FR2938113A1 - Electrical appliance i.e. switch, has conducting brush comprising central body, two arms projected on surfaces of central body, and operating unit cooperating with central body for pushing conducting brush towards stable position - Google Patents

Abstract

The appliance (1) has fixed contact studs (13, 14) electrically connected to two connecting terminals (21, 22), and a fixed clevis (12) electrically connected to a third connecting terminal (20). A conducting brush (15) is formed at a starting position of a folded and cut metal strip, and comprises a central body (26) articulated with the fixed clevis. Two arms (40A, 40B) are projected on surfaces (27, 28) of the central body. An operating unit cooperates with the central body for pushing the conducting brush towards a stable position.

Description

FIELD OF THE INVENTION The invention generally relates to electrical appliances of the kind comprising at least one fixed contact electrically connected to a first connection terminal, a fixed yoke electrically connected to a second connection terminal, an articulated conductive broom. to said fixed yoke and carrying at least one movable contact, and an operating member adapted to cooperate with said blade to urge it towards one or the other of two stable positions, respectively a first position where said moving contact is applied against said fixed contact and a second position where said movable contact is away from said fixed contact.

BACKGROUND TECHNOLOGY Electrical devices of this kind are already known in which the conductive broom is formed from a metal strip cut and folded, which makes them economical to manufacture.

Such a known broom comprises a central body articulated to said yoke which has a first face facing said fixed contact and a second face facing away from said fixed contact, and two arms each of a respective said face of said central body. Each of the arms has a flat main section rooted along a respective lateral edge of the body (so that from the fixed yoke one can see only one of its slices) and a second smaller section, also flat and carrying a said moving contact. This second section takes root on the end of the edge of the main section which is oriented towards the yoke, extending transversely to the main section towards the inside of the broom (so that from the fixed yoke, one sees only the one of its faces, that bearing said moving contact).

OBJECT OF THE INVENTION The invention is aimed at such an electrical appliance whose conductive brush is even more economical to manufacture and has improved performance.

To this end, it proposes an electrical apparatus comprising: at least one fixed contact electrically connected to a first connection terminal; a fixed yoke electrically connected to a second connection terminal; - A conductive broom formed from a metal strip cut and folded and comprising: - a central body articulated to said fixed yoke, said central body having a first face facing said fixed contact and a second face facing away from said fixed contact; and two arms each of a respective said face of said central body, at least one of said arms carrying a movable contact; and an operating member adapted to cooperate with said central body for biasing said brush towards one or the other of two stable positions, respectively a first position where said movable contact is applied against said fixed contact, and a second position where said moving contact is away from said fixed contact; characterized in that at least most of the face of a first said arm which joins the second face of said central body is turned away from said fixed yoke and in that at least most of the face a second said arm which joins the first face of said central body is turned away from said fixed yoke. Compared with previously known brushes, the broom that includes the electrical device according to the invention, minimizes falls in the metal strip necessary for cutting. This optimization of the percentage of useful area thus makes it possible to obtain a brush of comparable extent by using a rectangular strip having a surface (thus a quantity of material) reduced by approximately 25%.

In its flat configuration, the two arms extend parallel looking at the slice so that after their deployment, most of the face of the first (respectively second) arm that joins the second (respectively first) face of the central body is turned away from the fixed screed. This specific conformation of the brush also has the advantage of facilitating the breakage of micro-welds that can form between the fixed and movable contacts at the moment they touch and cause the closure of the circuit.

