A NEW OR IMPROVED ELECTRIC DISC AND BELL INSTRUMENT FOR RAILWAY SIGNALING, APPLICABLE ALSO IN PART TO OTHER PURPOSES
Year: 1876

page_text: LETTERS PATENT to William Harling, of Marylebone, in the County of
Middlesex, Telegraphic Instrument Maker, for the Invention of "A NEW OR
IMPROVED ELECTRIC DISC AND BELL INSTRUMENT FOR RAILWAY SIGNALING,
APPLICABLE ALSO IN PART TO OTHER PURPOSES."
Sealed the 4th April 1876, and dated the 14th January 1876.
PROVISIONAL SPECIFICATION left by the said William Harling at the Office
of the Commissioners of Patents on the 14th January 1876.
WILLIAM HARLING, of Marylebone, in the County of Middlesex, Telegraphic
Instrument Maker. "A NEW OR IMPROVED ELECTRIC DISC AND BELL INSTRUMENT
FOR RAILWAY SIGNALING, APPLICABLE ALSO IN PART TO OTHER PURPOSES."
This Invention relates to improvements in electric disc and (single stroke) bell
instruments for railway signaling, applicable also in part to other purposes.
According to my Invention the working of the disc, bell, and locking is accom-
plished with one coil or electro-magnet formed of a series of poles, each pair
tuned inwards towards one another and all surrounding the core or generator.
For this particular instrument the poles are arranged one pair on each side of
the core and one pair on the top, the instrument being constructed so that when
the electric current is on, one side pair of poles will attract the hammer and so
strike the bell, and the other side pair attract the locking keep of the disc needle,
releasing same, and allowing it to be worked either by a positive or negative
current. The disc needle is made by preference of soft iron, and in form the
segment of a cylinder, insulated from its axis, which axis works at its opposite
points in bearings, at one end being the disc and at the other the locking pin.
The needle is placed between the pair of poles at the top of the electro-magnet,
and is influenced by a compound permanent magnet placed above it. The instru-
ment is worked by the ordinary pair of tappers. The needle remains locked
except when the current is on, thus obviating the necessity for a continuous
current, and ensuring the locking of each disc signal given.
Electro-magnets formed as above may be used for a variety of purposes. A
double disc instrument may be formed with two of such coils.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Harling in the Great Seal Patent Office on the 8th July
1876.
WILLIAM HARLING, of Marylebone, in the County of Middlesex, Telegraphic
Instrument Maker. "A NEW OR IMPROVED ELECTRIC DISC AND BELL INSTRUMENT
FOR RAILWAY SIGNALLING, APPLICABLE ALSO IN PART TO OTHER PURPOSES."
This Invention relates to a new or improved electric disc and bell instrument for
railway signalling, applicable also in part to other purposes.
And in order that iny Invention may be clearly understood and readily carried
into effect, I will proceed to describe the same with the aid of the accompanying
Drawings, reference being had to the letters and Figures marked thereon. The
same letter of reference when occurring in the different, Figures relating to the same
instrument indicates like or corresponding parts unless otherwise stated.
According to my Invention the working of the disc or lever, the striking of the
bell, and the locking of the signal given are all accomplished with one coil or
electro-magnet of peculiar construction. It is formed of a series of pairs of poles,
each pair turning inwards towards one another and all surrounding the core or
generator, and arranged according to requirements. For this particular instrument
the poles are arranged one pair on each side of the core and one pair on the top, as
shewn at A, Figures 1 and 2, Figure 1 being a front elevation, and Figure 2, a plan.
The three pairs of poles are marked respectively e¹, a, a, a, and a³, a³. The bell
keep B to which the bell hammer is attached works easily on a screw centre at
each end passing through a standard (in the ordinary manner), so that when the
current is on the keep will be attracted by the side poles a¹, a', and so strike the
bell. The locking keep C of the disk needle D is hung in like manner, so that it
may (at the same time) be attracted by the side poles a, a, and so release the
locking pin of the disc needle D, and allow the needle and disc E to be raised or
lowered according to the current (positive or negative) used, and which is.
accomplished by the needle being attracted to the positive pole of the electro-
magnet A. The disc needle D is made by preference of soft iron and in form the
segment of a cylinder. It is insulated from its axis & which works at its extremities
in bearings and carries the discs E' and the locking pin c. The needle D is placed
with the break in its cylindrical form between the extremities of the top pair of
poles a, a, of the electro-magnet A, the needle being almost in contact therewith.
The needle is also influenced or kept polarised by a permanent magnet I by
preference compound. Or instead of using a soft iron needle and permanent
magnet the needle may be of steel polarised, and the permanent magnet be
dispensed with. The keeps B and C are held off the poles when the current is
not on by light springs, as shewn at b and c (see Figure 2); b being a blade
spring, and c a spiral spring.
