FR2938370A1 - Electrical switching apparatus i.e. double-interruption electric overload relay, has dual contact bridge provided with cup shaped branch that is matched with shape of cap at level of contact support plate - Google Patents

Abstract

The apparatus (1) has a contact support part (20) e.g. lever, arranged in a swiveling manner, and a dual contact bridge (l11) arranged at a level of the contact support part for establishing an electrically conducting bridge between two fixed contact pieces (101). The contact bridge is provided with a cup shaped branch that is matched with a shape of a cap i.e. cavity, at a level of a contact support plate connected to the contact support part, so that the contact bridge is arranged in a swiveling manner in two planes.

Description

B09-4254EN On behalf of: ABB AG Electrical overload relay with contact bridge Invention of: KOMMERT Richard SCHWEITZER Rüdiger RAULE Corinna Priority of two patent applications filed in Germany on November 12, 2008 under No. 10 2008 057 000.1 and September 26, 2009 under the number 10 2009 043 105.5

The present invention relates to an electrical switching device provided with a pivotally disposed contact support part, at which at least one contact bridge is arranged to establish an electrically conductive bridge between two pairs of fixed contact pieces. The present invention relates in particular to the positioning of a contact bridge in a switching apparatus. Such a switching device may for example be an electrical overload relay. An overload relay is used to protect an electric motor from overcurrent. The known overcurrent relays are provided, at the thermal tripping elements, thermal bimetals heated by overcurrent and ringing in the presence of heat, thereby opening or closing a switching contact point. DE 299 17 173 U1 illustrates an actuating device for an overload relay with a flip-flop at which two contact bridges are spring-loaded for electrically conducting bridging two pairs of fixed contact pieces. The two pairs of stationary contact pieces take the form of a pair consisting of an opening contact and a closing contact.

A generic actuating device for an overload relay is provided, provided with a flip-flop at which two contact bridges are spring-loaded for electrically conducting bridging two pairs of fixed contact pieces, so as to have two points of contact. The latch is held by a snap spring in a first and / or second closed position and can tighten the snap spring by encircling it against the restoring force via a dead position located between the two closed positions. The contact pressure force exerted on one of the contact points is thus applied by the snap spring in that the snap spring pulls up the tilting arm and thus the contact bridge against the contact parts. fixed. The contact bridge and the fixed contact parts must be precisely adjusted to obtain a regular contact force at all contact parts of the contact bridge. In assemblies known hitherto in which a movable contact bridge is provided with two parallel contact pieces, these are either movably disposed in one axis or disposed above an additional spring, for example a spring compression, the spring to obtain several degrees of freedom. It is desired in such a set of contact bridges that a uniform contact force acts on all fixed contact parts of the contact bridge assembly. When the contact bridge is arranged so as to be able to move in an axis, there is a risk that due to differences of measurement and / or variations in the tolerances of the housing of the contact bridge as well as in the position fixed contact parts, the contact force is exerted unevenly on all the fixed contact parts of the set of contact bridges.

When a compression spring is used, the distribution of the contact force can certainly be unified, but this requires an additional component, which is not economically viable. It may further be advantageous for other functional reasons not to position the spring contact bridge, for example to avoid a contact rebound. In the case of snap-switch systems - said opening contacts and closing contacts - the use of a compression spring can have the effect of obtaining variable values for the opening sections at the counter-level. -contact, because of the spring. Constant values are however desired for the opening sections for functional reasons. The object of the present invention is to provide an electrical switching apparatus provided with a contact bridge, in which the simple application of a regular contact force is guaranteed at all contact parts of the contact bridge. . This object is achieved according to the invention by means of an electrical switching apparatus provided with a pivotally arranged contact support part at which at least one contact bridge is arranged for the electrically conductive bridging of two pieces. fixed contact. According to the invention, the contact bridge comprises a cup-shaped appendix at its width side, said appendix being engaged with a cap shape at a contact support plate connected to the support part. contact, so that the contact bridge can be pivotally arranged in two planes. In an advantageous embodiment, the contact support portion comprises a pivotally positioned rocker. In another advantageous embodiment, the contact support portion is a one-arm lever pivotally disposed. An embodiment having as a contact bridge a double-contact bridge with two pairs of opposed contact support arms relative to each other is particularly advantageous. The positioning according to the present invention of the cap-shaped contact bridge at the rocker has the effect that the contact bridge can be moved in all directions when pulled or compressed against the fixed contact parts. It is thus possible to obtain a regular distribution of forces on all the contact parts, and therefore that an identical contact pressure force is exerted on all the contact parts, even when the fixed contact parts of the contact points are not precisely fitted to the contact bridge. All points of contact are therefore homogeneously charged. For snap-switch systems having reversing contacts - said opening contacts and closing contacts - another advantage is that a constant opening section can always be set at the counter contact.

