FR2622739A1 - MAGNETIC TRIGGER AND METHOD OF MANUFACTURING - Google Patents

Abstract

A magnetic hold trip device for a low voltage automatic switch, in particular for a differential switch, consists of an iron circuit of generally U-shape 14, a movable pallet 24 with respect to the two cores 17, 18, a holding magnet 29 and a winding 19. These parts are housed in a two-part housing 10 having a horizontal separation seal 13 and which is located near the upper ends of the pole cores 17, 18. The lower part of the housing 11 with the components housed therein 14, 19, 23, 29 is filled with molding resin. Thus, the volume of air trapped in the housing is significantly reduced and components at risk of corrosion are protected by the resin coating. At the same time, these components remain reliably assembled by the resin and can be cleaned after assembly by simple soaking in a suitable bath and / or blowing with compressed air. It is also possible to replace the lower part of the housing 11 with a mold which will be removed after the resin has hardened.

Description

The invention relates to a magnetically held trigger for

  low-voltage automatic switch, in particular for a differential switch, consisting of a generally U-shaped iron circuit, with two polar cores standing on a base, a movable pallet with respect to the two polar cores, a holding magnet cooperating with the iron circuit to create a magnetic retaining flux of the pallet, at least in winding disposed on one of the polar cores and for weakening the flow of maintenance, and a two-part casing housing the elements mentioned above and having a separation joint in a horizontal plane with respect to

two polar nuclei.

  Such magnetic holding releases are known, for example from EP-A-0 154 619 and the filing of

  German patent P 36 40 971.5. In these triggers, the puck

  you can tilt over the frontal surface of one of the polar nuclei

  by means of a pivot made of non-magnetic material, brass

  particular, and rests in the standby position on the surface

  this frontal of the second polar core under the influence of the holding flux and in opposition to the pulling force of one or

  several trigger springs attached to the base plate

  culement. When in the case of triggering, the flow of

  maintenance is weakened by the action of winding

  run by an opposite current, the trigger switches under the

  Z5 fluence of the return spring to the open position, and

  operates through a pusher through and

  smoothing in the upper wall of the casing, the mechanism of

triggering the switch.

  Other forms of construction also referred to

  the invention, operate with applied pallets

  laterally to the polar nuclei and tilting horizontally.

  In addition, the pallet can be predicted linearly moving towards

the top or sideways.

  What is common to all these modes of construction of

  is that the moving parts are located in the upper part of the casing, whose separation seal is in the known triggers more or less close to the

  base of the box, for mounting reasons.

  The assembly of the various parts and their assembly in the

  casing are made using conventional connecting means.

  such as bolts and nuts, rivets, or by

  ge, it being specified that many of these means can be

in parallel.

  It turned out that during the manufacture of such de-

  magnetic latching clutches, two serious disadvantages appear together or separately, namely: - the clogging of the device during manufacture,

  I0 for example by the filings being rectified over-

  polar faces or other particles of material;

  - the vulnerability of the components to corrosion.

  In addition, the assembly and assembly processes in the

  are complex and require a lot of time, but without

  to ensure sufficient security against unintentional loosening

tuit during the service life.

  The object of the invention is therefore to provide a magnetically held trigger whose assembly is simple and which can be conscientiously cleaned without any risk to the users.

  components, before closing the housing, the danger of corrosion

  sion is, on the other hand, seriously diminished.

  According to the invention, the problem has been solved by the fact that the separating gasket is provided near the upper ends of the polar cores, and that the lower part of the housing with the components which are housed therein is

filled with molding resin.

  As an alternative to the second part of the solution, according to the invention, the problem can also be solved by the fact that the separation seal is provided near the upper ends of the polar cores, the lower part of the casing is made of a molded resin block, in which the

  components of the lower part are coated.

  Thanks to the invention, the volume of air trapped in the casing is significantly reduced, and corrosion-resistant components such as most of the circuit of iron and steel.

  the winding, as well as the permanent magnet, are protected against

  to be corrosion thanks to the coating of resin. At the same time these components remain reliably assembled even after a long service life, and can be cleaned properly after

3Z 2622739

  the assembly and the coating of resin, simply by soaking in a

  degreasing bath and / or blowing with compressed air.

  At the same time, the release of the trigger is considered

  considerably simplified by the elimination of the mechanical means

  assembly or special welding or gluing processes, which is

  first embodiment of the invention, the triggering

  The magnetic holding device is provided with a retaining or pivoting plate of non-magnetic material such as the tale of

  [0 brass, serving as support for the pallet and / or tensioning

  reminder spell, since in this case the retention element

  naked or pivoting is secured to the iron core by the

resin filling to be molded.

