© 2007 Door & Access Systems
Publish Date: Spring 2007
Author: Bill McCoy
Pages 66-67

The ABCs of Gate Operators
Gate Operators Open Profitable New Opportunities
By Bill McCoy

Installing and servicing the automated operators used to open and close vehicular access gates is a good way to improve your profit margin and give your customers a whole new level of service and convenience.

Gate operators deliver healthy margins, so installing them yourself rather than sub-contracting the work can make your job more profitable. The dealer price on a gate operator can range from about $500 for a basic unit to handle light traffic to more than $5,000 for a continuous-duty operator that can handle the heaviest gates and demanding traffic patterns. Offering a maintenance agreement can improve your cash flow and your customers’ peace of mind, because regular service checks and maintenance can help prevent problems.

Whether your customer is a homeowner, a gated community, a busy condominium or apartment building, or a commercial, industrial, or manufacturing facility, there is a gate operator designed for the job.

Choosing the Right Operator
The majority of gates fall into three categories: swing gates, slide gates, and barrier arms. Each type of gate requires a specific type of gate operator with a particular rating, from light duty to continuous heavy duty. The size and weight of the gate, along with the maximum number of times the gate needs to open and close per hour, determine the duty rating you need.

Residential and public access applications tend to favor single or double swinging gates; in commercial and high-security applications, sliding gates are more common. Barrier arm gates are used primarily in parking applications because they raise and lower faster than swing or slide gates can open and close, and because they prevent cars from “tailgating”—sneaking in by following the car ahead too closely.

It’s important to recommend both the proper type of operator and the right duty rating for the job and conditions. Using the wrong gate operator can result in a malfunctioning or downright dangerous system. Generally, operators that use worm gear reduction systems stand up to severe usage and tough operating conditions much better than belt-reduced operators. Continuous-duty motors are best suited to high-cycle applications.

Go to the Source
If you’re not sure which operator is right for a specific job or have questions about the installation or operation, manufacturers are a wealth of valuable information. Your manufacturer should be able to recommend the right operator for the job and provide you with detailed blueprints and technical specifications.

Take time to go over them, and get comfortable with the operator and all the working parts. If you have any questions, get them answered before you head out. You’ll save valuable time on the job and create a great impression with your customer, too.

Today’s sophisticated gate operators offer smooth, ultra-quiet performance, anti-theft devices, battery backup, controls that close the gate automatically after a set interval, optional solar panels for remote installations, and a wide range of safety devices and accessories. Most operators use electronic control boards that integrate functions and make for simplified installation and greater flexibility.

Gate operators are compatible with a wide variety of entry-control devices, from telephone entry systems to radio controls used with garage door openers and card-reader systems.

Swing Gates
Swing gates can be operated by either a harmonic arm or a linear actuator. Linear actuators are the most popular choice for residential gates weighing less than 600 pounds because the arm is connected directly to the gate on one side and a fencepost on the other. Because the operator doesn’t sit on the ground, you don’t have to pour a concrete pad, and the operator is less visible.

A linear actuator moves in a straight line back and forth; when it retracts, it pulls the gate open, and when it extends, it pushes the gate shut. If you’re operating two gates, it can be a more economical choice because both arms can be operated from the same control panel.

Harmonic arm operators can handle heavier gates—up to 5,000 pounds. The harmonic arm is connected to the drive shaft and extends and breaks into two pieces that pivot together. When the shaft rotates clockwise or counterclockwise, the attached arm rotates as well. The hinged extension arm pulls the gate with it and collapses in.

The gate operator needs to be installed so the two sections of the arm don’t scissor over each other, creating the potential for dangerous accidents. The operator sits on the ground on a cement pad that needs to be 30 inches below ground level, or below the frost line in areas that get snow, to prevent frost heave.

Slide Gates
Slide gate operators may be operated by chain drive, cable drive, rack and pinion, or hydraulic drive. Chain drive is the most common, as it tends to be the least expensive. It consists of a chain connected on either side of the gate that runs around a sprocket with pulleys to hold it in place. As the motor turns the drive sprocket, it makes the chain go back and forth, thus pulling the gate back and forth.

Rolling slide gates have wheels that roll on a track or on the ground—an economical choice for areas where there is no worry about accumulating snow. Cantilevered gates, on the other hand, are suspended between four rollers, so the gate doesn’t contact the ground. The clearance allows the gate to operate with up to a foot of snow on the ground.

Slide gates are often the first choice when security is foremost. A swinging gate can sometimes be “bullied” into opening by pushing against it with a heavy piece of equipment, like a big truck, until the gears slip or strip. Because a slide gate is a single piece that retracts, it’s hard to force it open.

Safety First
Gates can range from a few hundred to many thousands of pounds. All that mass in motion can create a lot of force if the motion is stopped unexpectedly by an obstacle. If a gate bumps into a car, the result can be expensive damage. If it bumps into a person, the result can be deadly. In fact, before UL 325 safety guidelines went into effect in 2000, an average of four people lost their lives every year in accidents involving slide gates.

Although the safety guidelines are not yet mandated by law, as a professional installer you’ll want to be sure you’re in full compliance to protect both your customers and yourself. The guidelines mandate two forms of entrapment protection—one internal and one external—for any vehicular gate operator with general public access.

External safety devices depend on the class of gate, and can include contact sensors, non-contact sensors, constant-pressure controls, and warning alarms. Residential or commercial gates that provide vehicle access for the public should include a sensing edge or a photo eye that automatically stops or reverses the gate if the edge is struck or the beam is broken.

No vehicular access gate should ever be used for pedestrian access. Pedestrians should have a separate entry. In many locations, building codes require pedestrians to have a separate gate or entry point.

Getting Started
To help get you started, many manufacturers provide hands-on installation and maintenance training and installation manuals. Most manufacturers offer plenty of accessible information on their operators. Choosing a single manufacturer that provides operators, safety devices, and entry-control systems assures you that all your components will work together to get the job done right.

SIDEBAR

Swing and Slide Gate Operators
Light Traffic 10 cycles per hour
Normal Traffic 20 – 30 cycles per hour
High Traffic Over 30 cycles per hour

Barrier Gate Operators
Normal Traffic 25 cycles per hour
High Traffic 100 cycles per hour
Commercial Parking 250 – 300 cycles per hour

Bill McCoy is an instructor at the Chamberlain Training Academy in Tucson, Ariz. This article originally appeared in the November/December 2006 issue of Fencepost magazine. Fencepost is published by the American Fence Association.