Improvements in or relating to Automatic Safety Devices for Electric Currents.
Year: 1895

page_text: Date of Appl.cation, 18: June, 1895
Complete Specification Left. 13th Jan., 1896-Accepted, 15th Feb., 1896
PROVISIONAL SPECIFICATION.
Improvements in or relating to Automatic Safety Devices for
Electric Currents.
We, JAMES BARNS STONE, Machinery Agent, and SAMUEL BARNES,
Electrical Engineer, both 135 Finsbury Pavement in the City of London, do
hereby declare the nature of this invention to be as follows:-
This invention relates to devices adapted to take the place of the ordinary fuses
commonly employed to break the circuit in electric circuits when the current
exceeds the capacity of the apparatus. The details may be considerably varied
without departing from the spirit of the invention, but the following description
will serve to indicate the nature of the invention.
We employ one or more, conveniently two, solenoids arranged in a suitable
frame having an armature operating in conjunction with them, and the arrangement
being such that the distance between the poles of the solenoids and the armature
can be varied so that up to a certain strength of current the armature is not
operated, but should the current exceed that strength the armature is operated and
the mechanism presently to be described comes into use and breaks the circuit.
We prefer to regulate what we may term the load, that is the strength of current
to which the instrument is set by varying the distance as above explained between
the solenoids and the armature, but if preferred this may be effected by loading the
armature by weight, spring or friction so as to obtain the same result.
The armature may be arranged in any convenient manner but we obtain satis-
factory results by forming it as an angle lever pivotted at or about the angle, so
that when the armature is attracted it turns about its centre moving the other arm
of the lever which may be longer and thus releasing a latch or detent which under
ordinary circumstances and an ordinary pressure of current holds the armature
away from the solenoids.
The
Pivotted or otherwise suitably carried, but preferably pivotted upon the frame
which carries the solenoids is a movable bracket, bridge or quadrant preferably
provided with an insulated handle and having two contacts through which the
current passes in at one and out at the other; when these contacts are closed
the current passes but when they are broken the current ceases to pass.
previously described latch normally holds this bridge with the contacts completed
and the current passing, but should the armature operate and the latch be released
the bridge under the operation of any convenient spring or weight automatically
separates the contacts thus cutting off the current. The contact faces may be of
any convenient description say solid projections from the bridge fitting between
brushes or the like, but so long as proper contact is effected this is immaterial.
A special arrangement however is adopted to prevent sparking and burning of the
contacts, a convenient way of effecting this being to provide each member of each
contact with a piece of carbon or other suitable material arranged under spring or
other pressure to drag along in contact as the bridge breaks the ordinary contact
under the influence of its spring when released. A suitable means of carrying this
into effect is to pivot a bracket for each contact upon the bridge into which one of
the carbons is inserted and held by a binding screw a spring operating at the pivot
so as to cause this member of the carbon contact to press upon the other member
thus ensuring contact and continual passage of the current until the regular

page_text: contacts are released and are thus saved from burning after which the carbon
contacts separate it being immaterial if sparking or burning occur to these.
In order to prevent the bridge when released from falling back into engagement
means are provided to hold it in the position it reaches after the contacts are
broken; this may be effected in various ways, but a simple plate spring or other
form of detent will accomplish this object.
In order that the point at which the instrument is set to break the current may
be known we may employ any convenient arrangement of scale and setting screw
or device; the various screws and means for adjusting the positions of the various
parts of the strength of the springs may be employed as required.
When this invention is to be employed with alternating currents it is necessary
to provide means to prevent the over-heating and burning of the parts of the
solenoids; this we effect by making the cores of the solenoids laminated or in
pieces preferably by rivetting together a number of thin plates with sufficient
insulating material between them and thoroughly coating and protecting them with
insulating material conveniently vulcanized fibre. The coils of the solenoid also
should be well insulated.
Instead of the bridge previously mentioned a spring-operated rotating disc may
be employed for the same purpose and operating substantially in the same manner
the disc being held normally in the position for the closed circuit, by detents
released by the operation of the armature substantially in the same manner as
already described, the permanent contact and the temporary contacts being used
substantially as before, but with the variations in detail necessary to the use of the
disc instead of the bridge. The disc may be hollow and made of insulating
material but instead of a complete disc pivotted arms could be employed as well as
the necessary spring devices in connection with the contacts, the rotating disc or
arms or the like. This arrangement is peculiarly suitable for use with tram-cars
and the like where the great shaking might cause the improper release of the
detent and the operation of the apparatus when not required.