An advantageous embodiment of the present invention is characterized in that the cup shape at the contact bridge is a hollow shape driven into the contact bridge plate, lifting cup-shaped out of the width side of the bridge. of contact. A cap-like heave thus emerges at the contact bridge, much like a panel boss. The bridge can then be arranged in two ways. According to a very advantageous embodiment, the cap shape is a cap-shaped recess made in the contact support plate. The contact bridge is then held in such a way against the contact support plate that the convex bulge of the cup-shaped hollow form of the annex is housed in the cap-shaped recess made in the support plate of the contact.

Another embodiment is characterized in that the cap shape is a cap-shaped uprising formed on the contact support plate. The contact bridge is then held against the contact support plate in such a way that the concavely curved surface of the cup-shaped hollow form of the annex rests on the cap-shaped upright formed on the support plate. contact. An advantageous improvement of the present invention is characterized in that the contact support plate supports two perpendicular guide walls, between which the contact bridge is held. The guide walls can support, in an advantageous improvement, holding noses preventing lifting of the contact bridge from the contact support plate when the contact bridge is aligned in a deformation situation, when the contacts are depressed.

In another advantageous embodiment of the present invention, the contact bridge supports at its longitudinal side the narrower guide means for movably coupling the contact bridge to a guide wall. The guide means made at the contact bridge advantageously complement the holding effect of the holding noses made at the guide walls. The configuration in which the contact support plate is brought against a free end of the rocker is particularly advantageous. The lifting could also be achieved in another way, for example by fixing a cap-shaped portion to the contact bridge, for example by gluing, welding, brazing or their equivalent. Only one type of positioning on the contact support plate would then be possible, in particular that in which the convex crown of the appendix is housed in the cap-shaped recess provided in the contact support plate. Other advantageous configurations and improvements of the present invention are the subject of the subclaims.

The present invention as well as other advantageous configurations and improvements and other advantages of the present invention should be explained and described in more detail with the aid of the drawings of an exemplary embodiment of the present invention, wherein: Figure 1 illustrates a schematic side view of a double interrupt overload relay according to the invention; FIG. 2 illustrates a view in the direction of the sectional plane AA of FIG. 3, thus showing in an enlarged manner the contact support plate and the contact bridge disposed on it; FIG. 3 illustrates an elevation view made on a contact bridge disposed on the contact support plate, the contact bridge being a double-armed bridge; and FIGS. 4 and 6 illustrate views in the direction of the section plane BB of FIG. 3 with different tilted positions of the contact bridge. All identical or equivalent components or groups of components are shown in all figures with the same references.

