Abstract:
A welding comprises placing the end of a stud supported by a welding gun on a welding portion of a workpiece, producing an arc discharge across the stud and the workpiece, melting the end of the stud and a portion of the workpiece and bringing the end of the stud so as to abut on the melted portion of the workpiece. A hollow cylindrical member 21 is prepared so that the material has a larger inside diameter than an end 20 of a stud 19 and is made of a magnetic permeable material is prepared. During the arc discharge, the cylindrical member 21 is placed so that the hollow portion is positioned on the side of the workpiece opposite to the stud and corresponding to the end of the stud.
Abstract:
An arc shield is used in projection welding. The projection welding is performed for welding the lower end of a metal stud to the upper surface of a metal plate. The stud has a head and a stem connected securely to the central portion of the lower surface of the head. The arc shield includes an annular horizontal top wall defining a hole therein, and an annular vertical side wall having an annular top end connected securely to the outer peripheral portion of the top wall, and an annular bottom end having a plurality of notches. The annular side wall defines a chamber therein. The hole of the top wall has a size slightly greater than the diameter of the stem of the stud so as to allow for extension of the stem of the stud into the chamber through the hole of the top wall. When the projection welding is being performed, the electric arc is enclosed within the arc shield, while the surplus gas and molten metal that occur in the chamber flow from the arc shield through the notches of the annular side wall.
Abstract:
Control circuit for arc welding components to workpieces, in which a component is placed on to a workpiece by a weld gun and after a welding stroke is lifted from the workpiece in a return stroke by igniting a pre-current arc and is brought up to the workpiece again in a forward stroke during the burning of an interconnected welding arc, in which a sequencing control determines the tripping moments of return stroke and forward stroke as well as of the welding arc and a monitoring voltage is bypassed from the pre-current arc ignited at the welding point, characterized in that the monitoring voltage (V) is converted into a correction voltage (line 27) by means of a set-point comparator (25) and is superposed on a control voltage (line 18) for principally controlling a high-frequency modulated switching mode power supply unit (15) and said switching mode power supply unit (15), in accordance with the thus corrected control voltage, adjusts its output current (lines 13,14) during the respective welding operation to the resistance value of the pre-current arc established by the monitoring voltage (V) representing the respective welding data.
Abstract:
A method and apparatus is provided for attaching forging handles in the nature of studs to metal billets. The billets are passed in end-to-end relationship through a furnace following which the heated billets are individually delivered to a welding station where a welder welds a stud to the billet. The welder includes a welding head which is shifted by a translation mechanism from a feeding position where studs are successively fed to the welder to a welding position in which the stud is brought into engagement with the billet and electrical current is delivered through the stud to produce the weld.
Abstract:
The present invention relates to an arc-welding device for securing studs on metallic elements underwater, and comprising a head containing a chamber and of which the welding bead is obtained by means of a dielectric refractory ring placed around the base of the stud, wherein an annular space is provided between the stud and the ring and neutral gas is blown into the chamber through said space, to drive the water out of the chamber and keep up therein a gaseous atmosphere to facilitate the welding of the studs; the refractory ring is produced from borosilicate glass, rich in silica.
Abstract:
A stud welding method uses an inert mixed gas as arc shield in performing stud welding on a base metal, such as, vehicle body, by utilizing the stud, e.g. a T-stud, as an electrode, the stud serving as the positive pole while the base metal serves as the negative pole to thereby prevent formation of oxide film on the base metal surface during the welding, the inert mixed gas comprising carbon dioxide gas and argon gas.
Abstract:
Apparatus for indicating the time and welding current of a welding cycle is provided, along with means for monitoring the welding current and for preventing further welding cycles if the current is outside certain preset limits. The invention is used with stud welding apparatus in which a stud is placed against a workpiece, then withdrawn, and at the same time a pilot arc is formed; subsequently, a main welding arc is established which forms pools of molten metal on the stud and on the workpiece, the metal solidifying when the stud is subsequently plunged against the workpiece, thereby completing the weld. The length of time of the welding cycle and the welding current flowing during the existence of the main welding arc have, of course, heretofore been measured under laboratory conditions. However, such has not been accomplished under field conditions with commercial stud welding apparatus and particularly where such is accomplished by measuring both the welding time and welding current on a single meter. In a preferred form, the time and current values are stored through the use of relatively low-cost capacitors to make the invention even more practical. In addition, the average weld current is sensed after the weld is complete and further welds can be prevented if this current is not within certain limits.
Abstract:
In the machine disclosed, two flexible welding cables carry capacitor discharge current from a capacitor bank in a capacitor charging welding set and produce a movable electrical connection between a welding gun and a base material onto which a welding element is to be welded. Both welding cables are fixed with respect to one another. According to one embodiment of the invention the cables are arranged to be equidistant from one another substantially over their entire length. They are arranged as close as possible to each other within the breakdown limits of the insulation. The cables are of a predetermined length.
Abstract:
A temperature-compensating circuit which employs a voltage divider across a battery to be charged which has a thermistor in one leg thereof and a capacitor across the opposite leg thereof. The capacitor, on reaching a predetermined charge, supplies a gating pulse through a unijunction transistor to a silicon controlled rectifier which operates a relay for discontinuing charging of the battery. A relay in the discharge circuit of the welding apparatus senses welding current and breaks the current flow through the silicon-controlled rectifier to deenergize the relay and reset the circuit for recharging of the battery following partial discharge thereof. A capacitor in parallel with the relay maintains the relay energized a predetermined time to prevent recharging of the battery until the welding cycle is completed.