GB1585352A - Apparatus for causing stepwise switching of tap switches of a tapped transformer - Google Patents

Description

(54) APPARATUS FOR CAUSING STEPWISE SWITCHING OF TAP SWITCHES OF A TAPPED TRANSFORMER (71) We MASCHINENFABRIK REIN HAUSEN GEBRijDER SCHEUBECK GMBH & CO KG, of Falkensteinstrasse 8, 8400 Regensburg 12, Federal Republic of Germany, a Kommanditgesellschaft organized under the laws of the Federal Republic of Germany do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to an apparatus for causing stepwise switching of tap switches of a tapped transformer.

Known apparatus for this purpose comprise force storage drives (see, for example, German (Fed. Rep.) Patent Specification No. 1947 427). In known force storage drives, it is difficult to attain a uniformly high speed of the Geneva wheel. For this reason the known force storage drive has been equipped with a special gear with varying course of turning moment. A gear of that kind is, however, very expensive. Furthermore, a force storage in the known construction cannot be constructed co-axially with the switching shaft.

According to the present invention there is provided an apparatus for causing stepwise switching of tap switches of a tapped transformer, the apparatus comprising a Geneva wheel provided with a plurality of notches each associated with a respective switching step, a first rocker carrying at one end thereof a Geneva dog which is arranged to engage in the notches in succession, the other end of the rocker being guided in an elongate opening arranged in a fixed location and extending radially of the Geneva wheel, an eccentric member arranged to move the rocker in such a manner that the Geneva dog describes an elliptical path on each revolution of the eccentric member, each switching step of the Geneva wheel corresponding to rotation of the eccentric member through substantially 1800, crank means arranged to drive the eccentric member, resilient means articulated to the crank means to provide an overcentre action, rotary drive means operable to drive the crank means to thereby so tension the resilient means for each switching step to be executed that the resilient means after passing its dead centre position drives the crank means independently of the drive means to cause the eccentric member to rotate through said substantially 1800, and a second rocker arranged to be pivotable about a fixed axis and carrying a locking member which is arranged to engage in successive ones of the notches to lock the Geneva wheel between switching steps, the second rocker being so coupled to the first rocker that during each switching step the locking member leaves the notch in which it was engaged.

Advantageously, an apparatus embodying the invention requires no gearing, and the pivotable parts thereof may be constructed co-axially together with the Geneva wheel and the switch shaft. A uniform course of motion may be attained in the stepwise motion of the Geneva wheel, since the part of the elliptical path decisive for the motion of the Geneva wheel practically runs transversely to the Geneva notch.

Advantageously, a secure, play-free latching of the Geneva wheel in the rest positions as well as during the winding-up process is attained.

In one embodiment of the invention, the eccentric member may be, advantageously, constructed as a circularly round plate, at the periphery of which the first rocker is rotatably journalled. The eccentric plate may then be provided with two cogs, against which the crank means comes to bear in accordance with its rotational direction. With constant rotational direction, the crank means then always lies against the same cog so that the crank means entrains the eccentric plate already during the winding-up operation, whereby the Geneva dog describes the outer half path of the ellipse. Conversely, when the rotational direction changes, then the crank means runs idly during the winding-up operation and lays itself against the other cog of the eccentric plate only shortly before attainment of the dead centre position.

The invention will now be more particularly described, by way of example, with reference to the accompanying drawings in which: Figure 1 shows a plan view of an apparatus embodying the invention with its housing cut open, and Figure 2 shows a longitudinal section of the apparatus of Figure 1.

Referring now to the drawings, apparatus embodying the invention is arranged on a base plate 1 within a housing 2 and comprises a driving crank 3 pivotable through 360 degrees, a spring 4, which is connected, by a spigot 5, to a driven crank 6, an eccentric plate 7 journalled co-axially with the driven crank 6, a rocker 8, which is rotatably journalled at the outer periphery of the eccentric plate 7 and at its free end carries a Geneva dog 9, a Geneva wheel 10, and a second rocker 11, which is coupled with the first rocker 8 and which possesses a blocking pin 12. The rotatable parts 3, 6, 7 and 10 of the force storage drive are co-axially arranged and the shaft 30 can be coupled directly, likewise coaxially with a switch shaft (not shown).

The driving crank 3 is turned in counterclockwise sense through 360" starting from the setting shown in the drawings by means of a shaft spigot 13 through a hand crank (not shown) or through a likewise electrical motor (not shown). The crank in this case at first runs idly through about 1800.

Thereafter, it impinges on the spigot 5, which is connected with the driven crank 6 and on which the spring 4 is hooked in by means of the tension strap 22. Thus, the driven crank 6 is entrained in pivotal direction so that the spring 4, which is fastened by its other end at a bracket 31, is tensioned. Furthermore, the eccentric plate 7 is entrained through the prolongation 14 of the spigot 5, which bears against the cog 15 of the eccentric plate 7. The eccentric plate 7 thereby in its turn actuates the rocker 8, which as already explained, is journalled around the eccentric plate 7.

