SU737160A1 - Machine for resistance spot capacitor microwelding using a hand tool - Google Patents

Description

voltage stabilization, charging device 2, discharge device 3, performing a cycle of heating-welding, a welding transformer 4, a hand-held welding tool 5 with an adjustment and dosing unit for compressing force of the electrodes of the welded parts 6, working capacitors 7, a matching transformer 8, thyristor 9, capacitor 10, first controlled key element

11, of the second controlled key element 12. The charging device 2 and the matching transformer 8 are connected to the source 13 of the AC supply voltage. The voltage adjustment and stabilization unit contains two series-connected threshold voltage elements. The manual welding tool 5 contains a microswitch with a normally open contact, which is triggered when the specified compression force is reached by the electrodes of the parts to be welded 6.

Matching transformer 8, thyristor

9 and capacitor 10 are switched on and in series with each other. Condenser output

10 through the first key element 11 is connected to the control input of the discharge device 3, the output after the second threshold element of the voltage regulating and stabilizing unit and connected to the control input of the charging device 2 and through the second key element 12 is connected to the control input of the thyristor 9 .

The output of a microswitch with a normally open contact of a manual welding tool 5 is connected to the control input of the first key element 11, which opens when a signal appears on its control input, and to the control input of the second key element

12, which closes when a signal appears at its control input.

Charger 2 is connected to working co-capacitors 7 connected via discharge device 3 to the primary winding of the welding transformer 4. The secondary winding of the welding transformer 4 is connected via electrodes of the hand welding tool 5 to the parts to be welded 6.

Maschina For point contact condenser microwelding manual tool works as follows.

When the supply voltage from the source of the supply voltage of the alternating current 13 to the input of the charging device 2 is applied, the working capacitors 7 are charged to a predetermined voltage level. The regulation and stabilization of the voltage on the working capacitors 7 is carried out by the voltage regulating and stabilizing unit 1 using the first and second threshold voltage elements.

When charging working capacitors 7 to

a predetermined voltage level at the output after the second threshold voltage element of the voltage regulation and stabilization unit appears a signal arriving at the input of the charger and the input of the second key element 12.

Charger 2 stops charging the working capacitors 7. The level of the capacitor on the working capacitors enters

to the measuring input of the voltage adjustment and stabilization unit. When lowering on the working capacitors 7 below a predetermined signal at the output after the second key element of the voltage of block I

voltage regulation and stabilization disappears, and the charger begins charging the working capacitors 7 to a predetermined level.

In the absence of a signal on the control

the input of the second key element 12, which takes place when the contact of the microswitch of an efficient welding tool 5 is normally open (the electrode electrodes of the manual welding tool are inoperative), the second key element 12 is in the open state and the signal from its input goes to its output connected to the thyristor 9 control input 9. The thyristor 9 opens and the capacitor 10 is charged to a voltage that is determined by the secondary winding of the matching transformer 8. When the capacitor 10 is fully charged, the thyristor 9 automatically closes even when present

signal at its control input. Since the capacitor capacitance is small, it is charged from the matching transformer 8 for one or more alternating current periods.

When, when compressed by the electrodes of a handheld welding tool 5 of the parts to be welded 6, the force reaches the root of the spot-blind value, the microswitch integrated in the handheld welding device is activated.

tool 5, and at its output a signal arrives at the control input of the first key element 11. The first key element 11 opens and the capacitor 10 through the key element 11

It is connected to the control input of the discharge device 3. In this case, the full discharge of the capacitor 10 occurs, the discharge device 3 is turned on, and the thyristor of the discharge circuit of the working capacitors 7n is opened, a thermal heating-welding cycle is performed. At the end of the preheating, the working capacitors 7 are discharged to the welding transformer 4. The preheating is carried out by means of a nonlinear saturable throttle, which is part of the discharge device 3.

When the electrodes of the manual welding tool 5 are pressed, the welding cycle “heating - welding is impossible,

since the control input of the second key element 12 receives a signal from the microswitch output of the manual welding tool 5. The second key element 12 is in the closed state, and the signal from its input does not arrive at its output connected to the thyristor control input 9 The thyristor 9 is in the closed state, and the charge of the capacitor 10 is impossible, as a result of which the signal of the first input of the key element 11 is not received on the control unit 1 of the gated device 3.

When releasing the electrodes of the hand welding tool 5, the microswitch of the hand welding tool returns to its original state, the signal from its output is removed, the first key element 11 is closed, and the second key element 12 is opened. At the first occurrence of the signal from the output after the second threshold voltage element of the voltage regulating and stabilizing unit, which occurs when the set voltage level is reached on the working capacitors 7, the thyristor 9 opens and the capacitor 10 charges and the circuit is prepared for the repeated welding cycle “Heating - welding.

The parts are welded by a current pulse induced in the secondary winding of the welding transformer 4 when the working capacitors 7 are discharged onto its primary winding.

In manual welding tools, the adjustment of the compression force of the electrodes and the automatic switching on of the welding current are achieved to achieve the preset compression by the electrodes of the welded parts 6 and the specified voltage on the working capacitors 7.

The machine for spot contact condenser micro welding with hand tools, distinguished by its simplicity and reliability, allows to obtain high-quality welds due to stability during each welding operation, compression force and electrical energy accumulated in working capacitors, due to the use of a combined thermal cycle "heating-welding, as well as by matching the maximum performance of the installer with the manufacturer's capacity to charge a working capacitor. The latter allows automatic control of the maximum permissible frequency of welding impulses.

Claims (2)

1. USSR author's certificate No. 251114, cl. B23K 11/26, 1969. 2. Information newsletter number 42 (1079) of the Institute of Electric Welding. E. O. Paton of the Ukrainian Academy of Sciences. Mashiia SSPI-1 for dotted contact condenser micro welding by hand and tool, 1977 (prototype).