Note: Descriptions are shown in the official language in which they were submitted.
~ WO 95129323 . ~, ~, . 'I
2188126
IStle: ~rt ,, ~ Machinel
This invention relatcs to IC~ UlU aLi~l~; r~achines, h.,.c;~l~l referred to as
being of the kind specified, comprising a working piston and cylinder assembly,
a counter rotating crarlk drive having an inner crankshaft carrying an eccentric in
driving ~nnn~m with the piston, the eccentric being rotatable within a big end
bearing housing and the piston being connected to said bearing housing.
The machine may be, for example, an internal or ex~ernal
engine or a I , c~ ul.
GB-B-2û8û483 discloses a ~..u-u~Li--~ machine of the kind specified in
which the eccentric is connected by spaced webs to opposed journals disposed on
opposite sides of the eccentric whereby the inner crank is ~ journalled
in two outer ~ r~ which are axially aligned and are rotatably mounted
relative to a crarlkcase. The inner crankshaft has a gear associated with each
journal and engaged with a respective stationary gear.
Such a machine suffers from the 1;~ that it is necessary
accurately to align not only the axes of rotation of the two separate outer
. .~. L~ rl~ but, in additdon, the ~ 6~ between the gears associated with
the journals of the single crankshaft must be accurately ~, ' ~ L;ally mUtltallyaligned. The alignment of such relatively widely separated ~ to the
required degree of accuracy is difficult to achieve in practioe. Moreover, it isrelatively expensive to , -, . r 1,,, c such an engine, not only because of the need
to attempt to achieve such alignment, but because of the number of parts
required. rl~lLh~ lul~, the overall size of the machine in the direction of the axis
of rotation of the pair of outer ' ' ' is relatively great.
In addition, such a machme when having a single or a small number of
pistorls is prone to vibration due to out-of-balance forces and cyclic illC~ aliLi.,il.
An object of the invention is to provide a machine of the kind
specified whereby the above mentioned .l;~aJvd-lL~ are overcome or reduced.
A subsidiary object of the invention is to provide a machine of the kind specified
woss/29323 2 1 ~ 1 26
'
wherein the above mentioned additional d;a~lVdlli~ .S are overcome or are
}educed.
According to the present invention, we provide a lc~ilJIO d~ g machine of
the kind specified wherein the inner crank shaft is ~ y journalled about
an i~ axis in a single outer crankshaft which is rotatably mouMed
relative to a crank case of the machine for rotation about a main axis, the iMercrank shaft having an imler gear in ~ ~ with an outer ring gear stationary
with respect to the crank case.
The irmer and outer gears may be provided Ic~l,.,.,Li.~ with external and
internal spur or ~elical or bevel gear teeth.
The outer crankshaft may be journalled in the crank case by two bearings
disposed at positions spaced 1.,.,~ of the crankshaft and preferably
disposed on opposite sides of said externally toothed gear.
The outer crankshaft may be provided with bearing means at positions
spaced apart 1.. ~ lly thereof in which spaced apart journals of the im~er
crankshaft are rotatably mounted.
Said spaced apart journals of the inner crankshaft may be disposed on
opposite sides of said externally toothed gear.
The outer crankshaft may be provided with a cut-out to r ' the
irmer gear.
The ecceMric may be mounted in cantilever by the inner crankshaft.
The inner crankshaft may be provided with a further journal, on the
opposite side of the eccentric to the bearings whereby the inner cranlcshaft is
rotatablymountedontheoutercrankshaft,saidfurtherjournalbeingec.. ~,1.; -'l~
relative to a sub-shaft and the sub-shaft being mounted for rotation relative to the
crank case about the axis of rotation of the outer crankshaft.
The machine may have a further worlcing piston and cylinder aasembly, the
further piston being connected to a further big end bearing housing within whichsaid eCCeMric is rotatable.
Alternatively, when the inner crankshaft is provided with said further
journal rotatable relative to said sub-shaft, the machine may have a second
-
wo ssl2s323 r~
2 1 88 1 26
woricing piston and cylinder assembly, the second piston being connected to a
second big end housing within which a second eccentric is rotatable, the second
eccentric being carried by a second journai which is ~ y joumailed in a
second sub-shaft, which is rotatably mounted relative to the crani~case and by a
second further journai and wherein the further journais are each in eccentric
rotatable c :~lio..~L;~ with said sub-shaft with the respective further journais being
disposed in a ~ d angular . ~ ' ' . such as ~ oppositely
disposed.
