Abstract:
A grinding liquid trough arrangement for a grinding machine having a grindstone, wherein said grinding liquid trough arrangement comprises: a trough for grinding liquid formed by a trough wall, wherein the trough is configured to be arranged at a grinding machine having a grindstone such that the trough encloses a portion of a grindstone, wherein, the trough wall comprises at least one metal element which is attractable to magnets, and that,
       the grinding liquid trough arrangement comprises at least one magnetic element which is configured to be detachable attached to an external side of the trough wall by means of magnetic attraction between the magnetic element and the metal element.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure relates to a grinding liquid trough arrangement for a grinding machine having a rotational grindstone. The present disclosure further relates to a trough for grinding liquid and to a scraper for collecting particles from the bottom of a grinding liquid trough. 
       BACKGROUND ART 
       [0002]    Grinding or sharpening of edged tools, such as handheld knives or wood working tools such as plane irons, wood chisels or spoke shave blades may be performed in a bench type grinding machine comprising a motor driven rotational grindstone. During sharpening, the edged tool is held with a correct angle in contact with the grindstone and is moved across the grindstone by an operator until sufficiently sharpened. To cool the edged tool during sharpening, the grindstone is wetted with grinding liquid. For this purpose the grinding machine comprises a trough for the grinding liquid, typically water, arranged underneath the grindstone. 
         [0003]    A problem related grinding machines of the aforementioned type is to handle the small steel particles that are ground from the blade during sharpening. These particles accumulate in the grinding liquid during grinding and may as a consequence therefore slowly be incorporated into the surface of the grindstone over time. 
         [0004]    This problem has been addressed in the past. 
         [0005]    EP2883655A1 shows a grinding machine of the bench which is provided with a grinding jig for holding a knife in proper position against the grindstone during grinding. To collect steel particles ground from the edge of the knife, the grinding jig comprises a magnet. 
         [0006]    Attempts have also been made remove steel particles from the grinding liquid by incorporating a magnet in the trough for grinding liquid. However, while this solution has proven useful it is often found cumbersome and time consuming to clean the grinding liquid trough from steel particles after use of the grinding machine. 
         [0007]    Thus, it is an object of the present disclosure to provide a grinding liquid trough arrangement for a grinding machine which solves or at least mitigates one of the aforementioned problems. In particular it is an object of the present disclosure to provide a grinding liquid trough arrangement for a grinding machine which allows for simple cleaning of the trough for grinding liquid. Moreover, it is an object of the present disclosure to provide a grinding liquid trough arrangement for a grinding machine which allows for complete and through cleaning of the grinding liquid trough with a minimum of manual labor. 
       SUMMARY OF THE INVENTION 
       [0008]    According to the present disclosure at least one of these objects is met by a grinding liquid trough arrangement  10  for a grinding machine  100  having a grindstone  104  which is arranged to be rotated in a direction of rotation, wherein said grinding liquid trough arrangement  10  comprises: 
         [0009]    a trough  20  for grinding liquid formed by a trough wall  21 ,  22 ,  23 ,  24 ,  25 , wherein the trough  20  is configured to be arranged at a grinding machine  100  having a grindstone  104  such that the trough  20  encloses a portion of a grindstone  104 , characterized in that the trough wall  21 ,  22 ,  23 ,  24 ,  25  comprises at least one metal element  30  which is attractable to magnets, and that, 
         [0010]    the grinding liquid trough arrangement  10  comprises at least one magnetic element  40  which is configured to be detachable attached to an external side of the trough wall  21 ,  22 ,  23 ,  24 ,  25  by means of magnetic attraction between the magnetic element  40  and the metal element  30 . 
         [0011]    During grinding, the magnetic element may be attached to the external surface of the trough for grinding liquid by magnetic attraction to the metal element comprised in the trough wall. This will have the effect that magnetism is lead from the magnetic element to the metal element and through the wall of the trough for grinding liquid. The steel particles produced during grinding will therefore be attracted to the magnetized area of the trough for grinding liquid and adhere to the inner surface of the trough. 
         [0012]    After completed grinding, the detachable magnetic element may be removed from the external trough wall which in turn results in that the steel particles fall down onto the bottom of the trough since no magnetism now acts on the trough. The steel particles thereby gather in a neat pile on the bottom of the trough and may easily be collected and removed by the user of the grinding machine. 
         [0013]    Preferably, said at least one metal element  30  comprises iron or ferritic steel. 
         [0014]    Preferably, the magnetic element  40  is a permanent magnet. 
         [0015]    The trough wall may comprise a bottom wall  25  and a circumferential wall  21 ,  22 ,  23 ,  24 , wherein said at least one metal element  30  is arranged in the circumferential wall  21 ,  22 ,  23 ,  24 , close to the bottom wall  25 . 
