IMPROVED MODE AND MEANS OF VARYING THE EXPANSION IN ENGINE CYLINDERS
Year: 1871

page_text: LETTERS PATENT to Lucien Guinotte, of Mariemont, in the Kingdom
of Belgium, Civil Engineer, for the Invention of "IMPROVED MODE
AND MEANS OF VARYING THE EXPANSION IN ENGINE CYLINDERS."
Scaled the 19th December 1871, and dated the 9th August 1871.
I, LUCIEN GUINOTTE, of Mariemont, in the Kingdom of Belgium,
Civil Engineer, do hereby declare the nature of the said Invention for
"IMPROVED MODE AND MEANS OF VARYING THE EXPANSION IN ENGINE CYLINDERS,"
to be as follows:-
My system or Invention allows of a great variation in the introduction
into an engine cylinder of the steam or other expansive fluid at any
desired degree from zero up to full expansion, and the application is
simple whether applied to machines with changing motion or to
machines with continuous rotary motion.

page_text: According to my Invention the distribution of the steam or other
motive fluid is effected by means of two simple slide valves placed one
over the other. One of these valves, which is the distributing valve,
is worked by any ordinary reversing gear and by two excentrics, while
the other valve, which is the expansion valve, obtains its motion from a
special slotted quadrant or link. This second link rocks on a shifting
centre, and is coupled at one end to the main valve and spindle. From
this arrangement the following results arise from reversing the lever
which changes the motion:- First, not only is the position and
working of the distributing valve altered, but the same effect is pro-
duced upon the expansive valve. Second, the conditions of motion of
the latter are quite as favorable either way. And, third, these results
are attained without the necessity for any other appliance, whether
the machine is one with changing motion or one with continuous
rotary motion.
By means of my Invention the steam is cut off at very nearly the
same period of the stroke for each reciprocation of the piston for all
degrees of expansion and at exactly the same period for any determined
amount of admission, such for example, as the mean admission, or the
admission at which the machinery usually works.
The Invention will be found particularly advantageous in machinery
for raising coal or other material from mines.
.
In machinery of this description it is not always easy to impart such
a winding or rolling radius to the ropes as will make the amount or
momentum of resistance permanent. When the mine is of great depth
the winding radius at the commencement is too small, and the lifting
of the cage therefore requires a great number of revolutions of the
winding drum; much time is thus occupied and the wear of the ropes
is considerable. In these cases it is usual to submit to irregularity in
the working so as to give a convenient winding radius, and the result
is a very imperfect use of the steam or other motive fluid. Now by
varying the degree of expansion in proportion to the resistance
regularity is established, and the steam is always used in a beneficial
manner in the cylinder. This result is attained by automatically
varying the position of the block in the slotted quadrant or link before
named.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Lucien Guinotte in the Great Seal Patent Office
on the 1st February 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LUCIEN
GUINOTTE, of Mariemont, in the Kingdom of Belgium, Civil Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Ninth day of August, in the year
of our Lord One thousand eight hundred and seventy-one, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Lucien Guinotte, Her special licence
that I, the said Lucien Guinotte, my executors, administrators, and
assigns, or such others as I, the said Lucien Guinotte, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVED MODE
AND MEANS OF VARYING THE EXPANSION IN ENGINE CYLINDERS," upon the
condition (amongst others) that I, the said Lucien Guinotte, my executors
or administrators, by an instrument in writing under my, or their, or
one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Lucien Guinotte, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement thereof, reference being had to the accompanying
Drawings, that is to say :-
My system or Invention allows of a great variation in the introduction
into an engine cylinder of the steam or other expansive fluid at any
desired degree from zero up to full expansion or full stroke, and the
application is simple, whether applied to machines with reversing or
changing motion, or to machines with continuous rotary motion in one
direction,