FIG. 1 illustrates a section of parts coming from an electric overload relay 1, with a housing 2 provided with an inverting key 40 taking the form of a push button which can be depressed and then released again by actuating outside of the case. The reverse key 40 is shown schematically in the form of a cylindrical body provided with an actuating extension 41, the utilization side 42 of the cylindrical body 40 being accessible from the outside of the housing for its actuation. The precise type of positioning of the reversing key, for example its interaction with a return spring and the necessary locking and unlocking mechanisms are not shown here in more detail, since each known configuration can be used here. A flip-flop 20 is further disposed in the casing 2 in the form of a double lever, with a first arm 22 and a second arm 23. A first point of contact 17 is associated with the first arm 22. A second point of contact 12 is associated with the second arm 23. The first point of contact 17 comprises two fixed contacts 151 that can pass conductive manner over two movable contact parts disposed at a movable contact bridge 161 when the contact point is closed. The contact pressure force exerted at the first point of contact is applied by a contact pressure spring 60 which compresses the contact bridge 161 against the fixed contact pieces 151 when the contact point is closed. The adjusting element of the contact pressure spring 60 used is a set screw 701. The second contact point 12 comprises two fixed contacts 101 which can pass in a conductive manner over two movable contact pieces arranged against a bridge. contact 111 mobile when the point of contact is closed. The contact bridges 111, 161 may also take the form of double-contact bridges. A double contact bridge connects two pairs of related contacts, thus four contact pieces in all. A dual contact bridge embodiment is illustrated in Figure 3, see below. The latch 20 is provided somewhat at its center with a bearing extension 21 made approximately perpendicularly to the first arm 22 and disposed with its free end in a bearing housing 201 fixed relative to the housing. A pivot point 202 provided for the rocker 20 is thus formed at the bearing housing, to allow it to pivot in the direction of the arrow P. The rocker 20 is supported with its bearing extension 21 on a cutting bearing comprising the bearing housing 201 and the free end of the bearing extension 21. Other methods and other known bearing devices can of course also be used in so far as they fulfill the same function, in particular a pivoting positioning of the rocker. 20 in the housing 2. A journal 24 is located at the latch 20, approximately centrally between the first and second arms 22, 23, in the connection area of the bearing extension 21. A snap spring 30 is hooked at the level of the journal 24 whose other end is fixed articulated point 31 anchored firmly relative to the housing below the cutting bearing and the bearing housing 201. The junction line i The magician located between the journal 24 and the pivot point 202 is designated by the reference 241. The latch 20 and the associated snap spring 30 together form a snap-switch system. Figure 1 shows the overcurrent relay 1 in the actuated state. The rocker 20 loaded by means of a tension spring via the snap spring 30 is rotated or rotated clockwise in its second stable position or in the second closed position in which the second point contact 12 is closed and the first point of contact 17 is open. From a first closed position in which the rocker is pivoted to the left, thus opening the second contact point 12 and closing the first contact point 17, and not shown here, the transition in the second closed position according to FIG. 1 being triggered by a triggering force A exerted on the thermal trip, if necessary by interconnection of an actuating element and a lever and / or pusher assembly ù not shown here ù on the switching system to click. This can occur so that the actuating element acts on the snap spring and presses it down left clockwise until the neutral position, also called Neutral position is reached and exceeded and the snap spring 30 pulls and closes the latch 20 during the subsequent race in the second stable position. The encircling clamping can also be triggered by causing the actuating member to exert a triggering force on the bearing extension 21. The triggering force is represented in this case in Figure 1 by the arrow A. All assemblies Knocking and thrusting devices known in principle can be used according to the invention and they will therefore not be considered in more detail in the present invention and in the figures. Trigger force A initially pivots latch 20 clockwise until force arrow K of snap spring 30 is aligned with imaginary junction line 241 between trunnion 24 and the pivot point 202. This is the neutral position or dead point of the rocker 20. When the triggering force A is further exerted in this position, in a clockwise direction, the force the snap spring 30 passes to the right of the imaginary junction line 241 so as to further pivot the flip-flop in a clockwise direction and to bring it into its second stable position according to FIG.

In this second stable position, also called the second closed position of the rocker 20, the second point of contact 12 is thus closed and the first point of contact 17 is open, making the whole of the contact gap is obtained at the of the first point of contact 17. The first arm 22 of the rocker 20 compresses to do this the contact bridge l6lverside against the restoring force of the contact pressure spring 60. The contact pressure force exerted at the level the second point of contact 12 is applied by the snap spring 30.

The latter pulls the second arm 23 of the rocker 20 upwards, so that the contact bridge 111 is pulled downwards against the fixed contact parts 101 of the second point of contact 12 and is thus compressed to this point. in law. An operating spring 50 is further installed in the housing 2. This takes the form of a branch spring having a first and a second spring arm 51, 52 and disposed along a fixed axis 53 relative to to the housing and the restoring force acts in the opening direction of the angle formed by the two spring arms 51, 52. The first arm 51 is fixedly supported relative to the housing and the second arm 52 can support resilient with its free end against a stop 25 provided against the second arm 23 of the rocker 20 and load it in the direction of the arrow P with the help of an operating force seeking to tilt the rocker 20 in the direction of the Clockwise.

