AU2006249268B2

AU2006249268B2 - Electrical connection terminal and electrical switchgear unit comprising one such terminal

Info

Publication number: AU2006249268B2
Application number: AU2006249268A
Authority: AU
Inventors: Robert Diconne; Bernard Lebeau; Daniel Vanzetto
Original assignee: Schneider Electric Industries SAS
Current assignee: Schneider Electric Industries SAS
Priority date: 2005-12-09
Filing date: 2006-12-08
Publication date: 2010-11-18
Anticipated expiration: 2026-12-08
Also published as: EP1796214A1; BRPI0605274A; AU2006249268A1; BRPI0605274B1; CN1979955A; AR057230A1; CN1979955B; FR2894722A1; EP1796214B1; RU2006143718A; RU2416845C2; ES2567155T3; FR2894722B1

Description

pool Section 29 Regulation 3.2(2) AUSTRALIA Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: Electrical connection terminal and electrical switchgear unit comprising one such terminal The following statement is a full description of this invention, including the best method of performing it known to us: 1 ELECTRICAL CONNECTION TERMINAL AND ELECTRICAL SWITCHGEAR UNIT COMPRISING ONE SUCH TERMINAL The present invention relates to an electrical connection terminal for an electrical 5 switchgear unit designed to electrically connect the terminal strip of said unit to a connecting comb and/or to an electrical power supply cable, comprising a contact grip electrically connected to said terminal strip and designed to grip a tooth of said comb in the connected position, and a clamping screw designed, in the clamping position, to clamp a cable against said connecting terminal strip of the unit, and also to an electrical 10 switchgear unit comprising one such terminal, Modular switchgear units are known as described in the document EP 1505692 which are supplied by electrical distribution combs comprising teeth designed to be connected to fast-on connecting devices with a contact grip belonging to the switchgear unit. These 15 units also comprise a clamping terminal for cables, of traditional type, enabling power to be supplied to the comb and therefore to the whole row of units fitted in an electrical cabinet. In such devices, the total current of the row is input by a cable to a terminal of a unit by clamping on the connecting terminal strip, and then flows through the contact grip, and by flexible gripping of the tooth is input to the comb to supply the other units. The 20 contact grip then receives the whole of the current of the row, which means that the manufacturer has to over-dimension the latter for all the units. Another drawback of these systems lies in fact that when current tap-off from a unit of the row has to be performed, the contact grip has to withstand both the feeder current and the 25 tap-off current. Another drawback of this type of terminal lies in the fact that when a short-circuit occurs, a wiring error makes the whole of the contact grips in series withstand the whole of the electrical short-circuit stresses only limited by the line-side circuit breaker. 30 Any discussion of documents, devices, acts or knowledge in this specification is included to explain the context of the invention. It should not be taken as an admission that any of 2 the material formed part of the prior art base or the common general knowledge in the relevant art in Australia on or before the priority date of the claims herein. 5 The present invention proposes an electrical terminal and a switchgear unit comprising same wherein a contact grip of large dimensions does not have to be provided to withstand the current when the terminal is connected to a cable and to a comb, when a tap-off is made and when a short-circuit occurs. 10 In accordance with the present invention there is provided an electrical connection terminal for an electrical switchgear unit designed to electrically connect the terminal strip of said unit to a connecting comb and/or to an electrical power supply cable, including a U-shaped contact grip including a fixed part and a movable part, said contact grip being electrically connected to said terminal strip and designed to grip a tooth of said comb in 15 the connected position, and a clamping terminal designed, in the clamping position, to clamp a cable against said connecting terminal strip of the unit, wherein it includes a means for electrically connecting the cable, the tooth and the terminal strip by clamping the tooth against the terminal strip in the clamping position of the terminal, the tooth being clamped between the fixed part of the contact grip and the movable part of said 20 contact grip in such a way that the current coming from the cable flows through the terminal strip and flows in the tooth without flowing through the movable part of the contact grip. According to a particular embodiment, this terminal comprises a conducting intermediate 25 part electrically connected to the terminal strip and, in the clamping position of the tooth, said tooth is clamped by the above-mentioned means against the intermediate part. According to a particular feature, this intermediate part forms an integral part of the fixed part of the contact grip. 30 According to a particular embodiment of the invention, the terminal is of the tunnel and movable screw type, the hole for insertion of the cable being situated between the tunnel and the contact terminal strip and the hole for insertion of the tooth being situated 2a between the terminal strip and the end of the screw, so that when the connection operation is performed, the cable is clamped between the tunnel and the terminal strip and the tooth is clamped between the terminal strip and the end of the screw. 5 According to a particular feature of the invention, the foot of the screw passes through a hole provided in the movable part of the contact grip. According to another embodiment, the terminal is of the tunnel and movable screw type, the hole for insertion of the cable being situated between the connecting terminal strip and 10 the end of the screw and the hole for insertion of the tooth being situated between the tunnel and the intermediate part, so that in the clamped position of the terminal, the cable is clamped between the terminal strip and the end of the screw and the tooth is clamped between the tunnel and the intermediate part.

