Average Co-Inventor Count = 6.20
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. (4 from 4 patents)
3. Railway Technical Research Institute (2 from 65 patents)
4. Sumitomo Metal Technology Inc. (1 from 1 patent)
5. Sumikin Osaka Plant Engineering Co., Ltd. (1 from 1 patent)
6. Hakusan Seissaku-sho Co., Ltd. (1 from 1 patent)
7. Kyushu Tetsudo Kiki Seizo Co., Ltd. (1 from 1 patent)
6 patents:
1. 5303514 - Rail grinding apparatus
2. 4762263 - Small-sized gas pressure welding machine for rails with two separate
3. 4576324 - Gas pressure welding machine
4. 4556164 - Method of field welding head-hardened rails
5. 4416158 - Punching-shearing method for inspecting quality of butt welded joint
6. 4272003 - Butt welding and burr shearing machine for reinforce steel