The snap-button 40 is pressed so that its actuation extension 41 comes close to the second spring arm 52. The second spring arm 52 of the operational spring 50 is blocked by the actuation extension 41 of the key. conversely 40 so that it can no longer press in the second closed position illustrated here of the rocker 20 on the abutment 25. The operational spring is especially important for controlling the return process of the second stable position in the first stable position, as already described in the previously mentioned document E08205. The content of this application must therefore take this into account without further detailing in this application. The restoring forces of the contact pressure spring 60, the snap spring 30 and the release force A are thus harmonized in such a way that the superposition of the release force A and the force K the snap spring 30 is sufficient to keep the first contact point 17 open against the return force of the contact pressure spring 60. The relative value of the restoring force of the contact pressure spring 60 can be adjusted by means of the adjusting screw 701.

The contact bridge 111 of the second contact point 12 is disposed in a cage-like support portion 231 which is connected to the free end of the second rocker arm 23. Figure 2 illustrates the support portion 231 in an enlarged manner. I1 comprises a contact support plate 232 serving as a base and at which two perpendicularly upwardly projecting guiding walls 233, 234 are formed, only one of the walls being visible in FIG. 2, the other being behind and being covered by the visible guide wall 233. The support plate 232 is provided with a recess 235 in the form of a cap open concavely upwards. The contact bridge 111 is cut from a flat sheet metal end and a substantially flat sheet metal part. Figure 3 illustrates an elevational view of the contact bridge 111 in the form of a double-contact bridge. Starting from a central segment 112, a pair of contact arms 113, 114; 115, 116 is formed respectively to the right and to the left and has a slot 117, 118 between the arms, so that each of the contact arms consists of a spring contact arm. On the upper side of each contact arm there is respectively a contact piece 119, 120, 121, 122 thus serving as movable contact parts at the point of contact. Four corresponding stationary contact pieces are also present at the point of contact 12. A cap-shaped appendage 123 is pushed into the sheet at the central segment 112 on the width side of the contact bridge 111. This annex is also called annex 123 cup-shaped. The central segment 112 thus takes a hollow form of panel-like lifting panel-shaped out of the plane formed by the four contact arms. The cap-shaped appendix 123 rises from the side of the contact bridge 111 opposite to the contact pieces. The appendage 123 in the form of a cap is pushed with the other parts during the manufacture of the contact bridge 111 in the form of a cut piece.

The cap-shaped appendage 123 engages with the cap-shaped recess 235, also called cap shape 235, in the support plate 232. The contact bridge 111 thus rests on the contact support plate 232 so that the cap-shaped appendage 123 can roll in two planes with its convex outer surface in the concave inner surface of the cap-shaped recess 235. The contact bridge 111 can thus be pivoted in n '. any direction. FIG. 2 makes it possible to see, through two pivoted positions of the contact bridge 111 represented in dotted lines, the possibility of pivoting in the cutting plane AA, thus around the pivot axis extending in a direction perpendicular to the longitudinal extension of the contact bridge, shown according to FIG. 3. In FIGS. 4 to 6, the possibility of pivoting is represented in the sectional plane BB, thus around a pivot axis coinciding with the direction of the longitudinal extension. of the contact bridge, knowing that Figure 4 shows the horizontal position, Figure 5 the position rotated to the left, Figure 6 the position rotated to the right. Position overlaps are possible in the pivot directions. The possibility of pivoting of the contact bridge due to the positioning of the cap allows the contact pieces 119, 120, 121, 122 arranged on the contact arms to balance the different differences appearing with respect to the fixed contact pieces during the compression of the contact bridge 111 against the fixed contact parts, said deviations being able to occur because of an imprecise positioning of the fixed contact parts or due to manufacturing tolerances imposed during the manufacture of the contact bridge or in operation due to mechanical tensions or mechanical deformations caused by temperature variations. Independently of such inaccuracies, it is thus ensured that the same contact pressure force can be exerted on each contact piece. This is particularly advantageous in a constellation such as that of FIG. 1, since the contact pressure force can be applied to the second contact point 12 due to the tensile force of the directional snap spring 30. around the pivot point 202.

