Improvements in and relating to Signalling Apparatus, chiefly designed for use in Engine Rooms and the like.
Year: 1892

page_text: Date of Application, 4th Nov., 1892-Accepted, 11th Mar., 1893
COMPLETE SPECIFICATION.
-
[Communicated from abroad by AMERICAN RANGE FINDER COMPANY, a
corporation organized under the laws of West Virginia, United States of
America.]
Improvements in and relating to Signalling Apparatus, chiefly
designed for use in Engine Rooms and the like.
I, HENRY HARRIS LAKE, of the firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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 :-
The invention relates to an electrical signalling system intended more particularly
for use on board ship as an engine-room telegraph.
Referring to the accompanying drawings,
Fig. 1 represents the invention diagrammatically.
Fig. 2 is a perspective view of the transmitting instrument, and
Fig. 3 is a plan view of the receiving instrument.
Similar letters of reference indicate like parts.
I will first describe the general construction of the apparatus, and the arrange-
ment of circuits as shown in Fig. 1, and afterwards refer specifically to the devices
shown in Figs. 2. and 3. At 1, Fig. 1, is represented the transmitting instrument
shown in Fig. 2. At 2, Fig. 1, is represented the receiving instrument shown in
Fig. 3. The transmitting instrument contains a conductor, a b, of wire bent nearly
into circular form. A similar conductor, cd, is arranged in the receiving
instrument 2. The ends of the conductors a b and c d are connected by circuit
wires 3 and 4. Connected in a loop wire 5, the terminals of which communicate
respectively with the middle points of the wires 3 and 4, are three galvanometers, 6, 7
and 8, the particular uses of which will be hereafter described.
Pivoted in the transmitting instrument 1 is a contact arm, 9, which, when turned
on its pivot, moves upon the wire a b. Pivoted in the receiving instrument is a
support for a contact point, 10, Fig. 1, which moves upon the wire c d. To the
pivot point of. arm. 9 and the contact point 10, are connected the terminals of a
loop, 11, which includes a battery, 12.
The circuit is therefore a Wheatstone bridge. The contact arm 9 and
contact point 10 being disposed at the middle of the length respectively of the
circular conductors a b and c d, the four arms of the bridge are as follows. First,
the semi-circle a of conductor a b and the leading wire 3 to the point of connection
of loop 5; second, the semi-circle of conductor a b and the leading wire 4 to the
point of connection of loop 5; third, the semi-circle d of conductor c d and the
leading wire 3 to the point of connection of loop 5; fourth, the semi-circle c of
It will
conductor c d and the leading wire 4 to the point of connection of loop 5.
also be apparent that when the contacts 9 and 10 occupy similar positions on the
conductors a b and c d, there will be no current in the galvanometers 6, 7, 8, and
hence no deflection of the needles. But if the arm 9, for example, be moved so
that it no longer occupies the same position on its arc a b as the contact 10 occupies
on its arc cd, then the bridge will be thrown out of balance, and the needles will be
deflected. Suppose, for illustration, the arm 9 be moved to the left over an angle
of 30 degrees, then all of the galvanometers will be proportionately deflected. If,
however, the contact 10 be also moved to the left over an angle of 30 degrees, the
equilibrium in the bridge will be restored, and the galvanometer needles will no
longer be deflected.
Consequently, if the instruments 1 and 2 be respectively located at distant stations,
it will be clear that if the operator of instrument 1 move the arm 9 over an anglo

