Title of Invention

ENERGY ACCUMULATOR

Abstract

The invention relates to an energy store for a load tap changer with a longitudinally movable lifting carriage and an also longitudinally movable snap-action carriage which follows the movement of the lifting carriage after being triggered and whose longitudinal movement is converted into a rotary movement of an output shaft that actuates the load tap changer. In order to do so, two rolls which are guided in an especially geometrically designed guide rail are disposed on the snap-action carriage. Only one of the two rolls is positively guided in the guide rail during the first part of each movement of the snap-action carriage while the other roll can be moved freely. The second roll that could previously be moved freely is then positively guided during the second part of the movement while the roll which was previously guided can be moved freely. The roll which was initially guided is positively guided once again during the third part of the movement.

Full Text

Energy Accumulator The invention relates to a force store for an on-load tap changer. On-load tap changers serve for uninterrupted switching over between different winding taps of a tapped transformer under load. Since this switching over usually takes place abruptly, on-load tap changers usually have a force store. Such a force store is already known from DE-PS 19 56 369 as well as DE-PS 28 06 282. At the beginning of each actuation of the on-load tap changer the force store is pulled up, i.e. stressed, by the drive shaft of the tap changer. The known force store substantially consists of a pull-up carriage and a jump can'iage, between which force storage springs are arranged as energy store. In the known force store guide rods are provided, on which the pull-up carriage and the jump carriage are mounted to be longitudinally movable independently of one another. At the same time the guide rods form the guide for the force storage springs in such a manner that in each instance a force storage spring surrounds a respective guide rod. The pull-up carriage is moved linearly relative to and towards the jump carriage by an eccentric connected with the drive shaft and the force storage springs disposed therebetween are thereby stressed. When the pull-up carriage has reached its new end position, locking of the jump carriage is released. This now abruptly, since it stands under the force of the stressed force storage springs, tracks in similarly linear manner the preceding linear movement of the pull-up carriage. It is known from DE-PS 19 56 369 and E-PS 28 06 282 mentioned in the introduction to convert this abrupt movement of the jump carriage by means of a roller, which engages in a groove, into a rotational movement of a driven shaft. This known form of conversion of a longitudinal movement into a rotational movement by means of a rotating roller or a slide block has the disadvantage that at the beginning of each movement relatively little force is available, for example in the middle of each movement the force reaches its maximum and decays again towards the end of movement. This course of torque is unsuitable for specific switching processes in which on each actuation the contacts of a plurality of contacts have to be actuated in succession in a predetermined actuating sequence. In addition, due to the only small torque available at the end of the switching over process the risk exists that the on-load tap changer does not reach its end position with certainty. It is further known from WO 02/31847 to convert the longitudinal movement of the jump carriage into a rotational movement by means of a toothing in which a gearwheel connected with the driven shaft engages. In this form of movement conversion a constant force development results, which is similarly disadvantageous for specific switching sequences. Moreover, the constant course of torque cannot be varied. It is the object of the invention to indicate a force store of the kind stated in the introduction which allows, in simple manner, variation of the course of torque at the driven shaft, i.e. after conversion of the longitudinal movement of the jump carriage into a rotational movement. In particular, it shall be possible to achieve by simple technical means that the translation ratios can vary and that a high torque is available at the end of the switching, which ensures that in all circumstances the end position is securely reached and the force store latched again. This object is fulfilled by a force store with the features of the first patent claim. The subclaims relate to particularly advantageous developments of the invention. The force store according to the invention with its arrangement of two rollers in conjunction with the co-operation, similarly in accordance with the invention, of these rollers with a specially designed gate guide in which the rollers are guided and with which, by their flanks, they alternately come into engagement allows adaptation within wide limits of the specific time and torque courses of the rotational movement, which is derived from the abrupt linear movement of the jump carnage, of a drive shaft to the most diverse switching processes and actuating sequences. The translation ratio of the force store, both torque and speed, can be varied in simple manner by the spacing of the two rollers. A higher level of torque is provided by the arrangement according to the invention particularly also at the end of the movement of the jump carriage and thus of the drive shaft when the switching-over of the on-load tap changer is almost completed. The invention shall be explained by way of example in more detail in the following on the basis of drawings, in which: Fig. 1 shows a force store according to the invention in perspective illustration obliquely from above, Fig. 2 shows the same force store in another perspective illustration obliquely from above, Fig. 3 shows the roller arrangement of the inventive force store by itself from above and Fig. 4 shows this roller arrangement in a schematic perspective illustration obliquely from above. Figures 1 and 2 show a force store