EP1402552B1 - Adjusting device for a thermal trip - Google Patents

Abstract

An adjusting device is for a thermal trip of a switchgear. It includes a bimetal, which is held in a fixed manner on a bimetal support, whose free end is located at a distance from a tripping lever, and which increasingly acts upon this tripping lever in a tripping direction as a result of thermal deformation. A distance can be adjusted by deforming the bimetal support. The adjusting device is particularly suited for use in circuit-breakers or the like.

Description

The invention relates to an adjusting device for a thermal release of a switching device according to the preamble of claim 1. Such an adjusting device is known from EP 0 913 848 A2. Under switching device while mechanical or electromechanical switching devices, especially circuit breakers, circuit breakers, relays, contactors or the like understood.

Such a switching device is used to connect a circuit to a power grid and for manual and automatic disconnection of the circuit from the network when the current exceeds a predetermined value. For example, a miniature circuit breaker protects cables in installations and systems against overload and short circuits. In a network with shutdown by overcurrent protective devices prevents such a switching device in case of failure in addition to the persistence of high contact voltages.

When switching the switching device or circuit breaker is a power storage, eg. As a spring, as part of a mechanical switching mechanism or switching mechanism clamped, which is released during the tripping operation and actuates the switch. In this case, the switching device comprises a thermal release in the form of a usually strip-shaped bimetal, which triggers delay-dependent delayed overload. The tripping operation is triggered by a thermal deformation of the bimetallic strip as a result of the overcurrent carried over this.

For this purpose, the bimetallic strip acts on a release lever spaced opposite its free end and mechanically coupled to the switch lock. Thus unlatched about this the bimetallic strip the switching mechanism, while the energy storage of the switching mechanism opens a movable contact or moving contact by this lifts from a fixed contact. In addition, the switching device usually also includes an instantaneous triggering magnetic or electromagnetic trigger for high surge and short circuit currents.

The distance between the free end of the bimetal and the release lever is adjustable, what an adjusting screw is usually provided for. Switching devices in which such an adjusting screw are used for bimetallic adjustment are known, for example, from DE 1 904 731 A1 and from EP 0 143 981 A1, EP 0 412 953 A3, from EP 0 338 868 A1. However, the use of an adjusting screw is associated with corresponding manufacturing and manufacturing costs.

From EP 0 913 848 A2 a method for thermal calibration of the triggering mechanism of a switching device and a corresponding triggering mechanism are also known, in which the adjustment takes place thermally by means of a laser.

The invention is therefore based on the object, a particularly inexpensive and easy to handle adjusting device for a switching device, in particular for a circuit breaker specify.

This object is achieved by the features of claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.

The bimetal has a parallel to the bimetal and connected to the contact end holding leg with a fixation as a fixed attachment point. At this preferably step-shaped curved holding leg closes on the one hand an effective as an adjustment range handling leg and on the other hand via a bend at least approximately U-shaped fixing leg of the bimetallic carrier. The step contour of the retaining leg allows the holder of different lengths, in particular also indirectly heated bimetals by means of the same bimetal. As a result, the number of different thermal releases that need to be provided or kept available for different types of switching devices, can be significantly reduced and kept very low overall.

The adjustment of the distance of the bimetal to the release lever and thus the adjustment of the thermal release takes place according to the invention by twisting the transverse to the holding leg and acting as an adjustment of the bimetal carrier handling leg. For this purpose, the handling leg is advantageously designed like a perforated plate. In this case, a number of through holes, preferably in the form of round holes are introduced into the handling leg.

The handling leg of the bimetallic carrier may be fixed in position in a stationary housing opening or contour which is also effective as a rotary opening. For this purpose, the handling leg is expediently positioned in the region of the free end of the bimetal. Alternatively, the bimetallic support may be formed like a loop, wherein the handling leg is then supported on the front side of the bimetallic support. In this embodiment, a predetermined bending point is preferably formed in the region of the loop vertex of the bimetal carrier.

The switching device has a housing which is formed from urea and / or melamine resin molding compound. The urea or melamine resins belonging to the family of thermosetting plastics are particularly suitable for a cost-reducing production of mass and series products.

