FR2538176A1 - Safety power-outlet socket, especially for an explosive atmosphere - Google Patents

Abstract

For interaction with the pins 26 of a plug 11, this socket comprises at least two phase or neutral cavities 47. According to the invention, it comprises one fireproof safety chamber 30 per set of cavities 47 and, in this chamber a contact piston 40 is mounted so as to move axially. Application in particular to safety power outlets for an explosive atmosphere.

Description

 The present invention relates generally to so-called safety sockets, and more particularly relates to those of these sockets which are intended to be used in an explosive atmosphere.

 As is known, the sockets, or, more generally, the connectors intended to connect electrically, and at will, two cables, comprise, on the one hand, a female part, or base, equipped , in addition to a possible earth cell, of at least two phase or neutral cells each respectively electrically connected to the conductors of a first of these cabals, and, on the other hand, a male part, or plug, equipped with pins , which, each respectively connected to the conductors of the second of these, are intended to be each respectively engaged in such cells, for the desired electrical connection.

 In an explosive atmosphere, and for obvious safety reasons, it is important that the contact between pins and cells takes place in a suitably confined enclosure, commonly known as explosion-proof safety chamber, so that, if a spark occurs during such a contact, both when the current is established and when it is cut off, the explosion liable to result is limited to this safety chamber, without propagation of the corresponding flame outside of it.

 To date, such a safety chamber is common to all of the cells of the base.

 Several arrangements have therefore been proposed, all of which assume mechanical locking of the plug on the base.

 According to a first of these provisions, a bayonet mount is provided between the plug and the base, and, more often than not, it is also provided therein, for example in a separate compartment, a switch, which, arranged upstream cells, systematically de-energizes them so as to allow the extraction of the plug, and, conversely, to prevent their introduction when the cells are energized.

 According to a variant, which is in practice accepted by regulations only for sockets whose nominal current is less than 10A for 250V, there is no such switch, but a cover prohibited to the pins the plug direct access to the socket in the base.

 Upon engagement of the plug, a rotation of the latter with respect to the base ensures, on the one hand, its mechanical locking on the latter, and, on the other hand, that is, in the first case, the closing of the switch implemented, that is, in the second case, the retraction of the cover controlling access to the cells of the base.

 According to a second arrangement already known, a key is provided between the plug and the base, which controls the mechanical locking of this plug on this base, and which ensures, by acting simultaneously on a switch located in a compartment separate from the latter, establishing the current upstream of the cells, or cutting it off.

 In practice, such arrangements lead to relatively complicated embodiments, requiring a switch or a cover combined with a mechanical locking device, and therefore relatively bulky and expensive.

 A general object of the present invention is a provision making it possible to avoid these drawbacks, and in particular allowing an automatic de-energization of the cells of the base during the separation of the plug, without the use of any switch or of any cover, and without mechanical locking device.

 More specifically, it relates to a socket for a safety socket outlet, in particular for an explosive atmosphere, of the type comprising, in a body of insulating material, for cooperation with the pins of a socket outlet plug, in addition to a possible earth cell, at least two phase or neutral cells, this base being generally characterized in that it comprises at least as many separate explosion-proof safety chambers as there are phase cells or neutral, said phase or neutral cells each being individually arranged in said explosion-proof safety chambers.

 It is thus advantageously possible to treat each of the pin-cell assemblies in question individually.

 In practice, for this purpose, and according to the invention, in an explosion-proof safety chamber corresponding to such a spindle-cell assembly are located, on the one hand, on the bottom of this safety chamber, a contact member, and, on the other hand, mounted axially movable between two end of travel stops, in said chamber, a contact piston, which divides the latter into two portions, and which, at the front, on the side of its outlet, presents the associated socket.

 Preferably, the contact member thus used in an explosion-proof safety chamber is itself a pin, called below, for simple convenience, base pin, to distinguish it from the pins of the plug, this pin of base protrudes axially on the bottom of the explosion-proof safety chamber which team, the corresponding contact piston has, at the rear, on the side of said bottom, a cell, by which it is intended to cooperate with said base pin, and the stroke of said contact piston in said explosion-proof safety chamber is made sufficient so that, when it is in abutment against the front end-of-travel stop, on the outlet side of said chamber, it is free from any contact with the spindle base forming the associated contact member.

