IMPROVEMENTS IN STEAM ENGINES
Year: 1875

page_text: LETTERS PATENT to Alfred Hilton Legge and John Stevenson
Richardson, both of Darlington, in tho County of Durham,
Accountants, for the Invention of "IMPROVEMENTS IN STEAM ENGINES."
Accountants, for the Invention of
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IMPROVEMENTS IN STEAM ENGINES."
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PROVISIONAL SPECIFICATION left by the said Alfred Hilton Legge
and John Stevenson Richardson at the Office of the Commissioners
of Patents, with their Petition, on the 29th May 1875.
We, ALFRED HILTON LEGGE and JOHN STEVENSON RICHARDSON, both
of Darlington, in the County of Durham, Accountants, do hereby declare
the nature of the said Invention for "IMPROVEMENTS IN STEAM ENGINES,”
to be as follows:-
This Invention relates to that class of steam engines in which the
requisite rotary power is obtained by means of one or two cranks upon
a crank shaft being acted upon by a piston rod, and consists in so
constructing such engines that they are capable of being worked with a
minimum amount of friction and without waste of power.
Instead of constructing the crank shaft with one or at most two
cranks, as is at present the case, according to this Invention three

page_text: cranks are formed on the crank shaft, the two outside cranks being on
the opposite side of the centre line of the crank shaft to that on which
the intermediate crank is placed. The two outside cranks are connected
to two connecting rods, attached to a crosshead fixed to the rod of a
piston which works in a cylinder in the ordinary way. A second piston.
is placed in the same cylinder, but with its rod passing through the
opposite end to that with the cross head, and which second piston rod
is attached by a connecting rod to the intermediate crank. The steam
is admitted on cach side of both pistons alternately, so that whilst the
piston connected to the intermediate crank is pulling, that connected to
the two outside cranks is pushing, and vice versa, thus obviating the loss
of power and the great amount of friction and wear and tear in engines
as at present constructed.
Instead of having two pistons working in the cylinder as herein-before
described the two connecting rods may be attached to the cylinder
itself by any convenient means, the cylinder being caused to slide upon
a suitable bed, thus taking the place of the extra piston. The steam in
this case is admitted through suitable steam ports on cach side of the
piston alternately, and the length of the stroke of the piston and the
stroke of the cylinder may be either equal or unequal.
It will be understood that in the case of double engines, that is,
engines in which two cylinders are working, two cranks on tho samo
crank shaft, according to this Invention three cranks must be provided
to each cylinder, and each cylinder must also be provided with an extra
piston, or caused to slide as herein-before described, but the cranks will
not be required to be nearly the same size as those at present in use,
by this means effecting a considerable saving in the space required for
their "throw."
In some cases, instead of the two pistons working through the opposito
ends of the cylinder, they may be placed one above the other, the rod of
the lower one passing through the upper one, which would be made
hollow and suitably packed for that purpose. The rod of the lower
piston would work the intermediate crank and the upper piston the two
side cranks.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alfred Hilton Legge and John Stevenson
Richardson, in the Great Seal Patent Office on the 29th November
1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, ALFRED
HILTON LEGGE and JOHN STEVENSON RICHARDSON, both of Darlington,
in the County of Durham, Accountants, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of May, 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 suc-
cessors, give and grant unto us, the said Alfred Hilton Legge and
John Stevenson Richardson, Her special licence, that we, the said
Alfred Hilton Legge and John Stevenson Richardson, our executors,
administrators, and assigns, or such others as we, the said Alfred
Hilton Legge and John Stevenson Richardson, our executors, adminis-
trators, and assigns, should at any time agree with, and no others,
from time to time and at all times thercafter 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 STEAM
ENGINES," upon the condition (amongst others) that we, the said Alfred
Hilton Legge and John Stevenson Richardson, our executors or admini-
strators, by an instrument in writing under our, 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 we, the said Alfred Hilton Legge and John
Stevenson Richardson, do hereby declare the nature of our said
Invention, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement,
reference being had to the accompanying Drawings and to the figures
and letters marked thereon, that is to say :-
-
Our said Invention relates to that class of steam engines in which the
requisite rotary motion is obtained from the reciprocating motion of a

page_text: piston working in a cylinder acting upon a crank or cranks upon a
crank shaft, and consists in so constructing such engines, whether
horizontal or vertical, that they are capable of being worked with a
minimum amount of friction and without waste of power.
Instead of constructing the crank shaft with one or at most two
cranks to each cylinder, as is at present the case, according to this
Invention we form three cranks thereon, the two outside cranks being
on the opposite side of the centre line of the crank shaft to that on
which the intermediate crank is placed. The two outer cranks aro
connected to two connecting rods, attached to the rod of a piston which
works in a cylinder of the ordinary description, but having a second
piston placed therein, the rod of which second piston passes through the
opposite end of the cylinder to that through which the first mentioned
piston rod passes, and is attached by a connecting rod to tho inter-
mediate crank. The steam is admitted on each side of both pistons 1
alternately, so that whilst that connected to the intermediate crank is
pulling, the one connected to the two outside cranks is pushing, and
vice versa, thus obviating the loss of power and the great amount of
friction and wear and tear in engines as at present constructed.
We will now proceed to refer to Sheet 1 of the accompanying
Drawings, from which the nature of this part of our said Invention will
be more clearly understood.
Figure 1 is a side elevation; Figure 2, a plan; Figure 3, a longi-
tudinal section; and Figure 4 an end view of a horizontal engino
constructed as herein-before described; Figure 5 being a section through
the line X, Z, Figure 1, shewing the steam passages.
The same letters of reference indicate like parts in all the Figures.
A is the cylinder, B the steam chest, C and D the two pistons with
their rods E and F; G is the crank shaft, H being the intermediate
crank, and I and J the two outer cranks; K, K, are the two connecting a
rods attached by the cross head L to the piston rod E, and connecting
the latter with the two cranks I and J; M is the rod connecting the
piston rod F with the intermediate crank H; N is the slide valve
arrangement which may be of any convenient description, the passages
through which the steam enters into the cylinder being shewn at O, P, a
and Q.

page_text: Having thus declared and ascertained the nature of our said Invention
and in what manner the same is to be performed, we would observe in
conclusion that what we consider novel and original, and therefore claim
as constituting the Invention secured to us by the herein-before in part
recited Letters Patent, arc,-
First. The combination and arrangement of two pistons working in
one cylinder with three cranks on one shaft in the construction of steam
engines, in the manner and for the purposes hercin-before set forth and
described, or any mere modifications thereof.
And, secondly. The combination and arrangement of a sliding cylinder
with three cranks on one shaft in the construction of steam engines, in
the manner and for the purposes herein-before set forth and described,
or any mero modifications thereof.
In witness whereof, we, the said Alfred Hilton Legge and John
Stevenson Richardson, have hereunto set our hands and seals,
this Twenty-fifth day of November, in the year of our Lord One
thousand oight hundred and seventy-five.
Witness,
R. S. MORDAUNT VAUGHAN,
Patent Agent,
Darlington.
A. H. LEGGE.
(L.S.)
J. S. RICHARDSON.
(L.S.)