page_text: of 30 degrees to the left, for example, the observer at the instrument 2 will be
apprised of that. fact by the deflection of the needle of the galvanometer 8. If he
then inove his contact point 10 until the galvanometer 8 shows no deflection, he will
have placed his contact point 10 in the same position with reference to the
conductor e d as the operator at instrument 1 has placed his contact arm 9 with
reference to conductor a b; and if the movement of the arm 9 of instrument 1 to a
certain point has some definite signification, then that signification will become
known to the observer at instrument 2 by reason of the extent of movement of his
contact point 10.
Galvanometer 6 is located at the transmitting station, and galvanometer 7, at the
receiving station. The three galvanometers 6, 7 and 8 being similar, the needles of
all will be deflected to the same extent simultaneously. The function of galvano-
meter 6 is to repeat to the operator at instrument 1, the indications of the galvano-
meter 8 at instrument 2. He thus becomes apprised, first, of the galvanometer
deflection caused by his movement of the arm 9, and, second, when the needle of
galvanometer 6 returns to zero, he knows that the operator at the receiving station
must have adjusted his contact point 10 correspondingly to arm 9, and hence that
the signal sent is understood.
In relay circuit, with the needle 13 and needle pivot shaft of the galvanometer 7
and with the stops 14 and 15, is a battery 16 and electric bell 17. It will be apparent
that so long as the needle 13 is not deflected, the bell 17 will not sound; but as
soon as the balance in the main circuit becomes disturbed from any cause, then the
needle 13 will move into contact with one or the other stop 14 and 15, and as a
consequence, the bell 17 will sound until the balance is re-established. In this way
an audible sound is produced at the receiving station whenever the arm 9 is moved,
and the attention of the observer at said station is thus called to the fact that a
aigual has been sent. So also, if from any cause the circuit wires become broken,
crossed, or leaky, the sounding of the bell will indicate that the circuit is out of
order, and the ringing will continue until the proper condition is restored.
66
Referring now to Figs. 2 and 3, 18 is a cylinder of sheet brass, or other suitable
material, which is supported, in practice, on a standard, part of which is shown at 19.
The cylinder 18 has circular heads, 20 and 21, of metal. In the cylinder periphery
is an opening, 22, which is closed with curved, clear glass, so that the interior of the
cylinder can be seen. It also has openings, 23 and 24, which may be closed with
either clear or simply translucent glass. On the opposite side of the cylinder, not
shown, are openings similar to 23, also closed with translucent glass. On the
openings last mentioned, and also on the openings 23, are inscribed such words as
"back" and "ahead," thus indicating the direction in which the operator is to move
the contact arm hereafter referred to. The glass which covers an elongated
opening 40 is provided with a scale-marking which should be graduated in each
direction from its middle point to indicate revolutions of the screw-shaft "ahead
and "back." On the circumferential edges of the heads 20, 21, is mounted an
envelope of insulating material, 25, and upon this envelope, which may be hard
rubber, the conductors a bare secured. It is to be understood that the instrument
shown in Fig. 2 is intended as a telegraph adapted to two engines; as, for example,
the star-board and port engine of a vessel having twin screws. Therefore, in
Fig. 2, the apparatus represented at 1 in Fig. 1 is duplicated; there being two
wires, a b, with associated parts, as hereinafter described. A single receiving
instrument is shown in Fig. 2; but it is to be understood that with such a double
instrument as is shown in Fig. 1, two such receiving instruments as shown in Fig. 2
will, of course, be employed.
"3
Returning now to Fig. 2, 9 is a contact arm pivoted at the center of the head 20,
and bent over the circumferential edge of said head and provided with a pointer, 26,
which extends over the glass scale in opening 40. On the lower side of the bent-
over portion of the arm 9, is secured a contact wiping point, 27, which bears against
the conductor a. This contact point is supported on a piece of insulating material, 28,
so that there is no electrical connection between said contact point and the arm 9;

page_text: To the
lthough said contact point is moved over the wire a by means of said arm.
ontact point 27 is secured the battery wire 11. A precisely similar arrangement
of parts exists in connection with the head 21. The terminals of each wire, a, b,
Within the cylinder 18,
re connected to the leading wires 3, 4, as indicated in Fig. 1.
and mounted on any suitable support, is the galvanometer 6. Two of these galvano-
neters are, of course, used. Supported also within the cylinder is any suitable
source of illumination; such, for example, as a small incandescent lamp provided
with a reflecting translucent shade. This lamp is connected with any suitable
source of electricity, and serves to illuminate the galvanometers within the
cylinder 18, and also to render visible, at night, the marking on the inserted glass
plates.
Referring now to Fig. 3, 28 is a disc or circular plate of brass supported on any
suitable standard. The circumference of this plate is covered with insulating
material 29, upon which insulating material is supported the wire conductor c d.
Upon the plate 28 is pivoted a plate 29, which is provided with a handle 30.
There is an opening in the plate 29, through which the outer portion of the
plate 28 can be seen. Mounted on the plate 29 is a pointer, 31, and .a contact
point 10, which point is supported on a spring 32, which bears upon the conductor cd.
The contact point 10 is supported upon a piece of insulating material, 33, and thus
has no electrical connection with the plate 29. Supported upon the plate 29 with
the pivot center of its needle 34 concentric with the pivot of said plate 29, is the
galvanometer 8. It will be evident, therefore, that when the plate 29. is turned on
its pivot by means of the handle 30, the galvanometer turns with the plate because
it is rigidly affixed thereto. Upon the plate 28 is a scale-marking corresponding
to the scale-marking on the glass plate which covers the opening 40. in the
instrument shown in Fig. 2. This marking may be numbered to indicate revolu-
tions in the same way as said glass plate is marked; and it may also have such
inscriptions as "full speed,"
"half speed," "slow" and "stop," as shown. Also
"back" and "ahead"
on the plate 28 may be additional inscriptions, such as
conformably to the inscriptions on the instrument shown in Fig. 2.
The operation of the apparatus, in practice, is as follows:-
The instrument shown in Fig. 2, as already stated, is located on the deck or
bridge of the vessel, and is manipulated by means of a handle, such as 34, attached
to the arm 9. Let it be assumed that it is desired to send a signal to back at a
speed of a certain number of revolutions. The operator, grasping the handle 34,
draws it toward him, or in the direction indicated by the plate marked "back"
the instrument. Noting the pointer 26, he adjusts that pointer over the scale-
marking on the glass plate covering the opening 40, which corresponds to the
desired number of revolutions of the screw. In doing so, he necessarily moves the
contact point 27 over the conductor a b for a certain distance, and thus throws
the circuit out of equilibrium.
"
on
Let it be assumed that the effect of his so doing is to cause the needle 34 to
move to the position indicated in Fig. 3. From the fact that the needle moves
toward the inscription "back" on the instrument in the engine-room, the observer
there stationed will know that he is to reverse his engine, and he also will know in
which direction he is to move the handle 30 in order to bring the circuit back to
equilibrium. The observer in the engine-room, grasping the handle 30, then moves
it in the indicated direction, or to the left; and at the same time, he moves,
necessarily, the pointer 31 over the scale on plate 28. The effect of his moving the
handle 30 in the direction indicated, is, of course, to move the contact point 10;over
the wire cd; and if the galvanometer 8 did not move also, the result would
simply be that the galvanometer needle would move back to zero; the needle
moving in one direction as fast as the pointer 31 moved in the opposite direction.
But because the galvanometer also moves with the contact point 10, the resultant
so that the observer has
5. of the two motions is to keep the needle stationary:
simply to note the direction of the needle 34 when it is deflected, and to bring

