DIFF Subgroup
B28B 21/18 using expansible or retractable mould or core elements
Introduced: September 1968
Full Title
Methods or machines specially adapted for the production of tubular articles > by casting into moulds > using compacting means > using expansible or retractable mould or core elements
IPC and CPC are identically structured here. All 1 subcodes exist in both systems.
1 shared codes have differing titles between IPC and CPC.
Child Classifications
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- B28B 21/20 using inflatable cores, e.g. having a frame inside the inflatable part of the core (connection of valves to inflatable elastic bodies B60C29/00) +1 CPC IPC+CPC Available in IPC and CPC
Top Applicants
Top Applicants (IPC)
Class B28,2013–2023, worldwide · Source: EPO PATSTAT
- MITSUBOSHI DIAMOND INDUSTRIAL COMPANY 868
- QINGDAO GAOCE TECHNOLOGY COMPANY 678
- DISCO CORPORATION JP 500
- ZHOU ZHAODI 500
- MITSUBOSHI DIAMOND INDUSTRIAL COMPANY JP 456
- HILTI LI 455
- CORNING US 407
- UNITED STATES GYPSUM COMPANY US 375
- ZHENGZHOU YUAN DONG REFRACTORIES COMPANY 370
- HUNAN SANY KUAIERJU RESIDENTIAL INDUSTRY COMPANY 351
Top Applicants (CPC)
Class B28,2013–2023, worldwide · Source: EPO PATSTAT
- DISCO CORPORATION JP 1,471
- HILTI LI 575
- CORNING US 544
- MITSUBOSHI DIAMOND INDUSTRIAL COMPANY JP 518
- UNITED STATES GYPSUM COMPANY US 485
- DISCO ABRASIVE SYSTEM 459
- GE (GENERAL ELECTRIC COMPANY) US 454
- MITSUBOSHI DIAMOND INDUSTRIAL COMPANY 439
- DISCO CORPORATION 403
- NGK INSULATORS JP 308