US6256946B1 — Adjustable stairway for use with an overcast in a…

Claim 1

Independent Claim 230 words

A stairway for a mine air crossing installed in a mine passageway, comprising: a pair of elongate generally parallel supports at opposite sides of the stairway, each support comprising upper and lower parallel stringers disposed one above the other at a respective side of the stairway; a plurality of generally horizontal steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports; two horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway whereby said steps remain generally horizontal regardless of the angle of inclination of the stairway and regardless of a mine convergence or divergence causing a longitudinal shift of an upper stringer relative to a lower stringer; and handrails mounted on the steps at opposite sides of the stairway; each handrail comprising a plurality of generally vertical posts each having a lower end attached to a respective step and an upper end, and a hand bar having generally horizontal pivot connections with the vertical posts adjacent their upper ends, said hand bars being removable from respective posts so that when the stairway is moved to a position in which said supports are vertical, said vertical posts of the handrails are positioned to be grasped by a person climbing the stairway.

Claim 2

Dependent Claim 230 words

A stairway for a mine air crossing installed in a mine passageway, comprising: a pair of elongate generally parallel supports at opposite sides of the stairway, each support comprising upper and lower parallel stringers disposed one above the other at a respective side of the stairway; a plurality of generally horizontal steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports; two horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway whereby said steps remain generally horizontal regardless of the angle of inclination of the stairway and regardless of a mine convergence or divergence causing a longitudinal shift of an upper stringer relative to a lower stringer; and handrails mounted on the steps at opposite sides of the stairway; each handrail comprising a plurality of generally vertical posts each having a lower end attached to a respective step and an upper end, and a hand bar having generally horizontal pivot connections with the vertical posts adjacent their upper ends, said hand bars being removable from respective posts so that when the stairway is moved to a position in which said supports are vertical, said vertical posts of the handrails are positioned to be grasped by a person climbing the stairway.

Claim 3

Dependent Claim 176 words

A stairway for a mine air crossing installed in a mine passageway, comprising: a pair of elongate generally parallel supports at opposite sides of the stairway, each support comprising upper and lower parallel stringers disposed one above the other at a respective side of the stairway, said supports having opposing inside faces defining an interior space therebetween; a plurality of generally horizontal steps extending between the inside faces of the supports, each step having a front edge, a rear edge, and opposite ends; two horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway; and said horizontal pivot connections include knock-down connections configured for easy assembly and disassembly of the stairway, said knock-down connections comprising a plurality of holes in said stringers and a plurality of pivot members removably attachable to respective steps and stringers, said knock-down connections being securable from a position outside said interior space to facilitate assembly and disassembly of the stairway in a mine.

Claim 4

Dependent Claim 176 words

A stairway for a mine air crossing installed in a mine passageway, comprising: a pair of elongate generally parallel supports at opposite sides of the stairway, each support comprising upper and lower parallel stringers disposed one above the other at a respective side of the stairway, said supports having opposing inside faces defining an interior space therebetween; a plurality of generally horizontal steps extending between the inside faces of the supports, each step having a front edge, a rear edge, and opposite ends; two horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway; and said horizontal pivot connections include knock-down connections configured for easy assembly and disassembly of the stairway, said knock-down connections comprising a plurality of holes in said stringers and a plurality of pivot members removably attachable to respective steps and stringers, said knock-down connections being securable from a position outside said interior space to facilitate assembly and disassembly of the stairway in a mine.

Claim 5

Dependent Claim 20 words

A stairway as set forth in claim 2 including handrails mounted on the steps at opposite sides of the stairway.

Claim 6

Dependent Claim 40 words

A stairway as set forth in claim 3 wherein said steps have bottom surfaces and said pivot members include elongate rods extending through the holes in the stringers and through channel members secured to the bottom surfaces of the steps.

Claim 7

Dependent Claim 43 words

A stairway as set forth in claim 3 wherein said steps having bottom surfaces and said pivot members including first threaded members extending through the holes in the stringers and threadably engaging second threaded members secured to the bottom surfaces of the steps.

