Improvements in Automatic Break or Interrupter Apparatus for Electric Currents.
Year: 1898

page_text: Date of Application, 12th July, 1898-Accepted. 10th Sept., 1898
COMPLETE SPECIFICATION.
Improvements in Automatic Break or Interrupter Apparatus for
Electric Currents.
I, THOMAS BURTON KINRAIDE, of 38, Spring Park Avenue, Jamaica Plain, in the
State of Massachusetts, one of the United States of America, Electrician, 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:—
It is the object of my invention to provide an improved automatic break or inter-
rupter for electric currents, my invention being particularly adapted for use in inter-
rupting the primary current of induction coils in connection with X-ray and kindred
apparatus.
My invention secures high speed and accuracy of break, the successive breaks
being rendered similar and synchronous, provides uniformity of wear of the make-
and-break contacts, cures the irregularity and unsteadiness of the current hitherto so
objectionable, increases the frequency, and gives uniform action of both current and
apparatus under different resistances, besides simplifying and prolonging the life of
the instrument.
As heretofore constructed, these instruments have had a break hammer carried
on the free end of an ordinary leaf-spring vibrating between the core-end of an
electro-magnet and a small contact or anvil, the latter being mounted
the end of an adjusting screw in the free end of a post or
on
standard.
One serious drawback to these instruments has been that the speed of interruption,
i.e., the speed of the vibrations of the hammer, has been quite limited and there
has been an unevenness of break.
I have found that these faults are due to a compound vibration of the instrument
which tends to hasten some of the breaks and to retard others, and I have further
found that this compound vibration, as I call it, may be obviated and that high speed
may be attained and accurate breaks secured by providing an absolutely rigid and
unyielding post or standard; as a result of this feature of my invention, the objec-
tionable inaccuracy and unevenness of the breaks or interruptions dissappear, and a
nicety of adjustment and compensation is feasible which would not otherwise be
possible.
A further objection to the present old style of instrument, above mentioned, is
that as the tension of the spring vibrator is increased to vary the electrical resistance
of the break, the sparking of the instrument is increased, the current being also
otherwise rendered irregular and uncertain, and I have discovered that this is due to
the fact that in the adjustment of the vibrator the hammer is thrown more or less
out of alignment with the core-end and anvil,
It is therefore one chief feature of my invention to provide means to maintain
the hammer in proper accurate alignment with its core and anvil.
Again, irregularity and unsteadiness of current are due to the uneven wear of the
contacting surfaces of the hammer and anvil, the intense heat of the constant arcing
serving to fuse and batter down the said surfaces unevenly; and therefore I have

page_text: mounted one of these surfaces on a rotatable spindle, so that the irregularities thereof
may be automatically removed or obviated by rotating it as the hammer is
vibrated.
In order still further to increase the efficiency of the break, I make the several
parts thereof laminated, so as to get rid of the heating effects, thereby permitting
the break to be extremely rapid.
In this connection also I provide a collector for the lines of force, thereby enabling
a smaller hammer to be used with the effect of a large one.
Other advantages and features of improvement will be pointed out in the course of
the following description of the details of construction.
In the drawings I have omitted all unnecessary details, confining the drawings to
the details of improvement, and it will be understood that the latter may be used in
connection with any suitable or preferred general style of apparatus.
Fig. 1 is an end elevation, partly broken away, showing one embodiment of my
invention.
Fig. 2 is a top plan view thereof.
Fig. 3 is a broken detail in side elevation, showing a slight modification.
Fig. 4 is a side elevation of the collector, a portion of the hammer being shown in
operative position.
Fig. 5 shows a detail of a modified collector.
Fig. 6 is a fragmentary detail in top plan, showing a rigid collector placed on the
side of the hammer opposite the coil.
Fig. 7 illustrates one of the objectionable features of the old style instrument.
On a suitable base A is mounted a coil B supported by end supports c, c¹, herein
shown as receiving the core b at its ends.
The hammer D, carried by a vibrator E, reciprocates between the core end 6¹ and
an anvil G, the hammer having a reduced end e held rigidly on the vibrator by a
nut e¹.
Heretofore this vibrator has been a leaf-spring h, as indicated in Fig. 7, this spring
being deflected more or less to the right when it has been desired to increase the
electrical resistance offered by the hammer, the result being as shown in exaggerated
form in Fig. 7, where it appears that the spring h when deflected to its dotted
position inevitably upsets the hammer, so that the latter, when attracted to the
core 6¹, strikes the latter with its upper edge d² only, thereby increasing the resis-
tance entirely out of proportion to that intended, and tending to burn or fuse the
small point of contact d², also leaving a spark gap ds, tending to ruin the hammer;
the disastrous effects at the opposite end of the hammer being of the same sort
excepting that the contact surfaces being smaller and composed of platinum, said
effects are still more serious.
Accordingly, I obviate these disastrous results by making the vibrator E rigid and
unyielding for most of its length, as shown at e², a short resilient section e³ being
preferably provided at its lower end next to the stud a, to which it is shown as
fastened, and the necessary tension being secured by means of an auxiliary or tension
spring K on the shank of an adjusting screw k, working at its threaded end in a
post a and journaled at ¹ in a standard a².
An adjustable thumb nut k² receives one end of the spring K, the opposite
end bearing against the vibrator E which rides loosely over the screw rod k.
In this preferred form of mechanism for accomplishing my object, turning the
screw k to the right or left correspondingly relaxes or tightens the spring K, thereby
tending to move the vibrator E bodily forward to a greater or less extent to increase
the number of amperes or quantity of current transmitted, and it will be noted that
the hammer does not depend on the vibrator for its tension or resistance, but rather
on the independent spring K, which bears centrally forward against the vibrator, the
yielding section e flexing readily, enough to permit the required movement forward
of the rigid portion e².
I prefer to place the hammer at one side of the core, directly in the field of the
greatest number of lines of force, the direction of the latter being indicated by

