IMPROVEMENTS IN PORTABLE AND TRACTION ENGINES
Year: 1875

page_text: LETTERS PATENT to John Mc Laren, of Ravensthorpe, Normanton, in
the County of York, for the Invention of “ IMPROVEMENTS IN PORTABLE
AND TRACTION ENGINES."
Sealed the 6th December 1875, and dated the 7th June 1875.
PROVISIONAL SPECIFICATION left by the said John Mc Laren at the
Office of the Commissioners of Patents, with his Petition, on the
7th June 1875.
I, JOHN MCLAREN, of Ravensthorpe, Normanton, in the County of
York, do hereby declare the nature of the said Invention for "IM-
PROVEMENTS IN PORTABLE AND TRACTION ENGINES," to be as follows:-
This Invention has for its object improvements in portable and
traction engines.
In the construction of portable and traction engines I make the
boiler of the ordinary locomotive type, and on the top of the fire-box I
build a strong box frame; its sides are formed of plates rivetted to the
sides of the fire-box; its outer or hinder end is a stiff flanged plate of

page_text: cast iron passing over the crown of the fire-box; and its inner or front
end is a lighter plate of wrought iron. To stiffen this box frame I brace
the front and back plates together with wrought-iron bolts and distance
pieces. The crank shaft of the engine passes through the sides of the
box frame, and the front end of the box has openings in it for the
passage of the connecting and eccentric rods.
The cylinder of the engine is mounted so that it is free to slide longi-
tudinally on the top of the boiler, and it is connected with the front of
the box frame by two side plates or bars. The motion bars or guides
are attached at one end to a transverse plate bolted to the side plates or
bars, and at the other end to the cylinder cover. One of the side plates
or bars also carries a portion of the reversing gear.
The boiler is provided with a steam dome, from which the steam is
conducted to the cylinder by a bent pipe of copper. The steam
regulator is mounted on the cylinder; and there is also a steam cock
close to the connection with the steam dome. This is provided in
order that every part of the engine may be accessible when steam is up.
The crank shaft has upon it a belt pulley, also serving as a fly whecl; it
also carries a pinion which can slide upon it with groove and feather.
The pinion gears with an intermediate wheel on an axis which is carried
by the side plates of the box frame already described. The same axis
has a pinion upon it which gears with a toothed wheel upon the axle of
the main or driving wheels. The main axle is situated immediately
behind the fire-box.
The locking motion for the leading wheels is thus arranged:-A
bridge plate is fixed beneath the barrel of the boiler; the under side of
the bridge plate is flat, and it rests upon a cast-iron block. The two
parts are secured by a pin and cotter, but they are free to turn inde-
pendently. The block has two jaws on its under side, and between
them the axle of the fore wheels is received. A pin passes through the
axle and through the jaws, and the axle is free to rock about the pin
to allow the wheels to accomodate themselves to irregularities of the
land or road.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said John M Laren in the Great Seal Patent Office
on the 7th December 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
McLAREN, of Ravensthorpe, Normanton, in the County of York, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Seventh day of June, in the year
of our Lord One thousand eight hundred and seventy-five, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said John Mc Laren, Her
special license that I, the said John Mc Laren, my executors, admini-
strators, and assigns, or such others as I, the said John McLaren, my
executors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN PORTABLE AND TRACTION ENGINES," upon the condition
(amongst others) that I, the said John M° Laren, my executors or
administrators, by an instrument in writing under my, or their, or one
of their hands and seals, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said John Mc Laren, do hereby declare
the nature of the said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement thereof, that is to say :-
This Invention has for its object improvements in portable and
traction engines.
In the construction of portable and traction engines I make the boiler
of the ordinary locomotive type, and on the top of the fire-box I build
a strong box frame. Its sides are formed of plates rivetted to the sides

