EP0106931B1 - Socket having a snap-action connection and disconnection - Google Patents

Description

The invention relates to a socket outlet comprising a base connected to the power supply line and a combined plug serving the user device and meeting safety standards under which the base contacts must remain de-energized when the plug is removed from the base.

More specifically, the invention lends itself particularly well to the production of so-called ADF sockets intended for use in an explosion-proof environment.

For such sockets, the KENTER device is known (DE-C-337290) in which the plug and socket contacts are brought to cooperate by simple translation under the action of a push-handle which, itself, is then locked on the base by rotation. This device offers little security, the plug can be inserted using any tool, or even with the hand without fitting the push handle forming the enclosure cover and does not comply with the aforementioned standards imposing the de-energizing the base contacts during separation. So that the contacts of the base remain de-energized, when the plug and the base are separated, the known devices generally associate with the socket-outlet, a switch arranged between the supply line and the base and operated, at least for the engagement, by the rotation of said base after fitting of the plug. Such an arrangement has the disadvantage of requiring a flexible connection between each contact of the base and the corresponding arrival terminal, a risk of deterioration existing at each end of each flexible connection as a result of successive operations.

Another possibility is to provide an interlocking of the plug on the base by simple translation, with locking, followed by the operation of a switch device cutting the electrical connection between the incoming terminals and the base contacts. This is the case of the BERRY device (US-A-3041420) with its rotary switch device controlled by a handle.

However, in all cases, if it is then possible to provide for an abrupt break thanks, for example, to an elastic means released by an independent mechanism, the engagement remains conventional and is therefore not entirely satisfactory for use in explosive environment. This is the case of the aforementioned KENTER and BERRY devices.

The use of a plug with elastic pressure contacts overcomes these drawbacks.

To this end, the invention relates to a socket outlet constituted, on the one hand, by a plug comprising a body in which is rigidly mounted an insulating support carrying the plug pins intended to be connected respectively with the elementary conductors of the multi cable. -conductor of use and, on the other hand, a base comprising a body including the terminals of arrival of the supply line and, rotatably mounted in said body, an insulating block dug with wells in each of which is arranged, in a tubular piece, a base pin slidably mounted under the action of an elastic means urging it outwards to a stop position and intended to cooperate elastically with a conjugate pin of the plug, when the plug and base, the bodies of which carry combined guiding and locking means, under the effect of a movement associating an axial displacement and a rotation of one relative to the other carried out successively or simultaneously, the plug pins driving the insulating block in this rotation. Each of the sliding base pins can be either a solid pin cooperating with the plug pin which is conjugated to it by end contact, or a pin comprising at its end a socket intended to come to cap the end of the corresponding plug pin . The socket according to the invention is remarkable in that the electrical connection between each arrival terminal and the corresponding base pin comprises the coupling of two contact grains, one of which is connected to the arrival terminal and the another is carried by the end of a conductive arm secured to the spindle considered and able to pivot around the lower part of the tube and that when the plug and the base are not fitted, the grains to be joined are arranged relative to the axis of the base in different relative angular positions, the rotation of the interlocking movement bringing them into angular coincidence, that means are provided for first of all keeping the arm stationary relative to the insulating block and releasing it substantially at the end of the relative rotation of the plug with respect to the base, then allowing it to pivot around the corresponding tube to achieve the abrupt coupling of the two contact grains under the effect of the partial release of the energy accumulated by elastic means during said relative rotation, while during reverse rotation allowing the separation of the plug and the base, the grain carried by the arm escapes the opposing grain, the rest of the energy accumulated by the means elastic ensuring the abruptness of the rupture and that finally a stop causes towards the end of this reverse rotation, the return of the arm to its initial position of immobilization with respect to the insulating block.

• - La figure 1 est une coupe axiale simplifiée d'une prise de courant conforme à l'invention selon la ligne brisée 1-1 de la figure 2.
• - La figure 2 est une coupe par II-II de la figure 1.
• - Les figures 3A à 3F semblables à la figure 2 avec une orientation différente, montrent les différentes phases du fonctionnement lors de l'enclenchement (figures 3A, 3B, 3C) et de la rupture (figures 3D, 3E, 3F et 3A).

