IMPROVE- MENTS IN STEAm and PheunATIC ENGINES
Year: 1871

page_text: LETTERS PATENT to John Darlington, of No. 2, Coleman Street
Buildings, in the City of London, for the Invention of "IMPROVE-
MENTS IN STEAm and PheunATIC ENGINES.”
Sealed the 3rd April 1872, and dated the 7th October 1871.
PROVISIONAL SPECIFICATION left by the said John Darlington at
the Office of the Commissioners of Patents, with his Petition, on
the 7th October 1871.
I, JOHN DARLINGTON, of No. 2, Coleman Street Buildings, in the City
of London, do hereby declare the nature of the said Invention for
“IMPROVEMENTS IN STEAM AND PNEUMATIC ENGINES," to be as follows:-
My improvements in steam and pneumatic engines consist essentially
of a cylinder, valve chamber, piston, piston rod, and a circular faced
slide valve. The piston partially fills the cylinder, and is rendered
steam or air tight by means of clastic rings or recesses formed on the
cylindrical part of the piston. In the same manner the piston rod is

page_text: rendered air or steam tight in passing through the cover of the cylinder.
A valve bar slightly twisted, or a bar furnished with a slot or feather
slightly out of line with the longitudinal axis of the bar, passes into
the piston and piston rod. The upper part of this valve bar also passes
through a division in the cylinder into a valve chamber, and carries a t
tappet for shifting a circular faced slide valve.
When it is necessary for the piston rod to impart a rotary motion
a bar and ratchet and wheel are placed within the piston rod, and the
valve bar is in this case sufficiently lengthened to effect the object.
The reciprocating movement of the piston is effected by admitting 1
steam or air to the valve chamber and inferior area of the piston, and
by a valvular admission and exhaustion of air or steam to and from the
opposite side of the piston.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Darlington in the Great Seal Patent Office
on the 3rd April 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
DARLINGTON, of No. 2, Coleman Street Buildings, in the City of
London, send grecting.
'
WJEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent bearing date the Seventh day of October, in the year of
our Lord One thousand eight hundred and seventy-one, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said John Darlington, Her special
licence that I, the said John Darlington, my executors, administrators,
and assigns, or "such others as I, the said John Darlington, my
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 STEAM AND PNEUMATIC ENGINES," upon the condition

page_text: .
(amongst others) that 1, the said John Darlington, my executors or
administrators, by an instrument in writing under my, 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 I, the said John Darlington, do hereby
declare the nature of my 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 accom-
panying Drawings, and to the letters and figures marked thereon, that is
to say :-
My improvements in steam and pneumatic engines consist essentially
of a cylinder, valve chamber, piston, piston rod, and a circular fuced
slide valve. The piston partially fills the cylinder, and is rendered
steam or air tight by means of elastic rings or grooves formed in the
outer circular part of the piston. In the same manner the piston rod is
rendered air or steam tight in passing through the cover of the cylinder.
A square or polygonal valve bar slightly twisted, or a round bar having
one groove or several grooves, or a single feather or several feathers,
passing in a slightly spiral direction along a convenient portion of its
length, passes into the piston and piston rod. The upper part of this
valve bar passes through a division in the cylinder at right angles with
the longitudinal axis of the cylinder into a valve chamber, and carries
a tappet or fork for shifting a circular faced slide valve.
When it is intended that the piston and piston rod shall impart a
turning motion, as in the case of rock boring, a ratchet wheel is fitted
to the turning bar and within this ratchet wheel is placed a turning nut
fitted with pawls and springs, the whole apparatus being placed in the
interior of the piston rod, as shown on the annexed Drawings. Under
such circumstances the valve bar must be of sufficient length to effect
the movement of the turning bar.
The mrminusanting masamant of the mintan is affected by admission

page_text: piston. The movement of the piston is effected by alternately admitting
and discharging steam or compressed air to and from the upper end of
the piston, the area of which is considerably greater than that of the
lower end.
The chief novel action of the machine under consideration is as
follows: The valve and valve bar being adjusted in a manner suitable
to the contemplated working of the machine, and then the steam or air
admitted to the valve chamber, it follows that as the valve bar is slightly
twisted in. the manner hercin-before described, and as the said bar
passes through the centre of the piston, the direct reciprocating action
of the piston will cause a simultaneous reciprocating action from right
to left and from left to right of the valve bar, and therefore of the valve
attached to or otherwise in relation with its end, thus effecting the
alternate opening and closing of the steam and exhaust ways. This
action of the valve bar, seeing that the bar passes through the centre
of the turning nut, will, with the aid of the pawls and springs, suffice
to turn the ratchet nut K and rotary bar H in one direction, the clicks
or pawls of such wheel slipping over the ratchet teeth in the contrary
direction.
The details of the turning nut and ratchet wheel are shown in Figs.
3, 4, 5, and 6, in which Fig. 3 represents an elevation, and Fig. 4 an
end view of turning nut; and Fig. 5 a section, and Fig. 6 an end view
of the ratchet wheel.
•
When a turning or boring action is not needed the turning nut L,
5 ratchet wheel K, turning bar H, and stay bar S are dispensed with.
The piston rod is then made solid, and the end of the rod furnished
with such a connection as may be necessary for the work to be
performed.
Having thus described the nature of my said Invention, and the
O manner in which the same may be carried into effect, I now observe in
conclusion that I do not confine myself to the precise details or
arrangements which I have had occasion to describe, as many variations
may be made therefrom without deviating from the main features of my
Invention; but what I consider to be novel and original, and there-
5 fore claim, is_
The peculiar combination, arrangement, and adaptation of a slide bar

page_text: and circular faced slide valve in and to steam and pneumatic engines
for rock drilling, stamping, riveting, tool sharpening, winding, pumping,
and stone dressing, with or without a turning bar fixed within the piston
rod, substantially as herein-before described.
In witness whereof, I, the said John Darlington, have hereunto 5
set my hand and seal, this Second day of April, in the year
of our Lord One thousand eight hundred and seventy-two.