IMPROVEMENTS IN DUPLEX STEAM ENGINES
Year: 1865

page_text: LETTERS PATENT to Norman Willis Wheeler, of Brooklyn, in the
County of Kings, State of New York, and United State of America,
the Tution is Tern
COMPLETE SPECIFICATION filed by the said Norman Willis Wheeler at
the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 27th December 1865, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, NORMAN
WILLIS WHEELER, of Brooklyn, in the County of Kings, State of New
York, and United States of America, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
DUPLEX STEAM ENGINES," and have petitioned Her Majesty to grant unto me,
my executors, administrators, and assigns, Her Royal Letters Patent for the
same, and have made solemn Declaration that I am the true and first
Inventor thereof.
NOW KNOW YE, that I, the said Norman Willis Wheeler, do hereby
declare that the following Complete Specification under my hand and seal
fully describes and ascertains the nature of the said Invention, and in
what manner the same is to be performed in and by the following state-
ment:

page_text: The first part of my Invention consists in the employment of a beam
vibrating on its center with links connecting its ends with two pistons
respectively, and capable of moving bodily with strong parallel motion or
equivalent device to keep its center in a path parallel to the axes of the
cylinders, the crank being actuated either directly or indirectly from this
mechanism in such manner that one piston is at or near the middle of its
stroke, while its companion is at the end of its stroke.
The second part of my Invention consists in the combination of trunks
with the above, as herein-after shown and described.
The third part of my Invention consists in a peculiar construction of
brasses and straps taking. hold of the crank pin in combination with the
other parts as herein-after shown and described.
My Invention is intended more especially for marine purposes, but may
serve in any ordinary position.
I will now proceed to describe what I consider the best mode of carrying.
out my Invention, reference being had to the accompanying Drawings, with
letters of reference marked thereon, in which Figure 1 represents a plan,
and Figure 11. an elevation of such engine; like letters of reference
indicating the same parts in the several Figures.
Two working cylinders a, a, are secured upon the base plate D, D, with
their proper pistons, valves, steam chests B, B, valve rods i, i, and piston
rods or trunks h, h, and other appurtenances, and upon the upper ends of
the cylinders is erected a strong frame E, E, having bearings fitted on the
lower side for the main shaft c, which carries the crank R, and also proper.
brackets f. ff. f, fitted with the bearings H, H, H, H, in which are
mounted the rocking shafts g, g; secured to these shafts g, g, are the
rods K, K, K, K, having pins n, n, n, n, in their opposite extremities,
which pins are connected to each other and to the center pin of the beam
o, o, in such a way as to form a parallel motion for the center pin m, and
cause it when the engine is in motion to traverse accurately or nearly so in
a vertical line over the shaft C. The beam o, o, o, is made by preference
in two parts in the general form of an isosceles triangle and united by the
pins t, t, and m, the pin m passing through a boss upon the upper end of
the strut s, while the lower end of the strut s is formed in such manner
that with the beams a fair seat for the crank brasses will be secured, the
whole being bolted and riveted securely together. The strap p, p, passes
around the crank pin and lower brass thereof, and terminates at the
most part in two bolt ends at u, u, which pass through ears formed upon
the boss of the strut s, so that by turning the nuts u, u, the brasses of the
upper-

page_text: -
crank may be adjusted. The working pistons, not represented, are attached
to the pins t, t, by means of the links j, j. The engine may have any
convenient known valve gear and other ordinary appurtenances.
When the engine is in motion the crank will traverse around as indicated
by dotted lines in Figure II. The centers of the pins t, t, will traverse
the paths indicated by the dotted lines, and the respective positions of the
parts will in their successive relations to each other correspond to the
numbers marked upon the respective paths. The pistons will traverse
from end to end of the working cylinders in their proper relations thereto,
so that when one piston is at the extreme of its throw the other will be at
mid throw. The position last described may be deviated from within
reasonable limits by varying the proportions of the parts; but I prefer to
adhere thereto, and do this very accurately when the lines joining the two
pins t, t, and the crank pin R form the sides of an isosceles triangle whose
hight is equal to half the base, as indicated in the Drawings.
It will be perceived upon inspection that the throw of the pistons is
greater than the throw of the crank. This may at first view be thought
likely to produce great friction, but this is not the case. The tendency to
produce friction and strains in my engine is more than counterbalanced by
the fact that the stress upon the journals is relieved, as compared with
ordinary double engines, because much of the stress due to the deflection
of the forces is transferred directly from member to member of the mecha-
nism, and because the resultants of the forces derived from the pistons are
generally more nearly in the direction of the crank motion than in ordinary
engines.
This construction may be modified in various ways; for instance, the
whole structure may be inverted or inclined or laid upon its side, or the
parallel motion may be replaced by simple radius rods or by guides, or yet
again the triangular beam o may be dispensed with by connecting the pins
1, t, to the crank pin by connecting rods, and extending the rods K, K, K, K,
and attaching them to the pins; but either of these modifications applied
under ordinary circumstances would, I think, result in more or less dis-
advantage. A useful modification in many cases would be to reverse
the beam and place the shaft C twice the hight of the beam above the
position in which it is shown. I consider all these mere colorable variations
of my Invention.
Having now fully described my Invention, what I claim as new and
useful, and which I desire to secure by Letters Patent, is as follows:-
First, I claim connecting the two working pistons with the crank by

page_text: means of the beam o, o, links j, j, and the parallel motion k, l, or their
equivalents, substantially as and for the purposes described:
Second, I claim in connection with the above the slender trunks h, h,
adapted to allow the slight vibratory movements of the links, and thus to
render the engine very compact without the large trunks required for
ordinary trunk engines.
Third, I claim the strap p mounted and operating as described in com-
bination with the beam o, or its equivalent, substantially as herein set
forth.
In witness whereof, I; the said Norman Willis Wheeler, have hereunto
set my hand and seal, this First day of December, 1865..
NORMAN WILLIS WHEELER. (L.8.)