The instrument is worked by a pair of ordinary tappers (H and I), shown in
elevation at Figure 1, and in plan (taken at the line 1, 2, Figure 1), at Figure 3.
On each tapper are fastened two insulated pins (marked respectively h, h, and i, i¹).
The tappers are centred on body blocks (J) and under the back end of each is a
rest, and under the front end of each a tapper stud (marked K and L), the tappers
being kept off these studs (except when pressed down to make contact) by blade or
other suitable springs. Between the front part of the tappers is placed a stud (M)
to the top of which is attached by its base a fork-shaped blade spring (N), having
under the extremity of each end a stud (O and P). These studs are brought in
contact with the springs only when the latter is depressed by means of the insulated
pins and Between the back part of the tappers is placed another stud Q to
the top of which is attached a blade spring (R), having under its opposite extremity
another stud (S) always in contact therewith, except when the spring is mised by
the insulated pins, . The line wire is attached to the terminal T (Figure 1)
whence it passes to the body blocks J (which are connected by a wire), thence by
stud Q, spring R, and stud S to terminal U, to which is attached the coil wire of

page_text: the electro-magnet A, the other end being attached to earth terminal V. This
terminal is also connected with stud M; stud P is connected with stud K, and stud
O with stud L. The terminals W and X are connected each with one pole of the
battery and with one of studs K and L. In receiving a message through the
instrument (and the current taking the direction described in passing through
the coil of the electro-magnet) the magnet attracts both, keeps B and C striking
the bell and releasing the disc needle pin e, whilst at the same time the right-hand
one of the top poles attracts the disc needle over to it, and either raises or lowers
the disc or arms according to the arrangement. A current through the instrument in
the opposite direction attracts the needle in that direction. Tho disc or arm by its
position may thus be made to indicate line "clear" or "blocked." In sending a
message from the instrument one of the tappers H or I (according to whether tho
positive or negative current is to be used) is depressed. Supposing it to be the -
tapper H contact is made with the stud K, thus enabling the current from one pole
of the battery to pass by means of the battery line through terminal W, stud K,
tapper H, and body block J to the line terminal T, and thence to its destination
and through the receiving instrument to earth line, returning through earth
terminal V, stud M, spring N, stud O, and front tapper stud L to terminal X, and
thence to the other pole of the battery, thus completing the circuit. A current in
the reverse direction could be sent in like manner by depressing tapper I instead of
tapper H.
The above completes the description of the single stroke bell, disc, and locking
instrument, and in constructing such an instrument the electro-magnets Y and Z
and their appendages, illustrated at Figure 1, and the switch A¹ illustrated in
Figures 1 and 3 must be omitted; Figures 1 to 3 taken in full illustrate an
instrument by which the up and down lines of a railway may be worked by a
single line wire and earth current or return wire. To those parts already described
are added the two electro-magnets Y and Z. These have poles only on top and
one side, no hammer or hammer keep being required. The top poles are used to
actuate the disc needle and disc, and the side poles to lock and unlock the signal,
in the same manner as already described with respect to electro-magnet A. In
this case there is also provided a switch A¹ and studs B, C, D, and E. The right.
hand wires from the three electro-magnets are connected with terminal U, whilst
the three left hand wires are connected, that from A with stud C¹, that from Y
with D, and that from Z with E¹, also the stud B¹ is connected by a wire with M
and with C by means of the blade spring F¹.
"
"
In using this instrument the disc of electro-magnet A is made to indicate by its
position whether the message to be received relates to the up or down line,
instead of, as described, with the other instrument indicating blocked or
"clear." The motion of the said disc on the receiving instrument is arranged to
indicate "up line," when the right hand tapper on the sending instrument has been
depressed, and "down line" when the left hand tapper has been depressed. When
thus the line has been indicated (say the up line) the receiver of the message presses
the handle of switch A¹ to the right; this raises spring F¹ from C₁, destroying
contact therewith, and breaking the circuit with electro-magnet A, but leaving the
signal locked. At the same moment the cross bar of switch A' comes in contact
with stud D', thus bringing electro-magnet Y (the up line magnet) in circuit when
the disc is immediately set to "blocked" or "clear," according to whether a
positive or negative current is sent through from the sending instrument, that is,
whether the right or left hand tapper has been depressed. The handle of the
switch being then released resumes its upright position, bringing the bell and its
coil again in circuit and leaving the line signal locked. In reference to the down
line the left hand tapper is depressed to send the message, whilst to receive tho
message the handle of the switch is pressed over to the left hand, the cross bar
breaking contact with stud and coming in contact with stud E¹ brings
electro-magnet Z (the down line magnet) in circuit, when the disc is set as before
described.

page_text: Figures 4 and 5 illustrate my improved electro-magnet applied to a semaphore
instrument; Figure 4 being a back elevation, and Figure 5 a front elevation.
