Title of Invention	MAGNETIC SUB-ASSEMBLY FOR ELECTRICAL EQUIPMENT OF CIRCUIT-BREAKER TYPE
Abstract	The present invention discloses magnetic subassembly for an electrical device of the circuit- breaker type, made up of an inductor coil associated with a magnetic yoke (8, 8') and with a core (6)/mobile striker (5)/mobile assembly in translation against a torsion spring (1) with a coiled central portion (2) and two extremity arms (3, 3') spread out in a V-shape pushing against stops (7, 7'), the spring (1) and said stops (7, 7') being driven by a relative movement such that the distance between the stops (7, 7') and the central portion (2) of the spring (1) in the direction of the translation increases during closing of the air gap (9) positioned between the core (6) and the yoke (8, 8').

Title of Invention

MAGNETIC SUB-ASSEMBLY FOR ELECTRICAL EQUIPMENT OF CIRCUIT-BREAKER TYPE

Abstract

The present invention discloses magnetic subassembly for an electrical device of the circuit- breaker type, made up of an inductor coil associated with a magnetic yoke (8, 8') and with a core (6)/mobile striker (5)/mobile assembly in translation against a torsion spring (1) with a coiled central portion (2) and two extremity arms (3, 3') spread out in a V-shape pushing against stops (7, 7'), the spring (1) and said stops (7, 7') being driven by a relative movement such that the distance between the stops (7, 7') and the central portion (2) of the spring (1) in the direction of the translation increases during closing of the air gap (9) positioned between the core (6) and the yoke (8, 8').

