Low voltage switching device

Abstract

Described herein is a low voltage switching device including: one or more electric poles having one or more movable contacts and corresponding fixed contacts adapted to be coupled to or uncoupled from each other; a movable contact assembly including said movable contacts and a main supporting and operating shaft reversibly movable between a first contact position, at which said movable contacts and said fixed contacts are uncoupled, a second contact position, at which said movable contacts and said fixed contacts are coupled, and a third contact position, at which said movable contacts and said fixed contacts are coupled and kept pressed; an operating assembly including a handle mechanism having a handle adapted to be reversibly moved by a user or a motor operated actuator (MOE) between a first, open position and a second, closed position; and a driving assembly operatively connected to said operating assembly.

Claims

1. A low voltage switching device comprising: one or more electric poles, each electric pole comprising one or more movable contacts and one or more corresponding fixed contacts adapted to be coupled to or uncoupled from each other; a movable contact assembly comprising said movable contacts and a main supporting and operating shaft reversibly movable between a first contact position, at which said movable contacts and said fixed contacts are uncoupled, a second contact position, at which said movable contacts and said fixed contacts are coupled, and a third contact position, at which said movable contacts and said fixed contacts are coupled and kept pressed; an operating assembly comprising a handle mechanism having a handle adapted to be reversibly moved by a user or a motor operated actuator (MOE) between a first, open position and a second, closed position; and a driving assembly operatively connected to said operating assembly and to said movable contact assembly and comprising a kinematic chain and at least a driving spring, said driving assembly reversibly moving said movable contact assembly following a movement of said operating assembly from said first, open position to said second, closed position, and vice-versa, wherein said driving assembly comprises a latching mechanism which is operatively coupled to said operating assembly and to said movable contact assembly, said latching mechanism interacting with said movable contact assembly and latching said movable contact assembly in said first contact position during a first phase of the movement of said operating assembly between said first, open position and said second, closed position, then unlatching said movable contact assembly when said operating assembly is in an intermediate position between said first, open position and said second, closed position, thereby allowing quick passage of said movable contact assembly from said first contact position to said third contact position in which said movable contacts and said fixed contacts are coupled and kept pressed, wherein said latching mechanism comprises a latching element movable between a first latching position and a second un-latching position, wherein said latching element comprises a latching lever having a first end adapted to cooperate with a first operating lever connected to said handle mechanism and a second end having a latching portion adapted to cooperate with a first driving lever operatively connected to said movable contact assembly, and wherein said first end of said latching lever cooperates with a shaft hinged on said first operating lever and the latching portion of the second end of said latching lever cooperates with a shaft hinged on said first driving lever.

2. The low voltage switching device, according to claim 1, wherein said movable contact assembly is rotationally movable around an axis between said first, second and third contact positions, said movable contacts following said main supporting and operating shaft during rotational movement of said movable contact assembly from said first to said second contact position in which said movable contacts are coupled with the corresponding fixed contacts and remaining in such position while said main supporting and operating shaft moves from said second to said third contact position in which said movable contacts and said fixed contacts are coupled and kept pressed.

3. The low voltage switching device according to claim 1, wherein said latching element is moved from said first latching position to said second unlatching position by the first operating lever.

4. The low voltage switching device according to claim 3, wherein said first driving lever is rotationally hinged on a transverse axis and begins to move when an axis of the driving spring crosses said transverse axis.

5. The low voltage switching device according to claim 4, wherein a first end of said driving spring is fixed on a pivot point of said first operating lever, while a second end of said driving spring is fixed on a pivot point on said first driving lever which is operatively connected to the movable contact assembly.

6. The low voltage switching device according to claim 1, wherein said latching element is positioned on a fixed portion of said low voltage switching device.

