IMPROVEMENTS IN MACHINERY FOR RAISING AND LOWERING WEIGHTS AND PERSONS IN MINES, AND IN THE ARRANGEMENT AND CONSTRUCTION OF STEAM ENGINES EMPLOYED TO PUT IN MOTION SUCH MACHINERY, PART OF WHICH IMPROVEMENTS ARE APPLICABLE TO STEAM ENGINES GENERALLY
Year: 1849

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
COWPER, of Southampton Buildings, in the County of Middlesex, Patent Agent,
send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-third day of
August, One thousand eight hundred and forty-nine, in the thirteenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Charles Cowper, my exors, adñiors, and assigns, Her especial licence,
full power, sole privilege and authority, that I, the said Charles Cowper, my
exors, adiiors, and assigns, or such others' as I, the said Charles Cowper, my
exors, adiñors, or assigns, should at any time agree with, and no others, from
time to time and at all times during the term of years therein expressed, should
and lawfully might make, use, exercise, and vend, within England, Wales, and
the Town of Berwick-upon-Tweed, and in the Islands of Jersey, Guernsey,
Alderney, Sark, and Man, and also in all Her said Majesty's Colonies and
Plantations abroad, the Invention of "IMPROVEMENTS IN MACHINERY FOR RAISING
AND LOWERING WEIGHTS AND PERSONS IN MINES, AND IN THE ARRANGEMENT AND
CONSTRUCTION OF STEAM ENGINES EMPLOYED TO PUT IN MOTION SUCH MACHINERY,
PART OF WHICH IMPROVEMENTS ARE APPLICABLE TO STEAM ENGINES GENERALLY,"
communicated to me from abroad; in which said Letters Patent there is
contained a proviso that I, the said Charles Cowper, shall cause a particular"
description of the nature of the said Invention, and in what manner the same
is to be performed, by an instrument in writing under my hand and seal, to

page_text: be enrolled in Her said Majesty's High Court of Chancery within six calendar
months next and immediately after the date of the-said in part recited Letters
Patent, as in and by the same, reference being thereunto had, will more fully
and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Charles Cowper, do hereby declare that the nature of the Invention, and the
manner in which the same is to be performed, are particularly described and
ascertained in and by the following statement thereof, reference being had to
the Drawings hereunto annexed, and to the figures and letters marked thereon
(that is to say) -
:-
The Invention consists,-
Firstly, in certain improvements in machinery for raising and lowering
weights and persons in inines, by means of reciprocating rods or spears.
Secondly, in certain improvements in the arrangement of steam engines
employed to put in motion the aforesaid machinery. And,
Thirdly, in certain improvements in the construction of the valve gear of
steam engines employed to put in motion the aforesaid machinery, which last
improvements are applicable to steam engines generally.
The three Sheets of Drawings hereunto annexed shew the machinery in
different views, and with sufficient details to explain the construction and action
of the different parts. Thus Sheet 1, Figure 1, represents a horizontal section
of the shaft of a mine, showing the construction of the machinery for ascent
and descent, and the arrangement of the whole. Figures 2 to 9, inclusive, in
the same Sheet, shew the details of the principal parts. Sheet 2, Figure 10,
represents a vertical section of the shaft fitted with the apparatus. This Figure,
and Figure 11 on the same Sheet, also represent one of my arrangements for
giving a long up-and-down stroke to the spears. Sheet 1, Figure 12, shews the
detail of the excentric motion for reversing the engine. Sheet 3, Figure 13,
is a vertical section, and Figure 14 a plan of another arrangement for ob-
taining the up-and-down motion. I call this arrangement a hydraulic balance.
Lastly, the Figure 15, Sheet 2, and Figures 16 and 17, Sheet 3, represent
the different positions of a system of machinery for raising and-lowering-weights...
and persons in mines, analogous in principle to one which has been used in
Cornwall for raising the workmen, but differing from it essentially as regards
its construction and application.
The machinery shewn in Figures 1 and 10 consists of four spears united
in pairs by two flat link chains passing over two polygonal plates or wheels,
fixed on the same axis, and receiving a rotary motion from a steam
engine or other motive power. I intend to employ, according to circum-

