Year: 1887

page_text: Date of Application, 27th May, 1887
Complete Left, 25th Feb., 1888
Complete Accepted, 11th May, 1888
I, CHARLES HORACE BENTON of Victoria Mansions, Victoria Street, London, S.W.,
Engineer, do hereby declare the nature of this invention to be as follows:-
My improvement is intended to obviate the wear and tear of the reciprocating parts
and their connections consequent upon driving a double acting steam or other recipro-
cating engine at a high speed, I accomplish this by the prevention of the reversal of
strains in the reciprocating parts when the crank passes the dead points and by the
prevention of the reversal of strains just before the crank reaches the dead points by
absorbing or by counteracting the momentum of the said reciprocating parts. My
improvement consists of employing two systems of reciprocating parts attached to the
same crank. One system communicates the impulses of the motive fluid in one
direction, the other system in the contrary direction. The systems work together as a
single double acting piston as far as the distribution of the motive fluid is concerned,
but they have a slight relative movement, and, not being rigidly fixed together as far
as the strains are concerned they act as a double system. I make the piston head in
two parts, to one of these parts I attach a hollow piston rod and to each side of the
hollow piston rod a connecting rod joined to the crank pin. To the other part of the
piston head I attach a piston rod which has a slight longitudinal movement through
the hollow piston rod. To the piston rod within the hollow piston rod I attach a con-
necting rod which is joined to the crank between the two other connecting rods
Each part of this double piston is therefore exposed to the pressure of steam in one
direction only. The strains caused by this pressure are always in the same direction,
and not alternately reversed as in the ordinary double acting engine, the out stroke
being caused by one half of the piston and its appropriate connections, the in stroke
being caused by the opposite part of the piston and its appropriate connections.

page_text: To keep the strains in the same direction at the end of the stroke so as not to be
reversed by momentum I employ auxiliary cylinders, in which work pistons rigidly
attached to the two sets of reciprocating parts. These pistons compress some elastic
fluid upon the return stroke of the set of reciprocating parts to which they are
attached, or the two sets of reciprocating parts may have attachments which are sub-
ject to permanent pressure against the return stroke, said pressure on this return
stroke serving to counterbalance the momentum.
To facilitate starting the engine I employ some stop cock placed in the auxiliary
cylinders so as to let the fluid compressed therein escape during the first few strokes,
or, if permanent pressure is used I arrange a valve or mechanism to remove this
pressure during the first few strokes.

page_text: Improvements in High Speed Steam and other Engines.
I, CHARLES HORACE BENTON, of 2 Victoria Mansions, Victoria Street, London, S. W.,
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 improvement is intended to obviate the wear and tear of the reciprocating parts
and their connections consequent upon driving a double acting steam or other fluid
pressure reciprocating engine at a high speed. I accomplish this by the prevention
of the reversal of strains in the reciprocating parts when the crank passes the dead
points and by the prevention of the reversal of strains before the crank reaches the
dead points by absorbing or by counter-acting the momentum of the said reciprocating
parts. My improvement consists of employing two systems of reciprocating parts
attached to the same crank. One system communicates the impulses of the motive
fluid in one direction, the other system in the opposite direction. The systems, which
thus form two sets of reciprocating parts, work together as a single double acting
engine as far as the distribution of the motive fluid is concerned, but they can have a
slight relative movement, and, not being rigidly fixed together, as far as the strains
are concerned, they work as two single acting engines.
As the double system of parts makes the weights which must be started and brought
to rest on each stroke comparatively large, it is important to provide means, other than
the compression of steam just at the end of the stroke, to bring part of this moving
mass to rest and to regulate the momentum acquired during the first part of the stroke
so that the pressure on the bearings of the engine shall be less and so that no reversal
of strains can occur from the momentum just after the mid point of the return stroke
is passed. To effect this I employ auxiliary cylinders in which work pistons rigidly
attached to the two sets of reciprocating parts. These pistons compress some elastic
fluid upon the return stroke of the set of reciprocating parts to which they are attached,
or, the two sets of reciprocating parts may have attachments which are subject to
pressure constantly against the return stroke, said pressure on the return stroke serving
to counteract the momentum. In this case the crank must not only overcome the
inertia of the moving parts on the return stroke as in ordinary single acting engines
but must also overcome the constant pressure against the return stroke.
To facilitate starting the engine before such a speed has been attained as to produce
the momentum thus arranged for, valves may be placed in the auxiliary cylinders so
as to let the fluid compressed therein escape during the first few strokes, or, if pressure
constantly in one direction is used a valve or mechanism to remove this pressure during
the first few strokes may be provided.
**4.1 Di

