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Locking systems for large control cabinets

The basic rule for all control cabinets is that the components inside, especially the sensitive electronic components, must be protected. However, there are significant differences, especially in the locking systems used. When special customer requirements have to be met, standardised locking systems sometimes reach their limits. Here, customised locking systems offer the right solution.

 

Control cabinets are available in various shapes and designs, ranging from single cabinets to in-line cabinets or cabinets with double doors. All are available for indoor and outdoor applications. Environmental conditions and individual requirements significantly affect the choice of materials and the final design of the cabinet. But the cabinet alone does not adequately protect the internal components and electronics. The locking and hinge solution is much more critical if the cabinet door is meant to seal securely and, if necessary, must withstand high pressure or fulfil other safety requirements. In order to find the most suitable closure and hinge solution, the environmental influences and the installation location are also decisive. Whilst housings used outdoors are mostly made of plastic and powder-coated steel, the material of choice remains stainless steel for very special applications. The locking components should be made of the same material, regardless of material selection. Furthermore, high demands on tightness and the prevention of vandalism may have to be met in outdoor applications by using, for example, the IP65 protection class and security standards according to resistance classes.

As the world market leader of locking systems for housings and control cabinets, EMKA draws from a broad product range of different materials in order to use the appropriate materials for the locks, hinges, and seals for the prevailing conditions in each case and thus fulfils the requirements for strength, functionality and cost-effectiveness in the best possible way. In other words, there are around 1.2 million product variants in locking technology for housings.

Conventional locking systems with expansion stages

When designing control cabinets, a distinction is made between closures inside and outside the door seal. Locks inside the door seal are installed on interior doors and frequently outdoors. Here, for example, a swing handle is mounted on the door, which drives two locking bars inside the door – using either a drive or a locking cam. These systems compress the door seal and ensure a secure closure. EMKA has developed a unique compression latch system with multiple interlocking for closures inside the door seal. If using a rotating movement of a compression latch of only 90° –usually 180° – the door closes at several locking points. These locking points are flexible and can be placed on only one rod. The vertically distributed locking points can be extended to additional horizontal points with a specially developed corner deflection. The compression extends up to 18 mm with these innovative multi-locking systems compared to the standard stroke of 6 mm. This pulls the entire door evenly into the door‘s seal and thus ensures the door is firmly closed, even if the internal pressure is high. In addition, the compression latch function prevents the door from popping open and relieves the pressure.

If the lock is to be placed outside the seal so that, for example, no components protrude into the cabinet interior, the locking bars on the inside of the door are pushed into mounted locking points on the door frame with the door closed using a swinghandle or lifthandle. Bevelled notches on the locking bars provide the necessary contact pressure of the door. Here, too, a corner deflection can provide additional horizontal locking.

Electronic locking solutions

Furthermore, electronic locking solutions are increasingly in demand for conventional locking systems. Here, EMKA also offers a complete range of products, from electromechanical outdoor handles for active and passive housings to electronic control cabinet locks and highly innovative solutions for data centres that are totally wireless. For the highest security requirements with AES 256-bit encryption for access control up to control centre monitoring, EMKA developed the swinghandle Agent E. The smartphone or PC-based software products interlink the locking solutions into complete online access control systems.

The design of control cabinets demands the highest safety requirements for locking components. The specialist for locking systems for control cabinets designed an attractive swinghandle with resistance class RC2 for outdoor control cabinets for the Dutch IT system house ­Tecnolimit. This handle is easy to operate and can be monitored electronically. Furthermore, a card reader has been integrated so that the cabinet can only be opened by authorised persons using an RFID card. The handle thus protects and prevents unauthorised access. However, this example shows that the standardised lock is insufficient for special requirements. EMKA already offers many options for designing locks using its extensive modular product range. But sometimes standard components have to be adapted, or even customised solutions must be found. The design and development of these unique and individual solutions are one of EMKA’s core technical know-how. Appropriate solutions are developed in the company’s own technology centre in Wuppertal.

Hinges and seals as essential components of a system

However, the locks of a housing and its hinges and seals directly affect the cabinet’s stability, aesthetics, and functionality. The door’s position is the first criterion for choosing the right hinge, whether internal or surface-mounted. The weight, size, and material of the door and the opening angle are critical factors. The installation requirements, i.e. whether the hinge is to be screwed on or welded on, prominently, concealed or completely invisible, are further factors. There are various materials to choose from: plastic to zinc die-cast, steel and stainless steel to aluminium die-cast.

The seal between the door and the housing is also a critical component of the housing. Here, the environmental influences and tightness requirements set the decisive parameters for the proper selection. EMKA manufactures high-quality rubber profiles in its own production facilities. Elastomer seals for plug-in (groove, sheet metal) are ideal for sealing the gaps and compensating for manufacturing tolerances. Individual in design and adaptable to chemical damage because of material variants, they fulfil customer-specific properties and are replaceable in case of service.

Locking systems from a single source

It is advantageous if the entire locking system – i.e. locking type, hinge, and seal – is supplied from a single source. The customer has only one contact person to synchronise these crucial components with the housing design. For locking systems outside the seal, features such as the hinge and catch can then be selected so that the hole patterns are identical. Thus, the installation of the door is flexible and can be mounted with hinges on the left or right-hand side. In addition, the hardware components for locking systems outside the door seal must be designed to save space in terms of both depth and width in order to keep the bending area as small as possible. In other words, the clear width of the cabinet housing is increased.