Improvements in or relating to Railway and other Signalling.
Year: 1898

page_text: Date of Application, 30th Aug.,
1898
00th
سلسل
4800
PROVISIONAL SPECIFICATION.
Improvements in or relating to Railway and other Signalling.
We, WILFRID SWANWICK BOULT, of "Sudbury," Beechcroft Road, Upper Toot-
ing, in the County of Surrey, Civil Engineer, and CEDRIC RANDAL BOULT, of H 11
Exchange Buildings, Liverpool, in the County of Lancaster, Merchant, do hereby
declare the nature of this invention to be as follows:-
This invention relates to improvements in signalling and has special reference
to the magnetic system of signalling for which Letters Patent numbered 17041
of 1893, 11773 of 1894, 2282 of 1895, 8724 of 1895, and 20735 of 1895 granted
to us, and further described in the Specification of our Application for Letters
Patent No. 29257 of 1897.
One object of this invention is to effect an improved construction of and sup-
port or attachment for the road magnets. With a view to occupying but little
width of the roadway at or near rail level, and at the same time to afford great
protection to the magnets, we may according to this invention bury these (in
a more or less nearly vertical position) in a solid piece of timber placed edgeways
on the sleepers. The lower ends of the magnets may be connected either by other
magnets or by iron bars or plates with other vertical magnets or bars or with the
chairs (and so with the railway metal, as suggested in our Patent No. 17041 of
1893) for the purpose of reducing "air gap and guiding the magnetic flux to
the desired pole-plates of the armature. Since magnets may be placed in con-
nection with each rail both inside and outside there are four positions on the
road from which an armature relay can be operated while the width of roadway
occupied by the magnet supports is extremely small.
23
«
on" signals (which
In view of the immense importance of the "danger" or
we prefer to give by permanent magnets) and in view of the fact as hereinafter
explained that all necessary signals can be controlled by three armatures, we pro-
pose to utilize the fourth position on the road for duplicate sets of permanent
magnets the engine by preference carrying duplicate armatures in correspond-
ence. If the two outside or the two inside positions (on the engine or on the
road or both) are occupied by apparatus for giving the same signals in duplicate,
the corresponding circuits on the engine will be permanently right, whichever
end the engine runs first; consequently they never need be interfered with, and
only the "off" connections require to be switched over for reverse running. If
two on armatures and duplicate magnets are used, one needle in each armature
will suffice and its movement will be stronger than if there were two: the con-
struction also will be somewhat simplified. Another object of this invention is
to provide an improvement in the general arrangement or scheme of signalling
whereby with only two armatures we are able to operate the following signals
or fault movements, and
riz: two semaphores or their equivalents, two, "spot'
three route indications. To do this we so connect the indicator movements that of
the four signalling circuits (after parallel needle circuits have passed the "spot"
coils, and united at least magnetically) two give the home and distant
"
"
65
on
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page_text: signals respectively and each of the other two actuates a special route number
and a common general "line-clear" signal (for instance, throws down both
semaphores at once). With suitably arranged electro-magnets on the road,
either or both of these numbers can be given. With only one electro-magnet
at each position either of two routes can be given. With another armature for
route numbers and two electro-magnets to each armature eleven different routes
may be given.
66
66
6.
"
66
وو
To call attention to the movements of the signal indicator we prefer to use
two different toned bells (controlled by the distant and home semaphore tongues
respectively after the manner of an ordinary relay) arranged to ring while tho
semaphores are in the " on position and to stop ringing when the signals are
off." To enable the bells to be stopped by hand if so desired without inter-
ference with the signal indicator we may insert in the bell circuit a second relay
movement (preferably in an independent case) hereinafter referred to as the
push relay" to be closed by the signal current and capable of being opened
by hand; and in order that it may be impossible for the push relay to prevent
the ringing of the bell by an on signal we prefer that the opening of the
relay shall be effected by a magnetic pull which will be neutralised by the "on"
signal current. The apparatus we prefer to use is in form a modification of the
replacer push" described in the Specification of our above-named Application
No. 29257 of 1897. For our present purpose the apparatus comprises a polarized
pivotted relay tongue the free end of which plays between an iron core surrounded
by one or more coils traversed by the signal currents and a hinged or flexible
iron bar or equivalent preferably connected by an iron yoke with the polarising
magnet and the iron core. In its normal position the tongue is lying against an
insulated contact in the end of the core (or equivalent device) so as to close the
bell circuit through the relay, the tongue being attracted to, but not quite touch-
ing, the iron of the core. To break the bell circuit the hinged iron bar (which
may be normally held back by a spring or otherwise) is pushed forward till it
touches the tongue (or more nearly so than the core does) which is then held or
attracted to the said bar more strongly than to the core. The bar being then
moved away brings the tongue with it and the bell circuit is broken.
time during or after this movement of the bar by which the tongue is detached
from the insulated contact, a single current in the coil will snatch away the
tongue from the bar and throw it against the said contact thus again closing the
bell circuit.
