FR2490002A1 - MINIATURE CIRCUIT BREAKER WITH ARC CONTACTS - Google Patents

Abstract

1. Miniature circuit-breaker with a narrow insulating housing (10) comprising connection terminals (16, 18) arranged on the narrow lateral sides of the housing, an operation device (14) located on the front side (12) and a fastening device of the housing located on the rear side (34), said insulating housing comprising separable contacts (20, 22) arranged in an arcing chamber, an arc extinction chamber (30) towards which the arc drawn during the contact separation is guided by arcing horns (46, 48) associated to said contacts (20, 22), a control mechanism (25) for the manual opening and closing of said contacts and an electromagnetic (28) or thermal (26) tripping device for an automatic opening control when a fault occurs, characterized in that the movable contact (42) is constituted by a monoblock piece made principally of copper, comprising two contact surfaces (20, 50) without pellet, a main contact surface (20) and an arcing contact surface (50) inserted between the main contact surface and the arcing horn (48) and that the stationary contact comprises a piece made principally of copper comprising a main contact surface (22), without pellet, and an elastic blade or piece (54, 56, 62) associated with the copper piece, which comprises an arcing contact surface (52), without pellet, and inserted between the main contact surface (22) and the arcing horn (46), the elastic blade or piece (54, 56, 62) being able to make a limited movement to accompany the movable contact (42) during its opening movement, in order to open the arcing contacts (50, 52) after the separation of the main contacts (20, 22).

Description

A 2490002

  MINIATURE CIRCUIT BREAKER WITH ARC CONTACTS.

  The invention relates to a current cut-off device. For a low-voltage electrical installation with low currents, comprising a molded plastic casing housing one or more poles, a pair of separable contact parts for each of the poles and a separation control mechanism

of said contact parts.

  The contacts are delicate points in the electrical equipment and their quality generally determines the reliability and the resistance over time of the device. The heating of the contact parts is directly linked to the contact resistance and in the devices

  low voltage low currents, contacts are almost excluded

high-grade alloy

  silver / silver, especially in low-resistance silver pellets

  sistivity, fixed on copper contact pieces. Pastilles

  are of sufficient thickness to withstand wear by rubbing

  ment during successive maneuvers and they bear without too much damage, in this case without welding or excessive erosion,

  the action of arcs or sparks appearing at the opening. The con-

  tacts with silver pellets are nevertheless of a complex manufacture

  and expensive and their price constitutes a non negligible part of this-

him from the device.

  We have already proposed the abolition of the silver and insurance tablets.

  make contact directly through copper. The devices, in

  The miniature circuit breakers, equipped with such contacts, have

  a correct contact resistance and they resist well to

  pure high intensity currents, but contact welds

  can destroy the device, are frequent.

  It is also known, essentially in medium and high voltage devices, to make the contacts so that the breaking or separation does not take place on the parts ensuring the passage

  continuous current when the device is closed, but these devices

  tifs are complicated and their size and manufacturing cost are opposed to their use in low voltage devices such as

  miniature circuit breakers, small switches or contactors.

  The aim of the present invention is to remedy these drawbacks and to allow the production of a device for breaking low low voltage currents - having contact parts devoid of

  contact pads in silver or silver alloy.

  The apparatus according to the invention is characterized in that one

  of said contact parts has two spatial contact zones -

  separate areas, a main contact area and a contact area

  arcing, that the associated contact piece has a first part cooperating with said main contact area of said one piece. contact to establish primary contacts and

  a second semi-mobile part capable of performing a movement

  limited relative ment and cooperate with said arcing contact zone to form arcing contacts, the assembly being arranged so that in the device's closed position, said main contacts and arcing contacts connected in parallel are both closed and that said relative movement delays the separation of the arcing contacts from the separation of the main contacts during an opening movement, said main contacts being devoid of contact pads and being of a material ensuring good electrical contact, in particular coated with a material

  antioxidant and said arcing contacts being made of a resistant material

  both to the action of an arc or a spark, generated during

  opening or closing the device.

  The semi-mobile part provided on one of the contact parts

  puts the conservation of the opening kinematics of the device and the opening or closing in two phases, the arcing contact carried by the semi-mobile part accompanying in a first stage the associated contact in its running and opening late. It is clear that the only modification of the mechanism of the device, in this case a small lengthening of the stroke

  of mobile contact, does not present any difficulty and that the

  general is easily respected. These changes may

  be made on existing series of devices.

