WO1990015709A1

WO1990015709A1 - Process and equipment for embedding the inside of an electric apparatus in resin, such as a proximity detector, the related electric apparatus and containers for said apparatus

Info

Publication number: WO1990015709A1
Application number: PCT/FR1990/000446
Authority: WO
Inventors: Gilles Grenet; Catherine Ullmann
Original assignee: Telemecanique
Priority date: 1989-06-21
Filing date: 1990-06-20
Publication date: 1990-12-27
Also published as: FR2648745A1; GB2241465A; JPH04500432A; FR2648745B1; IT1242121B; GB9102336D0; IT9048081A0; IT9048081A1

Abstract

The proximity detector includes a probe (4) and a printed circuit (3), contained within a case (33) which is closed by a lower cap. A plug (35) with connection pins (36) running through it, closes off the other end of the case. Said plug (35) also includes a filling funnel (13) allowing through a resin which can be hardened and which is able to enter once the container has undergone centrifugation. Said resin forces the air out through interstices (i3) which the resin itself cannot penetrate. During this operation, the funnel is held sealed between elastomer parts belonging to two centrifuging rotor elements which define a recess for the apparatus. Application: faster and more efficient filling.

Description

"Method and installation for drowning in resin the interior of an electrical device such as proximity detector, related electrical device and containers therefor"

The invention relates to an electrical appliance comprising a receptacle capable of receiving electrical components, in particular those intended for constituting a proximity detector in which a sensitive probe is arranged at one end of this receptacle, while an opposite end is intended to receive insulated conductive electrical connection means for its power supply and for the transmission of output signals, said components being embedded inside the container, in a hardened resin establishing an isolated immobilization of the components and mechanical adhesion with the inner walls of the container.

The invention also relates to containers for such an apparatus, a method for drowning in resin the components of such an apparatus, and an installation for carrying out this method.

It is known that the operation of injecting hardenable material to which these devices are subjected aims to give them perfect reliability, resulting from an insensitivity to shocks or vibrations, from galvanic isolation of the components, and from a total protection against fluid or atmospheric agents of the environment. The methods of filling the receptacles of these devices with hardenable resins have previously used, to expel air, either with the effect of natural gravity or with a entrainment effect obtained by an injection of resin under pressure; if necessary, a vacuum degassing operation has even been implemented.

These processes, which have given usable results, however had drawbacks insofar as their implementation required relatively long manufacturing times and / or complicated installations; particular configurations of the containers and / or of the components which they received sometimes even left residual bubbles or did not prevent the appearance of shrinkage which during a phase of withdrawal of the resin risked subjecting them to excessive stresses . Furthermore, the very choice of these resins was difficult taking into account the properties required, sometimes contradictory: fluidity, viscosity, adhesion, insulating power and hardening time.

The invention therefore aims to satisfy simultaneously and better than in the past the requirements of quality and reliability regarding the products obtained, and the objectives of simplicity of manufacture and brevity of the filling operation.

Within the framework of the implementation of the process, the invention is also interested both in the particular conformation that it is necessary to impart to the products so that the process can be carried out in a safe, simple and effective manner, that to an installation or apparatus which is itself economically adapted to the product to be processed and to the requirements for reducing the technical cost of mass production.

According to a first aspect of the invention, the electrical apparatus is characterized in that the orifice is an orifice for introducing the resin under the effect of a force field much greater than gravity, intersections being provided and dimensioned between parts of the container respectively of the apparatus so as to allow on the one hand the escape of air through them when the resin penetrates therein, and on the other hand to prevent the resin from s escape to the atmosphere under the effect of these forces.

According to a second aspect of the invention, the container for such an electrical appliance comprising a plug crossed by electrical conductors is characterized in that the plug has a filling chimney having internally the orifice communicating with the internal volume of the container and externally having a sealing surface with a means for introducing resin, this chimney extending externally to the cap.

According to a third aspect of the invention, the container for an apparatus according to the first aspect is characterized in that it comprises a case and a removable part simultaneously surrounding the case and the cable during the circulation of the resin, this part comprising a resin supply orifice, the interstices being formed between the cable and the removable part. According to a fourth aspect of the invention, the method for embedding in resin the components of an electrical appliance located in a container of this electrical appliance is characterized in that:

- a - the container is fixed in the eccentric position on a centrifuge rotor and a container filling orifice is tightly connected with a supply channel which extends to a central area of the rotor;

b) a predetermined quantity of resin in the fluid state is introduced into the central zone and the rotor is rotated to pass this resin by centrifugation from the central zone towards the interior of the container, allowing the air to escape from the container, and the rotation is maintained substantially until the resin has firmed up.

