IDEA #4BUHSN Mechanical anti-rotational feature for subsea wellhead housing

An anti-rotation device prevents an inner wellhead housing from rotating within an outer wellhead housing. The anti-rotation device provides spring loaded anti-rotational keys within the outer wellhead housing and mating slots formed within the inner wellhead housing. The keys face inwards to the inner wellhead housing, are circumferentially spaced apart around the outer wellhead housing, and located between the two tapered shoulders. As the inner wellhead housing lands in the outer housing, the inner wellhead housing pushes the keys of the outer wellhead housing to a retracted position. The inner wellhead housing is then rotated within the outer wellhead housing until the spring loaded keys align with the slots and extend into the slots of the inner wellhead housing. Any rotational force on the inner wellhead housing will be resisted by the anti-rotational mechanism. https://app.acclaimip.com/pdf/KHeL769VYe1rd4uKSlVh4QAuCtV5MCRfL0RvNCk/US6695059B2