Device for switching electric current

Abstract

The device (2) for switching electric current with separable electrical contacts comprises a switching mechanism (10), the mechanism comprising: a switching shaft (20), which is connected to a movable electrical contact (6); a trip hook (40), which is pivotally mounted on a fixed support of the mechanism; a connection system (22), which connects the switching shaft to the trip hook; the connection system (22) comprises a first pair (42) of connecting rods pivotally mounted on the trip hook and a second pair (44) of connecting rods mounted to pivot with a crank (24) of the switching shaft. The first connecting rod is connected to the second connecting rod by a single articulation axis (68), the articulation axis (68) forming a pivot connection between the first connecting rod and the second connecting rod.

Description

Technical Field

[0001] The invention relates to a device for switching electric current.

[0002] The invention relates in particular to the field of electrical switching devices for interrupting electric current, such as circuit breakers or switches. Background Art

[0003] A switching device with separable contacts includes a switching mechanism using energy accumulation, the function of which is to move the electrical contacts of the device between an open state and a closed state, for example in response to a trip device or a user's action.

[0004] An example of such a mechanism is described in FR-2985600-B1.

[0005] For example, the pivoting mobile electrical contact is moved by a switching shaft which is mechanically coupled to the trip hook via a connection system. To close the contacts, an energy accumulator comprising a spring is actuated to move the connection system.

[0006] The switching mechanism is therefore subject to a great deal of mechanical stress at each opening and closing of the contacts.

[0007] Such mechanisms have long been satisfactory. However, in some modern applications, it is desirable to have a switching mechanism with improved durability, for example in order to increase the number of opening and closing cycles permitted over the useful life of the product.

[0008] Therefore, there is a need for an apparatus for switching electric current wherein the switching mechanism has improved reliability. Summary of the invention

[0009] To this end, one aspect of the invention relates to a device for switching an electric current, the device comprising separable fixed and movable electrical contacts and a mechanism capable of switching the contacts between a closed state and an open state, the mechanism comprising:

[0010] a switching shaft coupled to the movable electrical contact;

[0011] a trip hook pivotally mounted on a fixed support of the mechanism;

[0012] a connection system that couples the switching shaft to the trip hook;

[0013] The connection system comprises a first pair of connecting rods and a second pair of connecting rods, the first connecting rod being pivotably mounted on the trip hook, the second connecting rod being mounted to pivot with the crank of the switching shaft, and the first connecting rod being connected to the second connecting rod by a single articulation axis, the articulation axis forming a pivot connection between the first connecting rod and the second connecting rod. The articulation axis combines the functions of ensuring the pivot connection and maintaining the spacing of the paired rods.

[0014] Thus, the reliability of the switching mechanism is improved, in particular by means of a better durability of the connection system.In particular, by using a connection axis, the risk of an accidental breakage of the pivot connection between the first link and the second link is reduced.

[0015] According to some advantageous but non-mandatory aspects, such a device may incorporate one or more of the following features, alone or in any technically permissible combination:

[0016] Each end of the articulation axis comprises a head, each head comprising an overwidth forming a retaining portion for preventing the first link and the second link from being separated from each other.

[0017] The articulation axis comprises a peripheral groove formed at the bottom of each head.

[0018] The peripheral groove has a depth between 0.2 mm and 0.6 mm, preferably equal to 0.4 mm.

[0019] - The height of each head is less than or equal to 5 mm, preferably between 2 mm and 3 mm.

[0020] The maximum width of the head is between 9 mm and 10 mm, preferably between 9.6 mm and 9.8 mm.

[0021] The articulation axis is mounted in the connection system so as to have a radial play less than or equal to 0.1 mm for the first and second connecting rods.

[0022] Each first link is mounted on a first region of the articulation axis having a first diameter, and each second link is mounted on a second region of the articulation axis having a second diameter different from the first diameter.

[0023] The articulation axis is made of a steel alloy, for example a steel alloy with chromium and molybdenum.

[0024] The articulation axis is formed from a one-piece component.