Dated this First day of June 1895.
BOULT & WADE,
Agents for the Applicants.
Improvements in or relating to Automatic Safety Devices for
Electric Currents.
We, JAMES BARNS STONE, Machinery Agent, and SAMUEL BARNES,
Electrical Engineer, both of 135 Finsbury Pavement, in the City of London, 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 :-
This invention relates to devices adapted to take the place of the ordinary fuses
commonly employed to break the circuit in electric circuits when the current
exceeds the capacity of the apparatus.
The construction of the devices is such that they are inoperative until a certain
strength of current is reached, but should the current exceed that strength,
mechanism such as will presently be described comes into use and breaks the
circuit. We prefer to provide in the apparatus, means for readily regulating from
time to time what we may term the "load that is to say the strength of current
at which the device is desired to operate, in order that a given instrument may
have a wide range of effectiveness and not be confined to use for one strength of
current only.

page_text: In a device constructed according to this invention we may if desired, not only
interrupt the circuit when a predetermined limit of current is reached, but
preferably cause, in addition, the resistance of the circuit to be automatically
increased, just prior to its interruption so that at the instant of interruption there
shall be little or no sparking at the contacts.
In the accompanying drawings
Fig. 1 is a perspective view of one construction of device according to our
invention, with its movable parts in the positions they occupy when the circuit is
interrupted.
Fig. 2 is a vertical and approximately central section of Fig. 1, showing in
dotted lines certain of the movable parts in the positions they occupy when the
circuit is just about to be broken or to be made, the same parts being shown in
full lines in the positions they occupy when the circuit is complete.
Figs. 3 to 10 are views hereinafter particularly described, of an alternative
construction of apparatus according to this invention.
Like letters indicate like parts throughout the drawings.
With reference first to Figs. 1 and 2, A is a slab of marble or the like
constituting the base of the instrument.
B is a metal frame secured to the base.
C is a metal contact-making device, hereinafter termed a "bridge," pivotted by
screws C to the frame B from which it is insulated by annular washers D of
insulating material which encircle the screws C¹ in order that those screws may
not electrically connect the frame B and the bridge.
E and F are each a double contact secured to the base; they are included in
the electric circuit governed by the instrument..
G G are the leads or conductors of the circuit so connected to the contacts E
and F respectively that the space between those contacts, is a gap in the circuit.
except when electrically bridged by the bridge C.
The contact E comprises. spring jaws E and an adjustable and removable
strip E2 of carbon which is held by a screw E 3 in a sleeve E4 forming part of
the contact.
The contact F comprises, similarly, spring jaws F', a strip F 2 of carbon
a screw F 3 and sleeve F4 to hold the carbon strip F 2.
The bridge C comprises extensions C2 C3; the extensions C2 C3 are adapted!
to enter and be gripped by the jaws E' F' respectively so as to make a good
electrical connection therewith; the bridge carries also pivotted carbon strips H I
respectively adapted to make electrical connection with the fixed carbon
strip E2 F 2. The carbon strip H is retained in a sleeve H' by a screw H 2 the
sleeve being provided with a spindle H 4 free to turn in bearings H5 H6 on the
bridge C. H7 is a spring which is secured at one end to the bridge and at.
the other end to the spindle H4 and tends always to turn that spindle and its.
sleeve H in the direction of the arrow a in Figs. 1 and 2. H 8 is a pin fixed in
the spindle H 4 and serving to prevent the movement of the spindle end wise in
its bearings as well as to limit its movement of rotation in the direction of the
arrow.
The carbon strip I has appurtenances 11 to 18 similar in all respects to the
appurtenances H to H 8 of the strip H.
J is an insulated handle attached to the bridge C by which the latter can be
raised and lowered manually; a part J' of the handle projects downward from
the bridge, for a purpose hereinafter set forth. J2 is a plate spring fixed to a
projection B of the frame B to hold the bridge C up by means of the handle .J
when the bridge is put into the position in which it is shown in Figure 1.
C4 is a projecting tongue fixed to the bridge so as to engage with a detent U
hereinafter again referred to.