page_text: stances, whatever motive power may be most convenient. The spears T, T,
Figure 1, Sheet 1, move together in one direction, whilst the spears T, T,
move together in the opposite direction. In Figure 10, Sheet 2, is shewn
a section of one of the polygonal wheels X, and the connection of the
spears T and T₁ with the chain. a, a, are simple catches fixed on the cross
beams A, moveable with the spears to which they are attached. a', a¹, are
similar catches fixed in the shaft ou the cross beams M. I call "a catch"
a piece of metal of the form shewn in Figure 2, moveable on an axis i, and
capable of taking the position shewn by the dotted lines when it is raised, but
which falls back into the horizontal position when left to itself. I employ two
sorts of catches, one being the simple one above described, and the other pro-
.vided with a lever and balance weight, which last I call a lever catch. b, b, are
lever catches fixed on the cross beams A', moveable with the spears T. These
catches, when left to themselves, assume the position shewn in Figure 9, from
the action of the balance weight or counterpoise P. 61, b', are lever catches like
those just mentioned fixed in the shaft on the cross beams N. When left to
themselves they take the position shewn in Figure 5, by means of the counter-
poise P. G, G, are wooden guides fixed to the cross beams M, N, and
extending from top to bottom of the shaft to receive and guide the extremities
of the cross beams A, A, and serving also as guides to the spears T, T'. G¹, G¹,
are wooden guides like the former, but serving as guides for the carriages, the
position of one of which is shewn by the dotted lines o, in Figure 1. L, L,
are levers turning on an axis for working the lever catches b. S, S, are tappets
fixed in the shaft and projecting in such positions that at the top of the stroke
of the apparatus they meet the levers L, and thus cause the lever catches b,
to assume the position shewn in the plan in Figure 1, and in elevation in
Figures 7 and 8. L', L', are levers attached to a spindle D, by means of which
the lever catches are worked. Figure 5 represents the position of these
catches at the top of the stroke, and Figure 6 represents them at the bottom
of the stroke. Q, Q, are tappets, which in descending, press upon the levers
L', and depress the catches b', as already described. The tappets Q, with their
levers L', are disposed alternately on the right and left side of the apparatus,
and the tappets S, S, and levers L, are also placed alternately on each side of the
weight P, so that in the crossing of the movements of two adjacent stages
there may be no obstacle to the motion of the apparatus.
From the above description it will now be easy to understand the action of the
apparatus. The length of stroke may be varied to a great extent according to the
system of motive power employed. The arrangement of motive power herein-after
described is easily arranged to give a length of stroke of fifty feet, and I will

page_text: suppose that length of stroke to be employed, and that the stages are placed
at intervals of forty-six feet apart, both for those fixed in the shaft, and for
those attached to the spears, so that in the reciprocating movements of the
spears, the moving stages may rise two feet above and descend two feet below
the fixed stages.
It will now be seen that if a carriage or box is placed on
the fixed catches a², Figures 1 and 10, and the spears T are caused to descend
the catches a will meet the carriage, and assume the position shewn by the
dotted lines in Figure 2; as soon as they have passed below the carriage they
will fall into the horizontal position, and descend until at the end of the stroke
they are two feet below the carriage. The motion being now reversed, the
spears T will rise, and the catches a meeting the carriage will raise it forty-
eight feet, or two feet above the catches a' on the next fixed stage, which
catches will rise as the carriage passes them, and then fall into the horizontal
position again. The motion being now reversed, the carriage will descend
two feet and rest on the catches a', while the spears T descend in search of
another carriage. On the spears T again rising they will lift a second carriage
from below, and at the same time lift the first one by means of the catches
on the next moving stage, and by this means at each double stroke of the
spears Tone carriage will be delivered at the mouth of the shaft, while each
The descent of the
of the other carriages will be raised forty-six feet.
carriages is effected by means of the spears T₁, T, which work in a separate
compartment of the shaft. The lever catches occupy the position shewn in
Figure 9 during a great portion of the upstroke, but when they arrive within
about four feet of the top of the stroke, the levers L meet the tappets S,
Figures 1 and 8; the catches b then take the horizontal position, as shewn in
Figure 8, and if a carriage is resting on the corresponding stage, it will be
raised two feet, and the catches being left to themselves will take the
position shewn in Figure 5, and will offer no obstacle to the descent of the
carriage. The spears being now caused to descend, will carry the carriage
with them until they arrive at four fect from the bottom of the stroke, the
tappets Q, shewn in Figures 1, 8, and 9, making the levers L', Figure 1,
cause the catches b' to take the position shewn in Figure 6.
The spears con-
tinuing to descend leave the carriage on-the-catches_b₁, and descend two feet
lower. The catches 6 are thus relieved from the load, and the levers L being
no longer in contact with the tappets S, which only act at the upper part
of the stroke, the catches assume the position shewn in Figure 9 by the
action of the counterpoise P. If the spears T now resume their ascending
motion the catches & pass the carriage without touching it, and ascend to fetch
another carriage from the upper stage, and thus the descent from stage