[0025] - Each second link has a shape bent into an arc shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The invention will be better understood and further advantages thereof will become more apparent from the following description of one embodiment of the electrical device, given by way of example only, and with reference to the accompanying drawings, in which:

[0027] Figure 1 Schematically illustrates a switching device with separable contacts, shown in a mid-section plane, comprising a switching mechanism according to some embodiments of the present invention;

[0028] Figure 2The formation is schematically shown in an isometric perspective view Figure 1 A connection system of a portion of a switching mechanism;

[0029] Figure 3 The side view indicated by arrow III schematically shows Figure 2 connection system;

[0030] Figure 4 The longitudinal cross-section diagram schematically shows Figure 2 The axis of the connection system. DETAILED DESCRIPTION

[0031] Figure 1 A part of an electrical switching device 2 for interrupting an electric current, such as a circuit breaker or a contactor, is shown. The electric current is switched in the air via separable electrical contacts.

[0032] According to some examples, the device 2 is a low voltage high intensity multi-pole circuit breaker.

[0033] The device 2 comprises a fixed electrical contact 4 and a movable electrical contact 6 which, in some examples, supports a pivotably mounted contact finger 8 arranged opposite the fixed contact 4. The contacts 4 and 6 are connected to opposite electrical connection terminals of the device 2.

[0034] The movable contact 6 is reversibly movable between open and closed positions of the contact corresponding respectively to the electrically open and closed states of the device 2, for example by pivoting relative to the fixed frame of the device 2. In the present case, the axis of rotation of the movable contact 6 is indicated by reference X6.

[0035] The device 2 further comprises a switching mechanism 10 adapted to switch the contacts 4 and 6 between an open state and a closed state by moving the movable contact 6 between an open position and a closed position.

[0036] For example, the mechanism 10 may be controlled by a trip device 12 of the device 2 and / or by a manual control element such as a lever or button.

[0037] According to some embodiments, the device 2 is a multi-pole device suitable for interrupting a multi-phase current. The device 2 then comprises a plurality of poles, each pole being associated with an electrical phase and comprising a pair of contacts 4 and 6. As a variant, the device 2 is unipolar.

[0038] According to some embodiments, the mechanism 10 is a switching mechanism using mechanical energy accumulation. The working principle of a switching mechanism using this technology is described, for example, in FR-2985600-B1.

[0039] The mechanism 10 comprises in particular a switching shaft 20 which is coupled, in the present case by a pivoting link, to the movable contact 6. The shaft 20 is rotatably movable about its longitudinal axis relative to a fixed frame or fixed support of the device 2.

[0040] If the device 2 comprises a plurality of poles, the shaft 20 is common to all of these poles and is mechanically coupled to each movable contact 6 .

[0041] The mechanism 10 also comprises a trip hook 40 and a connection system 22 coupling the switching shaft to the trip hook. The connection system 22 is articulated, for example, by a pivot connection to an arm of a crank 24 supported by the shaft 20, as described below.

[0042] The mechanism 10 also includes an opening pawl 26 associated with a bolt 28 (also called a "half-moon").

[0043] The opening pawl 26 is mounted to pivot relative to the frame and cooperates with the trip hook 40. The spring 29 engages between firstly the shaft 20 and secondly an axis integral with the frame of the device 2.

[0044] The closing bolt 30 (also called "half-moon") and the intermediate rod 31 cooperate mechanically with an actuator (for example an electromagnetic actuator with a coil) controlled by the trip device 12 and / or with a manual control element. Figure 1 In FIG. 1 , the association between the trip device and the rod 31 is schematically shown by a rod, although in practice this mechanical cooperation can be produced in a completely different way.

[0045] The bolt 30 is also mechanically associated with a closing pawl 32 mounted so as to pivot relative to the frame.

[0046] Furthermore, the mechanism 10 comprises a mechanical energy accumulation device 34 comprising at least one spring. For example, the device 34 stores mechanical energy when the spring is compressed and releases this mechanical energy by the relaxation of the spring.

[0047] A drive mechanism 36, which in the present case comprises one or more connection parts that are hinged and / or mounted to pivot relative to the fixed frame, is mechanically coupled to the device 34. The drive mechanism 36 acts on the connection system 22 so as to impact it and push it into the closed position. In this way, by moving, the connection system 22 in turn drives the trip hook 40.

