An Improved Means or Apparatus for Reducing or Extinguishing the Electric Arc Formed on Breaking Electrical Circuits.
Year: 1899

page_text: Date of Application, 31st Jan., 1899
Completo Crocification Loft 31st Oct 1800 Accented 6th Jan
1900
An Improved Means or Apparatus for Reducing or Extinguishing the
Electric Arc Formed on Breaking Electrical Circuits.
I, RICHELIEU Acock, 31, Sholebroke View, New Leeds, Estimator, in the County
of York, do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved means or apparatus for reducing or
extinguishing the destructive arc, formed on breaking metallic connections while
acting as circuits for electrical energy. The invention is especially useful for and
applicable to electrical switches, controllers, cut outs or fuses, commutator
brushes and the like apparatus.
The invention consists in inserting the metal contact pieces in any
suitable insulating substance in such relation to the metal that their
respective faces, as they leave one another shall be followed up by the insu-
lating substance, the insulating substance being so disposed as may be found
necessary to suit the various designs in which this invention is capable of being
carried out. For example, if two flat plates are arranged in the ordinary way to
make sliding contact with each other, and a relative movement takes place, an
arc would follow at the instant of parting, as is well known, the electrical energy
arcing across an intervening air space, varying in distance with the force of the
current, and sometimes fusing the adjacent edges of the plates. By my inven-
tion, however, I provide insulating material where the air space would otherwise
be, the insulating material being made to conform to the plane of motion fol-
lowed by the metal plates, whether that be flat or curved. Consequently, the
arc is chilled, damped out, or extinguished not only by its immediate contact
with an insulating material, more or less uninflammable, and a bad conductor
of heat, but also the arc has practically no room to form, any tendency in that
direction being checked by the close fitting of the insulating surfaces, which may
also form contact and continuous bearing surfaces to each other and to the
metallic plates used for conducting electric energy:
It will be apparent that my invention may be applied to various forms of elec--
trical apparatus, the varieties of switches alone being very numerous.
Con-
sequently it will be sufficient to say that whether the contact surfaces are flat
or curved, or the movement imparted in making or breaking contact is in a
straight line or of a rotary character, my invention is applicable, and it would
provide a combined and continuous bearing of the metallic and insulating material
fitted closely together for at least the distance to which an arc might reach, and
this distance would vary according to the potential difference between the ter-
minals or electrodes which form the contact points.
The metallic points or contacts employed are all so combined and arranged with
the aforesaid insulating material that they are capable of making good electrical
contact with each other and may also come in contact with any opposing surface
of the insulating material, when electrical contact is broken. For this purpose
I may suitably form one or more of the metallic contacts so as to make spring

page_text: pressure with the aforesaid opposing surface, or place a spring or springs behind
the said contacts to force them in the desired direction, or use weights or lever-
age for the same purpose. My invention is applicable to any number of poles
or contacts and any degree of potential required, and I sometimes vary the
nature of the insulating material according to the difference of potential so as
to make the material more refractory as the potential becomes greater, and may
attach the insulating material rigidly to the electrical contacts, or as in the case
of the movable electrical contact may mount all or part on to a separate carrier
so as to follow the moveable contact wholly or partly as may be desired.
Furthermore, I sometimes construct or arrange my improved means or appa-
ratus to operate in a bath of oil in order to further damp or extinguish the electric
arc when formed, the bath also serving to fill up any irregularity or air spaces
between the moving parts.
Dated this 30th day of January 1890
An Improved Means or Apparatus for Reducing or Extinguishing the
Electric Arc Formed on Breaking Electrical Circuits.
I, RICHELIEU ACOCK, of 19, Aysgarth Road, Dulwich Village, in the County of
Surrey, and late of 31, Sholebroke View, New Leeds, in the County of York,
Estimator, 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:-
My invention relates to an improved means or apparatus for reducing or
extinguishing the destructive are formed on breaking metallic connections while
acting as circuits for electrical energy. The invention is especially useful for and
applicable to electrical switches, controllers, automatic cut outs, commutator
brushes and the like apparatus. The invention consists in inserting the metal con-
tact pieces in any suitable insulating substance in such relation to the metal that
their respective faces, as they leave one another shall be followed up by the insu-
lating substance; the insulating substance being so disposed as may be found
necessary to suit the various designs in which this invention is capable of being
carried out. For example if two flat plates are arranged in the ordinary way to
make sliding contact with each other, and a relative movement takes place an
are would follow at the instant of parting as is well known the electrical energy
arcing across an intervening air space varying in distance with the force of the
current, and sometimes fusing the adjacent edges of the plates. By my inven-
tion however I provide insulating material where the air space would otherwise
be, the insulating material being made to conform to the plane of motion fol-
lowed by the metal plates, whether that be flat or curved. Consequently, the
are is chilled, damped out, or extinguished not only by its immediate contact
with an insulating material, more or less uninflammable, and a bad conductor
of heat, but also the arc has practically no room to form any tendency in that
direction being checked by the close fitting of the insulating surfaces, which may
also form contact and continuous bearing surfaces to each other and to the
metallic plates used for conducting electric energy.
Con-
It will be apparent that my invention may be applied to various forms of elec-
trical apparatus, the varieties of switches alone being very numerous.
sequently it will be sufficient to say that whether the contact surfaces are flat
or curved, or the movement imparted in making or breaking contact is in a

