Safety device with flexible conductive band

Abstract

Safety device (1) for a power distribution system with at least one fuse (NH), in particular in the form of a fuse or NH fuse, as well as ladders (5; ST-L1, ST-L2, ST-L3) and busbar connection angles (SW-L1, SW-L2, SW-L3) within the safety device (1), characterized in that either - at least one ladder (5; ST-L1, ST-L2, ST-L3) is formed at least partially or entirely from a flexible electrically conductive material, in particular in the form of a strip or flexible copper strip (5). and / or - a flexible electrically conductive strip (5), in particular a flexible copper strip, is arranged parallel to at least one ladder (ST-L1, ST-L2, ST-L3) made of bent copper profile, at least sectionally or over its entire length and adjacent to it. and / or - the fuse device (1) has a flexible electrically conductive strip (5), in particular a copper strip, for contacting the terminal tab (2) of a fuse (NH) that can be inserted into the fuse device (1).

Description

[0001] The present invention relates to a safety device for a power distribution system comprising at least one fuse, in particular in the form of a fuse or NH fuse, as well as ladders and busbar connection angles within the safety device.

[0002] A generic safety device, also called a safety strip, is previously known from DE 10 2022 113 758 A1 and in the Fig. 1, Fig. 2 to Fig. Figure 3 shows and explains in more detail. Further safety strips are known from European patent application EP 1 058 283 A2 and German patent application DE 199 13 017 A1.

[0003] The spring-loaded terminals each have only a small contact area, resulting in a relatively high contact resistance to the fuse's terminal tab and causing local heating of the spring-loaded terminal and the connected risers ST-L1, ST-L2, and ST-L3. This heating increases their electrical resistance, which, due to their length, negatively impacts energy transfer and leads to increased losses. The heating of contacts FK-L1a, FK-L2a, and FK-L3a is less critical because the busbar connection angles SW-L1, SW-L2, and SW-L3 are relatively short and connected to the busbars SL1, SL2, and SL3, allowing for relatively good heat dissipation. Therefore, excessive heating is unlikely to cause problems in this area of ​​the fuse device.

[0004] The object of the present invention is to reduce the heating described above, at least in the area of ​​the spring terminals, in order to also reduce losses and / or to realize a simple and cost-effective connection from a spring terminal to a terminal block.

[0005] This problem is solved according to the invention with a locking device having the features of claim 1. Advantageous embodiments of the locking device according to claim 1 result from the features of the dependent claims relating back to claim 1.

[0006] The invention is advantageously characterized in that it provides three solutions for solving the problem, which can be implemented either individually or in any combination with one another in a safety device according to the invention. The following solution options are claimed: 1. that at least one ladder is formed at least partially or entirely from flexible electrically conductive material, in particular by a flexible copper strip and / or 2. that a flexible, electrically conductive strip, in particular a flexible copper strip, is arranged parallel to at least one ladder made of bent copper profile, at least in sections or over its entire length and adjacent to it, and / or 3. that the fuse device has a flexible copper strip for contacting the terminal of a fuse that can be inserted into the fuse device.

[0007] With solution 1, in which the ladder is simply replaced by a flexible electrically conductive band, in particular in the form of a copper band, the complex and costly bending process of the ladder is eliminated, since the flexible band can simply be bent by hand during its installation and laid and fastened in the housing of the safety device, which makes it more cost-effective and easier to manufacture and install the safety device according to the invention.

[0008] The second solution, in which a flexible conductive strip is applied to a ladder at least in sections and laid parallel to it, advantageously increases the conductor cross-sectional area of ​​the ladder in certain areas or advantageously over its entire length, thereby reducing its electrical resistance. At the same time, heat dissipation from the spring terminal to the cable terminal is improved.

[0009] The third solution involves using a flexible, electrically conductive strip, particularly made of copper or a copper alloy, which makes contact with at least part of the contact surface of the fuse's terminal. Due to the flexibility of the copper strip, it presses against the fuse's terminal over a large area, resulting in low contact resistance. One or two flexible, electrically conductive strips can be used. These can extend all the way to the terminal. Alternatively, the strip can be connected to a rigid conductor just beyond the terminal, forming the bridge conductor from that point onward. The flexible strip can also be run independently to the terminal, or it can be arranged parallel to a rigid, and possibly bent, copper profile to increase the conductor cross-section within the housing.