At any
This device may be serviceable in signalling apparatus for a variety of pur-
poses where the signals are received by apparatus that has to be readjusted and
where it is desirable that the reception of a further signal during the readjusting
operation shall not be interfered with by that operation. For example it may be
employed in the signalling circuit of winding engines in mines and similar places
so that the engine attendant may stop his bell and yet be open to receive signal
whilst so doing.
Another improvement is in the construction of polarized relays such as we
use in the engine armatures for closing the signal circuits.
According to our present invention we are able to place one or more needles
in one "gap" and to both polarize and control the same by means of one magnet.
By preference we pivot the needle at its centre and polarize and control both
ends, and we will describe the construction as so applied. We will consider one
needle only, placed in a gap in the iron bridge piece of an armature of the kind
described in our above mentioned Letters Patent No. 11773 of 1894. In order
that this needle may be normally held in the middle of its swing (or
trolled ") without a special controlling magnet, spring etc.. we make the sides of
the gap that is the width of the polar ends of the separated portions of the
bridge-piece, approximately equal to the length of the needle: we also by pre-
ference provide each of these polar ends with horns at its sides projecting in a
direction more or less nearly parallel to the needle, the tips of the horns lying
con-

page_text: close to the ends of the needle. A permanent magnet is placed so that one end
of the needle and the two adjacent horns, one on each polar end, are magnetised
with north polarity and the other end of the needle and the horns adjacent thereto
with south polarity. The polar ends and needle thus form a system of three
similarly polarised magnets of which the central one is pivotted while the two
sides ones are rigidly held, the former will therefore, as is well known, take up a
position of stable equilibrium, about equidistant from the two latter. Cross
magnetism due to road magnets will deflect the needle as described in our previous
Letters Patent hereinafter referred to.
It is evident, that instead of using a separate permanent magnet to polarize
the needles and polar ends these may themselves be "permanently" magnetized.
The special feature of this part of our present invention is the application of what
may be described as a "repulsion control" as distinguished from the attraction
control as previously employed.
Advantages accruing to this repulsion control are that the magnet adjustment
need not be nearly so fine as in an attraction control, the practicable swing of
the needle is greatly increased and the form of poles of the said magnet of minor
importance.
This method of control is broadly applicable to polarized relays for all signalling
purposes in general and particularly to those in which three significant positions
are desired.
For automatic block working on our magnetic system we may use at each block
station a "two point" switch-preferably actuated by a polarized movement
and two armatures so connected up that as the magnet carried by the train passes
say the first road armature of a pair the switch at the station is thrown so as to
cut out the line-clear electro-magnets which the train has just passed (thus
blocking the line), and to close a gap in a circuit connected to the preceding
switch so that when the second armature closes a second gap the circuit is com-
pleted and the electro-magnets of the block section in rear of the preceding switch
are again energized so as to pass on a succeeding train. This device makes it
impossible to take off the block on one section until the section in advance has
been blocked.
Instead of breaking the circuit of the electro-magnets, we may, if preferred,
render them inoperative by short circuiting them by means of the automatically
operated switches.
Dated this 30th day of August 1898
BOULT & WADE,
Agents for the Applicants.
Improvements in or relating to Railway and other Signalling.
We, WILFRID SWANWICK BOULT, of "Sudbury," Beechcroft Road, Upper Toot-
ing, in the County of Surrey, Civil Engineer, and CEDRIC RANDAL BOULT, of H 11
Exchange Buildings, Liverpool, in the County of Lancaster, Merchant, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:--
This invention relates to improvements in signalling and has special reference
to the magnetic system of signalling for which Letters Patent numbered 17041
of 1893, 11773 of 1894, 2282 of 1895, 8724 of 1895, 20735 of 1895 and 29257 of
1897 have been granted to us.

