Current switching unit

Abstract

A switching unit (2) for switching an electric current, comprising separable fixed electrical contacts (4) and movable electrical contacts (8) and a mechanism (10) capable of switching the contacts between a closed state and an open state. The mechanism comprises: a switching shaft (20) coupled to the movable electrical contact (8); a release hook (40) mounted pivotably on a fixed support of the mechanism and including a hole in which a bearing (48) is received; and a linkage system (22) coupling the switching shaft (20) to the release hook. The linkage system includes articulated linkages that are rotatably linked relative to the release hook (40) and include a main bearing surface (85) that bears on the bearing (48) when the switching mechanism is in the closed state. The bearing (48) is configured to elastically deform when the switching mechanism transitions from the open state to the closed state and the linkage exerts a force on the bearing, to dampen the impact of the linkage on the bearing.

Description

Technical Field

[0001] The present invention relates to a switching unit for switching an electric current.

[0002] The present invention particularly relates to the field of electrical switching units for interrupting an electric current, such as circuit breakers or switches. Background Art

[0003] A switching unit having separable contacts includes a switching mechanism using an energy accumulator, the function of which is to move the electrical contacts of the unit between an open state and a closed state, for example in response to an actuation of a tripping device or a user.

[0004] An example of such a mechanism is described in FR-2 985 600-B1.

[0005] For example, a pivoting movable electrical contact is moved by a switching shaft that is mechanically coupled to a tripping hook by means of a linkage system. To close the contacts, a mechanical energy accumulator including one or more springs is actuated to move the linkage system.

[0006] Thus, whenever the contacts are opened and closed, the switching mechanism is subjected to many mechanical stresses, such as internal shocks.

[0007] For a long time, such a mechanism has been satisfactory. However, in some contemporary applications, the increase in the electrical power associated with the switching unit and the regulatory requirements require an increase in the capacity of the mechanical energy accumulator in order to increase the speed of contact closing, which places greater stress on the switching mechanism and reduces the number of acceptable opening and closing cycles during the product's service life.

[0008] To reduce the stress on the switching mechanism, it is known to slow down or damp the switching shaft by using a device external to the switching mechanism. However, this solution creates additional volume and has limited effectiveness in increasing the life of the switching mechanism.

[0009] It is also known to strengthen the corresponding mechanical components, particularly by increasing the thickness of the mechanical components, but this solution exacerbates the inertia effect, which limits the actual benefits obtained in terms of life.

[0010] There is a desire for a switching mechanism with improved durability, for example in order to increase the number of acceptable opening and closing cycles during the life of the product. Summary of the Invention

[0011] Therefore, there is a need for a switching unit for switching an electric current, in which the switching mechanism has improved reliability without resorting to adding components external to the mechanism.

[0012] With this in mind, the present invention relates to a switching unit for switching current, which includes separable fixed electrical contacts and movable electrical contacts, and a mechanism capable of switching the contacts between a closed state and an open state. The mechanism includes:

[0013] - A switching shaft coupled to the movable electrical contact;

[0014] - A release hook, mounted pivotably on a fixed support of the mechanism, and including a hole for receiving an abutment;

[0015] - A linkage system that couples the switching shaft to the release hook. The linkage system includes articulated linkages that are rotatably linked relative to the release hook and include a main support surface that bears on the abutment when the switching mechanism is in the closed state. According to the invention, the abutment is configured to elastically deform when the switching mechanism transitions from the open state to the closed state and the linkage exerts a force on the abutment, so as to damp the impact of the linkage on the abutment.

[0016] With the present invention, the abutment is elastically deformable and allows the kinetic energy of the linkage to be absorbed, thereby extending the life of the mechanism. This effect is achieved without adding components external to the mechanism, which is advantageous in terms of volume and cost.

[0017] Advantageously, an elastic damping element located at the abutment damps the linkage before the linkage bears on the abutment, which further improves the absorption of kinetic energy each time the mechanism transitions from the open state to the closed state.

