Nowadays, in modern industrial plants, we realise how important it is to install mechanisms which prevent false movements which put workers and machinery in danger. This is absolutely necessary in electrical plants of high and low voltage.
Our solution consists in triggering a mechanical interlock between the different parts of equipment (as for example mechanical manoeuvres, command levers, column shift-bars, doors) by inserting a safety lock in the equipment. The structure of such blocks is specific and cannot be changed. The mechanism only works if a certain sequence is followed. By combining different types of devices, it is possible to set up locking devices in very complex plants so that will be avoided damages to property and accidents to operators.
This is the simplest type of device. It is used to gain access to premises in complete safety. In this situation it is necessary to use a lock from the SB series and a door blocking device from the SBP series. When the switch is in the closed position the key is blocked in the lock and the door is closed. In order to open the door, the switch must be moved into the open position then the key must be turned and taken out blocking now the lever. The same key is now used to open the door and to access to the premises.
The key cannot be taken out of the lock while the door is open.
It is therefore impossible for the operator to be exposed to an electrical current in the room while the door is open, so guaranteeing him the maximum protection.
This system is used where it is necessary to access to all the premises at the same time without incurring danger for the operator. For this system a safety lock SB11 is used together with four door locks SBP1 and a key exchange box type SD13 are needed. When the key is removed from the bolt lock of the switch and then inserted and turned in the exchange box, it becomes locked in so that is now possible to release the other three keys. Upon being extracted the keys can be inserted into the doors locks to open doors.
All the keys must be reinserted in the key exchange box to be able to release the blocked key and therefore switch on the current in the plant.