  The semi-mobile part is advantageously constituted by a one-piece elastic blade or attached to the associated contact piece, or a piece resiliently mounted on this contact. It is preferably provided on the fixed contact of the device to cooperate with an arcing contact zone of the movable contact adjacent to the contact zone

  main, but a provision on the mobile contact is designed

  vable without notable complication as it will become clear

  of an example of implementation described below.

  The invention is applicable to any low voltage device using

  silver-plated contact parts, especially at the inter-

  circuit breakers, contactors, circuit breakers, remote switches, that these devices

  They are either single cut or double cut. In the devices

  reils fitted with arc extinguishing chambers, in particular in miniature circuit breakers, electrodes or guide horns

  arc to the extinguishing chamber can be easily changed

  connected to form the arcing contacts without requiring additional parts. A particularly simple embodiment comprises a flexible blade incorporated or integral part of the electrode connecting the fixed contact to the extinguishing chamber, the end of the blade constituting the fixed arcing contact. The flexible blade is advantageously shaped as a blowing loop from the arc to the extinguishing chamber. A hinged or sliding piece

  can obviously replace the elastic blade.

  Contact parts, made of copper or copper alloy or possibly-

  made of aluminum, can wear an antioxidant coating, for example silver or tin in the main contact area to reduce the contact resistance and arcing contacts can

  be made of a tellurium copper alloy or any other resistant material

  both to the action of the arc, for example steel.

  Other advantages and characteristics will emerge more clearly

  of the description which follows of different modes of implementation

  work of the invention, given by way of nonlimiting examples and represented in the appended drawings, in which: FIG. 1 is a schematic view in elevation of a circuit breaker

  miniature according to the invention, shown in the closed position

  mée, the side wall being assumed removed; Figure 2 is a partial view of Figure 1, showing

  the contacts being separated, the main contacts

  blades being open and the arcing contacts still closed; Figure 3 is a view similar to that of Figure 2, showing the contacts in the open position; Figures 4 and 5 are partial views similar to

  that of FIG. 1, illustrating two alternative embodiments

  station; FIG. 6 is a view similar to that of FIG. 1, showing another embodiment of the invention,

  comprising a movable contact carrying a semi-arcing contact

  mobile; Figure 7 is a schematic view of a circuit breaker a

  double break according to the invention, only the parts

tutives being represented.

  The invention is described below in its preferred application to a miniature circuit breaker of the type commercially known as C 32. Figure 1 shows such a miniature circuit breaker and corresponds to Figure 1 of patent application NO 79 25859, filed by

  plaintiff on October 16, 1979, to which reference will be made before-

  carefully for further details on relevant features.

  of this circuit breaker. We recognize in Figure 1 the bot-

  molded tier 10 having on the front face 12 an operating lever 14 and on the two narrow lateral faces of the connection terminals 16, 18. In the case 10 are housed a movable contact 20 and a contact the latter being fixed 22, / connects by a loop conductor 24 at terminal 16. The

  movable contact 20 is controlled by a control mechanism,

  signed by the general reference 25. The bottierlO also contains a thermal trip device formed by a bimetallic strip 26 and an electromagnetic trip device 28 capable of causing in the event of overload

  or short-circuit an automatic opening of the contacts 20, 22.

  In the lower part of the case 10 is disposed a cutting chamber 30 constituted by a stack of sheets 32, which extend parallel to the rear face 34 of the case 10. Fixing claws 36 carried by the rear face 34 cooperate with a DIN rail symmetrical support in a manner well known to specialists The breaking chamber 30 is delimited by end plates or sheets 38, 40 parallel to the rear face 34, the plate 38 being attached to this rear face 34. The movable contact 20 is carried by a contact piece 42, mounted with limited rotation on a pin 43 carried by a contact arm 44, pivotally mounted on a pin 45. When pivoting in the open position of the part

  movable contact 42, the movable contact 20 moves.

  section substantially parallel to that of the sheets 32, the arc drawn between the separate contacts moving along a guide electrode 46 connecting the conductor 24 to the end plate 38 to spread at the entrance to the chamber cutout 30. Such a circuit breaker

  as well as its operation are well known to specialists.

