IMPROVE- MENTS IN REVERSING GEAR FOR STEAM ENGINES."
Year: 1874

page_text: LETTERS PATENT to Henry Dubs, of Glasgow, in the County of
Lanark, North Britain, Engineer, for the Invention of "IMPROVE-
MENTS IN REVERSING GEAR FOR STEAM ENGINES."
PROVISIONAL SPECIFICATION left by the said Henry Dubs at the
Office of the Commissioners of Patents, with his Petition, on the
29th October 1874.
I, HENRY DUBS, of Glasgow, in the County of Lanark, North Britain,
Engineer, do hereby declare the nature of the said Invention for "Iм-
PROVEMENTS IN REVERSING GEAR FOR STEAM ENGINES," to be as follows, that
is to say :-
This Invention relates to improved reversing gear for steam engines,
such gear being designed so that the reversing lever may either be
moved rapidly through the whole or any large part of its range, or be
adjusted slowly and accurately through a small arc.
The improved gear is intended for link motion or similar valua

page_text: and is of especial advantage for locomotives or for any steam engines in
which reversals are frequently required on the one hand, and small
adjustments on the other.
The small adjustments referred to are for the purpose of regulating
the degree of expansion to meet varying demands on the power of the
engine, as is well understood.
In the improved reversing gear a screw spindle of uniform diameter,
and having a hand wheel fixed on one end, is held in bearings in front
of the reversal plate or frame plate, which carries the reversing gear.
The reversing lever, which in its middle position is at right angles to
the screw spindle, is jointed to a tubular piece capable of sliding along
the screw spindle, being bored to fit casily on the outer surface of the
screw thread. The lower fulcrum end of the lever has fixed to it a pin
capable of turning in a small rectangular block, which is guided in a
short groove in a plate or bracket fixed to the reversal plate. This
movement of the fulcrum end of the lever is provided to admit of the
part of the lever jointed to the tubular picce moving in the straight line
of the screw spindle instead of in an arc. The tubular piece is formed
with a mortise in which a catch block is fitted to work, and this catch
block is formed with segmental helical teeth, which, when the block is :
moved inwards, fit in between the threads of the screw spindle. A pin
capable of turning in the catch block projects therefrom, and has a
groove formed across its projecting part to fit a small arc-shaped piece
formed on a slide on the lover; and this slide is connected to the
usual small catch lever on the side of the handle of the main lever.
When the driver or engineer wishes to move the lever quickly he by
means of the catch lever takes the catch block clear out of the screw
threads, and moves the lever over, just as with the ordinary reversing
lever.
On the other hand when the driver or engineer wishes to adjust the
lever through a small space only he turns the screw spindle, which
acting on the teeth of the catch block (held in gear with the screw
spindle by the action of a spring on the catch lever) moves the lever as
far as required. The catch block is connected in the manner described
to the slide on the lever, so as to accomodate the angular change of
position of the lever.

page_text: The grades of expansion may be conveniently marked on the edge of
the reversal plate, and a point projecting from the lever may serve to
show the position of the lever in connection therewith.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Henry Dubs in the Great Seal Patent Office on
the 28th April 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
DUBS, of Glasgow, in the County of Lanark, North Britain, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of October, in the
year of our Lord One thousand eight hundred and seventy-four, in
the thirty-eighth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said Henry Dubs, Her
special licence that I, the said Henry Dubs, my executors, admi-
nistrators, and assigns, or such others as I, the said Henry Dubs,
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 REVERSING GEAR FOR STEAM ENGINES," upon the con-
dition (amongst others) that I, the said Henry Dubs, 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 Henry Dubs, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement in writing, reference being had to the accompanying
Drawings, that is to say :—
My said Invention relates to improved reversing gear for steam.