page_text: One object of this invention is to effect an improved construction of and sup-
port or attachment for the road magnets. With a view to occupying but little
width of the roadway at or near rail level, and at the same time to afford great
protection to the magnets, we may according to this invention bury these (in
à more or less nearly vertical position) in a solid piece of timber placed edgeways
on the sleepers. The lower ends of the magnets may be connected either by other
magnets or by iron bars or plates with other vertical magnets or bars or with the
chairs (and so with the railway metal, as suggested in our Patent No. 17041 of
1893) for the purpose of reducing air gap "and guiding the magnetic flux to
the desired pole-plates of the armature. Since magnets may be placed in con-
nection with each rail both inside and outside there are four positions on the
road from which an armature relay can be operated while the width of roadway
occupied by the magnet supports is extremely small.
93
In view of the immense importance of the "danger" or "on" signals (which
we prefer to give by permanent magnets) and in view of the fact as hereinafter
explained that all necessary signals can be controlled by three armatures, we pro-
pose to utilize the fourth position on the road for duplicate sets of permanent
magnets the engine by preference carrying duplicate armatures in correspond-
ence. If the two outside or the two inside positions (on the engine or on the
road or both) are occupied by apparatus for giving the same signals
the corresponding circuits on the engine will be permanently right, whichever
end of the engine runs first; consequently they never need be interfered with, and
only the
off" connections require to be switched over for reverse running. If
two on armatures and duplicate magnets are used, one needle in each armature
will suffice and its movement will be stronger than if there were two: the con-
struction also will be somewhat simplified. Another object of this invention is
to provide an improvement in the general arrangement or scheme or signalling
whereby with only two armatures we are able to operate the following signals
vis two semaphores or their equivalents, two spot" or fault movements, and
three route indications. To do this we so connect the indicator movements that of
the four signalling circuits (after parallel needle circuits have passed the "spot"
coils, and united at least magnetically) two give the home and distant
signals respectively and each of the other two actuates a special route number
and a
common general "line-clear" signal (for instance, throws down both
semaphores at once). With suitably arranged electro-magnets on the road,
either or both of these numbers can be given. With only one electro-magnet
at each position either of two routes can be given. With another armature for
route numbers and two electro-magnets to each armature eleven different routes
may be given.
+
*
<<
"
on
"
""
To call attention to the movements of the signal indicator we prefer to use
two different toned bells (controlled by the distant and home semaphore tongues
respectively after the manner of an ordinary relay) arranged to ring while the
semaphores are in the "on" position and to stop ringing when the signals are
off. To enable the bells to be stopped by hand if so desired without inter-
ference with the signal indicator we may insert in the bell circuit a second relay
movement (preferably in an independent case) hereinafter referred to as the
push relay" to be closed by the signal current and capable of being opened
by hand; and in order that it may be impossible for the push relay to prevent
the ringing of the bell by an on" signal we prefer that the opening of the
relay shall be effected by a magnetic pull which will be neutralised by the
signal current. The apparatus we prefer to use is in form a modification of the
replacer push " described in the specification of our above-named Letters l'atent
No. 29257 of 1897. For our present purpose the apparatus comprises a polarized
pivotted relay tongue the free end of which plays between an iron core surrounded
by one or more coils traversed by the signal currents and a hinged or flexible
iron bar or equivalent preferably connected by an iron yoke with the polarising
magnet and the iron core. In its normal position the tongue is lying against an
**
"
on
در

page_text: Insulated contact in the end of the core (or equivalent device) so as to close the
bell circuit through the relay, the tongue being attracted to, but not quite touch-
ing, the iron of the core. To break the bell circuit the hinged iron bar (which
may be normally held back by a spring or otherwise) is pushed forward till it
touches the tongue (or more nearly so than the core does) which is then held or
attracted to the said bar more strongly than to the core. The bar being then
At any
moved away brings the tongue with it and the bell circuit is broken.
time during or after this movement of the bar by which the tongue is detached
from the insulated contact, any current in the coil will snatch away the
tongue from the bar and throw it against the said contact thus again closing the
bell circuit.
This device may be serviceable in signalling apparatus for a variety of pur-
poses where the signals are received by apparatus that has to be readjusted and
where it is desirable that the reception of a further signal during the readjusting
operation shall not be interfered with by that operation. For example it may be
employed in the signalling circuit of winding engines in mines and similar places
so that the engine attendant may stop his bell and yet be open to receive a second
signal whilst so doing.
