The Love Knot, as I use it at least, falls into the category of quaternary knots. Quaternary knots are knots with four “poles” or axes to their pattern.
As simple as the pattern is, it isn’t surprising that it is a very old pattern. It also shouldn’t be surprising that, like most other basic symbols, it has held many different meanings for many different people. The four winds, the four elements, the four celtic fire festivals. One school of thought holds that they represent the four Canonical gospels, as first described by Irenaeus of Lyons, in roughly the year 185. This is regarded as a recent development, which gives us a good historical perspective for the age of symbols like this.
As with most things in life, the meanings they hold are the ones we give them ourselves. I think love is something we all need a little more of, in every aspect of our lives, and that is the meaning I associate with the knot. You may choose instead to see them as Ringo, George, Paul, and John, but they would probably side with the love definition.