 Anyway, when removing the plug from the base, the pins of the latter drive the contact pistons with the cells before which they are each respectively engaged, and before they are released -same of these contact pistons, they cause, by the mere fact of their own withdrawal movement, a disengagement of these contact pistons from the base pins or other associated corresponding contact members.

 Thus, the security conditions to be observed are very simply ensured.

 The conditions being equal, moreover, the base is itself advantageously simplified and its size is reduced.

 In addition, since no particular device such as a bar or key mounting is to be provided, the pins of the plug can be simple pins, established according to a usual layout, and therefore respecting the interchangeability ratings provided for by the official standards in matter.

The characteristics and advantages of the invention will become apparent from the description which follows, by way of example, with reference to the appended schematic drawings in which
Figure 1 is a view, partly in elevation, and partly in section, along the broken line II of Figure 2, of a safety outlet using a base according to the invention;
Figure 2 is a plan view of this base, along the line II-II of Figure 1;
Figure 3 shows, on a larger scale, the detail of Figure 1 identified by an insert III thereon;
Figure 4 is a view similar to that of Figure 3, for the configuration of the base corresponding to the withdrawal of the associated plug.

 The safety outlet shown in these figures usually comprises a female part 10, or base, and a male part 11, or plug.

 In the embodiment shown, the base 10 is carried by a housing 12, called "increased safety", by means of which it can be attached to any support.

 Since such a housing 12 is well known in itself, and not forming part of the present invention, it will not be described in detail here.

 It will suffice to indicate that, for the implantation of the base 10, it comprises a well 13, on the bottom 14 of which said base 10 is supported by a flange 15 which it projects externally projecting transversely for this purpose, while crossing the central opening 16 of this bottom 14, and while providing between it and the side wall of said well 13 an annular volume suitable for the insertion of the skirt 18 of the plug 11, that on said flange 15 of the base 10 is superimposed a gasket 19, for support of the edge of said skirt 18 of the plug 11, and that, on the outer wall of the well 13, is hinged a cover 20 suitable for sealing it in the absence of a such sheet 11.

 In practice, in the embodiment shown, and in a manner also known per se, the side wall of the well 13 locally forms a longitudinal groove 21 capable of constituting a polarizing device, the skirt 18 of the plug 11 comprising locally, in correspondence , over at least part of its height from its edge, a bead 22 complementary to such a groove.

 The sheet 11 is also not part of the present invention, and, well known to those skilled in the art, it will not be described in detail here.

 I1 suffice to specify that, externally, its skirt 18 has transversely projecting a flange 23, for support on the edge of the well 13 of the housing 12, and that, internally, it comprises, projecting on a base 24, in addition to a possible earth pin 25, as shown, at least two phase or neutral pins 26.

 In practice, in the embodiment shown, and for simplification of the figures, only two pins 26 have been provided; these are phase pins, the current outlet being assumed to interest a single-phase network.

 In a manner known per se, the base 10 forms a body of insulating material, and, for cooperation with the pins of the plug 11, it comprises, in addition to a possible earth cell 28, as shown, at least two phase cells or neutral 29.

 As indicated above, only two cells 29 have been provided, and these are phase cells.

 According to the invention, the base 10 comprises at least as many separate explosion-proof safety chambers 30 as there are phase or neutral cells 29, said phase or neutral cells 29 being each individually arranged in said chambers. explosion proof safety 30.

 In practice, in the embodiment shown, the number of explosion-proof safety chambers 30 used is equal to that of the phase or neutral cells 29, no explosion-proof safety chamber being provided for the cell of earth 28.

 Indeed, such an earth cell 28 does not normally require by itself the implementation of such an explosion-proof safety chamber.

 But, of course, there would be no escape from the present invention if this procedure were carried out for this earth cell 28 as for the phase or neutral cells 29.

 In practice, also, on the internal or rear side, the base 11 is closed by a bottom 32, which is common to the various explosion-proof safety chambers 30, and which, for each of these, includes a tubular end piece 33 which ensures interlocking with respect to such an explosion-proof safety chamber 30.