According to a fifth aspect of the invention, the installation for implementing this process is characterized in that it comprises:

- two mobile rotor elements between a loading and unloading position in which they are spaced from each other and a filling position - centrifugation in which they define at least one eccentric retaining housing for a container for an apparatus for filling with foam, a central cavity and a resin supply channel by centrifugation from the cavity to a filling orifice of the container ;

- clamping means for pressing the two rotor elements against one another so as to seal the resin between said elements and with a sealing surface provided on the container around the orifice;

- Means for introducing measured quantities of resin into the central cavity;

- Means for rotating the rotor elements together. Other features and advantages of the invention will emerge from the description below relating to non-limiting examples. In the accompanying drawings:

- Figures 1, 3 and 4 are sectional views of three types of electrical devices according to the invention, before filling with resin, devices whose container is permanently associated with a connection cable;

- Figure la is a view similar to Figure 1, but after filling with the resin and leveling the chimney;

- Figure 2 is a sectional view of an electrical device according to the invention in which the connection is made using a fixed base and a removable connector;

- Figure 5 is a simplified perspective view of organs used for the application of the method according to the invention to devices such as those of Figures 1 to 4; - Figure 6 is a simplified perspective view of an installation for the implementation of process ;

- Figures 7 to 9 are partial axial half-sections of three embodiments of the centrifugation rotor shown atically dried in Figure 6, in the filling and centrifugation position;

- Fig 10 is a simplified partial top view of an installation equipped with a turntable carrying several rotor plates;

- Figure 11 is a simplified top view of a table according to Figure 10 in which individual movable sleepers are associated with each pair of rotor elements to effect their bringing together and their separation;

- Figure 12 is a simplified top view of a turntable using only one motor means with vertical action to operate the approximation and separation of the rotor elements;

- Figure 13 is a partial view of a composite turntable sector usable for filling containers having an integral connection cable;

- Figures 14 and 15 are partial views of other embodiments of such a tray;

- Figure 16 is a top view of another embodiment of the turntable; and

- Figure 17 shows two partial sectional views of the previous plate, by the planes LL 'and MM'.

Electrical devices concerned by the invention and which will be illustrated here in a nonlimiting manner by inductive proximity detectors are shown in FIGS. 1, 2, 3 and 4.

A first type of detector 1 visible in FIG. 1 in the state preceding the introduction of the resin comprises a cylindrical case 2, an electronic device 3 which consists of a prior assembly of a wound probe 4 with a circuit board prints 5 bearing components 6; this assembly is here carried out using a suitable resin mass 7 which also establishes a mechanical connection of the preceding elements 4, 5 with a cup 8 with skirt 9. The cup 8 receives the probe 4 and at the same time constitutes by its front wall a closure cap for one end 10 of the case.

A plug 11 placed at an opposite end 2a and here also taking the general form of a cup, has an internal skirt 12 fitted into the end 2a of the case and an external chimney 13. The chimney 13 has an orifice 14 at the entry of a channel 25 passing through the plug. An external annular surface 15 of the chimney 13 is adjacent to the orifice. The plug 11 also comprises a substantially central opening 16 allowing the adjusted passage of a sheath 17 belonging to an electric cable 18. The chimney 13 has at its base a weakening of section, or a primer of rupture 26.

This electric cable contains insulated conductors 19, 20, 21, the stripped ends of which are electrically connected to appropriate points of the device 3 in the container constituted by the case 2, the cup 8 and the plug 11.

The skirt of the plug and that of the cup are adjusted with the internal cylindrical surface of the case so that when these are put in place, an empty internal volume 22 is limited between these various parts.

The filling chimney 13, the diameter of which is relatively small, is intended to allow passage to a mass of curable resin 22 '(FIG. 1 a) which is introduced through the orifice 14 and the channel 25 to flow into the internal volume. 22 and completely occupy it, while expelling the air through interstices it, i2, formed in the upper region, for example between the case 2 and the skirt 12 and / or between the opening 16 and the sheath 17 These interstices are sufficient to allow the passage of air, but are too thin to allow the passage of the resin, given the viscosity of the latter.

A second type of detector 31 visible in FIG. 2 presents a constitution similar to the previous one, except with regard to the end 32 of the case 33 opposite the probe 4. This end 32 has a neck 34 in which is engaged a plug 35, the part directed towards the outside comprises through conductive pins such as 36 mutually insulated to form a base 37 capable of receiving a removable connector and not shown.

