Year: 1888

page_text: Date of Application, 4th Feb., 1888
Complete Specification Left, 2nd Nov., 1883
Complete Specification Accepted, 14th Dec., 1888
I, CHARLES SPRATT, of 9 Erlanger Road, New Cross Gate, in the County of Kent,
Electrician, do hereby declare the nature of this invention to be as follows:-
According to this invention a shaft or other moving part of the machine whose
speed is to be indicated in each revolution closes an electric circuit and advances a
counting train one step. The apparatus is so arranged that when the counting has
taken place for a predetermined time, say a minute, the circuit is broken and the
apparatus ceases to record. In this way the revolutions of the machine during that
minute are actually counted. By means of increasing gear, or by having several
contact makers on the shaft the number of revolutions per minute can similarly be
indicated by the actual number of revolutions during a shorter period.
The time measurer of the instrument consists of a metallic disc having one
insulated spot on its periphery. Bearing on this disc is a pin upon one end of a lever,
whose other end carries the armature of an electro magnet and also a contact, maker
in the counting train circuit. Normally the pin is in a notch in the insulated part
of the disc. When the observer wishes to know the speed of the machine he closes
the circuit through the electro magnet which then attracts its armature and lifts the
pin out of the notch. The axis of the disc is connected to a train of clock-work so
constructed as to start itself immediately it is released and to run at a fixed speed
until again stopped. This speed is so arranged that the disc makes one revolution in
the predetermined time (say a minute), and then the pin upon the lever again drops
into its bole and arrests the apparatus. During the time that the disc is turning the
pin rides on its surface and presses the other end of the lever down on to the contact
inaker in the circuit including the counting train and the contact maker on the moving
part of the machine, so that the machine now signals its revolution to the counting
train which are recorded as before described: Any number of counting trains may
be placed in this circuit, so that a single clock-work train may serve for any number
of indicators.
It is convenient to provide a contact maker in the clock starting circuit at each
indicator, and to so arrange it that the action of making the contact brings the
pointers of the counting train back to zero

page_text: Each counting train is driven by an electro magnet in the circuit, opened and closed
by the moving part whose revolutions are to be recorded-each time the circuit is
closed the magnet attracts its armature and by means of a pawl moves a ratchet wheel
one tooth, a retaining pawl being provided to prevent the ratchet wheel from turning
back. I usually provide the counter with three dials-the axes of the three discs
carry toothed wheels which form part of the train-three other wheels.in this train
are mounted upon a pivotted frame in such manner that, by turning the frame about
its pivot, they are moved out of gear with the remainder of the train. When this
has been done the discs are free to be put back to zero; this is done by the contact
maker in the following manner :-
The circuit closed by the contact maker has in it an electro-magnet whose armature
is upon the frame, so that immediately contact is made the train is thrown out of
gear and the discs are freed. The axis of the discs carries cams of a heart shape
which lie in suitably shaped recesses in a plate, pushed to and fro by the frame, being
connected to it by a pin working in a slot. The slot is of such a length that the
motion of the frame does not begin to actuate the sliding plate until the frame has
moved a sufficient distance to throw the train out of gear, the last part of the motion
of the frame then causes the sliding rod to move into contact with the heart shaped
cams which are thereby turned bringing the three dial discs back to zero.
Dated this 3rd day of February 1888.

page_text: 1, CHARLES SPRATT of 9 Erlanger Road New Cross Gate in the County of Kent
Electrician 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 :-
This invention has for its object improvements in speed indicators. The apparatus
is so arranged that it can be made to show at any time when required the speed of
rotation of a steam engine or other machine in connection with which the indicator
may be applied.
is in the immediate
vicinity of the engine or machine the other which I call the "receiver" is in any
place where it may be convenient that the indication should be given.
The indicator is in two parts one which I call the "transmitter
The two parts are connected by electric circuits.
