EP0072285A1 - Opening device for mobile contacts of contactors able to limit short circuit currents - Google Patents

Abstract

Threshold coupling device to release moving contacts of circuit breakers when short circuits appear. A blade of rectangular section (13) with longitudinal faces 13 ', 13 "associated with a contact carrier (10) is provided with balls (29, 30) which cooperate with an elastic clamp (33) to achieve a mechanical connection with threshold between the contact (6) and an operating member (1, 2) carrying this clamp This coupling is advantageously used in limiting circuit breakers.

Description

The invention relates to a device for automatically releasing the mobile contacts of a load cut-off device such as a contactor capable of limiting short-circuit currents and in particular using the electro-dynamic repulsion which appears between conductors of current, in which a movable contact carrier has a longitudinal attachment piece which is integral with a contact bridge subjected to these repulsive forces and which is connected to an operating member of the contactor by means of a coupling at the threshold, this coupling comprising members of convex shape which cooperate transversely with respect to the longitudinal axis, and resiliently with notches to establish a predetermined longitudinal holding force between the bridge and the operating member.

In a known device, a guide is used for the longitudinal attachment piece which is produced in the form of a sliding sleeve around and along the operating member, which gives the coupling large transverse dimensions relative to the useful length of the electrical conductors which must cause electro-dynamic forces of repulsion.

Furthermore, this device is placed on the side opposite to the power take-off of the operating member with respect to the contacts, and occupies a large volume which encroaches on the volume of the arc extinguishing chambers usually associated with conductors.

In another known device, use is made of means for guiding the contact carrier which are bulky, since the operating member must here also guide the attachment part; although the coupling is here placed more favorably, it uses several compression springs which take, because of their lateral arrangement, a large volume; furthermore, no special precautions have been taken to guarantee good insulation.

The invention therefore proposes to provide a contact release device whose general constitution corresponds to that which is mentioned above but in which measures will be taken on the one hand to reduce the volume of the threshold coupling, and on the other hand to improve fidelity, sensitivity, and speed.

• La figure 1 représente en élévation une coupe par tielle de l'appareil recevant le dispositif, par le plan SS',
• La figure 2 illustre une vue en élévation et en coupe partielle par SS' du rateau recevant le dispositif,
• La figure 3 représente une vue de côté du dispositif d'accouplement en coupe par un plan NN' perpendiculaire à SS',
• La figure 4 montre une vue de dessus du dispositif en coupe par un plan RR' passant par la cage,
• La figure 5 montre un second mode de réalisation d'un couvercle de fermeture,
• La figure 6 illustre une vue en coupe NN' simplifiée de l'accouplement après disjonction,
• La figure 7 représente en vue de côté et en coupe par le plan NN' la variante de réalisation de l'organe de manoeuvre comportant un dispositif d'accouplement selon la figur.e 10,
• La figure 8 illustre en coupe NN' une région de l'organe de manoeuvre dépourvu de sa pince d'accouplement et avec un couvercle partiellement arraché,
• La figure 9 montre une vue de dessous de l'organe de manoeuvre dépourvu de ses dispositifs d'accouplement,
• La figure 10 représente une vue extérieure en élévation d'une variante d'organe de manoeuvre,
• Les figures 11 et 12 représentent en élévation coupée et respectivement en vue de côté extérieure un porte-contact équipé d'une pièce d'accrochage, et
• La figure 13 illustre une vue partielle en élévation et en coupe par un plan SS' de l'organe de manoeuvre selon la figure 10, équipé de pivots et d'un couvercle.

