Abstract: The invention concerns a control apparatus for machines designed to operate on a workpiece. The apparatus comprises a programming element consisting of a disc which has concentric tracks of varying transparency or reflectance; an optical scanner comprising an emitter unit emitting light beams to the programming element and a receptor unit for the light beams which have been transmitted or reflected; drive means for rotating the disc by the relative displacement of a tool and the workpiece; and an electric circuit connected to the receptor unit and to a motor for controlling the speed of rotation of the motor as a function of the intensity of the signal given by the receptor unit. The apparatus is applicable in particular to machines for working on plates, pieces of glass or plastics material, for example window panes, plate glass or lenses.

Abstract: The invention provides an arrangement for delivering to a work table a workpiece to be machined on that table and for removing the workpiece after it has been machined. The arrangment includes three endless conveyors in a line, of which a central, non-driving conveyor is fixedly mounted on the table between an upstream conveyor and a downstream conveyor. The upstream conveyor and the downstream conveyor are mounted on frames separate from the table and are designed for displacement between a position in which they are both remote from the central conveyor and a position in which they are both adjacent the central conveyor. The upstream and downstream conveyors rotate the central conveyor when in their adjacent position. Retractable retaining means position the workpiece received on the central conveyor and hold it on the work table throughout the entire machining operation. Means are provided for lowering the central conveyor from the workpiece during the machining operation.