When desired two or more receivers can be used in connection with
transmitter.
one
In the transmitter there is a clock train it is retained by a pawl and it commences
to run when the retaining pawl is lifted, this is done by an electro magnet the circuit
through which is closed by means of a press button in the receiver whenever the
mechanism is required to operate-The clockwork runs for a short time long enough
for the count to be made and is then stopped by the pawl. The clockwork is controlled
by a fan or other regulator and its speed is accurately adjusted, by duly proportioning
the dimensions of the fan.
In the clockwork there is an axis with two cams upon it which when the axis
rotates operate to close gaps in electric circuits connecting the two parts of the
apparatus. One of these circuits I call the counting circuit its duty is to operate
the counting wheels and the other circuit I call the replacing circuit its duty is to
set the counting wheels to zero.
The gap in the replacing circuit is closed by the operation of the cam soon after the
clockwork is started and the setting of the counting wheels to zero is then performed
as hereinafter described. It is not until this operation is completed and the replacing
circuit is again open that the other cam closes the gap in the counting circuit and
keeps it closed during a definite accurately measured interval for example a quarter
of a minute In the counting circuit however there is a second gap which is closed
at intervals by another cam and this cam is on an axis driven by the engine or
machine the speed of which has to be ascertained. This cam may be so made that it
closes and opens the gap four times in each revolution.
The operation of the transmitter is thus as follows:-the observer at the receiver
starts the clockwork by pushing in the press button provided for the purpose-As

page_text: soon as the clockwork commences to run it sends a current of sufficient duration
through the replacing circuit. Then for a given interval (say a quarter of a minute
the apparatus sends a succession of currents (say four for every revolution of th
engine) through the counting circuit. The counting circuit is afterwards held oper
continuously and the clock work is brought to rest. Two alternative courses are
provided for the completion of the counting circuit it passes in one course when the
engine is going ahead and in the other course when the engine is going astern. This
is effected by providing in the transmitter a rocking contact blade, it is fixed upon
a boss through which the axis driven by the engine passes.
the boss and the revolving axis holds the blade against a contact stud and completes
The friction between
the circuit-When the engine is reversed the boss with the blade turns with the axis
through a small angle sufficient to cause the blade to pass from one contact stud to
another.
Provision is made for the automatic winding of the clock work by means of the
engine.
The receiver contains the following parts: the starting key, the counting mechanism,
the mechanism for replacing the counting wheels to zero and the indicator for
showing whether the engine is running ahead or astern-The starting key is a simple
mechanism closing the call circuit when a press button is pushed in. The counting
mechanism comprises an electro magnet in the counting circuit an armature and a
propelment arm operated thereby and driving a ratchet or propelment wheel with
which a counting train is geared. The replacing mechanism comprises an electro
magnet and armature operating a sliding bar which controls the positions of the
counting wheels taking them out of gear with each other and with the driver and
returning them into gear as required. The replacing mechanism also comprises
another electro magnet and armature giving movement to another sliding bar or set
of bars which operates with cams upon the axes of the counting wheels.
are of heart like form but flattened at the base. Each axis has such a cam upon it
These cams
and there is a corresponding bar working with the cam.
lies against the flat of the can the axis is locked at the zero position of the counting
When the edge of the bar
wheel but by the endwise movement of the bar a recess in it is brought opposite to
the cam and the axis is then free to turn.
direction brings the end of the recess against the cam and by its pressure it turns the
The movement of the bar in the opposite
cam until the zero position is reached.
When the replacing current from the transmitter reaches the receiver it first causes
the counting wheels to be thrown out of gear by exciting,
above mentioned and then the armature of this magnet makes a contact which enables
one of the electro magnets
the replacing current also to flow in the coils of the electro magnet which moves the
replacing bars. When the replacing current ceases springs bring back the sliding
bars, the axes of the counting wheels again fall into gear and the recesses in the 4
replacing bars take such positions as to leave the wheels free to turn.
