IMPROVEMENTS IN ELECTRIC TELEGRAPH APPARATUS
Year: 1867

page_text: LETTERS PATENT to William Robert Lake, of the "International Patent
Office," No. 8, Southampton Buildings, Chancery Lane, in the County of
Middlesex, Consulting Engineer, for the Invention of "IMPROVEMENTS
IN ELECTRIC TELEGRAPH APPARATUS."-A cominunication from abroad by
Elisha Gray, of Oberlin, Ohio, United States of America.
Sealed the 3rd December 1867, and dated the 12th October 1867.
COMPLETE SPECIFICATION filed by the said William Robert Lake at the
Office of the Commissioners of Patents, with his Petition and Decla-
ration, on the 12th October 1867, pursuant to the 9th Section of the
Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the "International Patent Office," No. 8, Southampton
Buildings, Chancery Lane, in the County of Middlesex, Consulting Engineer,
send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
ELECTRIC TELEGRAPH APPARATUS," and have petitioned Her Majesty to grant
unto me, my executors, administrators, and assigns, Her Royal Letters
Patent for the same, and have made solemn Declaration that it has been
communicated to me from abroad by Elisha Gray, of Oberlin, Ohio, United
States of America.
NOW KNOW YE, that I, the said William Robert Lake, do bereby declare
that the following Complete Specification, under my hand and seal, fully

page_text: describes and ascertains the nature of the said Invention, and in what manner
the same is to be performed, in and by the following statement, reference being
had to the accompanying Drawings making a part of this Specification:-
In order to fully understand the nature of this Invention, its application,
and great advantage, a brief statement will be made of the peculiar difficulties
incident to the machines now in general use, and which this apparatus is
intended to supersede. The relay now in use consists of an electro-magnet so
arranged on a base that its poles come near a soft iron armature which is
attached to an upright brass lever hinged to the said base. This armature is
held away from the magnets when no current is passing by a spring attached
to an adjusting screw by which its tension is regulated. When the circuit is
closed the iron of the electro-magnet attracts the soft iron armature sufficiently
to overcome the resistance of the spring and bring it near to the poles. When
the circuit is broken the core magnet immediately becomes demagnetized to a
certain extent and the spring draws the armature away. Although a large
portion of the magnetism is discharged immediately on the opening of the
circuit there is yet another quantity called residual magnetism, that requires
an appreciable time to discharge itself. This would not be a serious difficulty if
the electric current was not variable, but owing to escapes and atmospheric
influences the current is almost constantly changing, more especially in wet
weather. The amount of residual magnetism remaining in the magnet after
the circuit is broken is always in proportion to the strength of the current
which has just passed around it, that is, if the current is strong the residual
magnetism is strong in proportion, and vice versa. Suppose the current to be
very weak the magnetism will be but feebly developed, and consequently the
tension of the adjusting spring must be diminished in order that the armature
may move the next instant the current may be so strong that the residual
magnetism bas power enough to overcome the weak spring of the adjustment
and prevent the backward stroke of the armature until the tension is increased,
and thus with every change of the current there must be a corresponding
change of the adjusting spring. In order to obviate this difficulty and cause
the relay to act freely and independently of the residual magnetism this self-
adjusting or automatic relay is introduced.
DESCRIPTION OF THE DRAWINGS.
Figure 1, Plate 1, is a top view of my improved relay apparatus; Figure 2
is a side view of the said apparatus; Figure 3 is an end view of the same;
Figure 4 is a top view of the key; Figure 5 is a side view of the said key.
Figure 6 Platoo i
ירז