Two of my electro-magnets, A and B, are placed side by side with sufficient space
between them to allow of a double armature or keep C of the forin shewn, from
which it will be seen that as one side of it (forming the keep for one magnet) is
attracted to its magnet the other side (forming the keep for the other magnet) is
drawn therefrom. The keep is hung on a bearing D at each end so as to work
freely. Each electro-magnet is provided with two pairs of poles, the side poles of
each (a and b) being placed between the two coils towards and to act on the
double keep C, the other poles (a and b) being placed at a convenient angle as
shewn to attract the locking keeps E and F. The arms of these keeps are centred
cach on a horizontal axis, supported in front and back bearings D, and are
extended inwards beyond same to a double lock piece G, attached to the top part
of the double keep C, and receiving motion therefrom. The said keeps E. and F
are held off the poles of the magnets when the current is not on by springs H and
the lock picce G; I is an ordinary plunger, to complete the circuit for sending
a messago; and J, K, L, and M, are terminals; N is a small counterbalanced
semaphore arm attached rigidly to the front extremity of the axle of double keep C,
and D is the front bearing for the said axle; O is the face plate of the machine,
and P the framework. Ono end wire of coil B is connected with terminal L, and
the other end with body of plunger I. Spring at back of plunger is connected
with terminal M. One end of coil A is connected with terminal K, and the other
with terminal J which is also the earth terminal, M and J are also battery
terminals. In sending a message to the next signalling station in the rear the
plunger is depressed making contact with spring at back.
The current then passes
from battery by terminal M spring at back of plunger, and body of plunger to one
end of coil of magnet B, and in passing through same attracts keep F, raising the
rear end of its arin and unlocking C, and enabling it to be attracted over to the
magnet B and raising the semaphore arm to a horizontal position or " blocked."
The motion of C is imparted to the lock pieco C, which is turned towards coil A
and under the bent extremity of the arm of keep E, until it clears same, when the
spring attached thereto draws it over and locks the signal. The current then from
coil B passes by terminal L to line, and thence to receiving instrument at
terminal K and to one end of coil A, passing through which it attracts keep E
(as shown in the Drawing) raising its rear arm and releasing lock piece G when
keep C is immediately attracted to coil A, as shewn, and the semaphore dropped to
"clear." The current thence passes to terminal J, and by earth to the sending
instrument, completing the circuit. Thus the message sent blocks the sending
station and clears the receiving.
Figure 6, which is an end clovation, shows my improved electro-magnet applied
to work the line semaphore arms simultaneously with the instrument above
described, to which it may be attached and worked thereby. A is the coil of the
electro-magnet, and a¹ and a² the poles; B is a locking keep, the arm of which is
centred on a horizontal axle, and extends beyond to the locking piece E, the
extremity being turned down to catch on same. When the current (positive or
negative) is on the keep, B is attracted to poles a³, thus raising the rear end of its
arm and unlocking keep C, which is then attracted to poles al and lowers the
semaphore arm D which is attached to the same axis as keep C. When the
current is broken the counterbalanco weight of the semaphore raises it again to
the horizontal position, the locking piece E slipping under the turned end of the
arm b' of locking keep B, which latter then falls by its own weight into the
position shewn and locks the semaphore arm D. The lines are connected to terminals
in the ordinary manner.
Figure 7 illustrates my improved coil applied to a single stroke bell. A is the
coil and a¹ the poles; B is an adjustable spring to hold the hammer keep off the
poles when the current is not on; C is one of the end standards to which the keep
is hung, the keep being shewn behind same by dotted lines; D is the hammer and

page_text: E the bell is an ordinary tapper for working the instrument. The lines are led
to terminals in the ordinary manner. When the current (positive or negative) is
on, the keep is attracted to the poles of the magnet and the bell is struck. As
soon as the current is broken the spring B releases the keep from the poles and
retains it in readiness for the next signal.
Figure 8 illustrates my improved electro-magnet applied to an instrument for
continual ringing whilst the current is on until stopped by the receiver, there being
also a visible signal in the form of a flag or arm moved to shew that the call has
been made. A is the coil, and a', a¹, and a, a, the two pairs of poles; B is the
hammer keep which is held off the poles when the, current is not on by means of
the springs C, to which it is attached; D is a spring (attached to a standard)
through which the current passes to or from the electro-magnet; E is the flag
locking keep held off the poles, ², when the current is not on by spiral spring F.
