Planar grinder

Abstract

A sample grinder includes a base having a bowl and a rotating drive plate to operably support a grinding wheel. A head is configured to support a specimen holder and has a first drive for rotational drive of the specimen holder and a second drive for moving the head and specimen holder toward and away from the drive plate. The head has a sleeve that is larger than the specimen holder. A cover is disposed over the bowl and has an opening larger than the sleeve so that the sleeve fits through the opening when the specimen holder is moved toward the rotating drive plate. The grinding wheel is mountable to the plate in a single radial orientation only. A dressing system is operably connected to a controller to monitor the current of the drive plate motor and/or the and the head first drive actuates the dressing system based upon the current drawn by the drive plate motor and/or the head first drive motor falling below a predetermined value.

What is claimed is: 
     
         1 . A sample grinder, comprising:
 a base having a bowl and a rotating drive plate to operably support a grinding wheel;   a head configured to support a specimen holder and having a first drive for rotational drive of the specimen holder, the head having a second drive for moving the head and the specimen holder toward and away from the rotating drive plate, the head having a depending sleeve having inner and outer peripheries, the inner periphery being larger than an outer periphery of the specimen holder; and   a cover disposed over the bowl and rotating drive plate, the cover having an opening having an inner periphery greater than the outer periphery of the sleeve, wherein the sleeve traverses through the cover opening when the specimen holder is moved toward the rotating drive plate.   
     
     
         2 . The sample grinder of  claim 1 , wherein the cover has a top, the top being non-planar and sloping away toward a front-side corner thereof. 
     
     
         3 . The sample grinder of  claim 1  wherein the sleeve is formed, at least in part, from a transparent or semi-transparent material. 
     
     
         4 . The sample grinder of  claim 1  wherein the cover includes a fluid delivery manifold and a plurality of fluid dispensing nozzles in fluid communication with the fluid delivery manifold. 
     
     
         5 . The sample grinder of  claim 4  wherein the fluid delivery manifold is formed as part of the cover and wherein the fluid dispensing nozzles are mounted to the cover over the fluid delivery manifold. 
     
     
         6 . The sample grinder of  claim 5  wherein the fluid dispensing nozzles are formed as openings in a plate and wherein the plate is mounted to an inside surface of the cover. 
     
     
         7 . The sample grinder of  claim 6  wherein the openings in the plate are asymmetrically disposed generally along a line of the plate. 
     
     
         8 . The sample grinder of  claim 5  including a fluid delivery conduit in the base in fluid communication with the fluid delivery manifold. 
     
     
         9 . The sample grinder of  claim 1  wherein the cover is removable from the base. 
     
     
         10 . The sample grinder of  claim 9  including a securing device to secure the cover to the base, the securing device movable between a secured position and an unsecured position, and wherein when the securing device is in the unsecured position, the cover is removable from the base without the use of tools. 
     
     
         11 . A sample grinder, comprising:
 a base having a bowl and a rotating platen to operably support a grinding wheel, the rotating platen having a central axis and one or more mounting elements thereon;   a grinding wheel having a central axis, the grinding wheel mountable to the platen and coaxial therewith, the grinding wheel mountable to the platen in a single radial orientation only, the grinding wheel having one or more mounting elements thereon cooperating with the platen mounting elements to permit mounting the grinding wheel in the single radial orientation only,   wherein the grinding wheel is initially mounted to the platen, removed from the platen and remounted to the platen, and when the grinding wheel is remounted to the platen, it can be remounted in only the same radial orientation as initially mounted to the plate.   
     
     
         12 . The sample grinder of  claim 11  wherein the platen mounting elements and the grinding wheel mounting elements are cooperating projections and recesses. 
     
     
         13 . The sample grinder of  claim 12  wherein the cooperating projections and recesses are pins and bores. 
     
     
         14 . The sample grinder of  claim 13  wherein the pins are positioned on platen and the bores are formed in the grinding wheel. 
     
     
         15 . The sample grinder of  claim 14  including four pins positioned on the platen, three of the pins being symmetrically disposed on the platen and the fourth pin being asymmetrically disposed on the platen relative to the three symmetrically disposed pins, the grinding wheel including four bores positioned to cooperate with the four pins. 
     
     
         16 . A sample grinder comprising:
 a base having a rotating drive plate to operably support a grinding wheel, the rotating drive plate having a drive plate motor operably connected thereto to drive the plate;   a head configured to support a specimen holder and having a first drive for rotational drive of the specimen holder, the first drive having a motor, the head having a second drive for moving the head and the specimen holder toward and away from the rotating drive plate;   a dressing system including an arm and a hardened face for contacting the grinding wheel to dress the grinding wheel;   a monitor for monitoring the current of one or both of the drive plate motor and the and the head first drive; and   a controller,   wherein the monitor monitors the current drawn by one or both of the drive plate motor and the head first drive, and wherein the dressing system is actuated based upon a the current drawn by one or both of the drive plate motor and the head first drive motor falling below a predetermined value.   
     
     
         17 . The sample grinder of  claim 16  wherein the controller determines whether a grinder cycle has commenced, and once commenced, the controller initiates a dressing operation is initiated. 
     
     
         18 . The sample grinder of  claim 17  wherein when the controller determines that a dressing operation is in progress, the controller monitors and captures current data points, and when the controller determines that a dressing operation is not in progress, the controller determines the predetermined value drive plate motor and the head first drive. 
     
     
         19 . The sample grinder of  claim 16  wherein the monitor monitors the current drawn by the drive plate motor. 
     
     
         20 . The sample grinder of  claim 16  wherein the monitor monitors the current drawn by the head first drive.