[0018] According to some advantageous but non-mandatory aspects of the present invention, such a support can incorporate one or more of the following features adopted in any technically acceptable combination:

[0019] - The abutment is made of highly elastic steel;

[0020] - The abutment includes a helical pin;

[0021] - The abutment is held in the hole of the release hook by elastic reset of the abutment;

[0022] - The switching unit includes an elastically deformable damping element that is in a relaxed configuration when the switching mechanism is in the open state, and when the switching mechanism is in the closed state, a secondary support surface of the linkage bears on a corresponding support portion of the damping element, and the damping element is in a deformed configuration;

[0023] - The damping elements are each located at a corresponding end of the abutment and each include an orifice to hold them on the abutment, and each damping element further includes a through slot, so that in the closed state of the switching unit, the main support surface of the linkage directly bears on the abutment;

[0024] - Each damping element includes a front part and a rear part, which are located on both sides of the through slot and are configured such that when the tripping mechanism changes from the open state to the closed state, before the main support surface of the connecting rod directly supports on the support, it contacts the secondary support surface of the connecting rod;

[0025] - The damping element includes a deformable cavity formed in the front part, which is open when the damping element is in the relaxed configuration and closed when the switching unit is in the closed state;

[0026] - The damping element is configured such that each cavity in the front part has a corresponding thickness measured parallel to the average support direction, and the sum of the thicknesses is 30% to 70%, preferably 40% to 60% of the dimension of the front part measured parallel to the average support direction, which is defined by the direction of the contact force between the connecting rod and the front part when the switching unit changes from the open state to the closed state;

[0027] - The damping element is made of an elastomeric material with a Shore A hardness of 50° to 90°, preferably 60° to 80°, and more preferably substantially equal to 70°;

[0028] - The switching mechanism includes two spacer bars, which are integral with the tripping hook and each is located at a corresponding damping element. Each spacer bar has a support surface configured to interact with the lower surface of the damping element in a form - fit manner. The lower surface is positioned opposite to the front part and the rear part in the average support direction of the connecting rod. Therefore, in the deformed configuration, the damping element will be deformed by compression, and

[0029] - The front part of the damping element partially protrudes beyond the support surface such that when the switching unit is in the closed state, the front part of each damping element further includes a region deformed by tension. Description of the Drawings

[0030] The present invention will be better understood from the following description of an embodiment of a switching unit for switching an electric current according to its principle, and its other advantages will become more apparent. The description is provided only by way of example and with reference to the drawings, in which:

[0031] Figure 1 A switching unit with separable contacts is schematically shown, which is shown in cross - section in the intermediate plane and includes a switching mechanism with a connecting rod according to the present invention. The mechanism and the connecting rod are shown in a simplified manner in a first configuration;

[0032] Figure 2 is Figure 1 a partially exploded perspective view of the connecting rod in [the figure], which is in a second configuration;

[0033] Figure 3 as viewed in the direction of arrow III in Figure 2 a perspective view of certain parts of the link in the assembled configuration; and Figure 2 and

[0034] Figure 4 is Figure 2 a cross-sectional view of the link in a cross-sectional plane parallel to the intermediate plane, showing the assembly in a third configuration. DETAILED DESCRIPTION

[0035] Figure 1 shows a part of an electrical switching unit 2 for interrupting an electric current, such as a circuit breaker or a contactor. The switching of the current takes place in air and via separable electrical contacts.

[0036] According to some examples, the unit 2 is a low-voltage high-current multi-pole circuit breaker.

[0037] The unit 2 includes a fixed electrical contact 4 and a movable pole 6 which, in some examples, carries contact fingers 8 that are mounted to pivot and are arranged opposite the fixed contact 4. The contacts 4 and 8 are connected to opposite electrical connection terminals of the unit 2.

[0038] The movable pole 6 is reversibly movable, for example, by pivoting relative to a fixed frame of the unit 2 between an open position and a closed position of the contacts (corresponding respectively to an electrical open state and an electrical closed state of the unit 2). The axis of rotation of the movable pole 6 is denoted herein by the reference numeral X6.

[0039] The unit 2 also includes a switching mechanism 10 which is adapted to switch the contacts 4 and 8 between an open state and a closed state by moving the movable pole 6 between the open position and the closed position.

[0040] The contact fingers 8 carried by the movable pole 6 are movable electrical contacts which are rotatably movable, in particular, about the axis of rotation X6 relative to the frame of the unit 2 during the switching movement of the unit 2 between the electrical open and closed states.

