Terminals and electrical protective devices that connect electrical conductors to connection pads of electrical equipment
By using nuts and intermediate plates with elastic branches in the connection terminals, the fastening and safe disengagement of the correct torque is achieved automatically, and the torque tightening problem of cable and circuit breaker connection is solved, improving safety and convenience.
Patent Information
- Application Number
- CN201910743285.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2018-09-13
- Filing Date
- 2019-08-13
- Publication Date
- 2024-12-31
- Estimated Expiration
- 2039-08-13
AI Technical Summary
During the connection between the cable and the circuit breaker, it is difficult for the installer to ensure the correct torque of the connection point is tightened, resulting in safety risks, and existing torque wrenches are expensive and require frequent calibration.
A connection terminal is designed, using nuts and intermediate plates with elastic branches. By screwing the screws, the reverse torque is generated, and the correct clamping torque is automatically achieved and the clicking sound is made to ensure tightness. The nut reaches the clamping torque. Retie and prevent the screw from rotating when twisting.
It achieves simple and economical guarantees the correct torque tightening of the conductor without the need for a dedicated torque wrench, reducing operational complexity and equipment costs, and improving safety and convenience of use.
Smart Images
Figure CN110896015B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a terminal for connecting an electrical conductor to a connection pad belonging to an electrical device, comprising a holder capable of being fixed inside a housing of the device and comprising a hole of substantially parallelepiped shape and delimited by four walls, this hole capable of receiving said pad, one of said walls of said holder comprising a hole capable of allowing the passage of a screw, said screw comprising means for actuating said screw at one of its ends situated outside the holder, and comprising a clamping shoe at its opposite end capable of allowing the conductor to be clamped between said pad and said shoe when the screw is actuated to drive a relative translation movement between the screw and the holder.
[0002] The invention also relates to an electrical protection device comprising such a terminal. Background Art
[0003] So-called screw terminals of the aforementioned kind are described, for example, in patent EP0555157.
[0004] For reasons of safety for people and goods, the electrical connection of the cables to the connection pads of the circuit breaker often presents problems.
[0005] In fact, installers working in the field do not have torque wrenches that can tighten the various connection points to the correct torque. These torque wrenches are expensive and must be calibrated about once a year.
[0006] Furthermore, these wrenches sometimes do not have the correct selection of torque corresponding to a particular range.
[0007] As a result, the fixtures are sometimes tightened intuitively by an increasingly unskilled workforce. The result is that re-tightening campaigns must be carried out to ensure compliance with the manufacturer's recommended clamping torque.
[0008] The present invention solves this problem and proposes a connection terminal and an electrical protection device comprising such a terminal, which can simply and economically tighten the correct torque of the conductor in the terminal. Summary of the invention
[0009] To this end, the invention comprises a connection terminal of the type described above, characterized in that it comprises an intermediate stage formed inside the retaining frame C to allow the reception of a nut having a resilient branch, the nut having a threaded hole through which the clamping screw is screwed, the resilient branch interacting with a form provided on the side wall of the retaining frame C so that, once the correct clamping torque is reached, the nut is disengaged from the screw in rotation and engages from the beginning to the end of unscrewing.
[0010] According to a particular feature, the two elastic branches can be radially compressed when screwed onto the track belonging to the cage C, the compression of the branches generating a torque opposing that of tightening the screw until the branches disengage from the ramp once the desired clamping torque is reached.
[0011] According to a particular feature, this terminal comprises means for producing a clicking sound once the above-mentioned branch has disengaged from the ramp.
[0012] According to another feature, the above-mentioned nut comprises an annular portion comprising the hole through which the above-mentioned screw passes and from which two elastic branches branch off, extending circumferentially around this annular portion in respective opposite directions.
[0013] According to another feature, each branch comprises at its free end an attachment element capable of cooperating with a first and a second recessed form provided on each side wall of the cage C, each element forming a hook which cooperates with the so-called first recessed form during clamping and with the second recessed form during unscrewing.
[0014] According to another feature, the above-mentioned so-called first and second recessed forms are produced by stamping the inside of the side wall of the cage.
[0015] According to another feature, in each side wall, two recessed forms extend in a direction substantially perpendicular to the axis X of the cage C, the two recessed forms of one side wall being arranged opposite the two recessed forms of the other side wall.