[0010] As already mentioned above, the invention also provides for any combination of the three possible solutions in a safety device or strip according to the invention.

[0011] Advantageously, a retaining element can be provided to which the flexible conductive strip is attached or rests. This element can serve solely to guide and / or hold the strip. Alternatively, the strip can also be fastened to the retaining element by gluing, riveting, clamping, screwing, etc. The retaining element can be a bent sheet metal piece, with appropriate bends defining the routing path of the strip.

[0012] The retaining element can be located, in particular, in the area of ​​the terminal block for the fuse's connecting lug within the housing. Advantageously, the retaining element also serves to provide or generate the necessary contact pressure for the terminal block. For this purpose, the retaining element is advantageously elastic, so that when the connecting lug is inserted into the terminal block, the retaining element is tensioned or pivoted from its rest position, thereby generating a spring force that provides the necessary pressure for permanent and secure contact between the connecting lug and the terminal of the fuse device.

[0013] The retaining element can advantageously be arranged, and in particular attached, to the housing of the locking device. It is also possible for the retaining element to fit snugly into a corresponding recess in the housing of the locking device. Of course, the retaining element can also be fastened to the housing of the locking device by means of screws.

[0014] To ensure the secure routing of the strap, appropriate walls and guide surfaces can be provided in the housing, which is advantageously made of injection-molded plastic. This also ensures that the strap is correctly routed within the housing of the securing device during assembly.

[0015] As already explained, the flexible tape, in particular copper tape, can advantageously form a contact surface for contacting the terminal of a fuse, especially an NH fuse, which can be inserted into the fuse holder, with the retaining element generating the contact force of the copper tape against the terminal. For this purpose, the retaining element advantageously has a section shaped to match or corresponding to the contact surface of the terminal, on the side of which facing the terminal the flexible conductive tape rests. This advantageously ensures that the tape makes contact with the terminal of the fuse over the largest possible area, thereby significantly improving the contact resistance.

[0016] In another possible embodiment, the retaining element can form a slot-shaped contact into which the connecting tab of the fuse can be inserted, wherein the retaining element is designed such that the connecting tab is encompassed from at least three sides and / or clamped from two sides.

[0017] The retaining element rests on both sides against the contact surfaces of the fuse's connecting tab and generates the contact force itself by being tensioned or spread by the connecting tab when the retaining element is inserted into the fuse device.

[0018] Advantageously, the flexible conductive strip is inserted into the slot formed by the retaining element to such an extent that it makes extensive contact with the fuse's connecting tab, which is inserted into the slot. The strip can also be arranged in the slot so that it makes contact with the connecting tab on both sides.

[0019] In a further possible embodiment, the invention provides that two retaining elements are provided for each contact with a terminal tab of a fuse, to which a flexible conductive strip is attached. This advantageously achieves a further reduction in contact resistance.

[0020] In the embodiments described above, the copper cross-sectional area of ​​the flexible copper strip is adapted to the maximum electrical power to be transmitted.

[0021] The width of the flexible copper strip can be at least 0.5 to 1.5 times, in particular 0.9 to 1.2 times, the height of the contact surface of the terminal of a fuse.

[0022] The invention is explained in more detail below with reference to the drawings. They show: Fig. 1: a top view of three 3-phase fuse strips known from the prior art, arranged side by side, which are arranged above three busbars; Fig. 2: a 3-phase fuse strip known from the prior art in top and side view; Fig. 3: a 3-phase fuse strip known from the prior art in side view, wherein only the components essential to the invention of the fuse strip are shown; Fig. 4: Perspective view of a first possible embodiment of the invention; Fig. 5: Perspective section view of section A - A through the safety strip according to Fig. 4; Fig. 6: Cross-sectional view of section A - A through the safety strip according to Fig. 4; Fig. 7: Cross-sectional view of section B - B through the safety strip according to Fig. 4; Fig. 8a-c: various perspective views of the flexible conductor without the fuse strip housing; Fig. 9a-g: perspective views of a second possible embodiment of the invention; Fig. 10: third possible embodiment of the invention; Fig. 11: fourth possible embodiment of the invention; Fig. 12: fifth possible embodiment of the invention; Fig. 13a: sixth possible embodiment of the invention in perspective view; Fig. 13b: Front view of the embodiment according to Fig. 13a; Fig. 14a: seventh possible embodiment of the invention in perspective view, in which the flexible conductive strip is held by a retaining plate which is attached to the housing of the safety strip, with a counter-pressure element also attached to the housing; Fig. 14b: Design according to Fig. 14a in side view.

