Search the Insulator Patent Reference Library:

Build your search criteria. The patent must match all the values specified.
Select patent types: Utility   Design   Reissue
Patent number:
Date:
Year between: and
Patentee starting with:
City:
State:
Assigned To starting with:
Description containing:
Category:
Class:    Subclass:
Click Search when complete:
SELECT DISTINCT patent.*, YEAR(date) as year FROM patent LEFT JOIN category ON category.patent = patent.patent AND category.type = patent.type WHERE (category.class = '73') AND (category.subclass = '439') ORDER BY category ASC, date, patent, type

Total of 1 patents found where: Class is '73'; Subclass is '439';

View a patent by clicking on the patent number. You can sort by any of the columns by clicking on the column name.

T / S Patent Date Description Patentee Category Assigned To
 Manufacturing
U 1,822,458 September 8, 1931 Measuring Apparatus
Device to measure the density of clay slip
ROWLAND, Davidge H.
ROBERTSON, John C.
Manufacturing Locke Insulator Corp.

Total of 0.02 seconds