Abstract: A method and an apparatus for detecting and recording the number of phenomena, for instance of defects of a product continuously manufactured, wherein a graphic record is made on a recording tape in a direction transverse to the advancing direction of said recording tape and at a length corresponding to the sum of unit steps of which the number is equal to the number of phenomena occurring during a measuring or counting period, a fixed limited number of unit steps being executed and thereby a record of a fixed length produced upon failure of detecting means for said phenomena.

Abstract: A method and device for contactless measuring of the thickness of layers, particularly of insulating layers on metallic parts whereby a contactless pneumatic servo-mechanism approaches to and maintains a measuring head at a predetermined distance from the layer and whereby the thickness of the layer is ascertained by a measuring pick-up located in the measuring head.

Abstract: A device for positioning a part comprises a signal generator which, upon movement of said part within the vicinity of a required position of the part, produces a signal value which passes through zero at a point when said part is in said required position, and a servo system responsive to said signal value to transmit movement to said part until said signal value reaches zero. The signal generator may operate to define a predetermined stop position into which a part, for example a machine part or a workpiece, is to be moved, or, in cooperation with an appropriately movable member, it may be used to trace a predetermined pattern of movement so that the part to be moved follows said pattern.