K is a small dash-pot or cylinder secured to the base A within a casing K¹ of
insulating material and containing a piston L free to reciprocate in the cylinder
its upward movement is limited by a flange or head L2 on the piston-rod L

page_text: and its downward movement is retarded by a spring K 3 which is in compression
below it as shown.
C5 is a screw adjustable in a lug C6 on the bridge and adapted when the
bridge is depressed, to force down the piston L against the resistance of the
spring K 3 as in Figure 2.
The dash-pot K and screw C 5 can be dispensed with if desired.
M is a screw by which the lead G is electrically connected to the contact E.
N, Figure 2 is a metal strip by which the other contact F is connected to a conducting
post fixed to the base. G 2 are the windings of an electro-magnet P presently
to be described; they connect in parallel the post O with another post O¹, which
latter is secured to the base A and provided. with a screw 02 to which the
lead Gis electrically connected.
The electro-magnet P comprises cores P¹ encircled by the windings G2 which
do not touch them and fixed to a keeper P 2 the ends P3 of the cores P¹ slide in
holes made in guide brackets B 2 forming part of the frame B. The keeper has
an adjusting-screw Q screwed into a tapped hole therein; this screw has a milled
head Q' secured upon it and passes through the projection B₁ on the frame B,
being prevented from having axial movement by the milled head on the one
hand and by the collar Q2 on the other, which latter is of larger radius than
that of the hole in the projection B₁ through which the stem of the screw Q is
passed.
By rotating the screw Q the cores P¹ can be adjusted lengthwise within their
windings G 2. P 4 is a graduated plate fixed on the keeper P 2, and B 4 is an
index finger fixed to the projection B so that the adjustment of the keeper P 2
and cores P' by the screw Q can be made in accordance with the graduations.
R is an armature in close proximity to the ends P 3 of the cores P¹. It forms
part of an angle-lever S pivoted near the angle by pointed screws T which pass
through lugs B 5 formed on the frame B and engage with the ends Si of
trunnions S2 formed on the lever S; the lever is free to oscillate on its trunnions
through a small angle, limited in one direction by the ends of the cores P 3 or the
adjacent faces of the brackets B2 which are in the path of movement of the
armature and limited in the opposite direction by an adjustable stop screw S 3
which projects from one arm $4 of the angle lever so as to come against the
base A or a fixed part of the instrument when the lever S is tilted sufficiently.
R¹ is a non-conducting knob on the armature R to enable the lever S to be
oscillated by hand when desired.
The arm S4 of the angle-lever S has jaws S 5 at one end between which the
pin S6 extends, and at the same end it is provided with a plate S7 carrying
pins S8 S 9.
Below the arm $4 and secured to the base A is a plate A¹ to which are pivotted
a detent U and a lever V by pins U₁ and V₁ respectively. The detent U passes
between the pins S8 and S9 as shown, and is hooked at U 2 to engage with the
bereinbefore-mentioned tongue C4 on the bridge C; it is bevelled at U 3 above
the hooked portion, and curved at its opposite sides so as to have cam-surfaces
at U 4 and U 5 the first of which is in proximity to the pin S8 and the second of
which is in proximity to the pin S 9. The lever V is bevelled at its upper end
at V and V 2 so that a sharp angular portion is produced at V3 between the
bevels to bear against the pin S6 in the jaws $5. At the lower end of the
lever V is a tongue V 4 turued up as shown So that a spring W fixed to
the plate A bears upon it and acts to keep the edge V 3 pressed against the
pin $ 6.
We will now proceed to describe the operation of the device shown in Figures 1
and 2 assuming to commence with that the parts are in the positions in which they
are shown in Figure 1, and that the cores P¹ have been adjusted to the desired
extent by means of the screw Q to regulate the "load of the instrument as
aforesaid. The handle J is grasped and the bridge C turned thereby into the
position in which it is shown in full lines in Figure 1; in the course of this

page_text: movement the pivoted carbon strips H and I come into contact with the fixed:
carbon strips E2 F 2 respectively in the manner indicated by the dotted lines in
Fig. 2, thereby completing the circuit from the lead G to the contact E and by
way of the strips E 2 and H, bridge C, strips I and F 2 contact F, strip N,.
post O, windings G2 and post O' to the other lead G¹. While the downward
movement of the bridge continues the strips H and I with their spindles H4 [4
are turned in the bearings on the bridge against the resistance of the springs H 7 17
and therefore so react on the strips E2 F2 as to tend to raise the bridge C to
break the circuit, and in the further continuance of the downward movement of
the bridge the metallic extensions C2 C3 thereof enter and are gripped by the-
jaws E F¹ of the contacts E F so that the circuit through the bridge ultimately
includes not only the strips H E 21 F2 but also the parts C2 E C3 F¹ "in
parallel with the strips.