This rocker 8 is now guided at its one end by means of the bolt 16 in an elongate hole 17, which is arranged radially to the Geneva wheel 10 in the base plate. Hereby, the Geneva dog 9, arranged at the free end of the rocker 8, describes the path of an ellipse. That is to say, this Geneva dog 9 leaves the Geneva notch 18 during the winding-up operation and moves on the elliptical path in dashed lines to the adjacent Geneva notch 19. The base plate 1 is provided with a recess 32 for this.

The drive crank 3 overcomes the dead centre position of the spring 4 shortly before completion of the 360" rotation so that the spring 4 can then relieve itself automatically. The spring 4 thereby automatically draws the driven crank 6 by means of the tension strap 22 into the basic setting as it is shown in the drawings. Since the prolongation 14 of the spigot 5 during this operation just as before bears against the cog 15 of the eccentric plate, the eccentric plate is entrained also in this case so that the rocker 8 must adapt itself to the respective position of the eccentric plate 7. In this case, the Geneva dog 9 describes the second part of the elliptical path, whereby the Geneva wheel 10 is moved on through one switching step.

During this operation, a blocking pin 12, which in the rest position lies in a Geneva notch 20, comes out of this Geneva notch at the right time. This occurs with the aid of the second rocker 11, which is journalled around a locally fixed spigot 21 and which is articulatedly connected with the bolt 16 of the first rocker 8. When this bolt 16 now slides upwards by reason of the motion of the rocker 8, then it entrains the second rocker 11 so that the blocking pin 12, which extends through a recess 29 in the base plate 1 through this, leaves the Geneva notch 20. As soon as the rocker 8 has then again attained its basic setting, the rocker 11 also again assumes the shown position, whereby the blocking pin 12 again drops into a Geneva notch. When thereagainst the rocker 8 is brought over to the next Geneva notch 19 with the aid of the eccentric plate during the winding-up operation, the Geneva dog 9 thus runs on the lower part of its elliptical path, then also the second rocker 11 is moved downwardly hereby so that the blocking pin 12 can penetrate only still further into the Geneva notch, whereby a secure location of the Geneva wheel is attained during this operation. This secure location of the Geneva wheel is present also in the basic setting, since the Geneva dog 9 as well as also the blocking pin 12 each lie in a Geneva notch. This accurate secure location of the Geneva wheel in the basic setting as well as also in the preparatory phase of the next switching step is important, since an independent motion of the Geneva wheel must be excluded because of the relatively small switching angle from switch position to switch position.

The herebefore described operation repeats itself in like manner from switching step to switching step insofar as the rotational direction of the driving crank 3 remains maintained. When the rotational direction is now however changed, again starting from the basic setting shown the driving crank 3 is thus now moved in clockwise sense, then it at first again runs idly through about 1800 before it can entrain the spigot 5 of the driven crank 6.

Then, the winding-up operation of the spring 4, which is hooked by the tension strap 22 on the spigot 5, sets in. In this case, however also the prolongation 14 of the spigot 5 at first runs idly so that the rocker 8 at first does not move. The Geneva dog 9 thus remains in the setting shown during the winding-up operation.

The spigot 5 impinges on the cog 23 of the eccentric plate 7 only shortly before attainment of the lower dead centre position and now entrains this. The Geneva dog is hereby moved further into the notch 18.

On overcoming the dead centre position, the spring 4 then again draws the driven crank 6 into the basic setting, while the prolongation 14 of the spigot 5 of course remains bearing against the cog 23 of the eccentric plate 7. That is to say, the rocker 8 is in this case so moved that the Geneva dog 9 moves the Geneva wheel 10 starting from the drawn position through one step in the other direction. The aforedescribed elliptical path is then again run through by the Geneva dog 9 only during the next switching step in the same direction, because the eccentric plate 7 is now disposed in a position, which is in mirror image to the drawn position and the spigot 5 from the start bears against the cog 23.

As is apparent from the elliptical path of the Geneva dog, a switching course at uniform switching speed can be attained from the start with the apparatus embodying the invention because from the instant, when the Geneva dog 9 starts to drive the Geneva wheel 10, it moves already on the substantially flat part of the curve of the ellipse. Hereby, a favourable force transmission is made possible. Insofar as it is required to let the switching operation proceed with a high initial force, the force storage spring 4 can be augmented by an additional spring 24. This additional spring 24 is hooked by an individual strap 25, which possesses a groove 26, onto a bolt 27, which in turn is connected through a connecting strap 28 with the tension strap 22. The groove 26 has the effect that the additional spring 24 is tensioned only in the last part of the tensioning process and thus also becomes effective only at the start of the relieving process. Hereby, a high initial acceleration may be attained.