3 According to a particular feature, the intermediate part comprises a U-shaped part comprising two branches folded towards one another, the two U-shaped branches clamping the fixed part of the contact grip, the cable being clamped between one of the branches of the intermediate part and the screw and the tooth being clamped between the other branch 5 of the intermediate part and the tunnel. According to another particular embodiment of the invention, the terminal is of the tunnel and movable screw type, the hole for insertion of the cable being situated between the intermediate part and the tunnel and the hole for insertion of the tooth being situated 10 between the intermediate part and the head of the clamping screw so that in the clamped position of the terminal, the cable is clamped between the intermediate part and the tunnel and the tooth is clamped between the intermediate part and the head of the clamping screw. According to a particular feature of the invention, the head of the clamping screw passes 15 through a hole provided in the movable part of the contact grip, the head of the clamping screw clamping the tooth against the intermediate part, and the tunnel clamping the cable against the intermediate part in the clamping position. According to another feature, the intermediate part comprises a part in the shape of a 20 closed U the branches whereof constituting the small sides are folded towards one another and clamped respectively against the cable and the tooth when the clamping operation of the terminal is performed, rotation of the screw moving the tunnel. According to another embodiment, this terminal comprises a means for electrically 25 connecting the cable, the tooth and the terminal strip by clamping the tooth against the terminal strip in the clamping position of the terminal in such a way that the current coming from the cable flows through the terminal strip and flows in the tooth without flowing through the contact grip. 30 According to another embodiment, this electrical connection terminal is of the screw and movable tunnel type, the screw being screwed into the tunnel, said tunnel comprising three openings respectively for passage of a tooth, of the terminal strip and of a cable, tightening 4 of the screw causing upward movement of the tunnel, this movement of the tunnel resulting in the cable being clamped against the terminal strip and the tooth being clamped against said terminal strip, the end of the tooth being designed to be inserted in the contact grip, said contact grip being situated outside the tunnel. 5 In accordance with a further aspect of the present invention there is provided an electrical switchgear unit including the above-mentioned features taken alone or in combination. Comprises/comprising and grammatical variations thereof when used in this specification 10 are to be taken to specify the presence of stated features, integers, steps or components or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. But other advantages and features of the invention will become more clearly apparent 15 from the following detailed description which refers to the accompanying drawings given for example purposes only and in which: - Figures 1 and 2 are two partial cross-sectional views of a switchgear unit according to the invention, comprising a terminal according to a particular embodiment of 20 the invention, respectively for figures 1 and 2 in a position of the terminal connected to a comb and a position of the terminal connected both to a cable and to a comb, - Figures 3 and 4 are two similar views to figures 1 and 2, but representing a terminal according to a second embodiment, - Figures 5 and 6 are two similar views to figures 1 and 2, but representing a 25 terminal according to a third embodiment, - Figures 7, 8 and 9 respectively illustrate the three terminals according to the above three embodiments, in perspective view, - Figures 10 and 11 are two partial cross-sectional views of a switchgear unit according to the invention, comprising a terminal according to a fourth embodiment, 30 respectively for figures 10 and 11, in a position connected to a comb and in a position connected to a cable.