Such a further joumai or journais may be provided if, for example, a power
take-off shaft is required at the end of the machine provided with the further
journal; or a second in-line piston and cylinder assembly is required; or two
pistons or groups of pistons, each having a ~.~ cd eccentric, are mounted
in axiai .cl ' . . for example to provide double the power input; or to couple
two machine with different functions, for example an engine and a CCIIIII.-Ie~J~.
In aii such c^qses where a further journal is provided it is not necessary to
provide a second pair of gears in qcc,.~qtir,n with the further journal.
r~ when the machine has a single or smail number of pistons it
is prone to vibration due to outer baiance forces and cydic i..c, '
a~.~i;..~;l~, to overcome this additionai problem an imner baiance weight means
may be provided to at least partly ~4 Ily balance the masses which are
rotatable about the ' axis and an outer balance weight means may be
provided to at least partly ~ balance the masses which are rotatable
about the main axis.
Preferably the imner and outer baiance weight meanS are provided so that
their respective resultant centre of gravity is co-axial with the ' axis
and the main axis .~ 4.
Accordingly, the inner cranicshaft has an inner balance weight means and
the outer crankshaft has an outer balamce weight means having its centre of
gravity radiaily opposite the resultant centre of gravity of the inner cranicshaft and
the inner balance weight means.
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~188126
The inner balance weight means may comprise firsl and second inner
balance weight means disposed on either side of the piston centre line so as to
avoid or reduce any couple around the piston centre line.
The inner balance weight means may comprise a single inner balance
weight means or a pluraliy of In~itlltii"-~lly spaced inner balance weight means.
Said pluraliy of inner balance weight means may comprise first and second
balance weight means l~ c;~ ly spaced on opposite sides of the piston or
pistons.
The single, or at least one of the, inmer balance weight means may
comprise a pluraliy of radially spaced balance weights.
The outer balance weight means may comprise a single outer balance
weight means or a pluraliy of 1~ " lly spaced outer balance weight means.
Said pluraliy of outer balance weight means may comprise first and second
outer balance weight means disposed at positions spaced apart '-~ei~ 'Iy of
the outer crankshaft.
The single, or at least one of the, outer balance weight means may
comprise a pluraliy of radially spaced balance weights.
The outer balance weight means may comprise a first and a second outer
balance weight means each having a centre of graviy disposed at positions spacedapart 1~ " lly of the outer crankshaft and disposed on radially opposite
sides thereo
The balance weight or weights which comprise the single or said pluraliy
of outer balance weight means may be disposed at any desired position or
positions l~ Iy of the axis of rotation of the outer crankshaft and/or may
be provided on an auxiliary element separate from the outer crankshaft and
arranged to rotate therewith, such as an auxiliary drive shaft.
The auxiliary element may be mounted by bearing means and provided
with a drive means so as to be driven by the outer crankshaft at the same speed
as tbe speed of rotation of the outer crankshaft.
Where the machine has a sub-shaft at least part of the outer balance
weight means may be provided thereon.
~ WO 9~/29323 2 1 8 8 t 2 6 . ~1 .
s
The outer baiance weight means may comprise first and second
y spaced outer balance weight means, the first l -~ ~C;h l ~ ly spaced
outer baiance weight means may be provided on said outer crani~shaft and the
second I ,, " '1~ spaced outer baiance weight means may be provided on said
sub-shaft.
A ~ J.u.a~ machine ~ the invention will now be described
by way of example with reference to the ~ drawings, wherein:
FIGURE 1 is a " ~ - cross-section through an internai,
engine embodying the present invention;
Fi~GURE 1_ is a r ~ cross-section showing the engine of Figure
1 in more detaii;
FIGURE 2 is a r ~ ' y ~ ''~ end view of the engine of
Figure 1;
FIGURE 3 is a ' " y cross-section through a second ~ i '
of the invention;
FIGURE 4 is a r~a~ y cross-section through a third . ' . " of
the invention;
FIGURE S is a, ' _ cross-section through a founh L - "
showing an internal . ' engine of narrow V-2 5v - .