Full Text	The present invention concerns a magnetic sub-assembly for an electrical device of the circuit-breaker type, traditionally made up of an inductor coil associated with a magnetic yoke and a mobile magnet core in translation against a spring, said core pulling with it a striker intended to trigger a mechanical lock controlling the position of the mobile contact in relation to the fixed contact. The function of the magnetic subassemblies or triggering devices is to separate the respective mobile and fixed contacts in case of short circuit in the circuit in which they are connected. The brutal excess current running through the coil saturates the magnetic circuit, causing the movement of the mobile core, which fills the air gap separating it from the rest of the magnetic yoke. A return spring is interposed between an element fixed in relation to the housing of the device and the mobile core, so that this mobile core returns to its resting position (reestablishing the air gap) when the circuit is cut. The rigidity of the spring is chosen according to the category to which the circuit-breaker belongs, shown in particular by the existence of "sensitivity" curves B, C and D which define the interval, expressed according to the nominal intensity of the circuit-breaker, in which this must trigger. This rigidity obviously also depends on the capacity of the circuit-breaker. For a high-capacity circuit-breaker, for example 125 amperes, and which depends on curve D according to which there must not be a magnetic trigger, for example, for a current value below 10 ln = 1250 amperes according to the IEC 60-898 standard, the spring chosen is obviously equipped with a rigidity enabling it to oppose the magnetic force generated by the currents of this strength in the coil. The problem is that this type of spring, which necessarily has a correlatively high rigidity, obviously presents a response time as much greater as said rigidity is significant. This is the case in particular in traditional magnetic subassembly configurations with a solenoidal coil surrounding the mobile core, in which the springs used are coil compression springs, for which the energy to overcome increases during movement of the mobile core. In order to avoid welding of contacts and to limit the short-circuit currents as much as possible, the magnetic subassemblies must necessarily close their gap as quickly as possible. It must be noted that the increase in response time which results from the rigidity and the nature of the springs used, in particular for strong-capacity circuit-breakers and the sensitivity of which corresponds to curve D, does not go in this direction. The objective of the present invention is consequently to propose a configuration such that the resistive energy opposed by the spring decreases during movement of the mobile assembly made up of the core and its striker during a short circuit. To this end, principally, the magnet subassembly of the invention is characterized in that said spring is a torsion spring with a coiled central portion and two terminal arms being spread out in a V-shape pushing against stops, the spring and said stops being driven by a relative movement such that the distance between the stops and the central portion of the spring in the direction of translation increases during closing of the gap located between the core and the yoke. The angle formed by the extremity arms in relation to the axis of movement is modified during the movement. The result of the forces exercised on the spring at the level of the stops consequently changes in angle, as we will see in more detail below, and the projection of these results on the axis of movement decreases in intensity as the central portion of the spring and said stops move away from one another. From then on, the energy necessary to hinder the resistive force of the spring decreases as the core/striker assembly approaches the mechanical triggering lock. Preferably, the torsion, spring is symmetrical in relation to the axis of movement of the mobile assembly. Such a symmetry can be explained by the translational movement according to this axis, optimal operation of which is favored by a configurational balance in relation to said axis. In the invention, the mobile assembly moves by sliding and is guided in at least one slide channel fixed in relation to the housing. The spring acts on the mobile assembly which may disturb the direction of movement, and consequently the path of the striker, if guiding was solely the result of the effect of magnetic forces on the core's movement. More precisely, the mobile assembly is made up of an overlaid magnetic plate and striker. These two elements exercise distinct functions, the magnetic plate or core necessarily being made of a magnetic material which is not necessarily the best adapted for the striker, for economical or mechanical reasons depending on the tasks entrusted to it. According to the invention, the sliding of the magnetic plate/striker mobile assembly is done by guiding said assembly in the slide channels symmetrically arranged in the side cheeks located in the housing, fixed, on either side of the magnetic subassembly. The guiding function is therefore performed in this case by pieces forming said cheeks, which may be made of a synthetic material, molded, for example, to which it is easy and inexpensive to give a complex shape for the performance of various functions. As will be shown in more detail below, said cheeks also have in particular the function of housing the magnetic subassembly. More precisely, each slide channel may be made up of a wall parallel to the axis of movement of said mobile assembly, on either side of which respectively cheeks slide, these cheeks laterally exceeding the striker and one face of the magnetic plate facing said cheeks. The two components of the mobile assembly therefore participate in the translational guiding. The magnetic subassembly of the invention, beyond such a coil, preferably comprises a trapezoidal magnetic plate cooperating with an air gap in the yoke, also trapezoidally shaped. According to one possible configuration, the spring stops are made up of cheeks each having a C-shaped