4a In the figures, a connection terminal I can be seen housed in the case B of a circuit breaker and designed to electrically connect the connecting terminal strip 2 of the unit to a comb 3, said comb being fed by a cable 4. 5 According to the embodiment illustrated in figures 1 and 2 and as represented in figure 7, the terminal 1 comprises a tunnel 5, a screw 6, and a contact grip 8 comprising a fixed part 9 and a movable part 10. The screw 6 is screwed into the top part 11 of the tunnel 5 and 10 5 passes through a hole 12 provided for this purpose in the movable part 10 of the contact grip 8. The terminal strip 2 is formed by a U-shaped part comprising two branches 13,14 folded against one another, one 13 of the branches whereof is connected to the contact grip 8 and constitutes the fixed part 9 of said contact grip 8 whereas the other branch 14 extends 5 in a parallel direction to the first branch 13. The screw 6 and tunnel 5 are fitted in the case B in such a way that tightening the screw 6 causes downward movement of the screw 6 and upward movement of the tunnel 5. A spring 24 in the form of a tile located in an opening of the case and pressing against the screw head is designed to bias the screw to the up position and to keep the hole for insertion of the tooth open. 10 In figure 1, the terminal screw 6 is in the unclamped position and, being in the up position, it allows the tooth 15 of the comb 3 to be inserted in a hole 23 situated inside the contact grip 8. Switchgear comprising this type of terminal are fed by the comb 3, the current being input to the connecting terminal strips 2 of the unit by the teeth 15 of the comb 3. When the supply comb 3 has to be fed by a cable 4, as illustrated in figure 2, this cable is inserted in 15 the hole 16 situated between the first branch 14 of the terminal strip 2 and the tunnel 5 and the terminal screw 6 is clamped, resulting in the screw 6 being inserted in the above mentioned hole 12 of the contact grip 8. The terminal screw 6 presses on the tooth 15 and tightening the screw 6 moves the tunnel 5 upwards. This results in the tooth 15 being clamped between the end of the screw 6 and the terminal strip 2 (first branch 13) and the 20 cable 4 being clamped between the terminal strip 2 (second branch 14) and the tunnel 5. According to the embodiment illustrated in figures 3 and 4, and as illustrated in figure 8, the terminal I comprises a tunnel 5, a screw 6 clamped in the top part 11 of the tunnel 5, a contact grip 8 comprising a fixed part 9 and a movable part 10, and a conducting intermediate part 7 comprising a U-shaped part electrically connected to the connecting 25 terminal strip 2. The U-shaped part comprises two branches 13a, 14a clamped one against the other, the fixed part 9 of the contact grip 8 being clamped between these branches. The tunnel 5 is situated inside the contact grip 8. The terminal also comprises a spring in the form of a serpentine 24, placed between the case and the tunnel and serving the purpose of biasing the tunnel to the down position so as to keep the hole for the comb tooth open. The 30 presence of a clamp 25 comprising a part placed inside the tunnel can also be noted. In figure 3, the screw 6 is unclamped, the hole 16 for insertion of the cable is open, and a tooth 15 can be inserted in the hole 23 inside the contact grip 8 between the conducting 6 intermediate part 7 (first branch 13a) and the tunnel 5. The current then flows through the comb 3, via the teeth 15, and through the intermediate part 7 in the direction of the connecting terminal strip 2. In figure 4, the screw 6 is unclamped, and a cable 4 has been inserted in the hole 16 5 situated between the end of the screw 6 and the conducting intermediate part 7 (branch 14a). When the screw 6 is tightened, the latter presses on the clamp 25 then the cable 4 and moves the tunnel 5 upwards, which tunnel is clamped between the end of the screw 6 by means of the above-mentioned clamp 25 and the conducting intermediate part 7 (branch 14a), the tooth 15 of the comb 3 being clamped between the intermediate part 7 (branch 10 13a) and the tunnel 