page_text: According to my Invention the distribution of the steam or other
motive fluid is effected by means of two simple slide valves placed one
over the other. One of these valves, which is the distributing valve, is
worked by any ordinary reversing gear and by two excentrics, while the
other valve, which is the expansion valve, obtains its motion from a
special slotted quadrant or link; this second link rocks on a shifting
centre, and is coupled at one end to the main valve and spindle. From
this arrangement the following results arise from reversing the lever
which changes the motion :-First, not only is the position and working
of the distributing valve altered, but the same effect is produced upon
the expansion valve. Second, the conditions of motion of the latter are
quite as favorable either way. And, third, these results are attained
without the necessity for any other appliance, whether the machine is
one with changing motion or one with continuous rotary motion.
By means of my Invention the steam is cut off at very nearly the
same period of the stroke for each reciprocation of the piston for all
degrees of expansion, and at exactly the same period for any determined
amount of admission, such, for example, as the mean admission, or the
admission at which the machine usually works.
The Invention will be found particularly advantageous in machinery
for raising coal or other material from mines.
In machinery of this description it is not always easy to impart such
a winding or rolling radius to the ropes as will make the amount or
momentum of resistance permanent. When the mine is of great depth,
the winding radius at the commencement is too small, and the lifting of
the cage therefore requires a great number of revolutions of the winding
drum; much time is thus occupied, and the wear of the ropes is con-
siderable. In these cases it is usual to submit to irregularity in the
working, so as to give a convenient winding radius, and the result is a
very imperfect use of the steam or other motive fluid. Now by varying
the degree of expansion in proportion to the resistance regularity is
established, and the steam is always used in a beneficial manner in the
cylinder. This result is attained by automatically varying the position.
of the block in the slotted quadrant or link before named.
My Invention will be fully understood by the annexed Sheet of
Drawings and Diagrams, and by the following description thereof:-
Figures 3 and 4 represent the general construction of my gear for an
engine which is always run in one direction. In these Figures the

page_text: crank is supposed to be on the dead point at M', and the direction of
rotation is indicated by the arrow. The main slide valve is driven by an
ordinary eccentric having its centre at D, while the expansion valve has
its motion communicated to it by a rod k, which is jointed to the spindle
of the valve at a, and is connected at 6 to a block sliding in the link G.
This link G has motion communicated to it, first, by being connected
at q to an eccentric having the eccentricity O Q, and keyed on the
crank shaft, so that its centre is at Q when the crank is at M¹; and,
second, by being coupled at s to another eccentric having the eccentricity
O S, and which is keyed on the crank shaft, so that its centre is at S
when the crank is in the position just mentioned. The position of the
sliding block in the link G is governed by the expansion lever L, this
lever being coupled to the rod k by means of the link d.
By comparing the Diagram Figure 1 with Figure 3 it will be seen
that if the sliding block is at x¹ the admission will be nil, while if it is
placed at the admission will continue for a period corresponding to a
movement of the crank from M' to M², and thus it follows that the point
of cut off may be varied from zero to full stroke, and any desired degree
of expansion attained according to the position of the block in the
link G.
In explaining further the details of this gear I shall follow the
geometrical method fully explained by Professor Zeuner, in his treatise
on valve gear, ["Traité des distributions par tiroirs dans les machines
à vapeur fixes et locomotives; par G. Zeuner, Professeur à l'Ecole
Polytechnic Fédérale de Zurich." An English edition of this work has
been published by Messrs. Spon, London.]
In Figure 1 let the eccentric by which the main valve is driven be
represented by its radius OD, the crank being supposed to be at M',
and draw Od symmetrical with O D with regard to the axis I G. Next
upon O d as a diameter describe the circle a¹ a² a³ . . . . having its centre
at e, and with O for a centre describe the circle 71 22 3 ... having a
radius equal to the outside lap of the main valve. This lap is represented
by or in Figure 2, in which Figure the centres of the valve and port
correspond. Draw the radius OQ, and when the crank is in this position
the edge of the main valve will cover the cylinder port by an amount
equal to rg, Figure 1, and the expansion valve may then uncover the
port in the main valve without there being any danger of steam being