housing section at one part of an extremity arm of the spring, said C-shaped section being stretched perpendicularly in relation to the direction of movement of the mobile assembly. These stops make it possible to position the spring while exercising prestressing. In a first version of the invention, the coiled portion of the spring is pulled by the mobile assembly, and the spring stops are fixed in relation to the housing of the device. In this case, preferably, the central portion of the spring is wound around the head of a hub making up a protrusion of the striker crossing and exceeding an opening located in the magnetic plate, a portion of said striker equipped with an impact surface situated perpendicularly to the movement and standing up in front of the frontal edge of said plate. In this hypothesis, the mechanical relationships, both with the spring and with the mechanical lock performing the triggering, are taken care of by the striker. The sole function of the magnetic plate is to pull said striker when said plate is subjected to Laplace forces sufficient to successfully oppose the resistive force of the spring. Alternatively, the spring may be fixed to the housing of the device, and the spring stops are attached to the mobile assembly. The configuration of the magnetic subassembly of the invention is based on that which is in particular explained in detail in patent application EP-0 23 601 76.8 of the applicant, the content of which is incorporated by reference in the present description. The invention will now be described in more detail, with reference to the figures presented in the accompanying drawings, for which: - figure 1 is a schematic illustration of the configuration of the invention, with a diagram of the forces present at the level of the stops ; - figure 2 shows a perspective view of the mobile assembly with a torsion spring; - figure 3 shows the whole of the preceding figure with the rest of the magnetic yoke; - figure 4 is a top view of the striker cooperating with a torsion spring ; - figure 5 shows the cooperation of the mobile assembly with a lateral cheek attached to the housing of the electrical device ; - figure 6 is a top view of the configuration appearing in the preceding figure, with the two side cheeks and without the magnetic plate; - figure 7 is a bottom view ; - figure 8 shows the piece on which one prefits the spring; and - figure 9 shows said prefitting piece fixed to the side cheeks. The appended figures 2 to 9 show a version of the invention in which the torsion spring forms one piece with the mobile equipment. In reference to figures 1 and 2, the torsion spring (1) comprises a central coiled portion (2) and extremity arms spread out in a V-shape (3) and (3'). This spring (1) is pulled by the hub (4) of a mobile assembly comprising on one hand the striker (5) and on the other hand the core / magnetic plate (6). The resistance opposed by the spring (1) to the movement of the mobile assembly, 5and in particular of the hub (4) on the axis x may be calculated as follows: The spring (1) exercises a force on the stop (7). The force seen by the stop is in accordance with the diagram. is in fact the reaction of the stop (7) on the arm (3) of the spring (1), taking friction into account. It is therefore separated from an angle cp of the reaction of the stop (7) on the arm (3) of the spring (1), in the absence of friction. From which: However, the resistant torque opposed by the spring is expressed by the relationship: C = kα a being the angular variation of the angle existing between the direction of movement x and the line joining the stop (7) to the center of the hub (4) and k, the rigidity of the spring (1). The value of the torque may also be written: By replacing with its value with the help of , one obtains: From which: The component of this resistive force on the axis of movements x is then equal to: This formula relates to only one stop (7). Given the symmetry with the stop (7'), the total resistive force exercised by the spring (1) is in reality: When a movement begins, the angular movement a increases and the part of this formula due to the spring torque, namely ka / R, increases as well. The coefficient 1/cos0 also increases slightly, because the cos 9 decreases a little. The coefficient Fr is stable, since friction is considered constant. On the other hand, the variable sin T, which constitutes the projection on the axis decreases. There is a geometric configuration such that the increases due to a and 8 do not compensate for the decrease resulting from sin T. In this configuration, the resistive energy seen by the plate is minimized in relation to a traditional system. In reference to figure 3, the mobile plate (6) associated with the striker (5) and the spring (1) is shown in the broadened context of its association with the magnetic yoke, said yoke being made up of two symmetrical parts (8, 8'). This yoke comprises a first air gap (9) in which the plate (6) moves, and a second air gap (10) intended to receive the mobile contact (not shown). Figure 4 shows, in more detail, the striker (5) which is present in the form of a sliding carriage equipped with a central hub (4), cheeks (11, 11') intended to slide in sliding channels (see below), said chariot having, in front in the direction of movement in case of short circuit, a projection equipped with a flat frontal impact surface (12). Figure 5 shows the mobile equipment made up of the plate (6), the striker (5) and the spring (1) placed in position, meaning situated in relation to other elements either of the magnetic subassembly, or intended for its immobilization in the housing. Thus, said mobile equipment is above the coil (13) of said magnetic subassembly, which in fact forms three-quarters of the loop made by a magnetic plate folded around a core (14) traditionally made up of stacked plates. The coil (13) / core (14) assembly is inserted in a side cheek (15) which participates in the positioning of a certain number of elements of the circuit- breaker. In principle, the coil (13) and the core (14) are masked by one of the parts (8') of the yoke, which is not shown here. There is also a second cheek symmetrical to the