Patent ID: 11969848
Assignee: ESSILOR INTERNATIONAL
Field: Machine tools (Mechanical engineering)
Classification: CPC B | IPC B

Claim 16:
17. An optical-grade surfacing tool (10), comprising:
a base (11) comprising a rigid holder (12) and a flexible collar (13) encircling said rigid holder (12), said rigid holder (12) having a transverse end surface (14), and said collar (13) having a transverse end surface (15) that is located on a same side as the transverse end surface (14) of the rigid holder (12);
an elastically compressible interface (16) comprising a first transverse end surface (17), a second transverse end surface (18), and a lateral surface (19) extending from a periphery of the first transverse end surface (17) to a periphery of the second transverse end surface (18), the first transverse end surface (17) of the elastically compressible interface (16) being attached to the transverse end surface (14) of the rigid holder (12) and to the transverse end surface (15) of the collar (13); and
a flexible buffer (20) having a third transverse end surface (21) that is attached to the second transverse end surface (18) of the elastically compressible interface (16) and a fourth transverse end surface (22) that is configured to be applied against a surface (23) to be worked, said buffer (20) comprising a central portion (24) that is located plumb with the transverse end surface (14) of the rigid holder (12) and a peripheral portion (25) that is located transversely beyond the transverse end surface (14),
said peripheral portion (25) being joined to the holder (12) exclusively by said interface (16) and by said collar (13), and
said collar (13) being elastically deformable configured so that the tool (10) elastically deforms between a rest position in which the tool is free of any force applied for pressing the flexible buffer (22), and a reference position in which the second transverse end surface (22) of the flexible buffer (20) is pressed against a reference surface (37, 40, 46, 47) that is spherical with a radius ranging from 40 mm and 1500 mm,
wherein the collar (13) is subdivided into petals (27), and
wherein at every distance x from the far end of each petal (27), a thickness of the petal is smaller than:, h
    MAX
  
  =
  
    
      R
      ⁢
      
        
      
      ⁢
      
        σ
        MAX
      
    
    
      2
      ⁢
      E
    
  

with
σMAX being a tensile limit of a material of the petals,
E being an elastic modulus of the material of the petals, and
R being an inverse of a difference in curvature between the rest position and the reference position of the tool.