Other characteristics of the invention will appear on reading the following description of an embodiment, made with reference to the appended drawings all simplified or schematic in which:

• FIG. 1 is a simplified axial section of a socket outlet according to the invention along the broken line 1-1 of FIG. 2.
• - Figure 2 is a section through II-II of Figure 1.
• - Figures 3A to 3F similar to Figure 2 with a different orientation, show the different phases of operation during engagement (Figures 3A, 3B, 3C) and rupture (Figures 3D, 3E, 3F and 3A).

In the drawings, the reference 11 designates a plug of conventional design for an industrial outlet, the body 11a of which carries an insulating disc 13 on which the plug pins such as 17 are mounted, the other plug pins having no not shown to simplify the drawing. The departures of the conducting wires 19 are effected by wire clamps 15 integral with the pins and the multi-conductor cable, not shown, the elementary conductors of which lead respectively to each pin, passes through the gland, in itself known, designated in its generality by 21. The plug body 11 also has, externally, a locking lug 23, a bayonet lug 25 and possibly, a flange provided with an annular seal not shown, intended to cooperate with corresponding elements of the base when 'this is an ADF socket.

The base, to which the supply wires such as 48 lead, of which only one has been shown in FIG. 1, is designated by the general reference 10 and comprises a housing 12 made of insulating material, secured to an upper annular body. 14 having a shoulder-bearing 14b for its fixing according to explosion-proof security standards, called ADF standards, on a load-bearing wall using conventional means which have not been shown.

According to arrangements which are known per se, the body 14 carries an axis 18 on which a hook 20 is articulated biased by a spring 22 towards the axis of the device.

The annular body 14 has a large axial aperture carrying a thread 14a which cooperates with the corresponding thread 28a by which a block of insulating material 28 can be engaged in the body 14 to present, in the operating position of the assembly, a possibility of rotation coaxially with said body, that is to say in fact, with respect to the base 10 of which the latter forms an integral part.

In the block 28 are provided the wells such as 30 in which the tubular sheaths 29 are crimped. In these sheaths are housed pins 31 intended to cooperate by end contact with the plug pins 17; in the figures, only one plug pin and one base pin have been shown, in order to simplify the drawing; it is however a base with four contacts without counting the earth contact not shown.

Between the upper part of the block 28 and the body 14 is formed an annular groove 32 intended to receive the tubular end 11b of the plug body 11a. In addition, the internal face of the body 14 has a ramp for bayonet connection intended to cooperate with the lug 25 carried by the plug, said ramp comprising in a known manner an access corridor of axial direction relative to the base and a corridor locking located in a transverse plane thereof.

The block 28 has a cylindrical axial extension 35 on the underside of which is fixed by a screw 38 a disc 37, removable for mounting the device.

The base pins 31 are slidably mounted in their tubular sheaths 29 against the tension of springs 42 working under compression between the lower end of said spindle and the disc 37. Furthermore, each spindle, which can rotate in its sheath, carries this same lower end an arm 51 transverse to its axis, made of electrically conductive material, the end of which carries a contact grain 45 and which is pivotally mounted around the lower end of the tubular sheath 29.

The line contacts such as 55 are respectively arranged at the ends of the arms 51 and they are connected, by the conductive strips 46 and the arrival terminals 47, to the line wires such as 48.

Around the extension 35 of the block 28 and coaxially with it is arranged a hooking piece 49 in the general shape of a star molded in insulating material, This star piece has a number of arms equal to the number of base pins and can rotate around the extension 35. A spacer spring 58 (FIGS. 3A-3F) disposed between a bearing surface integral with the disc 37 and a bearing surface integral with the attachment piece 49 ensures the latter to rotate when the block 28 is moved towards the latching position, the inverted rotation drive of the part 49 being provided by a lug 59 (FIG. 3B) carried by the disc 37 and which can constitute the bearing of the spring 58 on this disc. The rotation of the part 49 towards the latching position is limited by a stop 56 disposed on the bottom of the housing 12 of the base 10, while the block 28 has not yet completely completed its travel, this difference in amplitude of rotation being made possible by the compression of the spring 58.

Each arm 51 is subjected to the action of a helical spring 50 threaded on the lower part of the corresponding tubular sheath 29. One of the end branches 50a of the spring 50 extends towards the periphery of the housing 12 to engage and remain trapped in a groove 44 parallel to the axis of the device and limited by two abutment ribs 44a and 44b making protruding inward on the wall of said housing. The other end branch 50b first extends parallel to the arm 51 and is then bent downward at a right angle to become parallel to the axis of the device and to engage in conjugate perforations formed at the end of the arm 51, the end 52 of said branch 50b completely transversing this end to come at the level of the hooking part 49.

