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NTIS 바로가기국가/구분 | United States(US) Patent 등록 |
---|---|
국제특허분류(IPC7판) |
|
출원번호 | US-0842903 (1977-10-17) |
발명자 / 주소 |
|
인용정보 | 피인용 횟수 : 31 인용 특허 : 0 |
An insulating cover larger than and fitting over the opening in an upper floor between the upper floor and an adjacent lower floor of a structure which has an open top, box-like shape with a pair of wheels on its back wall and front inside and outside handles. Optionally, the edges of the wall have
An insulating cover adapted to fit over an opening between the upper floor and the lower floor of a structure in which a folding stairway selectively provides access between the floors and wherein the bottom of said opening is closed by a trap door, when the folding stairway is in the folded positio
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