AN IMPROVED HYDRAULIC CRANK WITH VARIABLE ECCENTRIC MOTION
Year: 1883

page_text: LETTERS PATENT to Jules Charles Müller, Mechanical Engineer of the city
of Paris in the Republic of France for an Invention of AN IMPROVED
COMPLETE SPECIFICATION filed by the said Jules Charles Müller at the
Office of the Commissioners of Patents on the 9th June 1883.
JULES CHARLES MÜLLER Mechanical Engineer of the city of Paris in the
Republic of France AN IMPROVED HYDRAULIC CRANK WITH VARIABLE ECCENTRIC
MOTION
The hydraulic crank the subject of the present invention is sui generis, whether
structurally or functionally considered, its eccentric radius may be varied in length
and direction, such variations being capable of regulation either near at hand or at
a distance, whilst in motion or at rest.
In all cases where it is advantageous to regulate from a distance the various
positions of a centre or point of rotation, whether it be a crank at full stroke, and
the eccentric pin is to be drawn from or nearer to the axis, or even on it, whether
it be a crank at partial stroke or throw, or an eccentric whose eccentricity is to be
increased, reduced or centralized, the centre must be passed so as to reverse the
eccentric motion.
Ordinary mechanical means such as levers, shafts, rods, gear work, pulleys
and so forth do not admit of a simple solution of this proposition which can only
be so solved by the use of the hydraulic crank whose object is as follows: to keep
the eccentric moving in its several positions relatively with the axis between two
liquid blocks contained in a cylinder, on the two faces or surfaces of a piston, the
total volume of these two blocks is constant, but the two partial volumes may vary
under the influence of a distributer or regulator.
According to convenience or preference the revolving centre or point to be
maintained is connected with the shaft of the piston or to the body of the cylinder.

page_text: The distribution of the liquid on the two faces or surfaces of the turning or
revolving piston is made from the centre by aid of pipes communicating with the
regulator the distance and situation of which is optional. This regulator also bears
a cylinder enclosing a piston between two liquid masses or blocks whose total
volume is constant, but whose partial volumes cause a variation of the respective
volumes of the liquid blocks of the revolving or turning piston, so that the
displacement of the piston of the regulator determines a corresponding displace-
ment of the revolving piston. The regulator can also have a movable cylinder
or a fixed piston or a movable piston in a fixed cylinder, and the displacement
of the piston or cylinder as the case may be will be produced under the action of
an external force, by levers, screws, fly wheels and so forth, worked either by hand,
by steam, or by other means. To my knowledge this hydraulic process has never
before been used or known prior to my discovery thereof.
The hydraulic crank can be used for many purposes; as example I may mention
the motions and varying strokes of pumps and for various other objects, such as
governing the movements of various apparatus for distributing and transmitting
power and so forth. I have particularly studied one of its most complex and
important applications namely the distribution of steam of varying expansion, and
for reversing the motion of locomotives
The remarkable and special advantages of this hydraulic crank with respect to
its application as above will hereafter be dealt with more fully. In applying it
in the distribution of steam to locomotives, the following results are obtained.
1st Reduction to a minimum of frictional surfaces. 2nd Corresponding reduction in
the play of joints, articulations &c-3rd Maintenance of the phases of distribution
in accordance with the results of experience. 4th Reduction in the cost price of
the machine, and the expenses of repair. 5th Reduction in the weight of the
machine, or what is sometimes considered of more importance viz: the capability
of economizing weight by adding strength in the shape of thicker plates to certain
parts of the machine especially the boiler, so that it can bear a greater steam
pressure.
6th The facility of establishing an apparatus of unique construction
applicable to a number or series of machines.
Description of the hydraulic crank as applied to the distribution of steam of
variable expansion and for reversing the motion of locomotives-The accom-
panying drawings represent by Fig 1 the general construction of the apparatus.
Figs 2. 3. 4 and 5 the arrangement of the Regulator placed near the hand of the
driver. Figs 6. 7. 8. 9 and 10 show an arrangement of the revolving cylinder
borne by the driving crank A Figs 6 and 10 with axle of the connecting rod B.
The centre axle at C. bears (on each side of the machine) a hydraulic cylinder D,
firmly guided and containing a piston with double shaft E. The piston is fixed
to the driving crank and the cylinder is capable of displacement in its guide.
The movable cylinder bears the axle F, to which the head of the shaft G Fig 1
is connected which directly works the slide valve. By the displacement of the
cylinder D Fig 6, the axle F can occupy one of the extreme positions G. G₁. or
some intermediate point such as G₁₁. The distances G. C. G, C. G₁ C &c represent
various radii of eccentricity whose length varies at will from G. C and G, C for the
greatest eccentricity to G₁ C for the smallest. By this means various courses of
the slide valve are produced 2 G. C. 2 G₁ C &c and consequently varying lengths
of time for the introduction of steam to the driving cylinder, and corresponding
variations of expansion, eduction, and compression.
Moreover between the points G. C. G₁ C. the radius of eccentricity forms with
the axis H, a variable angle G C. H. on one side of the axis H, and between the
points G₁ C. G, C another similar angle G₁. C. H occurs on the other side of the
axis H, this result producing the reverse movement of the slide valve, and
consequently reversing the engine.
The displacement of the cylinder D, on its piston is effected by a distribution of
liquid on the two surfaces of this piston. For this purpose the liquid is conducted
through a rotating joint placed on the extension of the axis G with which this