According to the invention, this result is achieved thanks to the fact that the attachment piece is constituted by a metal blade of rectangular section having at one end opposite the contacts, a tubular cage of transverse axis in which are housed with play two balls supported one on the other and having spherical surface portions outside the cage, while the operating member comprises a housing in which is placed an elastic clamp comprising two levers, pivoting, placed substantially parallel to the parallel faces of the blade, and on either side thereof, each of the first two branches of these levers being provided with an opening or notch placed opposite a portion of ball surface, while two second opposite branches of these levers placed opposite one another, are subjected to opposite forces developed by the same compression spring with a transverse axis. Other measures aimed in particular at facilitating the installation of the device and at improving the isolation will be better understood on reading the description below which is accompanied by 13 figures, among which:

• Figure 1 shows in elevation a section through tial of the device receiving the device, by the plan SS ',
• FIG. 2 illustrates a view in elevation and in partial section through SS ′ of the rake receiving the device,
• FIG. 3 represents a side view of the coupling device in section through a plane NN 'perpendicular to SS',
• FIG. 4 shows a top view of the device in section through a plane RR 'passing through the cage,
• FIG. 5 shows a second embodiment of a closure cover,
• FIG. 6 illustrates a simplified sectional view NN ′ of the coupling after disjunction,
• FIG. 7 represents in side view and in section through the plane NN ′ the alternative embodiment of the operating member comprising a coupling device according to FIG. 10,
• FIG. 8 illustrates in section NN ′ a region of the operating member devoid of its coupling clamp and with a cover partially torn off,
• FIG. 9 shows a bottom view of the operating member devoid of its coupling devices,
• FIG. 10 represents an external view in elevation of a variant of an operating member,
• Figures 11 and 12 show in elevation cut and respectively in external side view, a contact carrier equipped with a hooking piece, and
• FIG. 13 illustrates a partial view in elevation and in section through a plane SS ′ of the operating member according to FIG. 10, equipped with pivots and with a cover.

A device for actuating the movable contacts 6 - 7 - 8 of an apparatus according to the invention and visible in particular in FIG. 1, comprises a rake 1, which constitutes the device for operating the movable contacts, and for example when it is an integral part of a contactor capable of limiting short-circuit currents, a movable armature 2 belonging to an electromagnet not shown, and intended to operate the contacts. Such a rake could be controlled by other means, such as a mechanical lock with automatic opening in the event of overload, or possibly with manual control, if the rake controls the contacts of a circuit breaker.

A lower region l ′ of this rake and of this armature are associated for example by means of a pin 26 placed transversely with respect to the direction of longitudinal movement F of the armature, the lateral guiding being carried out by means not represented.

This rake comprises three identical hollow portions or columns 3 - 4 - 5 linked together in a lower region 1c and each associated with one of the contact systems cutting each of the phases of a polyphase supply line.

Each movable contact, 6 - 7 - 8, preferably consisting of a contact bridge, cooperating with two fixed contacts not shown is placed in a particular contact holder 10 - 11 - 12 which is guided in the housing 9 of the apparatus using means not shown in detail, which provide it with a neck direction smoothing F. These contact carriers 10 - 11 - 12 are located at the top of the figure and each have a respective hooking piece 13 - 14 - 15 which is directed towards the bottom of the figure and which enters respectively one of the three hollow portions 3 - 4 - 5.

A more detailed view of the rake 1 shows in FIGS. 2 and 3 that each column has a clean housing 16 respectively 17 respectively 18 suitable for receiving coupling devices 21 - 22 - 23 cooperating with the hooking pieces 13 - 14 -15 .

Each housing such as 16 is composed of an upper volume such as 19 open at 19 'at the top of the column 3 and of a lower volume such as 20, the coupling devices 21 - 22 - 23 being arranged respectively in each of these lower volumes to cooperate with each of the corresponding attachment parts; a cover 24 closes off the lower volumes of the housings such as 20 which each open into the same chamber 25 open towards the bottom of the figure and receiving, for example, the frame 2 and the pin 26.

