Average Co-Inventor Count = 4.00
ph-index = 2
The patent ph-index is calculated by counting the number of publications for which an author has been cited by other authors at least that same number of times.
Company Filing History:
1. Siemens Aktiengesellschaft (1 from 30,052 patents)
2. Christensen, Inc. (1 from 48 patents)
3. Wintershall Aktiengesellschaft (1 from 18 patents)
4. Deutag Deutsche Tiefbohr-ag (1 from 1 patent)
5. Preussag Ag Erdol Und Erdgas (1 from 1 patent)
2 patents:
1. 4862973 - Drilling derrick device
2. 4200159 - Cutter head, drill bit and similar drilling tools