Laboratory Disk Grinder, Replacement Grinding Disk and Use of a Grinding Disk

Abstract

The present disclosure relates to a laboratory wheel grinder and a method for plane grinding a lower side of specimens, in particular mounted specimens, as well as a replacement grinding disc for the laboratory wheel grinder and the use of a grinding disc in a laboratory wheel grinder, wherein the grinding disc is divided into a peripheral annular first surface and a central second surface arranged within the peripheral annular first surface wherein the upper surface of the carrier disc is covered with the abrasive only in the peripheral annular first surface so as to form a grinding peripheral annular first surface and a passive central second surface.

1 . Laboratory wheel grinder with a rotating grinding disc for the plane grinding of a lower side of mounted specimens, comprising:
 a device housing with a grinding disc mounting plate and a drive motor, by means of which the grinding disc mounting plate can be set in rotation,   a grinding disc having a carrier disc and an abrasive bonded with a bonding agent on an upper surface of the carrier disc, wherein the carrier disc of the grinding disc has an upper surface and a lower surface, and wherein the lower surface of the grinding disc can be detachably mounted on the grinding disc mounting plate,   wherein the grinding disc is divided into a peripheral annular first surface and a central second surface disposed within the peripheral annular first surface, wherein the upper surface of the carrier disc is coated with the bonded abrasive only in the peripheral annular first surface to form a grinding peripheral annular first surface and a passive central second surface.   
     
     
         2 . Laboratory wheel grinder according to  claim 1 ,
 wherein the abrasive means are formed by abrasive grit and, in the cross section of the grinding disc, the abrasive grit in the grinding peripheral annular first surface defines a common annular abrasive first surface of the grinding disc and the carrier disc of the grinding disc in the passive central second surface forms a central non-abrasive second surface of the grinding disc, and wherein, in a fresh unused condition of the grinding disc, the common annular grinding first surface of the grinding disc is higher than the central non-grinding second surface of the grinding disc.   
     
     
         3 . Laboratory wheel grinder according to  claim 2 ,
 wherein the difference in height between the common annular abrasive first surface and the central non-abrasive second surface ranges from 50 μm to 5 mm.   
     
     
         4 . Laboratory wheel grinder according to  claim 1 ,
 wherein the abrasive is formed by abrasive grit and, in the grinding peripheral annular first surface, the abrasive grit is bonded with the bonding agent in a plurality of layers, on the upper surface of the carrier disc.   
     
     
         5 . Laboratory wheel grinder according to  claim 4 ,
 wherein the abrasive layer is multi-layered and is self-sharpening in such a way that dull abrasive grit breaks out during the grinding process and fresh abrasive grit, emerges from an underlying layer to the surface.   
     
     
         6 . Laboratory wheel grinder according to  claim 1 ,
 wherein the abrasive is formed by abrasive grit and, in the grinding peripheral annular first surface, is printed with a bonding agent in a predefined pattern.   
     
     
         7 . Laboratory wheel grinder according to  claim 1 ,
 wherein the grinding disc is round and/or has an outer diameter of between 100 mm and 500 mm.   
     
     
         8 . Laboratory wheel grinder according to  claim 1 ,
 wherein the grinding peripheral annular first surface has an inner diameter D_i and an outer diameter D_a, wherein half of the difference between the inner diameter D_i and the outer diameter D_a corresponds to the radial width B_r of the grinding peripheral annular first surface and is between 240 mm and 20 mm.   
     
     
         9 . Laboratory wheel grinder according to  claim 1 ,
 wherein the grinding peripheral annular first surface has an inner diameter D_i and an outer diameter D_a, wherein the inner diameter D_i has a range of between 20 mm and 450 mm, and the outer diameter D_a has a range of between 100 mm and 500 mm.   
     
     
         10 . Laboratory wheel grinder according to  claim 1 ,
 wherein the carrier disc comprises a metal sheet or a plastic sheet, and/or wherein the abrasive consists of diamond particles.   
     
     
         11 . Laboratory wheel grinder according to  claim 1 ,
 wherein the grinding disc can be fastened with the lower side on the grinding disc mounting in a removably adhering manner.   
     