page_text: straight line or of a rotary character, my invention is applicable, and it would
provide a combined and continuous bearing of the metallic and insulating material
fitted closely together for at least the distance to which an arc might reach, and
this distance would vary according to the potential difference between the ter-
minals or electrodes which form the contact points.
The metallic points or contacts employed are all so combined and arranged with
the aforesaid insulating material that they are capable of making good electrical
contact with each other and may also come in contact with any opposing surface
of the insulating material, when electrical contact is broken. For this purpose
I may suitably form one or more of the metallic contacts so as to make spring
pressure with the aforesaid opposing surface; or place a spring or springs behind
the said contacts to force them in the desired direction, or use weights or lever-
age for the same purpose. My invention is applicable to any number of poles
or contacts and any degree of potential required, and I sometimes vary the
nature of the insulating material according to the difference of potential so as
to make the material more refractory as the potential becomes greater, and may
attach the insulating material rigidly to the electrical contacts, or as in the case
of the movable electrical contact may mount all or part on to a separate carrier
so as to follow the moveable contact wholly or partly as may be desired.
Furthermore, I sometimes construct or arrange my improved means or appa-
ratus to operate in a bath of oil in order to further damp or extinguish the electric
are when formed, the bath also serving to fill up any irregularity or air spaces
between the moving parts.
In order that my invention may be the better understood, I now proceed to
describe the same in reference to the drawings herewith, in which, like letters
refer to like parts, throughout the various figures.
Figs. 1 & 2 Sheet J, show in sectional elevation and plan one form of switch
embodying my invention.
A is an insulating base and as usual is the fixed portion of the switch. Bare
the four terminal contacts bolted or otherwise fixed to A. The lower portions of
the contacts B are provided with nuts to secure the cable or the thimble to which
the cable may be sweated. C is an external cover also of insulating material
and is kept in position by having suitable projections engaging with correspond-
ing recesses in the fixed base A. 1) is a disc of insulating material mounted
upon the square sleeve E of the spindle E with or without a cushioning
sleeve of indiarubber or other elastic material or of wood; the outer rim of
this disc D is cut away to receive the four contact pieces G and to hold them
firmly circumferencially but with a comparative freedom to motion vertically.
The contact pieces G by means of the springs H are normally held away from
the faces of base A and of the contact terminals B. In order to produce electrical
connection between the pieces B & G, I form the underside of the cover C with
downwardly projecting surfaces J and in such positions that when the pieces G
are just about to come into line with the pieces B they shall be forced down on
to the said contacts B by reason of the incline or wedge action of the surfaces J.
I prefer to fit a second spring K to the pieces G to be either independent or
forming part of the first spring H so as to come between the pieces G and the
surfaces and to render unnecessary any refinement of fitting to ensure all con-
tacts being forced down together, this will be found of great use in connection
with such insulating material as porcelain. I may also provide further project-
ing surfaces on the cover C in such position that the springs K shall by the already
described wedging action bring to and hold at rest the disc D and its contacts (
at the "off" position. The quick break is effected by means of the spiral spring L
which engages at its inner end with the disc M which is fixed to the upper end
of the square sleeve E; the outer end of the spring L engages with the outer
circumference of the flanged sleeve N; this sleeve is also square at its upper
portion in order to engage with a key for operating the switch and in order to

