Patent Grant
7994442
This application claims priority under 35 U.S.C. ยง119 to EP Application 06405301.0 filed in Europe on Jul. 12, 2006, the entire contents of which are hereby incorporated by reference in their entireties.
The invention is directed to the field of high-voltage technology, particularly high-voltage switchgear in electric power distribution networks. It is based on an interrupter unit for a circuit breaker and a circuit breaker.
The invention is based on the related art as disclosed in the applicant's own European Patent No. EP 0 313 813 A1. In that document, a circuit breaker with a breaker drive is described, which moves the first arcing contact piece and also drives the opposing, second arcing contact piece via an auxiliary gear that is linked to the insulation nozzle. The auxiliary gear has two gearwheels, each of which cooperates with two toothed racks or cogging mechanisms arranged parallel to the axis of the circuit breaker. The first toothed racks are permanently connected to the insulation nozzle. The second toothed rack has two cogging mechanisms and is connected to the arcing contact pin. The gearwheels are rotated by the axial motion of the insulation nozzle and the first toothed racks, and in turn drive the second toothed rack axially in the opposite direction. The auxiliary gear comprises an assembly plate or mounting that accommodates the gearwheel bearings and is fixed to the external nominal current contact. The auxiliary gear further includes a guiding block, which accommodates the guide slide bearings for axial guidance of the arcing contact pin and is also secured to the external nominal current contact. The mounting and the guiding block constitute two separate assemblies, which must be inserted into the circuit breaker, aligned and mounted independently of one another in two separate assembly operations. Additionally, it must be ensured that the movements of the two first toothed racks are precisely synchronized, because the first toothed racks engage with cogging mechanisms that are arranged flush with each other on the same, second toothed rack, with the result that both are coupled in force-fit manner to the arcing contact pin. Accordingly, the first toothed racks must be adjusted so that they are flush with one another. This is achieved most simply by adjusting them so that they are assembled with their respective cogging mechanisms equidistant from the insulation nozzle.
A refinement of the circuit breaker with dual toothed rack drive is disclosed in the applicant's own European Patent No. EP 0 999 569 A1. The sliding contact arrangement comprises a sliding contact ring that is firmly fixed to the arcing contact pin and is supported on its outer side by the inner surface of the surrounding contact tube, and is guided in sliding manner along this tube. The sliding contact ring is connected to the arcing contact pin via radial spokes.
Although in EP 0 313 813 A1 and EP 0 999 569 A1 an auxiliary gear with only one gearwheel, with one driving rack and one driven rack is mentioned, they are associated with problems of one-sided loading, wear or tilting, which have not yet been solved. Accordingly, a mirror-symmetrical arrangement with two gearwheels and four toothed racks is presented as the preferred configuration, and is the only configuration that has been used for practical purposes to date.
A further variant of the circuit breaker, with dual toothed rack drive, is described in the applicant's own U.S. Pat. No. 5,478,980. The assembly plate for accommodating the gearwheels is mounted on the guiding block via axially extending pillars. The guiding block incorporates the guide slide bearings, and is itself fixed to the external nominal current contact. The lengths of the toothed racks are adjustable with adjusting screws. In this way, the driving toothed racks may be adjusted to be flush with one another more easily.
The object of the present invention is to suggest a simplified construction for a circuit breaker with dual movement of the arcing contacts.
The invention consists in an interrupter unit for an electrical circuit breaker, in particular a high-voltage circuit breaker, for power supply networks, wherein the circuit breaker has a central axis, an insulation nozzle for arc blowing, a first contact system, a second contact system, and a circuit breaker drive that drives the first contact system and also drives the second contact system via an auxiliary gear, wherein the auxiliary gear has holding means and guiding means for a toothed rack drive, wherein the auxiliary gear comprises a monoblock in which the holding means and guiding means for the toothed rack drive are integrated. The integral construction in one monoblock reduces the number of components and simplifies the assembly and adjustment of the auxiliary gear in the circuit breaker.
In an advantageous embodiment, a pusher guide slide bearing is recessed into the arcing contact piece that is driven by the auxiliary gear. In this way, the arcing contact piece may be prevented from tilting in a particular effective and durabe manner.
In a further advantageous embodiment, the toothed rack gear has exactly one gearwheel, exactly one first toothed rack for driving the gearwheel, and exactly one second toothed rack for moving the second arcing contact. Reducing the number to exactly one gearwheel, which cooperates with exactly one driving toothed rack and exactly one cogging mechanism in the arcing contact piece, enables a significantly simplified construction of the auxiliary gear without sacrificing any of the reliability of the circuit breaker drive.
In a further advantageous embodiment, a limit stop is provided for the arcing contact piece that is driven by the auxiliary gear. Accordingly, complicated adjustments need not be made to the toothed rack when the circuit breaker is equipped with the auxiliary gear.
Additional embodiments relate to design variants of the monoblock and its mounting in the circuit breaker, and to design variants of the toothed rack drive, and to an electrical circuit breaker having an arcing interrupter unit as described above, and having the advantages described above.
Additional embodiments, advantages, and applications of the invention will be evident from the following description and figures.
The drawings show schematically and in exemplary manner in:
In the figures, identical or equivalent parts are provided with identical or similar reference numbers.
According to the invention, the auxiliary gear 5 to 11 comprises a monoblock 5, in which holding means 5a and guiding means 5b for toothed rack drive 6 to 8 are constructively integrated. The monoblock represents a monolithic assembly, which may be fitted as a complete single-piece unit or may be equipped with elements before it is fitted as a complete unit in the breaker. Exemplary embodiments of such will be described in the following.
