EP2460167B1 - Electric switchgear having a snap-action drive - Google Patents

Description

The invention relates to an electrical switching device, in particular a load-disconnector, with a jump drive according to the preamble of claim 1. Such a switching device is for example from the DE 28 50 761 C3 known.

Electrical switching devices often require an indirectly acting drive to ensure that switching operations always take place independently of external influences with the same and sufficient speed. This is realized, for example, by jump drives, which comprise a rechargeable energy store, which enables a sudden switching.

This is especially true for load disconnectors used to switch high voltage circuits in the industrial and marine systems. In marine systems, for example, load disconnectors for DC voltages from 450 V to 900 V and switching currents up to 400 A are used. During the switching operations of such a load disconnector arise due to the high switching currents and switching voltages, arcs, which lead to a gradual burn-off of the contacts and thus can wear the switching devices. To minimize burnup of the contacts, the resulting arcing must be as low as possible. This can be achieved by short switching times. In order to reduce the switching times of such load disconnectors, the switching kinematics within the load disconnectors are provided with stepper drives. The jump drive increases the speed of movement that an operator applies to a switching element in the region of a switching point. This is usually done by spring elements in jump drive.

From the DE 10 2006 008 338 B3 For example, an on-load tap changer with energy storage is known in which the energy storage device is used for uninterrupted switching between different winding taps of a tapped transformer under load. The energy accumulator has one or more compression springs, which are tensioned at the beginning of a changeover.

From the EP 1 535 791 A1 Another load switch is known in which compression springs are used.

One from the DE 28 50 761 C3 known jump drive for an electrical switching device with a switching shaft comprises a compression spring whose spring force causes a jump-like movement of the switching shaft via a rotatably mounted on the switching shaft transmission member. A tensioning device for the spring is also arranged rotatably on the shift shaft and rotates in its rotational movement after a freewheel movement with the transmission member. The transmission member is designed as a U-shaped driver part in which a first and a second clamping pin sits. The tensioning device comprises a tensioning pulley and an actuating lever which is connected to the tensioning pulley. The actuating lever has a circular recess in which moves the first dowel pin, which also establishes a connection with the compression spring. When a switch-off of the switching device, the first dowel pin is taken with the U-fömigen driver part on the operating lever while the spring tensioned. After reaching a dead center, the tensioned spring is released and frictionally a seated on the shift shaft dowel pin moves through the second dowel pin, so that the shift shaft is rotated.

Based on this, it is an object of the present invention to provide a switching device with a jump drive, which is characterized by a simple structural design, small number of components and a small footprint and thus in particular for use in mobile systems with limited space, such as. in ships, is suitable.

The solution of this object is achieved by an electrical switching device according to claim 1. Advantageous embodiments are the subject of the dependent claims.

In a switching device according to the invention with a switching shaft and with a jump drive with a spring element which causes a sudden movement of the switching shaft, comprising Jump drive a buckling lever with a first and a second arm, wherein the first arm at its end facing away from the second arm is rotatably connected to the switching shaft and the second arm is rotatably mounted at its end facing away from the first arm stationary relative to the shift shaft, and wherein the second arm comprises two sub-arms, between which the spring element is arranged. By a rotation of the switching shaft, the lever can be moved from a tilted position in which the spring element is not stretched in an extended position, wherein the spring element is tensioned. When the extended position is exceeded, the spring element can then relax and then abruptly moves the rocker arm and the switching shaft connected thereto, as a result of which a rapid switching operation in the switching device is effected. The articulated lever serves both to tension the spring element and as a transmission member for transmitting the spring force to the shift shaft. The solution according to the invention is thus characterized by only a small number of components and a small footprint. In an articulated lever is a structurally simple component, so that the solution according to the invention is also characterized by a structurally simple structure. Another advantage is that the jump drive acts in both switching directions, ie both for a switch-off and for a switch-on. As a result, components can also be saved. In addition, the jump drive can be operated from multiple sides, which increases the flexibility in terms of the installation location of the switching device and its operation.