When such a weld appears, and a user acts on the operating member to tilt the blade, the weld generates a reaction force opposing the movement of the arm carrying the movable contact. In previously known brushes, this arm whose faces of the flat main section (which takes root on the central body) are oriented parallel to this reaction force, has a significant inertia modulus to bending, in other words a certain rigidity. On the contrary, in the broom which comprises the electrical apparatus according to the invention, most of the faces of the arm carrying the movable contact are oriented perpendicularly to the reaction force, so that the flexural inertia modulus is much weaker, ie the arm has a certain flexibility. Consequently, under the effect of this force, the arm flexes, which tends to cause the moving contact towards the fixed yoke, thus creating a shear force between the fixed contact and the moving contact which causes the instantaneous break (or in any case very fast) of the weld. The broom that comprises the electrical device according to the invention, therefore also reduces the effort that must exert the user to break such a weld. According to preferred features for the sake of simplicity and ease of use: said central body has an inverted T-shaped profile and comprises a flat main section and two equally flat lateral protuberances; each of said arms takes root at the end opposite to said clevis of said lateral outgrowth of said central body; said protuberances extend on either side of the plane formed by said main section and each have a same angle of inclination with said main section so that they are parallel; each of said arms carries a said movable contact and said angle of inclination is such that each of said movable contacts is centered on the median plane of said main section; each of said arms comprises a first bent section forming an internal angle whose concavity is turned towards said fixed yoke; said internal angle is between 70 ° and 90 °; each of said arms comprises a second flat, elongated section, connected by its proximal end to the distal end of said first section; said second portion of at least one of said arms carries said movable contact; each of said arms comprises a third flat section connected at its proximal end to the distal end of said second section in a transverse fold line forming a second internal angle whose concavity is turned away from said clevis; said third portion of at least one of said arms carries said movable contact; said second internal angle is such that when said mobile contact is applied against a said fixed contact, said third section carrying said movable contact is parallel to the support carrying said fixed contact; said fixed yoke comprises a central recess with a V profile; And / or each said protuberance comprises a protruding lug for translationally locking said blade relative to said central recess.

According to still other preferred features, for reasons of ease of cutting the blade and better safety of use: said electrical apparatus comprises a cylindrical piston fixed to a spring mechanically connected to said operating member, said central body further comprising a flat main section whose opposite end to said yoke is engaged in a notch of said piston, the bottom of said notch resting against a straight edge of said section opposite said yoke; said notch has a V-shaped profile; or / and - said spring is mounted in a hollow column of a driver rigidly connected to said operating member. It will be noted that the characteristics exposed in the three preceding paragraphs, are likely to be implemented in an electrical device whose conductive broom is not formed from a metal strip cut and folded and / or does not have two arms salient on both sides of the central body.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood and other advantages thereof will appear more clearly in the light of the description which follows, given solely by way of example and with reference to the appended drawings in which: Figure 1 is a plan view of an electrical apparatus according to the invention; - Figure 2 is a partial view, in elevation, of the electrical apparatus of Figure 1; FIG. 3 is a perspective view from the operating member of the conductive broom of the electrical apparatus of FIG. 1; - Figure 4 is a perspective view from the fixed yoke of the conductive broom of Figure 3; - Figure 5 is a front view of the conductive broom of Figure 3; Figure 6 is a plan view of the conductive broom of Figure 3; - Figure 7 is a plan view of the metal strip cut from which is obtained the conductive broom of Figure 3; FIG. 8 is a detailed perspective view showing the articulation zone between the conductive brush and the driver of the electrical apparatus of FIG. 1; and FIG. 9 is a view similar to FIG. 3 of a variant of the conductive brush of FIG.

DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT The electrical apparatus 1 illustrated in FIGS. 1 and 2 is of the switch type, here a back and forth. It comprises a housing 10 made of insulating material (FIG. 1), an operating member 16, a conductive broom 15 (FIG. 2) hinged to a fixed yoke 12, itself a conductor, and two fixed contact pads 13 and 14.

The conductive broom 15, under the control of the operating member 16, is adapted to occupy alternately two stable positions: a first position illustrated in FIG. 1 where, by a first contact bead 17, it is applied against the first fixed contact pad 13 and is away from the second fixed contact pad 14; and a second, non-illustrated position, where, by a second contact ground 18, it is applied against the second fixed contact pad 14 and is away from the first fixed contact pad 13. The two fixed contact pads 13 and 14 have a rounded boss which can also be a raised boss, silver or silver metal. They are arranged, each respectively, and symmetrically, on either side of the fixed yoke 12. The latter and the fixed contact pads 13 and 14 are each connected to a hole connection terminal, 20, 21 or 22 for their connection to an electrical conductor. In the embodiment shown in Figure 2, the fixed yoke 12 and the pads 13 and 14 are integral with their respective connection terminal.