  According to another advantageous performance characteristic

  Of the invention, the molding resin is of a type which preferably

  The following properties are distinguished by the following properties: - low viscosity during casting, - rapid hardening, - absence of corrosive gases, W0 - no, or at least little heat release during polymerisation,

  - sufficient elasticity after the polymerisation in order to

  avoid mechanical stresses on the embedded parts, in particular during temperature variations, 5 - conservation of the elasticity over the entire range of

service temperatures.

  Molding resins possessing these properties are essen-

  elastomers, polyurethane being particularly

appropriate.

  According to the invention, using a lower portion of resin-filled casing, it is also advantageous for this lower part to be of a plastic whose coefficient of thermal expansion is close to that of the iron cores, so as not to exert strong constraints on it by

  $ 5 through the molding resin.

  Such resins, according to another characteristic of

  the invention can simultaneously serve as impervious

  for sealing the separating joint between the casing parts, since the lower part of the casing has on the separation edge an upwardly open peripheral channel intended to collect during filling the resin in

  excess that overflows, then serving as a seal.

  Another characteristic, concerning an execu-

  Advantageous embodiment of the invention, provides that the connecting conductors of the winding or windings, are led outside by an orifice at the base of the lower casing, sealed by the resin. Therefore, on the one hand we maintain a perfect impermeability of the current and other inputs

  on the other hand, thanks to the coating of resin, it avoids mechanical curvatures

  drivers when they are connected, with

  as a result a possible break.

  An advantageous manufacturing method of such a release is characterized according to the invention by the fact that the iron circuit, the permanent magnet, the electric winding and, if appropriate, the retaining or pivoting plate, are all firstly fixed in the correct position in the lower part of the casing, respectively inside a mold, the resin

  being then poured into the lower part of the box.

  For fixation, an action adhesive is preferably used

  fast, especially cyanoacrylate.

  In combination with the characteristic of indi-

  above that providing a peripheral channel on the separation edge of the lower part of the casing, it is expected that the resin is discharged during filling to a level

  such that it overflows into the channel.

  An exemplary embodiment of the invention will be exposed more

  by means of the annexed drawing, which represents a vertical section

  wedge of a magnetically held trigger designed and realized

according to the invention.

  In the drawing, the shoemaker designated by reference numeral 10 com-

  takes a lower part 11 and an upper part 12,

  which is a separating joint 13.

  A U-shaped iron circuit 14, preferably consisting of

  ferronickel, is placed by its base 15 on projections 16 of the box bottom, and extends upwards by its two

  polar nuclei 17, 18, above the plane of the separating joint

tion.

  The polar core 17 carries a coil 19 with a winding

  of excitation, of which the branch conductors 20

  pour an orifice 21 at the bottom of the lower portion 11 of the drink

  tier. The front surfaces of the two pole cores 17, 18 are located in the same horizontal plane and are ground. On the outer side of the pole core 18 is the appendage 22 of a brass plate 23 having a plurality of folded tabs

  serving as a pivot and restraint, and in the middle

  0 green for the pallet 24; the latter pivots on lan-

  spacecraft 25 arranged on each side of the aperture at an angle to the front surface of the pole core 18. The pallet 24 carries at its upper part a lever arm 26, subjected to the action

  a tension spring 28 extended to an appendix 27 of the flat

  The polar core 18 is divided (not shown)

  and houses between its two parts a permanent magnet 29, which repo-

  is by its lower blade on a median extension 30 of the base 15 of the iron circuit 14, and which by its upper blade is

  0 limited to such a distance from the pallet, that the magnetic flux

  generated by the permanent magnet 29 closes a magnetic circuit

  only in the standby position, the pallet 24 is folded over the other polar surface 17, and it remains there

  maintained with a force greater than that exerted by

  If the excitation winding of the coil 19 is traversed by a current weakening the holding flux, the force of the return spring 28 is predominant, and the pallet 24 rocking under

  the influence of this return spring in the open position

  O0 diqué in the figure, by actuating a pusher 31 sliding in the upper part 12 of the casing, position in which the pusher 31 actuates on its side the cutting mechanism (no

represented) of the switch.

  As shown in the figure, the entire lower part of the casing with the components housed therein, is filled up to the level line 32 of the upper edge of the part

  lower part of the casing 11 of resin to be molded, such as polyurethane

  rethane preferably, which traps all mounted components

  in the lower part of the box after expulsion from the

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  used previously air, and simultaneously closes the orifice 21 serving as a crossing of the drivers of

connection 20.

