IMPROVEMENTS IN LOCOMOTIVE ENGINES, PARTS OF WHICH MAY BE USED IN OMURE STEAM ENGINES
Year: 1871

page_text: LETTERS PATENT to Thomas Weatherburn Dodds, of Stoke-upon-
Trent, in the County of Stafford, Engineer, for the Invention of
"IMPROVEMENTS IN LOCOMOTIVE ENGINES, PARTS OF WHICH MAY BE USED IN
OMURE STEAM ENGINES."
Sealed the 29th August 1871, and dated the 9th March 1871.
PROVISIONAL SPECIFICATION left by the said Thomas Weatherburn
Dodds at the Office of the Commissioners of Patents, with his
Petition, on the 9th March 1871.
I, THOMAS WEATHERBURN DODDS, of Stoke-upon-Trent, in the
County of Stafford, Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN LOCOMOTIVE ENGINES, PARTS OF WHICH MAY
BE USED IN OTHER STEAM ENGINES," to be as follows:-
My Invention relates, in the first place, to slide valve gear, and consists
of two distinct expansive motions with one excentric and two straps
thereon actuated by one pair of wedges. In the one case one excentric
rod is connected directly to the valve spindle and the other transmits
motion to the valve spindle of the second cylinder through a bell crank
carried on a cross shaft, which shaft is carried upon levers forming a

page_text: parallel motion with the axle. In the other case the excentric rods
work two bell cranks at right angles, the arrangements being otherwise
the same as in the former caso.
My Invention consists, in the second place, in forming the division
plate in the valve chest between two ordinary slide valves in two parts,
with flanges fitting one inside the other, a packing ring being inserted
between the said flanges and a spring between the inner sides of the said
two parts of the plate. By this arrangement the two outer sides of the
plate are capable of adjustment to the back of the valves, which are also
thereby relieved from pressure.
My Invention consists, in the third place, in forming the upper or
both brasses in axle boxes with a convex side fitting into a corre-
sponding concavity in the box, the curvature of which is a segment of
a circle struck from the centre of the axle bearing, the centre parts of
the brasses being also slightly convex, so as to give a limited amount ]
of play and accommodate the brass or brasses to the movement of the
axle, thereby allowing of the axle being always in contact with the
bearing.
And my Invention consists, in the last place, in fastening the tyres on
locomotivo and other railway wheels by means of an inclined wedge- 2
shaped ring inserted in a recess, the half of which is formed in the
tyre and the other half in the part of the wheel to which the tyre is
fixed. This mode of fastening is in substitution for the bolts ordinarily
employed for the purpose.
The abovo-described parts relating to slido valve expansive motions 2
may also be used in marine or stationary engines, in which cases the
levers carrying the cross shaft of the bell crank would be dispensed
with. In marine or stationary engines the crank shafts are carried in
fixed bearings, therefore the cross shaft of the bell cranks will in such
case be carried on fixed bearings, the said motion is applicable to all 3
double engines (the one excentric working both engines) which have an
expansive or reversing motion.
The above-described arrangement for relieving the backs of slide
valves from pressure may also be applied to marino and stationary

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Weatherburn Dodds in the Great Seal
Patent Office on the 8th September 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
WEATHERBURN DODDS, of Stoke-upon-Trent, in the County of Stafford,
Engineer, send grecting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Ninth day of March, in the year of
our Lord One thousand eight hundred and seventy-one, in the thirty-
fourth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Thomas Weatherburn Dodds, Her special
licence, that I, the said Thomas Weatherburn Dodds, my executors,
administrators, and assigns, or such others as I, the said Thomas
Weatherburn Dodds, 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 LOCOMOTIVE ENGINES, PARTS OF WHICH MAY BE
USED IN OTHER STEAM ENGINES," upon the condition (amongst others) that
I, the said Thomas Weatherburn Dodds, 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 Thomas Weatherburn Dodds, do
hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement, reference being had to the
Drawings hereunto annexed and to the letters and figures marked
thereon (that is to say)
My Invention of "Improvements in Locomotive Engines, parts of
which may be used in other Steam Engines," relates, in the first place,
to slide valve gear, and consists of two distinct expansive motions with
one excentric and two straps thereon actuated by one pair of wedges.
In the one case one excentric rod is connected directly to the valve