first, which makes it possible to complete the lodging of the magnetic subassembly and which is also not shown in figure 5 so as not to hinder the readability of the figure. This second cheek (15') is, however, shown in figure 6, in which the quasi-entirety of the magnetic subassembly, with the exception of the spring (1) and the upper parts of the mobile equipment, namely the hub (4) and the forward projection with its impact surface (12), is masked. In fact, when the two legs (15) and (15') are assembled, their upper part makes up a window (16) enabling the movement of the mobile equipment, and contributing at least partially to its guiding in the direction of the arrow (F). This guiding is done, as appears in figures 5 to 7, by flat parallel walls (17, 17') located under the upper part of the legs (15, 15') with which the lateral cheeks (11, 11') of the mobile striker (5) may cooperate during sliding. One wall of the magnetic plate (6) facing said cheeks (11, 11') slides on the other side of each wall (17, 17'), which may moreover be equipped with positioning guides (19,19'). The spring (1), the ends (3, 3') of which appear, is topped by a sort of cover or hood (18) which is mounted on the upper parts of the legs (15, 15'). This cover (18), which enables pre-assembly of the spring (1), appears in figure 8. It contains the stops (7, T) which determine in particular the prestressing of the torsion spring (1), and thereby make it possible to adapt it to the capacity and sensitivity of the circuit-breaker. The stops (7, 7') contain a C-shaped lodging for the ends (3, 3') of the spring (1). When the cover or cap (18) is mounted, by embedment, on the two legs (15, 15'), as appears in figure 9, the upper part of the mobile assembly is not completely covered in order to preserve the function of the flat impact wall (12) of the striker (5). This wall must indeed be able to come into contact with the magnetic triggering lock, of which at least one portion is inserted between the two legs (15, 15') so that contact may be realized. We Claim : 1. Magnetic subassembly for electrical equipment of the circuit-breaker type, made up of an inductive coil associated with a magnetic yoke (8, 8') and with a moving core (6)/ striker (5)/assembly that can move translatably against a spring (1), characterized in that said spring is a torsion spring with a central coiled central portion (2) and two end arms (3, 3') opening out in a V-shape and bearing against stops (7, 7'), the spring (1) and said stops (7, 7') being moved relatively such that the distance between the stops (7, 7') and the central portion (2) of the spring (1) in the direction of the translation increases as the air gap (9) arranged between the core (6) and the yoke (8, 8') closes. 2. Magnetic subassembly as claimed in the preceding claim, wherein the torsion spring (1) exhibits a symmetry with respect to the axis of displacement of the moving assembly (5, 6). 3. Magnetic subassembly as claimed in one of the preceding claims, wherein the moving assembly (5, 6) moves by sliding and is guided in at least one runner that is fixed relative to the casing. 4. Magnetic subassembly as claimed in any one of the preceding claims, wherein the moving assembly (5, 6) is formed by a magnetic pallet (6) and by a striker (5) which are arranged one on the other. 5. Magnetic subassembly as claimed in the preceding claim, wherein the sliding of the moving magnetic pallet (6) /striker (5) assembly is achieved by guiding said assembly in runners made symmetrically in the side panels (15) secured in the casing on either side of the magnetic subassembly. 6. Magnetic subassembly as claimed in the preceding claim, wherein each runner is formed by a wall (17, 17') parallel to the axis of displacement of said moving assembly (5, 6), on either side of which slide respectively, tabs (11, 11') projecting laterally from the striker (5) and a face of the magnetic pallet (6) oriented to face said tabs (11, 11'). 7. Magnetic subassembly as claimed in any of claims 4 to 6, wherein the pallet (6) is of trapezoidal shape cooperating with an air gap (9) of the yoke (8, 8') also of trapezoidal shape. 8. Magnetic subassembly as claimed in any one of the preceding claims, wherein the stops (7, 7') for the spring are formed by tabs each providing a housing having a C-shaped cross-section at one part of an end arm (3, 3') of the spring (1), said C-shaped cross-section being understood to be perpendicular to the direction of displacement of the moving assembly (5, 6). 9. Magnetic subassembly as claimed in any one of the preceding claims, wherein the coiled portion (2) of the spring (1) is carried by the moving assembly (5, 6), and the stops (7, 7') for the spring (1) are fixed relative to the casing of the equipment. 10. Magnetic subassembly as claimed in the preceding claim, wherein the central portion (2) of the spring (1) is wound around the top part of a shaft (4) forming a protuberance from striker (5) passing through and projecting out of a hole made in the magnetic pallet (6), a portion of said striker (5) equipped with an impact surface (12) oriented perpendicularly to the displacement being arranged in front of the frontal edge of said pallet (6). 11. Magnetic subassembly as claimed in any one of claims 1 to 8, wherein the spring (1) is fixed to the casing of the equipment, and the stops (7, 7') for the spring (1) are secured to the moving assembly (5, 6). ABSTRACT MAGNETIC SUB-ASSEMBLY FOR ELECTRICAL EQUIPMENT OF CIRCUIT-BREAKER TYPE The present invention discloses magnetic subassembly for an electrical device of the circuit- breaker type, made up of an inductor coil associated with a magnetic yoke (8, 8') and with a core (6)/mobile striker (5)/mobile assembly in translation against a torsion spring (1) with a coiled central portion (2) and two extremity arms (3, 3') spread out in a V-shape pushing against stops (7, 7'), the spring (1) and said stops (7, 7') being driven by a relative movement such that the distance between the stops (7, 7') and the central portion (2) of the spring (1) in the direction of the translation increases during closing of the air gap (9) positioned between the core (6) and the yoke (8, 8').

