Using Derwent Classification to improve your subject searching - Dialog Example
Search Tips - July 2000
This is a search for patents on antilock braking systems (ABS) for cars and other vehicles which illustrates how Derwent Classes can be used to overcome the problem of ambiguous search terms. We begin with a keyword search, which yields more than fifteen thousand records. This is an unexpectedly high number, so the next step is to display a few records in an inexpensive format to check what is being retrieved. Format 26 includes Dialog and Derwent accession numbers, Derwent title and image availability tag.
Begin searching in Derwent World Patent Index (Derwent WPI) (File 351):
? b 351
In this word search, "w" means that the search terms are adjacent to each other in the specific order.
? s abs or (antilock? or anti(w)lock?)(w)brak?
13494 ABS
2121 ANTILOCK?
159757 ANTI
280266 LOCK?
2622 ANTI(W)LOCK?
116103 BRAK?
2777 (ANTILOCK? OR ANTI(W)LOCK?)(W)BRAK?
S1 15627 ABS OR (ANTILOCK? OR ANTI(W)LOCK?)(W)BRAK?
Display a few records in an inexpensive format to check relevance:
[for more details on display formats see Useful
formats for Derwent WPI]
? t 1/26/1-2
1/26/1 DIALOG(R)File 351:DERWENT WPI (c) 2002 Derwent Info Ltd. All rts. reserv. 013204178 **Image available** WPI Acc No: 2000-376051/200032 Apparatus for applying light irradiation to an object causing thermal coagulation that results in tissue necrosis has a controller that receives output from photodiode and controls source of light radiation 1/26/2 DIALOG(R)File 351:DERWENT WPI (c) 2002 Derwent Info Ltd. All rts. reserv. 013204059 WPI Acc No: 2000-375932/200032 Thermoplastic resin composition, for e.g. computer housing, contains polystyrene acrylonitrile |
? t1/26/26-28
1/26/26 DIALOG(R)File 351:DERWENT WPI (c) 2002 Derwent Info Ltd. All rts. reserv. 013217277 **Image available** WPI Acc No: 2000-389151/200034 Vehicle braking system for controlling speed of electrohydraulic braking comprises accumulator and replenished by pumping additional working fluid 1/26/27 DIALOG(R)File 351:DERWENT WPI (c) 2002 Derwent Info Ltd. All rts. reserv. 013216707 **Image available** WPI Acc No: 2000-388581/200034 Fire resistant polycarbonate-ABS molding material for production of molded housings and other parts contains a special arylene polyphosphate compound with two different arylene groups 1/26/28 DIALOG(R)File 351:DERWENT WPI (c) 2002 Derwent Info Ltd. All rts. reserv. 013216626 **Image available** WPI Acc No: 2000-388500/200034 Differential rotary speed regulation of connectable frictional contact connection and coupling or brake in motor vehicle drive line using regulating circuit with desired speed difference |
Large numbers of irrelevant records are being retrieved. The problem is the search term "ABS", which must be included in the strategy. However, ABS can also be an abbreviation for acrylonitrile-butadiene-styrene polymer and an abbreviation for antibodies.
Our search could be refined by incorporating further keywords such as cars or vehicles, but this would probably be too restrictive. The best way to overcome the problem is to confine the search to Derwent Class Q18 - Vehicle Brake Control Systems.
