IMPROVEMENTS IN MACHINERY OR APPARAtus por INDICATING THE NUMBER OF REVOLUTIONS PER MINUTE MADE BY A ROTATING SHAFT
Year: 1874

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine,
Lake, & Co., Patent Agents, Southampton Buildings, London,
for the Invention of "IMPROVEMENTS IN MACHINERY OR APPARAtus por
INDICATING THE NUMBER OF REVOLUTIONS PER MINUTE MADE BY A ROTATING
SHAFT." A communication from abroad by Edward Brown, of
Dhiladelphia Donnsylvania Tinited States of America.
PROVISIONAL SPECIFICATION left by the said William Robert Lake
at the Office of the Commissioners of Patents, with his Petition,
on the 23rd April 1874.
I, WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co.,
Patent Agents, Southampton Buildings, London, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN MACHINERY OR APPARATUS
FOR INDICATING THE NUMBER OF REVOLUTIONS PER MINUTE MADE BY A. ROTATING
SHAFT," a communication, to be as follows:-
My Invention consists first in combining a wheel rotating at regular ·
intervals by clock movement with two sets of counting registers. The
friction wheel or ratchet which actuates the registers is transferred by a
:

page_text: suitable escapement alternately from one counting register to the other.
The registers are released and reset themselves by self-acting mechanism
at the end of every minute. The two registers, actuated by a pawl as is
common with counting registers, are placed close together, so that the
pawl may be transferred instantly from one register to the other. This
pawl is placed at the end of a vibrating lever, which is vibrated at fixed
intervals of time by means of the clock wheel. This clock wheel has in
its periphery two cam notches into which a knife edge on a lever falls,
and is kept in contact therewith by a spring. There is a tappet on the
clock wheel which presses alternately against the two sides of a spring
fork at the end of the vibrating lever for the purpose of vibrating it as
soon as the end of the lever is released by the knife edge falling into the
notch on the clock wheel, thus giving to the lever a sudden vibrating
motion at fixed intervals of time. Another tappet on the clock wheel
raises a pawl from the registering wheel just before the minute is up,
and then the registering wheel is returned by a spring to its normal
position at 0 or zero; this takes place the instant before the vibrating
lever moves the ratchet.
Instead of returning the register wheels by a spring, the levers which
I have spoken of as actuating the pawl may carry a friction wheel moved
by the machinery whose speed is to be indicated. The bringing of
this wheel into contact with the registering wheel will return it to its
normal position at 0 or zero.
Secondly, I accomplish this result by the rotation of a cup containing
mercury, the centrifugal force of which depresses the central portion of
the fluid. A glass tube with the lower end enlarged is filled with colored
water and inserted in the mercury, and held there by the lid of the cup.
There are ribs or bars cast inside the cup which cause the motion of the
cup to be communicated instantly to the mercury. The depression of
the central portion of the mercury due to centrifugal force is shown in
an increased degree by the fluctuation of the water in the tube. A scale.
at the back of the tube shows the revolutions per minute due to each
variation in speed.
In order to make this instrument available for the use of a column of
mercury in the central glass tube I secure the glass tube to the cup by a
stuffing box, and screw an iron pipe into the cup, which is elevated
above the cup and revolves around the central glass tube. Mercury

page_text: being poured into the iron tube it will rise to the same level in the glass
tube, and on rotating the instrument the fall of the mercury in the
glass tube will indicate on a scale the revolutions per minute.
The upper part of the iron tube is enlarged, so that a great fall in the
glass tube will not require much additional height to the iron tube.
And to prevent the mercury flying out of the top of the iron tube by a
sudden spurt common to marine engines I return the top of the iron
pipe inward towards the centre.
To compensate for the inaccuracy which would occur on a steamer
from the rolling of the vessel a pendulum weight is fixed at the back
of the scale which communicates its motion by suitable leverage to
lower the scale according to the angle of inclination of the vessel,
•
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Robert Lake in the Great Seal Patent
Office on the 20th July 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of April, in the year
of our Lord One thousand eight hundred and seventy-four, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Robert Lake, Her special
licence that I, the said William Robert Lake, my executors, adminis-
trators, and assigns, or such others as I, the said William Robert Lake,
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
"IMPROVEMENTS IN MACHINERY OR APPARATUS FOR INDICATING THE NUMBER
OF REVOLUTIONS PER MINUTE MADE BY A ROTATING SHAFT," a communication
to me from abroad by Edward Brown, of Philadelphia, Pennsylvania,
United States of America, upon the condition (amongst others) that

