times whenever it is required. 
         [0030]    According to a further embodiment of the invention, the positioning aid has a switching device for switching the light source on and off, preferably for separate switching of the centring pattern and of a light field. 
         [0031]    In this way, the light source of the positioning aid can be switched on specifically when it is needed. Insofar as an additional (less strongly illuminated) light field is provided to light the work site, a separate circuit can if necessary be provided for this purpose. 
         [0032]    According to a further embodiment of the invention, the centring pattern comprises at least one laser point, a reticle or a circle. Of course, a combination of these patterns can also be provided, or other patterns which appear suitable for the positioning can also be used. 
         [0033]    In a core drilling machine comprising a positioning aid according to the invention, the positioning aid is releasably fastened, so that it can be removed prior to the start of the drilling operation. 
         [0034]    Preferably the core drill has a mounting for receiving the positioning aid when this is not in use. 
         [0035]    This mounting can here be in the form of a pocket, a magnet, a clampable mounting or similar, whereby a secure, easily releasable fastening is ensured during non-usage. 
         [0036]    Obviously the features of the invention which have been stated above, and those which are yet to be described below, can be used not only in the respectively defined combination, but also in other combinations or in isolation, without departing from the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]    Further features and advantages of the invention emerge from the following description of preferred illustrative embodiments with reference to the drawing, wherein: 
           [0038]      FIG. 1  shows a side view of a core drilling machine according to the invention with positioning aid; 
           [0039]      FIG. 2  shows an enlarged partial view of the core drilling machine in the region of the drill chuck with inserted core drill and additionally inserted positioning aid, which is represented partially in section; 
           [0040]      FIG. 3  shows a slightly modified embodiment of a positioning aid having at one end a receiving fixture which corresponds to the respective receiving fixture of a drill bit and thus allows a fastening in exchange for a drill bit; 
           [0041]      FIG. 4  shows a top view of a lighting pattern when the light source is switched on. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0042]      FIG. 1  shows a core drilling machine  10  according to the invention comprising a positioning aid  24 . 
         [0043]    The core drilling machine  10  which is known fundamentally in the prior art has a stand  12  comprising a magnetic foot  14  for releasable fastening on a ferromagnetic workpiece  26 . Provided on the stand  12  is a guide  16 , along which runs a slide  17  on which a drilling unit  18  is held. 
         [0044]    By actuation of a rotary cross feed  19 , the drilling unit  18  can be manually repositioned along the guide  16  in the direction of the workpiece  26  in the course of the drilling, or an automatic feed can be used. 
         [0045]    On the drilling unit  18  is provided a drill chuck  20 , in which a drilling tool  22  for the core drilling machine can be clamped by means of a rapid-action fastening. For the release, i.e. for the removal of the drilling tool  22 , the particular actuating ring of the drill chuck  20 , in the representation according to  FIG. 1 , has merely to be pulled downwards, whereby the drilling tool  22  is freed and can be pulled out. 
         [0046]    In addition, a positioning aid  24  for creating a light pattern can be fitted centrally into the drill chuck  20 . 
         [0047]    As can be seen in greater detail from  FIG. 2 , the positioning aid, denoted in its entirety by  24 , has a commercially available centring pin  30 , which is insertable by its end releasably into the drill chuck  20  in a known manner. Onto the outer end of the centring pin  30  is mounted a light source  25  in the form of a laser pointer. The light source  25  is configured to create a centring pattern on the workpiece  26 , as is indicated by the dotted line  34  in  FIG. 2 . 
         [0048]    The centring pattern  34  created on the surface of the workpiece  26  is represented by way of example in  FIG. 4  in top view. The centring pattern  34  can have a central laser point  52 , a reticle  48  and/or one or more circles  50 , in order to allow easy centring. 
         [0049]    In addition, for the illumination of the work site, a light field  36  can be provided, which light field, in the positioning and centring, facilitates an accurate orientation, for instance in dark surroundings. The light field  36 , which extends over a considerable area, preferably has a lower brightness than the centring pattern  34 , which is formed significantly brighter. 
         [0050]    Thus the core drilling machine  10 , for centring with the support of the light field  36 , can be displaced even in dark surroundings to the point where, if the centring pattern  34  is utilized, an exact positioning on the workpiece  26  is achieved. 
         [0051]    Following the positioning of the core drilling machine  10 , the positioning aid  24  is pulled off the centring pin  30 , so that the drilling operation can be commenced. The centring pin  30  remains in the drill chuck  20  during the core drilling and serves as an ejector for the core created in the core hole drilling. 
         [0052]      FIG. 3  shows a modification of the positioning aid, which is denoted in its entirety by  24   a.    
         [0053]    A centring pin has here been dispensed with. Instead, the positioning aid  24   a  has at its machine end a receiving fixture  32 , which corresponds to the drill bit holder of a drilling tool  22 . 
         [0054]    The positioning aid  24   a  can thus be inserted, in exchange for a drilling tool  22 , into the drill chuck  20 . 
         [0055]    As a result, an increased precision in the centring of the positioning aid  24   a  on the core drilling machine  10  is obtained. 
         [0056]    A certain drawback consists in the fact that the positioning aid cannot easily be pulled off the centring pin, but rather must be exchanged for the drilling tool  22 . 
         [0057]    In  FIG. 2 , on one side of the positioning aid  24  is further indicated a mounting  38 , which serves to secure it to the core drilling machine  10  when it is not in use. The mounting can here be constituted, for example, merely by a plane surface made of a ferromagnetic material, which surface cooperates with an associated magnet on the core drilling machine  10 . 
         [0058]    In  FIG. 1 , such a magnet is denoted by way of example by  28 . 
         [0059]    Obviously, any other fastening types for securement to the core drilling machine  10  during non-usage are of course possible. Thus the magnet could also, for example, be configured on the mounting  38  of the positioning aid  24 , or a pocket or some other suitable mounting, for instance with clip fastening, could, for example, be provided on the core drilling machine  10 . 
         [0060]    On the other side of the positioning aid  24   a,  opposite to the mounting  38 , a switching device is denoted by  40 , which switching device can be configured with one or two switches  42 ,  44 , for instance in order to allow a joint switching of light field  36  and centring pattern  34 , or a separate switching of light field  36  and centring pattern  34 . 
         [0061]    Furthermore, a battery, which can be constituted, for example, by a button cell, is denoted in dashed representation by  46 . 
         [0062]    At the lower end of the positioning aid  24   a,  the centring pattern in the form of a laser beam is denoted by  34 , and the outer periphery of the light field  36 , which serves to light the work site in adverse light conditions, is denoted by the two laterally dashed lines. 
         [0063]    With the aid of the light field  36 , the core drilling machine, during the positioning operation, can initially be positioned roughly in the region of the work site and then be precisely oriented with the aid of the centring pattern. 
         [0064]    Following the positioning and definitive securement of the core drilling machine  10 , the positioning aid  24   a  is pulled out by release of the drill chuck  20  and the drilling tool  22  subsequently inserted.