Device for positioning and holding a lens mounting block mold

Claim 1

Device for positioning and holding in the proper location, on the convex face of an ophthalmic lens, a mould for casting, on said lens face, a metal block permitting the subsequent mounting of the lens equipped with said metal block in a predetermined position on the spindle of a spectacle-lens trimming and/or bevelling machine, said lens being observed, for positioning same, along a sighting axis and superposed to the fixed image of a cross-line centered to said sighting axis, this device comprising a base plate carrying a circular seat having its axis coincident with said sighting axis and adapted to receive the concave face of said lens; a mould support movable in relation to said base plate from a seat clearing position permitting the observation of said lens along the sighting axis to a moulding position permitting of bringing a mould into direct contact with the convex face of the lens; a mould movable in relation to said mould support and comprising a substantially flat bottom and a flexible lateral skirt surrounding said bottom and having a free edge adapted to engage the convex face of said lens and extending in a plane substantially parallel to said bottom; means for positioning said support in the moulding position, which are associated with guide means permitting a movement of translation of said support when said support is in tHe moulding position, parallel to the seat axis; first means for guiding said mould during rotational movements thereof about a first axis fixed in relation to said support, said first axis, in the moulding position of said support, being parallel to one arm of the image of the cross-line and secant and perpendicular to the seat axis; and second means for guiding mould during the rotational movements thereof about a second axis fixed in relation to said mould, said second axis being secant perpendicular to said first axis, the point of intersection of said first and second axes being located substantially in the plane containing the free edge of said mould skirt, and, in the moulding position of said support, on the seat axis proper.