Walter Tenten wrote in 030903 MMDigest:

> The task of finding U.S. patent numbers, necessary for all patents
> issued prior to 1976, is sometimes a very tough one.

Having one patent number may be key to finding others.  Every U.S.
patent is available on the U.S. Patent & Trade Office web site,
http://www.uspto.gov/ , going all the way back to #1, but only those
most recently issued are run through an OCR program and so are
available for searching by text.

But once you have a patent in an area of interest, you can generally
find other similar patents by use of the reference numbers.  By
searching for the patent number above [1,427,336] , the results page
includes this notation:

  United States Patent 1,427,336 & Current U.S. Class:   83/221

The class numbers are the key to finding similar patents.  To find out
what the class number means go to the page linked from the main page
and click on the "Tools to Help in Searching by Patent Classification".
Enter the class 83 and subclass 221 and get the resulting class page
list.  This page includes all the subclasses in class 83 but should
home in on 221.  Click on 221 and you will be taken to a large page
with the subheading 221 and see this class of patents deals with
"Work-feed mechanism in nonfeed motion effects or initiates tool
actuation" so the patent you have most likely deals with machines that
have indexing mechanisms to move the work.  Roaming around in the class
definitions can get you to a closer match sometimes.

To view the patent numbers under this classification, go back to the
patent search page and enter the following in the search window:

  ccl/83/221

and set the search range to look back to 1790.

The screen you see will list all the patents in that class and subclass
ever issued.  There are 87 of them and this is typical.  Looking at
each is a tough job.  But consider that patents are issued serially and
only look for patents in the years you expect to find information for
your use.

For instance, these are the first patent numbers issued in each of the
following years:

1890   418,665
1900 640,167
1910 945,010
1920 1,326,899
1930 1,742,424

If we look from 1910 to 1920 there are fewer patents to look at:

60 1,710,001
61 1,633,718
62 1,615,020
63 1,534,687
64 1,527,064
65 1,499,537
66 1,441,976
67 1,427,336
68 1,379,420
69 1,241,246
70 1,204,214
71 1,175,986
72 1,160,885
73 1,109,966
74 1,100,033
75 1,078,350
76 1,052,331
77 1,022,888
78   980,028

All of those patents are linked directly so you can view them without
going through another search.  Looking at three of those arbitrarily,
I find one is for a cork cutting machine, one is for a veneer cutter
and the third is for a (Morse code paper punch) signal recorder.  We
can also home in on the patents nearest the one we know to see if there
were contemporary patents.  Doing this for the immediately adjacent
patents I find a ticket issuing machine and a leather cutting machine.
So it goes.

To view the patents in their original image format, it is necessary to
download a plug-in.  You can find information on the help link when you
try to view the pages.  The download is fast and what you will see will
impress you.  You can save the pages and view them offline or print
them to suit.

There are various ways of winding through the class and subclass
designations to home in on one that suits your search.  They are time
consuming but great fun.  One of the best is the index.  There I found
under "Music, Recording Movement of Keys" 84/461 and additional
sections 234/49 & 234/109.

Sorry for the long post.  In truth, it could have been much longer.
It's a long process, but you will learn a lot about early American
machinery.  If somebody knows of a good web page describing how to
do this, it would be good to post it.

Don Shenbarger