Abstract: A mounting block for mounting a lens on a trimming and bevelling machine is made of flexible plastic material and adapted to be fixed onto one lens surface by means of a thin film of adhesive material; said block comprises orienting and driving means which cooperate with complementary means mounted on the spindle of the machine. The mounting block is formed with a flexible circular web portion having a conical lower surface which constitutes the lens-contacting surface, and which is provided with a recess in its central portion; the web portion is provided with at least one outwardly extending gripping tab adapted to facilitate the removal of the block from the lens.

Abstract: A mirror-orienting device for a laser levelling instrument utilizes an optical deflection system, a mirror which rotates about a fixed axis in the same plane as the mirror, a mirror lever fixed to the mirror at one end, a component for fine adjustment of rotation of the mirror, combined with a linear measurement indicator, which includes a measuring contact that moves axially. This allows the mirror to be oriented accurately, in relation to a reference direction, for example a horizontal or a vertical direction.

Abstract: A feeler for reading the contour of the rim of a spectacle frame has a reading head on a rod carried by a support which is linked by a ball joint to a fixed base. A cylindrical skirt on the support co-operates with the base and with a displacement detector which provides an indication which is employed to maintain contact of the rim with the reading head.

Abstract: A positioning and retaining plate assembly for the controlled location of a spectacle frame comprises three superposed plates slidably mounted in relation to each other. The upper plate, or tray, includes fastening means for a spectacle frame, and is slidable in one direction over the middle plate, or bed plate. The bed plate is slidable in a direction at right angles to the first direction over the lower plate, or base. Locking means are provided for locking the plates in position. The assembly may be mounted on a pedestal provided with a reflective upper surface on which reference axes are marked which can be viewed through apertures provided in the plates.