| (19) |
 |
|
(11) |
EP 0 247 752 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
03.08.1988 Bulletin 1988/31 |
| (43) |
Date of publication A2: |
|
02.12.1987 Bulletin 1987/49 |
| (22) |
Date of filing: 11.05.1987 |
|
|
| (84) |
Designated Contracting States: |
|
CH DE FR IT LI NL |
| (30) |
Priority: |
12.05.1986 GB 8611510
|
| (71) |
Applicant: Rawson, Francis Frederick Hamilton |
|
() |
|
| (72) |
Inventors: |
|
- Rawson,Francis Frederick Hamilton
()
- Wilson,Brian
()
|
|
| |
|
| (54) |
Method of tuning an ultrasonic device, ultrasonic device and machine for performing
an ultrasonic tooling operation |
(57) To ensure that an ultrasonic tool is driven at an optimum frequency, the phases of
the voltage applied to the tranducer and the current flowing through the tranducer
are compared, and an error signal is generated dependant upon the divergence of the
phase difference from a desired difference, which may be zero phase difference. The
error signal is functional to vary the frequency at which the ultrasonic device is
driven, in the direction to reduce the error signal, so that the ultrasonic device
can be driven at zero error signal (i.e. the desired current/voltage phase relationship)
and thus at maximum efficiency.