Adjustable manhole installation and method of adjustment

Abstract

A manhole installation is provided that permits the height of manhole openings to be easily adjusted when road or ground surface levels have changed. The manhole installation comprises concentric manhole tube members that can be raised or lowered relative to each other are provided. The concentric tube members are each furnished with cooperating elements which, when engaged with each other, permit a graduated raising or lowering of one tube member in relation to the other. Existing manhole installations can also be modified so that positioning the opening of such manholes with a repaired road surface is facilitated.

What is claimed is:  
     
         1 . An adjustable manhole installation comprising: 
 a first generally tubular member having an outer surface, and a first plurality of cooperative height-adjusting engagement elements spaced apart on its external circumference and fixed on the outer surface;    a second generally tubular member, having an internal diameter greater than the external diameter of the first generally tubular member such that the first member fits concentrically within the second member, the second member further having an interior surface having a second complimentary plurality of cooperative height-adjusting engagement elements spaced apart on its internal circumference and fixed thereon for cooperative engagement with the first plurality of engagement elements;    the first generally tubular member being held generally concentrically within the second generally tubular member by the engagement of the first plurality of height-adjusting engagement elements with the second plurality of height-adjusting engagement elements.    
     
     
         2 . The adjustable manhole installation of  claim 1  wherein the first and second generally tubular members each comprises a top rim, and when the first tubular member is held concentrically within the second tubular member, the top rim of the first tubular member extends higher than the top rim of the second tubular member.  
     
     
         3 . The adjustable manhole installation of  claim 1  wherein the first tubular member is of a shorter length than the second tubular member.  
     
     
         4 . The adjustable manhole installation of  claim 1  wherein the tubular members are comprised of cast iron.  
     
     
         5 . The adjustable manhole installation of  claim 4  wherein each of the plurality of engagement elements of the tubular members is fixed to a tubular member by fasteners.  
     
     
         6 . The adjustable manhole installation of  claim 4  wherein each engagement element is cast simultaneously with the tubular member in a unitary casting.  
     
     
         7 . The adjustable manhole installation of  claim 1  wherein the tubular members are comprised of cast concrete.  
     
     
         8 . The adjustable manhole installation of  claim 7  wherein each of the plurality of engagement elements of the tubular members is fixed to a tubular member by fasteners.  
     
     
         9 . The adjustable manhole installation of  claim 7  wherein each engagement element is cast simultaneously with the tubular member in a unitary casting.  
     
     
         10 . The adjustable manhole installation of  claim 1  wherein each engagement element is affixed to a tubular shaped member with an adhesive.  
     
     
         11 . The adjustable manhole installation of  claim 1  wherein each engagement element comprises a thin flange formed into a series of steps and risers.  
     
     
         12 . The adjustable manhole installation of  claim 1  wherein each engagement element comprises a block element placed into a stair-shaped formation.  
     
     
         13 . The adjustable manhole installation of  claim 1  wherein each engagement element comprises a thin generally horizontal flange and each tubular member has a series of thin generally horizontal flanges, each series of flanges being spaced generally in parallel orientation generally vertically on the cooperating walls of the respective tubular members in a manner similar to the rungs of a ladder such that at least one of the flanges of the series of flanges on the first tubular member engages at least one of the flanges of the series of flanges on the second tubular member.  
     
     
         14 . The adjustable manhole installation of  claim 1  wherein each engagement element comprises gear-teeth-shaped support elements, which engage each other in a manner similar to the meshing of gears in a machine.  
     
     
         15 . An adjustable manhole installation comprising: 
 a first generally tubular member having an outer surface, and a first plurality of stair-shaped elements spaced apart on its external circumference and fixed on the outer surface;    a second generally tubular member having an internal diameter greater than the external diameter of the first generally tubular member such that the first member fits concentrically within the second member, the second member further having an interior surface having a second complimentary plurality of stair-shaped elements spaced apart on its internal circumference and fixed thereon for cooperative engagement with the first plurality of stair-shaped elements;    the first generally tubular member being held generally concentrically within the second generally tubular member by the engagement of the first plurality of stair-shaped elements with the second plurality of stair-shaped elements.    
     
