Roller vehicle for ground compaction

A roller vehicle for ground compaction has a ground compacting device operative for compacting ground; and a levelling device for levelling the ground.

BACKGROUND OF THE INVENTION

The present invention relates to devices for ground compaction, which are formed as roller vehicles.

Devices of the above mentioned general type are known in the art. Conventional devices for ground compaction are formed so that they exclusively perform compaction of the ground. However such roller vehicles can not provide levelling of unevenness of the ground. For this purpose, additional levelling vehicles are needed to eliminate the ground unevenness before the compaction.

SUMMARY OF THE INVENTION

Accordingly, it is an object of present invention to provide a roller vehicle for ground compaction which eliminates the disadvantages of the prior art.

More particularly, it is an object of present invention to provide a roller vehicle for ground compaction which is designed so that for levelling and compaction of the ground no longer two separate vehicles must be provided.

In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a roller vehicle which has means for ground compaction, such as for example a trench roller, and additionally is provided with a levelling device.

When the roller vehicle is designed in accordance with the present invention, the same vehicle can be efficiently used to perform both levelling and compaction of the ground. As a result, the whole process of levelling and compaction can be performed in a shorter time and with lower expenses.

In accordance with a preferable embodiment of the invention, the levelling device of the inventive roller vehicle is formed as a blade.

The levelling device can be movable up and down, for easy maneuvering of the roller vehicle. Moreover, any desirable level of the ground surface can be planned.

In accordance with a further embodiment, the levelling device is movable up and down by means of a lifting device. Therefore the displaced ground can not hindered the levelling device during lifting.

The lifting device in accordance with the present invention can be formed in a structurally especially simple manner, when it includes a telescopable extensible and retractable cylinder unit. The cylinder unit can be driven for example from the available hydraulic system.

When the lifting device lifts the levelling device inclinedly upwardly relative to the vehicle, the levelling unit despite the displaced ground is lifted without a high resistance, since then it is moved back to the vehicle from the displaced ground.

When the levelling device is turned to a horizontal, in particular around its central point, the surface to be leveled can be leveled at any desirable angle to the horizontal.

The levelling device can be mounted on an upper part of the vehicle which is vibrationally uncoupled from the ground compacting part. In this manner, the levelling device is protected from vibrations which result from shaking of the ground compacting part. Therefore damages to the levelling device are avoided.

It is advantageous when in accordance with the present invention, the same hydraulic oil, with which the circuit for producing the vibrations of the compacting part, is used in the circuit for lifting and lowering of the levelling device. For this purpose only one valve is needed, to direct the hydraulic oil in a respective one of the circuits.

The upper part of the compacting part can be clamped so as to prevent that the upper part connected with the levelling device, when the levelling device is oriented inclinedly to a horizontal, is also inclined because of the reaction forces. This can be achieved in an especially simple way by hydraulically operating clamping cylinder.

When desired, the levelling device can be controlled manually and/or remotely. Remote control can be performed for example by radio or infrared light.

DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 shows a roller vehicle 10 for ground compaction, in accordance with the present invention.

The roller vehicle 10 is provided at its front end with a levelling device 11 . The Levelling device 11 can be formed for example as a blade. For levelling, the levelling device 11 is moved downwardly, and therefore automatically shaking which is required for compaction is prevented. After finishing the levelling works, the levelling device 11 is displaced upwardly. When the blade reaches the upper end position, the shaking drive which is required for ground compacting is automatically released.

The levelling device 11 is mounted on an upper part 12 . The upper part 12 is vibrationally uncoupled from a ground compacting part 13 . Thereby the levelling device 11 can not be damaged by the shaking of the ground compacting part 13 .

Preferably the same hydraulic oil is used in a circuit for producing vibrations of the ground compacting part 13 and also in the circuit for lifting and lowering of the levelling device 11 .

The levelling device 11 can be controlled both manually and remotely. Preferably the remote control can be performed by radio or infrared light.

The levelling device 11 can be turned at any angle relative to a horizontal. This is especially important for levelling of surfaces which are inclined at a predetermined angle relative to the horizontal.

In accordance with the invention, the upper part 12 of the ground compacting part 13 is clamped, for example by a not shown clamping cylinder. Therefore during levelling of a surface which is inclined at a predetermined angle relative to the horizontal, the upper part 12 is not inclined. When a linkage 20 is turned upwardly, the levelling device 11 is also turned upwardly. By turning of the linkage 20 downwardly, the levelling device 11 can be lowered. The linkage 20 is driven by a not shown hydraulic cylinder-piston unit.

FIGS. 2 a and 2 b show a further embodiment of a roller vehicle which is identified as reference numeral 30 . The roller vehicle 30 has a lifting device 32 for moving a levelling device 31 upwardly in FIG. 2 b and downwardly in FIG. 2 a. The lifting device 32 can be formed for example by a telescopable extendable and retractable cylinder-piston unit. It is to be understood that other embodiments of the lifting device 30 are possible as well. The upper end of the lifting device 32 is arranged closer to the vehicle than the lower end of the lifting device 32 . As a result, the levelling device 31 is liftable and lowerable with an inclination upwardly relative to the vehicle, so that despite the displaced ground, the levelling device 31 can be moved back upwardly. Furthermore, a not shown support can be provided on the lifting device 32 , to prevent bending of the lifting device 32 during levelling.