On the back of keep E is a small lock piece c, on which catches a lever G attached
to the flag spindle, and by which the flag is maintained in a raised position when
the current is not on; EL is the flag; I and J are the battery terminals; K and L
are the line and return or earth terminals. In receiving a message the lines from
K and L are connected at the sending station. The current by one of them
(say L) passes by connections to stud M. (on which is centred the flag and levers G
and thence to terminal I and the battery. The current being continued by the
other line wire to terminal K passes thence to one end of the coil through the coil
stud N, spring C, keep B, and spring D, to terminal J, and the battery thus
completing the circuit. When the two line wires are connected at the sending
station, and the current thereby caused to flow as described, the electro-magnet
attracts the two keeps B and E, the hammer striking the bell and the flag
dropping. When the flag drops the curved lever drops on to spring O supported
on stud P, which is connected with terminal K, thus completing the circuit
independently of the two line wires. The bell is kept ringing through the break
and make between B and D until stopped by the receiver. This is effected by
depressing the tapper Q, the back end of which comes in contact with lever h
raising same together with the flag and lock lever G, at the same time breaking
the connection between h and O when the keep B and E fly away from the poles
of the magnet, the keep E locking lever G.
Figure 9 illustrates my improved electro-magnet applied to turning a disc step
by step at each stroke of the tapper of the sending instrument. These successive
steps will indicate name or number, according to arrangement. A is the electro-
magnet having two pairs of poles (one pair on each side) a¹ and a Opposite each
pair is hung a keep on centres, as already described, and to the top part of each
keep is attached a lever (B and C). The keeps are held off the poles when the
current is not on by springs 1). Above the coil is placed the disc E turning on an
axle supported in suitable bearings, and having on its face a number of pins c.
The levers B and C are cach provided with a pallet, which enters between two
contiguous teeth. When the current is put on, the keeps are attracted, giving
motion at the same time to the levers B and C, lever B being caused through its
pallet to draw on one of the teeth and so move the disc partially round, the lever
being at the time withdrawn to allow of this movement.
On the current being
broken the keeps are drawn back by the springs D, the pallet on lever C thus being
forced in the space between two teeth then opposite, and by its form com-
pletes the travel of the disc for the space between the centres of the two
contiguous teeth, the pallet on lever B also entering a space ready for the next
current.
Figures 10 and 11 illustrate respectively in end and side elevation my improved
electro-magnet applied to the working of an escapement driven by a train of
wheels. A is the electro-magnet, having one pair of poles at the side. Opposito
these poles is hung a keep Bon centres in the manner already described, and to
this keep B is fixed rigidly and in an upright position an arm C. To the top of
this arm is fixed a small projection cl, making at the top two points in a different

page_text: This
vertical plane. When the current is on, the keep is attracted to the poles, and the
point c' at the top of arm C arrests a tooth of the escapement wheel D. When
the current is broken the keep is drawn away by the spring E and the point c¹ out
of the plane of the wheel which immediately escapes round until the next tooth
meets the point of C which has been brought into the plane of the wheel.
position is shown in the Drawings. The action is continued alternately. The
inake and break of contact to complete and interrupt the current may be regulated
by a clock pendulum, as in the case of a master clock to regulate a number of
other clocks.
Figure 12 illustrates in front elevation my improved electro-magnet applied to a
reading and block dial. The front dial is removed in order to shew the parts
behind. A is the electro-magnet, having two pairs of poles, one pair in front and
one pair at top; B is the bracket on which it is supported; C is a keep hung in
front of the front pair of poles on screw centres passed through brackets D; E is a
magnetic needle for giving motion to the front or reading needle G. The needle E
is similar to that described in reference to Figure 1, and locks the signal in a
similar manner. It is influenced by the permanent magnet H, and is actuated by
the poles a, a, between which it is placed. The direction of the movement of
the needle G is thus regulated by the direction in which the current is sent through
the coil. Without the keep C and locking arrangement the instrument may be
used as a reading dial.
My improved electro-magnet is also applicable generally to electrical instruments.
Amongst numerous others may be mentioned locking bells for omnibuses, tram
cars, railway and road carriages, and for other purposes, domestic drop disc
instruments, drop disc and whistle instruments, relays, and motors for sewing
machines and other purposes.
What I claim as iny Invention, and desire to secure by the herein-before in part
recited Letters Patent is,-
First. An electro-magnet having one pair or several pairs of poles, each pair
turning inwards towards one another over the core or generator, as described and
illustrated.
Second. The electric disc and bell instrument illustrated and described in
reference to Figures 1, 2, and 3, whether constructed for working a single or
double line of railway.
Third. The methods described and illustrated of applying my improved electro-
magnet to the various instruments illustrated in Figures 4 to 12 of the accom-
panying Drawings.
In witness whereof, I, the said William Harling, have hereunto set my hand
and seal this Eighth day of July, in the year of our Lord One thousand
eight hundred and seventy-six..
Witness,
E. W. SEARLE,
Draughtsman to J. W. Gray, C.E.,
16, Southampton Bdgs., W.C.
WILLIAM HARLING. (L.S.)