 The axial length L of such a tip 33, which corresponds to a line of flight, is made sufficient to meet the requirements to be met in this area.

 On the external side, or front, the base 10 comprises, for each explosion-proof safety chamber 30, a collar 34, which extends transversely in such an explosion-proof safety chamber 30, and the opening 35 of which defines the outlet to the outside of it.

 Of course, the diameter D of this opening 35 corresponds to that of the pins 26 of the plug 11.

 Of course, also, the axial length L ′ of the collar 34, which also defines a line of flight, is at least equal to the axial length L specified above, for compliance with the standards in the matter, and is for example equal to this one.

 It is in fact thanks to such provisions that a security chamber 30 constitutes an explosion-proof security chamber.

In an explosion-proof safety chamber 30 thus formed, there are arranged, according to the invention, on the one hand, on the bottom 32 of this explosion-proof safety chamber 30, a contact member 37, and, on the other hand, mounted axially movable, in practice between two stops
limit switch 38, 39, one rear, the other front, in the embodiment shown, a contact piston 40, which divides said explosion-proof safety chamber 30 into two portions, and which, at the front, on the side of the outlet 35 thereof, has the associated phase or neutral cell 29.

In the embodiment more particularly shown in the figures, the contact member 37 is a pin, called below for convenience, base pin
In practice, this base pin 37, which is metallic, projects axially on the bottom 32 of the explosion-proof safety chamber 30 which it equips, and it comprises in one piece a tubular tail 42, which passes through said bottom 32 , by virtue of an axial bore 43 thereof, the axial length L ", for the same reasons as above, is preferably at least equal to the axial length L specified above, and in the axial bore 44 which can be engaged, for its crimping, the conductive core of the conductor 45 concerned.

 Jointly, for cooperation with the corresponding base pin 37, the contact piston 40 has, at the rear, on the side of the bottom 32 of the glaring anti-safety chamber 30 in which it is slidably mounted, a cell 47, through which it is adapted to cooperate with said base pin 37.

 In practice, such a contact piston 40, which is metallic, therefore presents thus, each arranged respectively back to back on either side of a common central base 48 by which it is slidably engaged in the explosion-proof safety chamber 30 that it equips, on the one hand, in the direction of the outlet 35 thereof, the corresponding phase or neutral cell 29, and, on the other hand, in the direction of its bottom 32, the cell 47 .

 In practice, too, and in a manner known per se, each of these cells 29, 47 is circularly fragmented by slots 50, in order to be able to have a certain elasticity radially, and thus elastically tighten the corresponding pin 26, 37 when it is in contact with it.

 Preferably, for such tightening, each of the cells 29, 47 is elastically subjected to a radial prestress with respect to the corresponding pin 26, 37.

 For example, and in a manner known per se, this is due to the effects of a hooping ring 51, forming a spring, which annularly surrounds such a cell 29, 47, outside of the latter.

 In practice, in the embodiment shown, the cells 29, 47 have, overall, the same axial length, and the same constitution.

 In practice, too, the stroke of the contact piston 40 in the explosion-proof safety chamber 30 which it equips is made sufficient so that, when it is in abutment against its front end-of-travel stop 39, on the outlet side 35 of said explosion-proof safety chamber 30, as shown in FIG. 4, it has no contact with the base pin 37 forming the associated contact member.

 Preferably, it is then separated from the latter by a distance D ′, which, corresponding to a distance in the air after drawing out, is made sufficient to meet the standards in the matter.

 In the embodiment shown, the rear end-of-travel stop 38 associated with the contact piston 40 is formed by the bottom 32 of the explosion-proof safety chamber 30 which it equips, and its front end-of-travel stop 39 is formed by the collar 34 thereof.

 Finally, and as shown, such a contact piston 40 is preferably associated with releasable latching means capable of strengthening its position when it is in abutment against its front end-of-travel stop 39.

 In the embodiment shown, these disengageable snap-fastening means comprise, on the one hand, an elastic ring 53, for example an elastic ring opened by a slot, which is engaged in a groove 54 annularly provided for this purpose at the periphery external of the contact piston 40, in the central zone of the central base 48 thereof, and, on the other hand, a groove 55, which, in a complementary manner, is also annularly provided for this purpose on the internal wall of the corresponding explosion-proof safety chamber 30, for engagement of said elastic ring 53.