         [0016]    It is preferred to arrange the metal element close to the bottom of the trough since the concentration of the relatively heavy steel particles in the grinding liquid is large at the bottom of the trough. 
         [0017]    The circumferential wall  21 ,  22 ,  23 ,  24  may comprise a first side wall  23  configured to face a grinding machine  100  and opposite front and rear walls  21 ,  22  extending from the first side wall  23 , wherein said at least one metal element  30  is arranged in the front wall  21  or the rear wall  22 . 
         [0018]    It is preferred to arrange the metal element in either of the front or rear wall since steel particles will be transported by the grindstone to the front wall and by the flow in the grinding liquid to the rear wall. 
         [0019]    Preferably, the trough  20  for grinding liquid is configured to be attached to a grinding machine  100  such that the first side wall  23  faces the grinding machine and such that the front wall  21  is positioned in a direction of rotation of a grindstone  101  of the grinding machine  100 , whereby said at least one metal element  30  is arranged in the rear wall  22 . 
         [0020]    It is preferred to arrange the metal element in the rear trough wall which, with respect to the direction of rotation, is behind the grindstone since the rotation of the grindstone will cause the grinding liquid to flow from the front wall towards the rear wall of the trough. The steel particles will follow the flow of the grinding liquid and collect at the rear wall of the trough from grinding liquid. 
         [0021]    Preferably the grinding liquid trough arrangement  10  comprising a scraper  50  for collecting particles from the trough  20  for grinding liquid, said scraper  50  having a scraping portion  51  and a handle portion  52 , wherein the handle portion  52  may comprise the magnetic element  40 . 
         [0022]    A scraper is a preferred tool for removing the steel particles from the trough for grinding liquid, since the tight contact between the scraping portion of the scraper and the bottom of the trough allows for complete removal of particles. By arranging the magnetic element in the handle portion of the scraper it is avoided that the steel particles adhere to the scraping portion, thereby making it easy the wipe the steel particles of the scraper after use. The combination of scraper and magnet is further very advantageous because by necessity the scraper is held in place at the trough during grinding. This minimizes the risk of the scraper getting lost between use thereof. 
         [0023]    The trough wall  21 ,  22 ,  23 ,  24 ,  25  may comprise a recess  60  for receiving the scraper  50 , wherein the shape of the recess  60  corresponds to the shape of the scraper  50  and comprises a scraping shaped portion  61  and a handle shaped portion  62 , whereby the metal element  30  is arranged in the through wall  21 ,  22 ,  23 ,  24 ,  25 , in the handle shaped portion  62  of the recess  60 . 
         [0024]    It is thereby ensured that the magnetic element always is in correct position with respect to the metal element in the though wall. 
         [0025]    Preferably, the recess  60  for receiving the scraper is configured such that the handle shaped portion  62  is close to a bottom wall  25  of the trough  20  for grinding liquid. 
         [0026]    A second aspect of the present disclosure is a trough  20  for grinding liquid for a grinding machine  100  having a grindstone  104  which is rotational in a direction of rotation, wherein said trough  20  is formed by a trough wall  21 ,  22 ,  23 ,  24 ,  25  and configured to be arranged at a grinding machine  100  having a grindstone  104  such that the trough  20  encloses a portion of a grindstone  104  characterized in that the trough wall  21 ,  22 ,  23 ,  24 ,  25  comprises at least one metal element  30  that is attractable to magnets. 
         [0027]    Preferably, the through wall  21 ,  22 ,  23 ,  24 ,  25  comprises a recess  60  for receiving the scraper  50 , wherein the shape of the recess  60  corresponds to the shape of the scraper  50  and comprises a scraping shaped portion  61  and a handle shaped portion  62 , whereby the metal alley element  30  is arranged in the through wall  21 ,  22 ,  23 ,  24 ,  25 , in the handle shaped portion  62  of the recess  60 . 
         [0028]    A third aspect of the present disclosure is a scraper  50  for collecting particles from a trough  20  for grinding liquid having a bottom wall  23 , wherein said scraper  50  comprises: 
         [0029]    a scraping portion  51 , configured to collect particles from the bottom wall  23  of the trough  20  by scraping and; 
         [0030]    a handle portion  52  for allowing a operator to grip the scraper  50 , wherein the handle portion  52  of the scraper comprises a magnetic element  40 . 
         [0031]    A fourth aspect of the present disclosure is a grinding machine  100  comprising a grindstone  104  which is rotational in a direction of rotation and a motor for rotating the grindstone and a grinding liquid trough arrangement  10  according to the first aspect of the disclosure. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]      FIG. 1 : A schematically drawing of a grinding machine comprising a grinding liquid trough arrangement according to the present disclosure. 
           [0033]      FIG. 2 : A schematically drawing of a grinding liquid trough arrangement according to the present disclosure in a perspective exploded side view. 