page_text: +
the pointer 31 in line with that needle. When he has done this, he will have
adjusted the circuit to compensate for the disturbance caused at the sending station
by moving the handle 34; and as a consequence, the galvanometer 6 at the sending
station will return to zero.
It will be seen, therefore, that the deflection of the galvanometer 8 not merely
acquaints the observer in the engine-room with the direction in which he is to move
the handle 30 and also with the extent of movement necessary of that handle, but
it serves as a visible mark for him to adjust that handle by. This is a very
important and essential point which differentiates my apparatus from another
form of telegraph with which I am acquainted. It makes it impossible for the
receiving operator to set his contact point wrong, and thus prevents errors which
might occur in times of great haste and emergency.
The following points are also to be noted. The arrangement of the bridge is
to be such (and this is illustrated in Fig. 1) that a movement of the arm 9 to the
left is to cause a deflection of the needle of the galvanometer 8 to the left, and a
movement of the arm 9 to the right is to cause a deflection of said galvanometer
needle to the right. The wires a band c may be conveniently made of nickel
German silver, with their ends secured in metal plates or clamps, as shown at 36,
Fig. 2. It is better to imbed the wires c d and a in shallow grooves in the bands
of insulating material, which will serve to hold them in place.
Between the leading wires 3 and 4 and the transmitting instrument 1, and also
between said leading wires and the transmitting instrument 2, are disposed short
coils of nickel German silver wire, 37. Three of these coils may have a resistance
of two ohms; the other of 1.9 ohms. The advantage of this arrangement is that
when the contacts 10 and 9 are in the same position on their respective conductors,
the galvanometer needles are considerably deflected from the position of rest,
although they occupy the middle parts of their respective scales. This does not
alter the operation of the instrument, as before explained, but the important object
attained is, that if any accident whatever befall the apparatus, the bell 17 will at
once give the alarm; because, no matter what happened, (if the "bridge" battery
gave out, if a wire be cut, if any contact became imperfect, or if any connection be
broken in the "bridge"), the needles in the galvanometers will at once quit their
normal positions, and this, in itself, is an indication that something is wrong.
addition, local circuit will be closed at the galvanometer 7, and the bell, as already
stated, will ring an alarm until the injury be repaired. This property of self-
detection and automatic announcement is of great value, and does not exist in any
other form of similar apparatus with which I am familiar. In the ordinary engine-
room telegraph, an injury may happen, and remain totally unknown until an attempt
is made to signal; and if this should happen in time of great emergency, the
result might be serious disaster to the ship.
In
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed as communicated to me
by my foreign correspondents I declare that what I claim is
1. The combination of a source of electricity, two similar bodies of conducting
inaterial located at distant stations, pivoted supports provided at their extremities
with contact points moving upon said conductors and combined with one of said
supports so as to be moved therewith, an electrical indicating or measuring instru-
ment having a pivoted index or pointer, the pivot center of said index coinciding
with the pivot center of said support; the said elements being connected in Wheat-
stone bridge circuit, substantially as described.
2. The combination of a source of electricity, two similar bodies of conducting
material, a b, c d, located at distant stations, pivoted supports provided at their
extremities with contact points moving upon said conductors, unequal resistances at
the extremities of a b and c d and an electrical measuring instrument having a
needle or pointer oscillating between fixed stops, and an electric bell or alarm in

page_text: relay circuit with said stops; the said conductors, supports, measuring instrument,
resistances and source of electricity being connected in Wheatstone bridge circuit, -
substantially as described.
3. In an electrical signalling system the combination of a source of electricity,
two bodies of conducting material, two contact points moving on said conductors
and an electrical indicating or measuring instrument; the said elements being con-
nected in a Wheatstone bridge circuit so constructed or arranged that, when the
two contact arms press on the conductors at points similarly marked at the two
stations, the bridge is not in equilibrium, substantially as described.
4. The construction and arrangement of the transmitting instrument herein-
before described.
5. The construction and arrangement of the receiving instrument hereinbefore
described.
31° hd of November 1892
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.