Oh...well, then, nevermind the gato's
addendum: scribble
http://img83.imageshack.us/img83/9780/gatefk0.png
Your hinge mechanism is actualy just one pipe, slid over a slightly smaller one. The smaller on is anchored in the ground, and has a "washer" welded to it that your gate hinge tube rests/rotates on, grease this.
At the top, for strength, you tie the top of the smaller tube into the fence posts. For the pup, add chainlink to the gate, or get an "invisible fence".