Preferably, a holder for the spring element is formed on the two partial arms. The spring element can thus be reliably held in a correct position between the two partial arms.

According to an advantageous embodiment, the spring element comprises one or more compression springs, since compression springs are characterized by a comparatively high reliability.

To further increase the reliability, the spring element may also comprise two concentric pressure springs arranged. Thus, even if one of the two springs fails, the function of the switching device can be maintained. The concentric arrangement also leads to a uniform spring load and a small footprint.

A particularly high compactness and shock resistance of the switching device and mechanical stability of the jump drive is possible because the switching device has a base plate in or on which the switching shaft and the second arm of the articulated lever are rotatably mounted.

For manual operation, the switching device advantageously on a manually operable control element and a mechanism for converting a movement of the operating element in a rotational movement of the shift shaft.

According to a particularly advantageous embodiment, the control element comprises an operating lever which is rotatably connected to a rotatable disc through which one end of a first actuating lever is guided, which in turn leads with its other end a second operating lever which is non-rotatably connected to the switching shaft.

FIG 1

ein Teilschnittbild eines erfindungsgemäßen elektrischen Schaltgerätes in Seitenansicht,

FIG 2

eine Detaildarstellung des Sprungantriebs des Schaltgerätes von FIG 1 in einer ersten Endstellung,

FIG 3

eine Detaildarstellung des Sprungantriebs des Schaltgerätes von FIG 1 in einer Mittelstellung und

FIG 4

eine Detaildarstellung des Sprungantriebs des Schaltgerätes von FIG 1 in einer zweiten Endstellung.

The invention and further advantageous embodiments of the invention according to features of the subclaims are explained in more detail below with reference to exemplary embodiments in the figures; show in it:

FIG. 1

a partial sectional view of an electrical switching device according to the invention in side view,

FIG. 2

a detailed representation of the jump drive of the switching device of FIG. 1 in a first end position,

FIG. 3

a detailed representation of the jump drive of the switching device of FIG. 1 in a middle position and

FIG. 4

a detailed representation of the jump drive of the switching device of FIG. 1 in a second end position.

An only hinted at FIG. 1 illustrated switching device in the form of a load disconnector 1 includes a switching shaft 2, a jump drive 3 for the switching shaft 2 and a manual control in the form of a stirrup drive. 4

In load disconnectors usually cam switching elements are used as switching units. At voltages higher than 24V, the cam switching elements are equipped with arcing chambers to extinguish the arc. The load disconnector 2 therefore has cam switching elements and arcing chambers, which are not shown in more detail. In addition, the switching shaft 2 cam not shown for actuating the cam switching elements.

The switching shaft 2 is rotatably supported on a base plate 5 of the load disconnector 1 via a shaft bearing. On the base plate 5, the cam switching elements, the arc chambers and electrical connection components are attached (not shown).

In the stirrup drive 4 is a manual drive, ie the operation is done manually, for example via an operating lever 6, and not via additional drive units. An actuating mechanism 7 is used to convert a movement of an operating lever 6 of the stirrup drive 4 in a rotational movement of the shift shaft 2. The operating lever 6 is rotatably connected thereto with a rotatable disc 20 through which one end of a first operating lever 21 is guided, with his other End again a second operating lever 22 leads, which is rotatably connected to the switching shaft 2. The first operating lever 21 has a slot 23 for guiding the second operating lever 22. In this a bolt 24 is guided, which sits on the second operating lever 22.

Upon actuation of the operating lever 6, the disc 20 is rotated and thus the first actuating lever 21 is guided vertically downward in a substantially translational movement. By this movement, the bolt 24 is pressed into the upper end position of the elongated hole 23 and positively entrained by the first actuating lever 21. The bolt 24 then guides the second operating lever 22 such that it rotates the switching shaft 2.