page_text: to stage is effected. Thus all the motions proceed without interference,
and each stage may be furnished with a carriage, so that at cach complete
or double stroke a full carriage is brought to the surface whilst an
empty one descends, and by increasing the number of strokes and the
size of the carriages, the quantity of material raised in a given time may
be much increased.
Figure 10, Sheet 2, shews the arrangement for introducing and with-
drawing the carriages or boxes from the apparatus. A is a platform turning
on the axis I, and capable of closing either the ascending side B or the
descending side C of the machinery. P is a balance weight, which always
brings the platform A into the position shewn in the, Drawing, when it is
free to move. L is a lever on the axis I, connected by a rod L, K, with the
The axis I also carries a segment
lever D, O, K, turuing on the axis O.
H shewn in Figure 10 b, where R is a latch which retains the segment H, as
shewn in the Drawing. When the end T of the latch R is raised, the seg-
ment His liberated, and the weight P, Figure 10, brings the platform A into
the position as shewn. S, Figure 10 b, is another lever connected to the lever
R by the link U. By raising the lever S the same effect is produced as by
raising T. A link W connects the lever which carries the balance weight P
to a lever X, Y, Z, turning on the axis Z. Supposing the carriage V to be
ascending it will meet the lever D, and thus throw the platform A over to the
descending side C of the apparatus, where it will be retained by the latch R.
The carriage V continuing to ascend will rise above the platform A, and will
then detach the latch R by means of a pin or tappet acting on the end T. The
platform A will immediately fall into the position shewn in the Drawing. The
carriage will now descend and be left on the platform A, whence it is imme-
diately run off by a workman stationed at the mouth of the shaft. The spears
will now descend to seek another carriage. At the same time the spears on the
side C are ascending, and a pin coming in contact with the lever X, Y, Z,
throws the platform on to the side C. An empty carriage is immediately run
on to it by a workman, and as the spears rise they lift up the carriage above
the platform, and raise the lever S shewn in Figure 10 b. The platform A
immediately falls over into the position shewn in the Drawing, and the spears
descend with the carriage. Instead of the double platform. A two separate
platforms may be employed working independently of each other on the two
sides B and C. At the lower part of the shaft is a platform M, on which
loaded carriages are run from the level N, whence they are lifted by the spears.
A similar platform on the descending side receives the empty carriages which are
pulled off by a workman. F shows another platform at a lower level, to be

page_text: used when loads are to be raised from two different levels. The platforms M
and F turn axes a, a, with a balance weight E, and are connected by a rod so
that when one is open the other is shut. This is to prevent two carriages from
arriving at the same platform at the same time. The platforms on the
descending side do not require to be connected. The various levers above
mentioned are arranged on the outside of the machinery so as not to interfere
with the passages of the carriages or boxes. The workmen may ascend and
descend in the carriages used for raising the minerals, or by means of small
platforms fixed on the back of the spears at intervals of fifty feet, and
provided with a rail for the men
to grasp.
The men step on one of
the platforms at the bottom of its stroke, and are raised fifty feet; they
then step on a fixed platform and wait until the downstroke is completed.
A second platform has now descended to the level of the fixed plat-
form; by stepping on this second platform they are raised another fifty feet,
and so on.
The descent is made in a similar manner. In some cases
two spears moving in opposite directions may be placed near each other, and
platforms fixed on each; the men then step from one to the other, and not
on any fixed platforms. In this way the ascent and descent are made in a
similar manner to that practised in an apparatus used in Cornwall, which
apparatus, however, is regulated by a crank motion, and is not applied to the
raising of minerals. In some cases two spears may be used, working
alternately, and acting on the same carriages, so no fixed stages are required.
The carriage is then raised the whole length of stroke by one spear, when
it is caught by the other and raised another stroke, so that it is raised at
a double speed. The descent can be effected in a similar manner. These
variations are mentioned to shew that the apparatus is susceptible of
being varied to suit the requirements of different cases. The raising of
water from the mines may be effected in a variety of ways, either by raising
it in carriages or boxes in the manner above described, or by attaching the
rods of pumps at once to the spears, or by communicating motion to pumps
from the pulleys, which should be placed at intervals in the shaft, and over
which are carried ropes or chains attached to the spears T and T', for the
purpose of balancing them.
I will now describe another variation of the lifting machinery, based on the
system which has been used in Cornwall, for raising and lowering the workmen,
and which system consists of two spears placed side by side and endowed with
alternative and opposite reciprocating motion. These spears carry steps or plat-
forms which come level with each other at the end of their stroke; the workmen
seize this moment to step from one platform to the other, and thus ascend or