page_text: spindle and the other transmits motion to the valve spindle of the
second cylinder through a bell crank carried on a cross shaft, which shaft
is carried upon levers forming a parallel motion with the axle. In the
other ense the excentric rods work two bell cranks at right angles, the
arrangements being otherwise the same as in the former casc.
My Invention consists, in the second place, in forming the division
plate in the valve chest between two ordinary slide valves with two rings
having flanges fitting one inside the other, a packing ring being inserted
between the said flanges, and a spring between the inner sides of the
said two parts of the plate. By this arrangement the two rings or outer
sides of the plate are capable of adjustment to the back of the valves,
which are also thereby relieved from pressure while working against tho
division plate.
My Invention consists, in the third place, in forming the upper or both
brasses in axle boxes with a convex side fitting into a corresponding
concavity in the box, the curvature of which is a segment of a circle
struck from the centre of the axle bearing, the centre parts of the brasses
being also slightly convex or so as to give a limited amount of play and
accommodate the brass or brasses to the movements of the axle, thereby
allowing of the axle being always in contact with the whole length of
the bearing.
And my Invention consists, in the last place, in fastening the tyres
on locomotive and other railway wheels by means of an inclined wedge-
shaped ring inserted in a recess, the half of which is formed in the tyre
and the other half in the part of the wheel to which the tyre is fixed.
This mode of fastening is in substitution for the bolts ordinarily employed
for the purpose.
The above-described parts relating to slide valve expansive motions.
may also be used in marine or stationary engines, in which cases the
levers carrying the cross shaft of the bell crank would be dispensed
with. In marine or stationary engines the crank shafts are carried in
fixed bearings, therefore the cross shaft of the bell cranks will in such
case be carried on fixed bearings. The said motion is applicable to all
double engines working at right angles (the one excentric working both
engines) which have an expansive or reversing motion.
The above-described arrangement for relieving the backs of slide
valves from pressure may also be applied to marine and stationary
engines.

page_text: Having thus stated the nature of the said Invention, I will procced
to describe more particularly in what manner the same is to be per-
formed, by the aid of the accompanying Drawings, in which are repre-
sented the parts of locomotive engines hercin-before referred to.
sented the parts of locomotive engines hercin-before referred to.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 is a vertical section of the first expansive motion referred to,
the section being taken through the crank shaft with the left-hand crank
removed; Fig. 2 is a plan or horizontal view of the same shewing the
excentric in mid-gear.
A is the right-hand excentric strap proceding direct from the crank
shaft to the right-hand valve spindle; B, B, is the bell crank and shaft
transmitting the motion from the left-hand excentric strap to the left-
hand valve spindle, the left-hand excentric strap being coupled to one
end of the bell crank and at right angles to the other excentric strap,
or instead of using two excentric straps one strap may be employed, the
connection with the bell crank being formed by a link; C, C, are the
side levers held in position to the frame by brackets at each end and
supporting the bell crank and shaft B, B. The upper side lever is
connected to the axle box by a pillar secured at one end to the axle box
and at the other end coupled to the side lever by a short link. By con-
necting the side levers in this manner the centres are so arranged as to
give to the bell crank a vertical motion parallel to the crank axle. The
side levers with the bell cranks may be placed below the crank axle if
necessary.
Figures 3 and 4 are a vertical section and plan of the second expansive
motion referred to, shewing the excentric in mid-gear as in the former
case. A, A, are the counter shafts and bell, cranks in position as shewn
carried on side levers G at each end; B, B, are the excentric rods and
straps working at right angles with each other, each being at an angle
of forty-five degrees with the centre line of the cylinder. The right-
land excentric rod is coupled to the upper bell crank and the left-hand
excentric rod to the lower one, the motion then being transmitted direct
from the other ends of the bell cranks to the respective valve spindles; C
is the clutch box; D, D, are the wedges; E is the excentric; the position
of the right-hand crank is shown at R; G, G, are the side levers (onc
on each side of the engine) which are secured at one end to the frame

