May one use the stick attachment of a vacuum cleaner as a way to lock a door on Shabbos? Is it considered muktza even if one is using it for a permitted purpose?
The stick attachment of a vacuum cleaner essentially is not used for anything else but vacuuming the floor. Therefore since it doesn’t have any other reasonable use, (most people that I know don’t do things like this with a vacuum cleaner stick) it is considered a li shmilachto l’issur that doesn’t have a heter use, similar to moving a candle if it’s place is needed. There is much controversy among the poskim (see sources) if it is allowed to be moved or not. R’ Eliyashiv ruled that it should not be moved unless it is very necessary.
Ran, Ritba Shabbos 44b, R’ Akiva Eiger Mishnayos Shabbos Perek KIra, Pri Megadim E:A 308- 12, Aruch Hashulchan 279-1, M:B 279-4, Tiltulei Shabbos in the name of R’ Moshe Feinstein, Shevet Halevi 10-59, Chazon Ish O:CH 44-13, Be’er Moshe Kutntris Electric 6, Orchos Shabbos 19 ftnt. 20. See Shalmei Yehuda Pesicha 6 ftnt. 22 who discusses this at length.