page_text: DESCRIPTION OF DRAWING.
One arrangement is illustrated by Figure 1 of the annexed drawing. This is a
plan, partly in section, of a horizontal steam engine. The valve gear and other details
not peculiar to my invention are not shown. I make the piston head in two parts 6
and 7. To one of these parts 7 is attached a hollow piston rod 9 and to each side of
the hollow piston rod by means of a cross-head 14 is attached a connecting rod in two
parts 17 and 171 joined to the crank 20. To the other part 6 of the piston head is
attached a piston rod 8 which is joined to the crank 20 by means of a second cross-
head 15 and a second connecting rod 18. The piston rod 8 passes through the part 6
of the piston and through the hollow piston rod 9. The steam which is admitted
through the port 10 transmits its power to the crank by causing a state of tension in
the part 7 of the piston and its respective connections and the steam admitted through
the port 5 transmits its power by causing a state of thrust in the part 6 of the piston
and its connections. The engine is therefore double acting, but no reversal of strains
takes place due to the alternating pressure of the steam of opposite sides of a single
solid piston as in ordinary double acting engines. The parts 6 and 7 of the piston
are separated sufficiently_to allow for wear of the brasses and no knock can arise from
this cause as any wear is taken up automatically by a slight longitudinal movement of
one set of parts relatively to the other set of parts. As the wear of the crank on the
connecting rod 17 and 17¹ is always on the outer side the connecting rod ends need
only have brasses on the outer side as shown by the position of the adjustment keys 21
and 21. In the same way the connecting rod 18 need have brasses only on the inner
side as shown by the key 19. As the cross-head 15 has the same general position and
motion as the cross-head 14, and, it is only necessary to provide for sufficient relative
sliding to allow for the wear of the brasses and pins, in this arrangement the cross-
head 15 is placed within the cross-head 14, the angular thrust of the connecting rod 18
being taken by the hollow piston rod 9.
Fixed to the part 6 of the piston is a plunger 3 which works in the auxiliary
cylinder 1. This auxiliary cylinder has ports 4 which communicate with the atmo-
sphere. On the outward stroke the part 6 of the piston and its respective connections
are kept in thrust by the pressure of the steam, on the return stroke they are kept in
thrust at first by the inertia of their weight but just after the middle of the stroke is
passed the momentum acquired begins to be given off and the state of thrust would
be changed to tension were it not that at this point the end of the plunger 3 closes the
ports 4 and thereafter compresses the air in the auxiliary cylinder 1, thus maintaining
the state of thrust in the part 6 of the piston and its connections throughout the return
stroke. The end of the auxiliary cylinder has a port 2 fitted with a valve to open at
the starting of the engine. The ports 4 may connect with any elastic fluid such as
the exhaust steam or boiler steam, or, these ports may be closed and pressure applied
in the form of a spring interposed between the plunger 3 and the end of the auxiliary
cylinder 1 or the port 2 may connect with the boiler and steam be constantly admitted
to the top of the plunger. In the case of such constant steam pressure the port 2 may
be fitted with a valve to shut off the steam at the starting of the engine, as the crank
on the return stroke would not only have to accelerate the reciprocating parts but also
overcome the constant steam pressure. The cross-head 14 is made cylindrical and is
provided with a piston 11 working in an auxiliary cylinder 12 and serving to keep the
part 7 of the piston and its connections in a state of tension, but in other respects is
in every way analogous to the plunger 3 and the auxiliary cylinder 1, the ports 13
and 16 corresponding with the ports 4 and 2 respectively.
Figure 2 represents an engine made according to my invention but with certain
modifications in its details and so arranged as to produce a compound engine. Similar
parts have the same members as in Figure 1. The part 7 of the piston is here made
with a considerably smaller effective area than the part 6 of the piston, the valve being
so arranged that the steam passes from the boiler to the high pressure side of the piston
and is then transferred to the low pressure side of the piston. The high pressure part

page_text: of the piston and its respective reciprocating connections does not in this case require
additional means to keep the strains from reversing upon the return stroke as the
valve may be so arranged as to cut off steam from the low pressure part of the piston
before the final exhaust pressure is reached. The pressure on the high pressure part
of the piston will therefore never fall below the cut off pressure on the low pressure
part of the piston and the point of cut off may be so arranged as to keep sufficient
pressure on the part 7 of the piston so that the strains in it and its connections will
not be reversed at any point of the return stroke. The part 7 of the piston thus
acting on the return stroke the same as if it were an attachment working in an
auxiliary cylinder with constantly admitted steam pressure as before described. The
low pressure part of the piston must however have the plunger 3 and an auxiliary
cylinder 1 as shown, since as the momentum acquired in the first part of the return
stroke begins to be given off just after the mid point of the stroke is passed the closing
of the exhaust at this early point would be ineffective in the case of a condenser and
would give too great a compression at the end of the stroke in the case of an atmo-
spheric exhaust.
The piston rod 9 instead of being tubular and entirely enclosing the other piston
rod 8 here consists of two solid rods passing through the part 7 of the piston and
working on opposite sides of the rod 8, each of the rods 9 being joined to the con-
necting rods 17 and 17' by the cross-head 14 and 14. The cross-head 15 here
communicates the angular motion of the connecting rod to the engine frame through
the gland of the cylinder as in an ordinary trunk engine.
Having now particularly described and assertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
1. An engine having its reciprocating parts, piston, piston rod, cross-head and
connecting rod in two sets, both on the same side of crank, one of which sets transmits
the fluid pressure in one direction and the other set in the opposite direction to the
crank of a crank shaft substantially as described.
2. An engine having its reciprocating parts, piston, and piston rod, cross-head and
connecting rod in two sets, one of which sets transmits the fluid pressure in one
direction and the other set in the opposite direction to the crank of a crank shaft and
having the piston rod or rods of one set working through the piston of the other set,,
substantially as described.
3. An engine having its reciprocating parts, piston, piston rod, cross-head and
connecting rod in two sets both on same side of crank, one of which sets transmits
the fluid pressure in one direction and the other set in the contrary direction to the
crank of a crank shaft and having auxiliary attachments to regulate the momentum
substantially as described.
4. An engine having its reciprocating parts, piston, piston rod, cross-head and
connecting rod in two sets, one of which sets transmits power in one direction and the
other set in the opposite direction to the crank of a crank shaft and having one piston
of smaller effective area subject to pressure in one direction throughout both recipro-
cations and the other piston having an auxiliary attachment to regulate the momentum
substantially as described.
5. My improvements in steam engines substantially as described and illustrated in
the annexed drawings.