As in the previous example, the plug has a chimney 13 with a through channel 25 extending outwards from its weakened base 26 while a gap i3 is formed between the internal surface 40 of the neck and the plug 35.

A third type of detector 41 represented in FIG. 3 has an internal constitution which recalls that of the previous two. However, given the diameter - d - presented by the case 42, barely greater than the diameter - b - of the sheath 18 of the cable, it was not possible or appropriate to interpose a plug between the case and the cable for the upper closure of the case and the longitudinal guide of this cable. For the establishment of the resin, a removable end piece 45, is fitted on the cable 18 and on the end 44 of the case adjacent to the cable. which has a filling orifice 45a through which the resin will be introduced into the case 42 via the annular gap 46 between the cable 18 and the interior surface of the cylindrical case.

The filling resin 22 ′ can either extend over a certain height - h - in the end piece 45 beyond the end 44 of the case, or else stop substantially at the end 44 of the case opposite to that receiving the probe. After the resin has hardened, the end piece 45 (on which the resin does not adhere) is removed by sliding it along the cable. The interstices through which air can escape during the penetration of the resin do not appear on the finished detector: they consist of a small clearance i4 existing between the sheath of the cable 18 and an orifice 45b of the end piece 45, orifice which is crossed by the cable 18 and positions the latter during filling. Thus, in this embodiment, the end 44 has, during the manufacture of the detector, a chimney role, the inlet opening for the resin of which is constituted by the annular gap 46 comprised between the opening 47 of the case opposite the probe and the sheath of the cable 18. The outer surface 49 of the case constitutes, near the end 44 of the latter, a fitting and sealing surface for the end piece 45.

In a fourth type of detector 51 visible in FIG. 4, the case 52 has an internal diameter so small that the sheath of the cable 18 can only penetrate there by leaving only a narrow gap i5 which constitutes the gap exhaust air during filling. The resin inlet orifice is a hole 56 passing through the case in a region as close as possible to the end 57 of the sheath. This orifice is surrounded by a surface 58 of the external side wall of the case 52 which will be used to prevent leakage of resin when the latter is directed towards the internal volume of the case.

For all the types of detectors shown, centrifugal force is used to bring a mass of liquid resin, the fluidity, viscosity and adhesion with the walls of the case and / or with those of the electronic device are not negligible.

The use of a force field much more intense than that of gravity has proved extremely advantageous to operate not only a flushing and rapid filling of the volume, but also for favor the evacuation of residual air bubbles which could otherwise nestle around certain components; perfect adhesion is also acquired between the mass of resin 22 ′ occupying the volume 22 on the one hand, the internal wall of the case, the previously assembled sub-assembly 3, the sheath of the cable, and the plug (when that -this is present) on the other hand.

A field of centrifugal forces of the order of 400 g (4,000 m / s ² , g representing the acceleration of gravity) has proved sufficient to efficiently, completely and quickly fill cases of several sizes, with resins essentially chosen for their reduced hardening time, while the previous methods required resins with low viscosity to be preferred.

Preferred according to the invention a resin, or optionally composite material, simultaneously having good qualities of electrical insulation, low viscosity, high fluidity, reduced curing time at room temperature, low cost and volume contraction weak during the curing phase, and good adhesion properties with the plastic or metallic material of the case, or of the comparable container if it is a device other than that described by way of example.

In all cases, the dimensions to be given to the air exhaust interstices il to i5 require special attention: these must be determined so that under the effect of the force field the resin chosen cannot escape through them, while the air will have to escape from it as quickly as possible by the same path. At the same time, an excellent seal, at least with respect to the resin, must be established on the surface surrounding the orifice for introducing the resin or immediately adjacent to it to avoid local leakage of the resin. The implementation of the method of filling by centrifugation comprises the following steps, with reference to FIG. 5 briefly representing an installation for simultaneously filling two detectors 59 ′ and 59 ": - a - detectors 59 * and 59" empty of resin in suitable housings, located in the vicinity of the periphery of a rotor 60 of vertical axis, so that the longitudinal axis of each detector container is substantially in the plane of rotation and that the chimney 13 of the detector 59 ' and the application surfaces 58 of the detector 59 "are placed in contact with a supply channel 63 'respectively 63"; the housings and channels 63 ', 63 "are formed between a plate 64 and a cover 65 of elastically deformable material which make up the rotor and are separable; the channels extend to the housings from a central area 66; the region of each detector adjacent to the filling orifice and to the degassing interstices it,... i5 is close to the axis YY ′ of rotation of the rotor relative to the rest of the detector;