page_text: readmitted into the cylinder after the cut off had taken place. From
the same centre O describe a circle c³ ³ ³ . . . . with a radius equal
(see Figure 2) to the distance between the face Y of the main valve and
that marked Z on the expansion valve, when the centre lines of the two
valves correspond. Next, from the middle point of O Q, (Figure 1)
draw U W perpendicular to OQ, and through the point Q draw Q p¹
and prolong this line by an amount e N equal to e J. Through the
point N draw Nf' parallel to the line Qp', and draw the line F¹ F'
symmetrical with regard to the axis I G, to the line Nf, or f¹ƒ".
The line F F being thus determined, it can be easily shewn that if,
instead of being driven by an eccentric having a radius and position
fixed and invariable, the expansion valve derived its motion from an
eccentric, of which the radius and position could be varied, so as to shift
the centre at will along a straight line from F¹ to F, (in such a manner
that the crank being at O M', the lines joining to the centre O, the
different points between F1 and F' should express by their lengths and
positions the radii of the variable eccentric,) then the period of admission.
of the steam to the cylinder could also be varied at will through all the
degrees between zero and the maximum length of admission permitted
by the main valve.
To find the position of the centre of the eccentric for any desired
period of admission, for instance, the period represented by the angular
movement of the crank denoted by M¹, M³, in Figure 1, proceed as
follows: Upon the radius O, M³, and from the point V at the centre
of Oc² erect a perpendicular V 83, which will cut the line U W at the
point 8².
Join O 82 by a straight line, and prolong the latter to meet
the line Qp at a point p². Join e p² by a straight line, and prolong
this line to meet the line Nf¹ and ƒ². From flet fall a perpendicular
upon I G, and prolong it so as to meet the line F¹ F at a point Fº.
This latter point will then denote the position sought for, that is to say,
the centre of the eccentric should, in order that the steam may be shut
off when the crank occupies the position M³ occupy the position F²
when the crank is at M'.
The same process as that just explained has been followed with regard
to the positions of the crank O M¹ and O M' in order to determine
the limits of movement F1 and F7 which the eccentric ought to possess
to be able to vary the degree of admission to the extent already referred

page_text: to. In the same way also operating upon the radius O M³ there has
been laid down in Figure 1 the position which the excentric driving
the expansion valve ought to occupy to give the period of admission
corresponding to the angular movement of the crank.M¹ M³. The same
process may evidently be followed for any degree of admission, it being
merely necessary to take as a basis of operations the radial line marking
the position of the crank at the moment when it is desired that the
suppression of the steam shall take place. I may remark that the
reopening of the port in the main valve will take place for all degrees
of expansion when the crank arrives at O Q, that is to say, when the
cylinder admission port is closed, and when the edge ¹ (Figure 2) has
already passed beyond the edge o¹ by a distance equal to rg (Figure 1).
This system of expansion gear thus consists in a realisation of the
variable expansion which would be obtained if the centre of the eccentric
driving the expansion valve could be moved at will along this line F¹ F",
in the manner I have supposed above, this line being laid down by means
of a diagram for each particular case in which it is intended to employ
the. system.
This diagram gives for each degree of admission the
minimum movement of one valve on the other.
To construct a variable expansion gear on the system above explained,
and which consists in varying, according to a certain law, the angle
and the radius of the eccentric by which the expansion valve is driven,
or producing an equivalent variation in the gear which takes the place
of such a variable eccentric, it is desirable to explain a second principle,
which not only forms the key to the system designed by me, but also
explains all the combinations to which it gives rise, and the numerous
arrangements which it enables to be obtained for each particular case
which may present itself. For this purpose I shall refer to Figures 3
and 4, in which the crank is at M', and O Q and OS are the positions
of the two eccentrics governing the movements of the points q and s of
the link. Now if the eccentric rods Q q or S 8 are sufficiently long, and
if the curvature of the link is not too great, (a state of affairs which
can always be easily obtained by giving sufficient length to the rod k
which determines the radius of the curvature of the link,) there may
without appreciable error be substituted for the geometrical movement
of the arc xx, that of the straight line q 8, passing through the centres
of the joints coupling the eccentric rods to the links. It may then

