Our Products

We work to ensure everyone,
everywhere is safe at work

Our interlocking components are designed to be robust, durable and are proven in all types of operating environments that meet the demands of the harsh locations our customers operate in. Above all, they are designed to protect personnel where the risk of injury and damage are high.


The historical industry range of STI. Designed decades ago when the company was called Société d’Etudes et Réalisation de Verrouillage”; these constantly updated products are meant to resist to the most difficult conditions and environment. Initially designed for the Industry sector (steel, cement, construction material factories etc), it has been widely used by the rail sector as well as some heavy-duty energy applications. Based on the trapped key interlocking principle, SERV includes isolation locks, access locks and transfer boxes to fit any application and safety sequence. The SERV range is highly modular and adaptable with mechanical and electro-mechanical locks.

STI SERV product range


When Serv Trayvou & HF Sécurité merged, The Hercule range was incorporated into STI portfolio as a perfect addition to the SERV range. Hercule products are smaller and ligther but still fitted to many applications, especially in the Energy sector where the switchgear industry made it a standard for safety. Integrated into breakers, disconnectors, earthing systems or transformers, both key systems (flat key or Profalux keys) bring safety in cabinet to another level with millions of unique key codes.

STI Hercule product range

Access locks

Our access interlocks are used to reduce risk when workers enter hazardous areas. Their purpose is to eliminate the possibility of energy restoration occurring while someone is near a machine. They achieve this by trapping a key that controls the electrical supply.

These products are typically made up of two parts; a main body and an actuator or latch. The main body will attach to the machine, and the actuator or latch will attach to a door or gate. When these two parts of the lock are separated (i.e. when someone is in the hazardous area) the key is trapped. It is only released when the actuator or latch re-engages with the main body, at which point the machine can be restarted but the person is out of the hazardous area.

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To make areas safe during maintenance operations, hazardous energy must be isolated. ‘Exchange’ refers to a process whereby people are denied access to an area until it is safe (no hazardous energy is on). Our key exchange units are designed for this specific purpose; they only release access keys once isolation has been achieved, and only release isolation keys once access keys have been returned. This means that there is no room for human error, and people are only operating in environments that are safe.

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Isolation locks

There are many safety risks associated with modern machinery. These include mechanical, electrical, hydraulic, or pneumatic energy sources that, if not properly managed, could put workers in serious danger. One of the best ways you can mitigate these risks so no one gets hurt is through isolation. Isolation involves disconnecting energy sources from a machine so that it is safe to work with. Isolation can be achieved using our isolation locks; bolt interlocks, solenoid switches, and valve interlocks. Once mounted onto your equipment, they will ensure energy statuses are always correct. This is done through meachnical locking of machine command and power swicth offs. With the risk of human error eliminated, people who work with modern machinery are safe.

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Keys & accessories

Every business working environment is different-whether it’s the physical buildings, automation levels, control systems, or even safety procedures, not every site is going to be the same.

STI’s accessories make it easy to customize the interlocks at each site. We offer different types of keys, latches, padlocks, and switches which ensure that individual requirements are met. This helps you avoid the logistical nightmare of different interlocks at different sites.

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Logistics Solutions

With Salvo loading safety systems, drive-aways are impossible.

Salvo is specifically designed to improve safety at the loading dock. It works by locking a trailer’s brakes until loading/unloading is complete.

By forcing the operator/driver to carry out a set of actions before loading can begin or end, the risk of a dangerous situation occurring due to human error is eliminated. Plus, the risk of damage to equipment and inventory is minimized, and efficiency is maximized.

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Smart Key Manager (SKM)

While machinery and expert equipment are essential in any factory, they can also be dangerous if not properly managed. Ensuring that only authorized employees have access to critical areas is vital to safety, as well as smooth operations.

With STI’s Smart Key Manager, you can track and record key movement, and restrict key access. This gives you greater oversight and control over who is using what, when, and for how long. It also saves time and reduces costs by eradicating the need to track keys manually.

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Specials & Design

At STI, experience has taught us just how important customizable products are to our customers. No one site is the same, which means flexibility is crucial if our solutions are actually going to be solutions.

Whatever the challenge, our R&D team (with support from Halma) will come up with an innovative solution that puts safety and customer satisfaction at the heart of the development.

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