[0016] According to another feature, each so-called first recessed form comprises a surface portion forming an attachment ramp for a so-called second recessed form facing the same wall, the passage through this attachment ramp for the attachment element to reconnect the second recessed form causing the above-mentioned disengagement from the screw.
[0017] According to another feature, each so-called second recessed form comprises a wall portion positioned facing the so-called first recessed form associated therewith, which wall portion extends substantially perpendicularly to the axis X of the cage C and forms an abutment that blocks the rotation of the nut during the unscrewing operation, thereby producing an engagement of the clamping screw from the beginning to the end of unscrewing.
[0018] According to another feature, the intermediate stage is formed by a plate mounted inside the cage C and pressed onto the inside of the cage C.
[0019] According to another feature, the plate comprises two so-called first lugs and two so-called second lugs, the two so-called first lugs being able to be introduced into corresponding holes belonging to two edges of the two side walls at the end of the insertion of the plate into the holder, and the two so-called second lugs being able to be introduced into two holes belonging to two edges of the side walls, which are opposite the front edge, by clamping the metal sheet of the plate.
[0020] The invention also comprises an electrical protection device comprising at least one upstream terminal and / or at least one downstream terminal having the above-mentioned features alone or in combination. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] However, other advantages and features of the present invention will become more apparent during the course of the following detailed description made with reference to the accompanying drawings which are provided by way of example only and in which:
[0022] Figure 1 is a perspective view of a friction ring belonging to a terminal according to a specific embodiment of the present invention;
[0023] Figure 2 is a perspective view of a nut belonging to the same terminal, viewed from above;
[0024] Figure 3 is a perspective view showing the assembly of the ring to the nut;
[0025] Figure 4 is a perspective view of the same nut viewed from below;
[0026] Figure 5 is a perspective view of a retainer belonging to a terminal according to the present invention;
[0027] Figure 6 is a perspective view of the same cage before the aforementioned nut is placed in the cage;
[0028] Figure 7 It is a perspective view of the middle panel alone;
[0029] Figure 8 is a perspective view of the aforementioned retainer of the terminal with the nut placed in the terminal and before the terminal plate is introduced;
[0030] Fig. 9 is a front view of a terminal according to the present invention when fastened;
[0031] Fig.10 is an axial cross-sectional view of a terminal in a released position according to the present invention, without a cable and a plate;
[0032] Fig.11 and Fig.12are perspective views of the same terminal viewed from the insertion side and the opposite side of the insertion side, respectively;
[0033] Fig.13 It is along Fig.10 A cross-sectional view taken along line AA of FIG. 1 , showing the position of the nut reaching the ramp and allowing screwing;
[0034] Fig.14 A top view of the nut alone, in its previous position, showing the friction between the cage and the nut as it relates to the tightening torque.
[0035] Fig.15 It is along Fig.10 The line AA intercepts Fig.13 The same cross-sectional view, but showing the terminal after twisting, in a position that allows untwisting, and
[0036] Fig.16 is a cross-sectional view taken along line AA showing four different positions of the nut. DETAILED DESCRIPTION
[0037] exist Fig.10 In the figure, a holder C belonging to a connecting terminal B according to the invention can be seen, which terminal is used to be installed and fixed inside an electrical protection device such as a low-voltage circuit breaker so as to be able to electrically connect a connecting pad 1 of the device with an electrical conductor 2 such as a cable.
[0038] In a manner known per se, this terminal B comprises a holder C of generally parallelepipedal shape, comprising a metal part 3 comprising four walls 4, 5, 6, 7, parallel in pairs, namely an upper wall 4, a lower wall 5 and two side walls 6, 7, which group defines a through hole 8 of generally parallelepipedal shape intended to receive the free end of the connection pad 1 of the device. The upper wall 4 of this holder C comprises a smooth hole 9 intended to enable the passage of a clamping screw 10, said screw 10 comprising, at one free end 10a, a portion 10b intended to enable its actuation by means of a tool provided for this purpose, while its opposite end 10c comprises a so-called clamping shoe 11 adapted to bear on the conductor to be connected when the actuating screw 10 drives it in translational movement relative to the holder C in the direction of the cable 2. It should be noted that this clamping shoe 11 is advantageously fixed to the free end 10c of the clamping screw 10 by crimping.