page_text: joint displaces itself. Figs 7. 9. and 10 show the construction of this rotating
joint. I. I, are two surfaces in contact and perfectly polished, on which a central
orifice J. J, and an annular orifice K. K, debouch. The orifice J, turns with the
axle F, borne by the revolving cylinder and communicates by the conduit L, with
one end of this cylinder; the orifice J, belongs to a kind of plug M, which does not
turn and communicates with a pipe N. In the same manner the annular orifice K
turns with the cylinder D, and communicates by the conduit L, with the other end
of this cylinder and the orifice K, belonging to the plug M communicates with
a second pipe N₁. These two pipes N. N, do not turn, but they participate in the
oscillatory motion of the eccentric shaft to which they may be attached, as well as
the plug M if the pipes do not stop its rotation.
:
The contact of the two polished surfaces I. I, is assured by a ring O, Fig 10,
which bears the elastic pressure of a spring P. The part that encloses the rotating
joint may form by its spaces a sort of grease or oil box suitably closed, and fed by
a grease orifice S, for lubricating the polished surfaces I. I, and the surface T, on
which the ring O, presses.
a
In order to facilitate lubrication of the frictional surfaces I. I, and keep their
surfaces in contact, it suffices to give the surfaces; one of which turns whilst the other
is stationary slight and relative eccentricity which displaces the circles in contact, or
even if required I interpose between the two surfaces a plate which drawn on one
hand by the revolving surface, and held on the other by the fixed one, can turn at
a variable speed; this interposed plate may itself be slightly excentric relatively
with the two frictional parts it separates.
By this means a permanent polish is maintained; greasing the surfaces being
effected one after the other as they are drawn along, care being taken to soften the
edges of these surfaces, and when required to form notches or grooves on these
surfaces for the lubricating oil to run in.
The tubes or pipes N. N, are extended as shown N₁ Fig 1 to branch towards
the regulator, placed near the driver. The pipe N₁, is made flexible either by aid
of a movable joints or simply by twisting them like a hunters horn. Whilst in
motion the axle F to which the shaft of the slide valve is articulated is submitted
(under the influence of this slide valve) to the effects of varying degrees of
strain, which are borne by the liquid blocks contained in the revolving cylinder.
It is as well to check these effects being transmitted through the revolving joint
to the pipe N₁ and to the regulator. Amongst the applications of the system
Figs 7 & 8 represent the following. Q. Q₁ are two clack valves closing the
conduits L. L, these valves are united and rise and fall together so that in a back
flow of liquid by the conduit L raising the valve Q, which motion also raises the
valve Q, a corresponding discharge of liquid takes place by the conduit L, which
is reciprocal. R, Fig 7 represents plugs useful in filling or emptying the
apparatus.
Construction of the Regulator placed near the driver to govern the various
positions of the cylinder turning on its piston-The regulator Figs 2 to 5 com-
municates by means of pipes such as N₁ (two for each side of the machine) with
the two piston surfaces of the revolving cylinders borne by the driving cranks.
This regulator consists of two cylinders joined together A. A' of the same diameter,
and of the same course as the revolving cylinders (whether of an equal or a
superior volume to that of the revolving cylinders) These cylinders A¹. A¹, contain
pistons B. B, solidly united by the traverses C. C₁₁. The displacement of the
pistons in their cylinders can be operated by means of a screw E¹ turning in its
nut F, and governed by a fly G₁ placed near the driver. D. D¹ are the joints
of the pipe Nu for distributing the liquid on the two surfaces of the pistons.
1
To conveniently regulate the relative positions of the pistons of the regulator
and the revolving pistons borne by the driving cranks; above the cylinders of the
regulator may be placed simple plugs for filling, with or without joints from
which may be branched a small kind of hand pump either independent or not of
the apparatus, or as shown in the drawing Figs. 2. 3. 5. in which case there is a

