shalom uberacha
besof hadaf neemar ´´ machshich alehem umeviam´´
vehisbir rav itschak beshem aviv shemedubar shelo yatsliach lehachnis et
kulam kodem shekiat hachama.
rashi omer she enam kalot kodem shekiat hachama veyistarech lachzor mishetechshach.
ma yihiye lemashal im hu matsa 10 zugot 8 dakot lifnei shekiat hachama ;
hu yachniss 8 lifnei shekiat hachama ve shtaim b ben hashnashot (shenimshach beerech 13,5 dakot) vekacha lo yistarech lachzor mishetechshach.
lama neemar kodem shekiat hachama velo neemar kodem shetachshich o kodem tset hashabat???
toda raba mirosh
albert battat
sao paulo brazil.
(Translation: Rav Yitzchak explains that when there are many pairs of Tefilin which one will be able to bring in before Shekiah by wearing one pair at a time, then he must toil to bring them all in. If there are so many that he does not have enough time to be able to bring them all in before Shekiah by wearing one pair at a time, then he leaves them there and brings them in immediately after Shabbos.
What will be in a case, for example, when he finds 10 pairs of Tefilin about eight minutes before Shekiah (sunset), and he is able to bring in 8 pairs before sunset and 2 pairs after sunset during Bein ha'Shemashos (which lasts for about 13.5 minutes). Why does the Gemara say that only if he can bring all of the Tefilin in before sunset , and not before nightfall or the exit of Shabbos?)
"Shekiah" does not necessarily mean the beginning of Shekiah. It can also refer to the end of Shekiah, which is the same time as the end of Bein ha'Shemashos and nightfall.
(Furthermore, although the Halachah follows the opinion that Bein ha'Shemashos is an extended period of time, the duration of Bein ha'Shemashos is subject to a Machlokes Tana'im, as we saw in Berachos (2b). Rebbi Yosi maintains that Bein ha'Shemashos is a fraction of a second.)
However, it seems that even if Shekiah refers to the beginning of Bein ha'Shemashos (as TOSFOS indeed says in Zevachim 56a, DH Minayin), the time limit by which one must be able to bring in all of the Tefilin is by Shekiah, because Bein ha'Shemashos has a status of Chol, and not Shabbos, with regard to these Halachos (since the reason the Rabanan allowed a person to wait until Shabbos to bring in the Tefilin was so that he would not disturb his Oneg Shabbos by spending the entire time carrying in Tefilin).
(Translation: Nir'eh she'ha'ikar terutz l'she'eilatcha hu she'Bein ha'Shemashot yesh lo din shel Chol l'inyan ha'halachot ha'eilu. Ha'Rabanan hekeilu aleinu v'lo hitzrachnu l'tro'ach b'chol ha'shabbos kulo k'dei l'hikanes et ha'tefilin, im nivaleh et kol ha'shabbat v'lo yiheyeh lanu oneg Shabbat. Lachen hechshivu Bein ha'Shemashot lihiyot k'chol, v'zeh kula kiday she'yakel aleinu. B'mashal shelcha, im rak yiheyeh yachol lihikanes et shenei ha'tefilin ha'nish'arim achari bein ha'shemashot, b'matzav ka'zeh Chazal lo chayavu otanu li'tro'ach b'shabbat, keivan she'gam l'achar shabbat (hayinu, bein ha'shemashot) yitztarech li'tro'ach.)