           [0034]      FIG. 3 : A schematically drawing of a grinding liquid trough arrangement according to the present disclosure during cleaning of the trough. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0035]    The grinding liquid trough arrangement according to the present disclosure will now be described more fully hereinafter. The grinding liquid trough arrangement according to the present disclosure may however be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those persons skilled in the art. Like reference numbers refer to like elements throughout the description. 
         [0036]      FIG. 1  shows schematically a grinding machine  100  comprising a grinding liquid trough arrangement  10  according to a first preferred embodiment of the present disclosure. The grinding machine  100  is of the bench type, i.e. it is of a design that allows it to be placed on a table in a workshop and to be operated manually by a person. The grinding machine  100  comprises a housing  101 . The housing has a plane base  102  on which the grinding machine is supported. The grinding machine comprises a shaft  103  which is rotated by an electrical motor (not shown) enclosed in the housing  101 . The shaft  103  is provided to hold and rotate a grindstone  104  against which tools or blades are ground or sharpened. The grindstone is arranged to be rotated in a direction of rotation which is indicated by the dashed arrow  105 . In  FIG. 1  the direction of rotation in clockwise. However, alternatively the grindstone  104  may be arranged to be rotated in opposite direction, i.e. counter clockwise. 
         [0037]    The grinding machine  100  comprises a grinding liquid trough arrangement  10  according to the present disclosure. The grinding liquid trough arrangement  10  comprises a trough  20  for grinding liquid which is formed by, i.e. comprises, a bottom wall and a circumferential wall such that the trough, when arranged on the grinding machine  100  partially may enclose the grindstone  104 . The purpose of the trough  20  is to contain grinding liquid (not shown) to wet the grindstone. The trough  20  for grinding liquid is arranged to be mounted on, and dismounted, from the grinding machine  100 . The trough  200  and the grinding machine  100  may therefore be provided with attachments (not shown) for hanging the trough  20  onto the grinding machine. The trough  20  may also be supported at the grinding machine  100  on support bars  106  extending from the side of the grinding machine. 
         [0038]    The grinding liquid trough arrangement  10  according to the present disclosure will in the following be described with reference to the exploded view shown  FIG. 3 . 
         [0039]    The trough  20  has an elongated rectangular shape and comprises a circumferential wall formed by opposite first and second side walls  23 ,  24  and opposite rear and front end walls  21 ,  22 . The first side wall  23  is configured to be supported against the side of a grinding machine when the trough  20  is in mounted state and the second side wall  24  faces away from a grinding machine when the trough is mounted state. The rear end wall  22  and the front end wall  21  extend respectively between the first and second side walls  23 ,  24 . The trough  20  also comprises a bottom wall  25  which is obscured by the first side wall  23 . The circumferential wall  21 ,  22 ,  23 ,  24  and the bottom wall  25  constitute the trough wall  21 ,  22 ,  23 ,  24 ,  25 . 
         [0040]    It is obvious that the trough  20  may have other forms than the rectangular shape described above as long as the trough may be mounted on grinding machine to partially enclose and wet a grindstone. 
         [0041]    The trough is typically made of plastic material, such as ABS or PP. 
         [0042]    According to the disclosure, the trough wall comprises a metal element  30  which is attracted to magnets. That is, the metal element  30  comprises, or consists, of a pure metal or a metal alloy which in the presence of the magnetic field from a magnet will be drawn to the magnet. Typically, such metals or alloys are ferromagnetic materials. Typical examples of suitable materials are iron or ferritic steels, such as stainless ferritic steels. It is appreciated that the metal element itself is not magnetized. 
         [0043]    The metal element  30  may be in any suitable form, for example a metal plate such a washer as shown in  FIG. 2 . 
         [0044]    Preferably, the metal element  30  is incorporated in the trough wall  21 ,  22 ,  23 ,  24 ,  25 . The metal element may thereby be embedded into the trough wall during casting of the trough  20  by so called “cast-in”. Alternatively, the trough wall may comprise a slot  26  which allows the metal element to be inserted into the trough wall. It is also possible to attach the metal element onto the trough wall, for example by gluing or welding. However, to protect the metal element from corrosion and to ensure a smooth trough wall which is easy to clean it is preferred to arrange the metal element such that is fully enclosed within the trough wall. 
         [0045]    The position at which the metal element  30  is arranged in the trough wall  21 ,  22 ,  23 ,  24 ,  25  depends on the design of the trough  20 . However, it is preferred to arrange the metal element  30  in a position in the trough wall where the concentration of metal particles in the grinding liquid is high during grinding. Preferably, the metal element  30  it therefore arranged in the circumferential wall  21 ,  22 ,  23 ,  24  of the trough  20  and close to the bottom  25  of the trough  20 . By “close to the bottom  25 ” is meant that the metal element  30  may be arranged in a position adjacent to the bottom  20  or in a position on half of the height of the circumferential wall or anywhere between these positions. For example, the metal element  30  may be arranged in a position on a quarter of the height of the circumferential wall. The metal element  30  may also be arranged in the bottom  25  of the trough  20 . 