  According to the present invention, the movable contact 20 and the fixed contact 22 are devoid of silver pellets. The contact piece 42 in copper, possibly silver or tinned, comes directly

  in contact with the conductor 24 also made of copper, possibly ar-

  kind or tinned. The silver or tin coating is weak

  thickness and has the sole purpose of opposing the oxidation of the over-

  contact face. The movable contact piece 42 extends beyond the movable contact 20 into a curved horn 48 for guiding the arc towards the breaking chamber 30, this curved horn 48 having movable an arc contact area / 50 susceptible to cooperate with a semi-fixed arcing contact 52. The semi-fixed arcing contact 52 is carried by a

  elastic blade 54, constituted by an extension of the plate of ex-

  end 38. The elastic blade 54 passes through an orifice formed in the electrode 46 and projects from the latter at a point close to the fixed contact 22, interposed between the latter contact 22 and the breaking chamber 30. The elastic blade 54 and the semi-fixed contact

  52 can be made of a copper alloy - tellurium or any other material

  suitable material resistant to the action of an arc. In the closed position.

  ture of the circuit breaker, shown in Figure 1, the pair of contacts 20, 22 and the pair of contacts 50, 52 are both closed, the current borrows u ntanrt almost entirely the path of least resistance, consisting of the contacts 20, 22, forming main contacts. During pivoting of the movable contact piece 42

  clockwise in Figure 1 to the po-

  opening position, the semi-fixed contact 52 accompanies in a pre-

  first phase the moving contact piece 42 in its movement

  thanks to the elasticity of the elastic blade 54 allowing separation

  tion of the main contacts 20, 22 without arc, the current being com-

  transferred to the arc circuit comprising the arcing contacts 50, 52 (fig. 2)

  remained in contact / During continued movement of the connection piece

  movable tact 42, the elastic blade 54 is retained in abutment, so as to cause the separation of the arcing contacts 50, 52 with the formation of an arc. The arc quickly switches to the guide electrode 46

  to go to the breaking chamber 30 in the usual way.

  Similarly, during a pivoting of the movable contact piece 42 in the closed position, the arcing contacts 50, 52 close first, the main contacts 20, 22 being closed after deformation of the elastic blade 54 pushed back by the movable contact piece 42. It is easy to see that the main contacts 20, 22 open and close without an arc and are thereby freed from any risk of welding or erosion due to a closing or opening arc or spark. The main contacts 20, 22 can therefore be made without pads

  of contact. The arcing contacts 50, 52 do not participate in the con-

  duction of the permanent current and can be made of a material chosen for its properties of resistance to the action of the arc. The circuit breaker mechanism can be kept in its entirety, the only modification consisting in a slight increase in the travel of

  pivoting of the movable contact piece 42 corresponding to the

  bending of the elastic blade 54. It is obvious that the elastic blade 54 can be a piece independent of the end plate

  38 in the same material or in a material different from the latter.

  In the example illustrated in FIG. 1, the elastic blade 54 extends behind the electrode 46, forming with the latter

  a closed loop. In the closed position of the circuit breaker, the

  rant goes directly through the main contacts 20, 22, but from

  the separation of these the current coming from the bone 16 p r-

  feeds the conductor 24, the electrode 46, the blade 54, the arcing contacts 50, 52 following a loop path generating a field

  magnetic blowing of the arc drawn during the separation of the con-

  arc tactics 50, 52. As soon as the arc is formed, the latter switches

  on electrode 46 again switching off the loop formed

  killed by the elastic blade 54. This magnetic blowing present during

  of arc formation promotes rapid migration to the cham-

  break break 30. The inventive device takes advantage on the one hand of the presence of an arc horn 48 on the movable contact piece 42 to create

  an arc contact zone, and on the other hand, the presence of the electric

  trode 46 for guiding the arc towards the breaking chamber 30 for

  make a semi-fixed contact 52 acting as an arcing contact. The structure and the arrangement of the arcing contacts according to the invention allow) t the conservation of the size of the circuit breaker. It is obvious that the arcing contact system according to the invention can be applied with the same advantages to miniature circuit breakers of another type or that the arcing contacts can be produced in a different way, some variants being described below by way of examples, with reference to FIGS. 4 to 6, in which the same reference numbers designate analogous or identical parts

to that of figure 1.

  In FIG. 4, the semi-fixed arcing contact 52 is carried by a

  rigid part 56 mounted with pivoting limited by its end 58 op-

  placed on the arcing contact 52 on the plate 38. The rigid part 56 extends in front of the electrode 46 and is biased towards the projection of the electrode 46 in contact with the movable arcing contact 50 by a spring compression 60 bearing on the housing 10. The movement of the part 56 is limited by stops (not shown). A braid 61 connects the rigid part 56 to the conductor 24 to ensure a good electrical connection. We understand that the operation of the circuit breaker according to Figure 4 is described identical to that / with reference to Figures 1 to 3. The material of the

  rigid part 56 may be different from that of the end plate

  mite 38, and the articulation of the end 58 on the plate 38 can

be of any type.