[0041] For the sake of convenience and for purposes of illustration, an intermediate plane P1 is defined as a plane orthogonal to the axis X6. The intermediate plane P1 is also the Figure 1 plane of the image in

[0042] In the illustrated embodiment, the pivoting and rotational movements of the elements of the mechanism 10 occur about axes of rotation which are fixed relative to the frame and extend parallel to each other, in this case, extending in a direction perpendicular to the plane P1.

[0043] According to some embodiments, unit 2 is a multi-pole unit adapted to interrupt polyphase current. Thus, unit 2 includes a plurality of poles, each pole being associated with one electrical phase and including a pair of contacts 4 and 8. According to some non-limiting examples, unit 2 includes three, four, six or eight poles.

[0044] According to some embodiments, mechanism 10 is a switching mechanism using a mechanical accumulator. For example, the operating principle of a switching mechanism based on this technology is described in FR 2 985600B1.

[0045] Mechanism 10 particularly includes a switching shaft 20 which, in this case, is coupled to the movable pole 6 via a crank 24 and a connecting rod 25. The shaft 20 is rotatable about its longitudinal axis relative to the fixed frame or fixed support of the switching unit 2. In other words, the switching shaft 20 is coupled to the contact finger 8 which is a movable contact.

[0046] When unit 2 includes a plurality of poles, the shaft 20 is common to all the poles and is mechanically coupled to each movable pole 6.

[0047] Mechanism 10 further includes a release hook 40 and a linkage system 22 that couples the switching shaft to the release hook.

[0048] For example, as described below, the linkage system 22 is articulated by a pivot link to one arm of the crank 24 carried by the shaft 20.

[0049] Mechanism 10 further includes an opening pawl 26 associated with a bolt 28, also known as a "half moon".

[0050] The opening pawl 26 is mounted to pivot relative to the frame and interacts with the release hook 40. A spring 29 engages between the shaft 20 and an axis integral with the frame of unit 2.

[0051] The closing bolt 30 (also known as a "half moon") and an intermediate rod 31 mechanically interact with an actuator (such as an electromagnetic actuator having a coil) controlled by the release device 12 and / or with a manual control device. Figure 1 The association between the release device and the rod 31 is schematically shown by a rod, although in practice this mechanical interaction can be produced in a completely different way.

[0052] The bolt 30 is also mechanically associated with a closing pawl 32 which is mounted to pivot relative to the frame.

[0053] Furthermore, mechanism 10 includes a mechanical energy storage device 34 which includes at least one spring. For example, device 34 stores mechanical energy when the spring is compressed and releases this mechanical energy when the spring relaxes.

[0054] In this case, a drive mechanism 36 including one or more link members hinged and / or mounted pivotably relative to a fixed frame is mechanically coupled to the device 34. The drive mechanism 36 acts on the linkage system 22 so as to strike the linkage system and drive it to a closed position. In this way, upon movement, the linkage system 22 in turn drives the release hook 40.

[0055] In the example shown, the release hook 40 also has an aperture 46 for receiving a pivot link of the frame and is hinged to the linkage system 22 by the pivot link.

[0056] Figure 2 The linkage system 22 and the hook 40 are also shown in more detail.

[0057] The linkage system 22 includes a first pair of connecting rods 42 and a second pair of connecting rods 44 that are hinged to each other, and pivot links for hinging to the release hook 40 and the shaft 20 are formed thereon. The two pairs of connecting rods 42 and 44 together form a hinged "linkage" 45.

[0058] In the example shown, the release hook 40 also has an aperture 46 and a support 48. The aperture 46 is for receiving a pivot link of the frame, and the support 48 is received in a hole of the hook 40 and projects on both sides of the hook 40 in this case. For example, the release hook 40 has a substantially flat shape parallel to the intermediate plane P1.

[0059] According to some embodiments, as will be understood by reading the examples provided below, the support 48 is more generally configured to elastically deform when the switching mechanism 10 transitions from an open state to a closed state and the linkage 45 exerts a force on the support, so as to damp the impact of the linkage 45 on the support 48.

[0060] The first pair of connecting rods 42 includes two similar or identical connecting rods 50 and 52 that are arranged parallel and opposite to each other. According to some examples, the connecting rods 50 and 52 have a flat shape.