         [0046]    It is preferred that the metal element  30  is arranged on one of the front- or rear end walls  21 ,  22  of the trough  20 . When arranging the metal element  30  in the trough wall, consideration is preferably given to the direction of rotation of the grindstone since the rotating grindstone creates a flow of grinding liquid from an end wall positioned in the direction of rotation towards the opposite end wall. Retuning to  FIG. 1 , the front end wall  21  is positioned in the direction of rotation  105  of the grindstone and the flow of grinding liquid is therefore directed towards the rear end wall  22 . Since the flow of grinding liquid carries metal particles towards the rear end wall  22  it is favorable to arrange the metal element in the rear end wall  22 . Obviously, if the grindstone rotates in opposite direction, i.e. counter clockwise, it is favorable to arrange the metal element  30  in the front end wall  21 . 
         [0047]    The grinding liquid trough arrangement  10  further comprises a magnetic element  40 , which is configured to be attached to an external surface of the trough wall by magnetic attraction to the metal element  30  in the trough wall  21 ,  22 ,  23 ,  24 ,  25 . The magnetic element  40  may further be detached, i.e. removed from the external side of the trough wall. Attaching and detaching of the magnetic element  40  is preformed by hand of the user of the grinding liquid trough arrangement. 
         [0048]    Typically the magnetic element  40  is a permanent magnet having a magnetic field of such magnitude, i.e. strength, that the magnetic element  40  may be firmly attached on the external side of the trough wall  21 ,  22 ,  23 ,  24 ,  25 . The magnetic field is further of such magnitude that the field extends through the metal element  30  to the internal side of the trough wall to attract metal particles in a grinding liquid and cause these to collect and adhere to the internal side of the trough wall. 
         [0049]    The magnetic element  40  may have any suitable form. For example, it has the same shape and dimensions as the metal element  30 . It may also have a contour corresponding to external side of the trough wall  21 ,  22 ,  23 ,  24 ,  25 . 
         [0050]    The grinding liquid trough arrangement  10  according to the present disclosure may also include a scraper  50 . The scraper  50  comprises a scraping portion  51  which is adopted to collect particles from the bottom  25  of the trough  20  by scraping. Thereby it is preferred that the width of the scraping portion  51  of the scraper corresponds to the width of the bottom  25  of the trough  20 . A handle portion  52  is provided to allow a user to hold the scraper  50  by hand during scraping. 
         [0051]    The magnetic element  40  may be arranged in the scraper  50 . Preferably the magnetic element  40  is thereby arranged in the handle portion  52  of the scraper. Typically, the magnetic element  40  is thereby embedded into to the handle portion  52  of the scraper. 
         [0052]    The trough  20  may comprise a recess  60  with a shape corresponding to the shape of the scraper  50 , i.e. having a handle shaped portion  62  and a scraper shaped portion  61 . The depth of the recess  60  typically corresponds to the thickness of the scraper. When the scraper  50  is not in used for scraping it may be placed in the recess  60 . 
         [0053]    Preferably the metal element  30  is arranged in the trough wall  21 ,  22 ,  23 ,  24 ,  25  such that it is positioned in the handle shaped portion  62  of the recess  60 . The recess  60  is thereby designed such that the handle shaped portion  62  is close to the bottom  25  of the trough  20 . The scraper handle portion  52  may thereby comprise the magnetic element  40 . This arrangement ensures that the scraper  50  is secured from being displaced when not used for scraping and at the same time it is ensured that the magnetic element  40  are in correct position with regards to the metal element  30 . 
         [0054]      FIG. 4  shows the scraper  50  in a cleaning operation in which the scraper  50  removes particles from the bottom  25  of trough  20 . 
         [0055]    Although a particular embodiment has been disclosed in detail this has been done for purpose of illustration only, and is not intended to be limiting. In particular it is contemplated that various substitutions, alterations and modifications may be made within the scope of the appended claims. 
         [0056]    For example, it is possible to arrange further metal elements  30  than one in the trough wall  21 ,  22 ,  23 ,  24 ,  25 . It is thereby also possible to include more than one magnetic element  40  in grinding liquid trough arrangement  10  according to the disclosure. 
         [0057]    Moreover, although specific terms may be employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Furthermore, as used herein, the terms “comprise/comprises” or “include/includes” do not exclude the presence of other elements. Finally, reference signs in the claims are provided merely as a clarifying example and should not be construed as limiting the scope of the claims in any way.