METHOD OF CHECKING METAL EXPULSION IN RESISTANCE WELDING

• US 3,591,764 A
• Filed: 02/24/1969
• Issued: 07/06/1971
• Est. Priority Date: 02/24/1969
• Status: Expired due to Term

• Current Assignee: Taran Jury Matveevich, Vorona David Solomonovich
• Original Assignee: Taran Jury Matveevich, Vorona David Solomonovich
• Inventors: TARAN JURY MATVEEVICH, VORONA DAVID SOLOMONOVICH
• Application Number:
  US04/801,531
• Time in Patent Office: 862 Days
• US Class Current: 219/90
• CPC Class Codes: B23K 11/25 Monitoring devices

Abstract

The present invention concerns a method and device for detecting metal expulsions in resistance welding wherein mechanical or electric change occurring in the welding zone are utilized for the estimation of time and quantity parameters of the expulsion.

Claims

1. A device to carry into effect the method of detecting the expulsion by a voltage gradient, comprising:

a differentiating RC circuit connected to the working electrodes of the welding equipment and converting the voltage gradient on the workpieces into electric signals;

an electric band-pass filter coupled to the output of said RC circuit and separating the electric signals characterizing the expulsion;

an electric amplitude-time selector of the signals separated by the filter, which selector is coupled to the output of said filter, and produces pulses whose parameters define the intensity and the time of appearance of the expulsion with respect to the time of action of the welding current;

a generator connected to said selector, this generator shaping gate pulses with a duration equal to that of the welding current, and controlling the work of said selector.

2. A device for detecting the expulsion by a shock wave during resistance welding, comprising:

a converter of the shock wave mechanical energy into electric signals, said welding being accomplished with a welding device including working electrodes carrying a welding current said converter being connected to one of the working electrodes of the welding device;

an electric band-pass filter coupled to the output of said converter for separating the electric signals representing the expulsion, a signal selector coupled to the output of said filter and producing pulses whose parameters define the intensity and time of appearance of the expulsion with regard to the time of action of the welding current;

a generator of gating pulses, said gating pulses having a pulse duration equal to that of the duration of the welding current, said generator being connected to said signal selector for controlling its operation.

3. A device for detecting the explusion by a shock wave during resistance welding, comprising:

a converter of the shock wave mechanical energy into electric signals, said welding being accomplished with a welding device including working electrodes carrying a welding current said converter being connected to one of the working electrodes of the welding device;

an electric band-pass filter coupled to the output of said converter for separating the electric signals representing the expulsion, a plurality of amplitude-time selectors, each of said amplitude-time selectors being coupled to the output of said filter, said selectors producing pulses whose parameters define the intensity of the expulsion and the time of their appearance with respect to the time of action of the welding current;

a plurality of generators of electric pulses, respective ones of said generators being coupled to only one of said plurality of selectors for shaping gate pulses of a preset duration, the total duration of the pulses of said generators being equal to the welding current duration, said plurality of generators being equal in number of said plurality of selectors.

4. A method for detecting the metal expulsion in resistance welding where the welding zone undergoes electrical and mechanical changes comprising converting said electrical and mechanical changes into an electrical signal and measuring said electrical signal to determine the moment of formation of the weld and the intensity of the metal expulsion.

5. A method for detecting as set forth in claim 4, wherein said converting is accomplished with piezoelectric means.

6. A method for detecting as set forth in claim 4, including the steps of supplying a pulse of a predetermined duration for actuating said resistance welding, and separating background noise from said eleCtrical signal during said predetermined time duration.

7. A method for detecting as set forth in claim 8, wherein said measuring step includes the steps of registering the commencement of said electrical signal with respect to the commencement of said pulse.