IMPROVEMENTS IN MECHANICAL ARRANGEMENTS FOR OBTAINING REVERSE ROTARY MOTION FROM ONE CENTRE, PARTICULARLY APPLICABLE TO SCREW PROPULSION WHEN MORE THAN ONE SCREW IS ADOPTEN
Year: 1872

page_text: LETTERS PATENT to James Vivian, of Falmouth, in the County of
Cornwall, and Henry Somerset Mackenzie, of the same Place,
Steam Ship Owner, for the Invention of "IMPROVEMENTS IN MECHANICAL
ARRANGEMENTS FOR OBTAINING REVERSE ROTARY MOTION FROM ONE CENTRE,
PARTICULARLY APPLICABLE TO SCREW PROPULSION WHEN MORE THAN ONE SCREW
IS ADOPTEN
"
Sealed the 21st January 1873, and dated the 25th July 1872.
PROVISIONAL SPECIFICATION left by the said James Vivian and
Henry Somerset Mackenzie at the Office of the Commissioners of
Patents, with their Petition, on the 25th July 1872.
We, JAMES VIVIAN, of Falmouth, in the County of Cornwall, and
HENRY SOMERSET MACKENZIE, of the same Place, Steam Ship Owner,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN MECHANICAL ARRANGEMENTS FOR OBTAINING REVERSE ROTARY MOTION FROM
ONE CENTRE, PARTICULARLY APPLICABLE TO SCREW PROPULSION WHEN MORE THAN
ONE SCREW IS ADOPTED," to be as follows:-
:―
The obiect of this Invention consists in mechanical arrangements for

page_text: applicable for working more than one screw on concentric, external, and
internal shafting (working in opposite directions one to the other), and
without using toothed gear for the purpose of procuring such opposite
or reverse motion.
To effect the above objects I adopt substantially the arrangements
hereafter described. To the piston of the working cylinder of the engine
I attach two piston rods placed parallel to each other, the lower ends of
.which are secured to looped and slotted cross heads; the loops referred
to being on the upper and lower sides of the cross heads, such loops
securing the propeller shaft in them, that is, sometimes through the
top loop and sometimes through the bottom loop in accordance with
the working of the engine. In the horizontal slot of each cross head
a slide works, which is secured to the end of a crank belonging to it,
and works either the exterior or interior screw shaft, as the case may be,
and when set to work in reverse directions the required opposite or
reverse motion will thus be attained; and provided the distance between
the bottom of one loop and the top of the other corresponds with the
throw of the crank, one crank will always pass the other without
difficulty. Instead of two or more piston rods and two or more cross
heads being adopted, a single piston rod might be used connected to a
cross pin with guides at each end sliding on guide rods, to which cross
pin one rod connected with a crank and another rod connected to the
slotted cross head, above described, would be attached.
In the arrangements described it is assumed that the cylinders are
inverted vertical ones, but they might be otherwise arranged and the
whole system would still operate as above described.
If desired the slotted ends of cranks could be placed in starting so as
to work in same directions instead of different directions.
Similar arrangements could be applied to other purposes than screw
propellers. And if thought desirable, different rates of reverse motion
for the interior and exterior shafts might be produced by having the
piston rods connected to different cylinders and worked at different
velocities.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Vivian and Henry Somerset Mackenzie in
the Great Seal Patent Office on the 25th January 1873.
TO. ALL TO WHOM THESE PRESENTS SHALL COME, we, JAMES
VIVIAN, of Falmouth, in the County of Cornwall, and HENRY SOMERSET
MACKENZIE, of the same Place, Steam Ship Owner, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-fifth day of July, in the year
of our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said James Vivian and Henry Somerset
Mackenzie, Her special licence that we, the said James Vivian and
Henry Somerset Mackenzie, our executors, administrators, and assigns,
or such others as we, the said James Vivian and Henry Somerset
Mackenzie, our 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 MECHANICAL ARRANGEMENTS FOR OBTAINING
REVERSE ROTARY MOTION FROM ONE CENTRE, PARTICULARLY APPLICABLE TO SCREW
PROPULSION WHEN MORE THAN ONE SCREW IS ADOPTED," upon the condition
(amongst others) that we, the said James Vivian and Henry Somerset
Mackenzie, our executors or administrators, 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 James Vivian and Henry Somerset
Mackenzie, 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 Drawings accompanying these Presents and herein-after referred
to, that is to say :-
The object of this Invention is to obtain reverse rotary motion from
one centre, that is, each screw may be made to move in one direction or