Full Text

The present invention concerns a magnetic sub-assembly for an
electrical device of the circuit-breaker type, traditionally made up of an inductor
coil associated with a magnetic yoke and a mobile magnet core in translation
against a spring, said core pulling with it a striker intended to trigger a
mechanical lock controlling the position of the mobile contact in relation to the
fixed contact.
The function of the magnetic subassemblies or triggering devices is to
separate the respective mobile and fixed contacts in case of short circuit in the
circuit in which they are connected. The brutal excess current running through
the coil saturates the magnetic circuit, causing the movement of the mobile
core, which fills the air gap separating it from the rest of the magnetic yoke.
A return spring is interposed between an element fixed in relation to the
housing of the device and the mobile core, so that this mobile core returns to its
resting position (reestablishing the air gap) when the circuit is cut. The rigidity of
the spring is chosen according to the category to which the circuit-breaker
belongs, shown in particular by the existence of "sensitivity" curves B, C and D
which define the interval, expressed according to the nominal intensity of the
circuit-breaker, in which this must trigger. This rigidity obviously also depends on
the capacity of the circuit-breaker. For a high-capacity circuit-breaker, for
example 125 amperes, and which depends on curve D according to which there
must not be a magnetic trigger, for example, for a current value below 10 ln =
1250 amperes according to the IEC 60-898 standard, the spring chosen is
obviously equipped with a rigidity enabling it to oppose the magnetic force
generated by the currents of this strength in the coil. The problem is that this
type of spring, which necessarily has a correlatively high rigidity, obviously
presents a response time as much greater as said rigidity is significant.
This is the case in particular in traditional magnetic subassembly
configurations with a solenoidal coil surrounding the mobile core, in which the
springs used are coil compression springs, for which the energy to overcome
increases during movement of the mobile core.

In order to avoid welding of contacts and to limit the short-circuit currents
as much as possible, the magnetic subassemblies must necessarily close their
gap as quickly as possible. It must be noted that the increase in response time
which results from the rigidity and the nature of the springs used, in particular for
strong-capacity circuit-breakers and the sensitivity of which corresponds to
curve D, does not go in this direction.
The objective of the present invention is consequently to propose a
configuration such that the resistive energy opposed by the spring decreases
during movement of the mobile assembly made up of the core and its striker
during a short circuit.
To this end, principally, the magnet subassembly of the invention is
characterized in that said spring is a torsion spring with a coiled central portion
and two terminal arms being spread out in a V-shape pushing against stops, the
spring and said stops being driven by a relative movement such that the
distance between the stops and the central portion of the spring in the direction
of translation increases during closing of the gap located between the core and
the yoke.
The angle formed by the extremity arms in relation to the axis of
movement is modified during the movement. The result of the forces exercised
on the spring at the level of the stops consequently changes in angle, as we will
see in more detail below, and the projection of these results on the axis of
movement decreases in intensity as the central portion of the spring and said
stops move away from one another.
From then on, the energy necessary to hinder the resistive force of the
spring decreases as the core/striker assembly approaches the mechanical
triggering lock.
Preferably, the torsion, spring is symmetrical in relation to the axis of
movement of the mobile assembly.
Such a symmetry can be explained by the translational movement
according to this axis, optimal operation of which is favored by a configurational
balance in relation to said axis.

