EP2345056B1 - Electrical overcurrent relay having a rocker which is borne such that it can pivot - Google Patents

Abstract

The invention relates to an overcurrent relay, having a rocker (20) which is borne such that it can pivot and on which at least one moving contact piece (11) of a contact point (12) is borne, wherein, in the event of an overcurrent, the rocker changes from a first closed position to a second closed position as a result of the influence of a thermal release, and having a switching device (40), which can be switched between a first and a second position, for manual or automatic resetting of the rocker from the second closed position to the first closed position, wherein a. the rocker is held by a snap-action spring in its first or second closed position and can snap over between the two closed positions, via a dead-centre position, against the resetting force of the snap-action spring, wherein b. a function spring interacts with the rocker such that it assists the rocker in snapping over from the first closed position to the second closed position, and wherein c. the function spring can enable or inhibit the rocker snapping back from the second closed position to the first closed position, under the influence of the switching device.

Description

The invention relates to an overload relay, with a pivotally mounted rocker on which at least one movable contact piece of a contact point is mounted, wherein the rocker overflow occurs in the event of overcurrent due to the action of a thermal release from a first closed position to a second closed position, and with a between a first and a second position convertible changeover to manual or automatic provision of the rocker from the second to the first closed position, according to the preamble of claim 1.

An electrical overload relay is used to protect an electric motor against overcurrents. Known overcurrent relays have as thermal tripping elements thermostatic bimetals, which are heated by the overcurrents and bend out, thereby opening or closing a switch contact point.

US 3866 156 discloses an overload relay according to the preamble of claim 1.

The DE 299 17 173 U1 shows an actuating device for an overload relay with a rocker on which two contact bridges for electrically conductive bridging two Festkontaktstückpaare are resiliently mounted. The two Festkontaktstückpaare are designed as opener / closer - pair. In the idle state, the rocker is in its first closed position and the first contact point, the opener, is closed, and the second contact point, the normally open, is open. If an overcurrent heats the bimetallic strip, it acts on the rocker, possibly with the interposition of further mechanical lever or slide arrangements, causing it to snap over into its second closed position. In the second closed position, the first contact point is then opened and the second contact point is closed.

If the overcurrent is no longer present and the thermostatic bimetal has deformed back into its original position, then the rocker could snap back into its first closed position. In a generic overload relay there are two modes of operation, manual and automatic operation.

In manual operation, the rocker remains in its second closed position until it is forcibly returned to its first closed position due to the operation of a reset member by an operator from the outside.

In automatic mode, the rocker automatically snaps back to its first closed position as soon as the overcurrent stops.

A generic overload relay has a changeover device, which can be changed from outside the device by an operator from a first to a second position. For example, the first position corresponds to the setting "Automatic mode", the second position corresponds to the setting "Manual mode".

To snap the rocker a snap-action switch is used in a generic overload relay. In this, the rocker from the first closed position over a dead center position snaps into the second closed position. In automatic mode, the contact gap on the normally closed contact is reduced so much that the snap-action switching point of the snap-action mechanism remains in front of the dead center position. As a result, the rocker then immediately snaps back into its first closed position when the overcurrent is no longer present. In manual operation, the contact distance at the NC is greater, thus the snap-action point is behind the dead center. After snapping into the second closed position, the rocker then remains there until it is manually forced back into the starting position.

Due to the reduced contact spacing, generic overload relays known in this way therefore exhibit a reduced dielectric strength and a reduced switching capacity in automatic mode.

It is the object of the present invention to provide an overload relay which has the same switching capacity both in automatic and in manual operation, and has a sufficiently high dielectric strength, which ensures that the device is also in automatic mode at higher voltages, about 690 V, can be used.

This object is achieved by the features of claim 1.

The invention is therefore characterized in that the rocker is held by a snap spring in its first and second closed position and can snap against the restoring force of the snap spring on a dead center between the two closed positions that cooperates with the rocker a functional spring, that this one Snapping the rocker supported from the first to the second closed position, and that the functional spring under the influence of the switching device can release a snap back of the rocker from the second to the first closed position or block.

