Standard single and double track aluminum cantilever gates are excellent for your standard slide gate for residential and commercial properties. However, once openings get wider, gates get taller, additional wind load is added, a standard cantilever slide gate may not be enough. This is where box framed cantilever gates are necessary.
Box framed cantilever gates are much like two regular cantilever gates joined together 24” apart and held together by a series of square tubes and several diagonal trusses. This creates a very rigid overall framework to withstand higher weight or wind loads. Box framed cantilever gates are typically used for openings longer than 50’, when the height exceeds 8’, or when the gate infill material is solid, creating considerable wind load.
Box framed cantilever gates are very large and heavy by design in order to withstand the size and wind load requirements. Box framed cantilever gates are essentially two cantilever gates forming a box truss design, so these gates have different automated gate access control compared to a standard cantilever gate.
Before you can even begin installing any automated gate equipment on your box framed cantilever gate, you must first verify the box framed cantilever gate is functioning correctly. If it is not and you install a gate operator, it could damage the gate operator, the rollers and the track due to its considerable weight and girth. To determine if the gate is functioning correctly, it should be able to be opened and closed by a large adult manually with a reasonable amount of force.
This is specific to box framed cantilever gates because the extra weight of the gate is likely going to make the gate posts bow inward and cause excessive and premature wear on the rollers and tracks, and potentially even overload the gate operator. This may not be immediately noticeable, but if not prevented will occur over time.
To prevent this wear and tear, it is a good idea to install a brace over the top of the gate between the adjoining gate posts. This keeps the posts from bowing inward and creating extra stress on the gate equipment and operator.
Selecting an Operator
Due to the excessive length of a box framed cantilever gate and resulting extra weight, you cannot use a gate operator manufacturer’s standard charts to choose your box framed cantilever gate operator. These charts usually suggest your gate operator based on either the length of the cantilever gate or the cantilever gate’s weight. Since a box framed cantilever gate is technically composed of two cantilever gates, these charts may not select the best gate operator that is powerful enough to consistently move the gate.
At American Access Company, we suggest you multiply both the gate length and the gate weight by 1.5 when using these charts to choose an operator to support larger size. Once you do this, it’s likely you’ll find that there is a limited number of gate operator manufacturers that can accommodate a large box framed cantilever gate. These large gates typically require a 2-horsepower motor or hydraulic drive system.
While there were some discrepancies in how you determine which gate operator is right for your box framed cantilever gate compared to a standard cantilever gate, no such discrepancy applies for the location of the installed gate operator from the face of the gate. Whatever the guidelines are for the particular gate operator you choose, follow those exactly when installing your automated gate controls for your box framed cantilever gate.
One facet of automated gate controls you will have to adjust during installation is the obstruction sensitivity. For standard cantilever gates, the obstruction sensitivity is usually set high. However, a box framed cantilever gate is heavy and creates a lot of resistance. This will generally cause more pull on the operator which could easily trip the obstruction sensitivity. It is important to take more consideration when setting the obstruction sensitivity when installing the automated gate controls for your box framed cantilever gate.
Once your gate operator is set and working correctly, it’s imperative to take specific safety parameters into consideration. Box framed cantilever gates, by design, are 20” – 24” wide. The UL 325 provisions for providing contact and non-contact sensors don’t fit the parameters for box framed cantilever gates. Install additional photo eyes of sensors to account for the extra-wide gate profile to prevent run-ins with vehicles and to ensure pedestrian safety.
Box framed cantilever gates are very large and very heavy, and even after installation is complete and the gate is in operation it is imperative that there is continuous maintenance and inspections performed. This is to ensure there is no premature wear and tear on the gate operator, trucks or tracks.