Title of Invention

A PRESELECTOR OF A TAP SWITCH

Abstract

The present invention relates to a tap switch, wherein the preselector comprises a Iseparate, tubular insulating material housing, the wall of which has bores in which fixed preselector contacts are fastened, wherein the fixed preselector contacts have an electrically connectible contact region extending in the interior of the insulating material housing, a contact shank penetrating the wall of the insulating material housing, fastening means extending outside the insulating material housing, and a connection surface, characterised in that the contact region consists of a contact ring which is arranged substantially horizontally and concentrically relative to the inner wall of the insulating material housing, that the profile of each bore is enlarged by at least one mounting slot which extends in longitudinal direction of the insulating cylinder and the width of which is greater than the thickness of the connection surface of the respective fastened preselector contact, that the contact shank has at least one locking surface with a specific geometric profile, that a respective positioning part is inserted into the profile of the bore enlarged by at least one mounting slot and is geometrically formed in such a manner that it at least approximately fills out this profile, and that the positioning part has an inner circular profile which corresponds with the contact shank in such a manner that at the inner circular profile at least one locking profile is formed thereon and corresponds with the at least one locking surface in such a manner that a mechanically positive locking of the preselector contact is effected.

Full Text

Contact Arrangement at a Preselector The invention relates to a contact arrangement at a preselector of a tap switch. In tap switches it has long been usual practice to provide a preselector to increase the respective possible setting range. This serves either as a coarse selector for forward and counter switching of the tap winding or as a changer for reversing.the tap winding at the start or the end of the coarse step. Such a known preselector usually consists of three fixed preselector contacts for each phase, wherein in each instance one of the two fixed contacts, i.e. the "plus" contact or the "minus" contact, is connected with the third fixed contact, i.e. the "0" contact. A preselector of a tap switch, in which the preselector extends outside the insulating material cylinder of the tap switch in the longitudinal direction thereof, is known from the Bulgarian company publications "On-Ioad Tap Changer Type RS12" and "On-load Tap Changer Type 16". The fixed preselector contacts are arranged in a line, have a spherical contact surface and are electrically connected by a switching rod, which is displaceable in longitudinal direction, with a contact bridge in the above-described manner. Moreover, a preselector constructed as a multiple coarse selector and having a separate housing is known from DE 93 08 424 U1. The actuation of this tap selector in that case is effected by a rotatable switch shaft. The fixed preselector contacts similarly each have a spherical contact surface which can be electrically connected by means of movable contacts arranged at the rotatable switch shaft and pivotable therewith. Finally, in DE 19836463, which is not prior published, there has been proposed a preselector accommodated as a subassembly separate from the tap switch in a separate insulating material housing, in the interior of which a longitudinally displaceable switch rod extends. The fixed preselector contacts are in that case constructed to be circular and arranged concentrically around the switch rod in different planes in the interior of the insulating material housing. The mounting of such circular, concentric fixed preselector contacts in the interior of such a tubular insulating material housing has, however, proved extraordinarily difficult. In that case it has to be taken into consideration that for stress reasons the tubular insulating material supporting the entire preselector is of integral construction and moreover should not have any large openings, i.e. interruptions of the insulating material, but on the other hand such openings are required in order to place the fixed preselector contacts in the interior and to fasten them there. It is accordingly the object of the invention to counteract this deficiency and to indicate a contact arrangement in which a circularly constructed fixed preselector contact is fastenable in simple manner in a tubular insulating material housing receiving the preselector. This object is met by a contact arrangement of the kind according to category and with the features of the first patent claim. The subclaims relate to particularly advantageous developments of the invention. The contact arrangement according to the invention exhibits a series of advantages. For one thing, the fixed preselector contact itself forms, by its shape, an ideal electrode and makes optimal use of the available inner diameter of the insulating material cylinder in which it is fastened. It is to be fastened from the inside in that, as will be explained in more detail later, it is introduced into the interior itself and mounted in such a manner that its connecting means lead outwardly through corresponding bores. Thus, no further openings or cut-outs are necessary in the insulating material. The entire contact arrangement is suitable not only for a vertical, but also for a horizontal connection outside the insulating material cylinder in the same manner. Moreover, a fastening of the preselector contacts in a manner which is