- b - pressure forces are applied to clamp axially ent one against the other the plate 64 and the cover 65 so that the channels 63 "and 63" seal the external surface of the chimney 13 respectively the surfaces application 58;

- c - a motor torque - K - is applied to the rotor 60 to communicate to the latter a rotational movement around its axis YY 'distinct from the axes of the detectors 59' and 59 "; - d - a quantity - Q - of still fluid curable resin is introduced into the central zone 66 so that this quantity moves towards the periphery of the rotor under the effect of the centrifugal force which is communicated to it by its contact with the rotor 60, this resin having a hardening time greater than the time interval required for the rotor to reach its speed of substantially uniform nominal rotation;

- e - the supply of resin is interrupted when the quantity introduced - Q - is greater than the free internal volume 22 of the containers 59 'and 59 "and less than the total volume comprising said internal volume increased by the volume of the channels 63' and 63" and that of the central zone 66; in the case shown where more than one container 59 ′, 59 ″ is filled at the same time, the quantity Q is even greater than the sum of the internal volumes 22 and the volumes of the channels 63 ′ and 63 ″, so that it a certain amount of resin remains in the central zone 66 even after filling all the detectors 59 and channels 63; during centrifugation, the material located in the central zone, which is of revolution around the axis YY ', tends to form a ring of uniform thickness under the effect of centrifugation, ring which certainly supplies the detectors until completely filled; in other words, with respect to the centrifugal force field, the various containers 59 ′, 59 ″ and channels 63 ′, 63 ″ are arranged so as to undergo a so-called “source” supply;

- f - the rotational movement is maintained, taking into account the local temperature, for a time interval δt sufficient for on the one hand the resin to be able to completely fill the internal volume of each detector 59 *, 59 "by driving out the air through the interstices it to i5 of the detectors and the interstices between plate 64 and cover 65 and that on the other hand this resin has reached an appropriate degree of hardening; - g - the rotational movement of the rotor 60 is interrupted by exerting a braking torque - J - to the rotor 60 or to a drive means 72 having developed the engine torque;

- h - the tray 64 and the cover 65 are separated axially from one another to give access to the containers 59, 59 "and to a core of resinous material 73 which occupied the channels 63 ′, 63 ″ and which became integral with the containers during hardening, the rotor 60 being made of a material to which the resin used does not adhere; - i - the carrot 73 is broken flush with the chimney 13 (point of weakness 26) and surfaces 58 before or after the previous operation This core can even be sheared by appropriate means during the deceleration of the rotor by using the kinetic energy of the rotor as energy.

The duration of the different stages can vary, in particular as a function of the speed of rotation chosen, the dimensions of the rotor 60, the nature of the resin, the size and content of the containers 59 ′, 59 ″ as well as the temperature.

As an indication, we can give the following examples of parameters for a medium-sized container:

. rotor rotation speed: 25- revolutions / second

. centrifugal force of the resin, per unit mass: 4,400 m / s ²

. filling time: 20 seconds δt: 4 minutes The resin used preferably belongs to the family of polyurethanes. It does not include a blowing agent such as freon. Before introduction into the central zone 66, the components of the resin 4 (polyoi and polyisocyanate) are mixed at a temperature of about 40 ° C to form a semi-liquid mass and a very fine inorganic filler is added to it, such as calcium carbonate, the mixture having for example a viscosity of approximately 1500 centipoises and being able to solidify in approximately 5 minutes. The temperature prevailing in the container at the time of hardening in order to promote the latter and shorten the cycle time, can be increased by preheating and / or heating the containers 59 ′, 59 ″ and / or the rotor 60.

It is purely by way of illustration that two detectors 59 ′ and 59 ″ of different types have been shown in the same rotor. In practice, the same rotor 60 generally comprises several identical housings and channels intended for identical detectors.

A semi-automatic installation 80 visible in FIG. 6, usable for implementing the method which has just been described comprises a frame 81 in which is disposed the rotary electric motor 72 whose axis of rotation W ′ is preferably vertical . Coupling means 83 extend the drive shaft to the external receiver turntable 64 which is pivoted on the frame and whose axis of rotation YY * is advantageously parallel to, or coincides with, that of the engine. For obvious reasons of balancing, this plate is preferably circular.

In its simplest form, for example that which will be the most economically suitable for the manufacture of a product such as that of FIG. 2, this plate is made of a deformable material having however a certain firmness. This can be achieved in a silicone resin because after polymerization, the ^'material shows no substantial adhesion with curable resins. On the upper surface 84 of the tray 64 are formed cavities or cavities 85 (only one is shown) to receive, and at least partially maintain, a container such as 59 to be filled with resin, between the central zone 66 of the tray and this cavity , circulates all or part of the substantially radial channel 63. The upper face 84 of the plate 64 has an indexing notch 88.