[0061] A first end of each of the connecting rods 50 and 52, in this case the lower end, is mounted to pivot on the release hook 40, and more precisely, to pivot on the distal end 54 of the release hook 40.

[0062] In this case, the pivot link is formed by a rigid shaft 56 (such as a trunnion) that extends perpendicular to the connecting rods 50 and 52. The reference numeral X56 denotes the axis of rotation associated with this pivot link. In this case, the axis X56 is parallel to the axis X6.

[0063] According to some examples, the connecting rod system 22 further includes a bushing 58 which is mounted between the connecting rods 50 and 52 on a spacer 59, and the spacer 59 fixes the connecting rods 50 and 52 to each other. In this case, the spacer 59 extends parallel to the axis X56.

[0064] For example, when the device 34 releases energy, the spacer 59 and the bushing 58 are struck by the drive mechanism 36.

[0065] The second pair of connecting rods 44 includes two similar or identical connecting rods 60 and 62 which are arranged parallel and opposite to each other. According to some examples, the connecting rods 60 and 62 have a flat shape.

[0066] According to some alternative but still advantageous embodiments, each of the second connecting rods 60 and 62 has a shape curved into an arc, thereby reducing the volume, improving the distribution of mechanical stress and increasing the mechanical toughness of the system 22.

[0067] The first ends of the connecting rods 60 and 62, in this case the upper ends, are adapted to be mounted to pivot on the shaft 20, more precisely on an arm of the crank 24, and in this case, to pivot in an orifice formed in this arm of the crank 24.

[0068] This pivot link is formed by a rigid shaft 64 which extends perpendicular to the connecting rods 60 and 62 and preferably projects relative to the outer lateral faces of the connecting rods 60 and 62. The reference numeral X64 denotes the axis of rotation associated with this pivot link. In this case, the axis X64 is parallel to the axis X56. The rigid shaft 64 is placed on the said first ends of the connecting rods 60 and 62.

[0069] According to some examples, the rigid shaft 64 is mounted to be translationally linked to the connecting rods 60 and 62. In other words, the rigid shaft 64 can rotate but remains translationally fixed relative to the connecting rods 60 and 62.

[0070] The connecting rods 60 and 62 forming the second pair of connecting rods 44 are kept at a certain distance from each other in the direction X64 to allow the end 66 of the release hook 40 to pass between the connecting rods 60 and 62.

[0071] This end 66 has a V-shaped fastening part 67 which interacts with the opening pawl 26, for example by bearing on a support linked to the axis 27 of the opening pawl 26 in the closed position.

[0072] The connecting rods 50 and 52 are connected to the connecting rods 60 and 62 by a single hinge axis 68, which forms a pivot link between the connecting rods 50 and 52 of the first pair 42 and the connecting rods 60 and 62 of the second pair 44. The reference numeral X68 denotes a straight line providing the axis of rotation associated with this pivot link.

[0073] The hinge axis 68 extends along this axis X68, which is hereinafter referred to as "direction X68" to avoid any confusion with the hinge axis 68.

[0074] According to some examples, the connecting rods 60 and 62 are arranged on either side of the connecting rods 50 and 52 and are in contact with the connecting rods 50 and 52 over a part of their length. The connecting rod 50 is adjacent to the connecting rod 60, and the connecting rod 52 is adjacent to the connecting rod 62.

[0075] The pivot link formed by the hinge axis 68 is formed on the other end of each of the connecting rods 50, 52, 60 and 62, that is to say on the second ends of the connecting rods 50 and 52 and on the second ends of the connecting rods 60 and 62. In fact, the second end of each connecting rod is positioned opposite the first end of said connecting rod.

[0076] Thus, in the example shown, the pivot link formed by the hinge axis 68 is located at the lower ends of the connecting rods 60 and 62 and at the upper ends of the connecting rods 50 and 52. Thus, in these examples, the hinge is substantially formed in the middle of the linkage system 22.

[0077] Some operating examples of the mechanism 10 will now be briefly described.

[0078] In Figure 1 the stable open position shown, the storage device 34 is armed, that is to say, the spring is compressed and stores energy. The bolt 30 holds the closing pawl 32 in the first position.

