Abstract: A push-button and percussion type piezoelectric igniter, having a percussion mass comprising two diametrically opposite stubs displaceable on an incline provided for that purpose on the body of the push-button, a spring resting inside the body of the push-button and on the percussion mass respectively, for propelling the mass, a casing for receiving at one end the assembly comprising the push-button, spring and percussion mass, and at its other end the impact assembly comprising a striker, piezoelectric crystal, anvil, connection and locking part, wherein this casing comprises on its inside surface two diametrically opposite longitudinal grooves, and two apertures which are also diametrically opposite and slightly offset from said grooves receiving stubs of the percussion mass.

Abstract: A method of arc welding is disclosed. Specifically, a method of pulsed direct current (DC) arc welding is disclosed wherein special pulses of positive direct current are used to weld together work pieces. The special DC pulses are capable of dissipating difficult to reduce oxides which may be present on the surfaces of the work pieces without using a flux. The method is especially useful for fluxless arc welding of aluminum, particularly thin wall aluminum tubing used in making heat exchangers for air conditioning systems.

Abstract: Herein disclosed is a noncontact, nondestructive method for monitoring the quality of a high energy weld, e.g., laser beam weld. In accordance with the proposed method, an acoustic sensor (32) is positioned at a distance from the welding zone (34) and picks up airborne acoustic emission signals (33) associated with the laser welding process. These acoustic signals, propagating through the air space between the welding zone (34) and the sensor (32), are detected and analyzed (36,37) to determine the quality of the weld (FIG. 3).

Abstract: A resistance welder is provided having an electronic contactor, a welding transformer coupled in series with the electronic contactor, and a secondary circuit with a welding load connected to the welding transformer. The series circuit of the electronic contactor and the welding transformer is adapted for receiving power from an AC power source. The resistance welder also includes a control device having a voltage detector coupled to detect a voltage across the electronic contactor for producing a first signal according to the detected voltage, a delay circuit coupled to receive a primary voltage across the welding transformer for delaying the primary voltage by a value determined by a first time constant thereof to produce a voltage signal, a switch coupled to receive the first signal for resetting the delay circuit according to the first signal, and a gain control circuit coupled to receive the voltage signal for controlling a transmission gain of the voltage signal to produce a gain controlled signal.

Abstract: A pair of thermoplastic coated, paramagnetic metal sheets (26 and 27) are moved from a position within a first bus loop half (28) to a position within a second loop half (29) while a pair of electrodes (31 and 32) are cyclically moved to engage and weld a line of spots along the sheets. Constant current pulses are cyclically applied to the welding electrode (32) and through the loop halves (28 and 29) to the welding electrode (31). The current divides in the loop halves in proportion to the positionment of the metal sheets in the respective loop halves so that eddy current and hysteresis losses are held to constant minimum values. Auxiliary heaters (43 and 44) act to heat the electrodes to melt and displace the thermoplastic coating along the line of engaged spots prior to the cyclic application of the weld pulses.

Abstract: The quality of an electrical resistance spot weld is determined by monitoring the squeezing force applied through the electrodes to the workpieces by a force-transmitting device that exerts a squeezing force that varies when indentation of the workpieces occurs.

Abstract: This welding control method and apparatus automatically adjusts the percent heat of a welding machine in response to the duration of the preceding welds. The duration of each weld is measured by counting the line cycles. The line cycle count is compared with a percent heat increase condition and with a percent heat decrease condition of a preselected percent heat algorithm. The percent heat is incremented in response to the percent heat increase condition being met and the percent heat is decremented in response to the percent heat decrease condition being met. The control detects the weld resistance at the peak of each line cycle and compares the detected resistance with a resistance condition of a preselected resistance algorithm. The weld is terminated in response to the resistance condition being met and the cycle count being between a low limit count and a high limit count.

Abstract: An electrical welding device which requires no high frequency insulation and an electrical discharge gap for maintaining the arc discharge is made large. A main power source supplies an arc discharge current through an electrical conductor to the welding electrode. A high frequency electric power source applies a high-frequency high voltage between the electrode and the material to be welded to generate a high frequency discharge for arc ignition in the electric discharge gap. A high frequency magnetic choke element, which is preferably a plurality of stacked annular ferrite discs, surrounds a predetermined part of the electrical conductor. A high-frequency bypass capacitor is utilized to ground the electrical conductor between the magnetic choke element and the main power source.

Abstract: Apparatus for welding a workpiece using a gas tungsten welding arc and filler wire has three machine elements mounted on a base, to provide x, y, and z motions of a carriage part. A welding head is mounted on the carriage and is adapted to move in the z vertical direction and rotate without limitation, relative to the movable carriage. Thus, the head has five independent motions. The workpiece is mounted on a holder which provides x, y, and rotational motion beneath the welding head, to reposition the workpiece between actual welding operations. The apparatus which is controlled by two small computers is adapted to weld complex shaped workpieces.

Abstract: The solid state ignition system accurately controls the maximum primary winding current over a large range of operating voltages and selectively reduces its power consumption in response to a preselected ignition condition. The system includes an ignition transformer having a primary winding connected in series with a current regulator and a secondary winding connected with an igniter device for igniting an air-fuel mixture. A Darlington transistor is connected in series with the primary winding for blocking and permitting the flow of electrical current through the primary winding. A current regulating oscillator which controls the Darlington transistor alternately causes the transistor to be biased conductive and nonconductive. A comparator which is connected with the current sensor for sensing the primary winding current compares the sensed primary current with a preselected current.