As in detail in the FIGS. 2 to 4 illustrated, the jump drive 3 includes a buckling lever 8 with a first arm 9 and a second arm 10, which are connected to each other via a hinge 11. The first arm 9 is rotatably connected at its second arm 10 and the hinge 11 facing away from the switching shaft 2.

The second arm 10 is rotatably mounted at its end facing away from the first arm 9 and the hinge 11 by a bolt 14 in a holder 13. The holder 13 is screwed tightly to the base plate 5. The second arm 10 is thus fixedly mounted with respect to the shift shaft 2.

The second arm 10 comprises two partial arms 10a, 10b, between which a spring element 15 is arranged. The spring element 15 comprises two concentric cylindrical pressure springs 15a, 15b, whose longitudinal axis extends in the direction of the longitudinal axis of the second arm 10.

Each of the partial arms 10a, 10b has at its respective side facing the springs 15a, 15b a holder 12 for the springs 15a, 15b. This holder 12 comprises a flat support surface 16 for the end faces of the spring 15 a, 15 b and elevations 17, 18. The support surface 16 is bounded radially outwardly by an annular elevation 17, at which the outer compression spring 15a is applied and thus always kept in the correct position. On the other hand, the bearing surface 16 is bounded radially inwardly by a cylindrical elevation 18, on which the inner compression spring 15b is seated and thus likewise always held in the correct position. As it turns out, these measures are sufficient for correct positioning and guidance of the position of the springs in most cases.

In an alternative embodiment, not shown, a bolt may be arranged centrally within the springs for guiding the springs 15a, 15b. The bolt head is then advantageous in a socket, which is screwed in the region of the spring support surface 16 of the hinge 11 facing first part of arm 10a with this arm 10a. In the region of the spring support surface 16 of the joint 11 facing away from the partial arm 10 b is then preferably a gap through which the bolt is fixed by means of a lock washer.

The articulated lever 8 and the second operating lever 22, both of which are non-rotatably connected to the switching shaft 2, may be formed as a separate lever. To reduce the number of components and the space requirement form the two levers 8, 22 - as in 1 - 4 shown - but a straight double lever, ie, the second operating lever 22 and the first arm 9 of the articulated lever 8 are connected in a line, wherein between the two levers, the shift shaft 2 is arranged.

The articulated lever 8 is of an in FIG. 2 shown in the first end position in which he is bent over a in FIG. 3 shown stretched position in an in FIG. 4 shown second end position in which he is also kinked, and vice versa.

The fixation of the two in FIG. 2 and 4 shown end positions can be done by stops not shown, which are arranged on the shift shaft 2.

The lengths of the first arm 9, the lengths of the first and second partial arms 10a, 10b, the dimensioning of the springs 15a, 15b and the distance between the switching shaft 2 and the bolt 14 are matched to one another such that in the in FIG. 3 shown extended position of the articulated lever 8 between the first part of arm 10a and the second part of arm 10b enough space for the compressed compression springs 15a, 15b is present.

Through the slot 23 in the first operating lever 21 entrainment of the first operating lever 21 and thus of the operating element 6 is avoided in a switching of the jump drive 3. After such switching through the operating lever 6 of the stirrup drive 4 is then manually brought by an operator in its respective end position.

• FIG 2 zeigt die Schaltwelle 2 in einer ersten Schaltstellung, beispielsweise einer Einschaltstellung des Schaltgerätes 1. Der Knickhebel 8 befindet sich dabei in einer ersten Endlage. Die beiden Arme 9, 10 des Kipphebels 8 sind dabei zueinander gekippt.

In the following, the operation of the jump drive 3 based on FIGS. 2 to 4 explains:

• FIG. 2 shows the switching shaft 2 in a first switching position, for example, a closed position of the switching device 1. The articulated lever 8 is in a first end position. The two arms 9, 10 of the rocker arm 8 are tilted to each other.

