Improvements in Speed Indicators.
Year: 1899

page_text: Improvements in Speed Indicators.
I, WILLIE DICKSON KILROY, of Eastmeon, Pellhurst Road, Ryde, in the Isle
of Wight, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention relates to apparatus for indicating the speed or number of
revolutions or strokes in a unit of time, such as a minute, of engines or machines.
For this purpose, I provide two counters of any known kind, suitable for the
range of speed to be indicated, and I provide suitable clock work which may be
driven by a weight or spring or by remontoir appliances from the engine or
machine to which the indicator is applied. During a unit of time, such as a
minute, one of the counters is in operation, but it is concealed by a shutter or
otherwise, the other counter being stationary and shewing by its dials or indices
the number of revolutions or strokes made during the previous minute.
the minute elapses, the clock-work, by mechanical or electrical connection,
causes the following actions to take place.
When
The counter that had been stationary has its dials or indices moved to zero
is then started and concealed, the counter that had operated during the minute
is disengaged and exposed so that its indications are seen. This is repeated from
minute to minute, one of the counters always shewing what the speed was
during the previous minute.
Dated this 16th dow of Tahmen 1900
ABEL & IMRAY,
Agents for the Applicant.
I, WILLIE DICKSON KILROY, of Eastmeon, Pellhurst Road, Ryde, in the Isle
of Wight, Electrical Engineer, do hereby declare the nature of this invention
and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement:-
My invention relates to apparatus for indicating the speed or number of
revolutions or strokes in a unit of time, such as a minute, of engines or machines.
For this purpose I provide two counters of any known kind, suitable for the
Price &/1

page_text: range of speed to be indicated and I provide suitable clockwork which may be
driven by a weight or spring or by remontoir appliances from the engine or
machine to which the indicator is applied. During a unit of time, such as a
minute, one of the counters is in operation but it is concealed by a shutter or
otherwise, the other counter being stationary, and shewing by its dials or indices
the number of revolutions or strokes made during the previous minute. When
the minute elapses the clockwork, by mechanical Ol' electrical connection
causes the following actions to take place.
The counter that had been stationary has its dials or indices moved to zero
is then started and concealed, the counter that had operated during the minute
is disengaged and exposed so that its indications are seen. This is repeated from
minute to minute, one of the counters always shewing what the speed was
during the previous minute.
In a modification of my invention I provide two counter dials with only
one counting mechanism driven by the machine whose speed is to be indicated;
and I then use gearing adapted to connect the counting mechanism to the figure
dial wheels alternately for equal intervals of time; means being provided for
locking the figure dials which are at rest and exposed, and a device for setting
them to zero immediately before the time when they are to be geared once more
to the counting mechanism.
When my speed indicator is only required to be of small size I may use an
ordinary clock fitted with a specially strong spring drum from which the energy
required to perform the operations of concealing, starting, stopping, locking, expos-
ing, and setting to zero in proper sequence, may be derived; but as a rule I profér
to draw the required energy from the machine whose speed is being indicated
so that the only work that the clock is called upon to do is to bring such energy
into play by means of suitable trigger connections. As an alternative the clock
may close the circuits of electro magnets which provide the required energy.
The energy for the aforesaid sequence of operations may also be derived from
water or other fluid under pressure, acting on pistons in cylinders, the valves
controlling the admission and release of the fluid to and from the cylinders,
being worked by the clock. Any of these means fall within the scope of my
invention and I use one or the other of them according to circumstances; thus,
in indicating the speed of a dynamo, I should prefer to use electric gear con-
trolled by the clock while in indicating the number of strokes per minute
made by a hydraulic engine, small pistons in cylinders can easily be adapted to
perform the sequence of operations required in my speed indicator. Electric
gear has the advantage that where several speed indicators are in use they may
all be controlled by one clock.
In order that my invention may be better understood, I will now describe it
with reference to the accompanying drawings, in which Fig. 1 and Fig. 2 are
respectively a back view and end view partly in section of my speed indicator,
shewing electric means for performing the required sequence of operations. In
these two figures like letters refer to like parts.
Figures 3, 4, 5, 6 and 7 shew my modified speed indicator in which the two
sets of figure dials are driven alternately by one counting mechanism, and in
these drawings I shew means by which the energy for performing the sequence
of operations is derived from the machine whose speed is being indicated. In
these five figures like letters refer to like parts.
Fig. 3 is a back elevation of the counter and clock. Fig. 4 is an elevation
partly sectional of one end. Fig. 5 is an elevation partly sectional of the other
end. Figs. 6 and 7 are part plans.
