Improvements in Steam and other Engines.
Year: 1891

page_text: Date of Application, 29th Sept., 1891
Complete Specification Left, 29th June, 1892-Accepted, 27th Aug., 1892
PROVISIONAL SPECIFICATION.
Improvements in Steam and other Engines.
I, HENRY GRAFTON, of Wardrobe Chambers, Queen Victoria Street, in the
City of London, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to improvements in high speed engines of the kind forming
the subject matter of Letters Patent granted to me dated the 11th day of
October 1888 No. 14640 in which there are two pistons working in the same
cylinder and coupled to cranks on the same shaft placed at such angular distance
apart that the pistons move for the most part in opposite directions so as to nearly
balance each other whilst their strokes are so timed that the one piston is able to
fulfil the double function of piston and of distribution valve; to wholly control the
admission and exhaust of the motive fluid, the said piston being for that purpose
formed with a trunk having a circumferential row of ports working over corre-
sponding circumferential rows of admission and exhaust ports formed in the side
of the cylinder itself.
My first improvement has for its object to more perfectly balance the working
parts, and it consists in adding a third reciprocating part of such a statical moment
and actuated at such time in regard to the movement of the steam pistons, that
the three reciprocating parts mutually balance. I may accomplish this by any
reciprocating weight, whose centre of gravity works in the line of the cylinder
axis; but, to reduce to the minimum the amount of the counterbalance required,
I preferably make a part of the cylinder in which the steam and exhaust ports are
situated, the third reciprocating part and actuate it from a pair of eccentrics
having one centre which, in the plane of rotation, is in the same relative position to
the centres of the cranks, that the crank axis is to the cranks in the unbalanced
engine when the ratio of cut-off is the same.
It is obvious that so long as the movements of the pistons and ports in regard to
each other are controlled by the same three relative centres, the cranks may be
rotated upon any axis parallel to the original axis without affecting the distribution
of steam; that the crank axis may therefore be so situated between the three
centres that the reciprocating parts actuated thereform may mutually balance and
that the angle then made by the radius-vectors of the cranks being greater,
the unbalanced weight of the parts is less than when the crank axis passes through
a point from which the ports are at a constant distance.
My second improvement has for its object to dispense with the guides for the
crosshead of the valve piston and also with the journal ends of said crosshead and
the corresponding bearings in the heads of the crosshead connecting rods. This
I effect, by making the cylinder itself the guide for the said piston which it may
well be, owing to the relatively great length of said piston and the large area of
wearing surface. The ends of the crosshead are bolted to the side connecting
rods instead of being journalled therein, as before, and in order to prevent side
binding of the piston in the cylinder consequent on the varying obliquity of the
connecting rods, the crosshead instead of being pivoted to the valve piston
by a single transverse axis as before, is pivoted thereto by a universal joint, formed
either by ball and socket or by a second axis below and at right angles to the first,
so as to permit of free oscillation of the crosshead in any direction.
Dated this 29th day of September 1891.

page_text: COMPLETE SPECIFICATION..
Improvements in Steam and other Engines.
I, HENRY GRAFTON of Wardrobe Chambers, Queen Victoria Street, in the City
of London, Engineer do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
My invention relates to improvements in high speed engines of the kind forming.
the subject matters of Letters Patent granted to me dated the 11th day of
October 1888 No. 14640 in which there are two pistons working in the samė
cylinder and coupled to cranks on the same shaft placed at such angular distance
apart that the pistons move for the most part in opposite directions so as to nearly
balance each other whilst their strokes are so timed that the one piston is able to
fulfil the double function of piston and of distribution valve, to wholly control the
admission and exhaust of the motive fluid, the said piston being for that purpose
formed with a trunk having a circumferential row of ports working over corre-
sponding circumferential rows of admission and exhaust ports formed in the side of
the cylinder itself.
My first improvement has for its object to more perfectly balance the working
parts, and it consists in adding a third reciprocating part of such a statical moment
and actuated at such time in regard to the movement of the steam pistons, that the
three reciprocating parts mutually balance. I may accomplish this by any
reciprocating weight whose centre of gravity works in the line of the cylinder
axis; but to reduce to the minimum the amount of the counter-balance required, I
preferably make a part of the cylinder in which the steam and exhaust ports are
situated, the third reciprocating part and actuate it from a pair of eccentrics having
one centre which, in the plane of rotation, is in the same relative position to the
centres of the cranks, that the crank axis is to the cranks in the unbalanced engine
when' the ratio of cut off is the same.
It is obvious that so long as the movements of the pistons and ports in regard to
each other are controlled by the same three relative centres, the cranks may be
rotated upon any axis parallel to the original axis without affecting the distribution
of steam. The crank axis may therefore be so situated between the three centres
that the reciprocating parts actuated therefrom may mutually balance and that the
angle then made by the radius-vectors of the cranks being greater, the unbalanced
weight of the parts is less than when the crank shaft axis passes through a point
from which the ports are at a constant distance.
My second improvement has for its object to dispense with the guides for
the cross head of the valve piston and also with the journal ends-of said cross head
and the corresponding bearings in the heads of the cross-head connecting rods.
This I effect by making the cylinder itself the guide for the said piston which it
may well be, owing to the relatively great length of said piston and the large area
of wearing surface on the one hand and the relatively small angular motion of the
slide rods on the other hand.
The ends of the crosshead are bolted to the side connecting rods instead of being
journaled therein as before, but the crosshead, instead of being pivoted to the valve
piston by a single transverse axis as before, is pivoted to the piston by a universal
joint formed either by a ball and socket or by a second axis below and at right
angles to the first, so as to permit of free oscillation of the crosshead in any
direction.
Reference is to be had to the accompanying drawings, forming part of this
Specification, wherein Figures 1 and 2 represent an engine embodying my first
improvement, Figure being a central vertical section in the plane of the crank
shaft and Figure 2 a central vertical section in a plane perpendicular to the crank
shaft, the said shaft being in section at one of its journals the cylinder or liner

