Gate Operator Basics
Many times over the years, we have been asked, "Why do you use hydraulics instead of electro/mechanical systems to operate gates?"
Simply put, we use hydraulics because they are more reliable, more durable, self locking, easier to work on, faster, do more work and are cost effective over the span of the gate life.
Maintenance costs are substantially less because there are literally hundreds fewer parts in our equipment. When the time comes to service a gate operator, it needs to be user friendly. Our equipment is the type of equipment that any good mechanic can understand. No custom parts, and no printed circuits that must be specially ordered. Every component is easily understood and some are available off the local shelf of the industrial supply house. All of our moving parts are running in oil!
Hydraulic power is capable of tremendous amounts of work. The pumping power of a one-horsepower motor is smoothly transmitted through valves to hydraulic motors or a cylinder, avoiding gears, pulleys and belts. We are able to control very large or very heavy gates with our understanding and proven designs of hydraulic systems. We enjoy the same awesome power employed in the machines that tunnel through mountains and build the nations' highways. Our hydraulic operators are not limited to part-time duty, where you need to count the operations per hour, but can keep the largest of gates moving at a fast pace as many times as you desire. Ours are truly industrial grade gate operators!
We also feel very strongly that a security gate should be secure. Parts that are easily defeated by the use of simple hand tools compromise many security gates. All of our operators are designed to be self-locking. Far more than simple tools would be necessary to breach a gate powered by HySecurity Gate Operators.
Our operators are priced competitively with some of the other good machines in the market, but our operators will do so much more.
When only the best will do, specify HySecurity Gate Operators. We will back you up all the way with our engineering expertise and our service because we are the best!
Whenever you hear someone talking about the performance of gate operators, the conversation usually revolves around a discussion of how much a gate weighs, whether or not it is a cantilever design or how many cycles per hour it is going to operate. These kinds of conversations, while entertaining, do not contribute a great deal to the analysis of operator performance.
Sliding gate operators, by their nature, exert a horizontal force on a gate panel that is carried on a set of rollers or wheels, and by the application of that force, cause the gate panel to move. This force is called drawbar pull and it is measured in pounds. Just how easy or difficult the gate is to move will determine how powerful the operator must be. We have all experienced having to push an automobile that has run out of gas. Assuming your experience took place on flat pavement, you were probably able to push the car to the side of the road or maybe to the end of the block. Chances are that the car weighed three or four thousand pounds but you were able to push it with a few extra grunts and groans. That effort probably took less than 100 pounds of draw bar pull even though the car weighed several thousand pounds!
Imagine, now, that the air was let out of the tires and that the car had not been greased in five years and also that it was on a rough and rutted farm road. How far would you like to try pushing the car?
These same principles come into play in moving gates horizontally. A heavy gate may be easy or difficult to move depending on how good the rollers and track surfaces are. If it has reasonably good hardware and the track is level, then it won't take much force to move it along it's track. Conversely, a light-weight gate may take three men and a boy to move if the hardware is rusty, the bearings full of mud and the entire assembly is coated with ice!
Get used to the idea of drawbar pull. It is something you can measure with a fish scale and if you sell an operator to someone for a specific job and then the specifications change, you have a shelter to stand behind. The new gate that moves smoothly today may be a bear a month from now. Wouldn't it be nice to put the scale on the gate and be able to tell the customer that the gate needs to be serviced and the operator is not really the problem when the gate does not move?
Remember that the weight of the gate will not change, but the amount of pull to get it moving can change in a minute with the failure of one bearing! Protect yourself; deal in terms that you can defend. Drawbar pull.
HySecurity Gate Operators can push your gate all day long without regard to the number of cycles. There is a limit on how much drawbar pull we can exert on a slide gate. That limit is presently 300 pounds on a standard 222 SS operator. That is the equivalent of four or five guys pushing on the car that's out of gas! If the gate takes more pull than that, we have to go to a more powerful version of our standard operator.
Also it is well to remember that it takes a lot more to stop a load than it does to start it rolling. Go back to the "car out of gas" example. You could push your car out of the road by starting slowly and gaining some momentum. If you pushed it over the crown of the hill, how difficult do you think it would be to stop? Probably pretty difficult if it got rolling fast! All HySecurity slide gate operators have a "soft stop" feature, but a soft stop on a gate that weighs over 1000 pounds is a real tough job. You will note that we recommend the "E" version on the heavier gates, this is because we are trying to stop a "moving car". Again, we can start that heavy load easily, but it takes special valving and controls to bring it to a smooth stop every time.