rotationally secure and compensates for tolerances is made possible by the contact arrangement according to the invention and finally the fastening of additional shielding means and shielding rings inclusive of potential coupling is possible. The invention shall be explained in the following in more detail by way of example with reference to drawings, in which: Fig. 1 shows a perspective illustration (exploded drawing) of a contact arrangement according to the invention; Fig. 2 shows a lateral sectional illustration of this contact arrangement; Fig. 3 shows a detail thereof at the tubular insulating material housing; Fig. 4 shows a positioning part, on its own, of the device according to the invention; Fig. 5 shows a fixed preselector contact on its own, in particular (a) from above and (b) from the front; and Fig. 6 shows different sequences in the installation of a fixed preselector contact in the tubular insulating material housing, in particular (a) with a vertical connection surface and (b) with a horizontal connection surface. The contact arrangement according to the invention is illustrated in its entirety and in different subassemblies or individual parts in Figures 1 to 5. A tubular insulating material housing 1 has a bore 11 for each fixed preselector contact to be fastened. For reasons of simplicity, only one of these bores is shown each time. The bore 11 is widened, in longitudinal direction of the insulating material housing 1, upwardly by an upper-mounting slot 12 and downwardly by a lower mounting slot 13, so that altogether an opening with the profile illustrated in Fig, 3 in detail results each time. The fixed preselector contact 2 comprises the actual contact ring 21, which extends in the interior of the insulating material housing concentrically around the drive shaft (not illustrated) and which is electrically connectible by the movable preselector contacts or contact bridges (similarly not illustrated). Each fixed preselector contact 2 further comprises a contact shank 22 guided outwardly through the corresponding bore 11 of the insulating material housing 1. A defined bearing of the preselector contact 2 against the inner wall of the insulating material housing 1 is ensured by an abutment 23, which is constructed as an electrode. The contact shank 22 has at its otherwise cylindrical circumference two lateral locking surfaces 24, 25, the function of which is described in more detail further below. A thread 26 is provided in the front region at the contact shank 22 and a connection surface 27 with a connection bore 28 is provided as the outer end. The corresponding electrical connecting lines, which lead to the respective fixed preselector contact, are fastened there. The contact arrangement according to the invention further comprises a positioning part consisting of insulating material. This is illustrated in detail in Figure 4. The positioning part 3 has an upper mounting slot cover 31 and a lower mounting slot cover 32, which extend in alignment. These two mounting slot covers 31, 32 correspond in their shape with the already described mounting slots 12, 13 at the corresponding bore 11. The positioning part 3 otherwise has an outer circular profile 33 corresponding with the diameter of the bore 11. In addition, it has an inner circular profile 36 corresponding with the diameter of the contact shank 22. Two lateral locking profiles 37, 38 are formed on this inner circular container 36 and correspond in turn with the two locking surfaces 24, 25. In the mounted state the positioning part is inserted into the bore 11 as well as the mounting slots 12, 13 and at the same time acts by the associated locking surfaces 24, 25 at the fixed preselector contact 2 and the locking profiles 37, 38, as rotational securing for the fixed preselector contact. An abutment 35 is in addition formed on the positioning part. 3 and prevents this part from being able to slip through into the interior of the insulating material housing 1. A shielding ring 4 is, moreover, plugged onto the outwardly projecting contact shank 22 after the positioning part 3 has been inserted in the described manner; the entire arrangement is fastened by a fastening nut 9 and washers 5, 6, 7, 8 additionally arranged therebetween, in that the fastening nut 9 is tightened on the thread 26. It is also possible to fasten a further preselector shielding means without additional fastening means, as is illustrated in Figure 2. The mounting of a fixed preselector contact 2 is shown in Figure 6 in several sequences. It is apparent that the contacts are pushed by means of suitable devices (not illustrated), possibly pull devices, into the interior up to the region of the corresponding bore 11 with the mounting slots 12, 13 at which the fastening is to take place. A slow orientation of the respective fixed preselector contact 2 takes place there, wherein the contact shank 22 with the connection surface 28 formed thereon is pivoted outwardly through the profile formed by the respective bore 11 and the two mounting slots 12 and 13. When the preselector contact 2 has reached its final position, i.e. the contact ring 21 is in horizontal position, the positioning part 3 is plugged on from the outside and thus the rotational securing is realised by means of the co-operation, which was expressly described further above, of locking surfaces 24, 25 and locking profiles 37, 38. Subsequently, the entire arrangement is fastened by turning the fastening nut 9 on the thread 26, optionally with interposition of further components; the mounting is concluded. Numerous geometric constructions are in that case possible for the respective locking surfaces 24, 25 and the