IMPROVEMENT OF LOCOMOTIVE AND OTHER STEAM ENGINES
Year: 1858

page_text: application for Letters Patent was not given within the time prescribed
by the Act.)
PROVISIONAL SPECIFICATION left by David Graham Hope at the Office
of the Commissioners of Patents, with his Petition, on the 27th August
1858.
I, DAVID GRAHAM HOPE, of the City of Manchester, Civil Engineer, do
hereby declare the nature of the said Invention for the "IMPROVEMENT OF
LOCOMOTIVE AND OTHER STEAM ENGINES," to be as follows:-
The portion of these improvements which relates solely to locomotives
consists in improveing the "bearing springs," whereby the constantly recurring
breakages are avoided, and a spring produced which gives seventy-five per
cent. more wear than those now in use. The "bearing springs" of a loco-
motive are usually composed of a series of steel plates piled upon each other,
and are held together by a pin passing through the centre of each plate; now
each plate is thereby weakened in the centre, where the strain is necessarily
the greatest, by the portion of metal which is drilled or punched out for the
reception of the pin. Now, this Invention is specially intended to obviate
this defect. On the under side of each of the above-mentioned plates, I raise
a cup-shaped projection, which is punched or forced out of the body of the
plate this projection, in place of weakening the plate, will strengthen it,
being upon the under or the side exposed to compression, and giving the plate
the same advantage that it would have were it made so much thicker; conse-

page_text: quently it will break anywhere else than through this point, which was
previously the weakest. In building or piling the plates upon each other to
form a spring, I commence with the top or No. 1 plate, and having cupped"
it, I take the next, or No. 2 plate, and cup it in turn, so that the projecting
part of the cup upon No. 1 plate shall fall within and fill the recess made in
No. 2 plate by forcing out the metal to form the cup. The same process is
gone through with all the subsequent plates, until the number of plates
necessary for the spring are fitted together. The spring will then consist of a
number of plates laying close together in the ordinary manner, excepting that
the top plate has a recess formed in it, and the bottom plate has a projection
which must be filed off level to permit the spring to pass within the buckle.
In the top part of the buckle a hole is drilled and tapped for the reception of
a set screw, which is screwed down into the recess formed in the top plate, by
which means the spring is prevented from moving or shifting in any way out
of the buckle.
The second part of my Invention relates to an improved construction of
piston, and is applicable to all steam engines, and a variety of other purposes
for which pistons are commonly used. It consists in a solid wrought or cast
iron body, which may or may not be formed solid with the piston rod; in a
groove, turned into this body I place a single packing ring, which differs from
all previously used in being split into two seperate parts, which I propose to
keep open or seperate as the ring wears by means of two "V pieces," which
alone are acted upon by the steam pressure within the cylinder, and not the
whole internal surface of the ring, as in all previous pistons. The advantages
are greater simplicity and less working friction.