Average Co-Inventor Count = 1.33
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. Other (1 from 832,812 patents)
2. National Mine Service Company (1 from 29 patents)
2 patents:
1. 4639647 - Four quadrant control of series motors
2. 4633147 - Electric powered vehicle and method of propelling the same