IMPROVEMENTS IN TRACTION ENGINES
Year: 1873

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the
Office of the Commissioners of Patents, with his Petition, on
the 20th August 1873.-A communication from abroad by Robert
Crouch Parvin, of Farmington, and Nathan Overman, of Canton,
both of Illinois, United States of America.
I, WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co.,
Patent Agents, Southampton Buildings, London, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN TRACTION ENGINES," a
communication, to be as follows:-
The traction engine embodying these improvements is provided with
a bed or frame mounted upon an endless carrier or traction band
by which propulsion is accomplished, also with a boiler and the usual
appurtenances for generating steam and applying the same to the
object in view, and with a pair of forward wheels which aid in
supporting the boiler, and by which the engine is guided over the
field.
"
The endless carrier or traction band consists of a peculiarly formed
chain hung beneath the bed or main frame of the engine upon a pair of
cam wheels to which a rotary motion is communicated by suitable

page_text: means from the steam cylinders. This chain is provided with a series of
transverse bars or feet which as the chain is moved are laid upon and
taken from the ground in succession, thereby moving the engine over
the ground.
The transverse bars or feet of the carrier are provided at each of their
ends with rollers which rest against and move upon rails secured to the
bed or frame in such manner that the said rollers travel over these rails
above and below, the said rails also afford bearings for the axles of the
cam wheels over which the endless chain passes. No more than two
of the carrier feet need rest upon the ground at a time, and the whole 1
series should be so arranged that just as one foot is about to leave the
ground another foot will assume a position to exert tractional power.
By this arrangement not only is the requisite traction obtained but the
carrier is made so short that the engine may be readily turned or
guided.
In order to enable the feet to assume their proper position upon the
ground and leave it without difficulty, they are made convex or rounded
on their outer surfaces or faces.
1
The wheels located at the front part of the engine to serve as guides
should possess a large amount of traction power or "bite," and to this 2
end should bear considerable weight. For this and other reasons the
boiler is placed between the front wheels and main frame or bed of the
engine in such manner that the weight of the said boiler will fall in a
great measure upon the said guiding wheels. Were the frame beneath
which the traction band is hung to extend forward to and be connected a
directly with the front wheels without the intervention of a joint,
whenever the said wheels met and mounted an obstruction the carrier
feet would be partly raised from the ground, thus diminishing the
traction surface covered and seriously interfering with the progress of
the engine. To avoid this difficulty a joint is made between the front a
and rear sections of the engine or between the boiler and main frame, so
that the carrier may adapt itself to the surface of the ground whether it
be in the same plane with that upon which the wheels rest or not. By
this means neither the front or rear section of the engine is affected
by any ordinary uneveness of ground encountered by the other.
The forward wheels are hung upon a pivoted axle so connected with
the boiler, to which it is attached, that the said wheels may be

page_text: drawn alternately backward and forward as needed for the guidance of
the engine, and the attachment of the axle to its bearing is such that a
variation of the plane of either wheel will not affect or disturb the plane
of the boiler. When ploughs or other implements are to be drawn they
are attached to the rear end of the engine or carrier frame.
When ploughs are drawn a gang of them is used, and these are
arranged for adjustment to different depths of soil and otherwise.