In the invention, the mobile assembly moves by sliding and is guided in at
least one slide channel fixed in relation to the housing.
The spring acts on the mobile assembly which may disturb the direction
of movement, and consequently the path of the striker, if guiding was solely the
result of the effect of magnetic forces on the core's movement.
More precisely, the mobile assembly is made up of an overlaid magnetic
plate and striker.
These two elements exercise distinct functions, the magnetic plate or
core necessarily being made of a magnetic material which is not necessarily the best adapted for the striker, for economical or mechanical reasons depending
on the tasks entrusted to it.
According to the invention, the sliding of the magnetic plate/striker mobile
assembly is done by guiding said assembly in the slide channels symmetrically
arranged in the side cheeks located in the housing, fixed, on either side of the magnetic subassembly.
The guiding function is therefore performed in this case by pieces
forming said cheeks, which may be made of a synthetic material, molded, for
example, to which it is easy and inexpensive to give a complex shape for the
performance of various functions.
As will be shown in more detail below, said cheeks also have in particular
the function of housing the magnetic subassembly.
More precisely, each slide channel may be made up of a wall parallel to
the axis of movement of said mobile assembly, on either side of which
respectively cheeks slide, these cheeks laterally exceeding the striker and one face of the magnetic plate facing said cheeks.
The two components of the mobile assembly therefore participate in the
translational guiding.
The magnetic subassembly of the invention, beyond such a coil,
preferably comprises a trapezoidal magnetic plate cooperating with an air gap in
the yoke, also trapezoidally shaped.
According to one possible configuration, the spring stops are made up of
cheeks each having a C-shaped housing section at one part of an extremity arm

of the spring, said C-shaped section being stretched perpendicularly in relation
to the direction of movement of the mobile assembly.
These stops make it possible to position the spring while exercising
prestressing.
In a first version of the invention, the coiled portion of the spring is pulled
by the mobile assembly, and the spring stops are fixed in relation to the housing
of the device.
In this case, preferably, the central portion of the spring is wound around
the head of a hub making up a protrusion of the striker crossing and exceeding
an opening located in the magnetic plate, a portion of said striker equipped with
an impact surface situated perpendicularly to the movement and standing up in
front of the frontal edge of said plate.
In this hypothesis, the mechanical relationships, both with the spring and
with the mechanical lock performing the triggering, are taken care of by the
striker. The sole function of the magnetic plate is to pull said striker when said
plate is subjected to Laplace forces sufficient to successfully oppose the
resistive force of the spring.
Alternatively, the spring may be fixed to the housing of the device, and
the spring stops are attached to the mobile assembly.
The configuration of the magnetic subassembly of the invention is based
on that which is in particular explained in detail in patent application EP-0 23 601
76.8 of the applicant, the content of which is incorporated by reference in the
present description.
The invention will now be described in more detail, with reference to the
figures presented in the accompanying drawings, for which:
- figure 1 is a schematic illustration of the configuration of the invention,
with a diagram of the forces present at the level of the stops ;
- figure 2 shows a perspective view of the mobile assembly with a
torsion spring;
- figure 3 shows the whole of the preceding figure with the rest of the
magnetic yoke;

- figure 4 is a top view of the striker cooperating with a torsion spring ;

- figure 5 shows the cooperation of the mobile assembly with a lateral
cheek attached to the housing of the electrical device ;
- figure 6 is a top view of the configuration appearing in the preceding
figure, with the two side cheeks and without the magnetic plate;
- figure 7 is a bottom view ;
- figure 8 shows the piece on which one prefits the spring; and
- figure 9 shows said prefitting piece fixed to the side cheeks.
The appended figures 2 to 9 show a version of the invention in which the
torsion spring forms one piece with the mobile equipment.
In reference to figures 1 and 2, the torsion spring (1) comprises a central
coiled portion (2) and extremity arms spread out in a V-shape (3) and (3'). This
spring (1) is pulled by the hub (4) of a mobile assembly comprising on one hand
the striker (5) and on the other hand the core / magnetic plate (6). The
resistance opposed by the spring (1) to the movement of the mobile assembly,
5and in particular of the hub (4) on the axis x may be calculated as follows:
The spring (1) exercises a force on the stop (7). The force seen by
the stop is in accordance with the diagram. is in fact the reaction of the
stop (7) on the arm (3) of the spring (1), taking friction into account. It is
therefore separated from an angle cp of the reaction of the stop (7) on the arm (3) of the spring (1), in the absence of friction.
From which:

However, the resistant torque opposed by the spring is expressed by the
relationship:

