Block piece

Abstract

A block piece for holding an optical lens to be worked in a machine tool, the block piece having a rotational axis 1.1 , a holding surface that can be made to face the lens and a bearing surface that is directed radially outwards and can be brought to bear in a workpiece spindle, wherein the holding surface has at least one recess 1.2 a or a number of recesses 2.1 - 2.6 , which are distributed around the rotational axis 1.1 , have a diameter DA and serve for receiving bonding compound for adhesive bonding to the lens.

1 . A block piece for holding an optical lens to be worked in a machine tool, comprising: a rotational axis, a holding surface that can be made to face the lens and a bearing surface that is directed radially outwards and can be brought to bear in a workpiece spindle, wherein the holding surface has several recesses, which are distributed around the rotational axis, have a diameter DA and serve for receiving bonding compound for adhesive bonding to the lens,
 wherein at least three recesses are provided in the holding surface, distributed about the rotational axis, wherein   a) a ratio of the diameter DA of the recess in a radial direction to the rotational axis to a diameter DL of the bearing surface is between 0.1 and 0.3 and/or   b) a ratio of a depth TA of the recess in an axial direction to the rotational axis to a height H of the block piece is between 0.28 and 0.59 and/or   c) a ratio of the diameter DA of the recess in a circumferential direction to the rotational axis to a width B 1  of the web between the recesses is between 0.5 and 3.5.   
     
     
         2 . The block piece according to  claim 1 , wherein the diameter DA is at least 5 mm to 8 mm and/or at least four, five, or six recesses are distributed about the rotational axis. 
     
     
         3 . The block piece according to  claim 1 , wherein at least one recess is configured as a borehole and/or at least one recess is configured as a continuous or blind hole. 
     
     
         4 . The block piece according to  claim 1 , wherein the web with a width B 1  is provided between every two recesses, the width B 1  being between 4 mm and 10 mm in dimension. 
     
     
         5 . The block piece according to  claim 1 , wherein the recess has an undercut in relation to the direction of the rotational axis. 
     
     
         6 . The block piece according to  claim 5 , wherein the undercut is fashioned as a thread inside the borehole. 
     
     
         7 . The block piece according to  claim 5 , wherein the borehole has a borehole axis (a) and the borehole axis (a) is tilted relative to the rotational axis in order to form the undercut. 
     
     
         8 . A block piece for holding an optical lens to be worked in a machine tool, comprising: a rotational axis, a holding surface that can be made to face the lens and a bearing surface that is directed radially outwards and can be brought to bear in a workpiece spindle, wherein at least one recess fashioned as a groove is provided, being disposed concentrically to the rotational axis, while the holding surface and the recess serve to receive bonding compound for adhesive bonding to the lens,
 wherein a shoulder broadening the holding surface is provided adjacent to the bearing surface, with an end stop surface placed opposite the holding surface and able to bear axially against the work piece spindle, the shoulder having an outer diameter D with D>43 mm and the recess being disposed at least partly in the shoulder, while a diameter D 1  of the recess is at least 43 mm in size.   
     
     
         9 . The block piece according to  claim 8 , wherein the recess is disposed inside the holding surface and/or inside a side surface of the shoulder. 
     
     
         10 . The block piece according to  claim 9 , wherein one or more additional grooves are provided within the holding surface, forming an undercut, while the respective additional groove is tilted inward toward the rotational axis. 
     
     
         11 . The block piece according to  claim 10 , wherein the additional groove is circular or partly circular or spiral in shape. 
     
     
         12 . The block piece according to  claim 8 , wherein at least one groove is configured as a keyway or indexing groove opposite the holding surface with a width B 2 , while the groove is provided at a height of a web in relation to a circumferential direction. 
     
     
         13 . The block piece according to  claim 8 , wherein one end face of the holding surface has a radius of curvature R 1 . 
     
     
         14 . The block piece according to  claim 1 , formed from metal. 
     
     
         15 . A system consisting of a block piece according to  claim 1 , with a lens held against the block piece with a bonding compound. 
     
     
         16 . The block piece according to  claim 1 , wherein the ratio of the diameter DA of the recess in the radial direction to the rotational axis to the diameter DL of the bearing surface is between 0.20 and 0.27, and/or the ratio of the depth TA of the recess in the axial direction to the rotational axis to the height H of the block piece is between 0.41 and 0.56, and/or the ratio of the diameter DA of the recess in the circumferential direction to the rotational axis to the width B 1  of the web between the recesses is between 1 and 3.0. 
     
     
         17 . The block piece according to  claim 16 , wherein the ratio of the diameter DA of the recess in the radial direction to the rotational axis to the diameter DL of the bearing surface is around 0.25, and/or the ratio of the depth TA of the recess in the axial direction to the rotational axis to the height H of the block piece is around 0.53, and/or the ratio of the diameter DA of the recess in the circumferential direction to the rotational axis to the width B 1  of the web between the recesses is between 1.5 and 2.5. 
     
     
         18 . The block piece according to  claim 2 , wherein at least one recess is configured as a borehole and/or at least one recess is configured as a continuous or blind hole, and wherein the web with a width B 1  is provided between every two recesses, the width B 1  being between 4 mm and 10 mm in dimension. 
     
     
         19 . The block piece according to  claim 18 , wherein the recess has an undercut in relation to the direction of the rotational axis, wherein the undercut is fashioned as a thread inside the borehole, and wherein the borehole has a borehole axis (a) and the borehole axis (a) is tilted relative to the rotational axis in order to form the undercut. 
     
     
         20 . The block piece according to  claim 8 , wherein one or more additional grooves are provided within the holding surface, forming an undercut, while the respective additional groove is tilted inward toward the rotational axis.