page_text: descend according as they shift their position at the top or bottom of the stroke
of the platform on which they are standing.
Figure 15, Sheet 2. and Figures 16 and 17, Sheet 3, represent an
arrangement on a similar principle, but with certain important alterations,
by which it is made applicable to the raising of minerals. Each spear T, T',
carries a series of platforms turning on axes i, as shewn in section and
plan at Figure 15, Sheet 2. Each platform is provided with rails turned
up at one end, as shewn in the Drawings, forming a sort of cradle to
receive a carriage on wheels. The platform can incline either way on
the axis i, but is prevented from moving beyond a certain moderate incli-
nation by means of stops fixed on the spears T, T'. Figure 15 shews the
apparatus at half stroke and unloaded. Figure 16 shews the apparatus with
the spears T at the top of their stroke, and Figure 17 shews them at the
bottom of their stroke. Whilst the spears T ascend the distance from A³ to
A2, the spears T will descend the same distance, and the carriage which is on
A will now be opposite to B', having passed B2 during its ascent. As the
spear T attains the top of its stroke the platforms meet the pins or tappets
t, t', fixed in the shaft, and they are thus tilted into the positions shewn in
Figure 16. The carriage M immediately runs by its weight from the platform
As on to B', whilst the carriage D runs from B' on to A³; the motion of the
spears is now reversed, and continues until they are in the position shewn
by Figure 17. The rails on the platforms are so arranged that the centre
of gravity of the carriages and its contents is beyond the axis i, so that
the platform retains its position after quitting the tappets t, t. At the
other end of the stroke the platforms meet other tappets, as shewn in
Figure 17. On examining the Figures it will be seen that the carriages
marked M will ascend whilst those marked D will descend. It will be
that in the various modifications of machinery above described the
catches and tappets are attached to the machinery, and not to the carriages,
and therefore they are not liable to be injured by the rough usage which the
carriages may receive both in the mine and on the surface.
seen
I will now proceed to describe the mode of applying the motive power to
the above described machinery. I have already stated that the spears may
have a reciprocating motion of a very long stroke. The steam engine and
other machinery shewn in the upper part of Figure 10 is an arrangement well
adapted for producing this result. The spears are united by flat link chains
passing over the wheels X', X', which gear into them, and receive their motion
from a steam engine; according as the engine works in one direction or the
other, the spears T ascend or descend until they approach the end of the
.