5. In figure 5, the terminal comprises a screw 6 and a tunnel 5, the screw 6 being screwed into the top part 11 of the tunnel 5, a contact grip 8 comprising a fixed element 9 and a movable element 10, said movable element 10 comprising a hole 17 through which the head of the screw 18 passes, and a conducting intermediate part 7 in the shape of a closed U. This 15 intermediate part comprises a base 19, two wings 20, 21 and a part 22 closing the U constituting the fixed element 9 of the contact grip 8. The screw 6 passes through the contact grip 8 and the tooth 15 and engages in the tunnel 5 and moves the latter. The tunnel is movable in translation in a direction parallel to the axis of the screw. This terminal also comprises a return spring 24 in the form of a blade securedly fixed in 20 translation to the screw and fixed in the case. This spring 24 serves the purpose of biasing the screw upwards and of keeping the opening of the terminal open for a tooth to be inserted. In figure 5, the screw 6 is unclamped, and this screw being in the up position, the tooth 15 of the comb 3 can be inserted in the hole 23 provided in the contact grip 7 and clamped. 25 In figure 6, the tooth 15 is inserted in the contact grip 7 and a cable 4 is inserted in the space 16 situated between the intermediate part 7 (base 19) and the tunnel 5. When the screw 6 is tightened, the screw head 18 passes through the movable part 10 of the contact grip 8 and clamps the tooth 15 against the conducting intermediate part 7. When the screw 6 is tightened, the tunnel 5 is moved upwards resulting in the cable 4 being clamped 30 between the intermediate part 7 (base 19) and the tunnel 5. According to the embodiment illustrated in figures 10 and 11, the connection terminal I is of the screw and movable tunnel type, the screw 6 is screwed into the tunnel 11, said tunnel 7 11 comprising three openings respectively for passage of a tooth 15, of the terminal strip 2 and of a cable 4, tightening the screw 6 causing the tunnel I I to be moved upwards, this movement of the tunnel II resulting in the cable 4 being clamped against the terminal strip 2 and the tooth 15 being clamped against said terminal strip 2, the end of the tooth 15 being 5 designed to be inserted in the contact grip 8, said contact grip 8 being situated outside the tunnel 11. In this embodiment, the current coming from the cable flows through the terminal strip and flows in the tooth without flowing through the contact grip. 10 In all these embodiments, the switchgear unit whose terminal accommodates the cable receives the whole of the current via the cable feeding the comb, and the current flows from the cable to the tooth by clamping. By means of the invention, an electrical connection terminal and an electrical switchgear 15 unit comprising same have therefore been achieved enabling an electrical switchgear unit to be connected to a connecting bar without screwing, the terminal also being able to accommodate a cable which then requires traditional clamping, in a small volume, without this requiring over-dimensioning of the contact grip. This object is achieved by the fact that, in the case of connection to a comb, the tooth is gripped via a contact grip, and when a 20 cable is inserted in the terminal to feed the comb, the assembly formed by the cable and tooth is clamped via a clamping terminal electrically relieving the contact grip. By means of the invention, the current flows directly from the connection to the connecting terminal strip of the switchgear unit and the contact grip no longer has to withstand the feeder current from the other feeders of the row. In the case of feed tap-off from a unit, the 25 contact grip does not have to withstand the feeder current and the tap-off current. The quality of the contact no longer depends on the contact grip. In the case where a wiring error occurs creating a short-circuit between two phases and between two teeth of the same comb, the quality of the direct contact on the terminal strip prevents damage and welding before the protection of the circuit breakers situated up-line 30 is activated.

