Note: Descriptions are shown in the official language in which they were submitted.
The present invention relates to electron
mechanical devices which comprise a fuse cartridge
and which are used as switches or circuit breakers.
Such an apparatus comprises, in principle, fixed
contacts, one or more corresponding mobile contacts,
a coil adapted to control displacement of the latter
and a fuse cartridge of relatively small caliber,
mounted in parallel on the system of contacts. When
the coil is energized, it repels by the Thomson effect
lo conductor plate fast with the mobile contacts,
which are then retained in the position of opening
by engagement of a comb, paw or the like. The circuit
constituted by the fixed and mobile contacts is thus
cut at a low voltage and all the current passes through
15 the cartridge which melts with a delay which is very
short but which is sufficient for the contacts to
be separated at least for the major part. The break
arc is thus established inside the cartridge where
it is absorbed by the filling material thereof.
As is known, it has been proposed to mount
the mobile contacts on an insulating plate shaped
so as to be inserted between the fixed contacts in
order to avoid any direct starting of electric arcs
there between This insulating plate is fast with
a disc-shaped plate which cooperates with an actuation
coil so as to be suddenly driven out by the Thomson
effect when said coil is energized. U.S. Patent No.
3 128 361 to KESSEKRING clearly illustrates such
an arrangement.
However, experience has shown that it is
difficult effectively to avoid bounce of the mobile
insulating plate under the effect of the holding
springs which are manually associated therewith,
and it is a principal object of the present invention
~LZ35~
to overcome this drawback.
According to the invention, the insulating
contact-holder plate is repelled by the disc-shaped plate
without being connected thereto, whilst the stroke of said
disc is stopped by a fixed stop which allows the plate to
pursue its movement by the effect of kinetic energy until it
is retained in the position of opening of the mobile contacts
by a catch bolt system.
Specifically, the invention relates to an electron
mechanical circuit breaker having improved structure, the breaker being of the type having opposed fixed contacts spaced
apart across a gap and having an insulating plate guided in a
housing for reciprocation within the gap, the plate being
spring-urged from an open position to a closed position and
the plate carrying mobile contacts which in the closed
position connect the fixed contacts together and which in the
open position are spaced therefrom, and the breaker having a
conductive disc in the housing disposed normal to the plate
and having a coil in the housing disposed adjacent to the
conductive disc on the opposite side thereof from the
insulating plate and operative when the coil is energized to
repel the conductive disc against the plate and drive it from
its closed position toward a fully open position, and the
breaker having a fuse cartridge connected in shunt with the
fixed contacts and operative to melt after a brief delay when
the contacts are driven open, the improvements comprising:
(a) a latch bolt supported in the housing and spring-urged
toward the insulating plate, and the plate having a latching
notch therein disposed to lie opposite the latch bolt when the
plate is in fully open position; and (b) the housing retaining
the conductive disc between the coil and the insulating plate
and normal to the plate and having a shoulder disposed to stop
motion of the disc after it has driven the plate partway
toward its fully open position, the kinetic energy of the
insulating plate carrying it the rest of the way to latch with
the bolt in fully open position.
oh/
~23S~
The invention will be more readily understood on
reading the following description with reference to the
accompanying drawings, in which:
Fig. 1 is a vertical section through an apparatus
according to the invention, the mobile contacts being closed.
Fig. 2 is a plan view, with part section and parts
torn away, along II-II (Fig. 1).
Fig. 3 is a part section along III-III (Fig. 1).
Fig. 4 partly reproduces Fig. 1, but showing the
parts in the position of opening of the contacts.
Referring now to the drawings, the fuse comprises
two fixed contacts constituted by the opposite ends of two
bars 1 disposed coccal with a small separating gap
lengthwise. Bolts 2 fix these bars to an upturned upper
insulating dish 3. Against the bottom thereof is disposed a
flat circular coil 4 which bears against the ribs pa of said
bottom. Between the coil 4 and the bars 1 is maintained an
intermediate piece 5, of generally cylindrical shape, provided
with a horizontal partition pa, as will be seen hereinafter.
Of course, the coil 4 is suitably coated with insulating
material so as to constitute a rigid piece.