According to a variant not shown, the fixed contact pads are separate parts of the connection terminals to which they are associated, being properly electrically connected thereto. According to another variant not shown, the connection terminals are of a different type, for example tab, or other, allowing direct engagement of the conductors concerned or a quick connection thereof. Furthermore, for a use of the simple switch type, one of the terminals 21 or 22 and the corresponding fixed contact pad 13 or 14 are omitted or unused. According to the invention, the fixed yoke 12 has a central recess 25 with a V profile extending transversely to the axis connecting the two fixed contact pads 13 and 14. As shown in isolation in FIGS. Conductive broom 15 is a piece that comes in one piece from a rectangular metal strip, suitably cut and folded (Figure 7). It comprises a central body 26 and two arms 40A and 40B protruding on either side of the same body 26 and carrying, at their respective ends, the contact grains 17 and 18.

The central body 26 which has an inverted T-shaped profile, thus comprises a flat main section 30 and two lateral protuberances 35A and 35B also flat. It is pivotally mounted in the recess 25, its first face 27 being turned towards the arm 40A (and the fixed contact pad 13) and its second face 28 is turned towards the arm 40B (and the fixed contact pad 14). The main section 30 which has a rectangular contour, and has at each of its two longitudinal ends, a straight edge 33, 34; the wafer 34 constituting the pivot axis of the wiper 15 in the central recess 25 (Figure 4).

The two protuberances 35A, 35B which have a generally square outline, take root along a respective fold line 36A, 36B, from the edge 34 of the section 30 and about one third of its height.

They extend on either side of the plane formed by the section 30 and have the same angle of inclination a with the latter, so that they are parallel to each other (Figure 6). The angle α which in this case is approximately 165 °, is such that the two movable contact beads 17 and 18 are centered on the median plane 37 of the section 30 (FIGS. 5 and 6). In variants not shown, the arms are shorter and the angle is smaller or on the contrary, the arms are longer and the angle is greater. Furthermore, to lock the brush 15 in translation against the recess 25, a lug 38A, 38B protrudes from each protrusion 35A, 35B at the corresponding fold line 36A, 36B. Each lateral arm 40A, 40B comprises, from the central body 26, a first elbow section 41A, 41B, a second flat rectangular section 42A, 42B of the same width as the section 41A, 41B, and a third square section 15 also flat 43A, 43B slightly wider than the sections 41A, 41B and 42A, 42B, so that it projects slightly inwardly of the blade 15. The first elbow section 41A, 41B is connected by its proximal end to the end opposite to the fixed yoke 12 of the protrusion 35A, 35B and forms an internal angle R (FIG. 2), here about 80.degree., the concavity of which is turned towards the yoke 12. The second rectangular section 42A, 42B is connected by its proximal end at the distal end of the elbow section 41A, 41B and extends towards the fixed contact pad 13, 14. The third section 43A, 43B (which carries the movable contact bead 17, 18 in silver or silver metal for its cooperation with the stud of c fixed contact 13, 14) is connected by its proximal end to the distal end of the rectangular section 42A, 42B, in a transverse fold line 45A, 45B forming an internal angle y (here about 170 °) whose concavity is turned away from the fixed yoke 12 (Figures 3 and 5). This angle is such that when the movable contact bead 17, 18 is applied against the fixed contact pad 13, 14, the section 43A, 43B is parallel to the support carrying the pad 13, 14 (Figure 2).

Moreover, as illustrated in FIGS. 1 and 6, the major part (here, that corresponding to the sections 42A and 43A) of the face 46 of the arm 40A which joins the second face 28 of the central body 26 is turned away from the the fixed screed 12.

Similarly, the majority (here, that corresponding to sections 42B and 43B) of the face 47 of the arm 40B which joins the first face 27 of the central body 26 is turned away from the fixed yoke 12. In the configuration to flat of the blade 15 shown in Figure 7 (that is to say after the cutting of the strip but before the folding operations and deployment of the arms), the two arms 40A, 40B extend parallel to each other. another in the extension of the protuberances 35A, 35B and on either side of the section 30. Compared to the flat configuration of a conventional broom in which the arms extend crosswise on both sides of the body central, that of the brush 15 minimizes the amount of lost material. Thus, while maintaining the same kinematics and the same operating environment, the blade 15 is obtained from a rectangular strip with reduced dimensions, providing a surface gain and therefore material of the order of 25%.

