Essilor International Cie Generale D'optique

Essilor International (Compagnie Generale D'optique)

Gerard Lombard

In this machining method using a multi-axis numerically-controlled machine, a workpiece holder (4) is rotated (rotation .alpha.) in step-by-step motion around an axis (Z), rectilinear movements are produced between a tool (3) and the workpiece holder (4) respectively along axes (Z and X), and in addition the tool (3) is rotated (rotation .beta.) around an axis (Y), these various movements being controlled in response to data corresponding to a required surface to be produced on a workpiece. The step-by-step rotating movement and the rectilinear movements are used for producing a spiral path of the tool on the surface of the workpiece to be machined, while the rotating movement (.beta.) is used to achieve the required thickness removed at successive points on the spiral path.

Method and multi-axis numerically-controlled machine for machining

A workpiece holder apparatus is disclosed for use with a surfacing tool for surfacing optical lenses having a surface of revolution especially afocal ophthalmic lenses. A workpiece holder comprises a chamber having an endwall, a sidewall and an open end, for receiving an optical lens. The chamber is connected in operation to a source of compressed air, and an air cushion is established between the endwall and the lens. There is radial clearance annularly between the edge of the sidewall and the edge of the lens. The air cushion is controlled by an annular projection protruding from the endwall, in cooperation with a facing portion of the lens. The entire workpiece holder is adapted to be fitted on a conventional fluid actuator for applying the lens against the surfacing tool.

Workpiece holder apparatus for surfacing optical lenses

A lens holder device is employed having a bell-shaped chamber, at least a portion of the sidewall of the chamber at an open end thereof having a circular section and adapted to accommodate with radial clearance a lens to be surfaced. A conduit communicates with the chamber and supplies pressurized hydraulic fluid into the chamber. The pressurized hydraulic fluid in the chamber forms a hydraulic cushion for the lens, and a hydraulic film flowing between the peripheral edge of the lens and the sidewall portion, the hydraulic film flowing out of the open end of the chamber.

Method and apparatus for surfacing optical lenses

This blocking apparatus for fixing a metal block to the finished face of a semi-finished spectacle lens blank by casting a low-melting metal into a mold contacting the finished face of the blank comprises a mold made of two sections, namely a fixed section and a movable section, the former carrying the annular seat for the lens blank and the latter carrying relief elements, these two mold sections being in mutual rotary contact through part-spherical surfaces constituting a ball-joint centered to the axis of the annular seat. Control means are operatively connected to a shaft rigid with the movable mold portion for orienting same and cause same to be lipped about the center of the ball-joint in order to impart the prescribed prism value and the prescribed prism axis orientation, and align the relief elements with the prescribed cylinder axis.

Blocking apparatus for fixing a metal block to the finished face of a

A hub is disclosed for mounting the spindle of a rotary tool, particularly a grinding or polishing wheel for ophthalmic lenses. The hub comprises a cylindrical bore and a plurality of radial centering arms arranged around the bore with their free ends lying in a common circle concentric with the axis of the bore. The centering arms each have a hinge or pivot which may be formed by a portion of reduced section at their bases. The pivot or hinge axes of the centering arms are tangent to another common circle concentric with the bore. Each of the centering arms is of elastically deformable construction fixed, or formed in one piece, with the rest of the hub. The hub is divided by a radial groove into a rigid, one-piece part and a deformable flange formed by the centering arms. A tightening ring with a preferably planar thrust or engagement face is adapted to apply an axial force against the centering arms so that they come into retaining engagement with the spindle.

Growing community of inventors

Velaines, France

Gerard Lombard