[0039] like Figure 5 and 6 As shown, the terminal B according to a particular embodiment of the invention comprises a notch or hole 12, 13, 14, 15 on each of its side walls 6, 7 and on each side of the holder C, which is used when the plate 16 is introduced into the holder C, as shown in FIG. Figure 7 As shown, it cooperates with a so-called intermediate plate 16 .
[0040] This intermediate plate 16 is therefore preferably made of metal and comprises two so-called first lugs 17, 18 and two so-called second lugs 19, 20 which can first be introduced into corresponding recesses 12, 13 of the cage C when the plate 16 is introduced into the end of the cage C, after which the two so-called second lugs 19, 20 can be introduced into corresponding other two recesses or holes 14, 15 of the cage C by crimping the metal plate forming the so-called second lugs, this crimping making it possible to fasten the intermediate plate 16 to the cage C. This intermediate plate 16 also comprises a smooth hole 21 intended to face the smooth hole 9 of the upper wall 4 of the cage C when the plate 16 is fixed to the inside of the cage C.
[0041] According to the present invention, and as Figures 3 to 6 As shown, this terminal B also includes a so-called nut portion 22, which is made of elastic material and includes an annular central portion 23 with a threaded hole 24. The nut 22 is used to be introduced into the retaining frame C between the upper wall 4 of the retaining frame C and the intermediate plate 16, so that the three holes 9, 24, and 21 of the upper wall 4, the nut 22, and the intermediate plate 16 are aligned respectively.
[0042] According to this particular embodiment of the invention, this nut 22 thus comprises an annular portion 23 comprising the aforementioned threaded hole 24, and two semicircular branches 25, 26, each extending around the aforementioned annular portion 23 over approximately half of its outer circumference, the two branches 25, 26 extending from the outer surface of this annular portion 23 and connected to this surface at two diametrically opposite points 23a, 23b ( Figure 2 ).
[0043] This nut 22 is mounted on and centered relative to the cage C by, on the one hand, introducing its annular portion 23 into the hole 9 of the upper wall 4 of the cage C and, on the other hand, by the compression exerted by the side walls 6, 7 of the cage C on the branches 25, 26. When screwed into the threaded hole 24 of the nut 22, the clamping screw 10 passes through the holes 9, 24, 21 in the upper wall 4 of the cage C, the nut 22 and the intermediate plate 16, respectively.
[0044] like Figure 1 , 3 As shown in Figures 10 and 11, according to the embodiment shown, the terminal comprises a so-called friction ring 33 adapted to be mounted around the annular portion 23 of the nut 22 so as to be constrained to rotate with the nut by means of grooves adapted to cooperate with portions of the nut. This ring is arranged between the annular portion and the cage for controlling the friction between the various components.
[0045] According to this particular embodiment shown in the drawings, the two branches 25, 26 are formed as a single piece with the annular portion 23. Each of the two branches 25, 26 comprises, at its free end, an element 27, 28 forming a hook extending towards the outside of the annular portion 23, these elements being intended to cooperate with recessed forms 29 to 32 formed on the inner surface of the side walls 6, 7 or material cutouts provided therefor, in the manner that will be explained below. These material cutouts are advantageously made by stamping the inner faces of the side walls 6, 7 of the cage C.
[0046] Advantageously, if Fig.13 and Fig.15 As shown, each side wall 6 , 7 comprises two material removals 29 , 30 and 31 , 32 , each forming a notch for cooperating with an element forming a hook of a branch 25 , 26 .
[0047] The so-called first of these recesses 29 , 31 has an attachment slope in cross section, said recess comprising three consecutive wall portions 29 a , 29 b , 29 c , 31 a , 31 b , 31 c which have a certain angle with respect to one another.
[0048] The other so-called second recess of these recesses 30 , 32 has an L-shape in cross section, which comprises a wall portion 30 a , 32 a substantially perpendicular to the side walls 6 , 7 of the cage C and a curved elongated wall portion 30 c , 32 c extending in the direction of the inner part of the cage C.
[0049] The recesses 29 to 32 of the two walls 6 , 7 are arranged such that a so-called first recess 29 and a second recess 30 of one wall 6 are arranged facing a so-called first and second recess 31 , 32 of the other wall 6 , 7 , respectively.
[0050] The wall portions 29a, 29b, 29c and one wall portion 29c, 31c of the so-called first recesses 29, 31 located facing the so-called second recesses 30, 32 constitute an attachment slope for the elements 27, 28 forming the hooks of the branches 25, 26.