The advantages achieved by the invention are, in particular, that this is deliberately deformed by suitable design and arrangement of a bimetallic carrier carrying the bimetal and thus a simple and inexpensive, possibly automatically adjusting adjusting device for a thermal release of a switching device can be provided. The distance of the free end of the bimetal to the release lever is on the one hand by deformation, especially by means of a tool of handling or holding leg adjustable or adjustable, or on the other hand by automatic bending of the bimetallic strip in an age-related Gehäusenachschwindung be maintained.

This serving for bimetallic adjustment mechanism in which the bimetal holding bimetallic support is mounted fixed to the housing via two attachment points, of which a fixed attachment point stable storage of the bimetal - and thus the thermal release - ensures and the other attachment point the adjustment means for adjusting the bimetal by deformation includes, allows a finely adjustable and exact adjustment of the thermal release.

FIG 1 und 2

in Draufsicht bzw. in perspektivischer Darstellung einen in ein Schaltgerät endmontierten thermischen Auslöser mit einer Justiervorrichtung mit verdrillbarem Bimetallträger mit kurzem Bimetall,

FIG 3 und 4

in Darstellungen gemäß den Figuren 1 bzw. 2 die Justiervorrichtung mit langem Bimetall,

FIG 5a bis 5d

unterschiedliche Geometrien eines Handhabungsschenkels der Justiervorrichtung gemäß den Figuren 1 bis 4,

FIG 6 und 7

in einer Seitenansicht bzw. in perspektivischer Darstellung eine Justiervorrichtung mit alternativ verformbarem Bimetallträger,

FIG 8 bis 11

Schnittdarstellungen verschiedener Varianten des Verformungsmechanismus der Justiervorrichtung, und

FIG 12 und 13

in Draufsicht bzw. in perspektivischer Darstellung einen in ein Schaltgerät endmontierten thermischen Auslöser mit einer weiteren Justiervorrichtung mit einem Einstellmittel für den Bimetallträger mit kurzem Bimetall.

Embodiments of the invention will be explained in more detail with reference to a drawing. Show:

1 and 2

in top view and in perspective view of a finally mounted in a switching device thermal release with an adjustment device with twistable bimetallic with a short bimetal,

3 and 4

in illustrations according to the figures 1 and 2, the adjustment device with a long bimetal,

FIGS. 5a to 5d

different geometries of a handling leg of the adjusting device according to the figures 1 to 4,

FIGS. 6 and 7

in a side view or in perspective an adjusting device with alternatively deformable bimetallic,

FIGS. 8 to 11

Sectional views of different variants of the deformation mechanism of the adjusting device, and

FIGS. 12 and 13

in plan view and in perspective view of a finally mounted in a switching device thermal release with a further adjusting device with a setting means for the bimetallic with a short bimetal.

Corresponding parts are provided in all figures with the same reference numerals.

Figures 1 to 4 show a detail of a switching device 1 with the housing cover lifted off the housing 2, in which the essential parts of an adjustable thermal release are shown visible. The thermal release comprises a bimetallic strip 3, whose contact end 3a is integrally connected to a bimetallic support 4 and thus held stationary. The bimetal 4 is electrically connected to a terminal 5 for power management via the switching device 1.

The free end 3b of the bimetal 3, that is, the bimetal, is a trigger lever 6 spaced opposite, which is coupled to a non-illustrated rear derailleur or switch lock in a conventional manner. This distance A between the bimetallic tip 3b and the release lever 6 is adjustable by bending or deformation of the bimetal 4.

The bimetallic support 4 is bent or bent several times and additionally shaped like a step. In this case, a bimetal 3 with its contact end 3a can be fixed at each stage S1, S2 and thus at different positions or connection points of the bimetallic support 4. As a result, both a short bimetal 3 according to Figures 1 and 2 and a comparatively long bimetal 3 according to Figures 3 and 4, which can be designed to be heated indirectly, on the same bimetallic 3 can be fixed or attached. Thus, the thermal release for different currents with optimal material savings interpretable.

The bimetal beam 4 has a handling leg 4a and a transverse thereto, i. at least approximately at right angles extending holding leg 4b. With this holding leg 4b, the contact end 3a of the bimetal 3 is firmly bonded. The holding leg 4b merges at a bending point 8 into a fixing leg 4c, which itself is bent approximately in a U-shape. With this fixing leg 4c of the bimetallic support 4 is fixed in position in the housing 2 by corresponding housing structures or - contours 9 and clamped by means of a terminal screw 11. In this case, the holding leg 4b is at least part of the leg length without installation in the housing 2 a. In the region of the steps S1 and S2, beads 12 are introduced into the holding limb 4b, so that a relatively thin sheet material for the bimetallic support 4 can be used with high dimensional stability and sufficient support rigidity.