Fig. 8 is an end elevation of a self-winding clock, adapted for controlling
my speed indicator.
In Fig. 1, U, T and H are the units, tens and hundreds figure wheels of the
first or upper counter; u, t, and h being the figure wheels of the second or lower
counter. The counters shewn are of the ratchet type driven by means of

page_text: pawls P, p attached to a lever L fixed on a rocking shaft A, which is oscillated
through the angle X, indicated by dotted lines, by the machine to which the
indicator is connected. R₁ R and R³ are the retaining pawls of the upper
counter, and 2 and 3 are the retaining pawls of the lower counter. These
pawls are at the proper intervals of time disengaged from the ratchet wheels by
means of the electro magnets Ee whose armatures have arms c¹ and to which
the disengaging bars 61 and 62 are jointed. When the armatures are attracted
by the electromagnets pins on the bars press against the pawls and raise
them simultaneously from the ratchet wheels.
The driving pawls P p are alternately put into gear and released from the two
units ratchet wheels U and u, by means of the two electro magnets Ff whose
armatures I i by means of an arm 3 move a bar B which is jointed to a shorter
arm which is held by a spring S in either of its extreme positions, passing
through a position of unstable equilibrium during its motion from one end of
its extremes to the other. The bar B carries a pin D adapted to disengage the
pawl P and another pin d to disengage the pawl p. By means of lateral teeth
the units disc carries to the tens disc and the tens disc carries to the hundreds.
The axle of each ratchet wheel has a spring device attached to it tending to
cause it to rotate backwards until its figure wheel has come round to zero. This
arrangement is omitted in Fig. 1, but is shewn in Fig. 2, where is a spring
surrounding but not touching the axle I to which the ratchet wheel and figure
wheel are attached. The spring is attached to a slider V which carries a pin x
projecting towards the axle and engaging in a helical groove v cut in the axle J.
The groove makes one complete revolution round the axle and its two ends are
united by a straight groove parallel to the axis. During the time the ratchet
wheel is at work the pin a is being drawn along the groove against the force
of the spring z. As soon as the ratchet wheel has completed one revolution
arrives at the end of the helix and entering the axial part of the groove the
spring instantly pulls the pin to the other end of the helix, further progress
of the ratchet wheel draws c again along the helix against the force of the
spring and this process is repeated at every revolution of the ratchet wheel.
When the counter is at rest and disengaged from the driving pawl, the spring
pulls the axle round the zero as soon as the retaining pawl is lifted from the
ratchet wheel, it being arranged that when the pin is at the beginning of
the helix the counting wheel is at zero.
A shutter moving in guides immediately behind the fixed dial of the counters
is moved up and down alternately by means of arms and 2 of a rocking axle o
which carries a third arm 13 engaging in a notch in the bar B.
The circuits of the four electro magnets are closed in proper sequence by
means of a contact cam K of insulating material, fixed on an axle M worked
by a clockwork C so as to make one revolution in two minutes. The cam
carries a contact Z connected by means of an insulating collar on the axle and
a rubbing contact spring to the electro magnets E, e; a second contact G is
connected through the axle and another rubbing contact spring to the electro
magnets F, f. Contact pawls N, n serve to put Z and G in connection with two
batteries Y, y to which return wires are brought from the electro magnets E, F
and e, f, respectively.
With the various parts in the positions shewn in Fig. 1 and Fig. 2, the engine
whose speed in being indicated is driving the upper counter, having just com-
pleted a forward stroke driving the units ratchet forward one tooth. The pawl p
is disengaged from the lower counter by means of the pin ; this counter is
therefore at rest and is locked in position by means of its retaining pawls l
and 3. The cam K has nearly completed a half revolution since contact was
broken between N and G; when the cam has advanced a little farther n will
drop on to Z closing the circuit. of y through the electro magnet e, thereby
disengaging the retaining pawls from the lower ratchet wheels, each of which
is then turned back to zero by spring z. Contact Z is made of sufficient angular

page_text: length to give the lower counter ample time to come to rest at zero; n then
ceases to make contact with Z, and the circuit of e being thus brkoen, the retain-
ing pawls of the lower counter once more engage in the ratchet wheels.
Immediately after this operation n makes contact with G, closing the circuit
of the battery y through the electro magnet f which attracts its armature i and
so allows p to engage in the units ratchet wheel of the lower counter and at
the same time the pin D lifts the pawl P clear of the units ratchet wheel of the
upper counter. The movement of the bar B lowers the shutter q exposing the
upper counter through the window W and thus indicating the number of strokes
or revolutions made during the previous half revolution of the cam K. At the
same time the other half of the shutter falls behind the window w and conceals
the lower counter, which is now in operation.