page_text: be easily demonstrated that any point ₺ in the line 98, dividing this
line into two parts st and q t will have the same motion as if it was
driven directly by an eccentric having the radius and position O T,
point T dividing the line Q S in the proportion-
QT: TS =
qt: ts.
the
The movements of other points x1, 1, x, &c. of the link may be
determined in the same way by the proportions-
LS
F¹ S S Q =
SQ = 1 8 :
x₁ 8 :
1
$ 9.
& q.
S Q
Q F
= 8 9
x 7,
&c.
the results being that the points x'₁, l', s, t, q, x7, &c. on the line q s
have respectively movements projected upon the line O M' from the
points F L S TQ F, &c. If then the sliding block be so placed in
the link as to correspond to the different points above named the
expansion valve will have imparted to it movements similar to those
which would be communicated to it by eccentrics having their centres
at corresponding points on the line F¹ F. In other words by shifting
the block along the link the expansion valve will be made to receive
movements varying in the same manner as if the centre of the eccentric
by which it was driven was shifted along the line F¹ F', the position
of this latter line being fixed with regard to the crank. The degree
of expansion will then be variable between the broadest limits.
Figures 5, 6, and 6" represent an arrangement in which a single
eccentric only is employed to impart the desired movement to the link.
The line F F7, which I term the "line of centres of the expansion
eccentric" cuts the line of the dead points M¹ O at X. O D represents
in all cases the radius and position of the eccentric for the main valve.
An eccentric Ox actuates the point x of the expansion link and also
the extremity of a lever xot, oscillating on the centre o.
The arms
of this lever being in the proportion ox: ot, the point t receives a
motion such as would be communicated to it by an eccentric O T, of
which the radius OT is in the proportion OT: O X = o t : o x, The
movement of the point t is communicated by a rod t t¹ to the extremity
of another levert dq jointed at d to the spindle of the main valve, the
point d thus participating in the movement of the main eccentric O D.
Join T D (Figure 6) and continue this line until it meets the line F¹ F'
at a point Q. The points t and d of the lever t'd q being actuated
by the movements of the eccentrics T and D, a third point q so situated

page_text: :
that qd d t = QD D T will have the same motion as would be
communicated to it by the eccentric O Q, and if there is conveyed by
means of the rod 6 this motion of the point q to the point q¹ of the link,
it will be seen that the same effect is obtained as if the point q' of the
link was coupled direct to an eccentric O Q.
Figures 9 and 10 represent an arrangement in which no expansion
eccentric is required. The point X marking the intersection of the
lines FF, and O M' (see Figure 6) is still adopted as the "centre of
command," but the eccentric having its centre at this point is replaced
by a lever mox, of which the end m receives its motion from the
piston rod. M¹ O being the radius of the crank it is sufficient evidently
to adopt for the lever the proportion M'O: 0X: = mo: 0x. The
lines OD and F F7 intersect at R. If a second lever do'r, oscillating
on a fixed point o' receives at the extremity & the movement of the
spindle of the main valve, that is to say, if it is driven by the eccentric
D, the other extremity will receive the same motion as if it was driven
by an eccentric R, provided the proportions of the lever are such that
OD OR o' d o¹ r. Then x and r will be the two points of the
expansion gear, which will represent the movements of the line F¹, Fr.
The examples of my gear which I have so far considered are applicable
to engines which are continually run in onc direction. I now proceed
to describe the system as applied to engines fitted with reversing
gear, and for this purpose I shall refer in the first to the diagram,
Figure 11.
:
In this Figure the crank being at M¹ the main eccentric for motion
in the direction Z is situated at D, and that for motion in the direction
Z at D. Regarding the movements in the two directions independently,
that is to say, treating cach of the eccentrics D and D' separately in
the manner followed when considering the case of an engine moving
in one direction only (Figure 1), I find a line of centres for the expansion
cccentric for cach direction of motion, the line F¹ F² F³ . . . F, being
for motion in the direction Z and F1, F2, F's. . . F', for that in the
direction Z. The lines F, F',, cut the line of the dead points M¹³ O, this
being a prolongation of the radius of the crank at the point X, and one
of the points of the link can thus be actuated by a movement identical
with that which would be imparted to it by an eccentric O X, and the
movement of this point will apply equally to the motion of the engine
in either direction Z or Z'. This movement can be obtained either by
7