The transition from the flat configuration to the three-dimensional configuration of the blade 15 is carried out as follows. The first step consists of folding the two protuberances 35A and 35B on either side of the section 30 along the angle a. Then, each of the arms 40A and 40B is deployed on either side of the central body 26 so as to form the elbow sections 41A and 41B of internal angle R. Finally, the respective end of each arm 40A, 40B which carries the movable contact 17, 18 is slightly folded towards the right edge 33, so as to form the fold line 45A, 45B of internal angle y and the sections 42A, 42B, and 43A, 43B. Of course, alternatively, the order of these steps can be changed without this changing the final conformation of the brush.

The drive means of the brush 15 will now be described. The end of the section 30 opposite to the wafer 34 is adapted to cooperate with a driver 54, rigidly connected to the operating member 16, and comprising a hollow pin 53 in which is mounted a spiral spring 52. A cylindrical piston 51 of insulating material is fixed at one of its ends to the spring 52, and has at its other end a notch 50 with a V profile which is engaged in the main section 30, so that the bottom of this notch 50 is in abutment against the right edge 33 of this section 30 and the spring 52 is compressed. When an operator acts on the operating member 16, the piston 51 causes the tilting of the section 30 and therefore that of the brush 15 which passes from one to the other of its stable positions. At the moment when the movable contact bead 17, 18 touches the fixed contact pad 13, 14 and causes the closing of the circuit, it can happen that an electric arc is generated and that a micro-welding is formed between these two contacts . The specific conformation of the conductive brush 15 makes it easier to break these micro-welds. Indeed, when the user of the electrical apparatus 1 acts again on the operating member 16, the welding provides a resistance to the movement of the blade 15 which causes the elastic deformation of the arm 40A, 40B carrying the movable contact bump 17, 18, so that the latter slides towards the fixed yoke 12 Compared to the more rigid conventional brushes, the blade 15 allows a much greater bending of the arms 40A and 40B, which generates a shearing force between the grain movable contact 17, 18 and the fixed contact pad 13, 14 causing the instantaneous break (or in any case very fast) of the weld. The arm 40A, 40B then returns to its original conformation and the movement of the blade 15 continues (the movable contact bead 17, 18 then having a circular path).

We will now describe, in support of Figure 9, an alternative embodiment of the brush and connection means between the brush and the actuator. For the common elements of the brush (protrusions 35'A, 35'B of the central body 26 'and arms 40'A, 40'), the same reference numerals have been used, to which only one '. The brush 15 'is distinguished from the brush 15 only by its main section 30' which extends towards the actuating member by a semicircular stud 60.

The driver cooperating with the brush 15 'differs from the coach 54 in that it does not include a piston such as 51. Its spring is thus directly in contact with the edge 33' of the section 30 ', while a portion of the pin 60 penetrates inside this spring. This variant requires, for its implementation, a particular attention to the cutting of the brush 15 'to avoid the presence of machining burrs on the edge 33' which could cause inadvertent hooking of the spring on the section 30 ' . According to other variants not shown, the third section carrying the movable contact has a different contour, for example rectangular, and / or a width identical to that of the second rectangular section. According to yet another variant not shown, each arm has after the elbow section, only one elongate flat section carrying the movable contact bump.

Moreover, for a use of the simple switch type, one of the mobile contact grains is omitted or unused. Many other variants are possible depending on the circumstances, and it is recalled in this regard that the invention is not limited to the examples described and shown.

Claims (17)

