An Improved Electrical Repeater and Commutator to Indicate the Normal Position and the Movements of Railway or other Signals, Slots, and the like.
Year: 1889

page_text: Date of Application, 3rd June, 1889
Complete Specification Left, 1st Mar., 1890-Accepted, 26th Apr.,.
1890
PROVISIONAL SPECIFICATION.
An Improved Electrical Repeater and Commutator to Indicate the
Normal Position and the Movements of Railway or other Signals,
Slots, and the like.
I, DAVID WELLS of 14 Brunton Place, in the City of Edinburgh, Telegraph
Engineer, do hereby declare the nature of my said invention to be as follows:-
The electrical repeater consists of a bobbin of silk-covered wire fixed between two
permanent magnets. An axle is placed free to move inside the bobbin of silk-covered
wire, and is influenced by currents passing through the wire. Upon the end of the
said axle, and moving on the outside of the dial is fixed a semaphore signal arm, or
indicator, and immediately behind this on the inside of the dial is a backweight to
bring the semaphore arm to the normal position when no current is passing. There
is also an adjustable supplementary backweight or check to ensure
indications.
accurate
The commutator consists of the usual contact making arrangement, but with the
addition of a resistance coil, or coils, placed in circuit between one or more of the
contact plates or wires in the commutator and the "earth "connection.
The unique feature of my invention is the obtaining of indications on the electrical
repeater of three or more distinct and different movements of the signal arms, rods,
slots, and the like, using a single line wire, and with the battery placed in the
signalman's box, by bringing a resistance coil, or coils into circuit between the
coinmutator and the "earth" connection, and providing an adjustable supplementary
back weight, or check in the electrical repeater to ensure accurate indications.
Deted this 7th inre of Mar 1000
DAV. WELLS.
COMPLETE SPECIFICATION.
An Improved Electrical Repeater and Commutator to Indicate the
Normal Position and the Movements of Railway or other Signals,
Slots, and the like.
.
I, DAVID WELLS of 14 Brunton Place in the City of Edinburgh, Telegraph
Engineer, 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 electrical repeater consists of a bobbin of silk covered wire, fixed between two
permanent magnets, with an axle placed free to move inside the bobbin of silk
covered wire, and which is influenced by currents passing through the wire. Upon
the end of the said axle and moving on the outside of the dial is fixed a semaphore
signal arm, or indicator and immediately behind this, on the inside of the dial, is fixed
a backweight, which keeps the semaphore arm in the normal position when no current
is passing
There is also, on the inside or back of the dial, an adjustable supplementary back-
weight, or check, to ensure accurate indications.
The commutator consists of a box in which is inserted a glass tube containing a
small quantity of mercury (M). Into this tube two wires are carried at (N) and two
wires at (N). The box also contains a resistance coil (R) and the necessary connecting
wires.
When the service signal indicates "danger" the commutator is in the position
shewn in Fig. 5 and the mercury (M) being clear of the wires the electrical circuit is
broken therefore no current passes and the arm (C) of the repeater is in the position
shewn in Fig. 2.

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When the service signal is partly or insufficiently drawn, indicating neither
danger nor "clear" the mercury (M) in the glass tube flows to the two wires
at (N) placing them in contact and completing a circuit from the battery through
repeater, line wire contact point-(N) in commutator resistance coil (R) and
This causes the arm (C) of the repeater to fall to the position shewn in Fig. 3, the
back weight (G) being stopped by the check (H) on reaching this point.
earth."
When the service signal falls sufficiently to indicate "line clear the mercury (M)
in the glass tube flows to the two wires at (N) placing them in contact and completing
a circuit from battery, through repeater, line wire, contact point (N¹) in commutator,
and "earth." The resistance coil (R) being now thrown out of circuit, the current is
proportionately strengthened and the check (H) in the repeater is raised by the
back weight (G) bringing the arm down to the position shewn in Fig. 4.
In order that my said invention may be fully understood and readily carried into
effect I have herewith appended drawings which I will proceed to describe.
DESCRIPTION OF DRAWINGS.
Figs. 1 & 2 are sectional plans of the repeater, Fig. 2 shewing the position of the
arm C when the commutator is in the position shewn in Fig. 5.
.
Fig. 3 is a section of the repeater shewing the position of the arm C when the
commutator is in the position shewn in Fig. 6.
Fig. 4 is a section of the repeater shewing the position of the arın C when the
commutator is in the position shewn in Fig. 7.
Fig. 5 is a section of the commutator, lid removed, and shewing its position on the
service signal when the latter indicates "danger."
Fig. 6 shews the position of the commutator when the service signal is partly or
insufficiently clear.
Fig. 7 shews the position of the commutator when the service signal indicates" line
clear."
In these drawings the same reference letters and numerals are used to mark the
same or like parts wherever they are repeated.
A. is the coil or bobbin of insulated wire.
B & B are the permanent magnets.
C. is the miniature signal arm.
D. is the axle.
E. is the pillar support keeping the dial rigid.
F. is the coil support.
G. is the backweight fixed to the axle.
H. is the supplementary back weight or check.
L. is a glass tube containing a small quantity of mercury M and into which glass
tube are carried two wires at N and two at N.
R is the resistance coil.
S & S are the wires connected to line wire.
T is the wire connected to earth.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
..I claim is :-
1. The obtaining of indications on the electrical repeater of three or more distinct
and different movements of the signal arms, rods, slots, and the like; using a single
line wire, and with the battery placed in the signalman's box; by bringing a resistance
coil or coils into circuit between the commutator and the "earth" connection, and
providing an adjustable supplementary backweight or check in the electrical repeater
to ensure accurate indications.
Dated this 20th day of February 1890