page_text: the engine is running in the direction Z and the line X Q¹ when the
motion is in the direction Z. In other words, it will be seen that by
moving over the reversing lever the motion imparted to the point q
of the expansion link will be changed, and the link will be made to
represent the line F F or the line F₁, F7, according to the position
which the reversing lever occupies.
I will give one more example, see Figures 14, 15, and 16, and the
diagram Figure 14°. In this arrangement there is no special eccentric
for the expansion valve. The joint m' of the lever m, m¹ o derives its
motion from the piston rod, and the two arms o m¹, o m₁, being in
the proportions given by the equation o m¹: o m₁ = O M' : O M₁, it will
be seen that the point m' and in consequence the two points m² and m³
receive the motion which would be imparted to them by a direct attach-
ment to an eccentric O M'. The point m² is situated on a lever m², o¹, X,
of which the two arms are in the proportion m² o¹ o' x =M 0 : 0 X,
from which it follows that the point of attachment x of the expansion
link has a motion such as would be given to it by an eccentric O X.
:
A third lever m³ d q' having its fulcrum d on the main valve
= M'D: D
spindle, and having its arms in the proportion m³ d : d q¹
QM' D D' Q' carries the motion to the point q, whence it is com-
municated by the rod q¹ q to the second point of attachment q of the
expansion link; this point having thus a motion similar to that which
would be imparted to it by an eccentric OQ during the motion of the
engine in the direction Z, and by an eccentric Q Q when the engine is
running in the direction Z'. Thus the expansion link in this case also
represents the lines F F or F', F'7, according to the position of the
reversing lever and the direction in which the engine is running.
I may remark here that if the reversing lever should not happen to
occupy the one or the other of its extreme positions no inconvenience
will result, and the expansion will remain variable within the limits
allowed by the proportions of the main valve. It will be seen from
what has been already stated that when an engine fitted with the gear
I have described is reversed not only is the movement of the main
valve modified in the required manner, but the conditions under which
the expansion valve acts are at the same time altered to suit the change
in the direction of rotation of the crank shaft without causing any
additional trouble to the engine man. In fact the lever governing the
action of the expansion valve need only be touched when it is required
.

page_text: to vary the point of cut off, and if the expansion gear is once set to any
desired cut off the engine can be reversed to and fro without interfering
with the action of the expansion valve.
Figures 12, 13, 17, 18, and 19 represent two engines fitted with
reversing gear to which my expansion gear has been applied in a manner
identical as to principle and general arrangement with that shewn in
Figures 14 and 15. The point of cut off can if desired be made to vary
continuously and automatically, an arrangement which it is advan-
tageous to adopt in cases when from the resistance, being variable it is
desirable to vary the admission of steam in such a manner as to maintain
a constant equilibrium between the power developed and the work to be
done. Such a case, for instance, is that of winding engines for mines,
&c. Take, for example, a winding engine in which the law governing
the variation of the work to be done at each revolution is known, and in
which consequently the degree of expansion to be employed at each
revolution can be ascertained, in this case the block instead of being
shifted in the expansion link by hand can have its position adjusted by
the engine itself, as shewn by Figures 17, 18, and 19.
Referring to these Figures it will be seen that the rod i carrying
the block is supported by being jointed to a sustaining link a b, this
latter link being attached at b to a lever b c keyed on the shaft c, on
which there is also fixed the lever c d. By means of the connecting
link de the lever c d is coupled to another lever ef keyed upon a
shaft, which also carries the curved lever f g h. The position of the
sliding block in the expansion link is thus dependent upon that of the
curved lever just mentioned. Another shaft f¹ carries another curved
lever f¹gh. The two levers f g h and f¹ g¹¹ are connected to
cach other by the levers fm and f¹ m', the rods m n and m² n', and
the double lever n p n', the connexion being thus such that the curved
levers f g h and f¹ g¹ h¹ move symmetrically. A counterpoise a
placed at the end of a lever fl tends to maintain the whole system
of levers of which I have just been speaking in the position in which
they arc shewn by the full lines in Figure 17, this position corresponding
to the full admission of the steam. The crank shaft by means of the
bevel gear A B gives motion to the screw C D. This screw carries 3
two nuts, of which the one E is provided with a small lever rs (see
the plan Figure 19), which is pivoted so that it can turn from left to
right but not from right to left. This levers carries a small friction