A coupling device, which is in particular visible in FIG. 3 and in FIG. 4, is intended to open to release the attachment piece which is associated with it and thus to allow the corresponding mobile contact to be rapidly expelled towards the top of the figure when the electro-dynamic forces to which it is subjected exceed a certain threshold, so as to limit the intensity of the currents which circulate in the contact bridge, and consequently, in the line concerned. The lower end 27 of a blade 13, which constitutes a hooking piece visible in FIGS. 1, 2 and 3, and which is opposite to the contact 6 and to the contact carrier 10, has a tubular cage 28 of axis XX 'transverse to F, in which are arranged with play two balls 29 - 30 so that when these are in contact with one another parts of their spherical surface 31 respectively 32 opposite are placed outside from the cage; the cage 28 itself has a length m - greater than the thickness n of this blade and an internal diameter which allows rolling and transverse movement of the balls (see FIG. 4); this blade 13 is of rectangular section, with faces 13 '- 13 ", parallel, the second dimension p of its section being several times greater than its thickness n. It will be observed that the three blades 13 - 14 - 15 have their largest faces 13 '- 13 "parallel to a plane SS', passing through the three portions 3 - 4 -5 of the rake, which further improves the volume occupied when the device is used in a polyphase circuit breaker.

The coupling device 21 placed in the housing 20 comprises a clamp 33 formed by two opposite pivoting levers 34, respectively 35, which are placed substantially parallel to the plane SS 'and which oscillate around respective transverse pivots 36 - 37 placed parallel to each other and to the plane SS 'and perpendicular to F.

Furthermore, these pivots are fixed. by their ends 38 - 39 respectively 40 - 41 in two opposite parallel walls 42 - 43 of a prismatic cage 44 formed by a sheet bent in a U whose bottom 45, common to the two walls, is supported on flanges 46 - 47 of the lower volume 20, which limit the latter relative to the upper volume 19, while the outer edges 48 - 49 of these walls directed towards the chamber 25 are in abutment on the cover 24.

The bottom 45 of this cage 44 also has an opening 50 which gives passage to the blade 13 and to the ends 51 - 52 of the clamp. The pivots 36 - 37 define on either side of them two first branches 34 '- 35' and two second branches 34 "- 35", the first being oriented towards the upper volume 19 and the second towards the chamber 25. The width of these levers is slightly less than the interior distance separating two walls of the cage to allow their oscillation around the pivots.

The first branches 34 '- 35' have opposite ends 51 - 52 which are cambered in a divergent manner, and each comprise between the first end and the pivot an opening or notch 53 - 54, of contour for example circular, while the second branches placed opposite are subjected to opposite forces developed by the same compression spring 55 of transverse axis YY ', which is supported on respective second ends 56 - 57 opposite the first ends to cause a torque of approximation of the first ends 51 - 52.

When the blade 13 is engaged deep enough in the clamp, the surfaces 31 - 32 of the balls engage in the openings 53 - 54 and operate a longitudinal maintenance of this blade by the coupling device 21 and therefore by the rake 1 in the direction F so that the movements of the latter are faithfully transmitted to the contact carrier. In this hooked position, the blade 13 passes between the two pivots 36 - 37 with little play, which gives it lateral guidance.

In the embodiment visible in FIG. 3, the second ends 56-57 and the spring 55 are placed in an opening 58 of the cover 24; this arrangement which saves space is not limiting, because a thicker cover 59 shown in a variant in FIG. 5 could only have a blind clearance 60 to receive these ends.

It can be seen in FIGS. 2 and 3 that an insulating plate 61 or more insulating layers are placed between the cover 24 and the frame 2 to provide sufficient isolation between this frame and the metallic parts of the coupling which are or which may be at the same potential as the contact bridge.

This isolation is not necessary if a completely closed cover such as 59 is used.

It is also possible to use, instead of a single cover 24, several individual covers to close off the volumes such as 20 and maintain each of the clamp devices 22 - 21 - 23.

In the coupling position shown in Figure 2 it is further noted that a lower end 62 of the blade 13 passes on either side of the spring 55 thanks to a longitudinal notch 63 thereof. This end is in the form of a fork whose arms 64 - 65 have at their tips inclined ramps 66 - 67, which facilitate the introduction of the blade into the clamp. The way in which the blade 13 is guided, on the one hand between the pivots 36 - 37, and on the other hand between the openings 53 - 54 along the balls gives this coupling device the possibility of tolerating slight angular misalignments between the longitudinal axis of the blade and the axis of the corresponding column. The opposite forces applied to the balls in the XX 'direction thanks to the torque developed by the spring 55, as well as the penetration of the balls in the notches or openings 53 - 54 in position I, provide a holding effect of the blade 13 by the clamp 33 in direction F.