The monoblock 5 should comprise a holding means 5a, in which a bearing is provided for at least one cogwheel 6 of the toothed rack drive 6 . . . 8; and/or the monoblock 5 should comprise in its guiding means 5a one guide slide bearing 9, 11 and one sliding contact 10 for the arcing contact piece 3a that is driven by auxiliary gear 5 . . . 11; and/or the monoblock 5 should be connected in electrically conductive manner to the externally arranged nominal current contact 3b in order to draw current from the arcing contact piece 3a.
The monoblock 5 advantageously forms a single assembly unit 5, which may be inserted into the circuit breaker 1 completely as a single unit, and/or the monoblock 5 is constructed as a single-piece unit. In particular, the monoblock 5 may be a single-piece cast part 5.
In order to make installation of the monoblock 5 on circuit breaker 1 as simple as possible, only a single mounting fixture 5c, 5d is present. As is shown in the example, the monoblock 5 may have exactly one mounting flange 5c, which is attachable to exactly one mating flange 5d on the circuit breaker 1.
In an advantageous configuration, a pusher guide slide bearing 11 is recessed directly in the arcing contact piece 3a that is driven by the auxiliary gear 5 . . . 11. This reduces the danger of tilting even during single-sided driving, as will be described below. Alternatively or in addition, a fixed guide slide bearing 9 may be recessed in the guiding means 5b of the monoblock 5 for guiding the arcing contact piece 3b that is or may be driven by the auxiliary gear 5 . . . 11. This combination of the features of the guide slide bearing 9, 11, in particular the combination of a pusher guide slide bearing 11 in the rear part of the arcing contact piece 3a, which faces away from the arcing zone, with a fixed guide slide bearing 9 in the front part of the arcing contact piece 3a, which faces towards the arcing zone, may also be implemented regardless of the construction as a monoblock.
In a further advantageous configuration, the toothed rack gear 6 . . . 8 has exactly one gearwheel 6, exactly one first toothed rack 7 for driving the gearwheel 6, and exactly one second toothed rack 8 for moving the second arcing contact 3a. In such a case, adjustment screws are no longer needed to ensure that several driving toothed racks are adjusted to be flush with each other.
Insulation nozzle 4 is advantageously movable and serves for transmitting force from the circuit breaker drive to the auxiliary gear 5 . . . 11. The first toothed rack 7 is attached to the insulation nozzle 4. The first toothed rack 7 is preferably constructed such that it may be screwed into the insulation nozzle 4, with the axial distance D between its cogging 7b and the insulation nozzle 4 being adjustable. Moreover, adjusting screws on the first toothed rack 7 for adjusting the length of first toothed rack 7 should be absent. In fact, the length of the toothed rack need not be adjusted in the construction with only one toothed rack 7 either, provided precisely defined distances are maintained between the insulation nozzle 4 and the cogging 7b. This may be realized particularly easily in the construction of the monoblock.
For this purpose, in an advantageous embodiment, a limit stop 30a, 50a is provided for the arcing contact piece 3a that is driven by the auxiliary gear 5 . . . 11. This limit stop 30a, 50a may be created by providing a shoulder 30a (protruding or recessed) on the arcing contact piece 3a, which shoulder cooperates with an opposing shoulder 50a (protruding or recessed) on the monoblock 5 in such manner, that an end position is defined for the arcing contact piece 3a, when it is fully inserted, which end position corresponds to a desired, predeterminable distance to the opposing arcing contact piece 3b or to the insulation nozzle 4, respectively.
A further object of the invention is an electrical circuit breaker 1 for a power supply network with an interrupter unit as described above. The circuit breaker may, in particular, be a gas-blast circuit breaker or a self-blast circuit breaker; and/or a high-voltage circuit breaker 1 or a high-current circuit breaker, or generally a power circuit breaker; and/or a life tank circuit breaker, an encapsulated circuit breaker as dead tank breaker or for a gas-insulated switchgear assembly, or a hybrid circuit breaker.
Another object of the invention relates to a method for assembling the circuit breaker 1 with an interrupter unit as described previously. In this context, the insulation nozzle 4 is pre-assembled with the at least one toothed driving rack 7 in the circuit breaker 1. According to the invention, the following assembly steps are performed: (i) Inserting the arcing contact piece 3a that is driven by auxiliary gear 5 . . . 11 into the monoblock 5 as far as limit stop 30a, 50a; (ii) Inserting the monoblock 5 into the circuit breaker 1 until mounting fixtures 5c, 5d come in touch with one another; and (iii) using the mounting fixtures 5c, 5d to secure monoblock 5 inside the circuit breaker 1. The toothed rack transmission 6 . . . 8 may thus be adjusted and set particularly easily due to the construction as a monoblock.
| Number | Date | Country | Kind |
|---|---|---|---|
| 06405301 | Jul 2006 | EP | regional |
| Number | Name | Date | Kind |
|---|---|---|---|
| 5478980 | Freeman et al. | Dec 1995 | A |
| 5578806 | Hofbauer et al. | Nov 1996 | A |
| 6015960 | Girodet et al. | Jan 2000 | A |
| 20090008367 | Kriegel et al. | Jan 2009 | A1 |
| Number | Date | Country |
|---|---|---|
| 0 313 813 | May 1989 | EP |
| 0 696 040 | Feb 1996 | EP |
| 0 785 562 | Jul 1997 | EP |
| 0 907 195 | Apr 1999 | EP |
| 0 999 569 | May 2000 | EP |
| 9912177 | Mar 1999 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 20080047813 A1 | Feb 2008 | US |