The handling leg 4a of the bimetal carrier 4, which is located in the region of the free end 3b of the bimetal 3 and is directed outwards there, is held on the end face in a housing opening or contour 13 and is supported there. The handling leg 4a is formed deformable. This is the bimetallic adjustment and thus for adjusting the distance A between the free end 3b of the bimetal 3 and the release lever 6 by means of a (not shown) handling tool of the handling leg 4a of the bimetallic support 4 twisted and thus the bimetal 4 bent or deformed. As a result, the position of the bimetal 3 for adjusting the distance A changes accordingly.

Thus, when the handling leg 4a is twisted, the bimetal 3 and thus its free end or bimetal tip 3b are rotated in the release direction D. The adjusting device is essentially formed by the position-fixed handling leg 4b of the bimetallic support 4 with the bimetal 3 held thereon.

FIGS. 5a to 5d show different geometries of the handling leg 4a of the bimetal carrier 4. While this T-shaped handling leg 4a according to FIG. 5c can in principle be formed from solid material, passage openings 23 in the handling leg 4a and thus in the adjustment region are expediently along the leg longitudinal axis 14 of the bimetal carrier 4 introduced. These passage openings 23 may be designed as elongated holes or as rectangular openings according to FIGS. 5b and 5d. However, a number of circular bores 23 according to FIG. 5a are advantageous. In fact, with this geometry, a particularly favorable ratio between the angle of rotation and the change in length of the handling leg 4a can be realized. As a result, the desired goal is achieved to a particularly high degree to allow for a relatively large angle of rotation and a small change in length, a sensitive and accurate adjustment.

In the embodiment of the adjusting device according to Figures 6 and 7 of the handling leg 4a is provided with a nose-like contour 15, which can be guided along an arcuate housing and thus fixed counter contour 16. In this embodiment, the adjustment and thus the adjustment of the distance A takes place by bending the handling leg 4a in the direction of the arrow 17. In this case, the handling leg 4a moves as it slides along the nose-like contour 15 along the arcuate stationary counter contour 16 in the direction of arrow 18, so that the bimetallic tip 3b in turn moves in the triggering direction D. The length of the symbolized by the arrow 17 movement path of the handling leg 4a depends on the slope of the arcuate stationary counter contour 16.

In the embodiment of the bimetallic support 4 according to FIGS. 8 and 9, the handling leg 4a is in turn bent inwards and in turn is bent to form a first bending / bending point 19 '. The buckling / bending point 19 'is - as well as the bending point 8 - formed by a hole or punching in the sheet material of the bimetal 4. On the free end, the handling leg 4a is guided in a housing receptacle or rotary opening 20 which is effective as a rotary contour and which is provided in a suitably positioned housing contour in the form of a dome-shaped housing structure 21. At this lying within the rotational opening 20 free end of the handling leg 4a engages the actuating tool for Bimetalljustierung.

In these embodiments, by twisting or twisting the handling leg 4a in the direction of the illustrated double arrow 22, the bimetallic support 4 is in turn bent or deformed and changed the position of the bimetal 3 for adjusting the distance A. In the embodiment according to FIG. 8, a roll-up-like rotation of the handling leg 4a takes place around an axis running perpendicular to the plane of the drawing.

In the embodiment according to FIG. 9, the handling leg 4a is twisted about its leg transverse axis. In this case, in the region of the first bending / bending point 19 'and freiendseitig held or positionally fixed handling leg 4a by means of a fork-shaped twisting or handling tool 24 is twisted or twisted, which is used for this purpose in the rotation or adjustment hole 20 and rotated in the direction of arrow 22. Again, upon rotation of the handling leg 4a in the illustrated arrow direction 22, the bimetal tip or the free end 3b of the bimetal 3 is rotated in the triggering direction D, thereby performing the bimetallic adjustment. In these embodiments, the adjusting device is essentially formed by the bimetallic support 4 with the bimetal 3 held thereon and the rotary opening 20 in the housing attachment 21 which acts as an adjustment contour.