[0023] The Fig. Figure 1 shows a top view of three adjacent 3-phase fuse strips 1, 1' and 1'', which are arranged in front of the three parallel busbars SL1, SL2, SL3, which are well known. The fuse strips 1, 1', 1'' are not fitted with fuses. The busbars SL1, SL2 and SL3 are each connected via busbar connection brackets SW-L1, SW-L2, SW-L3 with spring-loaded terminals FK-Lxa, with x = 1 to 3, wherein the spring-loaded terminals are for contacting and holding the fuse links NHiKa, NHiKb, with i = 1 to 3, and the fuses NH1, NH2, NH3, see Figure 1. Fig. 2 and Fig. 3. The spring terminals FK-Lxb, with x = 1 to 3, are connected via the ladders ST-L1, ST-L2, ST-L3 to the cable terminals AN1, AN2, AN3.

[0024] The Fig. Figure 2 shows a single fuse strip 1 in top and side views. The spring-loaded terminals each have only a small contact area, resulting in a relatively high contact resistance and local heating of the spring-loaded terminals and the connected risers ST-L1, ST-L2, and ST-L3. This heating increases their electrical resistance, which, due to their length, negatively impacts energy transfer and leads to increased losses. The heating of the contacts FK-L1a, FK-L2a, and FK-L3a is less critical because the busbar connection angles SW-L1, SW-L2, and SW-L3 are relatively short and connected to the busbars SL1, SL2, and SL3, allowing for relatively good heat dissipation. Therefore, excessive heating is not a problem in this area of ​​the fuse device.

[0025] The Fig. Figure 3 shows a 3-phase fuse block in side view, with only the essential components of the fuse block shown. Positions W1, W2 and W3 indicate possible areas where the current sensors IS can be arranged on the busbar connection brackets.

[0026] The following section explains various embodiments using the figures.

[0027] The Fig. Figure 4 shows a perspective view of a first possible embodiment of the invention, in which only a part of the fuse device 1 is depicted. A fuse NH1 is shown, inserted into the terminal block FK-L1b provided for it, with its terminal lug 2. The terminal block FK-L1a for the other terminal lug 2' is not shown. The terminal block FK-L1b is formed on one side by a retaining element 6 and the flexible conductive strip 5 arranged thereon, which can in particular be a copper strip, and on the other side by a rigid element 4 with a contact surface 4a. The parts 4, 5, and 6 form an insertion slot 7 into which the terminal lug 2 of the fuse NH1 is pressed when the fuse NH1 is inserted. At least the retaining element 6 is slightly deflectable and is thereby tensioned, so that the terminal lug is held in position by the terminal block FK-L1a with a sufficiently large force.The retaining element 6 is attached to the housing 3 of the locking device by means of a fastening element 10 via its base plate 6d. The flexible band 5 runs between the base plate 6d of the retaining element 6 and a housing wall and is additionally fastened at its upper end 5a to the upper end 6a of the retaining element 6 by means of a fastening element 11. The fastening element 11 can be a fastening screw or a rivet. However, it is also possible to do without such a fastening element if, for example, the flexible band 5 is glued, welded, or soldered to the retaining element 6.

[0028] The band 5 and the part 4, with their upper ends 4b and 5a, form a kind of funnel which serves to guide the connecting flag 2 when inserted into the slot 7.

[0029] Additionally, the terminal block FK-L2a is shown, which has only two blades 8, 9. The terminal 2' of the (not shown) fuse NH2 is pressed between these blades, with the blades 8, 9 then pressing their narrow contact surfaces 8a, 9a against the contact surface of the terminal 2'. Due to the relatively small contact surfaces 8a, 9a, the contact resistance is relatively high, resulting in heat generation in this area. However, the heat generated is quickly and efficiently dissipated via the relatively short (not shown) busbar connection angle to the (also not shown) busbar.

