Patent ID: 6050032
Filing Date: 2000-04-18
Classification: E04G,E05F,E06B

Abstract:
An apparatus comprising:a slab having a plurality of support holes;a rectangular hatch formed in said slab, said hatch having a first pair of opposing sides and a second pair of opposing sides; anda fence surrounding said hatch, said fence including:a plurality of gear mechanisms at each of said first pair of opposing sides of said hatch, each of said gear mechanisms including: a first gear, a second gear in mesh with said first gear, a first shaft arranged parallel to said first pair of opposing sides and supporting said first gear, a second shaft arranged parallel to said first pair of opposing sides and supporting said second gear, and a counterweight mounted to said second shaft;a plurality of brackets secured to each of said first pair of opposing sides of said hatch, each of said brackets having a pair of bracket portions supporting said first shaft of one of said gear mechanisms and said second shaft of said one of said gear mechanisms therebetween;a pair of lids having lower ends connected to said first gear of said gear mechanisms, respectively, such that each of said lids is capable of pivoting between an erect position and a lowered position, each of said lids covering about half of an opening formed by said hatch when said each of said lids is in said lowered position;a plurality of extensions retained in said support holes of said slab; anda plurality of side frames arranged along said second pair of opposing sides of said hatch and having support poles, each of said support poles having an end connected to one of said extensions by a pivot pin such that each of said support poles is capable of pivoting about said pivot pin, whereby each of said side frames is capable of pivoting between a first lowered position whereat said each of said side frames extends over said hatch, an erect position whereat said support poles are retained in said support holes, and a second lowered position whereat said each of said side frames extends over said slab;wherein at least one of said support poles comprises a swivel support pole including an upper pole portion having a shaft extending from a lower end thereof and a lower pole portion having a sheath receiving said shaft, said shaft being capable of rotating within said sheath, and wherein at least one of said support poles comprises a latch support pole including an upper pole portion and a lower pole portion, said upper pole portion of said latch support pole being separably connected to said lower pole portion of said latch support pole by a connection pin, and wherein at least one of sad plurality of side frames includes one of said at least one of said support poles comprising a swivel support pole at a first end and includes one of said at least one of said support poles comprising a latch support pole at a second end opposite said first end, and wherein said at least one of said plurality of side frames is capable of pivoting about said swivel support pole between an open position and a closed position by disengaging said connection pin;wherein said fence is formed by arranging said pair of lids in said erect position and by arranging said plurality of side frames in said erect position.