Method and mechanism for opening and closing of manhole covers

Abstract

A cover for opening and closing a manhole includes a movable cover and a base cover, the movable cover and the base cover being connected to each other by a shaft manufactured from an aluminium bronze alloy that passes through at least one first hinge part fastened to the movable cover and at least two second hinge parts fastened to the cover base, the first hinge part being fastened perpendicularly to the second hinge parts. In this way, it is possible to manufacture robust manhole covers offering good comfort to a driver of a car, since the movable cover may be manufactured so that the distance between an outer rim of the movable cover and the base cover is minimized.

1 - 8 . (canceled) 
   
   
       9 . A cover adapted to opening and closing a manhole, said cover consisting of a movable cover ( 1 ) and a base cover ( 2 ), said movable cover being connected to the cover base by a shaft ( 11 ), wherein the shaft ( 11 ) is passed through at least a first hinge part ( 16 ) fastened to the movable cover ( 1 ) and passed through at least two second hinge parts ( 10 ) fastened to the cover base ( 2 ), said first hinge part being fastened perpendicular relative to the two second hinge parts. 
   
   
       10 . A cover according to  claim 9 , wherein two shafts ( 11 ) are passed through two first hinge parts and four second hinge parts. 
   
   
       11 . A cover according to  claim 9 , wherein the second hinge parts are formed by two legs that are perpendicular relative to each other. 
   
   
       12 . A cover according to  claim 9 , wherein the material thickness of the second hinge parts ( 10 ) between the shaft ( 11 ) and the movable cover in the direction of the movable cover is smaller than the cross-sectional diameter of the shaft. 
   
   
       13 . A cover according to  claim 12 , wherein the material thickness of the second hinge parts is smaller than 0.3 times the cross-sectional diameter of the shaft. 
   
   
       14 . A cover according to  claim 9 , wherein the shaft ( 11 ) is made of an aluminium bronze alloy.