page_text: and Figure 8 an end view of the same; Figure 9 is a vertical transverse section
of the said pole changer; Figure 10 represents a detached portion ofthe same.
Plate 3 is a diagram illustrating the operation of my improvements. Like
letters refer to the same parts in the several Figures.
A is a base upon which is mounted the relay B which consists of two pairs
of helices C, D, constructed in the ordinary way with insulated wires wound
upon spools E provided with core magnets F, F. The helices in each pair
are connected to each other and supported by bars G and are provided with
adjusting screws in the usual manner; J is the permanent magnet armature
mounted on a horizontal axis with two pivots in the stay I upon which it
vibrates by the attractive and repelling power of the core magnets F, F¹³,
exerted upon the horseshoe or permanent magnet J fixed to the lower end of
the armature; each limb of this magnet projects up between the two core
magnets F, F, arrange respectively on each side of the armature and is
operated by the same, as will hereafter be shown. At the extreme lower end
of the armature is attached a spring K, Figure 2, the extremities of which
reach under the adjusting screws L', L", arranged in the stays M, to which
screws reference will hereafter be made.
The practical operation of my improved relay apparatus is as follows:-Tho
said relay is placed in the main office at the lino terminus and is operated on
the same principle as the others on the line, and is in every respect the same
with the addition of its connections with the local batteries, which assist in
operating the "pole changer," hereafter described. The connections of the
relay magnets F, F¹, are so made that their polarity will be in opposite
directions. The permanent magnet armature J which supersedes the ordinary
soft iron armature is placed between the poles of the magnets F, F, and its
operation depends on the principle that like poles repel and unlike attract
each other; thus, if F, J, are both north poles F will have a south polarity,
and hence the force of the three magnets F, J, and F, is exerted to move the
armature H in one direction, F and J acting by their attractive force and
F, J, by the force of repulsion. Now it is evident that if the polarity of the
magnets F, F, is changed the direction of the armature will be reversed, i. c.
the combined force of the three magnets will be exerted in the opposite
direction to that above instanced. This change of polarity is effected by
reversing the current by means of a "pole changer" which will now be
described. The said pole changer consists of two pairs of helical magnets
A', B', Figure 6, Plate 2, arranged in like manner to those of the relay above
described. Immediately under the poles of these magnets A', B', is placed in
a vertical position a pair of helical magnets C', Figure 10. A vertical section

page_text: of the same is shown in Figure 9, in which C' indicates the helices and D¹
the core magnet of soft iron. The latter is similar to an ordinary core except
that it is less in diameter by about three thirty-seconds of an inch than the
opening in the belix to allow a vibratory movement of the said magnet, which
is pivoted in the stay E¹ on a horizontal axis F". These magnets project
through the helices far enough to bring their poles between the poles of the
magnets A, B'. The upper ends of the cores are connected by a brass bar
G', Figure 10, from which projects a screw H¹ on whose end is a plate of
gutta percba I; on this plate are secured the pole-changing points J' and J",
Figure 6, and the current changing points K'. It will be seen that the
pole-changing points J' are connected to the current-changing points K', and
through them to each other by a wire I. The points J" are connected by a
wire under the gutta percha plate, and also to the armature H', Figure 10.
The points J, J", and their connections are insulated from each other by
means of the said gutta percha. Corresponding to the current points just
described opposite points are presented in the end of the adjusting screws M¹,
projecting through the stays N secured to the top of the frame O¹, which is
supported above the helices by the posts P¹, P. Secured to the stay R' is a
spring whose upper end presents a broad disc of platina to the four pole-
changing points J, J. Each spring is provided with a pair of adjusting
serews by which the stroke of the armature is regulated.
Figures 4 and 5, Plate 1, represent the key by which this apparatus is
operated, which however differs from the common key in so far that the
circuit is always closed when the lever is either up or down and is only broken
when neither point is in contact. The instruments as shown in the diagram
are in their normal position when the line is not operating; the main circuit
is closed, also that of the local battery k. The armature of the pole changer
as well as all the relay armatures on the line are resting on the back stroke.
The key levers on the line are all resting on their back points a, Figure 5 ;
see also diagram. The positive current is flowing from the main batteries b
to screw cup c to post P¹, theuce to spring Q1, thence to pole-changing point J',
thence to current-changing point K', to magnet B, thence to the vertical
magnets C', thence to screw cups d, to screw cup e of the relay, from which
they pass through the magnets C, D, to the screw cups f, thence over the
main line f¹, and back through the earth, entering te pole changer by the
ground wire at screw cup g; thence it passes to screw T, Figure 9, Plate 2,
through core D', brass bar G', up the armature II' to point J", thence to
post P", screw cup h, and to the negative pole of the battery. The eastern
magnets of all the relays on the line are thus made to at ract th ir respective