page_text: of the fire-box; its outer or hinder end is a stiff flanged plate of cast
iron passing over the crown of the fire-box, and its inner or front end
is a lighter plate of wrought iron. To stiffen this box frame I brace
the front and back plates together with wrought-iron bolts and distance
pieces. The crank shaft of the engine passes through the sides of the
box frame, and the front end of the box has openings in it for the
passage of the connecting and eccentric rods.
.
The cylinder of the engine is mounted so that it is free to slide longi-
tudinally on the top of the boiler, and it is connected with the front of
the box frame by two side plates or bars. The motion bars or guides 1
are attached at one end to a transverse plate bolted to the side plates or
bars, and at the other end to the cylinder cover.
One of the side plates
or bars also carries a portion of the reversing gear.
The boiler is provided with a steam dome, from which the steam is
conducted to the cylinder by a bent pipe of copper. The steam 1
regulator is mounted on the cylinder, and there is also a steam cock
close to the connection with the steam dome. This is provided in order
that every part of the engine may be accessible when steam is up. The
crank shaft has upon it a belt pulley, also serving as a fly wheel; it
also carries a pinion which can slide upon it with groove and feather. 2
The pinion gears with an intermediate wheel on an axis which is
carried by the side plates of the box frame already described. The
same axis has a pinion upon it which gears with a toothed wheel upon
the axle of the main or driving wheels. The main axle is situate
immediately behind the fire-box.
The locking motion for the leading wheels is thus arranged:-A
bridge plate is fixed beneath the barrel of the boiler; the under side of
the bridge plate is flat, and it rests upon a cast-iron block. The two
parts are secured by a pin and cotter, but they are free to turn inde-
pendently. The block has two jaws on its under side, and between a
them the axle of the fore wheels is received. A pin passes through the
axle and through the jaws, and the axle is free to rock about the pin to
allow the wheels to accommodate themselves to irregularites of the land
or road.

page_text: Figure 1 is an elevation partly in section of the engine; Figure 2 is
a plan view of the same; Figure 3 shews a section on the line 1, 2,
Figure 1.
Figure 4 shews an elevation of fire-box end of engine.
A is the boiler of the ordinary locomotive type; B, B, are plates
carried up from the sides of the fire-box; C is a stiff flanged plate of
cast-iron passing over the crown of the fire-box, and fixed at its ends to
the rear ends of the plates B; D is a wrought-iron plate similarly
passed over the fire-box and fixed at its ends to the forward end of the
plates D; E, E, are distance pieces and tie rods to brace together the
front and back plates C and D.
One tie and distance piece is shewn in Figure 1 passing below the
crank shaft, and in the enlarged section, Figure 5, I have shown two
ties and distance pieces, one below and one above the crank shaft. F is
the cylinder connected by side girders G to the plate D. The cylinder
rests upon a saddle H fixed to the shell of the boiler.
Figure 3 shews the way in which the cylinder is attached to the saddle
to allow the boiler to freely expand and contract whilst the cylinder is
held rigidly by the side girders G; I is the steam dome from which
steam is conducted to the valve chest of the cylinder by a bent
pipe J of copper.
As before stated a cock is provided close to the connection with the
steam dome by which steam may be shut off from the cylinder; K is
the crank shaft carrying a fly wheel which serves as a belt pulley, and
also a pinion L for transmitting motion, as shown at Figures 1, 2,
and 4, to the axle of the main or driving wheels, which axle is imme-
diately behind the fire-box.
My improved locking motion for the leading wheels is shewn at
Figures 1 and 6. M is a bridge plate fixed beneath the barrel of the
boiler; the under side of this plate is flat and rests upon the cast-iron
block N which is secured to it by a pin O; N¹, N¹, áre jaws on the
under side of the block N; P is the axle passing between these jaws;
and Q a pin passed through the jaws and through the axle. The axle
being free to rock upon this pin the wheels can accommodate themselves
to irregularities of the road or land.
Having thus described the nature of my Invention, and the manner
of performing the same, I would have it understood that I claim,—

page_text: First. The combined arrangement of traction engine, substantially as
herein-before described.
Second. The construction of portable and traction engines with a
box frame composed of plates B, C, and D, above the fire-box, and with
side girders G and steam cylinder free to move longitudinally and t
supplied with steam from the steam chest by a bent flexible pipe, sub-
stantially as described.
Third. The improved construction of locking motion for the front
wheels of traction and portable engines, substantially as described.
In witness whereof, I, the said John M Laren, have hereunto
set my hand and seal, this Fourth day of December, in the
year of our Lord One thousand eight hundred and seventy-
five.