[0051] Reference below Figures 9 to 16 The operation of the terminal according to the present invention is described.
[0052] Fig. 9 The terminal B is shown in a position in which the cable 2 is clamped. In this position, the two elements 27, 28 forming the hook are located in two so-called second recesses 30, 32, respectively, bearing against faces 30a, 32a of the recesses forming abutments perpendicular to the side walls 6, 7.
[0053] exist Fig.10 , 11and 12, terminal B is in Fig.13 and 14 Shown in the released position, before the cables have been inserted.
[0054] When the user wishes to clamp the cable 2 into the terminal B, they actuate the screw 10 by rotating it clockwise. This actuation of the screw 10 causes a translational movement of said screw 10 relative to the cage C. This screwing of the screw into the nut 22 overcomes the friction torque exerted by the elements 27, 28 forming the hooks of the branches 25, 26 on the inner surfaces of the side walls 6, 7 of the cage and overcomes the compression force exerted by these walls 6, 7 on these elements 27, 28 forming the hooks, driving the nut in rotation in the clockwise direction. During this rotation of the branches during screwing, these elements 27, 28 forming the hooks abut on the sides situated in the second recesses 30, 32 (the so-called attachment ramps) and then, after the branches 25, 26 have been bent, move to the other side of these parts. Fig.15 When the correct tightening torque is reached, a metallic click is heard. As tightening continues, a series of metallic clicks are heard.
[0055] In this position, further tightening is no longer possible, since the nut 22 is no longer held firmly enough to form a thread support.
[0056] In this position, actuation of the screw 10 in the loosening direction does not drive the nut 22 in rotation, since the elements 27, 28 forming the hooks of the branches 25, 26 are blocked in rotation by the wall portions 30a, 32a, thereby forming an abutment of the so-called second recesses 30, 32, which extend perpendicularly to the side walls 6, 7 of the cage.
[0057] Fig.16 All possible angular positions of the nut 22 during its attachment or free detachment phases are shown. At a), the screw is in a free rotation position halfway along the branches 25, 26, with no part protruding from the terminal. At b), the screw reaches a position for clamping the branches 25, 26 in the clockwise direction. At c), the screw reaches a position for unscrewing the branches 25, 26 in the counterclockwise direction.
[0058] At d), the screw is in the disengaged position after having been overlapped in the clockwise direction to clamp the branches 25, 26 or unscrewed in the counterclockwise direction to reach the disengaged position.
[0059] The present invention thus provides a clamping terminal in which an intermediate stage is formed by inserting a metal sheet or plate and a nut into the terminal, which nut disengages when screwed in once the correct clamping torque is obtained and engages when unscrewing, with an audible metallic click when the correct clamping torque is reached.
[0060] It should be noted that the cage no longer includes any threaded holes, but only smooth holes.
[0061] The helical torque is opposite to the friction torque exerted between the side wall of the cage and the end of the branch forming the hook, and the torque generated during the cooperation between the elastic branch and the inclined surface with a specific form corresponds to the compression of the branch by the wall, adding to it the friction torque, said specific form being formed by the gap created in the side wall of the cage.
[0062] Users are able to tighten the terminals with any tool without a torque wrench. Torque is controlled and the terminals no longer need the usual mechanical oversizing. The terminal section can be sized as needed.
[0063] The volume of the terminal remains unchanged. When unscrewing the screw, for example using an electric screwdriver, the screw is disengaged.
[0064] The shoe allows clamping two cables having different sections.
[0065] This terminal can be clamped to the correct torque using any 4mm hex tool from the user's tool kit.
[0066] It disengages with a series of mechanical clicks when the correct torque is reached.
[0067] The invention is advantageously applied in the field of low voltage power circuit breakers, in particular circuit breakers with molded housings. The clamping torque limiting function is integrated in the terminal. It no longer takes the form of a tool or an accessory.
[0068] Of course, the invention is not limited to the embodiments described and shown, which are given merely as examples.
[0069] On the contrary, the invention comprises all technical equivalents of the devices described and their combinations, if the latter are produced according to their concept.