When the cam has made another half revolution a similar sequence of events
takes place, the electro magnet E first lifting the retaining pawls of the upper
counter to allow it to come to zero; and the electro-magnet F by attracting its
armature I, disengages p from the lower counter and the pin D allows the driv-
ing pawl P to engage once more in the upper counter.
In Fig. 3 a self-locking counting mechanism is shewn in which the units,
tens, and hundreds wheels are separately driven each by its own driving pawl,
the particular type of mechanism employed being shewn in Fig. 4. As I make
no claim to the interlocking action of the primary counting pawls shewn in
Fig. 4, I do not here more particularly describe it. Each wheel of this count-
ing mechanism is geared through an intermediate wheel, which may be termed
a switch wheel, with a similar toothed wheel attached to one side of the corres-
ponding figure drum. The switch wheels S1, S2, and S3 are mounted loosely
on a fixed spindle R capable of limited longitudinal motion. When R is in
the position shewn in Fig. 3, the switch wheels communicate the motion of the
counting mechanism wheels C1, C2 and C to the gear wheels g³, g² and g³ belong-
ing to the lower figure drums u, t and h; the gear wheels G₁, G² and G³ belong-
ing to the upper figure drums U, T, and H are disengaged and the figure drums
at rest.
The means by which the switch wheels are moved out of gear with one set
of figure drums and put into gear with the other are clearly shewn in Figs. 6
and 7, some portion of the mechanism shewn therein being also shewn in Fig. 3,
the remainder being omitted in that figure to avoid confusion. The switch
wheel axle R is linked by means of a connecting rod to a short crank on the
axle a; this axle carries a cross-arm r adapted to engage in one or other of the
toggles F, f. In the position shewn in Fig. 5, the toggle f is in the same plane
with r and has pushed it into the position which brought the switch wheels into
gear with the lower figure drums. The toggles are rigidly attached to an axle
pivotted in the frame work X of a parallel motion which is continuously oscil-
lated to and fro by means of a crank fixed on the rocking shaft A. The toggle
axle is fitted with a spring s adapted to hold it definitely in one or other of its
two positions, stops against which the toggles abut, being provided on the frame
work X to limit the motion.
The periodical reversal of the toggle axle is brought about by means of a
spiral cam K attached to an axle M which is driven at a uniform speed by
clockwork. For convenience it may be assumed that the cam makes one revolu-
tion in two minutes and each set of figure drums is at work for a period of one
minute and at rest during the succeeding minute.
Two pawls P, p rest on the cam at opposite ends of a diameter; the pawls
carry hinged detents D, d. The detent D is in the plane of the toggle F and
the detent d in the plane of the toggle f, but during the greater part of the revolu-
tion of K the pawls hold the detents clear from the toggles. When the cam is
rotated a few degrees beyond the position in which it is shewn in Fig 5, the pawl P
suddenly drops past the shoulder of the spiral, thereby lowering D until it
gets into the path of the toggle F. When the frame X moves back to the left,

page_text: F meets the detent 1), and turning on its axle is brought to the level of the
cross-arm r, at the same time turning f out of the way; the springs causes this
motion to take place suddenly and definitely. On the next forward movement
of the frame X, Fengages the cross-arm r and carries it and its axle a partly
round, drawing the switch axle R and switch wheels out of gear with the wheels
of the lower figure drums and putting them into gear with those of the upper
drums. It will be noticed on referring to Fig. 4 that this operation takes place
on the return stroke of the rocking shaft during which time the counting
wheels C, C and C³ together with the switch wheels and figure drums are motion-
less, a condition which ensures the teeth of the switch wheels coming opposite
and entering into the spaces in the gear wheels of the figure drums. The same
condition ensures a continuous record of the speed of the machine to which my
indicator is connected for the switch wheels are always in gear with the wheels
of either the lower or the upper figure drums, and since the change from one set
of wheels to the other takes place in the interval between two working strokes
of the counting mechanism the first of these strokes is recorded on the drums
which are just being taken out of gear, and the succeeding working stroke is
the first to be counted on the figure drums, which are being put into gear; thus
it is impossible for my modified indicator to miss counting any revolutoins or
strokes.
The windows in the fixed dial b of the indicator are closed and opened at the
proper moments by the cylindrical shutters E, e. The shutters are raised and
lowered by means of a connecting rod working on a crank fixed on the axle a
so that as soon as the toggle F reverses the position of the cross-arm the shutter E
is lowered and conceals the record of the upper figure drums; at the same time
the lower shutter e descends and exposes the record made by the lower figure
drums during the previous minute.
