Improvements in the Construction of Self-lubricating Steam Engines.
Year: 1898

page_text: Date of Application, 26th Mar., 1898
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Date of Application, 26th Mar., 1898
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Improvements in the Construction of Self-lubricating Steam
Engines.
We, GEORGE HARRISON SHEFFIELD, Civil Engineer, and JAMES DENIS
TWINBERROW, Civil Engineer, both of 13, Mosley Street, Newcastle-upon-Tyne,
do hereby declare the nature of this invention to be as follows:-
This invention comprises an arrangement of parts with the object of reducing
vibration, of giving a better control over the distributing valves, and of apply-
ing and regulating the supply of lubricant to the bearings. It is applicable
mainly to the inverted enclosed type of high speed engine, but may be modified
to suit any ordinary known arrangement.
We form chambers for the working valves, steam chests and receivers in the
cylinder covers, in order to secure the shortest possible ports with minimum
clearance surfaces; the cylinder castings are plain and uniform to facilitate
manufacturers in hard metal, and to obviate distortion when expanded by heat.
When placed side by side their centres are sufficiently close to enable us to dis-
pense with intermediate bearings on the crank shaft, and when the moving parts
are of equal weight the vibrating moment is less than one half of that in engines
of similar class with a distributing valve between the cylinders.
We prefer to place the cylinders of engines of about 200 H.P. and upwards,
at different levels, so that their centres may be kept as close as possible by
recessing the high pressure cylinder beneath the lower cover of the low pressure
cylinder.
We eliminate the vibrating couple due to the equal revolving masses at the
crank pins by equivalent reduced counterweights attached to the outer crank
webs, to the fly wheel and governor disc, or to other points on the crank shaft.
The reciprocating parts attached to each piston may be of equal weight as in
the ordinary practice, but in order to eliminate the vertical couple due to this
arrangement and to obviate the addition of needless weight to the smaller piston,
we sometimes balance the low pressure parts by the similar lighter parts of the
high pressure motion on one side and by an equivalent counter weight or bob
weight suitably placed on the other side.
In arranging an engine with three cylinders, we balance the parts by placing
the central crank diametrically opposite to the outer cranks, and make ats
attached parts equal to the combined weight of the parts attached to the outer
cranks.
We operate the valves by means of crown cams running in contact with rollers:
in order that the velocity of rotation of the latter may remain constant, the
contact surfaces are portions of cones with a common apex. A cam fixed to
the driving shaft gives a constant motion controlling the pre-admission, exhaust,
and compression, but the extent and duration of the opening to steam are con-
trolled by a cam surrounding the fixed cam, guided to move around same in a

page_text: helical direction when partially rotated by the governor. The friction of the
helical guide may be reduced by means of rollers between the surfaces. The
space between the inner and outer cams forms a dashpot. When the same valve
is employed to control the admission and exhaust, the roller operating it is
sufficiently long to bear on the face of either or both cams, but if a separate
cut off valve is employed it must be worked from a roller bearing on the outer
cam only.
In the case of large engines we prefer to make the steam and exhaust valves
entirely separate, and to operate them from a shaft driven at right angles to
the crank shaft by means of skew gearing: the steam valves alone are then
controlled by a shaft governor.
The main bearings, connecting rod bearings, and crosshead slides are lubri-
cated by oil delivered to them under pressure by means of pumps, one of which
is provided for each line of motion. The plunger is tubular and is fixed to a
convenient point on the crosshead, whilst the barrel is connected to a foot valve,
and by means of a delivery pipe, to the main bearing. There are no delivery
valves, the film around the surfaces preventing the return of air. From the
head of the plunger a small branch leads to the bearing surfaces on the cross-
head, whilst a central hole communicates with the gudgeon pins which are
preferably integral with the crosshead, and are provided with bushes having
closed ends. The connecting rod in which the bushes are fixed is made in two
parts, united by the big end cap and by a brace beneath the crosshead, which
also forms an abutment for the piston rod nut when the latter is slacked back
to withdraw the rod; one or both of the bushes is connected by a pipe to the big
end brasses.
In order to regulate the amount and pressure of the oil delivered, the suctions
of both pumps are connected by a branch containing a regulating valve; when
the valve is closed. the pumps act independently and deliver their full volume at
each stroke; when the valve is fully open the suction stroke of one pump is prin-
cipally supplied by the delivery from the other pump; but owing to the angularity
of the connecting rods, when the cranks are at half stroke both plungers are
below their mid position and hence give a positive delivery, the suction occur-
ring as the cranks approach the dead points.
By regulating the connecting valve the quantity of oil drawn into the system
at each revolution may be varied from about one tenth to the full volume of the
plunger displacement."
Dated this 25th day of March 1908
G. H. SHEFFIELD.
J. D. TWINBERROW.
Improvements in the Construction of Self-lubricating Steam
Engines.
We, GEORGE HARRISON SHEFFIELD, and JAMES DENIS TWINBERROW, both of 13,
Moseley Street, Newcastle-on-Tyne, Engineers, 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:-
This invention relates to improvements in the construction of self-lubricating
steam engines, our objects being to reduce vibration and to provide for the better
control of the distributing valves and of the supply of lubricant to the bearings,

