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. Japanese National Railways (1 from 50 patents)
2. Oiles Industry Co., Ltd. (1 from 27 patents)
3. Oiles Co., Ltd. (1 from 1 patent)
2 patents:
1. 4648224 - Tendon for prestressed concrete
2. 4320548 - Method of erecting a bridge girder