page_text: arrows in Fig. 2, whereby the action of the apparatus is very materially improved;
and in order still further to increase the frequency, and to get rid of the heating
thereof, so that the brake can be extremely rapid, I make the several parts thereof
laminated, as clearly shown, the core being preferably composed of a plurality of wires,
and the hammer of a number of plates secured together, although any other means
of lamination is within my invention.
In connection with the improved hammer, I provide means for positively limiting
its movement, said means being herein shown as a projection or engaging lug e* on
the vibrator cooperating with a stop e preferably adjustable.
By reason of this construction the length of the spark gap between the hammer D
and its anvil G is positively controlled, so that the time period of the interruptions
may be regulated to the requirements of the circuit, for discharging the condenser at
the proper moment to accelerate the inductive action of the primary of the induction
coil with which we will suppose the apparatus is being used.
Adjacent the hammer and preferably above it I provide a collector L for the lines of
force, to direct them upon the hammer, whereby a much smaller hammer may be used
than would otherwise be possible for the same effect.
&
In Figs. 1, 2 and 4, this collector is shown as composed of a body of metal L, pre-
ferably soft steel or iron and laminated, placed within the field of force of the coil
and immediately adjacent the hammer, thereby presenting to the hammer
field of strong magnetic intensity, so that it is equivalent to making the hammer
much larger, at the same time permitting a much smaller moving part than
usual.
Preferably this collector is movable relatively to the hammer, so that its effect on
the latter may be varied, as indicated in Figs. 1-5, where the collector is shown
as pivotted at and as having its lower end convexly curved (Fig. 5) adjacent the
hammer D, or internally formed to endorse said hammer (Figs. 1, 4).
By means of the collector the amount of current delivered through the break is
readily controlled, inasmuch as the collector tends to gather in the lines of force and
direct them to the hammer; so that if the collector is in the full line position, Figs. 1
and 5, the greatest intensity will result, whereas if the collector is in its dotted line
position, a less intensity will result, and this may be varied according to the position
into which the collector is swung, the resultant effect upon the hammer being that it
has an active or sluggish movement according to the position of the collector.
When the collector is swung entirely away from the hammer or in case it is
omitted entirely, the tendency of the hammer is to lag or hang to the anvil as it is
drawn away, whereas with the collector in its full line position, as shown, the action of
the break is short and quick.
The collector is shown as laminated, Fig. 5, showing it applied to a break having
its hammer at the end of the core, while the other figs. show the collector applied to
the special form of hammer forming part of my new break.
The configuration and position of the collector may be changed to include a greater
or fewer number of the lines of force, or into the entire field, according to the effect it
is desired to produce upon the hammer, one example being illustrated in Fig. 6 in which
the collector L' is shown as mounted at the side of the hammer opposite the
coil.
With this construction, whenever, by the tearing off of small pieces of the metal
from the contact points, the break gap is partially short circuited when open, the
rapidly increasing lines of force are so concentrated by the collector upon the hammer
as to drag the latter sideways, toward the collector, thus overcoming the short circuit
by shearing apart the fused particles and separating the points, the hammer then
resuming its normal vibration.
It will be understood that as the hammer end e is pulled away from the anvil G, an
arc is formed which inevitably fuses a slight portion of the opposing surfaces, and,
as the breaks are rapid these surfaces, although platinum, are quickly rendered
uneven..