FIGURE 6 is a ' ~ - end view of the engine of
Figure S;
FIGURE 7 is a ~' v cross sc~liundi view through a fifth
.I....I:. -: of the invention showing an engine of h~vin opposed cylinder
FIGURE 8 is a ~ cross-section showing an engine as described
with reference to Figure 7 in more detail;
FIGURE 9 is a,' ., cross-section through another ~ L
of the invention;
FIGURE 10 is a ' ~ - cross-section showing a further internai
combuston engine embodying the invention;
FIGURE lO~L shows the engine of Figure 10 in more detail;
wo9s/~s323 2 1 88 1 26
FlGURE l l is a ~ , A ",~ cross-section through a further ~ -~ ,o.l;,. ,:
of the invention;
FIGURE 12 is a ~ cross-section through a still furtber
' ~ ' of the invention;
FIGURE 12~Lshows the engine of Figure 12 in more detail;
FIGURE 13 is a ' ~ cross-section of a yet further .l.
of the invention; and
FIGURE 14 is a d;..,j. transverse cross-section of the engine of
Figure 13.
The same reference numerals have been used Lll-l "' the drawings to
refer to .,ull~-r " parts.
Referring to Figure 1, 1~Land 2, there is shown an engine which comprises
a wûrking piston and cylinder assembly ~ a piston 10 c. ;~,.u~l,l~,
within a cylinder 12 provided with a cylinder liner 14. A ~ chamber 16
is provided in . .,..~iu..~l manner.
The piston 10 is rigidly comnected to a rod 17 and is rigidly connected by
the rod to a big end bearing housing 18 and is drivingly comnected to an eccentric
20 carried on an inner crankshaft æ rotatable abûut an ' axis Y-Y.
If desired the piston 10 can be connected by a ~little end" to the rod 17 but this
is not necessary.
The inner crankshaft 22 carries f~rst and second l. ~ ly spaced imner
balance weight means which each comprise an inner balance weight 24 which are
disposed directly l ~ ' "y adjacent and on opposite sides of the eccentric 20
amd are arranged to balance the weight of the eccentric, piston bearing and
housing assembly 20, 10, 17 and 18 so that the masses rotating about the axis Y-Y
have a resultant centre of gravity which is coincident with the axis Y-Y.
The inner crankshaft æ is ~crl~ntrirslly joumalled in an outer crankshaft
26 for rotation about the axis Y-Y. The outer crankshaft 26 is itself rotatably
mounted in a crankcase 28 by main bearings 30, 32 for rotation about a main axisX-
~
W0 95129323 r~
2188126
The outcr crankshaft 26 is relatively elongated and has first and secondjournals 34, 36 which are disposed at positions which are spaced l~ of
the outer crankshaft and are engaged by the inner races of roller element
bearings which provide the main bearings 30, 32. The outcr races being received
in seats 38, 40 r~ in the crank case 28.
The outer crankshaft 26 is provided with plain bearings 41, 42 disposed in
seats 44, 46 disposed at positions which are spaced l" ~ of the outer
crankshaft 26 and are rotatably engaged with journals 48, 50 of the inner
crankshaft 22 which are spaced I ~ , apart thereof so that the eccentric
20 is mounted in cantilever by the remainder of the imner crankshaft 22.
The outer crankshaft 26 is provided with a cut-out 52 to 7! ' ''''' ''''1~l~ an
externally toothed spur or helical gear 54 fixed relative to the inner crankshaft Z
which meshes with a ~ ul l~ r " ~ internal ring gear 56 provided fixed relative
to the crank case 28. If desired bevel gear teeth may be provided.
In operation, the inner crankshaft 22 rotates about its axis Y-Y in the
opposite direction to the direction of rotation of the outer crankshaft 26 about its
a~ds X-X. The gear ratio of the externally toothed gear 54 to the ring gear 56 is
2: 1 so that the inner crankshaft 22 rotates, relative to the outer crankshaft 26,
in the opposite direction and at twice the speed to that at which the outer
crankshaft 26 rotates relative to the crankcase. The geûmetric centre of the
ecceMric 20, shown at Y-Y, IC,.;UIU~ ~ alorg a straight line indicated at A and
the piston 10 thus accurately r~,~,;,u~u~ along its respective axis.
As the - . ..,~,. and operation of a counter rotating crank drive is well
known, it will not be further described herein. Such a drive can be completely
dynanucally balanced by inner counter weight means 24 and outer balance weight
means now to be described.
Referring now to Figure 1, the outer crankshaft 26 is provided with a
flywheel 57 which carries an outer balance weight means which comprises a frst
outer balance weight means 58.