Another improvement is in the construction of polarized relays such as we
use in the engine armatures for closing the signal circuits.
con-
According to our present invention we are able to place one or more needles
in one "gap" and to both polarize and control the same by means of one magnet.
By preference we pivot the needle at its centre and polarize and control both
ends, and we will describe the construction as so applied. We will consider one
needle only, placed in a gap in the iron bridge piece of an armature of the kind
described in our above mentioned Letters Patent No. 117783 of 1894. In order
that this needle may be normally held in the middle of its swing (or
irolled) without a special controlling magnet, spring etc., we make the sides of
the gap that is the width of the polar ends of the separated portions of the
bridge-piece, approximately equal to the length of the needle; we also by pre-
ference provide each of these polar ends with horns at its sides projecting in a
direction more or less nearly parallel to the needle, the tips of the horns lying
close to the ends of the needle. A permanent magnet is placed so that one end
of the needle and the two adjacent horns, one on each polar end, are magnetised
with north polarity and the other end of the needle and the horns adjacent thereto
with south polarity. The polar ends and needle thus form a system of three
similarly polarized magnets of which the central one is pivotted while the two
side ones are rigidly held, the former will therefore, as is well known, take up a
position of stable equilibrium, about equidistant from the two latter. Cross
magnetism due to road magnets will deflect the needle as described in our previous
Letters Patent herein before referred to.
It is evident that instead of using a separate permanent magnet to polarize
the needles and polar ends these may themselves be "permanently" magnetized.
The special feature of this part of our present invention is the application of what
may be described as a repulsion control" as distinguished from the attraction
control as previously employed.
Advantages accruing to this repulsion control are that the magnet adjustment
need not be nearly so fine as in an attraction control, the practicable swing of
the needle is greatly increased and the form of poles of the said magnet of minor
importance.
This method of control is broadly applicable to polarized relays for all signalling
purposes in general and particularly to those in which three significant positions
are desired.
In the accompanying drawings:-
Figure 1 is a plan of a portion of the track showing the improved arrangement
of magnets.
Figure 2 is a side elevation looking in the direction of the arrow in Figure 1.

page_text: Figure 3 is a longitudinal section on the line 3-3 of Figure 1.
Figure 4 is a transverse section on the line 4-4 of Figure 1 part of the
apparatus carried by the engine also being shown.
Figure 5 is a diagram showing the apparatus carried upon the engine and the
electrical connections of the various parts.
Figure 6 is a plan of one construction of a push-relay according to this inven-
tion, the cover being removed for the sake of clearness.
Figure 7 is a side elevation of the same.
Figure 8 is an elevation of the same at right angles to that shown in Figure 7,
the cover being indicated in section, and
Figure 9 is a bottom plan of one construction of an armature according to this
invention.
Like letters indicate like parts in all the drawings.
With reference first to Figures 1, 2, 3 and 4.
In
A are sleepers supporting by means of chairs A¹ the rails A².
Under the chairs A and in magnetic connection therewith are plates
of iron A, and upon these plates, and also upon the sleepers A, rest blocks
of wood B which support a piece of timber C placed edgeways upon them.
some cases the blocks B are dispensed with the timber C being placed directly
upon the sleepers. The timber Û is furnished with holes C in which are inserted
permanent magnets D or electro-magnets D'. It will be seen that the holes C¹
extend right down to the plates A so that the latter form yokes connecting the
lower ends of the magnets with the chairs A¹ and rails A2. In the case of the
permanent magnets D it is preferred to arrange them, as shown in Figure 2,
with their upper ends spaced at approximately equal distances along the timber C
while their lower ends converge in sets on to the iron plates A³. When electro-
magnets are used they may be inserted vertically in the holes C¹ and a pole-
plate D2 placed in contact with their upper extremities (see Figure 3). In either
case the result is a road-magnet of solid construction having an extended field
and occupying very little space transversely to the track. The timbers Care
provided with sloped or ramped" ends as at C2 and are held down to the
sleepers by bolts C³.
As shown in Figure 4 the permanent magnets D for giving the "on" or danger
signals are mounted on the outside of each rail and the polarity is preferably the
same in both cases, i.e. the upstanding ends of the permanent magnets are both
north poles the rails being the south poles or vice versa. By this means the same
danger signals may be given whichever end of the engine runs foremost.