page_text: Accordingly, I provide means to relatively rotate the meeting surfaces of the anvil
and hammer, independently of the rotations due to the adjustments of said parts, the
said means being herein shown as preferably consisting of a freely rotatable spindle g
centrally mounted in a hollow adjusting screw gl having threaded engagement with
an extended bearing a³ in the standard at, being fixed in its adjustments by a check
nut g².
The spindle g is rotated by a thumb wheel g³ pinned on its outer end, and is held
against longitudinal movement by a collar g' fixed near its inner end to abut against
the inner end of the screw carrier g¹.
The spindle is threaded at g5 to receive the anvil & the latter being shown in the
form of a threaded cap provided with a required platinum contact, the platinum being
soldered thereon, as indicated in heavy section lines Fig. 1.
The collar gand anvil are made of a size to permit them to be withdrawn
together, with the adjusting screw g¹, as the latter is screwed out of the standard at.
It is understood that as the platinum points wear and fuse away the anvil is nicely
adjusted forward by its screw carrier gl to compensate therefor.
Under the old construction the surfaces would fuse and wear unevenly, as explained,
and then when it became necessary to adjust the anvil forward, it would be impossible
because it would be found that the surfaces had become more or less interlocked,
thereby preventing any relative rotation thereof, the result being that the apparatus
was rendered useless until the anvil had been removed and the contacting surfaces
carefully filed down, not only entailing loss of time but loss of the platinum.
According to my invention the adjusting movement is entirely independent of any
rotation of the anvil.
In order to give the most efficient work, the breaks should not only be exceedingly
rapid, but they should be even or accurate in synchronism.
Accordingly, I have rendered the standard, which supports the anvil, absolutely
rigid and non-vibrant, finding as a result that the accuracy of break which is sought
is thereby attained, and that the speed or note of vibration is raised, this being due
to the prevention of compound vibrations.
I prefer to render the standard thus rigid by interposing a bar or brace M,
Figs. 1 and 2, or M1, Fig. 3, of insulating material between opposite posts of the
frame, this bar being let into the frame and held rigid by said screws, the object
being to prevent the standard, and hence the anvil, from being responsive to the
vibrations of the hammer, and thereby occasioning a compound or confused vibration
or interruption of the current.
Various modifications and details of mechanisms may be used to embody my
invention.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
In an automatic break or interrupter for electric currents:-
1. A high speed break, comprising a coil and its core, an anvil in electric circuit
with said coil, a standard supporting the anvil, and means to render said standard
absolutely non-vibrant, whereby compound vibrations are prevented and the speed
is increased, substantially as described.
2. A high speed break, having a hammer vibrating between a core-end and an
anvil, means to vary the vibrating resistance of said hammer, and means to main-
tain said hammer in approximately unvarying end alignment with said core-end and
anvil, substantially as described.
3. A high speed break, a hammer, a vibrator supporting the same, and an adjust-
able tension device to vary the resistance of said hammer, said vibrator having an
extended rigid portion extending from said hammer, substantially as described.
4. A high speed break, a hammer, a vibrator supporting the same, and an adjust-
able tension device to vary the resistance of said hammer, said vibrator having an
extended rigid portion extending from said hammer and being provided at its

page_text: opposite end with means to permit said rigid portion to be deflected slightly, sub-
stantially as described.
5. An electric break, having a hammer vibrating against an anvil, and means to
adjust the latter, means to rotate said anvil independently of its said adjustment,.
snbstantially as described.
6. An electric break, the combination with a hammer, its anvil, and a hollow
adjusting screw for the latter, of a spindle carrying said anvil and rotatably mounted
therein, substantially as described.
7. The herein described anvil, the same consisting of an interiorly threaded cap,
and a centrally extended platinum contact integrally secured thereon, substantially
as described.
8. The combination with an electric break having an electro magnet, an anvil, and
a vibrating hammer, of a collector to concentrate the lines of magnetic influence on
said hammer, substantially as described.
9. The combination with an electric break having an electro-magnet, an anvil,
and a vibrating hammer, of a collector to concentrate the lines of magnetic influence
on said hammer, and means to vary the position of said collector relatively to said
hammer, substantially as described.
10. The combination with an electric break, having an electro magnet, an anvil,
and a vibrating hammer, of means to shear or drag sideways the hammer from the
anvil whenever the break-gap between the hammer and anvil is partially short cir-
cuited by the fusing or clinging of the metal at the contact points, substantially as
described.
11., An electric break of the vibrator class, provided with a hammer composed of
laminated material, substantially as described.
12. An electric break, a core, a hammer, and collector, to concentrate the lines of
magnetic influence on the hammer, said collector being composed of laminated
material, substantially as described.
13. The combination with an electric break, having an anvil and a vibrating
hammer, of a positive stop to limit and positively stop the movement of the latter
from the anvil, substantially as described.
Dated the 9th day of July 1898
WM. BROOKES & SON,
55 & 56. Chancery Lane, London,
Agents for the Applicant.