Moving tefillin on Shabbat

Hi,

Tefillin fit into the category we have defined as Kli sheMelachto l'Issur, since their primary function is prohibited on Shabbat.

However, the status of tefillin is more lenient than that of other "kli shemelachto l'issur" cases, because the act of donning tefillin is not actually a prohibited melachah. It is only that donning tefillin, for the sake of the mitzvah, denies the special character of Shabbat.

Therefore, we are lenient and we permit people to move tefillin if they are left in a degrading position. Also, if tefillin are accidentally left in a tallit bag, such that one cannot access the tallit, one may remove the tefillin in order to reach the tallit.

(Shemirat Shabbat k'Hilchatah 20:14)

Have a great day,
Mordechai