Mishnayos Keilim Perek 23 Mishnah 4

המטה והכר והכסת (the bed and the mattress and the cushion) – even though that the corpse does not defile through treading, and these are made for a corpse but not to sit upon, even so, they defile through treading, because the women sit upon them [and bewail their dead] (see Tosefta Kelim Bava Batra, Chapter 2, Halakha 8).

ומשבר של חיה (the travailing chair of the midwife) – the sitting place of the woman who is giving birth. We translate into Aramaic that of (Exodus 1:16): “[When you deliver the Hebrew women, look] at the birthstool: on the travailing chair/על מתברא.

שהוא כורם עליו (upon which he piles the clothes – to press them) – we have this reading. Meaning to say, that he folds and repairs there the clothing.

אמר ר' יוסי אין בהן משום מושב – and our Mishnah of the chapter that is above (Tractate Kelim, Chapter 22, Mishnah 7) where it is taught: "כסא של כלה שנטלו חפויו"/”Also a chair of the bride whose seat boards have been removed” which implies that if the seat boards had not been removed it is ritually impure. This is in conflict with Rabbi Yossi. But the Halakha is not in accordance with Rabbi Yossi.