C = kα
a being the angular variation of the angle existing between the direction
of movement x and the line joining the stop (7) to the center of the hub (4) and k, the rigidity of the spring (1). The value of the torque may also be written:

By replacing with its value with the help of , one obtains:

From which:
The component of this resistive force on the axis of movements x is then equal to:

This formula relates to only one stop (7). Given the symmetry with the
stop (7'), the total resistive force exercised by the spring (1) is in reality:

When a movement begins, the angular movement a increases and the
part of this formula due to the spring torque, namely ka / R, increases as well.
The coefficient 1/cos0 also increases slightly, because the cos 9 decreases a
little. The coefficient Fr is stable, since friction is considered constant. On the
other hand, the variable sin T, which constitutes the projection on the axis
decreases.
There is a geometric configuration such that the increases due to a and 8
do not compensate for the decrease resulting from sin T. In this configuration,
the resistive energy seen by the plate is minimized in relation to a traditional
system.
In reference to figure 3, the mobile plate (6) associated with the striker (5)
and the spring (1) is shown in the broadened context of its association with the
magnetic yoke, said yoke being made up of two symmetrical parts (8, 8'). This
yoke comprises a first air gap (9) in which the plate (6) moves, and a second air
gap (10) intended to receive the mobile contact (not shown).
Figure 4 shows, in more detail, the striker (5) which is present in the form
of a sliding carriage equipped with a central hub (4), cheeks (11, 11') intended
to slide in sliding channels (see below), said chariot having, in front in the
direction of movement in case of short circuit, a projection equipped with a flat
frontal impact surface (12).
Figure 5 shows the mobile equipment made up of the plate (6), the striker
(5) and the spring (1) placed in position, meaning situated in relation to other
elements either of the magnetic subassembly, or intended for its immobilization
in the housing. Thus, said mobile equipment is above the coil (13) of said
magnetic subassembly, which in fact forms three-quarters of the loop made by a
magnetic plate folded around a core (14) traditionally made up of stacked
plates. The coil (13) / core (14) assembly is inserted in a side cheek (15) which

participates in the positioning of a certain number of elements of the circuit-
breaker. In principle, the coil (13) and the core (14) are masked by one of the
parts (8') of the yoke, which is not shown here. There is also a second cheek
symmetrical to the first, which makes it possible to complete the lodging of the
magnetic subassembly and which is also not shown in figure 5 so as not to
hinder the readability of the figure.
This second cheek (15') is, however, shown in figure 6, in which the
quasi-entirety of the magnetic subassembly, with the exception of the spring (1)
and the upper parts of the mobile equipment, namely the hub (4) and the
forward projection with its impact surface (12), is masked. In fact, when the two
legs (15) and (15') are assembled, their upper part makes up a window (16)
enabling the movement of the mobile equipment, and contributing at least
partially to its guiding in the direction of the arrow (F).
This guiding is done, as appears in figures 5 to 7, by flat parallel walls
(17, 17') located under the upper part of the legs (15, 15') with which the lateral
cheeks (11, 11') of the mobile striker (5) may cooperate during sliding. One wall
of the magnetic plate (6) facing said cheeks (11, 11') slides on the other side of
each wall (17, 17'), which may moreover be equipped with positioning guides
(19,19').
The spring (1), the ends (3, 3') of which appear, is topped by a sort of
cover or hood (18) which is mounted on the upper parts of the legs (15, 15').
This cover (18), which enables pre-assembly of the spring (1), appears in figure
8. It contains the stops (7, T) which determine in particular the prestressing of
the torsion spring (1), and thereby make it possible to adapt it to the capacity
and sensitivity of the circuit-breaker. The stops (7, 7') contain a C-shaped
lodging for the ends (3, 3') of the spring (1).
When the cover or cap (18) is mounted, by embedment, on the two legs
(15, 15'), as appears in figure 9, the upper part of the mobile assembly is not
completely covered in order to preserve the function of the flat impact wall (12)
of the striker (5). This wall must indeed be able to come into contact with the
magnetic triggering lock, of which at least one portion is inserted between the
two legs (15, 15') so that contact may be realized.