  The rigid part 56 can be arranged as a guide electrode.

  the arc and in this case replace the electrode 46.

  FIG. 5 illustrates another variant, in which the contact

  of semi-fixed arc 52 is carried by an extension 62 of the plate of ex-

  end 38, the extension 62 - plate 38 assembly being mounted

  smoothing parallel to the rear face 34 to bring or

  move the semi-fixed arcing contact 52 away from the movable contact 50. A res-

  fate 64 stresses the extension 62 - plate 38 assembly in the projecting position of the semi-fixed arcing contact 52. The extension 62 can extend into a slot made in the electrode 46, but it is clear that this extension 62 can be arranged as an arc guiding electrode and replace the electrode 46. The braid 61 electrically connects the conductor 24 to the free end of the extension 62 to ensure a good electrical connection. The operation of the circuit breaker

  according to Figure 5 is the same as that described above.

  It can be noted that the semi-fixed or semi-mobile arcing contact part is not necessarily associated with the fixed part of the contact of the circuit breaker, and FIG. 6 illustrates a variant in which the

  movable contact piece 42 carries a semi-movable arcing contact 66.

  on the one hand The conductor 24 has / a main contact area 22, which cooperates with the main movable contact 20 carried by the piece of d '. other than mobile contact 42 and / decaleeen towards the guide electrode 46, an arcing contact zone 68 cooperating with the semi-mobile arcing contact 66. This last semi-mobile contact 66 is carried by a blade ( elastic 70 subject to the movable contact piece 42, so as to urge the semi-movable arcing contact 66 in the direction of the associated fixed contact 68. It is understood that during a pivoting

2490002.

  from the movable contact piece 42 to the open position, the main contacts 20, 22 separate before the arcing contacts 66, 68, the semi-movable arcing contact 68 being driven in rotation after coming into abutment of the end of the movable main contact 20 against the elastic blade 70. The semi-movable arcing contact 66 can obviously be articulated or mounted with limited sliding on the

movable contact piece 42.

  In the above examples, the arcing contacts are offset

  in relation to the main contacts in the direction of chemine-

  arc from arc to breaking chamber 30 to avoid any ac-

  tion of the arc on the main contacts 20, 22. It would not go beyond the scope of the invention to juxtapose or incorporate the arcing contacts in the main contacts, the risk of arcing on the contacts being eliminated by any appropriate means.

  The invention is applicable to other types of circuit breakers or

  breakers, in particular with double break, and FIG. 7 illustrates such an application to a circuit breaker described in the applicant's patent application NO 79 00827 of 11-1-1979. In Figure 7; which corresponds to Figure 1 of the aforementioned patent, it is recognized

  the moving element 72 in the form of a slide capable of being ver-

  rusted in the closed position by an attachment 74. The attachment 74 is controlled by a bimetallic strip 76 or an electromagnetic trip device 78 to release the slide 72 in the event of overload or fault, and to authorize its movement towards an open position. The slide 72 carries a movable contact piece 80 in the form of a contact bridge carrying at its ends movable main contacts 82, 84, capable of cooperating with main fixed contacts 86, 88, constituted by contact zones formed on

  fixed contact parts 90, 92. The displacement in the open position

  verture of the slide 72 causes separation of the contacts 82, 86; 84, 88 by drawing two arches at the entrance of extinguishing chambers

  94, 96. A detailed description of the circuit breaker and its function

  tction is given in the aforementioned patent, which will be advantageously referred to. According to the present invention, there is associated with the movable contact piece 80 an elastic blade 98 extending at its two ends the piece 80 and carrying semi-movable arcing contacts

2490: 002

  , 102 cooperating with arcing contact zones 104, 106 formed on the fixed contact parts 90, 92. The elastic mounting of the semi-mobile contacts 100, 102 is arranged to delay opening

  arcing contacts 100, 104; 102, 106, as described above

  above with reference to Figure 6, and allow opening without arc of the main contacts 82, 86; 84, 88. It can be noted that again the arcing contacts 100, 104; 102, 106 are interposed between the main contacts 82, 86; 84, 88 and the arc extinguishing chambers 94, 96 associated, preventing any migration of the arcs towards Jes

  main contacts 82, 86; 84, 88. The device is particular-

  simple and allows the use of contacts without silver pads. Semi-fixed or semi-mobile arcing contacts can

  be associated with the fixed contact parts 90, 92 in an ana-

  log to that illustrated in FIGS. 1 to 5.

