Sven, Classicsat has it right, P&S "Surfex" The screw you speak of was missing when I found this guy... I used to have some old Leviton surface mount recepts & switched from the same era... I think my garage swallowed them
The pushbutton switches are still in pretty good shape as well, for being over 100 years old! The single 4 slot recepts I think were original from when the house was built, they were by far, the most worn out things in that place.. (cords taped to the wall to keep them in the recepts! ) The duplex 4 slot is one I haven't ever come across before.. Mfg by "Hoosick"?
Sven, I see the laziness thing constantly! (See "Ceiling fan running on Tstat wire" in the photo/discussion forum) Every outlet in that house seemed to have a power strip stuck in it... The P&S surface mount recept was actually wired with something resembling early romex, running under a window behind some mitered out wood molding.. Full entertainment center running there... The other 2 surface mounts were zip-cord fed off other recepts.. I remember, the power strips plugged into the single recepts with a "cheater" were mostly running small things (thankfully) table lamps, clock, radio, etc... & maybe an occaisional vacuum... Her bathroom didn't have an outlet... There was a keyless on the ceiling with a built in recept.. She had an extension cord, (looked like it'd been there since the 50's) coming from the ceiling (18 awg) for a hair dryer...
I have only seen one of those 4-pronger receptacles once, but actually it was part of an ANCIENT electric parabolic heater. the cord was standard HPN heater cord with a regular cap on it but the female end was one of those 4-pronger ends, and fit right on the back of this heater using the tandem slots. you could also plug in a standard parralell blade plug into that same cord end.. Bizarre I thought. A.D
Dawg, Those are the precursor to the "T-Slots" that you've been inquiring about... If you look at it, realize that only 2 of the 4 slots were utilized at one time. a NEMA 1-15 plug would fit vertically, and a 2-15 horizontally.. If I remember right, their's continuity between the top & right slot, then the bottom and left. It would be trippy if they had designed these to output 2 separate voltages from one outlet point, but these all just had 2 terminal screws. These came from an old house I rewired (circa. 1900) in Compton, CA.