IMPROVEMENTS IN DRIVING GEAR FOR LOCOMOTIVE ENGINES
Year: 1882

page_text: LETTERS PATENT to John Henry Johnson of 47, Lincolns Inn Fields in the
County of Middlesex Gentleman for an invention of "IMPROVEMENTS IN
DRIVING GEAR FOR LOCOMOTIVE ENGINES" Communicated to him from
abroad by George Simpson Strong of Philadelphia Pennsylvania in the
United States of America.
i
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at the
Office of the Commissioners of Patents on the 11th July 1882.
"
JOHN HENRY JOHNSON of 47 Lincolns Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN DRIVING GEAR FOR LOCOMOTIVE ENGINES
a communication to me from abroad by George Simpson Strong of Philadelphia
Pennsylvania in the United States of America
The said Invention relates to locomotives having coupled driving wheels; and
the object of the Invention is to obviate the well known evils due to ordinary
coupling rods.
In locomotive Engines, having coupled drivers, the two driving wheels on each
side of the engine are coupled together by a rod connected to the crank pins of the
two wheels, and this coupling rod is always in a horizontal position.
Accidents frequently occur, owing to the rapid descent of the entire rod, and to
the abrupt arresting of the rod when the crank pins reach their lowest points. The
frequent breakage of coupling rods is due to the shocks and strains to. which they
are thus subjected.
This evil is obviated in the following manner: a long guide is secured at one
end to the cylinder or other suitable part of the engine the opposite end being
attached to the framework by a connection determined by the character of the said
framework.
The piston rod of the cylinder is secured to a crosshead, which is adapted to slide
upon the said guide and a second cross-head adapted to slide upon the same guide,
is connected to the first-named cross-head preferably by a rod.

page_text: A pin on the second cross-head is connected by a rod to the crank pin of one of
the driving wheels and a similar rod connects a pin on the first named crosshead to
the crank pin of the other driving wheel, so that the two driving wheels are
effectively coupled together through the medium of these two connecting rods, and
the connected and guided cross-heads, and that their unison of action is as fully
assured as if they were coupled together in the usual manner; but as one end of
each of the connecting rods is always supported and always moves in the same
horizontal course, there can be no such detrimental results of their Action as are due
to the rapid descent of an entire coupling rod, and the abrupt arresting of the same
when it reaches its lowest point.
One of the principal advantages of the invention is the facility with which it can
be applied to any existing locomotives, having coupled drivers.
It is preferred to construct the two crossheads and their connecting rod and to
adapt them to the ends of the connecting rods as follows:-
The first named crosshead consists of a T shaped piece, having a boss for receiving
the end of the piston rod, two side plates and a top plate, all being adapted to the
guide rod, which is increased in width at and near the cylinder end, the crosshead
and the side plates presenting between them two recesses, one for the reception of
the end of the rod, forming the connection to the other crosshead and the other for
the reception of one end of the rod formning the connection to one of the driving
wheels One pin serves to connect both of the rods to the said cross-head.
The rod connecting the crossheads is made Ț shaped at its outer end, and forms
the underside of the second crosshead, top and side plates completing the crosshead,
to which is connected the forked end of the rod forming the connection to the other
driving wheel.
I do not, however, desire to restrict_myself to the mode described of connecting
the two crossheads together, although I prefer it, as in my opinion the most direct
· and the simplest mode.

page_text: The cross head G consists of a T shaped piece b having a boss for receiving the
end of the piston rod a two side plates d d and a top plate e all being adapted to
the guide rod D which is increased in width at and near the cylinder end as
seen in Figures 2 and 4 the cross head and the side plates presenting between them
two recesses ff. one for the reception of the end of the rod I and the other for the
reception of one end of the rod K, one pin h serving to connect both of the rods to
the said crosshead.
The rod I is made T shaped at its outer end and forms the under side of the
cross-head H, as shewn in Figure 5, top and side plates completing the cross-head
to which is connected the forked end of the rod J.
I do not however desire to restrict myself to the mode described of connecting
the two cross-heads together although it is considered the most direct and the
simplest mode.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect I would observe in conclusion that what I consider to be novel and original
and therefore claim as the Invention secured to me by the hereinbefore in part
recited Letters Patent is :-
The combination in a locomotive of two guided cross-heads connected to each
other and to the piston rod, two driving wheels A and B and two rods one
connecting one cross head to the crank pin of one driving wheel and the other
connecting the other cross head to the crank pin of the other driving wheel all
substantially as herein before described and illustrated in the accompanying
Drawing.
In witness whereof I the said John Henry Johnson have to this my
Specification set my hand and seal the second day of January One
thousand eight hundred and eighty three.
I HENRY JOHNSON (r.g)