[0048] In the present case, the trip hook 40 is mounted so as to pivot relative to the frame and is articulated to the connection system 22 by a pivot connection.

[0049] For easier understanding of the present description, other components of the device 2 are neither shown nor described in detail.

[0050] In the embodiment shown, the pivoting and rotational movements of the elements of the mechanism 10 occur about rotation axes which are fixed relative to the frame and extend parallel to one another, in the present case perpendicularly to the Figure 1 In the image plane and parallel to the direction of axis X6.

[0051] An example of the operation of the mechanism 10 will now be briefly described.

[0052] exist Figure 1 In the stable open position shown, the device 34 is armed, that is, the spring is compressed and stores energy. The bolt 30 holds the closing pawl 32 in the first position.

[0053] To close the contacts 4 and 6 , the closing bolt 30 is tilted, for example by the action of the trip device 12 or a pushbutton, thereby releasing the closing pawl 32 .

[0054] The movement of the closing pawl 32 actuates the mechanical energy accumulation device 34, and the energy accumulated in the device 34 is released by the relaxation movement of the spring, and this actuates the connection system 22 with the aid of the drive mechanism 36, for example by striking it, so as to move the movable contact 6 through the shaft 20 until the movable contact 6 comes into contact with the fixed contact 4.

[0055] The connection system 22 continues to move toward its closed position until it passes a predetermined alignment position, referred to as a "dead point," in the forward direction, thereby urging the trip hook 40 and the opening pawl 26 to a stop position in which the connection system 22 is prevented from returning rearwardly.

[0056] The mechanism 10 is then in a stable closed position.

[0057] To reopen the device 2, the lock between the opening pawl 26 and the bolt 28 is broken, for example by moving the rod 31 by means of the actuator 12 or by manual action directly on the bolt 28. The opening pawl 26 pivots, thereby releasing the stop of the trip hook 40.

[0058] The connection system 22 is then no longer held in abutment by the hook 40 and can return to its initial position under the effect of the restoring force exerted by the spring 29. Once the connection system 22 has returned to the dead center position, the contact 6 is pushed towards its open position. The mechanism 10 returns to the stable open position.

[0059] Figure 2 and Figure 3 An example of a connection system 22 consistent with some embodiments of the present invention is shown.

[0060] The connection system 22 comprises a first pair of links 42 and a second pair of links 44 articulated to one another, on which pivot connections for articulation to the trip hook 40 and the shaft 20 are formed.

[0061] In the example shown, the trip hook 40 also has a hole 46 for receiving a pivot connection to the frame and a stop 48 which in the present case protrudes on both sides of the trip hook 40. For example, the trip hook 40 has a substantially flat shape.

[0062] According to some examples, in the closed position of the mechanism 10 as described above, the stopper 48 blocks the first pair of links 42, thereby blocking the position of the connection system 22. During the opening movement, the stopper 48 forces the first pair of links 42 to separate under the action of the spring 29 to return the connection system 22 to the open position.

[0063] The first pair of links 42 includes two similar or identical links 50 and 52 arranged parallel to each other. According to some examples, the links 50 and 52 have a planar shape.

[0064] A first end (in the present case, a lower end) of each link 50 and 52 is pivotably mounted on the trip hook 40 , more specifically on a distal end 54 of the trip hook 40 .

[0065] In the present case, the pivot connection is formed by a rigid axis 56 (such as a journal) extending perpendicularly to the links 50 and 52. Reference X56 denotes the axis of rotation associated with the pivot connection. In the present case, the axis X56 is parallel to the axis X6.

[0066] According to some examples, the connection system 22 may also comprise a ring 58 mounted between the links 50 and 52 on a spacer 59 which fixes the links 50 and 52 to each other. In the present case, the spacer 59 extends parallel to the axis X56.

[0067] For example, when energy is released by the device 34 , the spacer 59 and the ring 58 are struck by the drive mechanism 36 .

[0068] In the example of the mechanism 10 described above, the dead center position of the connection system 22 corresponds to a position where the pair of links 42 and 44 are aligned with each other along the same straight line. Compared to the pair of links 44 in other positions, the pair of links 42 is bent.

