Over the years the subject of automatic sliding gates on slopes has reared its ugly head many times.
This is specifically about automatic gates that open and close on two wheels that run along a track fixed to the ground.
Over 15 years ago, when I started in the business, gate automation manufacturers would tell me that an incline of up to 4% was acceptable for sliding gates. That gives a height change of 4 cm for every meter of track. With a typical 6m track length, that means a total height change of 24cm!
Of course, this was in the days before the tragedies that have illustrated an automatic sliding gate’s effectiveness as a horizontal guillotine. Thankfully, we have obstacle detection that can prevent such tragic loss of life and horrific injury but how does this affect the working requirements of sliding gate motors?
Slider motors are designed to move an automated gate backwards and forwards by getting it moving and stopping it on level ground. They are not built to cope properly with the completely different forces at work when either driving automatic gates up hill or controlling them as they descend. Even without clever electronics, this type of use is likely to lead to rapid problems with mistreated gearboxes if nothing else.
These days, most slider motors are equipped with obstacle detection that is built into the electronics. These motors are definitely confused by the different forces involved when operating a slider on a slope, so there are likely to difficulties in even setting them up in the first place.
For the last few years I have not found a gate automation manufacturer who will recommend their equipment for use with gates on a slope of any kind. Even with safety edges it would probably be impossible to guarantee that such an installation meets today’s requirements for gate automation safety.
If you have a slope, and need the benefits of a slider, the best answer is to either level the ground or use a cantilever gate.
Automate My Gate 
From many years ago A level physics tells me that a 4 deg slope would lead to a 6.9% horizontal component e.g a 100KG gate would add/subtract 6.9KG appx 70N of force. 3 deg 5.2%, 2 deg 3.5%, 1 deg 1.7%
This calculation is very useful, and in the old days before force meters we were taught that the leading edge of a gate should not have a force of more than 15Kg 150N, this calculation shows how difficult it is to set up a gate weighing more than 200Kg or so on a 4% slope even without the complication of obstacle detection
no sliding gate should be installed on any sort of slop! reagrdless of the safety devicies what happens when the gate is put to manual opertaion during a power cut????? alan j smith at gate-a-mation ltd.
I wasn’t advocating deliberately mounting on a slope, just the physics.
Also the numbers given represent the force component generated by gravity; momentum, friction, speed, inertia all contribute to actual impact forces.
I am glad to see professionals in the industry agreeing on safety issues, but check out my next post in a couple of days where I will be expanding the discussion.
We multiply the gate weight x 4 when any slope is present and we install back up batteyr on all motors so manual release is not an issue. Havent had any trouble to date
power supply issues are not the only time gates manual release are used!
This is very interesting, as I previously thought tracked sliding gates had to run on flat surfaces only!
This makes it much easier to decide on how to choose a tracked sliding gate for my home.
This is very useful article for me for design and uses of cantilever gate
Thank you.