A few more good reasons to specify HySecurity Gate Operators!
All moving gates are potentially dangerous. Pedestrian and vehicle traffic must never be combined. It is important to note that the risk of injury may be reduced by the use of sensing devices. HySecurity strongly suggests that the designer contact the factory for suggestions on how to make an automated gate less likely to cause injury or property damage.
When powering large electric motors, the higher the voltage the better; thus our first choice recommendation is always three phase power. If three phase is not available, 230 Volt single phase should be used. Single phase 120 Volt circuits should be avoided, even with 3/4 horsepower machines.
HySecurity Gate Operators will not offer any operator that employs a two horsepower, or larger, electric motor for connection to 120 Volt single phase electrical circuits. Additionally, we recommend that distributors avoid connection of any operator to 120 Volt circuits whenever possible. The reason for the restriction, and for our recommendation to avoid 120 Volt connections, is that the "starting current" of electric motors is approximately five times the nameplate "run current". This creates a high probability of destructive voltage loss in the branch circuit supplying the gate operator. Because gate operators, by their very nature, are frequently located a long distance from the main circuit breaker panel, we have known of many jobs where voltage drop due to a combination of long runs and undersized wire has caused substantial problems. Typical problems are: component damage due to chattering contactor and control relays, caused by the one horsepower motor pulling down the voltage as it draws sixty amperes to start; damage to the start switch inside the motor caused by hard, low voltage starts; possible resetting of the vehicle detector as the voltage dips during motor start; and tripping of the overload relay due to pitted and sticking motor start switches.
HySecurity Gate Operators feels that this voltage restriction/recommendation should not cause any hardship, since the source for all 120 Volt circuits is a 208 or 240 Volt panel. The only difference for the end user and installer is that a two pole circuit breaker must be used to provide the higher voltage. The installers should save money following this recommendation, because of the reduction in the wire size requirement. (See our wire size chart, E 16a,b.) As you know, HySecurity charges the same price for its operators regardless of voltage.
Even though HySecurity Gate Operators does not manufacture the gates that our operators move, we have gained some valuable insight into some major problem areas involving the gate panel and the manner in which it is applied. We are sharing that information with you; after all, if the gate hardware breaks down, it makes the operator look bad!
Since the most widely used gate type is the slider, or side rolling, we will deal with that type first. One of the areas least appreciated is that moving a slide gate can be compared to moving a car or even a truck, in some cases. A sliding gate constructed out of iron or steel tubes can weigh a lot more than a truck in some of the gates we have seen. In one instance, we were asked to move a gate weighing 58,000 pounds! And if that were not enough, we were told that it went uphill 3 feet over a travel of 85 feet! I think the point is made that gates must be treated as heavy machinery. You simply must provide adequate hardware. High quality bearings and wheels are a minor part of the total cost of a large gate installation. One of the best wheel bearings you can buy will probably cost no more than $40.00 per wheel for a 5,000 pound load. In other words, you can put high quality bearings in the two wheels of a ten thousand pound gate for around $80.00!! A pretty low cost insurance premium, I'd say.
Now that we have good wheels under the gate, all we have to do is provide something on which the wheels can travel. There are many good track designs available, including above and below grade applications. This is a good place to decide if a gate track really needs to be recessed. Recessed, or flush, tracks look nice, except when the gate won't move because the recess is full of debris! Recessed tracks, by their design, are trash collectors, so unless you have someone standing by to keep the track clear, don't do it. If the track must be recessed, then provide for easy clean-outs and the type of recess that will clean out easily with air or water. Jet fighter planes (as one example) cannot run over a track above grade. Their tires are so tender, and the air pressure is so high, that the surface over which they travel must be at grade. If a track is to be recessed, you should also try to provide a track that will not allow debris to rest on the surface of the track. One of the worst we have seen is a channel shaped recessed track and a flat wheel running in the bottom of the recess. Every pebble and grain of sand became, literally, grist for the mill. Since the wheel was as wide as the track, there was no escape from the debris, and the slightest bit of trash stopped the gate in it's "tracks". You must also remember that the slightest recess across the road will cause the vehicle tires to flex and lose the tiny pebbles that are wedged in the tread, so even an urban environment will not save you from the ravages of the recessed track. Semi-rigid rubber "sweeps" can be attached to the leading and trailing edges of the gate to help keep the large pieces of trash from collecting, but the best answer is to surface mount the track when possible.