In the actuating device according to the invention, the rocker both in automatic and in manual operation snaps from its first stable closed position to its second, stable closed position. As a result, the contact distance in manual and in automatic mode is the same. The distinction between the manual and the automatic operation by means of the inventively provided functional spring under the influence of the switching device.

According to a particularly advantageous embodiment, the rocker presses in its first stable closed position, the function spring counter to their restoring force in a first operative position in which the function spring acts by its restoring force the rocker in the direction of the second closed position. As a result, the functional spring acts both in automatic and in manual operation to assist opening.

An advantageous embodiment is characterized in that the changeover means comprises a push button which is depressed in its first position and thereby holds the functional spring in an intermediate position in which it releases the rocker after overshooting the dead center in the second closed position to snap back into the first closed position , When the changeover device is in the first position, the overload relay is thus in automatic mode, because an immediate snap back of the rocker after the overcurrent has subsided is made possible.

An advantageous embodiment is characterized in that the push button releases the functional spring in its second position, so that it acts on the rocker even after exceeding its dead center in the direction of the second closed position. When the changeover device is in the second position, the overload relay is thus in manual operation, because an immediate snap back of the rocker after the overcurrent has subsided is prevented by the functional spring, which continues to open the rocker. Only by manual reset from the outside can the rocker be snapped back.

An advantageous embodiment is characterized in that a first rocker arm cooperates with a first contact point and a second rocker arm with a second contact point, so that closed in the first closed position of the rocker the first contact point and the second contact point, and in the second closed position of the rocker the first contact point is opened and the second contact point is closed. Thus, the application of an actuator according to the invention in an overload relay with an opener / closer - arrangement is possible.

An advantageous embodiment is characterized in that a first contact bridge is mounted on the first rocker arm and a second contact bridge for the electrically conductive bridging of at least two fixed contact pieces is mounted on the second rocker arm. Thus, the application of an actuator according to the invention in an overload relay with an opener / closer arrangement is possible in which each contact point as a double contact point with two fixed contact pieces, which can be bridged by a contact bridge carrying the two movable contacts, possible.

An advantageous embodiment is characterized in that the contact pressure force is applied to the second contact point in the second closed position of the rocker by the snap spring. Advantageously, this simplifies the mechanical structure, since a separate contact pressure spring for the second contact point is not required.

An advantageous embodiment is characterized in that the contact pressure force is applied to the first contact point in the first closed position of the rocker by a contact pressure spring. In a further advantageous manner, the pivoting back of the rocker from the second closed position over the dead center in the first closed position is supported by the contact pressure spring after elimination of the effect of the thermal release, so that a snap back of the rocker can be made from the second to the first closed position.

Further advantageous embodiments and improvements of the invention can be found in the dependent claims.

Reference to the drawing, in which two embodiments of the invention are shown, the invention and further advantageous refinements and improvements and further advantages of the invention will be explained and described in detail.

Fig. 1

schematisch eine Seitenansicht einer erfindungsgemäßen Betätigungseinrichtung für ein Überlastrelais mit einer Einzelunterbrechung, in der Automatik-Betriebsart, mit geschlossenem Öffner,

Fig. 2

schematisch eine Seitenansicht einer erfindungsgemäßen Betätigungseinrichtung für ein Überlastrelais mit einer Einzelunterbrechung, in der Automatik-Betriebsart, mit geschlossenem Schließer,

Fig. 3

schematisch eine Seitenansicht einer erfindungsgemäßen Betätigungseinrichtung für ein Überlastrelais mit einer Einzelunterbrechung, in der manuellen Betriebsart, mit geschlossenem Öffner,

Fig. 4

schematisch eine Seitenansicht einer erfindungsgemäßen Betätigungseinrichtung für ein Überlastrelais mit einer Einzelunterbrechung, in der manuellen Betriebsart, mit geschlossenem Schließer,

Fig. 5

schematisch eine Seitenansicht einer erfindungsgemäßen Betätigungseinrichtung für ein Überlastrelais mit einer Doppelunterbrechung, in der Automatik-Betriebsart, mit geschlossenem Öffner,