Claim 8

Dependent Claim 24 words

A stairway as set forth in claim 5 wherein said first threaded members including bolts and said second threaded members including internally threaded members.

Claim 9

Dependent Claim 198 words

A stairway for a mine air crossing installed in a mine passageway, comprising: a pair of elongate generally parallel supports at opposite sides of the stairway, each support comprising upper and lower generally parallel stringers disposed one above the other at a respective side of the stairway; a plurality of generally horizontal steps extending between the supports, each step having a front edge, a rear edge, and opposite ends; two generally horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway, said upper and lower stringers of each parallelogram adapted to be freely longitudinally movable relative to one another after installation of the stairway to accommodate a change in the angle of inclination of the stairway, as during a mine convergence or divergence. without causing said steps to move out of their said generally horizontal position; a generally horizontal landing attached to the supports adjacent upper ends thereof; and means for fastening the landing to an upper surface of the air crossing thereby to secure the stairway to the air crossing and set the angle of inclination of the steps.

Claim 10

Dependent Claim 198 words

A stairway for a mine air crossing installed in a mine passageway, comprising: a pair of elongate generally parallel supports at opposite sides of the stairway, each support comprising upper and lower generally parallel stringers disposed one above the other at a respective side of the stairway; a plurality of generally horizontal steps extending between the supports, each step having a front edge, a rear edge, and opposite ends; two generally horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway, said upper and lower stringers of each parallelogram adapted to be freely longitudinally movable relative to one another after installation of the stairway to accommodate a change in the angle of inclination of the stairway, as during a mine convergence or divergence. without causing said steps to move out of their said generally horizontal position; a generally horizontal landing attached to the supports adjacent upper ends thereof; and means for fastening the landing to an upper surface of the air crossing thereby to secure the stairway to the air crossing and set the angle of inclination of the steps.

Claim 11

Dependent Claim 20 words

A stairway as set forth in claim 7 including handrails mounted on the steps adjacent opposite sides of the stairway.

Claim 12

Dependent Claim 156 words

A stairway for a mine air crossing installed in a mine passageway, comprising: a pair of elongate generally parallel supports at opposite sides of the stairway, each support comprising upper and lower parallel stringers disposed one above the other at a respective side of the stairway; a plurality of generally horizontal steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports; two generally horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway whereby said steps remain generally horizontal regardless of the angle of inclination of the stairway; and a pair of variable length columns, each mounted on a said step adjacent upper ends of the supports, said columns having lower ends for resting on a mine floor to at least partially support the steps and supports.

Claim 13

Dependent Claim 156 words

A stairway for a mine air crossing installed in a mine passageway, comprising: a pair of elongate generally parallel supports at opposite sides of the stairway, each support comprising upper and lower parallel stringers disposed one above the other at a respective side of the stairway; a plurality of generally horizontal steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports; two generally horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway whereby said steps remain generally horizontal regardless of the angle of inclination of the stairway; and a pair of variable length columns, each mounted on a said step adjacent upper ends of the supports, said columns having lower ends for resting on a mine floor to at least partially support the steps and supports.

Claim 14

Dependent Claim 22 words

A stairway as set forth in claim 9 wherein the steps include a top step and the columns engage the top step.

Claim 15

Dependent Claim 26 words

A stairway as set forth in claim 10 including anchor plates secured to lower ends of the columns and adapted for securement to a mine floor.

Claim 16

Dependent Claim 17 words

A stairway as set forth in claim 11 including a landing extending rearward from said top step.