"
As soon
as the bridge has been pressed down sufficiently far to force the
extensions C2 C3 into the jaws E Fit will have brought the tongue C4 into a
position in which the detent U can engage with it, and the extension J¹ of the
handle J will depress slightly the arm S4 of the angle lever S (which must.
previously have been elevated as will presently be explained) and in doing so will
draw the armature R away from the ends P3 of the cores P1 and move the.
pin S 6 past the angular portion V 3 of the lever V, whereupon the bevel V 2 will
be caused by the spring W to depress the arm S4 still further, and that arm in its.
further descent forces the pin S9 to ride down over the cam-surface U 5 and
thereby moves the detent U into engagement with the tongue C4 holding the.
circuit closed against the action of the springs H 7 I7 and also against the action.
of the dash-pot spring K 3 which in the descent of the bridge C will have been.
compressed by the screw C5 which projects from the bridge.
The lever V is not essential but its use is desirable inasmuch as it moves the-
armature R, arm S4 and the mechanism operated thereby to either extreme of
their travel, forcibly and with certainty, whenever their movement is started by
other means, and thus the parts in question are prevented from taking up any
neutral position likely to interfere with the proper action of the apparatus.
When the current in the circuit of the instrument (in which the windings G 2
are included as aforesaid) exceeds the "load" limit for which the cores are adjusted.
the armature R will be attracted towards the ends P3 of the cores P', and the
arm S4 of the lever S will thereby be lifted to move the pin S6 up past the
angular portion V 3 of the lever V whereupon the bevel V will be caused by
the spring W to elevate the arm S4 and that arm in its further ascent forces the
pin S 8 to ride up over the cam-surface U 4 and thereby frees the detent U from
engagement with the tongue C 4. Immediately that the tongue C 4 is thus freed the
springs H 7 17 K 3 fling the bridge sharply up until its handle J is caught and
retained by the spring J 2 as shown in Fig. 1. Any other suitable retaining.
device may be employed instead of the spring J.
As the bridge Crises the extensions C2 C3 thereof leave the jaws E' F' of the
contacts E F before the strips H and I break contact with the strips E2 and F
so that any sparking that might occur when the bridge is taken out of the circuit,.
which will then have a gap in it between the contacts E and F, will take place at
the removable and renewable strips and not at the jaws E' F'. Moreover the
strips H and I in moving to break the circuit travel upon the strips E2 F 2 in a
direction away from the sleeves E 4 F 4, so that during that travel the length of
carbon included in the circuit continuously increases up to the instant of interrup-.
tion, and conversely the current continuously decreases so that sparking at the
break is minimised or obviated.
If by any chance the armature R should be away from the poles P of the
electro-magnet P when the bridge C is depressed the arm S 4 will be down and
therefore the detent U will be held immovable in the path of the tongue C 4;.
consequently it is necessary to move the armature R up to the cores P₁ in order to

page_text: be able to get the tongue, into the position in which the detent can engage it, and
when the armature is thus moved up the arm S 4 moving with it is then necessarily
elevated. Whenever it is so elevated the projection J¹ from the bridge handle J
cannot fail to operate it to produce a positive latching of the bridge provided that
the latter is moved far enough to properly complete the circuit. Thus we make it
impossible to latch the bridge at all unless such prior adjustment of the arm S 4
is effected as will make the locking automatic and certain.
Instead of the bridge previously mentioned a spring-operated rotating disc may
be employed for the same purpose and operating substantially in the same manner
the disc being held normally in the position for the closed circuit, by detents
released by the operation of the armature substantially in the same manner as
already described, the permanent contact and the temporary contacts being used
substantially as before, but with the variations in detail necessary to the use of
the disc instead of the bridge. The disc may be hollow and made of insulating
material but instead of a complete disc pivoted arms or an arm suitably counter-
balanced could be employed as well as the necessary spring devices in connection
with the contacts, the rotating disc or arms or the like. This arrangement is
peculiarly suitable for use with tram-cars and the like, where the great shaking
might cause the improper release of the detent and the operation of the apparatus
when not required. It is shown in Figs. 3 to 10, wherein
Fig. 3 is an elevation of a tramway switch constructed according to this
invention.