page_text: can be adapted to engines of varying types but is especially
applicable to high speed engines of the inverted and enclosed type.
In the three accompanying sheets of explanatory drawings to be hereinafter
referred to:-
Figure 1 is a sectional front elevation and Figure 2 an end elevation, with
part in section, of a compound engine having our invention applied thereto.
Figure 3 is an end elevation of the governor, and Figure 4 a sectional front
elevation of the governor and of the valve operating cams.
Figure 5 is an end view of the valve operating cams and rollers, and Figure 6
an end view showing the face of 'the wrist plate and the interposing ring or
collar which is arranged between the wrist plate and the valve operating cams.
The same reference letters in the different views indicate the same parts.
We form chambers for the working valves, steam chests, and receivers, in
the cylinder covers, as illustrated, in order to secure the shortest possible ports
with minimum clearance surfaces; the cylinder castings are plain and uniform
to facilitate manufacture in hard metal and to obviate distortion when expanded
by heat. When placed side by side their centres are sufficiently close to enable
us to dispense with intermediate bearings on the crank shaft A, and when the
moving parts are of equal weight the vibrating moment is less than one half
of that in engines of similar class with a distributing valve between the cylinders.
We prefer to place the cylinders of engines about 200 H.P. and upwards, at
different levels, so that their centres may be kept as close as possible by reces-
sing the high-pressure cylinder beneath the lower cover of the low-pressure
cylinder.
We eliminate the vibrating couple due to the equal revolving masses at the
crank pins by equivalent reduced counterweights attached to the outer crank
webs, to the Hy wheel and governor disc, or to other points on the crank shaft.
The reciprocating parts attached to each piston may be of equal weight as in
the ordinary practice, but in order to eliminate the vertical couple due to this
arrangement and to obviate the addition of needless weight to the smaller piston,
we sometimes balance the low-pressure parts by the similar lighter parts of the
high-pressure motion on one side and by an equivalent counterweight or bob
weight suitably placed on the other side.
In arranging an engine with three cylinders, we balance the parts by placing
the central crank diametrically opposite to the outer cranks, and make its attached
parts equal to the combined weight of the parts attached to the outer cranks.
We operate the valves by means of crown cams running in contact with rollers,
and in order that the velocity of rotation of the latter may remain constant the
contact surfaces are portions of cones with a common apex. Referring to the
drawings, the cam B fixed to the crank shaft A gives a constant motion con-
trolling the pre-admission, exhaust, and compression, but the extent and dura-
tion of the opening to steam are controlled by a cam C surrounding the fixed
cam B and caused to move around the same in a helical direction when partially
rotated by the governor arranged within the fly wheel disc D. The governor
mechanism, comprises the hinged weights and El respectively connected by
rods with the springs F and F as illustrated, the springs being so arranged that
the centrifugal force of the revolving hinged weights E and E¹ will act against
and tend to compress them. The hinged governor weights E and E are also
connected with the wrist plate G and adjacent to the outer end or face of such
plate we fix on the shaft or governor boss a guide G¹ having a face with a helical
configuration corresponding with the like configuration of the adjacent end or
face of the cam C. (The cam C is connected with the wrist plate G by the driv-
ing projections or pins C, and as the independent rotary movement imparted
to the wrist plate by the action of the governor is thus transmitted to the cam C,
the said cam is caused to slide or reciprocate through a short distance, by the
movement of the helical face of the cam C relatively to the similar fage of the