The means for locking the figure drums when exposed, and for putting them
to zero immediately before they are put into gear with the counting mechanism
are shewn in Fig. 4. Three retaining pawls p' (of which only p¹ appears
in Fig. 4) are attached to an axle a¹ in such positions as to engage respectively
in the gear wheels G G and G3; al projects from the frame work of the indi-
cator and on the outside carries a two armed lever on the arm w¹ of which is
a projecting pin y'. The second arm projects downwards towards a prolonga-
tion of the switch wheel axle R. A spring having its one end attached to wo¹
and its other end to a reciprocating lever J tends to rotate a clockwise or counter
clockwise according to the position of the reciprocating lever. In the position
shewn in Fig. 4 the spring tends to move a clockwise.
A disc L attached to a prolongation of the clock axle M has an annular rib
projecting on its inner face extending over an are which must be greater than
90 degrees and less than 180 degress. In the position shewn in Fig. 4 the
pin y is held within the rib on L, thus retaining we, the axle a¹ and the
retaining pawls attached thereto in position notwithstanding the pull of the
spring. A slight further rotation of L releases y; ¹ is thereupon drawn by
its spring up against the stops thus releasing the retaining pawls from the
gear wheels G1, G2, and G³. At the same time is brought into a position
clear of the path in which the disc V (attached to the switch wheel axle R) moves,
as R is drawn back by the operation of the toggle device already described.
On the disengagement of the retaining pawls the wheels G¹, G³, and G³ and
their corresponding figure drums U, T and H, are brought to zero by the device
shewn in dotted lines in Fig. 4, and partly indicated in Fig. 3. 21, 22 and 23
are projections fixed to the gear wheels; a lever is pressed against each projec-
tion by means of a spring and as soon as the retaining pawls are withdrawn from
the teeth of the gear wheels the force of the springs is sufficient to bring the
figure drums quickly to zero. The projections are triangular in form, the side
adjacent to the axis of the gear wheels being made flat, so that the figure druma
may be held definitely at zero.

page_text: During the time that the counting mechanism has been in gear with the
wheels of the lower set of figure drums, the retaining pawls q' q² and g³ of which
only q appears in Fig. 4 have been locked in the position shewn.in Fig. 4, that
is to say, clear of their corresponding gear wheels, by reason of the lever a²
resting against the periphery of the disc V. As soon as the toggle device already
described begins to move the switch wheels out of gear with g¹ 93 and g³, the
motion of the disc V permits the spring attached to the lever w² to draw that
lever upwards at the same time moving towards the axle R. The consequent
rotation of a draws the retaining pawls q 2 and 3 into the gear wheels and
locks them. This motion of the lever system attached to a² brings the pin y
to a position behind L, at a less distance from the centre of the axle M than the
radius of the annular rib on the inner face of the wheel, L..
.
"
In order that at the next changing of gear between the counting mechanism
and figure drums the retaining pawls may be able to unlock and lock their
respective gear wheels in the reverse order to that just described, it is necessary
to reverse the direction in which the springs I, i pull upon the levers c¹ and w².
These two springs pull on pins which are fixed at one end of two levers J, j,
adapted to be oscillated slowly by means of connecting rods turning on a crank
pin 'n in the disc L. Thus during the revolution of L the pins on J j travel
from one side of the axles a¹ to the other. In the position shown in the
drawing the springs are both pulling upwards, but when the clock has rotated L
and the crank pin n through about a right angle the springs pull in line with
their corresponding axles a¹ a² that is to say they are at the neutral point and
tend to cause no rotation about the said axles; and when Jj have passed the
neutral position both springs begin to pull downwards. The first effect of this
change in the direction of the force on the lever system is to pull w¹ away from
the stop s but the further motion of that lever system is arrested by ¹ coming
in contact with and resting upon the periphery of the disc V.. At the same time
the spring begins to pull the lever system to which it is attached and tries
to rotate the axle a² in a counter-clockwise direction; its motion in this direction
is however arrested by the pin 2 coming in contact with and resting against
the inner surface of the annular rib of L which has been brought round by the
motion of the clock into the required position. During the further motion of
the disc L and crank pin n the springs I i steadily increase their turning moment
about a a² reaching their maximum at the moment when they are called upon
to draw the pawls p¹ 22 and 23 into the upper gear wheels and disengage the
pawls q qand q³ from the lower gear wheels.
The springs I do their work practically instantaneously at the required
moment.