[0079] To close the contacts 4 and 8, the closing bolt 30 is moved, for example, by the action of a tripping device 12 or a button, which releases the closing pawl 32.

[0080] The movement of the closing pawl 32 actuates the device 34, and the energy stored in the device 34 is released by the relaxation movement of the spring, and this actuates the linkage system 22, for example by striking the bushing 58, by means of the drive mechanism 36 so as to move the movable pole 6 through the shaft 20 until the contact finger 8 contacts the fixed contact 4.

[0081] The linkage system 22 continues to move towards its closed position until it reaches in front of a predetermined alignment position called "neutral", driving the tripping hook 40 and the opening pawl 26 towards the abutment position, in which the linkage system 22 is prevented from returning backwards.

[0082] Then, the connecting rod 45, more precisely the first pair of connecting rods 42, comes into contact with the support 48 to lock the position of the linkage system 22.

[0083] Then, the mechanism 10 is in a stable closed position.

[0084] To reopen the unit 2, for example, by moving the rod 31 by means of the actuator 12 or by a manual action directly on the bolt 28, the lock between the opening pawl 26 and the bolt 28 is broken. The opening pawl 26 pivots, releasing the abutment of the release hook 40.

[0085] Then, the linkage system 22 is no longer held in abutment by the hook 40, and the support 48, under the action of the return force exerted by the spring 29, forces the first pair of connecting rods 42 to move away, thus causing the linkage system 22 to return towards the open position. Once the linkage system 22 has returned behind the neutral position, the movable pole 6 is driven towards its open position. The mechanism 10 has returned to the stable open position.

[0086] As shown in such cases in Figure 2 、 3 and 4, the support 48, which is visible in a relatively large proportion, includes a helical pin. The helical pin, described for example in the standards ISO 8748 and ISO 8750, is formed by the coiling of a metal sheet, for example made of highly elastic steel.

[0087] "Highly elastic steel" should be understood to mean a steel grade designed for shock and bending resistance. There are many steel grades, and a person skilled in the art will be able to select the most suitable steel grade based on the geometry of the support 48 and the expected performance levels, particularly in terms of durability and kinetic energy absorption. As a non - limiting example, quenched steel 420 - 545HV or stainless steel "1.4310" grade can give good results.

[0088] The support 48 has a generally cylindrical shape with a circular cross - section, whose generatrix extends along the axis X48, which is parallel to the axis X56, and the support 48 has an outer surface 70, which has two opposite ends 72 and 74, which are frustoconical in this case.

[0089] The support 48 is closely introduced into the hole of the hook 40, in which the support 48 is received, and the support 48 is held in said hole by elastic reset. In particular, the support 48 is not welded to the hook 40, but remains free to elastically deform under the action of an external force; in particular, when the mechanism 10 is closed and when the connecting rod pair 42 bears on the support 48, the support 48 remains free to deform by flexure.

[0090] This helical pin used as the support 48 is particularly resistant to impact and material fatigue, especially compared to the solid cylindrical supports in the prior art, which are usually made of hard but inflexible steel, or compared to split pins. Of course, the support 48 can have a shape other than a helical pin, as long as an equivalent level of impact resistance is achieved.

[0091] Furthermore, the switching unit 2 includes two damping elements 76 and 78.

[0092] Each damping element 76 or 78 is located at the corresponding end 72 or 74 of the support 48, and the damping elements 76 and 78 are symmetrically arranged on both sides of the hook 40. Advantageously, the damping elements 76 and 78 have a symmetric structure with respect to the intermediate plane P1.

[0093] The damping elements 76 and 78 are configured to damp the movement of the connecting rod 45 by elastic deformation when the unit 2 changes from the open state to the closed state.

[0094] The damping elements 76 and 78 are in a configuration called "relaxed" when the switching mechanism 10 is in the open state, and in a configuration called "deformed" when the switching mechanism 10 is in the closed state, and a part of the connecting rod 45 is supported on the damping elements 76 and 78.

[0095] In Figure 3 only the damping element 78 is visible, while in Figure 4 only the connecting rod 52 and the damping element 78 are visible. Assuming that the connecting rod 50 and the damping element 76 have a symmetric structure and work in the same way, only the connecting rod 52 and the damping element 78 will be described below.