However, because of the cantilever design the balance weight means 58 is
off-set axially relative to the masses to be balanced and to avoid an out-of-balance
.
wo 9sl29323 r~ S c
2188126
couple being created the weight 58 is made larger than needed for dynalnic
balancing in a radial direction and a second outer balance weight means 60 is
provided situated loneih~ n~lly outside the bearing 30 and radially opposite thefirst outer balance weight mearls 58. Thc t,, " '- of the first and second
balance weight means 58, 60 are arranged so that the couple created by the off-
centre position of the weight 58 is L~ d for by the weight 60 and the
weights 58, 60 together ensure that the centre of gravity of the masses rotatingabout the axis X-X is coincident with the axis.
If desired, the weight 60 and/or the weight 58 may be provided in any
suitable posiion along the outer crankshaft 26. r.~ uls either or both of
the outer balance weight means 58 and 60 may be provided by a single weight or
by a plurality of weights at different angular and/or 1~ 1 positions relative
to the axis X-X so that the composite effect of the respective weight parts sumsto the desired mass and posiion.
For example, an altemative or additive position for weight 58 is indicated
at 58' in Figure 1~,
ln another example, shown in Figure 3, which is a section Ihrough an air
cooled single cylinder diesel engine having a relatively long flywheel 57, i.e. a
flywheel which is relatively long in the direction of the axis X-X, the first balarlce
weight means 58 can be mounted on the inner face of the flywheel as shown at
58" instead of, or in addition to, a weight provided at a loQtion which
LUII~:_r ' to the position of the first balance weight mearls 58' shown in Figure
1~, Of course, if a weight` is provided both at the location indicated at 58' inFigure l~and the location indicated at 58" the masses of the two weights is suchas to sum to the desired mass.
In another ex~unple, shown in Figure 4, where the flywheel 57 is formed
by the rotor of a brushless generator, the first counter weight means can be fixed
directly to a rotating canister C holding the pemmanent magnets of the brushlessgenerator (different magnet ~ul~ri5.1l~ a being shown in the top and bottom
halves of Figure 4), as shown at 58"' in Figure 4. Again the weight shown at 58"'
can be additive to or instead of the weight shown at 58 in Figure 4.
W0 95129323 r ~ 5
~J~126
In another exarnple, where the engine has a drive to a camshaft and/or an
oil pump or another auxiliary taken from the opposite end of the engine to the
normal power take-off as is also illustrated in Figures 3 and 4 at 70, an auxiliary
element or shaft ?0 is arranged to Qr y a weight 58_ which, as in the previouslydescribed examples, Qn provide tbe whole, or part of the weight required in
...... l. -~;.. with weights at least at one of the other loQtions described
,;..I,.,f~ to achieve dynamic balance of the masses rotating about Ihe axis X-
X,
Tl~e mass of the balance weight 60 is d~,t~,...,...'d so as to balance the
10't~ ' couple and is disposed radially opposite the balance weight 58, the
mass of which is increased over that necessary to radially balance the machine by
an amount equal to the mass of the weight 6Q
Correct balancing is achieved by i~ the masses (M,~) of the
piston 10, connecting rod 17 and the crank pin journal 20 with the weight 24 of
mass Mb, whereby the active radius of the parts to be balanced is the crank pin
radius "R" (c~,c.,.~..;.,;i~ of 22 and 26). The active radius of the weight 24 does not
need to be "Rn, but Qn be any length "Ln, as long as:
Mo~ ' R = Mb ' L
The axial position of the inner balance weight means 24 is preferably the
same as Mo~ For that reason the weight 24 is split and is disposed on either side
of the connecting rod. The inner crankshaft balance weight means 24 and the
oscillating masses Qn then be added up and ' on axis Y-Y which is
rotating and Qn ~herefore be balanced by the outer balance weight means as
described.
In this ~ ,. when referring to masses of the balance weight, the
effective mass at the radius of rotation of the respective centre of gravity is
referred to.
Although the present example has only a single piston, if desired, the
en0ine may be provided with more than one piston. Any crank pin positioned on
the pitch diameter of the gear 54 will describe a straight line oscillating movement
in a respective direction. Any piston mounted on such a crank or pins can be
wo ss/2s323 r ~ r
2188~26
baianced by an ~ vlJlh~le inner counter weight means 24 of a mass and position
to counteract the resultant oscillating masses. Al ~ v~,l.r, the connecting rod
17 may be extended in the ~ opposite direction to the rod 17
iilustrated and connected with another piston assembly. Of course, ~ ,.u~,.~ .,
cylinders would also be provided in all cases.