A spring-retaining nose 236, 237 is respectively formed at each guide wall 233, 234, said nose extending into the interior space between the two guide walls. These are used to block the contact bridge, so that it can not leave the contact support plate 232 positioned between the two guide walls 233, 234. The contact bridge 111 further supports at the on its longitudinal side 238 narrow two guide noses 239, 240 facing outwards, also called guide means 239, 240. These are made of sawtooth and are raised between the guide wall 234. They prevent the contact bridge 111 to slide, in the direction of its direction of longitudinal extension, out of the cage-like stop portion 231 formed by the contact support plate 232 and the guide walls 233, 234, see FIG. 3 The cage-type arresting portion may naturally comprise other components, only a few of which are represented here by way of example, these allowing a simple and effective maintenance according to the invention of the contact bridge, so that to be able to adapt simply to s unequal positioning of fixed and moving contact parts, so that the same contact pressure force can be exerted on each contact piece. Accurate precision construction is not necessary. The manufacturing tolerances obtained during the manufacture of the contact bridge and during the positioning of the fixed contact parts in the overload relay housing can be increased without the contacts losing their reliability. This allows for inexpensive manufacturing. The delay caused by changes in mechanical stress or temperature of the overload relay no longer leads to loss of contact force. In one embodiment shown here, the flip-flop can be manufactured in one piece with the cage-like stop portion and the bearing extension 21 in the form of an injection molded portion from synthetic material.

Other groups of components required for an overcurrent relay, such as, for example, terminals for connection to the mains and auxiliary power supplies, the bimetals themselves or push-fit assemblies supporting the movement of the bimetals on the rocker, are not shown in the figures, since they can be the subject of other inventions or do not differ from the assemblies known in the art.

List of references

1 overload relay, switching device 2 housing 12 second contact point, closing contact 17 first contact point, opening contact 20 contact support part, flip-flop 21 bearing extension 22 first arm 23 second arm 24 pin 25 stop 30 snap spring 31 pivot point 40 reverse key 41 actuation extension 42 operating side 50 operating spring 51 first spring arm 52 second spring arm 53 fixed shaft relative to the housing 60 contact pressure spring 101 fixed contact, closing contact 111 movable closing contact, contact bridge 112 central segment 113 114 115 116 117 118 119 120 121 contact arm contact arm contact arm contact arm slot slot contact piece contact piece contact piece 122 contact piece 123 cap-shaped appendix 151 fixed contact, opening contact 161 movable opening contact, contact bridge 201 bearing housing 202 Pointer t pivoting 231 cage-type support part 232 contact support plate 233 guide wall 234 guide wall 235 cap-shaped recess 236 retaining nose 237 retaining nose 238 narrow longitudinal side 239 guiding means, guide nose 240 guide means, guide nose 241 connecting line 701 adjustment screw P arrow K force arrow E adjustment direction A release force

Claims (11)

REVENDICATIONS1. Electrical switchgear (1) with a pivotally arranged contact support part (20) at which at least one contact bridge (111) is arranged for the electrically conductive bridging of two fixed contact pieces ( 101), characterized in that the contact bridge (111) has a cup-shaped appendage (123) at its width side, said appendix being engaged with a cap shape (235) at a a contact support plate (232) connected to the contact support portion (20), so that the contact bridge (111) can be pivotally arranged in two planes. Electrical switching apparatus according to claim 1, characterized in that the contact support portion (20) is a pivotally arranged rocker. Electrical switching apparatus according to claim 1, characterized in that the contact support portion is a one-arm lever pivotally disposed. Electrical switching apparatus according to claim 1, characterized in that the contact bridge (111) is a double-contact bridge provided with two pairs of opposing contact support arms (113, 114; 115, 116). one compared to the other. An electrical switchgear according to claim 1, characterized in that the cup-shaped annex (123) disposed at the contact bridge (111) is a cup-shaped hollow shape rising off the width side. in the contact bridge plate driven out. An electrical switchgear according to claim 1, characterized in that the cap shape (235) is a cap-shaped recess formed in the contact support plate (232). Electrical switching apparatus according to claim 1, characterized in that the cap-like shape is a cap-shaped lifting formed on the contact support plate. Electrical switchgear according to claim 1, characterized in that the contact support plate (232) supports two guide walls (233, 234) protruding perpendicular to them and between which the contact bridge (111) is maintained. . 9. Electrical switching apparatus according to claim 8, characterized in that the guide walls (233, 234) support holding noses (236, 237) for preventing the contact bridge (111) from being lifted out of the contact support plate (232). Electric switchgear according to claim 8, characterized in that the contact bridge (111) supports at its narrow longitudinal side guide means (239, 249) for movably coupling the contact bridge ( 111) to a guide wall. An electrical switchgear according to claim 1, characterized in that the contact support plate (232) is disposed on a free end of the contact support portion (20).