Low voltage contact assembly

Abstract

A low voltage contact assembly including a rotating support having a body adapted to rotate around a rotation axis and supporting at least a first couple of movable contacts that can be coupled to/uncoupled from corresponding first fixed contacts by rotation around said rotation axis. The first couple of movable contacts include a first and a second movable contacts housed in the rotating support. The low voltage assembly further includes a pressure exerting device having a pressing bar operatively coupled to the first and second elongated contact body and transversally placed with respect to the rotation plane of the first and second elongated contact bodies.

Claims

1. A low voltage contact assembly comprising a rotating support having a body adapted to rotate around a rotation axis and supporting at least a first couple of movable contacts that can be couple to/uncoupled from corresponding first fixed contacts by rotation around said rotation axis, said first couple of movable contacts comprising a first and a second movable contacts housed in said rotating support and each having a corresponding first and second elongated contact body with a contact end protruding from said rotating support, said first and second elongated contact bodies lying parallel to each other in a rotation plane substantially perpendicular to said rotation axis, said low voltage assembly comprising a pressure exerting device having a pressing bar operatively coupled to said first and second elongated contact body and transversally placed with respect to said rotation plane of said first and second elongated contact bodies, and a first and a second elastic elements positioned at opposite ends of said pressing bar, said pressing bar comprising a first and a second operating surface each comprising a corresponding first and second pressing surface protruding from said pressing bar and respectively acting on said first and second elongated contact body, wherein said first and second pressing surface are cam-shaped surfaces symmetrically protruding from said pressing bar and wherein said first and second elastic elements each have a first end fixed on said rotating support and a second end acting on said pressing bar.

2. The low voltage contact assembly, according to claim 1, wherein said first and second pressing surface are curved surfaces symmetrically protruding from said pressing bar.

3. The low voltage contact assembly, according to claim 1, wherein said first and second pressing surface are curved surfaces asymmetrically protruding from at least a portion of said pressing bar.

4. The low voltage contact assembly, according to claim 1, wherein said pressing bar is a substantially cylindrical bar transversally positioned in said rotating support with respect to said first and second elongated contact bodies.

5. The low voltage contact assembly, according to claim 1, wherein said pressing bar comprises a first and a second seat for said second end of said first and second elastic elements, respectively.

6. The low voltage contact assembly, according to claim 1, wherein said first and second elastic elements respectively comprise a first and a second spring each having a first end fixed on said rotating support and a second end acting on said pressing bar.

7. The low voltage contact assembly, according to claim 1, wherein said pressing bar and said first and second elastic elements of said pressure exerting device are a single body.

8. The low voltage contact assembly, according to claim 1, further comprising a second couple of movable contacts that can be coupled to/uncoupled from corresponding second fixed contacts by rotation around said rotation axis, said second couple of movable contacts comprising a third and a fourth movable contacts housed in said rotating support and each having a corresponding third and fourth elongated contact body with a contact end protruding from said rotating support, said third and fourth elongated contact bodies lying parallel to each other in a rotation plane substantially perpendicular to said rotation axis.

9. The low voltage contact assembly, according to claim 8, wherein said first and second couple of movable contacts are identical to each other and symmetrically positioned with respect to said rotation axis.

10. The low voltage contact assembly, according to claim 9, wherein said first and third elongated contact bodies are made in a single piece and said second and fourth elongated contact bodies are made in a single piece.

11. The low voltage contact assembly, according to claim 8, wherein said first and third elongated contact bodies are made in a single piece and said second fourth elongated contact bodies are made in a single piece.

12. A low voltage switching pole comprising the low voltage contact assembly according to claim 1.

13. A low voltage switching device comprising the low voltage contact assembly according to claim 1.

14. A low voltage circuit breaker comprising the low voltage contact assembly according to claim 1.

15. A low voltage contact assembly comprising a rotating support having a body adapted to rotate around a rotation axis and supporting at least a first couple of movable contacts that can be couple to/uncoupled from corresponding first fixed contacts by rotation around said rotation axis, said first couple of movable contacts comprising a first and a second movable contacts housed in said rotating support and each having a corresponding first and second elongated contact body with a contact end protruding from said rotating support, said first and second elongated contact bodies lying parallel to each other in a rotation plane substantially perpendicular to said rotation axis, said low voltage assembly comprising a pressure exerting device having a pressing bar operatively coupled to said first and second elongated contact body and transversally placed with respect to said rotation plane of said first and second elongated contact bodies, and a first and a second elastic elements positioned at opposite ends of said pressing bar, said pressing bar comprising a first and a second operating surface each comprising a corresponding first and second pressing surface protruding from said pressing bar and respectively acting on said first and second elongated contact body, wherein said first and second pressing surface are cam-shaped surfaces protruding from said pressing bar.