Since the step by step motion of the counting mechanism rotates the figure
drums by steps of one-tenth of a revolution per stroke, it is clear that the num-
ber of teeth in the gear wheels G¹ G3 and G³ and g¹ g² and g³ must be either 10
or a multiple of 10; 20 teeth is a convenient number. The gear wheels C¹. C²
and C3 on the counting mechanism must obviously have the same number of
teeth. In the case of the switch wheels however it is not essential that they
should be either the same size or contain the same number of teeth as the other
gear wheels. It is however generally convenient to make them the same size
so that all toothed wheels used in my modified speed indicator are of the same
size and have the same number of teeth.
The rocking shaft A may be connected to any convenient reciprocating part of
the engine or machine whose speed is to be indicated but I prefer to transmit
motion from the engine or machine to an intermediate shaft in my speed.indi-
cator and by means of a cam fixed on the intermediate shaft cause the rocking
shaft A to oscillate through a fixed angle independent of the angle through which
the intermediate shaft oscillates so that in coupling the speed indicator to the
engine or machine it is not necessary to adjust the stroke of the connecting link
er rod with any great accuracy.

page_text: The clock B of Fig. 3 is shown in more detail in Fig. 8 which illustrates a
suitable self-winding mechanism. The spring drum B is wound by means of
a pawl P engaging in a ratchet R which is fixed to the spring drum axle S.
The winding pawl is pivotted on a lever L which turns loosely on the axle S and
is oscillated to and fro through an angle of about 40 degrees by means of a con-
necting rod C having one end pivotted on L and the other end pivotted on a
crank K which is fixed on the rocking shaft A of the speed indicator. The
retaining pawl p is pivotted on a lever / which turns loosely on S having a
limited movement between the stops a¹ and a². In the position shewn in the
drawing is held against a by means of the spring F.
The operation of this mechanism is as follows:--The oscillation of the lever L
drives the ratchet wheel forward one tooth for each stroke of the rocking shaft;
continually, as it winds up the spring, increasing the back pressure of the ratchet
against the retaining pawl. As soon as this pressure exceeds the strength of F
by a sufficient amount to overcome the additional tension exerted by a second
spring the ratchet pushes back the retaining pawl during the return stroke
of the driving pawl until 7 rests against 2. During this motion the connecting
rod rl has turned round the toggle T, on which it is pivotted until the spring f
has passed through a position of unstable equilibrium and reversed the direction
in which it tends to rotate the toggle. The toggle is connected by a second
rod to a guard sector G. The guard is pivotted loosely on S and its radius is
a little greater than that of the tips of the ratchet teeth. It is pulled into a
nearly vertical position by the motion of the toggle already described. The
driving pawl, which is purposely made wider than the ratchet wheel is no longer
able to drop into the ratchet teeth; thus so long as is resting against a the
driving pawl merely slides to and fro on the periphery of the guard. The clock
is now fully wound, the extent to which it is wound depending on the strength
of the spring F and on the force required to pull the toggle round from the
first position to the second against the force of the spring f
As the clock runs down its driving spring exerts less and less pressure against
the retaining pawl and as soon as the spring is able to overcome the pressure
of the ratchet on the retaining pawl together with the force of the spring f on
the toggle, it suddenly causes the lever to reverse its position and come once
more into contact with a. The guard being now moved out of the way of the
driving pawl, this once more begins to wind the clock.
The amount by which the clock runs down before it is re-wound depends on
the strength of the spring f.
The spring drum B is geared to the axle M already referred to as "the clock
axle" in describing the speed indicator. This axle rotates once in two minutes.
A third axle carrying an escapement has to be geared with M and the escape-
ment axle may be brought through the fixed dial of the indicator and carry a
seconds hand to shew that the clock is working and keeping correct time.
The
gear between the spring and the axle M is shewn in the ratio of 3 to 1 so that
the spring drum makes one revolution in six minutes. This comparatively
rapid rotation of the spring drum permits of a moderately strong spring such as
would ordinarily be used in an eight-day clock to drive the cams and other mech-
anism attached to the shaft M with ease.
Having thus particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is-
A speed indicator comprising two counters, or one counting mechanism with
two sets of indices; gear adapted to alternately start and stop each counter or
each set of indices at equal intervals of time; shutters for concealing each of
the two sets of indices, while it is moving devices for locking each during its
periods of rest means for setting each to zero; and a clock adapted to work or

page_text: control the said gear, shutters, devices and means for starting, concealing, stop-
ping, locking, exposing, and setting to zero in proper sequence at pre-arranged
instants and for definite intervals of time, substantially as described.
Dated this 15th day of December 1800
ABEL & IMRAY,
Agents for the Applicant.