Im- PROVEMENTS IN APPARATUS FOR WORKING THE SLIDE VALVES OF STEAM AND OTHER ENGINES
Year: 1875

page_text: LETTERS PATENT to Martin Henry Gerring, of Blenheim Park,
Woodstock, in the County of Oxford, for the Invention of "Im-
PROVEMENTS IN APPARATUS FOR WORKING THE SLIDE VALVES OF STEAM AND
OTHER ENGINES."
Sealed the 29th February 1876, and dated the 30th September 1875.
PROVISIONAL SPECIFICATION left by the said Martin Henry Gerring
at the Office of the Commissioners of Patents, with his Petition,
on the 30th September 1875.
I, MARTIN HENRY GERRING, of Blenheim Park, Woodstock, in the
County of Oxford, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN APPARATUS FOR WORKING THE SLIDE VALVES OF STEAM
AND OTHER ENGINES," to be as follows :-
-
This Invention has for its object to provide a ready means of altering
the throw or reversing the position of an eccentric on the crank shaft of
a steam engine so as to modify the travel of the valve or reverse the
engine. For this purpose the eccentric is carried by a tubular collar

page_text: surrrounding the crank shaft, and embracing at one end an eccentric
collar fixed on the shaft, whilst at the other end it embraces a cor-
responding eccentric collar, which is free to slide along the shaft, but
not to turn around it. This eccentric collar has a spiral groove formed
partly around its periphery, into which is received a key fast with the
eccentric. The sliding collar can be shifted to and fro by means of
a lever or otherwise.
When the sliding eccentric collar is moved in either direction along
the shaft the spiral groove around it causes the position of the eccentric
to be shifted, and when it has been moved from one extremity of its
travel to the other it will have shifted the eccentric to the opposite side
of the shaft to that at which it originally stood, and will have reversed
the engine. Whilst in the centre of its traverse the eccentric will be
concentric with the shaft, and no movement will be transmitted to the
slide valve.
In place of one eccentric only being carried by the tubular collar two
eccentrics may be carried by it, the second eccentric being for working
the slide valve of a second cylinder.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Martin Henry Gerring in the Great Seal Patent
Office on the 30th March 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MARTIN
HENRY GERRING, of Blenheim Park, Woodstock, in the County of
Oxford, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirtieth day of September, in the
year of our Lord One thousand eight hundred and seventy-five, in
the thirty-ninth year of Her reign, did, for Herself, Her heirs
and successors, give and grant unto me, tho said Martin Henry
Gerring, Her special license that I, the said Martin Henry Gerring, &
my executors, administrators, and assigns, or such others as I, the
said Martin Henry Gerring, my executors, administrators, and assigns,
should at any time agree with, and no others, from time to time and

page_text: 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 APPARATUS FOR WORKING
THE SLIDE VALVES OF STEAM AND OTHER ENGINES," upon the condition
(amongst others) that I, the said Martin Henry Gerring, my executors
or administrators, by an instrument in writing under my, or their, or
one of their hands and seals, should particularly describe and ascer-
tain 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 Martin Henry Gerring, do hereby
declare the nature of the said Invention, and in what manner tho samo
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 to provide a ready means of altering
the throw or reversing the position of an eccentric on the crank shaft of
a steam engine so as to modify the travel of the valve or reverso the
engine. For this purpose the eccentric is carried by a tubular collar
surrounding the crank shaft and embracing at one end an eccentric
collar fixed on the shaft, whilst at the other end it embraces a cor-
responding eccentric collar, which is free to slide along the shaft, but
not to turn around it. This eccentric collar has a spiral groove formed
partly around its periphery, into which is received a key fast with the
eccentric. The sliding collar can be shifted to and fro by means of
a lever or otherwise.
When the sliding eccentric collar is moved in either direction along
the shaft the spiral groove around it causes the position of the eccentric
to be shifted, and when it has been moved from one extremity of its
travel to the other it will have shifted the eccentric to the opposite side
of the shaft to that at which it originally stood, and will have reversed
the engine. Whilst in the centre of its traverse the eccentric will be
concentric with the shaft, and no movement will be transmitted to the
slido valve.
In place of one eccentric only being carried by the tubular collar two
eccentrics may be carried by it, the second eccentric being for working

page_text: In the Drawings hereunto annexed I have shown an apparatus
arranged in the manner above described for working the slido valves of
steam and other engines.
Figure 1 shows a side elevation, and Figure 2 a longitudinal section of
the apparatus; Figure 3 shows a transverse section taken through the
shaft at a, b, Figure 1; and Figure 4, a transverse section taken through
c, d, Figure 2.
In these Figures A is a portion of the crank shaft of a steam or other
engine; B is the eccentric for giving motion to the slide valve in the
ordinary manner. This eccentric is carried by the tubular collar C, 1
which at one end embraces an eccentric D fixed upon the shaft, and is
free to turn around this eccentric, but is prevented from moving endwise
by means of a divided ring C' secured to its interior and lodged in a
groove cut around the eccentric D. The tubular collar C at its opposite
end embraces a similar eccentric E, which is capable of sliding endwise 1
along the shaft, but is prevented from turning around it by a key F.
Around the circumference of this eccentric is a spiral groove G, into
which is received a spiral feather H, secured by screws I to the interior
of the collar C. Around the outer end of the eccentric E is a grooved
flange K concentric with the crank shaft. This flange is to be embraced a
by a collar not shown in the Drawing.
The collar may be acted upon by a lever or otherwise to shift the
eccentric to and fro longitudinally of the shaft. As the collar is thus
shifted endwise the spiral groove around it causes the tubular collar O
and the eccentric B which it carries to turn around the shaft.
IC
The red lines and y, Figure 3, show the two extreme positions of the
cccentric with reference to the crank of the crank shaft. When the
collar E has been shifted from one extremity of its traverse to the other
the eccentric B will have been turned somewhat more than a quarter of
a revolution around the shaft A, and will have reversed the engine. At 8
the same time a proper amount of lead will be given to the valve in
which ever direction the ongine is being driven, and the full travel will
be given to the slide valve. As the collar E is shifted towards its central
position from either extremity of its travel the amount of movement
given to the valve will be decreased, and at the centre of its traverse the 8
eccentric B will be concentric with the crank shaft and no movement
will be transmitted to the slide valve.

page_text: Having thus described the nature of my Invention and the manner of
performing the same, I would have it understood that I claim the com-
bined arrangement of apparatus substantially as herein described for
working the slide valves of steam and other engines.
In witness whereof, I, the said Martin Henry Gerring, have hero-
unto set my hand and seal, this Twenty-seventh day of March,
in the year of our Lord One thousand eight hundred and
seventy-six.