page_text: roller t, which is situated in a line with the curved lever f g h. The
other nut E' is in like manner provided with a levers, this lever
carrying a friction roller t, which is in a line with the curved lever
fgh. The arrangement is such that when the engine is running
in the direction shewn by the arrow Z' in Figure 17, the two nuts E
and E', which cannot turn with the screw C D have imparted to them
a rectilineal movement from left to right. Under these circumstances
the friction roller presses upon the lever fg h, and causes it to be
moved downwards towards the position shewn by the dotted lines, the
sliding block k being of course at the same time moved down in the
expansion link and an earlier cut off of the steam produced. Eventually
the system of levers will occupy the positions shewn by the dotted lines,
this taking place three or four revolutions before the cage which is being
lifted by the engine arrives at the bank level. A little later, just before
the end of the lift, the friction roller clears the end of the lever ƒ g h,
and disengages it, when the counterweight causes the whole system of
levers to assume the positions shewn by the full lines, thus giving the
steam admission for full stroke. While the operations above described
have been going on, that is, while the nuts E and E' were moving from
left to right, the friction pulley on the lever connected to the latter
nut will have encountered the lever f¹ g¹¹. This lever, however, will
approach the roller from above and from the right-hand side and lever
rs, by which the roller t¹ is carried, being pivoted so that it can turn
from right to left, it will yield to the pressure of the lever f¹ g¹ h³, and
will on passing that lever be caused to resume its normal position by the
springs shown in the plan. In this way the roller t will be changed
from a position below to one above the lever f¹ g¹ h¹. During the
following "lift" the engine will run in the direction shewn by the
arrow Z, and the screw C, D, will thus be turned in the opposite direction
to that in which it previously ran, and the two nuts E E¹ will thus
be caused to move from right to left. Under these circumstances
the friction roller will operate upon the lever f¹ g¹ h' in the
same manner as the lever f g h was operated upon by the roller t
during the preceding lift. During the successive
lifts" therefore,
the degree of expansion will be varied according to the same law
whatever may be the direction in which the engine is running, so
long as the two levers f g h, f¹ g'', are made to the same curve,
as will ordinarily be the case; but if circumstances should render it
advisable the degrees of expansion can be varied according to different
"

page_text: -
laws in the alternate lifts, simply by modifying the shape of the levers
just mentioned. Such a case might occur, for instance, when an engine
was used to work two drums of different diameters, making lifts
alternately from two shafts of different depths. It is evident that the
curvature to be given to the levers f g h and f¹ g¹¹ has to be
determined by an investigation of the degree of expansion admissible
during each revolution, and this investigation will be a special one for
each particular case.
In the engine shewn in Figures 17, 18, and 19 the screw C, D, is
also employed for actuating the bells which indicate the position of the
cage which is being raised; these bells being arranged as shewn, and
the nuts E, E¹, being provided with striking pieces which come into
contact with the bells at the proper points towards the end of each lift.
Moreover, as the movements to and fro of the nuts E E¹ correspond
with the rise and fall of the cages in the mine, the engine man in charge
at all times has the means of knowing the exact positions of the cages
in the shaft.
In case of accident the engine man by placing his foot upon the
pedal P can suddenly admit full steam to the engine. The lever efin
place of being keyed rigidly upon the shaft fis connected to it by means
of the clutch F (see Figures 17 and 18) which is actuated by the
pedal P. On this pedal being pressed by the engine man the clutch
just mentioned is disengaged, and the sliding block k rises to the top
of the expansion link under the influence of the counterweight 7. On
the other hand, when the pedal is released, the clutch is thrown into
gear again by means of the counterweight G the moment the system of
levers assumes the positions corresponding to a full admission of the
steam.
From the particulars which I have given above it will be seen that
my system of expansion gear is capable of a wide range of applications.
In the case of winding engines it affords a perfect means of auto-
matically adjusting the degree of expansion to the resistance at all parts
of the lift, while at the same time the engine man can at any time at
once apply full steam if it should be necessary to do so.
In the case of engines having the winding drums proportioned so as a
to give a sensibly constant resistance, the arrangement for varying the
expansion as last described would not be required, but a constant degree
of expansion may be used throughout each lift, simple means being

page_text: employed by which the engine itself is caused to place the gear into the
proper position for admitting full steam shortly before the cage which
is being raised "comes to bank."
And having now described the nature of my said Invention, and in
what manner the same is to be performed, I declare that I claim, the
mode and means herein-before described of varying the expansion
in engine cylinders.
In witness whereof, I, the said Lucien Guinotte, have hereunto
set my hand and seal, this Twenty-second day of January One
thousand eight hundred and seventy-two.
LUCIEN GUINOTTE. (L.S.)