7. A low voltage switching device comprising: one or more electric poles, each electric pole comprising one or more movable contacts and one or more corresponding fixed contacts adapted to be coupled to or uncoupled from each other; a movable contact assembly comprising said movable contacts and a main supporting and operating shaft reversibly movable between a first contact position, at which said movable contacts and said fixed contacts are uncoupled, a second contact position, at which said movable contacts and said fixed contacts are coupled, and a third contact position, at which said movable contacts and said fixed contacts are coupled and kept pressed; an operating assembly comprising a handle mechanism having a handle adapted to be reversibly moved by a user or a motor operated actuator (MOE) between a first, open position and a second, closed position; and a driving assembly operatively connected to said operating assembly and to said movable contact assembly and comprising a kinematic chain and at least a driving spring, said driving assembly reversibly moving said movable contact assembly following a movement of said operating assembly from said first, open position to said second, closed position, and vice-versa, wherein said driving assembly comprises a latching mechanism which is operatively coupled to said operating assembly and to said movable contact assembly and a second driving lever operatively coupled to said movable contact assembly, said latching mechanism interacting with said movable contact assembly and latching said movable contact assembly in said first contact position during a first phase of the movement of said operating assembly between said first, open position and said second, closed position, then unlatching said movable contact assembly when said operating assembly is in an intermediate position between said first, open position and said second, closed position, thereby allowing quick passage of said movable contact assembly from said first contact position to said third contact position in which said movable contacts and said fixed contacts are coupled and kept pressed, wherein said latching mechanism comprises a latching element movable between a first latching position and a second un-latching position, and wherein said latching element is fixed on a second operating lever connected to said handle mechanism, and wherein said latching element is provided with a latching portion that engages a round shaft hinged on the second driving lever in the first latching position.

8. The low voltage switching device according to claim 7, wherein said latching element is integrally made on the second operating lever.

9. The low voltage switching device according to claim 3, wherein a first end of said driving spring is fixed on a pivot point of said first operating lever, while a second end of said driving spring is fixed on a pivot point on said first driving lever which is operatively connected to the movable contact assembly.

Description

(1) FIG. 1 is a side view of a prior art embodiment of a pole for a low-voltage switching device in the open position;

(2) FIG. 2 is a side view of a prior art embodiment of a pole for a low-voltage switching device in during a closing operation;

(3) FIG. 3 is a side view of a prior art embodiment of a pole for a low-voltage switching device in the correct closed position;

(4) FIG. 4 is a side view of a prior art embodiment of a pole for a low-voltage switching device in an incorrect closed position;

(5) FIG. 5 is a side view of a first embodiment of a pole for a low-voltage switching device according to the invention, shown in the open position;

(6) FIGS. 6-9 are side views of a first embodiment of a pole for a low-voltage switching device according to the invention, representing different successive stages of the closing operation;

(7) FIG. 10 is a side view of a first embodiment of a pole for a low-voltage switching device according to the invention, shown in the closed position;

(8) FIGS. 11-16 are perspective views of the opening sequence of the pole for a low-voltage switching device which show the same successive stages represented in previous FIGS. 5-10;

(9) FIG. 17 is a side view of a second embodiment of a pole for a low-voltage switching device according to the invention, shown in the open position;

(10) FIGS. 18-19 are side views of a second embodiment of a pole for a low-voltage switching device according to the invention, representing different successive stages of the closing operation;

(11) FIG. 20 is a side view of a second embodiment of a pole for a low-voltage switching device according to the invention, shown in the closed position;

(12) FIG. 21 is an enlarged perspective view of a detail of a second embodiment of a pole for a low-voltage switching device according to the invention;

(13) FIGS. 22a-22c are respectively a perspective view, a side view and a front view of a component of a second embodiment of a pole for a low-voltage switching device according to the invention.

(14) Referring to the cited figures, the present invention relates to a switching device which is suitable to be installed in a low voltage electric switchgear panel or, more generally, in a low voltage electric power distribution grid. As a non-limiting example, the switching device may be an automatic MCCB (Molded Case Circuit Breaker) for low voltage applications, and the following description will be made with reference to a typical example of such kind of switching devices. Non limiting examples of low voltage switching devices, in which the present invention can be implemented, are described, e.g., in EP2382645, EP1883944, and EP3190600.