In the embodiment of the thermal release according to FIG. 10, the bimetal 3 is adjusted by a kind of bending buckling of the handling leg 4a of the bimetallic support 4 in the direction of the deformation arrow 22 '. In this case, the free end 4a 'of the handling leg 4a is held in a housing opening 20', so that in the central region 4a '' of the handling leg 4a this can be buckled or folded. Here, too, in a deformation of the handling leg 4a in the illustrated arrow direction 22 ', the bimetallic point or the free end 3b of the bimetal 3 in the release direction D moved and thereby performed the bimetallic adjustment.

Furthermore, FIG. 11 shows an alternative embodiment in which the holding leg 4b of the bimetal carrier 4 is guided around a housing contour 25 to form a loop. Here, in the region of the blade vertex 26 of the bimetallic support 4, a predetermined bending point 27 is introduced into this. In this embodiment, the handling leg 4a is located on the front side in the transition region between the holding leg 4b and the fixing leg 4c and thereby in the vicinity of the bending point 8 of the bimetallic support 4 and is supported there. By turning or bending the handling leg 4a around the predetermined bending point 27 in the direction of arrow 22 ", the bimetallic tip or the free end 3b of the bimetal 3 is in turn rotated in the triggering direction D, thereby carrying out the bimetallic adjustment.

Figures 12 and 13 show an alternative embodiment of the thermal release, which differs on the one hand from the embodiment of the thermal release according to Figures 1 and 2 by the use of a setting means 28 in the form of an adjusting screw or alternatively in the form of a stepwise latching pin or the like , On the other hand, the adjustment by the adjusting means 28 handling leg 4a is arranged largely perpendicular to this. In addition, in the embodiment according to FIGS. 12 and 13, in contrast to the embodiment according to FIGS. 1 and 2, the bimetallic support 4 is bent outwards with the aid of a bending-promoting bore / punching 29 at the first bending / bending point 19 '. This is followed by forming a second, perforated by the bore / punch-29 Bent / bending point 19 '' of the bimetal 4 bent. The bending point 8 is formed in the same way as the buckling / bending points 19 ', 19''.

In the further course of the bimetallic carrier 4, beads 12 are likewise introduced into the holding limb 4b in the region of the steps S1 and S2, so that a relatively thin sheet material for the bimetal carrier 4 can be used with high dimensional stability and sufficient carrier rigidity. Corner beads 12 and bending / bending / bending points 8 or 19 ', 19' 'provided with bores / punched-out portions 29 can accordingly vary depending on the desired mode of operation, such as e.g. a partial stiffening or an automatic readjustment in the form of a buckling at predetermined bending points, the bimetal 4 are introduced specifically.

In the embodiments according to FIGS. 9 and 10 as well as 12 and 13, the mechanism for bimetallic adjustment advantageously also compensates for a practically unavoidable material-specific housing shrinkage. Typical materials are usually plastics, especially duro- or thermoplastics. A thermoset proves a particularly good thermal stability, with a thermoplastic is characterized by a finer design option. Thermosets which are preferably used are, on the one hand, urea resin molding compounds and, on the other hand, melamine resin molding compounds.

If the position of the release lever 6 changes in the direction of the free end 3b of the bimetal 3 due to such housing shrinkage, this housing shrinkage-depending on the embodiment of the thermal release-also brings about an approximation of the housing contours acting as an adjustment contour, in which the Bimetallic 4 partly on and / or rests. The thus introduced to the bimetallic 4 force causes an automatic buckling and / or bending of the buckling / bending points 19 ', 19''and possibly the bending point 8 such that the distance A remains constant. As a result, an unwanted premature release of the thermal release can be avoided. By a targeted change in the geometric relationship between the bending point 8 and the buckling / bending points 19 ', 19'', the tracking behavior of the bimetal 4 can be defined.

The occurring at low cost materials, possibly due to heat or radiation influences aging processes and the resulting material / housing shrinkages can thus be compensated in an easy way with ease. With the adjusting device according to the invention, a relatively large deformation with a relatively small change in length of the deformable for adjustment bimetal 4 is achieved. As a result, a particularly sensitive or fine adjustment of the bimetal 3 of a thermal release is possible. The adjusting device is also suitable for a cold adjustment, with additional adjusting elements, for example in the form of a screw or the like., Eliminated. As a result, a cost saving is achieved by additionally the bimetal 4 can be made on relatively simple tools.

In addition, inexpensive materials and in particular bimetal 3 different length can be used, which in turn leads to a significant cost savings. By means of this adjusting device, the actual adjustment process is reversible at least within limits. Furthermore, the adjustment process with open or closed device housing 2 is feasible. Also is at the same time robust storage of the bimetal 3, the adjusting device and thus the thermal release particularly insensitive to shock loads.

