Door Industry Journal - Spring 2014

Also online at: www.dijonline.co.uk 72 THE door industry journal spring 2014 powered gates THE MYTH OF THE SELF-LOCKING GATE MOTOR Do you know the difference between a reversible (‘non-locking’) gate motor and an irreversible (‘locking’) gate motor? Well, don’t be too concerned if you don’t know because Simon Van Lessen from Linkcare Gate Automation explains the difference in the following article. The first (non-locking) allows an automatic gate to be pushed open or closed by hand in the event of an emergency when there is no power. The second (locking) usually features some physical mechanism to prevent this from happening. This could be a hydraulic non-return valve or the way the motor and gears are connected. However, it is possible with enough effort, to force a ‘locking’ gate motor, but you will break something in the process. Most manufacturers will recommend additional locking for any leaf greater than 2.5m wide. This is to protect the mechanism and not the entrance. This is why you will often find ‘locking’ and ‘non-locking’ versions of the same motor specified for different length leaves. You must understand that the leverage that even a small child can exert on a long leaf is immense. As the mathematician Archimedes is said to have commented on the lever, ‘Give me a place to stand on, and with a lever I will move the Earth.’ I have seen with my own eyes the 10mm thick steel brackets holding a motor on a 4m five-bar gate (which did not have a lock to hold it shut) being bent by a 9 year old pushing at the opening end. So if reversible gate motors and even ‘locking’ gate motors do not lock a gate shut, what’s the point of having them? Where is the security they’re supposed to offer? Where is the resistance to winds, falling objects or children pushing against them? The answer is simple and not expensive. It’s also the recommended additional security for any gate over 2.5m in width. Fit an additional lock! It’s that simple. Traditionally, reversible motors have been used for applications that include a requirement for opening in the event of a fire without power. In this situation, if the power fails, a Mag Lock will release and the gates can be pushed open. This design has been superseded by the advent of 24V systems which can be backed up easily by batteries and allow a gate to be powered open in the event of a fire. Mag Locks are generally simple to fit and allow for a certain amount of play in a gate. It is enough that the lock and plate meet face to face for it to hold the gate locked, although you must remember that if the power to the lock fails it will release. For more secure applications, an electromechanical lock can be used, which will remain locked in the event of a power fail, and can be unlocked using a normal manual key. These come in a wide variety that can be fitted to lock a gate leaf to the ground, to a post or to lock two leaves together. Where serious locking is required you can move on to motor driven bolts which have a bar 30mm thick with a ‘throw’ of 150mm which can go into the ground, a post or again can lock two leaves together. If security is the prime concern, it is important that the gate itself should be adequately fitted, as there is little to be gained by fitting a secure lock if the gate can lifted or broken from its hinges. So don’t be fooled by the promise of ‘locking’ gate motors – they don’t exist. If you want to provide your customers with genuinely locking gates that lock shut at the end of their closing cycle and are released when their opening cycle starts, simply fit a lock. For more information visit www.linkcare.net Linkcare Electromagnetic waterproof mag lock Nice PLA11 Electro-mechanical lever lock