page_text: and at the other end to the axle box, and support the counter shaft at
each end.
The mode of reversing with the excentric guides, wedges, and clutch box
(with other ordinary parts) applicable to both motions is as follows:—
The excentric guides are solid with the crank axlo or fixed thereto and
retain the excentric in its position on the crank shaft admitting of its
motion in one direction only, that is to say, when actuated by tho
wedges D, D, in a direction transverse to the centre line of the axle.
The wedges D, D, are or may be solid with the clutch box C, which is
acted upon for reversing the motion in the usual manner from the foot
plate of the engine by means of a quadrant and lever coupled by a
reversing rod and lever, which moves the clutch box (by a trunnion
ring) laterally along the crank shaft. The distance from the centro
of the shaft to the centre of the excentric in mid-gear is equal to the
sum of the lap and lead required in the valve, and the centre of the
executric is caused by the action of the wedges to traverse an equal
distance on each side of its position in mid-gear, the diameter of the
circle passing through the two extreme points of its traverse being equal
to the travel of the valve, the lead of the valve being always a constant
quantity.
Fig. 5 is a section shewing an application to a division plate in the
valve chest between two ordinary slide valves of two rings, of which A
is the outer ring, B an internal cross for the support or abuttal of the
spring C, the ends of which press against the flanges on the interior of
the inner ring D, in which is formed a groove containing a brass
packing ring; E is a cast-iron bracket for supporting the stationary
rings A and D in position; F, F, are the slide valves with steam ports
in contact. The outer ring A fits loosely in the bracket E, and the
rings A. and D in the division plate are kept in contact with the backs
of the valve F, F, by means of thes spring C aided by the pressure of
the steam on the flange of the inner ring D and the edge of the outer
ring A. Arrangements for supporting the rings in position may be
adapted to circumstances. Fig. 6 is a plan or horizontal view of the
parts with the left-hand valvo removed. By the foregoing arrange-
ment the rings in the division plate are kept in required contact with
the backs of the valves as the latter work against the division plate.
Figures 7 and 8 are vertical sections of an axle box as applied to
locomotives, and Fig. 9 is a horizontal section of the same. A, Fig. 8,

page_text: shews the section through the centre of the brass, which is flattened on
the sides, the top being turned to a radius from the centre of the journal
to the outside, the top of the box being bored out with the same radius
to receive it. A clearance B, B, is cut in the lower brass or keep, by
means of which the brass is allowed to oscillate in the direction of
the arc, thereby always keeping the whole length of the bearing in
close contact with the axle, which is constantly being diverted from
its horizontal position by the inequalities of the way. Instead of
forming a clearance in the lower brass or keep, this brass may be
mado to correspond exactly with the top one, and made to oscillate in
the keep.
Figures 10 and 11 are sections, and Fig. 12 a half section of an axle
box as applied to carriages and waggons.
In this case a cast-iron
oscillating back is used with a brass of ordinary form. The box is in
other respects the same as for a locomotive.
Fig. 13 is a section of a portion of a railway wheel shewing the
tyre A, the wheel centre B, and a wedge-shaped ring C for uniting the
tyre to the wheel. This ring may be either of hard material formed
in segments and caulked after being inserted, or it may be run in with
soft metal and caulked.
Fig. 14 is a similar view of corresponding portions of a wheel, the
wheel centre and tyre being dovetailed together, thereby giving the
power of holding the tyre to the wheel in case of a fractured tyre.
The same conditions apply to the fastening ring C as in the former
case.
Having thus described the nature of the said Invention, and in what
manner the same is to be performed, I hereby declare that what I claim
as of my Invention with reference to slide valve gear is,—
First. The expansive motion with one excentric and two straps
thereon actuated by one pair of wedges with the motion communicated
directly to one valve spindle through one excentric rod, and transmitted
to the other valve spindle through a bell crank on a cross shaft, as
described.
Secondly. The said expansive motion communicated to the valve
spindles through two bell cranks, as described.
With reference to division plates between slide valves I claim, the
application to the plate of two parts or rings with a packing ring

page_text: between them and a spring pressing the rings respectively against the
backs of the valves.
With reference to axle boxes I claim, the formation of the upper or
both brasses and their scats with a convex side and with the contre parts
formed to give a limited amount of play to accommodate the brass or
brasses to the movements of the axle, also in the use of cast-iron.
oscillating backs with brasses of ordinary form.
And with reference to the mode of fastening tyres on railway wheels
I claim, the insertion of a wedge-shaped ring in a recess formed. partly
in the tyre and partly in the wheel, as described.
In witness whereof, I, the said Thomas Weatherburn Dodds, have
hereunto set my hand and seal, the Fourth day of September,
in the year of our Lord One thousand cight hundred and
seventy-one.
THOMAS WEATHERBURN DODDS. (L.s.)
Witness,
WILLIAM BURROW,
Clerk,
Stoke-upon-Trent.