Talk:Garage door opener

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This article only discusses the transmitter & reciever. It needs to cover the actual door opening mechanism and safety interlocks as well.--Hooperbloob 07:34, 31 July 2005 (UTC)

[edit] safety devices

Door opener systems are required to have at least two safety devices that will assist in preventing the door from shutting on an obstruction (a car, a box, a pet, a person, etc.). Originally door opener manufacturers incorporated pressure sensing circuitry that compared the normal operating forces working against the opener to any changes in the force required to open or close the door and would stop or reverse the door when the force required to move the door exceeded the threshold level. The amount of pressure (force) to open and close the door, and the associated adjustments thereof are commonly referred to the "open force" and close force". There are threshold limits for these forces that are commonly in the neighborhood of 10 pounds of pressure. Thus, it is very important to properly maintain a door so that the door opener does not have to exert an overt amount of force to either open or close a door. As technology advanced there arose a need and the capability to incorporate an additional safety device commonly referred to as safety sensors. Typically the sensors operate by sending an infrared beam across the opening, within five inches of the ground, from one sensor, "the sending eye" to a sensor located on the opposite side of the doorway know as the "receiving eye". When the door is in motion and something breaks the invisible beam across the doorway, the door will reverse to the open position if travelling down and will stop if the door is travelling up. This type of system has been required since 1992 in all residential door opener systems to prevent doors from striking objects in the downward motion and hooking onto objects in the upward motion. An additional feature of this safety sensor system is to turn the lights on on the door opener if something breaks the invisible beam.