Method and apparatus for the non-destructive checking of spot welds between metal sheets produced by electric welding
US4887025A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 1988 |
| Grant date | Dec 12, 1989 |
| Priority date | — |
| Expiry date | Jan 11, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/20
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A electrical current of predetermined strength is passed through a spot weld by a first pair of electrodes. The electrical potential difference between two points, respectively upstream and downstream of the spot weld along the current path, is measured with a second pair of electrodes. In particular, this second pair of electrodes is used to carry out at least one first measurement before the application of the current, and at least one second measurement during the application of the current. These measurements are carried out at two instants separated by a time interval equal to or a whole multiple of the period of the main power voltage. The difference between the values measured in the first and second measurements provides an indication of the quality of the spot weld.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.