16. A low voltage contact assembly comprising a rotating support having a body adapted to rotate around a rotation axis and supporting at least a first couple of movable contacts that can be couple to/uncoupled from corresponding first fixed contacts by rotation around said rotation axis, said first couple of movable contacts comprising a first and a second movable contacts housed in said rotating support and each having a corresponding first and second elongated contact body with a contact end protruding from said rotating support, said first and second elongated contact bodies lying parallel to each other in a rotation plane substantially perpendicular to said rotation axis, said low voltage assembly comprising a pressure exerting device having a pressing bar operatively coupled to said first and second elongated contact body and transversally placed with respect to said rotation plane of said first and second elongated contact bodies, and a first and a second elastic elements positioned at opposite ends of said pressing bar, said pressing bar comprising a first and a second operating surface each comprising a corresponding first and second pressing surface protruding from said pressing bar and respectively acting on said first and second elongated contact body, wherein said first and second pressing surface are curved surfaces asymmetrically protruding from at least a portion of said pressing bar.

Description

(1) Further features and advantages of the present invention will be more clear from the description of preferred but not exclusive embodiments of the low voltage contact assembly of the present invention, and in particular of a low voltage contact assembly with a double movable contact, shown by way of examples in the accompanying drawings, wherein:

(2) FIG. 1 is a side view of a first embodiment of a low voltage contact assembly according to the present invention;

(3) FIG. 2 is a perspective view of a first embodiment of a low voltage contact assembly according to the present invention;

(4) FIG. 3 is a side view of a second embodiment of a low voltage contact assembly according to the present invention;

(5) FIG. 4 is a perspective view of a second embodiment of a low voltage contact assembly according to the present invention;

(6) FIG. 5 is a schematic view of an embodiment of a low voltage contact assembly according to the present invention, shown in the closed position under normal conditions;

(7) FIG. 6 is a schematic view of an embodiment of a low voltage contact assembly according to the present invention, shown in the closed position under contact wearing conditions;

(8) FIG. 7 is a schematic view of an embodiment of a conventional low voltage contact assembly, shown in the closed position under normal conditions;

(9) FIG. 8 is a schematic view of an embodiment of a conventional low voltage contact assembly, shown in the closed position under contact wearing conditions;

(10) FIG. 9 is a front view of a first embodiment of a component of a low voltage contact assembly according to the present invention;

(11) FIG. 10 is a front view of a second embodiment of a component of a low voltage contact assembly according to the present invention;

(12) FIG. 11 is a front view of a third embodiment of a component of a low voltage contact assembly according to the present invention;

(13) FIG. 12 is a front view of a fourth embodiment of a component of a low voltage contact assembly according to the present invention;

(14) FIG. 13 is a perspective view of a low voltage switching pole including a low voltage contact assembly according to the present invention;

(15) FIG. 14 is a perspective view of a low voltage circuit breaker including a low voltage contact assembly according to the present invention.

(16) With reference to the attached figures a low voltage contact assembly 1, 10 of the present invention in its more general definition comprises a rotating support 2 which has a body 21 adapted to rotate around a rotation axis 100.

(17) In the single interruption configuration of FIGS. 1 and 2, the body 21 supports at least a first couple 11 of movable contacts that can be coupled to/uncoupled from corresponding first fixed contacts 51 by rotation around said rotation axis 100.

(18) In particular, the first couple 11 of movable contacts normally comprises a first 61 and a second 62 movable contacts which are housed in said rotating support 2. According to known embodiments, the first 61 and a second 62 movable contacts have a corresponding first 71 and second 72 elongated contact body with a contact end 711, 721 protruding from the rotating support 2.

(19) The first 71 and second 72 elongated contact bodies are positioned parallel to each other in a rotation plane which is substantially perpendicular to said rotation axis 100 and can rotate between a closed position (shown in the figures) and an open position (not shown).

(20) With reference to FIGS. 3 and 4, in case of double interruption applications, the low voltage contact assembly 10, according to the present invention, comprises a second couple 12 of movable contacts that can be coupled to/uncoupled from corresponding second fixed contacts 52 by rotation around said rotation axis 100.

(21) The second couple 12 of movable contacts is also supported by the body 21 of the rotating support 2 and comprises a third 63 and a fourth 64 movable contacts which are housed in said rotating support 2.

(22) The third 63 and fourth 64 movable contacts each has a corresponding third 73 and fourth 74 elongated contact body with a contact end 731, 741 that protrudes from said rotating support 2.

(23) The third 73 and fourth 74 elongated contact bodies are positioned parallel to each other in a rotation plane which is substantially perpendicular to said rotation axis 100, and can rotate together with the first 71 and second 72 elongated contact bodies between a closed position (shown in the figures) and an open position (not shown).

(24) According to embodiments known for double interruption applications, in preferred embodiments of the low voltage contact assembly 10 the first 11 and second 12 couple of movable contacts are identical to each other and are symmetrically positioned with respect to said rotation axis 100, as shown in FIGS. 3 and 4.

(25) More in particular, according to embodiments known for double interruption applications, the first 71 and third 73 elongated contact bodies are conveniently made in a single piece and the second 72 and fourth 74 elongated contact bodies are also conveniently made in a single piece.