Each branch of the hooking piece 49 in star shape has at its end, on the face: facing towards the latching position, a rounded guide strip 43, leading to a notch 53, for the end 52 of the spring 50 .

Preferably, at least one latch 41 disposed in a housing 41a at the bottom of the housing 12 and subjected to the action of a spring 41b urging it outside said housing cooperates with a perforation 39 of the disc 37 to lock the insulating block 28 in the rest position when the plug 11 and the base 10 are separated. The perforation 39, in this position, is plumb with a well 30 and the corresponding pin 31 has an extension 34 which engages in said perforation until it is flush with the lower face of the disc 37 at the end of the axial movement for inserting the plug into the base, so as to erase the latch 41. This arrangement, ensuring the locking of the insulating block 28 when the plug 11 is removed, prevents any rotation towards the latching position, which guarantees that the power is turned off. base pins.

A lock is also provided in the engaged position. It is obtained automatically at the end of rotation of the plug 11 by engaging the hook 20 in a fork lug 23. Unlocking is achieved by tilting the hook 20 against the action of the spring 22. It is necessary note that the hook 20 can in the rest position (separate plug and base), be used for attaching a cover (not shown) hinged on the annular upper part 14 of the base 10 opposite said hook.

Finally at least one boss 57 projecting inwardly on the wall of the housing 12, at the ends of the arms 51, prohibited after rupture, the rotation of the insulating block 28 towards the engagement position as long as the arm 51 n 'has not been returned to its hooking position, that is to say, until the rotation towards the position of separation of the plug and the base has not been continued until the end.

Referring to Figures 3A to 3F we can follow the different phases of operation. Starting from the position in which the plug 11 and the base 10 are separated, the plug is fitted onto the base and, thanks to their combined guide elements, each pin 17 of the plug comes opposite a well 30. It is then possible to perform the axial translation which constitutes the first movement of the bayonet engagement. The base pins 31 are then pushed back against the springs 42 and in particular that (or those) carrying an extension 34 which erases the corresponding latch 41 thereby making the block 28 free to rotate (FIG. 3A). In this position, the end 52 of each spring 50 is hooked into the corresponding notch 53 of the attachment piece 49 and the arms are immobilized.

We then print on sheet 11 the rotation constituting the second movement of the bayonet engagement, Here this rotation, seen axially from above, takes place in the indirect direction (clockwise) according to the arrow F1 ( Figure 3B). The plug pins drive the block 28 and its disc 37. The branch 50a of each spring 50 held captive in the groove 44 is supported on the abutment rib 44a and the spring 50 is tensioned. Thanks to the spring 58, the hooking piece 49 in a star follows the rotation of the block 28 until one of its branches comes into contact with a stop 56 secured to the housing 12 of the frame 10. The block 28 can continue its rotation over a small amplitude by compressing the spring 58 and as the block 28 drives the arms 51 with their springs 50, the ends 52 of the springs are released from the notches 53 and the arms 51 pivot suddenly towards the wall of the housing 12 under the action of the elastic energy accumulated by the springs during rotation. The stop 56 is located in such a way that the contact grain 45 of each arm comes to bear against the opposing contact grain 55 connected to a line terminal 47. The device is then in its latching position (FIG. 3C) and, as said above, is locked there by the cooperation of the hook 20 and the lug 23. Preferably the stop 56 is arranged so the arms 51 pivot slightly before the contact grains 45 are exactly in the axis of the contact grains 55. Thus the rotation continues for a short time while the opposing contacts are already engaged, which determines a self-cleaning of contacts by friction. Similarly, the contact grains at the end of the pins 17 and 31, respectively of the plug and of the base, are subjected to a self-cleaning by friction during the pivoting of the arms 51, integral with the pins 31.

In the engaged position (FIG. 3C) the springs 50 are not completely relaxed, the pivoting of the arms 51 has been stopped by the contacts 55 before said springs have released all the accumulated energy.