according to the invention in different illustrations, wherein not all individual parts described in more detail in the following are recognisable in each illustration and thus also not all reference numerals are entered. In addition, the force storage springs are omitted in Figure 1 for the sake of better illustration. As known from the state of the art mentioned in the introduction, there is provided, also in the force store described here, an eccentric disc 1 which is connected with a drive shaft (not illustrated) and which actuates a pull-up carriage 3 in that it acts on entrainer blocks 2 arranged at the top and bottom in movement direction of the pull-up carriage 3. The force store has in this example of embodiment three parallelly running guide rods 4, 5 and 6 extending longitudinally of the movement direction of the pull-up carriage 3, wherein here two of the rods are surrounded by force storage springs 8. A different number of guide rods and force storage springs is also possible within the scope of the invention. The pull-up carnage 3 has. at its two ends, linear bearings 7 which each surround a respective one of the guide rods 4, 5 and 6. The pull-up carriage 3 is stably mounted by these linear bearings and guided in defined manner in its movement. The force storage springs 8 are each fixed by one end thereof in movement direction at the top and bottom in a respective displaceable spring web and are supported there. A jump carriage 9 is guided below the pull-up carriage 3 to be longitudinally movable in the same direction as this. This jump carriage 9 again has, at its two ends, linear bearings 10 which similarly each surround a respective one of the guide rods 4, 5 and 6. Other constructional designs of pull-up carriage 3 and jump carriage 9 and the mountings thereof are also possible within the scope of the invention. It is only important that pull-up carriage 3 and jump carriage 9 each execute a linear movement, which is indicated in the figures by double arrows. An arm 11 carrying two downwardly directed rollers 12 and 13 is fastened to the jump carriage 9 at the lower side thereof remote from the pull-up carriage 3. These rollers 12 and 13 are arranged in such a manner that they are disposed in a horizontal plane in a line perpendicular to the direction of movement of the jump carriage 9. This is evident particularly clearly from Figure 4. The movement direction of the arm 11 shown there, which corresponds with that of the jump carriage 9, is indicated by a double arrow. The two rollers 12 and 13 are fastened on the arm 11 in a line standing perpendicularly thereto. The free, downwardly directed rollers are themselves rotatable. The two rollers 12 and 13 correspond with a specially formed gate guide 14, which is formed in the shape of a groove in a flywheel 15. The specially designed gate guide 14 is explained in more detail further below. The described flywheel 15 is in turn connected with a driven hub 18, which has splines 19 in turn connected with a driven shaft (not illustrated), which transfers the generated rotational movement to the on-load tap changer and thereby actuates this. The already mentioned gate guide 14 has an inner profile 16 and an outer profile 17, wherein the two profiles 16 and 17 do not extend parallel in the middle region. In other words: the inner width of the gate guide 14 is not constant, but changes. The gate guide 14 has a Y-shaped profile, wherein the spacing between inner profile 16 and outer profile 17 is approximately constant in the area of the outer regions of the three limbs of the Y and at least approximately corresponds with the diameter of the rollers 12 and 13. Thus, in each instance one of the two rollers 12 and 13 can be guided in shape-locking manner in these outer regions. In its middle region the width of the gate guide 14 enlarges so that in this region one of the two rollers 12 and 13 is freely movable. The movement sequence in the case of pull-up of the force store according to the invention is as follows: A drive shaft (not illustrated) begins to continuously rotate and with it the eccentric disc 1, which slides on the corresponding entrainer block 2 and thus displaces the pull-up carriage 3 in longitudinal direction on the guide rods 4, 5 and 6. The force storage springs 8 are thereby stressed. If the pull-up carriage 3 has approximately reached its new end position, these force storage springs 3 are biased to maximum extent. Up to this point in time the jump carnage 9 is still locked, so that it cannot follow the movement of the pull-up carriage 3. Shortly before the new end position of the pull-up carriage 3 the locking is then released by a suitable actuating element. This is known in principle from the state of the art. As a result of this released locking the jump carriage 3 now abruptly tracks, due to the force of the stressed force storage springs 8, the movement of the pull-up carriage 3. If it has reached its new end position, a locking takes place again, i.e. mechanical means latch the jump carriage 9 in the new position again; the force store is ready for the next switching. Simultaneously with the released jump carriage 9 the arm 11 fastened thereto also moves. The two rollers 12 and 13 fastened to the arm similariy execute this abrupt linear movement on parallel tracks. Initially one roller 12 stands in shape-locking engagement with the gate guide 14 of the flywheel 15. The other roller 13 is initially freely movable in the inner, wider part of the guide gate 14. In the further course of the linear movement of the two rollers 12 and 13 the first roller 12 initially standing in shape-locking engagement rotates the flywheel 15 until the roller 12, due to this rotation, reaches the middle, wider region of the gate guide 14. Through the rotation of the flywheel 15 the relative position of the gate guide 14 with respect to the rollers 12 and 13 thus changes. As a consequence, the second roller 13, which hitherto was running freely, now comes into shape-locking engagement with the gate guide 14 and rotates this and thus the flywheel 15 in the middle region again in the same