Swami:
Derwent will correct (or delete) any clearly erroneous IPCs we can identify
before adding a new patent to the DWPI database. The largest number come
from US patents (up to 50+ each week) and, as Edlyn pointed out, many of
these are non-existent codes. We will change other IPCs which are clearly
unrelated to the patent, but hold back from altering IPCs which are simply
"dubious" (for example, those correct at the group level) - as Robert
commented, Derwent introduced Manual Codes to provide a more consistent
indexing system that was under our own control.
In addition to informing the Patent Offices of these IPC errors, lists of
current corrections to IPCs for US, WO (PCT) and EP patents are available on
the Derwent website . (Use the Site Search facility to look up "IPC" for a
full list of what is available). Previous lists have been consolidated into
a single searchable database available at:
http://www.derwent.com/find/frameset.html.
Currently Derwent does generate additional IPCs from each new member of a
patent family even when they differ only at subgroup level. This policy was
introduced in 1992 (Derwent week 199216) at the request of users.
The history of IPC availability in the DWPI file is as follows:
(i) IPCs are available for most basic patents (new inventions) from 1970,
but they are not available for unexamined Japanese applications published
before April 1975, or from Canadian documents published before 1974 (Derwent
weeks 197403). The maximum number of IPCs which could be recorded for each
record (patent family) was 6.
(ii) From 1974 (Derwent week 197403) IPCs have been added from equivalents
when they differed at the main group level or above from those of the basic
patent in the family.
(iii) From 1980 (Derwent week 198049) the maximum number of IPCs that were
recorded was raised to 12. If IPCs only differed at the subgroup level,
only one was entered.
(iv) From 1992, as detailed above, IPCs have been added from equivalents
even when they differed only at subgroup level, and there has been
essentially no limit to the number of IPCs which may be recorded.
Best regards,
Neil Larque
Manager
European Help Desk
====================================================================
Customer Services
Derwent Information, 14 Great Queen Street, London WC2B 5DF, UK
Tel: +44 171 344 2999
Fax: +44 171 344 2900
Email: custserv@derwent.co.uk
URL: http://www.derwent.com/
====================================================================
-----Original Message-----
From: Peter Steele [mailto:Peter.Steele@cursci.co.uk]
Sent: 07 January 2000 08:48
To: 'Robert Buntrock'; Edlyn Simmons-ES; piug-l@derwent.tecc.co.uk
Cc: subramaniyan_narayanaswami@sandwich.pfizer.com
Subject: RE: International Patent Classifications
Swami:
My recollection of Derwent's IPC policy in the 1980s was that once a
particular IPC Group was represented in the record for a family, subsequent
family members with different (and perhaps more helpful) Sub-Groups of that
same Group did not generate additional IPC entries. So only the first
Sub-Group to arrive was searchable. I hope I've explained that clearly -
maybe someone at Derwent will offer a definitive account of WPI treatment of
IPCs?
Regards
Peter Steele
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