page_text: .
in a contrary direction as required, or the screws may be made to move
in opposite directions at the same time, without toothed gear, and is
particularly applicable for working more than one screw propeller on
concentric internal and external shafts, though our improvements may
be applied to any other work for which similar motions are required.
To effect the above object we adopt substantially the arrangements
hereafter described. A looped slotted cross head is attached to the
piston of a working cylinder by one or more piston rods, the loops being
formed in the metal on the opposite sides of the slot in the middle, so as
to permit the internal shafting to revolve in them without hindrance
any
during the working of the said cross head; these loops being made in
proportion to the length of the crank to be employed; in the slot is fitted
a peculiarly constructed slot link or block bolted together in two parts
sufficiently long to overlap both edges of the gap caused by the loops,
without being touched by the said internal shafting during work. This
block is also made in due proportion to the length of the crank, and it
encircles the crank pin of the external shaft, giving by its motion along
the slot the desired similar or reverse rotary motion to the external shaft.
To make this clearer, assuming the cylinder to be inverted and one
internal with one external concentric shaft to be worked, we attach to
the piston two piston rods, one of which works by means of an ordinary
connecting rod the internal shaft, while the other being secured to the
head of a looped slotted cross head, such as described above, gives
revolution to the external shaft, and by placing the slot link or block at
starting on the same or the opposite side of the loop to the crank pin of
the internal shaft the required motion is obtained.
い
Instead of a connecting rod and one looped slotted cross head, two or
more cross heads may be adopted or one cross head only, so constructed
that two blocks shall work in the looped slot simultaneously, these
being secured to the crank pins of an internal and external shaft to drive
them in the same or opposite directions at a uniform speed. And by
employing a separate cylinder for each shaft to be driven various rates
of speed may be given to each, and the required direction of rotary
motion obtained. These looped slotted cross heads are also applicable
to other purposes than screw propellers wherever it is desirable to avoid
the employment of toothed gear.
In carrying out our said Invention, the form and construction of the
looped slotted cross head may be modified to suit the circumstances;

page_text: a guide or guides may be secured to the head or the sides of the loop or:
the other parts of the cross head (see Drawing A), or guides may be
arranged at the extremities (as in Drawing E), and the mode of attach-
ment of the cross head to a piston or pistons may also be varied; the
faces of the opposite parts of the oross head may also be kept parallel by:
other means than the adjusting screw bolts represented in the Drawings
and marked 9.
DESCRIPTION OF THE SAID DRAWINGS.
A shows the looped slotted cross head when it is attached to a piston
by only one piston rod, having also a single guide at the head of the
opposite loop. In this Drawing the piston is assumed to be midway in
the inverted cylinder. B is a view of the same looking down on it.
C represents the same looking up from beneath, and when the piston is
at the head of the inverted cylinder. 1 is an internal shaft; 2, an
external shaft concentric with it; 3 is the crank of the external shaft;
4, the piston, and 5, the slot link or block; 6, the crank pin.or arm of
external shaft; 7, the guides; 8 is the crank of an internal shaft when
cross head works two concentric shafts at uniform speed; and 9, marks
the adjusting bolts for the faces of the cross head.
D shows the face of the slot link or block with the heads of the
bolts securing the two parts round the crank pin countersunk in the
metal.
E is a view of the looped slotted cross head with guides (7, 7,) at the
extremities. In this Drawing the piston is assumed to be at the head
of the inverted cylinder, and the upper loop consequently close down on
the internal shaft, beneath which the slot block then passes, taking the
crank pin of the external shaft with it.
F represents the arrangement of the cranks for external and internal
concentric shafts when only one cross head is employed, having two
blocks in the looped slot; in this Drawing 8 is the crank of the internal
shaft.
Having now particularly described and ascertained the nature of the
said Invention, and in what manner the same is to be performed or
carried out in practice, we hereby declare that we claim the herein
described Invention of improvements in mechanical arrangements
for obtaining reverse rotary motion from one centre, particularly
}

page_text: JAMES VIVIAN.
(L.S.)
Witnesses,
RICHARD SPRY,
Accountant,
Falmouth.
THOMAS GOODMAN,
Accountant,
Falmouth.
H. SOMERSET MACKENZIE. (L.S.)