Opposite the plate 64 is the cover 65 of substantially similar dimensions, which is pivoted along the axis YY 'by means of a hollow shaft 91 in a cross member 92 which connects the ends of the rods 96 and 97 of two jacks 98 and 99 by means of which said cross member is movable parallel to the axis YY ′ in direction F or G, in order to distance and respectively bring the cover 65 closer to the plate 64.

The cover 65 which is made at least on the side directed towards the plate 64 in the same material as the latter, and which will be applied to it, has the function of either completing the shape of the first cavity 85 thanks to a second complementary cavity 93 (Figure 7), or simply to close the cavity 85 to maintain, in service, the container to be filled (Figure 8). In combination with the channel or the part of the channel 63 carried by the plate 64, the cover 65 can also either have a complement 88 to the first (FIG. 7) or simply operate the closing of the latter (FIG. 8).

The cover 65 further comprises a second central zone constituted here by an opening 89 which allows the resin to access the first central zone 66 in the H direction. A finger 94 placed on the face 95 by which the cover 65 is in contact with the plate 64 engages in the notch 88 of the plate 64 when this contact is made, to give the plate 64 and the cover 65 a precise relative angular position. Once joined by the jacks 98, 99, the plate 64 and the cover 65 form a whole comprising the means for fixing the devices 59 and the means for supplying the resin, and constitute in a way a mold by which one can simultaneously fill and overmold resin in and on a device of particular shape and function. Coaxial with the hollow shaft 91 aligned with the opening 89 is a pouring spout 101 which is connected to a liquid resin reservoir 102 via a channel 103 passing through a metering valve or other measured delivery means 104.

When the resin is formed by the combination of several components, corresponding material reservoirs and not shown as well as a proportional mixing device are associated or integrated into the reservoir acting as a buffer.

The members 101 to 104 are carried by a bracket 105 to which is fixed an electronic control automaton such as 106. This has the function of delivering to the valve, to the motor, to the jacks and to the brakes orders of operation and of '' stop taking into account alert signals which can come for example from push buttons such as 106, 107 - which inhibit certain actuators (such as cylinders 98 and 99 in the direction of descent) when the operator has not both hands applied to these buttons -, or be emitted by position switches signaling the arrival of the crosshead in each of its extreme positions, or be developed by probes measuring physical parameters such as rotation speed, time intervals , or temperature if applicable.

Warning devices such as 108, 109, 110 can advantageously signal the operator by optical or audible progress of operations, or the presence of faults.

According to an embodiment 120 (FIG. 10) which is particularly advantageous since it makes it possible to increase the production rates, at least three turntables 121, 122, 123 are arranged on a pivoting table 124 having the ability to successively take several angular positions . At each of the angular positions I, II and III obtained by rotations in the direction R are executed one or more of the phases of the manufacturing process defined above. For example, we can split a complete manufacturing cycle into a succession of three stages:

- In position I of the table, a tray 121 is stopped and the corresponding cross member is raised to give access to the cavities in which an operator placed opposite (or if necessary a feeding robot) arranges the containers in the cavities;

- At the same time, the plate 122, which was loaded previously when it was facing the operator and whose cross member has been lowered, is located opposite the pouring spout which delivers a measured amount of resin to it;

- At the same time, the plate 123 which was previously supplied with resin is in rotation to operate the centrifugation of the resin and give it the ability to polymerize.

When the longest phase is carried out to its end, for example the centrifugation phase, and the corresponding plate 123 is stopped or in the course of immobilization, the table operates a rotation which brings the latter opposite 1 ′ operator to be unloaded as soon as the corresponding cross member is raised. According to an economical embodiment, the energy of rotation of the plates can be recovered to rotate the table from one point to another, which, at the same time, provides the braking necessary for these plates.