Fig. 6

schematisch eine Seitenansicht einer erfindungsgemäßen Betätigungseinrichtung für ein Überlastrelais mit einer Doppelunterbrechung, in der Automatik-Betriebsart, mit geschlossenem Schließer,

Fig. 7

schematisch eine Seitenansicht einer erfindungsgemäßen Betätigungseinrichtung für ein Überlastrelais mit einer Doppelunterbrechung, in der manuellen Betriebsart, mit geschlossenem Öffner, sowie

Fig. 8

schematisch eine Seitenansicht einer erfindungsgemäßen Betätigungseinrichtung für ein Überlastrelais mit einer Doppelunterbrechung, in der manuellen Betriebsart, mit geschlossenem Schließer.

Show it:

Fig. 1

schematically a side view of an actuating device according to the invention for an overload relay with a single break, in the automatic mode, with a closed NC,

Fig. 2

1 is a schematic side view of an actuating device according to the invention for an overload relay with a single interruption, in the automatic operating mode, with the normally open contact,

Fig. 3

1 is a schematic side view of an actuating device according to the invention for an overload relay with a single interruption, in the manual operating mode, with a normally closed contact,

Fig. 4

1 is a schematic side view of an actuating device according to the invention for an overload relay with a single interruption, in the manual operating mode, with the normally open contact,

Fig. 5

schematically a side view of an actuator according to the invention for an overload relay with a double break, in the automatic mode, with a closed NC,

Fig. 6

1 is a schematic side view of an actuating device according to the invention for an overload relay with a double interruption, in the automatic operating mode, with the normally open contact,

Fig. 7

schematically a side view of an actuator according to the invention for an overload relay with a double break, in the manual mode, with a closed NC, and

Fig. 8

schematically a side view of an actuator according to the invention for an overload relay with a double break, in the manual mode, with a normally open contact.

In all figures, identical or equivalent components or assemblies are designated by the same reference numerals.

FIG. 1 shows a partial section of an electrical overcurrent relay 1, with a housing 2 in which a shift key 40 in the form of a push button can be pressed by actuation from outside the housing and let out again. The shift key 40 is shown schematically as a cylindrical body with an actuating extension 41, wherein the cylindrical body 40 is accessible with its operating side 42 from outside the housing for actuation. The exact nature of the storage of the shift key, such as their interaction with a return spring and the necessary locking and unlocking mechanisms are not shown here in detail, since any known configuration can be used for this purpose.

In the housing 2, a rocker 20 is further arranged in the form of a double lever, with a first arm 22 and a second arm 23. The first arm 22 is associated with a first contact point 17. The second arm 23 is associated with a second contact point 12.

The rocker 20 has approximately centrally a bearing extension 21 which is integrally formed approximately perpendicular to the first arm 22 and is mounted with its free end in a housing-fixed bearing cup 201. As a result, a pivot point 202 for the rocker 20 is formed on the bearing cup, by which it can be pivoted in the direction of arrow P. The rocker 20 is supported with its bearing extension 21 so on a cutting bearing, which includes the bearing cup 201 and the free end of the bearing extension 21. Of course, other known storage methods and devices can be used, as long as they perform the same function, namely to allow a pivotable mounting of the rocker 20 in the housing 2.

Approximately in the middle between the first and second arm 22, 23, in the neck region of the bearing extension 21 is located on the rocker 20, a pin 24. At this pin 24 a snap spring 30 is mounted, the other end to a below the cutting bearing and the Lagepfanne 201 fixed housing anchored point 31 is attached. The imaginary connecting line between the pin 24 and the pivot 202 bears the reference numeral 241.

The rocker 20 with the snap spring 30 forms a snap-action mechanism.

The restoring force of the snap spring 30 acts on the articulation point 24 and acts in the direction of arrow K, on the left, the second arm associated side of the rocker 20. As a result, it pulls the rocker 20 counterclockwise to a position in which the rocker 20 itself in its first stable position or in its first closed position.