Abstract: An automatic electrically operated protective system protects a welder from harmful light rays and sputtering emanating from the weld zone. An electric circuit controls a light shield means to assume either an open or closed condition. The electric circuit is responsive to the absolute value of the voltage between a welding electrode and a workpiece. A light shield opening signal is produced when this value is smaller than the electrode open circuit voltage but greater than the maximum electrode welding voltage upon ignition of the arc. A light shield closing signal is produced prior to the ignition of an arc when the aforementioned value is greater than the electrode to workpiece short circuit voltage and slightly smaller than the electrode open circuit voltage.

Abstract: The inductive elements in the background and pulse current portions of a pulse welding circuit are wound around separate cores and the background current path is connected in series with the pulse current inductive element to prevent damage to the background current switching element due to reverse voltage or current.

Abstract: In order to track a distinctive line on a workpiece area to be followed by an operating implement, specifically a junction line between two workpieces to be welded by a torch advancing along that line, a narrow beam is trained generally perpendicularly from a pulsating source of luminous radiation--e. g. a laser--upon that area and is shifted parallel to itself around the implement so as to intersect the workpiece area along a closed trace substantially bisected by the line being tracked. The source of radiation is part of a photosensor including an objective with an optical axis inclined to the beam at a small angle to generate an image of the latter on a slanting straight line parallel to a central ray which passes through the point of intersection of the beam axis with the front focal plane of the objective, this image line starting at the intersection of the rear focal plane with a central ray parallel to the beam.

Abstract: An arc-welding method comprises reciprocally moving a welding electrode substantially vertically toward a groove formed between objects of welding, in the width direction of the groove, following the face of the groove; producing, by a welding torch, an arc between the tip of the electrode and the groove; moving the torch vertically up and down so that one of an arc voltage and arc current of the arc agrees with a previously set value; continuously detecting the vertical position of the torch as a value of voltage indicated by a potentiometer; and reversing the direction of the movement of the torch in the width direction of the groove at the moment when the detected value of voltage agrees with a previously set value of voltage.

Abstract: A method for controlling a weaving path of a welding torch to trace a welding line in consumable electrode arc welding, including: detecting in a rightward weaving stroke of weaving motion a welding current level IL.sub.1 at the left end position of the weaving motion and a minimum current level IL.sub.2 during the period of the rightward weaving stroke and in a leftward weaving stroke of weaving a welding current level IR.sub.1 at the right end position of the weaving motion and a minimum current level IR.sub.2 during the period of the leftward weaving stroke; calculating the values of differential current (IL.sub.1 -IL.sub.2) and (IR.sub.1 -IR.sub.2) in the rightward and leftward weaving strokes, respectively; comparing and computing a disparity, if any, between the differential current values; and shifting the position of a median point of weaving motion according to the extent of the disparity in the differential current values.

Abstract: A power source for an arc welder which employs a high voltage, short duration impulse for periodically exciting an arc for use in arc welding. The device operates from an AC power source and employs a single silicon controlled rectifier (SCR) which is triggered in response to the output of a voltage controlled oscillator. The frequency of the voltage controlled oscillator is controlled by a programmer in conjunction with a feedback signal which is in accordance with the arc welding current, the output of the voltage controlled oscillator thus being varied as needed to maintain the welding current at the value programmed by the programmer. The output of the oscillator is divided down to produce a series of pulses which are used not only to trigger the SCR but also to trigger the arc starter and provide synchronization for the programmer. An inductor is used to commutate the SCR, i.e., cut the SCR off a predetermined time period after the triggering thereof.

Abstract: The primary winding of a welding transformer is provided with controlled rectifiers and the primary winding of a current transformer. The secondary winding of the current transformer is connected to a welding current pick-up. The phase angle of opening of the controlled rectifiers is varied through a phase shifter and a programmer. A pulse shaper is provided for shaping pulses synchronized with the voltage of a supply circuit and has an output connected to a phase delay unit. An OR circuit is provided having inputs connected to the output of the welding current pick-up and to one output of the programmer, and an output connected together with the output of the phase delay unit through AND logical circuits and an inverter to the inputs of a voltage switching flip-flop having outputs each being connected in pair with another output of the programmer through additional AND circuits to corresponding inputs of the phase shifter.

Abstract: In the electrical discharge machining of the surface of a recess in a workpiece electrode to a shape corresponding to that of a tool electrode, the electrodes are relatively displaced, during a finishing phase of machining, along an axis of penetration and simultaneously in a plane perpendicular to the axis of penetration with a cyclic translational movement whose amplitude increases with the penetration of the tool in the workpiece. This provides a virtual three-dimensional dilatation of the tool as it advances, and enables control of the sparking in both the frontal and lateral parts of the machining zone. The cyclic translational movements are obtained from a rotatable shaft having an axis parallel to the axis of penetration and an eccentric member cooperating with the rotatable shaft to slide relative to the shaft in a direction forming a predetermined angle with the direction of penetration, the eccentric member being rotated in unison with the shaft about its axis.

Abstract: A process and apparatus for achieving relative displacement between the electrode tool and the electrode workpiece of an EDM apparatus about a closed or looped path at a speed varying as a function of the machining gap width, such as to remove material from the machined surfaces at a substantially constant material removal rate.

Abstract: In electrical discharge machining, an electrode is displaced towards a workpiece at a rate controlled as a function of the sparking conditions. The relative position of the electrode and workpiece is measured and, beyond a preset .[.reference.]. relative position, advance of the electrode is slowed as a function of the displacement past the reference position, or is stopped at the reference position, while continuing sparking and allowing withdrawal of the electrode if necessitated by the sparking conditions.