[0069] The second pair of links 44 includes two similar or identical links 60 and 62 arranged parallel to each other. According to some examples, the links 60 and 62 have a planar shape.

[0070] According to some optional but still advantageous embodiments, each second link 60 and 62 has a shape bent into an arc, which improves the distribution of mechanical stresses and increases the mechanical durability of the system 22 .

[0071] The first ends, in the present case the upper ends, of the connecting rods 60 and 62 are adapted to be pivotably mounted on the shaft 20 , more specifically on the arm of the crank 24 , in the present case in a hole formed in this arm of the crank 24 .

[0072] This pivot connection is formed by a rigid axis 64 extending perpendicularly to the links 60 and 62, preferably by projecting on the outer side relative to the links 60 and 62. Reference numeral X64 denotes the axis of rotation associated with this pivot connection. In the present case, axis X64 is parallel to axis X56. Rigid axis 64 is placed on said first end of the links 60 and 62.

[0073] According to some examples, the rigid axis 64 is permanently fixed to the links 60 and 62. In other words, the rigid axis 64 remains stationary relative to the links 60 and 62.

[0074] The links 60 and 62 forming the second pair of links 44 are kept at a distance from each other in the direction X64 to allow one end 66 of the trip hook 40 to pass between the links 60 and 62 .

[0075] This end 66 forms a protruding hook which cooperates with the opening pawl 26 , for example by abutting against the opening pawl 26 in the closed position.

[0076] The links 50 and 52 are connected to the links 60 and 62 by a single articulation axis 68 forming a pivot connection between the links 50 and 52 of the first pair 42 and the links 60 and 62 of the second pair 44. Reference X68 denotes a straight line providing the axis of rotation associated with this pivot connection.

[0077] The articulation axis 68 extends along this axis X68 , which is referred to below as “direction X68 ” in order to avoid any confusion with the articulation axis 68 .

[0078] According to some examples, the links 60 and 62 are arranged on both sides of the links 50 and 52 and contact the links 50 and 52 over a portion of their lengths. The link 50 is adjacent to the link 60, and the link 52 is adjacent to the link 62.

[0079] The pivot connection formed by the hinge axis 68 is formed at the other end of each link 50, 52, 60 and 62, that is to say at the second end of the links 50 and 52 and at the second end of the links 60 and 62. In fact, the second end of each link is opposite to the first end of said link.

[0080] As shown, the links 60 and 62 are interconnected at their second ends only by the axis 68. In other words, in order to maintain a constant spacing between the paired links 42 and 44, it is not necessary to add a fixed axis connecting the second ends of the links 60 and 62.

[0081] Thus, in the example shown, the pivot connection formed by the articulation axis 68 is located at the lower ends of the links 60 and 62 and at the upper ends of the links 50 and 52. In these examples, the articulation is thus formed substantially in the middle of the connection system 22.

[0082] like Figure 4 As shown, the articulation axis 68 comprises a body of elongated, preferably cylindrical shape. In the present case, the articulation axis 68 has a rotational symmetry about the direction X68. However, other shapes are also possible.

[0083] In fact, the respective ends of the links 50 , 52 , 60 and 62 comprise through holes allowing the passage of the body of the articulation axis 68 .

[0084] Preferably, each end of the articulation axis 68 includes a head 70 and 72 formed integrally with the body of the articulation axis 68 .

[0085] In the example shown, the head 70 projects from an outer side of the connecting rod 60 , while the head 72 projects from an outer side of the connecting rod 62 .

[0086] Preferably, but still optionally, the height (denoted by "h") of each head 70 and 72 measured perpendicular to the face of the connecting rod 60 or 62 from which the head extends is less than or equal to 5 mm, preferably between 2 mm and 3 mm.

[0087] Each head 70 and 72 comprises a widening forming a retaining portion to prevent the links 50 and 52 of the first pair 42 and the links 60 and 62 of the second pair from being separated from each other, ie in the direction X68 .

[0088] In other words, each head 70 , 72 is wider than the body of the articulation axis 68 .