     
         12 . Laboratory wheel grinder according to  claim 1 ,
 wherein the device housing comprises a collection tray for cooling liquid and grinding abrasion, with the grinding disc mounting plate rotating in the collection tray.   
     
     
         13 . Laboratory wheel grinder according to  claim 1 ,
 wherein one or more specimens are inserted into a specimen holder and pressed against the grinding disc, and   wherein, in addition to the rotation of the grinding disc, the specimen holder rotates with the specimen or specimens during the grinding operation, and an edge region of the specimen or specimens extends radially inward beyond the grinding peripheral annular first surface during the rotation of the grinding disc and the specimen holder.   
     
     
         14 . Laboratory wheel grinder according to  claim 1 ,
 wherein the laboratory wheel grinder comprises a device head with a piston for fastening a specimen holder, with which one or more specimens inserted in the specimen holder are pressed onto the grinding disc with a predefined pressure force, and wherein the specimen holder is rotatable in order to simultaneously bring about a rotation of the specimen holder during the grinding process in addition to the rotation of the grinding disc, wherein the axes of rotation the grinding disc and of the specimen holder extend in a parallel offset manner.   
     
     
         15 . Laboratory wheel grinder according to  claim 1 ,
 wherein the grinding peripheral annular first surface has an inner diameter D_i and an outer diameter D_a, and wherein half of the difference between the inner diameter D_i and the outer diameter D_a defines the radial width B_r of the grinding peripheral annular first surface, and   i) in the case of an individual specimen, the radial width B_r of the grinding peripheral annular first surface is selected such that the diameter of the specimen protrudes internally beyond the inner diameter D_i, due to a radial displacement of the rotating specimen during the grinding process, or   ii) in the case of a specimen holder with a plurality of inserted specimens, the totality of the specimens defines an overall outer diameter D_g relative to the rotation of the specimen holder, and the radial width B_r of the grinding peripheral annular first surface is selected such that the overall outer diameter D_g projects internally beyond the inner diameter D_i, due to a radial displacement of the rotating specimen during the grinding operation.   
     
     
         16 . Method for the plane grinding of a lower side of mounted specimens with a rotating grinding disc or with the laboratory wheel grinder wherein:
 a grinding disc having a carrier disc and an abrasive bonded with a bonding agent on an upper surface of the carrier disc is used, and wherein the carrier disc of the grinding disc has an upper surface and a lower surface, wherein the grinding disc is larger than the specimen to be ground,   wherein the grinding disc is divided into a peripheral annular first surface and a central second surface arranged within the peripheral annular first surface, the upper surface of the carrier disc being covered with the abrasive only in the peripheral annular first surface so as to form a grinding peripheral annular first surface and a passive central second surface,   wherein one or more specimens are inserted into a specimen holder and pressed against the grinding disc, and   wherein, in addition to the rotation of the grinding disc, the specimen holder rotates with the specimen or specimens during the grinding operation and, during the rotation during the grinding operation, edge portions of the specimen or specimens extend inwardly beyond the grinding peripheral annular first surface and into the passive central second surface.   
     
     
         17 . Replacement grinding disc consisting of a carrier disc and abrasive grit bonded to the carrier disc with a bonding agent, prepared for use in the laboratory wheel grinder for the plane grinding of a lower side of mounted specimens according to  claim 1 ,
 wherein the grinding disc considerably larger than the specimen to be plane-ground, wherein the carrier disc of the grinding disc has an upper side and a lower side, and wherein the carrier disc can be detachably adhered with the lower side to a grinding disc mounting plate of the laboratory wheel grinder, and   wherein the grinding disc is divided into a peripheral annular first surface and a central second surface arranged within the peripheral annular first surface, wherein the upper surface of the carrier disc is coated with the abrasive grit as abrasive only in the peripheral annular first surface, so that a grinding peripheral annular first surface and a passive central second surface are formed.   
     
     
         18 . Use of the replacement grinding disc according to  claim 17  in the laboratory wheel grinder according to  claim 1 .