[0096] In Figure 3 the visible damping element 78 includes a central portion 79 in the form of a ring or a cylinder, in which an orifice 80 is formed, and the orifice 80 interacts with the support 48 to hold the damping element 78 on the support 48. The damping element 78 has a front portion 82 and a rear portion 84 that are integral with the central portion 79 and extend on both sides of the central portion 79, and the rear portion 84 is closer to the distal end 54 of the hook 40 than the front portion 82.

[0097] A through slot 90 is formed in the central portion 79 between the front portion 82 and the rear portion 84 in the radial direction with respect to the axis X48. The through slot 90 allows the connecting rod 52 to pass through, so that when the switching unit 2 is in the closed state, the connecting rod 52 is directly supported on the support 48. More precisely, the main support surface 85 of the connecting rod 52 is directly supported on the outer surface 70 of the support 48.

[0098] The through slot 90 allows the damping element 78, which is made of an elastomeric material in this case, to be prevented from shearing between the connecting rod 52 and the support 48, and shearing would cause rapid deterioration of the damping element 78.

[0099] In Figure 4 it is shown that during the closing movement of the mechanism 10, the unit 2 is in an intermediate configuration between the open state and the closed state. In particular, the connecting system 22 is not yet supported on the support 48. In Figure 4 the intermediate configuration, the connecting rod 45 just contacts the damping element 78 which is still in a relaxed configuration. More precisely, the front part 82 and the rear part 84 respectively contact the secondary support surfaces 86 and 88 of the connecting rod 52, and the secondary support surfaces 86 and 88 are located on both sides of the main support surface 85.

[0100] For the purpose of illustration, the average support direction F86 of the secondary support surface 86 on the front part 82 is defined as the movement direction of the secondary support surface 86 when it contacts the front part 82, that is, in Figure 4 the configuration shown. The average support direction F86 is shown by an arrow in Figure 4 and the arrow F86 is orthogonal to the axis X56 about which the connecting rod 52 pivots.

[0101] In particular, the secondary support surface 86 is arranged at the end of the protrusion 92 of the connecting rod 52, and the protrusion 92 extends to protrude from the end of the connecting rod 52 including the axis X68 towards the front part 82 of the damping element 78 in a direction substantially orthogonal to the rotation axis X56 of the connecting rod 52. The protrusion 92 allows the contact between the support surface 86 and the front part 82 to occur together with the contact between the support surface 88 and the rear part 84, thereby stabilizing the damping element 78 around the support 48.

[0102] In Figure 4 the intermediate configuration shown, it should be understood that the front part 82 and the rear part 84 of the damping element 78 contact the secondary support surfaces 86 and 88 of the connecting rod 45 before the main support surface 85 of the connecting rod 45 directly supports on the support 48, which allows the damping elements 76 and 78 to absorb some kinetic energy of the connecting rod 45 before the impact on the support 48 through elastic deformation.

[0103] The energy dissipated by damping is generally equal to the work of the contact force between the damping element 78 and the connecting rod 52, that is, equal to the intensity of the contact force between the damping element 78 and the connecting rod 52 multiplied by the movement amplitude of the contact point.

[0104] It can be understood that if the contact between the damping element 78 and the connecting rod 45 occurs as early as possible before the connecting rod 45 directly contacts the support 48, the damping effect is greater. Similarly, for the same elastic deformation, a hard or rigid elastomer generates a greater force than a soft elastomer, and the damping effect is greater.

[0105] However, if the internal force within the elastomeric material exceeds a certain limit, the material may deteriorate due to fragmentation. It can be understood that the harder the elastomeric material, the lower its ability to elastically deform.

[0106] Therefore, deformable cavities 101, 102, and 103 are formed in the front portion 82 of the damping element 78 such that the damping element 78 can deform over a relatively large spatial amplitude while being made of a relatively hard elastomeric material.

[0107] The hardness of the elastomer can be evaluated by a standardized test called the "Shore hardness test", and the results are expressed on a scale called "Shore A" that ranges from 0° to 100°. "Relatively hard" should be understood to mean that the damping element 78 is made of an elastomeric material having a hardness on the Shore A scale of 50° to 95°. Preferably, the hardness of the elastomer is 60° to 80°, and more preferably substantially equal to 70°.