For a particular arrangement of the balls and notches, these forces can be overcome when a determined traction of direction G is applied to the blade 13, and that the clamp 33 is held in position, for example when the armature 2 is attracted against the cylinder head of the electromagnet.

When, as a result of the application to the blade of a force coming from the electro-dynamic repulsion communicated in the direction G to the contact bridge, which is greater than a determined threshold, the coupling has been opened, the blade 13 is placed in a position II visible in FIG. 6, which corresponds to the position where the contact bridge has been expelled and for which the surfaces 31 - 32 of the two balls 29 - 30 lie on the one hand against two internal flat surfaces 68 - 69 of the levers which are substantially parallel, and on the other hand, in the vicinity of the edges 70 - 71 which define the origin of the arched ends 51 - 52.

Stops 72 - 73 placed opposite and carried by stiffening flanges 74 respectively 75 of the levers, bent at right angles to these surfaces 68 - 69, make it possible to limit the movement of approach of the ends 51 - 52 when the blade n is not engaged in the clamp, as it appears when mounting the device.

A fall of the balls cannot therefore occur in this position and a new attachment position can be obtained by operating a relative movement of approach in the opposite direction of G between the blade and the clamp during which the balls first roll on surfaces 68 - 69, then snap into openings 53 - 54.

Due to the parallelism of the surfaces 68 - 69, the coupling process between the blade 13 and the clamp 33 takes place practically without any resistant force appearing in the direction opposite to G.

However, one can give a spacing to the two pivots such that for the uncoupled position, the two surfaces 68 - 69 converge slightly towards a common line placed in the plane SS '.

If this line of convergence of the two surfaces were placed above the pivots, the blade 13 would tend to be biased towards the pivots, which would be advantageous for example for the establishment of a new coupling which would be obtained automatically by an upward movement of the figure direction G, of the armature under the effect of return springs 2 '- 2 "thereof in the rest position, see also FIG. 1.

If on the contrary, the line of convergence of the surfaces 68 - 69 was placed below the pivots, the blade 13 would tend to be pushed back in direction G, which would be advantageous to stabilize the contact carrier, in an open position by damping the possible effects of its impact on the top of the housing during a trip.

The embodiment of the clamp and of the blade which has just been described, can be used in a switching device of the same general structure, but having different shapes as can be seen in FIGS. 7 and 10.

In this polyphase device, there is a rake, or operating member 80 which also includes several hollow columns 81 - 82 -83 placed in parallel.

A column such as 81 has an internal well 84 having an upper space 85 which opens at 86 at the upper end of this column, an intermediate space 87 and a lower space 88 which opens into a chamber 89, common to several wells column 84 - 91 - 92, see Figure 10; the neighboring lower spaces 88 - 93 - 94 of the three columns are separated by insulating partitions 95 - 96 which stop at the level of the lower space, see also FIG. 9.

A clamp 97 similar to the previous clamp 33 is housed in the intermediate space 87 to cooperate with a rectangular blade 98 which is identical to the blade 13 and which passes through the column.

The only modification of this clamp resides here in the implementation, between the ends 99 - 90 of levers 100 - 103 of clamp 97, of an adjustment screw 101 which makes it possible to adjust the tension of the common spring 102 by a displacement YY 'axis, to adjust the threshold opening threshold coupling.

The two clamp levers 100 - 103 pivot here again on two parallel pivots 104 - 105 whose fixing of the ends, such as 106 - 107 see Figures 8 and 13, is obtained differently than in the previous case.

Each lower space 88 respectively 94 and 93 has on internal surfaces 108 respectively 109 of side walls 110 respectively 111 of the rake, as well as on internal surfaces 112 respectively 113 and 114 - 115 of partitions 95 - 96, pairs of parallel grooves such than 116 - 117, 118 - 119, 120 - 121 and 122 - 123, see Figures 8, 13 and 9.

These grooves which run parallel to the axis F of a column end at the limit of the corresponding intermediate space, for example at 124 - 125 for space 88, in order to receive the ends 106 - 107 respectively 126 - 127 pivots 104 - 103.