A direct application of the provisions of FIG. 6 to this embodiment 120 results in having three sets of movable crossmembers 125, 126, 127 comparable to that shown in 92 on a rotary table 124 and therefore using six jacks or the like, see figure. 11. The embodiment 128 visible in Figure 12 allows to reduce to a single, 129, the number of cylinders. The jack 129 is placed at equal distance between the posts II and III parallel to the axis of the rotary table 124. The movable rod of this jack carries at its end two brackets or branches 131, 132 each carrying under them a cover 133, 134 similar to the cover 65. There are therefore only two covers 133 and 134 and when a lower turntable 135 carried by the table 124 arrives in position I, it has no cover and is already accessible for discharging them. full containers and load new empty containers. In positions II and III, the jack 129 maintains the two covers in the low position during filling and respectively centrifugation. The cover 134 is locked on the tray located in position II and is released from the arm 132. In position III, it is the opposite, the cover 133 is released from its tray and mates with the arm 131. Thus, when the jack 129 raises the arms 131 and 132, only the cover 133 is raised, the cover 134 remaining in place to contain the resin. The table 124 rotates and the cover 134 passes to position III. At the same time, the arms 131 and 132 make a U-turn according to arrow Z, which brings the cover 133 back to position II. The arms 131 and 132 descend and the cycle begins again.

According to an advantageous embodiment, one and the same rotary drive motor can be coupled by means of belts to each of the three plates, and by means of couplings (preferably electromagnetic) whose excitation is operated. in good time by the controller.

Hitherto, installations oriented towards the manufacture of products have been shown, such as that of FIG. 2, not comprising a permanent connection cable such as 18 in FIGS. 1, 3 and 4. When the receptacles of one of these last three types are to be filled by centrifugation, it is necessary to have rotors capable of accommodating the corresponding cables during this phase.

One can then use an arrangement 150, such as that visible in FIG. 13, where a composite turntable 151 comprises a circular metallic support 152 and a disc of deformable material 153 of smaller diameter.

On the periphery of the support 152 are arranged on the one hand housings such as 154 in which the receptacles 59 will be housed, and on the other hand receiving pockets 156 placed between the housings to receive the cable 18 having been previously wound up.

In this arrangement the radial channel 63 receiving the chimney 13 of the container 59 is formed at least partially in the disc 153 and the chimney 13 is pinched in a sealed manner during the approaching and the application of an upper cover (which does not not shown in the figure) on disc 153.

Between two neighboring channels 63, 163 is a groove, corridor or curved passage 161 to allow the end 162 of the cable 18, adjacent to the container, to flow to an adjacent pocket 156.

This arrangement which is advantageous when the containers are large can be subject to variants 170, 180 visible in Figures 14 and 15, when it is proposed to fill small containers.

In the first variant 170, see FIG. 14, where a container 59 is filled by its lateral orifice 56, the plate of elastic material 173 has a supply channel 174 a cavity 175 for receiving and holding the case in a sealed manner as well as '' a passage 176 ending in a pocket 177 of a metal support turning 178. For this purpose the plate 173 may advantageously have a notch 179 around the pocket, which incidentally provides a saving of elastomeric material. In order to have more cases 59 on the same turntable 182, see FIG. 5, it is also possible not to have the pockets 183 between the cavities, but as far as possible in the radial extension of these; we chose not to arrange the containers 59 radially, but in an inclined orientation which will nevertheless allow air to escape through the existing gaps between the cable 18 and the case and through a residual gap that l air escaping under pressure can itself create between the two deformable rotor elements such as 185. As previously, the cable 18 is guided in a curved passage 186 whose shape is better adapted when the container 59 is inclined relative to the radial direction as just said. In all of these installations, the tightening of the opposite elastomer-plate-cover pairs is used essentially to provide the seal which allows the resin to collect in the central part 66, to be distributed in the channels 63, and to enter the containers 59 without any leaks; the drive of the upper cover by the lower plate is advantageously ensured by the cooperation of fingers and notches.

According to an interesting arrangement 190, visible in FIG. 9, a longitudinal clamping of the container 59, clamping intended to resist the centrifugal forces undergone by the container 59, to avoid for example the dislocation of the cup 8 of FIG. 1, is obtained by to a pusher 195 which pushes the container 59 radially inwards and which for this purpose is actuated by a counterweight 191, by means of a reversing lever 197 articulated to the metal support 152 of FIG. 13. When the support 152 is in rotation, the counterweight is subjected to centrifugal force, transformed by the lever 197 into a force exerted radially inwards on the container 59 .

As shown in FIGS. 16 and 17, the plates and the centrifuge covers 200 can comprise a composite metal support 201 having clearances 202 in which only thin layers 203 of elastomeric material are arranged to form the channels 205 and the central zone 206, the cavities 204 can be directly formed in the support.

The method defined above, as well as an apparatus intended for its implementation, have been specified within the framework of an application to proximity detector devices, one form of current use of which comprises a probe of circular shape which is practically fitted into an open end of a cylindrical container.

