Improvements in Instruments for Indicating and Registering the Speed of Shafts Rotating at a Distance from the said Instruments.
Year: 1887

page_text: Date of Application, 14th Oct., 1887
Complete Specification Left, 16th July, 1888
Complete Specification Accepted, 24th Aug., 1888
Improvements in Instruments for Indicating and Registering the
Speed of Shafts Rotating at a Distance from the said Instruments.
1, PHILIP CARDEW, Captain in Her Majesty's Corps of Royal Engineers, of Brompton
Barracks, Chatham, do hereby declare the nature of this invention to be as
follows:-
This invention relates to improvements in instruments for indicating and registering
the speed of a rotating shaft, and has for its object the provision of means whereby
such indicating and registering of the speed may be effected at any distance from the
shaft, the invention being also applicable, if desired, to registering the speed and the
variations thereof during any interval of time, or it may be employed to register
the total number of revolutions that have taken place during any interval of time.
The invention is based upon the principle of an alternating current dynamo-electric
generator (of any known type) necessarily transmitting to the external conductor a
number of alternations per unit of time, strictly proportional to the speed at which it
is rotated. It therefore follows that if such a dynamo be connected to a receiving
instrument which causes a shaft to rotate at a speed proportional to the number of
alternations it receives per unit of time, and if this shaft be connected to a speed
indicator of a suitable pattern-the speed indicator will indicate a speed equal to, or
proportional with, that of the alternating current dynamo or of the revolving shaft to
which it is connected.
The transmitting portion of the apparatus consists of an alternating current dynamo-
electric generator, preferably fitted with permanent magnets, which will not require
an exciting current to be supplied to them, while the receiving portion consists,
partly, of a suitable speed indicator (Dr. Horn's Magnetic Speed Indicator being
specially suitable) and, partly, of an instrument to which the speed indicator is attached,
and which causes it to rotate at a speed equal to, or proportional with, that of the
shaft whose speed is to be indicated.

page_text: This instrument is, in some cases, a small alternating current motor, electrically
connected to the transmitter, while in other cases, and where the apparatus is required
to work with a minimum of power, a clock work mechanism, having an anchor escape-
ment similar to that of an ordinary clock, is used to drive the shaft of the speed
indicator.
On the same axle that the anchor of the clock escapement is fixed to, is also fixed,
at, or near, its centre of gravity, the armature of a small polarised electro-magnet
similar to that used for ringing an alternating current bell.
The electro magnet is connected to the line and receives impulses from the trans-
mitting dynamo, which in this case will generally be of the simple type used for
alternating current bell ring, i.e. an old pattern Siemen's armature with one coil
revolved between the poles of a magnet.
The armature of the electro-magnet vibrating to these impulses will thus regulate
the speed of the escapement to proportionality with that of the shaft driving the
transmitter, the clock work being driven by a weight or a coiled spring, and if required
wound up electrically or a small electric motor may be used to drive the speed
indicator, supplied from any available source of power and having its speed governed
by the escapement and electro magnet as described above.
The electric resistances of the transmitter and receiver are proportioned to the
length and resistance of the line it is intended to work through as is well understood.
When the receiving apparatus is required to register the speed and variations thereof
a small pulley is mounted upon the same axle as the indicating needle, which in this case
may be retained or dispensed with as desired, and the deflection of this pulley, which
is proportional to the speed of revolution, causes a small chain, or cord, to be more or
less wound up, the other end of the chain or cord being attached to a pencil point
which slides up and down a support in the usual way and draws a curve on a strip of
paper, caused, by clock work, to advance at an uniform rate in a direction at right
angles to that of the motion of the pencil as is well understood.
Should a record of the total number of revolutions be required it is obtained by
attaching a counter, of any of the usual patterns, to the shaft of the receiver in such
a way as to cause it to be rotated at a speed equal to that of the shaft whose total
number of rotations it is required to show. Where very slow speeds of rotation are
required to be indicated it may at times be desirable to modify the transmitter so that
its motion may be of an intermitting character the speed at each impulse being
constant, but the interval between each impulse varying with the speed of rotation of
the shaft.
This can be readily accomplished by causing the shaft during part of its rotation
to compress, extend, or bend, a suitable spring which at a certain point in the rotation
is released and actuates the transmitting dynamo. A simple form of cam attached to
the rotating shaft will conveniently effect this.
Dated this 14th day of Ontaha. 1007