A common insulating cover 130 has in each lower space a prismatic tank such as 128 respectively 129 whose opposite walls parallel to the axis of the well support by their upper edges such as 131-132 see Figure 13, the ends of the pivots. The solid bottom 133 of this insulating cover 130 serves as in the previous case to isolate each coupling device from an armature 134 of an electromagnet which is held in the chamber 89 by a pin 135.

In an embodiment of contact holder 163 illustrated in FIGS. 7, 11 and 12, the attachment blade 98 has at its upper part 136 two lateral ears 138 - 137 which penetrate into openings 139 - 140 of two parallel metal uprights 141 - 142 to which these ears are attached.

These uprights have two other openings 143, respectively 144 which are placed above the previous ones and in the same median plane SS 'to hold a U-shaped magnetic piece 165 having a crosspiece 147 placed in the vicinity of 136, two parallel branches 148 - 149 of which the portions 145 - 146 penetrate into the openings 143 - 144 and a slot 170 placed in a plane NN 'perpendicular to SS'.

Upper ends 160 - 161 of the uprights are interconnected by a plastic coupling part 162 and by a transverse key 157, this part 162 advantageously serving to effect the upper guide of the contact carrier and to serve as a stop means against an upper stop surface 164 of the apparatus housing which will determine for example position II.

Between these upper ends 160 - 161 and openings 143 - 144 are placed in the same plane SS ', two parallel longitudinal grooves 166 - 167 which guide a contact pusher 155 returned to the bottom of the figure by a contact pressure spring 156. This pusher rests axially on the upper edge of the central region 150 of a contact bridge 151, see FIG. 7, and maintains it transversely thanks to the notches 153 - 154.

The contact pads 11 - 172 of the bridge 151 are applied to fixed contacts 173 - 174 carried in a known manner by conductors 175 - 176 circulating in part parallel to the contact bridge.

The central region 150 is placed in the slot 170 of the magnetic piece 165 so as to cooperate with the latter by electromagnetic means when the contact bridge 151 is crossed by large currents.

These currents, which are much lower than those which show repulsion forces on the contact bridge in the direction G, cause an attraction of the contact bridge by the magnetic part in the opposite direction to G.

In the embodiments illustrated, the blades such as 13 have a flat rectangular section which makes it possible to lighten the mass of a contact carrier as much as possible so that its expulsion by the forces of repulsion is extremely rapid and so that the limitation of the currents which have caused it is effective; it is clear that the use of a blade having a different section, for example square or round would lead to an increase in the mass of the contact carrier and therefore a deterioration in performance without departing from the scope of the invention.

The contact release device which has been illustrated in a case where it is used in a contactor capable of limiting short-circuit currents can advantageously be applied to a circuit breaker-limiter having means in place of an electromagnet automatic rake control mechanisms which release the rake upon the appearance of overloads, these mechanical means being able to be armed and rearmed by manual control.

In such a circuit breaker-limiter device, a small rake could also be used for each of the phases, which would include a single release device capable of operating independently of the others.

One can also use a contact release device comprising a clamp system as described above but fixed in a housing, and a coupling blade secured to a contact carrier, when it is desired to constitute a stage of 'repulsion limit switch which can also be associated with a suitable contactor.

When the contact release device, associated with a contactor, is called to be reset automatically, this reset is effected by the movement of the armature which, under the effect of its own return springs, again engages the notches clamps on the balls, the contact carrier then being placed in abutment against an upper surface of the housing which operates simultaneously and using appropriate means, damping the movement of the contact carrier and keeping it in a high position.

If the contact release device has to be reset manually, it is possible either to provide a mechanical movement or rake which is equivalent to that communicated by the contactor armature described above, (for example in the case of 'a circuit breaker), either provide at the top of the housing an opening through which external manual means may act in the opposite direction to G on the upper end of the contact carrier, such as part 162, (for example in the case of a switch-limiter stage).

