Average Co-Inventor Count = 3.43
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. National Oilwell, Inc. (2 from 68 patents)
2 patents:
1. 7523694 - Cylinder liner preload system
2. 6923254 - Washpipe apparatus