(15) The low voltage switching device generally comprises one or more electric poles 1, 100, which in turn comprise one or more movable contacts 2 and one or more corresponding fixed contacts 3 which are adapted to be coupled to or uncoupled from each other, according to well-known embodiments.

(16) The low voltage switching device further comprises a movable contact assembly 4 which comprises said movable contacts 2 and a main supporting and operating shaft 41. The movable contact assembly 4 is reversibly movable between a first contact position, at which said movable contacts 2 and said fixed contacts 3 are uncoupled, a second contact position, at which said movable contacts 2 and said fixed contacts 3 are coupled, and a third contact position, at which said movable contacts 2 and said fixed contacts 3 are coupled and kept pressed, as better explained hereinafter.

(17) Furthermore, the low voltage switching device also comprises an operating assembly 5 comprising a handle mechanism having a handle 51 adapted to be reversibly moved by a user or a motor operated actuator (MOE) between a first, open, position and a second, closed, position.

(18) The low voltage switching device is also provided with a driving assembly 6 which is operatively connected to said operating assembly 5 and to said movable contact assembly 4 and which comprises a kinematic chain 61 and at least a driving spring 62. The driving assembly 6 is adapted to reversibly move said movable contact assembly 4 following a movement of said operating assembly 5 from said open position to said closed position, and vice-versa.

(19) In general, the pole structure and the structure of the movable contact assembly, the operating assembly and the driving assembly of a low voltage switching device are well known in the art and will not be described with further details.

(20) One of the distinguishing features of the low voltage switching device of the present invention is given by the fact that said driving assembly 6 advantageously comprises a latching mechanism 7, 8 which is operatively coupled to said operating assembly 5 and to said movable contact assembly 4.

(21) As better explained hereinafter, the latching mechanism 7, 8 interacts with said movable contact assembly 4 and keep it latched in said first contact position during a first phase of the movement of said operating assembly 5 between said first, open, position and said second, closed, position. Then, the latching mechanism 7, 8 unlatches said movable contact assembly 4 when said operating assembly 5 is in an intermediate position between said first, open, position and said second, closed, position, thereby allowing the quick passage of said movable contact assembly 4 from said first contact position to said third contact position in which said movable contacts 2 and said fixed contacts 3 are coupled to each other and kept pressed against each other.

(22) According to a general typical embodiment of the low voltage switching device of the invention, the movable contact assembly 4 is rotationally movable around an axis 40 between said first, second and third contact position. The movable contacts 2 are operatively connected to said main supporting and operating shaft 41 and follow it during the rotational movement of said movable contact assembly 4 from said first to said second contact position in which said movable contacts 2 are coupled with the corresponding fixed contacts 3. Then, the movable contacts 2 remain in the coupled position with the fixed contacts 3 while the main supporting and operating shaft 41 slightly continues to rotates of a certain angle (pressing angle) and moves from said second to said third contact position in which said movable contacts 2 and said fixed contacts 3 are coupled to each other and kept pressed against each other.

(23) The driving spring 62 is preferably fixed on one or more elements of the kinematic chain including the operating assembly 5, the driving assembly 6 and the movable contact assembly 4, so that during actuation of the operating assembly 5 its axis 65 moves in a plane substantially perpendicular to the rotation axis 40 of the movable contact assembly 4. Advantageously, the latching mechanism 7, 8 generally comprises a latching element which is movable between a first latching position and a second un-latching position. Exemplary embodiments of latching element 71, 81 will be described hereinafter.

(24) Preferably, said latching element 71, 81 is moved from said first latching position to said second un-latching position by an operating lever 52, 53 which is connected to said handle mechanism. Moreover said latching element 71, 81 is conveniently provided with a latching portion 72, 82 which is adapted to cooperate with a driving lever 63, 64 operatively connected to said movable contact assembly 4.