  The embodiments described above clearly show that the invention is in no way limited to a particular type of contact or device. It applies to a circuit breaker, a switch or a contactor with single or double break,

  as well as medium intensity devices with suppressing effect

  sea or only to reduce the amount of money needed to

manufacturing of contacts.

Claims (1)

CLAIMS 1. Current cutting device for a low voltage electrical installation with low currents, comprising a casing (10) in molded plastic material housing one or more poles, a pair of contact parts (42,24, 80, 90, 92) separable for each of the poles and a control mechanism (25) for separating said contact parts, characterized in that one (42; 90, 92) of said contact parts has two contact zones (22, 50; 86, 104; 88, 106) spatially distinct, a main contact area (20; 86, 88) and an arc contact area (50; (29,80) 104, 106), that the associated contact part / has a first part (22; 82, 84) cooperating with said main contact zone (20; 86, 88) of said one contact part to constitute main contacts, and a second semi-mobile part (52; 100,   102) likely to perform limited relative movement and co-   operate with said arc contact zone (50, 104, 106) to con-   set up arcing contacts, the assembly being arranged so that in the device's closed position, said main contacts (20, 22; 82, 86; 84, 88) and arcing contacts (50, 52; 100 , 104; 102, 106) connected in parallel are both closed and that said relative movement delays the separation of the arcing contacts by   compared to the separation of the main contacts during a movement   opening, said main contacts (20, 22; 82, 86; 84, being 88) / devoid of contact pads and being made of a material ensuring good electrical contact, in particular coated with an antioxidant material and said arcing contact (50, 52; 100, 104; 102, 106) being made of a material resistant to the action of an arc or a spark, generated during opening or closing of the device.   2. Apparatus according to claim 1, characterized in that said second part (52; 100, 102) of the associated contact piece (24; 80) is constituted by an elastic blade (54; 98) or a piece (56, 62) pivotally or sliding mounted and resiliently biased towards said one contact part (42; 90,92 3. Apparatus according to claim 1 or 2, characterized in that 1,   said associated contact part (24) is a fixed part, co-   operating with said one movably mounted contact piece (42).   4. Apparatus according to claim 1, 2 or 3, characterized in that said one contact piece (42; 90, 92) is a mo-   copper or copper alloy block with a coating   anti-oxidant in silver, tin or tin-lead alloy   in the main contact area (20; 86, 88).   5. Apparatus according to claim 4, characterized in that la-   said semi-mobile part (52; 100, 102) is made of a copper alloy glassware.   6. Cutting device according to any one of the claims.   tions above, characterized in that it further comprises an arc extinguishing chamber (30; 94,96) and electrodes (46; 104,106) for guiding the arc towards the arc extinguishing chamber ,   said arcing contacts (50.52; 100.104; 102.106) being interchangeable   strips between the main contacts (20.22; 82.86; 84.88), and the   extinguishing chamber on said guide electrodes.   7. Modular step circuit breaker according to claim 6, with bol-   tier (10) flat miniature comprising a fixed contact (22)   bordered by a fixed electrode (46) extending towards the arc extinguishing chamber (30) and a movable contact (42) extended by an arcing horn (48) in the direction of the extinguishing chamber, characterized in that said semi-mobile part (52) is connected -mechanically and electrically to said fixed electrode (46),   so as to constitute an arcing contact (52) adjacent to the con-   fixed main tact (22) and cooperating with said arc horn of the movable contact.   S. Circuit breaker according to claim 7, characterized in that said semi-mobile part (52) is constituted by a tongue   (54) elastic stamped in said fixed electrode (46).   9. Circuit breaker according to claim 7, characterized in that said semi-mobile part (52) is connected to said fixed electrode (46) along a loop path forming a blowing loop   from the arc towards the extinguishing chamber.   O10. Circuit breaker according to claim 6, with flat miniature boot (10) comprising a movable contact (42) cooperating with a fixed contact (22) extended by a fixed electrode (46) for guiding the arc towards the extinguishing chamber, characterized in that said semi-mobile part (66) is fixed as an extension of the mobile contact (42)   to cooperate with an arc contact zone (68) formed on the   said fixed electrode (46) between the main contact area (22)   and the extinguishing chamber (30). (fig. 6).