[0089] For example, if the articulation axis 68 is cylindrical, the diameter of each head 70 , 72 is greater than the diameter of the body of the articulation axis 68 , for example at least 1.1 times the diameter of the body of the articulation axis 68 .

[0090] Articulation axis 68 allows a constant spacing to be maintained between links 50 and 52 and between links 60 and 62 even as connection system 22 moves.

[0091] As an illustrative example, the resistance of the link to a lateral torsion in the direction X68 is greater than or equal to 800 daN, represented by the minimum force required for such a torsion, relative to the other links at the articulation axis 68 .

[0092] According to some examples, the maximum width of the heads 70 , 72 , measured in the present case perpendicularly to the direction X68 , is between 9 and 10 mm, preferably between 9.6 and 9.8 mm.

[0093] For example, the radius R1 is between 4.5 mm and 5 mm, and the radius R2 is between 3 mm and 5 mm.

[0094] For example, each head 70 and 72 has a conical shape, the base of which is in contact with the body of the articulation axis 68 , the radius R2 of the base being strictly smaller than the radius R1 measured at the top of the heads 70 , 72 .

[0095] However, other shapes are possible, such as a cylindrical shape of constant diameter, but which is greater than the diameter of the body of the axis 68 .

[0096] Preferably, heads 70 and 72 are identical.

[0097] According to some examples, each link 50 and 52 is mounted on a first region of the articulation axis 68 having a first diameter D1, and each link 60 and 62 is mounted on a second region of the articulation axis 68 having a second diameter D2 different from the first diameter D1. For example, the diameter D1 is greater than the diameter D2. Thus, in the present case, the body of the articulation axis 68 comprises at least two regions of diameter D1 and at least two regions of diameter D2. For example, the diameter D1 is equal to 9.5 mm and the diameter D2 is equal to 9 mm.

[0098] These differently sized areas form receiving areas for the links that prevent the links from sliding along the articulation axis 68 during movement of the connection system 22. For example, the widening of the diameter between the second area and the first area prevents the links 60 and 62 from sliding toward the center of the articulation axis 68. This contributes to the stability of the connection system 22 and increases resistance to torsional forces.

[0099] The articulation axis 68 is preferably freely rotatable relative to the connecting rods 50 , 52 , 60 and 62 about a direction X68 .

[0100] For example, the articulation axis 68 is mounted in the connection system 22 so as to have a radial play with the connecting rods 50 , 52 , 60 and 62 that is less than or equal to 0.1 mm and greater than 0 mm.

[0101] In this case, the radial play is measured perpendicularly to the direction X68.

[0102] In particular, the radial play is selected in each receiving region based on the diameter of the through-hole of the respective connecting rod 50, 52, 60 and 62. For example, the connecting rods of the same pair of connecting rods 42, 44 have through-holes which have the same diameter.

[0103] In many embodiments, the articulation axis 68 is formed from a one-piece component.

[0104] According to some examples, the articulation axis 68 is made of metal. Preferably, the articulation axis 68 is made of a steel alloy, and more preferably of a steel alloy with chromium and molybdenum. Preferably, the steel alloy has been previously heat-treated throughout to obtain a hardness between 340 and 400 on the Vickers scale HV30.

[0105] Thus, the mechanical properties of the articulation axis 68 are improved, which increases the durability of the connection system 22 and reduces the risk of premature fracture, while providing the articulation axis 68 with sufficient rigidity so as not to induce undesired deformations in the pair of connecting rods 42 , 44 .

[0106] Optionally but still advantageously, the articulation axis 68 comprises a peripheral groove 74 formed at the bottom of each head 70 and 72 , preferably arranged concentrically with the direction X68 and flush with the face of the connecting rod 60 , 62 from which the head 70 or 72 projects.

[0107] The groove 74 makes it easier to obtain an axial play in the direction X68 between the articulation axis 68 and the connecting rods 50 , 52 , 60 and 62 of a desired value.

[0108] For example, the depth of the groove 74 measured perpendicularly to the direction X68 is between 0.2 mm and 0.6 mm, preferably equal to 0.4 mm.