- pa -
kh/lcm
I,'
lZ35i~
--3--
Immediately below this coil 1 is disposed
a circular mobile disc 6 made of a metal which is
a very good conductor and relatively light, such
as aluminum. The disc 6 is urged downwardly by a
5 spring 7 which abuts against the bottom of the dish
3, coccal to the coil 4, but it is retained against
the action of this spring by the upper edge of a
vertical insulating plate 8 which, passing through
the partition pa, passes between the fixed contacts
10 1 and abuts against a series of mobile contacts 9
which springs 10 maintain applied against said fixed
contacts 1. The lower edge of the plate 8 is provided
with a series of notches in which the mobile contacts
9 are engaged and whereby this part of plate 8 somewhat
15 takes the form of a comb. Each contact 9 is itself
provided with a notch pa in which is engaged a tooth
bottom of this profile, with the result that the
contact 9 in question is retained with respect to
the plate 8 longitudinally and transversely. On the
20 other hand, there are provided for each contact 9
two springs 10 located on either side of the mean
plane of the plate 8, these springs being engaged
on centering lugs 11 fast with the bottom aye of a
lower box Wyeth rectangular profile in plan, of
25 which the edges 12b, bent horizontally, are fixed
to the contacts or bars 1 by bolts 13.
The reaction of the springs 10 is sufficient
to maintain the disc 6 applied with a slight clearance
beneath coil 4, despite the presence of the spring
30 7, the mobile contacts 9 bearing against the fixed
contacts 1 with the desired pressure, notwithstanding
the inevitable manufacturing and assembly tolerances.
When the coil 4 has a sufficiently intense
current pulse passing there through, the disc 6 is
Lo
--4--
repelled downwardly by the Thomson effect against
springs 10. It lowers until it abuts against an inner
edge 5b of piece 5, whilst plate 8 continues its
descending stroke under the effect of the kinetic
energy, moving the mobile contacts 9 away from the
fixed contacts 1, to engage in lowered position under
the effect of a bolt 14, repelled by a spring 15,
the end of this bolt engaging in a notch pa in the
plate.
Plate 8 is guided in its descending movement
on the one hand by partition pa that it passes through
with reduced clearance, on the other hand by vertical
ribs aye provided inside the box 12 (cf. Figs. 2
and 3). As for bolt 14, it rests on a lowered part
15 5c of the partition pa (cf. Fig. 3) and may move
beneath two edges Ed thereof. It comprises on its
lower face a notch aye of which the flat bottom bears
on a rod 16.
Rod 17 extends parallel to the largest
20 horizontal dimension of the lower box 12 up to the
vicinity of the wall of the upper dish 3 and is connect
ted by welding to a control lever 17 mounted to rotate
on a pin 18, the lower end of this lever projecting
beneath the pin and terminating in a maneuvering
25 knob 19.
Pin 18 is driven in a lateral boss in the
lower box 12 which is suitably notched to allow passage
of the lever 17 as well as the slight angular clearance
necessary for operation (Figs. 2 and 3).
Starting from the position of Fig. 1 and
assuming that coil 4 receives the sudden driving
current pulse, the plate 8 is driven downwardly,
lowering the mobile contacts 9 and it is engaged
on the bolt 14 by its notch pa (position shown in
~Z35~6
--5--
Fig. 4). When it is desired to close the circuit
again, it suffices to maneuver the knob 19 in the
desired direction to displace rod 16 towards the
right in Fig. 1. This rod repels bolt 14 against
5 spring 15 and thus disengages plate 8 which rises
under the effect of springs I
In each bar or fixed contact 1 is screwed
a vertical rod 10 which extends downwardly through
a distance tube 21, its lower end receiving a nut
I 22 which makes it possible to tighten against the
distance tube 21 one, 23, of the two flat blades
of a fuse cartridge 24, which is thus in shunt on
the system of mobile contacts 9. As shown, rods 20
and distance tubes 21 are long enough for the cartridge
15 to be easily housed beneath the lower box 12.
Finally, an insulating lower cover 25 is
provided, adapted to close the cartridge. This cover,
made of insulating material, is articulated on the
edge of the box 12 via a pin 26. Its end opposite
20 this pin comprises an edge aye which is engaged in
an appropriate retaining piece very schematically
indicated in chain-dotted lines at 27.
The fuse which has just been described
is totally enclosed and there is therefore no danger.
25 However, it remains perfectly accessible, particularly
for changing the cartridge after cut-off. Thanks
to the insulating plate 8 which is inserted between
the fixed contacts 1 at the instant of opening, any
risk of direct starting of arcs between the latter
30 is eliminated and furthermore these contacts 1 may
be extremely close to one another, this reducing
the dimensions and earth of the mobile contacts 9,
thus accelerating operation.
It will further be noted that, by reason
I
I
of the edge or stop shoulder 5b, the kinetic energy
of the mobile disc 6 is absorbed by the shock against
the shoulder in question, which may be very broadly
dimensioned, this dispensing with having to provide
S buffers, dampers or the like to limit the stroke
of the mobile contacts 9, the springs 10 proving,
in practice, to be largely sufficient to this end.
Tests have shown that this arrangement avoided any
operational defect of the apparatus under the effect
10 of an untimely bounce of the mobile contact-holder
plate.
