| # | Country | Total Patents | |
|---|---|---|---|
| #1 | United States | 6 | |
| #2 | Austria | 1 | |
| #3 | Switzerland | 1 | |
| #4 | Denmark | 1 | |
| #5 | Spain | 1 | |
| #6 | United Kingdom | 1 |
| # | Industry | |
|---|---|---|
| #1 | Electrical machinery and energy | |
| #2 | Machines | |
| #3 | Computer technology | |
| #4 | Mechanical elements |
| # | Technology | |
|---|---|---|
| #1 | Spark gaps and corona devices | |
| #2 | Unspecified technologies | |
| #3 | Nails | |
| #4 | Analogue computers |
| # | Name | Total Patents |
|---|---|---|
| #1 | Duffy Charles Hugh | 9 |
| #2 | Charles Hugh Duffy | 1 |
| Publication | Filing date | Title |
|---|---|---|
| US1301824A | Spark-plug. | |
| US1284263A | Method for retaining inserts in spark-plug electrodes and the like. | |
| US1260884A | Spark-plug. | |
| US1161381A | Calculator. | |
| GB191301281A | Improvements in Spark Plugs. | |
| US1190130A | Spark-plug. | |
| US1067791A | Spark-plug. |