 Preferably, the distance 1 axially separating each of the sides of the groove 54 of the contact piston 40 from the corresponding free surface of the central base 48 thereof is at least equal to half of the axial length L specified below. above.

 Preferably, by construction, by an appropriate choice of the characteristics of the various constituents in question, it is ensured that, with respect to the corresponding pins 26, 37, the radial prestressing which is the object, for the reasons explained above, the front socket 29 of the contact piston 40 is greater than that of its rear socket 47.

 Jointly, it is also made so that the axial force due to the tightening of a plug pin 26 by such a front socket 29 of the contact piston 40 under the effects of the radial prestress thereof is greater than the sum of the axial force due to the tightening of the corresponding base pin 37 by the cell 47 thereof under the effects of the radial prestressing of this rear cell 47, on the one hand, and of the axial force due to the friction, on the internal wall of the explosion-proof safety chamber 30, of the elastic ring 53 carried by said contact piston 40, on the other hand.

 Consequently, when, a plug 11 being engaged with the base 10, this plug rî is removed, there is first of all, firstly, a drive, by the pins 26 thereof. , of each of the contact pistons 40 that said base 10 comprises.

 During this training, each of these contact pistons 40 emerges from the corresponding base pin 37.

 The driving of the contact pistons 40 continues, these contact pistons 40 abut against their front end-of-travel stop 39, as shown in FIG. 4, and the elastic ring 53 which they carry, being then in line with the groove 55 of the explosion-proof safety chamber 30 concerned, and, taking an deployed configuration by elasticity, it engages in said groove 55.

 From this instant, and, in a second step, the pins 26 of the plug 11 are released in their turn from the contact pistons 40.

 However, the corresponding disconnection advantageously takes place even when these contact pistons 40 are de-energized, since at a distance from the base pins 37.

 In addition, the elastic ring 53 carried by the contact pistons 40 confirming the position of the latter in abutment against their front end-of-travel stop 39, these contact pistons 40 advantageously remain permanently de-energized in the absence of sheet 11.

 Conversely, when a plug 11 is engaged on a base 10, there is, first of all, at first, an engagement of the pins 26 of this plug 11 in the front cells 29 of the contact pistons 40, without drive of these.

 In fact, as explained above, the axial force required to disengage the disengageable latching means associated with these contact pistons 40 is greater than the axial force that opposes the engagement of a plug pin 26 , due to its radial prestress, the front cell 29 of such a contact piston 40.

 It is therefore this front cell 29 which then yields the first.

 In a second step, when, the pins 26 of the plug 11 having arrived, in the embodiment shown, at the bottom of the front cells 29 of the contact pistons 40, the engagement of this plug 11 on the base 10 is continued, the axial force required to disengage the disengageable latching means associated with these contact pistons 40 is in turn overcome, and these contact pistons 40 are therefore driven by the plug 11.

 During this drive, the contact pistons 40 engage in their turn, by their rear cells 47, on the base pins 37, possibly until they stop against their rear end-of-travel stop 38, as shown, depending on the possible entry race for sheet 11.

 As will be understood, and according to the process detailed above, the disengageable latching means associated with the contact pistons 40 ensure, on the one hand, that the engagement of the plug pins 26 in these contact pistons 40 is done with complete certainty while they are de-energized, without contact with the associated base pins 37, and, on the other hand, that no false maneuver is possible, if, for example , during an engagement of the sheet 11 on the base-10, there is a premature withdrawal of this sheet 11, before this engagement has reached its normal term.

 In fact, in this case, by the pins 26 of the plug 11 with which they are necessarily engaged, the contact pistons 40 are necessarily brought into abutment against their front end-of-travel stop 39, without risking being abandoned in an intermediate position, for which they could be in contact with the corresponding base pins 37, and therefore be then energized.

 Of course, the present invention is not limited to the embodiment described and shown, but encompasses any variant.

 In particular, provision may be made for at least one of the cells of the contact piston according to the invention, and, for example, for each of these, an internal shoulder capable of cooperating in abutment with the corresponding pin. if such a shoulder is provided for the rear cell, it may, if necessary, constitute by itself the rear end-of-travel stop of the contact piston according to the invention.