Figures 5 and 6 illustrate another "1.~ of the invention of narrow
V-2 cylinder ~"..r;~" "";,...
This engine differs from that shown in Figure 1 by virtue of being provided
witb a compound eccentric assembly having eccentrics 20 which are anguiarly
dispiaced, as shown in Figure 6, and there being a second big end bearing housing
18 associated with the second piston and cylinder assembly.
Figure 7 illustrates a further example having two opposed cy~inders and in
which a single big end housing 18 has the piston rods 17 of two pistons 10 rigidly
commected thereto. Again, of course, the piston may be pivotaily connected to the
rod 17 by a "little end" bearing.
It is to be noted that in this . L ' the first outer counter weight
means 58 is carried at the inner end of the outer cranicshaft 26 whilst the second
outer counter weight means 60 is carried by the fiywheel 57.
Figure 8 illustrates the engine shown in Figure 7 in more detail.
In this example ail the rotary bearings of the engine can be rolling element
type bearings. In particular, in this example, the bearings between the inner and
outer ~,.~lhl.~ are roller bearings 41', 42' which correspond to plain bearings
41, 42 shown in Figure l_and 2 so that the eccentric 20 is mounted in cantileverby the remainder of the inner cranksha& 22.
An additionai support for the imner crankshaft Z may be provided on the
opposite side of the or each piston if desired, for example, if a power take-off is
required at that end of the engine, or if a second in-line piston assembly is
required, or if an engine having a counter-rotating crank drive is provided in axial
aiignment to provide twice the power output, or, for example, to couple two
machines with different functions, for example an engine and a, . ~ v-.
.
W0 9~/29323 . ~
21 881 26
11
Figures 9, 10 and 10a illustrate two examples of machines having such an
additional support for the iMer crankshaft.
In any of these cases it is not necessary to provide a second pair of iMer
and outer gears, thereby avoiding the difficulty of achieving angular alignment
referred to i-..,.c...i,~..u.~.
It is necessaiy only to provide the shaft of the said opposite end with an
orbiting support by means of a sub-shaft rotatable about the axis of the outer
crankshaft and c~ ,y carrying a further journal at said opposite end of the
engine.
Figure 9 shows a four stroke in-line two cylinder engine in which tio
eccentric 20 is elongated axially and rotatably received within a second big endbearing housing of the second piston lQ At this end the eccentric 20 is providedwith a further journai 51 which is rotatably ~rc~ntrir~lly mounted in a sub-shaft
53 rotatable about the axis X-X whilst the journal 51 is rotatable about the axis
yy,
Figures 10 and 10~ illustrate another example of the invention showing a
' of the invention having two side by side piston and cylinder
. .-
One of the pistons 10 is drivingly connected to an eccentric 20 associated
with an iMer crankshaft 22 shown on the right-hand side of Figures 10 and lO~L
and is as described in CoMection with previous . ~ " except for the
provision of a further journal 109 ~cc~ntrirS~ily rotatable relative to a sub-shaft
lQ5. It may, however, be noted that the outer crankshaft 26 is provided with a
gear 120 which meshes with a further gear 120~Lto provide a power take-off drive,
for example to a cam shaft charger or generator.
The other piston 10 at the left-hand side of Figures 10 and 10_ has its big
end bearing housing 18 rotatably received on a second eccentric 20 which is
carried by a second journal 112 rotatably eccentricaliy mounted by bearings 113,114 in a second sub-shaft l lS which is rotatabiy mounted in the crankcase 28 bybearings 116, 117. The second journal 112 is u~yluvidc~i with a gear
u~ ,uu,..l;..~, to the gear 54.
wo gs/29323
2 ~ 8 8 1 2 6
12
A dividing wall 100 between the adjacent cylinders 12 has seats 101, lQ2
for taper roller bearings 103, 104 which rotatably mount the sub-shaft 105 in Ihe
wall 100. The sub-shaft 105 has a pair of generally cylindrical passages 106, 107
the centres of which are disposed on a diametral plane of the shaft 105 and on
opposite sides of the centre 108 thereof. The passage 106 receives the further
joumal 109 projecting from the inner crankshaft æ associated with one of the
cylinders 12 whilst the other passage 107 receives a second further journal 110
projecting from the inner secorld eccentric 20 of the other piston lQ The further
joumals 109,110 are thus each in eccentric rotatable .~I..liu.~ with said sub-
shaft 105 with respective journals being disposed in a !"~.1. ~. ,..: d angular
iUl.allil. such as ~ opposite.