The indicator which shows whether the engine is running ahead or astern consists
of two electro magnets opposite to each other and with an armature between them.
The counting current passes through one or other of these according to the course by
which this current reaches the receiver and then this magnet attracts the armature-
The armature carries a toothed are gearing with a pinion and the axis of the pinion
carries a light dial on which the words "ahead
other of these signs is brought opposite to an aperture in the fixed dial of the
and " astern are written. One or
instrument, according to the position given to the moveable dial.
"
4
In order that my invention may be fully understood and readily carried into effect 5
I will proceed to describe the drawings hereunto annexed.
DRSARIDIAN AN

page_text: said axis and the apparatus for directing the counting current into one or other of
two paths according to the direction of rotation of the axis.
Figure 2 is a plan of the same parts.
Figure 3 is a plan of the portion of the transmitter containing the clockwork, the
starting and stopping electro magnet and parts connected therewith and the cams and
other parts closing a gap in the counting circuit for a pre-arranged time also
the mechanism for closing the replacing circuit at the time when it is required to
operate.
Figure 4 is an elevation of the same with parts removed,
Figure 5 is a plan of part of the clock winding mechanism.
Figure 6 is an elevation of the same.
Figure 7 is a plan and Figure S is an elevation of other parts of the winding
mechanism.
Figure 9 is a front elevation of the receiver with its case removed.
Figure 10 is a side elevation of the same with the case in section.
Figure 11 is a section on the line 11. 11 in Figure 10.
Figure 12 is a side view of the axis of one of the counting wheels with the parts
mounted thereon.
Figure 13 is a front elevation with parts removed it shows particularly the heart.
cam on the axis of the counting wheel and the sliding bar which replaces the axis in
the zero position.
Figure 14 is an elevation of the bars which carry the axes of the counting wheels at
their inner ends.
Figure 15 is an horizontal section of these bars.
Figure 16 shows the bars in another position as they are when holding the wheels
out of gear.
Figure 17 is an elevation showing the face of the receiver and some other parts are
also indicated.
Figure 18 is a section showing the press button and parts in immediate connection
therewith also the magnet by which the counting wheels are taken out of gear.
Figure 19 is a diagram illustrating the general arrangement of the parts and
circuits.
In Figures 1 and 2 a is an axis on which is a small belt pulley it receives a driving
strap passing also around a corresponding pulley on the shaft or axis of the engine or
machine. In the case of a steam engine it is convenient to pass the strap around the
main shaft-a' is a cam on the axis a it operates against a small roller at the
extremity of a spring arm b. The arm is fixed upon a block of vulcanite or other
insulating material and so is also another arm c. The arms and e carry contacts
which are brought together when the cam acts upon the arm band which separato
when the roller drops into the hollows of the cam. Adjusting screws are provided
as the drawing indicates.
The springs and care in the counting circuit and when they are separated the
circuit is open. is a boss of insulating material loose on the axis a it is pressed by
the spring against the side of the cam, a'. The boss carries a blade and this
makes contact with one or other of the studs d³ ³ according to the direction in which
the axis a is running. The blade d is connected with one or other of the springs b
and e and it carries the current which it receives from them to one or other of the
studs . From these studs circuit wires pass to the receiver. A spur wheel a² is
provided on the axis a and a pinion on the axis a gears with it.
When the apparatus
is used with machines running at high velocities the driving pulley is shifted from the
axis a to the axis a³.
In Figures 3 and 4 e is the spring barrel and ex is the fusee of the clockwork. On
the axis of the fusee and driven by it is a wheel with 144 teeth it drives a pinion with
12 teeth and on the same axis with this is another wheel with 144 teeth driving
another pinion with 12 teeth. This latter is on the cam axis of the transmitter.