page_text: engines, such gear being designed so that the reversing lever may either
be moved rapidly through the whole or any large part of its range, or be
adjusted slowly and accurately through a small arc.
My improved gear is intended for link motion or similar valve gear,
and is of especial advantage for locomotives, or for any steam engines in &
which reversals are frequently required on the one hand, and small
adjustments on the other.
The small adjustments referred to arc for the purpose of regulating
the degree of expansion to meet varying demands on the power of the
engine, as is well understood.
And in order that my said Invention, and the manner of performing
the same may be properly understood, I hereunto append a Sheet of
explanatory Drawings to be herein-after referred to, and representing
my improved reversing gear arranged as for a locomotive.
In these Drawings the same reference numerals are used to mark the 1
same or like parts wherever they are repeated.
Figure 1 of the Drawings is a sectional elevation, and Figure 2 is a
vertical section as at right angles to Figure 1, but with the reversing
lever 1 shown inclined in Figure 1, supposed to be vertical in
Figure 2.
In my improved reversing gear a horizontal screw spindle 2 of uniform
diameter, and having a hand wheel 3 fixed on one end is held in
bearings 4 in front of the reversal plate 5, that is, the frame plate which
carries the reversing gear. The reversing lever 1, which in its middle
position is at right angles to the screw spindle 2, is jointed to a tubular
piece 6, capable of sliding along the screw spindle 2, being bored to fit
easily on the outer surface of the screw thread. The tubular piece 6,
which is made by preference of gun metal, is formed with trunnions 7
which enter joint eyes, one of them in the lever 1 itself, and the other
in a bow piece 8, which is bolted to the lever 1 after the tubular piece 6
has been put in its place. The lower or fulcrum end of the lever 1 is
forked, and has fixed to it a pin 9, capable of turning in a small rectan-
gular block 10, which is guided in a short vertical groove or slot in a
plate or bracket 11 fixed to the reversal plate 5. This movement of the
fulcrum end of the lever 1 is provided to admit of the part of the lever
jointed to the tubular piece 6 moving in the straight line of the screw
]

page_text: spindle 2, instead of in an arc. The tubular piece 6 is formed with a
mortise in which a catch block 12 is fitted to work, and this catch block 12
is formed with segmental helical teeth, which, when the block is moved
inwards fit in between the threads of the screw spindle 2. A pin 13,
capable of turning in an eye in the catch block 12, projects therefrom,
and has a groove formed across its projecting part to fit a small arc-
shaped piece 14 formed on a slide 15 on the lever 1. This slide 15 con-
sists of two parts, a back part with the arc 14 on it, and with a tongue
working in a slot in the lever 1, and a front plate, which, being bolted
to the tongue, secures the whole slide in its place. The slide 15 is con-
nected by a link 16 to the usual small catch lover 17 on the side of the
handle of the main lever 1, and is acted on by a spring 18, which tends
to move it so as to put the catch block 12 in gear with the screw
spindle 2.
When the driver or engineer wishes to move the lever 1 quickly he,
by means of the catch lover 17, takes the catch block 12 clear out of
the screw threads, and moves the lever 1 over, just as with the ordinary
reversing lever.
On the other hand, when the driver or engineer wishes to adjust the
lever 1 through a small space only he turns the screw spindle 2, which,
acting on the teeth of the catch block 12 (held in gear with the screw
spindle by the action of the spring 18), moves the lever as far as
required. The catch block 12 is connected to the lever slide 15 in the
manner herein-before described, so that the parts may accommodate
themselves to the angular change of position of the lever 1.
The various grades of expansion may be conveniently marked on the
top edge of the reversal plate 5, and a point 19 projecting from the
lever 1 may serve to show the position of the lever in connection there-
with.
Having thus particularly described my said Invention and the manner
of performing the same, I have to state that I do not restrict myself to
the precise details herein described or delineated, but that what I believe
to be novel and original, and claim as the Invention secured to me by
the herein-before in part recited Letters Patent is, the arranging or
combining of parts to form reversing gear for steam engines, substan-
tially in the improved manner herein-before described; and more
particularly the jointing of the main lever 1 upon a tubular piece 6,

page_text: which moves along the screw spindle 2, and which is fitted with a
movable catch block 12 uniformly fitting the screw threads, whatever
may be the position of the lever.
In witness whereof, I, the said Henry Dubs, have hereunto set
my hand and seal, this Twenty-seventh day of April, in the 5
year of our Lord One thousand eight hundred and seventy-
five.
.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
HENRY DUBS. (L.S.)