[0109] Thanks to the embodiment of the invention, the reliability of the switching mechanism 10 is increased, in particular due to the better durability of the connection system 22. In particular, thanks to the use of the articulation axis 68, the risk of accidental breaking of the pivot connections between the links 50, 52, 60 and 62 is reduced, while allowing the pivoting movement of the pair of links 42 relative to the pair of links 44, which is necessary for the operation of the mechanism 10.

[0110] In particular, the hinge axis 68 immediately combines the functions of providing a pivot connection and maintaining a spacing between the pair of links 42 , 44 .

[0111] On the other hand, the use of the articulation axis 68 allows the connection system 22 to have a shape that makes it compatible with existing switching mechanisms, thereby enabling it to be used in a wide range of electrical switching devices without having to completely modify the architecture of the switching mechanisms of these devices.

[0112] Thus, better mechanical performance allows a higher level of durability to be achieved for the mechanism 10. The device 2 is thus able to withstand a greater number of mechanical opening and closing cycles during its useful life.

[0113] Thus, the device 2 may be advantageously used in critical applications requiring a high level of reliability, where the device may need to be used frequently, such as data centers or renewable energy production systems.

[0114] The embodiments and variants envisaged above can be combined to create new embodiments.

Claims

1. A switching device (2) for switching electric current, the device comprising a separable fixed electrical contact (4) and a movable electrical contact (6) and a mechanism (10) capable of switching the contacts between a closed state and an open state, the mechanism comprising: a switching shaft (20) coupled to the movable electrical contact (6); a trip hook (40) pivotably mounted on a fixed support of the mechanism; a connection system (22) coupling the switching shaft to the trip hook; Characterized in that the connection system (22) comprises a first link (50, 52) pair and a second link (60, 62) pair, the first link being pivotally mounted on the trip hook (40), the second link being mounted to pivot with the crank (24) of the switching shaft (20), and the first link being connected to the second link via a single articulation axis (68), the articulation axis (68) forming a pivot connection between the first link and the second link, and the articulation axis (68) combining the functions of ensuring the pivot connection and maintaining the spacing of the paired rods (42, 44), Each first link (50, 52) is mounted on a first region of the hinge axis (68) having a first diameter, and Each second link (60, 62) is mounted on a second region of the hinge axis (68) having a second diameter different from the first diameter.

2. The switching device according to claim 1, characterized in that: Each end of the hinge axis (68) includes a head (70, 72), each head including a widened portion forming a retaining portion for preventing the first link (50, 52) and the second link (60, 62) from being separated from each other.

3. The switching device according to claim 2, characterized in that: The hinge axis (68) includes a peripheral groove (74) formed at the bottom of each head (70, 72).

4. The switching device according to claim 3, characterized in that: The peripheral groove (74) has a depth between 0.2 mm and 0.6 mm.

5. The switching device according to claim 4, characterized in that: The depth of the peripheral groove (74) is equal to 0.4 mm.

6. The switching device according to any one of claims 2 to 4, characterized in that: The height of each head (70, 72) is less than or equal to 5 mm.

7. The switching device according to claim 6, characterized in that: The height of each head (70, 72) is between 2 mm and 3 mm.

8. The switching device according to any one of claims 2 to 5, characterized in that: The maximum width of the head (70, 72) is between 9 mm and 10 mm.

9. The switching device according to claim 8, characterized in that: The maximum width of the head (70, 72) is between 9.6 mm and 9.8 mm.

10. The switching device according to any one of claims 2 to 5, characterized in that: The articulation axis (68) is mounted in the connection system so as to have a radial play less than or equal to 0.1 mm for the first and second connecting rods.

11. The switching device according to any one of claims 2 to 5, characterized in that: The articulation axis (68) is made of a steel alloy.

12. The switching device according to claim 11, characterized in that: The articulation axis (68) is made of a steel alloy containing chromium and molybdenum.

13. The switching device according to any one of claims 2 to 5, characterized in that: The articulation axis (68) is formed from a one-piece component.

14. The switching device according to any one of claims 2 to 5, characterized in that: Each second link (60, 62) has an arc-shaped shape.

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