Fig. 4 is a similar view with the disc removed for the sake of clearness.
Fig. 5 is a view of the lower part of Figs. 3 and 4, with part of the magnet, the
armature and part of the latch in section.
Fig. 6 is a perspective view of the stationary contact.
Fig. 7 is a perspective view of the movable contact which makes electrical
connection with the stationary contact Fig. 6.
Fig. 8 is a section on the line 8 8 of Fig. 4.
Fig. 9 is a plan of a modification of the tramway switch.
Fig. 10 is a section on the line 10 10 of Fig. 9.
Figs. 3 to 10 are drawn to a smaller scale than that of Figs. 1 and 2.
With reference now to the modification illustrated by Figures 3 to 8 the bridge C
is replaced by an equivalent in the shape of an arm C 6 secured to a flanged disc C7
which latter is preferably of insulating material. C¹ is a pivot secured to the
base A for the arm C6 and disc C7 to turn on. K³ is a spring attached at one
end to a lug on the pivot C¹ and at its other end to the arm C6 so as to tend
always to turn the arm in the direction of the arrow, Figs. 3, 4 and 7. H is a
carbon strip carried on a sleeve H¹ pivoted at H 4 to the arm C 6 and controlled
by a spring H7 much in the same manner as the pivoted strip H' in Figs. 1 and 2.
E is a double contact the jaws E of which make contact with a projection C 2
from the arm C6; the fixed carbon strip E 2 which also forms part of the contact E
makes contact with the pivoted strip H.
J is a handle whereby the disc C7 can be rotated to bring the arm C 6 into the
position in which it is shown in Fig. 3 to complete the circuit, the course of which
is from the contact E strips E 2 and H through the arm C 6 and thence out of the
instrument by way of its pivot which is suitably connected with the other side of
the current.
The lever V, spring W and roller S 6 correspond to the correspondingly-lettered
parts in Figs. 1 and 2. The latch is constituted by a detent U pivoted to the
main frame of the apparatus and adapted to engage by means of a hook U 2 at
its end with a projection C 4 on the circular disc C 7. An arm S4 forming
part of the armature R of the electro-magnet P. carries two pins $9 $ 10, one S9
of which is normally below the detent U and in proximity to a notch or recess Y
in the said detent (as in Fig. 3) so that when the arm S4 is operated by the
electro-magnet P the pin S9 is moved into line with the notch or recess Y and

page_text: allows the detent U to drop away (under the action of gravity) from the projec-
tion C4, whereupon the disc C 7 is free to rotate and break the circuit.
The end of the arm S 4 is bevelled or curved as at S11 in order that the projec-
tion C 4 in its return with the disc C7 (when the latter is re-adjusted in a direction
opposite to that indicated by the arrow in Fig. 3 to re-close the circuit) may strike
against the bevelled portion and so push the arm S 4 that the armature R is moved
away from the electro-magnet. In so moving the arm S4 the pin S 10 lifts the
detent U, thereby raising it clear of the pin S9 which had previously been in the
recess Y and proceeds to force the detent U into positive engagement with
the projection C4 to retain it thus engaged in spite of any shocks or jars until
the armature R is again operated. During this adjustment of the detent U by the
pin S 10 the pin S9 will have been placed as in Fig. 3 in proper position away
from the notch or recess Y in readiness for a further operation of the apparatus.
When the current operates to release the latch the circuit is broken at C2 E¹ but
remains closed through H' E2 at which points it is next broken immediately after
an increase of the resistance of the circuit (just as in the apparatus hereinbefore
described with reference to Figs. 1 and 2) the spring K 3 operating to rotate the
disc arm C6 and C7 quickly in a direction which is indicated by the arrow in
Figures 3 and 4.
C8 is a projection on the disc and A 2 a spring secured to the frame in order
that the projection C8 may engage with it and prevent the disc from being thrown
too far by the spring K 3.
.
In the modification illustrated in Figures 9 and 10 the disc C7 is absent, the
pivot or centre-pin Con which the arm C 6 turns being placed within a stationary
annular cell C9 of insulating material over the edges of which the bridge
and contact-making devices extend as shown, being turned down over the wall
of the cell, which wall then becomes an insulating guard against the short-
circuiting.
