Method and system for walkway with unsupported end

Abstract

Methods and systems for stairways or other walkways supported at only one end provide a plurality of stair treads are attached to a support beam, a pair of mounting brackets disposed at either side of a support beam bottom end rotatably connected to the support beam by a pivot bolt, the mounting brackets connected to a base, the base connected to a load bearing structure. A support bolt is disposed through the mounting brackets and below a bottom surface of the support beam. Locking means pivotally connected to the support beam engage a base mounting plate and restrain the stairway from at least one of pivoting upward about the pivot bolt or pivoting downward about the pivot bolt. Operative loads transfer from the support beam into the support brackets through the pivot bolt and support bolt and through the base into the load bearing structure.

1 . A stairway, comprising:
 a support beam;   a plurality of stair treads attached to said beam;   a pair of mounting brackets disposed at either side of a support beam bottom end and rotatably connected to the support beam by a pivot bolt, the mounting brackets further connected to a base, the base connected to a load bearing structure;   a support bolt disposed through the mounting brackets and below a bottom surface of the support beam; and   a locking means pivotally connected to the support beam and configured to engage a base mounting plate and thereby restrain the stairway from at least one of pivoting upward about the pivot bolt or pivoting downward about the pivot bolt;   wherein the support beam is configured to pivot downward about the pivot bolt to rest upon the support bolt in a downward deployment and pivot upward about the pivot bolt into a non-deployed orientation; and   wherein the support beam is configured to transfer operative loads upon the stair treads aligned in the support beam downward deployment and with an opposite upper support beam end unsupported from the support beam bottom end through leverage into the support brackets through the pivot bolt and support bolt, the support brackets thereby configured to transfer all the stair tread operative loads through the base into the load bearing structure, and wherein said upper beam end is free of connection to the base or the load bearing structure or any other operative load-supporting structure.   
   
   
       2 . The stairway of  claim 1 , the pivotally connected locking means comprising a lock bar having a top end and a bottom edge, the lock bar top end defining a bolt aperture, and a pivot bolt rotatably conveyed through the pivot bolt aperture;
 the support beam defining an aperture slot projecting inward from a support beam bottom edge and configured to allow the lock bar to pivot downward and into the aperture; and   the stairway further comprising a mounting plate disposed between the support brackets and the base;   wherein the lock bar is configured to hang downward from the pivot bolt within the support beam aperture slot and form an inward negative vertical locking position angle with respect to a vertical orientation parallel to a gravitational force vector, the lock bar bottom edge thereby aligned above and spaced from a top surface of the base mounting plate, and wherein pivoting of the support beam upwards about the pivot bolt causes the lock bar bottom edge to be driven into base mounting plate top surface, the lock bar thereby constraining the stairway support beam from moving upward.   
   
   
       3 . The stairway of  claim 2  wherein the inward negative vertical locking position angle is chosen to cause the lock bar bottom edge to be pivoted and driven toward and along the bottom plate surface along an angle vector component in response to forces raising the stair upward about the pivot bolt, the vector component urging the lock bar bottom edge into engagement with the bottom plate surface and thereby preventing the lock bar bottom edge from moving in a direction opposite to the angle vector component and slipping off of the plate surface and out of an engagement with the plate surface. 
   
   
       4 . The stairway of  claim 3 , the base structure comprising a riser, the riser configured to enable access to the locking means and to enable operative movement of the locking means without interference with the load bearing structure; and
 a first step connected to the riser and spaced a lock bar receiving gap from the support brackets and the base mounting plate;   wherein the lock bar is configured to pivot outward and away from alignment of the lock bar bottom edge over the mounting plate top surface and to drop into the lock-arm receiving gap when the stairway is lifted upward.   
   
   
       5 . The stairway of  claim 4  further comprising at least one support beam bottom edge stopper attached to at least one of the support brackets, wherein the support beam bottom edge rests against the stopper when the stairway is deployed in an upward/stowed position with a bottommost stair tread front edge spaced from the first step. 
   
   
       6 . The stairway of  claim 5  wherein the at least one support beam bottom edge stopper is an eccentric cam. 
   
   
       7 . The stairway of  claim 6  wherein the lock bar bottom edge spacing distance is from about 0.005 inches to about 0.007 inches, and the inward negative vertical locking position angle is from about six degrees to about seven degrees from the vertical orientation. 
   
   
       8 . The stairway of  claim 7  wherein the lock bar pivot bolt aperture is formed off-center in the lock bar top end more proximate to an inside edge of the lock bar then a lock bar outside edge arrayed facing the lock bar receiving gap, the off-center alignment configured to cause the lock bar to hang downward from the pivot bolt and form the inward negative vertical locking position angle in response to gravitational forces acting on the lock bar along the vertical orientation. 
   
   
       9 . The stairway of  claim 7 , further comprising:
 a lock bar arm rotatably attached to the lock bar;   spring-loaded means attached to the lock bar arm and configured to urge the lock bar arm and the lock bar inward toward the mounting plate; and   a pedal means attached to the lock bar arm and configured to move the lock bar arm and the lock bar outward away from mounting plate in response to a user pushing the pedal means, the outward lock bar movement causing the lock bar to pivot outward and into an alignment enabling the lock bar to drop downward into the lock-bar spacing gap with pivoting of the stairway upward.   
   