 Such an arrangement advantageously makes it possible to minimize the necessary engagement stroke, while leaving the cells of the contact piston according to the invention all the desirable length so that they have good elasticity.

 In addition, to have different radial preloads of these cells vis-à-vis the corresponding pins, the base pins can be made of slightly smaller diameter than the plug pins.

 Such an arrangement advantageously makes it possible to have a symmetrical contact piston, which simplifies manufacture and assembly.

 Furthermore, the field of application of the invention is not limited to the case where, in the case of a single-phase installation, two phase cells are used.

 On the contrary, it extends for example as well to three-phase installations, for which three phase cells are used, with, optionally, a neutral cell, in addition to a possible earth cell.

Claims (11)

 1. Base for safety socket outlet, in particular for an explosive atmosphere, of the type comprising, for cooperation with the pins (26) of a socket outlet plug (11), in addition to a possible earth socket (28), at least two phase or neutral cells (29), characterized in that it comprises at least as many explosion-proof safety chambers (30) as there are phase or neutral cells (29), said cells phase or neutral (29) each being individually arranged in said explosion-proof safety chambers (30).  2. Base according to claim 1, characterized in that, in an explosion-proof safety chamber (30) are arranged, on the one hand, on the bottom (32) thereof, a contact member (37), and, on the other hand, mounted axially movable in said chamber, a contact piston (40), which divides said chamber into two portions, and which, at the front, on the side of the outlet (35) thereof, has the associated phase or neutral cell (29).  3. Base according to claim 2, characterized in that the contact member (37) is a pin, hereinafter called base pin, which projects axially on the bottom (32) of the explosion-proof safety chamber (30 ), the contact piston (40) has, at the rear, on the side of said bottom (32), a cell (47), by which it is adapted to cooperate with said base pin (37), and the stroke of said contact piston (40) in said chamber is made sufficient so that, when it is in abutment against a front end-of-travel stop (39), on the outlet side (35) of said chamber, it is free of any contact with the base pin (47) forming the associated contact member.  4. Base according to any one of claims 2, 3, characterized in that the front end-of-travel stop (39) of the contact piston (40) is formed by a collar (34) which extends transversely in the explosion-proof security chamber (30), the opening of which defines the outlet (35) thereof.  5. Base according to any one of claims 2 to 4, characterized in that a rear end-of-travel stop (38) is provided for the contact piston (40) in the explosion-proof safety chamber (30), said rear end stop (38) being for example formed by the bottom (32) of said chamber (30).  6. Base according to any one of claims 2 to 5, characterized in that the contact piston (40) are associated with releasable latching means capable of strengthening its position when it is in abutment against its abutment front limit switch (39).  7. Base according to claim 6, characterized in that said disengageable latching means comprise an elastic ring (53) engaged in a groove (54) annularly provided for this purpose at the outer periphery of the contact piston (40), in the central zone thereof, and a groove (55) annularly provided in a complementary manner on the internal wall of the explosion-proof safety chamber (30), for engagement of said elastic ring (53).  8. Base according to claim 3, characterized in that, each of the cells (29,47) of the contact piston being elastically subjected to a radial prestress vis-à-vis the corresponding pin, for example under the effects of a hooping ring (51) forming a spring, the radial preload of the front cell (29) is greater than that of the rear cell (47).  9. Base according to claims 7, 8, taken together, characterized in that the axial force due to the tightening of a plug pin (26) by the front socket (29) of the contact piston (40) under the effects of the radial prestress thereof is greater than the sum of the axial force due to the tightening of the base pin (37) by the rear socket (47) of said contact piston (40) under the effects of the radial preload of the latter, on the one hand, and of the axial force due to friction, on the internal wall of the explosion-proof safety chamber (30), of the elastic ring (53) carried by said contact piston (40), on the other hand.  10. Base according to claims 6, 8, taken together, characterized in that the axial force that opposes the engagement of a plug pin (26), due to its radial preload, the front socket ( 29) of the contact piston (40), is less than the axial force required to disengage the disengageable latching means associated with said contact piston (40).  11. Base according to any one of claims 1 to 10, characterized in that it is carried by a "increased safety" housing (12).