(25) Preferably, one end of the driving spring 62 can be conveniently fixed on a pivot point of said operating lever 52, 53, while the other end is operatively connected to the movable contact assembly 4.

(26) In particular, the driving lever 63, 64 is rotationally hinged on a transverse axis 66, 67 which is substantially parallel to the axis of rotation of the movable contact assembly. The driving lever 63, 64 advantageously begins to move when the axis 65 of the driving spring 62 crosses said transverse axis 66, 67.

(27) In a preferred embodiment a first end of said driving spring 62 is fixed on a pivot point of said operating lever 52, 53, while a second end of said driving spring 62 is fixed on a pivot point on said driving lever 63, 64 which is operatively connected to the movable contact assembly 4.

(28) The functioning of a first exemplary embodiment of a low voltage switching device according to the invention will be now described with reference to FIGS. 5-10 and 11-16.

(29) In such embodiment, the low voltage switching device is provided with a latching element 71 which is positioned on a fixed portion of said low voltage switching device. In particular, the latching element is hinged on a shaft which has a fixed position inside the switching device. Said latching element 71 comprises a latching lever which has a first end 73 adapted to cooperate with a first operating lever 52 connected to said handle mechanism and a second end 74 which has a latching portion 72 adapted to cooperate with a first driving lever 63 operatively connected to said movable contact assembly 4. The first driving lever 63 is rotationally hinged on a transverse axis 66 parallel to the rotation axis 40 of the movable contact assembly 4. A first end of the driving spring 62 is fixed on a pivot point of said first operating lever 52, in this case a shaft 520, while a second end of said driving spring 62 is fixed on a pivot point on said first driving lever 63 which is operatively connected to the movable contact assembly 4.

(30) More in details, the first end 73 of said latching lever cooperates with a shaft 520 which is hinged on said first operating lever 52 and follows said first operating lever 52 during its movement under the action of the handle 51. The latching portion 72 of the second end 74 of said latching lever in turn cooperates with a shaft 630 which is hinged on said first driving lever 63, as explained hereinafter.

(31) With reference to FIGS. 5 and 11, in the open position of the switching device, the movable contacts 2 are spaced apart from the corresponding fixed contacts 3 and the operating handle 51 is in the open position.

(32) At the beginning of the closing operation (FIGS. 6 and 12), the operating handle is actuated and the operating assembly 5 starts moving. The latching portion 72 of the second end 74 of the latching lever urges against the shaft 630 hinged on the first driving lever 63, thereby preventing any movement thereof.

(33) As the closing operation proceeds (FIGS. 7 and 13), the first operating lever 52 of the operating assembly 5 gets closer to the latching element 71, while the first driving lever 63 is always kept in its position by the action of the latching portion 72 of the second end 74 of the latching lever on the shaft 630.

(34) At the un-latching point (FIGS. 8 and 14) the shaft 520 hinged on the first operating lever 52 urges against the first end 73 of the latching element determining its rotation (clockwise in the figures). As a consequence, the latching portion 72 of the second end 74 of the latching element 71 is moved away from the shaft 630, thereby freeing the first driving lever 63 which from this moment is free to move under the action of the spring 62. As previously explained, the unlatching of the first driving lever 63 takes place substantially when the axis 65 of the driving spring 62 crosses said transverse axis 66.

(35) The first driving lever 63 is operatively coupled to the movable contact assembly 4 which is therefore now free to rotate and bring the movable contacts 2 in the contact position of FIGS. 9 and 15, where they are operatively coupled to the corresponding fixed contacts. In this situation, the main supporting and operating shaft 41 continues to rotates of a certain angle (pressing angle) and moves to the third contact position, shown in FIGS. 10 and 16. In such position, the movable contacts 2 and the fixed contacts 3 are coupled to each other and kept pressed against each other, while the main supporting and operating shaft 41 is extra-rotated with respect to them by a suitable pressing angle.