In the first stable position of the rocker 20 according to FIG. 1 the first contact point 17 is closed, this is therefore also referred to as an opener. The second contact point 12 is open, it is therefore also referred to as a closer.

The first contact point 17 comprises a fixed contact 15 and a movable contact 16 mounted on a pivotably mounted contact arm 18. In the closed state according to FIG Fig. 1 the contact pressure force is applied to the first contact point 17 by a contact pressure spring 60 acting on the contact arm 18. This is hinged at its other end to an adjusting element 70, which can be adjusted in the direction of arrow E up or down, so that the contact pressure force is adjustable.

The second contact point 12 comprises a fixed contact 10 and a movable contact 11 fastened to the free end of the second arm 23 of the rocker 20. In the illustration according to FIG FIG. 1 the second contact point is open. In its closed position, which will be described below, the contact pressure force is applied to the second pad 12 by the snap spring 30, as will be shown below.

In the housing 2, a function spring 50 is further attached. Here, this is designed as a leg spring with a first and a second spring arm 51, 52 which is mounted in a housing-fixed axis 53 and the restoring force acts in the opening direction of the angle formed by the two spring arms 51, 52 angle.

The first arm 51 is supported fixed to the housing, and the second arm 52 presses with its free end resiliently against a stop 25 on the second arm 23 of the rocker 20 and acts on these in the direction of arrow F with a functional force, which Rocker 20 is looking to turn clockwise. The function spring 50 is here in its first operative position. The pulling force K, which exerts the snap spring 30 on the rocker 20 in the counterclockwise direction, is so great that it holds the rocker 20 against the restoring force F of the functional spring 50 in the first stable position.

The push button 40 is depressed so that its actuating extension 41 comes to lie in the vicinity of the second arm 52 and thereby allows the second arm 52 only a very small range of motion upwards, ie in the opening direction of the leg spring 50. In this position of the push button, the overcurrent relay is in the automatic mode, as will be apparent below. The push button can be executed and stored in a known manner. It can be held against the restoring force of a spring, for example, by pressing and twisting in a latching position in the depressed position. To release, it is then first turned back out of the detent position so that the spring can then push it out again.

In the FIG. 2 the overcurrent relay 1 is shown in the tripped state. The zugfederbte by the snap spring 30 rocker 20 is pivoted or snapped clockwise into its second stable position or its second closed position. Starting from the first closed position to FIG. 1 is the transition to the second closed position after Fig. 2 triggered by a release force A, the thermal release, optionally with the interposition of an actuating element and a lever and / or slide assembly - not shown here - on the bearing extension 21 and on the snap spring 30, so on the snap-action mechanism exerts. This can be done so that the actuator acts on the snap spring and presses clockwise down to the left until the dead center, also referred to as dead center, reached and overcome and the snap spring 30 then the rocker 20 in the second stable closed position draws.

The snapping can also be caused by the fact that the actuating element exerts a triggering force on the bearing extension 21. The triggering force is in FIG. 2 indicated for this case by an arrow A. In principle, all known Tripping and slide arrangements are used according to the invention, therefore, it will not be discussed in more detail in the present invention and the figures.

Starting from the first closed position, the release force A, supported by the functional force F of the functional spring 50, first pivots the rocker 20 clockwise until the force arrow K of the snap spring 30 is in line with the imaginary connecting line 241 between the pin 24 and the pivot point 202 is located. This is the dead center or the dead center of the rocker 20. If the release force A presses in this position a little further clockwise, then pulls the force of the snap spring 30 to the right of the imaginary connection line 241, so that thereby further pivots the rocker in a clockwise direction and in their second stable position according to Fig. 2 snaps.

In the second stable position, also called the second closed position, the rocker 20, the second contact point 12 is closed and the first Kontaktste !! e 17 is open, wherein at the first contact point 17, the full contact distance is reached. In this case, the second arm 22 of the rocker 20 presses the contact arm 18 against the restoring force of the contact pressure spring 60 down.

The contact pressure force at the second pad 12 is applied by the snap spring 30.

The second spring arm 52 of the function spring 50 is blocked by the actuating extension 41 of the shift key 40, so that it can no longer press on the stop 25 in the second closed position of the rocker 20.