We Claim :
1. Magnetic subassembly for electrical equipment of the circuit-breaker
type, made up of an inductive coil associated with a magnetic yoke (8, 8') and
with a moving core (6)/ striker (5)/assembly that can move translatably against a
spring (1), characterized in that said spring is a torsion spring with a central
coiled central portion (2) and two end arms (3, 3') opening out in a V-shape and
bearing against stops (7, 7'), the spring (1) and said stops (7, 7') being moved
relatively such that the distance between the stops (7, 7') and the central portion
(2) of the spring (1) in the direction of the translation increases as the air gap (9)
arranged between the core (6) and the yoke (8, 8') closes.
2. Magnetic subassembly as claimed in the preceding claim, wherein the
torsion spring (1) exhibits a symmetry with respect to the axis of displacement
of the moving assembly (5, 6).
3. Magnetic subassembly as claimed in one of the preceding claims,
wherein the moving assembly (5, 6) moves by sliding and is guided in at least
one runner that is fixed relative to the casing.
4. Magnetic subassembly as claimed in any one of the preceding claims,
wherein the moving assembly (5, 6) is formed by a magnetic pallet (6) and by a
striker (5) which are arranged one on the other.
5. Magnetic subassembly as claimed in the preceding claim, wherein the
sliding of the moving magnetic pallet (6) /striker (5) assembly is achieved by
guiding said assembly in runners made symmetrically in the side panels (15)
secured in the casing on either side of the magnetic subassembly.
6. Magnetic subassembly as claimed in the preceding claim, wherein each
runner is formed by a wall (17, 17') parallel to the axis of displacement of said
moving assembly (5, 6), on either side of which slide respectively, tabs (11, 11')
projecting laterally from the striker (5) and a face of the magnetic pallet (6)
oriented to face said tabs (11, 11').

7. Magnetic subassembly as claimed in any of claims 4 to 6, wherein the
pallet (6) is of trapezoidal shape cooperating with an air gap (9) of the yoke (8,
8') also of trapezoidal shape.
8. Magnetic subassembly as claimed in any one of the preceding claims,
wherein the stops (7, 7') for the spring are formed by tabs each providing a
housing having a C-shaped cross-section at one part of an end arm (3, 3') of the
spring (1), said C-shaped cross-section being understood to be perpendicular to
the direction of displacement of the moving assembly (5, 6).
9. Magnetic subassembly as claimed in any one of the preceding claims,
wherein the coiled portion (2) of the spring (1) is carried by the moving assembly
(5, 6), and the stops (7, 7') for the spring (1) are fixed relative to the casing of
the equipment.
10. Magnetic subassembly as claimed in the preceding claim, wherein the
central portion (2) of the spring (1) is wound around the top part of a shaft (4)
forming a protuberance from striker (5) passing through and projecting out of a
hole made in the magnetic pallet (6), a portion of said striker (5) equipped with
an impact surface (12) oriented perpendicularly to the displacement being
arranged in front of the frontal edge of said pallet (6).
11. Magnetic subassembly as claimed in any one of claims 1 to 8,
wherein the spring (1) is fixed to the casing of the equipment, and the stops (7,
7') for the spring (1) are secured to the moving assembly (5, 6).

ABSTRACT

MAGNETIC SUB-ASSEMBLY FOR ELECTRICAL EQUIPMENT OF
CIRCUIT-BREAKER TYPE
The present invention discloses magnetic subassembly for an electrical device of the circuit-
breaker type, made up of an inductor coil associated with a magnetic yoke (8, 8') and with a
core (6)/mobile striker (5)/mobile assembly in translation against a torsion spring (1) with a
coiled central portion (2) and two extremity arms (3, 3') spread out in a V-shape pushing
against stops (7, 7'), the spring (1) and said stops (7, 7') being driven by a relative movement
such that the distance between the stops (7, 7') and the central portion (2) of the spring (1) in
the direction of the translation increases during closing of the air gap (9) positioned between
the core (6) and the yoke (8, 8').

MAGNETIC SUB-ASSEMBLY FOR ELECTRICAL EQUIPMENT OF CIRCUIT-BREAKER TYPE

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