   
       10 . The stairway of  claim 9 , the lock bar further comprising an internal lock bar notch having a lower lip;
 wherein the spring-loaded lock bar arm is configured to drive an internal lock bar notch surface into contact with an inner edge surface of the base mounting plate and dispose the notch lip spaced below a base mounting plate lower surface a lip spacing distance.   
   
   
       11 . The stairway of  claim 10  wherein the lower lip is oriented at a positive angle with a horizontal orientation normal to the vertical orientation. 
   
   
       12 . The stairway of  claim 10  wherein the lower lip horizontal orientation angle is about 10 degrees. 
   
   
       13 . A method for supporting a stairway at only one bottom end, comprising:
 disposing a plurality of stair treads along a support beam;   rotatably connecting a pair of mounting brackets at either side of a support beam bottom end through a pivot bolt;   connecting the mounting brackets to a base;   connecting the base to a load bearing structure;   disposing a support bolt through the mounting brackets and below a bottom surface of the support beam;   pivotally connecting a locking means to the support beam;   the locking means engaging a base mounting plate and thereby restraining the stairway from at least one of pivoting upward about the pivot bolt or pivoting downward about the pivot bolt;   the support beam pivoting downward about the pivot bolt to rest upon the support bolt in a downward deployment and pivoting upward about the pivot bolt into a non-deployed orientation; and   the support beam transferring operative loads from the stair treads aligned in the support beam downward deployment and with an opposite upper support beam end unsupported from the support beam bottom end through leverage into the support brackets through the pivot bolt and support bolt, the support brackets thereby transferring all the stair tread operative loads through the base into the load bearing structure, the upper beam end free of connection to the base or the load bearing structure or any other operative load-supporting structure.   
   
   
       14 . The method of  claim 13 , the pivotally connected locking means comprising a lock bar having a top end and a bottom edge;
 the lock bar top end defining a bolt aperture;   a pivot bolt rotatably connecting the lock bar top end to a lock means base block through the pivot bolt aperture;   the support beam defining an aperture slot projecting inward from a support beam bottom edge and configured to allow the lock bar to pivot downward and into the aperture; and   disposing a mounting plate between the support brackets and the base;   the lock bar hanging downward from the pivot bolt within the support beam aperture slot and forming an inward negative vertical locking position angle with respect to a vertical orientation parallel to a gravitational force vector, a lock bar bottom edge thereby aligned above and spaced from a top surface of the base mounting plate, and wherein pivoting of the support beam upwards about the pivot bolt causes the lock bar bottom edge to be driven into base mounting plate top surface, the lock bar thereby constraining the stairway support beam from moving upward.   
   
   
       15 . The method of  claim 14 , comprising:
 the inward negative vertical locking position angle causing the lock bar bottom edge to be pivoted and driven toward and along the bottom plate surface along an angle vector component in response to forces raising the stair upward about the pivot bolt; and   the vector component urging the lock bar bottom edge into engagement with the bottom plate surface and preventing the lock bar bottom edge from moving in a direction opposite to the angle vector component and slipping off of the plate surface and out of an engagement with the plate surface.   
   
   
       16 . The method of  claim 15 , comprising:
 a base structure a riser enabling access to the locking means and operative movement of the locking means without interference with the load bearing structure; and   disposing a first step connected to the riser spaced a lock bar receiving gap from the support brackets and the base mounting plate;   wherein the lock bar is configured to pivot outward and away from alignment of the lock bar bottom edge over the mounting plate top surface and to drop into the lock-arm receiving gap when the stairway is lifted upward.   
   
   
       17 . The method of  claim 16  further comprising the support beam bottom edge resting against at least one support beam bottom edge stopper attached to at least one of the support brackets with a bottommost stair tread front edge spaced from the first step when the stairway is deployed in an upward/stowed position. 
   
   
       18 . The method of  claim 17 , comprising:
 forming the lock bar pivot bolt aperture off-center in the lock bar top end more proximate to an inside edge of the lock bar then a lock bar outside edge arrayed facing the lock bar receiving gap;   the off-center alignment causing the lock bar to hang downward from the pivot bolt and form the inward negative vertical locking position angle in response to gravitational forces acting on the lock bar along the vertical orientation.   
   
   
       19 . The method of  claim 17 , comprising:
 rotatably attaching a lock bar arm to the lock bar;   attaching a spring-loaded means to the lock bar arm;   the spring-loaded means urging the lock bar arm and the lock bar inward toward the mounting plate; and   attaching a pedal means to the lock bar arm, the pedal means configured to move the lock bar arm and the lock bar outward away from mounting plate in response to a user pushing the pedal means, said outward lock bar movement causing the lock bar to pivot outward and into an alignment enabling the lock bar to drop downward into the lock-bar spacing gap with pivoting of the stairway upward.   
   
   
       20 . The method of  claim 19 , comprising:
 the lock bar defining an internal lock bar notch having a lower lip;   the spring-loaded lock bar arm driving an internal lock bar notch surface into contact with an inner edge surface of the base mounting plate and disposing the notch lip spaced below a base mounting plate lower surface a lip spacing distance, the lower lip oriented at a positive angle with a horizontal orientation normal to the vertical orientation.