To obtain the break in the connection, you must first unlock the plug by acting on the hook 20 and then activate the plug in rotation in the direct direction (arrows F2). The block 28 is driven by the pins 17 with its disc 37 and the lug 59 integral with the disc 37 in turn drives the attachment piece 49. At the start of this maneuver, each contact grain 45 slides over the antagonist grain 55 up to 'to escape it (Figure 3D) and suddenly pivots towards the wall of the housing 12 under the effect of the rest of the elastic energy accumulated by the spring 50 (Figure 3E). There is thus produced an abrupt rupture by fall. The springs 50 are then completely relaxed and no longer exert any stress on the arms 51. It should be noted that in this position, any return to the latching position is made impossible by the boss 57 which opposes the passage of the head of the corresponding arm 51.

Towards the end of the rotational movement bringing the lug 25 of the plug opposite the axial channel of the bayonet lock, rotation limited by a stop acting on the disc 37 (here it is the stop 56 already used for the part 49 in the engagement rotation, which plays this role), the brance 50b of each spring 50 is supported on the abutment rib 44b (FIG. 3F) which causes the continuous pivoting of the corresponding arm 51 towards the axis of the device, l 'end 52 of the spring then comes into contact with the guide ramp 43, slides on this ramp and is received in the notch 53 (Figure 3A). The arms 51 are again immobilized and a new latching maneuver ment can be undertaken.

In all of the foregoing, the plug and socket pins (respectively 17 and 31) cooperate elastically, the socket pin 31 being subjected to the action of a spring 42 urging it towards the plug pin 17. So that there is elastic contact so it is clear, as has been said, that the pin 17 pushes the pin 31 during the axial movement of driving the plug 11 into the base 10. The arm 51 which is integral, with its grain contact 45, of pin 31 follows this movement and there is therefore, with respect to the axis of the supposed vertical device, a difference in level of contact grain 45 between the rest position (plug and base separated) and the position and it must be taken into account for the position of the antagonistic contact grain 55. This difference can be very small but it is advantageous that it is greater than the diameter of a contact grain because then, in the rest position, the grains to be coupled 45 and 55 are located not only in different relative angular positions but also entirely at different levels which increases safety, a rotation of the block 28 without introduction of the plug, for example in the event of failure of the locking means (41, 41b), which cannot then cause the 'engagement.

If this additional security is dispensed with, it is then possible to simplify the device by mounting the non-sliding pin 31 in its tubular sheath 29 and by producing it in the form of a cell pin, but this is there of a technical equivalence included within the framework of the invention, like besides other modifications of details.

Similarly, a socket according to the invention - can use all the arrangements known on other electrical connection devices (angular offset of at least one contact, insulating support and block with variable angular position, single or double safety disc, etc ...).

Claims (10)

1. A plug and socket assembly constituted firstly by a plug (11) comprising a body (11a) in which an insulating carrier (13) carrying the plug pins (17) designed to be connected respectively to the component conductors of the multi-conductor service cable is fitted rigidly and secondly, of a socket (10) comprising a body incorporating the input terminals (47) of the power supply line and an insulating block (28) which is mounted so as to rotate in said body and exhibits wells (30) each of which accommodates a tube (29) which accommodates a socket pin (31) which slides through the action of an elastic means (42) moving it outwards to a stop position and is designed to cooperate elastically with a corresponding pin (17) of the plug when the plug (11) and the socket (10) are brought together, the bodies of these carrying combined means for guiding and locking under the effect of a movement combining an axial movement and a rotary movement of the one in relation to the other effected successively or simultaneously, the plug pins (17) driving the insulating block (28) in this rotary movement, characterised in that the electrical connection between each input terminal (47) and the corresponding socket pin (31) is made by coupling two contact studs (45 and 55) of which one (55) is connected to the input terminal (47) and the other (45) is carried by the end of a conducting arm (51) rigidly secured to the pin (31) in question and capable of pivoting about the lower part of the tube (29), and in that when the plug (11) and the socket (10) are not engaged together, the contact studs (45 and 55) to be connected are disposed in different relative angular positions in relation to the axis of the socket, the rotary part of the engaging movement bringing them into angular alignment, in that means (52, 53) are provided firstly to hold the arm (51) immobile in relation to the insulating block (28) and to free it substantially at the end of the relative rotary movement of the plug (11) in relation to the socket (10), which then allows it to pivot around the corresponding tube (29) in order to effect the sharp coupling of the two contact studs (45 and 55) under the effect of the partial liberation of the energy accumulated by an elastic means (50) during said relative rotary movement, whereas during the reverse rotary movement allowing the separation of the plug (11) and the socket (10), the contact stud (45) carried by the arm (51) moves away from the corresponding contact stud (55), the remainder of the energy accumulated by the elastic means (50) ensuring that the brake is effected sharply, and in that lastly, towards the end of this reverse rotary movement, a stop (44b) causes the arm (51) to return to its initial immobile position in relation to the insulating block (28).