By this time I hope that you are convinced that a recess track is not the way to go. When possible, a track above grade is the simplest and the easiest to care for of all types, and deserves your serious consideration. A track above grade is usually a simple inverted angle iron that is attached to a concrete grade beam or to a piece of structural steel and then embedded in a concrete beam. The exact method is determined by the type of traffic anticipated and the nature of the soils. For very heavy gates that are going to get a lot of traffic, a steel bar, two inches square, sliced on the diagonal, is better than angle iron. Over time, a steel track will wear, and that may dictate a solid track rather than hollow.
Regardless of the type of wheel selected, (there are many types from plastic to cast iron), specify a good quality, industrial grade bearing. The bearing should be sealed if it will be concealed in the gate panel construction. If it will be exposed then an exposed grease fitting is helpful. The theory behind greasing the wheels at a planned interval, is that the new grease displaces the old, and in the process, pushes out the grit and dirt in the old grease. Bearings of any kind running at the surface of the roadway are bound to collect their share of grit and dirt. On a light weight gate panel, (less than 800 pounds) a plastic, self-bearing wheel may be appropriate. The advantage of plastic bearings is that they don't need lubrication, and they will not wear out the track! On the other hand, plastic is soft and will take a "set" after a certain interval. This "set" is a flat spot that will not smooth out until it runs for a number of cycles. The exact measure of these phenomena depends on temperature, weight, time and of course, the exact type of plastic, and its hardness factor. Consult your wheel manufacturer before specifying. Bronze bushings are a step up from plastic and are generally used in metal wheels. They can be pressed into plastic wheels also, and this will eliminate half of the "set". The toughest bearing/wheel combination will be steel or iron wheels and roller or needle bearings. These are available with very high capacity ratings and any gate panel over 800 pounds should be considered a candidate for these very tough bearings and wheels.
Before leaving the discussion of the wheels and tracks, we must point out that one of the most abused products is the good old traditional cantilever hardware set that is provided by the fence contractor. Many designers or owners will specify the gate panel has to be no more than 2 inches off the ground. Well, that places the bottom wheels below the grade! You can imagine how long this hardware will last. Heavy-duty cantilever hardware has a wheel eight inches in diameter, and you can quickly figure out how far the gate panel will have to be above grade for this hardware to work as designed. There is now some very good cantilever wheel hardware on the market. Specify it! It will last for a long time and you will not have to deal with that problem.
Some manufacturers are producing good cantilever hardware that is top hung. It is possible to get the wheels up out of the mud!
One more thing about wheels. If you are designing a steel gate that will become a rigid diaphragm and will not flex, then you must calculate the load to be on only two wheels regardless of the number you put under the gate. Think about this for a minute. If you have an imperfect gate panel or track on the ground, (and you will have) there will be times that only two of the wheels will be doing all of the work. We have seen cases where such a gate was placed on five wheels, with the idea that each would share one fifth of the load. Wrong! Because of the imperfections mentioned above, and because there was a wheel placed at the center of the gate, one of the wheels took the entire load at the moment the gate passed over a slight hump in the track! This became a 15,000 pound load on one wheel that was designed for a 3,000 pound load! The cast iron wheels used on this job shattered like glass. The solution is to design for two wheels or if more wheels are desired, allow the gate to flex. Do not construct the gate to be rigid.
Problems with swing gates usually have to do with the size and weight more than anything else. One thing to remember about swing gates is that a lot of gate operators will travel at a given speed, regardless of the gate size. This means that a 6-foot wide gate will close just as fast as a 16-foot wide gate. Imagine how this translates to the gate tip speed. The 6-foot gate tip travels nine feet to close. The 16-foot gate travels twenty five feet. The tip speed is over two and one half times as fast on the longer gate, even though the operator is going the same speed for both! When you consider that the gate has to stop when it gets to the end of its travel, you could be creating problems for your client by specifying very large gates. So many manufacturers now make operators with different speeds for different weight gates.