[0108] In the example shown, the cavities 101 to 103 each have an elongated elliptical shape, and the length of each ellipse is arranged perpendicular to the average support direction F86 of the connecting rod 52.

[0109] Similarly, a cavity 104 having a circular cross-section in this case is formed in the rear portion 84 of the damping elements 76 and 78.

[0110] When the damping element 78 is in the relaxed configuration, the cavities 101 to 104 are open, that is, the inner surfaces of each of the cavities 101 to 104 that are positioned opposite each other in the average support direction F86 do not contact, while when the switching unit 2 is in the closed state, the cavities 101 to 104 are closed, that is, the inner surfaces of each of the cavities 101 to 104 contact each other.

[0111] Therefore, compared to the damping elements 76 or 78 without cavities, the combination of the relatively hard elastomeric material and the cavities 101 to 104 formed in the damping elements 76 and 78 allows for a higher damping force to be generated and over a longer spatial amplitude. In Figure 4 wherein, the dimension D1 is defined as the dimension of the cavity 101 measured parallel to the average support direction F86 when the damping element 78 is in the relaxed configuration. Similarly, the dimension D2 associated with the cavity 102 and the dimension D3 associated with the cavity 103 are defined.

[0112] The dimension D82 of the front part 82 is also defined as the dimension of the front part 82 measured parallel to the main support direction F86 when the damping element 78 is in the relaxed configuration. The cavities 101 to 103 of the front part 82 represent the total thickness equal to the sum of the dimensions D1, D2 and D3, which is 30% to 70% of the dimension D82 of the front part 82. Preferably, the total thickness of the cavities 101, 102 and 103 is between 40% and 60% of the dimension D82 of the front part 82 of the damping element 78.

[0113] Of course, the number and shape of the cavities 101 to 104 are non - restrictive, and cavities with different shapes from the cavities 101 to 104 can be manufactured in the damping element 78, as long as a similar effect in terms of damping and durability is obtained.

[0114] Furthermore, the switching unit 2 includes two spacer bars 106 and 108, which are symmetrically located on both sides of the hook 40 with respect to the intermediate plane P1. Advantageously, the spacer bars 106 and 108 have a symmetrical structure with respect to the intermediate plane P1.

[0115] Each of the spacer bars 106 and 108 is located at the corresponding damping element 76 or 78 and has a housing 109 and a support surface 110.

[0116] Firstly, the spacer bars 106 and 108 interact with the axis passing through the orifice 46, and secondly, the housing 109 interacts with one of the ends 72 or 74 of the support 48, thereby fixing the spacer bars 106 and 108 to the hook 40.

[0117] In the example shown, the cross - section of the support surface 110 on the intermediate plane P1 has an L - shape, which interacts in a form - fitting manner with the lower surfaces 112 of the damping elements 76 and 78. The lower surfaces 112 of each of the damping elements 76 and 78 are positioned opposite to the front part 82 and the rear part 84 in the support direction F86 of the connecting rod 45, so that in the deformed configuration of the damping elements 76 and 78, the damping elements 76 and 78 are mainly deformed by compression. The support surface 110 also prevents the rotational movement of the damping elements 76 and 78 about the axis X48 of the support 48.

[0118] For each of the damping elements 76 and 78, the lower surface 112 is aligned with a first part of the front part 82 in the average support direction F86, and this first part is located near the through - slot 90. A second part of the front part 82 away from the through - slot 90 is not aligned with the lower surface 112 in the average support direction F86. In other words, the front part 82 partially protrudes beyond the support surface 110. When the switching unit 2 is in the closed state, the front part 82 of each damping element 76 or 78 thus includes a region deformed by tension, which further contributes to damping the connecting rod 45 over a larger spatial amplitude when the switching unit 2 changes from the open state to the closed state.

[0119] Of course, the support surface 110 may have a shape other than the L-shaped shown in the figure, as long as the support surface 110 allows the damping elements 76 and 78 to be supported while allowing the damping elements 76 and 78 to deform over a relatively large spatial range.

[0120] The above-described embodiments and variations can be combined to produce new embodiments of the present invention.