It will be noted that the fact of making a probe a local modification of its shape to allow a resin inlet orifice to be placed in its vicinity in order to allow the circulation of the resin naturally makes it enter the latter. the framework of the devices protected by the invention; the same applies if it is decided to provide air exhaust interstices in the regions which would then become more favorable than those mentioned previously, by operating, if necessary, another orientation of the containers.

If, for the filling of certain containers, it appeared that the components occupying them were not able to withstand excessive acceleration, the penetration and displacement of the resin could be helped by applying a vacuum to the external vicinity of the interstices; this depression could itself come from a source of vacuum or be developed by fins or the like being carried by one of the many rotating members which in this case would only last for the time of rotation.

Claims

1. An electrical appliance comprising a container (2, 8, 11; 33, 35; 42; 52) capable of receiving electrical components (5, 6), in particular those intended for constituting a proximity detector in which a sensitive probe (4) is arranged at one end of this container, while an opposite end is intended to receive insulated electrically connecting means (18, 36) for its supply and for the transmission of output signals, said components being embedded inside the container, in a hardened resin establishing an isolated immobilization of the components and mechanical adhesion with the internal walls of the container, the container having an orifice (25; 46; 56) for the introduction of the resin during the manufacture of the apparatus, characterized in that the orifice (25, 46, 56) is an orifice for introducing the resin under the effect of a force field much greater than gravity, interstices ( it to i5) being provided and dimensioned between parts of the container respectively of the apparatus so as to allow on the one hand the escape of air through them when the resin penetrates therein, and on the other hand to prevent the resin from escaping to the atmosphere under the effect of these forces during the manufacture of the apparatus.

2. Electrical apparatus according to claim 1, characterized in that the interstices (i2, i5) are formed between the container (2, 52) and the connecting means (18).

3. Electrical device according to one of claims 1 or 2 and wherein the container comprises a case (2, 33) and a plug (11, 35) crossed by conductors (18, 36) and fitted into an opening of the 'case opposite the probe (4), characterized in that the orifice (25) is formed through the plug (11, 35).

4. An electrical appliance according to claim 1, in which the container comprises a case (2, 33) and a stopper (11, 35) crossed by the connecting means (18, 36), characterized in that the interstices (il, i3) are formed between the case ( 2, 33) and the plug (11, 35).

5. An electrical appliance according to claim 1, in which the container comprises a case (42), one end of which (44) is crossed by the connecting means (18), characterized in that the filling orifice (46) is constituted by an annular gap (46) between an open end of the case and an outer sheath (17) of the connecting means (18).

6. Electrical device according to claim 1, characterized in that said orifice (56) is disposed on an outer side wall of the container (52) and is surrounded by a surface (58) for the sealed application of a device resin introduction.

7. Electrical device according to claim 6, characterized in that the electrical connection means are arranged in a sheath (17) of a cable (18) having a diameter close to an inlet of the container (52) opposite to the probe.

8. Container for an electrical appliance according to claim 3, characterized in that the plug (11, 35) comprises a filling chimney (13) having the orifice (14) internally communicating with the internal volume (22) of the container and having externally a surface (15) for sealing with a resin introduction means, this chimney extending externally to the plug.

9. Container for an electrical appliance according to claim 8, characterized in that the chimney (13) has at its base (26) a fragility sufficient to allow its detachment from the plug (11, 35) after introduction of the resin into the container.

10. Container according to claim 8 or 9, characterized in that this chimney (13) is molded from a 2- \

single piece with plug (11).

11. Container for an electrical appliance according to claim 5, characterized in that it comprises a case (42) and a removable part (45) simultaneously surrounding the case (42) and the cable during the circulation of the resin, this part comprising a resin supply orifice (45a), the interstices (i4) being formed between the cable (18) and the removable part (45).

12. Method for drowning in resin the components of an electrical appliance located in a container of this electrical appliance, characterized in that:

- a - the container (59, 59 ", 59") is fixed in the eccentric position on a centrifuge rotor (60) and a filling orifice for the container is tightly connected with a supply channel (63, 63 " , 63 ") which extends to a central area (66) of the rotor;

- b - a predetermined quantity (Q) of resin in the fluid state is introduced into the central zone (66) and the rotor (60) is rotated to pass this resin by centrifugation from the central zone towards the interior of the container allowing air to escape from the container, and rotation is maintained substantially until the resin has firmed.

13. Method according to claim 12, characterized in that to establish a sealed contact between the filling orifice (25) of the container and the channel (63, 63 ', 63 ") of the rotor (60) is pressed at least a part of the container between two elements (64, 65) of the rotor (60) which can be separated from one another and which define the channel between them, so that the channel (63, 63 ') tightly follows a surface d tightness (15, 58) surrounding the orifice (14, 56).