page_text: .
:
desired length of stroke. A lever, suitably arranged to act on the slide valve
of the engine, then gradually checks the entrance of the steam until the
spears are brought to rest at the end of the stroke, when the steam is admitted
to the engine in the contrary direction, and the motion of the spears is reversed.
This reversing of the motion is effected by the machine itself and by any of
the means used for the reversing of locomotive or other engines, with the
exception that the arm of the engine driver is replaced by a lever acted on by
the machine at the top and bottom of its stroke.
Each of these
Another method is that shewn in the Drawings, Figure 10 and 11, in
which a pair of horizontal steam engines act upon one crank shaft Y as in
the ordinary locomotive engine. On the shaft Y is a pinion 6, Figure 11,
which gears into the large wheel 7 on the shaft X, carrying the polygonal
plates X and chains X, X. Y is the crank shaft with the excentrics fixed
upon it in the same direction as the cranks themselves. The excentrics give
motion to rods, one of which is indicated by the line Y, Z.
rods carries at its upper extremity rollers which slide in grooves in two plates
B fixed upon a shaft C, which is capable of being turned on its axis into
different positions as shewn upon a larger scale in Figure 12. The blue lines,
Figure 10, shew the position of these plates and the various parts when the
crank shaft is revolving in one direction, and the red lines shew the position of
the parts when it is revolving in the opposite direction. By examining the
connection which exists between the rods Y, Z, F, H, H, I, and the slide
valve of the engine, the action of the parts will be understood. The excentric
gives an up-and-down motion to the rod Y, Z, the roller at the extremity
runs up and down in the inclined grooves in the plates B, and the point F
describes a curve of a form resembling an ellipse, and consequently gives motion
to the slide valve by means of the rod F, H, and lever H, I. C, O, is a lever
attached to the plates B, and connected to a rod o, d, and by means of which
the inclination of the grooved plates B may be varied. It will be found that
bringing the groove gradually towards a vertical position has the effect of cutting
off the steam at a smaller portion of the stroke of the piston and thus checking
the speed of the engine, and the lap of the valve is so arranged that it remains
completely closed when the groove in the plate B is vertical. On gradually in--
clining the plate in the opposite direction it will admit a gradually increasing
quantity of steam to drive the engine in the contrary direction. It will thus
be seen that the effect of gradually moving the rod o, d, is to gradually stop
the engine, and start it in the contrary direction. The motion is communicated
to the rod o, d, in the following manner:-On the shaft X is a wheel 8 round
which passes the endless chain 9, which is kept extended by passing round

page_text: the wheel 10. On this chain are two projections or tappets R, which alter-
nately come in contact with the sector t, s, fixed on the spindle E, which is
capable of moving through one quarter of a revolution. On the spindle E is
also fixed another sector, carrying the weights W, U.
This spindle E also
The tappets are so
s, a little before the
carries a lever E, E', which is connected to the rod d, o.
arranged on the chain that one shall meet the sector t,
end of the upstroke of the spears T, whilst the other tappet shall meet the
other side of the sector a little before the end of the down stroke. If we now
suppose the different parts to be in the position shewn by the blue lines in
Figure 10, and that one set of the spears has nearly completed its downward
stroke, the corresponding tappet will come in contact with the lower horn or
spur of the sector t, s, and gradually raise it, reducing the supply of steam and
the speed of the engine until the weights W, U, overbalancing the sector, will
cause it to assume the position shewn by the red lines, and the engine will
immediately start in the opposite direction. To prevent the engine from starting
too rapidly, the weight W is not allowed to fall immediately into the position
shewn by the red lines, but is checked by means of a cataract K, consisting of
a plunger working in a cylinder filled with water, and provided with a small
opening for the escape of the water; when the weight W rests upon the
plunger of the cataract it gradually descends, and thus gradually admits the
steam to the cylinder. A similar cataract is placed to receive the weight U,
when the other tappet comes into contact with the upper spur or horn S of
the sector t, s. These cataracts may be raised by a system of levers acted
on by the lifting machinery itself, or by any of the well-known methods
employed for raising cataracts. The length of stroke given to the spears may
be accurately adjusted by varying the position of the tappets on the endless
chain. 11, in Figure 10 and 11, is a double snail wheel, to which is attached
a chain and balance weight working in a pit. This is for the purpose of
balancing the weight of the chains which carry the spears, and which would
otherwise alternately preponderate on either side of the polygonal wheels. By
the means above described we may give a stroke of almost any required length
to the spears, whereas if a crank were employed to communicate the motion
to them it would require to be of such length as to be very inconvenient.
Thus a stroke of fifty feet would require a crank twenty-five feet long, and if
a shorter crank were used in combination with levers to increase the length
of stroke to fifty feet, it would be found that the levers would be inconveniently
long if not absolutely impracticable from their great weight and friction.
I will now proceed to describe another means of giving motion to the
improved lifting machinery which is shewn in Sheet 3, Figures 13 and 14,