Claim 17

Dependent Claim 200 words

An air crossing system for a mine comprising: a pair of generally vertical sidewalls with upper edges, said sidewalls being in spaced apart relation; a deck extending between the sidewalls and secured thereto adjacent the upper edges of the sidewalls; a stairway positioned adjacent at least one of the sidewalls and including a pair of elongate generally parallel supports at opposite sides of the stairway, each support comprising upper and lower stringers disposed one above the other at a respective side of the stairway, a plurality of generally horizontal steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports, and two pivot connections between each end of each step and the upper and lower stringers of a respective support forming parallelograms at opposite sides of the stairway, each parallelogram having a first pair of parallel sides formed by said upper and lower stringers and a second pair of opposing sides formed by two of said steps held in fixed generally horizontal positions whereby upon a mine convergence or divergence, said upper and lower stringers shift longitudinally relative to one another and said steps remain in said generally horizontal positions.

Claim 18

Dependent Claim 200 words

An air crossing system for a mine comprising: a pair of generally vertical sidewalls with upper edges, said sidewalls being in spaced apart relation; a deck extending between the sidewalls and secured thereto adjacent the upper edges of the sidewalls; a stairway positioned adjacent at least one of the sidewalls and including a pair of elongate generally parallel supports at opposite sides of the stairway, each support comprising upper and lower stringers disposed one above the other at a respective side of the stairway, a plurality of generally horizontal steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports, and two pivot connections between each end of each step and the upper and lower stringers of a respective support forming parallelograms at opposite sides of the stairway, each parallelogram having a first pair of parallel sides formed by said upper and lower stringers and a second pair of opposing sides formed by two of said steps held in fixed generally horizontal positions whereby upon a mine convergence or divergence, said upper and lower stringers shift longitudinally relative to one another and said steps remain in said generally horizontal positions.

Claim 19

Dependent Claim 25 words

An air crossing system as set forth in claim 13 wherein said stairway includes handrails mounted on the steps adjacent opposite sides of the stairway.

Claim 20

Dependent Claim 64 words

An air crossing system as set forth in claim 14 wherein said steps includes a top step, said air crossing system further comprising: a generally horizontal landing extending rearward from said top step; and means for fastening the landing to an upper surface of the deck thereby to secure the stairway to the air crossing and set the angle of inclination of the steps.

Claim 21

Dependent Claim 203 words

A stairway for use with an elevated deck in a mine to form a walkway extending over an area to be traversed, said stairway comprising: a pair of elongate supports at opposite sides of the stairway, each support comprising upper and lower stringers disposed one above the other at a respective side of the stairway; a plurality of steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports; two generally horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway permitting longitudinal shifting of said upper and lower stringers relative to one another after said stairway is installed and allowing said steps to remain in a generally fixed angular orientation relative to the deck regardless of the angle of inclination of the stairway and regardless of a mine convergence or divergence causing a longitudinal shift of an upper stringer relative to a lower stringer after installation of the stairway; and retaining means secured to at least one step of said stairway for retaining the steps in said fixed angular orientation relative to the deck.

Claim 22

Dependent Claim 203 words

A stairway for use with an elevated deck in a mine to form a walkway extending over an area to be traversed, said stairway comprising: a pair of elongate supports at opposite sides of the stairway, each support comprising upper and lower stringers disposed one above the other at a respective side of the stairway; a plurality of steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports; two generally horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway permitting longitudinal shifting of said upper and lower stringers relative to one another after said stairway is installed and allowing said steps to remain in a generally fixed angular orientation relative to the deck regardless of the angle of inclination of the stairway and regardless of a mine convergence or divergence causing a longitudinal shift of an upper stringer relative to a lower stringer after installation of the stairway; and retaining means secured to at least one step of said stairway for retaining the steps in said fixed angular orientation relative to the deck.

Claim 23

Dependent Claim 61 words

A stairway as set forth in claim 16 further comprising: handrails mounted on the steps adjacent opposite sides of the stairway; and each handrail comprising a plurality of generally vertical posts each having a lower end attached to a respective step and an upper end, and a hand bar having generally horizontal pivot connections with the posts adjacent their upper ends.

Claim 24

Dependent Claim 26 words

A stairway as set forth in claim 17 wherein said posts are positioned forward of the front edge of the steps on which they are attached.