The cam axis is geared with a fly by a train consisting of a wheel of 120 teeth a
pinion of 10 teeth another wheel of 96 teeth and a pinion of 8 teeth-which last is

page_text: on the axis of the fly. is a disc on the fly axis it is provided with a single tooth
and with this the end of a pawl lever engages-7 is an electro magnet the circuit
through it is closed by the press button in the receiver, it then attracts its armature,
lifts the lever and allows the clock train to start. There is also a lever having its
fulcrum at and this is also lifted by the armature of the electro magnet. It carries
at its end a roller. which is received into a recess in the edge of a disc on the cam
axis These parts serve to relieve the strain which would be thrown on the clock
work if it were stopped only at the fly spindle-The cam axis f has cams fl and f
mounted upon it and these when the axis rotates operate against rollers at the ends of
the spring arms and 2.
When these arms are lifted they make contact with the arms ³× and 2×
respectively. Through k' and 'x the replacing circuit is closed, and this as will be
seen from the form and position of the cam f¹ takes place immediately after the clock
work starts and the contact lasts for a short time only-2 and 2 are not closed
together until the clock work has run for a little time and has attained a steady
velocity. This contact continues for exactly a quarter of a minute or some other
pre-arranged time-During this interval electric impulses pass through the counting
circuit traversing the springs k¹ and k¹.
In Figures 5 and 6 shows an axis which is arranged in line with the fusée of the
clock train. Upon the axis two belt pulleys are mounted to run loosely. They
are driven continuously by two straps one direct and the other crossed. These straps
also pass around the main shaft of the engine or are actuated in other convenient
manner. Each wheel carries a pawl 2 and a spring 73 and the pawl engages with
a corresponding ratchet fast upon the axis -o that the said axis is always driven in
the same direction whichever way the motor turns.
In Figures 7 and 8 m is the end of the fusée axis of the clockwork and m¹ is a
ratchet wheel mounted leosely upon it and clutched with axis so that the wheel m¹
rotates continuously. is a toothed wheel mounted to turn freely upon m, it has 1.20
teeth and gears with an intermediate wheel with 40 teeth which also engages with
another wheel of 40 teeth, fast with a wheel of 48 teeth which gears with the
toothed driving wheel of 144 teeth on the fusée axis. Thus when the clock runs the
wheel n is slowly driven. n'is an arm fixed to the wheel n and it carries the pin n².
m² is an arm fast upon the axis m it carries the pawl m³ and the spring m which
pressing against shoulders on the pawl holds it either in or out of gear. The pin n²
when it comes round acts against the tail m³ of the pawl m³ and strikes it into gear.
Then the fusée axis is carried round with the wheel mi until a rotation is nearly com-
pleted when the tail m³× again comes against the pin 2 but on the other side and the
pawl is thrown out by it. Thus the clock is wound one turn at a time.
In the receiver (see Figures 9. 10. 11. 12. 13. 14. 15. 16. 17) is the electro
magnet which actuates the counting wheels; its armature p' has a propelment arm p²
which operating in the well known manner rotates a propelment wheel ' on an
axis. There is also a ratchet wheel upon the axis and a retaining pawl. 2 is a
spur wheel on the same axis, it engages with and drives a corresponding wheel on the
axis which is the first axis in the counting train. In the counting train there are
three axes and 2 and these are geared together in a 'well known manner so that as
the axis completes its rotation, which it does by ten successive steps, it moves the
axis one step equal to a tenth of a rotation and similarly as the axis completes a
rotation it moves the axis 2 one step.
There is a disc on the axis and against the periphery of this disc projections on
another disc carried by the axis bear so that this axis is locked and cannot turn
until a notch in the disc comes round and allows one of the projections of the axis pl
to pass at the same time also a pin on the disc 7 comes against a tooth on the disc
carried by the axis and so this axis is moved one step and then is again locked.