66
"
F(Figure 4) are armatures" carried by the engine and serving to collect
and focus the lines of force from the magnets upon a deflectable needle, situated
in a gap in the armature. In the present illustration the armatures are of the
'compound" type described in the Specification of our Letters l'atent No. 29257
of 1897. Each of the armatures comprises three collectors F¹ carried upon
the engine in such a position that they pass over the permanent magnets, the
rails, and the electro-magnets respectively, and in the "bays" or spaces between
the collectors are bridge pieces F and boxes 13 which contain the deflectable
needles. The general construction of the " armatures forms no part of the
present invention, and one improved form will be hereinafter more particularly
described.
Figure 5 is a plan of the signalling connections carried by the engine. G, G¹,
G2, G3, are the deflectable "armature" needles working between contacts a, b
and c, d. The needles G and G¹ are actuated by the "danger" or "on" magnets
either needle sufficing to give the signal, and the needles G² G³ are for giving
"off" signals and for indicating routes.
th
H, J, and K are groups of indicator movements which may be similar to the
type described in the Specification of our prior Letters Patent No. 29257 of 1897.
Each group comprises électro-magnets or signal coils which when energized serve

page_text: ""
to make visual signals. As shown in Figure 5 the group H comprises two
danger coils H and H2 and one line clear" coil H3; the group J two signal
coils J¹ J² and a replacing coil J³; and the group K four signalling coils K¹ K² K
and K and a common replacing coil K. The construction of the pivotted
semaphore or equivalent which moves-to make the signal-between the various
pairs of coils, is not part of the present invention; two such semaphores are how-
ever shown diagrammatically at H, H5 (Figure 5) and it should be noticed that
in the case of the danger signal coils H H contacts H H are provided which
complete secondary circuits when the signal is given.
وو
Two batteries L, L' are provided for the signalling circuits and a third battery L²
is placed in a secondary circuit containing bells M and M. N is a "push-relay
hereinafter more particularly described, and O are switches for reversing the "off"
signal connections when the direction of running of the engine is altered.
Suppose now a magnet on the roadway causes the armature needle G¹ to be
deflected against the contact b, current would flow from the battery L', wire e,
needle G¹, contact b, and wires f and g to the danger signal coil H2; thence by
wire h to the replacing coil K³. After passing round the replacing coil K³ the
current flows, by the wire to the signal coil J2 and thence by wire k through
one winding of the push-relay N back to the battery L'.
If the duplicate danger-signal armature needle G is deflected against its con-
tact the same danger signal coil H2 is energized, but the current flows from the
battery L, not L', and thence by way of wire c¹, needle G wire f¹, wire g &c. to
the coils H2 and K. After leaving the replacing coil K the current passes by
the wire to the coil J¹ thence by the wire j' through the other winding of the
push-relay N back to the battery L.
When both the danger signal armature needles G and G¹ are deflected against
their corresponding stops bit will be readily seen that in addition to the coils H³
and K both the coils J and J2 will be energized. The absence of the signal or
spot" due to either of the coils or J2 while not interfering with the running
signals will serve as a "fault" signal i.e. an indication that one of the armatures
or magnets is not working properly.
When the armature needles G G are deflected against the other contacts a,
the current from the batteries L. L' passes through the wires, and m to the
signal coil H and thence by the wire to the "spot" coils J, J2 as before.
The passage of a current round the coil H draws the arm H' over and completes
a local circuit including the battery L³, wire o, bell M, wire parm H, frame,
wire push-relay N back to the battery. The bell M therefore rings when the
coil His magnetised, and in a similar way a signal through the coil H operates
the bell M. As hereinafter explained the ringing of the bells M, M¹ may be
stopped if desired by the push-relay N, but the receipt of another " on signal at
once recloses the bell circuit at the push-relay and causes the bell to start
again.
61
"
The "off," or line clear" and "route" signals are given by means of the
armature needles G² and G³. There are four signalling circuits ²², and
controlled by the reversing switches and connecting the signal coils K1, K2, K³,
and K with the contacts c and d of the armature needles, G and G³. After
passing the coils K¹ K2 K and K the circuits join at the wires, pass through
the line clear coil H3 and the replacing coil down through the wire or k
and the push-relay N to the battery L or L'. Thus the effect of a deflection of
the needles G2 G3 is to cause one of the coils K' K² K³ or K to be energized and
thus to give a "route" signal, to indicate line clear on both semaphores and
also to replace both the spot signals."