Claim 25

Dependent Claim 48 words

A stairway as set forth in claim 17 wherein said pivot connections with each said stringer being in a row with the row of pivot connections in one said stringer being generally parallel to the row of pivot connections in the other stringer comprising a respective said support.

Claim 26

Dependent Claim 35 words

A stairway as set forth in claim 16 wherein said steps include a top step and said retaining means comprises a landing secured to said top step and adapted to be affixed to said deck.

Claim 27

Dependent Claim 37 words

A stairway as set forth in claim 16 wherein said steps include a top step and retaining means comprises a pair of height adjustable columns secured to said top step adjacent opposite ends of said top step.

Claim 28

Dependent Claim 57 words

A stairway as set forth in claim 16 wherein said retaining means includes a pair of brackets each secured to respective upper and lower stringers a respective support, said brackets each being part of a respective said parallelogram, said retaining means further includes a pair of height adjustable columns each rigidly affixed to a respective said bracket.

Claim 29

Dependent Claim 42 words

A stairway as set forth in claim 16 wherein said steps include a top step and said retaining means includes a landing extending rearward from said top step and further includes a pair of height adjustable columns rigidly affixed to said landing.

Claim 30

Dependent Claim 22 words

A stairway as set forth in claim 16 wherein each step inclines slightly downward from the back edge to the front edge.

Claim 31

Dependent Claim 18 words

A stairway as set forth in claim 24 wherein said incline is between about 1 to 3 degrees.

Claim 32

Dependent Claim 27 words

A stairway as set forth in claim 16 wherein said retaining means includes a landing extending rearward from said stairway and secured to the upper mine floor.

Claim 33

Dependent Claim 60 words

A stairway as set forth in claim 7 installed in mine wherein said steps have bottom surfaces and said connections are pivot connections including elongate rods extending through the holes in the stringers and through channel members secured to the bottom surfaces of the steps, said pivot connections being pivotal after installation of the stairway on the mine air crossing.

Claim 34

Dependent Claim 200 words

A stairway attached to an elevated deck in a mine to form a walkway extending over an area to be traversed, said stairway comprising: a pair of elongate supports at opposite sides of the stairway, each support comprising upper and lower stringers disposed one above the other at a respective side of the stairway; a plurality of steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports; two generally horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway permitting longitudinal shifting of said upper and lower stringers relative to one another after said stairway is installed whereby said steps remain in a generally fixed angular position relative to the deck regardless of the angle of inclination of the stairway and regardless of a mine convergence or divergence causing a longitudinal shift of an upper stringer relative to a lower stringer after installation of the stairway; and retaining means secured to at least one step of said stairway for retaining the steps in said fixed angular position relative to the deck.

Claim 35

Dependent Claim 200 words

A stairway attached to an elevated deck in a mine to form a walkway extending over an area to be traversed, said stairway comprising: a pair of elongate supports at opposite sides of the stairway, each support comprising upper and lower stringers disposed one above the other at a respective side of the stairway; a plurality of steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports; two generally horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway permitting longitudinal shifting of said upper and lower stringers relative to one another after said stairway is installed whereby said steps remain in a generally fixed angular position relative to the deck regardless of the angle of inclination of the stairway and regardless of a mine convergence or divergence causing a longitudinal shift of an upper stringer relative to a lower stringer after installation of the stairway; and retaining means secured to at least one step of said stairway for retaining the steps in said fixed angular position relative to the deck.

Claim 36

Dependent Claim 35 words

A stairway as set forth in claim 28 wherein said steps include a top step and said retaining means comprises a landing secured to said top step and adapted to be affixed to said deck.

Claim 37

Dependent Claim 36 words

A stairway as set forth in claim 28 wherein said steps include a top step and said retaining means comprises a pair of columns secured to said top step adjacent opposite ends of said top step.

Claim 38

Dependent Claim 58 words

A stairway as set forth in claim 28 wherein said retaining means includes a pair of brackets each secured to respective upper and lower stringers of a respective support, said brackets each being part of a respective said parallelogram, said retaining means further includes a pair of height adjustable columns each rigidly affixed to a respective said bracket.