[0030] In contrast, the distance between the terminal block FK-L1b and the cable terminal block AN1 (not shown) (see Fig. 1, Fig. 2 to Fig. 3) relatively long, so that heat transport cannot take place sufficiently well here without the safety device 1 according to the invention overheating, were it not for the fact that the electrical contact resistance at the terminal FK-L1b is not low according to the invention due to the provided flexible band 5.

[0031] The Fig. Figure 5 shows a perspective section view of section A - A through the safety strip 1 according to Fig. 4. It can be seen that the band 5 is guided along below the base plate 6d and then bent upwards by 180° in the area of ​​the side wall 3b of the housing 3, in order to then run with its section 5f parallel to the housing wall 3b in the direction of terminal AN1 (not shown).

[0032] The retaining element 6 can be formed by a bent sheet, in particular a copper sheet, having an outwardly angled upper end section 6a, to which the long straight section 6b adjoins below, which presses the band 5 with its section 5b against the connecting lug 2. The base plate 6d is in turn formed on the adjoining 90° bent section 6c, which is attached to the housing by means of the fastening means 10, thus sufficiently fixing the retaining element.

[0033] The Fig. Figure 6 shows a cross-sectional view of section AA through the safety strip 1 according to Fig. 4. To avoid unnecessary repetition, the following is omitted: Fig. 5 referred.

[0034] A cross-sectional view of section B - B through the safety strip according to Fig. 4 is in Fig. Figure 7 shows how the band 5 with its section 5d runs below the base plate 6d of the retaining element 6, then bends upwards at the edge area and runs with its section 5f above the section 5d in the direction of the terminal AN1.

[0035] The Fig. Figures 8a to 8c show different perspective views of the flexible conductor 5 without the housing 3 of the fuse strip 1. The strip 5 has several kinks that separate its individual sections 5a to 5h from each other. At its end 5i, the strip is ultimately electrically connected to the terminal AN1. Fig. Figure 8b shows what is meant by the height H of the connecting lug 2 of the fuse NH1 and what is meant by the width of the band 5 according to the invention.

[0036] The Fig. Figures 9a to 9g show various perspective views of a second possible embodiment of the invention, in which the strip 5 extends only to the connection point 20, where it is electrically connected to rigid conductor elements 21, 21 and 21''. The rigid conductor elements can be copper plates, which can be spaced apart from each other by means of spacer elements 22, thus providing a larger radiating surface for any heat generated. Fig. Figures 9a to 9c show embodiments with a different number of rigid conductor elements 21. For example, in Fig. 9d only provides for 1 rigid conductor, whereas in Fig. 9c two rigid connecting conductors and in Fig. 9b three connecting conductors are provided.

[0037] The Fig. Figure 10 shows a third possible embodiment of the invention, which is characterized in that the retaining element 26 is formed from a U-shaped sheet metal part, with the flexible band 25 guided around its outer surface. The band 25, with its region 25a and its outwardly facing wall 25a', forms the electrical contact surface for the (not shown) terminal lug 2 of the fuse 1. The clamping slot 27 for the terminal lug 2 is formed by the contact surface 25a' and the contact surface 24a of the counter-pressure medium 24. The band continues at the lower region 5d. The same applies to the region 26d of the retaining element 26, which leads towards the (not shown) base plate.

[0038] The Fig. Figure 11 shows a fourth possible embodiment of the invention, in which the terminal is formed by an M-shaped retaining element 36, the central part of which 36c, 36d forms a slot 37. The flexible band 35 is inserted into the slot 37 from above, and its sections 35c form the contact surface for the fuse's terminal tab (not shown). It is advantageous if both lower ends 36a and 36g of the retaining element 36 are attached or fixed to the housing of the fuse device. The band 35 can be fastened to the retaining element 36 by means of a rivet or fastening screw, which passes through the hole 35a' and a corresponding hole in section 36a. The other end 35g leads to the terminal AN or to a rigid conductor forming the ladder.