Figures 6, 7 and 8, illustrate one construction of "push-relay" N according to
this invention.
pon a base N¹ is mounted an iron yoke N2 carrying an iron core N³ and a
permanent magnet N The iron core X is wound with two coils which are how-
ever merely indicated by the bobbin N in the drawings. Pivotally mounted

page_text: upon the permanent magnet N and polarized by it is a tongue No one end of
which carries a contact № and normally rests upon another contact N8 insulated
from the iron core N³. №9 is an iron bar hinged to the yoke N2 as at N10 and
having a projection N extending down towards the polarized tongue No. The
bar № is provided with a push N which passes up through a watertight
diaphragm N¹ and out through a hole in the cover N14.
Terminals N are furnished for the windings of the core №3 and for the
contacts upon the tongue N° and the core. The normal position of the bar N°
is indicated by dotted lines in Figure 8, it is kept in this position by a spring N16
The operation of the device is as follows, assuming the tongue No to be resting
upon the contact N8 on the core N³:-If the push N2 is depressed the pro-
jection N upon the iron bar No is brought into contact with the polarized
tongue No, the latter is accordingly attracted more strongly by the bar than by
the core which it is not allowed to quite touch and, when the push is released
the tongue returns with the bar No and opens the circuit between the contacts N7
and N8. It will be seen that should a current pass through either of the wind-
ings upon the iron core N³ the distribution of the magnetic flux will be
immediately altered and the tongue N6 returned to its position on the contact.
When applied to the particular scheme illustrated in Figure 5 the circuit
containing the bells M or M¹ and the battery L2 is closed when the tongue N
is down, when however, it is raised by the bar No the bell circuit is broken, but
is at once made again by the reception of a fresh signal.
Figure 9 is a bottom plan of one construction of armature according to this
invention. The pivotted needles G are placed parallel to one another in a gap G*
formed between two portions G of the iron bridge-piece of the armature. The
tips of the polar horns G6 project as far as the ends of the needles and the horns
and needles are polarized by a permanent magnet G7. Contact pillars G8 are
provided and both needles are preferably furnished with contacts as shown on
the right hand needle at G. The special feature of this portion of the invention
is the arrangement of the needles, pole-pieces and magnets so that both ends
of the needles are acted upon, and the control is effected by "repulsion" in the
manner herein before referred to.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is-
1. In railway signalling the employment of duplicate magnets or armatures
or both so that the same signal is received without altering the connections which-
ever end of the engine is running foremost.
2. In railway signalling a road magnet formed by inserting or embedding
magnets such as 1 1 in a support upon the road-way substantially as described
and illustrated in Figures 1, 2, 3 and 4 of the accompanying drawings.
3. In railway signalling the complete arrangement of magnets connecting
plates chairs and rails substantially as described or illustrated in Figures 1, 2, 3
and 4 of the accompanying drawings.
4. In railway signalling giving a common or general line clear signal on two
or more semaphores or equivalent which give separate danger signals.
5. In railway signalling the complete system of electrical connections sub-
stantially as described and illustrated in Figure 5 of the accompanying drawings.
6. In a "push-relay" the combination of a permanent magnet a magnetic core
magnetically connected thereto a winding upon the core a polarized pivotted
tongue and a movable magnetic arm or equivalent arranged and operating sub-
stantially as described.
7. The complete "push-relay" substantially as described or illustrated in
Figures 6, 7 and 8 of the accompanying drawings.
8. In a signalling relay controlling the needle by the mutual repulsion between
it and a similarly magnetized adjacent pole piece substantially as described.

page_text: 9. A signalling relay having a deflectable polarized needle, placed in a gap
between pole pieces which act upon both ends of it substantially as described.
10. A signalling relay having two parallel deflectable needles placed in a gap
between pole pieces which act upon both ends of the needles both needles and
pole pieces being similarly magnetised by one or more permanent magnets.
11. The complete bridge-piece for an armature" substantially as described
or illustrated in Figure 9 of the accompanying drawings.
Dated this 27th day of June 1899.
BOULT & WADE,
Agents for the Applicants.