page_text: and which I call a hydraulic balance. A, A, are two steam cylinders
driving a shaft B, which carries a pinion O geared to the wheel P, on
the shaft G, which revolves considerably slower than the shaft B. The
shaft G carries a pinion Q, which drives two racks, K, K, working in
guides and attached to the plungers L, L, in the pumps M, M. These
pumps or cylinders are in connection with the long vertical cylinders R, R,
placed over the shaft of the mine and fitted with pistons S, S, to the rods of
which are respectively attached the spears on the ascending and descending
sides of the lifting machinery. The plungers L, L, being of larger diameter
than the cylinders R, R, it is evident that the stroke of the piston S will be
longer than that of the plungers L, L, and these diameters should be so pro-
portioned as to give the length of stroke which may be required. The stopping
and reversing of the motion is effected by similar means to those already
described, the grooved plates similar to those shewn at B, Figure 12, Sheet 2,
being moved by tappets attached to the racks K, K. The pistons S are made
hollow and contain a portion of air, which serves as a spring, and prevents any
injurious shock being caused by the changes of motion. Instead of the
racks K, K, the shaft G may carry at each end a crank driving the plungers
L, L, by means of connecting rods, and a single engine with a fly wheel on
the shaft B may be employed, the movement being continuous. It will then
be unnecessary to employ the reversing gear. I, however, prefer the previously
described arrangement, as the stopping and reversing can be very accurately
adjusted by means of the valve gear and tappets so as to avoid all injurious
shocks. Where a sufficient fall of water can be obtained, it may be introduced
at once to the cylinders R, R, giving motion to the pistons S. The supply of
water will then be checked towards the end of the stroke by tappets connected
to the spears, gradually shifting the valve, the water being turned on to one
cylinder whilst it is allowed to escape from the other. The piston S may also
be driven by steam instead of water and the steam valve will then be gradually
closed by means of tappets, as the spears approach the end of their stroke;
but I give the preference to the employment of an engine which makes several
strokes for each stroke of the spears. The pistons S may also be driven by
compressed air, or by withdrawing the air from the upper part of the cylinder
R, which would then be provided with an air-tight cover, whilst the bottom
was left open to the atmosphere.
That part of my improvements which is applicable to steam engines generally
consists in the combination of the excentric with the rod Y, Z, grooved
plates B, and rod F, H, shewn in Figures 10 and 12, by means of which
the amount of expansion may be varied without stopping the engine by

page_text: merely altering the inclination of the plates B. By simply altering the
position of a single lever attached to the plates B, one engine, or two or
more engines in proximity to one another, may be started, stopped, or
reversed, and the amount of expansion varied. In some cases it will be found
advantageous to connect the lever which is attached to the plate B to the
governor of the steam engine, so that when the speed of the engine increases
it may reduce the quantity of steam admitted, thus giving a greater amount of
expansion and checking the speed of the engine.
Having now described the nature of the Invention, and in what manner the
same is to be performed, I wish it to be understood that I do not claim
generally the application of a system of reciprocating rods or spears for raising
weights and persons in mines; but I claim,
Firstly, the arrangement of catches attached to the machinery for raising
the carriages or boxes, as above described.
Secondly, I claim the arrangement of catches for lowering the carriages or
boxes, as above described.
Thirdly, I claim the application of stages fixed in the shaft of the mine, on
which the carriages or boxes are supported by catches during the descending
stroke of the raising spears or the ascending stroke of the lowering spears, as
above described.
Fourthly, I claim the arrangement of a system of reciprocating rods or
spears so that the weight may be supported during its ascent or descent by two
or more spears, with the weight placed between them, as above described.
Fifthly, I claim the application of a system of reciprocating rods or spears
carrying platforms turning on axes, and acted upon by tappets, as above
described in reference to Figures 15, 16, and 17.
Sixthly, I claim the application of the arrangement which I have described
under the name of the hydraulic balance, in combination with a system of
reciprocating spears, for raising and lowering weights and persons in mines.
And I also claim the use of the cylinders R and pistons S, in combination with
a system of reciprocating spears for the same purpose, whether such pistons
are worked by water, steam, or air, as above described.
Seventbly, I claim the arrangement of steam engines for putting in motion
a system of reciprocating spears for raising and lowering weights and persons
in mines, in such manner that the length of the stroke of the spears shall be
regulated and their motion reversed by shutting off and then reversing the
supply of steam to the engines, as above described.
Eighthly, I claim as improvements applicable to steam engines generally,

page_text: the arrangement of valve gear, consisting in the combination of the excentric
with the rod Y, Z, grooved plates B, and rod F, H, shewn in Figures 10
and 12.
In witness whereof, I, the said Charles Cowper, have hereunto set my
hand and seal, this Twenty-first day of February, in the year of our 5
Lord One thousand eight hundred and fifty.