2. A plug and socket assembly as in Claim 1, characterised in that the elastic means acting on the arm (51) is a helical spring (50) surrounding the base of the tube (29) of the corresponding socket pin (31) and of which one of the end legs (50a) extend towards the periphery of the body of the socket (10) to engage permanently in a slot (44) parallel with the axis of the device and formed by two stop ribs (44a, 44b) projecting towards the inside on the wall of said body of the socket (10), whereas the other end leg (50b) extends firstly parallel with the arm (51) and is then bent at a right angle to run parallel with the axis of the device and engage in corresponding drillings in the end of the arm (51).

3. A plug and socket assembly as in Claim 2, characterised in that the means designed to cooperate to hold the arm (51) immobile in relation to the insulating block (28) during the rotary movement of said block driven by the pins (17) of the plug (11) during the engagement operation are constituted by the end (52) of the angled leg (50b) of the spring (50) and by a tooth (53) formed on a catch (49) which is coaxial with the insulating block (28) and free to rotate and follows the rotary movement of said insulating block (28) by virtue of a separating spring (58) disposed between a bearing point on the block (28) and a bearing point on the catch (49), whereas a stop (56) secured rigidly to the body of the socket (10) is designed to retain the catch (49) towards the end of the rotary movement while the insulating block (28) is allowed to continue its movement compressing the separating spring (58), which results in the end (52) of the bent leg (50b) being released from the tooth (53).

4. A plug and socket assembly as in Claim 3, characterised in that the stop designed to return the arm (51) to its immobile position at the end of the rotary movement preceding the separation of the plug (11) and the socket (10) is formed by one (44b) of the ribs bounding the slot (44) which holds the end of the straight leg of the spring (50) of the arm (51) captive, whereas as a sliding ramp (43) formed on the catch (49) guides the end (52) of the bent leg of the spring (50) up to the tooth (53).

5. A plug and socket assembly as in any one of claims 1 to 4, characterised in that for at least one of the holes a boss (57) projecting on the inside from the wall of the body of the socket (10) level with the end of the arm (51) prevents rotation of the insulating block (28) towards the engagement position after disconection as long as the arm (51) is not returned to its catching position.

6. A plug and socket assembly as in any one of claims 1 to 5, characterised in that in the position in which the plug (11) and the socket (10) are separated, a latch (41) disposed in a housing (41 a) in the bottom of the body of the socket engages, through the action of a spring (41b) moving it upwards, in a drilling (39) in a plate (37) fixed to the lower face of the insulating block (28), said drilling (39) being located perpendicularly in line with one of the wells in said block, and in that the corresponding pin (31) of the socket comprises an extension (34) which expels the latch (41) when said pin (31) is itself pushed back by the corresponding plug pin (17).

7. A plug and socket assembly as in any one of claims 1 to 6, characterised in that in accordance with arrangements known per se, the plug (11) and the socket (10) are fitted with corresponding means (20 and 23) for immobilisation in relative rotary positions, said means cooperating automatically in the engagement position and necessitating an operation to unlock them.

8. A plug and socket assemby as in any one of claims 1 to 7, characterised in that the disposition of the diverse parts and stops is such that the end (52) of the bent leg (50b) of the spring (50) is released from the tooth (53) just before the maximum compression of the separating spring (58) marking the end of the rotational engagement movement.

9. A plug and socket assembly as in any one of claims 1 to 8, characterised in that the rotating insulating block (28) is engaged with the socket (10) by means of corresponding threads (28a, 14a) carried by each element which form a rotation bearing for the block in the socket.

10. A plug and socket assembly as in any one of claims 1 to 9, characterised in that when the plug (11) and the socket (10) are not engaged, the difference in level between the contact studs (45 and 55) to be connected in relation to the supposed vertical axis of the device is greater than the diameter of these contact studs.

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