(26) One of the particular features of the low voltage assembly 1, 10 according to the present invention is given by the fact that it further comprises a pressure exerting device 30 having a pressing bar 31, 32, 33, 34 of possible different shapes that is operatively coupled to said first 71 and second 72 elongated contact body.

(27) As shown in the attached figures, the pressing bar 31, in typical embodiments of the low voltage assembly 1, 10, is transversally placed with respect to the rotation plane of said first 71 and second 72 elongated contact bodies, and in case of double interruption applications, it is transversally placed also with respect to the rotation plane of said third 73 and fourth 74 elongated contact bodies.

(28) The pressure exerting device 30 is further provided with a first 41, 411 and a second 42, 421 elastic elements which are positioned at opposite ends of said pressing bar 31, 32, 33, 34.

(29) A further particular features of the low voltage assembly 1, 10 according to the present invention is given by the fact that said pressing bar 31, 32, 33, 34 further comprising a first and a second operating surface each comprising a corresponding first 81, 811 and second 82, 821 pressing surface protruding from said pressing bar 31, 32, 33, 34.

(30) The first 81, 811 and second 82, 821 pressing surfaces respectively act on said first 71 and second 72 elongated contact body, so as to compensate possible variation of planarity in the contact surface regions by maintaining a substantially balanced pressing force the first 71 and second 72 elongated contact body.

(31) The behavior of the presently disclosed low voltage contact assembly is represented in the attached FIGS. 5 and 6, which respectively shows double movable contact arrangement according to the invention under normal conditions and under wearing conditions.

(32) With reference to FIG. 5, the low voltage contact assembly 10 according to the invention, comprise a couple of movable contacts having corresponding contact end 711 and 721 which can be coupled to/uncoupled from a corresponding fixed contacts 51. Under normal conditions and in the closed positions, the pressing bar 31 exert a uniform pressure generated by the springs 41 and 42 on the contact end 711 and 721.

(33) Differently from the situation of FIGS. 7 and 8, where the pressing bar is substantially cylindrical, in the low voltage contact assembly of the present invention the pressing bar 31 is provided with first 81 and second 82 pressing surfaces that protrudes from the pressing bar 31 and act on said first 71 and second 72 elongated contact body.

(34) As shown in FIG. 6, in case of, e.g., excessive or non-uniform wearing of the contacts, a situation of non-co-planarity is generated in correspondence of the contact surfaces between the movable contacts 711, 721 and the fixed contact 51. In such a case, the different heights due to the lack of planarity is compensated by the balancing effect of the first 81 and second 82 pressing surfaces having a rounded profile that allows keeping the pressure exerted by the pressing bar 31 is uniformly distributed on the movable contacts ends 711, 721, as shown by the arrows 310, thereby overcoming the problems of the known art.

(35) Typically, said first 41 and second 42 elastic elements each have a first end fixed on said rotating support 2 and a second end acting on said pressing bar 31.

(36) The first 41 and second 42 elastic elements can be for instance a first and a second spring each having a first end fixed on said rotating support 2 and a second end acting on said pressing bar 31.

(37) Preferably, as shown in FIG. 10, the pressing bar 32 can conveniently comprise a first 321 and a second 322 seat for housing said second end of said first 41 and second 42 elastic elements, respectively.

(38) The first 81 and second 82 pressing surface are generally curved surfaces protruding from the pressing bar.

(39) As shown in FIGS. 13-6, 9-10 and 12 said first 81 and second 82 pressing surface are curved surfaces symmetrically protruding from said pressing bar 31, 32, 34.

(40) Alternatively, as shown in FIG. 11, said first 811 and second 821 pressing surface can be cam-shaped surfaces protruding from said pressing bar 33, and, in general, the first 811 and second 821 pressing surface can be curved surfaces asymmetrically protruding from at least a portion of said pressing bar 33.

(41) In general, in the pressure exerting device 30 the pressing bar 31, 32, 33 and the first 41 and second 42 elastic elements are made as separate elements operatively coupled. However, as shown in FIG. 12, I a possible embodiment of a low voltage contact assembly according to the invention said pressing bar 34 and said first 411 and second 421 elastic elements of said pressure exerting device 30 can be made as a single body.

(42) In a further aspect, with reference to FIG. 13, the present invention also relates to a low voltage switching pole 101 which comprises a low voltage contact assembly 1, 10 as previously disclosed.

(43) Furthermore, with reference to FIG. 14, the present invention also relates to a low voltage switching device, and in particular a voltage circuit breaker 102 which comprises a low voltage contact assembly as previously disclosed. In the embodiment shown, the circuit breaker 102 comprises a casing 103 having a cover 104. Inside the casing 103 there are a number of low voltage poles which house a corresponding low voltage contact assembly as disclosed herein.

(44) It is clear from the above that the low voltage switching device of the present invention allows solving the previously underlined technical problems.

(45) Several variations can be made to the low voltage switching device thus conceived, all falling within the scope of the attached claims. In practice, the materials used and the contingent dimensions and shapes can be any, according to requirements and to the state of the art.