[0039] The Fig. Figure 12 shows a fifth possible embodiment of the invention, in which the retaining element 46 is Z-shaped and its sections 46a-e form the receiving slot 47, the end section 46a being slightly angled outwards and, together with the semicircular section 46e, forming an insertion funnel. The flexible band for secure contact with the fuse's terminal (not shown) is only attached to sections 46d and 46e on one side and extends slightly into the lower circular section 46c. This ensures that the band is securely held in the retaining element 46 and is not pulled out of the retaining element by the terminal when the fuse is removed. The retaining element 46 is attached to the housing with its section 46f. The band continues with its section 45d towards the terminal AN.

[0040] The Fig. 13a and Fig. Figure 13b shows a sixth possible embodiment of the invention in perspective and front view. For the terminal block FK-L1b, two retaining elements 56, 56' are provided, each holding a flexible conductive strip 55, 55' in position. The retaining elements 56, 56' are essentially identical in construction, with the two strips 55 and 55' associated with them being guided along the side of the locking device below the base plate 59' of the retaining element 56'. Both ends 55d and 55d' of the strips 55, 55' have through-openings 55h through which an electrical connecting bolt 20, such as that used, for example, in the second embodiment with the Fig. The embodiment shown and explained in 9a-9g is used, reaching through so that the rigid ladder elements 21, 21', 21'' can be connected to the straps 55, 55' via this.

[0041] The Fig. 14a and Fig.Figure 14b shows a seventh possible embodiment of the invention in perspective and side views. In this embodiment, the flexible copper strip 65 is attached to a curved sheet metal strip 66. This sheet metal strip 66 also has a spring function. Opposite it is a U-shaped spring 67, which presses the locking blade 2 against the flexible copper strip 65 and the sheet metal strip 66. Both the sheet metal strip 66 and the U-shaped spring 67 are attached to the housing G of the locking strip. The free upper ends 65a, 66a, 67a of the sheet metal strip 66, the band 65, and the U-shaped spring 67 are angled relative to their perpendicular straight sections 65b, 66b, 67b and form the insertion funnel 68 for inserting the locking blade 2.The strip 65 has a curved section 65c adjacent to a horizontal end section, which serves for connection to a connecting conductor (not shown), which can be formed by a flexible copper strip or at least a rigid copper profile. Naturally, the strip 65 can also be long enough to be directly electrically connected to a terminal AN1-3. Reference symbol list: 1 safety device 2 Connection tab of the NH fuse 2a Contact surface of the connecting flag 2 3 cases 3a, 3b, 3u Housing walls 4 Counter-pressure element for forming a connection terminal 5 flexible conductive tape, especially copper tape Sections 5a-5g of Volume 5 6, 26, 36 retaining element 46, 56 retaining element 6a-6f different sections of the retaining element 6 7, 27, 37 Slot of the terminal block 47, 57 Slot of the terminal block 8, 9 Contact blade of a terminal block 10 Fasteners 11 Fasteners 20 electrical connecting bolts 21, 21', 21'' rigid ladder element 22 spacers A1, A2, A3 possible positions for current measuring sensor AN1 cable terminal for phase L1 for cable connection AN2 cable terminal for phase L2 for cable connection AN3 cable terminal for phase L3 for cable connection B Width of the band 5 F1, F2, F3 possible positions for current measuring sensor FK-L1a, FK-L1b Spring-loaded terminal blocks for fuse blades of the NH1 fuse FK-L2a, FK-L2b Spring-loaded terminal blocks for fuse blades of the NH2 fuse FK-L3a, FK-L3b Spring-loaded terminal blocks for fuse blades of the NH3 fuse H Height of the connecting flag 2 IS current measuring sensor K1, K2, K3 possible positions for current measuring sensor NH1 fuse for phase L1 NH2 fuse for phase L2 NH3 fuse for phase L3 NH1Ka, NH1Kb fuse contacts in the form of blades of the NH1 fuse NH2Ka, NH2Kb fuse contacts in the form of blades of the NH2 fuse NH3Ka, NH3Kb fuse contacts in the form of blades of the NH3 fuse S1, S2, S3 possible positions for current measuring sensor SL1 busbars for phase L1 SL2 busbars for phase L2 SL3 busbars for phase L3 ST-L1 ladder for phase L1 ST-L2 ladder for phase L2 ST-L3 ladder for phase L3 SW-L1 busbar connection angle for phase L1 SW-L2 busbar connection angle for phase L2 SW-L3 busbar connection angle for phase L3 TS temperature sensor W1, W2, W3 possible positions for current measuring sensor QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2022 113 758 A1

