Back Drive garage door opener system

[RENATO]

Hi, why can't garage door opener systems be back driven (be opened by simply pushing or pulling the door), is there a locking mechanism or maybe the motor has a holding torque, or just the worm gear that locks the door in place? I am referring to chain systems.

But if it is just the worm gear, why is it made of plastic if this is what is stopping the door form being opened from outside.

Hope to hear your responses.

Have a good one.

[gilbdoor]

A worm gear is made to drive a ring gear and a ring gear cannot drive a worm gear. Therefore, the motor driving the worm gear moves the door, the door cannot turn the worm gear backwards by turning the ring gear.

The ring gear is made of plastic for the 3rd safety system of the garage door opener. If the door were to come down on a vehicle and the photo eyes don't see it and the rpm sensor doesn't function properly then the worm gear is made to strip off before to much damage or death occurs.

[TJR]

If we are talking LiftMaster, Chamberlain and Craftsman opener with a worm gear and ring/drive gear. I have never seen a worm gear cracked or worn down with normal use. What to wear out first is the drive gear, many times as the grease dries up and there is no lubrication. I have seen damage to the drive gear and cracked drive gear as the trolley over time repeatedly hitting the stop bolt/tap either open or close and that will break the gear.
On some other brands I have seen the drive gear crack with less force and damage to the worm gear. One brand had a steel worm gear and it broke the shaft for the worm gear, it was a dc opener with a slow start and stop.
If you are concern about your safety and some can force the door open. Then might think about replacing the opener with a LiftMaster 8500.
It has a Power Lock Deadbolt ensures the door cannot be forced open. And the motor lock the torsion spring bar.