| # | Country | Total Patents | |
|---|---|---|---|
| #1 | France | 6 | |
| #2 | United States | 4 | |
| #3 | South Africa | 3 | |
| #4 | Brazil | 2 | |
| #5 | United Kingdom | 2 | |
| #6 | Italy | 2 |
| # | Industry | |
|---|---|---|
| #1 | Consumer goods | |
| #2 | Control | |
| #3 | Measurement |
| # | Technology | |
|---|---|---|
| #1 | Representation of music | |
| #2 | Teaching materials | |
| #3 | Special musical instruments | |
| #4 | Time-interval measuring |
| # | Name | Total Patents |
|---|---|---|
| #1 | Del Castillo J | 8 |
| #2 | Del Castillo Juan M | 1 |
| Publication | Filing date | Title |
|---|---|---|
| ZA7505002B | Optical metronome | |
| US3803971A | Lighted optical metronome | |
| US3765294A | Teaching device for attachment to a keyboard instrument | |
| US3743758A | Optical metronome | |
| US3709085A | Teaching device for attachment to a keyboard instrument |