Plug assembly, in particular for a cooling container

Abstract

A multi-pole plug assembly, in which the positions of a first contact element and a second contact element can be exchanged by means of a turning device is disclosed. The first and second contact elements can be different in terms of their plugging compatibility, for example, in that they are configured as contact pins of different diameters. In addition or alternatively, the first contact element can be connected to an outer conductor, and the second contact element can be connected to a protective conductor or a neutral conductor. The plug assembly can be embodied as a four-pole plug and configured in such a way that the first and second contact pins can adopt the positions 3.sup.h and 6.sup.h (or vice versa) in relation to a distinctive nose. Within the scope of DIN Standard EN 60309-2, two electrically similar configurations can be realized in this way.

Claims

1. A multi-pole plug assembly, comprising: at least three contact elements, each contact element constructed as a contact pin; a turning device, on which a first one of the contact elements and a second one of the contact elements are arranged such that positions of the first and second contact elements are exchangeable in relation to a third one of the contact elements and the first contact element is connected to an outer conductor and the second contact element is connected to a protective conductor or a neutral conductor, said first and second contact elements having different diameters and being configured differently in terms of their plug compatibility; and a distinctive structure disposed on the plug assembly and configured to engage with a uniqueness groove of a complementary plug assembly only in a predefined relative rotational position, when the first contact element is positioned at a 3 o'clock position and the second contact element is positioned at a 6 o'clock position, or vice versa, when viewed in the direction of the complementary plug assembly, wherein configurations resulting through exchange of the first contact element and the second contact element (PE) enable a safe operation of the plug assembly in connection with a plug assembly according to the standard DIN EN 60309-2.

2. The multi-pole plug assembly of claim 1, configured with respect to the positions and/or shapes of the contact elements according to standard DIN EN 60309-2.

3. The multi-pole plug assembly of claim 1, configured for fixed connection to a device, in particular to a cooling unit.

4. A cooling unit, in particular in combination with a mobile refrigerated container, said cooling comprising a plug assembly comprising at least three contact elements, each contact element constructed as a contact pin, and a turning device, on which a first one of the contact elements and a second one of the contact elements are arranged such that positions of the first and second contact elements are exchangeable in relation to a third one of the contact elements and the first contact element is connected to an outer conductor and the second contact element is connected to a protective conductor or a neutral conductor, said first and second contact elements being configured differently in terms of their plug compatibility; and a distinctive structure disposed on the plug assembly and configured to engage with a uniqueness groove of a complementary plug assembly only in a predefined relative rotational position, when the first contact element is positioned at a 3 o'clock position and the second contact element is positioned at a 6 o'clock position, or vice versa, when viewed in the direction of the complementary plug assembly, wherein configurations resulting through exchange of the first contact element and the second contact element PE) enable a safe operation of the plug assembly in connection with a plug assembly according to the standard DIN EN 60309-2.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) In the following, the invention is described in greater detail with the aid of the figures with reference to an exemplary embodiment. It is shown in:

(2) FIG. 1 a section of a table of associations between protective conductor positions and electrical operating parameters according to standard DIN EN 60309-2;

(3) FIG. 2 a perspective view of a plug according to the invention with the protective conductor-contact element in 3.sup.h position;

(4) FIG. 3 the plug with the protective conductor contact element in the 6.sup.h position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(5) FIG. 1 reflects a simplified tabular overview of a part of the regulation content of standard DIN EN 60309-2. The table contains the associations specified in the standard between the clock positions of the protective conductor contact sleeve and the associated operating parameters of sockets, with the uniqueness groove by definition being at the 6.sup.h position at all times. The clock positions of the complementary plugs, which are of primary interest here, are mirror images thereof. Not shown in the table are the definitions of color codes that are used to easily distinguish voltage ranges (e.g. red for 380V-480V, black for 500V-1000V etc.).

(6) The specifications for four-pole plug assemblies (three phase conductors p and one protective conductor) can be found in the bottom ten lines of the table. Two of these are of particular interest for the present example a use in cooling containers and therefore are illustrated graphically next to the table: Variant A: Protective conductor at 6.sup.h: operation at 380-415 Volt, 50 or 60 Hz; Variant B: Protective conductor at 3.sup.h: Operation at 380 V, 50 Hz or 440 Volt, 60 Hz.

(7) Conventional cooling containers have a standardized, 4-pole 32 A-plug connection, which is unchangeably set to 3.sup.h (variant B in FIG. 1). Sockets from 16 to 32 A are permitted for this clock position and are either connected to 380V at 50 Hz or to 440V at 60 Hz.