Instead of varying the "load" by adjusting cores within windings we may make
the windings movable or connect them by flexible connections with their terminals
and adjust them relatively to fixed cores. Or for a like purpose we may adjust the
whole electro-magnet relatively to its armature or vice versa or employ an armature
which may be controlled by a weight, a spring, or by friction.
We may provide means for adjusting the strength of the springs in the apparatus
to the desired extent and we may provide springs to operate the bridge C or its
equivalent distinct from those to which reference has herein before been made.
And instead of a single circuit arranged to be interrupted at two places (as
at E and F in Figures 1 and 2) we may insulate the opposite sides of the
bridge C from each other and arrange it to control two circuits in one of which
the contact E and one side of the bridge will be included, the other side and
the contact F being in such case included in the other circuit.
Or we may
otherwise arrange the circuits and connections, and vary the details of the
apparatus without departure from this invention. Obviously we may easily
arrange the electro-magnetic latch to release the armature as soon' as
current in the apparatus passes a certain minimum instead of maximum limit.
In such a case we could for instance arrange for the armature R to be normally
held against the electro-magnet poles so long as the current exceeded a certain
limit, and that the armature should fall when the current weakened to the
desired degree. Further the armature would then be so coupled to the angle-
lever S (Figs. 1 and 2) that the latter would rise when the armature fell.
the
When this invention is to be employed with alternating currents it is necessary
to provide means to prevent the over-heating and burning of the parts of the
solenoids; this we effect by making the cores of the solenoids laminated or in
pieces preferably by rivetting together a number of thin plates with sufficient
insulating material between them and thoroughly coating and protecting them
with insulating material, conveniently vulcanized fibre. The coils of the solenoid
also should be well insulated.

page_text: 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. The automatic breaking or disconnecting of an electric circuit by the current
in the circuit itself when that current passes any predetermined limit within the
range of adjustment of the instrument.
2. In an automatic electric switch the combination with the bridge C of an
-electro-mechanical latch constructed to release the bridge when the current passes
a predetermined limit and means such as described which when the bridge is in the
closed-circuit position tend always to operate the bridge and cause it to interrupt
the circuit.
3. In an automatic electric switch an electro-magnetic releasing-device
adjustable to operate when any predetermined limit of current within a given
range is passed, with or without a scale and index to denote the limit to which it is
-adjusted.
4. In an automatic electric switch an electro-magnetic releasing device wherein
the load-limit is variable by adjusting-devices substantially as described.
5. In an automatic electric switch a latch which is moved into engagement
with the bridge by the action of the bridge itself substantially as described.
6. In an automatic electric switch a latch which is moved into engagement
with the bridge by the action of the bridge itself, and is so constructed that it
interferes with the operation of the bridge unless part of the latch mechanism
receives such a preliminary adjustment as ensures the subsequent latching
substantially as described.
7. In an automatic electric switch the combination with the apparatus claimed
in the 5th claiming-clause of a spring-controlled lever such as W to move the
armature and the mechanism connected therewith positively to either extreme of
its travel and prevent it from retaining an intermediate position substantially as
.described.
8. In an electric switch having contacts which to break the circuit withdraw in
succession from it, the employment of one or more contacts to produce an
increase of resistance in the circuit before finally breaking it substantially as
-described.
9. In an antomatic electric switch a contact such as H pivotted to a bridge C
and provided with a spring H7 substantially as and for the purpose described.
10. In an automatic electric switch a bridge C formed as or combined with a
disc or otherwise constructed symmetrically or balanced, with or without means
for preventing the over-running thereof, substantially as and for the purpose
.described.
11. In an automatic electric switch the combination with the bridge and
mechanism for automatically raising the same of a spring such as J 2 or other
retaining device substantially as aud for the purpose described.
12. In an automatic electric switch a latch arranged and operating substantially
as and for the purpose described and illustrated in Figures 3 and 4 of the accom-
panying drawings.
13. The combination and arrangement of parts constituting a complete
automatic switch substantially as and for the purpose described and illustrated
in Figures 1 and 2 or Figures 3 to 8 or Figures 9 and 10 of the accompanying
drawings.
1
71
T
1000
BOULT & WADE,
Agents for the Applicants.