? s s1 and dc=q18
15627 S1
31580 DC=Q18 (Brake control systems)
S2 3119 S1 AND DC=Q18
Displaying a few records in an inexpensive format:
[for more details on display formats see Useful
formats for DWPI]
? t 2/28/11-13
2/28/11 DIALOG(R)File 351:DERWENT WPI (c) 2002 Derwent Info Ltd. All rts. reserv. 013174022 **Image available** WPI Acc No: 2000-345895/200030 XRPX Acc No: N00-260167 Electrically operated pump for antilock brake system of vehicle, has spring which presses the reservoir to pass discharged fluid to pumping section Number of Countries: 001 Number of Patents: 001 Title Terms: ELECTRIC; OPERATE; PUMP; ANTILOCK; BRAKE; SYSTEM; VEHICLE; SPRING; PRESS; RESERVOIR; PASS; DISCHARGE; FLUID; PUMP; SECTION Derwent Class: Q18; Q56; X22 International Patent Class (Main): F04B-017/04 International Patent Class (Additional): B60T-008/40; F04B-009/00 File Segment: EPI; EngPI Manual Codes (EPI/S-X): X22-C02C1 2/28/12 DIALOG(R)File 351:DERWENT WPI (c) 2002 Derwent Info Ltd. All rts. reserv. 013172565 **Image available** WPI Acc No: 2000-344438/200030 XRPX Acc No: N00-259007 ABS actuator for antiskid brake system of motor vehicles, is positioned diagonally inside engine room so that front side of actuator faces center area of engine room Number of Countries: 001 Number of Patents: 001 Title Terms: ACTUATE; ANTISKID; BRAKE; SYSTEM; MOTOR; VEHICLE; POSITION; DIAGONAL; ENGINE; ROOM; SO; FRONT; SIDE; ACTUATE; FACE; AREA; ENGINE; ROOM Derwent Class: Q18; X22 International Patent Class (Main): B60T-008/34 International Patent Class (Additional): B60T-017/02; B60T-017/04 File Segment: EPI; EngPI Manual Codes (EPI/S-X): X22-C02C3 2/28/13 DIALOG(R)File 351:DERWENT WPI (c) 2002 Derwent Info Ltd. All rts. reserv. 013172564 **Image available** WPI Acc No: 2000-344437/200030 XRPX Acc No: N00-259006 Solenoid valve for brake hydraulic pressure adjustment device in antilock brake operating unit, has cyclic recesses into which binding element is inserted whose resistance is small as compared with the base Number of Countries: 001 Number of Patents: 001 Title Terms: SOLENOID; VALVE; BRAKE; HYDRAULIC; PRESSURE; ADJUST; DEVICE; ANTILOCK; BRAKE; OPERATE; UNIT; CYCLIC; RECESS; BIND; ELEMENT; INSERT; RESISTANCE; COMPARE; BASE Derwent Class: Q18; Q66; X22 International Patent Class (Main): B60T-008/34 International Patent Class (Additional): F16K-027/00; F16K-031/06 File Segment: EPI; EngPI Manual Codes (EPI/S-X): X22-C02C3 |
This is a good result - but can we do better? We can use RANK to find out which Derwent Classifications appear most frequently in this set of records:
? rank dc
Started processing RANK
...Ranking 500 of 3119 records
...Ranking 1000 of 3119 records
...Ranking 1500 of 3119 records
...Ranking 2000 of 3119 records
...Ranking 2500 of 3119 records
...Ranking 3000 of 3119 records
Completed Ranking 3119 records
DIALOG RANK Results
--------------------
RANK: S2/1-3119 Field: DC= File(s): 351
(Rank fields found in 3119 records -- 87 unique terms) Page 1 of 11
RANK No. Items Term
-------- ----- ----
1 3119 Q18
2 2446 X22
3 390 S02
4 369 Q13
5 144 T01
6 134 Q66
7 122 Q57
8 91 Q17
P = next page Pn = Jump to page n
P- = previous page M = More Options Exit = Leave RANK
To view records from RANK, enter VIEW followed by RANK number,
format, and item(s) to display, e.g., VIEW 2/9/ALL.
Enter desired option(s) or enter RANK number(s) to save terms.
? exit
RANK results will be erased; have you saved all the terms of interest?
(YES/NO)
? y
Exiting rank... (no terms were saved)
From the result of our analysis we can see that X22 (Automotive Electrics) comes in second place. We can therefore bring X22 into our search as well. As can be seen from answer set "S3", we have considerably improved our search result by using both Derwent Classifications.
? s s1 and dc=(q18 or x22)
15627 S1
31580 DC=Q18 (Brake control systems)
186924 DC=X22 (Automotive Electrics)
S3 4018 S1 AND DC=(Q18 OR X22)
? t 3/26/20-22
3/26/20 DIALOG(R)File 351:DERWENT WPI (c) 2002 Derwent Info Ltd. All rts. reserv. 013162535 **Image available** WPI Acc No: 2000-334408/200029 Protective structure for bearing unit of axle shaft of antilock braking system, has rubber packing interposed between sensor and interior of insertion hole of cover attached to edge of outer ring bearing 3/26/21 DIALOG(R)File 351:DERWENT WPI (c) 2002 Derwent Info Ltd. All rts. reserv. 013162185 **Image available** WPI Acc No: 2000-334058/200029 Solenoid valve mechanism for brake pressure control apparatus opens secondary valve if needle resists biassing force of primary spring and if primary valve is in closed state 3/26/22 DIALOG(R)File 351:DERWENT WPI (c) 2002 Derwent Info Ltd. All rts. reserv. 013150396 **Image available** WPI Acc No: 2000-322268/200028 Acceleration sensor for antilock brake system in motor vehicle detects quantity of light emitted by LED using phototransistor, based on which variation in area of opening is detected |
Analysing Derwent Classifications is also a useful way of identifying a company's key activities. We will be looking at this in further detail in a Search Tip later this year.
For further assistance please contact your local Derwent Help Desk.