page_text: guide G¹, for the automatic variation of the point of cut off in accordance with
the work required from the engine. The space as b between the inner and outer
cams B and C forms a dashpot. We preferably employ anti-friction rollers as h
mounted on a ring or collar as H arranged between the adjacent helical faces
of the guide G¹ and outer cam C respectively.
The rollers as J for running in contact with the crown cams B and C are
mounted on levers as J' on the rocking shaft K. By levers K' also mounted on the
rocking shaft K, the required motion is transmitted to the valves to be operated
as shown at Figure 1. When the same valve is employed to control the admis-
sion and exhaust, as in the case of the engine shown in the figures, the roller
but if a
operating it is made long enough to bear on the face of both cams;
separate cut off valve is employed it must be worked by a roller bearing on the
outer cam only.
In the case of large engines we prefer to make the steam and exhaust valves
entirely separate, and to operate them from a shaft driven at right angles to
the crank shaft by means of skew gearing; the steam valves alone are then
controlled by a shaft governor.
The main bearings, connecting rod bearings, and crosshead slides are lubri-
cated by oil delivered to them under pressure by means of pumps as L, one of
which is provided for each line of motion. The plungers L' of the pumps are
-tubular and they are secured to the cross-heads M M¹ respectively, whilst the
pump barrels are connected by piping to the foot valves as N Ni respectively
and with the bearings to be lubricated. The suction pipes are shown in
full at Figure 1 but the remainder of the piping is indicated by the thick
single lines as 12. We employ no delivery valves, the film of oil around the sur-
faces of the bearings preventing the return of air. From the head of each
tubular plunger a small branch passage leads to the bearing surfaces of the
crosshead and the cross-head guide as m. (Figure 2), whilst another passage
communicates with the gudgeon pins which are preferably integral with the
cross-head and are provided with bushes having closed ends. Each connecting
rod, having the bushes 0 0' fitted therein, is made in two parts united by the big
end cap and by a brace as m² m² beneath the cross-heads; such braces also form
an abutment for the piston rod nuts when the latter are slacked back to with-
draw the rods. The bushes 0 0¹ are connected by a pipe to the big end brasses.
In order to regulate the amount and pressure of the oil delivered, the suctions
of both pumps are connected by a branch containing a regulating valve P
When the valve is closed the pumps act independently and deliver their full
volume at each stroke; when the valve is fully open the suction stroke of one
pump is principally supplied by the delivery from the other pump, but owing
to the angularity of the connecting rods when the cranks are at half stroke
both plungers are below their mid position and hence give a positive delivery,
the suction occurring as the cranks approach the dead points. By regulating
the valve P the quantity of oil drawn into the system at each revolution may
be varied from about one-tenth to the full volume of the plunger displacement.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:
1. In steam engines the improved arrangement and combination of parts for
reducing vibration, controlling the distributing valves, and applying and regulat
ing the supply of lubricant to the bearings, substantially as described.
2. In steam engines, the combination with the valve linkage, of operating
cams having the one surrounding the other, the outer cam being arranged fo
reciprocating through a short distance relatively to the inner cam, substantially
as and for the purpose described and as illustrated.
3. In steam engines, the combination comprising a pair of valve operating
cams arranged the one within the other, the inner cam being secured to th

page_text: shaft whilst the outer cam is free on the shaft and in connection with the
governor, substantially as and for the purpose described and as illustrated.
4. In steam engines, the combination with the crossheads of single acting
lubricating pumps and connections arranged substantially as described and as
illustrated.
5. A self-lubricating steam engine constructed and arranged substantially as
described and as illustrated.
MARKS & CLERK,
18, Southampton Buildings, London, W.C., and
13, Temple Street, Birmingham, Agents for the Applicants.