locking profiles 37, 38 co-operating therewith; the arrangement is not restricted to the lateral flattening, as described here, at the contact shank 22. The positioning part 3 is advantageously dimensioned in its thickness in such a manner that it corresponds with the thickness of the tubular insulating material housing 1, so that in the mounted state it is supported inwardly at the abutment 23 and disappears completely into the surface of the insulating material housing 1. Thus, a mechanically positive, rotationally secure locking of the fixed preselector contact 2 mounted from the inside is guaranteed: it is itself fixed by the co-operating corresponding locking surfaces 24, 25 on the one hand and locking profiles 37, 38 on the other hand relative to the positioning part 3. This in turn is fixed relative to the insulating material housing 1 by its upper and lower mounting slot covers 31, 32 which respectively engage in the upper and lower mounting slots 12, 13 of the corresponding bore 11. A firm, force-locking connection is additionally effected by the fitting of a fastening nut from outside on the thread 26. In Figure 6 it is also already shown that the described mounting is possible independently of whether the corresponding connection surface 27 is to be arranged horizontally or vertically in the mounted state. In the first case the mounting takes place in vertical position of the contact ring 21 and the contact shank 22 must be rotated from the outside through 90 degrees before insertion of the positioning part 3. In the second case such a rotation is not required. Reference Numeral List 1 tubular insulating material housing 11 bore for reception of fixed contact 12 upper mounting slot 13 lower mounting slot 2 fixed preselector contact 21 contact ring 22 contact shank 23 abutment 24 first lateral locking surface 25 second lateral locking surface 26 thread 27 connection surface 28 connection bore 3 positioning part 31 upper mounting slot cover 32 lower mounting slot cover 33 outer circular profile 34 radial abutment 35 36 inner circular profile 37 first locking profile 38 second locking profile 4 shielding ring 5 washer 6 washer 7 washer 8 washer 9 fastening nut 10 preselector shield Patent Claims: 1. Contact arrangement at a preselector of a tap switch, wherein the preselector comprises a separate, tubular insulating material housing, the wall of which has bores in which fixed preselector contacts are fastened, wherein the fixed preselector contacts have an electrically connectible contact region extending in the interior of the insulating material housing, a contact shank penetrating the wall of the insulating material housing, fastening means extending outside the insulating material housing, and a connection surface, characterised in that the contact region consists of a contact ring (21) which is arranged substantially horizontally and concentrically relative to the inner wail of the insulating material housing (1), that the profile of each bore (11) is enlarged by at least one mounting slot (12, 13) which extends in longitudinal direction of the insulating cylinder (1) and the width of which is greater than the thickness of the connection surface (27) of the respective fastened preselector contact (2), that the contact shank (22) has at least one locking surface (24, 25) with a specific geometric profile, that a respective positioning part (3) is inserted into the profile of the bore (11) enlarged by at least one mounting slot (12, 13) and is geometrically formed in such a manner that it at least approximately fills out this profile, and that the positioning part (3) has an inner circular profile (36) which corresponds with the contact shank (22) in such a manner that at the inner circular profile (36) at least one locking profile (37, 38) is formed thereon and corresponds with the at least one locking surface (24, 25) in such a manner that a mechanically positive locking of the preselector contact (2) is effected. 2. Contact arrangement according to claim 1, characterised in that the positioning part (3) has an outer circular profile (33) corresponding with the respective bore (11) and comprises mounting slot covers (31, 32) which are formed thereon and correspond with the mounting slots (12, 13), 3. Contact arrangement according to claim 1 or 2, characterised in that the thickness of the positioning part (3) is dimensioned in such a manner that it approximately corresponds with the thickness of the wall of the insulating material housing (1). 4. Contact arrangement according to one of claims 1 to 3, characterised in that the fastening means consist of a thread (2) disposed on the contact shank (22) in the outwardly facing region thereof and a fastening nut (9) able to be screwed on from the outside. 5. Contact arrangement according to claim 4, characterised in that a shielding ring (4) and/or further means for shielding (10) are additionally securable by the fastening nut (9). 6. Contact arrangement at a preselector of a tap switch substantially as herein described with reference to the accompanying drawings.

Documents:

in-pct-2001-1618-che-abstract.pdf

in-pct-2001-1618-che-claims filed.pdf

in-pct-2001-1618-che-claims granted.pdf

in-pct-2001-1618-che-correspondnece-others.pdf

in-pct-2001-1618-che-correspondnece-po.pdf

in-pct-2001-1618-che-description(complete)filed.pdf

in-pct-2001-1618-che-description(complete)granted.pdf

in-pct-2001-1618-che-drawings.pdf

in-pct-2001-1618-che-form 1.pdf

in-pct-2001-1618-che-form 19.pdf

in-pct-2001-1618-che-form 26.pdf

in-pct-2001-1618-che-form 3.pdf

in-pct-2001-1618-che-form 5.pdf

in-pct-2001-1618-che-other documents.pdf

in-pct-2001-1618-che-pct.pdf