(8) Since cooling containers are becoming more widespread worldwide, it oftentimes happens that the end customer has only installed a standard socket 32 A/4-pole/6.sup.h (variant A in FIG. 1). This socket is (with the same color code: red) connected to 380-415V. The cooling containers could easily be connected there, when the clock position of the plug would fit. Since cooling containers contain perishable goods, a fast solution is required which in practice often involves to simply cut off the distinctive nose of the plug. This overrides the mechanical clock coding and the plug can be inserted into the existing standard socket. In view of the absent distinctive nose, its operating permit is, however, rescinded, and the container plug must be replaced. Moreover, there is acute risk because the faulty plug can now be inserted in all sockets of suitable size and number of poles, which, for example, have the clock position 5.sup.h voltages of 600 to 690V, for which normally the clearance and creepage distance of a 3.sup.h plug are not designed.

(9) A simple solution of the described problem is realized with a plug assembly, in which the position of the protective conductor contact element can be exchanged with that of an outer conductor contact element.

(10) In this context, so-called phase reverser plugs according to DIN EN 60309-2 should be reminded of, which swap the position of two adjacent phase pins by mechanical rotation so as to change the rotation direction of the rotating field. Since the rotor or the turning device, which implements the pin swap, can be actuated from outside, no rewiring of the plug is necessary. The turning device also has mechanical end positions; but even without these a plug could not be inserted into a socket, when the pins are not appropriately positioned to the contact sleeves.

(11) An plug according to the invention for solving the afore-described cooling container problem is now being built such that a clock changei.e. the change in position of the protective conductor contact pin (PE pin) with an outer conductor contact pin (PH pin)establishes a modified plug having a mating face which can only be inserted into a socket that has a voltage and frequency which does not significantly differ from the socket with the original clock position. Such an electric resemblance is encountered between the 3.sup.h and 6.sup.h clock position of the variants A and B of FIG. 1, which in addition have the same color code.

(12) FIG. 2 shows by way of a perspective view a plug 100 according to the afore-explained concept. The plug 100 includes a casing 101 with a collar 102 in surrounding relation to four contact pins K1, K2, K3 and PE. A first of these contact pins, K1, is arranged together with a second contact pin, PE, on a turning device 110 (rotor). The first contact pin K1 and the pins K2, K3 are each internally connected to an outer conductor (not shown), the contact pin PE of slightly thicker diameter to a protective conductor (not shown).

(13) In FIG. 2, the protective conductor contact pin PE assumes the 3.sup.h position. In contrast thereto, FIG. 3 shows the plug 100 after a rotation of the turning device 110, so that the protective conductor contact pin PE has swapped its position with the first contact pin K1 and is now in the 6.sup.h position. It should be noted in this context that the clock positions are defined correct in clock time for the plug openings of the sockets; when looking at the pins of a plug, the clock positions are therefore reversed.

(14) Advantageously, the rotation direction of the electric field does not change as a result of the position change of the contact pins K1 and PE, so that the running direction of connected motors is maintained.

(15) To carry current and voltage, a plug must be plugged into a socket. On the other hand, a contact pin exchange in the plug may only be made in a de-energized state. Such an exchange is therefore possible by design only in the non-plugged state, because of the need to actuate the internal rotor 110 (rotated by 180) with the help of a screwdriver. For this purpose, the screwdriver blade is placed in the slot 111 of the movable nose of the rotor 110. By putting pressure on the nose, it bends elastically inwards, thereby mechanically unlocking the rotor, which can then be rotated by 180 in the specified direction. As the screwdriver pressure is removed, the nose springs back and locks the position of the rotor again mechanically in the other end position. There is no need to seek for the correct position of the rotor, but is established automatically and intuitively by mechanical end stops. Details of the described mechanism of actuation by a rotatable and lockable rotor can be found, for example, in EP 841 726 A2.

(16) The described configuration of the plug 100 allows a technical layman the secure connection of a typical container plug (with the special 3.sup.h clock position) to a widespread standard socket (in 6.sup.h clock position), without implementing any plug combinationdangerous for life and limbas a result of an irreversible damage to the plug.

(17) Regardless of the example shown in greater detail above, the exchange of different contact elements can also be used in other applications. In general, the invention relates to a multi-pole plug assembly, in which a turning device, enables an exchange of the positions of a first contact element and a second contact element. The first and the second contact elements may be different in terms of their plug compatibility, for example, by being realized as contact pins of different diameters. In addition or as an alternative, the first contact element can be connected to an outer conductor and the second contact element to a protective conductor.