Abstract: A rotor which carries a transducer for a rotating-head device is fabricated from a substantially circular aluminum support means with a stretched length of stainless steel foil encircling its perimeter. The rotor is bonded together by anchoring stainless steel pins into the periphery of said aluminum supporting means and electron beam welding the stainless steel foil onto said stainless steel pins.

Abstract: Laser irradiation means for irradiating a target, wherein a single laser light beam from a source and a mirror close to the target are used with aperture means for directing laser light to interact with the target over a broad area of the surface, and for protecting the laser light source.

Abstract: Plasma MIG welding in which a plasma flow is generated between a non-consumable electrode and a workpiece, and a consumable electrode is fed through such plasma flow toward the workpiece to establish a MIG arc between the same. The current intensity in the plasma flow is increased by applying additional current thereto from an annular auxiliary non-consumable electrode surrounding the plasma flow and positioned between the primary non-consumable electrode and the workpiece.

Abstract: In a plasma-arc torch for melting metals the electrode assembly comprises an electrode holder made of copper alloys and having a butt portion which rigidly secures a tungsten electrode by means of diffusion welding. The invention provides for a welded joint between the electrode and the electrode holder, a nonconsumable current-conducting interlayer made of titanium, copper and tungsten being placed therebetween.

Abstract: This invention relates to a control system which comprises a sensor for monitoring a selected variable and providing an electrical signal which is a function of said variable; a reference source operable to provide a reference at an output thereof which varies over a predetermined time period; and a comparator circuit coupled to the sensor and the reference voltage source. The comparator circuit compares the electrical signal with said reference signal and provides a control signal in dependence upon the comparison.

Abstract: Laser beam welding apparatus comprising a body with a passage through which the laser beam is directed and focused to a position outside the body closely adjacent to a terminal portion of the passage. A second passage opens into the first to direct a transverse jet of shielding gas to sweep away the plasma formed during welding through an aperture in the opposite wall of the first passage. Since the welding zone is virtually enclosed by the body the incidence of air entrainment by the transverse jet of shielding gas is minimized.

Abstract: Laser micromachining apparatus for producing a selectable machining pattern on a workpiece, for example a substrate of paper or rubber or for producing a silicon integrated circuit. A high power laser beam carrying a controllable sequence of light pulses passes through a variable attenuator unit and then through a beam expander unit before impinging on a mask containing an enlarged pattern of the mark to be machined. The pattern in the mask consists of a suitable arrangement of small apertures. After diffraction through these apertures and focalization by a converging optical element, the laser light passes through an optical imaging unit which images the mask onto the workpiece to produce said selectable machining pattern thereon.

Abstract: In laser-beam welding apparatus, a gas jet from a first gas conduit is directed at plasma created by the interaction of the laser beam and the workpiece material, the gas jet being adapted to blow the plasma into the weld zone, a second gas conduit providing shielding gas at the region of the crossover of the laser beam and the plasma-control jet to reduce the possibility of contamination or porosity of the weld zone into which the plasma is blown.

Abstract: In the course of welding measurements are taken of the concentration of metallic vapor in the cloud of vapor over the welding zone, the diameter of the hot spot on the article being welded being kept constant. Said concentration serves as an indication of the depth of fusion. The metallic vapor concentration is measured with the aid of a device comprising an electron quantity transducer, for example, a beam trap, with an electric filter connected to its output, said electric filter separating electric waves of frequencies upwards of 200 Hz. The alternating component thus separated is converted into d-c voltage and compared to a reference signal in a comparison circuit, upon which the electron beam current of the gun is altered, depending on the value of the error signal of said comparison circuit. The depth of fusion is found by way of changing the value of the output signal of the rectifier.

Abstract: A coherent shape of a composition characterized by having a core bonded by regrowth of silicon carbide is produced by heating particulate silicon carbide which may be mixed with a minor amount of modifying agent, by means of an uncharged beam of energy, to a temperature above 3000.degree. F. and below 5500.degree. F. and subsequently cooling the resultant coherent shape below 3000.degree. F., both steps being completed within a period of 10 minutes. In the preferred method, unconsolidated particulate silicon carbide is exposed to the energy of a laser beam and the particulate silicon carbide has a particle size within the range of magnitude of 10 to 300 microns. Upon its initial formation, the shape has a core and a distinctly delineated rind which is attached to the core. The core has a relatively low resistivity as compared with the rind.

Abstract: The invention relates to an installation for surfacing by plasma-arc welding including in particular a plasma torch and a control and power supply device for the formation of a transferred arc between the electrode of the torch and the workpiece to be surfaced and of a non-transferred arc between the said electrode and the nozzle of the torch, the control and power supply device comprising a single d.c. source one terminal of which is connected to the electrode of the torch and the other terminal of which is connected, on the one hand, to the workpiece to be surfaced and on the other hand to the nozzle of the torch via a resistance. The plasma torch has at least two cooling systems supplied by a distribution device which is controlled as a function of the cooling water temperature and/or the electrical power consumption of the torch.