Similarly the axis 7 locks and propels the axis. *** and *** are the indicating
wheels which these axes carry; one figure on which is visible through an aperture in
the dial of the instrument as is seen in Figure 17. Thus the figures visible on this
dial indicate the number of steps made by the propelment and these correspond to the

page_text: "
rotations of the engine or machine which can be thus counted up to the number
of 999 in the minute.
The axes and 2 at their outer ends are carried by the links sss and at their
inner ends they turn in bushes ttt on the links which bushes are held hetween two
bars u and c. The bar is fixed and might be part of the instrument but the bar
is able to slide to and fro a short distance under the influence of the spring e¹ and the
electro magnet wc. The armature of this magnet is mounted on an axis which is
provided with an arm w¹ and this arm is jointed to the bar c. The bars and are
both provided with elongated holes into which the bushes are received and when
the bar is moved by the magnet it carries the bushes with it but from the arrange-
ment of the slots they are moved different distances. The axes and are moved
with the bushes and so when the magnetic operates all the axes are taken out of gear
and when it ceases to operate they are returned into gear by the spring. When the
arm has taken the wheels out of gear it completes a contact at and then the
electric current is divided between the magnet w and the magnety. The magnet y
has an armature carried by arms on the axis ! on which is also a lever =.
An arc
of teeth on the lever gears with a pinion A and on the same axis with this
pinion there is a toothed wheel A¹ gearing with rack teeth B' on the bar B. In the
bar B there is a recess B and when the axis of the first counting wheel leaves its
zero position the cam C on this axis enters the recess B² which however is of such
dimensions that the rotation of the axis is not interfered with.
.
But when the count having been made, the bar B is moved by the magnet the
shoulder B2x at the end of the recess comes against the cam and the axis being now
out of gear the cam is turned until the axis reaches the zero position. The upper edge
of the bar passes the flat of the cam and the axis is so held as long as the bar retains its
position. When the electric current ceases the two electro inagnets release their
armatures and the axes fall into gear again and are set free. There are other bars B×
and B** attached to the bar B and these operate in a similar manner with heart
cams C on the axes and 2.
DD are two electric magnets through one or other of which the counting current
reaches the receiver and E is the armature which they control; it is upon a lever
which also carries the arc of teeth El gearing with a pinion F' which is upon the same
axis with the moveable dial. on which the words "ahead" and "astern are printed
and as seen in Figure 17 one or other of these words becomes visible through an
aperture in the stationary dial of the receiver. G is the press button which closes
the starting circuit.
Figure 19 is lettered in accordance with the preceding description as far as the
diagrammatic nature of this figure admits.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is :-
1. A speed indicator substantially as described consisting in a transmitter and
receiver connected by electric circuits and comprising clockwork which for a certain
time allows a counting circuit to be completed; a contact maker actuated by the
engine or machine and operating to close and open the counting circuit during the
interval allowed by the clock and more or less frequently in accordance with the speed
of the engine or machine; an electro magnet or electrical mechanism operated by
the closing and opening of the counting circuit counting wheels driven by such
magnet or mechanism and apparatus replacing the counting wheels to the zero position
after use and ready to again operate.
2. A speed indicator substantially as described consisting in a transmitter and
receiver connected by electric circuits and comprising mechanism which for a certain
time allows a counting circuit to be completed; a contact maker actuated by the
engine or machine and operating to close and open the counting circuit; an electro
magnet or equivalent mechanism operated by the closing and opening of the counting

page_text: circuit counting wheels operated by such mechanism; and a circuit closer in the
receiver in circuit with an electro magnet or equivalent mechanism in the transmitter
operating to start the mechanism when its indication is required.
3. The mechanism substantially as described for replacing the counting wheels
consisting of parts which move the wheels into and out of gear with each other and
with the driver; and cams on the axes of the wheels and bars operating in conjunction
with such cans to turn the wheels to the zero positions and to release them when they
have again passed into the zero position.
4. Apparatus substantially as described and represented by the annexed drawings.
Dated this 21st dow of Dotahan 1000
CHARLES SPRATT.