page_text: Improvements in Instruments for Indicating and Registering the
Speed of Shafts Rotating at a Distance from the said Instruments.
I, PHILIP CARDEW, Captain in Her Majesty's Corps of Royal Engineers, of
Brompton Barracks, Chatham, 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 relates to improvements in instruments for indicating and regis-
tering the speed of a rotating shaft, and has for its object the provision of means
whereby such indicating and registering of the speed may be effected at any distance
from the shaft, the invention being also, applicable, if desired, to registering the speed
and the variations thereof during any interval of time, or it may be employed to
register. or record, the total number of revolutions that have taken place during any
interval of time.
The invention is based upon the principle of an alternating current dynamo electric,
or magneto-electric generator (of any known type) necessarily transmitting to the
external circuit, or conductor, a number of alternations per unit of time strictly
proportional to the speed at which it is rotated.
It therefore follows that if such a generator be electrically connected to a receiving
instrument which causes a shaft to rotate at a speed proportional to the number of
alternations it receives per unit of time, and if this shaft be connected to a speed
indicator, of a suitable pattern-the speed indicator will indicate a speed equal to, or
proportional with, that of the alternating current generator or of the revolving shaft
to which it is by belt, or otherwise, connected.
The transmitting portion of the apparatus consists of an alternating current electric
generator, preferably fitted with permanent magnets which will not require an
exciting current to be supplied to them, and connected to the rotating shaft, whose
speed it is desired to indicate, by means of a belt and pulleys, or otherwise, so as to
ensure its rotating at a speed proportional to that of the shaft; while the receiving
portion consists, partly, of a suitable speed indicator, or instrument showing the speed
of rotation by the movement of a hand, or pointer, before a suitably graduated dial,
any of the well known forms such as Young's, Buss's, or Horn's being suitable; and
partly of an instrument to which the speed indicator is attached, and which causes it
to rotate at a speed equal to, or proportional with, that of the shaft whose speed is to
he indicated.
This instrument is, in some cases, a small alternating current motor, electrically
connected to the transmitter, while in other cases, and where the apparatus is required

page_text: to work with a minimum of power, a clock work mechanism, having an anchor
escapement similar to that of an ordinary clock, is used to drive the shaft of the speed
indicator.
On the same axle that the anchor of the clock escapement is fixed to, is also fixed,
at or near its centre of gravity, the armature of a small polarised electro-magnet
similar to that used for ringing an alternating current bell.
The electro magnet is connected to the line and receives impulses from the
transmitting generator which in this case will generally be of the simple type used
for alternating current bell ringing, i.e. an old pattern Siemen's armature with one
coil revolved between the poles of a magnet. The armature of the electro magnet
vibrating to these impulses will thus regulate the speed of the escapement to pro-
portionality with that of the shaft driving the transmitter, the clock work being
driven by a weight, or a coiled spring, and, if required, wound up electrically; or a
small electro motor may be used to drive the speed indicator, supplied from any
available source of power, and having its speed governed by the escapement and
electro magnet as described above; or a clock work movement may be geared to the
small alternating current motor driving the speed measurer so as to supply the
requisite power while the motor acts as a governor and keeps the speed proportional
to that of the transmitter.
The electric resistances of the transmitter and receiver are proportioned to the
length and resistance of the line it is intended to work through as is well under-
stood. When the receiving apparatus is required to permanently register, or record,
the speed and variations thereof, a small pulley is mounted upon the same axle as
the indicating needle, which in this case may either be retained or dispensed with as
desired, and the deflection of this pulley, which is proportional to the speed of revo-
lution, causes a small chain, or cord, to be more or less wound up in opposition to a
spring or weight suitably attached to the chain, or cord. The other end of the chain,
or cord, is attached to a pencil point which slides up, or down, a support in the usual
way, and draws a curve on a strip of paper, caused by cluck work to advance at an
uniform rate in a direction at right angles to that of the motion of the pencil, as is
well understood.
Should a record of the total number of revolutions be required it is obtained by
attaching a counter, of any of the usual patterns, to the shaft of the receiver in such
a way as to cause it to be rotated at a speed equal to that of the prime mover, or shaft,
whose total number of rotations it is required to show.
Where very slow speeds of rotation are required to be indicated it may at times be
desirable to modify the transmitter so that its motion may be of an intermitting
character, the speed at each impulse being constant, but the interval between each
impulse varying with the speed of rotation of the shaft.
This can be readily accomplished by causing the shaft during part of its rotation
to compress, extend, or bend, a suitable spring, which, at a certain point in the
rotation, is released and actuates the transmitting dynamo, or other generator.
A simple form of cam, or other suitable device, may be attached to the rotating
shaft to effect this.
In the accompanying drawing the figure shows, diagrammatically, the method of
carrying my invention into effect.
The prime mover, or shaft, S, whose rotations it is desired to show, or record,
imparts motion to the pulley P₁ of the transmitter T by the belt B, B, and pulley P,
or other suitable gearing.
The current from the transmitter T is conveyed by the line L, L, earthed, as shown,
at E, E, to the receiver R, whose shaft in turn imparts motion to any suitable form
of speed indicator I, the needle N of which moves before a suitably graduated dial,
or to any suitable form of counter as hereinbefore described, or as is obvious to both
indicator and counter.
As the various apparatus employed in carrying out my invention are all well
known, and as several different types, or patterns, of each are suitable for the purpose,
no further detailed description or drawings of the same are here necessary.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
First. The herein before described method of employing the combination of an
alternating current dynamo-electric, or magneto-electric, generator, geared to the
prime mover, or shaft, whose speed of rotation, or total number of revolutions, it is
desired to show, or record, as a transmitting instrument, and an alternating current
electro-motor driving an ordinary speed indicator, or counter, as a receiving
instrument, in the manner substantially as hereinbefore described.
Second. The employment in conjunction with the arrangement above set forth of a
clock work device, or small electro-motor to drive, or aid in driving, the recording
instrument, in the manner substantially as herein before described.
F. SEATON SNOWDON,
Agent for the Applicant.