page_text: permanent magnet armatures, and their western magnets to repel them. The
local current in the meantime is passing from the battery or cup R to screw L',
thenco along spring K through the armature lever I to insulated point of
screw S, from which it passes to cup Q, thence to cupj of pole changer,
thence through the magnets A' to screw i, and thence to the local battery k.
The main current passes through the magnet B' and vertical helix C' in such
a manner that. the opposite poles of the movable core and those of the magnet
B' act together, and consequently are mutually attractive. At the same time
the local current passes through magnet A' in such a manner that its poles
are in close proximity to like poles of the movable core and act with a repulsive
force. Thus the three magnets operate to hold the armature to the east.
Suppose the operator at one station wishes to communicate with another station
he depresses his key which breaks the main circuit; the magnet B' and
movable core D become neutral, while the local current is still running.
The movable core being at once neutralized by the break of the main circuit
it is attracted by the magnet A', thus changing the poles of the main battery
instantly. By this time the operator's key has made a contact on the front
point m, Figure 5, Plate 1, thus closing the circuit, which causes all the relay
armatures on the line to move to the west, because the current is now passing
over the line in the opposite direction. On the reverse the positive current is
now passing from the main battery b, see diagram, to screw cup c as before,
thence to post P, from which it passes to spring V.through point J, thence
to armature to cross bar G', from which it passes through movable core D'
to screw T, thence to screw cup g, which is connected with the ground wire
through the earth, and back over the line f¹, entering the pole changer at
screw cup d, thence it passes through the vertical helices C' and magnets A
to screw M', thence through current changer K to point J', thence through
spring V to post P", from which it passes through screw cup h to the negative
pole of the battery. During this time the local circuit from battery k is now
broken and that of local battery is closed, and the current is now passing
from battery to screw cup i of the pole changer, from which it passes through
the inagnet B to screw cup P, thence to screw cup V of the relay, and thence
to the arch T, through which it passes to point or screw O, then down the
armature lever H to the spring K, and passes off at the ends in contact with
screw L", thence by the screw cup N to the local battery l. The three
magnets of the ole changer and those of all the relays on this line retain the
same relation to each other as before, but exert their force in an opposite
direction; thus the magnets that before attracted their respective armatures
now repel them, and vice versa. When the key lever is released the strength

page_text: I
of the spring g will throw it up, thus breaking the main circuit and allowing
the local current at the end of the line to change the poles as before.
When
the back point a of the key lever, makes contact all the relay armatures on
the line move back; hence it will be seen that as often as the key lever is
depressed the poles of the main battery will change and all the relay armatures
will move forward; and as often as the key comes up the armatures move
back, thus alternating as the key is continued to be manipulated.
The advantages of this instrument may be summed up as follows:-It is
self-adjusting from its very nature; there can be no change of current so
great or instantaneous as to impede the working of the instrument; as long
as there is force enough to move the armature in one direction it can be
moved in the other direction; it saves battery power, firstly, because it appro-
priates the power in the permanent magnet; secondly, it admits of the use of
a second electro-magnet, whereby the repelling and attracting force can bo
made to operate conjointly on the armature; thirdly, it saves power, because
two magnets, operato together with more than their aggregate of power;
further, there is no spring to overcome, and the armature being perfectly
balanced it is susceptible of the slightest influence, and by the use of a
reversible current the residual magnetism is completely overcome as an
opposing force; the main current is self-closing because it is always closed
whether the key lever is up or down, and the spring holds it up when
not in use, rendering it impossible for a careless operator to leave the circuit
open.
Having thus fully described the said Invention, as communicated to me by
my foreign correspondent, and shown how the same may be conveniently and
advantageously carried into practice, I claim,-
First. The con:municator or pole changer, relay, and key, arranged to
operate conjointly with the main and local circuits, so that the operator at any
point on the line can reverse the current over the same from, the main battery,
substantially in the manner set forth.
Second. The peculiar construction of the communicator when arranged
with the line and local circuits for the purpose of obtaining the attraction
and repulsion of the direct and reverse currents by means substantially as
specified.
Third. The communicator with an electro-magnet or vibrating core armature
so arranged that its poles lio between the poles of the electro-magnets, and
are so connected with, the line and local circuits that when both are closed
one magnet attracts the armature and the other repels it, substantially as
described.

page_text: Fourth. The arrangement of the magnet J, electro-magnets C, D, lever H,
combined and operating for the purpose and substantially in the manner set
forth.
Fifth. The magnet J, electro-magnets C, D, and lever H, operating con-
jointly with the key, Figures 4 and 5, Plate 1, substantially in the manner
and for the purpose set forth.
In witness whereof, I, the said William Robert Lake, have hereunto
set my hand and seal, this Twelfth day of October, in the year of
our Lord One thousand eight hundred and sixty-seven.
WILLIAM ROBERT LAKE. (L.S.)
Witness,
THO. N. PALMER,
Clerk to Messrs. Haseltine, Lake, & Co.,
8, Southampton Buildings,
W. C.