page_text: filling space H which insures the apparatus being full, by always keeping the
liquid at a pressure superior to that of the atmosphere. The following description,
will explain the action of this filling space H. The whole apparatus (turning
cylinders, pipes, and space H') is full without air bubbles, the space H' is filled by
a tap J, a plunger K₁ pressed by a spring is governed as desired by a screw L' and
fly M', and the capacity H' may communicate with the cylinders A. A' by means of
the clack valves I. I-If after compressing the spring of the plunger K', the
tap J being closed the screw L' is turned which bears the plunger it will be
understood that the plunger under the action of the spring will press upon the
liquid and when required will make the valves I. I' descend when the pressure of
the liquid in the rest of the apparatus is lower than that in the capacity H.
The valves I. I close from bottom to top, to prevent the pressure of the cylinders
entering the capacity H¹; and their shafts may extend outside, and be worked by
hand to allow of regulating the volumes of liquid on the four surfaces of the
pistons, as well as the relative positions of these pistons. Moreover care should be
taken to mount on the revolving cylinders and on the regulators, indexes and
graduated scales so that the concorde or agreement of the pistons may be easily
and promptly read.
General considerations-The liquid used may be water but in the majority
of cases it is best to use a liquid which does not congeal in the cold winter months-
This liquid will have a fluid homogenity, it will be unctuous to assist in lubricating
the frictional surfaces, and as much as possible free from acids. Without exactly
specifying the liquid which experience would suggest as most suitable for each case;
as example I may mention glycerine, pure, or otherwise, pure oils, mixed oils, or oil
mixed with glycerine, alcohol and so forth.
The major part of the pieces of the apparatus may be of iron, cast-iron, forged
steel, cast steel, bronze or any other metal. The frictional surfaces I. I¹ of the
turning joints may be of tempered steel and should a plate be interposed between
these surfaces, this plate may be of steel, bronze, phosphoric bronze, or some alloy
that experience may recommend.
The turning joints may as the case requires be arranged in the form of taps,
swivels, stuffing boxes and so on, with hemp or metallic stuffing. The stuffing of
the pistons, their rods, the clack valves, the pipe joints &c may be of leather,
oakum, or any other substance or in metal.
If desired the Regulator which governs the revolving cylinders may have as
many cylinders as their are revolving cylinders, or it may have one only of
sufficient volume for all the revolving cylinders it governs, and all the several
cylinders of the regulator may be united or governed separately.
The hand fly wheel moved by the driver may be replaced by a hand lever, or by
steam mechanism or by any other suitable means for effecting with certainty and
rapidity the displacement of the pistons. The drawing shows the hydraulic crank
applied for governing a slide valve such as frequently used on locomotives; but the
hydraulic crank may also be used for actuating cylindrical slide valves, ordinary
valves or distributing organs, either directly, or with intermediaries (as example
the starting lever worked by the piston in the Walschaerts distributing system)
Then the positions G. G, with regard to the centre C (Fig 6) are determined on
a different scale in each application.
Finally I claim as my invention.
1 The novel system which I here repeat consisting of the government (close at
hand or at a distance) of the several positions of a revolving point or centre,
whilst in motion or at rest, and in keeping this point revolving between two
liquid blocks, whose respective volumes may vary whilst their total volume
remains constant and unchanged
2nd The application of this principle to locomotives without confining myself
strictly to the forms, and proportions indicated, such kind of machine, whether
locomotive or otherwise may perhaps require some special arrangement of
parts, without however deviating from the true principle herein described.

page_text: The means by which this system is put into practice its application to loco-
motives being mentioned as it is a particularly complex case interesting in the
practical results realized And as often as it is required to have cranks with
variable throw that is to say whose position on the driving shaft may be
differently determined in such case this novel invention will be of useful
application
In witness whereof I the said Jules Charles Müller have hereunto set my
hand and seal this seventh day of June in the Year of Our Lord One
thousand eight hundred and eighty three.
J. C. MULLER (L.S.)