Claims

1. A switching unit (2) for switching an electric current, the unit comprising separable fixed electrical contacts (4) and movable electrical contacts (8) and a switching 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 (8); A release hook (40), mounted to pivot on a fixed support of the mechanism and including a hole for receiving a support seat (48), A linkage system (22) coupling the switching shaft (20) to the release hook, the linkage system including articulated linkages (45), the linkages being rotatably linked relative to the release hook (40) and including a main support surface (85), the main support surface bearing on the support seat (48) when the switching mechanism is in the closed state, Characterized in that the support seat (48) is configured to elastically deform when the switching mechanism changes from the open state to the closed state and the linkage exerts a force on the support seat, to damp the impact of the linkage on the support seat.

2. The switching unit (2) according to claim 1, characterized in that The support seat (48) is made of highly elastic steel.

3. The switching unit (2) according to claim 2, characterized in that The support seat (48) includes a helical pin.

4. The switching unit (2) according to any one of the preceding claims, characterized in that The support seat (48) is held in the hole of the release hook (40) by elastic reset of the support seat.

5. The switching unit (2) according to any one of claims 1 to 3, characterized in that The switching unit includes elastically deformable damping elements (76, 78), which are in a relaxed configuration when the switching mechanism (10) is in the open state, and when the switching mechanism is in the closed state, secondary support surfaces (86, 88) of the linkage (45) bear on corresponding support portions (82, 84) of the damping elements, and the damping elements are in a deformed configuration.

6. The switching unit (2) for switching an electric current according to claim 5, characterized in that Each of the damping elements (76, 78) is located at a respective end (72, 74) of the support seat (48), and each includes an orifice (80) to hold them on the support seat, and each damping element further includes a through slot (90), so that in the closed state of the switching unit, the main support surface (85) of the linkage bears directly on the support seat.

7. The switching unit (2) according to claim 6, characterized in that Each damping element includes a front portion (82) and a rear portion (84), the front portion and the rear portion being located on both sides of the through slot (90), and being configured such that when the switching mechanism (10) changes from the open state to the closed state, before the main support surface (85) of the linkage bears directly on the support seat (48), it contacts the secondary support surfaces (86, 88) of the linkage (45).

8. The switching unit (2) according to claim 7, characterized in that The damping elements (76, 78) include deformable cavities (101, 102, 103) formed in the front part (82), which are open when the damping elements (76, 78) are in the relaxed configuration and closed when the switching unit (2) is in the closed state.

9. The switching unit (2) according to claim 8, characterized in that the damping elements (76, 78) are configured such that each of the cavities (101, 102, 103) in the front part (82) has a respective thickness (D1, D2, D3) measured parallel to the average support direction (F86), and the sum of the thicknesses is 30% to 70% of the dimension (D82) of the front part (82) measured parallel to the average support direction, the average support direction (F86) being defined by the direction of the contact force between the link (45) and the front part (82) when the switching unit changes from the open state to the closed state.

10. The switching unit (2) according to claim 9, characterized in that, The sum of the thicknesses is 40% to 60% of the dimension (D82) of the front part (82) measured parallel to the average support direction.

11. The switching unit (2) according to claim 5, characterized in that the damping elements (76, 78) are made of an elastomeric material having a Shore A hardness of 50° to 90°.

12. The switching unit (2) according to claim 11, characterized in that, The damping elements (76, 78) are made of an elastomeric material having a Shore A hardness of 60° to 80°.

13. The switching unit (2) according to claim 12, characterized in that, The damping elements (76, 78) are made of an elastomeric material having a Shore A hardness equal to 70°.

14. The switching unit (2) according to claim 9, characterized in that the switching mechanism (10) includes two spacer bars (106, 108), which are integral with the release hook (40) and each located at a respective damping element (76, 78), and each spacer bar has a support surface (110) configured to interact in a form-fitting manner with the lower surface of the damping element, the lower surface being positioned opposite the front and rear parts (82, 84) in the average support direction (F86) of the link (45) such that in the deformed configuration, the damping element is deformed by compression.

15. The switching unit (2) according to claim 14, characterized in that the front part (82) of the damping elements (76, 78) projects partially beyond the support surface (110) such that when the switching unit is in the closed state, the front part (82) of each damping element also includes a region deformed by tension.

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