Simplified staircase

Abstract

A simplified staircase 1 includes a plurality of girders 3 that form a plurality of steps Each of the girders 3 includes one or more first protrusions 17 that protrude from a front side of an upper surface of each of the girders 3 . Each of the girders 3 further includes one or more second protrusions 15 that protrude from a rear side of the upper surface of the girder 3 . The one or more second protrusions 15 are higher than the one or more first protrusions 17 in height.

1 . A simplified staircase installed on a sloping ground, comprising:
 a plurality of girders forming a plurality of steps;   one or more longitudinal connecting members connecting the plurality of girders in a direction with an interval between an adjacent pair of the plurality of girders;   a plurality of fixing piles fixing the plurality of girders to the sloping ground, wherein   at least one of the plurality of girders includes:   one or more first protrusions that protrude from a front side of an upper surface of the at least one of the plurality of girders; and   one or more second protrusions that protrude from a rear side of the upper surface of the at least one of the plurality of girders, and   the one or more second protrusions are higher than the one or more first protrusions in height.   
     
     
         2 . The simplified staircase according to  claim 1 , wherein the one or more second protrusions are larger than the one or more first protrusions in length. 
     
     
         3 . The simplified staircase according to  claim 2 , wherein the one or more second protrusions are larger than the one or more first protrusions in breadth. 
     
     
         4 . The simplified staircase according to  claim 1 , wherein the one or more first protrusions or the one or more second protrusions are elongated and bent in a wavy manner in a lateral direction in a plan view. 
     
     
         5 . The simplified staircase according to  claim 1 , wherein
 at least one of the plurality of girders includes:
 a cylindrical portion that is configured to receive an arch portion or a heel portion of a sole of a user of the simplified staircase; and 
 a brim that protrudes forward from a front end of the cylindrical portion to receive a front side of the sole of the user of the simplified staircase, the one or more first protrusions are formed on an upper surface of the brim, and 
   the one or more second protrusions are formed on an upper surface of the cylindrical portion.   
     
     
         6 . The simplified staircase according to  claim 5 , wherein the one or more second protrusions are formed on the upper surface of the cylindrical surface at a position around a rear end of the cylindrical portion. 
     
     
         7 . The simplified staircase according to  claim 5 , wherein the upper surface of the cylindrical portion is curved in a side view to protrude from the upper surface of the brim. 
     
     
         8 . The simplified staircase according to  claim 5 , wherein
 the cylindrical portion has a front half portion extending from a highest point of the upper surface of the cylindrical portion to a border between the cylindrical portion and the brim, and   the front half portion of the cylindrical portion tilts toward a diagonally rearward upper side.   
     
     
         9 . The simplified staircase according to  claim 1 , wherein the one or more longitudinal connecting members are fixed to the plurality of girders by the plurality of fixing piles without using an additional fixing member. 
     
     
         10 . The simplified staircase according to  claim 1 , wherein each of the plurality of girders includes a horizontal connecting mechanism that is configured to connect the girder with another girder in a lateral direction. 
     
     
         11 . A girder that constitutes one step of a simplified staircase installed on a sloping ground, the girder comprising:
 an upper surface that is configured to receive a sole of a user of the simplified staircase;   one or more first protrusions that protrude from a front side of an upper surface of the girder; and   one or more second protrusions that protrude from a rear side of the upper surface of the girder, wherein   the one or more second protrusions are higher than the one or more first protrusions in height.   
     
     
         12 . A simplified staircase, comprising:
 a first girder having a first surface, a second surface, first protrusions protruding from a front side of the first surface, second protrusions protruding from a rear side of the first surface, a through hole extending through a thickness of the first girder between the first and second surface;   a second girder; and   a connector connecting the first girder and the second girder,   wherein the first protrusions have a first height, and the second protrusions have a second height greater than the first height.   
     
     
         13 . The simplified staircase of  claim 12 , wherein the first side and the second side are nonparallel. 
     
     
         14 . The simplified staircase according to  claim 13 , wherein the first girder includes:
 a cylindrical portion that is configured to receive an arch portion or a heel portion of a sole of a user of the simplified staircase; and   a brim that protrudes forward from a front end of the cylindrical portion to receive a front side of the sole of the user of the simplified staircase, and   the first protrusions are formed on an upper surface of the brim, and   the second protrusions are formed on an upper surface of the cylindrical portion.