IMPROVEMENTS IN ELECTRO-MAGNETIC TIMEKEEPERS
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by John Henry Johnson at the Office
of the Commissioners of Patents, with his Petition, on the 15th February
1862. A communication from abroad by John Henry Koosen, of
Dresden, in the Kingdom of Saxony.
-
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, and of 166, Buchanan Street, in the City of Glasgow, North
Britain, Gentleman, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN ELECTRO-MAGNETIC TIMEKEEPERS," a communication from
abroad by John Henry Koosen, of Dresden, in the Kingdom of Saxony, to be
as follows:-
This Invention relates to a peculiar construction and arrangement of what
the Inventor terms a "galvanic chronometer with centrifugal regulator," and
consists, firstly, of a peculiar construction and arrangement of electro-magnetic
machine for actuating the works of the chronometer, and of which it forms a
part; and, secondly, of a peculiar construction and arrangement of centrifugal
regulator for controlling the speed of the electro-maguetic machine, and so
regulating the movements of the chronometer.
The electro-magnetic machine, as proposed to be applied, is a rotatory one so
constructed and arranged that the accelerating force acts nearly uniformly in
all phases of its rotation and that no intervals of suspension of the acting
power can interfere in any part of the revolution. This is accomplished by
ensuring that the several electro-magnets forming part of the apparatus shall
not be magnetized simultaneously but successively, so that no absolute inter-
Price 8d 1

page_text: ruption of the galvanic current can ever take place, the current being made to
proceed from the coil of one electro-magnet, after the latter has acted upon
the corresponding soft iron bar, directly into the coil of a second electro-
magnet, which begins to act, in a similar manner to the first, on a second soft
iron bar, and so on, thus keeping up a continual rotation. In carrying out
the above conditions it is proposed to employ three electro-magnets placed in
a vertical position and so disposed that their six poles will form points equi-
distant from each other in a horizontal circle, the whole of the poles being in
the same horizontal plane. The wire for the coils should be as thin as
possible, say, from one to two hundredths of an inch in diameter, well covered
with silk and strongly varnished. The ends of the two coils of each electro-
magnet are so connected that the current proceeds through both coils succes-
sively and the two poles receive opposite magnetic polarity. The wires are
further connected with the poles of the galvanic battery in such a manner
that the poles next to each other in the circle of electro-magnets shall have
opposite polarity or be alternately north and south throughout the series.
Immediately above and as close as possible to the poles of the electro-magnets
are two soft iron bars with cylindrical ends, which bars are secured to a
vertical axis or spindle at right angles to each other, so that their four
extremities shall form a rectangle in a perfectly horizontal plane. This axis
or spindle is terminated at its lower end by a steel centre point rotating in a
suitable footstep, also of hard steel, whilst its upper extremity is provided with
a steel spindle working in brass bearings. Immediately below this spindle is
fitted a wheel which transmits the rotation of the spindle, by suitable gearing,
to the hands of the clock or chronometer. A commutator is employed for
regulating the entrance of the current into the different coils consisting of a
ring or disc of wood permanently fixed concentrically to the main axis or
spindle and having twelve plates of silver, strongly gilt, inlaid in its upper
surface with small interstices between the contiguous edges of the several
plates. To the outer edge of each plate is fitted or formed a small hook of
silver wire, to each of which is fastened one end of the wire coils in the order
and succession required by the relative positions of the magnetic poles and
the corresponding poles of the soft iron bars. The other ends of the wire coils
are connected with each other and with one pole of the galvanic battery
permanently. The other pole of the battery conducts the current into the
vertical axis, whence it passes into a brass rod or arm fastened to the axis at
right angles thereto a little above the commutator, a bunch of fine gold wire
being attached to each end of the armor brass rod and sliding over the different
sections of the commutator when the axis, is rotated, thereby leading the

page_text: current into the different coils successively. As the velocity of the rotation
depends upon the intensity of the current it is proposed to adapt to the appa-
ratus a peculiar regulator or governor in order that the velocity may be
independent of the intensity of the current and a uniform motion be
produced.
.
This regulator consists essentially of a steel rod pivotted at its centre of
gravity so as to be in equilibrium upon a steel pin or axis supported in hard
bearings in a imetal ring secured to and encircling the vertical main axis
concentrically. The two ends of the steel rod have screw threads formed upon
them, and on to each is screwed a brass ball capable of adjustment towards or
from the pivotting centre of the steel rod. When the apparatus is at rest
the steel rod remains at an angle of from 30° to 40° with the vertical
axis, but on a rotatory motion being imparted to the main axis the rod, by
reason of centrifugal force, approaches a horizontal position, and it is this
movement which is made to regulate the action of the current upon the coils.
To the lower end of the steel rod is attached a brass wire, the point of which
is tipped with gold or platinum, and rests, when the apparatus is not in
motion, against a plate of platinum secured to the main vertical axis of the
apparatus, but insulated therefrom. To the upper end of the steel rod is
connected, by means of a fine platinum wire, one end of a thin steel blade
spring, the other end of which is secured into the supporting ring of the
regulator, so that the tension of this spring shall always tend to keep the point
of the brass wire against the platinum plate herein-before referred to. This
plate is connected by means of a fine platinum wire with the brass rod or arm
before mentioned revolving above the surface of the commutator. The current
first enters the main vertical axis, passes thence into the brass ring of the
regulator attached thereto along the steel spring and platinum wire into the
steel rod, and from that rod through the brass wire and platinum plate and
into the brass rotating arm, from which it proceeds through the bunches of
gold wire into the different sections of the commutator and passes thence into
the different coils successively and sets the apparatus in motion. Ata certain
proper velocity the centrifugal force of the steel rod with the brass balls will
be exactly counteracted by the tension of the blade spring, but should that
velocity increase in the least degree, the increased centrifugal force so gene-
rated will cause the steel rod to approach nearer to a horizontal position, and
will effect a breaking of the metallic contact between the metal pointand the
platinum plate, when a momentary interruption of the current will take place,
and an instantaneous slackening of the speed will follow, until the decreased
centrifugal action again establishes the contact. For the attainment of greater

page_text: regularity of working it is proposed to employ two steel rods and pairs of balls
in each apparatus, both rods acting equally upon the same platinum plate.
The adjustment of the working of the clock may be effected either by adjusting
the balls on their steel ro ds or by suitably varying the tension of the blade
springs. Compensation for change of temperature is afforded by having the
regulator rods made of steel, whilst the arins which form the contact with the
platinum plate are of brass, the difference in the expansion of these metals
compensating in a great measure any variation arising from change of tem-
perature. For the same purpose strips of platinum and silver soldered
together are fixed to the blade springs and provided with small adjustable
balance weights.
A modification of "Daniell's battery" is employed for the purpose of
ensuring an almost invariable strength of current for a long period of time.
In some cases it is proposed to work two or more such chronometers from
the same or different batteries, the different electro-magnetic machines in
each clock being regulated or controlled in a great measure by the regulator
or governor of the first of the series of clocks, so that their movements may be
perfectly isochronous. For this purpose the ends of the wire coils belonging
to the second clock are so connected with a second commutator on the first
clock that by the rotation of the axis of the latter instrument the current, by
ineans of a bunch of gold wire connected to an arm on the main axis and
sliding over the metallic sections of the second commutator, enters the wire
coils of the second instrument in the same succession andinthesameintervals
as the corresponding coils of the first instrument. In order to insure a
perfect coincidence of rotation however it is found advisable to applyaspecial
commutator also to the second instrument.