Claims (9)

1. Device for automatically releasing the mobile contacts of a cut-off device under load in particular current limiting, using the electro-dynamic repulsion which appears between conductors and in which a longitudinally movable contact carrier has a longitudinal hooking piece which is integral with a contact bridge subjected to these repulsive forces and which is connected to a device operating member by means of a threshold coupling, this coupling comprising convex shaped members which cooperate transversely by relative to the longitudinal axis, and elastically with notches to establish a predetermined longitudinal holding force between the bridge and the operating member,
characterized in that the attachment piece is constituted by a metal blade of rectangular section 13 with longitudinal parallel faces (13 ', 13 ") having at one end (27), opposite the contact (6), a tubular cage (28 ) of transverse axis (XX '), in which are housed with play two balls (29, 30) supported one on the other and having spherical surface portions (31, 32) outside the cage (28) while the operating member (1) comprises a housing (20) in which is placed an elastic clamp (33) comprising two pivoting levers (34, 35) placed substantially parallel to the parallel faces of the blade (13), and on either side of it, each of the first two branches (34 ', respectively 35') of these levers (34, respectively 35) being provided with an opening or notch (54, respectively 53) placed opposite a portion of ball surface (31 respectively 32) while two second branches (34 ", respectively 35") of these levers, placed opposite one another, are subjected to opposite forces developed by the same compression spring (55) with a transverse axis (YY ') parallel to the axis XX' of the cage. 2. contact release device according to claim 1, characterized in that the levers (34, 35) are mounted on two parallel pivots (36, 37) whose ends (38, 39 respectively 40, 41) rest in two parallel walls (42, 43) - of a metal cage U-shaped prismatic (44) of which an opening (50) in the bottom (45) directed towards the contact (6) is crossed by the hooking piece (13) and by first ends (51, 52) of the levers, which are divergent and are oriented towards contact. 3. contact release device according to claim 2,
characterized in that the end (27) of the attachment piece (13) penetrating into the cage (44) extends to the vicinity of the common spring (55). 4. device for releasing contacts according to one of claims 1 to 3,
characterized in that the ends (99, 909 ') of the levers, opposite the first ends, are separated by a common compression spring (102) whose tension can be adjusted by a screw (101) movable coaxially with the spring. 5. Device for releasing contacts according to one of claims 2 to 4,
characterized in that in a position II of the blade (13), resulting from the opening of the clamp (33) the external surfaces (31, 32) of the balls are in contact with planar surfaces (68, 69) which belong to the levers (38, 39) and which are placed between the openings (53, 54) and the diverging ends (51, 52). 6. contact release device according to one of claims 2 to 5,
characterized in that the housing (20) of the operating member (1) receiving the prismatic cage (44) is placed between on the one hand a first volume (19) which is placed on the contact side (6) and which is crossed by the attachment part (13), and on the other hand a chamber (25) which receives an armature (2) electromagnet, a cover (24) being placed between this chamber and the prismatic cage to fix the latter in the housing (20), and insulating means (61, respectively 59) _' being arranged between the cage (44) and the frame (2). 7. Contact release device according to one of the preceding claims, and applied to a polyphase circuit breaker, characterized in that the large parallel faces (13 ', 13 ") of each of the blades (13, 14, 15) are placed parallel to the same plane SS 'passing through all of the housings (84, 91, 92) of hollow columns (81, 82, 83) belonging to a common rake (80). 8. Device for releasing contacts according to one of claims 1 to 7,
characterized in that one end (136) of the blade (98) opposite the tubular cage (28) is integral with two parallel metal uprights (141, 142) which are provided with fixing means (143, 144) for a workpiece magnetizable U-shaped (165) cooperating by attraction with a contact bridge (151) which is placed between these uprights and which is subjected to the elastic action (156) of a pusher (155) guided between these uprights. 9. contact release device according to one of claims 1, 3, 4, 5, 7 or 8,
characterized in that the pivots (104, 105) of the levers (100, 103) of the clamp (97) are held in longitudinal grooves (116, 117) of the operating member (80) by an insulating cover (130 ) placed between the clamp (97) and an opening (89) of this operating member, which is opposite to the movable contact (151).

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