The restoring forces of the contact pressure spring 60, the snap spring 30 and the release force A are coordinated so that the superposition of the release force A with the force K of the snap spring 30 is sufficient to keep the first contact point 17 against the restoring force of the contact pressure spring 60 open. The magnitude of the restoring force of the contact pressure spring 60 can be adjusted with the adjusting member 70.

Now, if the overcurrent is no longer applied, so eliminates the triggering force A again. The force K of the snap spring 30 alone can not hold the rocker 20 against the restoring force of the contact pressure spring 60. Therefore, the rocker 20 is now pivoted counterclockwise under the influence of the contact pressure spring 60 in the dead center and a little way beyond, from where they return to their first stable position FIG. 1 snaps.

The counterclockwise pivoting is possible because the second spring arm 52 of the function spring 50 can no longer press on the stop 25 and thus the rocker 20 is released for pivoting back. The snap back into the first stable position takes place automatically after elimination of the overcurrent. Therefore, the overcurrent relay 1 is in the in the FIGS. 1 and 2 shown depressed position of the shift key 40 in the automatic mode.

About the adjustment 70, the restoring force of the contact pressure spring 60 can be adjusted so that it is neither too large, thereby opening the first contact point 17 would be prevented, nor too small, whereby an automatic reset of the rocker 20 could not be done.

The Figures 3 and 4 show the overcurrent relay 1 in the "manual reset" mode. The difference to that in the FIGS. 1 and 2 shown mode is that the shift key 40 is now exposed, so that thereby a greater distance between the actuating extension 41 of the shift key 40 and the second spring arm 52 of the function spring 50 is, as in the operating mode "automatic" according to the FIGS. 1 and 2 with depressed shift key.

As a result, the second spring arm 52 of the functional spring 50 is no longer blocked. He now presses with its restoring force F also in the second stable position of the rocker 20 according to FIG. 4 further against the stop 25. Its restoring force F supports the release force A and the pulling force K of the snap spring 30 in this position.

After elimination of the overcurrent and thus falling off the release force A is from the superposition of the restoring force F of the functional spring 50 with the tensile force K of Snap spring 30 resulting force on the rocker 20 still large enough to this against the restoring force of the contact pressure spring 60 in the second stable position according to Fig. 4 to keep.

If the rocker 20 is to be set back into its first stable position from this position, a corresponding manual reset force M must be exerted on the rocker from the outside via a reset button, which forcibly pivots it counterclockwise over the dead center position, so that it can move from From there back to the first stable position can snap back.

The reset force M can for example be exerted on the first arm 23 of the rocker 20 via a suitable lever arrangement, as indicated by the arrow M in Fig. 4 indicated. The arrangement of an externally operable reset button or reset switch with an associated lever assembly for acting on the rocker in the manual reset operation is known in principle and should therefore not be shown here for the sake of clarity of illustration.

The FIGS. 5 to 8 show an electrical overload relay 1 similar to that in the Figures 1 to 4 shown, with the difference that in the embodiment according to the FIGS. 5 to 8 the first and second contact points 17, 12 are each designed as a double contact point.

The first contact point 17 thus comprises two fixed contacts 151, which are conductively bridged when the contact point is closed via two movable contact pieces attached to a movable contact bridge 161. As an adjusting element for the contact pressure spring 60 is here an adjusting screw 701st

The second contact point 12 comprises two fixed contacts 101, which are conductively bridged when the contact point is closed via two movable contact pieces attached to a movable contact bridge 111.

Otherwise, the correspond in the Figures 5 and 6 Positions shown the automatic mode, analogous to the description of FIGS. 1 and 2 , The in the characters 7 and 8th shown positions correspond to the manual operation, analogous to the Figures 3 and 4 described.

The contact bridges 111, 161 can also be designed as so-called double contact bridges. A double contact bridge connects two adjacent pairs of contacts, ie a total of 4 contacts, with each other.

Other necessary components of an overcurrent relay, such as terminals for the working circuit and the auxiliary circuits, the bimetals themselves or slide assemblies that transmit the movement of the bimetals on the rocker, are not shown in the figures, since they either do not differ from known arrangements or subject be further inventions.

