Automatic Swing Gates in Aberdeen, Scotland, Aprimatic, BFT, Beninca, CAME, Ditec, FAAC, Nice: Centurion Security

Inward or Outward, One Leaf or Two?

Swing gates can comprise either one gate leaf or two, and can be automated on either basis.  Swing gates can also open inward or inward, depending on the location, terrain and other factors

The majority of swing automatic gate systems tend to be inward-opening twin-leaf.  Twin-leaf systems have the effect of halving the area into which each gate leaf opens, thereby limiting intrusion  and generally speeds up the operation of the system. 

Outward-opening swing gate systems are generally installed where the road or driveway inclines, sometimes quite steeply, toward the property.  By opening outward little modification in gate design is required, but consideration has to be given to the gate approach, access control and certain safety aspects.

However, under certain circumstances, inward swinging gates can be designed to navigate "up the hill" by means of special hinge arrangements, known as "kicking hinges" or "rising hinges".  Such systems can be installed where outward swinging gates are neither practical nor desirable.

Types of Swing Gate Systems

Swing gates can be powered by essentially three types of mechanisms:

  • Underground motors
  • Rams
  • Universal Arms (sometimes known as Articulated or Jointed Arms)

The latter two types of systems noted above are catgorised as "above ground" systems.  Underground motors are often referred to as "hidden" systems, since virtually nothing is visible above ground level.

Within the first two types above, the drive units can be hydraulic or electo-mechanical in design.  Some electro-mechanical systems operate at  240V AC, while others operate with high-efficiency low-voltage systems (typically 24V DC).  Universal arms are always electro-mechanical in design.

Underground Systems

In Centurion's experience these are by far the most popular types of systems, even though they tend to be more expensive to install than "above ground" systems. 

As a rule the equipment costs more because it is more complicated, plus it requires more time and skill, to install. 

The main reason why most of our customers choose underground systems is that they are "hidden" from view and therefore more aesthetically pleasing.

In particular, where a new set of gates are to be installed, the "hidden" motors do not detract in any way from the "look" of the gates.

However there other factors which can favour underground systems:

  • They generally do not require supporting steel posts
  • They can be fitted neatly against new or existing pillars
  • Due to their design they can open up to 180° - very useful in some driveways which "fan out" out behind the opening and where the gates might encroach on internal part of the driveway
  • When fitted to outward opening gates they do not have have "clumsy" motors on the outside, markedy detracting from the gate design.


The most common type of "above-ground" gate system is the ram.  This system usually requires steel posts on which to pivot and a vital operating geometry in order to work properly.  The opposite end of the gate ram is then attached to the inside of the gate leaf, and via an internal "push-pull" arrangement, the ram pulls the gate open and then pushes it shut.

While perhaps not as aesthetically-pleasing as underground system, rams can be very effective, lower-cost solutions.  The rams can also be located behind a feature on the inside of the gate make it less obvious when viewed from the outside.  Ideally rams should be fitted to the middle of each gate and post to optimise load and power distribution across the gate leaf.  However they can also be fitted at the top or bottom of the gate leaf, as required.

As a general rule rams are also more powerful drive units than either underground or articulated arm systems.  Thus when specific considerations are involved, such are higher leaf weight or width, high wind factors and some gate constructions, rams can be the preferred option.

Also where the gates require to have "kicking" or "rising" hinges in order to navigate up and down an inclining driveway, rams (particularly with inbuilt slowdown features) are not just the preferred option, but the only option.

Depending on other design or installation factors, typically a ram can open a gate leaf up to around 110° from it's closed position.

Universal Arms

Universal (Articulated or Jointed) Arms are designed to fit easily to most gates, posts or pillars. 

The mechanism is always electromechanical and comprises a motor attached to a caliper-like arm. Since the drive arrangement is hinged in three places, it provides a virtually universal method of fitting and operation.

Often, due to their relatively simple design, they require the least skill.  Like rams they can be fitted at any level on the gate leaf.  However care must be taken to ensure that nothing encroaches into the articulated mechanism during the automatic gate operation.

Depending on other design or installation factors, typically a universal arm can open a gate leaf up to around 130° from it's closed position.

Hydraulic or Electromechanical?

While engineers may well debate the merits of hydraulic over electromechanical gate systems or vice-versa, in practice, we at Centurion mainly install hydraulic gate systems.

Within a hydraulic underground system, an electric-powered pump feeds pressurised fluid to a hydraulic jack.  It is the jack which then does the work of powerfully opening and closing the gate. 

This is not dissimilar in concept to that of a car braking system.  When you press the brake pedal the degree of pressure has some bearing on the rate at which the car will stop, but it is not the brake pedal which stops the car -- it is the hydraulic system pumping fluid to a set of powerful brake disks and pads which actually stops the vehicle in an emergency.  Pressing the brake pedal with a relatively small amount of "leg" force transfers a massive amount of force to the braking system itself.

In an underground electromechanical system, it is the electric motor which does all the work of opening and closing the gate leaf.  Consequently, with some systems there is a higher degree of electric motor "burnout" over the years.  However electromechanical technology has continued to improve in all fields of engineering, and as result such systems are worthy of consideration. 

Hydraulic rams generally operate on a piston-like arrangement.  An electric pump "pushes and pulls" the piston back an forth, thereby opening or closing the gate mechanism.  Again the transfer of electrical to hydraulic power produces considerably greater force within the ram itself.

By contrast many electromechanical ram systems have a wormdrive (sometimes known as a screwdrive) mechanism.. This is simply powered by an electric motor which winds and rewinds the worm or screw to open or close the gate leaf.  As a general rule electromechanical rams systems tend to designed for lightweight, lower-cost gates 

Overall electromechanical systems are cheaper than hydraulic systems, both in terms of material and installation costs.  

It is our practice at Centurion to provide honest appraisals of different systems when providing advice and quotations.  While we always advise as to which system we believe, based on our experience, would be the best for a given installation, we regularly provide our customers several alternative options and quotations, in order that they can make informed decisions that covers their security/automation requirements, their individual preferences and, of course, their budgets.

Commercial and Domestic Applications

Centurion Swing Gate systems are suitable for both commercial and domestic installations. 

Our swing gate systems can easily power gate leaves up to 7 metres wide and around 3 metres high, although most typical swing gate leaves tend to be in the region of 1.5 metres to 2.5 metres wide and around 1.2 metres to 2 metres high.

Our installations can cover from occasional use, through regular use to intensive use.

Thus our swing gate systems are suitable for applications from low-use domestic driveway use to intensive situations such as city-centre flat developments and busy country estates.


Click below to download a Centurion Swing Gate Specification Sheet (PDF):

 PDF.image  Download ZT44 Electro-Hydraulic Ram System PDF


 Download ZT40 Heavy Duty Electro-Hydraulic Ram System PDF

 PDF.image  Download ZT70/71/72 Electro-Hydraulic Underground System PDF
 PDF.image  Download EM73 Electro-Mechanical Underground System PDF