Claims
1. A connection terminal for connecting an electrical conductor to a connection pad belonging to an electrical device, the connection terminal comprising a holder capable of being fixed inside a housing of the device, the holder comprising a through hole of parallelepiped shape and delimited by four walls of the holder, the through hole capable of receiving the pad, one of the walls of the holder, called the upper wall, comprising a hole capable of allowing the passage of a screw, the screw comprising, at its end located outside the holder, means for actuating the screw, and comprising, at its opposite end, a clamping shoe capable of allowing the conductor to be clamped between the pad and the shoe when the screw is actuated to drive a relative translational movement between the screw and the holder, It is characterized in that The connection terminal comprises an intermediate stage formed inside the holder C so as to allow the reception of a nut (22) having elastic branches (25, 26), which has a threaded hole (24) through which the screw (10) is screwed, the elastic branches (25, 26) interacting with forms provided on the side walls (6, 7) of the holder C so that when screwing, once the correct clamping torque is reached, the nut (22) rotates out of engagement and from the beginning to the end of unscrewing the nut (22) engages.
2. The connecting terminal according to claim 1, characterized in that: The two elastic branches (25, 26) can be radially compressed when screwed onto the inclined surfaces (29c, 31c) belonging to the retaining frame C, and the torque generated by the compression of the elastic branches (25, 26) is opposite to the torque of tightening the screw (10) until these elastic branches (25, 26) disengage from the inclined surfaces (29c, 31c) once the required clamping torque is reached.
3. The connecting terminal according to claim 1 or 2, characterized in that: It comprises means for producing a clicking sound once the above-mentioned elastic branches (25, 26) are disengaged from the inclined surfaces (29c, 31c).
4. The connecting terminal according to claim 1 or 2, characterized in that: The nut (22) comprises an annular portion (23), which comprises the threaded hole (24), through which the screw (10) passes and from which two elastic branches (25, 26) are separated, and the elastic branches (25, 26) extend circumferentially around the annular portion (23) in respective opposite directions.
5. The connecting terminal according to claim 4, characterized in that: Each resilient branch (25, 26) comprises at its free end an attachment element (27, 28) capable of cooperating with a first recessed form (29, 31) and a second recessed form (30, 32) provided on each side wall (6, 7) of the retaining frame C, each attachment element (27, 28) forming a hook which cooperates with the first recessed form (29, 31) during clamping and with the second recessed form (30, 32) during unscrewing.
6. The connecting terminal according to claim 5, characterized in that: The first recessed form (29, 31) and the second recessed form (30, 32) are made by stamping the inside of the side walls (6, 7) of the retainer C.
7. The connecting terminal according to claim 5, characterized in that: In each side wall (6, 7), a first recessed form (29, 31) and a second recessed form (30, 32) extend in a direction perpendicular to the axis X of the retaining frame C, and the two recessed forms of one side wall (6) of the side walls (6, 7) are arranged in a manner opposite to the two recessed forms of the other side wall (7).
8. The connecting terminal according to claim 5, characterized in that: Each first recessed form (29, 31) comprises a surface portion forming an attachment ramp for a second recessed form facing the same wall, the passage through this ramp (29c, 31c) for the attachment element (27, 28) to reconnect the second recessed form (30, 32) resulting in the detachment of the above-mentioned screw (10).
9. The connecting terminal according to claim 5, characterized in that: Each second recessed form (30, 32) comprises a wall portion (30a, 32a) positioned facing the first recessed form (29, 31) associated therewith, which wall portion extends perpendicularly to the axis X of the cage C and forms an abutment blocking the rotation of the nut (22) during the unscrewing operation, thereby producing engagement of the screw (10) from the beginning to the end of unscrewing.
10. The connecting terminal according to any one of claims 1 or 2, characterized in that: The intermediate stage is formed by a plate (16) mounted inside the cage (C) and crimped thereto.
11. The connecting terminal according to claim 10, characterized in that: The plate (16) comprises two first lugs (17, 18) and two second lugs (19, 20), the two first lugs (17, 18) being able to be introduced into corresponding holes (12, 13) belonging to two first edges of the two side walls (6, 7) at the end of the plate (16) being inserted into the retaining frame C, and the two second lugs (19, 20) being able to be introduced into two holes (14, 15) belonging to two second edges of the side walls (6, 7) by clamping the metal sheet of the plate (16), the second edges being opposite to the first edges.
12. An electrical protection device comprising at least one connecting terminal according to any one of claims 1 to 11.