LIST OF REFERENCE NUMBERS

1

Overload relay

2

casing

10

Fixed contact normally open

11

Movable normally open contact

12

Second contact point, normally open

15

Fixed contact, normally closed contact

16

Movable NC contact

17

First contact point, NC contact

18

contact

20

seesaw

21

Bearing extension

22

first arm

23

second arm

24

spigot

25

attack

30

catch spring

31

articulation

40

Switching device, push button

41

Actuating extension

42

operating side

50

Operation spring

51

First spring arm

52

Second spring arm

53

Housing fixed axis

60

Contact pressure spring

70

adjustment

101

Fixed contact normally open

111

Mobile Normally Open Contact Bridge

151

Fixed contact NC

161

Movable NC contact bridge

201

bearing cup

202

pivot point

241

connecting line

701

adjustment

P

arrow

K

force arrow

e

Setting direction

A

release force

M

Reset force

F

function power

Claims (9)

1. Overload relay (1) with a pivotably mounted rocker (20), on which at least one movable contact piece (11) of a contact point (12) is mounted, the rocker (20) moving from a first closed position into a second closed position in the event of an overcurrent owing to the effect of a thermal release, and with a switchover device (40), which can change over between a first and a second position, for manually or automatically restoring the rocker (20) from the second closed position into the first closed position, wherein
   the rocker (20) is held in its first or second closed position by a snap-action spring (30) and can snap over between the two closed positions via a dead-center position counter to the restoring force of the snap-action spring (30), and wherein
   a functional spring (50) interacts with the rocker (20) in such a way that said functional spring assists the rocker (20) in snapping over from the first closed position to the second closed position, characterized
   in that the functional spring (50) can, under the influence of the switchover device (40), release or block snapping-back of the rocker (20) from the second closed position into the first closed position.
2. Overload relay (1) according to Claim 1, characterized in that the rocker (20), in its first stable closed position, pushes the functional spring spring (50) counter to its restoring force into a first active position, in which the functional spring spring (50), by virtue of its restoring force, acts on the rocker (20) in the direction of the second closed position.
3. Overload relay (1) according to Claim 2, characterized in that the switchover device (40) comprises a pushbutton (40), which is depressed in its first position and, in the process, holds the functional spring (50) in an intermediate position, in which said functional spring spring releases the rocker (20) once the dead-center position has been crossed over in the second closed position for snapping back into the first closed position.
4. Overload relay (1) according to Claim 3, characterized in that the pushbutton (40), in its second position, releases the functional spring spring (50), with the result that said functional spring spring acts on the rocker (20), also once its dead-center position has been crossed over, in the direction of the second closed position.
5. Overload relay (1) according to one of the preceding claims, characterized in that a first rocker arm (22) interacts with a first contact point (17) and a second rocker arm (23) interacts with a second contact point (12), with the result that, in the first closed position of the rocker (20), the first contact point (17) is closed and the second contact point (12) is open and, in the second closed position of the rocker (20), the first contact point (17) is open and the second contact point (12) is closed.
6. Overload relay (1) according to Claim 5, characterized in that a first contact link (161) is mounted on the first rocker arm (22) and a second contact link (111) is mounted on the second rocker arm (23) for providing an electrically conductive link between in each case at least two fixed contact pieces (151; 101).
7. Overload relay (1) according to Claim 5, characterized in that the contact-pressure force at the second contact point (12) is applied in the second closed position of the rocker (20) by the snap-action spring (30).
8. Overload relay (1) according to Claim 5, characterized in that the contact-pressure force at the first contact point (17) is applied in the first closed position of the rocker (20) by a contact-pressure spring (60).
9. Overload relay (1) according to Claim 8, characterized in that, after cessation of the action of the thermal release, the action of the rocker (20) pivoting back out of the second closed position via the dead-center position into the first closed position is assisted by the contact-pressure spring (60), with the result that it is possible for the rocker (20) to snap back out of the second closed position into the first closed position.

Images