The invention explained above can be summarized as follows:

In order to specify a particularly cost-effective and easily adjustable adjusting device for a thermal release of a switching device 1, in particular a circuit breaker, it is provided that in the thermal release, with a bimetal 3 held stationary on a bimetal 4 bimetal 3 whose free end 3b spaced to a trigger lever 6 is and these increasingly acted upon in the release direction D due to thermal deformation, the distance A between the trigger lever 6 and the free end 3b of the bimetal 3 by deforming the bimetal 4 is adjustable.

Claims (15)

1. Adjustment apparatus for a thermal release for a switching device (1), having a bimetallic strip (3) which is held in a fixed position on a bimetallic strip mount (4) and whose free end (3b) is at a distance from a tripping lever (6) and applies force to this tripping lever (6) increasingly in the tripping direction (D) as a result of thermal deformation, with the distance (A) being adjustable by deformation of the bimetallic strip mount (4),
   the bimetallic strip mount (4) having a holding limb (4b) which runs at least approximately parallel to the bimetallic strip (3) and to which the bimetallic strip (3) is connected at its contact end (3a), characterized in that the bimetallic strip mount (4) also has a handling limb (4a) at the free end which runs transversely with respect to the holding limb (4b), in which case it is possible to adjust the distance (A) by twisting the handling limb (4a).
2. Adjustment apparatus according to Claim 1,
   characterized in that the holding limb (4b) is curved in the form of a step.
3. Adjustment apparatus according to Claim 1 or 2,
   characterized in that the distance (A) can additionally be adjusted by bending the holding limb (4b).
4. Adjustment apparatus according to one of Claims 1 to 3,
   characterized in that the handling limb (4a) and/or the holding limb (4b) are/is in the form of a perforated plate or perforated plates with a number of openings (23; 29) which are arranged one behind the other in the limb longitudinal direction (14).
5. Adjustment apparatus according to one of Claims 1 to 4,
   characterized in that the bimetallic strip mount (4) has an at least approximately U-shaped fixing limb (4c) which is adjacent to the holding limb (4b), via a bend (8).
6. Adjustment apparatus according to one of Claims 1 to 5,
   characterized in that the handling limb (4a) of the bimetallic strip mount (4) is fixed in position in a fixed-position opening (13; 20).
7. Adjustment apparatus according to one of Claims 1 to 6,
   characterized in that the handling limb (4a) is positioned in the area of the free end (3b) of the bimetallic strip (3).
8. Adjustment apparatus according to one of Claims 1 to 5,
   characterized in that the holding limb (4b) of the bimetallic strip mount (4) is shaped like a loop, and the handling limb (4a) is supported on the bimetallic strip mount (4).
9. Adjustment apparatus according to Claim 8,
   characterized in that a desired bending point (27) is formed in the area of the loop apex (26) of the bimetallic strip mount (4).
10. Adjustment apparatus according to one of Claims 1 to 9,
    characterized in that the distance (A) can be adjusted by automatic deformation of the handling limb (4a) and/or of the holding limb (4b) of the bimetallic strip mount (4).
11. Adjustment apparatus according to Claim 10,
    characterized in that the distance (A) can be adjusted by bending of the handling limb (4a) and/or of the holding limb (4b) of the bimetallic strip mount (4) as a result of housing shrinkage, at bending points and/or kinking/bending points (8 and 19', 19'', respectively) which can be predetermined.
12. Adjustment apparatus according to Claim 11,
    characterized in that the bending is produced by housing shrinkages and by the approximation, which results from this, of the housing contours (9, 13, 16, 21) which act as an adjustment contour and in which and/or on which the bimetallic strip mount (4) partially rests.
13. Adjustment apparatus according to one of Claims 1 to 12,
    characterized in that a hole/stamped-out region (29) is arranged at at least one position of the bimetallic strip mount (4), in particular in the area of the holding limb (4b) which is in the form of a step, in order to form a bending point and/or a kinking/bending point (8 or 19', 19'', respectively).
14. Switching device, in particular a line circuit breaker, having an adjustment apparatus according to one of Claims 1 to 13.
15. Switching device according to Claim 14,
    characterized by a housing (2) composed of urea and/or melamine resin moulding compound.

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