Claim 39

Dependent Claim 40 words

A stairway as set forth in claim 28 wherein said steps include a top step and said retaining means includes a landing extending rearward from said top step and further includes a pair of columns rigidly affixed to said landing.

Claim 40

Dependent Claim 141 words

A stairway for use with an elevated deck in a mine to form a walkway extending over an area to be traversed, said stairway comprising: a pair of elongate supports at opposite sides of the stairway, each support comprising upper and lower stringers disposed one above the other at a respective side of the stairway, the stringers having lower ends adapted to rest on a surface in the mine without fixed attachment thereto; a plurality of steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports; and two generally horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway permitting longitudinal shifting of said upper and lower stringers relative to one another.

Claim 41

Dependent Claim 141 words

A stairway for use with an elevated deck in a mine to form a walkway extending over an area to be traversed, said stairway comprising: a pair of elongate supports at opposite sides of the stairway, each support comprising upper and lower stringers disposed one above the other at a respective side of the stairway, the stringers having lower ends adapted to rest on a surface in the mine without fixed attachment thereto; a plurality of steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports; and two generally horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway permitting longitudinal shifting of said upper and lower stringers relative to one another.

Claim 42

Dependent Claim 29 words

A stairway as set forth in claim 33 installed in a mine wherein longitudinal shifting of said upper and lower stringers relative to one another is permitted after installation.

Claim 43

Dependent Claim 36 words

A stairway as set forth in claim 33 further comprising retaining means secured to said stairway adjacent an upper end of the stairway for retaining the steps in a fixed angular position relative to the deck.

Claim 44

Dependent Claim 79 words

A stairway as set forth in claim 35 installed in a mine wherein said lower ends rest on a surface in the mine without fixed attachment thereto and wherein said upper and lower stringers are freely longitudinally movable relative to one another after installation of the stairway to accommodate a change in the angle of inclination of the stairway, as during a mine convergence or divergence, without causing said steps to move out of their said fixed angular position.

Claim 45

Dependent Claim 163 words

A stairway for a mine air crossing installed in a mine passageway, comprising: a pair of elongate generally parallel supports at opposite sides of the stairway, each support comprising upper and lower parallel stringers disposed one above the other at a respective side of the stairway; a plurality of steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports; two generally horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway permitting longitudinal shifting of said upper and lower stringers relative to one another after said stairway is installed whereby said steps remain in the same angular position regardless of the angle of inclination of the stairway; and a pair of columns for supporting the stairway, said columns having lower ends for resting on a mine floor to at least partially support the stairway.

Claim 46

Dependent Claim 163 words

A stairway for a mine air crossing installed in a mine passageway, comprising: a pair of elongate generally parallel supports at opposite sides of the stairway, each support comprising upper and lower parallel stringers disposed one above the other at a respective side of the stairway; a plurality of steps extending between the supports, each step having a front edge, a rear edge, and opposite ends positioned adjacent respective supports; two generally horizontal pivot connections between each end of each step and the upper and lower stringers of a respective support to form parallelograms at opposite sides of the stairway permitting longitudinal shifting of said upper and lower stringers relative to one another after said stairway is installed whereby said steps remain in the same angular position regardless of the angle of inclination of the stairway; and a pair of columns for supporting the stairway, said columns having lower ends for resting on a mine floor to at least partially support the stairway.

Claim 47

Dependent Claim 22 words

A stairway as set forth in claim 37 wherein the steps include a top step and the columns engage the top step.

Claim 48

Dependent Claim 17 words

A stairway as set forth in claim 37 including a landing extending rearward from said top step.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2004-07-09	2005-01-08	2005-07-10	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2008-07-09	2009-01-08	2009-07-10	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2012-07-09	2013-01-08	2013-07-10	$7700.00	Window Closed / Lapsed

Adjustable stairway for use with an overcast in a mine

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