Keilim 18:3-4

Keilim 18:3

If one of the legs is missing from a chest, a counter or a cupboard, it is insusceptible to ritual impurity even though it can still hold things because it can’t hold them in the usual manner; Rabbi Yosi, however, says that the object remains susceptible to impurity. The poles, base and cover of a bed are insusceptible to ritual impurity; only the bed and its frame are susceptible. The frames of Leviim are insusceptible. (Since they were routinely removed and transported to and from Jerusalem, the frames of Levites’ beds were not considered permanent attachments.)

Keilim 18:4

If a bed frame is placed on props, Rabbi Meir and Rabbi Yehuda say that it’s susceptible to impurity while Rabbi Yosi and Rabbi Shimon say that it’s insusceptible. Rabbi Yosi explains his position by saying that this is no different from the bed frames of Leviim, which are insusceptible.