[0002] EP 1 058 283 A2

[0002] DE 199 13 017 A1

[0002]

Claims

[1] Safety device (1) for a power distribution system with at least one fuse (NH), in particular in the form of a fuse or NH fuse, as well as ladders (5; ST-L1, ST-L2, ST-L3) and busbar connection angles (SW-L1, SW-L2, SW-L3) within the safety device (1), characterized by that either - at least one ladder (5; ST-L1, ST-L2, ST-L3) is formed at least partially or entirely from a flexible electrically conductive material, in particular in the form of a strip or flexible copper strip (5). and / or - a flexible electrically conductive strip (5), in particular a flexible copper strip, is arranged parallel to at least one ladder (ST-L1, ST-L2, ST-L3) made of bent copper profile, at least sectionally or over its entire length and adjacent to it. and / or - the fuse device (1) has a flexible electrically conductive strip (5), in particular a copper strip, for contacting the terminal tab (2) of a fuse (NH) that can be inserted into the fuse device (1). [2] Safety device (1) according to claim 1, characterized by , that the flexible electrically conductive strip (5, 65), in particular in the form of a copper strip, is held in shape and / or position by means of a retaining element (6, 66), wherein the retaining element (6, 66) is arranged on the housing (3) of the safety device (1), in particular is attached. [3] Safety device (1) according to claim 2, characterized by , that the retaining element (6, 66) is a bent sheet metal against which the flexible electrically conductive strip (5, 65) is in contact, in particular over a flat area. [4] Safety device (1) according to any one of claims 1 to 3, characterized by, that the flexible copper strip (5) is guided by means of guiding means, in particular guiding surfaces, of the housing (3) of the locking device (1). [5] Safety device (1) according to any one of the preceding claims, characterized by , that the flexible copper strip (5) forms a contact surface for contacting the terminal tab (2) of a fuse (NH) that can be inserted into the fuse device (1), wherein the retaining element (6) generates the contact force of the copper strip (5) against the terminal tab (2). [6] Safety device (1) according to any one of the preceding claims, characterized by , that the retaining element (6) has a section (6b; 26a; 36c; 46c; 56c) adapted to or correspondingly shaped to the contact surface (2a) of the connecting lug (2), on the side of which facing the connecting lug (2) the flexible copper strip (5) is located. [7] Safety device (1) according to any one of the preceding claims, characterized by, that the retaining element (36; 46) forms a slot-shaped contact (37; 47) into which the connecting tab (2) of the fuse (NH) can be inserted, wherein the retaining element (36; 46) is designed such that the connecting tab (2) is encompassed from at least three sides and / or clamped from two sides. [8] Safety device (1) according to claim 7, characterized by , that the retaining element (36; 46) rests on both sides against the contact surfaces (2a) of the connecting flag (2) and itself generates the contact force for contacting by the connecting flag (2) tensioning or spreading the retaining element (36; 46) when inserted into the locking device (1). [9] Safety device (1) according to any one of the preceding claims, characterized by , that for contact with a terminal tab (2) of a fuse (NH) two retaining elements (56, 56') and two electrically conductive strips (55, 55') are provided. [10] Safety device (1) according to any one of the preceding claims, characterized by , that a retaining element has a region (6d; 56d) with which it is arranged or attached to the housing (3) of the locking device (1). [11] Safety device (1) according to any one of the preceding claims, characterized by , that the contacting of the connecting flag (2) is carried out via a flexible copper strip (5) which is in contact with at least one rigid conductor section (21) which essentially forms a riser. [12] Safety device (1) according to claim 11, characterized by , that several rigid ladder sections (21, 21', 21'') are arranged parallel to each other, which together form a ladder or several ladders arranged in parallel. [13] Safety device (1) according to any one of the preceding claims, characterized by, that the copper cross-sectional area of ​​the flexible copper strip (5) is adapted to the maximum electrical power to be transmitted. [14] Safety device (1) according to any one of the preceding claims, characterized by , that the width (B) of the flexible copper strip (5) is at least 0.5 to 1.5 times, in particular 0.9 to 1.2 times, the height (H) of the contact surface (2a) of the terminal lug (2) of a fuse (NH).

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