8 Naturally, the invention is not limited to the embodiments described and illustrated which have been given for example purposes only. On the contrary, the invention encompasses all the technical equivalents of the means described as well as combinations thereof if the latter are performed according to the spirit of the invention.

Claims

1. Electrical connection terminal for an electrical switchgear unit designed to electrically connect the terminal strip of said unit to a connecting comb and/or to an electrical power supply cable, including a U-shaped contact grip including a fixed part 5 and a movable part, said contact grip being electrically connected to said terminal strip and designed to grip a tooth of said comb in the connected position, and a clamping terminal designed, in the clamping position, to clamp a cable against said connecting terminal strip of the unit, wherein it includes a means for electrically connecting the cable, the tooth and the terminal strip by clamping the tooth against the terminal strip in the 10 clamping position of the terminal, the tooth being clamped between the fixed part of the contact grip and the movable part of said contact grip in such a way that the current coming from the cable flows through the terminal strip and flows in the tooth without flowing through the movable part of the contact grip.

2. Connection terminal according to claim 1, wherein it includes a conducting 15 intermediate part electrically connected to the terminal strip and in that in the clamping position of the tooth, said tooth is clamped against the intermediate part by the above mentioned means.

3. Connection terminal according to claim 2, wherein the intermediate part forms an integral part of the fixed part of the contact grip. 20

4. Connection terminal according to any one of the claims 1 to 3, wherein the terminal is of the type including a tunnel and a movable screw and wherein the hole for insertion of the cable is situated between the tunnel and the contact terminal strip and the hole for insertion of the tooth is situated between the terminal strip and the end of the screw, so that when the connection operation is performed, the cable is clamped between 25 the tunnel and the terminal strip and the tooth is clamped between the terminal strip and the end of the screw.

5. Connection terminal according to claim 4, wherein the foot of the screw passes through a hole provided in the movable part of the contact grip. 10

6. Connection terminal according to claim 2 or 3, wherein the terminal is of the type including a tunnel and a movable screw, the hole for insertion of the cable being situated between the connecting terminal strip and the end of the screw and the hole for insertion of the tooth being situated between the tunnel and the intermediate part so that in the 5 clamping position of the terminal, the cable is clamped between the terminal sirip and the end of the screw and the tooth is clamped between the tunnel and the intermediate part.

7. Connection terminal according to claim 6, wherein the intermediate part includes a U-shaped part, including two branches folded against one another, the two branches of the U clamping the fixed part of the contact grip, the cable being clamped between one of the 10 branches of the intermediate part and the screw and the tooth being clamped between the other branch of the intermediate part and the tunnel.

8. Connection terminal according to claim 2 or 3, wherein the terminal is of the type including a tunnel and a movable screw, the hole for insertion of the cable being situated between the intermediate part and the tunnel and the hole for insertion of the tooth being 15 situated between the intermediate part and the screw so that in the clamping position of the terminal, the cable is clamped between the intermediate part and the tunnel and the tooth is clamped between the intermediate part and the screw head.

9. Connection terminal according to claim 8, wherein the screw head passes through a hole provided in the movable part of the contact grip, the head of the screw clamping the 20 tooth against the intermediate part, and the tunnel clamping the cable against the intermediate part in the clamping position.

10. Connection terminal according to claim 8 or 9, wherein the intermediate part includes a part in the shape of a closed U the branches whereof constituting the small sides are folded towards one another and clamped respectively against the cable and the 25 tooth when the clamping operation of the terminal is performed, rotation of the screw moving the tunnel. 11

11. Connection terminal according to any one of the claims 1 to 3, wherein it includes a means for electrically connecting the cable, the tooth and the terminal strip by clamping of the tooth against the terminal strip in the clamping position of the terminal in such a way that the current coming from the cable flows through the terminal strip and flows in 5 the tooth without flowing through the contact grip.

12. Connection terminal according to claim 11, wherein it is of the type including a screw and a movable tunnel, that the screw is screwed into the tunnel, said tunnel including three openings respectively for passage of a tooth, of the terminal strip and of a cable, tightening of the screw causing upward movement of the tunnel, this movement of 10 the tunnel resulting in the cable being clamped against the terminal strip and the tooth being clamped against said terminal strip, the end of the tooth being designed to be inserted in the contact grip, said contact grip being situated outside the tunnel.

13. Electrical switchgear unit including a terminal according to any one of the foregoing claims. 15

14. Circuit breaker according to any one of the claims 1 to 12 including a terminal according to any one of the foregoing claims.

15. An electrical connection terminal substantially as herein before described with reference to the accompanying drawings. 20 SCHNEIDER ELECTRIC INDUSTRIES SAS WATERMARK PATENT & TRADE MARKS ATTORNEYS P28102AUOO