Abstract: A laser beam is directed towards a workpiece immersed beneath the surface of a liquid coolant. An exothermically reactive gas is directed through the liquid coolant to the workpiece under sufficient pressure and velocity to sweep away a sufficient amount of the liquid coolant to expose part of the workpiece to the laser beam for cutting.

Abstract: A beam welding apparatus useful for welding a plurality of workpieces spaced along a workpiece plane during a scan of the workpieces is disclosed. A scan light and a detection means are used to detect the location of each workpiece and to supply a signal for triggering a beam source into emission upon the detection of each workpiece. The beam and scan light sources are focused on the workpieces through the same focusing lens. Further, the apparatus comprises means for maintaining a constant optical path between the lens and each workpiece that includes a translating means for moving a moveable mirror, that is disposed between the lens and the workpieces, along a path coincident with the lens axis so as to effect consistent welds during an uninterrupted scan.

Abstract: An improvement in a plasma flame spraying apparatus, particularly one in which at least two gases form the plasma, which improvement comprises means associated with the plasma gas inlet, said means being time related to an increase in the current through the arc maintained in the plasma flame spray gun, said current and said means associated with the plasma gas inlet each independently being associated with a timing means whereby the full flow of a secondary gas through the nozzle of the gun and the electric arc established therein is substantially simultaneous with an establishment of a full current level through the electric arc through which said secondary gas passes; a fully automatic ignition system for a plasma gas flame spraying process whereby establishment of an optimum gas mixture for normal operation is time coordinated with respect to start-up of the current passing in the circuit of the electric arc in the gun, such that the current rise and rise of secondary gas flow through the gun occur within

Abstract: A method for irradiation of round-section cylindrical objects, such as pipes, with accelerated electrons, whereby three objects are placed together in the area of intersection of three ribbon or strip electron beams directed at an angle of 120.degree. to one another. The objects in the intersection area are positioned so that the centers of the cross sections thereof coincide with the apices of an imaginary equilateral triangle, and each side of the imaginary triangle being normal to the direction of one of the electron beams, and the length of each side is equal to at least two diameters of an object. The width of each ribbon beam is not less than a triangle side length plus the diameter of an object.

Abstract: Apparatus for controlling the supply of electric power to a power consuming appliance (e.g. an electric soldering iron) in dependence on a parameter (e.g. the temperature of the soldering iron) comprises electric circuit means including a thyristor connected in series with the appliance across an AC supply, a first voltage divider including a variable resistor for defining a set point for said parameter, a second voltage divider including a sensor for said parameter and adapted to provide an analogue electrical parameter, and a first and a second transistor having their bases connected respectively to tappings of said voltage dividers defined respectively by a terminal of said variable resistor and said sensor, the emitter of said second transistor being connected to the gate of said thyristor.

Abstract: A method and apparatus is provided for laser welding which utilizes the power reflected by the surface being welded to control the power input to the weld. A beam of laser light is projected on the surface to be welded and the power of the light reflected by the surface is measured by a wattmeter placed in the path of the reflected beam. The output from the wattmeter is used to control the laser power per unit area projected on the weld. In one embodiment the wattmeter output is used to control the speed of the skate motor which moves the surface being welded. In another embodiment, the wattmeter output is used to control the output of the laser.

Abstract: A method and device for controlling the power supplied to an a.c. powered load by zero-passage switching.A ripple voltage which is superimposed on the control voltage synchronizes the start of a sawtooth voltage in a small range on both sides of the zero passage of the power-supply sinewave for the load.The device is employed in electric heating systems.

Abstract: An optical laser beam chopper for converting a continuous beam into a series of scanning impulses for use in perforating a moving web is disclosed. The system utilizes a coherent light source which produces a beam for use in perforating a thin paper web of the type used in producing cigarette filters. The beam passes through a rotary chopper, or shutter, system which incorporates a plurality of rotary discs each of which carries one or more annular rings divided into segments. Selected segments on each ring are formed of a reflective material to act as mirrors for the laser beam, while the remaining segments are in the form of apertures which allow the beam to pass through the disc.

Abstract: A metal layer is clad to a metal substrate by laying spaced rods or wires of a cladding metal on the substrate surface and scanning the cladding metal with a continuously operating laser beam, part of which impinges directly on the cladding metal to melt it and part of which impinges on the adjacent surface area of the substrate to improve flow of molten metal thereon. The cladding metal may be fed to the substrate surface in synchronism with laser beam scanning. The process produces a clad layer of the cladding metal on the substrate characterized by a fine and homogeneous structure within the clad on layer and further characterized by uniform and high hardness compared to prior art cladding methods. The surface of the clad may be smoothed by locally oscillating the laser beam during the course of cladding and/or by multiple passes.