  Before the resin filling, the iron circuit 14 with the coil 19 is brought to the correct position in the lower part of the casing, and the retaining and pivoting plate 23 is fixed to the polar core 18 by means of an adhesive fast-acting, preferably cyanoacrylate, so that the components

  maintained in good reciprocal positions during the

pleating.

  On the separation edge of the lower part 11 of the stacker is provided a peripheral channel 33 open upwards, in which when filling the lower part

  casing, the resin can overflow, thus forming a joint-

  device, on which the separation edge of

  the upper part of the box when closing the box.

  The lower part of the box is provided with appendages

  in the form of pins 34, which fit into pre-shaped orifices

  seen at the separation edge of the lower part of the casing and which are then riveted. In the case where the box is made of thermoplastic material, which seems judicious, the operation of

  riveting of the appendages 34 can be performed by a brief

  if we. According to the embodiment of the discovery described above, it is clear that it is then possible to replace the lower part of the casing with a suitable mold receiving

  parts and resin so as to obtain after polymerization

  demoulding, a compact assembly adaptable to the

top of the boot.

Claims (12)

  1. Magnetically held trigger for switch   low voltage autoclast, in particular for a different switch   ferential, consisting of an iron circuit of general   U, with two polar nuclei standing on a base, a pa-   Lette mobile relative to the two polar nuclei, a holding magnet cooperating with the iron circuit to create a magnetic flux retaining the pallet, at least one winding disposed on one of the polar nuclei and intended to weaken the flow of maintenance, as well as a two-part shovel housing   0 the above mentioned elements with a separating seal   in a horizontal plane with respect to the two polar nuclei.   res, characterized in that the separating joint (13) is located near the upper ends of the pole cores (17, 18) and the lower part (11) of the casing, including the components housed therein (14, 19, 23, 29) is filled with resin. 2. Magnetically held trigger for switch   automatic low voltage, in particular for   ferential, consisting of an iron circuit of general   o U, with two polar nuclei standing on a base, a pa-   Lette mobile relative to the two polar nuclei, a holding magnet cooperating with the iron circuit to create a magnetic flux retaining the pallet, at least one winding disposed on one of the polar nuclei and intended to weaken the flow of maintenance, as well as a two-part shovel housing   the elements mentioned above with a separating seal   in a horizontal plane with respect to the two polar nuclei.   res, characterized in that the separating joint (13) is located near the upper ends of the pole cores (17, o 18) and the lower part (11) of the casing is formed of a resin block in which the components (14, 19, 23, 29) of the lower part are coated.   3. Magnetically held release according to the claim   1 or 2, with a retaining plate or pivoting non-magnetic material, such as in particular brass t8le,   serving as pivot to the pallet and / or point of attachment of a res-   recall spell, characterized in that the retaining plate or 8 2622739   of pivoting (23) is held fixed to the iron circuit (14) by the resin filling.   4. Magnetically held release according to the claims   1 or 2, characterized in that the filling resin has the following properties: - low viscosity during casting, - fast curing, - absence of corrosive gases, - no, or at least little heat release during the polymerization,   - sufficient elasticity after the polymerisation in order to   avoid mechanical stresses on the embedded parts, in particular during temperature variations, - conservation of the elasticity over the whole range of temperatures.   5. Magnetically held release according to the claim   4, characterized in that the spilled resin is an elastomer mother.   6. Magnetically held release according to the claim   5, characterized in that the spilled resin is polyurethane   Thane. 7. Magnetically held trigger according to one of   claims 1 or 3 to 6, characterized in that the part   lower case is made of plastic material having a coefficient of thermal expansion close to that of magnetic parts.   8. Magnetically held trigger according to the   claim 1 or one of claims 3 to 7, characterized   in that the lower part (11) of the casing has on the separation edge an upwardly open peripheral channel (33) intended to collect during filling the overflowing excess resin, which then serves as a seal. 9. Magnetically held trigger according to the   claim 1 or one of claims 3 to 8, characterized   in that the connecting conductors (20) of the winding or windings are led outside by an orifice (21) at the base of the lower casing (11), rendered sealed by the resin.   10. Method of manufacturing a hold release   magnetic device according to one of the preceding claims,   characterized in that the iron circuit, the permanent magnet, the electric winding and, if appropriate, the retaining or pivoting plate are first fixed in the correct position inside the lower part (11), respectively inside a mold of the casing, the resin then being poured into the lower part (11) of the casing, respectively of the mold.   D 11. Manufacturing process according to claim 10, characterized in that for the fixing is used a fast-acting adhesive.   12. Manufacturing method according to one of the claims   or 11 for producing a magnetically held release according to claim 8, characterized in that during filling of the lower part (11) of the casing, the resin is discharged to a level such that overflows into the channel.