James Barker, PE, working in evenings, created a spreadsheet of patents from 1918 and earlier relating to bridges because the work and ideas were interesting to him. The database is copyrighted by Jim in the year 2003. He has furnished it to a few of his friends for their use, but it is not to be furnished to anyone else without written approval from author. Mr. Barker had to do his own checking. This included cross checking against a printed list of bridge patents in a library book, and viewing each patent a second time to check back against the database entry. However, some mistakes and omissions surely exist. If errors are found, please report them to the author. Click here to learn more about Jim Barker's effort.
The Jim Barker Bridge Patent Database represents the complete spreadsheet produced by Jim Barker, converted into a searchable online database with expansions and enhancements by Nathan Holth, bridge historian. The expansions include additional comments for selected patents, additional classifications by bridge type. In a much less complete (and ongoing) effort, Nathan Holth has chosen to expand the database by adding selected bridge-related patents relating to movable bridges and bridge-related patents dating to after 1918, as these areas were outside of Mr. Barker's primary focus.
Entering any of the following in the General Search box will help search for patents of a particular subject. Similarly, if you choose to Order Search Results By "Jim Barker Description" the results will for the most part be sorted by the following terms that usually preface Jim Barker's comments.
aerial tram
arch
beam
bowstring
cable-stayed
caisson
cantilever
column
conc. or concrete
conn (i.e., connections)
constr.
method or constr.
culvert
deck
elev. RR
expansion bearings
eyebar
floating
fnd. (i.e., foundations)
girder
guardrail
movable
pier
pontoon
susp br.
tied arch
transporter br.
trestle
truss
weather protection
Introduction
This database starts with the oldest patents on the US Patent Office website,
and includes every bridge patent (that Mr. Barker found) to the year 1918, which
is the end of the First World War and a turning point of sorts in technologic
eras.
A fire burned through the patent office around 1837. Although the
patents were lost, lists and summaries held elsewhere survived. Thus, it is
known that there were earlier bridge patents. An article by Francis Griggs, Jr.
titled It's a Pratt! It's a Howe! No, It's a Whipple Truss in Civil
Engineering Practice, Spring/Summer 1995 lists 24 bridge patents issued
earlier than 1830. Twenty of them are not found in this database.
The
realm of bridge patents has ragged, gray boundaries. The dividing lines are less
sharp than one might think. For instance, the dividing line between arches for
bridges and arches for buildings is difficult to pin down. Sometimes it depends
only on what purpose the inventor claims for the structure. Also, the dividing
line between suspension bridges and aerial tramways can get fuzzy. Some
bridge-like aerial tram patents are included, while others, somehow less
bridge-like, have been left out. Yet again, the dividing line between
construction techniques specific to bridges, and techniques that have general
use, is difficult to discern. In Class 52, there is a whole sub-classification
for elevated railways. Some of these patents deal more with the system and less
with the bridges.
Elevated Railway patents are particularly borderline.
Many pertain to cable-supported monorail systems that, if they carry cable cars,
might be considered bridge systems, but can also look a lot like cable-supported
trams. Sometimes the patents pertain more to equipment and dismiss the structure
as the "means of supporting car" or "iron straps riveted together". The
people-movers are generally included, and the equipment patents are not.
The patent office classifications are a very good start, but are not perfect.
Many interesting bridge patents lie outside Class 14, Bridges. And an occasional
coffee grinder sneaks into Class 14. Class 52, Static Structures, and Class 104,
Railways are especially fertile for rogue bridge patents.
The database
includes all parts of class 14 except movable bridges. There were large numbers
of machinery-oriented patents there, and Mr. Barker was overwhelmed. However, he
did include a few transporter bridge patents that he ran across outside of Class
14, and he did include a few moveable bridge patents by famous engineers that he
found (not wishing to do to J.B. Strauss what Strauss tried to do to Charles
Ellis). Generally, these were patents that Mr. Barker ran across outside the
confines of Class 14.
Mr. Barker started by viewing each of the
non-moving patents in Class 14 and noting the other classifications that were
cross-listed. He then summarized the cross-listings and searched the other
categories that had two or more "bridge" patents or were the prime
classification (see below) for one or more bridge patent. The searched
classifications are listed at the end of this paper.
Classifications
Four columns for classifications appear in the database. These give the US
Patent Office's classification and subclass for each patent. If a single number
appears (e.g., "9" or "73.5") that number is a sub classification in the overall
Bridge class = 14. If, however, a dual number appears (e.g., "104/125"), that
patent "listing" appears in the noted class and subclass (class 104 = railways,
and subclass 125 = towers and piers for elevated RR).
The "Prime" entry
of the four gives the patent's primary classification.
The other three give
secondary classifications that have been assigned by the patent office.
A few
patents have more than four, and their last one(s) were merely left off.
The Classifications and Subclassifications searched are listed below. It is
believed that all bridge patents in these classifications in the Patent Office
website were included in the database. However, there were many judgment calls,
especially regarding construction apparatus and techniques.
Class 14,
Bridges:
All subclassifications except the movable bridge subclasses, 31
through 72.5
Class 52, Static structures (e.g., buildings):
Subclasses
2.19, 23, 86, 87, 88, 89, 174, 223.8, 316, 334, 376, 506.06, 639, 640, 644,
648.1, 651.07, 690, 731.2, 737.1, 737.2, 737.3, 741.1, and 750
Class 59,
Chain, staple, and horseshoe making: Subclasses 78 and 84
Class 104,
Railways:
Subclasses 46, 47, 49, 90, 94, 115, 117, 123, 124, 125, 180, and
201
Class 174, Electricity: Subclass 43
Class 198, Conveyors:
Subclass 834
Class 212, Traversing hoists: Subclasses 177 and 312
Class 238, Railways: surface track: Subclasses 2 and 11
Class 249, Static
molds: Subclasses 1, 7, 23, and 24
Class 403, Joints and connections:
Subclasses 45, 292, and 341
Class 404, Road structure, process, or
apparatus: Subclass 1
Class 405, Hydraulic and earth engineering:
Subclasses 13, 150.1, 195.1, 211, 213, 224, 228, 229, 231, 233, 251, 273, and
284
Class 411, Fasteners: Subclass 63
Location of Residence
The Post Office's two-letter state abbreviations are used. Some patents came
from Territories before states were formed. These are noted "Terr". The few "Ind'n Terr" entries mean the author resided in Indian Territory, showing that
technological striving even crept into the Wild West. Germany = Ger, France =
Fra, England = Engl, etc..
In some instances the county name is given in
the patent and added in the appropriate column. This was done mostly for small
towns where the county name might identify location better. But one hardly needs
to be told that Chicago lies in Cook County.
In a few instances, the
author's residence is not identified in the patent, or is only partly noted.
Description of Patent
Mr. Barker looked at each patent. He examined the drawings, and scanned the
text. He generally paused a few moments on the initial statement of purpose
(usually the second, third, or forth paragraph), and moved on to the claims at
the end. He then tried to summarize the patent in these few words. A thankless
task, but better than not doing it.
A few descriptions turned out
slightly acerbic. Mr. Barker considered rewording them to more circumspect and
professional phrasing, and decided not to, and that this was some recompense for
having done the work without funding or support.
Some patents had over
thirty different claims, so the database's 15-words-or-less description comes
with no guarantees. Descriptions have been often started with a key word such as
"truss" or "arch bridge" or "susp br." or "constr. method" so that a sort on
this field will yield useful results. But this approach could not be followed
perfectly. Sorting on the description field will yield some agglomeration of
similar patents, but will leave out many other relevant ones.