Im- PROVEMENTS IN TRACTION ENGINES AND WHEELS, AND IN CARRIAGES TO BE DRAWN BY TRACTION ENGINES, WHICH IMPROVEMENTS IN WHEELS ARE APPLI- CABLE TO COMMON ROAD CARRIAGES GENERALLY
Year: 1861

page_text: PROVISIONAL SPECIFICATION left by John Marshall at the Office of
the Commissioners of Patents,. with his Petition, on the 23rd October
1861.
I, JOHN MARSHALL, of Great George Street, in the City of Westminster.
5 Civil Engineer, do hereby declare the nature of the said Invention for "Im-
PROVEMENTS IN TRACTION ENGINES AND WHEELS, AND IN CARRIAGES TO BE
DRAWN BY TRACTION ENGINES, WHICH IMPROVEMENTS IN WHEELS ARE APPLI-
CABLE TO COMMON ROAD CARRIAGES GENERALLY," to be as follows:-
My Invention in traction engines, consists in placing the driving pinion
O which gears
into the inside toothed rack of the driving wheels, either on a
line with, and forward or below, and forward of the axes of the driving wheels.
This pinion slides between horn plates or other suitable guides in the framing
in a vertical direction, to allow of the play of the springs, by which the weight
of the engine is supported when at work upon the driving pinion; the pinion is
5-connected with the engine by suitable wheels and pinions to produce the requisite
changes of speed. The axes of the driving wheels also slide in the framing, by
having the axle boxes sliding in horn plates or other suitable guides, curved with
a radius equal to the distance of the driving pinion first mentioned from the-
centre of the driving wheel. When the engine is standing still, the weight
o taken by the driving wheels is supported by the springs at their centre, but
so soon as the engine is put in motion, according to the power required to
move the engine and its load, so much of the weight of the engine is transferred
from the centre of the driving wheel to that point in the circumference where

page_text: the driving pinion gears into the toothed rack upon the driving wheel, and the
amount of weight thrown upon the pinion is taken off the centre of the driving
wheels, so that if the driving wheels were fixed the whole weight of the
engine would be transferred from the centre towards the circumference. By
this arrangement of the driving pinion, the weight is transferred from the
centre of the wheel or line of direct vertical pressure towards the circum-
ference to a distance equal to the horizontal distance between the centre
of the driving wheel and the driving pinion, by which the wheel is com-
pelled to roll forward or slip with a power equal to the weight of the engine
acting upon a lever whose length is equal to the horizontal distance between
the centre of the wheel and the pinion.
My improvements in carriages to be drawn by the traction engine are as
follows-I fit a toothed rack inside the felloe or periphery of the hind wheels,
or both fore and hind wheels, having a pinion gearing into and fitted in a
similar manner to the engine before described, and driven by a horizontal
shaft extending along the bottom of the carriage and connected to the engine
by suitable couplings and gearing.
My improvements in wheels for traction engines and other common road
carriages consist in placing within the rim or felloe of the wheel a raised rail,
the spokes being placed either within or without the centre of the felloe or
both. I divide the wheel into four quarters by lines drawn horizontally and
vertically through the centre. Within the wheel I place a frame with two arms;
this frame is keyed or bolted to the axle on the aftermost arm. I place a
grooved roller, bearing against and embracing the raised rail within the felloe
of the wheel at a point either upon or a little below where the horizontal line
separating the upper from the lower aftermost quarter cuts the felloe; on the
other arm I place another grooved roller bearing upon and embracing the
räised rail within the felloe at or near a point about the middle of the lower
foremost quarter. By thus constructing the wheel, a portion of the weight is
(by the forward pull in drawing the carriage) thrown in advance of the line of
direct pressure of the wheel upon the ground.