If an operator manually moves the control lever 6, then the control shaft 2 is rotated counterclockwise via the first operating lever 21 and the second operating lever 22 and thereby the rocker arm 8 from its in FIG. 2 shown end position in an in FIG. 3 shown expanded position in which the rocker arm 8 is fully extended. During this movement, the springs 15a, 15b are compressed or tensioned. The holder 13 serves as an abutment for the second arm 10 of the articulated lever 8 during compression of the springs 15a, 15b.

Upon release of the operating lever 6 before reaching the extended position, the springs 15a, 15b push the rocker arm 8 and thus also the shift shaft 2 clockwise back into the in FIG. 2 shown starting position back.

When the extended position is exceeded, the springs 15a, 15b relax and move the rocker arm 8 and thus also the selector shaft 2 abruptly counterclockwise to the in FIG. 4 As a result, the spring force is dimensioned such that it reaches a switching force required for switching the contacts of the switching device 1.

By a movement of the kick lever in the reverse direction, ie from the in FIG. 4 shown end position in the in FIG. 2 shown end position, a switch-on of the switching device is possible in the same way.

As can be seen, only very few different components are needed for the jump drive 3. The jump drive 3 has a structurally very simple structure and is characterized, in particular in combination with a stirrup drive, by a high reliability and shock resistance at the same time high compactness and small footprint. A great advantage is also that the stirrup drive 4 can be arranged below the base plate 5 instead of above the base plate 5, wherein the first actuating lever 21 is then coupled from below with the second actuating lever 22. This results in a high degree of flexibility with regard to the installation location and the operation of the switching device, which is particularly suitable for use in mobile systems such as e.g. in ships is of great advantage.

Claims (8)

1. Electrical switchgear (1), in particular a load disconnector having a breaker shaft (2) and a snap-action operating mechanism (3) with a spring element (15) which produces a snap-action type movement of the breaker shaft (2),
   the snap-action operating mechanism (3) containing an articulated lever (8) with a first and a second arm (9, 10), it being possible for the first arm (9) to be connected to the breaker shaft (2) in a torsionally-rigid manner by its end which faces away from the second arm (10) and for the second arm (10) to be supported in a rotatable manner by its end facing away from the first arm (9) in a stationary position with respect to the breaker shaft (2), and it being possible for the second arm (10) to include two sub-arms (10a, 10b) between which the spring element (15) is mounted, characterised in that a second actuating lever (22) and the first arm (9) of the articulated lever (8) are connected to each other in a line, the breaker shaft (2) being disposed between the two levers.
2. Electrical switchgear (1) according to claim 1, characterised in that a retainer (12) for the spring element (15) is constructed at the two sub-arms (10a, 10b).
3. Electrical switchgear (1) according to one of the preceding claims,
   characterised in that the spring element (15) contains one or a plurality of compression springs (15a and 15b).
4. Electrical switchgear (1) according to one of the preceding claims,
   characterised in that the spring element (15) contains two concentrically-disposed compression springs (15a, 15b).
5. Electrical switchgear (1) according to one of the preceding claims,
   characterised by a baseplate (6) in or on which the breaker shaft (2) and the second arm (10) of the articulated lever (8) are supported in a rotatable manner.
6. Electrical switchgear (1) according to one of the preceding claims,
   characterised by a manually-operated operator control element and a mechanism (7) for translating a movement of the operator control element (6) into a rotational movement of the breaker shaft (2).
7. Electrical switchgear (1) according to claim 6,
   characterised in that the operator control element contains an operator control lever (6) that is connected to a rotatable disk (20) in a torsionally-rigid manner, said disk controlling one end of a first actuating lever(21), whose other end controls the second actuating lever (22) which is connected to the breaker shaft (2) in a torsionally-rigid manner.
8. Electrical switchgear (1) according to claim 7,
   characterised in that the first actuating lever (21) has a slot (23) for controlling the second actuating lever (22).

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