REVENDICATIONS1. Electrical apparatus comprising: - at least one fixed contact (13, 14) electrically connected to a first connection terminal (21, 22); - a fixed yoke (12) electrically connected to a second connection terminal (20); - a conductive broom (15; 15 ') formed from a metal strip cut and folded and comprising: - a central body (26; 26') hinged to said fixed yoke (12), said central body (26; ') having a first face (27) facing said fixed contact (13) and a second face (28) facing away from said fixed contact (13); and - two arms (40A, 40B, 40'A, 40'B) each projecting from a respective said face (27, 28) of said central body (26; 26 '), at least one of said arms (40A 40B; 40'A, 40'B) carrying a movable contact (17, 18); and an actuating member (16) adapted to cooperate with said central body (26; 26 ') for biasing said brush (15; 15') towards one or the other of two stable positions, respectively a first position where said movable contact (17, 18) is applied against said fixed contact (13, 14), and a second position where said movable contact (17, 18) is away from said fixed contact (13, 14); characterized in that at least the major part of the face (46) of a first said arm (40A; 40'A) which joins the second face (28) of said central body (26; 26 ') is turned opposite said fixed yoke (12) and in that at least the major part of the face (47) of a second said arm (40B; 40'B) which joins the first face (27) of said central body ( 26; 26 ') is turned away from said fixed yoke (12). 2. The electrical apparatus as claimed in claim 1, characterized in that said central body (26; 26 ') has an inverted T-shaped profile and comprises a flat main section (30; 30') and two equally flat lateral protuberances (35A). 35B, 35'A, 35'B). 3. Electrical apparatus according to claim 2, characterized in that each of said arms (40A, 40B; 40'A, 40'B) takes root at the end opposite to said yoke (12) of said lateral outgrowth ( 35A, 35B; 35'A, 35'B) of said central body (26; 26 '). 4. Electrical apparatus according to claim 3, characterized in that said protuberances (35A, 35B, 35'A, 35'B) extend on either side of the plane formed by said main section (30; 30 '). and each have the same angle of inclination (a) with said main section (30; 30 ') so that they are parallel. 5. Electrical apparatus according to claim 4, characterized in that each of said arms (40A, 40B, 40'A, 40'B) carries a said movable contact (17, 18) and in that said angle of inclination (a ) is such that each of said movable contacts (17, 18) is centered on the median plane (37) of said main section (30; 30 '). 6. Electrical apparatus according to one of claims 1 to 5, characterized in that each of said arms (40A, 40B, 40'A, 40'B) comprises a first bent section (41A, 41B) forming an internal angle ( R) whose concavity is turned towards said fixed yoke (12). 7. Electrical apparatus according to claim 6, characterized in that said internal angle (R) is between 70 ° and 90 °. 8. Electrical apparatus according to one of claims 6 or 7, characterized in that each of said arms (40A, 40B, 40'A, 40'B) comprises a second flat section, elongated, (42A, 42B) connecting by its proximal end to the distal end of said first section (41A, 41B). 9. Electrical apparatus according to claim 8, characterized in that said second portion of at least one of said arms carries said movable contact. 10. Electrical apparatus according to claim 8, characterized in that each of said arms (40A, 40B, 40'A, 40'B) comprises a third flat section (43A, 43B) connected by its proximal end to the end. distal of said second section (42A, 42B) along a transverse fold line (45A, 45B) forming a second internal angle (y) whose concavity is facing away from said yoke (12). 11. Electrical apparatus according to claim 10, characterized in that said third section (43A, 43B) of at least one of said arms (40A, 40B, 40'A, 40'B) carries said movable contact (17). , 18). 12. Electrical apparatus according to claim 11, characterized in that said second internal angle (y) is such that when said mobile contact (17, 18) is applied against a said fixed contact (13, 14), said third section (43A, 43B) carrying said movable contact (17, 18) is parallel to the support carrying said fixed contact (13, 14). 13. Electrical apparatus according to one of claims 1 to 12, characterized in that said fixed yoke (12) comprises a central recess (25) V-profile. 14. Electrical apparatus according to claim 13, characterized in that each said protuberance (35A, 35B, 35'A, 35'B) comprises a lug (38A, 38B) projecting to lock in translation said blade (15; 15 ') relative to said central recess (25). 15. Electrical device according to one of claims 1 to 14, characterized in that it comprises a cylindrical piston (51) fixed to a spring (52) mechanically connected to said actuating member (16), said central body (26) further comprising a flat main section (30) whose opposite end to said yoke (12) is engaged in a notch (50) of said piston (51), the bottom of said notch (50) resting against a straight edge (33) ) of said section (30) opposite said yoke (12). 16. Electrical apparatus according to claim 15, characterized in that said notch (50) has a V-shaped profile. 17. Electrical apparatus according to one of claims 15 or 16, characterized in that said spring (52) is mounted in a hollow column (53) of a driver (54) rigidly connected to said actuating member (16) .30