page_text: I, the said William Robert Lake, 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 William Robert Lake, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the accompanying
Drawing forming a part of this Specification:-
The said Invention consists first in combining a wheel rotating at
regular intervals by clock movement with two sets of counting registers.
The friction wheel or ratchet which actuates the registers is transferred
by a suitable escapement alternately from one counting register to the
other. The registers are released and reset themselves by self-acting
mechanism at the end of every minute. The two registers, actuated by
a pawl as usual with counting registers, are placed close together so that
the pawl may be transferred instantly from one register to the other.
This pawl is placed at the end of a vibrating lever, which is vibrated at
fixed intervals of time by means of the clock wheel. This clock wheel
has in its periphery two cam notches, into which a knife-edge on a lever
falls, and is kept in contact therewith by a spring. There is a tappet on
the clock wheel which presses alternately against the two sides of a spring
fork at the end of the vibrating lever for the purpose of vibrating it as
soon as the end of the lever is released by the knife-edge falling into the
notch on the clock wheel, thus giving to the lever a sudden vibrating
motion at fixed intervals of time. Another tappet on the clock wheel
raises a pawl from the registering wheel just before the minute is up,
and then the registering wheel is returned by a spring to its normal
position; this action takes place the instant before the vibrating lever
I moves the ratchet.
Instead of returning the register wheels by a spring the levers which
I have spoken of as actuating the pawl may carry a friction whee] moved
by the machinery to be indicated; the bringing of this wheel into
contact with the registering wheel will return it to its normal
position.

page_text: Or I accomplish this result by the rotation of a cup containing
mercury, the centrifugal force of which depresses the central portion of
the fluid. A glass tube with the lower end enlarged is filled with colored
water and inverted in the mercury, and held there by the lid of the cup.
There are ribs or bars cast inside the cup and which cause the motion of
the cup to be communicated instantly to the mercury. The depression
of the central portion of the mercury due to centrifugal force is shown in
an increased degree by the fluctuations per minute due to each variation
in speed.
In order to make this instrument available for the use of a column of
mercury in the central glass tube I secure the said glass tube to the cup
by a stuffing box, and screw into the cup an iron pipe, which is elevated
above the cup and revolves around the central glass tube. Mercury
being poured into the iron tube it will rise to the same level in the said
glass tube, and on rotating the instrument the fall of the mercury in the
glass tube will indicate on a scale the revolutions per minute.
The upper end of the iron tube is enlarged, so that a great fall in the
glass tube will not require much additional height to the iron tubc.
And to prevent the flying out of the mercury from the top of the iron
tube by a sudden spurt common to marine engines I return the top of the
iron pipe inward toward the centre.
To compensate for the inaccuracy which would occur on steamers from
the rolling of the vessel a pendulum weight is fixed at the back of the
scale, which communicates its motion by suitable leverage to lower the
scale according to the angle of inclination of the vessel.
The first part of the said Invention relating to indicating the number
of revolutions by means of a clock movement is illustrated in Figures 1, 2,
3 and 4, similar letters in each of these four Figures referring to the same
parts.
A is the wheel of a clock rotating in two minutes or other fixed
interval of time, and having its motion altogether independent of the
other mechanism. On the edge of this wheel are two indentations a¹, a²,
exactly at opposite sides; the indentations are abrupt on one side, and
rise gradually with a curve on the other. Beneath this wheel is a
lever B, pivoted at one end, and forced upward in contact with the
whcel A by a spring c at the other end. In the centre of this arm or
lever B is a double knife edge e projecting above and below the

page_text: lever, the upper side engaging with the wheel A, the lower side engaging
with the vibrating arm D. The arm D is pivoted at its centre on the
pin its lower end carries a shaft g, which receives its motion from
the engine. Upon the end of this shaft is placed a ring of india-
rubber m to give a yielding pressure upon the registering wheels E, H.
Two spring bars N, K, arċ rivetted to the arm D; they pass upward at
the rear of the disc wheel A.
The registering wheel E, having numbers placed around its periphery,
turns freely on a centre pin. A pin 2 projecting from this wheel at the
rear acts as a stop to keep the figure 0 always at the bottom when the
wheel is liberated to find its own position. H is a similar registering
wheel placed about one-sixteenth of an inch from the india-rubber friction
wheel m.
P is a double arm lever; its lower arm acts as a pawl, which
falls into holes in the wheel E. It is moved at the proper instant of
time by the pin a' projecting from the front of the wheel A. A similar
double arm lever R operates the wheel H.
Instead of resetting the registers by springs I mount a friction
wheel W, scc Figure 4, upon the arm of the lever or pawl P. The
wheel X is driven constantly at a high speed by the engine, and by
bringing the friction wheel W in contact with the wheels E and X the
register E is immediately reset to 0.
The clock being set in motion the wheel A rotates once in two
minutes. When it has arrived at the position shown the lower knife
edge e is depressed so as to hold the friction wheel m against the wheel E,
in which position it remains until the notch a arrives at the knife edge e.
At this instant the pin a³ which projects at the front and rear of the
wheel A puts a tension upon the spring bar K, so that when the knife
edge falls into the notch a² the friction pulley m is forced over in contact
with the wheel H, and then the knife-edge descends again on the other
side of the arm D; thus the arm vibrates suddenly from one side to the
other at fixed intervals of time.
Now supposing a rotating motion to be given to the wheel m by the
engine whilst this wheel is in contact with the register E, the said
register will continue to count until the wheel m is released from contact.
When this takes place the pawl P holds the register in position, and the
pointer p' shows the number of revolutions made during the last minute
the other register H is counting while E is stationary. The instant

