Wouldn't that be Stanley Sweet Heart? The logo was a heart with S.W. inside of it. That particular logo was used from 1920 to 1934. Its a pretty good way to date your tools to a very small window of time.
Stanley has started to use that logo again recently for their "premier planes".
I was quite interested in one of their new Sweetheart block planes right upto the point when I picked on up. The adjustable mouth doesn't close up anything like as close to the blade as I would like, there's too much backlash in the Norris style adjuster (no fault of the style of adjuster, its just that the hole in the blade that the adjuster fits into is too big) and the part that the blade beds onto wasn't ground properly and the blade needed to be adjusted on its lateral adjustment to sit straight.
The final point isn't so much of a problem as its easy to do but the backlash and especially the mouth not closing up as close to the blade as it should are pretty unforgivable.
Its like the bloke who designed it and checked it of the production line had never used one.
I wouldn't mind but as most of these faults just take a little more thought at the design stage I can't see it adding too much the the manufacturing cost.
I wanted to like the one I picked up but couldn't because it was too sloppy.
Plus, I'm not entirely sure where its made...