Why a slide gate sags or binds partway
The scrape that starts a few feet into the travel and the groan from the operator behind it almost always trace back to the track or the posts, according to the figures kept at sliding gates georgetown apollo pony for gate work around Georgetown, TX. The motor gets blamed first, but a gate opener only pushes what the frame lets it push.
Where does binding start?
Binding at one spot in the travel means something on the run is out of line at that spot, such as a high place in the track, a bent section of rail or a post that has leaned into the path. Binding along the whole travel points at the wheels or a leaf that has racked out of square. A crew rolls the gate by hand with the operator released and marks every place it tightens.
Why does the tail sag?
The tail of a cantilever gate sags when the carriage posts lean or the frame cracks at the first carriage. The leaf is a long beam held at two points, and any lean in a post tips the whole line downward at the far end. In Williamson County clay a shallow post can lean after one wet spring, and the tail then drags on the ground.
What do cracked welds look like?
A cracked weld shows as a hairline of rust at a joint, usually where a vertical meets the bottom rail or where a brace meets a corner. A weld that flexes under travel opens a little more each cycle. The frame racks into a parallelogram and the bottom rail drops at one end. Repair means grinding out the crack, welding new bead and adding a diagonal brace so the frame stays square.
How does a gate jump the track?
A gate jumps a track when a wheel climbs a stone, a clump of mud or a raised joint in the concrete. It happens more after a storm washes grit into the groove. A track with a shallow channel jumps more easily than a deep one, and a worn wheel with a flat rim climbs out of the groove sooner. Clearing the track and replacing flat wheels usually ends it.
When is the motor really at fault?
The motor is at fault when the gate rolls freely by hand yet stalls on power. A limit set too short, a clutch set too tight or a failing capacitor each stop a gate that is mechanically sound. The simple test is to release the operator, push the leaf end to end and note how it feels. A leaf that moves with two fingers has a fault in the drive, and one that fights back has a fault in the steel.