(36) The functioning of a second exemplary embodiment of a low voltage switching device according to the invention will be now described with reference to FIGS. 17-20, will some details of a component of such embodiment will be described with reference to FIGS. 21 and 22a-22c.

(37) In such embodiment, the low voltage switching device is provided with a latching element 81 which is positioned on a movable part of said operating assembly 5. In particular, said latching element 81 is advantageously fixed on a second operating lever 53 which is connected to the handle mechanism of the switching device.

(38) With reference to FIGS. 22a-22c, in a preferred embodiment of the present invention, the latching element 81 is integrally made on one of the operating lever 53 of the operating assembly 5 which is connected to said handle actuator 51.

(39) The latching element 81 is conveniently provided with a latching portion 82 which is adapted to cooperate with a second driving lever 64 operatively connected to said movable contact assembly 4. The second driving lever 64 is rotationally hinged on a transverse axis 67 parallel to the rotation axis 40 of the movable contact assembly 4. A first end of the driving spring 62 is fixed on a pivot point of said second operating lever 53, while a second end of said driving spring 62 is fixed on a pivot point on said second driving lever 64 which is operatively connected to the movable contact assembly 4.

(40) More in details, the latching element 81 is integrally made on the second operating lever 53 and its movement is therefore guided by the movement of said second operating lever 53 during its movement under the action of the handle 51. The latching portion 82 of the latching element 81 in turn cooperates with a shaft 640 which is hinged on said second driving lever 64, as explained hereinafter.

(41) With reference to FIG. 17, in the open position of the switching device, the movable contacts 2 are spaced apart from the corresponding fixed contacts 3 and the operating handle 51 is in the open position, while the shaft 640 rest on the latching portion 82 of the latching element 81.

(42) As the closing operation proceeds (FIG. 18), the second operating lever 53 of the operating assembly 5 moves and so does the latching element 81 solidly fixed to it. During this initial movement, the latching portion 82 of the latching element 81 slides on the shaft 640 hinged on the second driving lever 64, thereby preventing any movement thereof.

(43) At the un-latching point shown in FIG. 19 the shaft 640 hinged on the second driving lever 64 is freed, thereby freeing the second driving lever 64 which from this moment is free to move under the action of the spring 62. Also in this case, the unlatching of the second driving lever 64 takes place substantially when the axis 65 of the driving spring 62 crosses said transverse axis 67.

(44) The second driving lever 64 is operatively coupled to the movable contact assembly 4 which is therefore now free to rotate and bring the movable contacts 2 and the main supporting and operating shaft 41 to the third contact position, shown in FIG. 20. In such position, the movable contacts 2 and the fixed contacts 3 are coupled to each other and kept pressed against each other, while the main supporting and operating shaft 41 is extra-rotated with respect to them by a suitable pressing angle.

(45) A detailed view of the movement and trajectory of the latching element 81 with respect to the second driving lever 64 and the corresponding shaft 640 is represented in FIG. 21.

(46) It is clear from the above description that the low voltage switching device of the present invention, fully achieve the intended aims and solved the above-highlighted problems.

(47) In practice, as previously explained, the presence of the latching mechanism allows to achieve always the conditions of quick opening manoeuvre irrespective of the speed of actuation of the operating handle, since the dynamic of the closing operation is always independent from the dynamic of actuation of the operating assembly.

(48) Indeed, the main supporting and operating shaft is always provided with the proper kinetic energy so as to be able to carry out the contacts coupling and to reach the proper pressing angle thereby ensuring the proper pressing action on the contacts when the switching device is the closed condition.

(49) Although being applicable to a broad range of low voltage switching devices, the present invention is particularly suitable in the field of Molded Case Circuit Breakers for low voltage applications.

(50) 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.