Abstract: An assembly for adjusting the elevation of a structure such as a manhole or a catch basin to be surrounded by pavement. A one-piece is formed to be inserted between a base rim and a cover of the structure. A lower member of the adapter is received in the base rim to be supported on an internal shoulder. An upper member extends outwardly of the lower member to receive the cover and upwardly to engage the upper end of the base rim and form an upward extension of the rim. The elevation of the structure may be increased by inserting the adapter between the base rim shoulder and the cover and decreased by removing the adapter from between the base rim shoulder and the cover. Additional adapters of identical construction may be inserted to further increase the elevation of the structure, all the adapters being nestable within one another.

Abstract: An assembly for adjusting the elevation of a structure such as a manhole or a catch basin to be surrounded by pavement. A one-piece is formed to be inserted between a base rim and a cover of the structure. A lower member of the adapter is received in the base rim to be supported on an internal shoulder. An upper member extends outwardly of the lower member to receive the cover and upwardly to engage the upper end of the base rim and form an upward extension of the rim. The elevation of the structure may be increased by inserting the adapter between the base rim shoulder and the cover and decreased by removing the adapter from between the base rim shoulder and the cover. Additional adapters of identical construction may be inserted to further increase the elevation of the structure, all the adapters being nestable within one another.

Abstract: An assembly for adjusting the elevation of a structure such as a manhole or a catch basin to be surrounded by pavement. A one-piece is formed to be inserted between a base rim and a cover of the structure. A lower member of the adapter is received in the base rim to be supported on an internal shoulder. An upper member extends outwardly of the lower member to receive the cover and upwardly to engage the upper end of the base rim and form an upward extension of the rim. The elevation of the structure may be increased by inserting the adapter between the base rim shoulder and the cover and decreased by removing the adapter from between the base rim shoulder and the cover. Additional adapters of identical construction may be inserted to further increase the elevation of the structure, all the adapters being nestable within one another.

Abstract: An apparatus and method for supporting a dynamic load relative to a foundation, such as a vehicle relative to the road, by a hydraulic system that monitors the movement of the load and adds or removes hydraulic fluid from the system to compensate for the load change. The hydraulic system is preferably one or more hydraulic cylinders that have a first chamber operably connected to the load and a second chamber operably connected to the foundation. The first and second chamber are connected by a valve. The valve is connected to the second chamber and a source of pressurized fluid with a reservoir. The first chamber senses the load change and the valve adds fluid from the pressurized fluid source to the second chamber or removes fluid from the second chamber to the reservoir to compensate for the change in the load and maintain the load in substantially the same position relative to the foundation.