page_text: being shewn in elevation within the fixed guide cylinder. Figures 3 to 5 illustra
my second improvement, Figure 3 being a vertical section of the valve piston in th
plane of the crosshead, Figure 4 a similar section at right angles thereto, and
Figure 5 a plan. The same letters of reference denote like parts in all the
figures.
A is the one piston acting purely as such B is the other or valve piston, C is the
reciprocating.cylinder or liner in which the pistons work as in a fixed cylinder, said
liner or cylinder reciprocating in a fixed guide cylinder C. Piston A is coupled to
the middle crank D by a connecting rod E (represented only by its centre line) and
piston B is connected to the side cranks F through connecting rods G (represented
only by their centre lines) and crosshead J pivoted to a central stem B. K are
the ports in piston B, H are the live steam ports and I the exhaust steam ports in
the reciprocating cylinder or liner C, I' and H' being annular passages in the
stationary or guide cylinder C¹ with which the ports I and H are always respectively
in communication notwithstanding the reciprocating motion of the liner cylinder.
For the purpose of imparting this motion to the said cylinder or liner C it is
connected by links and straps M jointed to the cylinder at m with the disc-shaped
crank cheeks L which act as eccentrics, but in order that the relation between the
pistons and the reciprocating cylinder or liner C necessary for the efficient action of
the piston B as distribution valve, shall be preserved the centres df of the crank
pins are in the same position relatively to centre as the centres of the cranks are
to the axis of the shaft in the partly-balanced engine before referred to, the axis n
of the crank shaft being so situated between the centres d'l that the moments of
the parts are always in equilibrium about the axis of the crank shaft.
I have represented in Figures 1 and 2 the old form of crosshead J whose ends,¹
work in guidesj in the hood of the casing. In order to dispense with these guides
and with the two journals for the connecting rods G, the crosshead J (instead of
being pivoted at J₁ to a stem B' rigidly fixed to the piston B) is pivoted at J',
Figures 3 and 4, to a 1-shaped intermediate link O, Figures 3, 4, 5, of which the
lower member forms journals O' whose axis is at right angles to the axis J¹ and
which are seated in a bearing P on the piston B. These two axes being both
diametrical to said piston and at right angles to one another, the whole constitutes
a universal joint connection between the rods G and piston B which admits of the
rods G being bolted to the ends of the crosshead J so that in operation the
✓ piece O rocking on its journals O¹ admits of the necessary angular movement of
the connecting rods, while the pivot J¹ permits of compensation for unequal wear
as before. This improvement although shewn separately for the sake of perspicuity
is intended to be applied to the engine shewn in Figures 1 and 2 as well as to the
engine described in the Specification of my previous Patent aforesaid.
It will be obvious that for two distinct axes at right angles to each other, a ball
and socket joint may be substituted, the ball being conveniently cast on the
underside of the crosshead and received in a socket in the piston.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is-
1. In the herein described engine in which two pistons connected to the same
crank shaft move for the most part in opposite directions whilst the one piston acts
also as distribution valve to wholly control the admission and exhaust, the
combination, with said pistons and their crank shaft, of a cylinder or cylindrical
liner connected with the same crank shaft so as to receive reciprocating motion
therefrom, the extent and timing of such motion with regard to the timing of
the strokes of the pistons being such that the reciprocating parts will always be
in equilibrium as specified.
2. In the herein described engine in which two pistons connected to the same
crank shaft move for the most part in opposite directions whilst the one piston acts
also as distribution valve to wholly control the admission and exhaust, the

page_text: combination, with said pistons and their crank shaft, of a cylinder or cylindrical
liner connected by links and straps with the disc-shaped cheeks which are eccentric
to the shaft journals to such an extent, and whose geometrical centre is so situated
with regard to the geometrical centres of the crank pins, that the reciprocating
parts will always be in equilibrium, as specified.
3. In an engine wherein two pistons connected to the same crank shaft move for
the most part in opposite directions whilst the one piston acts also as distribution
valve to wholly control the admission and exhaust, the combination, with the
crosshead and the valve piston, of an intermediate universal joint connecting the
two to permit of the angular motion of the connecting rods and of compensation for
unequal wear the crosshead guides being dispensed with, as described.
4. In an engine wherein two pistons connected to the same crank shaft move
for the most part in opposite directions whilst the one piston acts also as
distribution valve to wholly control the admission and exhaust, the combination
with the valve piston and the crosshead, of an intermediate 1-shaped piece, its
transverse member being journaled to the said piston to admit of the angular
movement of the connecting rods attached to the crosshead and the crosshead
being pivoted to its upright member to permit of compensation for unequal wear,
¡as described.
1000
Dated this 20th day of June 100
H. GRAFTON,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.