page_text: before the minute is up the pin a³ projecting at the front of wheel A
operates the pawl P and liberates the register E, which is returned by a
hair spring S to its first position, with 0 at the bottom opposite the
pointer p'.
It is not essential that the arm D shall be vibrated once cach minute.
If vibrated once cach half minute and the register is made to count two
every revolutions of the engine this would give the revolutions per
minute at every half minute interval.
In carrying my Invention into practise I do not confine myself to one
registering whicel, as shown in Figure 1, but where speed is great I use
a train of two or more wheels, as is common with counting registers at
present in use, see Figure 2.
Where the movement of the engine or rotating shaft is passed to the
instrument by a reciprocating motion I use a bell crank T and a double
pawl, as shown at Figure 3.
The second part of the said Invention, in which the centrifugal force
of mercury is employed, is illustrated in Figures 5 and 6.
A is an iron cup cast with ribs B inside. This cup is mounted on a
shaft C in suitable bearings D. A pulley E upon the said shaft transmits
the motion of the engine to the instrument. G is the lid of the cup
screwed on. A central hole is made in the lid in which a ring of india-
rubber is fitted, and another small hole is made at h for the admission of
air. The glass tube K is inserted from the under side of the lid through
the india-rubber ring, and projects above the lid from six to twelve
inches or more. This glass tube is enlarged at its lower end m, and its
enlargement dips into the mercury and forms a seal therewith to prevent
the colored water in the tube from falling out. As soon as the instru-
ment is put in motion the surface of the mercury assumes a hollow form,
and the fall of the water in the tube indicates upon the scale N the
velocity per minute. By the enlargement ma slight fall of the mercury
gives a much greater motion to the column in the tube.
The third part of the said Invention, in which the rise and fall of a
column of mercury in the glass tube is made to indicate the velocity per
minute, is illustrated in Figures 7, 8, 9, 10, 11, 12, 13.
A is a hollow iron casting; B is a bent iron pipe screwed into the
casting A; C is a shaft screwed into the casting A, and turning in

page_text: register accurately at 20 or 30 degrees inclination for any fixed number
of revolutions.
All that is required to complete the instrument after it is fixed is to
pour mercury down the hole into the pipe B (until it stands in the
glass tube at the height indicating 0) and to set the engine in motion.
The mercury will fall in the glass tube according to the velocity of
rotation.
0
Figure 13 shows the instrument fixed to the shaft of a governor. The
scale is omitted here, and in its place an india-rubber ring * indicates the
speed at which the engine is desired to run.
Figure 12 shows a convenient mode of applying the said instrument
to a steam engine by making it a part of the governor. In this arrange-
ment one of the slotted arms W, which usually guide and propel the
governor balls, is made hollow for the reception of mercury, and is in
communication with the glass tube H. The arms W join at the top and
support the governor balls from the hinge T.
Having thus fully described the said Invention, as communicated to
me by my foreign correspondent, and the manner of performing the
same, I wish it understood that I claim,-
First. The wheel A rotating by clock movement and operating by
means of suitable intermediate mechanism to change the motion of a
steam engine from one set of counting registers to the other, as herein
set forth.
Second. The means herein described for communicating the motion of
the wheel A to the counting registers H, E, also the mode of releasing
and resetting the counting registers.
Third. Casting the ribs B or equivalent devices upon the cup A for
the purpose of communicating the accelerating or retarding motion of
the engine instantly to the body of mercury, as and for the purpose
described.
Fourth. The pipe B rotating around the glass tube H, as herein set
forth and for the purpose described.
Fifth. The pipe B with the enlargement R arranged to rotate around
the glass tube H, as herein set forth and for the purpose described,

page_text: Sixth. The combination of the pipe B, the casting A, the glass
tube H, and the steadying arm M, arranged and operating as herein
described.
Seventh. The pendulum S operating in conjunction with the scale N,
as herein described.
Eighth. The enlargement R curved inward at the top and the short
horizontal piece F, as herein described.
Ninth. The adjusting screw K³, operating as herein set forth.
Tenth. The hollow rotating arm W and the glass tube H, as shewn in
Figure 12, combined and operating in a steam engine governor and
forming a part thereof, as herein set forth and for the purpose
described.
In witness whereof, I, the said William Robert Lake, have here-
unto set my hand and seal, this Eighteenth day of July, in the
year of our Lord One thousand eight hundred and seventy-
four.
Tenth. The hollow rotating arm W and the glass tube H, as shewn in
Figure 12, combined and operating in a steam engine governor and 1
forming a part thereof, as herein set forth and for the purpose
described.
In witness whereof, I, the said William Robert Lake, have here-
unto set my hand and seal, this Eighteenth day of July, in the
year of our Lord One thousand eight hundred and seventy- 1
four.
Witness,
HENRY J. NOONE,
8, Southampton Buildings,
London.
W*. ROB³. LAKE. (L.S.)