Similar problems can be created with barrier arm and vertical lift gates. Make certain that the gate weight and speed are considered in the design phase.
One last comment on problems that face the gate operator manufacturer: The lack of attention to the power requirements of the equipment. Long power runs or wire that is too small will cause all kinds of problems and finger pointing if not covered directly in the specifications. Operator manufacturers will furnish recommendations.
HySecurity Gate Operators does not manufacture gate panels, or the wheels that support gates as they travel. We are often asked for our input on gate and gate hardware by architects designing various projects.
Over the years we have seen a lot of ideas that do not work and few that work very well and seem to get used over and over again. The design ideas that follow are not original by any means. They do represent ideas that work and they may help you in selecting an idea that will work on your project.
A network of distributors and dealers represents HySecurity Gate Operators across the entire country and designs must vary according to local weather and environmental considerations. We are happy to put you in touch with a knowledgeable distributor in your area for additional help with designs or budgeting. Call us on the toll free line for help in this area.
SPECIAL NOTE: There is an increasing emphasis being placed on safety, as more and more security gates are being used. HySecurity urges you to avoid the use of "open picket" type gates. Open picket gates, if used, should be covered with small mesh to protect against "reach through" and "ride along" hazards. The opportunity for someone to put an arm or leg through this type of gate may lead to serious injury. Other potential pinch points can occur if exposed cantilever hardware is used. Any exposed rollers must be covered to protect feet, fingers and hands. Do not overlook the space into which the gate slides as it opens. This is a potential hazard area. Please take the necessary precautions to protect those who will be using the security gate and those who just happen to arrive when the gate is being used. A separate access gate must be provided for use by pedestrians. Cars and humans do not mix well at all. Please ask us for help if you have any questions about providing safety on your security gate application. We can offer help in this area.
One more thought, use good quality hardware. There is very good and very poor quality hardware available on the market. The difference in price is very small between the very good and worst. Good quality hardware will add a lot of life to the reliability of the entire job.
Don't be shy; call us if we can assist you and your client in this very important part of your project.
Limited Warranty Hydraulically Powered Operators
HySecurity Gate Operators warrants all of its manufactured products to the end-user to be free of defects in material and workmanship. The model 111LS is warranted for a period of three years from date of shipment. (The ESP 814, pneumatic operator carries a separate warranty, see form W-15.) All other operators are warranted for a period of five years from date of shipment. Slide gate operator drive wheels are warranted for a period of two years from the date of shipment.
Any modification made to factory products will void the warranty unless the modifications are approved in writing by the factory, in advance of the change. This exclusion does not apply to normal installation of approved accessories and/or safety devices. Even though included as part of a HySecurity gate operator, accessories carrying another manufacturers name plate, (unless a design component of the gate operator, excluding DC power supplies and batteries) shall carry only the warranty of the specific manufacturer. This warranty shall not apply to equipment which has been improperly installed, subjected to negligence, accident, damage by circumstances beyond HySecurity Gate Operators' control, or because of improper operation, maintenance, storage or to other than normal use or service.
Labor to install new parts or remove defective parts, travel time, or standby time is specifically excluded from this warranty. Freight (surface or air) and all other incidental costs are NOT covered by this warranty. There are no obligations or liabilities on the part of HySecurity Gate Operators for consequential damages arising out of, or in connection with, the use or performance of this product. HySecurity Gate Operators assumes no responsibility for other indirect damages with respect to loss of property, profit or revenue. This Limited Warranty is valid only in the 50 United States, the District of Columbia and the Commonwealth of Puerto Rico. Implied warranties, including those of merchantability and fitness for a particular purpose or application, are limited to one year from date of shipment.
Defective products that are in warranty should be returned to our factory. At our option, we may elect to repair or replace, free of charge, any such parts. A memo invoice will be sent at the time replacement parts are shipped, and a credit will be issued to cover the material cost when the defective parts are received. No warranty credits will be allowed without written permission from the factory, and the return of the defective part, together with a completed RMA form. Replacement parts shall carry the remainder of the original limited warranty or 90 days, whichever is longer.
This Limited Warranty gives you specific rights. You may have others, which vary from state to state. This HySecurity Gate Operatorsí limited warranty is in lieu of all other warranties expressed or implied. This Limited Warranty supersedes all other warranties.