     
         16 . The adjustable manhole installation of  claim 15  wherein the first and second generally tubular members each comprises a top rim, and when the first tubular member is held concentrically within the second tubular member, the top rim of the first tubular member extends higher than the top rim of the second tubular member.  
     
     
         17 . The adjustable manhole installation of  claim 15  wherein the first tubular member is of a shorter length than the second tubular member.  
     
     
         18 . The adjustable manhole installation of  claim 15  wherein the tubular members are comprised of cast iron.  
     
     
         19 . The adjustable manhole installation of  claim 18  wherein each of the plurality of stair-shaped elements of the tubular members is fixed to a tubular member by fasteners.  
     
     
         20 . The adjustable manhole installation of  claim 18  wherein the respective stair-shaped elements and generally tubular members are a unitary casting.  
     
     
         21 . The adjustable manhole installation of  claim 15  wherein each stair-shaped element is affixed to a tubular shaped member with an adhesive.  
     
     
         22 . The adjustable manhole installation of  claim 15  wherein each stair-shaped element comprises a thin flange formed into a series of steps and risers.  
     
     
         23 . An adjustable manhole installation comprising: 
 a first generally tubular member having an outer surface, and a first plurality of block-shaped supports arranged in a stair-shaped formation spaced apart on its external circumference and fixed on the outer surface;    a second generally tubular member having an internal diameter greater than the external diameter of the first generally tubular member such that the first member fits concentrically within the second member, the second member further having an interior surface having a second complimentary plurality of block-shaped supports spaced apart on its internal circumference and fixed thereon for cooperative engagement with the first plurality of block-shaped supports;    the first generally tubular member being held generally concentrically within the second generally tubular member by the engagement of the first plurality of block-shaped supports with the second plurality of block-shaped supports.    
     
     
         24 . The adjustable manhole installation of  claim 23  wherein the first and second generally tubular members each comprises a top rim, the second tubular member being adjustable relative to the second tubular member such that the top rim of the second tubular member is moveable relative to the top rim of the first tubular member.  
     
     
         25 . An adjustable manhole installation for use at and below the surface of the ground or a road surface, comprising: 
 a first tubular member having a top surface, an outer surface and a first series of stair-shaped elements about its outer surface;    a second tubular member having an internal diameter greater than the external diameter of the first tubular member, further having an interior surface and a corresponding second series of stair-shaped elements about the interior surface;    the first tubular member fitting generally concentrically within the second tubular member so that the first series of stair-shaped elements engages the second series of stair-shaped elements such that the first tubular member can be set at a desired height relative to the ground or road surface;    the first tubular member being adjustable, within the second tubular member such that the second tubular member can be raised or lowered, within the first tubular member, relative to the ground or road surface, in graduated steps.    
     
     
         26 . The manhole installation of  claim 25  wherein the first and second tubular members are constructed of cast iron and the stair-shaped elements are cast integrally with the tubular members.  
     
     
         27 . The manhole installation of  claim 25  wherein the first and second tubular members each comprise several series of stair-shaped elements such that the stair-shaped elements are substantially about the entire inner circumference of the first tubular member and the outer circumference of the second tubular member.  
     
     
         28 . A method of adjusting a manhole installation to level its opening with a ground or road surface, including the steps of: 
 providing a manhole installation having a first tubular member having an interior surface, and a second tubular member having a smaller diameter than the diameter of the first tubular member and an exterior surface;    providing a plurality of stair-shaped support elements, spaced apart, on both the interior surface of the first tubular member and the exterior surface of the second tubular member;    placing the second tubular member within the first tubular member at a desired height within the first tubular member; and,    rotating the second tubular member, within the first tubular member, to cooperatively engage the stair-shaped elements of the first tubular member with the stair-shaped elements of the second tubular member.    
     
     
         29 . The method of adjusting a manhole installation of  claim 28 , including the step of lifting and rotating the second tubular member, within the first tubular member, engaging the stair shaped support elements of the second tubular member with different stair shaped support elements of the first tubular member such that a new desirable height for the second tubular member is set, when the ground surface level has been changed.  
     
     
         30 . The method of adjusting a manhole installation of  claim 28 , including the step of providing a top rim on the second tubular member such that the top rim is placed at the ground surface level.