WHAT WE CLAIM IS:- 1. Apparatus for causing stepwise switching of tap switches of a tapped transformer, the apparatus comprising a Geneva wheel provided with a plurality of notches each associated with a respective switching step, a first rocker carrying at one end thereof a Geneva dog which is arranged to engage in the notches in succession, the other end of the rocker being guided in an elongate opening arranged in a fixed location and extending radially of the Geneva wheel, an eccentric member arranged to move the rocker in such a manner that the Geneva dog describes an elliptical path on each revolution of the eccentric member, each switching step of the Geneva wheel corresponding to rotation of the eccentric member through substantially 1800, crank means arranged to drive the eccentric member, resilient means articulated to the crank means to provide an overcentre action, rotary drive means operable to drive the crank means to thereby so tension the resilient means for each switching step to be executed that the resilient means after passing its dead centre position drives the crank means independently of the drive means to cause the eccentric member to rotate through said substantially 1800, and a second rocker arranged to be pivotable about a fixed axis and carrying a locking member which is arranged to engage in successive ones of the notches to lock the Geneva wheel between switching steps, the second rocker being so coupled to the first rocker that during each switching step the locking member leaves the notch in which it was engaged.

2. Apparatus as claimed in claim 1, wherein the eccentric member comprises a substantially circular plate provided with a respective cog member for each rotational direction, each cog member being engageable by the crank means and the first rocker being rotatably mounted at the periphery of the plate.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (2)

**WARNING** start of CLMS field may overlap end of DESC **. driving crank 3 is thus now moved in clockwise sense, then it at first again runs idly through about 1800 before it can entrain the spigot 5 of the driven crank 6. Then, the winding-up operation of the spring 4, which is hooked by the tension strap 22 on the spigot 5, sets in. In this case, however also the prolongation 14 of the spigot 5 at first runs idly so that the rocker 8 at first does not move. The Geneva dog 9 thus remains in the setting shown during the winding-up operation. The spigot 5 impinges on the cog 23 of the eccentric plate 7 only shortly before attainment of the lower dead centre position and now entrains this. The Geneva dog is hereby moved further into the notch 18. On overcoming the dead centre position, the spring 4 then again draws the driven crank 6 into the basic setting, while the prolongation 14 of the spigot 5 of course remains bearing against the cog 23 of the eccentric plate 7. That is to say, the rocker 8 is in this case so moved that the Geneva dog 9 moves the Geneva wheel 10 starting from the drawn position through one step in the other direction. The aforedescribed elliptical path is then again run through by the Geneva dog 9 only during the next switching step in the same direction, because the eccentric plate 7 is now disposed in a position, which is in mirror image to the drawn position and the spigot 5 from the start bears against the cog 23. As is apparent from the elliptical path of the Geneva dog, a switching course at uniform switching speed can be attained from the start with the apparatus embodying the invention because from the instant, when the Geneva dog 9 starts to drive the Geneva wheel 10, it moves already on the substantially flat part of the curve of the ellipse. Hereby, a favourable force transmission is made possible. Insofar as it is required to let the switching operation proceed with a high initial force, the force storage spring 4 can be augmented by an additional spring 24. This additional spring 24 is hooked by an individual strap 25, which possesses a groove 26, onto a bolt 27, which in turn is connected through a connecting strap 28 with the tension strap 22. The groove 26 has the effect that the additional spring 24 is tensioned only in the last part of the tensioning process and thus also becomes effective only at the start of the relieving process. Hereby, a high initial acceleration may be attained. WHAT WE CLAIM IS:-

1. Apparatus for causing stepwise switching of tap switches of a tapped transformer, the apparatus comprising a Geneva wheel provided with a plurality of notches each associated with a respective switching step, a first rocker carrying at one end thereof a Geneva dog which is arranged to engage in the notches in succession, the other end of the rocker being guided in an elongate opening arranged in a fixed location and extending radially of the Geneva wheel, an eccentric member arranged to move the rocker in such a manner that the Geneva dog describes an elliptical path on each revolution of the eccentric member, each switching step of the Geneva wheel corresponding to rotation of the eccentric member through substantially 1800, crank means arranged to drive the eccentric member, resilient means articulated to the crank means to provide an overcentre action, rotary drive means operable to drive the crank means to thereby so tension the resilient means for each switching step to be executed that the resilient means after passing its dead centre position drives the crank means independently of the drive means to cause the eccentric member to rotate through said substantially 1800, and a second rocker arranged to be pivotable about a fixed axis and carrying a locking member which is arranged to engage in successive ones of the notches to lock the Geneva wheel between switching steps, the second rocker being so coupled to the first rocker that during each switching step the locking member leaves the notch in which it was engaged.

2. Apparatus as claimed in claim 1, wherein the eccentric member comprises a substantially circular plate provided with a respective cog member for each rotational direction, each cog member being engageable by the crank means and the first rocker being rotatably mounted at the periphery of the plate.