14. Method according to one of claims

12 or 13, characterized in that one interrupts the resin supply when the quantity introduced - Q - is greater than the internal volume - v - of the container and less than the total volume - V - further comprising the channel and the central zone.

15. Method according to claim 14, characterized in that after firming of the resin, a core (73) of excess resin is broken flush with the external surface of the device (59).

16. Filling method according to claim 15, characterized in that the carrot is sheared during a rotor deceleration phase.

17. Filling method according to one of claims 12 to 16, characterized in that several receptacles (59 ', 59 ") are fixed on the rotor (60) so as to operate simultaneous fillings and to each benefit from them with the same amount of excess resinous material found in the central area.

18. The method as claimed in claim 17, characterized in that a quantity of resin Q is introduced into the central zone such that resin remains on the periphery of the central zone after the containers (59 ′, 59 ″) are completely filled and of supply channels (63 ′, 63 ″).

19. Filling method according to one of claims 12 to 18, characterized in that at least part of the rotor is heated to reduce the curing time of the resin.

20. Filling method according to one of claims 12 to 19, characterized in that a vacuum is established in regions of the rotor (60) close to the interstices at least during filling of the container.

21. Installation for implementing the method according to one of claims 12 to 20, characterized in that it comprises: - two rotor elements (64, 65) movable between a loading-unloading position in which they are spaced from one another and a refilling-centrifuging position in which they define between them at least one eccentric retaining housing for an apparatus container (59) to be filled with foam, a central cavity ( 66) and a channel (63) for supplying resin by centrifugation from the central cavity (66) to an orifice (25, 56) for filling the container;

- clamping means (92, 95 to 98) for pressing the two rotor elements one against the other so as to seal the resin between said elements and with a sealing surface (15, 58) provided on the container (59) around the orifice;

- means (89, 91, 102, 104) for introducing measured quantities of resin into the central cavity

(86);

- Means (82) for rotating the rotor elements (64, 65) together.

22. Installation according to claim 21, characterized in that the two rotor elements have sealing surfaces (84, 95) defined by elastomeric material towards each other.

23. Installation according to claim 21 or 22, characterized in that the housing (85) is directly arranged between two surfaces (95, 84) of elastomeric material of the family of silicones belonging to a pair of separable discs constituting said rotor elements (64, 65).

24. Installation according to claim 21 or 22, characterized in that at least one of the rotor elements (152, 182) comprises at least one pocket (156) shaped to receive the connection cable (18) in a coiled form.

25. Installation according to claim 24, characterized by a passage (161) for a part of cable between the housing for the appliance container (59) and the pocket (156).

26. Installation according to one of claims 24 or 25, characterized in that the pockets (179) are arranged in a plate (178) of one of the rotor elements, the housings (175) for each of several containers ( 59) to be filled simultaneously, being essentially arranged between elastic means that can be combined (173) with said plate and having a diameter less than that of the plate. 0 27. Installation according to one of claims

21 to 26, characterized in that the two rotor elements (64, 65) are movable relative to each other parallel to their common axis of rotation (YY ').

28. Installation according to one of claims 5 21 to 27, characterized by compression means (190) applying to the device (59) undergoing filling of the longitudinal forces capable of preventing dissociation of the device during rotation.

29. Installation according to claim 28, o characterized in that these compression means (190) comprise a counterweight (191) associated with a movement return lever (193) articulated to one of the rotor elements (64) so that the efforts are developed by the centrifugal force and in the opposite direction thereof. 5 30. Installation according to one of claims

21 to 29, characterized in that the rotor elements (64, 65) consist of two massive discs made of elastomeric material.

31. Installation according to one of claims 21 to 29, characterized in that the rotor elements

(200) comprise at least one composite disc comprising a metal base (201) whose recesses intended to define the central zone, the channel, the housing for the apparatus container (59) are, at least in part, locally covered with '' an elastomeric material (203).

32. Installation according to one of claims 21 to 31, characterized in that it comprises a rotary step-by-step table (124) pivoted on a base fixed to the ground and comprises at least three turntables (121, 122, 123) which the table passes successively according to an operation in a carousel, at loading-unloading, filling and centrifugation stations.

33. Installation according to claim 32, characterized in that the three turntables are driven by a single motor capable of being coupled to them by clutches controlled by an automaton.

34. Installation according to one of claims 32 or 33, characterized in that the energy necessary for the step-by-step rotation of the table is borrowed from the energy stored by at least one of the turntables.