Average Co-Inventor Count = 6.08
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 (4 from 50 patents)
2. Hakusan Seisakusho Co., Ltd. (3 from 4 patents)
3. Hakusan Seissaku-sho Co., Ltd. (1 from 1 patent)
4. Kyushu Tetsudo Kiki Seizo Co., Ltd. (1 from 1 patent)
4 patents:
1. 4576324 - Gas pressure welding machine
2. 4556164 - Method of field welding head-hardened rails
3. 4416158 - Punching-shearing method for inspecting quality of butt welded joint
4. 4272003 - Butt welding and burr shearing machine for reinforce steel