A solenoid built into the latch receives an electrical impulse of about 26 volts when someone enters the correct code on the keypad outside the gate. With a loud buzz, a plate is pulled back within the latch by the solenoid, allowing the latch to swing freely out of the way when the gate is pushed. After ten seconds the voltage is cut and the plate snaps back to prevent the latch from allowing the gate to open.
After a recent flurry of guests (about 50 in one afternoon) the latch stopped stopping! The gate would just bounce against the stone when it slammed, and the gate could just be pushed open at will, even by the wind, and then Gideon
Having repaired this same latch almost 5 years ago, I wasn't all that excited to take it apart to figure out what was going on, but I could tell things were askew in there and that 'surgery' was indicated. Here's how it looked then, in December of 2006:
After I chipped away the mortar holding the housing in place, got it on the bench and opened it up, I removed the latch/solenoid mechanism and put it in the vise.
The solenoid is in the upper section, the latch in the lower. |
The latch itself was breaking around the pin! in two places! And the pin was bent from the repeated stress of the gate banging against it. So now, instead of just putting it back together, I had to have a new latch. I didn't want to put this one back in service just to have it break again in the near future.
Fortunately, I had a new latch/solenoid assembly with which to replace the whole unit. Unfortunatley, the new unit was in a housing of an entirely different shape and size.
Fortunately I could fabricate a hardwood block into which I could mount the new latch assembly that would allow for future servicing by being removable and yet sturdy enough to hold up to rough duty at the gate.
I hooked up the wires and pressed the code into the keypad. "Buzz", said the latch, and I physically operated the latch with my finger to prove it was released by the solenoid. I then proceeded to mount the assembly.
But when I finished and stood back to test it again, unfortunatley it didn't work, no buzz, no nothin'. Partial disassembly and tried the code again..."buzz", okay, we're in business! Reassembly, but then, no buzz, no work!
After removing the assembly once more, I measured the voltage at the gate wire to be 25.9 volts. Checking the rating label on the new solenoid latch I saw this:
Okay, so I must've burned up my new solenoid with too much voltage. I wonder if I can mount the old solenoid in the new housing?
Fortunately, the old one was still functional and I was able to fit it into the new housing by cutting away some of the steel plate on which the old solenoid was mounted.
The new, burnt-out solenoid is on the right, the old, modified one is on the left; the blue tape is the pattern I used to make the cuts. |