direction. Subsequently the first roller 12 again passes into shape-locking engagement until the end setting is reached. The second roller at the same time now comes out of engagement and can move freely without shape-locking couple. In accordance with the invention the linear movement of the jump carriage 9 is transferred by the two rollers 12 and 13 in three segments successive in time into a rotational movement of the flywheel 15: initially by a shape-locking couple of the first roller 12 in the gate guide 14 with free-running second roller 13, then by a shape-locking couple of the second roller 13 in the gate guide 14 with free-running roller 12 and finally again by a shape-locking couple of the first roller 12 in the gate guide 14 with free-running second roller 13. In addition, smoothing out of the generated rotational movement can be effected in particularly advantageous manner by the mass of the flywheel 15. In the next actuation of the force store the described movement sequence of pull-up carriage and jump carriage 9 as well as the transfer of the linear movement thereof by means of the rollers 12 and 13 and the gate guide 14 into a rotational movement of the flywheel 15 is carried out in the other direction. The movement sequences of the individual components thus elapse in opposite direction; the force store has a lefthand and righthand end setting, between which there is alternating change on each switching over. Several advantages in the force store result due to the described conversion of the linear movement into a rotaflonal movement in accordance with the invention: first of all a variable translation is given in simple manner; the torque is particularly high just at the beginning and the end of the actuafion of the on-load tap changer when it is needed. A high torque is significant particularly at the end of each switching over so as to ensure that the end position of the force store is securely reached; it is reliably latched in this end position and thus the on-load tap changer reaches its new stationary position after the switching over. The invention takes this into account. In addition, the gate guide 14 is variable within wide limits with respect to its geometry. The inner profile 16 and the outer profile 17 can be changed in numerous ways in their shape and also in their spacing from one another. An adaptation to the most diverse switching sequential processes and actuating sequences of the most diverse forms of onload tap changer is thus possible. Patent Claims 1. Force store for an on-load tap changer, wherein a longitudinally movable pull-up carriage connected with a drive shaft and a similarly longitudinally movable jump carriage connected with a driven shaft are provided, wherein at least one force storage spring is provided between pull-up carriage and jump carriage, wherein the pull-up carriage is linearly movable in such a manner by the rotating drive shaft in an alternative one of two opposite directions on each switching of the on-load tap changer that the at least one force storage spring can be stressed, wherein after reaching the new end setting of the pull-up carriage the jump carriage locked until then is releasable in such a manner that it abruptly tracks the movement of the pull-up carriage, and wherein the linear movement of the jump carriage can be converted into a rotational movement of the driven shaft, characterised in that two rollers (12, 13) are arranged at the side of the jump carriage (9) facing the driven shaft and run in a rotatable gate guide (14), which faces them and is in turn connected with the driven shaft, that the gate guide (14) has an inner profile (16) and outer profile (17) of such a kind that during a first part of each movement of the jump carriage (9) initially the first roller (12) is guided in shape-locking manner in the gate guide (14) and the second roller (13) is freely movable, during a second part of each movement of the jump carriage (9) the second roller (13) freely movable until then is guided in shape-locking manner and the first roller (12) guided in shape-locking manner until then is freely movable and during a third part of each movement the first roller (12) freely movable until then is again guided in shape-locking manner and the second roller (13) guided in shape-locking manner until then is freely movable. 2. Force store according to claim 1, characterised in that the gate guide (14) has an at least approximately Y-shaped track, wherein the spacing between inner profile (16) and outer profile (17) in the area of the outer regions of the three limbs of the Y-shaped track is constant and substantially corresponds with the diameter of the rollers (12, 13) and wherein in the centre region of the gate guide (14) the width thereof enlarges in such a manner that in this region one of the two rollers (12 or 13) is freely movable. 3. Force store according to claim 1 or 2, characterised in that an arm (11) carrying the two rollers (12, 13) is fastened to the jump carriage (9). 4. Force store according to one of claims 1 to 3, characterised in that the two rollers (12, 13) are arranged in a horizontal plane and in a line perpendicular to the naovement direction of the jump carriage (9). 5. Force store according to one of claims 1 to 4, characterised in that the gate guide (14) is formed in a flywheel (15) which is in turn connected with the driven shaft. q

Documents:

5275-CHENP-2007 AMENDED CLAIMS 19-11-2012.pdf

5275-CHENP-2007 AMENDED PAGES OF SPECIFICATION 19-11-2012.pdf

5275-CHENP-2007 OTHER PATENT DOCUMENT 19-11-2012.pdf

5275-CHENP-2007 EXAMINATION REPORT REPLY RECEIVED. 19-11-2012.pdf

5275-CHENP-2007 FORM-3 19-11-2012.pdf

5275-CHENP-2007 CORRESPONDENCE OTHERS 17-05-2012.pdf

5275-CHENP-2007 ENGLISH TRANSLATION 17-05-2012.pdf

5275-CHENP-2007 CORRESPONDENCE OTHERS 16-04-2012.pdf

5275-chenp-2007-abstract.pdf

5275-chenp-2007-claims.pdf

5275-chenp-2007-correspondnece-others.pdf

5275-chenp-2007-description(complete).pdf

5275-chenp-2007-drawings.pdf

5275-chenp-2007-form 1.pdf

5275-chenp-2007-form 26.pdf

5275-chenp-2007-form 3.pdf

5275-chenp-2007-form 5.pdf

5275-chenp-2007-pct.pdf