page_text: give an initial tension to the spring LI fit a further small spring O to the cir-
cumference of the disc M so shaped as to engage in a recess in the raised por-
tion C¹ of the cover C and to require a comparatively strong pull of the spring L
to disengage it.
The contacts are connected in pairs by metal bridge pieces cast or otherwise
fixed to them or by a fuse P as shown. This fuse may be formed or provided
with any suitable damping device when used on circuits of high voltage. It will
now be seen that the switch is a double pole double break switch.
The working of the switch is as follows:-Assuming it to be as shown i.e. in
the onposition, the square sleeve N is rotated by a suitable key thus putting
into tension the spring until its force overcomes the spring O which is con-
sequently disengaged from the recess in C¹; the disc M sleeve E disc D) with its
contacts G are now free to rotate under the force of the spring L' and by the
construction already described the contacts G, almost before they have left contact
with pieces B will be released of pressure consequently the moving parts will be
freed of retarding action, except that due to their weight, and so will move quickly
to the "off" position and will be brought to rest by the spring O wedging against
the surface of the raised rim C. The close fitting of all the parts immediately sur-
rounding the contact pieces B & G at their surfaces of mutual contact effectually
prevents the formation of an arc. The better the fit or the more closely they
approximate surface to surface, the less need is there of a quick break.
addition of a quick break allows of the indifferent fit of such material as
porcelain.
The
Figures 3 & 4, Sheet 1 show in sectional elevation and plan another form of
my switch but with a straight or reciprocating motion corresponding to the
ordinary plug switch, and is also shown for double-pole double-break.
The relative parts being like lettered as in previous Figures 1 & 2 no further
description will be necessary to explain its action beyond that the pressure of the
pieces G upon B is produced by the spring K rising on the incline J and forcing
out the contacts G by lever action turning on the portion as a fulcrum. No
quick break is shown but should it be required it could be in the form of the
handle, being made seperate from, but connected to the body D through springs,
the springs being put in tension or compression by the necessary pressure on
the handle until the friction of contact and enertia of parts was overcome when
quick movement and quick break would be effected.
Figures 5 & 6 Sheet II show a lever type of switch in this case single-pole
double-break. The switch is shown at the on" position. The contact pieces G
are electrically connected together by the spring contacts or brushes K which
also forces the contacts G against the contacts B when in this position. To break
circuit the lever Q is pulled in the usual way, this puts under tension the
spring L until the stop 9 comes against the projection of the moveable insu-
lator when it is started and a quick break effected.
The body may be
A buffer is provided in the form of the spring R.
entirely removed or it may travel so far to leave the trailing portion interposing
between the two terminal contacts B. The quick break in this as in the previous
described switches being freed from retardation due to friction by the action of
the spring brushes K which cease to press on the pieces G almost before they
have left contact with the pieces 1.
The application of my invention to a controller for motors for traction or
like uses is shown by Figure 7 Sheet II where G represents the contacts as
hitherto in use; there may be any desired number of these and they may be
mounted on but insulated from one spindle as usual. The insulator D and con-
tact G when built up presents the appearance of a cylinder with various metal
faces here and there flush with the general surface of the cylinder, rotation being
effected, in the same manner as usual with the controllers. I prefer that the
fixed pieces A should fit very closely to the cylinder and they may be kept press-
ing lightly against it by springs suitably placed if desired. The contact terminals

page_text: correspond to those at present in use but have longer contact pieces B¹ so as to
admit of the interposition of the block or blocks A the contact piece B¹ passing
through suitable holes provided in the same block or blocks A. The spring
portion of B instead of, as in the controllers at present in use forcing the con-
tacts B on to the cylinder contacts G, are made, in my invention, to hold off
the contacts B, the latter being forced into contact with G by the action of the
cam S lever T and spring fingers V, the latter being insulated where they come
into contact with B. As shown, the cam S will have forced down the lever T
and so pressure would be exerted upon the back of pieces B.
It will readily be seen that this pressure is almost at once removed when the
cylinder is rotated from contact to contact in whichever direction it is moved.
The close fitting of the block A with contact B and cylindrical surface D with
contacts G and the release of frictional contact at the moment of breaking, will
effectually ensure sparkless breaking of the circuit.
It may be desirable in certain forms of circuit breaking apparatus to allow
freedom of fit between the insulating material immediately about the contact
faces; in this case in order to prevent the are following the moveable contact,
this latter with its insulating material can close in between suitably placed faces
of the insulating material, it will, under these conditions be necessary to prolong
the insulating material on the trailing edge or face of the moveable contact so
as still to intervene between the contacts between which the circuit has been
broken.
It will be obvious that it is not necessary in carrying out this invention that the
insulating material which follows the metallic contact pieces shall be rigidly
attached to the said contact pieces but it may be separately mounted so as to follow
the metallic contacts until it shall have effectively covered the contact terminals
when its further travel may be arrested. Also when so mounted it may be retained
for a certain portion of the travel of the metal contact, when it may be released
and fly over or between the fixed terminal contacts and in this way prevent the
formation of an arc.
The illustrations on the accompanying sheets of drawings will enable my
invention to be readily applied to circuit breakers having automatic release and
to almost any form of apparatus required to break electrical circuits where it is
desired to interrupt or break the electrical circuit without injurious sparking.
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
In circuit breaking apparatus for electrical circuits the application of any suit-
able material about the make and break contact faces closely approximating to one
another so as to leave no room or space to permit of the formation or continuance
of an arc when the circuit is broken, substantially as hereinbefore described and
in relation to Figs. 1 to 7 on the drawings herewith..
Dated this 21st day of October 1800