IMPROVEMENTS IN MACHINERY OR APPARATUS FOR THE TRANSMISSION AND CONVERSION OF MOTIVE POWER
Year: 1855

page_text: application for Letters Patent was not given within the time prescribed
by the Act.)....
PROVISIONAL SPECIFICATION left by John Henry Johnson at the Office
of the Commissioners of Patents, with his Petition, on the 8th October
1855. A communication.
Ex 73
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, and of Glasgow, North Britain, Gentleman, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN MACHINERY OR APPARATUS
FOR THE TRANSMISSION AND CONVERSION OF MOTIVE POWER," a communication
from Jules François Louis Etienne Lesénéschal, of Paris, in the Empire of
France, Engraver, to be as follows:-
This Invention relates to a new method of transmitting motive power and of
converting reciprocating or alternate rectilinear motion into continuous circular
motion, or vice versâ, and consists in attaching to the first mover two rollers,
between which slides a connecting rod at right angles to the line of movement,
which connecting rod is coupled to two cranks, one at each of its ends. These
cranks are keyed each upon one end of their respective shafts, which are
parallel with each other; at the other ends of these shafts are respectively
keyed two other cranks, which have a position at right angles to the former
cranks, and are coupled together by a second connecting rod. Supposing the
journals of the rollers above named to be affixed to a cross head connected with
a vertical horizontal or inclined rod, and that this rod has an alternate recti-

page_text: linear motion, it will be evident that the connecting rod which passes between
the rollers will be carried forward also, and at the same time will be caused to
slide in a direction perpendicular or at right angles to the line of motion of
the rod or first mover, and this combined movement of the connecting rod will
cause the crank pins to which it is coupled, each to describe an arc around its
axis, and thus to communicate a continuous rotatory motion to the shafts upon
which the cranks are keyed. The contrary effect, viz., the converting of
rotatory motion into alternate rectilinear or reciprocating motion, may be
produced by means of an analogous but reversed arrangement.
The arrangement of these two shafts, coupled by two connecting rods and
four cranks (two of which are keyed at right angles to the other two in order
to avoid what is called a "dead point "), not only ensures great regularity of
movement, but also in vertical steam engines allows the crank shaft to be
brought much lower down without shortening the connecting rod, thus rendering
them more suitable to be employed as marine engines in vessels propelled by
paddle wheels. By giving to the rollers (which bear upon their journals the
whole of the pressure) a circumference equal to the length of the stroke of
the piston, the friction may be reduced to a minimum as compared to that
produced by the ordinary method of transforming alternate rectilinear motion
into continuous circular motion, and vice versa. It will be evident that this
new method of transmitting motive power and converting motion is equally
applicable to steam engines, whether stationary, locomotive, or marine, with
either vertical, horizontal, or diagonal cylinders, and to all other machines
wherein the power is required to be transmitted and converted, as above
described.