The invention belongs to the field of a protective mechanism designed to be used when inserting a detachable module into a base part of a surge protective device, more precisely to the field of a mechanism that prevents insertion of a detachable module into a wrong base part of a surge protective device according to voltage of devices for electronic surge protection.

Technical Problem The technical problem solved by the present invention is a constructional solution to a mechanically coded mechanism designed to prevent a false insertion of a detachable module into a base part of a surge protective device subject to voltage. A wrong combination of voltage of a module and that of a base part of a surge protective device can result in material damage, even more; it can be hazardous for a fitter of surge protective devices. A requirement for coding and preventing a wrong installation of a detachable module is defined by standard IEC 61643-11 (7.3.1).

A mechanically coded mechanism must allow a simple installation of various combinations or codes for detachable modules with different prescribed voltages.

Prior Art

An analysis of the prior art shows that a majority of manufacturers of surge protective devices keep to the concept of pins that are arranged vertically with respect to a receiving pin in a base part of a surge protective device.

DE000010001667C1 discloses a way how individual modules are coded according to voltage and how receiving sites in a base part are coded accordingly. The bottom side of the module is provided with a specifically shaped pin that is rotatable in its centre according to a voltage of the module, thus allowing different variants of the product. The pin which is also inserted into the base part must be oriented in a way to match the orientation of the pin in the module. If this is not the case, a mismatch of the pins occurs when the module is inserted into the base part, and both a further insertion of the module and a contact between the pins of the module and the base part are prevented. The system of coding must always ensure that first a contact of the pins for coding is established when the module is inserted into the base part and only then a contact between the metal pins of the module and the base part is established, through which pins the electric current flows.

A concept of a horizontal placement of pins is disclosed in patent DE3639533A1 . However, the patent does not offer a solution to the problem of inserting a module with a wrong voltage. In fact, the present solution is adapted to the concept of horizontally arranged pins that transfer electric current through the surge protective device, but it is further provided with a protective element that prevents a module of a wrong voltage from being inserted.

Solution to the Technical Problem

The essence of the mechanically coded mechanism designed to prevent a false insertion of a detachable module into a base part of a surge protective device according to voltage lies in that the bottom of the base part intended for the arrangement of the detachable module is provided with vertical grooves, into which a coded combination of first pins is arranged according to the voltage, for which the detachable module is embodied. The housing of the detachable module [Nijis provided with grooves in the same verticals intended for the arrangement of a coded combination of second pins arranged on positions, in which there are no first pins in the base part.

The mechanically coded mechanism designed to prevent a false insertion of a detachable module into a base part of a surge protective device according to voltage will be described in more detail in the continuation by way of drawings representing in:

Figure 1 - base part and module

Figure 2 - top view of the base part and module

Figure 3 - first pin

Figure 4 - second pin

The mechanically coded mechanism of the invention designed to prevent a false insertion of a detachable module into a base part of a surge protective device according to voltage is embodied as follows: a bottom 1 of the base part is provided with a groove 15 in the centre, said groove 15 having grooves 1 1 , 12 at one side and inversely from the groove 15 a groove 16 having grooves 1 1 ', 12' at one side and grooves 13' and 14' at the other. Pins 25 and 26 of a module 2 are arranged into the grooves 15 and 16. The housing of the module 2 is provided at its lower part with short grooves 21 , 22 having grooves 21 ', 22' at the opposite side. To the right of the pin 25 there are arranged grooves 23, 24 and to the right of the pin 26 there are arranged groves 23', 24'. The coding of the mechanism is carried out by a combination of grooves 1 1 , 12, 1 ', 12', 13, 14, 13', 14' of the bottom 1 , into which grooves first pins 3 are arranged, and free grooves. A combination of free and full grooves 21 , 22, 21 ', 22', 23, 24, 23', 24' of the module 2 is inverse to the combination of the full and free grooves in the bottom 1 . For modules 2 having a certain voltage, various combinations of full and free grooves of the bottom 1, and the module 2 are made. When the module 2 is inserted into the bottom 1 , the pins 25 and 26 cannot slide on the grooves 15 and 16 due to the pins 4 in the grooves of the module 2 that collide with the pins 3 which fill the space of the grooves of the bottom 1 . In this way, a module having an adequate voltage has the pins arranged in a way to pass by the pins in the base part, they do not collide. If a voltage of a module is inadequate for a certain base part, the pins of the insertable module frontally hit on the pins of the base part and block a further movement of the module 2. This happens at a height that prevents both a mechanical and electric contact of the pins of the module and the receiving pins of the base part. The coding with pins is performed on the module 2 and the base part 1 in a way that the module can be inserted into the base part by being rotated by 0° and 180°. Due to a limited number of pin combinations modules with higher voltage are allowed to be inserted into base parts with lower voltage.