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Out of the box protection

Don't feel 'boxed in' when you are trying to safeguarding machinery within your corrugated packaging plant, Underwoods and Fortress can design a trapped key interlocking system that mitigates the inherent rsisk associated with the production of cardboard boxes. 

Cardboard Manufacturing Process

Almost any product that is manufactured will be packaged and shipped in a cardboard box. However, cardboard boxes are typically manufactured as foldable corrugated sheets in specialist corrugated packaging plants as the process for making corrugated packaging is fairly complex. Corrugated sheets are formed from flutes of recycled paper, the wavy pieces of cardboard, that are held between an outer layer and an inner layer. To create the fluting effect, rolls of paper are fed into a corrugated roller machine before being stuck together to create the corrugated sheets.

From here, the fluting is fed into a corrugator, whereby hot steam is sprayed on the material as it travels through the machine and glued to the two liners to obtain single, double or triple corrugated cardboard. The cardboard is then sent to the 'dry-end' of the machine which is made up of a slitter-scorer, cutter and stacker. This part of the machine is where the cardboard is cut into the required dimensions of the final corrugated sheets with a circular saw before they are stacked into shippable bundles. 

The corrugator machine can span the length of a corrugated packaging plant and has multiple sections which each perform a specific function. This machinery is susceptible to blockages and paper jams etc. As these machines pose inherent safety risks to operating personnel; one of the most cost effective ways to safeguard personnel entering the machine is by installing a trapped key interlocking system

Safeguarding the process

Thanks to the modularity of the mGard range, the trapped key interlocking system can be constructed so that only the section that requires maintenance can enter a safe state of operation, without having to shut down the entire production line. 

Ensuring a safe sequence of operation

One of the most dangerous sections of the corrugator is the 'dry-end' area whereby personnel are entering the machine for maintenance purposes. Therefore, the trapped key system prevents access until the equipment has entered a safe state of operation. 

To gain access into the dry-end area, an operator starts the process by turning the 'Power Isolation Key' from the key switch that is mounted in the machine's control cabinet. This breaks the machine's control circuits which powers down the dry-end of the corrugator.

At this point the 'Isolation Key' can be removed and inserted in the Key Exchange module to start the key transfer sequence. Upon trapping the 'Isolation Key', all 'Access Keys' can now be removed from the key exchange unit to gain access into the various access points within the corrugator dry area. This system permits multiple personnel to gain safe access into sub-sections of the corrugator at any one time. To gain access into any of the guarded areas around the perimeter of the corrugator's dry-end, the mechanical door locks must be unlocked using the 'Access Keys' that were removed during the key transfer sequence.

The 'Access Keys' must be inserted into the 'Primary Lock' on the mechanical door module in order for the 'Safety Key' to be removed before the actuator, that is holding the door closed, can be disengaged from the interlocks 'head' mechanism.

The Safety Key should remain on the operators person while they work inside the machine in order to safeguard against unexpected machine restart. Removal of the 'Safety Key' subsequentially traps the 'Access Key' in the door interlock, preventing the sequence from being reset until the 'Safety Key' has been returned to its corresponding lock and the door has been locked closed by reattaching the actuator to the mechanical door module. All 'Access Keys' must be re-inserted into the Key Exchange module before the 'Isolation Key' can be removed in order to recommence the machines normal operation.  

Unsure on Safety?

Are you currently working on a machiney safety project and are unsure of the best way of safeguarding your machine? 

We can help you to specify the appropriate safety device based upon your application. 

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