Excavators in general have two types of quick couplers. Pin grabbers and wedge locks. Pin grab couplers will grab onto buckets with standard lugs and the pins left in all the time. The most common types have a hydraulic cylinder powered from the machine that will force one or both jaws apart to grab the pins and hold the bucket. There are manual versions of these using lead screws or big bolts and others with a cam over mechanism. I'll have to search through some of my files to find some of these.
The wedge locks styles use buckets that have a special set of mounting lugs installed on them. The front of the coupler locks into the front part of the bucket lugs and the back part of the coupler just sets against the back of the bucket. A wedge is driven in between the lugs on the bucket and a mating part on the coupler and two bolts are installed to keep the bucket and coupler mated together.
The wedge style couplers maintain the distance from the stick pin to the bucket teeth so you don't loose and digging force. However the lugs and wedges wear out over time and get loose. This style also locks you into only one type of bucket mounting. The pin grabbers increase the distance from the stick pin to bucket teeth or lip so provide a little bit less digging force. Most operators though can't tell the difference. The pin grabbers give you a lot more options and abilities to use different buckets. The pin grab couplers themselves are a little more expensive to purchase but then you don't have to buy buckets to go with them. When I get time to go through the photo archives I'll post some photos of each type.
The other style of bucket you mentioned was a Wain Roy style. I've never seen them used for excavators but that doesn't mean it couldn't be done. I've seen plenty of them on loader backhoes. Basically there is a hook on the coupler that fits through a hole in the top of the backhoe bucket. When the hook is rotated through the hole a mating boss lines up with a lug on the bucket and a pin is inserted. All I've ever seen of these were manual latches. They are cheap, don't take well to abuse and don't last long even if not abused. I've seen these mostly in rental fleets.
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