Accordingly, firing and inertia loads from the respective inner cranks are
supported by the relatively large bearings 103, 104 which support the common
further sub-shaft 105 with which the further joumals 109, 110 are engaged.
Because of torque loads the inner crankshaft is provided with a small support
bearing at the drive end as shown at 41.
Figure 11 illustrates another example of the invention where it is desired
to provide a generator and charger facility. In this case, if a sub-shaft is provided
on the opposite side of the piston or pistons, the flywheel 57 is preferably
mounted on the side of the engine provided with the inter-engaging gears 54, 56
to avoid high loads on the " bearings 41, 42 due to torque ''
To make the best use of the available space the flywheel 57 should
preferably be of generally can shape, as illustrated in Figure 11 and in other
Figures. Accordingly the generally cylindrical wall 57_ of the flywheel may
contain a pemmanent ring magnet 130 with any desired number of poles. A
stationary ammature 131 may be mounted inside the ring to create an integrated
brushless generator which may match the full power output of the engine. As the
electrical energy generated is a proportion to the peripheral speed of the magnet
ring and to avoid oversizing the flywheel flux ring, an epicyclic gearbox may beprovided between the engine output shaft and the flux ring to increase the speedof rotation of the latter. Such an e .,ll, " is illustrated in Figure 12 and 12~
~ WO 95129323 2 1 8 8 l 2 6 f `'~
13
An epicyclic Bear box 80 comprising a sun gear 81, planet gears 82 and an
annulus 83 is provided to increase the output speed from the engine and the
space around a tubular bearing extension 84 is used to house a brushless
generator 85 provided on a drum 86 keyed to the shaft of the sun gear 81.
The f~ywheel illustrated in Figures 12 and 12~ may carry a further gear
drive to drive a high speed coupled charger as is required for two stroke
operation.
Referring now to Figures 13 and 14 there is illustrated a two stroke
opposed cylinder ~ ~ with a charging piston.
The opposed pistons 10 are drivingly connected to an eccentric 20 carried
by an inner crankshaft 22 as described ~ . The inner crankshaft 22 has
a further eccentric 140 at the same radius as the axis of rotation Y-Y as the
eccentric 20 but angularly offset therefrom and drivingly comnected by a furtherbearing housing 141 to a piston rod 14~ of a charging piston 144 slidable in a
cylinder 145. The cylinder 145 is provided at oae end with an inlet valve 146 and
an outlet valve 147 whilst at its other end it has an inlet valve 148 and an outlet
valve 149. The outlet valve 147 is connected, via a first plenum chamber 150 to
the interior of the cylinder 12 associated with one of the pistons 10 via an inlset
valve 151 whilst the outlet Yalve 149 is connected via a second plenum chamber
152 to the interior of the cylinder 12 of the other piston 10 via a second inletvalve 153. Accordingly, as the pistons 10 ~.,;~ . so does the charging piston
to alternately charge the working cylinders 12. The engine is also provided withan oil sump 154 and with exhaust valves 155 for the cylinders 12 in: ..
malmer.
The plenum chambers 150, læ are provided to take care of the 90 phase
angle between the charging and working pistons but at high engine speeds these
may not be required.
Although in some of the previously described, . ~".1:.,. !~ plain bearings
have been described as being provided between the inner and outer rr~nl~h~frc
if desired rolling element bearings may be provided ~
wo 9s/29323
218812~
14
Although all the illustrated examples are internal . b~ engines the
invention and the structural features described arld illustrated herein can be
applied to other ~ ,;,UlU~.Uly machines such as an external b~ engine
or a . A C aaul or pump.
In all ~ , although only a single pair of inter-engaged immer arld
outer gears 54, 56 are illustrated, if desired a plurality of axially spaced pairS of
irlter-engaged inner and outer gears may be provided rotatable with the single
inner crankshaft 22 on one axial side only of the piston or pistons. Such singlepair or said plurality of pairs of geara provide a single pair of inter-engaged inrler
and outer gear means.
If desired, a machine may comprise a plurality of l~.~,;,u~u~l;-~ machines
embodying the invention.
The features disclosed in the foregoing description, or the following claims,
or the acw~ drawings, expressed in their specific forms or in the terms
or means for p ~.,." .~,5 the desired function, or a methûd or process for
attaining the disclosed result, may, separately or in any . ' of such
features, be utilised for realising the invention in diverse forms thereof.
